A first pair of antennas are mounted on a satellite spaced along a first axis and a second pair of antennas are spaced along a second axis for receiving signals from another satellite in orbit with the satellite, the first and second axes being orthogonal to a yaw axis that points toward the centroid of the celestial body about which the satellite orbits. Each pair of antennas are used to derive phase angle and signal strength differences, and these differences are used for deducing a yaw orientation of the satellite about the yaw axis.

The present invention relates to sensor systems and methods for determining the orientation of a satellite in orbit about earth or other celestial body. The invention relates more particularly to sensor systems and methods for determining the yaw orientation of a yaw-steered satellite about an axis pointing toward the center of the earth or other celestial body.
Optical sensors for satellites have been developed for viewing earth in order to derive position information of the satellite relative to earth. In such schemes, it is known to direct light from a field of view of the sensor onto a focal plane array, such as a charge coupled device (CCD), comprising a grid of pixels. The field of view and the optics of the sensor are typically designed such that at least part, and more typically all, of the circumference of the earth""s limb (i.e., the transition region between the earth and space) can be imaged onto the focal plane when the sensor is pointed in a suitable direction relative to the earth. The relative location of the image of the earth limb on the focal plane is determined by finding the pixels at which a large gradient in intensity of the incident light energy is located, a large gradient indicating a transition between earth and space. Using an appropriate algorithm, it is possible to determine the rotational orientation of the sensor, and hence of the satellite, about two orthogonal axes based on the locations of the transition pixels of the focal plane array. See, for example, U.S. Pat. No. 6,026,337.
A number of patents for various types of optical sensors have been acquired by the assignee of the present application, including U.S. Pat. Nos. 5,502,309, 5,534,697, 5,627,675, and 5,841,589, the entire disclosures of which are hereby incorporated herein by reference. The sensors described in all of the aforementioned patents have a single field of view for looking at the limb of the earth. As a rule, a sensor seeing the circular limb of the earth can be used for deriving position information about two axes, but cannot be relied upon for providing position information about the third axis. For example, if the sensor is looking along an axis that passes through the centroid of the earth, then any rotation of the sensor about that axis will not change the image of the earth limb on the focal plane array. This situation is not unlikely in many cases. For instance, some types of satellites are intentionally rotated about a yaw axis that is directed along the nadir vector through the centroid of the earth. As an example, yaw-steered satellites such as GPS satellites are deliberately yawed in order to position the solar panels of the satellite in an optimum position for receiving the sun""s radiation. If the optical sensor is mounted on the satellite so as to be looking along the yaw axis, then it is not possible for the sensor to provide information about the rotational position of the satellite about the yaw axis.
For this reason, on satellites using a limb-looking optical sensor as described above, it is necessary to derive the position information about the third axis by other means. One way to do this is to detect another celestial body with the sensor, such as stars or the sun. This solution, however is not entirely satisfactory. A star sensor requires an elaborate star map, and is generally not very accurate. A sun sensor only works when the sun is within view, such that another method for determining yaw orientation is required whenever the sun disappears behind the earth, or when the sun is in a location displaced a substantial amount from an orthogonal to the yaw axis.
U.S. Pat. No. 6,018,315 discloses a method and system for determining yaw orientation of a satellite using signals received from a global positioning system (GPS) satellite. A pair of spaced antennas are mounted on the satellite whose yaw orientation is to be deduced, and signals from the GPS satellite are received by both antennas and sum and difference signals are generated based on phase differences between the signals received by the antennas. The yaw angle of the subject satellite is correlated with the sum and difference signals such that yaw angle can be deduced from these signals.
One problem with using a method employing two antennas such as that of the ""315 patent is that the yaw angle solution can be multiple-valued. That is, the same sum and difference signals can be generated for two or more different yaw angles. For instance, if the pair of antennas is rotated about the yaw axis by 180 degrees, then each antenna will occupy the position previously occupied by the other antenna, and hence the same sum and difference signals will be generated by the antenna pair. This is not generally a problem if continuous tracking of the yaw orientation is performed, because the orientation of the satellite will be clear based on the previous yaw orientation history and the current sum and difference signals. However, if a computer upset should occur such that the yaw orientation must be established without benefit of knowledge of the previous yaw orientation history, then the multiple-valued nature of the yaw solution based on the sum and difference signals may make it impossible to deduce with certainty the yaw orientation of the satellite based solely on the sum and difference signals.
The present invention addresses the above needs by providing a method and apparatus for determining the yaw orientation of a satellite in which two (or more) separate pieces of information are generated for any given yaw orientation, and the combination of the two pieces of information is unique for each yaw orientation, thus avoiding the multiple-value problem. This is accomplished in accordance with the invention by providing two (or more) pairs of antennas. A first pair is spaced apart on the satellite along a first axis, such as the roll axis of the satellite. A second pair is spaced apart on the satellite along a second axis, such as the pitch axis of the satellite. Of course, the first and second axes can be oriented in any arbitrary sense relative to the satellite body axes as long as the orientation of the axes is known relative to the body axes, and as long as neither pair is aligned along the yaw axis. Each antenna pair is used to generate a difference signal by comparing the signals arriving at the two antennas. Orientation of the satellite about the yaw axis is deduced based on both difference signals.
In one embodiment of the invention, the difference signal derived for one antenna pair represents a phase angle difference between the signals arriving at the two antennas. The difference signal for the other antenna pair represents a signal strength difference derived by comparing the strengths of the signals arriving at the two antennas. In a preferred embodiment, each pair of antennas is used to derive both a phase angle difference and a signal strength difference. Using both the phase and signal strength difference, it is possible to deduce the yaw orientation of the satellite even when there has been a computer upset causing the yaw orientation history to be lost.
For example, if the first pair of antennas is aligned along a direction perpendicular to the direction along which a signal is arriving from the other satellite when such a computer upset occurs, it would be impossible to determine the correct yaw orientation based solely on the zero phase and strength difference signals that would be generated by the first antenna pair. The sensor system could determine that the first antenna pair is aligned perpendicular to the arrival direction of the signal, but there are two possible yaw orientations 180 degrees apart that satisfy that condition, and it would not be possible to determine which of those orientations is the true yaw orientation based only on the first antenna pair. However, in accordance with the present invention, the second antenna pair in this scenario provides a non-zero difference signal based on the strengths of the signals arriving at each antenna, and the sense of that difference is positive in one of the two possible yaw orientations and is negative in the other possible yaw orientation. Thus, the true yaw orientation of the satellite can be determined based on the information provided by both antenna pairs.
In a preferred embodiment of the invention, the satellite orientation about all three axes is determined by combining the antenna sensor system with an optical sensor arrangement that is operable to map a view of the celestial body onto at least one focal plane array and to determine orientations of the satellite about two body axes (e.g., the pitch and roll axes) thereof based on a location of a centroid of the earth or other celestial body relative to a center of the focal plane array. The optical sensor arrangement can be one such as described in commonly assigned U.S. patent application Ser. No. 09/756,395, filed Jan. 8, 2001, and entitled xe2x80x9cMethod and Sensor for Capturing Rate and Position and Stabilization of a Satellite Using At Least One Focal Planexe2x80x9d, the disclosure of which is hereby incorporated herein by reference.
Preferably, the antennas of the sensor system have directional sensitivity patterns such that the strength of the signal produced by each antenna is a function of the direction in which the received signal arrives at the antenna. In a preferred embodiment, the antennas of each pair are oriented such that minimum sensitivity occurs when signals arrive in the direction along which the two antennas are spaced apart and maximum sensitivity occurs when the signal arrives perpendicular to this direction. Preferably, one pair is spaced apart along the roll axis of the satellite and the other pair is spaced apart along the pitch axis.
The antennas are preferably mounted such that they all lie substantially in the same plane, which is normal to the yaw axis. This arrangement ensures that the difference signals are substantially unaffected by pitch and roll movements of the satellite.
The two pairs of antennas can comprise four antennas. Alternatively, however, one pair can comprise first and second antennas, and the other pair can comprise one of the first and second antennas together with a third antenna.
The sensor system can receive signals from more than one satellite in orbits in substantially the same orbital plane as the first satellite. For example, the first satellite can be one of a constellation of GPS satellites. The first satellite can receive signals from a satellite located ahead of the first satellite and from another satellite located behind the first satellite in orbit. An independent yaw orientation determination can be made based on each satellite""s signal, thus providing redundancy and improving reliability of the yaw determination.

Sensor system and method for determining yaw orientation of a satellite


Provided herein is an apparatus, including an inner component, wherein the inner component includes a thrust plate; an outer component, wherein the inner component and the outer component are positioned for relative rotation, and wherein the inner component and the outer component are positioned to form at least one bearing having a groove pattern that imparts a predetermined direction to the rotational motion of the inner component and the outer component; and a gas inlet operable to receive a pressurized gas.

Conventional, externally pressurized, air bearing spindles are designed such that the spindle rotation is bidirectional, allowing a motor to rotate the spindle in either a clockwise direction or a counterclockwise direction. This bi-directionality allows for these conventional, externally pressurized, air bearing spindles to be used in a wide variety of applications, some of which utilize clockwise spindle rotation, some of which utilize counterclockwise spindle rotation, and some of which alternately utilize clockwise and counterclockwise spindle rotation. Some applications such as servo track writing on raw media for hard disk drives ("HDD") are affected by spindle performance.


A method of making a metal snow guard is disclosed. The snow guard has a solid layer of soldering material on its base to be heated and melted with application of heat to the upper side of the snow guard to solder the base to an underlying metal roof. The soldering material may be applied as spaced spots or projections providing a rough surface on the underside of the snow guard. The amount of solder and/or flux in the solid layer is limited so that the solder and/or flux does not flow outwardly from the snow guard and run down the metal roof thereby damaging or marring the metal roof surface. The snow guards may be formed of a few pieces of sheet metal. The projections of soldering material may be formed by forcing a paste of solder and flux through spaced holes in a plate or screen onto the base.

One particularly successful snow guard having a gem-like appearance and made of plastic and usually of colored plastic is disclosed in U.S. Pat. Nos. 5,901,507 and 5,471,700 to Smeja, et al. The present invention is not limited to this particular shape or kind of snow guard but is applicable to various other shapes and kinds of snow guards. The particular shapes and kinds of snow guards illustrated and described herein are the preferred embodiments of the invention and are merely exemplary.
The snow guards shown in the aforesaid patents have been very successful from a commercial standpoint and were made in plastic of different colors. This snow guard was not only purchased and installed because of its functional capabilities, but is also purchased and installed as a medallion in warm climates only because decorative and esthetic appeal on a building. There is a need to provide a similar shape of snow guard but in metal where the architect or building proprietor wants a particular color and material. Often, it is desired to make the snow guards of the same material as the roof, so that the snow guards blend in with the roof of the same color and same material. Although the plastic molded snow guards may be colored to have the appearance of copper for a copper metal roof, a gold appearance for a gold roof, a green appearance for a green metal roof, etc., the snow guards being made of plastic rather will still have a noticeable look of being made of a different material and often with a slight variation in color. Of course, some will want contrasting or accenting colors of snow guards for their roofs. Whatever the reason, there is a reason for making snow guards from flat metal sheets such as copper, stainless steel, terne metal, galbanum, zinc coated steel, lead coated copper, etc. In other instances, the metal sheets may have a color coating on the surface of metal sheet which is colored to meet an owner's desire for a slate roof, a shingle roof or a metal roof.
When making folded metal snow guards, the aesthetics are important for such a highly visible product. While the product could be folded from a single sheet or several metal sheets and joined together, it is preferred that the product appear substantially seamless or with a minimum of visible seams in the installed position. Further, because some of the metal sheets are expensive, it is preferred that the construction be made without excessive scrap waste. Usually, the sheet metal will be stamped with holes therein and with irregular shapes on the side edges for panel edges that are to be erected. This lends to the formation of scrap. Also, where the sheet is coated as with a color, it is less expensive to make a sheet colored on one side rather than two sides and to fold the sheet to form the snow guard with only the one-coated side being visible.
Typically, snow guards are fastened to roofs with fasteners such as screws or nails, with adhesives, or with solder when securing a metal snow guard to a metal roof. The typical solder operation of a worker applying solder and flux and heating them to liquify the solder and to form the solder connection is time consuming and expensive. That is, the installer will have a roll of solder wire and a flux material and he will lay the flux and the solder against an upper edge or underneath the upper edge of the snow guard inclined on the roof to heat the roof, the snow guard edge, the flux and the solder with a propane torch to melt or liquify the solder and bring the metal of the snow guard and roof to the temperature necessary for soldering together. Although the upper side edges of the snow guard may be soldered, the lower edges and the bottom edge of the snow guard may not be soldered or soldered only with extreme care to avoid running of solder along the roof surface below the snow guard. Good soldering technique is a difficult task to learn in that one really needs three hands with one hand to hold the snow guard in place on an inclined roof, a second hand to hold the solder, and a third hand to apply the flux. If too little solder is applied, a good connection to the roof is not attained. If too much solder or flux is applied, it will run down the expensive metal roof and mar its appearance. There is no good or easy way to remove any solder streaks from the metal roof without affecting its appearance.
Also, it is necessary to apply high temperature heat, e.g., 500°–600° F. from a torch to the snow guard to melt the underlying solder at about 370°–390° F. The snow guard will become so hot that the person doing the soldering cannot hold the snow guard in position while it is being soldered. If insufficient heat is applied and a weak, cold solder joint will be made between the snow guard and the roof. Thus, today commercial installers of snow guards attach them to the roof with fasteners or adhesives because of the difficulties in applying the right amount of solder, heat and a good soldering technique.
Thus, there is a need for a new method of attaching metal snow guards to metal roofs. Also, there is a need for new and improved snow guards.


For reducing Doppler artifacts in the wave-field synthesis due to delay changes from one time to a second time, first, the delay for the first time and the delay for the second time are determined. Then, a value of an audio signal delayed by the first delay for the current time and the value for the audio signal delayed by the second delay for the current time are determined. Then, the first value is weighted by a first weighting factor and a second value is averaged with a second weighting factor, whereupon the two weighted values are added up to obtain a discrete value for the current time of the component in a loudspeaker signal for a loudspeaker based on a virtual source. Thus, by knowing a delay present at a later time, panning is obtained from a delay to a subsequent delay, which reduces undesired Doppler artifacts.

1. Field of the Invention
The present invention relates to wave-field synthesis systems and particularly to wave-field synthesis systems allowing moving virtual sources.
2. Description of the Related Art
There is an increasing demand for new technologies and innovative products in the field of consumer electronics. Here, it is an important prerequisite for the success of new multimedia systems to offer optimum functionalities or capabilities, respectively. This is achieved by the usage of digital technologies and particularly computer technology. Examples therefore are applications offering an improved realistic audiovisual impression. In prior art audio systems, a significant weak point is the quality of the spatial sound reproduction of real but also virtual environments.
Methods for multichannel loudspeaker reproduction of audio signals have been known and standardized for many years. All common techniques have the disadvantage that both the location of the loudspeakers and the position of the listener are already imprinted in the transmission format. If the loudspeakers are positioned in a wrong way with regard to the listener, the audio quality suffers significantly. An optimum sound is only possible in a very small area of the reproduction room, the so called sweet spot.
An improved natural spatial impression as well as stronger enclosure during audio reproduction can be obtained with the help of new technology. The basics of this technology, the so called wave-field synthesis (WFS) have been researched at the TU Delft and have been presented for the first time in the late 80ies (Berkhout, A. J.; de Vries, D.; Vogel, P.: Acoustic control by Wave-field Synthesis. JASA 93, 1993).
Due to the huge requirements of this method with regard to computing effort and transmission rates, the wave-field synthesis has so far only rarely been applied in practice. Only the progresses in the field of microprocessor technique and audio encoding allow the usage of this technology in specific applications today. First products in the professional field are expected next year. In a few years, the first wave-field synthesis applications for the consumer field will come on the market.
The basic idea of WFS is based on the application of the Huygens principle of the wave theory.
Every point captured by a wave is the starting point of an elementary wave, which propagates in a spherical or circular way.
Applied to acoustics, any form of an incoming wave front can be reproduced by a large number of loudspeakers arranged next to another (a so called loudspeaker array). In the simplest case, a single point source to be reproduced and a linear arrangement of the loudspeakers, the audio signals of every loudspeaker have to be fed with a time delay and amplitude scaling such that the emitted sound fields of the individual loudspeakers overlay properly. With several sound sources, the contribution to every loudspeaker is calculated separately for every source and the resulting signals are added. In a virtual space with reflecting walls, the reflections can also be reproduced via the loudspeaker array as additional sources. Thus, the calculation effort depends heavily on the number of sound sources, the reflection characteristics of the recording room and the number of loudspeakers.
The particular advantage of this technique is that a natural spatial sound impression is possible across a large area of the reproduction room. In contrary to the known techniques, direction and distance from the sound sources are reproduced very accurately. To a limited degree, virtual sound sources can even be positioned between the real loudspeaker array and the listener.
Although wave-field synthesis functions well for surroundings whose conditions are known, irregularities occur when the conditions change or when wave-field synthesis is performed based on surrounding conditions which do not correspond to the actual condition of the surroundings, respectively.
The technique of wave-field synthesis can also be used advantageously to add a corresponding spatial audio perception to a visual perception. So far, during production in virtual studios, the focus was on the production of an authentic visual impression of the virtual scene. The acoustic impression matching the image is normally imprinted on the audio signal afterwards by manual operating steps in the so-called postproduction or is considered to be too expensive and too time-consuming to realize and is thus neglected. This causes normally a discrepancy between individual sense impressions, which causes the designed space, i.e. the designed scene, to be considered as less authentic.
In the expert publication "Subjective experiments on the effects of combining spatialized audio and 2D video projection in audio-visual systems", W. de Bruijn and M. Boone, AES convention paper 5582, May 10th to 13th, 2003, Munich, subjective experiments with regard to the effects of combining spatial audio and a two-dimensional video projection in audiovisual systems are presented. Particularly, it is emphasized that two speakers standing at different distances to a camera, who stand almost behind one another, can be understood better by an audience when the two persons standing behind one another can be seen and reconstructed as different virtual sound sources with the help of wave-field synthesis. In that case, it has been found out by subjective tests that a listener can better understand and differentiate the two speakers speaking simultaneously when they are separated.
In a conference contribution for the 46th international academic colloquium in Ilmenau from Sep. 24 to 27, 2001, with the title "Automatisierte Anpassung der Akustik an virtuelle Räume", U. Reiter, F. Melchior and C. Seidel, an approach for automating sound post-processing processes is presented. Therefore, the parameters of a film set required for the visualization, such as room size, texture of the surfaces or camera position and position of the actors are checked for their acoustic relevance, whereupon corresponding control data are generated. These influence then in an automated way the effect and post-processing processes used for postproduction, such as the adaptation of the speaker volume dependency on the distance to the camera or the reverberation time in dependence on room size and wall conditions. Here, it is the aim to enforce the visual impression of a virtual scene for an increased perception of reality.
It is intended to enable "listening with the ears of the camera" for making a scene appear more real. In this connection, it is intended that a correlation between sound event location in the image and listening event location in the surround field is as high as possible. This means that sound source positions are constantly adapted to an image. Camera parameters, such as zoom, are also to be incorporated in the sound design like a position of two loudspeakers L and R. Therefore, tracking data of a virtual studio are written into a file by the system together with an associated time code. Image, sound and time code are recorded simultaneously on an VTR. The Camdump file is transmitted to a computer, which generates control data for an audio workstation therefrom and outputs them via an MIDI interface synchronously to the image coming from the VTR. The actual audio processing as well as positioning the sound source in the surround field and inserting earlier reflections and reverberation is performed within the audio workstation. The signal is rendered for a 5.1 surround loudspeaker system.
Camera tracking parameters as well as positions of sound sources in the recording setting can be recorded in real film sets. Such data can also be generated in virtual studios.
In a virtual studio, an actor or presenter is alone in a recording room. Particularly, he stands in front of a blue wall, which is also referred to as blue box or blue panel. On this blue wall, a pattern of blue and light-blue stripes is disposed. Special about this design is that the stripes have a different width and thus a plurality of stripe combinations result. During post-processing, when the blue wall is replaced by a virtual background, it is possible to determine exactly which direction the camera looks due to the unique stripe combination on the blue wall. With the help of this information, the computer can determine the background for the current angle of view of the camera. Further, sensors at the camera are evaluated, which detect additional camera parameters and output the same. Typical parameters of a camera, which are detected via sensor technology, are the three translation degrees x, y, z, the three rotation degrees, which are also referred to as roll, tilt, pan, and the focal length or the zoom, respectively, which is equal to the information about the aperture angle of the camera.
In order to be able to determine the exact position of the camera even without image recognition and without expensive sensor technique, the tracking system can also be used, which consists of several infrared cameras, which determine the position of an infrared sensor mounted to the camera. Thereby, the position of the camera is also determined. With the camera parameters provided by the sensor technology and the stripe information evaluated by image recognition, a real time computer can now calculate the background for the current image. Then, the blue hue, which the blue background had, is removed from the image, so that instead of the blue background the virtual background is brought in.
In most cases, a concept is followed, which is based on getting an acoustic overall impression of the visually imaged scene. This can be described with the expression "full shot" coming from image design. This "full shot" sound impression remains mostly constant via all settings in a scene, although the optical angle of view on things often changes very much. Optical details are emphasized by corresponding angles or moved into the background. Countershots in creating dialogs in films are also not reproduced by sounds.
Thus, there is the need to embed the audience acoustically into an audiovisual scene. In this connection, the screen or the image area is the line of vision and the angle of view of the audience. This means that the sound is to follow the image in the form that it always corresponds to the image. This is particularly important for virtual studios since there is typically no correlation between the sound of the moderation, for example and the surroundings where the presenter is at the moment. In order to get an audiovisual overall impression of the scene, a room impression matching the rendered image has to be simulated. In that context, the location of a sound source, as it is perceived by, for example, an audience of a cinema screen, is a significant subjective characteristic in such a sound concept.
In the audio domain, a good spatial sound can be obtained for a large listener area by the technique of wave-field synthesis (WFS). As it has been discussed, the wave-field synthesis is based on the principle of Huygens, according to which wave fronts can be formed and structured by overlaying elementary waves. According to mathematically correct theoretical description, an infinite amount of sources in infinitely small distance would have to be used for generating the elementary waves. Practically, however, a finite amount of loudspeakers are used in a finite small distance to each other. According to the WFS principle, each of these loudspeakers is controlled by an audio signal from a virtual source, which has a certain delay and a certain level. Levels and delays are normally different for all loudspeakers.
In the audio domain exists a so called natural Doppler effect. This Doppler effect occurs from a source sending an audio signal with a certain frequency, a receiver receiving the signal and a movement of the source taking place relative to the receiver. Due to an "extension" or "compression" of the acoustic waveforms, this causes the frequency of the audio signal to change for the receiver according to the movement. Normally, a person is the receiver and hears this frequency change directly, for example when an ambulance with siren moves towards a person and then passes the person. The person will hear the siren at the time when the ambulance is in front of him with a different pitch than when the ambulance is behind him.
A Doppler effect exists also in the wave-field synthesis or sound field synthesis, respectively. It is physically based on the same background as the above-described natural Doppler effect. However, in contrary to the natural Doppler effect, there is no direct path between sender and receiver in sound field synthesis. Instead, a differentiation is made in that there is a primary transmitter and a primary receiver. Above that, a secondary transmitter and a secondary receiver exist. This scenario will be discussed below with reference to FIG. 7.
FIG. 7 shows a virtual source 700, which moves from a first position, which is indicated by an encircled "1" in FIG. 7 over time along a path of movement 702 to a second position, which is indicated in FIG. 7 by an encircled "2". Further, three loudspeakers 704 are shown schematically, which are to symbolize a wave-field synthesis loudspeaker array. Further, there is a listener 706 in the scenario, which is arranged in the example shown in FIG. 7 such that the path of movement of the virtual source is a circular path, which extends around the listener, who is the center of this circular path. The loudspeakers 704, however, are not disposed in the center, in that at the time when the virtual source 700 is at the first position, the same has a first distance r1 from a loudspeaker and that the source then has a second distance r2 to the source in its second position. In the scenario shown in FIG. 7, r1 is unequal r2, while R1, which means the distance of the virtual source from the listener 706 is equal to the distance of the listener 706 from the virtual source at a time 2. This means that no distance change of the virtual source 700 takes place for the listener 706. On the other hand, there is a distance change of the virtual source 700 relative to the loudspeakers 704, since r1 is unequal to r2. The virtual source represents the primary transmitter, while the loudspeakers 704 represent the primary receiver. Simultaneously, the loudspeakers 704 represent the secondary transmitter, while the listener 706 represented the secondary receiver.
In wave-field synthesis, the transmission between primary transmitter and primary receiver takes place "virtually". This means that the wave-field synthesis algorithms are responsible for extension and compression of the wave front of the waveforms. At the time when a loudspeaker 704 receives a signal from the wave-field synthesis module, there is no audible signal at first. The signal only becomes audible after being output by the loudspeaker. Thereby, Doppler effects can occur at different locations.
If the virtual source moves relative to the loudspeakers, every loudspeaker reproduces a signal with different Doppler effect, depending on its specific position with regard to the moving virtual source, since the loudspeakers are in different positions and thus the relative movements are different for every loudspeaker.
On the other hand, the listener can also move relative to the loudspeakers. However, particularly in a cinema setting, this is an insignificant case in practice, since the movement of the listener with regard to the loudspeakers will always be a relatively slow movement with a relatively small Doppler effect, since the Doppler shift, as it is known in the art, is proportional to the relative motion between transmitter and receiver.
The former Doppler effect, which means when the virtual source moves relative to the loudspeakers, can sound relatively natural but also very unnatural. This depends on the direction of the movement. If the source moves away from the center of the system or towards the same in a straight manner, a rather natural effect results. With reference to FIG. 7, this would mean that the virtual source 700 moves, for example, along the arrow R1 away from the listener.
However, if the virtual source 700 "encircles" the listener, as it is illustrated with regard to FIG. 7, a very unnatural effect results, since the relative motion between primary source and primary receiver (loudspeaker) are very strong and also very different within the different primary receivers, which is in sharp contrast to nature, wherein the case of encircling the source to listener no Doppler effects results, since no distance change occurs between source and listener.

Calculating a doppler compensation value for a loudspeaker signal in a wavefield synthesis system

Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.


Disclosed are trichloroisocyanuric acid compositions that have improved algicidal and/or fungicidal properties yet are relatively safe and non-corrosive. The compositions preferably contain between about 50% and about 95% TCCA, between about 0.5% and about 7% glycoluril, between about 2% and about 40% alum, and between about 2% and about 40% borax. The compositions generate substantially less chlorine gas than would be expected from the teachings of the prior art, especially when wet. The inventive compositions are therefore less toxic and less corrosive.

Chloroisocyanuric acids such as trichloroisocyanuric acid ("TCCA") have long been used as sanitizers for water systems such as swimming pools, spas, etc. One drawback to this use however, is that chloroisocyanuric acids generate chlorine or chlorine-containing gases that are hazardous to human health and corrosive to water treatment equipment. Corrosive chlorine gas also adversely affects the packaging used to store the chloroisocyanuric acid, so that storage problems associated with the decomposition of the sanitizer are compounded by storage problems associated with the corrosion of the packaging itself.
The evolution of chlorine gas from TCCA-containing compositions is especially pronounced when the TCCA is wet, such as when the TCCA is formulated into solid pucks or tablets that are placed into water to sanitize the system. For example, in swimming pools it is common to use chemical feeder systems that rely on pumps to recirculate the treated water throughout the system. In many cases, the pump is turned off at night, and when the attendant opens the feeder in the morning the initial shock from built-up chlorine gas may be strong enough to make the attendant sick or disoriented. These problems are well known to the swimming pool chemical industry, and sanitizers that have a reduced level of chlorine gas evolution have long been sought.
It is also known that boron derivatives such as sodium tetraborate (borax) provide beneficial algicidal and fungicidal properties to water. Unfortunately however, boron derivatives are known to promote the undesirable chlorine gas evolution from TCCA as described above. For example, U.S. Pat. No. 5,021,186 to Ota et al. shows that compositions comprising sodium tetraborate (9 g) and TCCA (21 g) generate 6.3 mg chlorine gas, compared to the 0.31 mg gas generated by a like amount of TCCA alone.
Finally, it is known that in some situations aluminum sulfates improve the stability of chloroisocyanuric acids and correspondingly reduce the evolution of chlorine-containing gas from such compositions. The benefits of adding alum to TCCA are limited however, and are not believed to be enhanced by adding gas-generating compounds such as boron derivatives to the alum/TCCA compositions. In fact, the contrary expectation has prevailed in the art, with skilled artisans believing that adding boron derivatives to the alum/TCCA compositions would result in unsatisfactory levels of chlorine gas generation.
In spite of the known disadvantages of using chloroisocyanuric acid and borax in water treatment systems, a need continues for trichloroisocyanuric acid compositions that take advantage of the beneficial algicidal and/or fungicidal properties of borax yet are relatively safe and non-corrosive. The present invention addresses that need.

Chloroisocyanuric acid composition having reduced gas evolution


A frame bar processing punch press having a bottom die holder holding a bottom die, and an upper die holder holding an upper die, the upper die holder being driven by a reciprocating rod to strike the upper die against the workpiece carried on the bottom die, the bottom die holder having a horizontal top plate which holds the bottom die, a horizontal bottom plate, and a flat vertical board on the middle between the horizontal top plate and the horizontal bottom plate, the flat vertical board having at least one vertical sharp edge at one side for guiding the workpiece into processing position.

The present invention relates to a punch press, and more particularly to a window frame bar processing punch press specifically designed for processing window or door frame bars.
A frame bar for a window or door may have to be processed at the job site to provide an opening and mounting tabs in the opening for mounting a strike plate for a lock. However, it is complicated to make an opening on a window or door frame bar and mounting tabs in the opening manually at the job site. Furthermore, the quality of the mounting tabs is poor because it is manually processed.

Window/door frame bar processing punch press


To provide a wash tank which is excellent in washing effect with a simple structure, compact, highly practical and effective in washing small molded parts made of rubber or plastic, the wash tank includes a sealable lid having a washing fluid outlet, a conical bottom wall portion having a washing fluid inlet and a cylindrical side wall portion, having a draft tube in a bugle-like shape a bottom end and an upper end of which are expanded and which is disposed at the inside of the tank and a partition plate arranged at a front face of the draft tube and further provided with a jet stream nozzle at a washing fluid inlet portion where the tank is constituted reversibly.

1. Field of the Invention
The present invention relates to a wash tank for efficiently washes, sterilizes and dries small molded parts made of rubber or plastic requiring a high degree of washing, for example, molded parts of various rubber stoppers or medical joints. The wash tank of the present invention is particularly effective in washing small molded parts such as a rubber stopper for a stopper used as a plug of a medicine phial for drug, liquid medicine or the like, a rubber part in a complicated shape having air vent holes such as a rubber stopper for fluid therapy, a plastic joint for a blood circuit or the like.
2. Related Art of the Invention
There have been known as generally performed conventional methods of washing small molded parts such as a rubber stopper for a medicine phial and the like, an agitation washing process where articles to be washed (hereinafter, referred to as washed objects) are only dipped in water, agitated and washed, a high pressure jet washing process where high pressure jet is blown, a pulsation washing process where washing is conducted by generating pulsation of air from a distributor having a double mesh structure (Japanese Patent Laid-open No. Sho 55-124580/1980), an ultrasonic wave washing process where washed objects are stored in an ultrasonic wave cleaner and washed by ultrasonic wave, or the like.
However, it is difficult to make flow a washing solution uniformly only by dipping washed objects in water or a liquid medicine and agitating them and therefore, there is a concern what wash specks are liable to cause, articles are damaged by a friction therebetween or exfoliated foreign objects are re-adhered to articles and a satisfactory washing effect has yet to achieve.
Further, even with a rubber stopper, when articles are provided with a complicated shape having air vents such as a rubber stopper for a half stopper or a rubber stopper for fluid therapy or the like, fine portions such as recessed portions or inner surfaces of small holes are difficult to wash. Even with the high pressure jet washing process, when a large amount of molded articles are washed in one operation, the jet stream is not made to blow uniformly to all of the articles and the uniform washing is difficult even with a single article since the degree of impingement of a jet stream is distributed and further, fine bubbles under the skin, a small amount of air adhered to a coarse surface or the like cannot be completely removed.
Furthermore, with respect to the ultrasonic wave washing process, when the washed object is an elastic article such as a rubber stopper, a sound wave is absorbed by the soft face whereby almost no washing effect is achieved. Also, with respect to the pulsation washing process utilizing the pulsation of air, a distributor for generating the pulsation of air is installed at a lower portion of a washer and therefore, when the specific weight of the washed object is small, the washed objects aggregate at upper portion of a washer whereby the washing effect is not sufficient and other washing system has to be used. As described above, it is the actual current situation that the satisfactory washing effect has not been achieved by any processes in washing various small molded articles made of rubber or plastic requiring a high degree of washability accordingly, a wash tank capable of efficiently washing objects by using a single tank and further capable of conducting sterilization and drying by using the same tank irrespective of a difference in materials of washed objects or magnitude of the specific weight has been desired. There have been various conventional rubber products the materials of which were brittle and where the rubber stopper per se was damaged by a jet stream and contamination frequently occurred. However, in recent times the rubber quality is improved and the jet stream washing becomes applicable. In view of the situation, the inventors have invented a washing device having a draft tube the upper end and the lower end of which are expanded for resolving the above-described problems and applied for a patent as Japanese Application No. Sho 57-229881/1982. According to the device, foreign objects are effectively exfoliated by circulating washed objects at the outside and the inside of the draft tube whereby the washed objects can uniformly be washed
One of the inventors invented a washing device where a cylindrical rotary drum is disposed in a sealed vessel to carry out further effective washing and applied for a patent as Japanese Application No. Sho 60-104736/1985. This device is a washing device having a cylindrical rotary drum in a sealed vessel which utilizes a jet stream generated in the rotary drum by a water jet pump.
However, the device described in Japanese Application No. Sho 57-229881/1982, has only the washing function and although the washing effect is significant when the specific weight of a washed object is large, a sufficient washing effect is not achieved when the specific weight is small. Meanwhile, with respect to the washing device described in Japanese Application No. Sho 60-104736/1985 sealing of rotary portions is indispensable since the rotary drum is disposed in the sealed vessel and the occurrence of foreign objects by dislodged abrasion of the rotating portions or invasion of foreign objects from a mechanical seal portion or the like is not totally dispensed with. Furthermore, as mentioned above, the device per se is complicated and the device is magnified whereby too much cost is imposed in manufacturing thereof. Accordingly, it is an object of the present invention to provide a highly practical wash tank of a compact type with no concern of occurrence or invasion of foreign objects where the washing effect is excellent irrespective of the magnitude of the specific weight of washed objects and the structure is simple and where also sterilization and drying can be conducted by using the same tank.


An X-ray apparatus and a mammographic X-ray apparatus are provided. The X-ray apparatus includes an X-ray beam generated by an X-ray source and a diaphragm. At least one LED is disposed as an indicator between the X-ray source and the diaphragm. The illuminating beam of the LED is directed in an undeflected fashion onto the X-ray field. The LED may be pivotable (swivable) out of the X-ray beam. The LED is mounted on a filter array that is mounted between the X-ray source and the diaphragm.

1. Field
The present embodiments relate to an X-ray apparatus, such as a mammographic X-ray apparatus. The apparatus includes an indicator.
2. Related Art
Generally, mammographic X-ray apparatuses have an indicator. Before the actual process of taking the X-ray images, the indicator projects an exemplary trace of an X-ray field on the surface of a patient body and/or on an object table. The X-ray field is monitored, for example, to assure that the correct diaphragm has been chosen. Conventionally, an incandescent bulb mounted laterally of the X-ray beam path is used. The beam of light from the incandescent bulb that extends perpendicular to the X-ray beam path, is deflected into the direction of the X-ray beam by a mirror disposed in the X-ray beam path. During the actual taking of the X-ray image, the mirror is folded out of the way of the beam path, or if it is radiotransparent, it stays in the beam path.
An X-ray apparatus of this kind is known from German Patent Disclosure DE 199 43 898 A1. According to DE 199 43 898 A1, an indicator in the form of laser diodes have been previously used, for example, for X-ray apparatuses used as aids in surgery. The indicators are mounted either on the X-ray detector or on the X-ray source. Accordingly, the region through which the X-radiation passes, for example, above the surface of the patient and/or the X-ray field on the surface of the patient, is visible (illuminated). The indicator is designed to be adaptable to the geometry of the X-ray beam, for example, the size of the opening angle, for instance by sending a signal for changing the aperture of the diaphragm onward to the indicator.

X-ray apparatus and mammographic x-ray apparatus with an indicator


Disclosed are: a stretched film obtained by uniaxially stretching a laminated film which comprises a base film and a polyvinyl alcohol resin layer laminated on one surface of the base film, wherein the base film has a multilayer structure of resin layers including two resin layers which comprise different resins from one another; a polarizing stretched film obtained by imparting polarizing performance to the stretched film; and a method for producing a polarizing plate using the polarizing stretched film. It is preferable that the resins constituting the above-described two resin layers show different phase transition temperatures from one another.

Polarizing plates are widely used as an element to generate polarization and as an element to detect polarization in a liquid crystal display device. Such polarizing plates in which a protective film composed of triacetylcellulose or the like is adhered to one surface or both surfaces of a polarizing film composed of a polyvinyl alcohol resin are conventionally used. Decrease in thickness and weight of polarizing plates has been recently requested in association with the increasing application of liquid crystal display devices to mobile devices such as notebook type personal computers and cellular phones, and further to large size televisions.
For example, JP 2000-338329-A, JP 2009-93074-A, JP 2009-98653-A and JP 2003-43257-A disclose a method for production of a polarizing plate by the use of a stretched film obtained by stretching a resin layer of polyvinyl alcohol resin formed on one surface of a base film comprising a single resin layer, as a method for producing a thin polarizing plate.
In producing a polarizing plate using the conventional stretched film as described-above, however, particularly if the draw ratio of the stretched film used is high, there is a problem of tearing of the film to the stretching direction when rolls, such as nip rolls, wind the film in dying the polyvinyl alcohol resin layer.
An object of the present invention is to provide a stretched film with a uniaxially stretched polyvinyl alcohol resin layer formed on one surface of a base film, the tearing of which to the stretching direction can be successfully restrained in a dying step of producing a polarizing plate or a polarizing stretched film. Another object of the present invention is to provide a polarizing stretched film and a polarizing plate by the use of the polarizing stretched film to which polarizing performance has been imparted.

Stretched film, polarizing stretched film, method for producing the stretched film, and method for producing the polarizing stretched film


A fiber optic laser conducting probe is used for photodynamic therapy. In this fiber optic laser conducting probe, an optical fiber has an end used for conducting a pulse laser beam. The laser beam is conducted through the optical fiber and irradiated from the end. A end tip is made of polyamide resin. The end tip has a hollow portion, and is attached to the end of the optical fiber such that the pulse laser beam can be irradiated through the end of the optical fiber, through the hollow portion and through the end tip.

The present invention relates to a fiber optic laser conducting probe used for therapy for an early cancer known as a photodynamic therapy.
Photodynamic therapy for an early cancer is performed, while observing the body cavity with an endoscope, by irradiating a laser beam in the amount as necessary against the affected part with a fiber optic laser and diffusion probe inserted through a forceps aperture of the endoscope. It is necessary to provide, at the extreme end of the probe, a tip capable of carrying out the irradiation of a laser beam in response to shapes of the body cavity, such as tubular organs such as the throat and cervical canal, and bag-like organs such as the stomach and lungs. For that purpose, methods heretofore proposed include U.S. Pat. No. 4,693,556 and U.S. Pat. No. 4,660,925, in which a tip is formed at the extreme end by an ultraviolet hardening resin containing a fine powder of quartz to provide a uniform diffusion of light; U.S. Pat. No. 4,676,231, in which a transparent liquid with suspended fine particles is put into a hollow transparent tip; and U.S. Pat. No. 4,649,151, which suggests in its specification and drawings that an epoxy resin mixed with light diffusion particles are coated on an internal surface of a hollow transparent tip.
Especially in case a pulse wave laser beam is used, an end tip formed of an inorganic material (Examples: quartz, sapphire, glass, etc.) tends to be easily cracked and broken, which is dangerous when the concentration and high densification of shock waves generated from a pulse laser occur in the tip. A situation tends to occur in a tip which uses hard plastics (Examples: polymethylmethacrylate resin, polystyrene resin, etc.) that causes the inner surface of the tip to be blackened to deteriorate the light irradiating performance.
On the other hand, a tip made of polyacetal resin known as Derlin (a trademark of Du Pont) has the possibility of generating formalin, which is injurious to the living body due to the thermal decomposition by the laser.
We have previously proposed, in Japanese Utility Model Application No. 75579/1993, an end tip made of polyolefin resin, particularly, polyethylene resin. No inconvenience occurred in the end tip according to this proposal when it was used under the conditions such that an excimer dye laser having a wavelength of 630 nm was caused to be incident as a pulse laser having an intensity of 4 mJ to 8 mJ/pulse at a frequency of 40 to 80 Hz from the fiber end so as to have an outgoing energy of 600 J in total from the end tip. However, in the end tip according to the above proposal, when it is used by causing the above-described laser to be incident from the fiber end with a laser intensity of 8 mJ/pulse or more at a frequency of 80 Hz or more, it was found that the tip becomes thermally softened, expanded or bent due to the rise in temperature caused by the heating of the laser, and a blackening phenomenon due to the generation of free carbon sometimes occurs.
It is natural that for relieving the pains of a patient during therapy or for increasing the efficiency of the medical treatment, an intense laser beam is rapidly applied to irradiate the same amount of irradiation in the shortest period of time. The end tip should be improved accordingly. On the other hand, the damage of end tip due to the rapid application of the laser beam, particularly damage that is injurious to the patient, should be completely avoided. The end tip for collecting or diffusing a pulse laser beam should be selected very carefully, unlike the end tip for a continuous wave laser.

Fiber optic laser conducting probe for photodynamic therapy


Gear-shaped resin sheets Sa are laminated such that tooth portions 2b are aligned in an axial direction, thereby preparing a spur gear-shaped net-shape body 4.

Conventionally, known is a method for producing a resin gear, which includes: cutting a resin sheet produced by sheet making into a gear shape; preparing a gear-shaped net-shape body by laminating a plurality of the gear-shaped resin sheets in an axial direction; and thereafter, molding the net-shape body by heat and compression (Patent Literature 1).
In accordance with this Patent Literature 1, for forming the above resin gear in a helical gear shape, teeth of the above gear-shaped resin sheets are gradually displaced and laminated, a helical gear-shaped net-shape body is prepared, and thereafter, the helical gear-shaped net-shape body is heated and compressed, so that a resin gear is molded (see paragraph 0037).
In addition, an apparatus for producing a resin gear in the above Patent Literature 1 is composed of upper and lower dies, which is so-called a cavity-core mold. For forming a resin gear in a helical gear shape, it is necessary to gradually displace and laminate teeth of the gear-shaped rein sheets in the lower die, and heat and compress them (see paragraphs 0031 and 0037).
Meanwhile, when a resin gear is prepared by laminating a plurality of resin sheets produced by sheet making in an axial direction, fibers are not entangled with each other in a direction of reinforcement fiber, and it is pointed out that resins are peeled off along this reinforcement fiber direction (Conventional Art of Patent Literature 2).

Resin gear, and method and apparatus for producing the same

Abstract: Tooth portions of the resin gear formed in a lower die 12 are pressed in a helical tooth-shaped molding space to deform the tooth portions 4a of the net-shape body 4 into a helical tooth tilted relative to the axial direction, and the direction of reinforcement fibers at the tooth portions 2b of the molded resin gear 1 is tilted relative to the axial direction.


An air pollution control system includes: a desulfurization device which removes sulfur oxides in a flue gas generated from a boiler; a cooler which is provided at the downstream side of the desulfurization device, decreases a flue gas temperature and enlarges a particle diameter of SO3 mist contained in the flue gas through cooling or heating the flue gas by a temperature adjustment means for adjusting a gas dew point temperature of the flue gas; and a CO2 recovery device which includes a CO2 absorber bringing CO2 in the flue gas into contact with the CO2 absorbent so as to remove CO2 therefrom and a regenerator recovering CO2 by dissociating CO2 from the CO2 absorbent and regenerating the CO2 absorbent, wherein the flue gas is cooled by a cooling unit so as to enlarge the SO3 mist in the flue gas.

In recent years, a greenhouse effect caused by CO2 has been pointed out as one of factors of global warming, and a countermeasure thereof is urgently needed in worldwide in order to keep a global environment. As the generation source, CO2 is generated in the action field of every person who consumes fossil fuel, and there is a tendency that the suppression of the emission is further strongly demanded. Thus, an air pollution control system and an air pollution control method for a power generation facility such as thermal power plant using a large amount of fossil fuel have been actively examined. Here, in the air pollution control system and the air pollution control method, a flue gas generated from an industrial facility such as a boiler or a gas turbine is brought into contact with an amine CO2 absorbent, CO2 in the flue gas is removed and recovered, and the recovered CO2 is stored without being discharged to the atmosphere.
As a process of removing and recovering CO2 from the flue gas by using the above-described CO2 absorbent, there is disclosed a CO2 recovery device including a process of bringing a flue gas into contact with a CO2 absorbent in a CO2 absorber (hereinafter, simply referred to as an "absorber") and a process of heating the CO2 absorbent (hereinafter, simply referred to as an "absorption solution") absorbed CO2 in the absorption solution regenerator (hereinafter, simply referred to as a "regenerator") so as to recover CO2 and regenerating the CO2 absorbent and to use the CO2 absorbent again in a circulation state in the CO2 absorber (for example, see Patent Literature 1).
In the CO2 absorber, for example, a counter-current contact occurs by using an amine CO2 absorbent such as alkanolamine, CO2 in the flue gas is absorbed to the CO2 absorbent by a chemical reaction (an exothermic reaction), and the flue gas from which CO2 has been removed is discharged to the outside of the system. The CO2 absorbent which absorbed CO2 is also referred to as a rich solution. The rich solution is boosted by a pump, is heated by a heat exchanger through a high-temperature CO2 absorbent (a lean solution) regenerated by recovering CO2 in a regenerator, and is supplied to the regenerator.

Air pollution control system and air pollution control method


A content management system (CMS) autonomically generates structure for a document when a synchronization rule references structure that does not exist in the document. A dynamic structure policy specifies at least one criterion that determines if and how the structure is autonomically generated. By autonomically generating structure in a document, a CMS administrator or CMS user (such as the author) is relieved of the manual task of generating the structure before the synchronization rule can be successfully processed. Once dynamically generated, the added structure may be auto-populated with dummy data or with default data specified in the autonomic structure policy.

1. Technical Field
This disclosure generally relates to content management systems, and more specifically relates to a content management system that autonomically generates structure during the processing of synchronization rules.
2. Background Art
A content management system (CMS) allows many users to efficiently share electronic content such as text, audio files, video files, pictures, graphics, etc. Content management systems typically control access to content in a repository. A user may generate content, and when the content is checked into the repository, the content is checked by the CMS to make sure the content conforms to predefined rules. A user may also check out content from the repository, or link to content in the repository while generating content. The rules in a CMS assure that content to be checked in or linked to meets desired criteria specified in the rules.
Known content management systems check their rules when content is being checked in. If the rule is satisfied, the content is checked into the repository. If the rule is not satisfied, the content is not checked into the repository. Known content management systems may include rules related to bursting, linking, and synchronization. Bursting rules govern how a document is bursted, or broken into individual chunks, when the document is checked into the repository. By bursting a document into chunks, the individual chunks may be potentially reused later by a different author. Linking rules govern what content in a repository a user may link to in a document that will be subsequently checked into the repository. Synchronization rules govern synchronization between content and metadata related to the content. For example, a synchronization rule may specify that whenever a specified CMS attribute is changed, a particular piece of XML in the content should be automatically updated with that attribute's value.
Known content management systems may not process a synchronization rule correctly if the synchronization rule identifies one or more structures that do not exist in a document. Thus, in order for a new synchronization rule that defines new structures to be correctly processed, first the CMS administrator or a CMS user (such as the author of the document) has to manually add the new structures to the document. Once the document has the new structure, the new synchronization rule that references the new structure may be properly processed. Without a way to automate some of the manual tasks normally performed by a CMS administrator, the computer industry will continue to suffer from the manual tasks that must be performed when a new synchronization rule that references new structures needs to be processed.

This patent is subject to a terminal disclaimer.

Autonomic generation of document structure in a content management system

International Business Machines Corporation


A support stand for positioning a precision gauge for checking the dimensions of an article. The base is stable having three supporting feet and being heavier than many such support bases. The base is tapered with finger grooves to fit well into the user's hand and provides an adjustment screw which rotates about a horizontal axis so reaction forces are directed downwardly into the support plate rather than creating a shearing, destabilizing force. The adjustment screw has as large a diameter as practical to reduce the magnitude of the tangential force needed to produce rotation and its rotation reacts a nub against the substantially vertical support post to tilt it, and the precision gauge supported thereby. An L-shaped bracket can be inverted to provide increased flexibility in measuring different size articles. Squareness checking rails are provided on the front and back surfaces to enhance the flexibility of using this support stand.

In tool and machine shops, precision gauges are used to verify that a machined article has been manufactured within the desired tolerances. A height gauge is used to verify that the vertical dimension is what it ought to be. A precision gauge is mounted on a support stand and positioned upon a granite surface plate that has been polished to have a surface flatness within millionths of an inch. Gauge blocks which have been ground and lapped to a particular dimension are used to calibrate the height gauge and the measurement transferred to the machined article to verify that it is within tolerance.
A number of support stands are available for supporting a precision gauge for comparing an article to a known standard as part of this quality control check in a machining or assembly operation. These supports typically have a vertical post to which a support arm is attached by a bracket. The support arm mounts the precision gauge and can be moved up and down the post for rough positioning of the gauge relative to the gauge block. Typically, a fine adjustment is available to position the gauge finger on the top of the gauge block. A rotatable dial on the gauge permits the force with which the gauge finger engages the gauge block to be zeroed out so the gauge finger is set at the precise height of the gauge block. The height gauge support stand can then be slid over the gauge plate surface to position the gauge finger above a machined article to determine if it is within the desired tolerance range. If several articles or dimensions on the same article are to be measured, typically a plurality of height gauge supports will be utilized so that once set, the gauge can be left in its adjusted position and simply repeatedly used to measure sequential articles. Most such gauge supports have a machined surface that may be brought into contact with a lateral face of the article to check its squareness.
One such support is described in U.S. Pat. No. 4,284,257 issued to David Murkens. This support has a split plate design with the upper and lower halves interconnected along one end face by a spring plate bolted to each half. Precision adjustment is effected by rotating a knob about a vertical axis pushing against the lower plate in order to tilt the upper plate with a vertical support post and the gauge attached. Due to the large number of parts, this design is expensive to manufacture and assemble. Also, its operation requires two hands, one to steady the stand and one to rotate the adjustment knob. In addition, the torquing of the adjustment screw about the vertical axis can cause the entire support to turn the article engaging tip of the height measuring gauge off the workpiece being measured. This can slow down the measuring process and aggravate the workman.
A second known device is available from Starn Tool and Manufacturing Company. This gauge support has a machined longitudinal beam that slides inside an outer gauge support block. The longitudinal beam has three different dimensions and an aperture which must be machined from a solid block of material and the support block must have a precision internal opening machined, as well. An adjustment screw extends vertically through a portion of the support block and engages an end of the longitudinal beam in order to permit tilting adjustment of the beam and the post it supports. This height measuring gauge suffers from the same problems associated with the Murkens device: it is expensive to manufacture, rotation of the adjustment knob requires two hands and torques the entire support about a vertical axis, which can cause movement of the article engaging finger.
The present invention overcomes the difficulties of the prior art by providing an adjustment screw that rotates about a horizontal axis on a front portion of the base, where it is out of the way. The base of the support stand is tapered to fit easily in the hand of the worker with grooves on each side for the fingers and thumb. The base can be gripped between the thumb and middle fingers while the index finger is used to rotate the adjustment screw permitting one-handed operation. In this manner, the force is generally down into the surface plate increasing resistance to movement of the base rather than creating a shear force between the surface plate and base tending to cause movement. Also, the adjustment knob can be rotated by pulling or pushing the periphery of the knob toward the thumb or middle finger of the hand gripping the base such that the component of the force that is not reacted into the support is offset by an opposing force from the thumb or middle finger.
The base is heavier than many others which are available, making it more stable. Further, the base has three point contact with the surface plate which also improves stability since three point contact will not rock, although four point contact might. In addition, three point contact reduces friction with the plate making it easier to move over the surface plate when being positioned relative to the workpiece.
The thread pitch on the adjustment knob screw is finer than most adjustment screws making the positioning of the gauge finger easier to accomplish. The fact that the adjustment screw is larger in diameter makes it easier to turn since the point at which the force is applied is further from the rotational axis increasing the length of the moment arm which reduces the magnitude of the tangential force required to produce rotation. Squareness checking rails are provided on both the front and rear faces of the base to enhance the utility of the device.
Various other features, advantages and characteristics of the present invention will become apparent to one of ordinary skill in the art after a reading of the following specification.


A semiconductor device is inspected and cleaned by applying a vacuum to the area in which the semiconductor device is positioned. Micro-sized particulates that are brushed off the semiconductor device during cleaning are drawn off by the vacuum.

At the present time, certain semiconductor devices, such as silicon microchips, filmed micro-channel plates, and other similar wafer devices, are inspected and cleaned of micro-sized particulates in "clean-room" environments. It has been found that, even in such an environment that is thought to be ideal for cleaning such devices, particulates that are to be cleaned continue to contaminate the device to an unacceptable extent. When, for example, an operator brushes contamination particulates from a glass wafer, the contamination particulates can become airborne or temporarily attached to the brush being used to clean the device. The particulates can then settle again on the device or be drawn from the brush to the device by static charge.

Apparatus and method for inspecting and cleaning semiconductor devices


A method for handling discarding of a sequence of service data units in a communications system is disclosed. The sequence of service data units includes at least a last discarded service data unit (SDU). When a protocol data unit (PDU) containing a length indicator of the last discarded SDU contains no new SDUs, the method includes creating a move receiving window super field (MRW SUFI), setting a NLENGTH field of the MRW SUFI to 0, setting a last sequence number move receiving window field (SN_MRWLENGTH) to a sum of one plus a sequence number (SN) of the PDU containing the length indicator of the last discarded SDU, and issuing the MRW SUFI.

1. Field of the Invention
The present invention relates to a wireless communications system, and more particularly to a method for discarding data segments in a wireless communications system.
2. Description of the Prior Art
New uses are constantly being found for wireless communications. Initially limited to voice communications, packetized data has opened the field to cellular modems, camera phones, fixed-wireless transceivers for high-speed networking, and myriad other uses. The field is growing rapidly and requires sophisticated protocols to handle the increasing amount of data being transmitted. The Universal Mobile Telecommunications System (UMTS) specified by the 3rd Generation Partnership Project (3GPP™) is an example of such a new communications protocol. The 3rd Generation Partnership Project (3GPP) specification, TS 25.322 V6.1.0 (2004-06) Radio Link Control (RLC) protocol specification (referred to hereinafter as 3GPP TS 25.322), included herein by reference, provides a technical description of data transmission control protocols thereof. UMTS utilizes a three-layer approach to communications. The three-layer protocol has a first layer, the physical transport layer; a second layer, where data is packetized, collated, and organized; and a third layer, which interfaces between the second layer and applications generating or using the data.
The packetization and collation processes are designed to handle missing data segments, due to noise in transmission or other errors, by triggering a retransmission procedure. When a collation cannot be fulfilled by the retransmission procedure due to a protocol error, a reset procedure may be initiated to recover the transmission from the protocol error. The reset procedure can cause large delays as all the state variables are reset and the transmission entity is started over from the beginning. These problems occur primarily in the second (packet control) layers.
Please refer to FIG. 1, a block diagram of the three layers in such a communications protocol. In a typical wireless environment, a first station 300 is in wireless communication with one or more second stations 400. An application 330 on the first station 300 composes a message 310 and has it delivered to the second station 400 by handing the message 310 to a third layer interface 320. The third layer interface 320 may also generate some third layer signaling messages 320a for the purpose of controlling third layer operations. The third layer interface 320 delivers either the message 310 or the third layer signaling message 320a to a second layer interface 360 in the form of second layer service data units (SDUs) 340. The second layer SDUs 340 may be of any length. The second layer interface 360 composes the SDUs 340 into one or more second layer protocol data unit(s) (PDU) 380. Each second layer PDU 380 is of a fixed length, and is delivered to a first layer interface 390. Note that the fact that variable length SDUs are transported in fixed length PDUs generates issues that are highly relevant to the present invention, and these issues are discussed in more detail below. The first layer interface 390 is the physical layer, transmitting data to the second station 400. The transmitted data is received by the first layer interface 490 of the second station 400 and reconstructed into one or more PDUs 480, which is/are passed up to the second layer interface 460. The second layer interface 460 receives the PDU(s) 480 and builds up one or more second layer SDU(s) 440 from the PDU(s) 480. The second layer SDU(s) 440 is/are passed up to the third layer interface 420. The third layer interface 420, in turn, converts the second layer SDU(s) 440 back into either a message 410, which should be identical to the original message 310 that was generated by the application 330 on the first station 300, or a third layer signaling message 420a, which should be identical to the original signaling message 320a generated by the third layer interface 320, and which is then processed by the third layer interface 420. The received message 410 is passed up to an application 430 on the second station 400.
In order to detect missing data, the protocol relies on the collation of PDUs in the second station's 400 second layer 420 to notice that a PDU has not been received and to send a request for retransmission through the first layer 490 to the first layer 390 of the first station 300.
Please refer to FIG. 5, which illustrates a typical sequence of PDUs containing SDUs. In this example, two SDUs, SDU1 and SDU2, each of length 80 octets, are packetized into four PDUs P0, P1, P2, P3 each of length 64 octets. Each PDU contains a header, respectively P0h, P1h, P2h, P3h, which is two octets long, leaving 62 octets for the contents of the PDUs. Each header contains, among other data, a sequence number (SN), which increases sequentially in each PDU transmitted, and a flag indicating whether or not the PDU has a length indicator (LI), which indicates the position of the last byte of data of a SDU. The flag is located at the last bit of the header. If the flag is set to 1, then the PDU contains a LI structure of one octet, with the first seven bits indicating the length of the data to which it refers and the eighth bit being a flag indicating whether this is the last LI in the PDU. PDU P0 has the SN of zero (0), and the flag indicates that there is no LI. The data 10a is thus entirely from a single SDU. PDU P1 has SN equal to 1, and its flag set to 1 indicates that the next octet is a LI structure, which contains a LI field and a one-bit flag. The first LI field 10L has a value of eighteen (18) followed by a flag indicating another LI structure to follow; PDU P1 then has a second LI field P1pL with a value of 127 (all 1's for the 7 bits of the second LI) followed by a flag set to 0 indicating that the second LI is the last LI in the PDU. The first eighteen data bytes of this PDU, following the two LI structures, are the remainder of the data 10b for SDU1. The special value (127) of the second LI indicates that the rest part of the PDU P1p is a padding, which is padded with arbitrary value to keep the length of the PDU P1 fixed and shall be neglected. PDU P2 has the SN of 2, and the flag indicates that there is no LI. The data 12a is thus entirely for a single SDU. Similarly, PDU P3 has SN of 3, and its flag set to 1 indicates that it contains a LI structure. The LI 12L has a value of 18 and a flag indicating a second LI structure follows; PDU P3 then has an LI field P3pL with a value of 127 followed by a flag set to 0. Thus, the first eighteen data bytes of this PDU 12b, following the two LI structures, are the remainder of the data 10b for SDU2. The rest part P3p is padding.
Please refer to FIG. 6, which illustrates another typical sequence of PDUs containing SDUs. In this example, two SDUs, SDU1 and SDU2, each of length 80 octets are packetized into three PDUs Q0, Q1, Q2 each of length 64 octets. Each PDU contains a header, respectively Q0h, Q1h, Q2h, Q3h, which is two octets long, leaving 62 octets for the contents of the PDUs. PDU Q0 has the SN of zero (0), and the flag indicates that there is no LI. The data 14a is thus entirely from a single SDU SDU1. PDU Q1 has a header Q1h with SN equal to 1 and its flag set to 1 indicating that a LI structure follows the header Q1h. The LI field 14L has a value of 18 followed by a flag set to 0 indicating no more LIs; the first eighteen data octets 14b of this PDU are thus the remainder of SDU1, and the remaining forty-three data octets 16a are from the next SDU, SDU2. PDU Q2 has a header Q2h with SN equal to 2 and its flag set to 1 indicating that a LI structure follows the header Q2h. The Li field 16L has a value of 37 followed by a flag set to 1 indicating another LI follows. The second LI has a value of 127 followed by a flag set to 0 indicating no more LIs. The first thirty-seven data octets 16b of the PDU are the remainder of SDU2, and the remaining octets are padding Q2p to be neglected.
Please refer to FIG. 7, which illustrates a third typical sequence of PDUs containing SDUs. In this example, two SDUs, SDU1 of length 62 octets and SDU2 of length 80 octets, are packetized into four PDUs R0, R1, R2 and R3, each of length 64 octets. Each PDU contains a header, respectively R0h, R1h, R2h, R3h, which is two octets long, leaving 62 octets for the contents of the PDU. PDU R0 has the SN of zero (0), and the flag indicates that there is no LI. The data 18a is thus entirely from a single SDU. PDU R1 has SN equal to 1, and its flag set to 1 indicates that it contains a LI structure. The LI 18L has a value of zero (0) followed by a flag set to 1 indicating another LI to follow; it then has an LI field R1pL with a value of 127 followed by a flag set to 0 indicating that it is the last LI in the PDU. The special value (0) of the first LI indicates that the previous PDU R0 was exactly filled with the last segment of a SDU, SDU1, and there is no LI field that indicates the end of the SDU in the previous PDU R0. Thus, the rest part R1p of PDU R1 is a padding part to be neglected. PDU R2 has the SN of 2, and the flag indicates that there is no LI. The data 20a is thus entirely from a single SDU, SDU2. PDU R3 has a header R3h with SN of 3 and its flag set to 1 indicating that a LI structure follows the header R2h. The LI field 20L has a value of 18 followed by a flag set to 1 indicating another LI to follow; it then has an LI field R3pI with a value of 127 followed by a flag set to 0 indicating that there are no further LI fields. Thus, the first eighteen data bytes of this PDU, following the two LI structures, are the remainder of the data 20b for SDU2. The remaining part R3p of this PDU is padding to be neglected.
In the prior art, the method for discarding an SDU is as follows. Please refer to FIG. 2, FIG. 3, and FIG. 4, which are flowcharts of the prior art method of discarding SDUs. These steps are explained below:
Step 100: Trigger a new Move Receiving Window (MRW) procedure. The sender indicates that at least one SDU is to be discarded.
Step 102: Set up a STATUS PDU with a MRW superfield (SUFI). Create a PDU structure and populate its basic fields.
Step 104: Determine whether "send MRW" is configured for this RLC entity. When true, proceed to step 110. When not true, proceed to step 106.
Step 106: Set the STATUS PDU to include the last SN_MRWi field for the last discarded SDU.
Step 108: Optionally set the STATUS PDU to include other SN_MRWi fields for other discarded SDUs, and proceed to step 116 (marked by "A", in FIG. 3).
Step 110: Check whether there are more than 15 discarded SDUs, which is the largest number of SDU SN_MRWi fields that can fit in the STATUS PDU. When more than fifteen SDUs are being discarded, proceed to step 112. When fifteen or fewer SDUs are being discarded, proceed to step 114.
Step 112: Set up the MRW SUFI for the first fifteen discarded SDUs.
Step 114: Include one SN_MRWi field for each corresponding discarded SDU. Proceed to step 116 (marked by "A", in FIG. 3).
Step 116: Check whether the last discarded SDU ends in a PDU which contains the LI of the last discarded SDU and contains no new SDUs. When true, proceed to step 118. When false, proceed to step 120.
Step 118: Set the last SN_MRWi field (SN_MRWLENGTH) to be the sum of one plus the SN of the PDU at which the last discarded SDU ends, and set NLENGTH to zero. Proceed to step 122 (marked by "B" in FIG. 4).
Step 120: Set the last SN_MRWi field (SN_MRWLENGTH) to be the SN of the PDU which contains the LI of the last discarded SDU, and set NLENGTH to be the number of LIs corresponding to discarded SDUs within the PDU which contains the LI of the last discarded SDU. Proceed to step 122 (marked by "B" in FIG. 4).
Step 122: Set each of the other SN_MRWi fields to be the SN of the AMD PDU containing the LI of the corresponding discarded SDU
Step 124: Check whether there is only one SN_MRWi field and if its corresponding discarded SDU extends above the configured transmission window. When true, proceed to step 126. When false, proceed to step 128.
Step 126: Set LENGTH to zero, and proceed to step 130.
Step 128: Set LENGTH to the number of SN_MRWi fields, and proceed to step 130.
Step 130: Submit the STATUS PDU with MRW SUF1 for transmission.
Step 132: Finish (exit procedure).
please refer to FIG. 5 with regard to the above steps, as well as FIG. 2, FIG. 3, and FIG. 4. When an SDU discard procedure is initiated to discard SDU1, a MRW procedure is triggered at step 100 (shown in FIG. 2). The method sets up a STATUS PDU with MRW SUF1 in step 102. Since only one SDU is being discarded, the method will produce the same results whether step 104 chooses to go to step 106 or step 110. When "Send MRW" is not configured, step 106 includes the SN_MRW1 field in the MRW SUFI for SDU1, and step 108 is ignored since there are no more SDUs being discarded. When "Send MRW" is configured, step 110 proceeds to step 114 since only one SDU is being discarded, and step 114 includes the SN_MRW1 field in the MRW SUFI for SDU1. Both paths then converge again at step 116 (shown in FIG. 3). In step 116, the last discarded SDU, SDU1, ends in PDU P1, and PDU P1 contains the LI 10L, and contains no new SDUs after SDU1 since its remainder is filled with padding P1p. Therefore, the method proceeds to step 118, where the last SN_MRWi field, SN_MRWLENGTH, is set to the sum of one plus the SN of PDU P1, or the value 2, since PDU P1 has an SN of 1. The method then proceeds to step 122 (shown in FIG. 4), where since there are no more discarded SDUs, nothing is done. At step 124, depending on the actual position of the transmission window, the method either goes to step 126 or step 128, where the LENGTH field of the MRW SUFI is filled in with either the value 0 or the value 1 respectively. Finally, at step 130, the method is ready to transmit the just-created STATUS PDU with MRW SUFI, and the method finishes at step 132.
Next, please refer to FIG. 6 with regard to the above steps, as well as FIG. 2, FIG. 3, and FIG. 4. When an SDU discard procedure is initiated to discard SDU1, a MRW procedure is triggered at step 100 (shown in FIG. 2). The method sets up a STATUS PDU with MRW SUFI in step 102. Since only one SDU is being discarded, the method will produce the same results whether step 104 chooses to go to step 106 or step 110. When "Send MRW" is not configured, step 106 includes the SN_MRW1 field in the MRW SUFI for SDU1, and step 108 is ignored since there are no more SDUs being discarded. When "Send MRW" is configured, step 110 proceeds to step 114 since only one SDU is being discarded, and step 114 includes the SN_MRW1 field in the MRW SUFI for SDU1. Both paths then converge again at step 116 (shown in FIG. 3). In step 116, the last discarded SDU, SDU1, ends in PDU Q1, and PDU Q1 contains the LI 14L, and contains a new SDU, SDU2, which has its first data segment 16a. Therefore, the method proceeds to step 120, where the last SN_MRWi field, SN_MRWLENGTH, is set to the SN of PDU Q1, or the value 1, since PDU Q1 has an SN of 1. The method then proceeds to step 122 (shown in FIG. 4), where since there are no more discarded SDUs, nothing is done. At step 124, depending on the actual position of the transmission window, the method either goes to step 126 or step 128, where the LENGTH field of the MRW SUFI is filled in with either the value 0 or the value 1 respectively. Finally, at step 130, the method is ready to transmit the just-created STATUS PDU with MRW SUFI, and the method finishes at step 132.
For a third example, please refer to FIG. 7 with regard to the above steps, as well as FIG. 2, FIG. 3, and FIG. 4. When an SDU discard procedure is initiated to discard SDU1, a MRW procedure is triggered at step 100 (shown in FIG. 2). The method sets up a STATUS PDU with MRW SUFI in step 102. Since only one SDU is being discarded, the method will produce the same results whether step 104 chooses to go to step 106 or step 110. When "Send MRW" is not configured, step 106 includes the SN_MRW1 field in the MRW SUFI for SDU1, and step 108 is ignored since there are no more SDUs being discarded. When "Send MRW" is configured, step 110 proceeds to step 114 since only one SDU is being discarded, and step 114 includes the SN_MRW1 field in the MRW SUFI for SDU1. Both paths then converge again at step 116 (shown in FIG. 3). In step 116, the last discarded SDU, SDU1, ends in PDU R0, which does not contains the LI 18L of the last discarded SDU, SDU1. Therefore, the method proceeds to step 120, where the last SN_MRWi field, SN_MRWLENGTH, is set to the SN of PDU R1 which contains the LI 18L of the last discarded SDU, SDU1, or the value 1, since PDU R1 has an SN of 1. The method then proceeds to step 122 (shown in FIG. 4), where since there are no more discarded SDUs, nothing is done. At step 124, depending on the actual position of the transmission window, the method either goes to step 126 or step 128, where the LENGTH field of the MRW SUFI is filled in with either the value 0 or the value 1 respectively. Finally, at step 130, the method is ready to transmit the just-created STATUS PDU with MRW SUFI, and the method finishes at step 132.
The current method therefore incorrectly sets the MRW SUFI to discard PDU R0 only, moving the receiving window to start at PDU R1. The receiving station or the second station 400 in FIG. 1 will wait to receive PDU R1, which is discarded in the transmitting station or the first station 300 in FIG. 1. A reset procedure will be initiated later.
As seen in the third example, a key problem of this method is that it sometimes fails to discard a PDU when it should. This causes a reset procedure to be triggered occasionally in the normal course of discarding SDUs. As these reset procedures waste potentially large amounts of bandwidth, an improved method for discarding SDUs is clearly necessary.

Enhanced SDU discard procedure for a special data segmentation in a wireless communications system


A semiconductor device including a bias voltage generator formed from a junction field effect transistor (JFET). The JFET includes a control gate terminal and a first and a second source/drain terminal. The first and second source/drain terminals can form a first terminal of a p-n junction and the control gate terminal can form a second terminal of the p-n junction. The first terminal of the p-n junction can be provided with a first potential. The second terminal can be left essentially floating to provide a bias voltage. A bias receiving circuit can receive the bias voltage. The bias receiving circuit can be in close proximity on the semiconductor device to the bias voltage generator.

Semiconductor devices use bias voltages for many applications. Bias voltages and/or reference voltages can be used in many electronic circuits including both analog and digital circuits. As feature sizes in semiconductor devices are decreased, power supply voltages can be decreased to prevent devices from breaking down due to excessive electric fields. However, bias voltages are still necessary and can consume a significant amount of circuit area.
Furthermore, bias voltages may be generated on a device and then routed to circuits that are not located near the bias voltage generator. Thus, the bias voltage routing may consume even more critical space on the semiconductor device.

Semiconductor device including a bias voltage generator


Some aspects disclosed herein are directed to, for example, a system and method comprising a client device receiving an input of at least a portion of a message. The client device may display, on a display of the client device, the at least the portion of the message. The client device may transmit, to a server device, the at least the portion of the message for display via a second client device. The client device may receive, from a user of the client device or a user of the second client device, a request to generate a marker for the at least the portion of the message. In response to the receiving the request to generate the marker, the client device may determine, based on a lexicon, a name for the marker for the at least the portion of the message. The client device may store, at a storage location, the name for the marker for the at least the portion of the message, an identifier for the at least the portion of the message, and an association between the name for the marker for the at least the portion of the message and the identifier for the at least the portion of the message.

Text from a messaging session between users may be displayed in a chat conversation window or browser. It may, however, be difficult to find specific content from the messaging session or to scroll up through lengthy messages or conversations. Currently, excessive data storage space may be used to store numerous lengthy messaging sessions between many different users. Moreover, existing processing resources may be overburdened when searching for specific content from current or previous messaging sessions.

Processing system for intelligently linking messages using markers based on language data


A processor architecture provides for at least two simultaneous execution contexts, hardware resources having at least one execution unit, an instruction scheduler, an interrupt controller, and memory management means, and a given privileged context from among the simultaneous execution contexts that, in a privileged mode of an operating system, commands the other processor contexts by reading from and writing to registers of other contexts.

1. Field of the Invention
The present invention relates to techniques for processing several simultaneous threads (known as "Simultaneous Multi-Threading", or SMT) that are implemented in processor architectures having several execution contexts (multicontext processor), such as in processor cores having several simultaneous execution contexts (known as "Simultaneous Multi-Threaded processors", or SMTs).
2. Description of the Related Art
Over the last ten years, research has been carried out to improve the paralleling of threads and the use of execution units in a processor core. Simultaneous multithreading is a well-known technique in the field of single-processor architectures, (see Patent Application US 2002/0083297) or multiprocessor architectures (see Patent Application US 2003/0088610). It makes it possible to increase the processing speed of a microprocessor, whether it has a superscalar or other architecture (that is to say whether it has several or just one execution unit). A thread is a component of a process corresponding to a sequence of elementary operations. In a processor having several simultaneous execution contexts, a thread is executed in one of the contexts of the processor. An execution context therefore designates the state of all the registers of the processor when it is allocated to a thread.
An execution context typically comprises nonprivileged registers, that is to say ones that can be accessed by the applications in user mode, and privileged registers, that is to say ones that can be accessed by the operating system (or OS) in privileged mode only. These latter comprise, in particular, configuration registers, such as the base address register of the translation table of a memory management unit (or MMU).
In a conventional SMT processor core architecture, all the simultaneous execution contexts have the same rights of access to the peripherals, to the memory, and to the registers, etc. This is why such an architecture is said to be symmetric in what follows. In fact, a process which is executed in the privileged mode of any one of the simultaneous execution contexts possesses full control of the hardware resources of the processor and can therefore in practice divert the system from its normal use.
However, a requirement has recently appeared for the secure processing of sensitive information such as a user's bank identification data (for example a bank account number or a credit card code). A requirement exists to be able to continue to execute a pre-existing operating system (known as a "Legacy OS"), such as Windows® or Linux®, and its associated application programs, while being able to oversee them in such a way that they do not jeopardize the integrity and the security of the system if a hacker were to take control of these OSs by exploiting their numerous flaws.
A trend observed in the state of the art consists in favoring an essentially hardware approach to achieve a certain level of security. According to such an approach, additional hardware make it possible to encapsulate and therefore to protect a secure domain inside the processor by effecting a hardware separation between a nonsecure mode and a secure mode. This approach is used, to mention but a few, in the Nomadik® family of multimedia application processors from STMicroelectronics, in products based on the Trustzone™ technology from ARM, or in those based on the NGSCB ("Next Generation Secure Computing Base") technology from Microsoft®.

Privileged execution context restricting use of hardware resources by other execution contexts