A method and system for a secure telephone protocol are disclosed, which can be implemented using current Voice over IP (VoIP) protocols, Session Initiation Protocol (SIP, as specified in the Request for Comment (RFC) 3261 from the Internet Engineering Task Force (IETF)), Real Time Transport Protocol (RTP, as specified in RFC 3550), and Secure RTP (SRTP, as specified in RFC 3711). The secure telephone protocol can include a shared secret value that is cached and then re-used later to authenticate a long series of session keys to be used for numerous separate secure phone calls over a long period of time, thereby providing cryptographic key continuity without the need for voice authentication. In an embodiment, the secure telephone protocol can utilize the Diffie-Hellman key exchange during call setup, and AES for encrypting the voice stream.

The well known Internet Protocol ("IP") provides a method for routing information over the Internet. Protocols for converting and routing voice conversations via any IP-based protocol are termed Voice Over Internet Protocol ("VOIP"). To date, most VOIP implementations have not been optimally secured.
One existing technology applicable to VOIP protection includes public key cryptography. The well known Diffie-Hellman ("DH") key agreement method exemplifies the type of public key cryptography that could be used in securing VOIP. DH includes all variants of DH, including, for example, the classic finite field DH ("FFDH") approach as well as the elliptic curve DH approach ("ECC-DH"). In addition, a public key infrastructure ("PKI") could be used. A PKI enables users of a public network such as the Internet to securely exchange information through the use of a public and private cryptographic key pair. In many approaches, security is enhanced by provisioning and sharing the key pair via a trusted authority. A PKI provides for digital certificates that can identify individuals or organizations. Unfortunately, PKI technology includes many complexities, including notions of a certification authority (CA), a registration authority (RA), one or more directories where the certificates (with their public keys) are held, and a certificate management system. The CA often is required to be a trusted entity that issues and verifies digital certificates. A digital certificate is an electronic data element that evidences an entity's credentials. The certificate can include the public key or information about the public key, as well as other information, such as a name, serial number, expiration dates, and a digital signature of the certificate authority. Digital certificates may be kept in registries so that authenticated users can look up other users' public keys.
Securing public switched telephone network ("PSTN") phones is well known. For example, the TSD 3600 from AT&T Corporation uses several of the techniques discussed in further detail below, including hash commitment and DH key exchange. Most secure phones rely on a DH public key exchange to agree on a common session key. For example, as shown in FIG. 1, User A 102 can use VOIP software 108 executing on computing device 106 to communicate with User B 104. User B uses bump-in-the-cord VOIP 112 with Ethernet-based phone 110. As shown in FIG. 1, DH is susceptible to a man-in-the-middle ("MitM") attack. In such an attack, MitM 130 intercepts communications from User A 102 to User B 104 and, in effect, carries on two different communications sessions—one with User A via device MitMA 132 and one with User B via device MitMB 134. In doing so MitM 130 makes it appear that User A 102 and User B 104 are communicating directly, when in fact MitM is secretly eavesdropping on their communication. Due to the possibility of the MitM attack shown in FIG. 1, a way to authenticate the DH exchange is commonly provided. Some systems accomplish this by depending on digital signatures backed by a centrally-managed PKI. The complexity of PKI, however, results in significant technology commitments, time requirements and budget commitments, both at initial deployment and during ongoing operations. A preferred alternative would be to avoid PKI altogether, especially when developing secure commercial products.
Consequently, many commercial secure phones augment a DH exchange with a voice authentication digest ("VAD"), combined with a hash commitment at the start of the key exchange, to shorten the length of VAD material that must be read aloud. A VAD (also known as a short authentication string) consists of a short string or value that two users can exchange verbally to authenticate their connection and help protect against MitM attacks. Hash commitment refers to the use of an agreed-upon cryptographic hash to shorten the VAD material. No PKI is required for this approach to authenticating the DH exchange. The AT&T 3600, Eric Blossom's COMSEC secure phones, PGPfone from PGP Corporation, and Cryptophone from GSMK mbH are all examples of products that utilize this simpler lightweight approach.
Certain problems exist with the VAD and hash commitment approach, however, including inattentive users who may not execute the voice authentication procedure or unattended secure phone calls to answering machines that cannot execute the voice authentication procedure. Additionally, a VAD must be employed for each call between users.
What is needed, then, is a method for allowing a user to easily establish multiple trusted VOIP communication sessions with other previously-authenticated users without the need to perform a voice authentication for each VOIP communication session. Such a method should not rely on intermediaries or complex infrastructure technology and should easily allow authentication of future calls.

Method and system for key management in voice over internet protocol


A heat pump system (10) includes a compressor (20), a reversing valve (30), an outdoor heat exchanger (40) and an indoor heat exchanger (50) coupled via refrigerant lines (35, 45, 55) in a conventional refrigeration circuit, a refrigerant to liquid heat exchanger (60), a refrigerant to liquid heat exchanger bypass valve (130), an outdoor heat exchanger bypass valve (230), and an indoor heat exchanger bypass valve (330). A controller (100) is provided to selectively control the respective positioning of the valves (30, 130, 230 and 330) between their respective open and closed positions so as to selectively configure the refrigerant circuit for operation in one of an air cooling only mode, an air cooling with liquid heating mode, an air heating only mode, an air heating with liquid heating mode, and a liquid heating only mode.

Reversible heat pumps are well known in the art and commonly used for cooling and heating a climate controlled comfort zone with a residence or a building. A conventional heat pump includes a compressor, a suction accumulator, a reversing valve, an outdoor heat exchanger with an associated fan, an indoor heat exchanger with an associated fan, an expansion valve operatively associated with the outdoor heat exchanger and a second expansion valve operatively associated with the indoor heat exchanger. The aforementioned components are typically arranged in a closed refrigerant circuit pump system employing the well known refrigerant vapor compression cycle. When operating in the cooling mode, excess heat absorbed by the refrigerant in passing through the indoor heat exchanger is rejected to the environment as the refrigerant passes through the outdoor heat exchanger.
It is well known in the art that an additional refrigerant-to-water heat exchanger may be added to a heat pump system to absorb this excess heat for the purpose of heating water, rather than simply rejecting the excess heat to the environment. Further, heat pumps often have non-utilized heating capacity when operating in the heating mode for heating the climate controlled zone. For example, each of U.S. Pat. Nos. 3,188,829; 4,098,092; 4,492,092 and 5,184,472 discloses a heat pump system including an auxiliary hot water heat exchanger. However, these systems do not include any device for controlling the refrigerant charge within the refrigerant circuit. Therefore, while functional, these systems would not be optimally efficient in all modes of operation.
In heat pump systems, the outdoor heat exchanger and the indoor heat exchanger each operate as evaporator, condenser or subcooler, depending on the mode and point of operation. As such, condensing may occur in either heat exchangers, and the suction line may be filled with refrigerant in a gaseous or liquid state. As a consequence, the amount of system refrigerant charge required in each mode of operation in order to ensure operation within an acceptable efficiency envelope will be different for each mode.
U.S. Pat. No. 4,528,822 discloses a heat pump system including an additional refrigerant-to-liquid heat exchanger for heating liquid utilizing the heat that would otherwise be rejected to the environment. The system is operable in four independent modes of operation: space heating, space cooling, liquid heating and simultaneous space cooling with liquid heating. In the liquid heating only mode, the indoor heat exchanger fan is turned off, while in the space cooling and liquid heating mode, the outdoor heat exchanger fan is turned off. A refrigerant charge reservoir is provided into which liquid refrigerant drains by gravity from the refrigerant to liquid heat exchanger during the liquid heating only mode and the simultaneous space cooling and liquid heating mode. However, no control procedure is disclosed for actively controlling refrigerant charge in the refrigerant circuit in all modes of operation. Further, no simultaneous space heating and liquid heating mode is disclosed.
Accordingly, it is desirable that heat pump system with liquid heating capability operate effectively in an air cooling only mode, an air cooling and liquid heating mode, an air heating only mode, an air heating and liquid heating mode, and a liquid heating only mode.

Heat pump system having auxiliary water heating and heat exchanger bypass


A mechanism for folding a bicycle according to the invention comprises an upper grip, a lower grip, an upper tube base, a lower tube base and an adjustable set pin. By the connecting pin, the upper grip is able to turn around on the lower grip, and a handle, a pulling eye and a hook are provided with the upper grip. When folding, let the contact rim of the adjustable set pin in contact with the depressed surface, then pull the upper grip upwards with a finger inserting into the pulling eye and against the resistive force of the spring, bring the hook to engage it with the hanger provide on the upper tube base latching closely together the upper and lower tube bases. In case of unfolding, insert a finger into the pulling eye and pull it upwards and outwards simultaneously and forcefully. The mechanism according to the invention assures easy and prompt for folding or unfolding the frame of a bicycle with simple and secure construction.

1. Field of the Invention
The present invention relates to a mechanism for folding a bicycle which is simple in construction yet easy for folding and unfolding without using any tools.
2. Description of the Prior Art
At present, a bicycle with foldable frame becomes very popular and welcomes by the users. However, tightening with screw is generally employed as a method for folding its frame causing the necessity of using tools for folding and taking apart that is inconvenient to the users. In addition, the construction of the conventional bicycle folder is rather complicated, and its production cost is high even though it does not have any means for assuring security.

Room No. A, 3F., No. 112, Sec. 2, Chung Shan N. Rd.


An improved float assembly for crab traps includes a polyurethane float with a chemical with-standing surface formed around a first abrasion-resistant float tube and second abrasion-resistant float tube each having a flanged end and a non-flanged end. A collar having an inside diameter necessary for press fit or interference fit on an outside diameter of the float tubes for securing the non-flanged ends of the float tubes together. The collar permits the float tubes to be used in a variety of float sizes. A second embodiment utilizes telescoping float tubes such that the float tubes are secured together without the use of a collar. In preferred embodiments, the flanged ends extend outward perpendicularly to longitudinal axes of the float tubes or extend outward in a generally spheroidally arched manner. The flanged ends provide support to critical areas of the float especially susceptible to wear and tear. A crab trap rope extends through the float tubes and a stop surrounding the rope is secured to the rope and inserted into the top of one of the float tubes for securing the float on the rope for preventing damage to the float by the rope. The polyurethane float is capable of being painted and cleaned and has the advantage of preventing deterioration of the float caused by harsh marine environments.

The present invention relates to an improved crab trap float and a method for making the same.
Crab trap floats are traditionally composed of polystyrene. Due to long and continual exposure to the harsh marine environment polystyrene floats are susceptible to degradation. As a result of such degradation, floats are often weakened to the point where they break apart from a crab trap rope. This results in the loss of the attached trap. Furthermore, degradation can occur when a float is exposed to gasoline or solvent while the trap is being serviced. Exposure to gasoline or solvents causes the polystyrene float to quickly deteriorate and shrivel and dissolve.
Another disadvantage of polystyrene is that it cannot be painted with conventional paints because the solvents in the paints cause the polystyrene to deteriorate. Consequently, virtually all traps are white often making it difficult for an owner to visually spot his traps from a distance.


The present invention relates to an arrangement for increasing a relative change in resistance of a magnetoresistive memory cell (17) having in each case a memory layer (1) and a reference layer (3) on both sides of a tunnel barrier (2), the reference layer (3) being fashioned as a magnetically soft layer, and the magnetization thereof, which can be influenced by write operations, being oriented correctly again by a reference backup field or a reference magnetization current (11).

1. Field
The following relates to an arrangement for increasing a relative difference in resistance of a magnetoresistive memory cell having in each case a memory layer and a reference layer on both sides of a tunnel barrier between a first magnetization state and a second state.
2. Background Information
A magnetoresistive memory cell usually comprises two ferromagnetic systems with a non-ferromagnetic isolating layer situated in between. In the simplest case, the two systems comprise a ferromagnetic layer in each case.
The first ferromagnetic layer is typically made of a hard-magnetic material, for instance a cobalt-iron alloy. This ferromagnetic layer, with a constant magnetization in terms of magnitude and direction, functions as a reference layer.
The second ferromagnetic layer made of a soft-magnetic material, typically a nickel-iron alloy, forms a memory layer. In a manner corresponding to a data content of the memory cell, the magnetization of the memory layer is oriented unidirectionally or oppositely directed with respect to the magnetization of the reference layer. The memory cell thus has two distinguishable magnetization states (unidirectional, oppositely directed) in accordance with its data content.
If the magnetoresistive memory cell is based on the tunnel effect, then the material of the isolating layer is a dielectric. The frequency of a transition of electrons from one ferromagnetic layer to the other is higher in the case of unidirectional magnetization of the two ferromagnetic layers than in the case of oppositely directed magnetization of the two layers. From the conductivity of the layer system, it is possible to deduce the orientation of the magnetization of the memory layer relative to the magnetization of the reference layer and thus the data content of the memory cell.
The more pronounced the difference in conductivity or electrical resistance for the two magnetization states of the magnetoresistive memory cell, the higher the degree of interference immunity with which, and more simply, the data content of the memory cell can be read out. The difference in resistance behavior becomes greater, the fewer magnetic domain regions the two ferromagnetic layers have and the higher the spin polarization within the two layers.
In the known art, the difference in resistance for the two magnetization states is 15-20%, for example, in the case of magnetoresistive memory cells based on the tunnel effect. In a semiconductor device having magnetoresistive memory cells, by contrast, the resistance of two adjacent memory cells in the semiconductor device with the same magnetization state can also be significantly more than 20%. The conductivity thus diverges between two memory cells of equal magnetization with the same order of magnitude as between the two magnetization states of a memory cell. This makes it considerably more difficult to evaluate the magnetization state and assess the data content of a memory cell.
In conventional concepts for the reference layer of a magnetoresistive memory cell, the reference layer is designed as a magnetically hard layer which receives its magnetization in the course of a fabrication process for a semiconductor device having a magnetoresistive memory cell and essentially retains it for an entire service life of the semiconductor device. Temperature and long-term data stability of the magnetoresistive memory cell depend directly on the stability of the magnetization of the reference layer.
In present concepts, the reference layer is either coupled (pinned) to natural antiferromagnetic layers or supplemented with at least one further ferromagnetic layer of oppositely directed magnetization to form an artificial antiferromagnet. Ferromagnetic and antiferromagnetic systems that are coupled to such an extent via the Rudermann-Kittel-Kasuya-Yoshida (RKKY) interaction have an improved temperature and long-term data stability compared with individual hard-magnetic layers and are less sensitive to interfering magnetic fields.
FIG. 3 illustrates a diagrammatic cross section through a magnetoresistive memory cell. A reference system 6 and a memory system, which in this case comprises an individual memory layer 1, lie opposite one another on both sides of a tunnel barrier 2. The reference layer 3 is a sublayer of the reference system 6 which is oriented towards the tunnel barrier 2. In this case, the reference system 6 is fashioned as an artificial antiferromagnetic layer system (AAF), comprising the reference layer 3 and a reference coupling layer 5 on both sides of a spacer layer (a spacer) 4, a magnetization 9 of the reference coupling layer 5 being oppositely directed with respect to a reference magnetization 8 of the reference layer 3.
In a similar manner, the reference layer 3 (then as pinned layer) can be coupled via the spacer 4 to another layer (pinning layer) made of a naturally antiferromagnetic material. Such concepts are known from magnetic sensors and, in particular, from magnetic read/write heads.
A plurality of coupling mechanisms, for instance Néel interaction (orange peel coupling), pinhole coupling and interactions via magnetic leakage fields, act between the reference layer 8 or the reference system 6 and the memory layer 7.
Layers that are strongly coupled to one another react more sluggishly with respect to a magnetization reversal than weakly coupled systems. Therefore, present-day concepts for reference systems attempt to reduce the magnitudes of these interactions in order to obtain better dynamic properties of the magnetoresistive memory cell.
Secondly, a bias field resulting from the sum of the interactions, in the memory layer of the magnetoresistive memory cell, leads to an asymmetrical switching behaviour of the memory layer. Therefore, the present concepts attempt to achieve compensation of the magnetic coupling mechanisms at the location of the memory layer.
To summarize, the following, partly conflicting requirements result for the reference layer, or a reference layer system: (i) temperature stability, long-term data stability and magnetic field insensitivity each require a thick and magnetically hard reference layer; (ii) a low magnitude of the Néel coupling requires a thick memory layer; and (iii) a symmetrical switching behavior of the memory layer presupposes a reliably reproducible surface roughness of the reference layer and an adjustable leakage field.

Magnetoresistive memory cell with dynamic reference layer


Various embodiments include systems for controlling the flow of main steam from a high-pressure (HP) turbine to a turbine packing. In some cases, a system is disclosed including: a high pressure (HP) turbine including a plurality of stages, the plurality of stages including an early stage, a middle stage and a later stage; an intermediate pressure (IP) turbine operably connected with the HP turbine; a packing separating the HP turbine and the IP turbine; a main conduit fluidly connecting the middle stage of the HP turbine and the packing, the main conduit including a main valve; and a bypass conduit fluidly connected to the main conduit and bypassing the main valve, the bypass conduit including: a blocking valve; and an opening between the blocking valve and a downstream connection with the main conduit.

During operation of a turbine system employing a joint high-pressure (HP) and intermediate-pressure (IP) turbine, steam is conventionally extracted at a desired temperature from middle stages of the HP turbine section, where that steam is piped into a packing separating the HP turbine section and the IP turbine section. This extracted steam can be used to cool the packing (also known as an N2 packing) separating the HP turbine section and the IP turbine section. Conventionally, the flow of this extracted steam is controlled by one or more valves, which can be subject to fluctuations in flow that cause wear on the valves and undesirable noise.


Octafluoropropane is produced by a process including a step (1) of reacting hexafluoropropene with hydrogen fluoride in a gas phase at a temperature of from 150 to 450° C. in the presence of a fluorination catalyst to obtain 2H-heptafluoropropane and a step (2) of reacting 2H-heptafluoropropane obtained in step (1) with fluorine gas in a gas phase at a temperature of from 250 to 500° C. in the absence of a catalyst to obtain octafluoropropane. High-purity octafluoropropane is obtained which can be used in a process for producing a semiconductor device.

Octafluoropropane is used, for example, as a dry-etching or cleaning gas in the process for producing a semiconductor device. With respect to the production methods thereof, the following methods are known:
(1) a method of performing a direct fluorination reaction between hexafluoropropene and fluorine gas (see, Japanese Examined Patent Publication No. 62-61572 (JP-B-62-61572)),
(2) a method of performing an electrolytic fluorination of hexafluoropropene in hydrogen fluoride (see, Japanese Examined Patent Publication No. 62-61115 (JP-B-62-61115)),
(3) a method of reacting hexafluoropropene with fluorine in the presence of a catalyst (see, Japanese Examined Patent Publication No. 1-45455 (JP-B-1-45455)), and
(4) a method of reacting hexafluoropropene with a high-order metal fluoride (see, Japanese Examined Patent Publication No. 62-54777 (JP-B-62-54777)).
However, in these methods, by-products such as tetrafluoromethane (CF4) and hexafluoroethane (C2F6) are produced due to cleavage, C6F12 and C6F14 are produced due to radical addition, and a 4-membered ring is produced due to cyclization addition, for example, and as a result, the yield of and selectivity for the objective octafluoropropane decrease. Furthermore, some compounds in these impurities are difficult to separate by distillation and, in turn, high-purity octafluoropropane can hardly be obtained. Particularly, in the case of using hexafluoropropene as the starting material, chloropentafluoroethane (CFC-115) contained as an impurity scarcely reacts with fluorine gas and mostly remains in the objective octafluoropropane and since this impurity compound can hardly be separated by distillation, due to the similar boiling points, production of high-purity octafluoropropane is difficult.


The present disclosure relates to a stretchable fiber optic sensor that can measure tension, bending, and torsion direction of an object. The fiber optic sensor includes an optical fiber with a fiber Bragg grating (FBG) embedded in a sinusoidal configuration at an off-center position of a deformable substrate.

Stretchable, skin-mountable, and wearable devices with monitoring capabilities have attracted tremendous attentions in recent years, due to the wide range of applications in health indicator monitoring, body movement detection, and soft robotics. All these applications require the sensors to be flexible and stretchable such that it can fit to the movement of the flexible object for sensing. Soft electronics and liquid metals are two commonly used techniques for designing stretchable sensors which are capable of measuring strain, force, pressure, and temperature. Most existing approaches are based on the change in resistivity, conductivity, capacitive, and inductivity of the sensor, which is not suitable for magnetic resonance imaging (MRI) or harsh environments.

UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC


Patients suffering vascular injury as a result of balloon catheterization or the like are treated with medicaments containing conjugates comprising a ligand, such as bFGF (or another FGF polypeptide), and a cytotoxic agent. The cytotoxic agent can be a ribosome-inactivating protein (RIP), such as saporin, which is attached to the ligand through a chemical bond or prepared as a recombinant DNA chimera. The medicament containing the conjugate is administered IV to patients after they have been treated for atherosclerosis in a manner which commonly results in vascular injury, particularly to the intima, and effectively prevents restenosis. The conjugate kills proliferating smooth muscle cells in the lumen of the blood vessels which surprisingly express large numbers of high-affinity bFGF receptors while not inhibiting the growth of endothelial cells.

Despite declining fatality rates, atherosclerosis remains the leading killer in industrialized nations. Many attempts have been made to prevent or to reverse atherosclerosis, and also to prevent rapid smooth muscle and other proliferation which may contribute importantly to pulmonary hypertension, transplant rejection, and restenosis after angioplasty or bypass grafting. Such attempts have included the use of antihypertensive and cholesterol-lowering agents, fish oils, corticosteroids, cyclosporin A, heparin and non-anticoagulant heparin fragments, inhibitors of angiotensin-converting enzyme, calcium antagonists, aspirin, prostacyclin and other modulators of platelet and smooth muscle eicosanoid metabolism, colchicine, terbinafine, triazolopyrimidine, analogues of somatostatin, anti-neoplastic agents, seeding with endothelial cells, and devices intended to produce less vascular trauma than balloon angioplasty, such as laser angioplasty and atherectomy. Although preliminary results in experimental animals and in humans show promise for some of these therapies, most will require sustained or local application.
Basic fibroblast growth factor (bFGF) is a protein which has a molecular weight of approximately 16 kD, is acid- and temperature-sensitive and has a high isoelectric point. A structurally related protein, acidic FGF (aFGF), has an acidic isoelectric point. FGFs exhibit a mitogenic effect on a wide variety of mesenchymal, endocrine and neural cells. Of particular interest is their stimulatory effect on collateral vascularization and angiogenesis. Such mitogenic effects have stimulated considerable interest in FGFs as potential therapeutic agents for wound healing, nerve regeneration and cartilage repair, for example.
New capillary growth takes place by a series of sequential steps beginning with the dissolution of the capillary basement membrane. Microvascular endothelial cells stimulated by angiogenic substances, such as BFGF, in vitro secrete collagenase, plasminogen activator, and stromelysin which degrade the basement membrane and allow endothelial cells to migrate toward the angiogenic stimulus. After migrating, the endothelial cells proliferate, develop sprouts, form capillary-like hollow tubules, and finally link tubules into capillary loops.
Many cells that respond to basic FGF have been shown to possess specific receptors on the cell surface membranes. The receptor proteins appear to be single chain polypeptides with molecular weights ranging from 110 to 150 kD, depending on cell type. These receptor proteins bind basic FGF with high affinity (Kd=10-80 pill), and receptor numbers often range from 2000 to 80,000 per cell. Such receptors have been purified from chicken embryo and from rat brain, using a combination of lectin and ligand affinity chromatography and are associated with tyrosine kinase activity, see Imamura et al., B.B.R.C., 583-590 (1989); Huang and Huang, J. Biol. Chem., 261, 9568-9571 (1986).
On baby hamster kidney cells (BHK), two basic FGF receptors with estimated molecular weights of 110 and 130 kD have been reported in Neufeld et al., J. Biol. Chem., 260, 13860-13868 (1985) and Neufeld et al., J. Biol. Chem., 261, 5631-5637 (1986). Although both receptor proteins bind basic FGF and acidic FGF, it appears that the larger receptor protein binds bFGF preferentially and is sometimes referred to as the "high affinity" BFGF receptor; the smaller receptor has somewhat greater affinity for acidic FGF.
The feasibility of using receptor-specific ligands to transport toxins into cells has recently been demonstrated. The strategy, originally applied in immunotherapy by conjugating toxins to monoclonal antibodies (see Blakey et al., Cancer Research, 48, 7072-7078 (1988)), has recently been pursued by coupling toxins with classic endocrine hormones, such as CRF and TRF, with cytokines such as EGF and TGF.alpha. and with lymphokines such as interleukin-2. U.S. Pat. No. 4,468,382 to Bacha et al. shows cytotoxic conjugates wherein the hormone TRH is covalently linked to the toxin CRM 45 by bifunctional cross-linking agents to produce a toxic hybrid protein alleged to be useful in the treatment of certain tumors.
Atherosclerosis, sometimes referred to as arteriosclerosis, results from the development of an intimal lesion and the subsequent narrowing of the vessel lumen. Commonly, atherosclerosis originally appears as a result of the buildup of plaque which lines the interior of blood vessels, particularly the arteries. Whereas bypass surgery is sometimes employed to replace such clogged arteries, in recent years, a number of surgical procedures have been developed so as to interarterially remove such plaque, often by balloon catheterization or other such treatments in which the plaque is either compressed against or scraped away from the interior surface of the artery. Not infrequently, the patient so treated finds a recurrence of such narrowing of the vessel lumen in a relatively short period thereafter, generally referred to as restenosis, requiring a repetition of the surgical procedure to again remove the increasing blockage. A real need exists for preventing such recurrence in patients who have been treated for atherosclerosis.

The Salk Institute for Biological Studies


A motor vehicle collision warning system 1 comprises an obstacle sensing system 3 including a plurality of sensors 5 together capable of sensing obstacles around the vehicle 7 and generating obstacle of concern signals when obstacles are sensed, and a warning control system 9 for receiving the obstacle of concern signals and for determining whether a collision warning signal should be generated. The sensing system includes at least one antenna cluster 11 mounted in the region of a corner 13 of the vehicle 7, the antenna cluster 11 comprising a radar transmit antenna 15 and two receive antennas 17 and 19. The transmit antenna 15 is mounted between the receive antennas 17 and 19. Receive antenna 17 faces towards the front of the vehicle and receive antenna 19 faces towards the rear of the vehicle. A trigger means 21 triggers the operation of the transmit antenna 15 and one or both of the receive antennas 17 and 19.

This invention relates to collision warning systems for motor vehicles and in particular to an antenna cluster for use in such a collision warning system.
Various different types of collision warning systems have been proposed for motor vehicles which will warn of potential collision with moving targets, primarily other vehicles and stationary obstacles especially when parking. Such systems include "closing vehicle same lane warning systems" for looking behind a vehicle when it is traveling forwards for noting when a vehicle is approaching from the rear; parking aids for looking forwards when the vehicle is traveling slowly forwards and backwards when the vehicle is traveling slowly backwards; backup aids; short range frontal collision warning systems for looking ahead of the vehicle while driving forwards; parking space measuring aids for measuring the length of a parallel parking space to the side of the vehicle; driver induced impaired visibility aids to help ensure that the driver can notice vehicles approaching his side in an overtaking lane; side vision aids for looking to the side of the vehicle; and lane change aids for checking that the driver is free to overtake, or indeed move to an inside lane.
Typically these have all been designed as discrete packages and so a vehicle having a multiplicity of these aids includes a plurality of sensors of different types and ranges looking around the vehicle.
There are many different types of sensors available including radar and ultrasound sensors which are chosen depending upon the range required for the sensor. The majority of sensor types transmit a signal which is reflected from an obstacle and then received. Measurement of the time delay between transmission and receipt of the signal allows the position of the obstacle to be calculated.
The common features of the above collision warning systems are that they include a sensing system, which has at least one sensor with a field of view in which it may detect an obstacle, and a warning control system which receives "obstacle of concern" signals from the sensor and analyzes them to determine whether a collision warning signal should be generated. However, for each application and at any one time only obstacles in a particular area, known as the zone of concern, are of particular interest. For example, in the parking aid system, as the vehicle moves forward the area to the front and sides of the vehicle is the zone of concern. During reversing, the rear of the vehicle is of primary concern.
A collision warning system for a motor vehicle which is capable of acting as a multifunctional system is described in the applicants previous PCT application PCT/GB97/01728 in which each of the plurality of sensors has a predetermined field of view in which it is capable of detecting obstacles and an instantaneous field of view within which obstacles sensed by the sensor causes the obstacle sensing system to generate an obstacle signal. A vehicle operation sensing means detects at least one property of the vehicle's operation. A zone of concern control means defines a zone of concern within which sensed obstacles trigger the generation of an obstacle of concern signal whereby the zone of concern is defined in dependence on the property or properties of the vehicle's operation sensed by the vehicle operation sensing means. The zone of concern control means controls the sensors such that the instantaneous field of view of the sensors together cover the zone of concern.
The foregoing system includes four sensors which each comprise a transmitter antenna and a receiver antenna. The present invention relates to an antenna cluster especially suitable for use in such a system.

Antenna cluster for a motor road vehicle collision warning system


There are disclosed a process for producing a vinyl ester polymer having a high degree of polymerization at a high efficiency, which process comprises subjecting a vinyl ester monomer to seed polymerization by the use of a vinyl ester polymer emulsion as a seed emulsion under the conditions in which the charge of a water-soluble initiator per unit volume (1 liter) of reactant liquid charge is 1.times.10.sup.-8 to 2.times.10.sup.-4 mol, and the charge of the water-soluble initiator per one particle of the vinyl ester polymer particles in the seed emulsion is 1.times.10.sup.-28 to 1.times.10.sup.-20 mol, and a process for producing a vinyl alcohol polymer at a high efficiency from the vinyl ester polymer thus obtained.. According to these processes of the present invention, both a vinyl ester polymer and vinyl alcohol polymer each having a higher degree of polymerization can be produced with ease on an industrial scale.

1. Field of the Invention
The present invention relates to a process for producing vinyl ester polymer and a process for producing vinyl alcohol polymer. More particularly, it pertains to a process for producing vinyl ester polymer having a high degree of polymerization by means of seed polymerization or emulsion polymerization, a process for producing vinyl alcohol polymer having a high degree of polymerization by the use of said vinyl ester polymer obtained by the above-mentioned process, and a process for producing vinyl ester polymer emulsion well suited for use as a seed emulsion.
2. Description of the Related Arts
Vinyl ester polymer, especially vinyl acetate polymer is widely utilized as a base polymer of adhesives and paints, and is also of great importance as a raw resin of vinyl alcohol polymer. It is also well-known that vinyl alcohol polymer is not only utilized as a paper processing agent, textile processing agent, emulsion stabilizer, etc. but also assumes an important place as a raw material of vinylon film and vinylon fiber by virtue of its surpassing interfacial characteristics and strength properties as one of the crystalline water-soluble polymers limited in number.
Conventional vinyl alcohol polymer, however, is limited in the degree of polymerization, with an upper limit of 2000, and 3000 approximately in the case of a special product by reason of the fact that vinyl alcohol polymer having a high degree of polymerization is poor in processability and hard to handle and that vinyl acetate polymer as a raw material having a high degree of polymerization is difficult to obtain.
The recent rapid innovation in processing technique, however, has made possible the processing of polymers having a ultrahigh degree of polymerization thereby leading to success in deriving unique physical properties which have never been known. This is also the case with vinyl alcohol polymer, and that given a high degree of polymerization is expected to exhibit improved characteristic properties in the conventional application areas and also to find new uses in novel fields such as high tenacity fibers, polarizing film, etc.
As a general rule, a polymer having a high degree of polymerization is obtained by polymerization at a low temperature and at a low polymerization rate. This holds true for vinyl acetate, and several cases have been reported, (For example, A. R. Shultz; J. Am. Chem. Soc. 76, 3422(1954), G. M. Burnett, M. H. George, H. W. Melville; J. Polym. Sci. 16, 31(1955), and M. Matsumoto, Y. Ohyanagi; J. Polym. Sci, 26, 148(1960)).
However, the above-mentioned conventional processes are based on bulk polymerization, which involves several problems still unsolved such as difficulty in stirring due to high viscous polymerization system making the production of uniform polymer impossible, difficulty in removing the heat of polymerization, etc. Therefore, the industrial scale production by bulk polymerization is considered to be almost impossible.
In order to overcome the disadvantage of bulk polymerization, there is proposed a new process by suspension polymerization (Japanese Patent Application Laid-Open No. 148209/1986).
However, in a system with great chain transfer such as vinyl ester system, it is indispensable to lower the polymerization temperature for the purpose of increasing the degree of polymerization. Because of thus, the rate of polymerization is inevitably made quite low in bulk polymerization and suspension polymerization according to the reports hereinbefore.
There is also proposed another process, that is, low temperature emulsion polymerization as a process having overcome the disadvantages of the above polymerization processes, which process is different from bulk polymerization and suspension polymerization in polymerization mechanism, almost free from the problems of stirring and heat removal even at a relatively high rate of polymerization, and makes it possible to obtain vinyl ester polymer and vinyl alcohol polymer each having a high degree of polymerization (Japanese Patent Application Laid-Open No. 37106/1988).
Nevertheless, there still remain some problems in the aforementioned low temperature emulsion polymerization that a long time is required from the beginning of an initiator addition to the start of polymerization, the ratio of weight-average molecular weight of vinyl alcohol polymer having a high degree of polymerization obtained (Mw) to number-average molecular weight of the same (Mn) (Mw/Mn) is high, which means a wide range of molecular-weight distribution, and the vinyl alcohol polymer thus obtained has an average degree of polymerization of only 25,000 at the highest.
There is also known a polymerization process in which 0.01 to 0.6% by weight of an anionic emulsifier is added to vinyl chloride monomer, and prior to the completion of polymerization, at least 0.2% by weight of an nonionic emulsifier is added to the monomer to complete emulsion polymerization and produce an emulsion, which is then used as a seed emulsion for seed-polymerizing vinyl chloride monomer (Japanese Patent Application Laid-Open No. 60389/1979). The process, however, is directed to the process for producing a vinyl chloride polymer emulsion having a sharp particle size distribution and large particles and is incapable of producing a vinyl ester polymer having a high degree polymerization.
There is further known a polymerization process in which ethylene and vinyl acetate are subjected to continuous emulsion polymerization by using vinyl acetate polymer emulsion or ethylene-vinyl acetate copolymer emulsion each obtained by emulsion polymerization at 40.degree. to 75.degree. C. (Japanese Patent Application Laid-Open No. 145783/1979). However, the process fails to produce a vinyl ester polymer having a high degree of polymerization.
There is further known a polymerization process in which a monomer of vinyl acetate or acrylic acid is subjected to emulsion polymerization at 50.degree. to 90.degree. C. to produce an emulsion, which is then used as seed emulsion for seed-polymerizing ethylene, styrene, acrylic acid, etc. at 50.degree. to 90.degree. C. and at an initiator charge of 5.0.times.10.sup.-4 to 5.0.times.10.sup.-3 mol per unit volume (1 liter) of reactant liquid charge (Japanese Patent Application Laid-Open No. 103489/1979). The process, however, is incapable of producing a vinyl ester polymer having a high degree of polymerization because of a large amount of initiator charge required and a high polymerization temperature.

Process for producing vinyl ester polymer and process for producing vinyl alcohol polymer


The invention claimed is a novel magnetic mirror air bearing for a Michelson interferometer with lateral motion. A precise kinematic mount is used in combination with magnetic fields wherein current can be applied on a centerline to move a piston and mirror laterally without pitch and yaw so as to effect accurate light beam reflection regardless of distance of lateral movement within a defined space. The assembly is able to operate across extended temperature ranges by utilizing materials which expand and contract at similar rates, and contains a thermalizing cavity which will thermalize the gas to avoid temperature induced artifacts.

The invention most closely corresponds with USPTO Class 310, subclass 15 relating to electrical generator or motor structure wherein the invention involves subject matter in which the movable element of the dynamoelectric device moves to and fro along a straight line path or along an accurate path which is so short as to be substantially a straight line.
In its simplest form, the invention comprises a novel method and apparatus for moving a mirror laterally without angular distortion (pitch and yaw) so as to reflect a light beam in a desired and precise angle, and without temperature induced artifacts. In the present invention's realm, pitch and yaw refer to the attitude of a light beam reflected off a mirror in terms of a symmetrical beam wherein the directional stability in yaw is the same as the pitch stability.
In precision instruments, the accuracy of the instrument's performance is a crucial element. In re Binnard, et al., U.S. Pat. No. 7,368,838, a high efficiency voice coil motor is described wherein a manner of magnetic field application is used. Binnard, however, lacks many of the features contained in the present invention, and limits itself to specific types and shapes of magnets. Further, there is no elegant method of controlling the temperature of the Binnard assembly as exists in the present invention. These differences will be apparent to one skilled in the art as detailed within this Specification.

Magnetic mirror air bearing for Michelson interferometer with lateral motion


Real-time segmentation of foreground from background layers in binocular video sequences may be provided by a segmentation process which may be based on one or more factors including likelihoods for stereo-matching, color, and optionally contrast, which may be fused to infer foreground and/or background layers accurately and efficiently. In one example, the stereo image may be segmented into foreground, background, and/or occluded regions using stereo disparities. The stereo-match likelihood may be fused with a contrast sensitive color model that is initialized or learned from training data. Segmentation may then be solved by an optimization algorithm such as dynamic programming or graph cut. In a second example, the stereo-match likelihood may be marginalized over foreground and background hypotheses, and fused with a contrast-sensitive color model that is initialized or learned from training data. Segmentation may then be solved by an optimization algorithm such as a binary graph cut.

Separating a foreground layer from video in real time may be useful in many applications such as live background substitution, pan/tilt/zoom, object insertion and the like in teleconferencing. Separating a foreground layer in real time demands layer separation to near Computer Graphics quality, including ∝-channel determination as in video-matting, but with computational efficiency sufficient to attain live streaming speed.


A self-test system for a shorted diode protection circuit in an electric vehicle propulsion system includes a series of relays for selectively coupling a battery in circuit with a field winding of a generator, the shorted diode protection circuit being coupled in voltage sensing arrangement with the field winding. The relays are operated to induce current in forward and reverse directions through the winding in separate test stages. At each stage the winding is disconnected from the battery so that inductive reactance creates a voltage on the winding to actuate the protection circuit. A system controller records whether the protection circuit is responsive and therefore operable and alerts a vehicle operator.

This invention relates generally to electrical propulsion systems for diesel electric traction vehicles such as locomotives and, more particularly, to a self-test circuit for determining the operability of a shorted diode protection circuit in such a system.
In a conventional diesel electric traction vehicle such as a locomotive, a diesel engine is used to drive a synchronous generator that supplies electric current to a plurality of electric traction motors whose rotors are drivingly coupled to the respective wheel axle sets of a locomotive. The generator is typically a three-phase traction alternator having a rotor mechanically coupled to the output shaft of the diesel engine. When excitation current is supplied to field windings of the generator, alternating voltages are generated in the three-phase armature windings. These voltages are coupled to a full-wave bridge rectifier and converted to direct current power on a DC link. In a traction vehicle in which the electric motors are alternating current (AC) motors, the voltage on the DC link is applied to a plurality of inverters which convert the DC voltage to controlled frequency AC voltage for application to the motors.
An on-board control system controls operation of the diesel engine, synchronous generator and inverter in such a manner as to regulate the power applied to the traction motors so as to provide a desired amount of power at the wheels of the traction vehicles to attain a desired speed. In most systems, the diesel engine is operated at a constant speed and the power supplied by the synchronous generator is regulated by varying the field current. Variations in the field current at constant speed will control the magnitude of voltage produced at the armature windings. During normal running conditions, the current being generated by the synchronous generator may be several thousand amperes. If the rectifier circuit connected to the armature windings were to fail to a short circuit condition under such high currents, the amplitude of the armature current will tend to increase abruptly to a much higher peak than normal and then to decay with time. Such initial high current conditions may severely damage the generator and prevent operation of the traction vehicle. For that reason, such vehicles typically include a shorted diode protection circuit connected in circuit with the field winding of the generator for detecting the occurrence of a short circuit condition. The sudden high current condition in the armature windings will produce a magnetomotive force that almost directly opposes the generator field magnetomotive force thereby tending to de-magnetize or weaken the magnetic field in the stator rotor air gap of the generator. This de-magnetizing magnetomotive force induces extra current in a field winding so that the total flux linkages will remain constant. This extra current will create a reflected voltage on the field winding that can be detected by the shorted diode protection circuit. The shorted diode protection circuit immediately transmits a signal to the system controller to effect a rapid removal of excitation current to the field winding so as to cause the generator power to be rapidly reduced. The effect of the shorted diode protection circuit is to reduce the output current of the generator before the maximum available short circuit current is realized.
In known systems, there has been no convenient method for determining whether or not the shorted diode protection circuit in such a traction vehicle is actually operative, although the circuit can be checked out in a repair facility by either removing the protection circuit from the locomotive or by coupling external power sources to the protection circuit. Accordingly, it would be advantageous to provide a system which could routinely test the operability of the shorted diode protection circuit and advise a locomotive operator whether or not it is safe to operate the locomotive.

Self-test circuit for a shorted diode protection panel in a diesel electric locomotive


To survey a subterranean structure, first measurement data according to a first electromagnetic survey technique and second measurement data according to a second, different electromagnetic survey technique are received. An output value for surveying the subterranean structure is computed based on the first and second measurement data.

Various electromagnetic techniques exist to perform surveys of subterranean structures underneath a surface for identifying structures of interest. Examples of structures of interest in the subterranean structure include subsurface resistive bodies, such as oil-bearing reservoirs, gas injection zones, and fresh-water aquifers. One survey technique is the magnetotelluric (MT) survey technique that employs time measurements of electric and magnetic fields (which are responsive to naturally occurring electromagnetic fields) for determining the electrical conductivity distribution beneath the surface. Another survey technique is the controlled source electromagnetic (CSEM) survey technique, in which an electromagnetic transmitter is used to generate electromagnetic signals. With either survey technique, surveying units (or receivers) containing electric and magnetic field sensors are deployed on a surface within an area of interest to make measurements from which a geological survey of the subterranean structure underneath the surface can be derived.
A shortcoming of MT survey techniques is that they are relatively insensitive to thin resistive layers that are typically present in subterranean structures. A thin resistive layer can be a thin (in the vertical direction) reservoir of oil, gas, or fresh water.
Conventional CSEM survey techniques are limited by the so-called air-wave problem, which prevents effective use of the CSEM survey techniques in shallow water applications. In a subsea environment, the air-wave problem is caused by a component of the electromagnetic signal that is generated by the source (the CSEM electromagnetic transmitter), which component can be thought of as following a path upwards from the transmitter to the sea surface, horizontally through the air, and then back down through the sea water to receivers (usually located on a seabed). In deep water applications, the air-wave component does not present a major issue, since the air-wave component is attenuated significantly as the air-wave component passes through the sea water. However, in a shallow water application, the air-wave component is not attenuated as much, so that the air-wave component may dominate the signals that are received by the receiver located at the seabed. In such a scenario, the measurements made by receivers used in a CSEM survey technique would not produce very useful information for the purpose of determining whether a resistive body is located in the subterranean structure.
On land, the air-wave problem is caused by electromagnetic signals propagating from a CSEM electromagnetic transmitter laterally through the air along the air-land interface to receivers. These air-wave electromagnetic signals propagating parallel to the land surface are insensitive to subsurface structures; therefore, such air-wave electromagnetic signals (which are received by the receivers) may interfere with proper detection of resistive objects in a subterranean structure.

Computing values for surveying a subterranean structure based on measurements according to different electromagnetic survey techniques


Embodiments relate to the orchestration of data shuffling among memory devices of a non-uniform memory access device. An aspect includes a method of orchestrated shuffling of data in a non-uniform memory access device includes running an application on a plurality of threads executing on a plurality of processing nodes and identifying data to be shuffled among the plurality of processing nodes. The method includes registering the data to be shuffled and generating a plan for orchestrating the shuffling of the data. The method further includes disabling cache coherency of cache memory associated with the processing nodes and shuffling the data among all of the memory devices upon disabling the cache coherency, the shuffling performed based on the plan for orchestrating the shuffling. The method further includes restoring the cache coherency of the cache memory based on completing the shuffling of the data among all of the memory devices.

The present disclosure relates generally to memory access devices and, more specifically, to data shuffling in non-uniform memory access devices.
Non-uniform memory access (NUMA) architectures have begun to emerge as architectures for improving processor performance, such as in multi-core processors. In a NUMA architecture, each socket or processing node has its own local memory, such as dynamic random access memory (DRAM), and each socket or processing node is connected to the other sockets to allow each socket to access the memory of each other socket. Thus, in NUMA architectures, access latency and bandwidth vary depending on whether a socket is accessing its own local memory or remote memory of another socket or processing node.
At some point in the execution of an application, threads executing on the processing nodes have to exchange intermediate results, including one or both of instructions and non-instruction data, with threads executing on other processing nodes. To exchange the results, the data is copied to the local memory associated with the destination thread. The copying is performed during a shuffle operation in which each thread exchanges data with some other thread. The shuffling is a global barrier for all participating threads. The shuffling starts after all threads have reached the barrier, and the threads resume processing only after shuffling among all of the threads is complete.

Data shuffling in a non-uniform memory access device

International Business Machines Corporation


A method of fabricating a silicon-germanium CMOS includes preparing a silicon substrate wafer; depositing an insulating layer on the silicon substrate wafer; patterning and etching the insulating layer; depositing a layer of polycrystalline germanium on the insulating layer and on at least a portion of the silicon substrate wafer; patterning and etching the polycrystalline germanium; encapsulating the polycrystalline germanium with an insulating material; rapidly thermally annealing the wafer at a temperature sufficient to melt the polycrystalline germanium; cooling the wafer to promote liquid phase epitaxy of the polycrystalline germanium, thereby forming a single crystal germanium layer; and completing the CMOS device.

Prior art high-speed integrated circuits are formed by shrinking the device size to shorten the carrier transit time, and using strained silicon to increase carrier mobility. Both processes require short-channel devices and complicated fabrication processes.
The electron and hole mobility of germanium is about three times higher than that of silicon, therefore, the speed of a germanium CMOS is expected to be at least two times greater than that of the same generation of silicon CMOS integrated circuit. For germanium-on-insulator (GOI) technology, the speed is expected to increase at least two times that of silicon-on-insulator (SOI). Very high performance system-on-chip (SOC) integrated circuits may be fabricated using GOI CMOS for the high speed portion of the SOC and SOI CMOS for the lower speed portion of the integrated circuit. SOC chip performance may be substantially greater than a state-of-the art silicon integrated SOC using the same generation of integrated circuit fabrication process.
Liu et al., High quality single-crystal Ge on insulator by liquid-phase epitaxy on Si substrate, Applied Physics Letters, vol. 84, no. 14, pp 2563-2565, describes fabrication of a germanium-on-insulator device wherein germanium crystal orientation is controlled by forming a seed layer on the silicon substrate.

Method of growing a germanium epitaxial film on insulator for use in fabrication of CMOS integrated circuit


A method and apparatus of requesting a channel access in a wireless local area network is provided. A transmitter transmits a plurality of Request To Send (RTS) frames over a plurality of requesting channels and receives at least one Clear To Send (CTS) frame over at least one responding channel as a response for the plurality of RTS frames. Each of the plurality of RTS frames indicates a bandwidth for the plurality of requesting channels, and the at least one CTS frame indicates a bandwidth for the at least one responding channel.

1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for requesting a channel access in a wireless local area network.
2. Related Art
With recent development of information and communications technology, various wireless communications technology has been developed. Among them, a wireless local area network (WLAN) is technology that allows portable user equipment such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), etc. in a home, an enterprise or a certain service providing zone to have wireless access to high-speed Internet on the basis of radio frequency technology.
It is presupposed that communications in the WLAN based on institute of electrical and electronics engineers (IEEE) 802.11 standards are performed within a zone called a basic service set (BSS). The BSS zone has a somewhat indefinite boundary since it may vary depending on propagating characteristics of a wireless medium. Such a BSS is basically divided into two configurations of an independent BSS (IBSS) and an infrastructure BSS. The former indicates a BSS that forms a self-contained network and does not allows access to a distribution system (DS), and the latter indicates a BSS that includes one or more access points (AP), a distribution system, etc. and generally employs the AP in all communications including communication between stations.
The station (STA) having desire to access a wireless network may use two scanning methods for searching an accessible wireless network (BSS or IBSS), i.e., a candidate AP or the like.
One is passive scanning, which uses a beacon frame transmitted from the AP (or STA). That is, the STA having desire to access a wireless network periodically receives the beacon frames from the AP or the like managing a relevant BSS (or IBSS), thereby finding the accessible BSS or IBSS.
The other is active scanning. The STA having desire to access the wireless network first transmits a probe request frame. Then, the STA or AP that receives the probe request frame responds with a probe response frame.
TV Whitespace includes channels allocated to broadcast TV, which are permitted to be used by cognitive radio device. TV White Space may include UHF band and VHF band. The spectrum (hereinafter, can be called as 'White Space') not used by a licensed device can be used by an unlicensed device. The frequency band permitted to be used by unlicensed device can be differently defined for each country. Generally, this frequency band comprises 54-698 MHz (US, Korea), and some of this frequency band can't be used for the unlicensed device. Here, 'licensed device ' means a device of the user permitted in this frequency band, and can be differently called as 'primary user', or 'incumbent user'. The unlicensed device, which wishes to use the TV White Space (TVWS), shall acquire information for available channel list at its location.
An unlicensed device should provide a protection mechanism for the incumbent user. That is, the unlicensed device should stop using a specific channel, when an incumbent user, such as wireless microphone, is using that specific channel. For this purpose, spectrum sensing mechanism is required. Spectrum sensing mechanism comprises Energy Detection scheme, Feature Detection scheme, etc. By using this mechanism, unlicensed device determines that the channel is used by an incumbent user, when the strength of the primary signal is greater than a predetermined level, or when Digital Television (DTV) Preamble is detected. And, the unlicensed device (station or access point) shall lower its transmit power, when it is detected that the neighboring channel, next to the channel used by the unlicensed device, is used by the incumbent user.
On the other hand, in order to efficiently operate the unlicensed device on TVWS, more discussion is needed on an enabling mechanism of letting the unlicensed device to operate in TVWS, how efficiently the unlicensed device finds the network to be connected, how the information for the available channel in TVWS is efficiently acquired, efficient format of that information, and efficient signaling mechanism to exchange this information, etc.

Method and apparatus of requesting channel access in wireless local area network


A system for subdividing a building space into work areas includes interconnectable partition panels, each having an internal frame with a plurality of horizontal frame members located at predetermined heights. The horizontal frame members each have at least one horizontal row of slots, and at least one of the horizontal frame members is located slightly above an optimal worksurface height for supporting an interactively used datum shelf. Furniture components are attachable to the horizontal frame members at selected horizontal positions, including the datum shelf, an undershelf storage unit, and an upper storage unit. A mobile furniture unit is provided having a worksurface located at an optimal worksurface height, the worksurface having a cantilevered edge section that can be extended partially under the datum shelf at a selected optimal depth for coordinated and efficient use of the datum shelf concurrent with using the worksurface. The furniture unit is constructed to maximize floor space and storage within an office area or work area while maintaining a minimum footprint. Further, the furniture unit allows user reconfiguration and provides for maximum work efficiency and adaptability. Also, the work area defined by the instant construction is noticeably open and spacious, even where the actual work area size is less than traditional office sizes, such as where the work area size is equal to or less than 6 feet by 6 feet.

The present invention relates to a system for subdividing building space, and more particularly relates to a reconfigurable apparatus including reconfigurable partition panels and furnishing components adapted to maximize floor space in a work area while also minimizing the footprint of the system and while maintaining the functionality and flexibility of the system.
A trend in modem offices and work environments is to reduce the size of individual offices and work areas, and to reduce the physical space that the apparatus forming the offices and work areas takes up (i.e., reduce their "footprint"). There can be many reasons to reduce the size of work areas, including increasing office density in order to reduce or control overall costs, to reduce individual workspace in order to free up space for group/team activities, and/or to provide office space or workspace for additional employees. However, as office sizes are reduced, particularly as office sizes are reduced to a 6-feet by 6-feet area or less, spacial problems are encountered. Efficient use of storage space and workspace becomes critical, as does user flexibility and control over organization of material and workflow. The work process must be designed to support natural and efficient storage of work papers in piles or folders, yet must allow the user to create context-specific work zones. One way of meeting this need is to provide custom-designed and custom-built furniture adapted for a particular use, but such custom furniture is not flexible and not reconfigurable, and thus is not satisfactory when an office or work area is reconfigured. Further, "old" furniture such as that used in the previous larger offices before the reconfiguration was done, either does not fit, or results in an oddly/inefficiently organized office having gaps around the furniture that are unusable or difficult to access. At the same time, it is not economically possible to offer customized furniture adapted to fit into each incrementally smaller size of office or work area, nor is it economically feasible to purchase new specially-sized furniture every time an office reconfiguration is done. Still further, the furniture construction should preferably provide for easy transition from personal to public workspace, but in a way making it easy to keep the office or workspace clean and neat, which presently known furniture often cannot do.
Traditional office furniture systems and also many "modern" office systems include a large worksurface, often 30-inches to 36-inches deep, for example. While a large worksurface allows the user to spread papers around, we have discovered that this large worksurface is not nearly as efficient as has been historically assumed. A reason is because a typical office worker only utilizes about 3 square feet (i.e., about 1 foot, 6 inches by 2 feet) in the center and front of the worksurface as a work area, and utilizes the remaining perimeter area (which can be 10 to 15 square feet in a 6-foot wide desk, for example) for storage of papers or other materials. The 10 to 15 square feet of storage area is not easily reachable. Further, all of the storage is horizontal, thus taking up valuable floor space, even though the stored papers and other materials may be used only for particular tasks. Often workers are forced to use smaller desks, the thought being that the smaller desks have all of the workspace needed for the workers and also have drawers for storage. However, the smaller desks do not have sufficient workspace for tasks that require multiple papers to be spread out, particularly if other items are also on the desk. Further, the drawers limit knee space, making the office restrictive and forcing a worker to work only from a center of the desk. Lighting can also be a significant problem, since small offices result in dark shadowy areas with limited room for chair movement and with limited visual access to files stored in low areas.
A particularly difficult and illusive problem with small offices is a feeling of crampedness and lack of room, and the related poor morale of workers who have to use such small offices. Many small offices, particularly offices of 6 feet by 6 feet and smaller are noticeably tight and difficult to maneuver in, such that workers prefer not to spend time in them. Further, existing furniture can undesirably limit the workers' ability to customize or specialize their office to satisfy the need of a natural workflow. These problems are exacerbated by many factors, including office arrangements that physically partially enclose or trap the worker in the office, office arrangements that provide poor visual or physical access to storage areas, furniture that is not multifunctional and/or not flexible or reconfigurable for optimal efficiency and natural work flow, and in particular a work arrangement that does not provide an efficient workspace-to-storage-space logic.
Accordingly, a furniture construction solving the aforementioned problems is desired.

Reconfigurable system for subdividing building space and having minimal footprint


The present invention provides an insect or arthropod pesticidal composition. The composition includes active ingredients having a mixture of fatty acids, each of the fatty acids having a straight carbon chain from 6 to 12 carbon atoms long. The fatty acid mixture includes a first fatty acid molecule having a straight carbon chain from 6 to 8 carbon atoms long, and a carboxylic acid group. The fatty acid mixture also includes a second fatty acid molecule having a straight carbon chain from 8 to 12 carbon atoms long, and a carboxylic acid group. The composition also includes a carrier that promotes adherence or absorption or transport across the surface of insects or arthropods to effect their incapacitation or death.

Mosquito borne diseases include malaria, yellow fever, and dengue fever. Malaria occurs in over 100 countries and approximately 40% of the world's population is at risk. According to the CDC, more than 1 million deaths each year are caused by malaria, mostly small children in African areas south of the Sahara. Ticks can transmit encephalitis, Lyme disease and Typhus fever. Filariasis can be transmitted by blackflies, leishmaniasis by sandflies, sleeping sickness by Tsetse flies, and Chagas disease by assassin bugs. Lice can spread typhus fever and fleas are the well-known vector for plague. While the common house fly (Musca domestica) does not bite, it can transmit typhoid fever, cholera, dysentery, pinworms, hookworms, and certain tape worms. Stable flies (biting house flies) can also transmit filth-related disease. Reducing bites or reducing fly landings reduces the chances of getting these diseases, and insect repellents (e.g. DEET or N,N-diethyl-m-toluamide) are recommended for this purpose.
Insecticides (e.g. pyrethrum or permethrin) used as sprays or bed-net impregnants also reduce bites. DEET is effective in repelling mosquitoes, but it is a poor fly repellent. Its efficacy against mosquitoes is limited to a few hours duration by high evaporative loss from the skin surface (about 70% of applied dose) and also by significant absorption into the skin (approximately 20%). The usefulness of permethrin for insect control rests largely on its ability to cause incapacitation and death after insects make contact with treated surfaces or sprays; its low vapor pressure (about 10−8 mm Hg@20° C.) makes it relatively useless as a repellent. Permethrin's insecticidal properties are maximized in emulsion formulations; however, these formulations also maximize skin absorption (about 30%) and human skin contact should be avoided. Permethrin's efficacy has been reduced by insect resistance (Saaverdra-Rodriguez, K., C. Strode, A. F. Suarez, I. F. Salas, H. Ranson, J. Hemingway and W C. Black IV. Quantitative Trait Loci Mapping of Genome Regions Controlling permethrin resistance in the mosquito Aedes aegypti. Genetics, 180: 1137-1152, 2008).
Blood-sucking insects use a variety of physical and chemical cues to seek out a host. Their behavior can also be modified by emissions or pheromones from themselves or other species. A better understanding of the chemical-mediated behavior has lead to the development of alternate control measures, such as mating disruption.
A variety of factors and chemicals, including fatty acids, have been implicated or suggested as mosquito host attractants, and the literature contains many contradictory reports. Brown lists a number of factors involved in the attraction of mosquito to humans (in order of importance): moisture, convective heat, carbon dioxide, movement, contour or increase in black-white interfaces, and reflectivity (Brown A. W. A., H. P. Roessler, E. Y. Lipsitz and A. G. Carmichael. Factors in the attractiveness of bodies for mosquitoes. The Canadian Entomologist 96:102-103, 1964).
Since 1995, we have been investigating fatty acids as repellants or biopesticides against insects and arthropods of medical or economical importance and acknowledge past support from the USDA (Reifenrath, W G. Natural Fly Repellent for Livestock. SBIR Phase II Final report, CSREES Award No. 2003-33610-13044, Feb. 1, 2007), US Army (Reifenrath, W G. Development of an Insect Repellent Based on Human Skin Emanations. Final Report, DAMD17-96-C-6046, October, 1996), and DoD (Reifenrath, W G. New Repellent Combination against Flies and Mosquitoes. Final Report, USAMRMC Award No. W81XWH-04-1-0787, Final Report, December 2006). Our approach has been utilitarian; that is, to first focus on low-cost formulations that had a reasonable chance of regulatory approval and to demonstrate that these formulations were effective in laboratory (Mullens, B A, Reifenrath, W G, and Butler, S M. Laboratory repellency trials of fatty acids against house flies, horn flies, and stable flies (Diptera: Muscidae). Pest Management Science, 65: 1360-1366, 2009; Reifenrath, W G. Natural Insect and Arthropod Repellent. U.S. Pat. No. 6,306,415 B1, Oct. 23, 2001) and field studies for insect control (Chansang, U. and Mulla, M. S. Field Evaluation of repellents and insecticidal aerosol compositions for repelling and control of Siphunculina funicola (Diptera: Chloropidae) on aggregation sites in Thailand. J. Am. Mosq. Control Assn. 24: 299-307, 2008; Reifenrath, W G. Natural Fly Repellent for Livestock, Stratacor, Inc. http://www.reeis.usda.gov/web/crisprojectpages/200581.html). Stratacor has an application approved by the U.S. EPA for a formulation of three medium chain fatty acids (octanoic, nonanoic, decanoic acids, trademarked C8910) for fly and lice control on cattle, as well as an approval for use of the three fatty acids on food commodity animals (Anonymous. Application to Register C8910 Fly Repellent Oil, Stratacor, Inc., Richmond Calif., Jan. 18, 2008; Anonymous. Notice of Pesticide Registration, C8910 Fly Repellent Oil, EPA Reg. No. 84893-1, Biopesticides and Pollution Prevention Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C., Oct. 13, 2009; Anonymous. Notice of Filing of a Pesticide Petition for Residues of Pesticide Chemicals in or on Various Commodities. US Environmental Protection Agency, Federal Register, Vol. 73, No. 54, Wednesday, Mar. 19, 2008; Anonymous. Memorandum, Tolerance Exemption Petition for the Active Ingredients C8-C10 n-carboxylic acids (octanoic acid, nonanoic acid, and decanoic acid), Biochemical Pesticides Branch, Biopesticides and Pollution Prevention Division, US Environmental Protection Agency, Washington, D.C., Oct. 8, 2009). These fatty acids have been approved by the US FDA as food additives (flavors) in the U.S. since 1965 and are categorized as "Generally Recognized as Safe". C8910 can be formulated for direct use on the skin, and a topical formulation is being advanced for human use in Africa. However, user compliance with topical repellents, even in the U.S. military, is low (about 30%). Therefore, our long term goal is to advance safe and cost-effective C8910 formulations for both direct skin application and area treatments or space sprays to control the spread of malaria by the Anopheles mosquito, filth related disease by house and stable flies, and tick borne diseases. The fatty acids comprising C8910 are inexpensive commodity chemicals that come from palm kernel oil or coconut oil (as a byproduct of coconut production) and from cattle tallow. These compounds could eventually be produced in developing countries.
Fatty acids of chain length 8 (caprylic or octanoic) to 11 (undecanylic acid) were reported to be toxic to house fly larvae (Quraishi, M. S. and A. J. Thorsteinson. Toxicity of some straight chain saturated fatty acids to house fly larvae. J. Econ. Entomol. 58: 400-402, 1965). The fatty acids octanoic, nonanoic, and undecylenic were found to have ovicidal activity against eggs of Aedes aegypti; the author suggested that the fatty acids exerted a "smothering" effect or interference with respiration (Cline, R. E. Lethal effects of aqueous formulations containing fatty amines or acids against eggs and larvae of Aedes aegypti. J. Econ. Entomol. 65: 177-181, 1972). The straight chain fatty acids (C7 to C11, but not C12) were found to be toxic to Aedes aegypti instar IV larvae and pupae (Quraishi, M. S. and A. J. Thorsteinson. Effect of synthetic queen substance and some related chemicals on immature stages of Aedes aegypti. J. Econ. Entomol. 58: 185-187, 1965). Caproic (C6) through capric acid (C10) were found to have optimal larvicidal activity for housefly larvae, with declining activity for undecanoic acid (C11) and lauric acid (C12) (Levinson, Z. H. and K. R. Simon Ascher. Chemicals affecting the preimaginal stages of the housefly. Rivista DI Parassitologia. 15: 111-119, 1954).
We have shown that C8910 is an effective mosquito repellent for use on the skin, and can also repel ticks, biting flies and significantly reduce the number of fleas and lice on animals. As a vapor phase repellent against mosquitoes, a number of straight and branched chain fatty acids have activity in olfactometer tests with Aedes aegypti mosquitoes (FIG. 1), with C8, C9, and C10 sitting at or near the top of the repellency "dome". As frequently seen in homologous series of insect repellents (Skinner, W. A. and Johnson, H. L. The design of insect repellents. In: Drug Design, Vol. 10, E J Ariens, Ed., Academic Press, New York, pp. 277-305, 1980), activity at lower chain length is limited by lack of persistence due to high volatility. Activity at higher chain length is limited by lack of volatility, as mosquito repellents are required to have a minimum effective evaporation rate (Reifenrath, W. G. and Robinson, P. B. In Vitro Skin Evaporation and Penetration Characteristics of mosquito repellents. J. Pharm. Sci, 71:1014-1018, 1982; Reifenrath, W. G. and Spencer, T. S. Evaporation and penetration from skin. In: Percutaneous Absorption Mechanisms Methodology Drug Delivery, R L Bronaugh and H I Maibach, Eds., 1st Ed., Marcel Dekker, New York, pp. 305-325, 1985).
The fatty acids comprising C8910 can penetrate the skin after topical application and can also "back diffuse" or reach the skin surface after application to the visceral side of the excised skin (Reifenrath, W. G. Unpublished data, Stratacor, Inc., December, 2005-February, 2006). However, these compounds are not effective insect repellents after oral administration to cattle (Personal Communication, David Boxler, Dept. of Entomology, University of Nebraska West Central Research and Extension Center, North Platte, Neb., Jun. 27, 2006), as they are metabolized too quickly to be excreted via the skin (Van Den Driessche, M., K. Peeters, P. Marien, Y. Ghoos, H. Devlieger, and G. Veerman-Wauters. Gastric emptying in formula-fed and breast-fed infants measured with the 13C-octanoic acid breath test. J. Pediatr. Gastroenterol. Nutr. 29: 46-51, 1999).
While conducting field studies on livestock, we were surprised to find that dusting cattle with C8910 offered protection (about 90% reduction in total body fly counts) against biting (horn) flies equal to the organophosphorus insecticides coumaphos (Co-ralR) and tetrachlorvinphos (RabonR) (FIG. 2). These results have been reproduced by different investigators at different locations where temperature and humidity are high. In this type of test, C8910 was formulated as a dust and cattle self-treated by walking under a dust bag en-route to water. If C8910 were acting just as a repellent, the flies would simply have moved from the treated area (back) to the untreated areas (belly and legs), resulting in no net reduction in fly count. A direct toxic effect of C8910 on the flies could account for the efficacy, but this was not obvious at the time of the test. This prompted a laboratory examination of the incapacitative and toxic effects of C8910 on Aedes aegypti mosquitoes, which showed that direct contact (aqueous suspension of C8910 wettable powder on treated filter paper in Petri dishes) caused incapacitation in 10 minutes at a dose of 4.7 ug/cm2, in 25 minutes at a dose of 2.35 ug/cm2, and while a still lower dose of 1.18 ug/cm2 did not cause incapacitation, it stopped spontaneous movement of mosquitoes, with negative consequences for mating and reproduction. Qualitatively similar activity was found in laboratory studies with house flies, stable flies, and horn flies (FIGS. 3-10), with house flies being least sensitive to the incapacitative and toxic effects of C8910. An initial report indicated that the Tsetse fly was not repelled by C8910 dust formulations (Personal Communication, Serap Aksoy, Dept. of Epidemology and Public Health, Yale School of Medicine, New Haven, Conn., Apr. 21, 2003), but a later report showed that a 15% mineral oil and an 0.3% wettable powder dispersion were effective in incapacitating or killing the Tsetse fly (Personal Communication, Brian Weiss, Dept. of Epidemology and Public Health, Yale School of Medicine, New Haven, Conn., Aug. 3, 2009). Tsetse fly repellency may have been compromised by incapacitation, an effect that was not appreciated until recently. In tests conducted in free choice cages as described by Mullens et al. (Mullens, B A, Reifenrath, W G, and Butler, S M. Laboratory repellency trials of fatty acids against house flies, horn flies, and stable flies (Diptera: Muscidae). Pest Management Science, 65: 1360-1366, 2009), the German cockroach became incapacitated and then died after roaming into floor areas treated with 15% C8910 in attapulgite clay (FIG. 11).
We have found that incapacitative and toxic effects of fatty acids on mosquitoes are highly dependent on the type of fatty acid and the formulation. When moisture is introduced in the form of aqueous dispersions of powder formulations, house fly and mosquito incapacitation and death result. Likewise, with mineral oil formulations. Both of these formulations enhance the mammalian skin absorption of C8910 and likely enhance fly uptake and absorption. Formulations made from emulsifiable concentrates (EC) promote skin absorption and enhance fly toxicity of permethrin (Reifenrath, W G. Enhanced skin absorption and fly toxicity of permethrin in emulsion formulation. Bull. Environ. Contam. Toxicol. 78: 299-303, 2007). Likewise, formulations of C8910 in EC cause house fly and mosquito toxicity. The well-known insecticidal properties of soaps (sodium or potassium salts of fatty acids), where the fatty acid is ionized at basic pH, is probably due to a different mechanism related to surfactant effects. Indeed, the ionic and non-ionic surfactants contained in an emulsifiable concentrate vehicle for permethrin (Evercide emulsifiable concentrate without permethrin, MGK Corp, Minneapolis) had no fly incapacitative effects. Incapacitation was not simply due to acidic pH, as lactic acid, a low molecular weight carboxylic acid, was nontoxic to flies in these assays. Lauric acid, with increased carboxylic acid carbon chain length beyond those comprising C8910, was also non-toxic in EC formulation. The insect repellent DEET did cause fly and mosquito mortality after 24 hours at 47 ug/cm2 (the fatty acid dose that caused 100% immediate fly and mosquito incapacitation and 80-100% mortality at 24 hours), but by a mechanism that did not involve immediate incapacitation. As a test of a sodium ion channel blocker, freshly prepared aqueous emulsions of lidocaine free base (47 ug/cm2) or 15% concentration in mineral oil did not cause fly incapacitation in these assays. At a dose of 4.7 ug/cm2, permethrin caused irreversible fly and mosquito incapacitation, while the same low dose of C8910 showed reversible incapacitation against the stable fly and horn fly (FIGS. 9,10).
Observationally, the fatty acids comprising C8910 appear to have a selective repellent and/or toxic effect against mosquitoes and a variety of other flies, as spiders, bumble bees, honey bees, and wasps are unaffected. Ticks (Ixodes pacificus or Dermacentor) placed in the barren center of free choice cages and allowed to roam into quadrants of C8910 laden granules or carrier-only treated quadrants typically get within ½ inch of the repellent granules, do an about-face, and proceed into and through control areas and climb the walls of the cage, when they were captured by the investigator and placed back into the starting center. Occasionally, a tick will wander between repellent granules, and no longer having a choice between repellent and non-repellent areas, may continue to wander aimlessly in contact with the repellent, until it stopped all movement and eventually died. Forced exposure of ticks (Ixodes pacificus) to a 0.3% formulation of C8910 in Kaolin-P water dispersion for 10 minutes in a Petri dish resulted in 50% incapacitation, 100% incapacitation in 40 minutes and 100% mortality in 24 hours. No incapacitation or toxicity was observed with control (kaolin clay water dispersion) over 24 hours. A similar type of behavior was observed with the German cockroach, as noted above (FIG. 11). While these are descriptive accounts, they go to the heart of the proposed mechanism of fatty acid toxicity to susceptible insects—an indirect effect based on interference with the insect's ability to navigate, giving the appearance of death before actual death (the "living dead" or paralysis syndrome). At low levels comparable to natural pheromone concentrations, the fatty acids of C8910 may actually be attractive, and this has been observed with ants. Higher air concentrations of subject fatty acids may overload sensory mechanisms, and insects are repelled. If C8910 is forced into contact with susceptible insects in a spray formulation that promotes adherence to the insect or absorption by the insect (in effect surrounding the insect with C8910), reversible incapacitation may result at lower doses to the insect. At higher doses, the incapacitation becomes irreversible and the insect eventually dies.

Pesticidal compositions for insects and arthropods


A server computing device generates training data based upon an identifier for a device, a timestamp, and a label received from a developer computing device. The server computing device trains a computer-implemented machine learning (ML) model based upon the training data. The server computing device also generates client configuration data for the ML model that specifies transformations that are to be applied to values in order to generate input values for the ML model. The server computing device deploys ML assets to client computing devices, the ML assets comprising the ML model and the client configuration data. The client computing devices execute the ML model using input values derived via transformations of (local) values produced by the client computing devices and transmit telemetry data to the server computing device. The server computing device updates the ML assets based upon the telemetry data.

Machine Learning (ML) is a category of computer-implemented technologies that enable a computing device to make predictions and/or inferences based upon values of features, wherein a developer need not explicitly specify how the values of the features relate to the resultant predictions. ML technologies are useful in situations where it is difficult to develop a conventional rules-based algorithm for making predictions and are becoming increasingly important in the development of software applications.
Conventionally, for a software developer to include ML-based functionality into a target application, the software developer identifies a type of ML model (e.g., a neural network, a regression tree, etc.) that is to be integrated into the target application. For instance, the developer may identify an output (i.e., a prediction) of the (to-be-generated) ML model, determine semantics about the actual meaning of the output, and then determine what input features to the ML model might be useful in producing the desired output. The developer can determine, based upon his/her intuition and experience, what type of ML model is most appropriate. The developer then determines features (sometimes referred to as "predictors") upon which the ML model is to be trained. Conventional software development platforms often fail to provide access to requisite training data for the ML model, wherein the training data includes a labeled output and values for the features upon which the ML model is to be trained. Accordingly, in enterprise settings, the developer may be forced to initiate a data collection program to allow for collection and labeling of data. Moreover, conventional software development platforms fail to provide technologies that can transform collected data into features desired by the developer. In an example, a feature of interest to the developer may be "number of mouse clicks over the last five minutes." While collected data may include mouse clicks and timestamps corresponding thereto, the collected data does not explicitly include the feature of interest to the developer; conventional software development platforms require that the developer construct an algorithm to transform collected data into values for features of interest.
Once a sufficient amount of training data has been acquired, a computing system trains the ML model based upon the training data. Once trained based upon such training data, the ML model, when provided with values for the features, outputs a label (i.e., a prediction) that is based on the values of the features. The computing system may evaluate performance of the ML model using evaluation data, and the developer may modify the ML model (e.g., by retraining the ML model with different training data, adding or removing features that are provided as input to the ML model, etc.) based upon his/her intuition and experience (or an application that provides an automated exploration) in an attempt to improve performance of the ML model such that the NIL model is more likely to output correct predictions.
As indicated above, conventional software development platforms suffer from various deficiencies with respect to constructing, deploying, and updating ML models. First, conventional software development platforms rely on the developer to have knowledge of ML model types, how ML models are trained, etc. For instance, conventionally, the developer must (without assistance) identify features that are to be used to train the ML model, transformations that are to be applied to collected data to obtain values for the features prior to training or evaluating the ML model, parameters of the ML model (e.g., a number of hidden layers in a Deep Neural Network, a number of branches in a regression tree, etc.), generate or identify ML libraries/runtimes to execute on client computing devices, and so forth. While certain applications have been developed that automate maintenance of ML runtimes/libraries, such applications do not include functionality that enables an ML model to be trained without the developer specifying at least some features. Second, certain features may be of high predictive value but may not be readily accessible to the developer and/or may not easily identified as relevant by the developer.
Third, when the ML model is deployed (e.g., placed on a client computing device operated by an end user), values for features that are to be provided as input to the ML model may not be readily available. Put differently, a log file generated by an operating system of the client computing device may include values for a first set of features; however, the ML model is not configured to receive values for the first set of features. Instead, the ML model may be configured to receive, as input, values for a second set of features that are derivations of the first set of features. Conventional software development platforms fail to provide technologies that assist the developer with transforming the first set of features into the second set of features when the ML model is deployed on client computing devices. As a result, conventionally, developers must implement their own retrieval and transformations for features, which can be error prone as it is difficult to ensure that features used in training the ML model match input features to the ML model when the ML model is deployed and evaluated in the context of a target application.
Fourth, conventional approaches for incorporating a ML model into a software application tend to require retrieval, processing, and transformation of features that have fixed definitions within the program code of the software applications. The program code tends to be separate from the code used to produce the feature set that is used to train the ML model. As a result, changes (e.g., additions, deletions) to the feature set require changes to the program code, which then has to be validated and deployed to client computing devices. This conventional approach is limiting and problematic as it does not provide a way to maintain consistent feature selection, processing, and formatting between the training inputs and the inputs used at run time. Moreover, having to change program code in order to change the feature set limits the ability to rapidly deploy and experimentally validate test variations of the feature set, or various candidate models which require differences in the feature set. The conventional approach is even more problematic when the ML model is trained on a server computing device (e.g., on a cloud-based computing platform), but deployed and used on client computing devices, as it is challenging to ensure that consistent feature engineering occurs on both the server-side and the client-side. Because of the aforementioned deficiencies, adoption of ML technologies in target applications has been slower than would otherwise be possible.

Computing system for training, deploying, executing, and updating machine learning models