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|---|---|---|
Tracking down the cause of loss of network connectivity. <p>I have been having issues with short (seconds, but long enough to break a TCP connection) periods of loss of internet connectivity. I have tracked this down to what appears to be an actual loss of connectivity with my router (a BT Home Hub 4, provided by my ISP / landlord, I wont be able to get this changed without a good explanation).</p>
<p>I tried making a simple program using IcmpSendEcho (to 192.168.1.254), which will at these points give error 11010 "Error due to lack of resources." which doesn't seem to really tell me anything more than "ping" does...</p>
<p>Is there anything I can do to get a more detailed explanation, or at least work my way to a conclusion?</p>
<p>I am thinking of monitoring it over direct Ethernet, but I have experienced this even in the same room with WiFi, so don't think there should be that much interference (and if that is possible, what could be a source, how to prove it, and what can be done about it?). But otherwise this is really not something I have ever seen before...</p>
| 0non-cybersec
| Stackexchange |
Buy Bed Sheets Online: Single, Double & King Sized Bed Sheets. Shop from a wide range of cotton bed sheets, single bed sheets, Bed sheet set at bedsheet bazaar.. | 0non-cybersec
| Reddit |
Could not load file or assembly in VS2017 with IIS express. <p>We have a ASP.NET project in the company that runs for 5/6 developers. All Visual Studio 2017 and debug on IIS Express, no crazy setting or anything to make it run.</p>
<p>1 colleague cannot get it to work, he always gets the following exception:</p>
<p><a href="https://i.stack.imgur.com/MsOBz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MsOBz.png" alt="enter image description here"></a></p>
<p>We had this problem a few months back, then out of frustration the PC was re-installed and the problem was gone. He didn't develop for a few weeks and today the problem appeared again.</p>
<p>I searched long and far but it's such a generic error I can't really figure this one out.</p>
<p>When I run the fusion log viewer I see the following result:</p>
<p><a href="https://pastebin.com/aCVZn3EB" rel="nofollow noreferrer">https://pastebin.com/aCVZn3EB</a></p>
<pre><code>The operation failed.
Bind result: hr = 0x80131018. No description available.
Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
Running under executable C:\Program Files\IIS Express\iisexpress.exe
--- A detailed error log follows.
=== Pre-bind state information ===
LOG: DisplayName = System.ServiceModel.Activities, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
(Fully-specified)
LOG: Appbase = file:///C:/Users/User/Projects/project/project.UserSite/
LOG: Initial PrivatePath = C:\Users\User\Projects\project\project.UserSite\bin
LOG: Dynamic Base = C:\Users\User\AppData\Local\Temp\Temporary ASP.NET Files\vs\e0254dae
LOG: Cache Base = C:\Users\User\AppData\Local\Temp\Temporary ASP.NET Files\vs\e0254dae
LOG: AppName = 38c6ff11
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Users\User\Projects\project\project.UserSite\web.config
LOG: Using host configuration file: C:\Users\User\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Binding succeeds. Returns assembly from C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Activities\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Activities.dll.
LOG: Assembly is loaded in default load context.
ERR: Unrecoverable error occurred during pre-download check (hr = 0x80131018).
*** Assembly Binder Log Entry (7/18/2017 @ 8:55:15 AM) ***
</code></pre>
| 0non-cybersec
| Stackexchange |
Shorewall missing from Ubuntu 11.10 default repository?. <p>I'm looking to configure my network using Shorewall on my Ubuntu 11.10 laptop. </p>
<p>When I run <code>apt-cache search</code> it doesn't find Shorewall, is there some other repository I can add it from? </p>
<p>Or is the <a href="http://www.shorewall.net/download.htm" rel="nofollow">Debian package listed on the Shorewall</a> website compatible with Ubuntu 11.10, since Ubuntu is Debian-based?</p>
| 0non-cybersec
| Stackexchange |
High above a waterfall in the Gifford Pinchot National Forest, WA. [OC] [2560x1706]. | 0non-cybersec
| Reddit |
tracker-miner-fs is taking 90% of cpu. <p>tracker-miner-fs is taking 90% of CPU. I am using ubuntu 20.04.</p>
| 0non-cybersec
| Stackexchange |
Django Custom MultiWidget Retaining Old Values. <p>I have created a simple custom <code>MultiValueField</code> and <code>MultiWidget</code> for the purpose of entering a date of birth but allowing separate entry of the day, month and year. The rationale is that the app is for entry of historical data, so one or more of these fields could be unknown. There is also a checkbox that displays 'unknown' on the user-facing site.</p>
<p>I've found that everything works fine, except that when I save an instance of an object in the admin site and go to create a new instance, the blank admin form displays the date values from the previous entry:</p>
<p><a href="https://i.stack.imgur.com/QBejq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QBejq.png" alt="Custom MultiWidget"></a></p>
<p>All those fields should be blank for a new entry.</p>
<p>It looks like the field is not being reinitialised correctly, but I am not sure where this should take place. I have added a workaround by checking in the form whether to reinitialise the fields, but I feel that this should be done in the custom field/widget.</p>
<p>Sample code:</p>
<pre class="lang-py prettyprint-override"><code> class CustomDateWidget(forms.MultiWidget):
"""Custom MultiWidget to allow saving different date values."""
template_name = 'myapp/widgets/custom_date_widget.html'
def __init__(self, attrs=None):
_widgets = (forms.NumberInput(attrs=({'placeholder': 'DD'})),
forms.NumberInput(attrs=({'placeholder': 'MM'})),
forms.NumberInput(attrs=({'placeholder': 'YYYY'})),
forms.CheckboxInput())
super().__init__(_widgets, attrs)
def decompress(self, value):
if value:
return value
else:
return '', '', '', False
def value_from_datadict(self, data, files, name):
value_list = [
widget.value_from_datadict(data, files, name + '_%s' % i)
for i, widget in enumerate(self.widgets)
]
return value_list
class CustomDateField(forms.MultiValueField):
"""Custom MultiValueField to allow saving different date values."""
def __init__(self, **kwargs):
fields = (forms.IntegerField(min_value=1, max_value=31), forms.IntegerField(min_value=1, max_value=12),
forms.IntegerField(min_value=1800, max_value=9999), forms.BooleanField())
super().__init__(fields=fields, widget=CustomDateWidget, require_all_fields=True,
**kwargs)
def compress(self, data_list):
return data_list
class PersonAdminForm(forms.ModelForm):
"""Custom Person admin form."""
date_of_birth = CustomDateField(required=False)
class Meta:
model = Person
fields = '__all__'
def __init__(self, *args, **kwargs):
super(PersonAdminForm, self).__init__(*args, **kwargs)
# Dirty workaround?
if not self.instance.pk:
self.fields['date_of_birth'] = CustomDateField(required=False)
...
</code></pre>
<p>Widget template:</p>
<pre class="lang-html prettyprint-override"><code> <style>
.custom-date-widget-container {
padding-right: 15px;
}
.custom-date-widget td {
width: 25%;
}
.custom-date-widget td > input {
width: 100%;
box-sizing: border-box;
}
</style>
{% spaceless %}
<div class="custom-date-widget-container">
<table class="custom-date-widget">
<thead>
<tr>
<th>Day</th>
<th>Month</th>
<th>Year</th>
<th>Unknown</th>
</tr>
</thead>
<tbody>
<tr>
{% for widget in widget.subwidgets %}
<td>{% include widget.template_name %}</td>
{% endfor %}
</tr>
</tbody>
</table>
</div>
{% endspaceless %}
</code></pre>
| 0non-cybersec
| Stackexchange |
How to set all elements of an array to zero or any same value?. <p>I'm beginner in <strong>C</strong> and I really need an efficient method to set all elements of an array equal zero or any same value. My array is too long, so I don't want to do it with for loop.</p>
| 0non-cybersec
| Stackexchange |
Aurangabad Tour Packages. | 0non-cybersec
| Reddit |
I am looking for a old horror movie.. I watched a horror movie when I was younger,and I can't remember the name,I do remember a particulary scene where a girl ties up a guy and pours hot wax over his junk,then the girl goes down and there is nobody in the house,just a guy with a porcelain head..that's all I remember,pleaase help,TY. | 0non-cybersec
| Reddit |
My repaired Switch came back with a new app on it.... | 0non-cybersec
| Reddit |
django: TypeError: 'tuple' object is not callable. <p>Getting a type error, 'tuple' object is not callable. Any idea what it could be? (dont worry about the indentation. It copies in weird.) I'm trying to create choices based on PackSize of storeliquor.</p>
<p>Views.py:</p>
<pre><code>def storeliquor(request, store_id, liquor_id):
a = StoreLiquor.objects.get(StoreLiquorID=liquor_id)
s = Store.objects.get(StoreID=store_id)
x = Order.objects.get(storeID=s, Active=True)
y = a.OffPremisePrice
c = a.BottleSize
g = request.POST.get('OrderAmount', '')
b = a.PackSize
h = b*2
d = b*3
e = b*4
r = b*5
if c == "1750 ML":
pack_size = (
('1', '1')
('3', '3')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)
elif c == "1000 ML":
pack_size = (
('1', '1')
('3', '3')
('6', '6')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)
elif c == "750 ML":
pack_size = (
('1', '1')
('3', '3')
('6', '6')
(b, b)
(h, h)
(c, d)
(e, e)
(r, r)
)
elif c == "375 ML":
pack_size = (
('3', '3')
('6', '6')
('12', '12')
(b, b)
(h, h)
(d, d)
(e, e)
(r, r)
)
elif c == "200 ML":
pack_size = (
('12', '24')
('24', '24')
(b, b)
(c, c)
(c, d)
(e, e)
(r, r)
)
else:
pack_size = (
(b, b)
(c, c)
(c, d)
(e, e)
(r, r)
)
if request.method == "POST":
f = AddToOrderForm(request.POST)
if f.is_valid():
z = f.save(commit=False)
z.TotalPrice = (float(y)) * (float(g))
z.storeliquorID = a
z.orderID = x
z.save()
return HttpResponseRedirect('/stores/get/%s' % store_id)
else:
f = AddToOrderForm()
f.fields['OrderAmount'].choices = pack_size
args = {}
args['liquor'] = a
args['s'] = s
args['form'] = f
return render(request,'storeliquor.html', args)
</code></pre>
<p>Models file:</p>
<pre><code>class LiquorOrder(models.Model):
LiquorOrderID = models.AutoField(primary_key=True)
storeliquorID = models.ForeignKey(StoreLiquor)
orderID = models.ForeignKey(Order)
OrderAmount = models.CharField('Order Amount', max_length=3)
TotalPrice = models.DecimalField('Total Price', max_digits=5, decimal_places=2)
StorePrice = models.DecimalField('Store Price', max_digits=5, decimal_places=2)
</code></pre>
<p>Forms file:</p>
<pre><code>class AddToOrderForm(forms.ModelForm):
class Meta:
model = LiquorOrder
fields = ('OrderAmount', 'StorePrice')
</code></pre>
| 0non-cybersec
| Stackexchange |
Goodnight kiss. | 0non-cybersec
| Reddit |
I couldn’t relate to this any more. | 0non-cybersec
| Reddit |
PHP/JS software copy protection. <p>First of all I know nothing I can do that 100% prevents illegal copying of my software. I'd like to just make it reasonably hard for a competent person to do, and almost impossible for an unknowledgeable person to do.</p>
<p>I have a contract job coming up to develop a web app using the WAMP stack, commissioned by a company's IT manager. During our meeting and conversations, he kept being generic about the software requirements, seemingly refusing to develop requirements specific to his company. So I got the impression as if he was intending to resell the software to other companies for his profit.</p>
<p>And for people who say "people who pirate software aren't in your target market anyway", obviously that doesn't apply in this case because if he resells my software to other companies, those companies ARE in my target market.</p>
<p>The functionality in my software will be divided both in the server-side (PHP) and client-side (JS) using a good JS framework, if possible I want to protect both, (but I think for JS the only thing I can do is obfuscate the code).</p>
<p>I can't just refuse the contract because I need the money.</p>
<p>Is there anything at all I can do?</p>
<p>Edit: I'm also open to using external applications (i.e. written in C, Java, etc. or compiled into dll) to handle the copy-protection. Just need to know the general mechanism of it, if possible.</p>
| 0non-cybersec
| Stackexchange |
Eyesight of Bangladesh . | 0non-cybersec
| Reddit |
Sloth. In a formal gown. Shopping at an art store. Her name is Soleil.. | 0non-cybersec
| Reddit |
What Did You Play This Week? (Aug 26 - Sept 1). Happy Monday, /r/boardgames!
It's time to hear what games everyone has been playing for the past ~7 days. Please feel free to share any insights, anecdotes, or thoughts that may have arisen during the course of play. Also, don't forget to comment and discuss other peoples' games too.
Weekly Question: How much do you tolerate 'puzzling through the rules' play? | 0non-cybersec
| Reddit |
Fixed Microphone not working on Huawei nova 3 2 2018. | 0non-cybersec
| Reddit |
If your identical twin got plastic surgery, it would be hard not to feel a little insulted. | 0non-cybersec
| Reddit |
I love the county police's daily call log. | 0non-cybersec
| Reddit |
vb.Net TabControl best practise. In wondering if I'm going about something the right way. I need to represent many instances of a 'config', so I have a form that repopulates whenever a new tab is selected. You add tabs to create new configs and save them.
My solution at the moment is to give the TabPage.Text property the config.id value. This is a crap solution. I wish there was a TabPage.value like combo boxes have.
What's the best way to associate each tab with a config. The config is essentially a record in a SQL database. | 0non-cybersec
| Reddit |
rails 4 strong params + dynamic hstore keys. <p>I'm having a problem overcoming the new strong params requirement in Rails 4 using Hstore and dynamic accessors</p>
<p>I have an Hstore column called <code>:content</code> which I want to use to store content in multiple languages, ie <code>:en, :fr</code>, etc. And I don't know which language upfront to set them in either the model or the controller.</p>
<pre><code>store_accessor :content, [:en, :fr] #+226 random other il8n languages won't work.
</code></pre>
<p>How can I override strong params (or allow for dynamic hstore keys) in rails 4 for one column?</p>
<pre><code> params.require(:article).permit(
:name, :content,
:en, :fr #+226 random translations
)
</code></pre>
<p>Short of...</p>
<pre><code>params.require(:article).permit!
</code></pre>
<p>which of course does work.</p>
| 0non-cybersec
| Stackexchange |
When you show cleavage, do you want men to look or not?. | 0non-cybersec
| Reddit |
GeoDjango can't find geos library. <p>When attempting to fire up the django server, I get the following error:</p>
<pre><code>django.core.exceptions.ImproperlyConfigured: Could not import user-defined GEOMETRY_BACKEND "geos".
</code></pre>
<p>I'm running postgresql8.4 on Mac OS Lion.</p>
<p>I've used Macports to install PostGIS. Here's what $ port installed shows:</p>
<p>postgis @1.5.2_1+postgresql84
postgis @1.5.2_1+postgresql90
postgis @1.5.3_0+postgresql90
postgis @1.5.3_0+postgresql91 (active)</p>
<p>Here's what I get when attempting to determine what version of PostGIS I've got:</p>
<pre><code>geodjango=# SELECT PostGIS_full_version();
ERROR: could not access file "$libdir/postgis-1.5": No such file or directory
CONTEXT: SQL statement "SELECT postgis_lib_version()"
PL/pgSQL function "postgis_full_version" line 11 at SQL statement
</code></pre>
| 0non-cybersec
| Stackexchange |
How to select elements row-wise from a NumPy array?. <p>I have an array like this numpy array</p>
<pre><code>dd= [[foo 0.567 0.611]
[bar 0.469 0.479]
[noo 0.220 0.269]
[tar 0.480 0.508]
[boo 0.324 0.324]]
</code></pre>
<p>How would one loop through array
selecting foo and getting 0.567 0.611 as floats as a singleton.
Then select bar and getting 0.469 0.479 as floats as a singleton .....</p>
<p>I could get vector the first elements as list by using </p>
<pre><code>dv= dd[:,1]
</code></pre>
<p>The 'foo', and 'bar' elements are not unknown variables, they can change. </p>
<p>How would I change if element is in position [1]?</p>
<pre><code>[[0.567 foo2 0.611]
[0.469 bar2 0.479]
[0.220 noo2 0.269]
[0.480 tar2 0.508]
[0.324 boo2 0.324]]
</code></pre>
| 0non-cybersec
| Stackexchange |
Change the name of my user drive?. <p>I used to have two drives on my machine, Fast and Big. I replaced Big with Bigger. Now there are a number of pointers in various apps that still point to Big.</p>
<p>Is there a way to rename my new drive to be Big? It's my user drive, so it won't let me do it in the obvious way using Get Info.</p>
| 0non-cybersec
| Stackexchange |
Nashville carjacking foiled by manual transmission. | 0non-cybersec
| Reddit |
Electrical Services Middleburg Florida | 904-458-5577 | 24/7 Local Emergency Electrical Services Middleburg Florida. | 0non-cybersec
| Reddit |
Powershell query lastlogondate (lastlogontimestamp) returning mostly blank values (not matching the ADSIedit value for corresponding user attribute). <p>I am running a very short script to simply print out all users and their last logon time:</p>
<p>get-aduser -filter * -property * |ft name, lastlogondate</p>
<p>I noticed only a small handful of users have a logon date value while the vast majority it is blank. These are active users logging in every day. It is my understanding that lastlogondate is some sort of powershell alias that converts the 'lastlogontimestamp' user attribute value from a large integer into a readable date. I had success with this query in the past and again it works fine for some users. I went into ADSIedit and found that all users have a value in lastlogontimestamp. Despite this, if I directly query that value I still get blank in PS for each user in question:</p>
<p>get-aduser -filter * -property * |ft name, lastlogontimestamp</p>
<p>This behavior is true on all 3 DCs in the domain. I am baffled. This is part of a larger script that reports and acts on user accounts who haven't logged in longer than X days and has been running fine on a quarterly basis until today. In running it today I noticed that very few users were appearing on the report as being stale, so in troubleshooting I included the most basic query to see what it would do. The blank time stamp being returned in powershell is definitely wrong and why so few users show up on my report as stale (script excludes blank logon values), but I don't know why the value in PS is blank while the value in ADSI editor for the specific user is definitely populated. This is true of several other attributes like 'logoncount' as well, and only for those affected users (majority) while the few users that are working properly have no descrepencies between ADSI attribute and what PS shows at all. </p>
<p>All 3 DCs in this example are 2012 R2 and I noticed this behavior also happens on user accounts in a smaller mixed domain we have (2008 and 2012 DCs) but went unnoticed because hardly any users reside there so it isn't that much of a focus.</p>
<p>One other important thing, if I run this PS command against computer accounts Get-ADcomputer instead of Get-ADuser I have no such issues, all Computers report a lastlogondate correctly with no blanks.</p>
<p>Any help before I call Microsoft?</p>
| 0non-cybersec
| Stackexchange |
How to use spot instance with amazon elastic beanstalk?. <p>I have one infra that use amazon elastic beanstalk to deploy my application.
I need to scale my app adding some spot instances that EB do not support.</p>
<p>So I create a second autoscaling from a launch configuration with spot instances.
The autoscaling use the same load balancer created by beanstalk.</p>
<p>To up instances with the last version of my app, I copy the user data from the original launch configuration (created with beanstalk) to the launch configuration with spot instances (created by me).</p>
<p>This work fine, but:</p>
<ol>
<li><p>how to update spot instances that have come up from the second autoscaling when the beanstalk update instances managed by him with a new version of the app?</p>
</li>
<li><p>is there another way so easy as, and elegant, to use spot instances and enjoy the benefits of beanstalk?</p>
</li>
</ol>
<p><strong>UPDATE</strong></p>
<p>Elastic Beanstalk add support to spot instance since 2019... see:
<a href="https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html</a></p>
| 0non-cybersec
| Stackexchange |
vueJS + webpack: importing fonts, CSS, and node_modules. <p>I'm starting with Vue.js and Webpack and I'm having some doubts about how to correctly import and reference my fonts, CSS, and <code>node_modules</code> correctly.</p>
<p>I started my application using <code>vue-cli</code>, and here's the resultant structure:</p>
<pre><code>build
config
node_modules
src
--assets
--components
--router
static
</code></pre>
<p>And here's my <code>webpack.base.conf</code> file:</p>
<pre><code>var path = require('path')
var utils = require('./utils')
var config = require('../config')
var vueLoaderConfig = require('./vue-loader.conf')
function resolve (dir) {
return path.join(__dirname, '..', dir)
}
module.exports = {
entry: {
app: './src/main.js'
},
output: {
path: config.build.assetsRoot,
filename: '[name].js',
publicPath: process.env.NODE_ENV === 'production'
? config.build.assetsPublicPath
: config.dev.assetsPublicPath
},
resolve: {
extensions: ['.js', '.vue', '.json'],
alias: {
'vue$': 'vue/dist/vue.esm.js',
'@': resolve('src')
}
},
module: {
rules: [
{
test: /\.(js|vue)$/,
loader: 'eslint-loader',
enforce: 'pre',
include: [resolve('src'), resolve('test')],
options: {
formatter: require('eslint-friendly-formatter')
}
},
{
test: /\.vue$/,
loader: 'vue-loader',
options: vueLoaderConfig
},
{
test: /\.js$/,
loader: 'babel-loader',
include: [resolve('src'), resolve('test')]
},
{
test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('img/[name].[hash:7].[ext]')
}
},
{
test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('fonts/[name].[hash:7].[ext]')
}
}
]
}
}
</code></pre>
<p>First of all, where is the correct place to put my custom CSS and images? I'm currently putting them inside <code>assets/css</code> and <code>assets/img</code>, respectively (I created these folders). Is it correct?</p>
<p>I also have some CSS and fonts from external libraries (Bootstrap and Font Awesome, for example) that I have installed via NPM. They're located at <code>node_modules</code>.</p>
<p>If I'm not wrong, Webpack transforms, and copies these files to another location. How can I reference them on my Vue files and CSS files?</p>
<p>Using <code>import './assets/css/style.css'import '../node_modules/path/to/bootstrap.min.css'</code> works (at least in production), but should I be using another path?</p>
<p>Inside my custom CSS files, I reference some fonts from an external library using:</p>
<pre><code>src: url('/node_modules/roboto-fontface/fonts/Roboto/Roboto-LightItalic.eot')
</code></pre>
<p>The code compiles, but when I open the page in the browser, I receive a 404 error when searching for these fonts. How should I be referencing these fonts in my custom CSS?</p>
| 0non-cybersec
| Stackexchange |
Pretty cool graphic from Time magazine.. | 0non-cybersec
| Reddit |
[WP] Critiquecast call for submissions: brought the wrong one [x-post /r/shutupandwrite]. *x-posted from /r/shutupandwrite. Talk here if you wanna, but please submit to the [official thread](http://www.reddit.com/r/shutupandwrite/comments/1fj7hx/critiquecast_call_for_submissions_brought_the/).*
****
The Critiquecast is taking your stories again! Yes, finally. Yes, it's been two months. Yes, we're a little bit more on top of things now.
**What is [the Critiquecast](http://shutupandwrite.net/category/critiquecast/)?**
We are a group of amateur writers who got together and decided to critique others' writing on the air. It's not meant to be a serious critique (*amateur* writers, remember); it's more so to give you the experience of hearing your writing read aloud by an unforgiving and unfair audience.
For this cycle we will be picking **six** stories to critique on the air. How? You're going to tell us which ones, that's how. The official submission thread in /r/shutupandwrite will be put into Contest Mode for the duration of the week, and whatever ones you want to see critiqued, you can upvote. We have the ultimate say in which ones we will pick to critique, but highly upvoted stories will be given more consideration.
Recordings speak louder than words:
* [26. A Cut Below](http://shutupandwrite.net/2013/05/20/critiquecast-026-a-cut-below/)
* [14. People McNuggets](http://shutupandwrite.net/2013/04/01/critiquecast-14-people-mcnuggets/)
* [12. Breakfast with a Boner](http://shutupandwrite.net/2013/03/24/critiquecast-012-breakfast-with-a-boner/)
**THE PROMPT**
> The main character realizes that he/she brought the wrong one. No, that's not a typo. You're supposed to fill in the wrong *what* (or *who* or *whatever*) with your imagination.
**Submission guidelines**
* Maximum submission length: 1,200 words. Bonus points if you keep it to 1,000.
* Submissions must be in the form of a Google doc.
* Submissions *must* be on the /r/shutupandwrite thread, otherwise voting's going to be a headache for everyone involved.
* Submissions are due on MIDNIGHT EST, Sunday, June 9th.
**Voting guidelines**
Vote for whatever stories you'd like to see critiqued on the show! A few days after submissions end, we'll announce which six we're going to critique. Unfortunately that means we might be neglecting a few stories, so feel free to submit your own audio critiques as replies to the submitter. Anything that's well-done and in the style of the critiquecast (unprofessional and blatantly unfair) may be selected as a bonus episode to go up whenever we feel like it.
**Reddit Gold**
The arbitrarily selected "winner" of this cycle of the critiquecast will be awarded Reddit Gold. That's about all there is to it. Enjoy your glided comment, future winner! | 0non-cybersec
| Reddit |
How do I iterate over an entire MongoDB collection using mongojs?. <p>I'm using <code>mongojs</code> and I'm trying to iterate over all elements in a collection</p>
<pre><code>index = 0
db.keys.find({}, {uid: 1, _id: 0}).forEach((err, key) =>
if err?
console.log err
else
console.log (++index) + " key: " + key_uid
</code></pre>
<p>which logs</p>
<pre><code>1 key: bB0KN
2 key: LOtOL
3 key: 51xJM
4 key: x9wFP
5 key: hcJKP
6 key: QZxnE
.
.
.
96 key: EeW6E
97 key: wqfmM
98 key: LIGHK
99 key: bjWTI
100 key: 2zNGE
101 key: F71mL
</code></pre>
<p>and then stops. However when I log into mongo from the terminal and run</p>
<pre><code>> db.keys.count()
2317381
</code></pre>
<p>So clearly it should be returning a lot more keys. Do you have any ideas what could be causing this behavior? </p>
| 0non-cybersec
| Stackexchange |
How can we know the answer to 1-1+1-1+1...?. <p>I was watching this <a href="https://www.youtube.com/watch?v=P913qwtXihk" rel="nofollow">video</a> I noticed that the teacher said that 1-1+1-1+1... equals 1/2. How can we know that? The proof he uses doesn't make sense to me. We go from 1 to 0 to 1 and back again, etc. If it goes on like so forever, where does a fraction come into play?</p>
| 0non-cybersec
| Stackexchange |
How to determine asymptotics properties for estimators. <p>The question is as follows: If $X_i,\ldots,X_n$ are iid $N(\theta, \sigma^2)$, compare the asymptotic variance of the sample mean and sample median. </p>
<p>Attempt:</p>
<p>Would the asymptotic variance for the mean be the limit as $n$ approaches infinity of the quantity $\sigma^2/n$? Could we use the Cramer Rao Information bound as an approximation to the asymptotic variance? Also, does it matter what the parent distribution is? Wouldn't the asymptotic variance of the mean always be $\sigma^2/n$ due to the central limit theorem?</p>
| 0non-cybersec
| Stackexchange |
how to change /etc/environment from bash. <p>So I messed up. I was experimenting with path environment, and I accidentally edited the <code>/etc/environemnt</code> and added <code>PATH=$PATH:$JAVA_HOME/bin</code> and now I stucked on login loop.</p>
<p>I tried to fix my mistake by editing the <code>/etc/environment</code> from <code>ctrl+alt+f3</code> but I got `Permission denied.</p>
<p>I also tried to use <code>/bin/su</code> but again, I got error:</p>
<pre><code>bash: kesspipe: command not found
bash: dircolors: command not found
</code></pre>
<p>Is there a way to fix this? Thank you.</p>
| 0non-cybersec
| Stackexchange |
search sequence of sequences for single first match efficiently. <p>I want to figure out the single matching group.
As all groups are disjoint, only a single match is possible.
If no match is found <code>other</code> is returned.</p>
<p>A single match is enough. It is not efficient to search the whole sequence
How can the search be stopped after the first match?</p>
<p>How can this be written in a more scala-like/functional way which is less clumsy?</p>
<pre><code>val input = 1
val groupings = Seq(Seq(1), Seq(2, 4), Seq(6, 7))
def computeGroup(input: Int, groups: Seq[Seq[Int]]): String = {
val result = for (s <- groupings if (s.contains(input)))
yield s
val matchingGroup: Seq[Int] = result.flatten
if (matchingGroup.isEmpty) {
"other"
} else {
matchingGroup.mkString("-")
}
}
computeGroup(1, groupings) // expected 1
computeGroup(2, groupings) // expected 2-4
computeGroup(5, groupings) // expected other
</code></pre>
<p>Following the advice of <a href="https://stackoverflow.com/questions/16883591/find-the-first-element-that-satisfies-condition-x-in-a-seq">Find the first element that satisfies condition X in a Seq</a></p>
<pre><code>groupings.find(_ == Seq(input))
</code></pre>
<p>partially works for <code>computeGroup(1, groupings)</code>. It is already better as it should stop after the first match.</p>
<pre><code>Some(List(1))
None
None
</code></pre>
<p>Unfortunately, it will not (yet) handle the other cases.</p>
| 0non-cybersec
| Stackexchange |
A peacock I drew for an art class last year. | 0non-cybersec
| Reddit |
Database schema tracking patient stats over time. <p>I want to create a database which allows to record patient reading data points like: <em>weight</em>, <em>height</em>, <em>pressure</em>, etc., over time.</p>
<p>I found a database schema like the one discussed <a href="https://stackoverflow.com/questions/11216080/data-structure-for-storing-height-and-weight-etc-over-time-for-multiple-users">in this Q & A</a> which is looks similar to my needs. I'm wondering if such design offers a good performance for a large number of users?</p>
<p>For example, if we're planning to track 10 parameters for 10 000 users at least 20 times a year - it's around 2 000 000 rows/per year.</p>
<p>Available engine - InnodDB, MyISAM.</p>
<pre><code>DB healthstats
TABLE user
memberID (int*, auto increment, unsigned, primary key)
name (varchar, 50)
gender (char, 1)
birthdate (date)
TABLE reading
readingID (int*, auto increment, unsigned, primary key)
memberID (int*, FK: TABLE user)
date (datetime)
TABLE stat
statID (int*, auto increment, unsigned, primary key)
readingID (int*, FK: TABLE reading)
type (varchar, 3)*
value (decimal 4.1)*
</code></pre>
| 0non-cybersec
| Stackexchange |
Microsoft Word - MMT_Kanaan_Wenger_Chablat_review_2.doc
1
Kinematic Analysis of a Serial – Parallel Machine Tool: the VERNE machine
Daniel Kanaan, Philippe Wenger and Damien Chablat
Institut de Recherche en Communications et Cybernétique de Nantes UMR CNRS 6597
1, rue de la Noë, BP 92101, 44312 Nantes Cedex 03 France
E-mail address: [email protected]
Abstract
The paper derives the inverse and the forward kinematic equations of a serial – parallel 5-axis machine tool: the
VERNE machine. This machine is composed of a three-degree-of-freedom (DOF) parallel module and a two-DOF serial
tilting table. The parallel module consists of a moving platform that is connected to a fixed base by three non-identical
legs. These legs are connected in a way that the combined effects of the three legs lead to an over-constrained
mechanism with complex motion. This motion is defined as a simultaneous combination of rotation and translation. In
this paper we propose symbolical methods that able to calculate all kinematic solutions and identify the acceptable one
by adding analytical constraint on the disposition of legs of the parallel module.
Keywords: Parallel kinematic machines; Machine tool; Complex motion; Inverse kinematics; Forward kinematics.
1. Introduction
Parallel kinematic machines (PKM) are well known for their high structural rigidity, better payload-to-weight ratio, high
dynamic performances and high accuracy [1, 2, 3]. Thus, they are prudently considered as attractive alternatives designs
for demanding tasks such as high-speed machining [4]. Most of the existing PKM can be classified into two main
families. The PKM of the first family have fixed foot points and variable–length struts, while the PKM of the second
family have fixed length struts with moveable foot points gliding on fixed linear joints [5, 6].
In the first family, we distinguish between PKM with six degrees of freedom generally called Hexapods and PKM with
three degrees of freedom called Tripods [7, 8]. Hexapods have a Stewart–Gough parallel kinematic architecture. Many
prototypes and commercial hexapod PKM already exist, including the VARIAX (Gidding and Lewis), the TORNADO
2000 (Hexel). We can also find hybrid architectures such as the TRICEPT machine (SMT Tricept) [9], which is
composed of a two-axis wrist mounted in series to a 3-DOF “tripod” positioning structure.
In the second family, we find the HEXAGLIDE (ETH Zürich) that features six parallel and coplanar linear joints. The
HexaM (Toyoda) is another example with three pairs of adjacent linear joints lying on a vertical cone [10]. A hybrid
parallel/kinematic PKM with three inclined linear joints and a two-axis wrist is the GEORGE V (IFW Uni Hanover).
Many three-axis translational PKMs belong to this second family and use architecture close to the linear Delta robot
originally designed by Clavel for pick-and-place operations [11]. The Urane SX (Renault Automation) and the
QUICKSTEP (Krause and Mauser) have three non-coplanar horizontal linear joints [12].
Because many industrial tasks require less than six degrees of freedom, several lower-DOF PKMs have been developed
[13-15]. For some of these PKMs, the reduction of the number of DOFs can result in coupled motions of the mobile
platform. This is the case, for example, in the RPS manipulator [13] and in the parallel module of the Verne machine.
The kinematic modeling of these PKMs must be done case by case according to their structure.
Many researchers have contributed to the study of the kinematics of lower-DOF PKMs. Many of them have focused on
2
the discussion of both analytical and numerical methods [16, 17]. This paper investigates the inverse and direct
kinematics of the VERNE machine and derives closed form solutions. The VERNE machine is a 5-axis machine-tool
that was designed by Fatronik for IRCCyN [18, 19]. This machine-tool consists of a parallel module and a tilting table
as shown in Fig. 1. The parallel module moves the spindle mostly in translation while the tilting table is used to rotate
the workpiece about two orthogonal axes.
The purpose of this paper is to formulate analytic expressions in order to find all possible solutions for the inverse and
forward kinematics problem of the VERNE machine. Then we identify and sort these solutions in order to find the one
that satisfies the end-user.
Figure 1: Overall view of the VERNE machine
The following section describes the VERNE machine. In section 3, we study the kinematics of the parallel module of
the VERNE machine. In section 4 the methods presented in section 3 are extended to study the kinematic of the full
VERNE machine. Finally Section 5 concludes this paper.
2. Description of the VERNE machine
The VERNE machine consists of a parallel module and a tilting table as shown in Fig. 2. The vertices of the moving
platform of the parallel module are connected to a fixed-base plate through three legs Ι, ΙΙ and ΙΙΙ. Each leg uses a pair of
rods linking a prismatic joint to the moving platform through two pairs of spherical joints. Legs ΙΙ and ΙΙΙ are two
identical parallelograms. Leg Ι differs from the other two legs in that it is a trapezium instead of a parallelogram,
namely, 11 12 11 12A A B B≠ , where ijA (respectively ijB ) is the center of spherical joint number j on the prismatic joint
number i (respectively on the moving platform side), i = 1..3, j = 1..2. The movement of the moving platform is
generated by three sliding actuators along three vertical guideways.
3
P
xp
yp
zp
ρ1
B11
A12
A21
A22
A32
A11
B12
B21
B22
B31
B32
x
yz
ΙΙΙ
Ι ΙΙ
ρ2
ρ3
α
A31
(a)
ΙΙ Ι
ΙΙΙ
x
y z
xpyp zp
xt
zt yt
da
dt
Tilting axis
Δ
U
(b)
Figure 2: Schematic representation of the VERNE machine; (a) simplified representation and (b) the real
representation supplied by Fatronik
Due to the arrangement of the links and joints, legs ΙΙ and ΙΙΙ prevent the platform from rotating about y and z axes. Leg
Ι prevents the platform from rotating about z-axis (Fig. 2). Because this leg is a trapezium ( 11 12 11 12A A B B≠ ), however, a
slight coupled rotation α about the x-axis exists as shown in Fig. 2a. As shown further on, this coupled rotation makes
the kinematic analysis more complex. Its impact on the workspace has not been fully investigated yet. The reasons why
Fatronik has equipped leg I with a trapezium rather than with a parallelogram like in conventional linear Delta machines
are beyond the authors’ knowledge.
The tilting table is used to rotate the workpiece about two orthogonal axes. The first one, the tilting axis, is horizontal
and the second one, the rotary axis, is always perpendicular to the tilting table.
This machine takes full advantage of these two additional axes to adjust the tool orientation with respect to the
workpiece.
3. Kinematic analysis of the parallel module of the VERNE machine
3.1 Kinematic equations
In order to analyze the kinematics of our parallel module, two relative coordinates are assigned as shown in Fig. 2a. A
static Cartesian frame ( , , , )bR O x y z= is fixed at the base of the machine tool, with the z-axis pointing downward
4
along the vertical direction. The mobile Cartesian frame, ( , , , )pl P P PR P x y z= , is attached to the moving platform at
point P.
In any constrained mechanical system, joints connecting bodies restrict their relative motion and impose constraints on
the generalized coordinates, geometric constraints are then formulated as algebraic expressions involving generalized
coordinates.
Let us b plT define the transformation matrix that brings the fixed Cartesian frame bR on the frame plR linked to the
moving platform.
( ) ( ), , , b pl p p pT Trans x y z Rot x α= (1)
We use this transformation matrix to express ijB as function of , , and p p px y z α by using the relation
b pl
ij pl ijB T B=
where pl ijB represents the point ijB expressed in the frame plR .
-600 -400 -200 0 200 400 600
-800
-600
-400
-200
0
200
400
600
800
P
A11
B11
A12B12
A21
B21
A22
B22
A31
B31
A32
B32
r4
y
x
yP
xP
R2
d2
D2
R1
D1
r1
d1
2r3
2r2
Figure 3: Dimensions of the parallel kinematic structure in the frame supplied by Fatronik
Using the parameters defined in Figs. 2 and 3, the constraint equations of the parallel manipulator are expressed as:
( ) ( ) ( ) ( )2 2 2 22 2 0 1..3, 1..2ij ij i Bij Aij Bij Aij Bij Aij iA B L x x y y z z L i j− = − + − + − − = = = (2)
Leg Ι is represented by two different Eqs. (3a-3b). This is due to the fact that 11 12 11 12A A B B≠ (figure 3).
( ) ( ) ( )2 2 2 21 1 1 1 1 1 1cos( ) sin( ) 0P P Px D d y R r z R Lα α ρ+ − + + − + + − − = (3a)
( ) ( ) ( )2 2 2 21 1 1 1 1 1 1cos( ) sin( ) 0P P Px D d y R r z R Lα α ρ+ − + − + + − − − = (3b)
Leg ΙΙ is represented by a single Eq. (4).
( ) ( ) ( )2 2 2 22 2 2 4 2 2 2cos( ) sin( ) - 0P P Px D d y R r z R Lα α ρ+ − + − + + − − = (4)
Leg ІІІ, which is similar to leg ІІ (figure 3), is also represented by a single Eq. (5).
( ) ( ) ( )2 2 2 22 2 2 4 2 3 3cos( ) sin( ) 0P P Px D d y R r z R Lα α ρ+ − + + − + + − − = (5)
3.2 Coupling between the position and the orientation of the platform
The parallel module of the VERNE machine possesses three actuators and three degrees of freedom. However, there is a
5
coupling between the position and the orientation angle of the platform. The object of this section is to study the
coupling constraint imposed by leg I.
By eliminating 1ρ from Eqs. (3a) and (3b), we obtain a relation (6) between , and P Px y α independently of Pz .
( ) ( ) ( )( )2 22 2 2 2 2 2 2 2 21 1 1 1 1 1 1 1 1 1 1 1 1sin ( ) 2 cos( ) sin ( ) 2 cos( ) 0P PR x D d r R r R y R L R r R rα α α α+ − + − + − − + − = (6)
We notice that for a given α , Eq. (6) represents an ellipse (7). The size of this ellipse is determined by a and b , where
a is the length of the semi major axis and b is the length of the semi minor axis.
( )2 21 1
2 2 1
P Px D d y
a b
+ −
+ = (7)
where
( )( )
( )( )
( )
2 2 2
1 1 1 1 1
2 2 2 2 2
1 1 1 1 1 1
2 2
1 1 1 1
2 cos( )
sin ( ) 2 cos( )
2 cos( )
a L R r R r
R L R r R r
b
r R r R
α
α α
α
⎧ = − + −⎪
⎪
⎨ − + −
⎪ =
⎪ − +⎩
These ellipses define the locus of points reachable with the same orientation .α
3.3 The Inverse kinematics
The inverse kinematics deals with the determination of the joint coordinates as function of the moving platform position.
For the inverse kinematic problem of our spatial parallel manipulator, the position coordinates ( , , P P Px y z ) are given
but the coordinates ( 1..3)i iρ = of the actuated prismatic joints and the orientation angle α of the moving platform are
unknown.
Figure 4: (a) Curves of iso-values of the orientation α from - to π π+ following a constant step of 2 / 45π (b)
zoom of the framed zone
To solve the inverse kinematic problem, we first find all the possible orientation angles α for prescribed values of the
position of the platform ( , , P P Px y z ). These orientations are determined by solving Eq. (8), a third-degree-characteristic
polynomial in cos( )α derived from Eq. (6).
3 21 2 3 4cos ( ) cos ( ) cos( ) 0p p p pα α α+ + + = (8)
where
( ) ( )
( ) ( ) ( )
3
1 1 1
22 2 2 2 2
2 1 1 1 1 1 1 1
3 2
3 1 1 1 1
22 2 2 2 2 2 2 2
4 1 1 1 1 1 1 1 1 1
2
2 2
P
P
P P
p R r
p R L R r R x D d
p R r R r y
p R x D d R r y R L R r
⎧ =
⎪
= − − − + −⎪⎪
⎨
= − −⎪
⎪
= + − + + − − −⎪⎩
6
As shown in subsection 3.2, this equation also represents ellipses of iso-values of α . So if we plot all ellipses together
by varying α from - to π π+ (figure 4), we notice that every point (defined by ,Px Py and Pz ) is obtained by the
intersection of two ellipses. Thus, each ellipse represents two opposite orientations so each point can have a maximum
of four different orientations. This conclusion is verified by the fact that we can only find four real solutions to the
polynomial (Table I).
, ,
0
P P P
P
x y z
y
⎧
⎨
≠⎩
{ }1 2 and α α α= ± ±
, ,
0
P P P
P
x y z
y
⎧
⎨
=⎩
{ }10, , α α π= ±
TABLE I: the possible orientations for a fixed position of the platform
After finding all the possible orientations, we use the equations derived in subsection 3.1 to calculate the joint
coordinates iρ for each orientation angle α . To make this task easier, we introduce two new points 1A and 1B as the
middle of 11 12A A and 11 12B B , respectively. The constraint equation of these two points is:
( ) ( ) ( )( )2 22 2 2 21 1 1 1 1 1 1 12 cos( ) 0P P Px D d y z L R r R rρ α+ − + + − − − + − = (9)
Then, for prescribed values of the position and orientation of the platform, the required actuator inputs can be directly
computed from equations (9), (4) and (5):
( )( ) ( )( )22 2 2 21 1 1 1 1 1 1 1 1 2 cos( )P P Pz s L R r R r x D d yρ α= + − + − − + − − (10)
( ) ( )( )2 222 2 2 2 2 2 2 4 sin( ) cos( )P P Pz R s L x D d y R rρ α α= − + − + − − − + (11)
( ) ( )( )2 223 2 3 3 2 2 2 4 sin( ) cos( )P P Pz R s L x D d y R rρ α α= + + − + − − + − (12)
where { }1 2 3, , 1s s s ∈ ± are the configuration indices defined as the signs of 1 Pzρ − , 2 2 sin( )Pz Rρ α− + ,
3 2 sin( )Pz Rρ α− − , respectively.
Subtracting equation (3a) from equation (3b), yields:
( ) ( )P 1 1 1 1 Py R cos( ) r =R sin( ) zα α ρ− − (13)
Eq. (13) implies that: ( ) ( ) ( )1 1 P1sgn sgn sin( ) sgn R cos( ) r sgn(y )pz α αρ = −−
This means that for prescribed values of the position and orientation of the platform, the joint coordinate 1ρ possesses
one solution, except when {0, }.α π= In this case 1s can take on both values +1 and –1. As a result 1ρ can take on two
values when {0, }.α π=
{ }0, α π= 1 1s = ±
1 1
p
cos( )
y 0 with 0
R rα
α
=⎧⎪
⎨ = ≠⎪⎩
1 pzρ =
others 1 1 or -1s = +
TABLE II. Solutions of the joint coordinate 1ρ according to the values of α
Observing equations (10), (11), (12), Table I and Table II, we conclude that there are four solutions for leg Ι and two
solutions for leg ΙΙ and ΙΙΙ. Thus there are sixteen inverse kinematic solutions for the parallel module (figure 5).
From the sixteen theoretical inverse kinematics solutions shown in figure 5, only one is used by the VERNE machine:
the one referred to as (m) in figure 5, which is characterized by the fact that each leg must have its slider attachment
7
points above the moving platform attachment points, i.e. 1is = − (remember that the z-axis is directed downward).
(a) (b) (c) (d)
(e) (f) (g) (h)
(i) (j) (k) (l)
(m) (n) (o) (p)
Figure 5: The sixteen solutions to the inverse kinematics problem when
-240 mm, -86 mm and 1000 mmP P Px y z= = =
For the remaining 15 solutions one of the sliders leaves its joint limits or the two rods of leg I cross. Most of these
solutions are characterized by the fact that at least one of the legs has its slider attachment points below the moving
platform attachment points. So only 1 2 3, , 1s s s = − in Eqs. (10-12) must be selected (remember that the z-axis is
directed downward). To prevent rod crossing, we also add a condition on the orientation of the moving platform. This
condition is 1 1cos( ) .R rα > Finally, we check the joint limits of the sliders as well as the serial singularities [15], [20].
For the VERNE parallel module, applying the above conditions will always yield a unique solution for practical
applications (solution (m) shown in Fig. 5).
3.4 The forward kinematics
The forward kinematics deals with the determination of the moving platform position as function of the joint
coordinates. For the forward kinematics of our spatial parallel manipulator, the values of the joint coordinates
( 1..3)i iρ = are known and the goal is to find the coordinates Px , Py and Pz of the centre of the moving platform P.
8
To solve the forward kinematics, we eliminate successively Px , Py and Pz from the system ( 1)S of four equations
((3a), (3b), (4) and (5)) to have an equation function of the joint coordinates ( 1..3)i iρ = and function of the orientation
angle α of the platform. To do so, we first compute Py as function of Pz in Eq. (14) by subtracting Eq. (3a) from Eq.
(3b)
( )( )
( )( )
1 1
1 1
sin
cos
p
p
R z
y
R r
α ρ
α
−
=
−
(14)
The expression of py in Eq. (14) is substituted into system ( 1)S to obtain a new system ( 2)S of three Eqs. (15), (16)
and (17) derived from Eqs. (3a), (4) and (5) respectively.
( ) ( )( ) ( ) ( )( )
( ) ( )( ) ( ) ( )( )
2 23 3 2 2 2 2 2 2 2
1 1 1 1 1 1 1 1 1 1 1
2 2 22 2 2 2 2 2 2
1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 cos 5 cos
2 2 cos 0
p p
p p p
R r R x D d R r L R r z
R r x D d z R r L r x D d R r L
α α ρ
ρ α
+ + − + + − + + − −
+ − + − + + − + + − + + − =
(15)
( ) ( )( ) ( ) ( ) ( ) ( )( ) ( )
( ) ( ) ( )( )( ) ( )
( ) ( )( )( ) ( ) ( ) ( )
( )
1 1 4 1 2 1 1 2 1 2 1 2 1 4 1
2 2 2 2 2 2 2
1 1 2 1 1 2 2 4 2 2 4 1
2 22 2 2 2 2 2
2 1 4 1 1 2 2 2 2 4 2 1 2 2 1
22 2
1 1 1
2 2 cos sin 2 sin
4 cos
2 2 cos 2 ( )sin cos
p p p p
p p p
p p
p p
R R r z R r z r R r z R r z
R R x D d z z R r L R r r
R r r R r x D d z R r L R R
R z r x
ρ ρ ρ α α ρ ρ α
ρ ρ α
ρ α ρ ρ α α
ρ
− + − + + − − − +
+ − − − + − + + − + −
+ + − + − + + − + − +
− + ( ) ( )( ) ( )2 2 2 2 2 2 32 2 2 2 4 2 1 2 42 cos 0pD d z R r L R R rρ α+ − + − + + − − =
(16)
( ) ( )( ) ( ) ( ) ( ) ( )( ) ( )
( ) ( ) ( )( )( ) ( )
( ) ( )( )( ) ( ) ( ) ( )
( )
1 1 4 1 2 1 1 3 1 2 1 3 1 4 1
2 2 2 2 2 2 2
1 1 2 1 1 3 2 4 3 2 4 1
2 22 2 2 2 2 2
2 1 4 1 1 2 2 3 2 4 3 1 2 3 1
22 2
1 1 1
2 2 cos sin 2 sin
4 cos
2 2 cos 2 ( )sin cos
p p p p
p p p
p p
p
R R r z R r z r R r z R r z
R R x D d z z R r L R r r
R r r R r x D d z R r L R R
R z r
ρ ρ ρ α α ρ ρ α
ρ ρ α
ρ α ρ ρ α α
ρ
− − − − + + − − + − +
+ − − − + − + + − + −
+ + − + − + + − − − +
− + ( ) ( )( ) ( )2 2 2 2 2 2 32 2 3 2 4 3 1 2 42 cos 0p px D d z R r L R R rρ α+ − + − + + − − =
(17)
We then compute Pz as function of ( 1..3)i iρ = and α in Eq. (18) by subtracting equation (16) from equation (17).
( )( ) ( )( ) ( ) ( )( ) ( )( )
( ) ( )( )( )( )
1 1 2 3 3 2 2 3 2 1 1 1
1 1 1 3 2
cos 2 2 sin 4 sin
2 2 sin cos
p
R r R C
z
C R r
α ρ ρ ρ ρ ρ ρ ρ α ρ α
α α ρ ρ
− + − − + − +
=
+ − −
(18)
where ( )1 1 2 4 1C r R r R= −
The expression of pz in Eq. (18) is substituted into system ( 2)S to obtain a new system ( 3)S of two equations (19) and
(20) derived from equations (15) and (16) respectively. Finally, we compute Px as function of ( 1..3)i iρ = and α by
subtracting equation (19) from equation (20).
( ) ( )
( ) ( ) ( )( ) ( )( )( ) ( )( )( ) ( )
( ) ( )( ) ( ) ( )( ) ( )( )
( ) ( ) ( )( )( )
2
2 1 3 2
2 2
1 2 3 1 2 1 4 2 1 1 2 3 1 2 1 1 1
2
3 2 2 3 1 2 1 1 1 1 4 2 1 1
1 1 2 2 1 3 2 1 1
2 sin
2 4 cos 4 cos sin
2 2 cos cos
2( ) 2 sin cos
p
R C
C C r R rC R R r
C r r R r R R r
x
D d D d C R r
ρ ρ α
ρ ρ ρ ρ α ρ ρ ρ ρ α α
ρ ρ ρ ρ ρ ρ α α
α ρ ρ α
− − +
+ − + − − + + − − − +
− − − − − + − −
=
− − + + − −
(21)
where ( ) ( )2 2 2 2 2 2 2 22 2 2 1 1 1 4 1 2 1 3C D d D d r r R R L L= − − − + + − + + −
Then the above expression of px is substituted into system ( 3)S .
The resulting equations of system ( 3)S are given in Appendix A.
For each step, we determine solution existence conditions by studying the denominators that appear in the expressions
9
of Px , Py and Pz . These conditions are:
( )1 1cos 0R rα − ≠ (22)
( ) ( ) ( )( )1 3 2 1 12 sin cos 0C R rα ρ ρ α+ − − ≠ (23)
Equation (22) obtained from (13) implies that 1 1A B is perpendicular to the slider plane of leg І. In this case equation (7)
represents a circle because a b= .
When 2 3= ρ ρ in equation (23), we have {0, }α π= . This means that 0Py = (obtained from Equations. (4) − (5)).
To finish the resolution of the system, we perform the tangent-half-angle substitution tan( / 2)t α= . As a consequence,
the forward kinematics of our parallel manipulator results in a eight-degree-characteristic polynomial in t , whose
coefficients are relatively large expressions in 1ρ , 2ρ and 3ρ . Expressions of these coefficients are not reported here
because of space limitation. They are available in [20]. Knowing the value of α , we calculate , and p p px y z using Eqs
(21), (14) and (18), respectively. For the VERNE machine, only 4 assembly-modes have been found (figure 6). It was
possible to find up to 6 assembly-modes but only for input joint values out of the reachable joint space of the machine.
(a) (b)
(c) (d)
Figure 6: The four assembly-modes of the VERNE parallel module for 1 674 mm,ρ = 2 685 mmρ = and
3 250 mm.ρ = only (a) is reachable by the actual machine
10
Only one assembly-mode is actually reachable by the machine (solution (a) shown in Fig. 6) because the other ones lead
to either rod crossing, collisions, or joint limit violation. The right assembly mode can be recognized, like for the right
working mode, by the fact that each leg must have its slider attachment points above the moving platform attachment
points, i.e. 1is = − (keep in mind that the z-axis is directed downwards).
The proposed method for calculating the various solutions of the forward kinematic problem has been implemented in
Maple. Table III give the solutions for 1 674 mm,ρ = 2 685 mmρ = , 3 250 mmρ = and Fig. 6 shows the four assembly
modes
1 674 mm,ρ = 2 685 mmρ = and 3 250 mmρ =
Case α (rd) Px (mm) Py (mm) Pz (mm)
(a) -0.22 -199.80 355.92 1242
(b) -0.14 298.35 -297.53 -120.22
(c) 1.81 -393.6 322.82 958.21
(d) 2.70 -115.62 -189.68 -0.26
TABLE III: the numerical results of the forward kinematic problem of the example where 1 674 mm,ρ =
2 685 mmρ = and 3 250 mmρ =
4. Kinematic analysis of the full VERNE machine (parallel module + tilting table)
4.1 Kinematic equations
θ1
φ2
θ2
φ1
Tilting axis
Tool
Figure 7: Draw of the tilting table: the tool orientation is defined by two angles ( 1φ , 2φ ) relative to frame tR
linked to the tilting table . The orientation angles ( 1θ , 2θ ) of the tilting table are defined relative to frame bR
fixed to the base of the VERNE machine
In order to analyze the kinematics of the VERNE machine, we define the following coordinate frame as shown below in
Table IV:
11
Transformation Axis Angles/Distance Input Frame Output Frame
Translation z ad ( , , , )bR O x y z 1 1 1 1 1( , , , )R O x y z
Rotation x1 1θ 1 1 1 1 1( , , , )R O x y z 2 2 2 2 2( , , , )R O x y z
Translation z2 td 2 2 2 2 2( , , , )R O x y z 3 3 3 3 3( , , , )R O x y z
Rotation x3 π 3 3 3 3 3( , , , )R O x y z 4 4 4 4 4( , , , )R O x y z
Rotation z4 2θ 4 4 4 4 4( , , , )R O x y z ( , , , )t t t tR t x y z
Translation ,tx ty , tz ux , uy , uz ( , , , )t t t tR t x y z 5 5 5 5 5( , , , )R O x y z
Rotation z5 2φ 5 5 5 5 5( , , , )R O x y z 6 6 6 6 6( , , , )R O x y z
Rotation x6 1π φ+ 6 6 6 6 6( , , , )R O x y z 7 7 7 7 7( , , , )R O x y z
Translation z7 −Δ 7 7 7 7 7( , , , )R O x y z ( , , , )pl p p pR P x y z
Table IV: Transformation matrices that bring the input frame on the output frame; where ux , uy and uz are the
coordinates of the tool centre point (TCP), U, in tR
Let b tT define the transformation matrix that brings the fixed Cartesian frame bR on the frame tR linked to the tilting
table.
1 1 2 3 4 2( , ) ( , ) ( , ) ( , ) ( , )
b
t a tT trans z d rot x trans z d rot x rot zθ π θ= (24)
Let t plT define the transformation matrix that brings the frame tR linked to the tilting table on the frame plR linked to
the moving platform.
5 2 6 1 7( , , ) ( , ) ( , ) ( , )
t
pl u u uT trans x y z rot z rot x trans zφ π φ= + −Δ (25)
We use transformation matrices from Eqs. (24) and (25) in order to express ijB as function of u 1 2 1, , , , , u ux y z φ φ θ and
2θ by using the relation where
b pl b b t
ij pl ij pl t plB T B T T T= = and
pl
ijB represent the point ijB expressed in the frame plR .
Using Eq. (2) from section 3.1 and the parameters defined in Figs. 2 and 3, we can express all constraint equations of the
VERNE machine. However knowing that 1 1 2 2and are parallel for i=1..2i i i iA B A B , we can prove that
2 2θ φ= − (26)
Substituting the above value of 2θ in all constraint equations resulting from Eq. (2), we obtain that leg Ι is represented
by two different equations (27a) and (27b) while leg ΙΙ (respectively leg ΙΙΙ) is represented by only one equation (28)
(respectively equation (29)).
( )
( ) ( )( )
( ) ( )( )
2
2 2 1 1
2
1 1 2 2 1 1 1 1 1 1
2 2
1 2 2 1 1 1 1 1 1 1 1
cos( ) sin( )
sin( ) cos( ) sin( ) cos( ) sin( ) cos( )
sin( ) sin( ) cos( ) cos( ) cos( ) sin( ) 0
u u
u t u u
u u u t a
x y D d
z d x y R r
x y z d d R L
φ φ
θ θ φ φ θ φ θ φ
θ φ φ θ θ φ θ φ ρ
+ + − +
− + − + Δ + + + − +
− − − + − Δ + + + − − =
(27a)
( )
( ) ( )( )
( ) ( )( )
2
2 2 1 1
2
1 1 2 2 1 1 1 1 1 1
2 2
1 2 2 1 1 1 1 1 1 1 1
cos( ) sin( )
sin( ) cos( ) sin( ) cos( ) sin( ) cos( )
sin( ) sin( ) cos( ) cos( ) cos( ) sin( ) 0
u u
u t u u
u u u t a
x y D d
z d x y R r
x y z d d R L
φ φ
θ θ φ φ θ φ θ φ
θ φ φ θ θ φ θ φ ρ
+ + − +
− + − + Δ + − + + +
− − − + −Δ + − + − − =
(27b)
( )
( ) ( )( )
( ) ( )( )
2
2 2 2 2
2
1 1 2 2 1 1 2 1 1 4
2 2
1 2 2 1 1 1 2 1 1 2 2
cos( ) sin( )
sin( ) cos( ) sin( ) cos( ) sin( ) cos( )
sin( ) sin( ) cos( ) cos( ) cos( ) sin( ) 0
u u
u t u u
u u u t a
x y D d
z d x y R r
x y z d d R L
φ φ
θ θ φ φ θ φ θ φ
θ φ φ θ θ φ θ φ ρ
+ + − +
− + − + Δ + − + + +
− − − + − Δ + − + − − =
(28)
12
( )
( ) ( )( )
( ) ( )( )
2
2 2 2 2
2
1 1 2 2 1 1 2 1 1 4
2 2
1 2 2 1 1 1 2 1 1 3 3
cos( ) sin( )
sin( ) cos( ) sin( ) cos( ) sin( ) cos( )
sin( ) sin( ) cos( ) cos( ) cos( ) sin( ) 0
u u
u t u u
u u u t a
x y D d
z d x y R r
x y z d d R L
φ φ
θ θ φ φ θ φ θ φ
θ φ φ θ θ φ θ φ ρ
+ + − +
− + − + Δ + + + − +
− − − + − Δ + + + − − =
(29)
Identification of Eqs. (27a), (27b), (28) and (29) with Eqs. (3a), (3b), (4) and (5) respectively, yields :
1 1α θ φ= + (30)
Condition (30) will help us understand the behavior of the VERNE machine from the one already studied in section 3
for its parallel module.
4.2 The inverse kinematics
For the inverse kinematic problem of the VERNE machine, the position of the TCP ( , , u u ux y z ) and the orientation of
the tool ( 1 2 and φ φ ) are given relative to frame tR , but the joint coordinates, defined by the position ( 1..3)i iρ = of the
actuated prismatic and the orientation ( 1 2 and θ θ ) of the tilting table in the base frame bR are unknown.
Knowing that 2 2θ φ= − from (26), the problem consists in solving the system ( 4)S of 4 equations ((27a), (27b), (28)
and (29)) for only 4 unknowns ( ( 1..3)i iρ = and 1θ ).
To solve the inverse kinematics, we follow the same reasoning as in subsection 3.3. First, we eliminate 1ρ from Eqs.
(27a) and (27b) in order to obtain a relation (31) between the TCP position and orientation ( 1 2, , , and u u ux y z φ φ ) and
the tilting angle 1θ .
( )
( ) ( ) ( )( )
( )( )
22 2
1 1 1 2 2 1 1
22 2
1 1 1 1 1 1 1 1 2 2 1 1
2 2 2 2 2
1 1 1 1 1 1 1 1 1 1
sin ( ) cos( ) sin( )
2 cos( ) sin( ) cos( ) sin( ) cos( ) sin( )
sin ( ) 2 cos( ) 0
u u
u t u u
R x y D d
r R r R z d x y
R L R r R r
θ φ φ φ
θ φ θ θ φ φ θ φ
θ φ θ φ
+ + + − +
− + + − + − + Δ + −
+ − + − + =
(31)
Then, we find all possible orientation angles 1θ for prescribed values of the position and the orientation of the tool.
These orientations are determined by solving a six-degree-characteristic polynomial in 1tan( / 2)θ derived from Eq. (31).
This polynomial can have up to four real solutions. This conclusion is verified by the fact that 1 1θ φ α= − from Eq. 30
where α can have only four real solutions as proved in subsection 3.3. After finding all the possible orientations, we
use the system of equations ( 4)S in order to calculate the joint coordinates iρ for each orientation angle 1θ .
For 1,ρ we must verify that the values of 1ρ obtained from Eqs. (27a) and (27b) are the same, as a result, we eliminate
one of the two solutions.
Observing the above remark and equations (27a-27b), (28), (29) defined as two-degree-polynomials in , 1..3i iρ =
respectively, we conclude that there are four solutions for leg Ι and two solutions for leg ΙΙ and ΙΙΙ. Thus there are
sixteen inverse kinematic solutions for the VERNE machine.
As above, from the sixteen theoretical inverse kinematics solutions, only one is used by the VERNE machine. This
solution is characterized by the fact that each leg must have its slider attachment points above the moving platform
attachment points.
For the remaining 15 solutions one of the sliders leaves its joint limits or the two rods of leg I cross. Most of these
solutions are characterized by the fact that at least one of the legs has its slider attachment points lower than the moving
platform attachment points. To prevent rod crossing, we also add a condition on the orientation of the moving platform.
This condition is 1 1 1 1cos( ) .R rθ φ+ > Finally, we check the joint limits of the sliders and the serial singularities [15].
As already mentioned, applying the above conditions will always yield to a unique solution for practical applications.
13
4.3 The forward kinematics
For the forward kinematics of the VERNE machine, the values of the joint coordinates, defined by the position
( 1..3)i iρ = of the actuated prismatic and the orientation ( 1 2and θ θ ) of the tilting table in the base frame bR are known
and the goal is to find the position of the TCP ( , , u u ux y z ) and the orientation of the tool ( 1 2 and φ φ ) in the frame tR .
Knowing that 2 2φ θ= − from (26) and 1 1φ α θ= − from (30), we solve this problem by first solving the forward
kinematics of the parallel module of the VERNE machine in order to find the coordinates Px , Py and Pz of the centre
of the moving platform P and the orientation α of the moving platform in term of the joint coordinates ( 1..3)i iρ = .
We then use transformation matrices from Eqs. (1) and (24) in order to express the tool position and orientation
( 1 2, , , and u u ux y z φ φ ) as function of ( )1 2, , , ,P P Px y z θ θ .
1t t b t b pl b plb b pl t plU T U T T U T T U
−= = = (32)
where [ ]0 0 1 TplU = Δ and [ ]1 Tt u u uU x y z= represent the TCP, ,U expressed in frames plR (linked to the
moving platform) and the base frame bR respectively. Finally we obtain:
( )( )
( )( )
1 1
2 2
2 2 1 1 1
2 2 1 1 1
1 1 1 1
cos( ) sin( ) sin( ) cos( ) sin( )
sin( ) cos( ) sin( ) cos( ) sin( )
sin( ) cos( ) cos( ) cos( )
u p p p a
u p p p a
u p p a t
x x y z d
y x y z d
z y z d d
φ α θ
φ θ
θ θ α θ θ θ
θ θ α θ θ θ
θ θ θ α θ
⎧
= −⎪
⎪ = −
⎪⎪
= + Δ − − − −⎨
⎪
⎪ = − + Δ − − − −
⎪
= − + − Δ − +⎪⎩
(33)
The VERNE machine behaves like its parallel module, so only 4 assembly-modes is found (figure 6) and only one
assembly-mode is actually reachable by the machine (solution (a) shown in Fig. 6).
The proposed method for calculating the various solutions of the forward kinematic problem has been implemented in
Maple. Table V give the solution for 1 674 mm,ρ = 2 685 mmρ = , 3 250 mmρ = , 1 0.19 rdθ = and 2 0.39 rdθ = , the
corresponding assembly modes for the parallel module were shown in Fig. 6.
1 674 mm,ρ = 2 685 mmρ = , 3 250 mmρ = , 1 0.19 rdθ = and 2 0.39 rdθ =
Case 1φ rd 2φ rd ux (mm) uy (mm) uz (mm)
(a) -0.41 -0.39 -338.06 -296.89 461.6
(b) -0.33 -0.39 478.52 379.38 1661.55
(c) 1.62 -0.39 -22106. 497.49 1213.31
(d) 2.51 -0.39 219.2 837.37 2433.67
TABLE V: the numerical results of the forward kinematic problem of the example where 1 674 mm,ρ =
2 685 mmρ = , 3 250 mmρ = , 1 0.19 rdθ = and 2 0.39 rdθ =
5. Conclusion
This paper was devoted to the kinematic analysis of a 5-DOF hybrid machine tool, the VERNE machine. This machine
possesses a complex motion caused by the unsymmetrical architecture of the parallel module where one of the legs is
different from the other two legs. The inverse kinematics and the different assembly modes were derived. The forward
kinematics was solved with the substitution method. It was shown that the inverse kinematics has sixteen solutions and
the forward kinematics may have six real solutions. Examples were provided to illustrate the results. The special
geometry of one of the legs highly complicates the kinematic models. Because two of the opposite sides of this leg have
different lengths, the leg does not remain planar (rod directions define skew lines) as the machine moves, unlike what
14
arises in the other two legs that are articulated parallelograms. As a result, a coupling angle of the moving platform
about the x-axis exists. The derivation of the inverse and forward kinematic equations was not a trivial task and required
much effort. This work is of interest as it may improve the control of the machine. It is worth noting that the VERNE
machine is currently used every day for machining complex parts, especially for the molding industry. It is thus
important to try to improve the efficiency of the machine. The controller of the actual VERNE machine resorts to an
iterative Newton-Raphson resolution of the kinematic models. A fully comparative study between the symbolic and the
iterative approach is still in progress and will be presented in forthcoming publications. It is expected that the symbolic
method could decrease the Cpu-time and improve the quality of the control. The symbolic equations derived in this
work are currently implemented in a simulation package of PKMs.
6. Appendix A
( )( ) ( )( ) ( )( ) ( )( ) ( )
( )( ) ( ) ( )
( ) ( )( ) ( )( )( )(
( ) ( )
2 2 22 2 2 3
1 1 2 1 3 2 2 2 1 3 2 2 1 1 2 4 1
2 2
1 1 3 2 4 1 1 2
22 2 2 2 2 2 2 2 2 2 4 2 2 2
3 2 1 1 1 1 1 2 1 1 2 1 1 1 2 2 1 3 2 1 1
2 2 3
1 1 1 2 4 1 4 2 1 1
8 4 4 cos
32 cos sin
4 5 16
16 16 2
p
p
r R R R R r R r R
r R r R r R
x D d R R r R r R R R L R R r R
x D d r R r R r R R r
ρ ρ ρ ρ ρ ρ ρ ρ α
ρ ρ α α
ρ ρ ρ ρ ρ ρ
− − − − − + − + − +
− − +
− + − + − − − + − − − + −
+ − − + −( ) ( )( )
( )( ) ( )) ( )
( ) ( )( ) ( ) ( )( )( ) ( ) ( )
( ) ( ) ( ) ( ) ( ) ( )
22 2 2 2 2
1 1 1 1 1 2 2 1 1
22 2 2 2 2 2 2 2 2 2
1 2 2 1 1 1 1 4 1 1 1
22 2 2 2
1 3 2 1 2 3 2 1 1 2 4 1 1 1 1 1 1
24 3 2 2 2
1 1 3 2 3 2 2 1 3 2 2 1 1 1 1
2 2 16
16 16 cos
8 2 2 6 2 2 cos sin
2 4 4 2
p
p
r L r R R R r
r R r L R r r R L
R r R r R r R x D d r R L
r R x D d r
ρ ρ
ρ ρ α
ρ ρ ρ ρ ρ α α
ρ ρ ρ ρ ρ ρ ρ ρ ρ ρ
+ − − + −
− + − − + − +
− + − + − + − + + − −
− + − − + − − + + − +( )(
( )( ) ( )( )( )) ( )
( ) ( ) ( ) ( ) ( )( )( )( )(
( ) ( )( )) ( )
( ) ( ) ( ) ( )( ) ( )
2 2 2
1 2 1
22 2 2 2 2
2 3 2 1 2 2 2 1 1 1 4 1 1 2 4
2 22 2
3 2 2 1 1 3 2 2 1 3 2 2 1
2 2 2 2
1 4 1 1 2 1 1 1 1 1
2 2 22 2 2 2 2
2 1 2 3 2 1 1 2 1 3 2 2 3 2 1
16 16 2 cos
4 4
4 sin
4 (4 ) 4 (4 )
p
R R L
R R r R r r R R r
R R r
r r R r R x D d R r L
R R r R R
ρ ρ ρ ρ ρ ρ α
ρ ρ ρ ρ ρ ρ ρ ρ ρ ρ
α
ρ ρ ρ ρ ρ ρ ρ ρ ρ ρ
+ + − −
− − + − + + − −
− + − + − + − − −
− + − + + − +
− + − + + − − + − ( )
( )( ) ( )
( )( )( )
2
1
242 2 2 2 2 2
1 1 3 2 1 4 1 2 1 1 1 1 1
22 2 2 2 2 2 2
1 1 1 1 1 2 1 2 1
16( ) ( )
4 0
p
p
r
R r R r r R r x D d L R
r x D d r R R L R R
ρ ρ
+ +
+ − + − + + + − − + +
+ − + + + − + =
(19)
15
( )( ) ( ) ( )( )( ) ( )( ) ( )
( ) ( ) ( )( )( )( ) ( ) ( )
( )( ) ( ) ( )( )( )( )
2 2 22 3
2 1 2 1 1 4 3 2 4 1 2 1 3 2 2 1 4 1 2 4 1
22 2 2 2 2 2
2 3 2 1 2 1 3 2 2 1 1 4 1 2 1 1 2 4
23 2 22 2 2 2 2 2
1 2 1 3 2 1 2 2 2 1 4 3 1 4 1 2 1 2 3 2
16 2 2 cos
16 3 4 cos sin
4 10 5p
R R R r R r r R r r R r R
R R R r r R r R R r
R R x D d r L r r R R r R
ρ ρ ρ ρ ρ ρ ρ ρ α
ρ ρ ρ ρ ρ ρ ρ ρ α α
ρ ρ ρ ρ ρ ρ ρ ρ
− − + − + − − + − +
− − + − − + + − +
⎛− − − + + − − − − − + − − −
( ) ( )( ) ( )( ) ( )( )( ) ) ( )
( ) ( )( ) ( ) ( )( )( ) ( ) ( )
( )( )
22 22 2 2 2 2 2 2
1 4 2 2 1 3 2 2 1 2 2 4 2 3 1 2 1 4
22 2 2 2
3 2 1 2 1 4 1 3 2 1 2 1 1 2 2 4 2 3 1 4 2
22 2 2 2 2 2
4 2 1 2 1 1 2 4 1 1 4 1 2 4 1 2
4 4 cos
4 3 4 4 2 cos sin
32 2 32
p
p
R r R x D d r R L r R R r
R R r r R r R R r R x D d r R L r r R
r R R r R r R r r R R r R R
ρ ρ ρ ρ ρ ρ α
ρ ρ ρ ρ α α
ρ ρ
⎜
⎝
+ − − − − − + − + + − − +
⎛ ⎞− − − + − + − + + − + +⎜ ⎟
⎝ ⎠
− − + + − − ( )( )(
( )( )( )( ) ( ) ( )
( )( ) ( )( )( )(
( )( ) ( )
2 1 3 2
2 2 42 2 2 2 2
1 1 2 2 2 4 3 1 2 4 1 2 4 3 2 1 1 3 2
2 22 2 2 2
1 1 4 1 2 2 2 2 1 2 1 1 2 1 4 1 2 1 4 4 1 2 1 3 3 2
22 2 2
2 1 2 1 3 2 1 4 1 1 2 1 2
8 3 2 cos
4 2 2 2 2( )(2 )
4 2
p
p
r R x D d R r L R R r r R r r R
r R r r R x D d R R r R R r r R r r r R R r L
R R r r R R R r R
ρ ρ ρ ρ
ρ ρ ρ ρ α
ρ ρ ρ ρ
ρ ρ ρ ρ
− − +
⎞− + − − − + + − − − − +⎟
⎠
− + − − − − − + − − − −
− − + − − ( ) ) ( )
( )( ) ( )( )
( ) ( ) ( )( )( )
( ) ( )( ) ( )( ) ( )( )( )
3
3 2
4 32 2 2
1 1 3 2 1 2 1 3 2
22 22 2 2 2 2 2 2 2 2 2
1 2 1 1 2 2 1 3 4 2 1 2 1 4 1 2 4 1 3 2
22 22 2 2 2 2 2
1 4 2 2 1 3 2 2 1 2 2 2 3 4 1 2 4 1
sin
4
4 6 6 2
16 16 0
p
p
r R R
R r x D d r L r R R R r r R R r R
R r R R x D d L r r R r R
ρ ρ α
ρ ρ ρ ρ ρ ρ
ρ ρ ρ ρ
ρ ρ ρ ρ ρ ρ
− +
+ − + − − +
− + + − − + + + − + − +
+ − − + − + + + − − + − =
(20)
7. Acknowledgments
This work has been partially funded by the European projects NEXT, acronyms for “Next Generation of Productions
Systems”, Project no° IP 011815. The authors would like to thank the Fatronik society, which permitted us to use the
CAD drawing of the Machine VERNE what allowed us to present well the machine. The authors would also like to
thank Professor Wisama KHALIL for his useful remarks that helped us accomplishing this work.
8. References
[1]J.-P Merlet, Parallel Robots. Springer-Verlag, New York, 2005.
[2] J. Tlusty, J.C. Ziegert and S. Ridgeway, Fundamental comparison of the use of serial and parallel kinematics for
machine tools, Annals of the CIRP, 48 (1) 351–356, 1999.
[3] Ph. Wenger, C. Gosselin and B. Maille, A comparative study of serial and parallel mechanism topologies for
machine tools. In Proceedings of PKM’99, pages 23–32, Milan, Italy, 1999.
[4] M. Weck, and M. Staimer, Parallel Kinematic Machine Tools – Current State and Future Potentials. Annals of the
CIRP, 51(2) 671-683, 2002.
[5] D. Chablat and Ph. Wenger, Architecture Optimization of a 3-DOF Parallel Mechanism for Machining Applications,
the Orthoglide. IEEE Transactions on Robotics and Automation, volume. 19/3, pages 403-410, June, 2003.
[6]A. Pashkevich, Ph. Wenger and D. Chablat, Design Strategies for the Geometric Synthesis of Orthoglide-type
Mechanisms, Journal of Mechanism and Machine Theory, Vol. 40, Issue 8, pages 907-930, August 2005.
[7] J. M. Hervé and F. Sparacino, Structural synthesis of parallel robots generating spatial translation. In Proc. 5th Int.
Conf. Advanced Robotics, volume. 1, pages 808–813, 1991.
[8] X. Kong and C. M. Gosselin, Type synthesis of linear translational parallel manipulators. In Advances in Robot
Kinematic, J. Lenarcic and F. Thomas, Eds. Norwell, MA: Kluwer, pages 453–462, 2002.
[9] K. E. Neumann, Robot. U. S. Patent 4 732 525, Mars 22, 1988.
16
[10] T. Toyama et al., Machine tool having parallel structure. U. S. Patent 5 715 729, February. 10, 1998.
[11] R. Clavel, DELTA, a fast robot with parallel geometry. In Proc. 18th Int. Symp. Robotic Manipulators, pages 91–
100, 1988.
[12] O. Company, F. Pierrot, F. Launay and C. Fioroni, Modeling and preliminary design issues of a 3-axis parallel
machine tool. In Proc. Int. Conf. PKM 2000, Ann Arbor, MI, pages 14–23, 2000.
[13] H. S. Kim, L-W. Tsai, Kinematic Synthesis of a Spatial 3-RPS Parallel Manipulator. In Journal of mechanical
design, volume 125, pages. 92-97, March 2003.
[14] O. Ibrahim and W. Khalil, Kinematic and dynamic modelling of the 3-RPS parallel manipulator. In 12 IFToMM
World Congress, Besancon, June 2007.
[15] D. Kanaan, Ph. Wenger and D. Chablat, Workspace Analysis of the Parallel Module of the VERNE Machine.
Problems of Mechanics, № 4(25), pages 26-42, Tbilisi, 2006.
[16] X.J. Liu, J.S. Wang, F. Gao and L.P. Wang, On the analysis of a new spatial three-degree-of freedom parallel
manipulator. IEEE Trans. Robotics Automation 17 (6) 959–968, December 2001.
[17] Nair R. and Maddocks J.H. On the forward kinematics of parallel manipulators. Int. J. Robotics Res. 13 (2) 171–
188, 1994.
[18] Y. S. Martin, M. Giménez, M. Rauch, J.-Y. Hascoët, A new 5-axes hybrid architecture machining center. In 5th
Chemnitzer Parallel kinematic Seminar, pages 657-676, Chemnitz, 25-26 April 2006.
[19] M. Terrier, M. Giménez and J.-Y. Hascoёt, VERNE – A five axis Parallel Kinematics Milling Machine. In Proc. of
the Institution of Mechanical Engineers, Part B, Journal of Engineering Manufacture, volume 219, Number 3, pages.
327-336, March, 2005.
[20] D. Kanaan, Ph. Wenger and D. Chablat, Kinematic analysis of the VERNE machine. IRCCyN technical report,
September 2006. Available online at http://www.irccyn.ec-nantes.fr/~chablat/Verne.html.
| 0non-cybersec
| arXiv |
[Spoiler S4E10] "A small man can cast a large shadow." Latest 'Beautiful Death' from HBO.. | 0non-cybersec
| Reddit |
sql query that groups different items into buckets. <p>I am trying to write a query that returns the count of items whose price falls into certrain buckets:</p>
<p>For example if my table is:</p>
<pre><code>item_name | price
i1 | 2
i2 | 12
i3 | 4
i4 | 16
i5 | 6
</code></pre>
<p>output:</p>
<pre><code>range | number of item
0 - 10 | 3
10 - 20 | 2
</code></pre>
<p>The way I am doing it so far is </p>
<pre><code>SELECT count(*)
FROM my_table
Where price >=0
and price <10
</code></pre>
<p>then </p>
<pre><code>SELECT count(*)
FROM my_table
Where price >=10
and price <20
</code></pre>
<p>and then copy pasting my results each time into excel.</p>
<p>Is there an automatic way to do this in an sql query?</p>
| 0non-cybersec
| Stackexchange |
Replace sqlite3.3.6-5 for sqlite3.7.0-1 on centos5. <p>I want to update my sqlite3 version. I'm using centos5 (VPS requeriment), I have a new version downloaded (.rpm) and a previous installed (with the os) I have this error.</p>
<p><img src="https://i.stack.imgur.com/WZc13.png" alt="image of my problem"></p>
<p>Well, I have noob on centos distributions, and dont know well the yum, rpm yet, but I cant found a solution for this.. Any idea? Sorry my bad english.</p>
<p>Is a test environment, I will havent problem with install the two versions on same time if these are posible. Thanks</p>
| 0non-cybersec
| Stackexchange |
What file types might be vulnerable to SQL injection?. <p>I am learning about SQL injection and Google dorks. I have seen that there are three file types that can be vulnerable to SQL injection, <code>.php</code>, <code>.aspx</code> and one more.</p>
<p>I can't find the third one... The first two are related to the server side, so the third one should be that too. At the start I thought <code>.html</code> might be good, but then I understood that I need something related to server side.</p>
| 1cybersec
| Stackexchange |
How do projects manage security with so many dependencies in open source projects?. <p>Some node.js libraries (just as an example) can pull in literally hundreds of dependencies. Some of these dependencies are small packages that only have one contributor. Often times the contributor doesn't even have any personal information listed other than their username.</p>
<p>How is it possible to trust that nobody in those hundreds of libraries will never act maliciously, get their account hacked, have a change of heart, purposefully introduce a vulnerability, etc?</p>
<p>It seems that all it would take is one point in the chain to get compromised, or have never had good intentions from the beginning, and that could lead to huge security problems or data breaches. A compromised plugin in a build system could steal source code.</p>
<p>It just seems like the wild west and a disaster waiting to happen. Do companies really review the source code of every single package they use, and the changes on every single update? That just sounds unmaintainable.</p>
<p>I could understand trusting a paid library published by a business, but I don't understand projects using these deeply nested dependencies published by internet strangers.</p>
<p>I guess what my question is that I am having trust issues and don't know how to properly include a library without worrying that I could accidentally compromise a customer's business.</p>
| 1cybersec
| Stackexchange |
PsBattle: Dog soaring for a ball. | 0non-cybersec
| Reddit |
How to install MySQL 5.6 in Ubuntu 14.04 Desktop?. <p>Which are the steps to install MySQL in Ubuntu 14.04 (Trusty Tahr)?</p>
| 0non-cybersec
| Stackexchange |
How to use spot instance with amazon elastic beanstalk?. <p>I have one infra that use amazon elastic beanstalk to deploy my application.
I need to scale my app adding some spot instances that EB do not support.</p>
<p>So I create a second autoscaling from a launch configuration with spot instances.
The autoscaling use the same load balancer created by beanstalk.</p>
<p>To up instances with the last version of my app, I copy the user data from the original launch configuration (created with beanstalk) to the launch configuration with spot instances (created by me).</p>
<p>This work fine, but:</p>
<ol>
<li><p>how to update spot instances that have come up from the second autoscaling when the beanstalk update instances managed by him with a new version of the app?</p>
</li>
<li><p>is there another way so easy as, and elegant, to use spot instances and enjoy the benefits of beanstalk?</p>
</li>
</ol>
<p><strong>UPDATE</strong></p>
<p>Elastic Beanstalk add support to spot instance since 2019... see:
<a href="https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html</a></p>
| 0non-cybersec
| Stackexchange |
why can alliance attack me while not beeing in warmode ?. im farming my route and im getting killed everytime im not in warmode but they can attack me and i dont know why did i miss something ?
| 0non-cybersec
| Reddit |
Open Letter to Ellen Degeneres: Don't Promote Theresa Caputo, the "Long .... | 0non-cybersec
| Reddit |
Optimization based on partial derivative. <p>I want to maximize $f(a,b,c)$ over the variables $a,b,c$,
such that </p>
<p>1) $0\leq a\leq K$, </p>
<p>2) $0\leq b\leq K$, </p>
<p>3) $0\leq c \leq K$</p>
<p>where $K$ is a constant.</p>
<p>The $f(a,b,c)$ is some rational function (2nd order polynomial divided by 1st order polynomial in $a,b,c$). </p>
<p>The observation is that $\frac{\partial f(a,b,c)}{\partial a} > 0$, and that $\frac{\partial f(a,b,c)}{\partial b} > 0$, for the domain. Both of these derivatives are continuous, smooth, and well-behavior on that domain.</p>
<p><em>I am wondering to solve this maximization problem, am I safe to simply put $a=K, b=K$, and simplify it to</em>:</p>
<p>$Maixmize$ $f(a=K, b=K, c)$ such that $0\leq c \leq K$</p>
<p>Is this correct??
In this case, this would be a single variable optimization problem. </p>
| 0non-cybersec
| Stackexchange |
How does Tor protect against fake entry nodes / total redirection?. <p>There is much material on how to protect yourself from malicious exit nodes, especially by using SSL and minimizing the leakage of identifying information (user-agent, screen size, etc.).</p>
<p>However, I was wondering why an attacker could not just setup a bunch of fake Tor <em>entry</em> nodes, and redirect your outgoing connections to them (assuming you must route all data through their network). They could even virtualize or fake the whole Tor network with ease.</p>
<p>What measures does Tor have against such attacks, and what can a user do against it?</p>
<p>Are there e.g. a list of hardcoded entry servers with known public keys? If so, how do I know that those priviliged servers are not operated by the NSA or the Chinese or whoever? They could be a) compromized from day one, or b) someone could have manipulated <code>torproject.org</code> when I downloaded the software, and replaced the server list and checksums.</p>
<hr>
<p>(I hope this doesn't sound too paranoid. I got this idea when I was working a large (US-)government-run facility, and noticed how pervasive their computer security measures were (probably with good reason). If I were a dissident or had something to hide, they could have easily 'rabbit-holed' my entire network. I guess this is a much more pressing problem in other countries.)</p>
| 0non-cybersec
| Stackexchange |
When a pistachio is cracked awkwardly,. | 0non-cybersec
| Reddit |
The Man with the Shears. UPDATE: I've made an audio video of this story on my new Youtube channel. Here's the link if you're interested in listening while you read:
https://www.youtube.com/watch?v=YKDpQzLwF3I
My dreams had always been vivid and intense, for better or for worse. Some people have told me they “never dream” or “they have dreams, but never remember what they are about.” Me? My dreams were like movies, complete with complex characters and dynamic plots. I created entire worlds with my dreams. I lived entire lives. Sometimes it’s a lot of fun. When I was about six, I had a dream that I was the sixth member of the Power Rangers, and with the help of Wolverine we were able to defeat the evil King Bowser and his robotic Foot Soldiers.
On the other hand, there were times that I had such petrifying nightmares that I thought I would never feel safe in my own room again. I recall waking up to find that my mother’s head had transformed into that of an alligator, and she chased me around the house until she cornered me in my room, screaming that she wanted to eat my insides. It sounds puerile now, but I remember waking up in a cold sweat, and it was a week before I would let my mother hug me again.
Most of the time, though, I loved dreaming. I’m a writer, so I loved to draw upon my dreams as inspiration. I felt like my imagination was unleashed while I was asleep. My subconscious could take my imagination to destinations that were otherwise unreachable. My waking imagination was a horse-drawn carriage, and my dreaming imagination was a starship. I used to wish I could live my life in that half-awake state between consciousness and reality.
That was before.
When it all began, my father had died a year earlier in a car accident. I was there when it happened. I was riding in the passenger seat of a car with him, and we were listening to Aerosmith and talking and laughing like we did a thousand times. There was the road ahead, and then there was a semi-truck, and then we were upside down.
I spent one night in the hospital. So did my father. I woke up the next morning. My father didn’t.
Suffice to say, it was tough, but a year later, I felt more or less okay. There were good days and bad days, but I really surprised myself at how well I handled the loss. All throughout my formative years, losing a close family member was one of my worst fears. I went in to see my doctor for a routine checkup, and he offered to refer me to a mental health professional if I ever felt like I needed to talk anything out. I appreciated the offer, and I intimated the possibility, but I really felt like I’d been doing okay. I’m not one of those nonverbal males who push down all of their emotional baggage until they die of a bleeding ulcer. I have some close friends and family with whom I’m comfortable enough to share whenever I’m feeling down.
The truth is, other than my father’s passing, that year went extraordinarily well for me. I got a promotion at my job that came with a decent raise. I wrote a short story that got published in a local literary magazine and I was awarded five hundred dollars. Best of all, I got a girlfriend named Brooke who I could only describe as a “perfect ten.” Seriously. Brooke was like, model hot, and I’m far from it. She knew it too. She frequently liked to tease me that she was way hotter than I was, which sounds mean, but she knew how to give just the right amount of teasing and could take it just as well as she could dish it out. I never thought I’d snag a girl like her. I was fine, except for the dreams.
You see, I dreamt pretty frequently of my father. Probably that’s normal…the loss was never far from my mind, and being the vivid dreamer that I am, it was only natural that he should make an appearance. I wish that these dreams were of happier times, but to be honest the dreams were unsettling.
The problem was, in my dreams I knew my father was dead, and yet I saw him and spoke to him. It’s not like I knew I was dreaming, and I don’t remember thinking he was a ghost either. It’s hard to explain. Every time, I knew my father was dead, and I also knew that he was right there, but in my dreamlike state, the logical part of my brain never penetrated the contradiction. He was both dead and alive, and it never occurred to me that this was impossible. Both were correct. This was profoundly frustrating. I can remember a dream where we were at a family reunion, and my father was just sitting at a table by himself while the rest of my family was sitting together and laughing, and I kept trying to get them to come over and sit with him because he was dead and they needed to spend some time with him before he remembered.
I remember another where he and I were bowling, but he seemed confused and couldn’t quite remember how to properly hold or throw a bowling ball, and I kept trying to comfort and console him and tell him it was okay because dead people don’t tend to go bowling. The last time I dreamt of him, it was frightening.
I can remember him driving a car, with me in the passenger seat. Ominous, I know, but I honestly wasn’t thinking that at the time. My first thought, actually, was, “Dad…you’re dead. I really don’t know if you should be driving.”
I said this to him. He didn’t seem to hear me, so I didn’t say anything for a while because I didn’t want to offend him.
Then, my father turned to me, looking at me with eyes that displayed no emotion or recognition. He looked at me, but didn’t really see me. His face in that moment still haunts me, because when my father was alive, there was always some sort of emotion. Love. Pride. Failing that, there was at least frustration, anger, sadness, or weariness. He showed none of that. He was utterly blank.
His voice, too, sounded unlike him when he spoke. Totally devoid of any emphasis or dynamism, he said, “You shouldn’t be here.”
“What?”
“You shouldn’t be here.”
“I shouldn’t…but dad…” I remember feeling my voice cracking with emotion, even in my dream state. “Dad, you’re the one who shouldn’t…be here.”
“You have to wake up now.”
“What?”
SNIP!
Just like that, I was jolted awake. In the movies, you always see people waking from a nightmare and sitting bolt upright in their beds with their eyes wide and their brows sweating. I’m sure I didn’t do that, exactly, but that’s what I felt like as my bulging eyes frantically scanned my bedroom.
Something had woken me up.
SNIP!
Something or someone had made a noise and woken me. My eyes were adjusted the dark, but I didn’t see anyone else in my room. I live with cats, but I didn’t see them even when I turned on the lights and searched the hallway.
Nothing.
I looked at my clock. 4:30. I had to be awake for work in about two hours. I tried to go back to sleep, but all I got was the aggravation of an insomniac desperate for rest that will not come. I could not drift off again, and my alarm screamed at me two hours later.
What kept me awake? It wasn’t the dream of my father. It wasn’t the pressure of getting needed rest before a busy day at the office. It was that sound.
SNIP!
I’d distinctly heard it. It was the sound a pair of shears makes, but twenty times louder. I figured it must have been in my dream…but no. No, I was certain that it had happened in my bedroom. The sound had been right next to my ear.
****
The next day at work I doubled my usual intake of coffee, and I still kept nodding off at my desk. My bloodshot eyes made me look like I was hungover, but my co-workers were kind enough not to say anything. Even a year after my father’s passing, they still forgave me for being a little disheveled from time to time. Even my boss said nothing when he stopped by my office, though he did give me a once-over that made me feel self-conscious. I hadn’t bothered to shower or press my shirt as I usually did each morning.
That evening, my roommate John and I were sitting around having a few beers and playing Super Smash Brothers. I’m usually able to hold my own in that game, but I was getting my ass handed to me match after match. His bedroom is right next to mine, so I asked if he’d anything peculiar the night before.
He said, “I dunno, dude. Like, what do you think I might have heard?”
“It was, like, a snip.”
“A ‘snip?’”
“Yeah.”
I wanted him to tell me that I was crazy, or that I must have been dreaming, but instead he said the worst possible thing. “Yeah, I heard something that woke me up too.”
“What?” I paused the game.
“Yeah. When do you think that would have happened?”
“At like, 4:30.”
He nodded. “Yeah. Yeah, I definitely heard something around then. I couldn’t quite place what it was. I figured it was a cat or one of you guys.”
“Did it sound like a snipping noise?”
“I couldn’t really tell,” he replied, “but it sounded like it came from your room.”
I felt pins and needles begin in my chest and prick their way down my arms and legs. I swallowed hard, trying not to betray any sort of emotion in my face. Suddenly, John broke into a goofy grin and relief washed over me.
I punched him in the arm. “You fucker.”
“Ow, dude!” he said, laughing. “Sorry! You just make it too easy.”
“Right…”
“Bro, noises happen at night. It was probably the goddamn cats.”
“Yeah,” I replied. I un-paused the game, and instantly John’s Pikachu body slammed my Kirby, causing him to fly offscreen to his death.
****
That night I dreamt again, but not of my father. God, I wish I had dreamt of anything else.
I recognized the setting: it was clearly my house at night. The strange thing was I didn’t have the sense that I was myself, but rather that I was observing from somewhere far away. Was I having an out of body experience?
A brief word about the layout of my home: I live on the second floor of a triplex building. You can enter my house through the back by way of a set of stairs leading up to a deck. The back door opens into my kitchen. You can then move through the kitchen into the living room, and on the far wall there is a set of stairs leading to the second floor where there are three bedrooms for my roommates and myself.
My view was from the middle of the living room looking through the door into the kitchen. For several long moments there was no sound but the ticking of a clock and the gentle wrrr of the central air. I tried to move, but couldn’t so much as look around. I tried to speak, but couldn’t even move my lips. Again, even though I could see clearly, I had the sense that I wasn’t really myself, but a silent observer. This gave me a despairing sense of helplessness. I was Alex from A Clockwork Orange, my eyes pried open to a something I didn’t want to see.
Then I heard a metallic jostling noise. Someone was jiggling the knob of our back door. They were trying to turn it, but they couldn’t quite get the door to open. Was it locked? No, if that were the case, they wouldn’t be able to turn the knob at all. So why the struggle? I was incapable of blinking, but even if could, I’m sure my eyes would have been locked on the scene.
The knob turned. The door opened just a crack. Then, it swung open in full.
What I saw is etched in my mind forever. To be honest, I’m struggling to type with trembling fingers as I recall the numb sense of horror I felt as I beheld the thing for the first time.
The creature might almost have been human. It had two arms, two legs, and it stood at about my height, but I cannot conceive that any human could endure the anguish of this thing’s existence. It was naked, and its skin was very pale and covered in cuts of varying length and depth. Some looked like years-old scars, and some of the wounds were one day fresh. The thing’s age was impossible to know; it might have been thirty years old or ninety. Its physique made it seem male, but it had no genitals. It also was lacking nipples, a belly button, or any visible hair.
Its feet, devoid of toes, looked like a pair of milky-white potatoes, and the thing seemed to struggle to remain upright as it walked. Three fingers had been removed from each of its hands, leaving only the index and thumb of each. These held two pairs of shears which were jagged, rusty, and nearly two feet long. Every so often one of its hands would twitch, and it would SNIP! the air with a sound that seemed to deafen me even though it came from such a small thing. As terrifying as those weapons were to behold, it was nothing compared to the face. Its ears, nose, and eyelids had been cut off leaving gaping holes in their stead. Its eyes were bloodshot and dry as a result. Worst of all, its mouth had been snipped at the corners, giving an unnatural, unending grin.
The thing made no noise as it stalked through the kitchen, snipping the air and shuffling along on its mutilated feet. I could do nothing but stare, taking in every inch of the thing’s lean, grotesque body. Suddenly, my perspective changed like the feed from a security camera system. I was following the creature as it stalked through my home. It walked uncertainly like a toddler or a drunk, and seemed to almost fall once or twice, but it never lost its footing as it maneuvered around the living room furniture.
At the bottom of the stairs it seemed to linger for a fraction of a moment, but then it took its first step up, and then its next. I watched from just behind the thing as it ascended, and on each step it would SNIP! one of its too-long shears. Oddly, the steps never creaked, even as it stopped and stumbled. The only sound was the irregular SNIP! SNIP-SNIP!
My next perspective was of the top floor of my house, but it seemed like the roof had been removed. I could see both the upstairs hallway, and inside of my bedroom. I even saw myself, sleeping soundly in my own bed. Slowly the creature came into view as it reached the top of the steps. At this point, even in my disembodied state, panic set in, because I knew I was the creature’s target. The shears hungered for blood, and I was to be their sustenance. I willed myself, pleaded with myself to wake up and see the danger, or for my silent spirit to repossess my body so I could flee.
The thing stopped just outside of my bedroom. I was screaming in my mind to WAKE UP! To RUN AWAY! Perhaps I heard my pleas, because my body grunted softly and rolled to the side.
The thing was right by my door now. Slowly, its right arm came up, raising its shears to its face. An impossibly red tongue slithered out of its too-wide mouth, licking the blade of the shears before taking them between its teeth. Its hand freed of this burden, it wrapped its thumb and forefinger around the knob of my door. It seemed to shudder with excitement, and its left hand twitched.
SNIP!
Abruptly, I was in my bed again. I was drenched in sweat, yet I pulled the covers all the way up to my chin and slammed my back against the wall, cowering. My eyes were locked on the doorknob. I couldn’t be certain, but in the dark I thought I could see it moving ever so slightly. I strained my ears for a sound that would confirm my fears, for the jostling of my doorknob, or worse: the thirsty SNIP! SNIP! of those ruthless shears.
I stared at the door unblinkingly for an hour, and sleep was the farthest thing from my mind. After that, I chanced moving enough to turn on my bedside lamp. I finally thought to pick up my cell phone and call John, who was sleeping next door. He sounded annoyed until I told him there was someone in the house.
Even though I protested, he got up out of bed and looked around for me.
As you’ve probably guessed, there was no sign that anyone had been there.
Just another one of my hauntingly vivid dreams, I thought. I was embarrassed that I’d dragged poor John out of bed over it. I felt stupid, rather than scared. But I still didn’t sleep.
****
The next day I was almost too tired to even go over to Brooke’s house, but when she sent me a text saying “I’ll make it worth your while ;-)” I was convinced. The evening we relaxed on her couch, cuddling and watching a dumb movie that we didn’t want to pay much attention to. Brooke was always easy to talk to, so I described my dream to her.
“Ew,” she said when I had finished, and that made me laugh.
“Man, that was a bad one,” I said. “I mean, nightmares always just sound dumb in the retelling, but this one really got to me.”
“No, I believe you. That sounds awful.”
I shook my head. “I thought I was done with all that. I haven’t had a bad one like that since I was a kid.”
For a moment, she didn’t say anything. I thought that meant the conversation was over, but then she asked, “Did I ever tell you I used to have night terrors?”
I was surprised. “No.”
“It’s a bit different from having a nightmare. Doctors always told me it was more of a reaction of fear when you transition from one stage of sleep to another, but that was never good enough for me. They didn’t understand.” She shuffled slightly. “I remember feeling, not that I had imagined something awful, but that something was coming for me. I remember thinking I was going to die…even if I couldn’t point to how.” She looked into my eyes. “Are you still dreaming about your dad?”
I blinked twice and nodded. “Sometimes.”
“We all have our demons. I think, in dreams, they show themselves in the worst ways.”
With a lump in my throat, all I could say was, “Yeah.” Instead of saying anything more, I pulled her into my arms. I whispered in her ear, “I’m so lucky I have you. You make everything better.”
“You do too.” We broke from the hug. Then she placed a hand on my knee, which started to travel north up my thigh. “I know something else that could make you feel better…”
You can imagine what happened next.
But we both had an early morning at work, so I didn’t spend the night. I went home. I went to sleep.
****
Musk. That’s what wakes me. My eyes are heavy from two sleep-deprived nights, and I almost drift off again.
But I don’t.
Something is wrong. It’s not a sound this time. No. It’s musk. It’s the smell of an un-bathed dog, and it’s filling the whole room. It’s an itch in my nose that scratches at my consciousness until I open my eyes.
And I scream.
The monster is right there. It’s RIGHT THERE. It is standing over me, smiling its slit-mouthed smile, it’s lidless, bloodshot eyes boring straight into mine. The thing is in my room, and it’s here to kill me. It’s right there.
I scream and cry, louder than I ever have before, and I feel my throat going hoarse. I pray that my roommates or my neighbors or my mommy will hear me and come and rescue me.
Somehow I know that I will not be heard. I start scrambling to get up, but when I try to move a searing, stabbing pain starts and my wrists and shoots up my arms to my chest and to my brain so that I squeal and my vision blurs. My eyes snap to my wrists, and the sight brings bile bubbling to the back of my throat. My arms are stretched out to my sides, and each of my wrists is pinned to the headboard with a pair of those long, rusty shears. Blood flows from the wounds, running down my arm in rivulets and soaking my mattress. My first instinct is to try and pull free, but even the slightest twitch of my arms causes a jolt pain that attacks my entire nervous system. It’s like being stabbed all over my body. I scream, and it’s all I can do not to vomit on my chest.
This has to be a dream! This has to be a dream! I tell myself. It must be, because this creature could not exist. It must not exist. If horror like this exists in the world, then I’ve been a fool for ever feeling happy and safe. If this is how I was always meant to die, then what was the point of living?
Though the monster’s shears have been employed to drain my lifeblood from my wrists, it somehow has materialized two more, and the monster eyes me up and down, twitching and snipping hungrily. It’s eyes linger on my bloodied arms, and the sight of the carnage seems to arouse it. Its lips peel back to reveal yellowed teeth and a blood-red tongue.
SNIP! SNIP!
It seems to be considering what next to do with me. I’m pleading unintelligibly, begging it to let me go or for this nightmare to end, but to no avail. The thing cannot, or more likely, will not hear me. If anything, my screams seem to entice it further, its lips pulled back and it’s jaw hanging loose in a silent cackle.
It leans in as though to get a closer look at my tear-streaked face. The wet-dog smell pervades my senses. I gag, and the thing leans in closer and closer. With both of its toeless feet still firmly planted on the ground, it seems impossible that the thing should be able to lean so far toward me without tumbling down on top of me. Still, it does, and it inhales my scent through the slits that used to be its nose. The thing reverts to its upright position. As the creature steps away from me I dare to feel an iota of relief, but it flutters away as the creature slowly falls to its knees at the foot of my bed.
SNIP! SNIP!
The creature slowly raises the shears in its left hand up to its face. It’s red, red tongue snakes out from between its lips and licks the blades tantalizingly. It then takes the shears between its teeth, and with its freed hand it snatches my right ankle up with its thumb and forefinger. The icy-cold grip of its spindly fingers is impossibly strong. I kick and kick, but the creature is utterly unphased. I use my other foot to kick at the monster’s forearm. This causes pain to shoot up from my wrists as my body gets jostled about, but the monster only grins wider. It’s grip tightens, nearly crushing my ankle. I can only whimper pitifully.
It raises its right-hand shears up, and I know what its target must be.
“No…please…” I manage only those two words.
But when the cutting begins I howl unintelligibly into the darkness as the thing snips into the flesh of my ankle, spewing blood and crunching through flesh, muscles, bone, and sinew.
SNIP!
I cry.
SNIP!
I howl.
It seems impossible that even a creature such as this should be able to cut through a human leg with just a pair of shears, but my flesh gives way like soft cheese, and each SNIP! takes me closer to insanity.
It takes about a dozen good cuts, and then my foot rips free. I scream and scream as I watch the thing raise my blood-slicked appendage into the air like a trophy. My stomach finally gives, and my vision clouds from the pain and blood loss. I can feel myself growing cold, and but even now the thought of death is secondary to the horror of the creature.
The monster’s jaw drops open, allowing its other pair of shears to clatter to the floor. It opens its cut mouth impossibly wide, revealing all of its teeth and that gory tongue. It manages to jam my entire foot into its mouth and it begins to chew. CRUNCH! CRUNCH! Its yellowed teeth make quick work of it, bones and all.
As unconsciousness takes me, all I hear is CRUNCH! CRUNCH!
SNIP!
****
I woke up screaming and thrashing around, and two nurses had to come in and restrain me so that I didn’t tear out my IV. It took a good five minutes for me to understand that I was in the hospital. It was another ten before my breathing slowed.
My heart was still palpitating when the doctor came in to see me. After a brief exchange of pleasantries, she asked me, “Do you remember what happened?”
I told her.
“Uh huh,” was all she said. I was both impressed and annoyed that her face did not betray her thoughts.
“How did I get here?” I demanded. “Who…found me? Is that thing still in the house?”
The doctor grabbed my arm to check my IV and the bandages on my wrists. “I’m afraid you’re a bit delusional. That’s nothing to be alarmed about. You’re probably dehydrated, and we have you on pain medication, so this is pretty normal. Are you sure you don’t remember what happened?”
“Yeah!” I exclaimed, though my “exclamation” was little more than a whisper. “I told you. A monster…”
“There was no monster, hon. You don’t remember the accident?” the doctor asked.
“Accident?”
She sighed. “You were in a car accident. It was bad. A collision with a semi-truck knocked you off of the road, and they say you rolled half a dozen times. You were badly hurt. You’ve been out for three days.”
“No, I…” and I stopped. I stopped because what she said made more sense. Of course. An accident. I didn’t remember driving, but I must have been. Of course it made more sense than a monster with scissors devouring my foot.
The doctor said, “Listen…over the past couple of days we’ve had to go through several procedures. This is going to come as a shock to you, but…I’m afraid we had to amputate your right foot.”
“You…you…” I pulled the sheet up slightly, and I felt the blood drain from my face. That much was true. My bare left foot was exposed, and then the white bandages covering the stump-end of my right leg.
“I’m very sorry,” the doctor said. “Um…listen. Your mother and sister are here. I realize you’ve just endured a shock, but are you ready to see them?”
“I…yeah. I think so.”
They came rushing in, and there were several minutes of tears, sobbing, and unending hugs. For minutes we just sat there and embraced as we had far too many times that year.
“Thank God you’re okay,” my mom said between wracking sobs. “I didn’t think you were ever going to wake up. I didn’t think…”
“I’m okay,” I assured her. Even then, I had to be the strong one. “This…this sucks. But I’ll get through this. We’ll get through this.” There was more crying and hugs. My sister was tearful, but otherwise strangely quiet. I understood. I could only imagine what she and my mother had been going through the past three days. We lost my father to a car accident just a year ago, and now they’d faced the very real possibility of losing me the same way. I was the one who broke the silence by saying, “The thing is…the thing is, I don’t even remember driving.”
My mom started wailing, suddenly inconsolable. Strange, I thought. Why did that of all things set her off? She collapsed into my sister’s chest. My sister, eyes red and wet, took her hand in mine.
She said, “You weren’t driving.”
I blinked a few times. “Then who was?”
My sister couldn’t bear to look at me. In a choked voice, she said, “Daddy’s dead…”
“I…I know,” I replied.
This set my mother going even worse. She was shaking, and so was my sister.
She said, “What do you mean, you know?”
“I know. I’m not delirious, whatever these doctors say. I know dad died last year.”
My sister shook her head. “No…God, no. No. You couldn’t know. Dad didn’t die last year. He died while you were still sleeping. He died last night.”
****
I’m sorry if this is disappointing. This story ends with the old “it was all a dream” cliché. I’m sorry if that’s a letdown compared to pale monsters and pedal mutilation, but think about what that meant for me. It was all a dream. All of it. A year of my life was gone.
I’ve had to go through the entire grieving process anew, and had to relive all the tears and all the well-wishers. This time it’s been worse, though, because I am different than I was, and nobody can understand why. Regardless of what people told me, I felt that he’d been gone a year. I tried to explain this to my sister, and she accused me of being callous. I’m sure my mother felt that way too, though she’d never say it.
Since the accident I’ve drifted through a perpetual fog of confusion. It seems like every other day or so I learn that something I took for granted was a lie, and each time it’s like waking up from another dream. I never got that promotion. I never published that story. Worse, Brooke never even existed. That was really the worst thing, even worse than losing my foot. I actually still miss her. My memories of her are still so clear and exquisite, though just like all dreams, they are fading with each passing day.
Those memories are fading. What doesn’t fade, what never fades, is the too-wide smile of the scissor creature as my foot disappeared down its bloody throat.
I don’t think I’ll ever understand exactly what happened to me, though I think about it every day. The way I see it, there are three possibilities.
One: it really was all a dream, and predicting my father’s death was just some tragic coincidence. Personally, I have trouble accepting that.
Two: I had some sort of dreaming premonition. Maybe I have the gift of foresight, although if that’s the case I have never experienced it before or since. I have trouble accepting that too.
Three: the creature really did this to me. All of it. It manufactured that year of my life, prolonging my grief and my pain, and in the end, devouring a part of me. Maybe each scar that it carried on its marred body had a story. I’ve often wondered, did it mark itself this way, to remember its victims? Maybe it has been doing this to people forever.
In a way, it’s never truly gone, especially when I lay down to sleep at night. I’ve never exactly dreamt of the creature again, but the image of it is burned into my mind’s eye and becomes visible whenever night falls. I take sleeping pills, and often drink excessively. Even that doesn’t help much.
That’s why I had to write it all out. Maybe I’m posting this as a cry for help. Maybe I’m hoping someone out there has had a similar experience and could help me sort thing out. Maybe the very act of writing is my way of sorting it out. I hope when I put it in perspective I can finally laugh about it. Nightmares seem so silly in the retelling.
But last night…
Last night I dreamt of my father.
It was he and I, driving in the car on a sunny country road, and he looked at me with the eyes and soul of the dead.
He told me that I have to wake up.
UPDATE: I thought this story was over, but a few night ago I received a private message from a woman who had a similar experience. You can find it here: https://www.reddit.com/r/nosleep/comments/4qtlwi/the_man_with_the_shears_part_2/
| 0non-cybersec
| Reddit |
Sendmail says it has sent, but doesn't actually send. <p>I installed sendmail using this tutorial:</p>
<p><a href="http://pc-freak.net/blog/install-sendmail-debian-gnu-linux/" rel="nofollow">Install sendmail debian gnu linux</a></p>
<p>I am using this command to send my test email:</p>
<pre><code>mail -s "Subject" "[email protected]" <<< "This is the body"
</code></pre>
<p><code>mail.log</code> in <code>/var/log</code> says:</p>
<pre><code>Dec 29 18:15:28 raspberrypi sendmail[14546]: tBU2FSim014546: from=root, size=232, class=0, nrcpts=1, msgid=<[email protected]>, relay=root@localhost
Dec 29 18:15:28 raspberrypi sm-mta[14547]: tBU2FS3h014547: from=<[email protected]>, size=480, class=0, nrcpts=1, msgid=<[email protected]>, proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Dec 29 18:15:28 raspberrypi sendmail[14546]: tBU2FSim014546: [email protected], ctladdr=root (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30232, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (tBU2FS3h014547 Message accepted for delivery)
</code></pre>
<p>Despite what the log says about the message being accepted, I never get the message. Does anyone know what is going on? I didn't know what to include in my question, so if you need more info, just ask. Thank you!</p>
<p>I am using Debian Jessie.</p>
| 0non-cybersec
| Stackexchange |
If a ring $R$ with $1$ has characteristic $0$, then it has a subring isomorphic to the integers.. <blockquote>
<p>If a ring $R$ with $1$ has characteristic $0$, show that $R$ contains a subring that is in 1-1 correspondence with $\mathbb{Z}$ (this subring is called the prime subring of $R$).</p>
</blockquote>
<p>Let $f: R\rightarrow\mathbb{Z}$, if $x \in R$ then $x\mapsto ?$.
As I define $f$ so that it is a 1-1 correspondence? Which subring should consider?</p>
| 0non-cybersec
| Stackexchange |
Hey Jerry, I'm Jerry.... | 0non-cybersec
| Reddit |
How to use spot instance with amazon elastic beanstalk?. <p>I have one infra that use amazon elastic beanstalk to deploy my application.
I need to scale my app adding some spot instances that EB do not support.</p>
<p>So I create a second autoscaling from a launch configuration with spot instances.
The autoscaling use the same load balancer created by beanstalk.</p>
<p>To up instances with the last version of my app, I copy the user data from the original launch configuration (created with beanstalk) to the launch configuration with spot instances (created by me).</p>
<p>This work fine, but:</p>
<ol>
<li><p>how to update spot instances that have come up from the second autoscaling when the beanstalk update instances managed by him with a new version of the app?</p>
</li>
<li><p>is there another way so easy as, and elegant, to use spot instances and enjoy the benefits of beanstalk?</p>
</li>
</ol>
<p><strong>UPDATE</strong></p>
<p>Elastic Beanstalk add support to spot instance since 2019... see:
<a href="https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html</a></p>
| 0non-cybersec
| Stackexchange |
Is it a good practice to set an object to null after processing?. <p>I have scenario like this:</p>
<pre><code>public void processData(String name,String value) {
/* line 1 */ MyDTO dto = new MyDTO();
/* line 2 */ dto.setName(name);
/* line 3 */ dto.setValue(value);
/* line 4 */ sendThroughJMSChannel(dto);
/* line 5 */ dto = null; //As a best practice, should I do this ?
}
</code></pre>
<p>In my program after <em>line 4</em> I don't require <code>dto</code> for further processing. As a best practice, should I set <code>dto</code> to <code>null</code> as in <em>line 5</em> or ignore it?</p>
<p>By setting it to <code>null</code>, I'm expecting fast garbage collection. Is it correct?</p>
| 0non-cybersec
| Stackexchange |
What do u rate this drawing out of 1 or 10. | 0non-cybersec
| Reddit |
The Expendables 2 Official Trailer . | 0non-cybersec
| Reddit |
Conceptually simple linear-time suffix tree constructions. <p>In 1973 Weiner gave the first linear-time construction of suffix trees. The algorithm was simplified in 1976 by McCreight, and in 1995 by Ukkonen. Nevertheless, I find Ukkonen's algorithm relatively involved conceptually.</p>
<p>Has there been simplifications to Ukkonen's algorithm since 1995?</p>
| 0non-cybersec
| Stackexchange |
Hello yello. | 0non-cybersec
| Reddit |
how to detect a file over internet using ping or similar command?. <p>I have a shell script to download some of my stuff over Internet. How can I know if a file exists over the Internet? Let's say I want to know if <code>http://192.168.1.1/backup/01012011.zip</code> exists or not? I have try using <code>ping</code> command, but it shows error, i guess this because <code>/</code> character.</p>
<p>Can anyone can help me? or is there another way?</p>
| 0non-cybersec
| Stackexchange |
Playing Super Smash Bros.. | 0non-cybersec
| Reddit |
After seeing this posted so many times I finally did it. Absolutely amazing. And kid approved! The one and only chicken tortellini!!. | 0non-cybersec
| Reddit |
What is being done in this Integration by Parts proof of $\int_0^1 x^a(1-x)^b \, dx$?. <p><a href="https://i.stack.imgur.com/3Y0Gd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3Y0Gd.png" alt="enter image description here" /></a></p>
<p>Part a.) I was able to understand that you can use integral properties to flip the limits which would essentially make the u sub an x sub but with reverse a and b</p>
<p>part b.) I get this mostly but wouldn't it be <span class="math-container">$1/1$</span> for <span class="math-container">$I(0,a)$</span> therefore making <span class="math-container">$I(a,0)\ne I(0,a)$</span>?</p>
<p>part c.) I used <span class="math-container">$u=x^a$</span> and got <span class="math-container">$a-1$</span> and <span class="math-container">$b+1$</span> which I understand are pulled from the new integral but why can they be pulled from the new integral and how do they prove that <span class="math-container">$a\ge1$</span> and <span class="math-container">$b\ge0$</span>?</p>
<p>part d.) Just plug in. I get it. Simple.</p>
<p>part e.) On the second line I can't understand fully how <span class="math-container">$a$</span> gets to be 1. I understand that every iteration moves the the numbers further from <span class="math-container">$0$</span> so therefore if we set <span class="math-container">$a-1=0$</span> we can understand that <span class="math-container">$b+a$</span> will always give us the correct iteration regardless but if we do that how does <span class="math-container">$a$</span> not become zero when we plug it back therefore making the numerator <span class="math-container">$-1$</span> not <span class="math-container">$1.$</span> It feels like <span class="math-container">$a$</span> is simultaneously two numbers. My only guess is that we are simply taking <span class="math-container">$a$</span> and making it one because we set the rules to be that <span class="math-container">$a$</span> can be no lower I just don't know how you can explain that mathematically.</p>
<p>This is so over my head.</p>
<p>E: Thank you to the moderator that improved my title.</p>
| 0non-cybersec
| Stackexchange |
Science Doggo Does A Smart 🔬. | 0non-cybersec
| Reddit |
Mathematical Induction question Using $n\ge t\ge 0$. <blockquote>
<ol start="5">
<li>Let $n\geq t\geq 0$. Show that $$\sum_{j=t}^{n}\binom{j}{t}=\binom{n+1}{t+1}$$
I am stuck on this question. The fact thats it is multivariable is confusing me.</li>
</ol>
</blockquote>
| 0non-cybersec
| Stackexchange |
Digimaster 18 – New universal mileage correction tool with best quality
. | 0non-cybersec
| Reddit |
A B-26 bomber which later crashed killing 6, loses an engine after it came under anti-aircraft fire over Toulon, France, 1943 - [2316x3000]. | 0non-cybersec
| Reddit |
Hybrid cryptosystem. <p>I'm using RSA (4096) and AES GCM (256) to exchange messages between A and B. A random key for AES is generated, the plain message is encrypted with AES, and the random AES key is encrypted with Bs public key. The encrypted message and key are sent to person B. Lets assume they use an insecure server, they didnt share a secret offline etc. Is there any way for person B to make sure A sent the message and not a man in the middle?</p>
| 0non-cybersec
| Stackexchange |
BORN on Feb 2? You're a 10 of spades person!. | 0non-cybersec
| Reddit |
conjugate subgroups to a given group. <p>let $G$ be a group. Is it true that the only subgroup of $G$ that is conjugate to $G$
is $G$ itself? if $G$ is finite this is clear as conjugate subgroups have the same order but what about infinite groups?</p>
| 0non-cybersec
| Stackexchange |
Real Analysis Proof on Axiom of Completeness. <p>The Question:
Assume $A$ and $B$ are non-empty, bounded above subset of the $\mathbb{R}$ and that $B \subseteq A$. Show that $\sup(B) \leq \sup(A)$. </p>
<p>My Attempt:
Let $A$ and $B$ be as stated. Then by the Axiom of Completeness, $\sup(A)$, and $\sup(B)$ exists and is a real number. Define $a_0 = \sup(A)$ and $b_0 = \sup(B)$. From Lemma 1.3.7., $a_0= \sup(A)$ if and only if for all $\epsilon > 0$, there exists an $a \in A$, such that $a_0 - \epsilon < a$. Similarly, $b_0 = \sup(B)$ if for all $\epsilon_{0} >0$, there exists an $b \in B$, such that $b_{0} - \epsilon_{0} < b$. </p>
<p>I am trying to manipulate these inequalities in some way to get $a_{0} \leq b_{0}$. So am I even on the right track so far? Can you try to give me some hints instead of working out the problem? I would really appreciate it. Thank you very much!</p>
<p>Textbook: <em>Understanding Analysis</em> by Stephen Abbott : <strong>Exercise 1.3.4.</strong>, page 18.</p>
| 0non-cybersec
| Stackexchange |
A continuous function on $S^1$- unit circle .. <p>$$S^1=\{z\in \mathbb C : |z|=1\}$$ be the unit circle. Then which of the following is <strong>false</strong> $?$</p>
<p>Any <strong>continuous</strong> function from $S^1$ to $\mathbb R$ is</p>
<p>A. bounded</p>
<p>B. uniformly continuous.</p>
<p>C. has image containing a non empty open subset of $\mathbb R.$</p>
<p>D. has a point $z\in S^1$ such that $f(z)=f(-z)$</p>
<p>Since $S^1$ is compact any continuous function would be bounded or uniformly continuous so $A$ and $B$ are correct. </p>
<p>For $C$, the constant function does not have any open interval in its image. Thus, $C$ is <strong>the</strong> <strong>false</strong> statement.</p>
<p>That leaves $D$ to be correct. How can I prove the existence of a point $z$ having properties like said in $D$?</p>
| 0non-cybersec
| Stackexchange |
Install an older iOS beta prerelease. <p>My phone was running iOS 9 beta 3 last night when my last backup happened. Today Apple gave me a new phone but when I got home I realized that my version of iOS is iOS 9 beta 4 and my backup will not restaure... Argh.</p>
<p>How can I get iOS 9 beta 3 on this new phone?</p>
| 0non-cybersec
| Stackexchange |
Ubuntu 18.04 - A script to shut down a PC in an event. <p>With support from here or on other forums, I have managed to launch the nVidia Render Farm Multi GPU for network computing in Octane Render Slave Daemon.</p>
<p>Now I am trying to find a way - standalone script or nested in Conky setting, which will allow to shut down PC at certain event?</p>
<p>I need more precisely:<br>
When monitoring nvidia-settings = GPU Utilization will be less than 10% for eg 300sec, then shut down the computer.</p>
<p>So far I have this script from another user to shut down my PC.
But I need to extend it by another time-out condition to avoid turning off the PC as soon as the value falls below 10%. Since there are some load variations in the calculation (for example, from one frame of the animation to the next).</p>
<pre class="lang-bsh prettyprint-override"><code>#!/bin/bash
GPU=$(execi 60 nvidia-settings -query [gpu:0]/GPUCoreTemp -t)
if [[ ${GPU} -le 10 ]]; then
dbus-send --system --print-reply --dest=org.freedesktop.login1 /org/freedesktop/login1 org.freedesktop.login1.Manager.PowerOff boolean:false
fi
</code></pre>
| 0non-cybersec
| Stackexchange |
R/Conspiracy is convinced this is some evil death ray, but really..what IS this thing?. | 0non-cybersec
| Reddit |
Seaman and policeman save a seal's cub, very touching story. | 0non-cybersec
| Reddit |
Oooof. | 0non-cybersec
| Reddit |
Why Reddit was down on Aug 11. | 0non-cybersec
| Reddit |
Why is "hibernate.connection.autocommit = true" not recommended in Hibernate?. <p>In Hibernate API, there is a property <a href="https://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch03.html#configuration-jdbc-properties" rel="noreferrer">hibernate.connection.autocommit</a> which can be set to true. </p>
<p>But in the API, they have mentioned that it is not recommended to set it like so:</p>
<blockquote>
<p>Enables autocommit for JDBC pooled connections (it is not
recommended).</p>
</blockquote>
<p>Why is it not recommended ?
What are the ill-effects of setting this property to true ?</p>
| 0non-cybersec
| Stackexchange |
I'm a 24 year old female, my boyfriend who is 25 just broke up with me. What do I do?. The 24th of this month would have been our 4 year anniversary, two days ago we were happy and in love. Then his best friend and his girlfriend get a loan to get a house, and all of a sudden he broke up with me.
2 flipping days to change his mind about a 4 year relationship.
I'm lost and I don't know what to do, so what do I do? | 0non-cybersec
| Reddit |
Python help. So I have learn the basics of python but for the wrong reason. I was going to get into game hacking, but later on I learned that game hacking with python is quite difficult. I might learn C++/# later on, but for now, what can I do with python? I want to widen my knowledge on hacking. Anything from small to big, any suggestions? | 1cybersec
| Reddit |
What "black market" existed in your school?. | 0non-cybersec
| Reddit |
The moment. | 0non-cybersec
| Reddit |
Honey fried bananas over vanilla ice cream [2444×2444]. | 0non-cybersec
| Reddit |
JS array concatenation for results of recursive flattening. <p>Good day!</p>
<p>Task would be to get a flat version of an array, that may include some amount of nested arrays as well as other elements. For input <code>[1, [2], [3, [[4]]]]</code> output <code>[1, 2, 3, 4]</code> expected.
<em>FreeCodeCamp spoiler alert.</em>
Naturally, recursive solution comes to mind, e.g.:</p>
<pre><code>function steamrollArray(arr) {
var result = [];
for(var i = 0; i < arr.length; i++){
//part of interest
if (Array.isArray(arr[i])){
var nestedElements = steamrollArray(arr[i]);
for(var j = 0; j < nestedElements.length; j ++){
result.push(nestedElements[j]);
}
//</part of interest>.
} else {
console.log("pushing: " + arr[i]);
result.push(arr[i]);
}
}
return result;
}
</code></pre>
<p>And it does it's thing. Result of sample run would be:</p>
<pre><code>pushing: 1
pushing: 2
pushing: 3
pushing: 4
[1, 2, 3, 4]
</code></pre>
<p>And the question is: what goes awry, when we use concat to add <code>nestedElements</code> (that supposedly store return result of recursive call). If we are to change first <code>if{}</code> block in <code>for</code> loop (marked as part of interest) with snippet below:</p>
<pre><code>if (Array.isArray(arr[i])){
var nestedElements = steamrollArray(arr[i]);
result.concat(nestedElements);
} else {
</code></pre>
<p>we will observe the following result: </p>
<pre><code>pushing: 1
pushing: 2
pushing: 3
pushing: 4
[1]
</code></pre>
<p>My understanding was to pass the result of each recursive call to the <code>concat</code> function, which will add the returned array to the result, but for some reason it's not the case.
Questions on this task was asked, like <a href="https://stackoverflow.com/questions/30582352/flatten-nested-arrays-using-recursion-in-javascript">this one</a>, but those concerned with the flattening algorithm part, which is not questioned here.
I still fail to see the answer what exactly causes the difference. It very well might be something I simply overlooked in a hassle or as a result of my limited experience. Sorry if that's the case. </p>
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Finding the complexity of a recursive method. <p>An assignment question asks me to find the complexity of a [tail] recursive algorithm, copied below. While I understand all the complexity specifics, for example that the while loop's complexity is $n-1$ and the complexity of setting $j$ to $0$ is 1, I don't understand how I could trace the code recursively, that is within itsel - it's too hard to keep track of. </p>
<p>What I tried doing, is turning the algorithm into an iterative one, by simply putting all the code into a big while loop and thus avoiding the recursive call. But I'm not sure if this affects the complexity of the original algorithm.</p>
<pre><code>Algorithm MyAlgorithm(A, n)
Input: Array of integer containing n elements
Output: Possibly modified Array A
done ← true
j ← 0
while j ≤ n - 2 do {
if A[j] > A[j + 1] then {
swap(A[j], A[j + 1])
done:= false
}
j ← j + 1
end while
j ← n - 1
while j ≥ 1 do
if A[j] < A[j - 1] then
swap(A[j - 1], A[j])
done:= false
j ← j - 1
end while
if ¬ done
MyAlgorithm(A, n)
else
return A
</code></pre>
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NFL Front Pages: Championship Sunday. | 0non-cybersec
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Default methods in Java interfaces: How to JavaDoc?. <p>I checked several default methods in JDK 8 interface (like Function#compose(Function)) to learn how to document the default implementation of a interface method.</p>
<p>As far as I can see the JavaDoc does not refer to the default implementation but only to the general description of the interface method.</p>
<p>What is the expectation of users of an API? Where would they look for that kind of documentation?</p>
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| Stackexchange |
Nvidia Geforce GT630 resolution problem. <p>I installed the drivers but the maximum resolution I can get is 1360x768. Can I get to 1920x1080? On Windows it worked fine.
Edit: I have Ubuntu 12.04.2 LTS</p>
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| Stackexchange |
Balotelli's nonchalant shoulder goal from the weekend.. | 0non-cybersec
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Pixel 4XL Hands on. | 0non-cybersec
| Reddit |
Canon 7D V2.0 firmware posted on USA site! . http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_7d/#DriversAndSoftware
As reported by DPReview, some of the new features:
Improved maximum burst for RAW images (up to 25)
In-camera RAW image editing
In-camera Image Rating
In-camera JPEG resizing
Maximum Auto ISO setting (ISO 400-6400)
Manual audio level adjustment in movie recording
GPS compatibility
File name customisation
Time zone settings
Faster scrolling of magnified images
Quick control screen during playback
Download only available from link above (pre-announcement page has not yet been updated)
EDIT: Full list of new features: http://cpn.canon-europe.com/content/news/firmware_update_to_enhance_EOS_7D.do
EDIT: There's a video: http://web.canon.jp/imaging/eosd/samples/eos7d/firmware.html
EDIT: pick OSX Lion even if you run Mountain Lion, or you will not see the update. The DMG download doesn't have an installer, just copy the FIR to your CF card and follow instructions. | 0non-cybersec
| Reddit |
How to use spot instance with amazon elastic beanstalk?. <p>I have one infra that use amazon elastic beanstalk to deploy my application.
I need to scale my app adding some spot instances that EB do not support.</p>
<p>So I create a second autoscaling from a launch configuration with spot instances.
The autoscaling use the same load balancer created by beanstalk.</p>
<p>To up instances with the last version of my app, I copy the user data from the original launch configuration (created with beanstalk) to the launch configuration with spot instances (created by me).</p>
<p>This work fine, but:</p>
<ol>
<li><p>how to update spot instances that have come up from the second autoscaling when the beanstalk update instances managed by him with a new version of the app?</p>
</li>
<li><p>is there another way so easy as, and elegant, to use spot instances and enjoy the benefits of beanstalk?</p>
</li>
</ol>
<p><strong>UPDATE</strong></p>
<p>Elastic Beanstalk add support to spot instance since 2019... see:
<a href="https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/elasticbeanstalk/latest/relnotes/release-2019-11-25-spot.html</a></p>
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Two way tie and three way tie at Phillips 66 Nationals in the 100 Backstroke. | 0non-cybersec
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