An example method includes decreasing the pressure within at least one tire of a vehicle when the vehicle is moving. The decreasing is in response to a condition change. An example assembly includes a sensor and a tire pressure controller that causes a decrease in a pressure within at least one tire of a vehicle in response to a first condition detected by the sensor.

This disclosure relates to adjusting tire pressure in a vehicle.
Example hybrid vehicles include hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Generally, hybrid vehicles differ from conventional motor vehicles because hybrid vehicles are selectively driven using a battery-powered electric machine. Conventional motor vehicles, by contrast, rely exclusively on an internal combustion engine to drive the vehicle.
Improving fuel economy is desirable for all vehicles, especially hybrid vehicles. Improvements to fuel economy typically focus on the powertrain efficiency and aerodynamic efficiency.

Tire pressure adjustment system and method


A data processing system augments compression of non-zero values of significant coefficients by coding entries of a significance map independently of coding the values of significant non-zero coefficients. A dedicated symbol represents a zerotree structure encompassing a related association of insignificant coefficients within the tree structure. The zerotree symbol represents that a coefficient is a root of a zerotree if, at a threshold T, the coefficient and all of its descendants that have been found to be insignificant at larger thresholds have magnitudes less than threshold T. The zerotree structure is disclosed in the context of a pyramid-type image subband processor together with successive refinement quantization and entropy coding to facilitate data compression.

Among the primary objectives of a digital data compression system are the removal of redundant information and the accurate representation of remaining information using a minimum number of bits, before the data is conveyed via a transmission channel or storage medium. Data to be compressed may represent various types of information, such as audio and video information for example.
Coding of data for compression often requires that two factors be considered in particular, namely, the location of significant data and the value of significant non-zero data. Compression coding of data locations, which may be represented by the entries of a so-called significance map, advantageously augments the coding of the significant non-zero data.
Recent developments in the field of image signal processing, among others, continue to focus attention on a need for efficient and accurate forms of data compression coding. In this regard various forms of so-called "pyramid" signal processing have been proposed, particularly in the context of image information processing. Multiresolution "pyramid" processing of image data is described, for example, by Burr et al. in "The Laplacian Pyramid as a Compact Image Code", IEEE Transactions on Communications, Vol. Com-31, No. 4, April 1983. A so-called "wavelet" pyramid is a specific type of multiresolution pyramid that uses quadrature mirror filters (QMF) to produce subband decompositions of an original image representative video signal. A signal processor of this type is described by Pentland et al. in "A Practical Approach to Fractal-Based Image Compression", Proceedings of the DCC '91 Data Compression Conference, Apr. 8-11, 1991, IEEE Computer Society Press, Los Alamitos, Calif. The Pentland et al. compression system attempts to use low frequency coarse scale information to predict significant information at high frequency finer scales. QMF subband pyramid processing also is described in the book "Subband Image Coding", J.W. Woods, ed., Kluwer Academic Publishers, 1991.
Another system for pyramid processing image data is described by Lewis et al. in "A 64 Kb/s Video Codec Using the 2-D Wavelet Transform", Proceedings of the DCC '91 Data Compression Conference as mentioned above. Lewis et al. describe a coding system based on a model of human visual perception. Decomposed high pass bands are coded by constructing spatially local trees having nodes comprising2.times.2 blocks of subtrees. The energy (a statistical measure) of a tree is compared with a human visual system weighted threshold to determine if a tree is important or not. If not, the coder assumes that the remainder of the tree if zero and a "zero flag" is sent.
A data compression system disclosed by J.M. Shapiro in a copending U.S. patent application Ser. No. 790,860 uses the absence of significant low frequency coarse scale information to predict the absence of significant information at higher frequency finer scales, in contrast to the Pentland et al. system which conversely attempts to predict significant information. In addition, the Shapiro system advantageously does not rely upon a statistical measure, such as energy, associated with a block of plural coefficients as in Lewis et al., since such reliance may lead to a significant coefficient being obscured by surrounding insignificant coefficients. Also unlike Lewis et al., the Shapiro system guarantees that for a given threshold neither a root element of a tree structure nor any descendant of a root element has a magnitude greater than the threshold.
It is herein recognized that a variant of the Shapiro system, as disclosed herein, can result in improved coding performance, albeit at the expense of an increase in memory and computation In the zerotree structure of the previously mentioned Shapiro system, a large significant coefficient value occurring at an intermediate (leaf) node in the tree structure would prevent the node ancestors from being a zerotree root in future evaluations at progressively smaller thresholds, e.g., in association with a successive approximation quantizer. In the system disclosed herein, using a successive approximation quantizer, once a coefficient is found to be significant, it is no longer necessary to include it in significance maps at smaller thresholds. Thus in accordance with the principles of the present invention, a significant coefficient found at an intermediate (e.g., leaf) node does not prevent an ancestor (at a coarser level) from being a zerotree root on future evaluations at smaller thresholds.

Data compression system including successive approximation quantizer


A method for manufacturing a semiconductor device, in which a substrate is disposed in a chamber and a fluorine-containing silicon oxide film is formed on the substrate using a plasma CVD process. The fluorine-containing silicon oxide film is formed such that the release of fluorine from this silicon oxide layer is suppressed. According to this semiconductor device manufacturing method, a stable semiconductor device can be provided such that the device includes a fluorine-containing silicon oxide film (FSG film) at which the release of fluorine is suppressed, and thus peeling does not occur.

1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device including a silicon oxide film (which film will be sometimes referred to hereafter as an "FSG film") containing fluorine (F), which film serves as an inter-layer insulation film or the like, and more particularly to a method of manufacturing a semiconductor device in which an FSG film is formed by a CVD (chemical vapor deposition) process.
2. Description of the Related Art
Recently, among low-dielectric constant materials which are required as films between layers of metal wiring, FSG films formed by a plasma CVD process have attracted attention. Of these low-dielectric constant materials, FSG films formed by the plasma CVD process undergo relatively little degasification, and are stable films. Moreover, these FSG films have excellent characteristics with regard to filling in of narrow slits.
A process flow for a conventional semiconductor device is shown in FIGS. 10A to 10H.
A metal lamination film 13 is formed by a sputtering process on an insulating layer 12, which is formed on a substrate 11 which includes an unillustrated transistor (FIG. 10A). At the metal lamination film 13, for example, an aluminium alloy 13a and a high melting point metal 13b are layered. Patterning is carried out at this metal lamination film 13, and metal wiring 14 is formed (FIG. 10B). Then, an FSG film 15 of, for example, 1000 nm is formed on the metal wiring 14 and the exposed insulating layer 12 by, for example, a plasma CVD process (FIG. 10C). Thereafter, a surface of the FSG film 15 is levelled by a CMP (chemical and mechanical polishing) process. To suppress the release of fluorine (F) at this time (that is, to prevent fluorine degasification), a silicon-rich film of silicon oxide of, for example, 200 nm is formed to serve as a cap film 16 by, for example, a plasma CVD process (FIG. 10D). Then, through-holes 17 are opened through the FSG film 15 and the cap film 16 (FIG. 10E). After this, a TiN film 18 of, for example, 50 nm is formed on the cap film 16 and hole portions at the through-holes 17 by a sputtering process or CVD process (FIG. 10F). Thereafter, a W (tungsten) film 19 is formed by a CVD process so as to completely fill in the through-holes 17 (FIG. 10G). Finally, the TiN film 18 and the W film 19 are removed by a CMP process except at portions corresponding to the through-holes 17 (FIG. 10H). These steps are repeated a desired number of times, and then heat treatment is performed at around 400° C. in an atmosphere including, for example, H2· Damage is repaired, the first wiring 14 (an aluminium alloy film) is stabilized, and thus a semiconductor device with a multi-layer wiring structure is completed.
However, it has been found that degasification of a portion of the fluorine included in the FSG film occurs, and this fluorine is released. Thus, for example, peeling of the cap film from the FSG film and the like, leading to detachment of wiring peripheries, may occur. Some of this fluorine may be trapped due to the formation of the cap film. However, in the recent semiconductor devices, as the number or layers becomes greater, the total thickness of FSG films increases and the number of heat treatments increases, fluorine degasification cannot be completely prevented, and film peeling at peripheries of the wiring occurs. Furthermore, if the cap film is made thinner, then the effects of fluorine trapping is reduced due to the thinning of the film, when the W film is removed by the CMP process. If the cap film is made thicker, there are problems with an increase of inter-layer volume, etching accuracy and the like. Therefore, it is required that fluorine degasification be suppressed at the FSG film itself and/or that the effect of fluorine trapping by the cap film be enhanced.

Method of manufacturing semiconductor device


One embodiment of the invention sets forth a technique for avoiding collisions between agents traversing different lanes of a multi-lane path in a crowd simulation. A perception data structure is maintained per agent that keeps track of the speeds and locations of neighboring agents in the crowd simulation. At each frame, the perception data structure corresponding to a particular agent is analyzed to identify any projected collisions. If the perception data structure indicates that the agent is projected to collide with another agent, then a collision avoidance operation is executed to avoid the collision.

1. Field of the Invention
The invention relates generally to the field of computer animation and, more specifically, to dynamic collision avoidance for crowd simulation using lane coordinates.
2. Description of the Related Art
Crowd simulation is the process of simulating a crowd having a large number of animated characters placed in a computer-generated crowd area. For the characters in the crowd to appear realistic, crowd simulators typically provide algorithms that attempt to simulate movements of the characters in a realistic manner. Such movements include the characters in the crowd traversing pre-defined paths. Crowd simulators, however, do not account for characters in a crowd colliding with one another when traversing paths. Thus, characters in a crowd simulation often collide with one another when traversing intersecting paths.
Collisions between characters negatively impact the realism of the crowd simulation because humans, in real life, self-correct their motion to avoid these types of collisions. Therefore, simulations generated by a crowd simulator that do not account for collisions between the different characters in the simulations appear unrealistic.
As the foregoing illustrates, what is needed in the art is a technique that enables collisions between moving objects in a crowd simulation to be avoided.

Dynamic obstacle avoidance for crowd simulation using lane coordinates


An agitator for providing uniform and rapid material mixing is provided comprising a first sweep blade mechanically coupled to a second sweep blade. The first sweep blade extends from a first sweep blade origin to a first sweep blade terminus along a first substantially helical path defined about a first helical axis. The second sweep blade extends from a second sweep blade origin to a second sweep blade terminus along a second substantially helical path defined about a second helical axis. The respective orientations of the first sweep blade along the first substantially helical path and the second sweep blade along the second substantially helical path define a first flow direction extending from the first sweep blade origin to the second sweep blade terminus. An agitator assembly is provided comprising a first agitator, a second agitator, a mixing bowl enclosing the first and second agitators, and a driving assembly coupled to the first and second agitators. The second agitator is oriented substantially parallel to the first agitator. The first agitator defines a first flow direction extending from the first sweep blade origin to the second sweep blade terminus. The second agitator defines a return flow direction extending from the third sweep blade origin to the fourth sweep blade terminus. The return flow direction is opposite the first flow direction.

The present invention relates to an agitator and an agitator assembly for mixing materials. More particularly, the present invention relates to dough mixing and an agitator designed to provide for more uniform and rapid dough mixing within a mixing bowl.
FIG. 5 illustrates a conventional agitator assembly 2 comprising a pair of agitator shafts 4 and a set of sweep blades 6 mounted thereto. The shafts are caused to rotate in a mixing direction 8. Unfortunately, some mixing discontinuities may occur in the prior art agitator assembly 2 because the flow of material in the vicinity of the agitator assembly 2 tends to be focused at the center of the agitator assembly, see directional arrows 3. Material at the periphery of a mixing bowl in which the agitator assembly 2 is positioned is under mixed and material at the center of such a mixing bowl is over mixed. Further, the focused flow is not conducive to an efficient and rapid mixing operation.
Accordingly, there is a need for an agitator and an agitator assembly that ensures that materials are mixed uniformly throughout the mixing bowl. There is also a need for an agitator design that yields improved mixing rates within a mixing bowl.


A utensil support assembly as mounted on a building sidewall with one offset bar adapted to support a plurality of utensils. The horizontally aligned, utensil support bar is anchored close to each longitudinal end by a bracketing set also adapted to be wall mounted at its flanged longitudinal ends. The flattened apexes of each bracket element are flanged and sized to provide a passageway for the bar shaft while they are nested.

In active workplaces, like the kitchens of commercial restaurants, the turnover of many utensils is cyclical. As quickly as pans and pots are used, sanitized, and exposed to fast ambient air drying. They are relocated for quick re-use, which site must be seeable and reachable. Open wall space in a commercial kitchen is often wasted space, unless it can be adapted to employ the hangable utensil means of the present invention.


The navigation apparatus in a vehicle receives physical condition data regarding user's condition from a measurement instrument through a power line when the vehicle is connected to the power line. The navigation apparatus determines whether a travel condition of the vehicle that is driven by using the sensors disposed in the vehicle, in terms of the driving operation concerning the fuel consumption rate of the vehicle. If the driving operation is not determined as fuel-consumption-conscious, an advice for the driving operation is output from the navigation apparatus according to the physical condition of the user. The user thus can have an appropriate advice for the driving operation that improves the fuel consumption rate of the vehicle at an appropriate timing that takes into consideration of the physical condition of the user under measurement outside of the vehicle.

In recent years, a driving support system that uses sensors and/or equipments in a vehicle for collecting a travel condition data of the vehicle and outputs an advice for driving operation for a user based on the collected data is proposed, for example, in Japanese patent document JP-A-2001-256036 (e.g., paragraphs [0025], [0052] etc.)
Also, in recent years, electric vehicles and hybrid vehicles connected to an outlet at home by using a plug for charging the battery are considered as a subject of research and development. While the battery in the vehicle is charged by the electricity provided through the power line, a device outside of the vehicle and a vehicular equipment is connected through a power line communication for data exchange, in a technique disclosed, for example, Japanese patent documents JP-A-2003-23378, and JP-A-2003-23442.
In the technique in the above document (JP-A-2001-256036), the vehicle's travel condition collected by the equipment is used to determine/notify a degree of safeness of the travel condition, and to provide an advice for improving the safety of the travel condition.
Therefore, the user may be able to improve the fuel consumption rate if he/she takes the provided advice and reflects the advice to the driving operation for decreasing the frequency of the abrupt acceleration/deceleration/braking. Further, if the fuel consumption rate is improved, that leads to a favorable condition for the environmental issues such as a global warming due to the reduction of the carbon dioxide exhausted as the exhaust gas from the vehicle.
However, if the advice for the driving operation is provided too frequently, the user may feel it uncomfortable. On the other hand, the frequently-provided advice may be beneficial if the user is, for example, in a physically bad condition and is having a deteriorated condition in terms of attentiveness.
Therefore, in the technique in the above document (JP-A-2001-256036), providing the advice at an appropriate timing was the problem. In particular, the appropriate determination whether the user is having a bad physical condition or a good one was difficult because the appropriate determination should be based on the examination performed at a time when the user is resting. That is, in other words, the user in the vehicle is not resting, thereby making it difficult for appropriately determining the physical condition of the user in an accurate manner.


A constant velocity joint boot assembly has a boot can connected to an outer race of the joint. The boot can receives a portion of a boot. The thickness of the boot may be changed in different areas to result in different boot performances. A sleeve is connected to the inner race. A portion of the sleeve may have a complementary shape to a portion of the boot, also to result in different boot performance. A clamp may be located over a portion of the boot to secure it to the sleeve.

Boots are well-known devices used to enclose an end of a constant velocity joint. Boots keep out dirt, debris and moisture from the joint and keep lubricant in the joint.
One example of a prior art boot 10 for a joint 12 is depicted in FIG. 1. The joint 12 comprises an inner race 14, an outer race 16, a cage 18 and at least one ball 20 within the cage 18.
The boot 10 encloses one end of the joint 12. The boot 10 is connected at one end to the outer race 16 with a boot can 22. A boot bead 26 is formed on the boot can 22 to capture the boot 10. The boot bead 26 is generally round and formed inwardly. A boot can crimp 28 also helps hold the boot 10 in place. The boot can crimp 28 is also formed inwardly. The boot 10 is connected at the other end to a shaft 24, such as by a clamp 30.
The size of the boot 10 used in FIG. 1 is characterized by boot length L, boot can length LL, boot can inner diameter Ø Db and the thickness of the boot 10. Boot length L, boot can length LL and boot can inner diameter Ø Db are determined by the required maximum static articulation angle capability, which is depicted in FIG. 2. More particularly, boot length L is determined in a way that boot length L in a joint assembly state as shown in FIG. 1 is equivalent to the boot length of an extended boot region 32 and the boot length of a contracted boot region 34 at a maximum joint angle.
Boot thickness for the boot 10 of FIGS. 1 and 2 is depicted in FIG. 3. The boot 10 generally has a round shape RR with an angle α from the horizontal, where the thickness T1 of an upper slope portion 36, is equal to the thickness T2 of a concave portion 38, which is equal to the thickness T3 of a lower slope portion 40. The joint boot thickness T1, T2, T3 is determined by taking into consideration boot radial and axial stiffness related to potential high risk boot failure modes, such as boot inversion and boot folding, both of which mainly occur at high joint internal pressures. Line Ø Dg represents the typical grease fill level for such a joint 12.
FIGS. 4-8 depict another prior art constant velocity joint 42 with a boot 44. The joint 42 comprises an inner race 46, an outer race 48, a cage 50 and at least one ball 52 within the cage. This joint 42 uses a sleeve 54 that couples the inner race 46 with a pinion shaft 56. A nut 58 connects the sleeve 54 to the pinion shaft 56.
The sleeve 54 in such a direct pinion mount design has a larger diameter Ds1 than a tube shaft diameter Ds in a non-direct pinion mount design, such as shown in FIGS. 1-3. Therefore, the boot can inner diameter Db1 should increase by the difference between Ds1−Ds to have the equivalent maximum static joint angle capability to that of a non-direct pinion mount design, such as in FIGS. 1-3. This results in a higher grease pressure acting on the direct pinion mount boot 44 compared with the pressure on the boot 10 depicted in FIG. 1.
The boot length L1 is limited by the nut 58 as shown in FIG. 4, therefore, it is more difficult to make the boot length L1 equivalent to the non-direct pinion mount joint boot length L depicted in FIG. 1. This results in a boot can inner diameter Db1 being bigger to have the equivalent boot overall length required for achieving a maximum joint angle compared to the design in FIG. 1.
Further, the limited boot axle length L1 cannot provide a sufficient press fit contact portion 62 between the sleeve 54 and the boot 44, which causes region 64 near a boot groove seat 66 to be bumped up and tilted toward the boot groove seat 66 by a crimping force of a boot clamp 68 acting on the boot clamp seat inside corner 70, which can be appreciated from FIGS. 6 and 7.
FIG. 8 depicts a direct pinion mount joint 42 having uniform boot thickness (T21=T22=T23) that has folded/self-contacted at a boot contacted region 78 as a result of the wrong boot thickness for this design. The figure also depicts the boot 44 being severely bent at an edge of the boot can crimp 80 by high grease pressure while operating at a high temperature, a high operating speed and at a high operating angle.
In view of the disadvantages of attempting to apply a non-direct pinion mount boot system to a direct pinion mount boot system, a new design is required.


A hull locating arrangement for a multi-hulled vessel having a body at least partially suspended above at least a first and a second hull by support components is disclosed. The hull locating arrangement comprises, for a hull, a first locating linkage and a second locating linkage to together constrain the hull in the lateral, longitudinal, roll and yaw directions relative to the body. The first and second locating linkages are longitudinally spaced, and the first locating linkage includes a first part and a second part, one of the parts of the first locating linkage being pivotally connected to the body about a body end pivot axis, and the other of the parts being pivotally connected to the hull about a hull end pivot axis. The first locating linkage is also arranged to permit relative motion between the first and second parts along at least one sliding axis to thereby permit the first locating linkage to vary in length between the body end pivot axis and the hull end pivot axis. The support components include a first support component adjacent the first locating linkage, the first support component including a first support element providing a support force supporting a portion of the body above the first hull. The support force of the first support element has a line of action that is within thirty degrees of parallel to a first linkage plane extending through the body end pivot axis and the hull end pivot axis.

In the applicant's earlier International Patent Application Numbers PCT/AU2011/000557 and PCT/AU2011/000565 there are disclosed various configurations of catamaran, trimaran and quadmaran all having resilient suspension between at least two laterally spaced hulls and central hull or body. Where two longitudinally spaced locating linkages are provided between one hull and the body some form of longitudinal compliance or freedom is required in one of the locating linkages. For example to locate one hull relative to the body, a front fixed length trailing arm is used and a back variable length trailing arm is used. The variable length of the back trailing arm is provided by telescopic or sliding sections in the arm or by a drop link. The support forces are provided by rams which provide a moment on the trailing arms which can require the trailing arms to be of very high strength and large section on some vessels and places a high side load on the sliding joints of the variable length arm which increases the friction of the sliding joints and therefore reduces joint life and ride comfort. Alternatively the rams are provided connected directly between the body and the hull, which can require a large tower on the deck of the body to accommodate the rams which can be difficult to package in some vessel designs and layouts. Also wherever the suspension arms and rams are located in separate areas of the vessel, having separate load paths through respective mounting points into the body and/or the hull(s), the greater the spacing between the respective mounting points, generally the more bending induced into the body and/or hull and the less efficient the design in terms of packaging and weight.

Improvements to multi-hull vessel suspension geometry


A noncrosslinked polyethylene resin expanded particle is provided having a bulk density BD in a range of 10 g/L to 100 g/L, the particle being obtained by expanding a polyethylene resin particle whose density is in a range of 0.920 g/cm3 to 0.940 g/cm3, the noncrosslinked polyethylene resin expanded particle having a shrinkage factor in a range of 2% to 30%, the shrinkage factor being obtained by the following formula (1):Shrinkage Factor=(BD−VBD)×100/VBD  (1),wherein: the BD of the noncrosslinked polyethylene expanded particle is a bulk density at 23° C. and at 0.1 MPa (at a normal atmospheric pressure); and the VBD of the noncrosslinked polyethylene expanded particle is a bulk density at 23° C. and at a reduced pressure of 0.002 MPa or less.

The polyethylene resin expansion molded articles are widely used for buffer packing materials or the like. These polyethylene resin expansion molded articles are produced from polyethylene resin expanded particles.
In a case where a polyethylene resin expansion molded article is produced from polyethylene resin expanded particles, thus obtained expansion molded article has a large dimensional shrinkage factor with respect to a metal mold and a poor dimensional accuracy. This problem tends to emerge noticeably particularly in a case where the polyethylene resin expanded particles are obtained by using inorganic gas as a foaming agent.
In order to solve the above problem, various studies have been made. For example, studies have been carried out on a method in which foaming capability is given by adding various molding gases to expanded particles (Patent Literatures 1 and 2), a method in which foaming capability is provided by compression of expanded particles (Patent Literature 3), a method in which a ratio of an expansion ratio of pre-expanded particles and an expansion ratio of expanded particles used in molding are controlled within a predetermined range (Patent Literature 4), and a method in which a complex temperature history is given after molding (Patent Literatures 5 and 6).
However, each of the above methods has advantages and disadvantages. Further, there are restriction due to equipment and many other problems that need to be solved. For example, in the case where molding gas is added as described in Patent Literatures 1 or 2, equipment for adding gas to expanded particles is required. Further, for preventing deterioration in given foaming capability, such equipment for adding gas and a molding process need to be integrated or arranged to be continuous.
For the method in which expanded particles are compressed as described in Patent Literature 3, equipment for the compression is required. Further, such equipment for the compression needs to be integrated with a molding machine. In addition, in this method, there are problems such that performance in filling the expanded particles is poor and a ratio at which defective products occur is high as compared to a case where the expanded particles are not compressed.
In regard to the method as described in Patent Literature 4 in which a ratio of an expansion ratio of pre-expanded particles and an expansion ratio of expanded particles used in molding is controlled, it is necessary to prepare pre-expanded particles having an expansion ratio that is unnecessarily high. Further, for controlling the ratio of the expansion ratios described above, it is necessary to retain the pre-expanded particles in an atmosphere at a temperature of approximately 60° C. for hours so that the expansion ratio of the pre-expanded particles is adjusted to a desired level.
In regard to the method as described in Patent Literatures 5 and 6 in which a complex temperature history is given after molding, work operations are complicated. Therefore, this method is not advantageous as a production process.
As described above, it has been difficult to easily obtain a noncrosslinked polyethylene resin expanded particles that allows providing, by a simple method, a polyethylene resin expansion molded article whose dimensional shrinkage factor with respect to a metal mold is small, whose deformation is small, and whose surface stretches well.

Method for producing noncrosslinked polyethylene resin expanded particle (first stage expanded particle) and re-expanded noncrosslinked polyethylene resin expanded particle


Methods and compositions which can be used to increase the strength and/or probability of forming a binding complex comprising a target molecule and a substrate are disclosed. In one aspect, linking molecules are disclosed which can be used to increase the number of intra-complex binding interactions. Covalent bonds can be introduced to further increase the strength of these binding interactions. Inter-complex cross-linking can be utilized in connection with these methods to further strengthen and stabilize the disclosed binding complexes.

Magnetic sensing capabilities developed in electronics and semiconductor industries in applications such as the read heads in hard drives have seen great advancements in the last couple decades with higher sensitivity and density. In recent years there has been much interest in applying these capabilities to the detection of biomolecules. The present disclosure addresses these issues, and provides related advantages.

Methods and compositions in particle-based detection of target molecules using linking molecules


A disposable cassette for use with a medical infusion pump. An elastomeric membrane is captured between a facing member and a base of the cassette and is displaced into a pumping chamber. The elastomeric membrane includes a generally T-shaped lip, and corresponding grooves are provided on the facing member and base. As the cassette is assembled, an interference fit between the lip and the grooves causes the membrane to stretch taut and to be securely anchored, eliminating a break-in period when the cassette is initially used. xe2x80x9cLobesxe2x80x9d of increased thickness provided on the undersurface of a portion of the elastomeric membrane overlying the pumping chamber reduce the residual volume of the pumping chamber, thereby reducing the volume of air retained within the chamber and increasing the accuracy of the cassette. The lobes also sweep air bubbles from the sides of the pumping chamber during operation, further reducing air bubbles retained in the pumping chamber. A distal tube support retains a distal fluid line between air or pressure sensors included on a pump drive mechanism, thus reducing the likelihood of sensing errors. Inlet and outlet valve flaps and corresponding seating surfaces included in the base are configured to provide quieter operation, further reduce the residual volume of the pumping chamber, increase fluid velocity through the outlet valve to sweep air bubbles from the pumping chamber, and protect against a xe2x80x9cblownxe2x80x9d inlet valve.

The present invention generally relates to a positive displacement volumetric infusion cassette pump, and more specifically, to a disposable cassette adapted for use with such a pump, the cassette having an elastomeric membrane that is displaced by a plunger into a cavity to pump fluid and including integral inlet and outlet valve components formed on a surface of the elastomeric membrane.
Various types of pumps are used by medical personnel to infuse drugs into a patient""s body. Of these, cassette infusion pumps are often preferred because they provide a more accurately controlled rate and volume of drug infusion than other types of infusion pumps. A cassette pump typically employs a disposable plastic cassette coupled between a proximal liquid line extending from a drug reservoir or source, and a distal fluid line that is coupled to the patient""s body. The cassette is adapted to engage and be driven by a pump mechanism that includes a control and an interface for setting the desired flow rate, volume of fluid, and other parameters that control the infusion process.
In one prior art design of a disposable cassette, the cassette comprises a plastic shell or housing having a facing member joined to a base. The cassette is inserted into an appropriate receptacle in a pump chassis that typically includes a microprocessor controller and a motor or solenoid-actuated driver. A thin elastomeric sheet or membrane is encapsulated between the two sections. Inlet and outlet flapper valves are formed on one side of this elastomeric membrane and seal against adjacent surfaces formed on the base. These flapper valves are actuated in response to fluid pressure and the force applied by a plunger against the elastomeric membrane. As the plunger withdraws following a pumping stroke, the inlet flapper valve opens, enabling liquid to flow from the drug reservoir through an inlet port of the cassette and into a pumping chamber defined in the base and covered by the elastomeric membrane. The plunger actuated by the motor or solenoid in the pump driver displaces the elastomeric membrane into the pumping chamber, opening the outlet flapper valve and forcing liquid under pressure from the pumping chamber, through an outlet port. The pump chassis thus provides the driving force that pumps liquid through the cassette. In addition, the pump chassis normally includes one or more pressure sensors and air bubble sensors for monitoring and controlling the drug infusion process to protect against potential problems that may arise during delivery of a medicinal liquid to a patient.
Cassette infusion pumps have been widely adopted by the medical profession, which uses millions of such disposable cassettes per year. As is common with other high volume production items, manufacturers continually strive to improve their products. For instance, in prototype unit developed by applicant as a replacement for an existing product, it was observed that during operation, the prototype cassette produced a surprising level of audible noise. Much of this undesirable noise can be attributed to the operation of the flapper valves. Also, in prior art cassettes, when exposed to higher than optimal pressure conditions, the flapper valves can be xe2x80x9cblown,xe2x80x9d that is, the flapper valves can be forced beyond their sealing surfaces by excess pressure. It would therefore be desirable to provide a cassette that includes valve elements that produce substantially less audible sound when operating, and are much less susceptible to being xe2x80x9cblown.xe2x80x9d
Improving the reliability of disposable cassettes is also a goal of both end users and manufacturers. As noted above, disposable cassettes frequently are adapted to engage with air or pressure sensors included on the pumping mechanisms used, which can trigger an alarm to alert an operator of an undesirable or unsafe operating condition. The disposable cassettes generally include sensor ports that enable the sensors disposed on the pumping mechanism to monitor a parameter such as pressure or the presence of air in a fluid line. Including the sensor ports within a disposable cassette can increase the size and cost of the cassette. It would be desirable to eliminate any air sensor ports from the disposable cassette, so that the size and cost of disposable cassettes can be substantially reduced. Instead, the air sensors should be positioned to sense parameters relating to the presence of air contained within a tube set that is connected to the outlet port of the cassette. For proper operation, it is important that the positional relationship between the external air sensors and tubing be stable and consistent, because if the tubing moves relative to the sensors, false alarms can be generated, and/or errors in the monitored parameters can result. It would thus be desirable to provide a cassette that incorporates elements, which ensure the fluid tubing remains in a predetermined position relative to external air sensors, to reduce the possibility of erroneous sensor readings and false alarms due to movement of the fluid tubing relative to the sensors.
Another goal in the further development of disposable cassettes is improving the accuracy with which a medicinal liquid is delivered. It is well understood that air bubbles within cassettes are undesirable for several reasons. While gross amounts of air bubbles, such as levels that pose a risk to a patient""s health by causing an embolism, are not much of a risk in such systems, even smaller volumes of air retained within a cassette pumping chamber can adversely impact the accuracy with which medicinal liquid is delivered to a patient. Prior art cassettes typically attempt to prevent air bubbles in the system by using a combination of an integral air trap and appropriate cassette priming procedures. While air traps and proper priming techniques generally avoid the delivery of large volumes of air that can pose a health risk, smaller volumes of air bubbles that become trapped within the cassette are more difficult to remove. When air bubbles are present within the pumping chamber, accuracy is affected in several ways.
The volume of the pumping chamber is a critical parameter in the algorithm controlling the pump to achieve accuracy in delivering a desired volume of medicinal liquid. The presence of air bubbles within the pumping chamber effectively reduces the volume of the pumping chamber, so that less than a desired volume of fluid will be delivered each pump cycle. Increasing the complexity of this problem is that pressure conditions within the pumping chamber vary during the pumping cycle, so that the actual volume of a fixed mass of air within the pumping chamber is not constant. Thus, the actual volume of fluid delivered cannot be accurately determined and compensated, because the volumetric error caused by the mass of air trapped within the pumping chamber is not constant. Accordingly, it would be desirable to provide a disposable cassette including elements that reduce the generation and/or retention of air bubbles within the pumping chamber, and elements that promote the removal of any air bubbles that are present in the pumping chamber.
Another aspect of the accuracy of prior art disposable cassettes relates to the elastomeric membrane. In prior art cassettes, the elastomeric membrane typically requires a break-in period the first time the cassette is used. This break-in period is required to enable the elastomeric membrane to reach an equilibrium, so that the repetitive manipulation of the membrane during successive pumping cycles produces repeatable results. Generally, the break-in period is required to enable the membrane to become seated with respect to the facing member and base of the housing that retain the elastomeric membrane, so that repeated manipulation of the membrane does not result in any further stretching or movement of the membrane relative to the housing.
Clearly, it would be desirable to provide a disposable cassette that reduces operating noise, that provides enhanced protection against valve deformation (failure) under excessive pressure conditions, that substantially reduces false alarms and increases the reliability of external sensor data, that provides increased accuracy by reducing the volume of air trapped in the pumping chamber, and by eliminating the need for a break-in period of the elastomeric membrane. The prior art does not provide such a disposable cassette.
The present invention defines a cassette that is adapted to engage a drive mechanism, for use in infusing a fluid into a patient. The cassette includes a housing having a base on which is mounted a facing member. An elastomeric membrane is secured between the facing member and the base. A fluid path between the elastomeric membrane and the base extends through the cassette between an inlet port and an outlet port. The fluid path includes an inlet passage coupled in fluid communication with the inlet port, an outlet passage coupled in fluid communication with the outlet port, and a pumping chamber disposed between the inlet passage and the outlet passage. When the elastomeric membrane is displaced into the pumping chamber, it is adapted to force a fluid from the pumping chamber. The elastomeric membrane has a substantially T-shaped lip extending around and proximate its peripheral edge. The T-shaped lip is captured in an interference fit within a groove formed in opposed surfaces of the facing member and the base so that the elastomeric membrane is stretched taut as the facing member is joined to the base. The groove includes inclined surfaces that are in interference with corresponding inclined surfaces on the T-shaped lip. When the facing member is seated onto and joined to the base with the lip of the elastomeric membrane captured in the groove, a tension in the elastomeric membrane produced by the interference fit due to an interaction of the inclined surfaces of the groove and the T-shaped lip compensates for any inelastic deformation of the elastomeric membrane occurring when the elastomeric membrane is displaced into the pumping chamber. This compensation thus minimizes errors in achieving a desired volume of a fluid infused by the cassette.
In at least one embodiment, an extent of an area of the elastomeric membrane defined by the inclined surfaces of the T-shaped lip is less than an extent of an area defined in the base and facing member by the inclined surfaces of the groove formed therein. Preferably, the facing member is seated against and ultrasonically welded to the base while the T-shaped lip of the elastomeric membrane is compressed in the interference fit within the groove.
Also, the fluid path preferably further includes an inlet valve disposed between the inlet passage and the pumping chamber, and an outlet valve disposed between the pumping chamber and the outlet passage. The inlet valve includes an inlet valve surface formed in the base, and an inlet valve flap formed on an undersurface of the elastomeric membrane that seats against the inlet valve surface when the inlet valve is closed. Similarly, the outlet valve includes an outlet valve surface formed in the base, and an outlet valve flap formed on the undersurface of the elastomeric membrane that seats against the outlet valve surface when the outlet valve is closed. In at least one embodiment, the inlet valve surface on the base includes a ramp, and the inlet valve flap is substantially thinner at a depending tip thereof than a depending tip of the outlet valve flap. The depending tip of the inlet valve flap is also substantially thinner than a portion of the inlet valve flap where it is joined to the undersurface of the elastomeric membrane. In this manner, the inlet valve and the outlet valve are configured to substantially reduce audible noise produced as the inlet valve and the outlet valve open and close. The thickness of the outlet valve flap and its disposition relative to the outlet valve surface preferably provide a biasing force tending to keep the outlet valve closed until a fluid pressure in the pumping chamber reaches a predetermined level. This biasing force is selected to prevent siphon free flow of a fluid through the cassette.
The base further preferably includes a tube support member that extends beyond the outlet port and is adapted to support a tube that is coupled to the outlet port to receive fluid forced from the cassette. The tube support member ensures that the tube remains statically positioned relative to an air-in-line sensor provided on the drive mechanism during use of the cassette.
Another aspect of the present invention is directed to a method for mounting an elastomeric membrane in a cassette used for infusing a fluid into a patient, so as to pre-load the elastomeric membrane under an outwardly directed tension. The steps of the method include providing a generally T-shaped lip extending around and proximate to a peripheral edge of the elastomeric membrane. The T-shaped lip has inclined surfaces extending from where the T-shaped lip extends from a generally planar surface of the elastomeric membrane toward distal tips of the T-shaped lip. Other steps of the method include providing a base and a facing member for the cassette that each include a groove with inclined surfaces shaped and sized to receive a different distal tip of the T-shaped lip in an interference fit.
The steps of the method further include positioning a distal tip of the T-shaped lip of the elastomeric membrane in the groove formed in one of the base and the facing member, then seating the groove formed in the other of the base and the facing member onto an opposite distal tip of the T-shaped lip, and pressing the base and the facing member toward each other until the T-shaped lip seats within the grooves formed in the base and the facing member. The interference fit between the inclined surfaces of the grooves and the T-shaped lip draws the elastomeric membrane taut under a pre-load tension. The next step involves joining the base and the facing members together while the elastomeric membrane is taut, so that the elastomeric membrane is captured under the pre-load tension between the facing member and the base.
Preferably, the step of joining the base and the facing members involves ultrasonically bonding the facing member to the base, or alternatively, the base and facing member are joined using thermal bonding or adhesive bonding. Also, the step of providing the T-shaped lip preferably includes the step of molding the lip around a peripheral edge of the elastomeric membrane. An area of the elastomeric membrane within the lip is less than an area circumscribed by the grooves formed in both the base and the facing member.
Another aspect of the present invention is directed to a cassette that includes an elastomeric membrane having lobes adapted to sweep air bubbles from the sides of the pumping chamber, thereby minimizing errors introduced by air bubbles disposed within the pumping chamber. As before, the cassette is adapted to engage a drive mechanism and is used for infusing a medicinal liquid into a patient. Also as noted above, the cassette includes a housing having a base on which is mounted a facing member. A fluid path is defined between the elastomeric membrane and the base, and extends through the cassette between an inlet port and an outlet port. The facing member is employed to secure the elastomeric membrane relative to the base, and the facing member is preferably not part of the fluid path. The fluid path includes an inlet passage coupled in fluid communication with the inlet port, an outlet passage coupled in fluid communication with the outlet port, and a pumping chamber disposed between the inlet passage and the outlet passage. When the elastomeric membrane is displaced into the pumping chamber, it forces a fluid from the pumping chamber. The elastomeric membrane has a generally planar undersurface facing toward the base, but this surface includes two lobes of increased thickness disposed above the pumping chamber, at opposite sides thereof. The increased thickness of the lobes extends into the pumping chamber so that when the elastomeric diaphragm is displaced into the pumping chamber by a drive mechanism, the lobes sweep away many air bubbles that may be retained on adjacent walls of the pumping chamber. When displaced into the pumping chamber, the lobes also preferably define a shallow elongate path through the pumping chamber between the lobes, so that a substantial portion of any air contained within the pumping chamber is carried out of the pumping chamber with the medicinal liquid being infused.
Preferably the elastomeric membrane further includes an inlet valve flap and an outlet valve flap, both of which depend from the undersurface of the elastomeric membrane. The inlet valve flap, when closed by a fluid pressure within the pumping chamber, forms a seal against an inlet valve surface formed in the base and disposed between the inlet passage and the pumping chamber. In similar fashion, the outlet valve flap when closed, forms a seal against an outlet valve surface defined in the base and disposed between the pumping chamber and the outlet passage. The inlet valve is preferably configured to be substantially thinner at a tip than where the inlet valve flap joins with a substantially planar portion of the elastomeric membrane and comprises a ramp that is inclined at an angle. The angle is selected so that in cooperation with the inlet valve flap, audible noise caused by repetitive opening and closing of the inlet valve flap relative to the inlet valve surface is substantially reduced. The outlet valve flap is preferably substantially thicker than the inlet valve flap and provides a biasing force tending to maintain the outlet valve flap sealed against the outlet valve surface until a pressure in the pump chamber exceeds a predefined level. Preferably, the predefined level is selected to prevent a siphon induced free flow of fluid through the cassette.
The base of the cassette includes a distal member that extends distally past the outlet port and is adapted to support a tube that is coupled in fluid communication with the outlet port. The support of this distal member minimizes movement of the tube relative to an air-in-line sensor that is included in the drive mechanism.

Disposable infusion cassette with low air bubble retention and improved valves


A transmitter identification code is designed such that the code varies as the code is assigned. In one embodiment the code will include information with regard to the date and time that the code is initially determined. In a second embodiment the code is provided by incrementing a counter, and then modifying that counter information such that the final code is non-sequential.

This application relates to the provision of a transmission identification code to a remote entry transmitter wherein the code is assigned in a fashion such that it will always be unique, and such that the transmission identification codes for any two consecutive transmitters will not be consecutive binary numbers.
Remote entry transmitters are utilized in most modem vehicles. In a remote entry transmitter a signal is sent from a small signaling device, typically known as a keyfob, to the vehicle. The vehicle receives the signal and controls components on the vehicle based on the signal. As an example, remote entry transmitters are typically utilized to lock and unlock the doors on the vehicle.
When the signal is initially sent from the transmitter to the vehicle, the vehicle checks the signal to determine whether the transmitter is an appropriate transmitter for the vehicle. Transmitters typically have a unique code which is distinct from other transmitters. In this way, the control on the vehicle can identify whether the particular transmitter sending the particular signal is a transmitter which has been programmed for the vehicle. Typically the programming occurs at the factory, when the vehicle is initially assembled and associated with a particular transmitter. Under some circumstances a transmitter may be programmed to a vehicle later, such as when a keyfob has been lost, etc.
Some vehicle manufacturers have a goal of ensuring that no two transmitter identification codes will be identical. This has a resulted in a requirement for storing all of the previously used codes such that it can be ensured that no future identical code is utilized.
It would be desirable to provide a simplified way of assigning transmission identification codes to remote entry transmitters that eliminate the need to store all prior codes.

Remote entry transmitter with transmission identification codes


A speech model preparing method capable of easily preparing a new Hidden Markov Model (HMM) of an input speech with a very few number of utterances like one or two times, and a speech recognition apparatus using this method. A speech recognition apparatus uses, as a speech model, a continuous distribution type HMM defined by three parameters of a state transition probability, an average vector and a variance. The apparatus computes an average vector of an input speech to be learned, selects an HMM approximate to the input to-be-learned speech as an initial model from a registration dictionary, replaces at least an average vector of the selected HMM with the computed average vector of the to-be-learned speech and adds an obtained HMM as an HMM for the input to-be-learned speech in the dictionary.

1. Field of the Invention
The present invention relates to a method of preparing a speech model using a continuous distribution type HMM (Hidden Markov Model) and a speech recognition apparatus using this method. More particularly, this invention relates to a speech model preparing method capable of preparing the HMM of a new input speech with a very few number of utterances like one or two times, and a speech recognition apparatus using this method.
2. Description of Background Information
There is a probability-model based speech recognition apparatus which uses an HMM. This HMM is a Markov model which has a plurality of statuses linked with a state transition probability and is characterized by outputting a predetermined symbol in accordance with a symbol output probability when the status changes from one state to another. Generally, speech recognition uses a left-to-right model which does not involve reverse time sequence.
This speech recognition apparatus using such an HMM is designed to prepare HMMs for all the words to be recognized and register them in a dictionary in advance. At the time of speech recognition, the speech recognition apparatus sequentially reads HMMs from the dictionary, computes the probability (likelihood) of outputting the same observing symbol series as the input speech for each HMM, and outputs a word corresponding to the HMM which gives the highest probability, as the recognition result.
FIG. 1 exemplifies an HMM, which can output two symbols a and b and has three internal statuses S.sub.1 to S.sub.3. The status starts from S.sub.1 and ends at S.sub.3. The lines with arrowheads connecting the individual statuses S.sub.1 -S.sub.3 represent the state transitions, and a.sub.ij along each arrow line indicates the state transition probability while c.sub.ij indicates the symbol output probability then. The upper element in the parentheses "!" in the symbol output probability c.sub.ij is the output probability of the symbol a, and the lower element is the output probability of the symbol b.
Given that the observing symbol series of the input speech is (aab), the probability (likelihood) that the HMM in FIG. 1 outputs this observing symbol series (aab) is computed as follows (see "Markov Model Based Voice Recognition", by Masaaki Okouchi, Journal of Electronic Information Communication Society of Japan, April 1987, for example).
The syllables in the observing symbol series (aab) have three lengths /a/a/b/, so that the change or transition paths which allow the observing symbol series (aab) to be output for the HMM in FIG. 1 are limited to three routes: S.sub.1 .fwdarw.S.sub.1 .fwdarw.S.sub.2 .fwdarw.S.sub.3, S.sub.1 .fwdarw.S.sub.2 .fwdarw.S.sub.2 .fwdarw.S.sub.3, and S.sub.1 .fwdarw.S.sub.1 .fwdarw.S.sub.1 .fwdarw.S.sub.3.
Because the probability that the observing symbol series (aab) is output for each transition path is expressed by all the products of the state transition probability a.sub.ij and the symbol output probability c.sub.ij along that transition path, the probabilities for the three transition paths take the following values.
For S.sub.1 .fwdarw.S.sub.2 .fwdarw.S.sub.2 .fwdarw.S.sub.3, EQU 0.3.times.0.8.times.0.5.times.1.0.times.0.6.times.0.6=0.036
For S.sub.1 .fwdarw.S.sub.2 .fwdarw.S.sub.2 .fwdarw.S.sub.3, EQU 0.5.times.1.0.times.0.4.times.0.3.times.0.6.times.0.5=0.018
For S.sub.1 .fwdarw.S.sub.1 .fwdarw.S.sub.1 .fwdarw.S.sub.3, EQU 0.3.times.0.8.times.0.3.times.0.8.times.0.2.times.1.0=0.01152
Since any of the three transition paths can output the observing symbol series (aab), the sum of those three probabilities, 0.036+0.018+0.01152=0.06552, becomes the probability (likelihood) of outputting the observing symbol series (aab) for the HMM in FIG. 1. For simplicity, the maximum value, "0.036", in the computed three probabilities may be treated as the probability for that HMM.
The input speech can be recognized by performing this probability computation for all the HMMs registered in the dictionary and outputting a word corresponding to the HMM that gives the highest value in the computed probabilities as the recognition result.
As shown in FIGS. 2A and 2B, there are a discrete distribution type HMM for which the symbol output probability c.sub.ij changes discontinuously and a continuous distribution type HMM for which the symbol output probability c.sub.ij changes continuously. Because discrete distribution type HMMs are accompanied with a quantization error, continuous distribution type HMMs are frequently used in speech recognition.
It is apparent from FIG. 2B that the symbol output probability c.sub.ij for the continuous distribution type is defined by the average vector .mu. and a variance .SIGMA. of a symbol. Therefore, a continuous distribution type HMM is entirely described by three parameters: the state transition probability a.sub.ij (see FIG. 1), the average vector .mu. and the variance .SIGMA..
To prepare an HMM for each registered word, learning should be performed using many samples in a population representing a speech model to predict the associated three parameters. As the method for this prediction, there are known several algorithms which include forward and backward algorithms.
With regard to the computation of the probability that an HMM exemplified in FIG. 1 outputs the observing symbol series (aab), there are likewise known several algorithms which include the forward algorithm and Viterbi algorithm.
As the HMM-based speech recognition apparatus executes speech recognition using the above-discussed probability scheme, it is excellent as a speech recognition apparatus for unspecific speakers and is being adapted in various fields, such as a voice command system in a vehicular navigation apparatus.
However, the current HMM-based speech recognition apparatus is not yet complete and causes a recognition error or recognition failure when words not registered in the dictionary are input or when uttered words, even if registered in the dictionary, are very different from standard patterns.
When a recognition error or recognition failure occurs, it is necessary to prepare a new HMM for that input speech and add it in the dictionary in order to enable the recognition of that input speech next time. According to the conventional learning method, however, a single word should be uttered ten to twenty times to predict the three parameters, namely the state transition probability, average vector and variance, and prepare a new HMM for the input speech. This method requires a great deal of efforts and time to register each additional word.
If the registration of additional words takes a lot of efforts and time, it is difficult to learn while an automobile or the like are running so that the vehicle should be stopped every time additional registration is needed. When a user is in a hurry, additional registration is carried out long after, so that the user may forget the input speech (word) to be additionally registered or may even forget the task of adding the word itself.

Method of preparing speech model and speech recognition apparatus using this method


Provided are systems and methods for long-range, high-resolution, laser radar range detection. In one embodiment such a system includes an optical pulse modifier configured generated a stretched optical pulse and an optical amplifier configured to increase an optical power of the stretched optical pulse The system can further include an optical spectrum analyzer configured to determine a wavelength of a spectral peak that results from interference between a first amplified stretched pulse that is reflected from a target and a second amplified stretched pulse that is spectrally reversed.

A combination of radar and optics provides a system with inherently enhanced accuracy in the measurement of range, velocity and angular displacement, and improved countermeasure resistance. For example, laser radar is simply radar transformed from measuring reflected radio frequency electromagnetic radiation to locate spatially removed objects, to a system that operates on laser radiation. The high carrier frequency allows laser radar systems to be made more compact in physical dimension, which is particularly attractive in aircraft, projectile, space, and other volume-limited applications.
Disadvantageously, the penetrating ability of optical radiation is severely degraded by, for example, weather-related atmosphere disturbances. Consequently, the major developments in laser radar technology have been directed at range-finding capabilities, particularly as fire control for mobile and air defense weapon systems. Laser radar technology can also be used as a proximity fuzing device.
Laser radar systems typically use the time of travel of a reflected signal to calculate a range value. For example, briefly referring to FIG. 1, a laser radar system 100 transmits a pulse 102 to a target 106. The transmitted pulse 102 reflects from the target 106 in the form of a reflected pulse 104. The laser radar system 100 receives the reflected pulse 104 and determines the distance to the target based on the time of travel of the laser pulse. The resolution of the time of travel calculation, however, is limited to the length of the laser pulse utilized by the system. For at least this reason, short pulse lasers are ideally used to increase resolution. Additionally, measurement over long distances requires laser pulses to have high total energy levels for reliable reflected laser detection. The short pulses, however, are difficult to amplify to an energy level sufficient to achieve desirable long range performance. Longer pulses that are capable of containing sufficient energy, however, reduce the resolution to an undesirable level. Thus, a need exists in the industry to provide high-resolution long-range laser radar range detection.

Systems and methods for long-range, high-resolution laser radar range detection

University of Central Florida Research Foundation


A communication method particularly suited for lighting control employs encoding of perturbations in a voltage signal having a fundamental period with a nominal waveform. A control period includes a pre-selected number of fundamental periods of the voltage signal. Different control commands are indicated by imposing a selected perturbation, such as a phase cut, on the nominal waveform with a respective occurrence signature within the control period. The control commands are decoded from the voltage signal by detecting the occurrence signature of the perturbations within each control period. Decoding is accomplished by differentiating the nominal waveform to detect encoded perturbations. The technique is particularly suited for two-wire dimming applications for gas discharge lamps, in which the voltage signal carrying the encoded commands is the sinusoidal mains voltage powering the ballast, since the encoded perturbations may be small enough so that lamp flicker is avoided even with encoded signals on the line voltage. In a favorable embodiment for dimming, no perturbations are introduced on the line voltage unless a change in the operating characteristic, for example the light level, of the electric lamp is desired. This has the advantage that when lamp operation is to be kept constant, no distortions are imposed on the mains voltage, so that flicker of the lamp(s) is completely avoided and there are no adverse effects to the power factor, THD or component stress.

1. Field of the Invention
The invention generally concerns an improved technique for communicating control information to control the operation of an electric lamp, such as for dimming. The invention also relates to a wall controller and a ballast implementing the improved communication method.
2. Description of the Prior Art
Electronic dimming ballasts are commercially available in which dimming of gas discharge lamps, typically fluorescent lamps, is responsive to phase angle control of the AC power line input. Phase angle control involves the clipping of a portion of each half cycle of the AC sinusoidal power line voltage. A common type of phase angle controller, known generally as a forward phase dimmer, clips or blocks a portion of each half cycle immediately after the zero crossing. An example of a forward phase dimmer is the well known triac dimmer. Another type is the reverse phase dimmer, commonly known as an electronic dimmer, which passes the portion of the half-cycle immediately after the zero crossing and blocks the portion of the half cycle before the zero-crossing. In both types, the portion or angle of the half cycle which is blocked is adjustable.
Phase angle dimming in which the phase angle information is supplied by an additional wire separate from the power line inputs powering the ballast are known, for example, from JP-116698, U.S. 4,797,599, and DGM 9014982. Such ballasts are inconvenient in that their installation requires the running of the additional, dim-signal-carrying wire between the controller, which is typically mounted in a wall, and the ballast mounted in the fluorescent lamp fixture in the ceiling. This results in considerable labor costs and is an impediment to market acceptance.
Lamp ballasts are also known which are two-wire devices in which the phase cut signal is not separate from the mains supply but is carried by the hot power line input. These are more attractive, from an installation standpoint, than the threewire devices and are known inter alia from U.S. Pat. No. 4,392,086 (Ide et al), U.S. Pat. No. 5,192,896 (Qin), U.S. Pat. No. 4,866,350 (Counts), U.S. Pat. Nos. 4,449,897 (Sairanen), and 5,101,142 (Chatfield).
A disadvantage of each of the above two-wire ballasts is that they each employ voltage control dimming, i.e. the light output of the lamps is effected through variation in the average line voltage, through control of the conduction angle by the triac or electronic dimmer, which in turn changes the ballast bus voltage feeding the ballast's inverter. The dimming level is inversely proportional to the phase angle blocked or cut from the mains voltage. No phase cut corresponds to a maximum light level while increased dimming (lower light level) corresponds to more phase cut. One adverse consequence is that in order to maintain the light level below 100%, the power line voltage must be maintained in a modified state, i.e. with every cycle having a phase cut portion. This adversely effects the performance of the ballast in several ways. First, it lowers the power factor of the ballast during dimming. Secondly, it increases total harmonic distortion (THD). Third, it increases stress on the circuit components. Fourth, it increases EMI, making it more difficult to meet known standards, especially for consumer use.
Another disadvantage is lamp flicker. When the input conduction angle of the line voltage from the phase angle dimmer falls below a certain value, the preconditioner may not be able to draw enough power to maintain the bus voltage at the required level while supplying power to the lamp driver circuitry. If the ballast is left to operate in this mode, the lamp cycles on and off, resulting in severe flicker. Still another disadvantage is limited dimming range. For example, in U.S. Pat. No. 5,101,142 the effective dimming range is limited to conduction angles less than 90 because at higher angles the output voltage of the preconditioner stays the same. The dimming range is limited at the low end to conduction angles at which the resulting bus voltage is high enough to maintain the compliance voltage sufficiently high so that the lamps don't extinguish. Yet another deficiency is the quality of light regulation. In response to a triac dimming input, the ballast of U.S. Pat. No. 5,101,142 provides a dimming control signal, which varies inverter switching frequency, derived from a bus voltage which varies with the input conduction angle. Thus, lamp light output is effected by two varying parameters, the bus voltage and the inverter switching frequency, which inhibits the accuracy of the dimming control.
U.S. Pat. No. 5,068,576 discloses a step dimmer arrangement in which the wall controller completely cuts or reduces the magnitude of an entire half-cycle, so that there is a missing pulse or a pulse of significantly reduced voltage in the rectified DC output of the ballast's rectifier. The time period between successive missing pulses represents a dimming command. For example, time "n" between missing pulses may represent a 70% dim level while time "m" between missing pulses represents a 90% dim level. In the disclosed ballast, the decoder controls the preconditioner circuit to control the DC rail voltage to the inverter, and thereby control the light level of the lamps. A missing pulse will cause a lamp operated by the ballast to flicker. In the disclosed step-dimming ballast, the flicker is not so objectionable as the user expects a significant and abrupt change in the light output of the lamp when switching from one light level, e.g. 90% to the next, e.g. 75%.
However, where a continuous dimming effect is desired, i.e. where the light should be smoothly adjustable in very small increments, the cutting of entire pulses from the mains supply (and the resulting flicker) would be objectionable to the user.
Accordingly, it is an object of the invention to provide an improved communication method especially suited for lighting control which overcomes the above-mentioned disadvantages of the known techniques. It is another object to provide a wall controller and ballast implementing the improved method.

Coded communication system and method for controlling an electric lamp

Philips Electronics North America Corporation