Provided are a method, system and program for maintaining and using information on updates to a data group after a logical copy is made of the data group. A first logical copy of a data group in a storage at a first point-in-time is established. The first logical copy maintains data to reconstruct the data group as of the first point-in time after the data group has been updated following the first-point-in time. Indication is made of regions of the data group updated at the storage after establishing the first logical copy. A second logical copy of the data group in the storage at a second point-in-time is established. The second logical copy maintains data to reconstruct the data group as of the second point-in time after the data group has been updated following the second point-in time. The indicated regions of the data group updated between the first and second points-in-time are saved in a change list.

1. Field of the Invention
The present invention relates to a method, system, and program for maintaining and using information on updates to a data group after a logical copy is made of the data group.
2. Description of the Related Art
Backup programs backup data at a computer system to a backup storage device, which may comprise a local storage device or remote storage device. Certain backup programs provide management of the backed up files and may utilize a backup database having information on the status of backed-up files. Such managed backup programs typically store the data in a proprietary storage format and utilize complex backup client and backup server programs to manage the backup operations in a network environment. The managed backup program must be used to restore the files maintained in the proprietary backup format.
In addition to maintaining back-ups of data, certain copy programs create logical copies or an image of a volume instantly, without having to physically copy the data subject to the copy operation. After the logical copy is established, any updates to the data subject to the logical copy operation are moved to the logical copy before the update is applied to allow return to the data as of the point-in-time the copy was created. Snapshot copy is a copy program offered by different software vendors that is used to create an instantaneous logical point-in-time copy of data.
Certain backup environments employ the use of distributed storage devices, which may be in different locations, to maintain backup copies of data. Although it may be desirable to have a remote machine maintain the logical copies of a backup data group, the logical copies and accompanying data structure of the data group created on one machine may not be useable on another machine with the same or different logical copy program, e.g., Snapshot program.

Maintaining and using information on updates to a data group after a logical copy is made of the data group


Methods of inspecting cellular articles such as cellular ceramic articles are disclosed, wherein the methods comprise characterizing a web structure from intensity values of a digital image. One method comprising establishing an edge location for each of the walls of the web, and an edge intensity slope SE for each edge location, and then searching for a wall intensity slope SW in one of the web walls of the characterized web structure to determine the location of a web defect. Another method involves determining at least one characteristic that defines a conforming cell, then identifying a non-conforming cell region based on the at least one characteristic, and then examining the walls within the non-conforming cell region to locate the defect in one of the walls within the non-conforming cell region.

Cellular ceramic articles are used as particulate filters and catalytic converters in cleaning exhaust streams and gas streams. The cellular ceramic articles have a web made up of finely formed walls that define a dense array of cells. The web provides a relatively large surface area for catalytic material to react with the exhaust gases that pass through the cells.
In some applications the cellular ceramic article must have sufficient mechanical and thermal integrity to withstand impact and thermal requirements. It can be advantageous to have webs without defects such as breaks in the walk or missing wall sections, sometimes referred to as "non-knitters."

Methods for inspecting cellular articles


The vertical tailplane of the aircraft is equipped with a distress beacon. The floatability of the vertical tailplane is taken advantage of in order to keep the distress beacon on the surface of the water in the case of an accident caused by a forced landing on the sea.

The invention relates to the field of distress beacons installed on aircraft, these beacons also being known by the English acronym ELT (Emergency Locator Transmitter).
The invention more particularly relates to the improvement of the locating of an aircraft in the case of an accident caused by a forced landing on the sea.
It applies more particularly, but not exclusively, to the field of commercial aircraft.
Existing aircraft are equipped with a distress beacon which makes it possible to locate them in the case of an accident. Usually, in the case of a rapid deceleration or of an impact, this beacon typically transmits a 406 MHz radio signal which is detected by geostationary satellites.
This beacon is generally installed in the fuselage of the aircraft and has an external antenna for the transmission of the radio signal. This type of arrangement correctly meets the requirement in the case of an accident on land.
On the other hand, in the case of a forced landing on the sea, the aircraft often sinks rapidly. The distress signal is then taken with the aircraft towards the seabed. If the fuselage lies at a great depth, the signal transmitted by the beacon may not be powerful enough to reach the satellites. It then becomes difficult to locate the approximate position of the aircraft.
There is therefore a desire to improve the locating of an aircraft is the case of an accident caused by a forced landing on the sea.

Distress beacon integrated in the vertical tailplane of an aircraft


An assembly for enabling continuous seat post function during extreme conditions is described and includes: a first valve at least partially, slidably disposed within a stationary piston and for controlling a first fluid pathway there through, wherein the first fluid pathway runs from a first portion and to a second portion of the oil chamber, wherein the stationary piston separates the oil chamber into the first portion and the second portion; and a second valve at least partially disposed within the stationary piston and disposed in series with the first valve and having a second fluid pathway disposed through the first valve and the second valve, being in parallel with the first fluid pathway, running from the first portion to the second portion of the oil chamber, and providing a bypass for oil to flow from the first portion to the second portion when the first fluid pathway is closed.

Field of the Invention
Embodiments generally relate to a seat support assembly for a vehicle. More specifically, embodiments of the invention relate to a height adjustable seat support.
Description of the Related Art
A conventional seat post for a bicycle includes a suspension system that comprises an upper post telescopically positioned within a lower post. Within the upper and lower posts are positioned at least an oil chamber and a gas chamber sealingly separated by an internal floating piston (IFP). The conventional suspension system further may include an adjustable piston rod connected to a main piston, wherein the main piston divides the oil chamber into portion "A", that portion of the oil chamber closest to the seat saddle, and portion "B", that portion of the oil chamber closest to the gas chamber. These conventional seat posts are adjustable upon the actuation of a lever mechanically and/or remotely connected with the piston rod. The movement of the piston rod ultimately results in the opening and closing of flow ports within the main piston.
During times of extreme conditions (e.g., high temperatures, sudden changes in terrain, etc.), the portion "A" of the oil chamber furthest away from the IFP may experience an increase in pressure that causes a condition commonly known as hydrostatic lock. The term, "hydrostatic lock", generally is understood to describe a condition in a suspension in which a volume of an incompressible fluid exceeds its maximum available volume in which it resides; such a condition may render surrounding components at least temporarily non-functional.
Therefore a need exists for a seat post that avoids hydrostatic lock conditions during extreme conditions.

Infinite adjust seat post with pressure relief valve


A pattern forming method includes determining an allowable value of an etching conversion difference, obtaining a maximum distance between patterns generating the etching conversion difference within the allowable value, the patterns including main patterns or both main patterns and a dummy pattern, preparing a first design layout in which a first distance between the main patterns is smaller than the maximum distance, or a second design layout in which a second distance between the main patterns and the dummy pattern is smaller than the maximum distance, performing a design data conversion based on the first or second design layout to form first or second design data, and forming the main patterns by using the first design data, or forming both the main patterns and the dummy pattern by using the second design data.

1. Field of the Invention
The present invention relates to a pattern forming method and a semiconductor device manufactured by using the pattern forming method.
2. Description of the Related Art
In recent years, the technology of manufacturing a semiconductor device has progressed to arrive at the stage that a semiconductor device having a minimum processing size of 0.18 μm can be manufactured nowadays on a mass production basis. This prominent miniaturization has been achieved by drastic progress in fine pattern forming technologies such as mask processing technology, photolithography technology and etching technology.
In the era when the pattern size was sufficiently large, a planar shape of a desired LSI pattern was depicted as it was on a wafer as a design pattern so as to form a mask pattern having a high fidelity to the design pattern, and the mask pattern was transferred onto the wafer by a projecting optical system, followed by etching the underlying layer, thereby forming a desired LSI pattern substantially equal to the design pattern on the wafer.
However, with progress in the miniaturization of the pattern, it has been rendered difficult to form a pattern with high fidelity in each process, giving rise to the problem that the final finish pattern fails to conform with the design pattern. Particularly, in the lithography and etching processes, which are most important for achieving fine processing, a pattern layout arranged in the periphery of a desired pattern, i.e., the peripheral pattern environment, greatly affects the dimensional accuracy of the desired pattern.
Under the circumstances, proposed in, for example, Jpn. Pat. KOKAI Publication No. 9-319067 are an OPC (Optical Proximity Correction) technology, a PPC (Process Proximity Correction) technology, etc., in which a dummy pattern is imparted in advance to a design pattern for forming the size after the processing in a desired pattern so as to suppress the influence described above. The OPC technology noted above denotes the technology for correcting the change in size generated in the lithography process by a pattern. On the other hand, the PPC technology noted above denotes the technology for correcting not only the change in size generated in the lithography process but also the change in size generated by the mask and the etching process by a pattern.
In the case of employing OPC technology, it is certainly possible to suppress the process conversion difference, i.e., the difference between the resist size and the design size, derived from the pattern environment in the lithography process to a low level. However, even in the case of employing PPC technology, it was impossible in some cases to suppress completely the process conversion difference, i.e., the difference between the size after the etching and the resist size, derived from the pattern environment in the etching process. The process conversion difference in the etching process was generated mainly by two factors.
First of all, the process conversion difference was generated by the etched area in a large region hundreds of times as large as the region of the entire chip or the minimum pattern size that was to be processed. The technology of arranging a dummy pattern differing from a main pattern for controlling the area to be etched is disclosed in, for example, Japanese Patent Disclosure No. 2-236549, Japanese Patent Disclosure No. 3-180041, and Japanese Patent Disclosure No. 4-130709. In each of these prior arts, a dummy pattern is formed around a pattern that is to be processed in order to make the area to be etched within the chip as uniform as possible. In Japanese Patent Disclosure No. 3-180041 referred to above, a dummy pattern is arranged on an element separation region alone. On the other hand, in Japanese Patent Disclosure No. 4-130709 referred to above, a dummy pattern is arranged around an isolated pattern.
The second factor is the etching process conversion difference generated by only the distance between the pattern to be processed and the adjacent pattern. To be more specific, when a pattern is arranged in an isolated manner, the process size of the pattern after etching is rendered larger than the resist size after the lithography process. In order to suppress the conversion difference, it is necessary to make the size of the resist formed by the lithography process smaller than the desired size in view of the conversion difference generated in the etching process. However, the process margin that can be ensured by the lithography process is very small, with the result that it is very difficult to form a resist pattern smaller than the desired size and to ensure a required process margin. In other words, even in the case of employing PPC technology, it is very difficult to correct the increase in size in the isolated pattern derived from the etching process.

Pattern forming method and semiconductor device manufactured by using said pattern forming method


The present invention relates to a method for manufacturing a zirconia block for a dental prosthesis having a layered color gradient by a water absorption rate, in which the permeation degree of a coloring solution is controlled by setting a different particle size of powder for each layer of the zirconia block on the basis of the property that the amount of water absorption per hour is differentiated according to the particle size of powder, and as a result, the zirconia block is constituted so as to realize an esthetically excellent resultant product with the same color as natural teeth without carrying out the existing coloring liquid process for zirconia.

Recently, a material for a dental prosthesis has been replaced with zirconia which is excellent in biocompatibility, similar to natural teeth in appearance, excellent in aesthetic properties, and improved in durability due to high mechanical properties.
Meanwhile, the most important thing when a dental prosthesis is manufactured using zirconia is to improve aesthetic properties by applying a color gradient to zirconia, such that the dental prosthesis has a color corresponding to that of natural teeth. In the related art, a color gradient is applied on the basis of the color guide, and a work process called a coloring liquid for zirconia is further included in order to induce a more natural color gradient. Here, the coloring liquid for zirconia refers to a method of applying a different color to each part of a zirconia block.
As an example of the existing methods, Korean Patent No. 10-4142805 "Method for manufacturing color zirconia block endowed with aesthetic properties" is described.
In the related art, there is a method in which each site of a zirconia block is immersed in a large number of coloring solutions prepared for inducing the color gradient of teeth from light color to dark color, and then the coloring solution is implanted by applying heat thereto, and as another method, zirconia powder is introduced into each coloring solution having a different color, and then the coloring solution is permeated into the powder by applying heat thereto, the powder permeated with the coloring solution is brought out of the coloring solution and dried, and then a zirconia block having a color gradient is produced by injecting the powder into a pressurization device to pressurize the powder on the basis of the color guide.
Here, the disadvantage of the related art is that all the parts of the zirconia block are all composed at the same water absorption rate, so that it is inconvenient for an operator to color each part while replacing the coloring solution.
In order to eliminate the inconvenience of the coloring liquid working process for zirconia, Korean Patent No. 10-1276816 "Method for manufacturing zirconia block for artificial teeth having color gradient" has been proposed.
The related art is a method for producing a zirconia block having a color gradient by, separately preparing a colored zirconia powder and a white zirconia powder to mix the powders, blending the white zirconia powder with the colored zirconia powder at different weight ratios to prepare a plurality of raw materials showing different colors, injecting the raw material into a mold for compression molding in order of light color to dark color or dark color to light color, and then pressurizing the raw material.
However, since the method in the related art requires an advanced technology in which the colored zirconia powder and the white zirconia powder need to be prepared at different weight ratios, the aforementioned method incurs a problem in that the productivity is remarkably reduced by personnel costs, production costs, and the like.
Therefore, there is an urgent need for a method for manufacturing a zirconia block, in which the zirconia block may be prepared readily and rapidly and have a constant color gradient by applying a color gradient corresponding to that of natural teeth to a zirconia block, and improving an existing coloring liquid method for zirconia which is complicated and inconvenient and a method for mixing colored and white zirconia powders.

Method for manufacturing zirconia block for dental prosthesis having layered color gradient by water absorption rate


A method and apparatus is disclosed for controlling the sampling of a composite analog color video signal so that the analog signal is sampled at precise locations relative to the phase of the color subcarrier of the color video signal in the absence of modulation. The invention thereby enables a digitized signal having a constant phase relationship relative to the unmodulated subcarrier phase to be provided which can be advantageously used in magnetic recording and reproducing apparatus. Since the constancy of the location of the samples relative to the phase of the color burst is maintained prior to recording, there is no phase error that would pose a problem during reproducing of the signal. The apparatus stores a set of reference samples of a selected number of cycles of the color burst interval of the color video signal and generates an output clock signal that is phase synchronized with the reference samples, subsequently stores sets of comparison samples of color burst cycles from subsequent horizontal video lines using the generated clock signal and detects any error in the phase location thereof. The apparatus adjusts the phase of the generated output clock signal in response to any detected error signal and stores a new set of reference samples in the event that the error detected is beyond predetermined limits.

The present invention generally relates to a method and apparatus for taking samples of an analog television signal that is particularly suited for use in a magnetic recording and reproducing apparatus.
As is comprehensively set forth in our copending patent application Ser. No. 117,428, a digital recording and reproducing apparatus is disclosed which has many significant advantages compared to most commercial quality television broadcasting recording and reproducing apparatus which record and reproduce FM signals. In our aforementioned application, pluse code modulated digital video signals are recorded and reproduced. The digital recording and reproducing apparatus has, when compared to FM recording and reproducing, the desirable attributes of virtually eliminating banding and Moire of any nature from any cause, reducing chroma and luminance noise to a value better than -54 db, relaxing mechanical tolerances for quadrature adjustments in a quadruplex format recording apparatus by a factor of about 100 and providing an inherent time base error that is no greater than about 1/2 nanosecond.
The present invention also enables the aforementioned recording and reproducing apparatus to eliminate the problem of cycle hops which is present in conventional video tape recorders, for the reason that the decision for making the zero crossing selection for sampling the television signal is precisely determined with respect to the location of a horizontal synchronization pulse which is generated and which is precisely defined with respect to color burst phase and therefore the phase of the unmodulated color subcarrier and this is done before recording so that consistent reliable reproducing can be achieved.
The present invention is also broadly applicable to information signals other than a composite color television signal provided that the information signal is of the type which has a time-base synchronizing component. Such signals are used in wideband telemetry systems wherein the wideband telemetry signal has a pilot signal that represents the time-base synchronizing component.

Fast acting phase shifting apparatus for use in digital sampling systems


This invention relates to base ester compounds and complex ester compounds that can be used as a base stock for lubricant applications or a base stock blend component for use in a finished lubricant or for particular applications, and methods of making the same. The base ester compounds and complex esters described herein comprise dimer and/or trimer esters, and their respective branched derivatives.

Lubricants are widely used to reduce friction between surfaces of moving parts and thereby reduce wear and prevent damage to such surfaces and parts. Lubricants are composed primarily of a base stock and one or more lubricant additives. The base stock is generally a relatively high molecular weight hydrocarbon. In applications where there is a large amount of pressure applied to moving parts, lubricating compositions composed only of hydrocarbon base stock tend to fail and the parts become damaged. To make lubricants, such as motor oils, transmission fluids, gear oils, industrial lubricating oils, metal working oils, etc., one starts with a lubricant grade of petroleum oil from a refinery, or a suitable polymerized petrochemical fluid. Into this base stock, small amounts of additive chemicals are blended therein to improve material properties and performance, such as enhancing lubricity, inhibiting wear and corrosion of metals, and retarding damage to the fluid from heat and oxidation. As such, various additives such as oxidation and corrosion inhibitors, dispersing agents, high pressure additives, anti-foaming agents, metal deactivators and other additives suitable for use in lubricant formulations, can be added in conventional effective quantities. It has long been known that synthetic esters can be used both as a base stock and as an additive in lubricants. By comparison with the less expensive, but environmentally less safe mineral oils, synthetic esters were mostly used as base oils in cases where the viscosity/temperature behavior was expected to meet stringent demands. The increasingly important issues of environmental acceptance and biodegradability are the drivers behind the desire for alternatives to mineral oil as a base stock in lubricating applications. Synthetic esters may be polyol esters, polyalphaolefins (PAO), and triglycerides found in natural oils. Of key importance to natural oil derived lubricants are physical properties, such as improved low temperature properties, improved viscosity at the full range of operating conditions, improved oxidative stability (meaning removal of double bonds in the case of natural oil derived materials), and improved thermal stability.
Various prior art efforts have attempted to describe esters for use in biolubricant applications, examples of which include U.S. Patent Application No. 2009/0198075 titled Synthesis of Diester Based Biolubricants from Epoxides ("Ref. 1"); Synthesis and Physical Properties of Potential Biolubricants Based on Ricinoleic Acid, by Linxing Yao et al., Journal of the American Oil Chemists' Society 87, 2010:937-945 ("Ref. 2); Melting Points and Viscosities of Fatty Acid Esters that are Potential Targets for Engineered Oilseed, by Linxing Yao et al., Journal of the American Oil Chemists' Society 85, 2008,:77-82 ("Ref. 3"); Diesters from Oleic Acid: Synthesis, Low Temperature Properties and Oxidation Stability, by Bryan R. Moser et al. Journal of the American Oil Chemists' Society 84, 2007,:675-680 ("Ref. 4"); Oleic Acid Diesters Synthesis, Characterization and Low-Temperature Properties, by Jumat Salimon et al., European Journal of Scientific Research 32(2), 2009, 216-229 ("Ref. 5"); U.S. Pat. No. 6,018,063 titled Biodegradable Oleic Estolide Ester Base Stocks and Lubricants ("Ref. 6"); and Oleins as a Source of Estolides for Biolubricant Applications, by L. A. Garcia-Zapateiro et. al., Grasas Y Aceites, 61(2), 2010, 171-174 ("Ref. 7") (collectively, the "cited prior art"). However, none of the cited prior art references describe improved physical properties to the broad extent of the present invention.

Esters for use as a base stock and in lubricant applications


An optical assembly, a display device and a method for driving the same are provided. The optical assembly includes two substrates disposed opposite to each other, and electrodes are disposed on the two substrates respectively. Voltages are applied to the electrodes to form a transverse electric field being configured for driving liquid crystal molecules proximal to the substrates to deflect, so that liquid crystal proximal to the two substrates both form liquid crystal lenses, thereby forming a double-layer liquid crystal lens structure. Since the two substrates of a liquid crystal cell have high alignment accuracy, the electrodes on the two substrates are consistent in spatial distribution, thereby solving mura problem.

In smart display function applications, an anti-peeping display is an application having higher demand. However, a current anti-peeping mode is fixed and cannot be switched to a sharing mode. Since a liquid crystal lens may be controlled by an electrode to adjust light, the liquid crystal lens may be used for realizing automatic switching between the anti-peeping mode and the sharing mode, but mura may be generated.

Optical device, display apparatus and method for driving same


A system for powering a datacenter campus including a main direct current (DC) superconductor cable configured to receive direct current DC electrical power from an alternating current (AC) power grid through a AC-DC converter, a DC-DC hub connected to the main superconductor cable, and a plurality of secondary DC superconductor cables, wherein each secondary DC superconductor cable includes a first end electrically connected to the DC-DC hub and a second end electrically connected to server racks housed in a respective datacenter building of the datacenter campus.

High voltage applications, such as operating a large-scale datacenter, require high-voltage power to be provided from a high-voltage power source, such as a transmission grid. High-voltage power lines are typically used to connect the transmission grid to the datacenter.
Conventional high-voltage power lines have several disadvantages. High-voltage power lines require heavy and large conductive elements in order to carry power to the datacenter or other downstream loads. Additionally, in many places, the high-voltage power lines are conventionally routed above ground using overhead conductors. Placing the conductors above ground uses up valuable space, makes connection to underground datacenter buildings difficult, and increases the risk of electrical failure, such as due to storms or falling trees. Additionally, the sight of high-voltage power lines is generally unappealing, and some are concerned about radiation risks from exposure to the power lines.
In a datacenter campus, in which the datacenter is distributed among several buildings in a confined space, additional high-voltage power lines, branching elements, and switching elements, are needed to connect the transmission grid to each building. These elements all require large and heavy conductors that occupy significant amounts of space, despite the confined space available within the campus. Additionally, the size and weight of the power lines and conductors makes updating campus layout especially difficult if changes are desired to be made, such as adding a new building. Furthermore, running power lines to each of the buildings only increases unsightliness of the power distribution system and heightens exposure concerns.
Additionally, using high-voltage power lines to provide power to datacenters raises concerns over grid stability. Grid stability may be problematic at any time, but particularly when the datacenter load suddenly changes, and especially when the data center is connected to a weak transmission grid.

High voltage superconductors for datacenter campus


A control unit for a transmission control module of a motor vehicle transmission includes a circuit mounting device and at least one attachment device configured to attach the circuit mounting device to a carrier board. The circuit mounting device includes an electronic circuit and has a first bearing side with which it is configured to be pressed against a second bearing side of the carrier board by the attachment device. The attachment device has at least one attachment element which is connected to the circuit mounting device and protrudes with a first end from the circuit mounting device on the first bearing side. The attachment element is configured to project through an attachment opening in the second bearing side of the carrier board.

The present disclosure relates to a control unit for a transmission control module of a motor vehicle transmission having a circuit mounting device and at least one attachment device, wherein the circuit mounting device has an electronic circuit, and the attachment device is provided for attaching the circuit mounting device to a carrier board. The circuit mounting device has a first bearing side and can be pressed with the first bearing side against a second bearing side of a carrier board by means of the attachment device. The disclosure also relates to a transmission control module and to a transmission for a motor vehicle.
Transmission control modules are installed, for example, in the interior of transmissions, for example in automatic transmissions of motor vehicles. A transmission control module has in this context a control unit, various sensors, plugs, etc. During operation, the control unit generally heats up with the result that there is provision for heat to be conducted away. For this purpose, the control unit can bear against a heat-conducting board in order therefore to be able to conduct away heat. For example, the control unit can be pressed with a spring against a supporting board, wherein the spring can be attached to the supporting board and can be embodied as a spring clip. The spring can alternatively also be supported on a transmission component. Furthermore, the control unit can also be attached to a supporting board by means of a heat-conducting bonding agent. DE 196 00 619 A1 discloses, for example, a control unit in which a power component is pressed onto a printed circuit board by a spring element. However, it has become apparent that bonded connections of an oil-resistant design constitute a thermally conductive resistor and therefore cannot ensure optimum conducting away of heat. When there are spring clips, bending stress of the carrier board occurs, and when a spring is supported on a transmission face the pressing over a surface does not occur until the components are completely assembled. There is therefore a need to make available a way of attaching a control unit which is simpler and which ensures optimum conducting away of heat.

Attachment of a control unit for a transmission control module to a carrier board


A constant strain spring compensation device, mainly comprising the grooved pulley, compensation cable, left end plate, spindle, oil seal, bearing, right end plate, contact flat spiral spring, housing, fastening angle steel, mounting base, pin, and wire-breaking arresting device. Said grooved pulley is fixed on the spindle, said compensation cable is wound and one of its ends is fixed on the grooved pulley, and the other end is connected to exterior overhead contact lines. Said spindle is supported on left end plate and right end plate by using the oil seal and bearing. Said left end plate, right end plate, housing, fastening angle steel, and mounting base form a closed box base. Said pin is connected to the side of the mounting base remote from said box base. Said contact flat spiral spring is arranged within said box base with the inner end hook being connected to the spindle and the outer end hook being connected to the fastening angle steel of the box base. The constant strain spring compensation device of the present invention is compact, small in size and weight. It may maintain a certain strain on the overhead contact lines of electrified railway to reduce the contact loss rate of its pantograph.

The overhead contact lines (catenary cables, contact cables and flexible catenary spans) of an electrified railway affect both the height and strain of the contact suspension due to the shrinkage or expansion caused by variation in temperature and because of the elongation of elastic linear material caused by creep, wear of cable, etc., as well as the tilting of the supports due to long time use. These factors cause contact loss, and deteriorate the current-collecting capability of overhead contact lines, whilst increased strain could cause the breakage of overhead contact lines, which leads to operation faults of the overhead contact lines.
Overhead contact lines are arranged in sections. Each of the sections is called an anchor section, and is installed at both ends. In order to automatically keep a constant strain of the overhead contact lines, normally, strain compensation devices are provided at anchor points.
Existing strain compensation devices that are currently in use have mainly the following two forms.
1. Existing compensation devices set up on existing overhead contact lines (catenary cables, contact cables and flexible catenary spans) of an electrified railway are usually of the weights type, two kinds of which, namely pulley block and ratchet wheel are normally utilized. These two kinds of compensation devices have the advantages of having simple structures and high reliability in operation. However, they have also the disadvantages of being large in size, heavy in weight, ugly in appearance, and easy to swing and get struck in a strong wind. Another disadvantage is that they are expensive in terms of installation and maintenance. This is mainly caused by the need of supplementary structures to support, conduct and protect such compensation devices and the daily operation management and repair work involved. Particularly while reconstructing electrical contact lines and installing the weight in low and narrow spaces of, for example, an underground railway and an existing tunnel etc., it is necessary to expand the cross sections of the tunnel. This will result in significantly increasing the project quantities, disturbing the traffic, prolonging project time, and increasing project expenses. In a place of more complicated geological conditions, it is even hardly to carry out the project.
2. The flexible catenary span of electrified overhead contact lines is the horizontal support device of overhead contact lines suspension in a railway station yard with multiple tracks, which consists of supports situated along both sides of railway, horizontal catenary cables suspended from the support, upper and lower positioning cables and accessories which hold and connect them.
In order to improve the current-collecting capability of overhead contact lines and decrease operation maintenance of flexible catenary span, a compensation device is provided on upper and lower parts of the positioning cable. The compensation device may be basically adapted to the steadiness of the height of flexible catenary span, however, it has the disadvantages of being short in compensation anchor section, big in strain changes, small in elongation length, poor in performance.
The following several kinds of compensation devices existing in China and other countries do not have wide application due to their various disadvantages.
1. Compensation devices consisting of several cylindrical helical compression springs in series (for example: the elastic strain compensation device of Chinese Patent No. 200420025333.1, overhead contact lines elastic strain automatic compensation device of Chinese Patent No. 200510038827.2): since the force of cylindrical helical compression spring adopted is directly proportional to the travel, such compensation device can not ensure the constancy of strain of the overhead contact lines.
2. Hydraulic or pneumatic type compensation devices (such as: a hydraulic compensation device for electrified railway of Chinese Patent No. 03235102.X, a differential plunger hydraulic strain compensation device of Chinese Patent No. 03218606.1, a pneumatic strain compensation device for electrified railway of Chinese Patent No. 0023267.2): due to the loss of oil or air, continuously monitoring and maintaining, and refilling oil or air are necessary. Since oil or air leaks occur frequently, their costs are higher and application thereof is restricted.

Constant strain spring compensation device


A liquid level sensor comprises a plurality of electrodes arranged in a defined relationship with respect to a container filling trajectory, a signal generator coupled to one or more of the plurality of electrodes, a signal receiver coupled to one or more of the plurality of electrodes, and a sensing circuit coupled to at least one of the signal generator and signal receiver. The sensing circuit is configured to produce an output indicative of electrical resistance between at least one pair of the plurality of electrodes. The sensing circuit may be associated with the signal receiver and/or with the signal generator.

1. Field of the Invention
The invention relates to liquid level sensors, and has especially advantageous application in a laboratory environment where small changes in liquid levels are to be measured.
2. Description of the Related Art
A wide variety of liquid level sensing methods have been proposed and employed. Mechanical methods have been employed wherein a buoyant element rides on the surface of the liquid and its position is detected. While simple to design and implement, these are difficult to miniaturize. The container has to be large enough to allow the floater to move up and down freely.
Acoustic methods have also been used in which an ultrasonic transmitter/receiver is used to launch a sound wave at the surface and detect its return. The beam spot of the sound wave is usually too large for the device to work reliably inside a small tube.
Pressure based sensing using a pressure transducer at the bottom of the container has been implemented wherein the liquid height is determined by measuring the pressure at the bottom of the container. These sensors do not work well for small volumes when surface tension becomes comparable to gravity.
Electrical schemes have also been devised. For example, the capacitance of a container may be measured to indicate fluid level. These types of detectors have been usually implemented as all-or-nothing type detectors, wherein the liquid rises to some pre-determined level, and the change is large enough to trip the detector. Another electrical scheme is described in U.S. Pat. No. 3,848,627 to Page. This device is intended to measure the water level in swimming pools, and includes a series of electrodes at different heights in a liquid filled tube. The lowermost electrode is grounded. A circuit is coupled to the remaining electrodes that energizes selected relay coils as the other electrodes change state between being grounded or electrically floating as the water level rises and falls.
None of these devices can detect small volumes at high resolution. Thus, an improved, reliable, and small size level sensor is needed.

Method for sensing levels of conductive liquids


A solenoid operated valve and method of assembly characterized by a threaded connection between the pole piece (69) and the cage (11), the threaded connection (75) including a first threaded connecting portion fixed in relation to the pole piece and a second threaded connecting portion fixed in relation to the cage and in threaded engagement with the first threaded portion such that relative rotation of the first and second threaded portions would vary the axial spacing between the proximal end of the pole piece and the valve seat (38) over a range of adjustment; and an anti-rotation device interposed between the first and second threaded connecting portions for locking the first and second threaded connecting portions against relative rotation to fix the axial spacing between the proximal end of the pole piece and the valve seat within such range of adjustment, which axial spacing regulates the maximum pressure that can be supplied to the control port (25).

Proportional pressure control valves heretofore have been used for a variety of applications including the control of clutches in an electro-hydraulic transmissions. In such electro-hydraulic transmissions, a hydraulic pump supplies pressurized hydraulic fluid for energizing a hydraulic actuator, for example a piston or a bellows, that directly operates the clutch. In one design for such a clutch, springs hold the clutch in its disengaged position and a carefully controlled pressure of the hydraulic fluid from the pump overcomes the springs' force to effect engagement of the clutch. When the hydraulic pressure is removed from this clutch, the springs once again move the clutch into its disengaged state.


A compound represented by the general formula (I) below:

Nucleic acids are the DNA and RNA that govern the genetic information of living creatures. On the other hand, a peptide nucleic acid (PNA) is a modified nucleic acid in which the sugar-phosphate skeleton of a nucleic acid has been converted into an N-(2-aminoethyl)glycine skeleton (FIG. 1). The sugar-phosphate skeletons of DNA/RNA are negatively charged under neutral conditions and exhibit electrostatic repulsion between the complementary strands, but since the backbone structure of PNA itself has no charge, there is no electrostatic repulsion. PNA therefore has a high duplex-forming ability and a high base sequence recognition ability in comparison with conventional nucleic acids. Furthermore, since PNA is very stable against in vivo nuclease/protease and is not decomposed thereby, its application in gene therapy as an antisense molecule has been investigated.
Modifying conventional techniques that employ DNA as a medium so that they can be used with PNA can compensate for the defects of DNA that could not be overcome previously. For example, it is possible to apply PNA to the "DNA microarray technology" that carries out a systematic analysis of a large amount of genetic information at high speed, and to the "molecular beacon" that has been developed recently as a probe that can detect by fluorescence a specifically recognised base sequence. Since these techniques use DNA as a medium, which has poor enzyme resistance, when employing these techniques it is necessary to carry out precise sampling. Satisfying this requirement is the key to enhancing the above-mentioned techniques.
On the other hand, since PNA is completely resistant to enzymes, the use of PNA as a replacement for DNA in the DNA microarray technology and the molecular beacon is anticipated to eliminate the defects of the above-mentioned techniques and to derive further advantages.
There are a large number of fields, in addition to the DNA microarray technology and the molecular beacon, that are anticipated to advance as a result of the use of PNA, and in these fields it is necessary to efficiently functionalise PNA, that is to say, to design a novel PNA monomer by the efficient introduction of a functional molecule to a PNA monomer.
Since methods for synthesising a PNA oligomer employ the commonly used solid phase peptide synthesis, PNA monomer units can be classified into two types in terms of the PNA backbone structure, that is to say, the Fmoc type PNA monomer unit and the tBoc type PNA monomer unit (FIG. 2).
A method for synthesising the Fmoc type PNA monomer unit has already been established, its oligomers can be synthesised by means of a standard automatic DNA synthesiser, and it can be synthesised on a small scale by the route below:
(X denotes guanine, thymine, cytosine or adenine.)
The first PNA employed the tBoc type PNA monomer unit as described below:
after which a more efficient synthetic method:
was established.
However, as described above, since the Fmoc type, which is easy to handle, has been developed, the use of the tBoc type is becoming less frequent.
However, when introducing a functional molecule other than the four nucleic acids guanine, thymine, cytosine and adenine, for example, when introducing a photofunctional molecule, since the functional molecule that is to be introduced is often unstable under alkaline conditions, the tBoc type PNA backbone structure, which does not employ alkaline conditions, is very useful. With regard to a "process for producing t-butoxycarbonylaminoethylamines and amino acid derivatives", there is already a patent application filed by the present inventors as Japanese Patent Application No. 2000-268638.
Other than the above process, 5 examples of the synthesis of a monomer unit for a photofunctional PNA oligomer are known. All these cases employ the above-mentioned route, but their yields are either not described or very low (Peter E. Nielsen, Gerald Haaiman, Anne B. Eldrup PCT Int. Appl. (1998) WO 985295 A1 19981126, T. A. Tran, R.-H. Mattern, B. A. Morgan (1999) J. Pept. Res, 53, 134-145, Jesper Lohse et al. (1997) Bioconjugate Chem., 8, 503-509, Hans-georg Batz, Henrik Frydenlund Hansen, et al. PCT Int. Appl. (1998) WO 9837232 A2 19980827, Bruce Armitage, Troels Koch, et al. (1998) Nucleic Acid Res., 26, 715-720, Hans-georg Batz, Henrik Frydenlund Hansen, et al.) Furthermore, since the structures of the compounds used have the characteristic of being comparatively stable under alkaline conditions, it is surmised that, when a chromophore that is unstable under alkaline conditions is present, an efficient synthesis by a method similar to the above-mentioned conventional method, that is to say, route A below, is not possible.

There is therefore a strong desire for the establishment of a technique that functionalises a PNA monomer efficiently as well as for the development of a functional PNA monomer such as, for example, a photofunctional PNA monomer.

Functional peptide nucleic acid monomer and process for producing the same

Abstract: In the formula, A is as defined in the specification and B denotes

Abstract: where n is an integer of 1 to 4, and a process for producing the above compound includes a reaction between an activated ester and a t-butoxycarbonylaminoethylamine or an ω-amino acid derivative.


A computationally efficient message verification strategy that achieves non-repudiation and resilience to computational denial of service attacks in conjunction with a broadcast authentication protocol that authenticates messages using a combination of a digital signature and a TESLA MAC. When messages are received at a receiver, the verification strategy separates the messages into messages with the same sender identification. The strategy then determines whether the TESLA MAC authenticator is valid for each message and discards those messages that do not have a valid TESLA MAC. The strategy collects the messages that have a valid TESLA MAC for each sender identification and performs a batch verification process on the group of messages to determine if the messages in the group have a valid digital signature. This strategy verifies each message in the group of messages if the batch verification process shows that the group of messages has a valid digital signature.

1. Field of the Invention
This invention relates generally to a system and method for authenticating a message transmitted in a wireless network and, more particularly, to a system and method for authenticating a message transmitted in a wireless network that employs both a digital signature and timed efficient stream loss-tolerant authentication (TESLA).
2. Discussion of the Related Art
Automotive active safety applications based on vehicle-to-vehicle (V2V) communications are a powerful service that can significantly reduce the number of automotive accidents, and related health care and insurance costs. Communications security is critical in these applications, since drivers of vehicles are expected to act in accordance with the warnings and advisories provided by the V2V applications. However, since communications security comes with both computational and bandwidth related overhead, it is important to reduce these overheads in order to obtain cost-effective implementations.
V2V safety applications, such as blind spot warning (BSW) and co-operative collision warning (CCW), rely on the repeated exchange of kinematical information between neighboring vehicles by V2V communications as per the wireless dedicated short range communication (DSRC) standard. These messages are typically transmitted periodically, at the frequency of 10 Hz per vehicle, and are authenticated using digital signatures based on an underlying public key infrastructure (PKI) in accordance with the IEEE 1609.2 standard specification. However, generating and verifying digital signatures consumes a significant amount of the share of the automotive processor. As the penetration of V2V-based active safety applications increases, there is a need for computationally efficient mechanisms for verification of messages since V2V-equipped vehicles would have to verify an increasing number of messages.
Each principal in a PKI system has a pair of keys, namely a private key and a public key. The private key is known only to the principal and the public key can be shared with other entities in the system. The keys can be visualized as a pair of functions Pr and Pu representing the private and public keys, respectively, and having the property M=Pr(Pu(M)) and M=Pu(Pr(M)), where M is the message that is to be secured using the keys. To ensure message integrity, the sender of the message signs the message with its private key, and adds this signature to the message. Upon receiving the message, the recipient can verify the signature of the message using the sender's public key.
Although the discussion herein pertains to V2V networking, the various broadcast authentication techniques have a much wider application. At an abstract level, the various broadcast authentication techniques discussed herein apply to communication networks where nodes broadcast information to one another in an authentic manner. In these networks, potentially every node is a sender and a receiver. Thus, a given node would broadcast its messages to multiple nodes, and it may also receive messages from multiple, and possibly different, nodes. It is desirable to conserve bandwidth in these types of communication networks. Bandwidth is consumed when the public key is sent ahead of the messages or packets. Additional bandwidth is also consumed when signatures are appended to messages or packets. It is also desirable to conserve the use of the vehicle computer or CPU for verifying received messages. If all nodes send messages at some rate, then a vehicle might receive many more messages as compared to how many it sends. Thus, generally, when computational overhead is referred to, the time taken for key generation and signature generation is ignored, and the process focuses only on the time taken for signature verification.
For the communications networks being discussed herein, the nodes would typically use an authentication protocol to achieve broadcast authenticity of the messages. An authentication protocol between a sender and a receiver enables the sender to send information to the receiver in an authentic manner. The authentication protocol used in the broadcast networks being discussed includes three steps, namely, key generation and public key distribution, signature generation and signature verification. For key generation and public key distribution, the sender executes a key generation algorithm for the authentication protocol and creates the public key, the private key and other variables. The sender then disseminates the public key to the receivers.
For signature generation, when the sender needs to send an authentic message, the sender creates the message and populates it with the appropriate information, and then uses a signature generation algorithm specific to the authentication protocol. In the case of digital signature algorithms, one public-private key pair can be used to sign a theoretically unlimited number of messages. The signature generation algorithm generally uses the hash-and-sign paradigm. This means that the message is first hashed into a constant length string of bits. The hashed version, also called the message digest, is then signed using the signature generation algorithm.
For signature verification, when a receiver needs to verify the authenticity of a received message, it needs to have in its possession the public key corresponding to the private key that signed the message. Assuming that the receiver does have the public key, it uses the signature verification algorithm for the authentication protocol. The verification algorithm also first hashes the message to derive the message digest, which is then subject to further verification steps.
At the security layer of the PKI protocol, the primary functionality of the broadcast authentication protocol is to filter bogus messages, i.e., those messages with the correct format, but with an invalid signature or authentication tag. The security strength of the broadcast authentication protocol is measured in n-bits of security, i.e., an attacker needs to perform O(2n) operations in order to forge a signature or authentication tag on a message. The IEEE 1609.2 standard recommends 128-bits of security.
While message authentication is sufficient to develop misbehavior detection algorithms at the application layer, non-repudiation is a required attribute to report misbehaving entities to the certifying authority (CA) in a PKI-based V2X (vehicle-to-infrastructure) security architecture. Note that the eventual eviction of misbehaving entities occurs via entries in a certificate revocation list (CRL) disseminated by the CA.
To verify whether a message is genuine or bogus consumes computational resources at a given node. In the wireless context, it is easy for a malicious entity without access to compromised keying material to create a bogus message, and inject those messages in the channel leading to a computational denial of service (DoS) attack. The notion of computational DoS resilience is introduced as the amount of computational work done by a receiver versus the amount of computational work done by the attacker. Unfortunately, digital signatures based on asymmetric key cryptography are particularly vulnerable to computational DoS attacks.
Note that broadcast authentication requires the asymmetric property that only the sender is able to generate the signature, or authentication tag, and any receiver is able to only verify the signature, or authentication tag. While asymmetric key cryptography can provide all the primitives required for broadcast authentication, primitives based on symmetric key cryptography are preferred because of their efficiency. Protocol constructions to attain broadcast authentication using symmetric key primitives include timed efficient stream loss-tolerant authentication (TESLA) and one-time signatures. In the vehicle ad-hoc network (VANET) context, however, these protocols piggyback on a PKI-based digital signature mechanism.
Persistent applications, such as BSW (Blind Spot Warning) or CCW (Cooperative Collision Warning), are based on vehicles transmitting on a continual basis, such as at the rate of ten messages per second. As vehicle densities increase, the rate of incoming messages to be verified increases linearly with the number of neighboring vehicles (assuming minimal losses in the wireless medium). However, the rate of outgoing messages to be signed is always bounded by the rate, such as ten messages per second. While it is possible to authenticate every outgoing message with a PKI-based digital signature, it may not be feasible to verify the digital signature of every received message at a node. Hence, the focus of efficient broadcast authentication is on efficient verification mechanisms. For example, consider 50 vehicles in the vicinity of a given tagged vehicle, each transmitting ten messages per second. The tagged vehicle receives up to 500 messages to be verified every second. Hence, for a stable system, the average verification time should be less than 2 ms.
There is an inherent asymmetry in the rate of incoming and outgoing messages in the context of a V2V network for active safety. Every V2V-equipped vehicle sends out a limited number of messages per unit time, but receives an increasing number of messages per unit time as the number of its neighbors increases. This asymmetry can be exploited by appending dual authenticators per message (one digital signature, and a lightweight authenticator). An authenticator is classified as lightweight based on the amount of time expended to generate or verify it. Nodes that come into the transmission range of the sender verify the digital signature at first, which enables them to verify the lightweight authenticator for subsequent messages.
As far as the problem of efficient broadcast authentication is concerned, there are various techniques available in the literature to address this problem. However, none of these available approaches is completely satisfactory. In particular, digital signatures result in high computational overhead, while one-time signatures, such as Merkle-Winternitz signatures, result in high communication overhead, and lightweight protocols, such as TESLA, result in delayed message authentication. Further, in one-time signatures, such as the Merkle-Winternitz signature, there is a trade-off between the computational overhead and the communication overhead, both of which increase in proportion with the number of bits being signed.
Suppose that for a given authentication mechanism, the average signing and verification times (in seconds) are denoted by Ts and Tv, respectively. Also, let Nout denote the rate at which the security layer receives outgoing messages to be signed per second, and let Nin denote the rate at which the security layer receives incoming messages to be verified per second. Since the utilization of the OBU (On-Board Unit) processor is at most 100%, it follows that for a stable system NoutTs+NinTv<1.
A brief description of the TESLA protocol is provided including its drawbacks in the vehicular context. This provides the motivation for modifications to the TESLA protocol for VANETs, which are then presented. The TESLA protocol is described in the context of a single sender and multiple receivers. The protocol is based on the delayed disclosure of symmetric keys. Initially, a sender appends to each message, a message authentication code (MAC) based on a symmetric key known only to itself. The receiver buffers the message without being able to authenticate them, which results in a message verification delay. A short time later, when the sender discloses the symmetric key, the receiver is able to authenticate buffered messages. The TESLA protocol is based on the property of loose time synchronization i.e., the receiver knows an upper bound on the sender's local time.
The sender divides time into L intervals of length TINT and computes a one-way hash-chain as described below. For a symmetric key K and a one-way hash function H(·), let H0(K)=K and let Hi+1(K)=H(Hi(K)) for integer values i≧0. The TESLA protocol also has a parameter called the key disclosure delay d expressed in units of the interval length TINT. At the start time T0, the sender computes the hash-chain, denoted by [K, H1(K), H2(K), . . . , HQ(K), . . . ] where Q>L. The sender decides on a time schedule to disclose symmetric keys of this hash-chain no earlier than the predetermined time instant.
The key disclosure schedule, denoted as ((T0, TINT, HQ(K)), signifies the sender's commitment to disclose the symmetric key HQ-w(K) no earlier than the time instant T0+w·TINT for all 1≦w≦L. Before time T0, the senders commitment to disclose symmetric keys is transmitted in an authentic manner to all receivers in a key disclosure schedule message. This key disclosure schedule message is signed with a digital signature, and requires support of the PKI security framework. All entities that have the key disclosure schedule ((T0, TINT, HQ(K)) follow the convention that interval w denotes the time interval [T0+w·TINT, T0+(w+1)·TINT. In accordance with the key disclosure schedule, the sender discloses the key HQ-w(K) during the interval w, for 0≦w≦L.
The transmission and reception processing is described at a node. When transmitting a packet, the sender adaptively selects a value of the key disclosure delay d. The sender discloses the symmetric key corresponding to the current time interval, and appends a MAC based on a symmetric key that will be disclosed d time intervals (of length TINT) later. Upon receiving a packet, the receiver:
1. Verifies the disclosed key is part of the hash-chain. The disclosed key is then used to verify buffered packers.
2. Determines the interval i in which the packet was transmitted based on the disclosed key in the packet, and an authentic version of the key disclosure schedule.
3. Based on its current time and a bound on the clock synchronization error, the receiver infers the latest possible interval x in which the sender could currently be in.
4. Determines the value of the parameters d in the message. If (x<i+d), the receiver buffers the packet for delayed verification. Otherwise, if (x≧i+d), it discards the packet as unsafe and drops it.
The primary advantage of TESLA is a significant improvement in the signing and verification time since the majority of messages are authenticated via a MAC based on a symmetric key. However, TESLA still requires support of the PKI-based security framework, since the key disclosure schedule has to be conveyed to all receivers in an authentic manner. In addition, TESLA requires clock synchronization at the nodes, and messages cannot be verified until the corresponding symmetric key is disclosed by the sender. Note that the parameters d and TINT of the TESLA protocol have to be carefully selected in order for the protocol to work well.
The main drawbacks of the TESLA protocols in the context of VANETs are described as follows. TESLA does not provide the non-repudiation property. While message authentication is sufficient to develop misbehavior detection algorithms at the application layer, non-repudiation is a required attribute for reporting misbehaving entities to the certifying authority (CA) in a PKI-based V2X security architecture. Note that the eventual eviction of misbehaving entities occurs via entries in a certificate revocation list (CRL) disseminated by the CA. DSRC (Dedicated Short Range Communications) channel switching between the control channel and service channel can also degrade the performance of TESLA.
V2X safety applications transmit real-time kinematic information (such as position, speed, and heading) in the message payload. Typically these messages are sent from the application layer to the security layer at the periodic rate of 100 ms. If TESLA key disclosure messages are always piggy-backed with application messages, then TINT=100 ms, where TINT denotes the length of the time intervals selected by the TESLA protocol. Hence, a lower bound on the message verification delay is 100 ms. This verification delay may be too large for V2X safety applications, such as collision avoidance applications. Note that a vehicle traveling at 90 kph (25 meters per second) would have moved 2.5 meters in 100 ms.
There are two types of potential attackers. An outside attacker that does not possess any compromised cryptographic credentials, such as private keys. The outside attacker can mount a DoS attack by sending bogus messages that have a valid format, but an incorrect authentication tag. This type of attacker steals a valid sender identification tag from the air, and transmits bogus messages on its behalf, overloading the receiving vehicles processor (buffers) for the computational DoS (memory DoS) attack. The other type of attacker is an inside attacker that has in its possession one or more compromised cryptographic credentials, such as the private keys. This type of attacker can transmit a spurious message, i.e., message with incorrect or invalid payload by cryptographically correct authentication tag(s). In the case of a transmitted message being authenticated by both a digital signature and a TESLA MAC, referred to as a TESLA authentication and digital signature (TADS) protocol, this type of attacker can mount a particularly insidious attack, referred to as a "correct MAC fake digital signature" attack. This type of attacker can mount a correct MAC fake digital signature DoS attack by transmitting messages with correct message authentication codes, but fake digital signatures. These messages can convey false information where the attacker does not get implicated if only the MAC is verified.

This patent is subject to a terminal disclaimer.

Efficient technique to achieve non-repudiation and resilience to DoS attacks in wireless networks


Techniques are described to collect data via a client device, such as a mobile phone. The data, referred to as “lifespace data,” comprises one or more measurements of an individual's functionality, a transmitter identification associated with a transmitter positioned in a discrete area (e.g., a room in a subject's residence), and a timestamp indicating when the transmitter identification was transmitted or received. One or more transmitters can be positioned in one or more discrete areas (e.g., throughout an individual's residence or workspace), with each transmitter configured to transmit a unique transmitter identification. In implementations, a transmitter comprises a Bluetooth beacon, and a transmitter identification comprises a Bluetooth identification number. The client device may be configured to provide the lifespace data to a server for storage, analysis, and intervention functionalities.

Reliable patient metrics are an important tool medical personnel employ to evaluate the mobility and overall activity of patients such as at-risk elderly individuals and individuals with psychiatric illnesses. For example, patient metrics may be used to measure how mobile a patient is after a medical procedure or to provide medical personnel with details of a patient's daily/weekly regimen. Patient metrics are generally acquired by medical personnel through the use of self-generated or caregiver-generated status reports. However, such status reports may at times not be an accurate or a current representation of the patient's mobility or overall activity.

Lifespace data collection from discrete areas

The Board of Regents of the University of Nebraska


A tree felling machine has a main pump for operating functions of the machine such as the drive wheels or tracks, the steering, the brakes, and the lifting and extension of the boom, and a separate saw pump for driving the cutting element, for example, a circular disc saw driven by a hydraulic motor. Both pumps are driven by the same prime mover, i.e. the same internal combustion engine, and the power division between the two pumps is determined by the operator and by the hydraulic control system. In particular, a control provided in the cab is controllable by the human operator to limit the maximum power that the saw pump can draw from the prime mover. In addition, the power that the saw pump can draw from the prime mover is limited by a combination of the displacement setting of the main pump, the output pressure of the saw pump, and the pressure exerted on the load by the main pump.

Tree fellers for cutting trees, called feller/bunchers if they have accumulating arms, are well known in the logging industry. In a typical arrangement, a disc saw is carried at the front of a boom of a back hoe type vehicle, that may be a tracked or wheeled vehicle, that has a gasoline or diesel engine. The engine typically drives two or more variable displacement hydraulic pumps, at least one of which is for the drive functions of the vehicle and the other of which is for turning the disc saw. In the past, the engine power useable to drive these two pumps has been determined by the characteristics of the pump and by the load to which the pump was subjected. The displacement of both pumps is manually controlled by the operator with suitable controls provided in the cab. Usually, the saw drive pump is operated at full displacement once the saw is brought up to speed, and the main pump displacement is controlled by the operator, depending on how fast the operator wants to operate the machinery or the loading placed on the machine by the various functions of the machine, with limits placed on it by the system so as not to overload the prime mover. However, there are times when it is desirable to limit the amount of engine power available to drive the saw, so as to make more power available for the other machine functions, such as driving the wheels or track in rough terrain, operating the clamp arms of the saw head in windy conditions, or operating the boom with a large load of trees held by the saw head, or while cutting a tree. This invention is directed toward a new way to divide power between the saw and main pumps in a tree felling machine.


A communication system for allowing personnel in a tunnel below ground to communicate with a location above ground includes a controller disposed below ground in the tunnel. The system includes an uplink portion that sends uplink messages from the controller below ground in the tunnel through earth to above ground. The system includes a downlink portion through which downlink messages are sent from above ground through earth to the controller below ground in the tunnel. The system includes a personnel communication portion through which downlink messages are sent from the controller wirelessly to the personnel as personnel messages and personnel messages are received wirelessly by the controller from the personnel below ground in the tunnel. A controller for allowing personnel in a tunnel below ground to communicate with a location above ground. A method for allowing personnel in a tunnel below ground to communicate with a location above ground.

This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the present invention. The following discussion is intended to provide information to facilitate a better understanding of the present invention. Accordingly, it should be understood that statements in the following discussion are to be read in this light, and not as admissions of prior art.
In mines, it is imperative that communication exists between the miners that are in the mine below ground and to people above ground. Specifically, in emergency situations, it is critical to be able to communicate with the miners to know whether they have been injured, where they are located, whether they are trapped, and whether they need food, water, air or first aid, to name but a few of the possible needs of the miners in such situations.
The problem that exists with communication in a mine is that the earth itself can impede communication between the miners in the mine as well as between the miners in the mine and people above the ground. Cabling or wiring has traditionally been used, but it requires a connection between the communication points. If the communication points are separated by a significant distance, it becomes problematic to extend the wiring such distances. Moreover, since mines are constantly expanding and changing shape, wiring is constantly being run to accommodate the changing distances and configurations of the mine. In addition, mines are hazardous places, with rockfall possibly damaging or cutting wires, which could be very dangerous in emergency situations where the communication is badly needed. Furthermore, it is impractical to extend wires to each miner in a mine to be able to communicate with each miner at any time. Although the specific need that gave rise to the invention was first identified in the mining industry, the utility of the invention could apply equally to emergency situations involving personnel in an underground work location, such as tunnels.
Wireless communication would eliminate the problems associated with using cabling or wiring for communication in a mine, but the very earth itself imposes difficulties on wireless communication between miners in the mine, and miners in the mine and people above ground.

Method, controller, and system for tunnel communication


A golfing putter comprises a shaft, a putter head and a pair of runner guides. The linearly elongated shaft is inserted at the rear of the putter head and disposed at angle to accommodate golfers seated in a wheel chair. The top of the putter head includes an alignment indicia, thereby providing a means for properly aligning the center of the putter face with the center of the golf ball and on the correct intended putting line. The pair of runner guides are positioned at the bottom of the putter head, intermediate to the putter head and the putting surface, and run parallel to the direction of the shaft and the intended putting line. The rearmost portion of the runner guides includes a rounded surface so as to elevate the putter face, thereby minimizing drag on the putter as it is stroked and encouraging overspin to the struck golf ball.

1. Field of the Invention
The present invention relates generally to putting devices used in golf, and, more particularly, to a putter a shaft inserted at the rear of a putter head and including a pair of guiding side members.
2. Description of the Related Art
As is well known in the art, a number of different kinds of golf clubs, and especially putters, are known. Relevant to these golf putters, the prior art can generally be grouped into two categories: putters having use-oriented aids and putting stroke training devices.
Putters having use-oriented aids are disclosed in the art as a means to assist the golfer in using a typical putter, or as an improved putter for use during a game of golf. For instance, an attachment to the shaft of a putter that aids in aligning the golf club at a right angle to a line between the ball and the hole. Others attach to the shaft of a putter and deploy to provide a guide for the putter user. The addition of an indicator surface allows for contrast with the putting surface and helps to avert the problem of the golfer""s eyes attempting to focus simultaneously on the ball, the club face, and the pointer of the putter guide concurrently and thereby losing sight of the pointer device.
Another problem that occurs from the use of a typical putter is the turning of the putter head while in use by the golfer. This putting error is caused by the imperceptible turning of the shaft of the putter as the head of the putter approaches or comes into contact with the ball. For example, and illustrating potential problems using a right-handed putter, the slight turning of the putter shaft may result in the toe of the putter passing ahead of the heel of the putter, thereby shutting the putter face and causing the line of the putt to start to the left of the target line. Conversely, slight turning of the putter shaft may result in the heel passing the toe, resulting in an opened putter face and causing the line of the putt to start to the right of the target line. Numerous attempts have been offered to correct this problem.
Other methods for eliminating putting errors caused by the turning of the putter shaft during use are known. For instance, a putter device that includes an internal spinning gyroscope device inside the putter head to provide sufficient momentum necessary to prevent any xe2x80x9cturningxe2x80x9d of the shaft when the putter head approaches or comes in contact with the ball. However, a putter made in accordance with such references is associated with several drawbacks, the most significant of which is that a putter made in such a manner would appear to not meet all of the requirements and rules of the U.S. Golf Association (USGA), the governing body and policy maker for professional and amateur golf in the United States.
Additionally, many putt-training devices are disclosed in the prior art that attempt to assist a golfer in developing proper, consistent habits that generally result from practice conducted with the proper information feedback.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention; however, the following references were considered related.
The following patents disclose the ornamental design for a golf putting head:
U.S. Pat. No. D 422,328 issued in the name of Lannoch;
U.S. Pat. No. D 422,041 issued in the name of Bradford;
U.S. Pat. No. D 421,471 issued in the name of Moldovan;
U.S. Pat. No. D 412,729 issued in the name of Woodward;
U.S. Pat. No. D 410,716 issued in the name of Bendo et al.;
U.S. Pat. No. D 408,878 issued in the name of Patten;
U.S. Pat. No. D 399,274 issued in the name of Bradford;
U.S. Pat. No. D 389,539 issued in the name of Moore;
U.S. Pat. No. D 385,324 issued in the name of Ubaney; and
U.S. Pat. No. D 367,909 issued in the name of Lee.
The following patents disclose the design and function for a golf putting training head:
U.S. Pat. No. 5,857,920, issued in the name of Hong, discloses a golf club for putting and driving a golf ball, wherein the club has a reflective surface to properly direct the alignment of a golfer""s eyes to an image of the ball, and also including a leveling device in the head of the club so as to indicate when the putter head is properly aligned in a horizontal orientation;
U.S. Pat. No. 5,458,332, issued in the name of Fisher, discloses a golf putter head with a cushion face, wherein the face of the putter receives a polyurethane insert or pad at a ball impact position;
U.S. Pat. No. 5,476,262, issued in the name of Bandiero, discloses a putter trainer having a substantially xe2x80x9cUxe2x80x9d-shaped head with a space provided between two sidewalls so as to receive a golf ball, thereby forcing a golfer to extend the putting follow through approximately five to eight inches in a straight line and providing a simulation of the proper follow through necessary to successfully putt;
U.S. Pat. No. 4,253,667, issued in the name of Clark et al, discloses a golf ball putter that distributes the mass of the putter head along the line of the putt because the putter shaft is connected to the putter head at a point centrally of the length and width of the head; and
U.S. Pat. No. 2,472,312, issued in the name of Parrish, discloses a putter directed to impart top spin to a struck golf ball, thereby eliminating the possibility of the golf ball drifting from the intended putting line, wherein the putter has a horizontally elongated head with a pair of legs vertically depending from the ends of the head down to the putting surface.
Consequently, a need has been felt for providing an apparatus and method of improving putting skills and assisting a golfer in practicing a number of aspects of putting. In particular, a need has been felt for providing a golf putter that accommodates disabled golfers, including golfers that require the use of wheel chairs. Golfers that use wheel chairs often have difficulty properly aligning themselves over the ball, and then making the traditional back-and-through pendulum-type putting stroke used by a majority of golfers. A putter having a rear mounted shaft disposed at an appropriate angle allows one in a wheel chair to position themselves behind the ball, and properly align the putter face and the ball with the golf hole along a more accurate line. Furthermore, the rear mounted shaft allows one to comfortably pull the club back and follow through, thereby averting the potential twisting and turning on the lower back that a standard pendulum putting stroke requires, which might be especially stressful on a person using a wheel chair.
It is therefore an object of the present invention to provide an improved golf putting apparatus.
It is a feature of the present invention to provide an improved golf putting apparatus including offering an alternative putting stroke, wherein the golfer stands facing the intended line of the putt and placing a back-and-through stroke on the putter.
It is a further feature of the present invention to provide an improved golf putting apparatus offering an alternative putting stroke to golfer""s that require the use of a wheel chair, thereby minimizing the twisting and turning of the back.
Briefly described according to one embodiment of the present invention, a golfing putter is provided comprising a shaft, a putter head and a pair of runner guides. The shaft is a linearly elongated shaft inserted at the rear of the puffer head and disposed at angle to accommodate golfers seated in a wheel chair. The top of the putter head includes an alignment indicia, thereby providing a means for properly aligning the center of the puffer face with the center of the golf ball and on the correct intended putting line. The pair of runner guides are positioned at the bottom of the putter head, intermediate to the putter head and the putting surface, and run parallel to the direction of the shaft and the intended putting line. The rearmost portion of the runner guides includes a rounded surface so as to elevate the putter face, thereby minimizing drag on the putter as it is stroked and impart overspin to the struck golf ball. To use the golfing putter, a golfer is positioned so that the golfer""s dominant arm (or putting arm) is substantially in line with the intended putting line. The user""s arm will grasp the shaft and align the putter face with the intended putting line. The user will then draw the shaft away from the golf ball and then push the shaft into and through the position of the golf ball and toward the golf hole. The putting motion is similar to the striking motions used in games like shuffleboard, billiards, slow-pitch softball or pitching horseshoes.
An advantage of the present invention includes reduction and/or elimination of wear and tear inflicted on putting surfaces caused by the need to realign the golfer when using a wheel chair.
Another advantage of the present invention is that it is specifically adapted for personal use because of the light weight components and the use of inexpensive materials.
Another advantage of the present invention is the reduction of lower back strain for a golfer using a wheel chair, eliminating the necessary reciprocating twists and turns required to perform a pendulum-type putting motion.
Yet another advantage of the present invention is the adaptability of the apparatus for use by persons having a variety of disabilities, including arm or leg amputation, blindness, paraplegia, or musculoskeletal disorders, among others.
Yet another advantage of the present invention is conformity of the present invention to the equipment guidelines established and enforced by the United States Golf Association (USGA), especially within the division that oversees the development and implementation of equipment for disabled golfers.


A rotating electric machine having a plurality of ventilating passages formed between a stator frame and a stator iron core, a cooler which cools a coolant is provided at least in one ventilating passage, communicating with a central portion of the stator iron core, of the plurality of ventilating passages, and a ventilating circuit in which the coolant cooled by the cooler is allowed to flow to the central portion of the stator iron core in a direction from an outer peripheral side to an inner peripheral side of the stator iron core via the at least one ventilating passage which communicates with the central portion of the stator iron core.

The present invention relates to a rotating electric machine in which a cooler for cooling a coolant is provided, as well as to a method of cooling a rotating electric vehicle.
A rotating electric machine in which a cooler for cooling a coolant is provided has been described, for example, in Japanese Patent Laid-open Nos. Hei 7-177705 and Hei 10-146022. The rotating electric machine described in these documents is configured such that a space between a stator frame and a stator iron core is partitioned into a low temperature gas chamber, to which a coolant at a low temperature is supplied, and a high temperature gas chamber, in which the heated coolant flows. A plurality of coolers distributed in the axial direction are provided in a foundation pit under the rotating electric machine, whereby the coolant cooled by the plurality of coolers and boosted by a ventilating fan is introduced to various heat sources, such as the iron core and the coils, via the low temperature gas chamber, and the coolant which has been used for cooling the heat sources is returned to the coolers via the high temperature gas chamber.
The above-described rotating electric machine, however, has a problem. Since the coolant which has passed through one or two or more of the heat sources is then introduced to a central portion of the iron core, the temperature of the coolant is raised before the coolant reaches the central portion of the iron core. Accordingly, for the above-described rotating electric machine, if a thermal load generated from the heat sources, such as the iron core and coils, becomes large with an increase in the generation capacity or in the loss density, the cooling effect of the coolant introduced to the central portion of the iron core is significantly degraded. As a result, in the above-described rotating electric machine, there is a possibility that local heat generation will occur in a gap between the stator iron core and a rotor iron core, thereby to increase the thermal oscillation stroke of the rotor due to uneven thermal expansion of the rotor in the axial direction.
To solve the above-described problem, there may be considered a method of increasing the amount of the coolant or optimizing the distribution of the amounts of the coolant components supplied to respective ventilating passages by adjusting the ventilating resistance; however, according to the former method, the ventilation loss of the coolant caused upon boosting the coolant by the fan becomes larger, to increase the total loss in the coolant; and, according to the latter method, since the ventilation resistance must be adjusted while the desired electric and mechanical characteristics are satisfied in a limited space, it is difficult to optimize the distribution of the coolant components supplied to the respective ventilating passages.
An object of the present invention is to provide a rotating electric machine which is capable of exhibiting a level axial temperature rise distribution, and a cooling method thereof.
The basic feature of the present invention is to supply a coolant, which is sufficiently cooled, to a central portion of an iron core which is most distant from both axial ends of the iron core. To realize this feature of the present invention, a plurality of ventilating passages, which continuously extend in the peripheral direction, are provided in the axial direction between a stator frame and a stator iron core, and coolers are provided in at least those passages, which communicate with the central portion of the iron core, of the plurality of ventilating passages formed in the axial direction, wherein the coolant boosted by a booster is cooled by the coolers and is allowed to flow to the central portion of the iron core in the direction from the outer peripheral side to the inner peripheral side of the iron core via the ventilating passages.
If an even number of ventilating passages are provided, two to four of the ventilating passages, which are located on the central side, constitute the ventilating passages which communicate with the central portion of the iron core. If an odd number of ventilating passages are provided, one to three of the ventilating passages, which are located on the central side, constitute the ventilating passages which communicate with the central portion of the iron core. The number of the ventilating passages is dependent on the capacity of the rotating electric machine. For example, for a generator having a generation capacity of 100 MW class, at least three ventilating passages are provided, and for a generator having a generation capacity of 350 MW class or more, seven to ten or more ventilating passages are provided.
According to the above feature of the present invention, it is possible to level the axial temperature rise distribution in the machine. In particular, the above feature is effective in a rotating electric machine in which the axial length is long and air is used as a coolant, for example, an air-cooled generator having a large capacity. Air which is larger in viscosity than hydrogen exhibits a high ventilating resistance when it flows in a generator, to thereby cause a temperature rise. The longer the ventilating distance of air, the larger the ventilating resistance will be. As a result, for a generator which is longer in axial length and larger in capacity, the temperature rise of the air becomes significantly larger, and the amount of the air supplied to the central portion of an iron core becomes smaller.
Accordingly, a small amount of air whose temperature is raised is supplied to the central portion of the iron core which is most distant from both the axial ends of the iron core, with a result that there occurs a difference in temperature between each of the axial ends of the iron core and the central portion of the iron core. According to the present invention, it is possible to supply a coolant which is sufficiently cooled to the central portion of the iron core, however, it is also possible to suppress the temperature rise of the central portion of the iron core to an allowable value or less, and, hence, to level the axial temperature rise distribution in the machine.
The leveling of the axial temperature rise distribution in the machine means that the temperature rise of the central portion of the iron core is suppressed to an allowable value or less, to reduce the difference in temperature between each of the axial ends of the iron core and the central portion of the iron core. Accordingly, there is no variation in the axial temperature rise distribution in the machine.


A valve mechanism for an acoustic modulator which modulates air flowing tugh the acoustic modulator. The valve mechanism comprises a pair of cylindrical shaped members with each member having a plurality of elongated ports. The first cylindrical shaped member is held in a fixed position, while the second cylindrical shaped member is movable with respect to the first member. There is located at the lower end of the second cylindrical shaped member a drive coil which is positioned in a magnetic field such that when the coil is excited by an electrical sinusoidal input signal, movement of the second member occurs, partially aligning the ports of the second member with the ports of the first member which opens the valve mechanism. The sinusoidal input signal causes a frequency "doubling" to occur, that is the valve mechanism of the present invention completes an open-close-open-close cycle during each cycle of the sinusoidal input signal. This frequency "doubling" modulation of air flow through the acoustic modulator is accomplished by exposing the same open port area for both the positive going portion and the negative going portion of the sinusoidal input signal. The valve mechanism "closes" when the sinusoidal input signal is at zero volts.

1. Field of the Invention
This invention relates generally to electro-mechanical modulators and, in particular, this invention relates to a valve mechanism for an acoustic modulator which modulates air flow passing through the valve at a selected frequency.
2. Description of the Prior Art
In the prior art there are many types of electro-mechanical modulators and choppers which regulate air flow at a selected frequency. One type of prior art electro-mechanical is an acoustic modulator which regulates air flow by creating air pressure variations which creates acoustic energy having a predetermined frequency. This acoustic energy may then be used to conduct noise and vibration testing on both civilian and military aircraft, missiles and other weapons systems.
The functioning part of the acoustic modulator is the valve mechanism. Prior art valve mechanisms generally use a pair of cylindrical shaped members, each member of which has a plurality of ports which when aligned allow pressurized air to pass therethrough. The first cylindrical shaped member is generally stationary and the second member, which is electro-magnetically exited, moves relative to the first member. An electrical sinusoidal input signal is provided to a coil which is positioned within a magnetic field and secured to the second member. This sinusoidal input signal excites the coil causing the ports of the second member to first align with the ports of the first member and then move out of alignment with the ports of the first member. This movement of the second member relative to the first member first increases air flow and then decreases air flow through the valve mechanism of the acoustic modulator which results in the acoustic modulator providing air pressure variations having a frequency equal to the frequency of the sinusoidal input signal.
Unfortunately, this prior art acoustic modulator consumes excessive air at partial modulation levels which is costly, provides excessive background noise and has a frequency response limitation of between 800 and 1000 hertz which is not an optimum desired frequency for vibration testing of military aircraft and the like.
A second prior art acoustic modulator used for testing purposes has a double valve mechanism of the type disclosed in U.S. Pat. No. 4,893,655 which issued Jan. 16, 1990. The double valve mechanism of U.S. Pat. No. 4,893,655 includes a pair of cylindrical shaped members with each cylindrical shaped member having a plurality of elongated ports. Electro-magnetic excitation causes the cylindrical shaped members to move relative to each other which causes the ports of the members to first align opening the valve and then move out of alignment closing the valve, thereby modulating air flow through the acoustic modulator. Linear motion of both cylindrical shaped members of the valve mechanism is only one half that of prior art valve mechanisms resulting in an acoustic output wave front which is twice the frequency of an electrical sinusoidal input signal supplied to the modulator.
While the valve mechanism of U.S. Pat. No. 4,893,655 provides a significant improvement in the frequency of modulation (approximately 2000 hertz) of air flowing through the modulator, this valve mechanism has a complex design, is expensive and is susceptible to failure because of the movement of both cylindrical shaped members of the valve mechanism.
With the disadvantages inherent in the design of prior art valve mechanisms for acoustic modulators, including those mentioned above, the present invention was conceived and one of its objects was to provide a valve mechanism for an acoustic modulator which modulates air flowing through the modulator at a frequency similar to that of the valve mechanism disclosed in U.S. Pat. No. 4,893,655.
Another object of the present invention is to provide a valve mechanism for acoustic modulators which is simplistic in design, highly efficient and still provides for a frequency of modulation approaching that of complex valve mechanisms such as the valve mechanism of U.S. Pat. No. 4,893,655.
These and other objects, advantages and novel features of the present invention will become more apparent from the detailed description of the preferred embodiment of the invention when considered in conjunction with the accompanying drawings.

Valve mechanism for an acoustic modulator

The United States of America as represented by the Secretary of the Navy