A process for decontaminating radioactive material comprises the step of contacting the material with a dissolving composition to dissolve the contaminants in the material, said composition comprising a dilute solution of about 0.05 molar ethylene diamine tetraacetic acid, about 0.1 molar carbonate, about 10 grams per liter hydrogen peroxide and an effective amount of sodium hydroxide to adjust the pH of the composition to a pH from about 9 to about 11. Also included are the steps of separating the dissolving composition containing the dissolved contaminants from the contacted material and recovering dissolved contaminants from the dissolving composition that has been separated from the material. A composition for dissolving radioactive contaminants in a material, comprising a dilute solution having a basic pH and effective amounts of a chelating agent and a carbonate sufficient to dissolve radioactive contaminants is also provided.

Environmental contamination with radioactive materials is a common problem. The problem may occur as a result of mining operations, such as for uranium, or contamination due to operation of nuclear facilities with inadequate environmental controls, or from the disposal of radioactive wastes. Alternatively, contamination may occur as a result of dispersion of uranium billets which have been used as a high density material in military or civil applications as a result of warfare or civil accident.
Mining operations have established practical and economic methods for the economic recovery of some radioactive elements from contaminated materials. The objective of mining, however, is usually the economic recovery of materials and secondary waste is rarely the major issue. In environmental clean-up, the economic objective is to complete effective clean-up with minimum secondary waste at minimum cost, and the value of recovered radioactive substances is of secondary importance. Techniques and chemicals which would not be economical or appropriate for mining applications may become practical for environmental clean-up.
It is well established that radioactive elements can be recovered from environmental materials by mechanically washing with water with or without surface active additives. However, such procedures are generally limited to the mechanical separation of solids, and will not remove contaminants that are chemically bound to the solid phase.
There are established chemical methods for dissolving insoluble radioactive contaminants in concentrated solvents, such as strong acids, in a process known as acid leaching. Such procedures are effective, but are disadvantageous if the spent concentrated solution ultimately becomes waste. In many cases, the concentrated solvents themselves are hazardous in addition to containing the radioactive contaminant that the process is designed to concentrate. The acid leaching and other processes using concentrated solvents to dissolve the radioactive contaminant have the further disadvantage of also dissolving other contaminants that the process was not designed to remove, such as nonradioactive metals.
In the decontamination of internal surfaces of nuclear reactor circuits, early processes involved washing with concentrated chemical solutions to dissolve contaminants to yield a concentrated solution containing the contamination. The processing of these waste solutions was found to be difficult and inconvenient and resulted in them becoming waste and requiring disposal. The technology has now progressed to allow the recovery of radioactivity, typically by ion exchange, in a dilute acidic recirculating system. These solutions, being dilute and acidic, do not contain carbonate and are not particularly useful or appropriate for dissolving actinide elements because they do not form soluble complexes with the actinide elements.
In reactor decontamination processes, it has been established that certain organic reagents can be used to dissolve contamination and yield it to an ion exchange resin in a recirculating process in such a way that the organic reagent is continuously re-used. Examples of solutions used in acidic reactor decontamination processes are vanadous formate, picolinic acid and sodium hydroxide. Other processes typically use mixtures of citric acid and
oxalic acid. These reactor decontaminating solutions have the disadvantage of not being capable of being used in a single one time application to dissolve actinides, radium, and certain fission products, such as technetium.
Previous reactor decontaminating solutions do not contain carbonate and are acidic, dissolving the iron oxides of the radioactive elements commonly found in contaminated reactor circuits. This nonselective metal dissolving capacity is a disadvantage of the acidic solutions and makes them unsuitable for decontamination of material such as soil that contains iron and other metals that are not intended to be recovered. Another disadvantage of acidic solutions is that materials such as concrete or limestone are subject to damage or dissolution in an acidic medium. Also, in dealing with previously known washing solutions for treating soil, these solutions contain too many nonselectively dissolved contaminants preventing subjection of the solution to recovery of contaminants and recirculation of the solution to accomplish further decontamination.
It has been established that uranium and transuranic radioactive elements can be dissolved in concentrated acidic (pH<1) chemical systems. The acidity poses difficulties as discussed above. Uranium and sometimes thorium are recovered in mining operations in a concentrated basic medium containing carbonate. The use of concentrated solutions is motivated by the need to dissolve materials at a rate economic for mining operations, and such solutions are not particularly suitable where avoidance of secondary waste is of primary concern. There are also references that suggest that uranium and plutonium can be dissolved in a dilute basic solution containing carbonate, citrate (as a chelating agent) and an oxidizing or reducing agent. Such solutions are not, however, suitable for the recovery of radium/barium sulfate because they do not form soluble complexes from barium sulfate.

Process for decontamination of radioactive materials


A device for treating forage, intended to accelerate the drying and comprising a rotor which is rotated about an axis and includes a support and at least one conditioning element. The conditioning element includes at least one active part which is used to work the forage, a first connecting part which is used to connect the conditioning element to the support via a first connection, and a second connection which connects the conditioning element to the support if the first connection breaks.

Document FR 2 440 145 describes a mower comprising a cutting mechanism intended to cut a standing product, for example grass. To do this, the cutting mechanism has four discs arranged in a transverse line of the said-mower and driven in rotation about a respective vertical axis.
This known mower also comprises a treatment device intended to reduce the time taken for the cut forage to dry. To do this, the forage treatment device comprises a rotor arranged behind the discs and driven in rotation about a horizontal axis. This rotor consists of conditioning elements and of a support. Each conditioning element comprises, at one of its ends, a connecting part. The connecting part allows the corresponding conditioning element to be connected pivotally to the said support by means of an articulation the axis of which is parallel to the axis of rotation of the said rotor. Because of the centrifugal force generated by the rotation of the said support, the conditioning element during work extends in a substantially radial direction.
Thus, during work, the forage coming from the cutting mechanism is carried, by an active part of the conditioning element, along a conditioning sheet to finally be ejected to the rear of the said mower. The passage of the forage against the said conditioning sheet causes a breaking-up of the stalks of the forage that encourages rapid drying of the latter. The brochure "Faucheuses-Conditionneuses frontales FC 15 280F / FC 313F Lift Control" [Front-mounted mower-conditioners FC 280F/FC 31 3F-lift control] published by the Applicant company, discloses another mower equipped with a forage treatment device. In that document, the said forage treatment device also comprises a rotor driven in rotation about a horizontal axis. This rotor consists of a support and of V-shaped conditioning elements. Each conditioning element this time is connected rigidly to the support by a central connecting part. The two ends of the V-shape extend in a radial position to form an active part.
During work, the rotational frequency of such rotors is generally between 600 and 1 000 revolutions per minute. As a result, if the connection between the support and the conditioning element should break, the latter element is ejected from the rotor violently by the centrifugal force. The conditioning element thus ejected constitutes a projectile travelling at relatively high speed. This projectile may damage other parts of the forage treatment device, particularly the conditioning sheet. Of far greater concern, such a projectile may also be dangerous to anybody close to the forage treatment device.

Device for treating fodder and reaping machine which uses such device for treating fodder


A single reservoir contains brazing filler metal. A first electromagnetic induction pump extends vertically along a vertical plate portion at a workpiece inlet side. A second electromagnetic induction pump extends vertically along a vertical plate portion at the workpiece outlet side. Heaters for melting the brazing filler metal are disposed between the first electromagnetic induction pump and the second electromagnetic induction pump. Each electromagnetic induction pump has a first iron core having an induction coil wound therearound disposed at the outer side of a vertical plate portion at the workpiece inlet side or the workpiece outlet side respectively. A second iron core is disposed at the inner side of the respective vertical plate portion. A brazing filler metal rising gap is disposed between the second iron cores.

FIG. 9 shows the general structure of a conventional wave soldering device, wherein a work conveyor 14 adapted to convey workpieces to be soldered, such as component-mounted substrates or the like, extends from a workpiece inlet 12 to a workpiece outlet 13 of a device cover 11.
A fluxer 15 for applying foamed flux to workpieces, a preheater 16 for preheating the workpieces, a solder bath 17 for soldering the workpieces by using molten solder ejected from wave nozzles, and a fan 18 for cooling the workpieces after soldering are arranged in this order along the conveyor 14.
A primary wave nozzle 21a and a secondary wave nozzle 21b are disposed in the solder bath 17. A wave-forming plate 22 has numerous ejection holes is provided at the open top of the-primary wave nozzle 21a. The primary wave nozzle 21a is adapted to feed molten solder over the entire workpiece, covering every corner of the electrode portions and other parts of chip components by means of numerous small primary waves W1 which are ejected as irregular spouts from the ejection holes of the wave-forming plate 22. The secondary wave nozzle 21b is adapted to adjust the shapes of soldered parts by means of gentle secondary waves W2.
As shown in FIG. 10, the solder bath 17 is provided with a pressure duct 23 fitted in an opening at the bottom of the nozzle body 21 of the wave nozzles 21a, 21b, and a pump impeller 24 disposed at the end of the pressure duct 23. The solder bath 17 also includes a suction opening 25 and a motor drive mechanism 26 associated with the pump impeller 24.
Molten solder introduced from the suction opening 25 as a result of rotation of the pump impeller 24 is fed under pressure through the pressure duct 23 into the nozzle body 21 and emitted from the nozzle body 21 in waves so that the undersides of workpieces P, which may be component-mounted substrates, are soldered while they are conveyed, being held between conveyor claws 27 of the conveyor 14. The major part of the solder waves directly returns onto the molten solder surface 28 in the solder bath 17 and is circulated into the suction opening 25 of the pump impeller 24.
Various brazing apparatuses using an electromagnetic pump are disclosed in, for example, Japanese Patent Publication Nos. 42590-1976, 31628-1990 and 60581-1991, and Japanese Utility Model Publication No. 17572-1988. Electromagnetic pumps used in those brazing apparatuses are either a direct current type or an alternating current type.
A direct-current type electromagnetic pump is adapted to generate a thrusting force to a conductive brazing filler metal, such as tin, over its path of motion by applying a magnetic field perpendicularly to the path of the conductive brazing filler metal and feeding direct electric current perpendicularly to both the path of motion and the magnetic field.
An alternating-current type electromagnetic pump is an electromagnetic induction pump which includes induction coils arranged on a plane along a path traveled by a conductive brazing filler metal and is adapted to generate a thrusting force to the brazing filler metal by feeding AC current having lagged phases to the induction coils, thereby generating a shifting magnetic field in the path traveled by the conductive brazing filler metal to permit the electromagnetic induction to generate electromotive force on the conductive brazing filler metal in its path of motion so that electric current generated by the electromotive force of the brazing filler metal flows in the magnetic flux in the magnetic field.
With a wave soldering device of a type which calls for force-feeding molten solder by means of a pump impeller rotated by a conventional motor drive mechanism, it is difficult to reduce the amount of solder, because of structural limitations in how small the solder bath can be.
To be more precise, as the solder bath has to be sufficiently deep in order to prevent oxidized solder from being entangled in the portion where the impeller is turning, the volume of the entire solder bath becomes large.
On the other hand, although a conventional brazing apparatus which calls for force-feeding brazing filler metal by using an electromagnetic pump and ejecting it in the form of waves requires less brazing filler metal compared with the wave soldering device described above, it occupies a considerable space along the conveyance path of workpieces.
For this reason, unlike a motor-driven wave soldering device, no conventional electromagnetic pump type brazing apparatus has ever employed the art that calls for serially arranging two brazing apparatus and performing two kinds of brazing by means of primary waves and secondary waves.
Simply arranging two conventional electromagnetic pump type brazing apparatuses to be used respectively for primary brazing and secondary brazing would not only double the surface area of the device, which would take up too much space, but would also require twice as much brazing filler metal.
Due to environmental protection regulations, the demands for brazing filler metal which does not contain lead (what is generally called lead-free solder) are recently on the increase. Because lead-free solders are made of materials such as indium or the like, which are 3 to 10 times as expensive as ordinary solder made of tin and lead, it is necessary to reduce the quantity of the brazing filler metal to be used as much as possible.
In order to solve the above problems, an object of the present invention is to provide an electromagnetic pump type brazing apparatus which is capable of forming waves at a plurality of locations without taking up much space. Another object of the present invention is to provide an electromagnetic pump type brazing apparatus which is capable of reducing the quantity of brazing filler metal.

Brazing apparatus having electromagnetic induction pumps for moving a brazing filler metal in contact with a workpiece


An IP usage pattern of a first computer system is monitored by a second computer system that is remotely located from the first computer system. The second computer system is associated with an ISP. First parasite software may be identified based on an abnormal change in the IP usage pattern. The abnormal change in the IP usage pattern may be detected by comparing the IP usage pattern to a baseline model of IP usage for the first computer system. Anti-parasite software associated with the first parasite software may be forwarded from the ISP to the first computer system.

Parasite software is software that has been installed on a user's computer, typically without the user's knowledge, to perform tasks on behalf of another individual or entity. Examples of parasite software include spyware and adware. Often, the objective of the parasite software is not to harm the user's computer, but rather to provide information to the parasite software's owner and/or to consume free computer resources.
Unlike viruses and worms that palpably and malevolently affect a computer, parasite software often goes unnoticed on users' personal computers. Many anti-virus software packages installed on users' personal computers do not detect the presence of parasite software. Thus, a user may take corrective action to remove parasite software only when he/she either notices performance issues with his/her personal computer or learns that the parasite software exists on another user's computer.

Method and system for remotely detecting parasite software


A vehicle drive system can include wheels that have flat portions corresponding to the areas of relative flexibility of stiffness of a track. When the discontinuous, angular profile of the track of the vehicle can deform about a matching angularly-profiled wheel, a smoother ride with less power loss can be produced, and ratcheting (caused by loosened or mismatched engagement between the track and a driving structure) can be reduced.

Driven tracks are often used in vehicles in which wheels would be inappropriate. For example, tractors or snowmobiles, which are operated on terrain which is unsuitable for wheels, conventionally use driven tracks to move across mud, snow, sand, or other surfaces.
Driven tracks are conventionally made of a flexible material such as rubber, with features that are configured to engage with a drive wheel. For example, a conventional snowmobile track includes a series of inner engagement features (such as drive lugs) that engage with the teeth of a geared drive wheel or sprocket. On the opposite, outer side of the track, there can be a set of lugs, fins, or other features that can dig or scoop into the snow. In operation, the teeth of the drive wheel engage with the inner engagement features to move the track, the radially outer circumference of which propels the snowmobile relative to underlying snow, with additional traction provided by the fins or other outer-edge lug features.
In addition to the drive wheel, most snowmobiles also include idler wheels. These idler wheels can engage with the track and/or with the inner features of the track. In some conventional systems, the spacing between the idler wheel and the drive wheel can be modified, such that the position of the idler wheel can be moved to set a desired level of tension in the track.
Setting the tension level too low can result in "ratcheting," a condition in which the inner engagement features don't full engage with the drive wheel. The drive wheel then spins without providing a corresponding movement in the track. As the teeth or other geared features of the drive wheel spin relative to the track, the periodic impact of the teeth on the inner engagement features causes a sound and feeling of ratcheting.
Ratcheting can be avoided by properly tensioning the track. With sufficient tension on the track holding it in contact with the drive wheel, ratcheting cannot occur. Over time, however, deformation or loosening of the track, or even movement of the idler wheel, can cause looser engagement between the drive wheel and the track. Even a well-tensioned track, therefore, can eventually begin ratcheting if not properly maintained and re-tensioned.
Ratcheting becomes all the more likely with higher-powered snowmobiles. As the level of torque provided to the drive wheel increases, the necessary tension to prevent ratcheting also increases. Tensioning the belt sufficiently to prevent ratcheting in high-powered snowmobiles causes stretching and loosening of the track even faster than in their lower-powered, lower-tension systems. Generally, the trend in snowmobile technology in the past several decades has been to increase power, requiring higher levels of tension to prevent ratcheting.
As described above, ideally to prevent ratcheting the track would be tightened to maintain engagement between the belt and the drive wheel. Arbitrarily increasing the tension on the track brings with it other problems, however.
The main disincentive to increasing the track's tension is that increased tension causes a draw on the power from the drive wheel. A very high tension track can require several horsepower just to run at low speed, as power is dissipated in deforming the band around the contours of the drive wheel, the idler wheel, and any other guides or structures in the path of the track. Therefore, the level of tension has conventionally needed to be maintained between a minimum (below which ratcheting occurs) and a maximum (above which power is unnecessarily dissipated), all while the track itself is loosening, requiring constant minor adjustment to balance these two phenomena.
It should be understood that, while the problems with existing track systems are described above with respect to snowmobiles, these same problems could also occur in other track-driven systems. For example, tractors, drive belts, or pulleys also can exhibit ratcheting, belt stretching, and power loss at high tension.

Track wheel with decreased power dissipation


A bathroom accessory mountable to a generally vertical flat surface such as glass, mirror, tile, fiberglass or metal. The bathroom accessory makes efficient use of space available in a bathroom.

A typical household bathroom is a small and confined place. Accordingly, there is a limited amount of available storage space for items needed while in the bathroom. As a result, most household bathrooms quickly become disorganized and cluttered, making it difficult, time-consuming and inconvenient to locate items that are needed while in the bathroom. Moreover, the bathroom becomes increasingly difficult to maintain and clean.
The present invention overcomes these and other drawbacks and provides accessories which can be conveniently stored in a bathroom and which allow for efficient use of existing bathroom space.


A method includes positioning a first active region adjacent to a pair of second active regions in an initial integrated circuit (IC) layout diagram of an initial cell, to align side edges of the first active region and corresponding side edges of each second active region of the pair of second active regions along a cell height direction. The method further includes arranging at least one first fin feature in the first active region, to obtain a modified cell having a modified IC layout diagram. The side edges of the first active region and the corresponding side edges of each second active region extend along the cell height direction. A height dimension of the first active region in the cell height direction is less than half of a height dimension of each second active region of the pair of second active regions in the cell height direction. At least one of the positioning the first active region or the arranging the at least one first fin feature is executed by a processor.

An integrated circuit (IC) typically includes a number of semiconductor devices represented in an IC layout diagram. An IC layout diagram is hierarchical and includes modules which carry out higher-level functions in accordance with the semiconductor device's design specifications. The modules are often built from a combination of cells, each of which represents one or more semiconductor structures configured to perform a specific function.
Cells are configured to provide common, low-level functions, often performed by transistors based on gate regions that intersect active regions, such as source/drain diffusion regions. The elements of a cell are arranged within a cell boundary and electrically connected to other cells through interconnect structures.
Cells having pre-designed layout diagrams, sometimes known as standard cells, are stored in standard cell libraries and accessible by various tools, such as electronic design automation (EDA) tools, to generate, optimize and verify designs for ICs.

Integrated circuit layout method, device, and system

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.


An apparatus for determining aberrations of an eye includes a patient head rest allowing for positioning adjustment. The patient head rest is operable with an optical table having a base. The base includes a probe beam generating apparatus, probe beam directing optics which itself comprises a beam splitter; a mirror; and a lens. The probe beam directing optics is capable of directing a probe beam toward an eye of a patient positioned on the patient head rest. Video image components are provided and comprise a light source, a mirror; and a video camera. The video image components are capable of generating an image of an eye of a patient positioned on the patient head rest. Eye fixation components generate a target that the eye of a patient positioned on the patient head rest can view. The eye fixation components comprise a fixation target, a light source, a lens, and a mirror. Wavefront directing and analyzing components measure a wavefront emanating from the eye of a patient positioned on the patient head rest and determine aberrations of the eye that range from at least about + or xe2x88x921 diopters to at least about + or xe2x88x926 diopters. The wavefront directing and analyzing components include a lens; a mirror, a microlens array, a camera, and a data processor.

The invention relates generally to optical aberration measurement and analysis, and more particularly to an objective measurement of optical systems, such as systems of a human eye.
Optical systems having a real image focus can receive collimated light and focus it at a point. Such optical systems can be found in nature, e.g., human and animal eyes, or can be man-made, e.g., laboratory systems, guidance systems, and the like. In either case, aberrations in the optical system can affect the system""s performance. By way of example, the human eye will be used to explain this problem.
A perfect or ideal eye diffusely reflects an impinging light beam from its retina through optics of the eye which includes a lens and a cornea. For such an ideal eye in a relaxed state, i.e., not accommodating to provide near-field focus, reflected light exits the eye as a sequence of plane waves. However, an eye typically has aberrations that cause deformation or distortion of reflected light waves exiting the eye. An aberrated eye diffusely reflects an impinging light beam from its retina through its lens and cornea as a sequence of distorted wavefronts.
There are a number of technologies that attempt to provide the patient with improved visual acuity. Typically, treatment is determined by placing spherical and/or cylindrical lenses of known refractive power at the spectacle plane (approximately 1.0-1.5 centimeters anterior to cornea) and literally asking the patient which lens or lens combination provides the clearest vision. This is an imprecise measurement of true distortions in the reflected wavefront because 1) a single spherocylindrical compensation is applied across the entire wavefront, 2) vision is tested at discrete intervals (i.e., diopter units) of refractive values, and 3) subjective determination by the patient is employed. Thus, conventional methodology for determining refractive errors in the eye is substantially less accurate than the techniques now available for measuring the ocular aberrations.
One method of measuring ocular refractive errors is disclosed in U.S. Pat. No. 5,258,791 to Penney et al. for xe2x80x9cSpatially Resolved Objective Autorefractometer,xe2x80x9d which teaches the use of an autorefractometer to measure the refraction of the eye at numerous discrete locations across the corneal surface. The autorefractometer is designed to deliver a narrow beam of optical radiation to the surface of the eye, and to determine where that beam strikes the retina using a retinal imaging system. Both the angle of the beam""s propagation direction with respect to the optical axis of the system and the approximate location at which the beam strikes the corneal surface of the eye are independently adjustable. However, a small uncertainty or error in the location of the beam""s point of incidence on the cornea exists due to the curved corneal surface. For each point of incidence across the corneal surface, the refraction of the eye corresponding to that surface point can be determined by adjusting the angle at which the beam strikes the cornea until the beam refracted on to the iris strikes the fovea centralis. Adjustment of the beam angle of propagation can be accomplished either manually by the patient or automatically by the autorefractometer, if a feedback loop involving a retinal imaging component is incorporated.
Penney ""791 further teaches the use of the autorefractometer measurements in determining the appropriate corneal surface reshaping to provide emmetropia, a condition of a normal eye when parallel beams or rays of light are focused exactly on the retina and vision is perfect. This is accomplished by first obtaining an accurate measurement of corneal surface topography using a separate commercially available device. A mathematical analysis is then performed using an initial corneal topography at each surface reference point, the measured refraction at each surface point, and Snell""s law of refraction, to determine a desired change in surface contour at each reference point.
A major limitation to the approach described by Penney ""791 is that a separate measurement of corneal topography is desired to perform the Snell""s Law analysis of needed refraction change. This adds significantly to the time and cost of a complete and desirable diagnostic evaluation. Further, the accuracy of the refraction change analysis will be dependent upon the accuracy of the topographic measurement and the accuracy of the autorefractometer measurement. In addition, any error in the spatial orientation of a topography map with respect to a refraction map will degrade the accuracy of the measured profile. Yet another limitation to known approaches such as described in Penney ""791, by way of example, is that test points on the corneal surface are examined sequentially. Eye motion during the examination, either voluntary or involuntary, could introduce substantial errors in the refraction measurement. Penney ""791 teaches detection of such eye movement by deliberately including measurement points outside the pupil, i.e., in the corneal region overlying the iris, where the return from the retina will obviously be zero at specific intervals in the examination sequence. However, this approach may still allow substantial undetected eye movement error between such iris reference points.
By way of example, one method and system known in the art, are disclosed by Junzhong Liang et al. in xe2x80x9cObjective Measurement Of Wave Aberrations Of The Human Eye With The Use Of A Hartmann-Shack Wave-Front Sensor,xe2x80x9d published in the Journal of the Optical Society of America, Volume 11, No. 7, July 1994, pages 1949-1957. Liang et al. teach the use of a Hartmann-Shack wavefront sensor to measure ocular aberrations by measuring the wavefront emerging from the eye by the retinal reflection of a focused laser light spot on the retina""s fovea. The actual wavefront is reconstructed using wavefront-estimation with Zernike polynomials.
The imprecise measurement technique of placing lenses of known refractive power anterior to the cornea and asking a patient which lens or lens combination provides the clearest vision has been improved with the use of autorefractometers, as described in Penny ""79, or with the use of wavefront sensors as described by Liang et al. Spatially resolved refraction data, in combination with measured existing surface contour of the anterior surface of the eye, enable a calculation of a detailed spatially resolved new contour. However, it would be an improvement in this art if such vision measurements could be made without the need for this contour data, and further without the need for feedback from the patient regarding an appropriate lens. Liang et al. discloses the use of a Hartmann-Shack wavefront sensor to measure ocular aberrations by measuring the wavefront emerging from the eye by retinal reflection of a focused laser light spot on the retina""s fovea. A parallel beam of laser light passes through beam splitters and a lens pair which brings the beam to a focus point on the retina by the optics of the eye. Possible myopia or hyperopia of the tested eye is determined by movement of a lens within the lens pair. The focused light on the fovea is then assumed to be diffusely reflected and acts as a point source located on the retina. The reflected light passes through the eye and forms a distorted wavefront in front of the eye that results from the ocular aberrations. The aberrated wavefront is then directed to the wavefront sensor.
A point source of radiation on the retina would be ideal for such measurements. However, when the perfect eye receives a collimated beam of light, the best possible image on the retina is a diffraction limited spot. As illustrated by way of example, with Penny et al. and Liang et al., discussed above, and typical for those of skill in the art, parallel or collimated beams are used with the optics of the eye being measured to achieve this diffraction limited spot for such objective measurements. To do so, a setup for each patient includes a lens or lens combination and adjustments thereto for accommodating that patient""s specific visual acuity. Providing a lens combination, as well as setting up for their use becomes cumbersome, time consuming, and at an additional expense. Eliminating the need for such optics is desirable and eliminates a variable within optical measurement systems that typically include many variables. Further, there is a need for providing optical characteristics of an eye without requiring feedback from the patient. By way of example, the patient may be a wild or domestic animal, living or dead.
The Hartmann-Shack wavefront sensor disclosed by Liang et al. includes two identical layers of cylindrical lenses with the layers arranged so that lenses in each layer are perpendicular to one another, as further disclosed in U.S. Pat. No. 5,062,702 to Bille. In this way, the two layers operate as a two-dimensional array of spherical lenslets that divide the incoming light wave into sub-apertures. The light through each sub-aperture is brought to focus in the focal plane of the lens array where a charge coupled device (CCD) image module resides.
The system of Liang et al. is calibrated by impinging an ideal plane wave of light on the lenslet array so that a reference or calibrating pattern of focus spots is imaged on the CCD. Since the ideal wavefront is planar, each spot related to the ideal wavefront is located on the optical axis of the corresponding lenslet. When a distorted wavefront passes through the lenslet array, the image spots on the CCD are shifted with respect to a reference pattern generated by the ideal wavefront. Each shift is proportional a local slope, i.e., partial derivatives of the distorted wavefront, which partial derivatives are used to reconstruct the distorted wavefront, by means of modal wavefront estimation using Zernike polynomials.
However, the system disclosed by Liang et al. is effective only for eyes having fairly good vision. Eyes that exhibit considerable myopia (near-sightedness) would cause the focus spots to overlap on the CCD, thereby making local slope determination practically impossible for eyes having this condition. Similarly, eyes that exhibit considerable hyperopia (farsightedness) deflect the focus spots such that they do not impinge on the CCD thereby again making local slope determination practically impossible for eyes having this condition.
In general, an embodiment of the present invention provides a method and system for objectively measuring aberrations of optical systems by wavefront analysis. Another embodiment further provides for the objective measurement of ocular aberrations having a dynamic range that can cope with large amounts of such aberrations so as to be useful in practical applications. Still another embodiment of the present invention provides a method and system for objectively measuring ocular aberrations using a wavefront analyzer of simple and inexpensive design.
One embodiment of the present invention provides an apparatus and method for making objective and detailed measurements of aberrations present in human eyes. Aberrations measured by the apparatus include xe2x80x9chigher orderxe2x80x9d phenomena, such as spherical aberration and coma, in addition to the traditional myopia/hyperopia and astigmatism.
In accordance with an embodiment of the present invention, an energy source generates a beam of radiation. Optics, disposed in the path of the beam, direct the beam through a focusing optical system that has a rear portion which provides a diffuse reflector. The beam is diffusely reflected back from the rear portion as a wavefront of radiation that passes through the focusing optical system to impinge on the optics. The optics project the wavefront to a wavefront analyzer in direct correspondence with the wavefront as it emerges from the focusing optical system. A wavefront analyzer is disposed in the path of the wavefront projected from the optics and calculates distortions of the wavefront as an estimate of ocular aberrations of the focusing optical system. The wavefront analyzer includes a wavefront sensor coupled to a processor that analyzes the sensor data to reconstruct the wavefront to include the distortions thereof.
One embodiment of the present invention, herein described by way of example, utilizes wavefront sensing to measure the aberrations of the eye. When one considers the perfect or ideal eye as earlier described, a perfectly collimated light beam (i.e., a bundle of parallel light rays) incident on the perfect, ideal emmetropic eye, focuses to a diffraction-limited small spot on the retina. This perfect focusing is true for all light rays passing through the entrance pupil, regardless of position. From the wavefront perspective, the collimated light represents a series of perfect plane waves striking the eye. Due to the reversible nature of light ray propagation, the light emanates from an illuminated spot created on the retina as wavefronts exiting the ideal eye as a series of perfect plane waves. The apparatus of the present invention achieves this ray reversal effect using a probe beam optical path for projecting a small diameter, eye-safe laser beam into the eye and onto the fovea. The light scattered from the irradiated retina serves as a secondary source for a re-emitted wavefront. The probe laser beam strikes the retina at an appropriate foveal location to illuminate a sufficiently small spot. A fixation optical path is provided which includes a reference target aligned to an optical axis. This allows a patient to fixate on a target. A video path provides a video image of the eye plane, centered on the optical axis. A video image of the eye allows a clinical operator to assist in orienting the eye for the wavefront measurement.
Embodiments of the present invention, herein described, provide a refraction measurement system that easily accommodates the measurement of vision characteristics of the eye, even in the presence of finite refractive errors. The time for a patient to be in a fixed position during examination is reduced, while at the same time providing a useful source of light on the retina of the eye to be measured regardless of the characteristics of the eye of that patient or other patients to be examined. Desirably, measurements are made without requiring patient or operator feedback. One method aspect of the invention for measuring optical characteristics of an optical system, such as the eye, includes focusing an optical beam onto an anterior surface of the eye for providing a finite source of secondary radiation on the retina of the eye, which secondary radiation is emitted from the retina as a reflected wavefront of radiation that passes through the eye. The reflected wavefront is directed onto a wavefront analyzer for measuring distortions associated with the reflected wavefront.
In one embodiment, the radiation is optical radiation and the wavefront sensor is implemented using a plate and a planar array of light-sensitive cells. The plate is generally opaque but that has an array of light transmissive apertures that selectively let impinging light therethrough. The plate is disposed in the path of the wavefront so that portions of the wavefront pass through the light transmissive apertures. The planar array of cells is arranged parallel to and spaced apart from the plate by a selected distance. Each portion of the wavefront passing through one of the light transmissive apertures illuminates a geometric shape covering a unique plurality of cells.
As herein described, by way of example, the wavefront optical path of the present invention relays the re-emitted wavefront from the corneal plane to an entrance face of a Hartman-Shack wavefront sensor. The wavefront incident on the sensor is received by a sensitive charged-coupled device (CCD) camera and an optical plate containing an array of lenslets. The lenslet array is parallel to the CCD detector face with a distance therebetween approximately equal to the focal length of each lens in the lenslet array. The lenslet array divides the incoming wavefront into a matching array of xe2x80x9cwavelets,xe2x80x9d each of which focuses to a small spot on the CCD detector plane. The constellation of wavelet spots in the CCD is used to reconstruct the shape of the incident wavefront. Collimated light striking the lenslet at normal (perpendicular) incidence would focus to the spot on the CCD face where this optical axis intersects. The optics of the apparatus provides such collimated light to the wavefront sensor using a calibration optical path. Collimated light CCD images are routinely obtained as part of a daily calibration process and used for reference in analyzing experimental data.
However, in the case of a reflected aberrated wave front, light focuses to a spot displaced from the collimated reference point by a distance Dx. The distance from the lenslet face to the CCD surface, Dz, is precisely known. Therefore, dividing the measured displacement, Dx, by the known propagation distance, Dz, the slope of the wavefront at the location of this lens element is determined. The same calculation is applied in the y direction within the plane, and the entire process applied to every lenslet element irradiated by the wavefront. A mathematical algorithm is then applied to reconstruct the wavefront shape consistent with the calculated Dx/Dz and Dy/Dz slope data. Regardless of which wavefront sensor is used, the distance between the planar array of cells and the opaque plate, or the array of lenslets, can be varied to adjust the slope measurement gain of the wavefront sensor and thereby improve the dynamic range of the system.
Another measure of dynamic range enhancement is provided by the focusing optics. The focusing optics includes first and second lenses maintained in fixed positions in the path of the beam and wavefront. An arrangement of optical elements is disposed between the lenses in the path of the beam and the wavefront. The optical elements are adjustable to change the optical path length between the lenses.
A method aspect of the present invention, as herein described, determines aberrations of an eye requiring greater than a + or xe2x88x923 diopter change, and includes directing an optical beam onto a retina of an eye, reflecting the optical beam from the retina of the eye, determining characteristics of a wavefront in a reflected optical beam, and generating data based on the characteristics of the wavefront, which data quantifies the aberrations of the eye. The data may further be generated based on refractive indices of media through which the optical beam passes. Yet further, data based on the characteristics of the wavefront, which data quantifies the aberrations of the eye for a discrete section of the eye may also be generated.
One method for determining aberrations of an eye, herein described by way of example, includes directing a probe beam along a probe beam path toward an eye, directing a fixation image along a fixation image path toward the eye, directing a light source along a video image path toward the eye, generating a video image of the eye, directing a wavefront originating from the eye along a wavefront path, wherein the probe beam path, the fixation image path, the video image path, and the wavefront path are coincident at least along a portion of their respective paths, the probe beam path terminating at the retina of the eye and the probe beam reflecting from the retina of the eye as a wavefront, aligning the eye with the probe beam path based at least in part on the video image of the eye generated by the light source directed along the video image path, measuring the wavefront, and generating data representative of the aberrations of the eye based on the measurement of the wavefront. Further, the aligning of the eye with the probe beam path based at least in part on the video image of the eye generated by the light source directed along the video image path, may have the wavefront pass through a single microlens array.
One apparatus for determining the aberrations of an eye comprises a patient head rest comprising vertical adjustment, the patient head rest associated with an optical table having a base. The base carries a probe beam generating apparatus, probe beam directing optics, the probe beam directing optics comprising a beam splitter; a mirror; and a lens, the probe beam directing optics being capable of directing a probe beam toward an eye of a patient positioned on the patient head rest, video image components, the video image components comprising a light source, a mirror, and a video camera, the video image components being capable of generating an image of an eye of a patient positioned on the patient head rest, eye fixation components, the eye fixation component comprising a fixation target; a light source; a lens; and a mirror, the fixation components being capable of generating a target that the eye of a patient positioned on the patient head rest can view, and wavefront directing and analyzing components, the wavefront directing and analyzing components comprising a lens, a mirror, a microlens array, a camera, and a data processor. The wavefront directing and analyzing components are capable of measuring the wavefront emanating from the eye of a patient positioned on the patient head rest and determining aberrations of said eye that range from at least about + or xe2x88x921 diopters to at least about + or xe2x88x926 diopters.

Apparatus and method for objective measurement of optical systems using wavefront analysis


A shoe with an improved cushioning insole containing perfluoropolyether. The perfluoropolyether resists breakdown, extending the useful life of both the insole and the shoe. Preferably, the insole contains both low- and high-viscosity perfluoropolyethers as well as a gas to enhance shock-absorbing capabilities.

Insoles have long been used to cushion the impact of a person's foot with a supporting surface. The basic concept of shock absorption by, for example, use of a fluid-containing insole that transfers the fluid from the heel to the ball or forward portion of the user's foot has been known for many years. Furthermore, gas-filled sacs have also been used as orthopedic cushions to replace the inner sole of shoes. To this end, gas cushions have been designed to accomplish a number of varied purposes, including to provide an orthopedically shaped surface generally conforming to the curvature of the human foot, to provide means for softening the jar incident to the operation of walking, to provide means concealed within the shoe for increasing the apparent height of a human being, to correct a manner of walking of the wearer, and to form a comfortable and natural support for the arch of the foot.
Inflated cushioning and impact-absorbing insole devices adapted for placement within articles of footwear are also known. Such devices generally have an upper layer and lower layer formed of a flexible, fluid-impermeable material, and may be filled with a fluid or gel. The upper and lower layers are sealed together, thereby forming a plurality of sealed, laterally-spaced tubular members. The volume of fluid or gel disposed within the tubular chambers may entirely or partially fill all of the chambers. Existing liquid or gels used for this purpose include those disclosed in U.S. Pat. No. 4,756,311; such as a mixture of carbopol.TM., propyleneglycol, formaldehyde, sodium hydroxide, color dye and water. Another fluid or gel disclosed for this purpose is that of U.S. Pat. No. 3,885,403, which comprises water, glycol and carbopol 940.
However, a significant disadvantage associated with existing fluid or gel-filled insoles is that the fluid or gel breaks down as a result of repeated use, thus significantly reducing the cushioning ability of the insole. Accordingly, there is a need in the art for a material which, when used as a component for cushioning insoles, resists breakdown over the course of normal use. The present invention fulfills this need, and provides further related advantages.


Systems and methods are provided for computer tomography (CT) imaging. An attenuation transform component configured to map voxels in a received set of cross-sectional CT images to associated brightness values according to a piecewise transform function to produce a set of transformed images. A user interface is configured to provide the set of transformed images to a user at an associated display.

Computed tomography is a medical imaging procedure that utilizes computer-processed X-rays to produce tomographic images or 'slices' of specific areas of the body. These cross-sectional images are used for diagnostic and therapeutic purposes in various medical disciplines. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. Computed tomography produces a volume of data that can be manipulated in order to demonstrate various bodily structures based on their ability to block the X-ray beam. Although most common in medicine, computed tomography is also used in other fields, such as nondestructive materials testing.

Augmented reconstruction for computed tomography


A method and apparatus for constructing a three-dimensional object. There is provided a lamination unit for holding and pressing a block of material; a slicing unit for cutting the block to form a horizontal layer having a first working surface and a cut block having a second working surface; a profiling means for profiling at least one of the working surfaces into at least one planar element; and an electronic means for receiving XYZ information corresponding to the shape of the object, for processing the XYZ information into a plurality of computerized cross-sectional representations of the shape, and for controlling the operation of the lamination means, the slicing means, and the profiling means. Formation occurs by providing the electronic means with the XYZ information, placing the block in a position for holding by the lamination means; slicing the block to provide the horizontal layer having the first working surface and the cut block having the second working surface; profiling at least one of the working surfaces to form the planar element having a shape corresponding to the computerized cross-section representation at that slicing level; pressing the second working surface of the cut block against the first working surface of the horizontial layer using the lamination means; and repeating the slicing and profiling steps until the object is formed.

During the early 1980's improvements in computer technology greatly facilitated the description, manipulation, and representation of complex three-dimensional information in digital form. This progress was particularly dramatic in the area of computer aided design (CAD). Methods of physical fabrication, however, were almost exclusively limited to old subtractive methods which were adapted for computer numerical control (CNC). Consequently, a number of people noted the great disparity between the ability to describe and represent complex three-dimensional information in digital, nonphysical, form and the ability to turn those descriptions into correspondingly detailed physical forms. This disparity between nonphysical and physical capabilities led an increased number of researchers to focus on a variety of new techniques which promised to provide fast and economical three-dimensional "hard copy," with little or no constraint on complexity.
Stereolithography, the first commercially successful method of "freeform fabrication," was first publicly demonstrated in late 1987. Since then a wide variety of new methods have appeared. Most of these new methods are performed in a layer-by-layer fashion and are characterized by their additive nature, either solidifying or depositing small portions of material onto an object being produced. One of these new additive methods is commonly called laminated object manufacturing (LOM). Unlike the others, however, LOM is distinguished by the fact that it employs both additive methods (lamination of a layer) and subtractive methods (cutting of a cross-sectional shape) in order to manufacture objects.
Part of the history of freeform fabrication and LOM is outlined in U.S. Pat. No. 5,354,414 to Feygin. This patent also suggests various methods of forming objects from layers of powder and from layers of sheet material. Of particular relevance to the current application are methods of "cut-on-the-stack" lamination which were added as new material on Oct. 4, 1989. These methods eliminate most registration problems by laminating a layer of material before cutting that layer of material to shape. In some embodiments described, it was also suggested that the surrounding material be left in place, in order to help support subsequent laminations. In each sheet-larnination embodiment the thickness of the sheet material is determined and formed prior to lamination.
The lamination work which I began in early 1986 was not described in the background to U.S. Pat. No. 5,354,414. This work focused exclusively on the lamination of sheet material and led to U.S. Pat. No. 5,015,312. It also led to the paper "Three-Dimensional Printing," dated Apr. 27, 1988 and subsequent editions, which were widely and nonconfidentially distributed to people who were involved in this field. The lamination papers which I published all describe the "cut-on-the-stack" method and the advantages of cutting parting lines and leaving the surrounding material in place to form a supporting shell. In each embodiment, the thickness of the sheet material is determined and formed prior to lamination.
Since the commercial introduction of Stereolithography in 1987, the number of freeform fabrication research efforts has increased dramatically. Without attempting to cover all of the many variations, two methods should be noted here. They are "Shapemaker II," developed and marketed by Schroff Development Corporation of Mission, Kans., and "Computer-Aided Manufacturing of Laminated Engineering Materials" developed by CAM-LEM, Inc., of Cleveland, Ohio. Neither of these methods uses the cut-on-the-stack method. In each case, a cutting station is configured to prepare a single layer of material for lamination at a separate lamination station. In some embodiments, methods of five-axis cutting are used in order to vary the edge profile of individual layers for the purpose of reducing the "stair-stepping" error which is characteristic of methods which fabricate complex shapes by assembling or otherwise layering cross-sectional shapes which have square edge profiles.
The CAM-LEM, Inc. methods referenced above also include the construction of shapes from more than one material. At a special cutting station, these methods create component cross-sections from a selection of sheet materials, differing in both thickness and in composition. These cross-sections are then assembled into the product shape. In some cases, portions of individual layers are cut from sheets of specially formulated "fugitive materials." These materials are designed to provide structural support during critical phases of the fabrication process but to be reduced to a removable powder ash by heating the laminated object in an oven.
Additional methods of lamination from preformed sheet materials are included in currently pending U.S. patent application Ser. No. 08/587,103. These are hereby fully incorporated by reference herein as though set forth in full.
There are a number of drawbacks to each of the lamination methods and apparatus which have been disclosed to date. First, the drawbacks which apply to all of the methods, include:
A. Additive fabrication methods create objects by adding material in discrete increments. This creates the dilemma of either accepting undesirable discontinuities, or "stairsteps," in the surface or of reducing the increment size to a point which makes fabrication time and cost excessive for many purposes. Since laminated object manufacturing is a hybrid which also uses subtractive methods, it has the potential to entirely eliminate stairsteps and other unwanted discontinuities in shape. However, the subtractive mode is not yet fully exploited. The vertical-edge cutting of the current LOM hybrids cannot yet produce shapes which are equal in accuracy and smoothness to the shapes produced by conventional, purely subtractive, milling machines.
B. Since both the geometry and the use of laminated objects vary widely, it is advantageous to be able to vary the sheet thickness, both within one laminated object and between successive laminated objects. Since laminated objects are currently fabricated from sheetstock which is created by an entirely separate process, however, it is impractical to provide preformed sheet materials in every thickness which may be determined to be optimal for a particular layer. The conventional LOM approach to using preformed sheet materials is to supply sheet material which is thin enough for the most complicated portions of a particular project and to accept the inefficiencies of using a thinner-than-optimal material in less demanding portions of the project. When relatively simple objects are fabricated from thinner-than-optimal layers, the time penalty of unnecessary lamination is cumulative over many layers. In "cut-on-the-stack" apparatus material thickness changes are only made when absolutely required, with manual intervention. In the more complex "cut-off-the-stack" apparatus, changes in thickness may be somewhat easier, but are severely limited by the supply stock which is available.
C. One way to achieve optimum layer thickness is to use a variation on "layer-planing" operations which are fundamental to related methods of freeform fabrication, such as those employed by Sanders Prototype, Inc. of Wilton, N.H., and Cubital, Ltd. of Raanana, Israel. The LOM variation on this method would laminate a thicker sheet than required and then create a new "working plane" on a layer of optimum thickness by removing the excess portion of material. This alternative increases the percentage of raw material which must be discarded as waste.
D. When laminated layers are thin, they have little structural strength or resistance to deflection perpendicular to the slicing plane. This weakness makes support of cantilevers and bonding of layers particularly critical. This increases the need for excess material to be left in-place for structural support and increases the need for selective bonding, to facilitate detachment of the excess material. The need for support also creates special problems at internal voids.
E. The lamination of certain materials offers special functional potential beyond visualization and prototyping. Unlike the papers and plastics most commonly used in current lamination machines, the cutting and bonding characteristics of materials such as metals and green-state ceramic and metal powders may make it especially helpful to be able to adjust the relative usage of additive versus subtractive modes of fabrication. Especially when precision and smoothness are important, it may be advantageous to minimize the "additive mode" by reducing the number of laminations to a minimum, while simultaneously maximizing the "subtractive mode" by increasing the amount and sophistication of cutting done at each level.
F. With conventional LOM machinery, all automated cutting must be done layer-by-layer. Due to the difficulty of positioning and holding the product on a suitable automated subtractive cutting machine, any final shaping operations must be accomplished by hand. Such manual operations are expensive, time consuming and vulnerable to error.
G. All fabrication processes are subject to unanticipated errors. Prior-art lamination machines lack the capability to remove and replace an unacceptable layer or layers; they generally require that errors be corrected by disposal of an entire product and repetition of each and every layer.
H. When laminated objects are built from preformed sheet materials, there are special difficulties involved in uniformly pressing and bonding sheets which are nonplanar.
Second, there are drawbacks which are specific to methods which cut cross-sectional shapes at a special cutting station and then assemble composite shapes at a lamination station, including:
I. When cutting and lamination are accomplished at separate stations, as in the CAM-LEM methods, there is a separation of crucial operations. These methods require the separate "gripping" of each newly cut sheet and then the transfer, placement and lamination of that individual sheet. The many grip-and-place operations, at least one for each layer, increases the opportunity for error. For certain purposes, however, the CAM-LEM methods offer important new options, including the fabrication of individual object layers from more than one material.
J. When cutting and lamination are accomplished at separate stations, there are special problems associated with cutting severely sloped edges. These are largely due to the lack of structural strength and support of the extreme edges, where material thickness approaches zero. In the case of laser-based machines, there is sometimes the additional problem of the condensation of vaporized material on a surface which must still be bonded. Additional difficulties may be encountered in ensuring uniform support and lamination pressure where severely sloped edges must be bonded.
K. Various algorithms have been developed in order to better approximate complex surface shapes. To date, however, it appears that no such publicly disclosed method can adequately handle changes in surface slope which do not occur along slicing planes. While this may not be significant for minor slope changes, it is a potentially serious limitation at severe slope changes, such as from a positive slope to a negative slope. If such lines of change are horizontal, the slicing plane may be adjusted to correspond, but if such lines of change are sloped, as in the thread of a screw, more sophisticated cutting capability will be required.
Third, there are drawbacks which are specific to methods which exclusively "cut-on-the-stack," including:
L. When all cutting is done on-the-stack, it is most natural to cut only one layer at one time. Although it is theoretically possible to have more than one cutting tool working on that layer, there are severe practical limitations to the obvious alternatives. Consequently, cut-on-the-stack lamination is an inherently "serial" process, like other prior-art additive fabrication methods in which one layer is fabricated at a time. Unobvious methods of parallel fabrication are one subject of my pending U.S. patent application Ser. No. 08/587,103.
M. Cutting on-the-stack has limited lamination apparatus to one accessible working plane for each lamination. This is because the opposite side of each lamination is bonded to the previous layer before any operations can be performed on it. This limitation will become more significant as lamination machinery is adapted to profile cross-sections with edge cuts which are not vertical.
For all of the above reasons, there is a clear need to improve the LOM process, particularly in the areas of quality of output, efficiency, versatility, speed and reliability of production. The present invention clearly fulfills all of these needs.

Method and apparatus for the manufacture of three-dimensional objects


An adaptive wireless communication device employable in a wireless communication network having a base station and a method of operating the same. In one embodiment, the adaptive wireless communication device includes communication circuitry configured to transmit and receive messages. The adaptive wireless communication device also includes a relay coordinator configured to provide an adaptive relay path in cooperation with the base station for a message associated with a wireless communication device as a function of a characteristic of the message.

Wireless communication networks are becoming increasingly important in the voice, video and data communications arenas as demand for "instant availability" and "position transparency" increases. Wireless types of communication networks typically employ one or more base stations that are used to communicate with a collection of wireless communication devices and associated transceivers within a cell of the wireless communication network. Historically, the wireless communication devices have been mobile telephones or paging devices. However, the types of wireless devices are steadily growing as new types of wireless products and services rapidly proliferate.
A prevalent wireless communication network employs a collection of contiguous cells wherein each cell has a base station located therein. The base station communicates directly with each wireless communication device located within its cell to accommodate its messaging. This message may be directed to another wireless communication device located within the same cell. Additionally, the message may be communicated with a wireless communication device located within another cell, or a wireless communication device that is not part of the wireless communication network. In all of these cases, the wireless communication device communicates directly with its base station to accomplish its messaging.
A characteristic such as signal strength (i.e., signal power) associated with a message between a wireless communication device and its base station may typically diminish as an inverse function of an exponential factor (e.g., the square) of the distance between them. As a practical consideration, the transmit power associated with a base station or a transmitter of the wireless communication device is limited by legal or system considerations to a maximum allowable level. Additionally, the signal path between the base station and the wireless communication device is typically not line-of-sight and may be obscured by changes in elevation or other obstacles such as tall buildings. Multiple signal paths, often producing reflections, may also introduce signal fading as these multiple signals recombine in a random manner.
Log-normal shadowing and severe weather conditions, such as storms having lightning, rain or ice, may also diminish the signal strength associated with the message. Therefore, a wireless communication device located near the periphery of a cell may experience signal strength problems that sharply degrade a quality of service associated with message whereas a wireless communication device positioned more closely within the cell to the base station does not experience such a degradation.
Accordingly, what is needed in the art is a way to reduce signal degradation associated with a wireless communication device within a wireless communication network.

Wireless communication network including an adaptive wireless communication device and a method of operating the same


The black level in raw image data captured from an image sensor does not always stay fixed at a constant level, but may change as a function of the analog gain and exposure time and may vary from one spatial location of the pixels to another. To carry out black-level correction on the raw image data, the black level of each of the color components is measured at one or more sampling locations. A look-up table is generated based on the measured black levels and a computation module is used to carry out black-level correction based on the information stored in the look-up table. The look up table may have information indicative of the analog gain level and the exposure time and the variations of black-levels in different spatial locations.

It is known in the art that the outputs of a digital camera sensor have some non-zero level even in the case when no light reaches the sensor surface. This non-zero level is caused, for example, by dark current that accumulates electrical charges into the pixels independently of the amount of light that reaches the sensor surface. The dark current usually increases with temperature. The total amount of accumulated charges also increases as a function of exposure time and the final output signal from the camera sensor may also be affected by the analog gain of the camera. This non-zero level in the sensor outputs is also known as the black level. Typically there is circuitry in the camera sensor to normalize the black level at some pre-determined fixed level. Unfortunately in many cases there remains some difference between the target level and actual level. In order to produce correct colors and intensity levels in the final image, it is necessary to determine a more accurate black level so that it can be removed from the raw data.

Method and system for black-level correction on digital image data


In one embodiment, an anti-virus verification unit detects connection messages transmitted by a network server and a network client on a network. The anti-virus verification unit determines a network address of the network client according to the connection messages. Using the network address, the anti-virus verification unit verifies if the network client has an anti-virus software.

1. Field of the Invention
The present invention relates generally to anti-virus technology, and in particular to anti-virus software implementation in a computer network.
2. Description of the Related Art
The widespread popularity of the Internet has resulted in some complications, particularly in the enterprise environment. Enterprise users, for example, typically connect to an external network or a computer by various methods through an Intranet.
Intranet users and their status cannot be strictly controlled. This loosely controlled environment provides an opportunity for computer viruses to infect the Intranet. Computer virus infection reduces productivity and causes great damage. Thus, anti-virus software installation is a standard procedure on the construction of an Intranet. That is, all computers connected to an Intranet must have anti-virus software installed to prevent computer virus infection.
An anti-virus software policy can be implemented by requiring all Intranet users to install anti-virus software. This method, however, is inefficient as many users will not install the anti-virus software in their personal computers, as some may believe the anti-virus software will be detrimental to computer performance or may have driver incompatibility.
Another method of anti-virus software implementation is to require all users to install anti-virus software when logging on to a network domain. This method may be enforceable but efficiency suffers if a verification method is not provided to detect continued use of the anti-virus software.
An enterprise can also utilize a probe application that periodically determines if all the computers already connected to the Intranet have anti-virus software installed. If any connected computer does not have anti-virus software installed, the probe application executes an installation program to install anti-virus software on the detected computers. This method provides a greater degree of enforceability but is unsuitable as large enterprises typically have numerous Intranet users. Use of the probe application is time-consuming and consumes network resources. Moreover, the execution and maintenance of the probe program may present additional problems.
Conventionally, anti-virus software implementation is regarded as an internal enterprise task. As mentioned above, more enterprises regard anti-virus software installation as a standard procedure, thus anti-virus software implementation is a developing trend. Existing techniques, however, cannot adequately accomplish anti-virus software implementation.

Method, apparatus and system of anti-virus software implementation


An RF-transparent sunshield membrane covers an antenna reflector such as a parabolic dish. The blanket includes a single dielectric sheet of polyimide film 1/2-mil thick. The surface of the film facing away from the reflector is coated with a transparent electrically conductive coating such as vapor-deposited indium-tin oxide. The surface of the film facing the reflector is reinforced by an adhesively attached polyester or glass mesh, which in turn is coated with a white paint. In a particular embodiment of the invention, polyurethane paint is used. In another embodiment of the invention, a layer of paint primer is applied to the mesh under a silicone paint, and the silicone paint is cured after application for several days at room temperature to enhance adhesion to the primer.

This invention relates to RF-transparent electrically conductive thermal membranes or blankets for protection of antennas against thermal effects from sources of radiation such as the sun.
An antenna including a parabolic reflector can, if pointed at a source of radiation such as the sun, focus the energy from the sun onto the reflector's feed structure, possibly destroying the feed. Also, the reflector may be heated in such a manner that mechanical distortion or warping occurs, which may adversely affect proper operation.
When the antenna is mounted on a satellite as illustrated in FIG. 1, a fluence of charged particles may cause electrostatic potentials across portions of the antenna made from dielectric materials. If the potentials are sufficiently large, electrostatic discharges (ESD) may occur, resulting in damage to sensitive equipments.
A sunshield adapted for use across the aperture of a reflector antenna should significantly attenuate passage of infrared, visible and ultraviolet components of sunlight to the reflector, should have a conductive outer surface to dissipate electrical charge buildup which might result in electrostatic discharge (ESD), and should be transparent to radio-frequency signals (RF), which for this purpose includes signals in the range between the UHF band (30 to 300 MHz) and Ku band (26 to 40 GHz), inclusive.
Prior art multilayer sunshields which include plural layers of aluminized polyimide film such as Kapton film cannot be used, because they are opaque to RF at the above-mentioned frequencies. An RF-transparent multilayer blanket is described in a copending application entitled "RF-TRANSPARENT SPACECRAFT THERMAL CONTROL BARRIER", filed Dec. 5, 1990 in the names of Munro, III et al. and assigned Ser. No 07/623,144. A multilayer blanket may be disadvantageous because absorbed heat can become trapped among the several layers. The temperature of the layers rises, and they produce infrared radiation which can impinge on the reflector, thereby causing the reflector to overheat.
U.S. Pat. No. 4,479,131, issued Oct. 23, 1984 to Rogers et al., describes a thermal protective shield for a reflector using a layer of germanium semiconductor on the outer surface of a sheet of Kapton, with a partially aluminized inner surface, arranged in a grid pattern which is a compromise between RF transmittance and solar transmittance. To the extent that this arrangement allows solar transmittance, the shield and/or the reflector may heat. Such heating may not be controllable because the reflectivity of the aluminized sheet may reflect infrared from the reflector back toward the reflector, and also because both the germanium and aluminization have low emissivity.
FIG. 2 illustrates a cross-section of another RF-transparent prior art sunshield, which consists of one layer of structure. The one layer of structure includes a two-mil (0.002 inch) black Kapton film 210, reinforced with adhesively-affixed Dacron polyester mesh 212 on the side facing the reflector, and with the space-facing side painted to a thickness of about four mils with a white polyurethane paint 214 such as Chemglaze Z202, manufactured by Lord Corporation of 2000 West Grandview Boulevard, Erie, Pa. 16512. The surface of the paint is vapor coated with an electrically conductive layer 216 such as 75.+-.25.ANG. of indium-tin oxide (ITO). Such a sunshield, immediately after manufacture, has solar absorptivity .alpha., averaged over the visible spectrum, between 2.5 and 25 microns, of about 0.3, an emissivity (.epsilon.) of about 0.8, and a surface resistivity in the range about 10.sup.6 to 10.sup.8 ohms per square. It has two-way RF insertion loss of 0.24 dB.
It has been discovered that exposure of the above described single-layer sunshield to a fluence of charged particles and solar ultraviolet radiation causes a gradual degradation. The on-orbit data, together with simulation data, suggest that in the course of a 10-year mission, .alpha. increases from about 0.3 to about 0.85, and surface resistivity increases to about 10.sup.9 ohms per square. Such an increase in absorptivity may cause the single-layer sunscreen to produce infrared radiation, which may cause the antenna reflector to overheat. The increase in surface resistivity may result in ESD. New generations of satellites are intended to have mission durations much exceeding ten years, so the prior art sunscreen cannot be used. An improved sunscreen is desired.


A system for configuring a network topology in a data center is disclosed. The data center includes nodes having ports capable of supporting data links that can be connected to other nodes. The system includes a memory and a processing unit coupled to the memory. The processing unit receives demand information indicative of demands between nodes. The processing unit determines a set of constraints on the network topology based on the nodes, feasible data links between the nodes, and the demand information. The processing unit determines an objective function based on a sum of data throughput across data links satisfying demands. The processing unit performs an optimization of the objective function subject to the set of constraints using a linear program. The processing unit configures the network topology by establishing data links between the nodes according to results of the optimization.

Cloud computing and its applications are effecting a qualitative shift in the way people communicate and share information. Making data available as it is requested from many different sources by many different users involves requesting and receiving data that is routed through and from datacenters according to complex routing schemes across complex network topologies. Inefficiently designed network topologies can lead to data bottlenecks and potential degradation or disruption of data availability. Current data centers contain predetermined topology structures for switching and interconnecting Internet data to a given destination.

Logical topology in a dynamic data center network


Low temperature electrical solder compositions (by weight percent) having between 45-60% Sn; 25-40% Pb; 5-15% Bi; and 0.5-2.5% In. Preferably, the solder compositions have a melting temperature of about 154.degree.-162.degree. C. The solder compositions have microstructure similarly to Sn/Pb eutectic microstructure which makes them have excellent properties like higher yield strength and better creep resistance providing long term reliability to solder joints.

In electronics manufacturing, solders provide inexpensive, mass-producible and generally reliable interconnections to complete the electronic circuitry between various elements that make up an electronic assembly. Solder joints provide electrical interconnections and serve as the mechanical attachment of the electronic components to the printed circuit board and also serve a critical heat transfer function as well. Soldering make these connections at temperatures just below those that would cause damage to some of the elements of the assembly and substrate materials.
Reflow soldering is the predominant soldering method for Surface Mount Technology (SMT) assemblies. This technique provides an opportunity to handle a wider range of electronic assemblies than were possible with wave soldering. Eutectic solder, 63% Sn/37% Pb solder (melting temperature being 183.degree. C.) is commonly used for reflow soldering with peak reflow temperature of 210.degree.-220.degree. C. In order to use low cost thermoplastic substrate materials and some temperature-sensitive components for integration of many of such components in a small area as perhaps attached to an automotive dashboard, it is required to reflow at lower peak temperatures than 220.degree. C.
It is known that eutectic 63 Sn/37 Pb solder joints are reliable during thermal cycling between -40.degree. C. and 125.degree. C. Since maximum temperature for thermal cycling in integration applications is 105.degree. C. instead of 125.degree. C., a low temperature solder based on tin-lead eutectic and having a melting temperature 20.degree. C. lower than that of 63 Sn/37 Pb is likely to survive thermal cycling between -40.degree. C. and 105.degree. C. Low temperature solder compositions such as 43 Sn/43 Pb/14 Bi or 52 Sn/48 Bi (U.S. Pat. No. 5,573,602) can be reflowed at a peak temperature of 180.degree. C. But these solder compositions have wide pasty ranges (up to 20.degree. C.) between solidus and liquidus temperatures which can lead to damage of the solder joints during reflow soldering/cooling process. Also, such solders which might include a significant amount of indium to reduce the melting point greatly increase the cost of the solder.
It would be desirable to provide new low temperature solders with a melting temperature of less than 165.degree. C. and with a narrow pasty range, preferably being about 5.degree. C., which can provide long term reliability of solder joints and which is priced to be commercially useful for large volume applications. The present invention provides such solder compositions.


A SPECT system which scans over multiple separate scans and individually motion compensates the information obtained from each of these scans. The separate scans may be over different angular extents and may be for different purposes. One of the scans for example may be a scout scan, and the other scans may then be scans which concentrate on areas identified during the scout scan. Alternatively, the scans may all being exactly the same and stitched together after the individual motion compensation. Since each of the scans are shorter, the patient will presumably have moved less during each individual scan, and the amount of motion is hence presumably less.

In SPECT imaging, data acquisition is usually completed in a single scan. A scan usually obtains between 30 and 128 projection frames are acquired in a 180° to 360° angular range, depending upon the clinical protocols. SPECT often has a low count rate because of low system sensitivity and patient dose compared to other imaging modalities, such as CT. The SPECT scan hence takes a relatively long time, e.g., from minutes to tens of minutes Theoretically, SPECT imaging requires the patient to stay motionless during the entire scan. Any movement by the patient causes data inconsistency which may introduce motion artifacts into the final images.
However, it is very difficult to keep patients motionless during scans, and especially during longer scans. When the patient motion becomes too large, the data may not be medically usable. Patients are generally rescanned when this happens.
For example, for cardiac SPECT, ASNC guidelines specifically requires that if patient motion is larger than a certain amount at any of the projection frames, the patients need to be rescanned.
Wang et al (Wang et al 2005) used multiple acquisition of moderate length to reduce effects of radioactive decay for phantom experiments. Chen et al (Chen et al 2004) used multiple sequential scans (fast fanning) with 1 second per projection for dynamic SPECT using Teboroxime. However, neither of these works could be directly used to handle motion correction in SPECT imaging.
A number of motion correction techniques have been proposed for SPECT imaging. These efforts can be divided into two main categories. One is a hardware approach that tracks patient motion during patient scans using a tracking device and uses the motion information during image reconstruction to correct for the motion. The other analyzes the acquired data after the scan using software, where the data are acquired using the current single but relatively long scan approach.
The hardware approach is ideal for motion tracking and correction for patient studies, but the device can be complicated and expensive.
The software approaches are limited in their ability to correct for sub-frame patient motion. For example, if the scanning time for one frame is 20 seconds, and the patient moves only for the second half (10 seconds) of the acquisition of the frame, unless the data are acquired in list mode, none of the current motion correction techniques will operate properly.

Multi-short-scan technique in spect imaging


Variable intake systems are provided that include a variable intake valve shaft, potentiometer, pneumatic actuator, Manifold Absolute Pressure sensor, Throttle Position Sensor and controller. Preferred systems of the invention can monitor whether valves of a variable intake system are properly working, thereby stabilizing the operation of the variable intake system in a simplified manner and at low costs.

A variable intake system is typically configured to change the length of an intake passage extended to the combustion chamber according to the engine state. The variable intake system, therefore, lengthens the intake passage during a low speed and light load for increasing the intake inertia and intake efficiency. Conversely, during a high speed and heavy load, the variable intake system shortens the intake passage to increase the intake efficiency by decreasing the intake resistance.
Conventional variable intake systems change the passage of the intake through use of valves. However, if the valves fail to operate properly, significant amounts of toxic materials can accumulate in the engine exhaust gas and deteriorate engine performance. This in turn can require the time and expense of regular inspections of the valves.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement of any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.

Variable intake system monitoring apparatus


In a multimedia system, such as a video-on-demand server, a file with data is stored in a series of successive clusters which may be distributed across the disc. A cluster consists of physically successive sectors which can be read in blocks by a user application. By repeating a part of the data at the end of a cluster at the beginning of the next cluster, the system enables reading of a block of sectors from an arbitrary sector, said block and the subsequent blocks nevertheless being accessible by way of one seek operation. The interactive response time is thus substantially improved in situations in which the user requests an arbitrary data fragment.

This invention relates to a method of storing data in a file, the file being composed of a series of logically successive clusters, data sectors in a cluster being stored one-to-one in physically successive storage sectors of the cluster.
The invention also relates to a system for storing data in a file, which system comprises a file system for storing the file which comprises a series of logically successive clusters, data sectors in each cluster being stored one-to-one in physically successive storage sectors of the cluster.
The invention also relates to an information carrier provided with a file with data, which file comprises a series of logically successive clusters, data sectors in each cluster being stored one-to-one in physically successive storage sectors of the cluster.
The invention also relates to a method of fetching data from a file which comprises a logically successive series of clusters, data sectors in each cluster being stored one-to-one in physically successive storage sectors of the cluster, the storage sectors in a given cluster being read by blocks in order to fetch each time some of the data sectors.
The invention also relates to a system for making data available to a user, the system comprising a file system for managing a file which comprises a series of logically successive clusters, data sectors in each cluster being stored one-to-one in physically successive storage sectors of the cluster.
Such a system for making data available to a user is known for so-called video-on-demand servers. A server of this kind comprises one or more discs on which files are stored. A file then contains a film which the server presents to a user on demand. In the known system a file comprises a number of clusters which have a logic order and which may be distributed on the disc. A cluster comprises physically successive sectors with the data of the file. The sectors with the data of the file are fetched from the disc by blocks so as to be placed in a buffer wherefrom the data are presented to the user at a rate which corresponds to the timing of the film. The size of a block equals the size of the buffer, so that the buffer is always completely filled. The system has two buffers for a user: while the first buffer is filled with data being presented to the user, the second buffer is available so as to be filled with the next block from the disc. The cycle of the scheduler of the system is such that the next block is present in the second buffer before all of the data in the first buffer have been presented. At that instant the first and the second buffer change functions and the process is repeated. Fetching a block for the buffer in the known system generally requires one seek operation by the head on the disc, because the sectors to be fetched are physically successively arranged in the cluster. The length of each cluster is a multiple of the length of the block, so that the last block of a cluster can also be fetched by way of one seek operation.
The known system has a number of possibilities for interaction whereby the user can control the showing of the relevant movie, for example fast showing of the film or jumping to a given point in the film. Consequently, at a given instant the user may demand data which commence at an arbitrary position within a cluster. The starting position of a block within a cluster, however, can be chosen to be situated only in a position amounting to a multiple of the size of the block so that it is ensured that the remaining part of the cluster can be read in an integer number of blocks. The block containing the demanded data is fetched and arranged in the first user buffer. Because of the restrictions imposed as regards the starting position of this block, the block will often contain an amount of data preceding the demanded data. Because in that case the buffer only partly contained data to be presented to the user, there is a risk of the buffer becoming empty before the scheduler has executed the next cycle. Therefore, before the user receives the demanded data, the system fetches not only the block containing the relevant data but also the next block and places the latter block in the second buffer. The presentation of the buffered data to the user commences only after that. Consequently, the scheduler must execute two cycles between the instant at which the user demands the data and the instant at which the user receives the data. This imposes a long waiting period for the user.

System with data repetition between logically sucessive clusters


An information processing apparatus includes a communication unit configured to perform communication with a specific-firmware-information transmitting apparatus and a firmware providing server through a network; and a control device. The control device is configured to establish a session, between the information processing apparatus and the specific-firmware-information transmitting apparatus, according to a communication protocol enabling server push and establish a connection with the specific-firmware-information transmitting apparatus in the established session; acquire specific-firmware-information, wherein the specific-firmware-information includes at least specific-firmware location-information indicating a location of the specific firmware to update firmware of the information processing apparatus to the specific firmware; acquire the specific firmware from the firmware providing server indicated by the specific-firmware location-information, based on the specific-firmware location-information included in the acquired specific-firmware-information; and update the firmware.

There have been proposed a variety of firmware updating methods for a variety of information processing apparatuses having network accessing functions.
There is disclosed a technology for using an information processing apparatus to access the Internet, search for update information, access to the website having an uniform resource locator (URL) obtained by the searching, and download software of an update target.

Information processing apparatus, relay server, information relay method, non-transitory computer-readable medium storing information relay program, and communication system