An optical transmission system comprises a number of optical terminals connected by optical waveguides such as optical fibers. Nonlinear processes occurring within an optical transmission medium of the waveguide or within the optical terminals is detected by a monitor which outputs monitored data representative of the products of nonlinearity. The data is used to control the power of the optical signal such that power is regulated to avoid the onset of the nonlinear process. The data may also be used to indicate an alarm condition to an operator. A monitor for four wave mixing detection utilizes dither signals applied to respective frequency components of a wavelength division multiplexed signal, products of the four wave mixing process being detected in the monitor by correlation between a sample of a received optical signal and reference data representative of dither induced modulation in the four wave mixing product. Mutually orthogonal dither wave forms are derived from pseudo-random sequences and applied as low frequency modulations to transmitted optical signals. Such monitors allow optical power to be controlled and assist in locating defective equipment requiring remedial action. The invention has application to long haul optical transmission systems.

This invention relates to methods and apparatus for transmitting optical signals in an optical transmission system with optimum power while avoiding degradation of the optical signal due to nonlinear processes occurring in an optical transmission medium constituting a component of the optical transmission system.
It is generally desirable in optical transmission systems for optical signals to be transmitted via optical waveguides of the system at high power levels in order to maintain sufficient signal to noise ratios over extended transmission distances such that an acceptably low level of bit error rate is present in the received optical signal. Optical waveguides such as optical fibres however comprise an optical transmission medium which exhibits nonlinear effects at high power levels, resulting in degradation of the optical signal. Nonlinear effects may similarly occur within optical terminals of the system in optical transmission media of components such as optical amplifiers. The optimum power level at which optical signals could be transmitted is typically the maximum power level at which significant degradation due to nonlinearity is avoided. Since the performance of various optical components within the system having respective optical transmission media will vary with operating conditions and age or component replacement, a safety margin is allowed in setting the maximum power level when designating the system. Consequently, it is typically the case that optical transmission systems will operate at power levels which are less than the optimum power level.
A further problem is that an individual optical component forming part of the optical transmission system may suffer a sudden or gradual loss of performance but without total failure such that unacceptable degradation of system performance characterised by the presence of the products of a nonlinear process occurs. Often it may then be difficult to locate the faulty component.
Of particular concern in considering nonlinear processes are the effects of four wave mixing, particularly in relation to WDM (wavelength division multiplexed) optical transmission systems having a number of frequency channels separated by a substantially uniform frequency channel spacing such that each frequency channel may potentially become corrupted with the product of four wave mixing associated with respective pairs of other frequency channels.
In the example shown in FIG. 2(a), four channels having frequencies xcfx891, xcfx892, xcfx893 and xcfx894 are transmitted with equal power.
Considering photon interactions between the xcfx892 and xcfx893 channels only, the four wave mixing process may take the form
xcfx891=2xcfx892xe2x88x92xcfx893=xcfx892xcex94xcfx89xe2x80x83xe2x80x83Equation 1;
or
xcfx894=2xcfx893xe2x88x92xcfx892=xcfx893+xcex94xcfx89xe2x80x83xe2x80x83Equation 2;
where xcex94xcfx89 is the frequency separation between channels.
The products of four wave mixing between photons in channels xcfx892 and xcfx893 therefore occur at frequencies xcfx891 and xcfx894 as illustrated in FIG. 2(b), resulting in a loss of power from the channels xcfx892 and xcfx893 and interference in the wavelength bands around xcfx891 and xcfx894.
For an analysis of nonlinear processes the reader is referred to xe2x80x9cNonlinear Fiber Opticsxe2x80x9d, Second Edition, Govind P. Agrawal, 1995 and in particular to Chapter 10 which deals with four-wave mixing. Problems associated with four-wave mixing are discussed in U.S. Pat. No. 5,410,624 which proposes using dissimilar wavelength channel spacings to avoid interference. The onset of nonlinearity with increasing levels of optical power is discussed in U.S. Pat. No. 5,420,868 which proposes amplitude and phase modulation of components of an optical beam to suppress Stimulated Brillouin Scattering. The cumulative effect of all degradations in a system can be determined by eye measurements as described in U.S. Pat. No. 4,823,360. The individual sources of degradation cannot however by distinguished.
It is known from U.S. Pat. No. 5,512,029 to modulate the optical signals such that each single wavelength channel is modulated with a high speed data stream and a respective low speed, small amplitude dither signal. The dither signals are mutually orthogonal pseudo-random sequences which can be reliably identified by digital correlation techniques in a performance monitoring apparatus. By monitoring a received optical signal, the performance of components of an optical transmission system in terms of the effects of random noise processes is measured by comparing the modulation depth in the decoded dither signal with the known modulation depth of the transmitted dither signal. Defects in components of the system may thereby be detected by observing changes in signal to noise measurements obtained by monitoring the dither modulation depth.
This technique however does not provide any specific sensitivity to the products of nonlinear processes. Furthermore, none of the above references provide a satisfactory technique for monitoring and controlling nonlinear processes within an optical transmission system.
It is an object of the present invention to provide apparatus and method for monitoring optical signals in an optical transmission system to detect degradation of the optical signal due to nonlinear processes.
It is a further object of the present invention to provide a method of controlling the optical power of an optical signal so as to avoid the onset of nonlinear processes.
According to the present invention there is disclosed an optical transmission system comprising;
a plurality of optical terminals;
optical waveguide means interconnecting the optical terminals and operable to conduct optical signals therebetween; and
at least one of the waveguide means and the optical terminals comprising an optical transmission medium susceptible to a nonlinear process at high power levels of the optical signal;
wherein at least one optical terminal comprises monitoring means operable to monitor degradation of the optical signals consistent with the nonlinear process occurring in the optical transmission medium and to output monitored data representative of such degradation.
In the context of the present invention, the term optical terminal is to be understood to include transmitters, receivers, repeaters or other processing elements to which the waveguide means are connected, and in particular including elements of the system which comprise optical amplifiers.
Preferably the optical terminal comprises an alarm indicating means responsive to the monitored data and operable to provide an alarm indication indicative of such degradation being detected.
It is thereby possible to provide the system with one or more alarms which will alert an operator to the need to undertake investigative or remedial action, possibly be replacing a component containing the optical transmission medium upstream of the monitoring means.
The alarm indicating means may provide a remote or local alarm.
The monitored data may also be input to a control means operable to control the power level of the optical signal. When nonlinear processes are detected, the power level may be reduced until the monitored data no longer indicates the presence of products of the nonlinear process. The integrity of the transmitted data may therefore be maintained, subject to the effects of operating at a reduced power level.
Preferably the monitoring means is operable to detect products of four wave mixing. Where the optical signals are wavelength division multiplexed with a plurality of single frequency channels separated by a substantially uniform frequency channel spacing, the monitoring means may be operable to detect products of four wave mixing in at least one of the single frequency channels.
Since prevailing data transmission standards typically require substantially uniform frequency channel spacing, a particular problem is that the products of four wave mixing cause interference and cross-talk in adjacent frequency channels. The monitoring of such processes to provide an alarm or power control feedback therefore provides significant advantages in preserving the integrity of the transmitted data and channel separation.
According to a preferred embodiment, an optical transmission system comprises signal modulating means operable to modulate the single frequency channels with respective high speed data streams and dither modulation means operable to modulate the single frequency channels with respective low speed, small amplitude dither signals.
An advantage of such dither modulation is to provide each of the transmitted frequency channels with a marker which can be identified by a correlation process in the received optical signals in the event of there being cross-talk or cross-channel interference resulting from four wave mixing.
Preferably the monitoring means comprises sampling means operable to detect an optical signal sample of the optical signal after having been transmitted through the optical transmission medium and further comprising a processor operable to perform a correlation between the optical signal sample and reference data representative of dither induced modulation in the four wave mixing product to obtain a correlation value constituting said monitored data.
Preferably the reference data comprises at least one spectral template derived from a predetermined pseudo-random sequence encoded in a respective dither signal.
According to a further aspect of the present invention there is disclosed a method of controlling the optical power of an optical signal in an optical transmission system; the method comprising the steps of;
conducting an optical signal in an optical transmission medium susceptible to a nonlinear process at high power levels of the optical signal;
determining the optical power of the optical signal by action of a variable gain device;
monitoring the optical signal by operation of a monitoring means so as to detect degradation of the optical signal consistent with a nonlinear process occurring in the optical transmission medium;
outputting monitored data from the monitoring means representative of such degradation; and
controlling the variable gain device by operation of a control means responsive to the monitored data such that the level of degradation as indicated by the monitored data remains within a predetermined limit.
According to a further aspect of the present invention there is disclosed monitoring apparatus for use in an optical transmission system comprising sampling means operable to sample a received optical signal to provide sampled data, a processor operable to correlate the sample data with reference data representative of a product of a four wave mixing process being present in the received optical signal; and means for outputting monitored data representative of the detection of products of the four wave mixing process.


A method for setting a reference potential of a current sensor in a power semiconductor device is disclosed. On the basis of a specific geometry and a typical two-dimensional potential distribution of the power semiconductor device, a plurality of tapping points is predetermined on an area of the power semiconductor device. On the basis of the specific geometry of the power semiconductor device, a line course between the tapping points and a measuring point for measuring a potential average value is determined and realized. Respective potential values are detected at the tapping points and fed to the measuring point. The potential average value is determined at the measuring point. The potential of the current sensor is set to the potential average value thus determined.

In power electronics, efforts have increasingly been made for a relatively long time to protect the integrated circuits used against overloading and to initiate suitable measures in the case of electrical or thermal overload. For this purpose, the current flow through a corresponding circuit, in particular a power semiconductor device, and/or the temperature thereof is usually detected and compared with predetermined limit values.
Thus, for realizing self-protecting MOS power semiconductor devices, it is known to provide a current sensor and a temperature sensor on the chip. In an embodiment which is likewise known and often put into practice, the current sensor is embodied as a small DMOS transistor that supplies a current proportional to the load current in the power switching device if the voltage values applied to it are the same as those applied to a load DMOS transistor. This small transistor, which is also referred to as a sense DMOS, has an area which is smaller than that of the load DMOS by a factor of 1,000 to 100,000. A current flows through it which is smaller, ideally by the geometrical ratio of the active areas, than the current flowing through the load DMOS and is therefore a measure of the latter current.
In the form of realization of a common-drain technology, the same drain potential and the same gate potential are present at both transistors. The source potential is tapped off suitably at the load DMOS, and the source potential of the sense DMOS is set to the same potential value. The current that flows in this state is then measured. The current serves as an indicator of the load current presently flowing through the load DMOS.
Conventionally, the source potential at the load DMOS is tapped off in various ways.
Thus, it is known to provide a metal tapping at a measuring point at the chip edge.

Method for setting a reference potential of a current sensor and arrangement for determining the reference potential of a power semiconductor device


The present invention relates to circuit for measuring battery voltage and method for battery voltage measurement using the same. In the circuit for measuring battery voltage and method for battery voltage measurement using the same, three or more capacitors, which form a closed loop and are sequentially connected, are provided, and voltages of voltage sources are measured by using the three or more capacitors in turn, which prevents measurement errors from occurring due to residual charges in the capacitors and enables more precise measurement. Further, according to the present invention, since the three or more capacitors are alternately charged and discharged, the delay in time is decreased, and the voltages of the plurality of voltage sources can be measured at one time. Therefore, it is possible to reduce the amount of time required to measure battery voltage.

Generally, a battery includes a plurality of voltage sources that are connected in series to one another, and voltage of the battery is calculated by measuring voltages from the plurality of voltage sources that are connected in series to one another and summing the measured voltages. Accordingly, the circuit for measuring battery voltage according to the related art that measures a battery voltage includes circuits for measuring the voltages from the plurality of voltage sources, respectively.
FIG. 1 is a circuit diagram illustrating the circuit for measuring battery voltage according to the related art.
Referring to FIG. 1, the circuit for measuring battery voltage according to the related art includes first to 2n voltage sources V1 to V2n (where n is a natural number of 1 or more) that are connected in series to one another, and a first switching bank 1 that has input terminals connected to odd-numbered voltage sources V1 to V2n−1 among the first to 2n voltage sources V1 to V2n.
The circuit for measuring battery voltage according to the related art further includes a second switching bank 2 that has input terminals connected to even-numbered voltage sources V2 to V2n among the first to 2n voltage sources V1 to V2n, a capacitor 3 that has one terminal connected to an output terminal of the first switching bank 1 and the other terminal connected to an output terminal of the second switching bank 2, a voltage measuring unit 5 that measures a voltage charged into the capacitor 3, and a sampling switching unit 4 that connects the capacitor 3 and the voltage measuring unit 5.
The first switching bank 1 includes the odd-numbered switching elements S1 to S2n+1, and the second switching bank 2 includes the even-numbered switching elements S2 to S2n.
The sampling switching unit 4 includes a first sampling switching element 4a that connects one terminal of the capacitor 3 and the positive voltage input terminal (+) of the voltage measuring unit 5, a second sampling switching element 4b that connects one terminal of the capacitor 3 and the negative voltage input terminal (−) of the voltage measuring unit 5, a third sampling switching element 4c that connects the other terminal of the capacitor 3 and the positive voltage input terminal (+) of the voltage measuring unit 5, and a fourth sampling switching element 4d that connects the other terminal of the capacitor 3 and the negative voltage input terminal (−) of the voltage measuring unit 5.
A method of measuring a battery voltage using the circuit for measuring battery voltage according to the related art will be described in detail below with reference to FIG. 2.
According to the method of measuring battery voltage according to the related art, first, a first switching element S1 of the first switching bank 1 and a second switching element S2 of the second switching bank 2 are turned on so as to charge the voltage of the first voltage source V1 into the capacitor 3.
Then, the first sampling switching element 4a and the fourth sampling switching element 4d are turned on, and the voltage of the first voltage source V1 is measured by the voltage measuring unit 5.
Then, the first switching element S1 of the first switching bank 1 and the second switching element S2 of the second switching bank 2 are turned off so as to discharge the voltage of the first voltage source V1 charged into the capacitor 3.
Then, the second switching element S2 of the second switching bank 2 and a third switching element S3 of the first switching bank 1 are turned on so as to charge the voltage of the second voltage source V2 into the capacitor 3.
Then, the second sampling switching element 4b and the third sampling switching element 4c are turned on, and the voltage of the second voltage source V2 is measured by the voltage measuring unit 5.
Then, the second switching element S2 of the second switching bank 2 and the third switching element S3 of the first switching bank 1 are turned off so as to discharge the voltage of the second voltage source V2 charged into the capacitor 3.
According to the method of measuring battery voltage according to the related art, after the voltages of the first to 2n voltage sources V1 to V2n are sequentially measured by repeating the above-described method, the sequentially measured voltages of the first to 2n voltage sources V1 to V2n are summed so as to calculate a total voltage that is charged into the battery.

Circuit for measuring battery voltage and method for battery voltage measurement using the same


Input pipeline registers are provided at inputs to functional units and data paths in a adaptive computing machine. Input pipeline registers are used to hold last-accessed values and to immediately place commonly needed constant values, such as a zero or one, onto inputs and data lines. This approach can reduce the time to obtain data values and conserve power by avoiding slower and more complex memory or storage accesses. Another embodiment of the invention allows data values to be obtained earlier during pipelined execution of instructions. For example, in a three stage fetch-decode-execute type of reduced instruction set computer (RISC), a data value can be ready from a prior instruction at the decode or execute stage of a subsequent instruction.

This invention is related in general to digital processing architectures and more specifically to the use of pipeline registers to facilitate improved processing performance.
A basic design for digital signal processor (DSP) 10 architecture is shown in the prior art diagram of FIG. 1A. DSP calculations require many iterations of fast multiply-accumulate and other repetitive operations. Typically, "functional units" such as multipliers, adders, accumulators, shifters, etc. are used to perform the operations. Such functional units are shown as 12, 14 and 16. The functional units obtain instructions and data, such as values, opcodes, operands, etc. (collectively referred to as "data") from main memory 20 that is typically a random access memory (RAM). The DSP system can be included within a chip that resides in a device such as a consumer electronic device, computer, etc. Note that many variations on the design of FIG. 1A are possible. For example, a single functional unit, such as a general-purpose central processing unit (CPU) can be used. Typically, more than one memory storage unit is used, such as separate storage for instructions and data.
In the basic design, the functional units are constantly transferring data to and from memory, other functional units; and other devices, sources and destinations (collectively referred to as "components"). The speed at which data can be transferred among various components in the architecture design is a primary factor in determining the speed and efficiency of the overall design.
Since accesses to main memory (or external cache or other storage) are relatively slow and require using bus interface logic, one approach to improve performance is the use of bus register file interface 40 and bus register file 42. Bus register file 42 allows data to be stored proximately, and in association with, the localized bus 32 so that accessing the main memory is not necessary for frequently-needed values. However, this approach still places limitation on access times and system performance as explained, below, in connection with FIG. 1B.
FIG. 1B illustrates a basic pipelined instruction cycle having fetch, decode and execute stages. In FIG. 1B, pipelines 50, 60 and 70 allow concurrent execution of each stage in a manner that is known in the art. Thus, each of the fetch, decode and execute stages for different instructions or operations can be executed in a same clock cycle. This allows, e.g., the decode stage of instruction 52 to be executed at the same time as the fetch stage of instruction 62.
One drawback of this approach is that a result of an instruction is not available until the end of the execute cycle when the data is computed and stored back into a bus register. Since data is available to an instruction after the fetch stage, an instruction executing in a different pipeline may have to wait for one or more cycles before the data result of a different instruction is available. For example, FIG. 1B shows instruction 52 completing its execute stage at a time designated by line 54. However, at this time instruction 62 is past its fetch stage and so instruction 62 is delayed within the pipeline and its stages are repeated as instruction 64 so that a fetch stage is executed to obtain the data. Alternatively, the fetch stage of instruction 62 can be flushed, rescheduled, suspended, or affected in other ways, until after execution of instruction 52's execute stage. In any case, the inability of instruction 62 to have needed data at the time of its execute stage causes delays and inefficiencies in processing. The use of additional pipelines, such as pipeline 70 can compound and further complicate data accesses.
Thus, it is desirable to provide a design that improves data accesses in a digital processing architecture.

Input pipeline registers for a node in an adaptive computing engine


A convection type heat dissipation device for computers that is adjustable with respect to a heat source including a frame disposed inside the computer mainframe, the frame is connected to at least one movable tube fittingly provided on a guide duct. In use, it is only necessary to adjust the angle of an orifice portion at one side of the movable tube so that the orifice portion faces the heat source (e.g., the location of the central processing unit) within the computer mainframe. By actuating an air ventilation device located at the orifice portion, the heat generated within the computer mainframe can be quickly dissipated. Besides, the cooler ambient air may be drawn into the computer mainframe. By means of the arrangement of convection of air currents within the computer mainframe, the central processing unit and the other components of the computer may operate in a relatively low temperature and stable environment.

(a) Field of the Invention
The present invention relates generally to a heat dissipation device for computers, and more particularly to a convection type heat dissipation device that is adjustable with respect to a heat source so as to provide enhanced heat dissipation effects.
(b) Description of the Prior Art
As the processing speed of today's central processing units is quite high, when a central processing unit operates under a fully loaded state, its surface temperature may reach as high as over 100.degree. C.
Therefore, central processing units are generally equipped with cooling fans or coolers for dissipating the heat generated thereby during operation, so as to prevent the central processing unit from getting overheated, which may cause the system to become unstable or even break down.
According to the method of dissipating heat using cooling fans, the blades of the fan rotate to generate an air current which carries away with it the heat produced by the central processing unit. With conventional coolers, the cooler is fastened to the surface of the central processing unit and is made of material that may dissipate heat readily. The cooler is further provided with a plurality of blades or vanes so that it may help dissipate the heat of a larger area and effectively reduce the surface temperature of the central processing unit.
However, no matter whether cooling fans or coolers are used to help dissipate the surface heat of the central processing units, the heat dissipation efficiency is still not satisfactory. The major reasons are:
1. As the central processing unit is accommodated within an almost completely enclosed computer mainframe, the heat generated thereby cannot be continuously and effectively carried to the outside from the enclosed housing by utilizing the conventional heat dissipating devices as described above. The longer the period the central processing unit operates, the worse the effects of heat convection within the housing, resulting in low heat dissipation efficiency. PA0 2. In view of the present trend to compactize computers, the space available within the housing for accommodating the mother board will become smaller and smaller. Therefore, the dissipation of heat generated by the central processing unit becomes more a problem, and heat dissipation becomes more difficult with more compact systems. PA0 3. From the viewpoint of the present day technology development, if it is desired to raise the number of bytes processable by the central processing unit or to increase the processing speed, how to enable the central processing unit to dissipate its heat more speedily is a major concern.

Convection type heat dissipation device for computers that is adjustable with respect to a heat source

3F,No.52,Lane 280,Min Chin East Rd., Sec.6


A silver halide photographic light sensitive material is disclosed, comprising a support having thereon a silver halide emulsion layer comprising a silver halide emulsion, wherein the silver halide emulsion comprises silver halide grains having an average iodide content of 0 to 1 mol %, at least 50% of total grain projected area is accounted for by tabular grains having an aspect ratio of 2 to 20; and the silver halide grains being spectrally sensitized with a sensitizing dye represented by the following formula (1) or (2): ##STR1##

Recently, with regard to processing of a silver halide photographic light sensitive material (hereinafter, simply referred to as photographic material), shortening of processing time has been demanded. In the field of X-ray films for medical use, the amount of X-ray photographing is rapidly increasing due to increased use of X-rays for diagnosis and inspection in general medical examinations, as well as the increased tendency for periodical medical check-ups and clinical surveys. As a result, the desire for still faster processing is raised.
Shortening of processing time including developing, fixing, washing, drying, etc. is the key for faster processing of photographic materials. Shortening of the developing time alone, however, leads to a marked decrease of image density and sensitivity and deterioration of contrast. Shortening of only the fixing time leads to insufficient fixing, causing deterioration of image quality. Furthermore, shortening the time of each processing step results in incomplete dye leaching out of the processed material, causing stains due to residual dye.
To overcome these problems, it is basically required to enhance developability and fixability of the photographic material, reduce the content of the dye and promote release or decoloration of the dye.
To prevent dye stains, as is well known, it is effective to reduce the binder content. However, reduction of the binder results in marked deterioration in pressure resistance or causes problems such that when being subjected to rapid processing, abrasion marks are produced by the rollers of an automatic processor, or when being bent, pressure fogging or pressure desensitization occurs.
For environmental protection, reduction of processing effluent is required, and therefore, reduction of the amount of processing solutions and replenishing solutions or exhaustion of the processing solutions is required. In this case, however, various problems also occur similarly to the case of the above-described rapid-processing.
As techniques for solving these problems, for example, examined Japanese Patents 43-4931 and 44-16589, EP-0,506,584 (hereinafter, the term, "EP" refers to European Patent) and JP-A 5-88293 and 5-93975 (hereinafter, the term, "JP-A" refers to unexamined and published Japanese Patent Application) disclose a technique of using, as a sensitizing dye, benzimidazolo-carbocyanines which are superior in decolorizability. JP-A 5-61148 discloses a technique in which a combination of an oxacarbocyanine and benzimidazolocarbocyanine is used in a specific proportion, in a silver halide emulsion containing 1 mol % or less iodide and the silver halide emulsion is further chemically sensitized with a selenium compound and/or tellurium compound.
The dye stain reduction and rapid-processability can be improved by these techniques, but it is not insufficient to satisfy other desired levels. Specifically, since the absorption maximum of a photographic material is in a longer wavelength region and sensitivity to red light is too high, fogging due to safe-light is markedly increased. Furthermore, another defect is that when aged under high temperature and high humidity, the decrease in sensitivity is marked.
There have been made a variety of basic studies with regard to the relationship between the surface of silver halide grains and adsorption of sensitizing dyes. Phot. Sci. Eng. 18 215-225 (1974) describes that when a sensitizing dye is adsorbed to silver halide grains having (100) faces, desensitization in intrinsic sensitivity of the silver halide grains is small. It is also described that when chemical sensitization is carried out in the presence of a sensitizing dye, the chemical sensitization is controllable and desensitization in intrinsic sensitivity can be reduced. However, these techniques suggest nothing with respect to the technique of pressure resistance.
Silver halide photographic light sensitive materials generally have characteristics relating to intensity reciprocity law failure and the characteristics are variable, depending on properties of processing solutions. Specifically, low intensity reciprocity law failure is easily affected by developing agents, which results in a problem that when exposed over a long period of time, the decrease in sensitivity is markedly large, and therefore improvement in this art has been greatly desired.
Also, in the field of photographic materials for medical use, simplification and security of overall processing are being promoted to enhance working efficiency. With regard to processing chemicals, one conventional system is that a commercially available condensed processing solution is diluted to a given amount and the resulting solution is supplied as a replenisher to the processing tank of an automatic processor. As a result, the processing solution is massive in weight and volume, with the inherent disadvantages that enhancement in efficiency and safety of processing is difficult to achieve. Instead thereof, recently, there was proposed a system of solid processing chemicals, in which the processing chemicals are supplied in the form of a solid processing composition and diluent water. With this system, there have been achieved improvements in working efficiency as well as lowering of transportation cost and reduction of storage space. In addition, the amount of packaging material such as plastic resin, was advantageously reduced.
However, this system still has problems such that as processing chemicals are solid composition, its solubility (dissolution speed) is concerned and when subjected to ultra-high speed processing, stable running performance can not be achieved.
In developer used for black-and-white photographic light sensitive materials, dihydroxybenzenes such as hydroquinones have been conventionally employed as a developing agent. Recently, it was proposed to substitute ascorbic acids for the developing agent in terms of improvements in safety of working and environmental protection; for example, U.S. Pat. No. 5,236,816 discloses developing solutions employing ascorbic acid.
However, the developing solutions employing ascorbic acids are lower in activity and worse in aging deterioration than those which use hydroquinones, resulting in disadvantages that stable photographic performance can not be realized. There has been desired a silver halide photographic material developable with a developing agent such as ascorbic acid, and eliminating use of hydroquinones.


Embodiments for a capacitive sensing apparatus with attenuated electrical interference across a plurality of routing traces are provided. One embodiment forms a first sensor electrode on a substrate. In addition, a first routing trace is formed on the substrate, the first routing trace coupled with the first sensor electrode. One embodiment additionally forms a second sensor electrode on the substrate. A second routing trace differing in length from the first routing trace is also formed on the substrate, the second routing trace coupled with the second sensor electrode. To attenuate electrical interference, the second routing trace is formed having an approximately equal RC time constant characteristic as the first routing trace.

Capacitive sensing devices, otherwise known as touch sensing devices or proximity sensors are widely used in modern electronic devices/apparatus. A capacitive sensing device is often used for touch based navigation, selection, or other input, in response to a finger, stylus, or other object being placed on or in proximity to a sensor of the capacitive sensing device. In such a capacity, capacitive sensing devices are often employed in computers (e.g. notebook/laptop computers), touch screens, media players, multi-media devices, remote controls, personal digital assistants, smart devices, telephones, control consoles, and the like. Un-patterned sheet sensors (both capacitive and resistive) are often employed as a simple and economical method means for implementing attractive sensors for sensing contact, touch, and/or proximity based inputs.
However, there exist many limitations to the current state of technology with respect to capacitive sensing devices. For example, during operation a capacitive sensing device may become distorted due to the presence of noise. That is, interference sources such as LCD's and RF transmitters can corrupt signals produced by capacitive sensors within the capacitive sensing device.

Balanced resistance capacitive sensing apparatus


A reducing agent supplying device is for a fuel combustion system that includes a NOx purifying device with a reducing catalyst arranged in an exhaust passage to purify NOx contained in exhaust gas of an internal combustion engine. The reducing agent supplying device supplies a reducing agent into the exhaust passage at a position upstream of the reducing catalyst. The reducing agent supplying device includes a reforming portion and a reformation suppressing portion. The reforming portion reforms the reducing agent by partially oxidizing the reducing agent. When a temperature of the reducing agent is higher than a first specified temperature that is equal to or higher than an activation temperature of the reducing catalyst, the reformation suppressing portion (i) suppresses the degree of reformation of the reducing agent in comparison with when a temperature of the reducing agent is lower than the first specified temperature, or (ii) stops the reformation of the reducing agent.

Generally, NOx (Nitrogen Oxides) contained in exhaust gas of an internal combustion engine is purified in reaction of the NOx with a reducing agent in the presence of a reducing catalyst disposed inside an exhaust passage. For example, a Patent Literature (JP 2009-162173 A) discloses a purifying system that reforms a reducing agent by partially oxidizing the reducing agent through a plasma discharging process. The purifying system supplies the reducing agent that has an enhanced reducing capacity by the reformation into an exhaust passage at a position upstream of a reducing catalyst. By reforming the reducing agent, a NOx purification rate may be improved.


A single polarized radiator operating within a frequency range, the radiator comprising multiple active dipoles configured to be arranged a predetermined distance from a ground plane. Each active dipole comprising a first active element having first electrical characteristics and a second active element having second electrical characteristics, which first and second active elements are equal in length and provided with a respective feeding point. In each active dipole, first electrical characteristics differs from second electrical characteristics, the length of each active element is selected based on an upper frequency of the frequency range, and the first active element and/or the second active element of each active dipole is/are configured to be capacitively coupled to an active element of an adjacent active dipole.

Nodes in a wireless communication network require antennas for communication between the network and user equipment, UE, and the number of antennas varies depending on number of frequencies used, type of antenna used and how space diversity is implemented. The typical number of antennas per site is nine with three per sector. Current typical antennas are narrowband and divided into two categories, low band and mid/high band antennas. Low band covers 700-900 MHz frequency range while mid/high band covers 1700-2600 MHz. Operators are often renting site space for antennas from building landlords and tower owners, and the number of antennas, antenna size and weight are factors that determines the rental cost. More and bigger and heavier antennas results in higher rent.
One current solution to reduce number of antennas on a site is to combine low and mid/high band antennas into one antenna, known as multi band antenna. This method has drawbacks since the products become quite expensive and complicated. Since many frequency bands will be placed in same antenna this requires a lot of cabling and phase shifters, which are used for tilt. The material together with complicated building practice in order to achieve good performance results in an expensive product.
Dipole antennas are primarily used in narrowband technology in wireless communication systems. The dipoles are separated from each other to ensure that interaction between the dipoles is minimal, and each dipole array and polarization is interconnected to a common input/output port. Furthermore, each dipole is designed to cover a specific frequency band or a few bands close to each other, and a phase shifter is normally implemented per dipole to achieve vertical tilt for that dipole array. Electrical tilt is realized with an external box called Remote Electrical Tilt, RET. Realizing several frequency bands in a dipole antenna configuration requires several dipole arrays in the same antenna aperture.
An illustrative schematic of a dual polarized dual band dipole antenna 10 with phase shifters 11 operating at two different frequencies (denoted A and B) can be seen in FIG. 1. Two dual polarized antenna elements 12 are provided for each frequency, and are connected to antenna ports 13A and 13B. The number of antenna elements will differ from antenna to antenna depending on antenna characteristics.
Narrowband antennas such as described above also cause an additional challenge if wideband radios are used. This results in additional duplexers creating more site cost and power consumption increases.
Communications are currently at a premium and an exponential growth in supported services is expected over the next few years. Next generation base stations are envisioned to be able to support all wireless commercial protocols. This requires operation over a wide frequency range.
Furthermore, it is expected to offer advanced beam forming capabilities, like dedicated user beams. It is the path towards implementing an Advanced Antenna System, AAS, for commercial applications. This has generated a strong research interest for commercial wide-band wide-scan angle antenna arrays able to fulfill future base station applications.
Three main technologies stand out as prime candidates for wide-band antenna arrays. The tapered slot or Vivaldi arrays ("A parameter study of stripline-fed vivaldi notch-antenna arrays" by J. Shin and D. H. Schaubert in IEEE Transactions on Antennas and Propagation, vol. 47, no 5, pp. 879-886, May 1999), the Wheeler's concept of the infinite current sheet array and its implementations ("Simple relations derived from a phased-array antenna made of an infinite current sheet" by H. Wheeler, IEEE Transactions on Antennas and Propagation, vol. 13, no. 4, pp. 506-514, July 1965), and the fragmented array ("A new approach to broadband array design using tightly coupled elements", by M. Jones and J. Rawnick in MILCOM 2007—IEEE Military Communications Conference, October 2007, pp. 1-7).
The major problem with current wideband solutions based on Vivaldi technology is the size. The antenna elements are quite large resulting in a much thicker antenna than the traditional dipole based antenna.
The latter two have similar way of operation and mainly differ on the design procedure. Two main implementations stem from the current sheet array concept: the tightly coupled dipoles (Finite Antenna Arrays and FSS by B. Munk—IEEE. Wiley, 2003), and the connected dipoles/slots ("Scanning performances of wideband connected arrays in the presence of a backing reflector" by A. Neto, D. Cavallo, G. Gerini, and G. Toso, IEEE Transactions on Antennas and Propagation, vol. 57, no. 10, pp. 3092-3102, October 2009.).
These implementations can provide wide-band performance with moderate scanning abilities that also keeps a low visible profile. Such antenna arrays constitute a viable candidate for future base stations where it is required wide-band wide-scan angle performance, low profile and also the possibility to conform at surfaces.
Properties of non-symmetric (asymmetric) dipoles have been studied in articles. One with the title: "On the merit of asymmetric phased array elements," by H. Steyskal, published in IEEE Transactions on Antennas and Propagation, vol. 61, no. 7, pp. 3519-3524, July 2013, and another with the title: "Active element pattern symmetry for asymmetrical element arrays," by A. K. Bhattacharyya, published in 2007 IEEE Antennas and Propagation Society International Symposium, June 2007, pp. 5953-5956.


A vertical cavity surface emitting laser includes a mirror having first and second layers with first layers containing the elements aluminum, arsenic and antimony and second layers comprising the elements gallium, phosphorus and antimony. Both of these layers are lattice matched to the semiconductor material of the active zone. A VCSEL usually contains two mirrors and, preferably, both mirrors are formed of the elements as specified above. Beryllium can be used to confer p-type conductivity on one mirror and silicon to confer n-type conductivity on the other mirror. Preferably the active zone is formed of semiconductors containing at least one of indium and gallium and at least of phosphorus and arsenic. Conveniently the active zone has a lattice constant substantially equal to that of the indium phosphide and both mirrors are lattice matched to this constant.

1. Field of the Invention
This invention relates to mirrors for semiconductor laser systems and, more particularly, to vertical cavity surface emitting lasers implemented in semiconductor material systems containing at least one of indium and gallium and at least one of phosphorus and arsenic.
2. Related Art
For convenience the term "Vertical Cavity Surface Emitting Laser" is shortened to VCSEL.
The structure of a VCSEL includes two mirrors, e.g. distributed Bragg reflectors, which are located at opposite ends of the lasing zone. In some VCSELs the mirrors are part of the electrical system. The mirrors are required to maintain the lasing process by returning light back to the active region to stimulate more emission. To achieve satisfactory lasing performance VCSELs require good performance from the mirrors and the combined effect of the two mirrors is important. Reflectivities exceeding 99% are usually regarded as necessary. The reflectivity of the two mirrors may be different. The use of two high reflectivity mirrors, e.g. more than 99.5%, is, of course, desirable but other considerations sometimes make it appropriate to use a lower performance mirror in conjunction with a higher performance mirror.
At least one of the mirrors, identified as the "front mirror" in this specification, is required to transmit a suitable proportion of the radiation to act as the output of the VCSEL. For the front mirror 100% reflectivity is, therefore, not appropriate. It is convenient to call the other mirror the "rear mirror".
In order to provide the appropriate reflectivities the mirrors are usually implemented as several layers of suitable semiconductor material. More specifically, two different materials are utilised in the mirrors. The optical and physical theory suggests suitable refractive indices for the materials and the number of layers required to provide a given reflectivity. However the physical theory provides little help in identifying suitable materials for the two layers. More particularly, the physical theory does not help to define the chemical composition of the two layers.
In addition to providing appropriate refractive indices the following material properties are appropriate.
(A) The lattice constant of the mirror material must match the lattice constant of the lasing zone. Usually the lasing zone has a lattice constant substantially equal to that of indium phosphide and, therefore, is it desirable that the mirror match this constant. PA0 (B) The mirrors work by reflecting radiation from internal interfaces in such a manner that multiple reflections reinforce one another. Thus it is necessary for reflected radiation to pass through the layers of the mirror. In fact there is a double pass because incident radiation traverses the layers on the way in and reflected radiation repeats the traverse on the way out. Therefore, high reflectivities require that the layers must have good transmission properties. (The ideal would be 100% but this may not always be achieved in practice.) In addition, the output of the device traverses the front mirror and this is another reason why high transmission is needed. PA0 (C) VCSELs are technically and commercially significant because they are relatively cheap to manufacture. The radiation is transmitted normal to the substrate and the various epitaxial planes. This means that the lasers can be operated in the wafer before division. This is valuable for testing. It is also important for those applications which require an array of lasers. PA0 (D) It is also important that the materials from which the mirrors are made are stable and have an adequate life. In a VCSELs the mirrors define the limits of the lasing system and, in some VCSELs, the mirrors are part of the electrical system, e.g. they transmit the drive current. For this reason it is appropriate to form the mirrors out of semiconductor materials. PA0 (E) When the mirrors are part of the electrical system, the materials from which they are made should have adequate electrical conductivity. It is usually necessary to be able to provide both p-type and n-type conductivity. Thus it is desirable to select semiconductor materials which are able to be doped so as to provide either p-type or n-type conductivity as required.
It is difficult to select materials which offer adequate performance in respect of all of these requirements. This invention relates to semiconductor materials which are at least adequate in respect of all of them.
In Electronic Letters published 16th January 1997, Volume 3 (No. 2) at pages 140 and 141 Genty et al described high reflectivity distributed Bragg reflector structures for 1.5 .mu.m surface emitting lasers. The reflector structures are composed of alternate layers of Te-doped GaAsSb and un-doped AlAsSb. It is stated that the Te-doping gives the structure n-type conductivity. Without the doping the GaAsSb is highly absorbent. FIG. 2 of the publication shows that a maximum reflectivity exceeding 94% was measured on a mirror with only 11.5 period in the stack. FIG. 2 also shows that, even with n-type doped layers, there is low reflectivity at wavelengths below 1.4 .mu.m.
Anan et al in Electronic Letters 30, 2138 (1994), describe mirrors comprising AIPSb in one layer and GaPSb in the other layer.

British Telecommunications public limited company


A system for controlling at least one machine at a work site includes a controller configured to store a map of a boundary of a work area at the work site. The controller determines a first arrival time for a first machine to arrive at the boundary and a second arrival time for a second machine to arrive at the boundary. An arrival interval is determined based upon a difference between the first arrival time and the second arrival time the relative travel speed between the first machine and the second machine is adjusted so that the machines arrive at a desired arrival interval.

Machines such as dozers, motor graders, wheel loaders, etc., are used to perform a variety of tasks. For example, these machines may be used to move material at a work site. The machines may operate in an autonomous or semi-autonomous manner to perform these tasks in response to commands generated as part of a work plan for the machines. The machines may receive instructions in accordance with a work plan to perform operations including digging, loosening, carrying, etc., different materials at the work site, such as those related to mining, earthmoving and other industrial activities.
Autonomously operated machines may remain consistently productive without regard to a human operator or environmental conditions. In addition, autonomous systems may permit operation in environments that are unsuitable or undesirable for a human operator. Autonomous or semi-autonomous systems may also compensate for inexperienced human operators as well as inefficiencies associated with repetitive tasks.
In some circumstances, machines may be operated autonomously in one area of a work site and by remote control in a second area. An operator may be responsible for remotely controlling more than one machine at the second area. If the operator is already remotely controlling one machine as a second machine approaches the second area, the second machine will be required to idle and wait for the operator to complete the remote operation of the first machine. Idling while waiting for the remote control operator may increase fuel usage and cause additional wear when propulsion of the machine resumes.
U.S. Pat. No. 6,845,311 discloses a control system for a work machine. A positioning system determines a relative location of the work machine within a work site and produces a machine position signal. A site model contains data related to a condition of the material at the work site. A controller of the control system is coupled to the site model, receives the machine position signal, determines a current condition of the material as a function of the position signal and the site model, and controls the work machine as a function of the current condition of the material.
The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims.

System and method for controlling the operation of a machine


Methods and apparatus for coupling lenses and frames, and eyeglasses, are provided in which a flexible washer (34) is compressed to engage a lens (16).

Eyeglasses generally comprise two lenses and a frame. Examples of frames include, without limitation, those that retain the lenses by holding them in a groove around the perimeter of the lenses, and three-piece frames that include two ear pieces and a nose bridge attached to the lenses (such as shown in prior art FIG. 1).
Whatever the frame style, it is often desirable to change the lenses held by the frame. For example, a wearer's prescription may change, or lenses may become damaged, thus motivating lens changes. Or, different lenses may be suitable for different environments or uses, and a wearer may desire to change out lenses accordingly, while using the same frame. For example, and without limitation, a wearer may desire to change from sunglasses lenses to lenses with a bifocal reader segment, or from lenses with one color tint to another color tint.
Initial coupling of frames and lenses, which is generally performed by eyeglass professionals, is relatively precise work and can be difficult. For example, with three-piece drill-mount frames, the frames are often attached to the lenses by drilling holes in the lenses, and passing shafts from the frames through the holes. In some cases, the shafts are threaded to accommodate a nut for securing the attachment. In other cases, the shafts are pressed into a receiving cap to secure the lens attachment. Whatever the approach, later changing of the lenses is not easily accomplished.
Therefore, a need has arisen for improved methods and apparatus for coupling lenses and frames, and improved eyeglasses.

Methods and apparatus for lenses and frames and eyeglasses


A wrist rest support system for supporting a wrist rest beyond the edge of a working surface, including an extension clamp having a cantilever plate having a first end member proximate the working surface and a second end member, the second end member having a distal end cantilevered away from the working surface. Each end member has a separate longitudinal axis spaced laterally apart. The longitudinal axes are approximately parallel. A fastener for attaching the cantilevered plate to the working surface is connected to the first end member of the cantilever plate. The second end of the cantilever plate has a groove proximately perpendicular to the second axis. The groove is for receiving a sculpted portion of a base member of the wrist rest. A retaining member is disposed upwardly at the distal end of the second end member. The retaining member is for retaining the wrist rest on the second end member.

Wrist rests are well known in the art. Wrist rests can be used for a variety of purposes, but one of the most common is for operating a keyboard. While operating a keyboard, a person's wrists are generally unsupported. If this activity is continued for a long period of time, injuries such as carpal tunnel syndrome may result. The wrist rest encourages the user to maintain a neutral wrist position. Often, however, working surfaces or spaces are not large enough to accommodate the wrist rest.
The present invention addresses this problem with the prior art and provides for a wrist rest support system which is easily adjustable to accommodate a variety of working surfaces and spaces.


In a semiconductor device and a method of manufacturing the same, a conductive structure is formed on an active region defined by a device isolation layer on a semiconductor substrate. The conductive structure includes a gate pattern and source/drain regions adjacent to the gate pattern. A first semiconductor layer is formed on the active region by a selective epitaxial growth (SEG) process. An amorphous layer is formed on the first semiconductor layer. A second semiconductor layer is formed from a portion of the amorphous layer by a solid-phase epitaxy (SPE) process. Elevated structures are formed on the source/drain regions by removing a remaining portion of the amorphous layer from the substrate, so the elevated structure includes the first semiconductor layer and the second semiconductor layer stacked on the first semiconductor layer. The device isolation layer may be prevented from being covered with the elevated structures, to thereby prevent contact failures.

1. Technical Field
Example embodiments relate to a semiconductor device and to a method of manufacturing the same and, more particularly, to a semiconductor device having elevated source/drain (ESD) structures, and to a method of manufacturing the same.
2. Description of the Related Art
Due to the high degrees of integration of recent semiconductor devices decreased design rules for various elements of the semiconductor devices may now be required. However, the decreased design rules may cause transistors to have short channels and small contact areas between the transistors and various conductive structures. Particularly, the operational characteristics of a semiconductor memory device may be significantly influenced by a short channel and a small contact area of a transistor, because the semiconductor memory device may include a large number of transistors.
A short channel of the transistor may cause a short channel effect in the transistor, and thus a leakage current may be increased in the transistor and a refresh time may not be sufficiently obtained in a memory device. The small contact area may in turn cause contact resistance to increase at both the source electrode and the drain electrode of the transistor, and cause the process margin of a critical dimension to be reduced, to thereby generate a contact failure.
Consequently, various types of research have been conducted for enlarging the contact area at source/drain regions so as to reduce contact resistance at the source/drain regions. As a result of the above-mentioned research, an elevated source/drain (ESD) structure has been suggested and most widely used for enlarging a contact area at source/drain regions. A conventional ESD structure may include a stacked gate electrode having a spacer at both side walls thereof and epitaxial layers selectively grown at surface portions of an active region adjacent to the gate electrode.
However, as a conventional selective epitaxial growth (SEG) process is an isotropic process, the conventional ESD structure grows at the same rate both in a vertical direction perpendicular to the substrate and in a horizontal direction parallel with the substrate. Accordingly, the conventional ESD structure may have difficulties associated therewith in that the device isolation layer may be covered with the ESD structures and the source and drain regions of the active region adjacent to each other may not be electrically separated from each other.
FIG. 1 is a plan view illustrating a semiconductor device including a conventional ESD structure. In FIG. 1, a dash line indicates an active region before the source/drain regions are elevated and a dotted line indicates an active region of which the contact area is enlarged due to the elevation of the source/drain regions.
Referring to FIG. 1, a gate structure (not shown) is formed on a semiconductor substrate 10 in which a gate oxide layer and a gate stack are stacked on the substrate 10 and a gate spacer is formed at both side walls of the gate stack. The substrate 10 includes an active region 12 in which a conductive structure is positioned as a unit device for an electric circuit and a device isolation region 14 by which adjacent active regions are electrically isolated from each other; and thus the conductive structures on the adjacent active regions may be electrically isolated from each other. In general, an insulation layer (not shown) is formed in the device isolation region 14 by a shallow trench isolation (STI) process, to thereby form a device isolation layer (not shown) in the device isolation region 14 for electrically isolating the conductive structures on the adjacent active regions 12 from each other.
The source/drain regions adjacent to the gate structure are enlarged to an expanded area 12b from an original area 12a by a SEG process, and thus the contact area may be enlarged and the contact failures may be significantly reduced in the semiconductor device.
A SEG process is an anisotropic process, and thus a SEG layer may not be formed on the device isolation layer comprising oxide or nitride. However, as the design rule of a semiconductor device is decreased, the SEG process may be gradually transformed into an isotropic process in place of an ideal anisotropic process, and thus the device isolation layer may be partially covered with an epitaxial layer.
That is, the epitaxial layer of the ESD structure extends to an upper portion of the device isolation layer defining the active regions, so that the source/drain regions of the adjacent gate structures are not electrically separated from each other by the device isolation layer. Therefore, when contact plugs are formed on the ESD regions, adjacent contact plugs may be electrically connected to each other, and thus the adjacent source and drain regions may be electrically connected to each other, to thereby generate a 2-bit failure in the semiconductor device.
FIG. 2A is a cross-sectional view taken along a line I-I′ of a portion A of the semiconductor device shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along a line II-II′ of a portion B of the semiconductor device shown in FIG. 1.
Referring to FIG. 2A, when the adjacent gate structures 20a and 20b are spaced apart from each other by a sufficient gap distance, epitaxial layers 30 grown at the source and drain regions may be sufficiently separated from each other to thereby form an elevated source region 34 and an elevated drain region 32 on the substrate 10. Thus, the elevated regions 34 and 32 at the source and drain regions may sufficiently function as source and drain regions for the adjacent gate structures 20a and 20b. A conductive structure such as a contact plug is individually formed on the elevated source and drain regions 34 and 32 and each of the conductive structures may be electrically operated independently from each other.
However, as shown in FIG. 2B, when the adjacent gate structures 20a and 20b are not sufficiently spaced apart from each other, the epitaxial layer is grown to cover the whole surface of the device isolation layer, and thus the device isolation layer may be fully covered with the epitaxial layer 30. Thus, the elevated drain region 32 for the first gate structure 20a may not be separated from the elevated source region 34 for the second gate structure 20b, and each of the contact plugs located on the elevated source and drain regions 34 and 32, respectively, may also electrically separated from each other, to thereby generate a bridge defect. As a result, the first and the second gate structures 20a and 20b may not be electrically separated from each other to thereby generate the 2-bit failure in the semiconductor device.
Accordingly, there is still a need for an improved method of forming an ESD structure in which lateral growth is sufficiently prevented on a surface of the substrate to thereby reduce contact failures such as the bridge defect.

Method of manufacturing a semiconductor device


A system and method are provided for processing to create distributed volume in a distributed storage system during a failure that has partitioned the distributed volume (e.g. an array failure, a site failure and/or an inter-site network failure). In an embodiment, the system described herein may provide for continuing distributed storage processing in response to I/O requests from a source by creating the local parts of the distributed storage during the failure, and, when the remote site or inter-site network return to availability, the remaining part of the distributed volume is automatically created. The system may include an automatic rebuild to make sure that all parts of the distributed volume are consistent again. The processing may be transparent to the source of the I/O requests.

In current storage networks, and particularly storage networks including geographically remote directors (or nodes) and storage resources, preserving or reducing bandwidth between resources and directors while providing optimized data availability and access is highly desirable. Data access may be localized, in part, to improve access speed to pages requested by host devices. Caching pages at directors provides localization, however, it is desirable that the cached data be kept coherent with respect to modifications at other directors that may be caching the same data. An example of a system for providing distributed cache coherence is described in U.S. Pat. No. 7,975,018 to Unrau et al., entitled "Systems and Methods for Providing Distributed Cache Coherency," which is incorporated herein by reference. Other systems and techniques for managing and sharing storage array functions among multiple storage groups in a storage network are described, for example, in U.S. Pat. No. 7,266,706 to Brown et al. entitled "Methods and Systems for Implementing Shared Disk Array Management Functions," which is incorporated herein by reference.
Data transfer among storage devices, including transfers for data replication or mirroring functions, may involve various data synchronization processing and techniques to provide reliable protection copies of data among a source site and a destination site. In synchronous transfers, data may be transmitted to a remote site and an acknowledgement of a successful write is transmitted synchronously with the completion thereof. In asynchronous transfers, a data transfer process may be initiated and a data write may be acknowledged before the data is actually transferred to directors at the remote site. Asynchronous transfers may occur in connection with sites located geographically distant from each other. Asynchronous distances may be distances in which asynchronous transfers are used because synchronous transfers would take more time than is preferable or desired. Particularly for asynchronous transfers, it is desirable to maintain a proper ordering of writes such that any errors or failures that occur during data transfer may be properly identified and addressed such that, for example, incomplete data writes be reversed or rolled back to a consistent data state as necessary. Reference is made, for example, to U.S. Pat. No. 7,475,207 to Bromling et al. entitled "Maintaining Write Order Fidelity on a Multi-Writer System," which is incorporated herein by reference, that discusses features for maintaining write order fidelity (WOF) in an active/active system in which a plurality of directors (i.e. controllers and/or access nodes) at geographically separate sites can concurrently read and/or write data in a distributed data system. Discussions of data ordering techniques for synchronous and asynchronous data replication processing for other types of systems, including types of remote data facility (RDF) systems produced by EMC Corporation of Hopkinton, Mass., may be found, for example, in U.S. Pat. No. 7,613,890 to Meiri, entitled "Consistent Replication Across Multiple Storage Devices," U.S. Pat. No. 7,054,883 to Meiri et al., entitled "Virtual Ordered Writes for Multiple Storage Devices," and U.S. Pat. No. 8,335,899 to Meiri et al., entitled "Active/Active Remote Synchronous Mirroring," which are all incorporated herein by reference and are assigned to the assignee of the present application.
Under known distributed storage volume processing, distributed storage volumes may not be automatically created during a site failure, an array failure and/or an inter-site network failure that has partitioned the distributed volume. When an administrator wants to create a distributed storage volume that spans two backend arrays where one of the backend arrays is missing (e.g. as a result of the site failure, an array failure and/or the inter-site network failure), the administrator has to change the workflow to (1) create a volume on the available array; (2) export the local volume for I/O processing; (3) wait for the other array to reappear or otherwise become again available; (3) create a volume on the reappeared array; and (4) upgrade the local volume to a the distributed one. This process relies on the administrator and may be error-prone.
Accordingly, it would be desirable to provide an effective and efficient system to address issues like that noted above for a distributed storage system.

This patent is subject to a terminal disclaimer.

Creating distributed storage during partitions


A universal antenna mounting system includes a grid-like mounting frame on which the antenna is installed. A mounting pipe is secured to a tower leg at a desired height and the mounting frame is then secured to the mounting pipe. The mounting connections are all frictional in nature and the mounting frame is adjustable in azimuth about the mounting pipe so that the antenna can be pointed in the right direction. Side struts secured to the mounting frame and the tower maintain the mounting frame at the desired azimuth.

This invention relates to antenna installation and, more particularly, to an improved system for mounting an antenna on a tower.
Cellular communications antennas are typically mounted on towers so that they are elevated above ground level to increase their line-of-sight range. Such an antenna is highly directional and therefore must be pointed in a very specific direction. If the antenna is mounted on a tower, the angular orientation of the tower may not be in the specific direction required by the antenna. This is especially true when the tower is preexisting. It would therefore be desirable to have an antenna mounting arrangement which is angularly adjustable in a horizontal plane to accurately point the antenna in a desired direction.
It would also be desirable to have an antenna mounting system which can be installed at any desired height on a tower.
It would be further desirable to have an antenna mounting system which provides safe accessibility to the antenna.
It would additionally be desirable to have an antenna mounting system which is adaptable for mounting on a wide variety of towers.


The present invention employs a bias voltage having a selectable magnitude to bias a weak write pull-down transistor in a write driver of a static random access memory (SRAM) array. A programmable weak write test mode (PWWTM) bias generator includes an output signal that is a logic high in a default mode when a WWTM is not active. When the WWTM is active, the generator output signal is the bias voltage having the selectable magnitude. The default mode logic high is actively maintained when the generator output is connected to a load, such as the write driver of the SRAM array. A WWTM-enabled SRAM system includes the PWWTM bias generator. A method of driving a WWTM-equipped SRAM includes generating and applying the output signal to a gate of a weak write pull-down transistor of the SRAM array write driver in the default mode and the WWTM.

Among the typical tests that are performed on SRAM arrays are tests for memory cell data retention faults (DRFs) and memory cell stability faults. In particular, DRFs and stability faults often result from variations in manufacturing materials and processes. In the past, DRF and stability fault testing has been largely functional in nature. Namely, a read/write algorithm is developed that functionally exercises the SRAM. The read/write algorithm is then executed by a memory test system external to the IC. From the results of the functional testing, an attempt is made to deduce DRFs and stability faults for individual memory cells in the SRAM.
Recently, several test methodologies have been developed that directly test for such failures instead of inferring the failures from functional tests. Moreover, some of these test methodologies are well-suited to being implemented as a built-in self-test (BIST), such that the cost and time associated with testing for DRF and stability faults using an external memory test system are reduced or effectively eliminated. One such methodology known as Weak Write Test Mode (WWTM) is disclosed by Banik et al., U.S. Pat. No. 5,559,745, incorporated herein by reference.
When testing an SRAM with WWTM, an attempt is made to overwrite a data value stored in a memory cell using a "weak" write value or signal. The weak write signal is only capable of overwriting the stored value in the memory cell if the memory cell is unstable or defective. Thus, if the weak write test is successful, a defect in the memory cell is indicated. An unsuccessful weak write test indicates a healthy memory cell, at least with respect to stability and DRFs.
Weiss et al., U.S. Pat. No. 6,192,001 B1, incorporated herein by reference, disclose a WWTM approach that integrates a weak write driver functionality into an existing conventional column-associated write driver of the SRAM. According to Weiss et al., only two additional transistors are added to each conventional write driver in each set of columns as opposed to six transistors per column according to Banik et al. A set of columns is one or more columns depending on whether or not column multiplexing is employed in the SRAM. In particular, a first or weak write pull-down transistor is added that modifies a level of an output signal of the write driver when in WWTM and a second or bypass pull-down transistor is added that essentially bypasses the first transistor thereby facilitating a normal or strong write output signal to be produced by the write driver when not in WWTM.
Unfortunately, sizing of the weak write pull-down transistor of Weiss et al. presents certain practical difficulties in IC manufacturing. In particular, the weak write pull-down transistor must be big or strong enough to insure that the WWTM write driver output signal adequately exercises the memory cells of the SRAM, allowing for reliable detection of defective memory cells. Simultaneously, the weak write pull-down transistor must be small or weak enough such that the WWTM write driver output signal is not capable of overwriting data in healthy memory cells thereby producing false detection of defects.
In practice, the weak write pull-down transistor sizing is sensitive to variables and tolerances of a given manufacturing line and/or inadequacies of a design simulation to account for such variables and tolerances. Thus, many memory design and prototype iterations may be necessary to produce a properly sized weak write pull-down transistor. Moreover, each time the IC design is changed and/or the manufacturing process/line is changed or modified, the iterative design process typically must be repeated.
Accordingly, it would be advantageous to have a way to implement WWTM that was less sensitive to weak write pull-down transistor sizing. In addition, it would be advantageous if such implementations did not appreciably increase the number of transistors in the SRAM array or a number of traces in the SRAM IC used to access and activate WWTM. Such an implementation of WWTM would solve a long-standing need in the area of BIST for ICs that contain SRAM arrays.

Programmable weak write test mode (PWWTM) bias generation having logic high output default mode

Hewlett-Packard Development Company, L.P.


Approaches for deciding what individuals in a population of visual system “neurons” are looking for using sparse overcomplete feature dictionaries are provided. A sparse overcomplete feature dictionary may be learned for an image dataset and a local sparse representation of the image dataset may be built using the learned feature dictionary. A local maximum pooling operation may be applied on the local sparse representation to produce a translation-tolerant representation of the image dataset. An object may then be classified and/or clustered within the translation-tolerant representation of the image dataset using a supervised classification algorithm and/or an unsupervised clustering algorithm.

Recent developments in machine vision have demonstrated remarkable improvements in the ability of computers to properly identify particular objects in a viewing field. However, most of these advances rely on color-texture analyses that require targets objects to possess one or more highly distinctive, local features that can be used as distinguishing characteristics for a classification algorithm. Many objects, however, consist of materials that are widely prevalent across a wide variety of object categories.
The human visual system is one of the archetypal models of sensor fusion. Populations of specialized cells in the retina, thalamus, and cortex act as sensors responding in parallel to complementary attributes of the objects in view, such as spatial boundaries and grayscale textures, color signatures, motion cues, and depth cues from stereopsis. Information in these complimentary channels is fused in higher regions of the cortex, providing a rich representation of the world, even before additional fusion of information from other sense organs is provided, such as sense information from sound or touch. Neuroscience has revealed many properties of individual neurons and of the functional organization of the visual system that are believed to be essential to reach human vision performance, but are missing in standard artificial neural networks. Among these are extensive lateral and feedback connectivity between neurons, spiking dynamics of neurons, and sparse patterns across populations of neurons.
Equally important may be the scale of the visual cortex and the amount of visual input it receives. The human visual cortex consists of approximately 10 billion neurons, each with approximately 10,000 synaptic connections. A simple simulation at 10 flops per neuron to process one frame of data therefore requires approximately one petaflop (1015 flops) of computation. In a year, the 6 million cones in an eye's retina and approximately 1 million fibers in the optic nerve deliver approximately one petapixel of information to the brain.
Computing hardware to support full scale implementations of hierarchical models for large scale datasets now exist. The Petascale Synthetic Visual Cognition team at Los Alamos National Laboratory (LANL) has developed large scale functional models of the visual cortex called Petascale Artificial Neural Network (PANN) that can operate on LANL's Roadrunner petaflop supercomputer, and on graphical processer unit (GPU) accelerated clusters. An initial run of a simple visual cortex (V1) code on Roadrunner achieved 1.144 petaflops during trials at the IBM facility in Poughkeepsie, N.Y. in June of 2008. The example PANN model also achieved real-time processing of grayscale high definition video (1080 p) on a cluster of 16 computer nodes, each accelerated by a graphics processing unit (GPU) (e.g., NVIDIA Fermi™). This scale of computing is often preferable for applications that require processing of regional-scale satellite imagery collections, for climate change studies, for disaster response, etc.
However, conventional approaches use large numbers of parameters in their models. For instance, some approaches use from 60 million to a billion parameters, and, in the latter case, approximately 16,000 computers are required to process a 200×200 pixel dataset. Accordingly, an improved approach to image processing may be beneficial.

Image fusion using sparse overcomplete feature dictionaries


A method for selectively photoionizing odd mass Zr atoms. Atomic vapours are subjected to three resonant and are non resonant laser pulses to raise the energy of Zr atoms from the J=2 ground state, to a J=1 first intermediate state, to a J=(second intermediate state and to a third intermediate state prior to ionization. Quantum mechanical selection rules applicable to linearly polarized light and hyperfine interactions are exploited to produce odd mass selectivity

Zirconium is commonly used for forming fuel cladding, pressure tubing and other components of nuclear reactors. Zirconium is useful for such applications because of its relatively low neutron capture cross-section. The neutron capture cross-section of natural zirconium is dominated by the .sup.91 Zr isotope. The fuel economy of a nuclear reactor can be greatly improved by using .sup.91 Zr depleted zirconium in place of natural zirconium. Reduction of .sup.91 Zr in natural zirconium, containing typical alloying impurities, from its natural abundance of about 11% to 3% corresponds to a reduction in effective cross-section from 0.244 barns to 0.15 barns. Further reduction of .sup.91 Zr to 1% corresponds to a reduction in effective cross-section to 0.12 barns. The use of .sup.91 Zr depleted zirconium not only allows improved fuel efficiency, but also allows the use of thicker pressure and calandria tubes reducing tube sag and increasing safety margins. As a result, a substantial saving in the costs of retubing reactors can be realized.
Techniques exist for isotopically selective excitation and ionization of various elements. Enrichment of the uranium isotope, .sup.235 U, for nuclear power plant fuel can be achieved by atomic vapour laser isotope separation (U-AVLIS). In the U-AVLIS process, uranium metal is heated to over 2000.degree. C. to form dense atomic vapours. Dye laser beams, tuned to excite preferentially and ionize the .sup.235 U isotope, are passed through the atomic vapours. The ions, enriched in .sup.235 U are electrostatically separated from the depleted neutrals and collected. The isotopic selectivity obtained in the U-AVLIS process is very high, e.g. >10.sup.4, because the spectral shifts between the .sup.235 U and .sup.238 U isotopes are much larger than the laser bandwidths. The lasers are precisely tuned to the frequency of the .sup.235 U transition to excite selectively and ionize this isotope. This approach is not practical for Zr because the isotope shifts are much smaller than the bandwidths of the lasers typically used for U-AVLIS. While lasers of sufficient resolution are available, they are characterized by very low power and hence produce unacceptably low yields for a practical .sup.91 Zr depletion process.
As a result, techniques for .sup.91 Zr depletion that do not depend on isotope shift discrimination have been proposed. U.S. Pat. No. 4,389,292, Phillips et al. issued Jun. 21, 1983 discloses a photochemical process for separating .sup.91 Zr by raising a zirconium chelate ligand from a ground state to an activated state in the presence of a scavenger which reacts with the ligand in the activated state but not in the ground state and separating out the reacted ligand. U.S. Pat. No. 4,584,073, Lahoda et al. issued Apr. 22, 1986 discloses a process for separating .sup.90 Zr by coating small bead particles with a zirconium compound such as zirconium tetrachloride and photoexciting said zirconium compound to cause a reaction of one isotope compound thereof with a scavenger gas.
Non-chemical processes for separating odd from even atomic weight isotopes using polarization selection rules are also known. In a paper entitled "Use of Angular-Momentum Selection Rules for Laser Isotope Separation", Appl. Phys. Lett. 29, 411 (1976), Balling and Wright discuss a technique for isotope-selective laser excitation of atoms which exploits the angular-momentum selection rules for the absorption of circularly polarized light. Resolved hyperfine levels are populated by stepwise excitation with two circularly polarized lasers tuned to the appropriate absorption lines. The Balling and Wright technique is stated to be effective for group III atoms and Yb. This technique requires strong hyperfine interaction and resolvable hyperfine levels. For zirconium, which has an atomic ground state of J=2, weak hyperfine interaction and many unresolvable hyperfine levels, the Balling and Wright technique will not work efficiently. The ground state is characterized by a population of zirconium diluted over many hyperfine levels, only one of which can be accessed at a time.
In U.S. Pat. No. 4,020,350, Ducas issued Apr. 26, 1977, there is described a method for the selective excitation of odd atomic weight isotopes employing two pulsed lasers having the same handedness of circular polarization. The first laser pulse creates a coherent superposition state in an intermediate level. After the laser pulse is terminated, resonance oscillation due to hyperfine structure causes the population of the odd atomic weight isotope to be redistributed whereas the population of the even atomic weight isotope is not. According to selection rules, a second laser pulse having the same handedness of circular polarization can excite the redistributed odd atomic weight isotopes out of the intermediate state into a high lying level from which the atoms can be ionized. Although the Ducas method is described as being valid for a wide variety of more complex level structures, it is clear that such method applies only for states having relatively low J and I. This is because the Ducas method requires that the time between application of the laser pulses be set at t=.pi./.DELTA..omega. where .DELTA..omega. is the characteristic period of the frequency splitting. For zirconium which has a I=5/2 and a J=2 ground state, there exist a multiplicity (2J+1) (2I+1) of .DELTA..omega.'s which interfere in such a way that there is no single definable W. The result is that the Ducas method would likely produce unacceptably low separation factors when applied to zirconium.
In a paper entitled "Effect of a Magnetic Field on the Resonant Multistep Selective Photoionization of Gadolinium Isotopes", Optics Communications, Vol. 76, No. 1, Apr. 1, 1990, Guyadec et al. disclose a multistep photoionization process for separating odd and even isotopes of gadolinium. Guyadec et al. selectively photoionizes odd isotopes (.sup.155 Gd, .sup.157 Gd), but requires the use of an autoionizing level. This level is very susceptible to external electric and magnetic fields and Helmholtz coils are required to control the magnetic field. In hostile environments typical of apparatus used to generate atomic vapours for separation, such as in an electron beam furnace, interfering electric and magnetic fields are practically difficult or impossible to control. Such fields redistribute the sublevel populations in the even isotope and destroy selectivity.
In a paper entitled "Selective ionization of Ba and Sr isotopes based on a two photon interference effect", Physical Review A, Vol. 42, No. 1, Jul. 1, 1990, Park and Diebold disclose the selective ionization of nonzero-spin atoms relative to zero-spin atoms. Park and Diebold use a two-photon resonant sequence stated to be effective for separating Ba and Sr isotopes.
None of the above discussed references discloses a method for selective photo excitation and ionization of .sup.91 Zr from natural zirconium suitable for production purposes.

Zirconium isotope separation using tuned laser beams

Atomic Energy of Canada Limited/Energie Atomique du Canada Limitee


A smart storage container apparatus and method, the apparatus comprising at least one storage compartment and a display, and is configured to download basic local configuration information corresponding to the apparatus, locally adjust the downloaded information according to local conditions of content of the at least one storage compartment, and based on the adjusted configuration information, adapt a local configuration database. Additionally, a method comprising downloading basic local configuration information corresponding to a smart storage apparatus comprising, locally adjusting the downloaded information according to local conditions of content of the at least one storage compartment, and based on the adjusted configuration information, adapting a local configuration database.

Some known first aid kits include lists of contents, some with illustrative drawings. Additionally, there are known first aid guides. However, it is usually not practical to continuously monitor which equipment is missing and/or dislocated. Additionally, identifying in emergency condition exactly which equipment can be used for the specific condition and where it is stored, may cost expensive time and risk lives.

Smart storage container apparatus, system and method thereof