To generate a satisfactory recording magnetic domain on a recording medium and to improve the durability of a recording head, an information recording apparatus for generating an optical near field and thermo-magnetically recording information on the recording medium is provided with a light source, a magnetic pole for applying a magnetic field to the recording medium and a diffuser that generates an optical near field in the vicinity of the recording medium when light from the light source is radiated. The diffuser is formed with it in contact with the magnetic pole so that the face which light from the light source irradiates is substantially perpendicular to the recording medium. Thereby, recording density in the information recording apparatus can be increased, simultaneously the reliability can be also enhanced and as a result, the cost can be reduced.

1. Field of the Invention
The present invention relates to a recording head provided with a function for optically or thermally exciting a magnetic recording medium, locally reducing the coercivity of the recording medium and thermo-magnetically recording information and an information recording apparatus using it.
2. Description of the Related Art
In Japanese published unexamined patent application No. Hei10-162444, "Magneto-optical recording medium, recording/reading method and recording/reading apparatus" (first prior art), technique utilizing a head using a solid immersion lens in a recording/reading apparatus for recording a hyperfine magnetic domain signal at a hyperfine light beam spot on a magneto-optical disk is disclosed.
Besides, in Japanese published unexamined patent application No. 2001-255254, "Optical near field probe, optical near field optical microscope using it and optical recording/reading apparatus" (second prior art), technique related to an optical near field probe formed by a metal diffuser in a shape of a cone or a triangle formed on a substrate and a metallic, dielectric or semiconductor film formed around the diffuser and having the same thickness as the height of the diffuser and optical recording using it is disclosed.
Further, in Japanese published unexamined patent application No. 2002-48697, "Optical near field probe and its manufacturing method" (third prior art), a method of manufacturing a flat optical near field probe in which a metal diffuser is buried in a dielectric and the mean surface roughness of which is approximately 10 nm or less is disclosed.
In a recording head provided with a function for optically or thermally exciting a recording medium to change a local physical state of the recording medium and recording information and an information recording apparatus using it, a method of using a light spot stopped down up to a diffraction limit using a lens is general. In this case, the size of the light spot is approximately λ/NA when the wavelength of a light source is λ and the numerical aperture of the lens is NA and the magnitude determines the size of an area (a so-called recording mark) in which a physical state is changed on the recording medium, that is, recording density. To increase recording density, directly the wavelength of the light source is reduced or the numerical aperture is widened, however, the development of a light source having a shorter wavelength has an extremely great problem in the material of a light source element and the efficiency of emission and the numerical aperture cannot be theoretically made larger than 1. Therefore, in information recording depending upon the light spot at the diffraction limit, there is great difficulty to increase recording density.
To conquer the difficulty, thermomagnetic information recording technique using an optical near field disclosed in the first prior art is developed. That is, the diameter of the light spot used in recording is reduced from λ/NA further to 1/n or 1/n^2 (^: power) by using the solid immersion lens made of material the refractive index of which is n so as to increase recording density. However, a high refractive index and low absorptance in a wavelength of a combined light source are required for material forming the solid immersion lens. In case a violet semiconductor laser having the shortest wavelength currently realized as a light source for recording for example is used, λ is approximately 405 nm, however, the refractive index of optical glass that hardly absorbs in this waveband is approximately 2 and even if the optical glass is combined with a lens NA of which is 0.9, the diameter of the light spot is reduced only to approximately 110 nm. Therefore, it is difficult to stably form a recording mark in size by far smaller than the diameter of the light spot and the solid immersion lens has a limit in increasing recording density.
To conquer the limit in the first prior art, technique for generating an optical near field using a metal diffuser disclosed in the second and third prior arts is developed. As the distribution size of an optical near field equivalent to the diameter of a light spot is determined by the manufacuring precision of the metal diffuser in the prior arts, the distribution size of an optical near field can be greatly reduced by using high-resolution lithography depending upon an electron beam lithography, compared with the diameter of a light spot by the solid immersion lens. However, in these prior arts, the metal diffuser that generates an optical near field is exposed at the bottom of the recording slider and has structure that the metal diffuser is in contact with only a dielectric the thermal conductivity of which is relatively low. Therefore, a problem that when a part of recording energy is absorbed by the metal diffuser, the temperature rapidly rises, the metal diffuser is gradually oxidized, a function as the diffuser is damaged and in the worst case, the diffuser is dissolved and broken exists. Therefore, it is required that incident light from the light source can be converted to an optical near field at higher efficiency. Besides generally, as a dielectric and metal forming the diffuser are greatly different in a coefficient of thermal expansion, great stress is caused on an interface between both, and as possibility that the metal diffuser may peel and fall from the dielectric is high, the realization of a reliable recording head and a reliable information recording apparatus is hindered.
Besides, in case the similar thermomagnetic recording to a current magneto-optical disk is applied to a perpendicular magnetic recording medium advantageous in high-density magnetic recording using the second and third prior arts, the transition width of magnetization in the magnetic recording layer is determined by only a temperature gradient on the recording medium in recording. Therefore, unless the distribution size of an optical near field is reduced, the transition width of magnetization cannot be reduced and there is a limit to increase recording density without increasing the manufacuring precision of the metal diffuser.

Recording head and information recording apparatus


A spectacle frame mount provides secure, removable positioning of a spectacle frame in a gas mask or full face respirator. A spring wire mount supports the spectacle frame between two legs of a loop. The spring wire mount includes two leg portions that have lower ends which terminate adjacent each other when the mount is in its use position. The two leg portions positively engage an internal portion of the full face mask so that the spectacle frame will be positioned within the interior of the mask at a location such that the spectacles will be properly positioned for use by the person wearing the mask.

It is quite common in a number of situations for a person to be required to wear a gas mask or full face respirator. Firefighters, chemical workers, police officers in certain situations, hazardous material disposal personnel and the like are only a few examples of the wide range of people who must wear a full face respirator or gas mask during at least a portion of their working day. Such full face respirators or gas masks typically include a wraparound clear plastic lens that is supported in a soft, pliable silicone facepiece. While other styles of full face respirators and gas masks are available on the market, the typical configuration is as described above.
A substantial number of the people whose work environment requires the use of such a full face respirator or gas mask are also required to wear some type of corrective lenses because of visual limitations. In a normal situation, such as in a non-hazardous environment, many of these visually challenged workers would rely on contact lenses or on eyeglasses which are provided with generally well-known side pieces.
Many people however, cannot wear contact lenses for a variety of reasons. As a result, many users of full face respirators or gas masks often do not use contact lenses when they are wearing these full face masks. Instead, they rely on more conventional spectacles.
A full face mask will typically have its soft, pliable facepiece, fabricated of silicon or the like, define a seal around the wearer's eyes, nose and mouth. That seal typically depends on a positive contact between the soft, pliable material of the facepiece and the skin of the wearers. Facial hair, such as a beard, is apt to compromise the ability of the facepiece to form a positive, leakproof seal. For that reason, most full face masks do not cover the wearer's ears. To do so would require, on most wearers, that a seal be made against the wearer's scalp which is typically covered with hair.
As is well known, conventional eyeglasses include side pieces that extend from the lens frame of the eyeglasses, across the temples of the wearer and which attach about the wearer's ears. These side pieces would thus have to pass under the edge of the facepiece and would therefor compromise the seal integrity of the facepiece.
The assignee of the subject application, Mine Safety Appliances Company ("MSA"), of Pittsburgh, Pa., is a supplier of a large number of full face respirators and gas masks. They are also the assignee of U.S. Pat. No. 3,563,640, which is directed to a device for holding spectacles in a mask. That patented device has been commercialized in an MSA Spectacle Kit which has been widely sold and used. As may be seen in that patent, the device for holding spectacles is a mount including a spring wire with a central downwardly extending loop that supports a friction member. The friction member is configured to support a spectacle frame and the spring wire is adapted to be secured in a channel or groove that defines the juncture between the wraparound lens and the facepiece.
While this prior MSA device has enjoyed substantial commercial success, it has been determined that the prior spectacle holding device does not provide as much stability, in the mounting of the eyeglasses, as may be required for certain use applications. A number of wearers of full face masks engage in rather strenuous activities. Firefighters are a group of users of full face respirators or gas masks who, in the course of their occupational activities, engage in running, jumping and other similar activities where it is imperative that the spectacle holding and mounting device must be able to retain the spectacles in their intended position. Lenses for eyeglasses are ground based on a distance from the lens to the user's eye. If that distance varies by too great an amount, the user's vision is impaired. Eyeglass lenses are also ground or formed so that their optical centers will be aligned with the wearer's pupils. If the eyeglasses shift or are dislodged, so that the optimum alignment is compromised, the vision of the user will again be degraded.
It will thus be appreciated that there is a need for improved devices for holding eyeglasses or spectacles in a full face respirator or gas mask. The spectacle frame mount, in accordance with the present invention, overcomes the limitations of the known devices and is a substantial advance in the art.


A semiconductor processing apparatus including a processing chamber and a plurality of radiant heat sources. The radiant heat sources heat a workpiece within the chamber. At least one of the radiant heat sources is movable during processing in an oscillatory motion along a path less than about 10 mm from a geometric center of the oscillatory motion.

1. Field of the Invention
The invention generally relates to heating systems for semiconductor manufacturing equipment. More specifically, the invention relates to radiant heat sources for improving temperature uniformity.
2. Description of the Related Art
Chemical vapor deposition (CVD) is a very well known process in the semiconductor industry for forming thin films of materials on wafers. In a CVD process, gaseous molecules of the material to be deposited are supplied to wafers to form a thin film of that material on the wafers by chemical reaction. Such formed thin films may be polycrystalline, amorphous, or epitaxial. Typically, CVD processes are conducted at elevated temperatures in order to accelerate the chemical reaction.
In the semiconductor industry, it is important that the material be deposited with uniform properties, such as thickness and composition, over the wafer. In Very Large and Ultra Large Scale Integrated Circuit (VLSI and ULSI) technologies, the wafer is divided into individual chips having integrated circuits thereon. If a CVD process step produces deposited layers with non-uniformities, devices at different areas on the wafer and even devices within the chips may have inconsistent operation characteristics, or may fail altogether.
Various process parameters must be carefully controlled to ensure the high uniformity of the resulting layers. One such parameter is the temperature of the wafer or other substrate during certain steps. During CVD, for example, the deposition gases react at particular temperatures and deposit on the wafer. If the temperature varies across the surface of the substrate, uneven deposition of the reactant gas occurs and the thickness and resistivity will not be uniform. Other fabrication techniques, such as etching and annealing, also depend upon uniform temperature distribution across the substrate(s). Accordingly, it is desirable that temperature be uniform across the substrate.
Substrates can be heated using resistance heating, induction heating, or radiant heating. Among these, radiant heating is currently the favored method of supplying heat energy to a wafer in a single wafer processing chamber. Significantly, radiant heating results in short processing times and high throughput because the temperature of the wafers can be ramped up to the desired process temperature and ramped down to a satisfactory handling temperature faster than with the alternative heating techniques. Additionally, radiant heating can be controlled to maintain the wafer at the desired temperature for a sufficient duration to accomplish the process. Radiant heating energy can be supplied, for example, by banks of infrared (IR) lamps (e.g., quartz halogen lamps) above and/or below the wafer in the reaction chamber.
Radiant energy has a tendency to create non-uniform temperature distributions, including areas of less intensity (or shadows or "cold spots") and areas of more intensity (or "hot spots") due to the use of localized lamps and the consequent focusing and interference effects. In an effort to provide more uniform heat source distribution and a resulting uniform temperature distribution across the wafers, the industry practice has been to mount reflectors behind the bulbs to reflect the energy from the bulbs and direct the same onto the wafers. These reflectors are generally made of a base metal and are plated to efficiently reflect the light energy. However, radiant heat sources still tend to induce hot and cold spots on wafers being heated.
Temperature non-uniformities may be somewhat reduced by rotating the wafer during processing. Continuous rotation about a vertical axis about perpendicular to the wafer moves regions of the wafer that would otherwise reside within shadows or hot spots to distribute temperatures on the wafer surface somewhat more uniformly. Temperature non-uniformities may also be somewhat reduced by continuously rotating the reflector about a vertical axis as disclosed in U.S. Pat. No. 6,554,905. However, it has been found that temperature uniformity suffers even with this continual rotation of the wafer or the reflector bank about a vertical axis. Specifically, hot and cold spots remain in the form of rings at particular radial distances from the center, or in regions on the wafer surface.


A marker pattern for enhancing resolution of a defect location along an axis in semiconductor defect analysis, and in particular, a marker pattern providing greater resolution in locating bit line defects using thermal laser stimulation methods such as OBIRCH. In an example, the marker pattern may consist of large markers, each having a set of associated small markers. Each of the small markers may be offset along an axis from each other. By identifying the small marker and its associated large marker which align with the defect, the bit line containing the defect may be more easily identified.

The strong growth in demand for portable consumer electronics is driving the need for high-capacity storage devices. Non-volatile semiconductor memory devices, such as flash memory storage cards, are becoming widely used to meet the ever-growing demands on digital information storage and exchange. Their portability, versatility and rugged design, along with their high reliability and large capacity, have made such memory devices ideal for use in a wide variety of electronic devices, including for example digital cameras, digital music players, video game consoles, PDAs and cellular telephones.
As semiconductor manufacturing processes become more miniaturized and complex, the causes for failure within semiconductor die are also becoming more complex. Depending on the nature of failure modes, various non-destructive methods may be used to locate defects, such as for example current time domain reflectometry (CTDR), infrared imaging technology, scanning acoustic microscopy (SAM), and x-ray computed tomography. More recently, thermal laser stimulation methods such as optical beam induced resistance change (OBIRCH) have been used in addition to or instead of some of the above methods. Failure analysis by OBIRCH involves scanning metal lines of an integrated circuit (IC) with a laser in the infrared region. The laser locally heats the metal lines. Areas of the metal lines containing a defect will heat differently than normal areas, resulting in resistance changes in those defect areas. By applying a constant voltage, areas having resistance changes will result in current changes, which can in turn be plotted in a brightness image, where areas of different current show up as "hot spots" of different pixel brightness. The brightness image can be overlaid onto the IC drawing so that areas on the IC which have defects show up as hot spots.
One problem is that the resolution of OBIRCH is around 5 μm, owing for example to the infrared wavelength of the laser. As the bit line pitch is on the order of 50 nanometers, conventional OBIRCH methods do not provide sufficient resolution with respect to the bit line defect location.

Marker pattern for enhanced failure analysis resolution


An adaptive signal processing system for improving a quality of a signal. The system includes an analysis filterbank for transforming a primary information signal in time domain into oversampled sub-band primary signals in frequency domain and an analysis filterbank for transforming a reference signal in time domain into oversampled sub-band reference signals. Sub-band processing circuits process the signals output from the filterbanks to improve a quality of an output signal. A synthesis filterbank can combine the outputs of the sub-band processing circuits to generate the output signal.

A conventional approach in the signal processing applications listed above is to use a time domain approach, where a filterbank is not used, and a single adaptive filter acts on the entire frequency band of interest. This single time domain filter is typically required to be very long, especially when applied to acoustic echo cancellation. Computational requirements are a concern because longer filters require exponentially increasingly more processing power (i.e., doubling the filter length increases the processing requirements by more than two). A longer filter typically requires more iterations by its adaptive controlling algorithm to converge to its desired state. In the case of an adaptive noise cancellation algorithm, slow convergence hampers the ability of the system to quickly reduce noise upon activation and to track changes in the noise environment.
In summary, the problems with time domain adaptive signal processing are: 1) Long filters are required—cannot interleave the update of multiple filters. 2) Slower filter convergence due to longer filter length, 3) Performance problems in the presence of coloured noise, and 4) Inability to set varying algorithm parameters for individual frequency bands.
Solutions to problems in time domain adaptive signal processing arising from coloured noise and a long filter are limited. A long filter is often a requirement that is dictated by the particular application, and shortening it would degrade performance. In cases when it is allowable, white noise can be inserted into the signal path to allow the filter to adapt quicker.
Slow convergence is usually dealt with by choosing algorithm parameters that result in fast convergence while still guaranteeing filter stability. In the Least Mean Squares (LMS) algorithm this is done by increasing the step-size parameter (mu). However, this approach causes considerable distortion in the processed output signal due to the larger fluctuations of the adaptive filter resulting from a high mu value.
A method used to increase computational speed in time domain signal processing is to perform operations in the Fourier transform domain (see J. J. Shynk, "Frequency Domain and Multirate Adaptive Filtering", IEEE Signal Processing Magazine, vol. 9, no. 1, pp. 15–37 January 1992). A section of the signal is transformed, operated on, then undergoes an inverse transformation. Methods are well known for performing specific operations in the transform domain that directly correspond to linear convolution (a common operation) in the time domain, but require less processing time. The added requirement of having to calculate the Fourier transform and inverse Fourier transform is offset when the signal can be transformed in blocks that are sufficiently large.

Sub-band adaptive signal processing in an oversampled filterbank


A photoconductive imaging member comprised of a supporting substrate, and thereover a single layer comprised of a mixture of a photogenerator component, charge transport components, and a certain electron transport component, and a certain polymer binder.

This invention relates in general to electrophotographic imaging members, and more specifically, to positively and negatively, preferably positively charged electrophotographic imaging members with a single electrophotographic photoconductive insulating layer and processes for forming images on the member. More specifically, the present invention relates to a single layered photoconductive imaging member useful in electrostatic digital, including color, process, and which members contain a charge generation layer or photogenerating layer comprised of a photogenerating component, such as a photogenerating pigment, dispersed in a matrix of a hole transporting and an electron transporting binder, and in embodiments a protective overcoat, such as a polymer layer. The electrophotographic imaging member layer components, which can be dispersed in various suitable resin binders, can be of various thicknesses, however, in embodiments a thick layer, such as from about 5 to about 60, and more specifically, from about 10 to about 40 microns, and yet more specifically, from about 15 to about 40 microns, is selected. This layer can be considered a dual function layer since it can generate charge and transport charge over a wide distance, such as a distance of at least about 50 microns. Also, the presence of the electron transport components in the photogenerating layer can enhance electron mobility and thus enable a thicker photogenerating layer, and which thick layers can be more easily coated than a thin layer, such as about 1 to about 2 microns thick.
The expression "single electrophotographic photoconductive insulating layer" refers in embodiments to a single electrophotographically active photogenerating layer capable of retaining an electrostatic charge in the dark during electrostatic charging, imagewise exposure and image development. Thus, unlike a single electrophotographic photoconductive insulating layer photoreceptor, a multi-layered photoreceptor has at least two electrophotographically active layers, namely at least one charge generating layer and at least one separate charge transport layer.
A number of known electrophotographic imaging members are comprised of a plurality of other layers such as a charge generating layer and a charge transport layer. These multi-layered imaging members in some instances also can contain a charge blocking layer and an adhesive layer between the substrate and the charge generating layer. Further, an anti-plywood layer may be included in the imaging member. Complex equipment and valuable factory floor space are usually needed to manufacture multi-layered imaging members. In addition to presenting plywooding problems, multi-layered imaging members often encounter charge spreading which degrades image resolution. The anti-plywood layer can be a separate layer or be part of a dual function layer. An example of a dual function layer for preventing plywooding is the use of a charge blocking layer or an adhesive layer. The expression "plywood" refers, for example, to the formation of unwanted patterns in electrostatic latent images caused by multiple reflections during laser exposure of a charged imaging member. When developed, these patterns resemble plywood. Multi-layered imaging members are also costly and time consuming to fabricate because of the many layers that need to be formed.
Another problem encountered with multilayered photoreceptors comprising a charge generating layer and a charge transport layer is that the thickness of the charge transport layer, which is normally the outermost layer, tends to become thinner due to wear during image cycling. The change in thickness can cause changes in the photoelectrical properties of the photoreceptor. Thus, to maintain image quality, complex and sophisticated electronic equipment and software management are usually encountered in the imaging machine to compensate for the photoelectrical changes, which can increase the complexity of the machine, the cost of the machine, the size of the footprint occupied by the machine, and the like. Without proper compensation of the changing electrical properties of the photoreceptor during cycling, the quality of the images formed can degrade because of spreading of the charge pattern on the surface of the imaging member and a decline in image resolution. High quality images can be important for digital copiers, duplicators, printers, and facsimile machines, particularly laser exposure machines that demand high resolution images. Moreover, the use of lasers to expose conventional multilayered photoreceptors can lead to the formation of undesirable plywood patterns that are visible in the final images.
Attempts have been made to fabricate electrophotographic imaging members comprising a substrate and a single electrophotographic photoconductive insulating layer in place of a plurality of layers such as a charge generating layer and a charge transport layer. However, in formulating single electrophotographic photoconductive insulating layer photoreceptors many problems need to be overcome including acceptable charge acceptance for hole and/or electron transporting materials from photoelectroactive pigments. In addition to electrical compatibility and performance, a material mix for forming a single layer photoreceptor should possess the proper rheology and resistance to agglomeration to enable acceptable coatings. Also, compatibility among pigment, hole and electron transport molecules, and film forming binder is desirable.

This patent is subject to a terminal disclaimer.


A digital signal processor configured to perform a Viterbi algorithm includes an instruction fetching unit that fetches instructions and a decoding unit that decodes the instructions fetched by the instruction fetching unit. The digital signal processor also includes an execution unit that executes the instructions decoded by the decoding unit. The execution unit includes an arithmetic logic unit configured to perform a register—register arithmetic logic operation. The arithmetic logic unit compares a first data with a second data, in parallel with a comparison of a third data with a fourth data, and the execution unit outputs new path metrics. Each of the first data, the second data, the third data, and the fourth data is one of four results obtained by adding one of two path metrics to one of two branch metrics.

1. Field of the Invention
The present invention relates to a processing unit, which is incorporated into a mobile communication apparatus, for performing an ASC (Addition, Comparison, and Selection) operation of particularly a Viterbi decoding.
2. Background Information
In data communications in a mobile radio communication network, since a bit error frequently occurs, an execution of an error correction processing is needed. In the error correction methods, there is a method in which a convolutional code generated from an input bit is decoded by Viterbi decoding on a receiver side. In the error correction processing, a digital signal processor (hereinafter referred to as "DSP") is used.
The Viterbi decoding repeats the simple processing such as addition, comparison, and selection and performs a trace-back operation for finally data, thereby realizing a maximum likelihood decoding of the convolutional code.
The following will briefly explain the Viterbi decoding processing. The convolutional code is generated by mode 2 addition of input bits and a fixed number of bits precedent thereto. Then, a plurality of coding data is generated to correspond to one bit of the input bits. A number of input information bits having influence upon the coding data is called constraint length (K). The number of input information bits is equal to a number of stages of shift registers used in mode 2 addition.
The coding data is determined by the input bits and a state of the preceding (K−1) input bits. When a new information bit is input, the state of the input bits transits to a new state. The state in which coding data transits is determined by whether the new input bit is "0" or "1." Since the respective (K−1) bits are "1" or "0", a number of states in which coding data transits becomes 2(K−1).
In the Viterbi decoding, received coding data sequence is observed, and the most-likely state is estimated from all obtainable state transitions. For this reason, every time when coding data (received data sequence) corresponding to one bit of information bits, an inter-signal distance (metric) of the respective paths to each state at that point is computed. Then, operations for leaving a path having a smaller metric among the paths reaching the same state as a survivor are sequentially repeated.
As shown in a state transition diagram of FIG. 1, in a convolutional encoder having a constraint length K, two paths each showing a state transition from each of state S[n] and S[n+2(K−2)] at one previous point extend to a state S[2n] (n=positive integer) at a certain point. For example, in a case of K=3, a transition from each of S[1] (state S01) and S[3] (state S11) to S[2] (state S10) (state in which preceding two bits are input in order of "1" and "0") at the time of n=1 is possible. Also, at the time of n=2, a transition from each of S[2] (state S10) and S[4] (state S00) to S[4] (state S00)(state shown by low-order two bits) is possible.
A path metric "a" is a sum of an inter-signal distance (branch metric) "x" between an output symbol of the path inputting to the state S[2n] and the received data sequence and a path metric "A." The path metric "A" is the total sum of branch metrics of the survivor paths up to the state S[n] at one previous state. Similarly, a path metric "b" is a sum of an inter-signal distance (branch metric) "y" between an output symbol of the path inputting to the state S[2n] and the received data sequence and a path metric "B." The path metric "B" is the total sum of branch metrics of the survivor paths up to the state S[n+2(K−2)] at one previous point. In the Viterbi decoding, the path metrics "a" and "b" inputting to the state S[2n] are compared with each other, and the smaller path is selected as a survivor path.
In the Viterbi decoding, each processing of addition for obtaining the path metric, comparison between the path metrics and the selection of path is executed with respect to 2(K−2) states at each point. Moreover, in the selection of path, a history showing which path has been selected is left as a path select signal PS[i], [I=0 to 2(K−2)−1].
At this time, if a subscript (e.g., n) of one previous state of the selected path is smaller than a subscript (n+2(K−2)) of one previous state of the non-selected other path, PS[i]=0 is established. If the subscript (n) it is larger than the subscript (n+2(K−2)), PS[i]=1 is established.
In the case of FIG. 1, since n<(n+2(K−2)) is established, the state S[n+2(K−2)] is selected at the time of a>b and PS[S2n]=1 is established, and the state S[n] is selected at the time of a≦b and PS[S2n]=0 is established.
Then, in the Viterbi decoding, data is decoded while being traced back to the path finally survived based on the path select signal.
The following will explain the conventional processing unit for Viterbi decoding, TMS320C54x, which is a general processing unit, (manufactured by TEXAS INSTRUMENTS, hereinafter referred to as "C54x") being given as one example. In a GSM cellular radio system, equation (1) set forth below is used as a convolutional code.G1(D)=1+D3+D4G2(D)=1+D+D3+D4  (1)
The above convolutional code is expressed by a trellis diagram of a butterfly structure shown in FIG. 2. The trellis diagram shows a state in which the convolutional code transits from a certain state to another state. Let us assume that constraint length K is 5. States of 2(K−2)=16 or 8 butterfly structures are present for each symbol section. Then, two branches are input in each state, and a new path metric is determined by the ACS operations.
The branch metric can be defined as the following equation (2).M=SD(2*i)*B(J,0)+SD(2*i+1)*B(j,1)  (2)where SD(2*i) denotes a first symbol of a symbol metric showing a soft decision input, and SD(2*i+1) denotes a second symbol of the symbol metric. B(J,0) and B(j,1) conform to codes generated by a convolutional encoder as shown in FIG. 3.
In C54x, an arithmetic logic section (hereinafter referred to as "ALU") is set to a dual 16-bit mode, thereby processing the butterfly structure at high speed. The determination of a new path metric (j) can be obtained by calculating two path metrics (2*J and 2*J+1) and the branch metrics (M and −M) in parallel based on a DSADT instruction and executing a comparison based on a CMPS instruction. The determination of a new path metric (j+8) can be obtained by calculating two path metrics and the branch metrics (M and −M) in parallel based on the DSADT instruction. The calculation results are stored in high and low order bits of a double-precision accumulator, respectively.
The CMPS instruction compares the high and low order bits of the accumulator and stores a larger value in a memory. Also, every time when the comparison is executed, which value is selected is written in a 16-bit transition register (TRN). The content written to the TRN is stored in the memory every time when each symbol processing is ended. Information to be stored in the memory is used to search a suitable path in the trace-back processing. FIG. 4 shows a macro program for a butterfly operation of the Viterbi decoding.
The values of the branch metrics are stored in the T register before the macro is called. FIG. 5 shows an example of a memory mapping of the path metrics.
8 butterfly operations are executed in one symbol section and 16 new states are obtained. This series of processing is repeatedly computed over several sections. After the end of the processing, the trace-back is executed so as to search a suitable path from 16 paths. Thereby, a decoding bit sequence can be obtained.
The mechanism of the ACS operations of the C54x, which is the general DSP, can be thus explained. Then, in C54x, and the updates of two path metrics are realized with 4 machine cycles from the example of the macro program of FIG. 4.
In the future, there is expected an increase in demand for non-voice communications requiring high quality transmission with a lower bit error rate than voice communications. As means for achieving the low bit error rate, there is means for increasing the constraint length K of the Viterbi decoding.
However, if the constraint length is increased by a value corresponding to one bit, a number of path metrics (number of states) doubles. For this reason, a number of operations in the Viterbi decoding using DSP double. Generally, an amount of information in non-voice communications is larger than the amount of information in voice communications. If the amount of information increases, the number of operations in the Viterbi decoding including the ACS operation also increases. An increase in number of operations using DSP makes it difficult to maintain a battery for a portable terminal for a long period of time.
For the purpose of downsizing the portable terminal, reducing the weight, and lowering the cost, an area processed by a special LSI has been also designed to be implemented in one chip form using a DSP processing in recent years.
However, an increase in the number of operations using DSP exceeds the processing capability of the existing DSP, thereby making it impossible to be implemented in one chip form using DSP.
Moreover, if the function of DSP is highly enhanced to increase the number of operations, an increase in the cost of DSP itself is brought about. As a result, the reduction in the cost of the portable terminal cannot be realized.
A first object of the present invention is to provide a processing unit for efficiently processing an ACS operation of the Viterbi decoding by use of DSP with a small investment in software. The above object can be attained by arranging two pairs of comparing sections, an adding section, and a storing section for storing a comparison result in the processing unit and by executing the ACS operation in parallel.

Matsushita Electric Industrial Co., Ltd.


A method and apparatus is provided for estimating signal power. The estimating is accomplished by correlating (206) an input data vector (204) with a set of mutually orthogonal codes to generate a set of output values. The input data vector (204) consists of data samples of a received orthogonal coded signal (202). Each output value corresponds to a measure of confidence that the input data vector is substantially similar to one of the orthogonal codes from within the set of mutually orthogonal codes. Finally, an estimate of the power of the received orthogonal coded signal is generated (208) as a nonlinear function of the set output values.

Communication systems take many forms. In general, the purpose of a communication system is to transmit information-bearing signals from a source, located at one point, to a user destination, located at another point some distance away. A communication system generally consists of three basic components: transmitter, channel, and receiver. The transmitter has the function of processing the message signal into a form suitable for transmission over the channel. This processing of the message signal is referred to as a modulation. The function of the channel is to provide a physical connection between the transmitter output and the receiver input. The function of the receiver is to process the received signal so as to produce an estimate of the original message signal. This processing of the received signal is referred to as demodulation.
Two types of two-way communication channels exist, namely, point-to-point channels and point-to-multipoint channels. Examples of point-to-point channels include wirelines (e.g., local telephone transmission), microwave links, and optical fibers. In contrast, point-to-multipoint channels provide a capability where many receiving stations may be reached simultaneously from a single transmitter (e.g. cellular radio telephone communication systems). These point-to-multipoint systems are also termed Multiple Address Systems (MAS).
Analog and digital transmission methods are used to transmit a message signal over a communication channel. The use of digital methods offers several operational advantages over analog methods, including but not limited to: increased immunity to channel noise and interference, flexible operation of the system, common format for the transmission of different kinds of message signals, improved security of communication through the use of encryption, and increased capacity.
These advantages are attained at the cost of increased system complexity. However, through the use of very large-scale integration (VLSI) technology a cost-effective way of building the hardware has been developed.
To transmit a message signal (either analog or digital) over a band-pass communication channel, the message signal must be manipulated into a form suitable for efficient transmission over the channel. Modification of the message signal is achieved by means of a process termed modulation. This process involves varying some parameter of a carrier wave in accordance with the message signal in such a way that the spectrum of the modulated wave matches the assigned channel bandwidth. Correspondingly, the receiver is required to recreate the original message signal from a degraded version of the transmitted signal after propagation through the channel. The re-creation is accomplished by using a process known as demodulation, which is the inverse of the modulation process used in the transmitter.
In addition to providing efficient transmission, there are other reasons for performing modulation. In particular, the use of modulation permits multiplexing, that is, the simultaneous transmission of signals from several message sources over a common channel. Also, modulation may be used to convert the message signal inot a form less susceptible to noise and interference.
For multiplexed communication systems, the system typically consists of many remote units (i.e. subscriber units) which require active service over a communication channel for a short or discrete portion of the communication channel resource rather than continuous use of the resources on a communication channel. Therefore, communication systems have been designed to incorporate the characteristic of communicating with many remote units for brief intervals on the same communication channel. These systems are termed multiple access communication systems.
One type of multiple access communication system is a spread spectrum system. In a spread spectrum system, a modulation technique is utilized in which a transmitted signal is spread over a wide frequency band within the communication channel. The frequency band is much wider than the minimum bandwidth required to transmit the information being sent. A voice signal, for example, can be sent with amplitude modulation (AM) in a bandwidth only twice that of the information itself. Other forms of modulation, such as low deviation frequency modulation (FM) or single sideband AM, also permit information to be transmitted in a bandwidth comparable to the bandwidth of the information itself. However, in a spread spectrum system, the modulation of a signal to be transmitted often includes taking a baseband signal (e.g., a voice channel) with the bandwidth of only a few kilohertz, and distributing the signal to be transmitted over a frequency band that may be many megahertz wide. This is accomplished by modulating the signal to be transmitted with the information to be sent and with a wideband encoding signal.
Three general types of spread spectrum communication techniques exist, including:
Direct Sequence
The modulation of a carrier by a digital code sequence whose bit rate is much higher than the information signal bandwidth. Such systems are referred to as "direct sequence" modulated systems.
Hopping
Carrier frequency shifting in discrete increments in a pattern dictated by a code sequence. These systems are called "frequency hoppers." The transmitter jumps from frquency to frequency within some predetermined set; the order of frequency usage is determined by a code sequence. Similarly "time hopping" and "time-frequency hopping" have times of transmission which are regulated by a code sequence.
Chirp
Pulse-FM or "chirp" modulation in which a carrier is swept over a wide band during a given pulse interval.
Information (i.e. the message signal) can be embedded in the spread spectrum signal by several methods. One method is to add the information to the spreading code before it is used for spreading modulation. This technique can be used in direct sequence and frequency hopping systems. It will be noted that the information being sent must be in a digital form prior to adding it to the spreading code, because the combination of the spreading code and the information typically a binary code involves module-2 addition. Alternatively, the information or message signal may be used to modulate a carrier before spreading it.
Thus, a spread spectrum system must have two properties: (1) the transmitted bandwidth should be much greater than the bandwidth or rate of the information being sent and (2) some function other than the information being sent is employed to determine the resulting modulated channel bandwidth.
Spread spectrum communication systems can be multiple access systems communication systems. One type of multiple access spread spectrum system is a code division multiple access (CDMA) system. In a CDMA system, communication between two communication units is accomplished by spreading each transmitted signal over the frequency band of the communication channel with a unique user spreading code. As a result, transmitted signals are in the same frequency band of the communication channel and are separated only by unique user spreading codes. These unique user spreading codes preferably are orthogonal to one another such that the cross-correlation between the spreading codes is approximately zero. CDMA systems may use direct sequence or frequency hopping spreading techniques. Particular transmitted signals can be retrieved from the communication channel by despreading a signal representative of the sum of signals in the communication channel with a user spreading code related to the particular transmitted signal which is to be retrieved from the communication channel. Further, when the user spreading codes are orthogonal to one another, the received signal can be correlated with a particular user spreading code such that only the desired user signal related to the particular spreading code is enhanced while the other signals for all of the other users are not enhanced.
It will be appreciated by those skilled in the art that several different spreading codes exist which can be used to separate data signals from one another in a CDMA communication system. These spreading codes include but are not limited to pseudonoise (PN) codes and Walsh codes. A Walsh code corresponds to a single row or column of the Hadamard matrix. For example, in a 64 channel CDMA spread spectrum system, particular mutually orthogonal Walsh codes can be selected from the set of 64 Walsh codes within a 64 by 64 Hadamard matrix. Also, a particular data signal can be separated from the other data signals by using a particular Walsh code to spread the particular data signal.
Further it will be appreciated by those skilled in the art that spreading codes can be used to channel code data signals. The data signals are channel coded to improve performance of the communication system by enabling transmitted signals to better withstand the effects of various channel impairments, such as noise, fading, and jamming. Typically, channel coding reduces the probability of bit error, and/or reduces the required signal to noise ratio usually expressed as bit energy per noise density (E.sub.b /N.sub.0), to recover the signal at the cost of expending more bandwidth than would otherwise be necessary to transmit the data signal. For example, Walsh codes can be used to channel code a data signal prior to modulation of the data signal for subsequent transmission. Similarly PN spreading codes can be used to channel code a data signal.
A typical spread spectrum transmission involves expanding the bandwidth of an information signal, transmitting the expanded signal and recovering the desired information signal by remapping the received spread spectrum into the original information signals bandwidth. This series of bandwidth trades used in spread spectrum signaling techniques allows a communication system to deliver a relatively error-free information signal in a noisy signal environment or communication channel. The quality of recovery of the transmitted information signal from the communication channel is measured by the error rate (i.e., the number of errors in the recovery of the transmitted signal over a particular time span or received bit span) for some E.sub.b /N.sub.0. As the error rate increases the quality of the signal received by the receiving party decreases. As a result, communication systems typically are designed to limit the error rate to an upper bound or maximum so that the degradation in the quality of the received signal is limited.
In CDMA spread spectrum communication systems, the error rate is related to the noise interference level in the communication channel which is directly related to number of simultaneous but code divided users within the communication channel. Thus, in order to limit the maximum error rate, the number of simultaneous code divided users in the communication channel is limited. However, the error rate is also affected by the received signal power level. In some spread spectrum communication systems (e.g., cellular systems) a central communication site typically attempts detect or receive more than one signal from a particular band of the electromagnetic frequency spectrum. The central communication site adjusts the receiver components to optimally receive signals at a particular received signal power threshold value. Those received signals having a received signal power level at or near the particular power threshold level are optimally received. While those received signals not having a received signal power level at or near the particular power threshold level are not optimally received. A non-optimally received signal tends to have a higher error rate or cause unnecessary interference to other receivers. Either of these undesirable consequences of a non-optimally received signal can result in the communication system further limiting the number of simultaneous users in the communication channel associated with the central communication site. Thus, it is desirable to maintain the received signal power level at or near the particular power threshold level. This can be accomplished by adjusting the signal power level of transmitters attempting to transmit to the central communication site. Therefore, by using power control schemes to maintain the received signal power levels at a particular power threshold level the number of simultaneous users in a communication channel can be maximized for a particular maximum error rate limit. However, a need exists for a more accurate received signal power level estimation scheme for use in CDMA spread spectrum communication systems. Through the use of a more accurate received signal power level estimation scheme, the number of simultaneous users in a communication channel can be increased over the number of simultaneous users in a communication channel using less accurate received signal power level estimation scheme while maintaining the same maximum error rate limit.

Method and apparatus for power estimation in an orthogonal coded communication system


An address translator of a first communication station transmits to a second communication station a transmission frame that is sent from a terminal in the first communication station to a terminal in the second communication station and includes the virtual private address of the terminal, after the address translator translates the virtual private address into a corresponding real private address, while it determines the global address of the second communication station based on the virtual private address and applies it to the frame. The address translator of the second communication station that received the frame sends a content of the transmission frame to the terminal indicated by the real private address included in the transmission frame.

1. Field of the Invention
This invention relates to an address access system and method thereof, and specifically to an address access system that allows for accessing a private address located on a remote station from a center station, and method thereof.
2. Description of the Related Art
Global addresses such as an IP address (a network address and host address) that is an address on the Internet are limited by the total number. This causes shortage of global addresses. In many cases, therefore, only one global address can be assigned to each station (hosts, for example station routers, etc.) to be accessed.
In order to address such a situation, a controlled side (hereinafter referred to as a remote station) that may be accessed from a controlling side (hereinafter referred to as a center station) has employed a private address, aside from global addresses, as an internal address. In particular, a private address is assigned to a segment (e.g. gateway) of the remote station, and Network Address Translation (NAT) is performed in a connecting router etc. at the remote station. In this case, the address translation constitutes a 1-to-n address translation because of the existence of n private addresses for each global address.
As described above, because the 1-to-n address translation is performed in many cases, an access (creation of a TCP session) from a remote station to a center station is possible, while usually the creation of a TCP session from the center station to the remote station often may not be possible.
In order to provide a bi-directional, transparent access, each port is mapped to the segment (port mapping) in the connecting router etc. where NAT is performed at a remote station. This allows for creating a TCP session from a center station. If a port cannot be mapped in the connecting router etc. by any reason, however, the creation of a TCP session may not be possible from a center station. The mapping of a port in the connecting router etc. also impairs the security of the segment because it can be connected to from the Internet. Although using a security filter for protection may be considered, the connecting router etc. may be subject to an excessive load. Furthermore, addition of any segment (e.g. gateway) in a remote station or modification of any address in private addresses makes its administration complicate because the mapping of a port mapping in the connecting router etc. (and the setting of the security filter, if any) must be changed.
Means such as a Virtual Private Network (VPN) with IPSec etc. also provides for a bidirectional communication between a remote station and a center station. Similarly to the aforementioned case, an access (creation of a VPN session) from a remote station to a center station is possible, while usually the creation of a VPN session from the center station to the remote station has not been possible.

Address access system and method thereof


The present invention relates to systems and methods for reducing fouling of a surface of an optically transparent element with a light source. According to one aspect, the invention is a system including an LED for emitting UV-C radiation, a mount for directing emitted UV-C radiation toward the optically transparent element, and control circuitry for driving the LED. The system may be used to remove a desired amount of biofilm.

The growth and feeding of biofouling organisms (e.g., forming a hard substrate community) inhibits the operational characteristics of industrial objects, such as lenses. Several approaches are used to address this problem, including using coatings. However, in many circumstances a coating will not work. For example, windows of a submerged precision optical instrument cannot be coated due to concerns with obstructing the clarity of the windows, thereby affecting the instrument's measurements. Another approach is to remove the organisms manually, e.g., by scrubbing wiping akin to a windshield wiper, but the use of mechanical components can increase the opportunities for failure and introduce additional complexity and cost into the system.
Maintaining an uncompromised visual connection through the window is particularly important in many communications systems. For example, scientists are deploying unmanned underwater vehicles (UUV) that, due to their mobility, can expand the reach of seafloor observatories. These UUVs typically carry sensors on-board and operate autonomously, carrying out pre-programmed missions. While certain types of UUVs are tethered by cable to the seafloor observatories, the tethered UUVs have a short range of motion and are limited by the length of the tether. Scientists are also deploying un-tethered UUVs which may be controlled wirelessly by an acoustic communication system or an optical communication system. Acoustic communication systems, however, tend to be limited by low bandwidth and high latency, and do not permit video or other high-rate data transfers.
Accordingly, there is a need to provide an antifouling device that prevents and/or removes organisms from a surface in a marine environment. There is also a need for such a device to remove the organisms from a window while maintaining the integrity of the window for accurate sensor readings and communications.

Marine environment antifouling system and methods


Disclosed are methods and compositions for cementing in a subterranean formation. A method comprises introducing a resin composition into a wellbore. The resin composition may comprise a resin, a napthol-based epoxy resin additive, and a hardening agent. The napthol-based epoxy resin additive may comprise two naphthalene functional groups and two epoxide functional groups.

Embodiments relate to epoxy resin additives for use in subterranean operations and, more particularly, to napthol-based epoxy resin additives for use with resin compositions and resin-cement composites as well as methods of using the resin additives in well cementing operations for subterranean formations.
In well operations, such as well construction and remedial cementing, cement compositions are commonly utilized. Cement compositions may be used in primary cementing operations whereby pipe strings, such as casing and liners, are cemented in wellbores. In a typical primary cementing operation, a cement composition may be pumped into an annulus between the exterior surface of the pipe string disposed therein and the walls of the wellbore (or a larger conduit in the wellbore). The cement composition may set in the annular space, thereby forming an annular sheath of hardened, substantially impermeable material (i.e., a cement sheath) that may support and position the pipe string in the wellbore and may bond the exterior surface of the pipe string to the wellbore walls (or the larger conduit). Amongst other things, the cement sheath surrounding the pipe string should function to prevent the migration of fluids in the annulus, as well as protect the pipe string from corrosion. Cement compositions also may be used in remedial cementing methods, such as in squeeze cementing for sealing voids in a pipe string, cement sheath, gravel pack, subterranean formation, and the like. Cement compositions may also be used in surface applications, for example, construction cementing.
Other types of compositions, including non-cementitious settable sealant compositions, such as resin-based sealants, may be used in the primary and/or remedial cementing operations described above. These compositions may be circulated through the well bore for use in any of the primary or remedial cementing operations used in the field. Additionally, resin compositions may be blended with traditional cement compositions to create resin-cement composites which may also be used in any type of primary or remedial cementing operation. Amongst the many uses for resins, applications in the oil and gas industry are unique in their demand for long resin pot life and controlled density.
It is well known that resins used in well cementing may only be used in formations where the bottomhole static temperature is lower than the glass transition temperature. For example, if resin compositions are deployed in formations where the bottomhole static temperature is greater than the glass transition temperature of the resin, the cured resin may have reduced compressive strength and decreased durability. Therefore, it may be difficult to use resin compositions in every operation site in which they may be desirable.
Resin fortifiers, such as methylenebisphosphonates are one attempted solution to this issue. However, the resin fortifiers may not form covalent bonds with the resin and thus their effectiveness may decrease over time. Another attempted solution is the use of epoxy resins with more than two epoxy groups. These resins form a denser epoxy network as compared to resins with two or less epoxy groups, however, they may also have high viscosities and short thickening times. As such, they may not be able to be successfully placed into subterranean formations.

Napthol-based epoxy resin additives for use in well cementing


An amphibious vehicle (32) having a transverse mid- or rear-mounted engine (12) arranged to drive rear road wheels (30) and/or through an axial transmission (37), a marine propulsion unit (38), in which the engine (12) is so mounted in relation to the transmission (37) to the marine propulsion unit (38) that the bottom (8) of the engine is below the axis (37) of the transmission. This ensures an advantageous metacentric height which is preferably between 370 and 180 mm.

Practical amphibious vehicles generally have their engines mounted either centrally or in the rear of the vehicle so as to ensure a 'nose up' attitude when under way in marine mode. One such example of this conformation is as shown and described in Japan se Patent Publication No 63-093607 (Mazda Motor Corp). This Mazda proposal is for an amphibious vehicle having a transverse rear mounted engine arranged to drive selectively rear road wheels and/or, through an axial transmission, a marine propulsion unit in this case a pump jet. More particularly the engine is mounted at least partly above the rear road wheel driving axles. The pump jet is driven by a shaft from a gearbox called a "transfer device". The transfer device is so designed to power front road wheels or the pump jet as required and is itself driven from the engine via a ring gear on a differential. The transfer device is mounted ahead of the engine. The result of this Mazda conformation is that it is necessary to mount the engine above the pump jet driveshaft. This shaft is in turn central to the marine pump jet, which must be mounted to provide adequate ground clearance at the tail of the vehicle to give an adequate ramp angle when the vehicle is in road mode. Consequently the centre of gravity of the vehicle is higher than it would be for an equivalent purely marine craft. Again because it is not possible to ballast an amphibious vehicle any increase in the height of the centre of gravity relative to the centre of buoyancy is significant when considering roll in marine mode for a vehicle with a low freeboard.
It is therefore an object of the present invention to reduce the height of the centre of gravity relative to the centre of buoyancy so as to increase the stability of the amphibious vehicle commensurate with adequate ground clearance.


A mounting system includes a plurality of mounting structures attached to a perimeter of the radio and having longitudinal apertures extending therethrough. The mounting system also includes a plurality of mounting brackets having a pair of hook shaped ends opposing one another in spaced apart relationship and being disposed in the longitudinal apertures. The mounting system further includes fasteners for fastening the mounting brackets to vehicle structure.

1. Field of the Invention
The present invention relates generally to a flexible mounting system for vehicle modules such as air conditioning and heater controls, radios, cassette players, and the like.
2. Description of the Related Art
Generally, vehicles such as automotive vehicles include a module such as a radio disposed in a cavity of an instrument or dash panel. Typically, the radio is mounted in the cavity by a mounting frame and bracket assembly. However, a specific mounting frame and bracket assembly must be constructed for radios of various sizes and types which is undesired.
Several attempts have been made to provide mounting assemblies to accommodate modules of various sizes and types. Examples of such mounting assemblies are disclosed in U.S. Pat. No. 4,738,420 to Angle et al. and U.S. Pat. No. 4,742,978 to Ponticelli. However, there is a need in the art to provide a modular, flexible mounting system for a vehicle radio or the like which allows a choice of where to place mounting brackets.

Flexible mounting system for a vehicle module


Providing electrical isolation between the chipset and the memory data is disclosed. The disclosure includes providing at least one buffer in a memory interface between a chipset and memory modules. Each memory module includes a plurality of memory ranks. The buffers allow the memory interface to be split into first and second sub-interfaces. The first sub-interface is between the chipset and the buffers. The second sub-interface is between the buffers and the memory modules. The method also includes interleaving output of the buffers, and configuring the buffers to properly latch the data being transferred between the chipset and the memory modules. The first and second sub-interfaces operate independently but in synchronization with each other.

The present disclosure relates to providing data buffers in an interface between a chipset and multiple ranks of memory modules.
Computer systems often contain one or more integrated circuit ("IC") chips, often called a chipset, that are coupled to memory modules via a memory interface. The memory interface provides communication between the IC chipset (e.g. the CPU) and the memory modules. The memory interface may contain address bus lines, command signal lines, and data bus lines. Increasing demand for higher computer performance and capacity has resulted in a demand for a larger and faster memory. However, as the operating speed and the number of memory modules connected to the chipset increase, the resulting increased capacitive loading may place a substantial limit on the amount and speed of memory.
Prior art designs, such as a registered dual in-line memory module (DIMM), have addressed the above-described difficulties by providing an address/command buffer in the address bus lines and the command signal lines to relieve the capacitive loading effects. Karabatsos (U.S. Pat. No. 5,953,215) describes a loading relief design for the data bus lines by providing FET switches in the interface between the chipset and the memory modules.
In the prior art design 100 of FIG. 1, the interface 108 between the chipset 102 and the memory modules 104 is unbuffered. In some embodiments, the memory modules 104 may be individually mounted on memory boards 106 as shown. In other embodiments, the memory modules 104 may be soldered directly onto the same motherboard as the chipset 102.
In the prior art design 100, the chipset 102 is often configured to receive two supply voltages, about 1.0 volt (low) and 1.5 volts (high). The high voltage is necessary on the chipset side to provide compatible driving voltage on the memory interface 108. Further, the pin count on the chipset 102 may be designed to be 2x in order to provide a particular memory access rate or frequency, such as ω.

Buffering and interleaving data transfer between a chipset and memory modules


A process for operating an electromagnetic actuator is provided, in particular to actuate a gas exchange lift valve of an internal combustion engine, with an armature, which is moved oscillatingly between two electromagnetic coils against the force of at least one return spring via an alternating supply of current to the electromagnetic coils. Whereby, during the so-called catch process as the armature approaches the coil that is subjected first to a current flow, the voltage applied to the coil catching the armature is reduced. To avoid unnecessary losses, a voltage curve is chosen with which an eddy current, calculated with a mathematical model, is minimized in the armature.

This application claims the priority of German Application No. 100 12 988.8, filed Mar. 16, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a process for operating an electromagnetic actuator and, more particularly, to a process for actuating a gas exchange lift valve of an internal combustion engine, with an armature, which is moved oscillatingly between two electromagnetic coils against the force of at least one return spring via an alternating supply of current to the electromagnetic coils.
A preferred application for an electromagnetic actuator of the type described above is for electromagnetically actuating a valve drive mechanism of an internal combustion engine. That is, the gas exchange lift valves of an internal combustion piston engine are actuated by such actuators in the desired manner, so as to be opened and closed in an oscillating manner. In such an electromechanical valve drive mechanism, the lift valves are moved individually (or also in groups) by means of electromechanical actuating elements - the so-called actuators - whereby the time for opening and closing each lift valve can be selected in essence arbitrarily. Thus, the valve timing of the internal combustion engine can be adjusted optimally to the current operating state (which is defined by the speed and the load) and to the respective requirements with respect to consumption, torque, emission, comfort and response characteristics of a motor vehicle, driven by the internal combustion engine.
The essential components of a known actuator for actuating the lift valves of an internal combustion engine are an armature and two electromagnets for holding the armature in the position xe2x80x9clift valve openxe2x80x9d or xe2x80x9clift valve closedxe2x80x9d with the related electromagnetic coils. Furthermore, return springs are provided for the movement of the armature between the position xe2x80x9clift valve openxe2x80x9d and xe2x80x9clift valve closedxe2x80x9d. In this respect reference is also made to the attached FIG. 1, which depicts such an actuator with a related lift valve in the two possible end positions of the lift valve and the actuator-armature. Between the two illustrated states or positions of the actuator lift valve unit, diagrams illustrate the curve of the armature lift z or the armature path between the two electromagnetic coils and, furthermore, the current flow I in the two electromagnetic coils over time t in accordance with the known state of the art (which is simpler than the mechanism described in German Patent document DE 195 30 121 Al, discussed in the introductory part of the specification).
FIG. 1 depicts the closing operation of an internal combustion engine lift valve, which is marked with the reference numeral 1. As usual, a valve closing spring 2a acts on the lift valve 1. Furthermore, the actuator, which is generally designated by reference numeral 4 in its entirety, acts on the shaft of the lift valve 1 - here with intercalation of a hydraulic valve play compensating element 3 (which is not absolutely necessary). The actuator 4 comprises not only two electromagnetic coils 4a, 4b, but also a push rod 4c, which acts on the shaft of the lift valve 1 and which bears an armature 4d. The armature 4d can be slid longitudinally and oscillatingly between the electromagnetic coils 4a, 4b. Furthermore, a valve opening spring 2b acts on the end of the push rod 4c, facing away from the shaft of the lift valve 1.
Thus, FIG. 1 depicts an oscillatory system, for which the valve closing spring 2a and the valve opening spring 2b form a first and a second return spring, for which consequently the reference numerals 2a, 2b are also used.
The first end position of this oscillatory system is shown on the left hand side of FIG. 1, where the lift valve 1 is completely open and the armature 4d rests against the bottom electromagnetic coil 4b. This coil 4b is also called hereinafter the opener coil 4b, since it holds the lift valve 1 in its opened position.
The second end position of the oscillatory system is shown on the right hand side of FIG. 1, where the lift valve 1 is completely closed and the armature 4d rests against the upper electromagnetic coil 4a. This coil 4a is also called hereinafter the closer coil 4a, since it holds the lift valve 1 in its closed position.
At this point, the closing operation of the lift valve 1 will now be described, that is, in FIG. 1 the transition from the open state, illustrated on the left hand side, into the closed state, illustrated on the right hand side. Between the two sides the corresponding curves of the electrical currents I, flowing into the coils 4a, 4b, and the lift curve or the path coordinate z of the armature 4d are plotted, respectively, over time t.
Starting from the left-hand side position xe2x80x9clift valve openxe2x80x9d, the supply of current is guided first to the opener coil 4b so that the armature 4d pushes in this position against the stressed valve closing spring 2a (=bottom first return spring 2a), whereby the current I in this coil 4b is shown with a dashed line in the I-t diagram. If at this stage the current I of the opener coil 4b is turned off for a desired transition to xe2x80x9clift valve closedxe2x80x9d, the armature 4d detaches from this coil 4b and the lift valve 1 is accelerated by means of the stressed valve closing spring 2a into approximately its central position (in the direction toward the top of the page), but then continues to move owing to its mass inertia so as to thereby stress the valve opening spring 2b, so that the lift valve 1 (and the armature 4d) are decelerated. Then, at an appropriate time, the supply of current is guided to the closer coil 4a (the current I for the coil 4a is shown with a solid line in the I-t diagram). Thus, this coil 4a xe2x80x9ccatchesxe2x80x9d the armature 4d (this operation is the so-called xe2x80x9ccatchxe2x80x9d process), and holds it finally in the position xe2x80x9clift valve closedxe2x80x9d, illustrated on the right hand side of FIG. 1. After the armature 4d has been securely caught by the coil 4a, the current in this coil is switched over, moreover, to a lower holding current level (see I-t diagram).
Starting from the position, illustrated on the right hand side in FIG. 1, the reverse transition from xe2x80x9clift valve closedxe2x80x9d to xe2x80x9clift valve openxe2x80x9d takes place analogously. The current I in the closer coil 4a is turned off and the current for the opener coil 4b is turned on with a time delay. Generally, for the supply of current to be guided to the coils 4a, 4b, sufficient electric voltage is applied to said coils, whereas the turning off of the electric current I is triggered by lowering the electric voltage to the value xe2x80x9czeroxe2x80x9d. The necessary electric energy for operating each actuator 4 is taken either from the electrical system of the vehicle, driven by the related internal combustion engine, or provided by means of a separate energy supply, adjusted to the valve drive mechanism of the internal combustion engine. In this respect the electric voltage is held constant by the energy supply; and the coil current I of the actuators 4, assigned to the internal combustion engine lift valves 1, is controlled in such a manner by a controller that the necessary forces for the opening, closing and holding of the lift valve(s) 1 in the desired position are generated.
In the state of the art, described above, the aforementioned controller or a control unit adjusts through timing the coil current I during the so-called catch process (wherein one of the two coils 4a, 4b endeavors to catch the armature 4d) to a value that is large enough to catch reliably the armature 4d under all conditions. Now the force of the catching electromagnetic coil 4a or 4b on the armature 4d is approximately proportional to the current I and inversely proportional to the distance between the coil and the armature. If at this stagexe2x80x94as in the known state of the art xe2x80x94a constant current I is set, the magnetic force, acting on the armature 4d, increases, as it approaches the respective coil 4a or 4b, catching it, inversely proportional to the remaining gap, thus increasing the acceleration and speed of the armature. The result is a high landing speed of the armature 4b on the respective electromagnetic coil 4a or 4b, the consequence of which is, first of all, high wear in the actuator 4 and, secondly, also high significant noise development. Another drawback lies in the change over losses of the transistors, which losses are generated during the briefly described timed current regulation and which result in increased power absorption and temperature load on the controller that is used and increased electromagnetic radiation into the leads of the actuators.
The state of the art, disclosed in German Patent document DE 195 30 121 A1 discussed above, does offer an improvement especially with respect to the noise development and the actuator wear. It proposes a process for reducing the landing speed of the armature on an electromagnetic actuator. As the armature approaches the pole surface of the coil catching the armature, the voltage, applied to this coil, is limited (that is, essentially reduced) to a specified maximum value so that the current, flowing through the coil, drops during a part of the time that the voltage is limited. Furthermore, it is also stated that the degree to which the voltage is limited or reduced can be specified in a family of characteristics. The corresponding values and, in particular, also the respective time at which this voltage reduction is supposed to start, can be determined experimentally.
The German Patent document DE 198 32 198 A1 describes a process for reducing the landing speed of an armature on the electromagnetic actuator, where in the braking phase, which follows a catch phase, a timed electric voltage is applied. In so doing, the respective switching times and the voltage-to-timing ratio of a regulator are determined with the aid of a desired trajectory, describing the desired movement of the armature.
The actual voltage curves for the implementation of this process are usually found with so-called controller based design methods. They involve empirical or numerical, thus arithmetic methods, with which a voltage curve is determined when specific boundary conditions are set and with which the desired result can be shown.
However, these past methods did not take into consideration that from time to time there are high current eddies in the armature. These eddies result in energy losses and inaccuracies in the individual valve timing. In the past these drawbacks were remedied in that the current eddies were largely avoided through the use of a laminated armature or an armature with low electric conductivity. However, such solutions usually lead to higher costs.
The object of the present invention is therefore to provide a process in which the high current eddies in the armature can be largely avoided during the operation of an electromagnetic actuator.
This problem is solved according to the invention by a process for operating an electromagnetic actuator, in particular to actuate a gas exchange lift valve of an internal combustion engine, with an armature, which is moved oscillatingly between two electromagnetic coils against the force of at least one return spring via an alternating supply of current to the electromagnetic coils and whereby, as the armature approaches the coil subjected first to a current flow, during the so-called catch process the voltage, applied to the coil catching the armature, is reduced, characterized in that a voltage control method is chosen with a voltage curve, with which an eddy current, calculated with a mathematical model, is minimized in the armature.
An important idea of the present invention is the consideration of the eddy currents, induced in the armature, during preparation of the voltage curve to regulate/control the electromagnetic actuator. From a number of possible voltage curves, which allow the operation of an electric actuator in the required manner, a voltage curve can be selected in the sense of avoiding eddy currents.
To understand the invention it is helpful to design an equivalent circuit diagram for the magnetic fluxes that shows the magnetic sources and the magnetic resistances. In this equivalent circuit diagram the eddy current, induced in the armature, represents a magnetic flux source that generates a magnetic flux, which flows in the opposite direction to the other magnetic flux. In considering this magnetic flux source in a mathematical model, with which the current eddies in the armature can be calculated, a voltage control method can be chosen that results in a minimum eddy current.
Preferably, a mathematical or numerical model is used to find the voltage curve. One possibility for determining the voltage curve lies in the use of a so-called controller design method with variable structure, as is well known.
The voltage curve can then be realized by different ways and means, for example through pulse width modulation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Process for operating an electromagnetic actuator

Bayerische Motoren Werke Aktiengesellschaft


A method of making tree seedling plugs which permits the plug to be transplanted earlier is provided. The tree seeds are planted in a structured soil growing medium, and a miniplug is formed which may is then transferred to a standard size growing cell for further development to form the plug.

Reforestation of coniferous forests after logging or forest fires is generally accomplished by tree planting by hand. Tree planters, on foot and carrying a supply of tree seedlings, form holes in the soil using a tool called a mattock and insert a tree seedling into the hole, and the soil is pressed around the roots of the seedling by the planter. Due to the nature of coniferous forests, such re-planting is often carried out on rugged terrain, in difficult soil conditions. Also, such forests are typically in a northern climate with a short growing season. There is therefore a short window during which the re-planting of seedlings has the maximum chance for success, when the soil is sufficiently warm and moist with a long enough season remaining for the roots of the seedling to develop enough for survival.
Previously, tree seedlings were grown for up to three years in a nursery and then transplanted with bare roots. The disadvantages of such "bare root" planting of tree seedlings have been outlined in the present inventor's prior U.S. Pat. No. 3,722,139. Bare root replanting of tree seedlings has a high failure rate, since the soil into which the seedling is planted may have been overly harsh, cold or dry and the seedling roots may not have time to develop adequately in a short growing season. Consequently a method of growing seedlings in a soil plug called "styroblock plugs" has been developed. The soil plug can be planted using a dibble rather than a mattock. According to the current method, styrofoam trays or blocks having an array of cylindrical cavities are used. The cavities are filled with a loose growing soil mixture consisting of peat moss, sawdust and additives covered with loose sand. Generally two tree seeds are placed in each cavity. The trays are then placed in a greenhouse for the seed to germinate in warmth and light. After about 7 months the roots of the seedling have sufficiently developed to hold the growing medium together, forming a plug. At that point the seedlings are ejected from the styrofoam blocks and wrapped and packed for shipping or storage. In this way the roots of the seedling when planted are assured of a moist growing medium.
There remain difficulties with this present method, however. Roots of seedlings which have sufficiently developed in the cavity to retain the growing medium are not ideally configured for replanting as they form a ball which is unstable when replanted, and the growing seedling may be blown over in the wind. This is particularly a problem with certain species such as lodgepole pine. It is preferable to have the seedling roots develop naturally by penetrating into the upper layers of humus. Further, a long growing time is required to allow the seedling roots to develop according to this method, typically a minimum 7 months. Generally the seedlings will be planted in Jan. and shipped in Jul. However Jun. is often a preferable month for planting in order to minimize failures. Consequently there is a need for a method of forming a seedling plug which permits transplanting at an earlier stage of development of the seedling root system.

Tree seedling plug and method of making same


A drill bit includes multiple cutting devices and a microelectronics unit. Each cutting device of the multiple cutting devices includes a cutting layer formed to cut a rock formation and a capacitive sensor disposed adjacent the cutting layer. The capacitive sensor is configured to generate an electric field across the cutting layer and to transmit a signal corresponding to a voltage associated with the electric field. The microelectronics unit of the drill bit is configured to receive the signal from the capacitive sensor of each cutting device of the multiple cutting devices such that the microelectronics unit receives multiple signals and to determine an indicator of mechanical wear of the drill bit based on a change in the voltage associated with the electric field across the cutting layer of each cutting device of the multiple cutting devices using the multiple signals.

Drill strings deployed in hard rock formations can experience severe shock and vibration during drilling operations. Such shock and vibration can lead to premature equipment failure (for example, including damage to a drill bit carried by a drill string) and to a reduction in a rate of penetration (ROP) at which the drill bit can break rock underneath the drill bit and thus deepen a wellbore. A condition of a drill bit affects both invisible lost time (ILT) and non-productive time (NPT), which make up a significant portion of the overall cost of a drilling operation. For example, ROP decreases as wear of a drill bit progresses, and NPT is associated with stopping a drilling operation to replace or repair a drill bit (for example, as part of a bit trip). Various approaches may be utilized to address the impact of shock and vibration on a drill string during a drilling operation, such as changing a rotational speed of a drill bit or a downward force applied to the drill bit (for example, a weight-on-bit, WOB), employing shock subs, and deploying memory mode vibration logging tools along the drill string. However, these approaches are often associated with one or more significant drawbacks, such as a decreased drilling efficiency, an increased risk of encountering lateral vibrations that are strong enough to damage one or more components of the drill string, and operational temperatures that exceed a desired operating temperature.


A user interface of an entity-centric knowledge discovery system presents an entity profile including a mix of structured and unstructured data relating to an entity. As a user refines the entity profile based on information gathered from various sources, the changing entity profile can be used as a substantially continuously updating query to search, retrieve, and rank new and pertinent information specifically relevant to the profiled entity. The platform described herein provide an active loop for refining an entity description and searching for additional information in which human input and machine-based algorithms can cooperate to more quickly build a comprehensive description of an entity of interest.

Many information retrieval tasks are entity-centric, and focus on particular types of entities with well-known and strongly typed attributes. For example an entity such as a company may have a number of employees, a stock symbol, a business address, a quarterly earnings date, and numerous other known attributes involving dates, dollar amounts, geographic locations, and so forth. Similarly, a person may be characterized by a birthday, a home address, a social graph, and so forth. Searching for new information about an entity from among unstructured or semistructured data requires attention to both the description of the entity and the content of documents that are retrieved in response to this description. While tools such as foldering trees have been developed to help gather and sort this type of information, there remains a need for improved tools for a user to discover and gather data into a profile for an entity.


A printing system includes a media transport system configured to transport a web of print media through a printing zone at a transport speed in a transport direction proceeding from up-web to down-web. A plurality of printheads each at least spanning the print zone and each configured to eject a radiation-curable ink. At least one PIN is unit positioned between two of the printheads relative the transport direction and configured to emit radiation onto the print media to partially cure the ink emitted by a printhead that is up-web from the PIN unit. A controller controls a power level of the PIN unit so that the radiative power level of the PIN unit decreases as the transport speed increases.

A rapid change is occurring in the commercial and industrial printing marketplace with an expanded use of digital printing presses to replace their analog counterparts. Digital printing presses have an advantage of lower "set-up" costs in that a change to a print pattern is accomplished with a file change. This improves the economics of "short run" printing and reducing a need to print large inventories of a given design.
One common form of digital printing press is a web press based upon inkjet printing of radiation curable inks. In this embodiment a roll of media is unwound and then passed through a paper path defined by a series of rollers. A part of the paper path is a print zone within which inkjet printheads eject a dot matrix pattern of fluid drops on a surface of the media thereby forming images and/or text on the media surface.
An important factor with radiation curable inks is a tendency to flow between depositing the inks and providing a radiation cure of the inks. Another factor is a tendency of inks having different primary colors to intermix. A certain amount of flow and intermixing can be desirable but there is an optimal level in order to maximize resultant image quality.
To control flow and intermixing PIN units can be used to "pin down" the ink to a certain extent to reduce flow and mixing. The effect of these units has been found to change with the transport speed of the print unit in unexpected ways.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.


Arrangements for engine compressor units are disclosed in which power cylinders operating on the two-stroke cycle are provided with charging air from a blower or other source which also provides charging air to two-cycle compressor cylinders via a separate turbocharging unit driven by the charging air and delivering more highly pressurized air to the compressor cylinders so as to increase compressor volumetric efficiency through the delivery of the precompressed inlet charges.

It is known in the art to provide a two-stroke cycle air compressor having or more cylinders driven by an internal combustion engine also having one or more cylinders. The compressor and engine cylinders may be formed within a common frame, or crankcase, and have pistons connected to a common crankshaft and the engine cylinders may be operated on either a two or four-stroke cycle.
As shown in U.S. Pat. No. 4,480,968, the subject matter of which is incorporated herein by reference as a further teaching of the present invention, the engine and compressor are preferably housed in a common crankcase and utilize a common blower both to charge and scavenge the engine cylinders and to charge the compressor cylinders, thereby increasing their volumetric charging efficiency.
Engine compressor units may be made for example by modifying engines from a line of known two-cycle diesel engines having uniflow scavenging. The modified engines are provided with nonported cylinder liners and special cylinder heads in some of the cylinders preferably those of one bank of V-type engines, to operate on a two-stroke compressor cycle. Connection of the compressor cylinder head inlet ports with the engine air box allows using pressurized charging air from the engine blower for charging the compressor cylinders also. A turbocharger driven by exhaust from the engine cylinders may be mounted to provide compressed intake air to the charging blower.


An RF component can have a reduced electromagnetic internal coupling and may be suitable for miniaturization as a result. The component includes a micro acoustic filter of ladder-type design in a housing and a double coil having a first coil segment and a second coil segment. The two coil segments are oriented in opposite directions. The two coil segments are arranged without crossover in one layer and the double coil is arranged in proximity to a parallel branch resonator of the ladder-type filter structure.

The continuous trend toward the miniaturization of RF components imposes particular requirements with regard to the mutual couplings of circuit parts in the component. The distances between the circuit parts decrease as a result of a miniaturized design. As a result, undesired signal components from one part can be more easily coupled into another part. If duplexers, for example, were miniaturized without further measures, then the isolation would be impaired. Starting from a critical value for the isolation, the miniaturization would no longer be possible since the duplexer would then no longer be able to fulfill predefined requirements with regard to the isolation.
U.S. Patent Application Publication No. 2011/0254639A1 discloses arranging a capacitive element between antenna connection or receiving connection of a duplexer or between transmitting connection and receiving connection in order to reduce crosstalk.
International Patent Publication No. WO 2011/092879A1 discloses a coil at a transmitting connection. In this case, the coil is arranged on the substrate in such a way that it becomes located alongside its filter-topologically adjacent resonators.
U.S. Pat. No. 7,151,430B2 discloses a coil structure for reducing an inductive coupling. In this case, the coil has regions in which parts of the coil turn overlap other parts.
International Patent Publication No. WO 2011/101314 discloses micro acoustic filters having a Figure eight current loop.
The documents cited above specify measures for reducing electromagnetic coupling, but are technically relatively complex to realize.

RF component with reduced coupling and suitable for miniaturization


A battery control system connected to a battery equipped with an explosion-proofing mechanism for cutting off an electric current when the battery enters an overcharge state, including: a cell voltage detection unit that detects voltage at the battery; a storage unit that stores information pertaining to the battery conditions; an overcharge decision-making unit that makes a decision as to whether or not the battery is in an overcharge state; a storage control unit that engages the storage unit to store information pertaining to the overcharge state when the overcharge decision-making unit decides that the battery is in an overcharge state; and an explosion-proofing decision-making unit that decides that the explosion-proofing mechanism in the battery has actuated if the overcharge information is stored in the storage unit and the cell voltage detected by the cell voltage detection unit is lower than a predetermined lower limit value.

There are explosion-proofing mechanisms known in the related art that cut off an electric current flowing to a sealed secondary battery when it becomes overcharged resulting in an increase in the internal pressure, so as to prevent a further rise in the internal pressure. PTL1, for instance, discloses an explosion-proofing mechanism having a diaphragm that inverts when there is a rise in the internal pressure so as to break the connection inside the battery and thus cut off the electric current.

Battery control system and vehicle control system