A method of decoding interleaved Reed-Solomon codes to achieve an improved performance for burst errors is described. The method takes advantage of both interleaving and erasure decoding to increase the error correcting capability of a system without necessarily depending on channel reliability information. The observed correlation of burst errors in interleaved systems is advantageously used to achieve an improved error-correcting system, wherein a first code word is decoded, and the error locations in the first codeword are used to determine erasures for the remaining code words in the same interleaving block, and finally, decoding the remaining code words in parallel.

Referring to the drawings, FIG. 1 (PRIOR ART) depicts a typical system 100 for encoding and decoding data. Original information (typically, digital data) from a source is encoded using an encoder 102 and transmitted over a communication channel (or stored on a storage device) 104. It is assumed that like all practical systems, the transmission channel is noisy (or the storage medium has errors), and this channel noise causes symbol errors in the words received at the end of the transmission channel. A symbol error is said to occur if any one or more bits in a symbol (for example, a byte) are wrong. The data so transmitted (or stored) is thereafter retrieved and decoded using a decoder 106 to reproduce the original information.
To ensure accurate storage, retrieval and transmission of data, a robust mechanism for checking and correcting errors is needed. Original information may be corrupted when it is transmitted or stored for subsequent retrieval. Sources of corruption in data include a noisy transmission channel, a scratch on a digital storage device such as a compact disk, and the like. The number of symbols any two code words are separated is called the "distance," or, more commonly, the Hamming distance, between the two code words. A common measure of the error-correcting capability of a system is the minimum distance dmin between valid code words.
It is well known that adding redundant information to data can help ensure accuracy of stored or transmitted information. Every k-symbol block of code word can be encoded into an n-symbol block (n>k) by adding n-k redundant symbols. The simplest error-correcting code is simply to repeat everything several times and then use a majority vote or other method to recover the original information from the corrupted data. But this "brute force" information recovery method does not achieve the goal of a high-speed, high-density information processing system.
Channel errors can occur at randomly isolated locations or in localized finite-length sequences. The latter are known as burst errors. A sequence of burst errors may affect many symbols in one code word and cause the decoder to fail to retrieve the original information from a corrupted code word. In J. Chen and P. Owsley, "A burst-error-correcting algorithm for Reed-Solomon Codes," IEEE Trans. on Information Theory, vol. 38, no. 6, November 1992, at pp. 1807-12 an algorithm for correcting burst errors was presented, but it is effective only for correcting a single burst in each code word.
A more efficient technique, known as interleaving, can be used to extend the capability of linear block codes. In this technique, several code words are generated simultaneously and stored in a memory matrix row-wise. These code words are then transmitted across a channel column-wise. In this way, a burst of symbol errors is distributed among multiple received words and a fewer errors occur in each received word. FIG. 2 illustrates an 8-bit interleaved system, where each row corresponds to one code word and the code word matrix is transmitted column-wise. In this example, a burst error across 11 symbols (shown shaded in the figure) is spread such that it causes maximally 2 symbol errors in each received word.
Reed-Solomon (RS) codes is helpful in correcting burst errors, where a series of bits in a code word are received in error. The advantage with RS codes is that they provide a high coding gain at a high code rate (k/n). This means that an RS decoder can recover from more errors with less redundant symbols. Stated alternatively, RS codes allow a target Bit Error Ratio (BER) to be achieved with a lower transmitter output power. RS codes were first proposed in a classic 1960 paper entitled "Polynomial Codes over Certain Finite Fields" by Irving S. Reed and Gustave Solomon. RS codes are based on a specialist area of mathematics known as finite fields or Galois fields. They are a subset of BCH codes and are linear block codes with a wide range of applications in digital communications—wireless or mobile communications including cellular telephones, microwave links, satellite communications, digital television, high-speed modems (ADSL, xDSL)—and storage systems including compact disk, DVD, bar codes and others.
Interleaved RS decoders have been found to be useful in satellite and optical communication systems as well as in storage applications. When interleaving is used, it is very likely that received words in one interleaving block have the same error locations. This observation was used in a method presented in V. Y. Krachkovsky and Y. X. Lee, "Decoding for Iterative Reed-Solomon Coding Schemes," IEEE Trans. on Magnetics, vol. 33, no. 5, September 1997, pp. 2740-42 ("Krachkovsky et al."), where all check symbols in each row code are combined to find a "covering error locator polynomial" that covers all possible error locations in every code word.
In systems where burst errors are common there is a demand for large coding gain and a very small tolerance for increase in hardware complexity. Accordingly, there is a need for an improvement in the art.

Error-erasure decoding of interleaved reed-solomon code


A communication link includes a base unit and a remote unit that each include a transmit aerial and a receive aerial. These units communicate via magnetic inductive fields. The transmit aerial may be an array that shapes the field to transmit in front of the base unit to minimize interference between adjacent base units. Transmission from the base unit to the remote unit preferably uses magnetic inductive fields that are orthogonal to the magnetic inductive fields that transmit from the remote unit to the base unit. Accordingly, the aerials include aerials for receiving and transmitting in such orientations. A tri-axial array includes three aerials that are orthogonal to each other to allow the aerials to be driven by currents that are phase shifted and amplitude modulated so that the plane of the field is selectively tilted to maximize coupling between the base unit and remote unit. Such tilting allows the user of the remote unit to move relative to the base unit and maintain maximum coupling.

Local wireless communication systems typically use ultrasound, radio frequency or infrared carriers to transmit data between transmitters and receivers. These systems have scattering of the carrier which interferes with nearby transmitters and receivers. Ultrasonic and infrared systems require a line-of-sight communication channel between transmitters and receivers. The radio frequency system also has a long range because of the 1/r decay of the transmitted signal.
Magnetic inductive systems have been used in commercial applications, such as audio loops in buildings, direct speech communication through security screens, and lowrate data links from underground to equipment on the surface. The security screens typically include coils built into desk mats on both sides of the screen.
Local wireless communication systems, such as telephone systems, include a wireless audio headset worn by a user. The user's workstation communicates voice data between a telephone line and the headset. Conventional systems transmit data from the workstation over a wide area adjacent to the workstation. This data may interfere with nearby workstations.
It is desirable to have a communication system, such as a telephone headset, that may be operated in a dense office environment with low interference between adjacent work stations. It is also desirable to have a communication system that allows the user to move within a work area around the work station without a loss of or a break in the communication link.
Inductive aerials inherently amplitude modulate signals transmitted through an inductive link between the inductive aerials. At lower frequencies, changes in frequency of the communication signal due to intended modulation of the communication signal when added to the amplitude modulation from the communication link generate large percentage changes in amplitude that compromise the dynamic range of the system. In particular, this compromise includes degraded demodulating or decoding performance of a receiver.
It is desired to reduce the effects of the frequency dependent nature of the sensitivity of inductive aerials on the performance of an inductive communication link. It is desired that such reduction in frequency dependence include both the receiving and transmitting aerials. The operating frequency range of a communication system typically is controlled by a governmental regulatory agency. It is also desired the operating frequency of such a system be extended to lower frequencies to thereby use a -larger portion of the limited spectrum window.

Aerial arrays for inductive communications systems


A self-expanding medical occlusion device treats a heart defect in a patient and is inserted into the body in minimally invasive fashion using a catheter system, and includes a braiding of thin threads which exhibits a first preliminarily definable shape as the occlusion device is being inserted into the patient's body and a second preliminarily definable shape in the implanted state, whereby the occlusion device is in a collapsed state in the first shape of the braiding and in an expanded state in the second shape of the braiding. The threads of braiding are composed of a shape memory polymer composite such that braiding deforms from a temporary shape to a permanent shape in consequence of an external stimulus, whereby the temporary shape is given in a first profile form of the braiding and the permanent shape is given in a second profile form of the braiding.

1. Field of the Invention
The present invention relates to a self-expanding medical occlusion device for treating heart defects in patients, in particular closing abnormal openings in tissue, whereby the occlusion device is introduced into the body of a patient in minimally invasive fashion using a catheter system and consists of a braiding of thin threads, whereby the braiding exhibits a first preliminarily definable shape as the occlusion device is being inserted into the patient's body and a second preliminarily definable shape in the implanted state of the occlusion device, whereby the braiding of said occlusion device in the first profile form is in a collapsed state and the braiding in the second profile form is in expanded state.
2. Description of the Related Art
The principle behind this type of occlusion device is known to at least some extent in medical technology. For example, an occlusion device for treating septum defects is known from DE 10 338 702 of Aug. 22, 2003, consisting of a braiding of thin wires or threads and given a suitable profile in a molding and heat treatment process. The known occlusion device has a proximal retention area which is particularly distinctly flat, a distal retention area, and a cylindrical crosspiece between said proximal and distal retention areas. The ends of the wires forming the braiding converge into a holder in the distal retention area. This is hence designed as such so that the two retention areas of the known occlusion device will position on the two sides of a shunt to be occluded in a septum, usually by means of an intravascular surgical procedure, while the crosspiece will transverse the shunt.
Medical technology has long endeavored to be able to occlude septal defects, for instance atrioseptal defects, by means of non-surgical transvenous catheter procedures, in other words, without having to perform an operation in the literal sense. Various different occlusion systems have been proposed, each with their own pros and cons, without any one specific occlusion system having yet become widely accepted.
In making reference to these different systems, the following will use the terms "occluder" or "occlusion device." In all interventional occlusion systems, a self-expanding umbrella system is introduced transvenously into a defect to be occluded in a septum. This type of system might comprise two umbrellas: one, for example, positioned at the distal side of the septum (i.e. the side furthest from the median plane of the body/heart) and one at the proximal side of the septum (i.e. the side closer to the median plane of the body), whereby the two umbrella prostheses are subsequently secured to a double umbrella in the septal defect. Thus, in the assembled state, the occlusion system usually consists of two clamped umbrellas connected to one another by means of a short bolt transversing the defect.
However, a disadvantage to such prior art occlusion devices turns out to be the relatively complicated, difficult and complex implantation procedure. Apart from the complicated implantation of the occlusion system in the septal defect to be occluded, the umbrellas utilized are susceptible to material fatigue along with fragment fracture. Furthermore, thromboembolic complications are frequently to be anticipated.
In order to enable the inventive occlusion device to be introduced by means of a surgical insertion instrument and/or guidewire, a holder is provided at the end of the distal retention area which can engage with the insertion instrument and/or guidewire. It is thereby intended that this engagement can be readily disengaged after positioning the occlusion device in the defect. For example, it is possible to devise the braiding at the end of the distal retention area of the occlusion device in such a manner so as to create an internal threading in the holder to engage with the insertion instrument. Of course, other embodiments are naturally also conceivable.
With another type of occlusion device, the so-called Lock-Clamshell umbrella system, two stainless steel preferably Dacron-covered umbrellas are provided, each stabilized by four arms. This type of occluder is implanted into the patient through a vein. However, seen as problematic with the Lock-Clamshell occluder is the fact that the insertion instruments necessary to implant the device need to be of relatively large size. A further disadvantage seen with other systems, for example the Amplatz occluder, is that many different occluder sizes are needed in order to cope with the respective dimensions of the septal defects to be occluded. It thus turns out that the umbrellas do not flatten out completely in the inserted state if the length or the diameter of the crosspiece inserted into the defect is not of an optimum match. This results in incomplete endothelialization. It has furthermore been shown that many of the systems implanted into patients' bodies exhibit material fatigue and fractures in the metallic structures due to the substantial mechanical stresses over a longer period. This is especially the case given permanent stress between an implant and the septum.
In order to overcome these disadvantages, self-centering occlusion devices have been developed which are inserted into the body of the patient and introduced into the septal defect to be occluded by way of a minimally invasive procedure, for example using a catheter and guidewires. Their design is based on the principle that the occlusion device can be tapered to the dimensions of the insertion instrument and/or catheter used for the intravascular procedure. Such a tapered occlusion device is then introduced by catheter into the septal defect to be occluded, respectively into the shunt of the septum defect to be occluded. The occluder is then discharged from the catheter, upon which the self-expanding umbrellas, retention plates respectively, subsequently unfold against the two sides of the septum. The umbrellas in turn comprise fabric inserts made from or covered by, for example, Dacron, with which the defect/shunt is occluded. The implants remaining in the body are more or less completely ingrown by the body's own tissue after a few weeks or months.
An example of a self-centering occlusion device of the type specified is known from WO 99/12478 A1, which is a further development of the occlusion device known as the "Amplatz occluder" in accordance with US printed U.S. Pat. No. 5,725,552. Same consists of a braiding of a plurality of fine, intertwined nitinol wire strands in the shape of a yo-yo. Each braiding is produced in its original form as a rounded braiding having loose wire ends both at its leading end (its proximal side, respectively) as well as at its trailing end (its distal side, respectively). During the subsequent processing of the rounded braiding, each of these loose ends must then be gathered into a sleeve and welded together. After the appropriate processing, both the proximal side as well as the distal side of the finished occluder exhibit a protruding collar. Dacron patches are sewn into the distal and proximal retention umbrellas and the interposed crosspiece. Because of the memory effect exhibited by the nitinol material used, the two retention umbrellas unfold by themselves upon exiting the catheter, initially in a balloon-like intermediate stage, whereby the retention umbrellas ultimately positioned on the two sides of the septum eventually assume a more or less flattened form. The crosspiece centers itself automatically into the shunt to be occluded during the positioning of the umbrellas.
The shape memory nitinol material known from prior art occlusion devices and that as previously described has, however, proven to have certain disadvantages with respect to occlusion devices. Nitinol, which is an atomistic alloy of nickel and titanium, is only conditionally suitable as a shape memory material for medical occlusion devices because the maximum deformation for nitinol between the first preliminarily definable shape given as the occlusion device is being inserted into the body of the patient and the second preliminarily definable shape given when the occlusion device is in implanted state only amounts to about 8%. In other words, this means that the shape memory nitinol material is only conditionally suitable for collapsing an occlusion device as small as possible for the implantation procedure. Hence, the implantation procedure when using a medical occlusion device which has braiding made from nitinol is not a particularly gentle one on the patient. Moreover, being an alloy of nickel and titanium, nitinol constitutes a permanent foreign body such that once in the implanted state, relevant defense system reactions can be expected from the body.
On the basis of the problematic task as set forth, which is in particular coupled with the use of nitinol as a shape memory material for medical occlusion devices, the task on which the present invention is based is that of improving upon a self-expanding medical occlusion device of the type specified at the outset to afford the patient a gentler implantation of the device.


In one embodiment, techniques provide a mechanism for tracking wavelengths in a DWDM network. In particular, embodiments of the present invention also provide for connection tracking using a slowly modulated pilot tone in a DWDM network without dedicated hardware for the generation and the diction of the tone.

The present invention relates to optical systems and, more particularly, to systems and methods for tracking wavelength communication channels through WDM (Wavelength Division Multiplexing) systems.
In WDM systems, multiple optical signals having different wavelengths share an optical fiber, each wavelength defining a particular communication channel. WDM systems have many advantages in implementing optical communications including increased capacity and the ability to use passive optical components to redirect all, or a portion, of the data flowing along a fiber. In a stricter sense, WDM refers to an ITU (International Telecommunications Union) standard that includes the specification of the particular channel wavelengths and the spacing between these channels. DWDM (Dense WDM) refers to a more recent ITU standard in which the channel spacing is tighter with more wavelength channels packed into an optical fiber. The term WDM as used herein refers to the first, more inclusive sense such that is includes both the ITU WDM and DWDM standards, unless specifically stated otherwise.
When transmitting optical signal from a source to a destination, the endpoints of the connections are established and known. However, in large networks, such as a global telecommunication network, there are many possible paths or routes exist that will deliver the data from the source to the destination. In any telecommunication network, it is critical to managing the network to track the route through the network for each connection.
Tracking occurs in the physical domain without reliance upon data maintained by the network system management or by node software. Because of the critical role that route tracking plays in maintaining the reliability of the telecommunication network, tracking must be immune to configuration errors, software failures, as well as hardware (switch) failures.
Typically, information in a frame header contains an identification sequence unique for each node in a communication route that each node along the route appends to the frame header. To identify the route, it is only necessary to extract the identification sequence. However, in WDM networks, the inability of the WDM hardware to look into the frame encoded in the wavelengths exacerbates the problem of route tracking because the header information is unavailable. Thus, while route tracking identification inside SONET/SDH or G.709 frames may suffice to detect a source-to-destination misconnection, it is not sufficient to find the route through the interior of the network.
One traditional way to implement route tracking in WDM networks is to use a fast pilot tone mechanism, the mechanism and operation of which are well known in the art. However, such a mechanism requires dedicated hardware for the generation and the diction of the tone. With a relatively fast modulation of the carrier signal, i.e., at a frequency low enough to avoid disturbing the signal data rate (currently 1 Gbps and higher) but high enough to pass through the automatic power control loops in the amplifier and other network equipment, a route can be tracked through a WDM network. Unfortunately, pilot tones require specialized and expensive hardware for generating, as well as detecting, through the network. It is also very difficult to add such hardware to existing WDM networks deployed without such specialized hardware. Another disadvantage that arises with the use of pilot tones is the degradation of the optical signal and the introduction of jitter.
What is needed is a mechanism for tracking wavelengths in a DWDM network without specialized hardware. An inexpensive and flexible mechanism that has maximum optical performance with functional flexibility is preferred.

Mechanism for tracking wavelengths in a DWDM network without specialized hardware


A method of forming a thin film includes coating one side of a transferring stamp including a hydrophilic polymer layer with a hydrophilic solution to form a transfer layer, and transferring the transfer layer to the substrate.

1. Field
Some example embodiments provide a method of forming a thin film, an electronic device, and a method of manufacturing the electronic device.
2. Description of the Related Art
An electronic device such as a solar cell, an organic light emitting diode, and the like includes a plurality of thin films such as a conductive thin film, an insulating thin film, and a semiconductor thin film. The thin film may have thin film characteristics depending on a method of forming the same.
For example, a solar cell is a photoelectric conversion device that transforms solar energy into electrical energy. The solar cell produces electrical energy by absorbing solar energy in a photoactive layer including a p-type semiconductor and an n-type semiconductor, generating an electron-hole pair (EHP) therein, transferring the generated electrons and holes to the n-type semiconductor and p-type semiconductor, respectively, and collecting the electrons and holes in each electrode.
The solar cell may further include an additional thin film between a photoactive layer and an electrode in order to increase mobility of the electrons and holes. Electrical properties of the thin film may be changed depending on a method of forming the thin film, and may have an effect on efficiency and life-span of a solar cell.

Method of forming a thin film and an electronic device

Research & Business Foundation of Sungkyunkwan University Sungkyunkwan University


A mounting apparatus includes a bracket and a pivoting member. A first sliding slot, a second sliding slot, a first guiding slot and a locating hole are defined in the bracket. A pivoting hole, a first guiding portion, a second guiding portion and a resisting wall are located on the pivoting member. A locating block is positioned on the resisting wall. A fastening member and a pivoting portion are configured to be positioned on a hard disc drive. The pivoting portion is passed through the pivoting hole, the first guiding portion is slid in a second guiding slot in the hard disc drive, the fastening member is slid in the first sliding slot. The pivoting portion is slid in the second sliding slot, the second guiding portion is slid in the first guiding slot, the resisting wall is rotated until the locating block is locked in the locating hole.

1. Technical Field
The present disclosure relates to a mounting apparatus assembly.
2. Description of Related Art
Conventional hard disc drives are fixed to a bracket of a computer case by rivets or screws. Fixing the hard disc drives to the bracket may be laborious and time consuming.
Therefore, there is a need for improvement in the art.

Zhongshan Innocloud Intellectual Property Services Co., Ltd.


The disk device according to one embodiment includes magnetic disks, a magnetic head, a ramp, and a suspension. The suspension includes a sliding portion provided on a load beam. The suspension rotates about a second rotation axis between a load position and an unload position. The ramp includes a wall and a protrusion. The wall has a first support surface that supports the sliding portion when the suspension is located in the unload position. The protrusion includes a second support surface and an intermediate portion. The second support surface faces the magnetic head when the suspension is located in the unload position. The intermediate portion is located between the wall and the second support surface. The intermediate portion includes a first portion and a second portion. The second portion is located between the first portion and the first support surface in the radial direction of the second rotation axis.

A disk device such as a hard disk drive (HDD) includes, for example, magnetic disks, magnetic heads, suspensions, and ramp. The magnetic heads are held by the corresponding suspensions. Each suspension rotates between a load position where the magnetic head is located on the surface of the magnetic disk and an unload position where the suspension is held by the ramp.
The ramp has, for example, a wall and protrusions protruding from the wall between two magnetic heads in the unload position. Each of the protrusions serves to restrict the two magnetic heads from coming into contact with each other.
As the number of magnetic disks increases in the disk device, the interval at which adjacent magnetic disks are arranged generally decreases. Each of the protrusions may be set to a thinner thickness according to the decreased interval, which may cause difficulty in manufacturing the ramp.

Disk device having ramp that includes protrusion

Toshiba Electronic Devices & Storage Corporation


Apparatus and methods for evaporating metal onto semiconductor wafers are disclosed. One such apparatus can include an evaporation chamber that includes a wafer holder, such as a dome, and a test wafer holder that is separate and spaced apart from the wafer holder. In certain implementations, the test wafer can be coupled to a cross beam supporting at least one shaper. A metal can be evaporated onto production wafers positioned in the wafer holder while metal is evaporated on a test wafer positioned in a test wafer holder. In some instances, the production wafers can be GaAs wafers. The test wafer can be used to make a quality assessment about the production wafers.

1. Field
The disclosed technology relates to systems for processing semiconductor substrates and, in particular, to systems for evaporating metal onto semiconductor substrates.
2. Description of the Related Art
Processing of semiconductor substrates, such as GaAs wafers, may include depositing a relatively thin film of metal onto the substrates by evaporation. Evaporation may be accomplished by heating a metal source and having the resulting metal vapor travel through a vacuum onto the substrate. The metal vapor may then condense on the substrate to produce a thin film of metal. The thin film may be used for a variety of purposes, such as serving as a contact for a collector, a base, and/or an emitter of a bipolar transistor.
While manufacturing wafers that will be used to make production parts, a test wafer may also be processed in order to make a quality assessment associated with the production parts and/or to ensure that processes, such as evaporation, were carried out within acceptable bounds. Small changes in environment may noticeably impact performance and/or reliability of end products produced from semiconductor wafers. Thus, the test wafer can be positioned in tools, such as an evaporator, so that the test wafer can be exposed to substantially the same processing environment as production wafers. As wafer diameter increases, fewer wafers can be positioned within the same amount of space. This leaves less space for test wafers, which may take away valuable space from production wafers.
While evaporation onto substrates takes place, sensors, such as crystal monitor sensors, may monitor conditions of evaporation. For example, a crystal monitoring system can detect a deposition rate and/or thickness of metal deposited onto the substrate. For accurate measurements, the crystal monitor sensor may be positioned near the production wafers so that the crystal monitor is exposed to substantially the same environment as the production wafers within an evaporation chamber. Information obtained using the crystal monitor sensor may be used to stop evaporation and prevent additional metal from being deposited onto the substrates.

Apparatus and methods for evaporation including test wafer holder


An apparatus and method are disclosed for separating articles from a group of articles. The apparatus includes a container for containing one or more articles coupled to a suitable fluidizer for suspending articles within the container and transporting articles to an induction tube. A portal in the induction tube introduces articles singly into the induction tube. A vacuum pulls articles through the induction tube separating the articles from the group of articles in the container. The apparatus and method can be combined with one or more unit operations or modules, e.g., for inspecting articles, assessing quality of articles, or ascertaining material properties and/or parameters of articles, including layers thereof.

Quality control (QC) systems and methods for inspecting small articles frequently employ destructive testing not suited to in-process and/or on-demand fabrication measurements and assessments. Destructive testing, for example, can be economically infeasible for assessing quality of batches involving substantial quantities of small (micron range) articles, e.g., nuclear fuel particles. Nor can such systems be expected to meet the demand anticipated in future high throughput production processing.
Accordingly, new material inspection systems and methods are needed to reduce the number of independent measurements needed to qualify articles in a batch and further address quality control and assessment issues and thereby meet production throughput requirements.

Article separation apparatus and method for unit operations


The invention relates to a method for activating a safety device, using a first impact sensor for generating a displacement signal which reproduces the movement of the vehicle in a direction of displacement, and a second impact sensor, arranged at a distance from the first impact sensor, for generating a displacement signal which reproduces the movement of the vehicle in the same direction of displacement. A processing device is provided, by which means the two displacement signals or signals derived therefrom can be correlated at the right time, and by which means the safety device is activated according to the predetermined correlations of the two signals.

The invention relates to a method of activating safety device devices and, more particularly, to a method of operating safety devices such as air bags, belt tighteners, rollover bars, and the like.
Methods of this type are generally known and used in every vehicle. In many cases, an impact sensor is used, which is an acceleration sensor that preferably generates a signal representative of the forward movement or forward deceleration (displacement) of the vehicle. If this sensor signal exceeds a threshold value, a signal is generated which, at a minimum, prepares the activation of the safety device. This signal has to meet several conditions. Measured according to the total duration of a vehicle impact of, for example 30 ms, the signal has to be available at an early point in time. However, the signal also has to be unambiguous. Operating conditions of the vehicle must be unambiguously recognized which are only slightly different with respect to the sensor signal course from an actual impact, but in which the safety device should specifically not be triggered (no-fire situations). One example of such an operating condition that must be recognized is an extreme stressing of the vehicle. Such an extreme stressing may occur during a fast drive over a gravel and/or pothole plagued stretch of a roadway.
It is an object of the invention to provide a method of activating a safety device which, at an early point in time, supplies unambiguous information concerning the actual behavior of the vehicle and the resulting necessity of triggering the safety device or devices.
The invention achieves this object by providing a method of activating a safety device having a first impact sensor for generating a displacement signal reflecting the movement of the vehicle in a direction of displacement, and comprising a second impact sensor arranged away from the first impact sensor for generating a displacement signal reflecting the movement of the vehicle in the same direction of displacement. A processing device is provided by which the two movement signals, or signals derived therefrom, are correlated in a time-correct manner, wherein the safety device is activated according to predetermined correlations of the two signals.
The invention is characterized essentially by the following measures. Two impact sensors are evaluated. The evaluation takes place in an isochronous manner. The sensor signals are related to one another. This relationship of the signals is not rigid, but rather variable with respect to the time and the amount. By means of the amount, for example, the installation-site-caused variation of the reaction times of the sensors are taken into account as is the response behavior of the respective sensor, which is a function of the environment of the installation site and which, in comparison to the other sensor, may also be very different. A sensor which is disposed on a rigid engine mount generates a different signal signature than a sensor which experiences a crash event over a relatively soft "active path".
In accordance with the invention, the sensor signals generated by different sensors are related to one another. "Different" may apply to the difference of the physical parameter (for example, acceleration and pressure) as well as to the mounting site, the response sensitivity, or also the response direction.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Bayerische Motoren Werke Aktiengesellschaft


A foldable bookcase includes a frame with two sidewalls pivotably connected to two vertical sides of the frame and a top board and a bottom board are pivotably connected to the top side and the bottom side of the frame. The top board, the bottom board and the two sidewalls are pivotable relative to the frame. The top board includes bosses which are engaged with holes in the sidewalls. A rear board are fixed to the top board by a bolt and stops extend from an inside of the rear board so as to be in contact with L-shaped bent edge defined in the rear side of each of the sidewalls. By this arrangement, the bookcase is easily assembled and the pivotable top board, bottom board and two sidewalls allow the bookcase to be folded into a compact size.

Conventional bookcases are made to be a one-piece structure which includes a top board, a bottom board, two sidewalls and one or two front doors. All of the parts are fixedly by nails (for wood boards) or by way of welding (for metal boards). The conventional bookcases are not convenient to be transported and occupy a lot of space which increases cost for the manufactures. As shown in FIGS. 9 and 10, a conventional foldable bookcase 80 includes a front frame 81, a rear board 83, a foldable top board 85 and a foldable bottom board 86 both are connected between the front frame 81 and the rear board 83, two sidewalls 82 and two doors 84. Each of the top board 85 and the bottom board 86 is composed of two parts 87 which are pivotably connected to each other by pivots 871 and can be folded along the connection side located at a center of the top board 85 and the bottom board 86. The other side opposite to the connection side of each of the top board 85 and the bottom board 86 are pivotably connected to the front frame 81 and the rear board 83 by connection pieces 872. The two ends of each of the parts 87 include L-shaped engaging plates 88 which are connected to holes 821 of the sidewalls 82. Therefore, the bookcase 80 can be folded into a compact size by folding the top board 85 and the bottom board 86.
Nevertheless, the folding line, i.e. the connection side is exposed and can be seen from outside of the bookcase 80 and the engaging plates 88 need extra machining processes to be made on the parts 27 of the top board 85 and the bottom board 86. The engaging plates 88 protrude from the parts 27 and exposed so that the bookcase 80 cannot meet requirements of aesthetic purposes.
The present invention intends to provide a foldable bookcase wherein the top board, the bottom board and the two sidewalls can be folded relative to the front frame. Besides, the bookcase of the present invention has no folding lines and engaging plats can be seen from outside of the bookcase.


An apparatus for attaching a gas bag cover on a part of a vehicle is provided, which comprises an attachment rib on the gas bag cover and an interlocking snap connection adapted to act on the attachment rib. The interlocking snap connection includes a locking element which is movably mounted on the vehicle part and is acted on by a spring element adapted to displace the locking element from an initial position into a locking position. The interlocking snap connection further comprises a detent mechanism which prevents the spring element from displacing the locking element when the latter is in its initial position. The detent mechanism is adapted to release the locking element during mounting the gas bag cover at the vehicle part.

The invention relates to an apparatus for attaching a gas bag cover on a part of a vehicle.
Conventional gas bag covers are attached to a vehicle part by means of an attachment device, the device being designed in the form of an interlocking snap connection adapted to act on an attachment rib formed on the gas bag cover.
A gas bag cover is for example secured to the steering wheel hub or, for covering a front passenger gas bag, to the dashboard. The European patent publication 0 669 230 A1 discloses a device of this kind for the attachment of a gas bag cover, which is in the form of a snap connection. For this purpose, hook-like attachment ribs are provided, which are formed on the inside of the gas bag cover, said ribs in the fitted condition reaching behind a vehicle part. For fitting, the gas bag cover is merely placed over the gas bag and pressed into position. The attachment ribs must be so designed that during deployment of the gas bag, the cover does not become loose or, still worse, is pulled out of its anchoring means.

Apparatus for attaching a gas bag cover on a part of a vehicle


A process for optimizing a portfolio of products produced from a crop includes the use of an objective function to determine optimized quantities of the products in the portfolio. The objective function, for example, includes quantity terms for the products. The objective function may also include additional terms such as an energy term and/or a storage term. The energy term, for example, relates to an amount of energy required to produce the products. The storage term, for example, relates to the cost of storing products. The crop, for example, may be sugarcane, and the products, for example, may be sugar, molasses, bagasse, biofuel, electricity, and/or carbon credits.

Many crop industries such as the sugar industry are becoming highly competitive due to globalization of competition. Cost effectiveness of a crop industry such as the sugar industry, for example, can be enhanced by optimally utilizing resources in the production of sugar products and by-products in different proportions in response to economic dynamics in the marketplace.
Traditionally, a crop industry such as the sugar industry has focused on the main crop product such as sugar. In the past, this strategy was justified as the other by-products (bio-fuels such as ethanol, butanol, bio-diesel or green-diesel, energy in form of electricity, bagasse, and molasses) were of secondary importance economically. In today's global economy, however, the price of the main crop product such as sugar fluctuates significantly as it is governed by global supply and demand. Also, because of the desire to decrease dependency on fossil fuels and because of an increased concern about global warming, the focus on and incentives for the production of bio-fuels have increased. The volatile prices of crude oil and electric power result in commensurate volatility in the price of bio-fuels. In addition, electric power generation using renewable sources (such as bagasse) fetches carbon credit revenues. For the sake of simplicity, the sugar industry will be considered as an example case of a crop industry.
The sugar industry has traditionally produced sugar from sugarcane juice. However, during the production of sugar, other major by-products such as molasses (the residual mass at the end of the crystallization stage) and bagasse (the fibrous residual after extraction of juices from sugarcane) are also produced. As indicated above, these by-products have traditionally been of less economical importance than sugar because of their low prices and demand.
Some sugar mills have converted molasses into bio-fuels by a fermentation process, and have converted bagasse into electricity using a co-generation method. However, because of low return on investment, the further conversion of by-products such as molasses and bagasse into sellable products like bio-fuels and electricity was not lucrative as many nations were mainly using crude oil (obtained by either domestic production or import) for their energy needs.
In today's global economy, where crude oil prices are threatening to become unaffordable, many countries are putting their efforts into developing energy self reliance as a part of their energy security strategies. Moreover, because of increased concern about global warming and stricter emission norms, both developed and developing countries are moving toward the adoption of environmentally friendly fuels. Hence, there is an increased demand for bio-fuels (fuel produced biologically) and green energy. Due to these changed circumstances, bio-fuel production and electricity generation offer additional sources of income to the sugar industry.
Sugar mills in today's changing world now have multiple economic routes for their resources. These mills can either divert the primary and/or secondary juice(s) to bio-fuel manufacturing by fermentation or they can use either or both juices for sugar production. Molasses can be either sold as animal feed and fertilizer or fermented to produce bio-fuels. Even bagasse can be burnt to produce electricity or sold as a raw material for the paper industry or fermented to produce bio-fuels. It should be noted that production of electricity is also possible from the spent wash generated during fermentation to produce bio-fuels such as ethanol. Moreover, the electricity generated using bagasse and spent wash is considered as green energy and earns carbon credits on excess energy (the energy above the internal needs of the sugar mill).
All of these economic alternatives require different time scales and processing costs and energies. In addition, government policies and regulations potentially affect the production levels of each of these end products.
Therefore, an agile decision support framework is needed. This framework should guide a crop industry such as the sugar industry to properly (i) evaluate these trade-offs under various what-if scenarios, and (ii) make optimal decisions related to the key intermediate resources, products, and by-products. Such a decision support system would help a crop industry such as a sugar mill to consistently drive its operations toward the optimization of profits and/or products and/or costs.

Computer evaluation of crop related industries


An automatic flaw removing method for long materials, comprises the steps of: inspecting long materials, such as round-bar steels and steel pipes, for surface flaws by a flaw inspecting apparatus of all section to divide the long materials into rejected materials having a flaw(s) and accepted materials having no flaw; storing information on the longitudinal position and length of each of the flaws of the rejected materials in a storage unit; sequentially carrying out the tracking of each of the rejected materials; moving a circumferential flaw probe directly connected to a grinder, to a longitudinal coordinate position of each of the flaws of the rejected materials, on the basis of the information on the longitudinal position of each of the flaws stored in the storage unit, when each of the rejected materials arrives at a flaw grinding position; rotating each of the rejected materials; identifying a circumferential position of each of the flaws by picking up a flaw indicative signal by the circumferential flaw probe; and automatically grinding each of the rejected materials, on the basis of the information on the identified circumferential position of each of the flaws and the information on the longitudinal position and length of each of the flaws stored in the storage unit. Thus, it is possible to interlock a high-speed automatic flaw inspecting apparatus with an automatic grinder to automatically remove surface flaws of long materials.

1. Field of the Invention
The present invention relates generally to an automatic flaw removing method for long materials. More specifically, the invention relates to an automatic flaw removing method, which inspects long materials, such as round-bar steels and steel pipes, for surface flaws by means of a flaw detecting apparatus of all section to automatically grind the materials having a flaw(s) on the basis of the flaw-position information.
2. Description of the Prior Art
As an example of a conventional automatic flaw removing method for long materials, Japanese Patent Publication No. 52-15054 discloses "a flaw-position defining method in a separate automatic flaw removing apparatus". In this method, a flaw inspecting apparatus is arranged so as to be separated from a grinder. In addition, during inspection, a reference point, such as a label which can be detected by optical means, is provided on a material to be processed. During grinding, the reference point is compared with the positional information of a flaw(s) detected by an optical detector to control the grinding position of the grinder.
In such a conventional method, as described above, a label is attached to a material to be detected, such as a round-bar steel, or a quick drying ink or paint is sprayed thereon. Therefore, the conventional method is not sufficient to accurately define the positions of the flaws, various flaw-patterns and so forth. In particular, it is difficult to apply the conventional method to a line of a high flaw-detecting rate (e.g., above 100 m/min), a material of a small-diameter curve and so forth.
In addition, in a case where an ultrasonic flaw detector using water is located immediately downstream of a surface inspecting apparatus, the label may be removed or the marking may run, so that it is difficult to apply the conventional method to an automatic flaw removing apparatus, which is required to have the accuracy and certainty of the position of the origin.
Moreover, during flaw detection, the material may travel while being twisted due to friction on a carrier roll and so forth. When a single reference mark is used, the flaw-position information map may also be twisted to be inaccurate, so as to cause the dislocation of the automatic grinding.

Automatic flaw removing method for long materials


An apparatus for manufacturing a polymer fiber shell from liquefied polymer is provided. The apparatus includes: (a) a precipitation electrode being for generating the polymer fiber shell thereupon; (b) a dispenser, being at a first potential relative to the precipitation electrode so as to generate an electric field between the precipitation electrode and the dispenser, the dispenser being for: (i) charging the liquefied polymer thereby providing a charged liquefied polymer; and (ii) dispensing the charged liquefied polymer in a direction of the precipitation electrode; and (c) a subsidiary electrode being at a second potential relative to the precipitation electrode, the subsidiary electrode being for modifying the electric field between the precipitation electrode and the dispenser.

The present invention relates to a method and apparatus for manufacturing polymer fiber shells via electrospinning.
Polymer fiber shells such as tubular shaped products, are used in the medical industry for various utilities including esophageal grafts, vascular grafts, stent coats and like.
Numerous methods for manufacturing polymer fiber shells suitable for medical applications are known in the art, including, for example, various injection molding methods, mandrel assisted extrusion or formation and various weaving techniques.
Production of polymer fiber shells suitable for use as vascular grafts is particularly difficult, since such grafts must withstand high and pulsatile blood pressures while, at the same time, be elastic and biocompatible.
Vascular grafts known in the art typically have a microporous structure that in general allows tissue growth and cell endothelization, thus contributing to long term engraftment and patency of the graft.
In vascular grafts, tissue ingrowth and cell endothelization is typically enhanced with increased in grafts exhibiting increased porosity. However, increasing the porosity of vascular grafts leads to a considerable reduction of the mechanical and tensile strength of the graft, and as a consequence to a reduction in the functionality thereof.
Electrospinning has been used for generating various products for medical applications, e.g., wound dressings, prosthetic devices, and vascular grafts as well as for industrial use, e.g., electrolytic cell diaphragms, battery separators, and fuel cell components. It has already been proposed to produce by electrospinning products having the appearance of shells. For example, U.S. Pat. No. 4,323,525 discloses a method of preparing a tubular product by electrostatically spinning a fiber forming material and collecting the resulting spun fibers on a rotating mandrel. U.S. Pat. No. 4,552,707 discloses a varying rotation rate mandrel which controls the "anisotropy extent" of fiber orientation of the final product. Additional examples of tubular shaped products and a like are disclosed, e.g., in U.S. Pat. Nos. 4,043,331, 4,127,706, 4,143,196, 4,223,101, 4,230,650 and 4,345,414.
The process of electrospinning creates a fine stream or jet of liquid that upon proper evaporation yields a non-woven fiber structure. The fine stream of liquid is produced by pulling a small amount of a liquefied polymer (either polymer dissolved in solvent (polymer solution) or melted polymer) through space using electrical forces. The produced fibers are then collected on a suitably located precipitation device, such as a mandrel to form tubular structures. In the case of a melted polymer which is normally solid at room temperature, the hardening procedure may be mere cooling, however other procedures such as chemical hardening or evaporation of solvent may also be employed.
In electrospinning, an electric field with high filed lines density (i.e., having large magnitude per unit volume) may results in a corona discharge near the precipitation device, and consequently prevent fibers from being collected by the precipitation device. The filed lines density of an electric field is determined inter alia by the geometry of the precipitation device; in particular, sharp edges on the precipitation device increase the effect of corona discharge.
In addition, due to the effect of electric dipole rotation along the electric field maximal strength vector in the vicinity of the mandrel, products with at least a section with a small radius of curvature are coated coaxially by the fibers. Such structural fiber formation considerably reduces the radial tensile strength of a spun product, which, in the case of vascular grafts, is necessary for withstanding pressures generated by blood flow.
Various electrospinning based manufacturing methods for generating vascular grafts are known in the prior art, see, for example, U.S. Pat. Nos. 4,044,404, 4,323,525, 4,738,740, 4,743,252, and 5,575,818. However, such methods suffer from the above inherent limitations which limit the use thereof when generating intricate profile fiber shells.
Hence, although electrospinning can be efficiently used for generating large diameter shells, the nature of the electrospinning process prevents efficient generation of products having an intricate profile and/or small diameter, such as vascular grafts. In particular, since porosity and radial strength are conflicting, prior art electrospinning methods cannot be effectively used for manufacturing vascular grafts having both characteristics.
There is thus a widely recognized need for, and it would be highly advantageous to have, a method and apparatus for manufacturing polymer fiber shells via electrospinning devoid of the above limitations.

Method and apparatus for manufacturing polymer fiber shells via electrospinning


A dual-band multiple beam antenna system for a communications satellite sharing a set of reflector antennas for the transmit and receive frequencies. One set of reflectors is common to both the downlink and uplink frequencies. The feed horns are diplexed and exhibit frequency-dependent radiation patterns that separate the phase centers over the downlink and uplink frequency bands to obtain dual-band performance. The focal point of the reflector is in close proximity to the phase center corresponding to the downlink frequency band. The phase center for the uplink frequency band is spaced a predetermined distance from the phase center of the downlink frequency band. According to the present invention, the uplink frequencies are defocused and the downlink frequencies are focused thereby creating identical radiation patterns at both frequency bands and over the coverage region of the communications satellite.

A typical communications satellite employing multiple spot beams requires a finite number of reflectors for the downlink, or transmit, frequencies and another set of reflectors for the uplink, or receive, frequencies. The two sets of reflectors usually contain about three or four reflectors and the reflectors are sized according to the frequencies. On board the satellite, the antenna farm typically consists of four offset reflector antennas for the downlink being located on one side of the spacecraft. The uplink reflectors, usually about two-thirds the size of the downlink reflectors, are located on the opposite side of the spacecraft.
Each set of reflectors employs dedicated feeds optimized over a narrow band. Each of the beams is produced by a dedicated feed horn. These payloads require a significant amount of real estate on the satellite. The east and west sides of the spacecraft are dedicated to the uplink and downlink spot beam payloads. This leaves only the nadir face of the spacecraft for other payloads. In addition to the number of feeds necessary for each set of reflectors, the large number of reflectors requires associated deployment mechanisms and support structures.
Attempts have been made to mitigate these problems. One approach is to use a single reflector for each frequency band and employ a large number of feed horns with a low-level beamforming network dedicated to each reflector. Each beam is generated by an overlapping cluster of horns (typically seven). This requires an element sharing network and a beamforming network to form multiple overlapping beams. However, any advantage gained by having fewer reflectors is overridden by the need for more feeds. This approach requires approximately thirty percent more feeds than the number of feed required for the conventional approach described above. Further, a large number of amplifiers and complex and heavy beamforming networks introduce additional cost and increased complexity to the system.
Another approach uses a solid reflector with a frequency selective surface (FSS) subreflector with separate feed arrays. The FSS subreflector transmits the downlink frequencies and reflects the uplink frequencies. In this approach, the number of main reflectors is reduced by a factor of two, but there is a need for complex FSS subreflectors, which require more volume to package on the spacecraft. In addition there is an increased loss with the FSS subreflector, which negatively impacts the overall electrical performance.
Yet another approach uses a FSS main reflector and dual-band feed horns. This approach employs one set of reflectors, where each reflector has a central solid region that is reflective to both frequency bands and an outer ring FSS region that is reflective at downlink frequencies and non-reflective at uplink frequencies. The electrical sizes of the reflector are different at the two bands and can be adjusted to achieve some beam coverage on the ground. This design approach is complex and very expensive. In addition there is still the disadvantage of losses associated with the FSS reflector.
There is a need for a reflector system that does not take up valuable real estate on board the spacecraft and at the same time is less complex and expensive than known methods.

Dual-band multiple beam antenna system for communication satellites


Circuitry for detecting snoop hits during the propagation and storage delay when transmitting a victim address to a bus cluster in a multiprocessor system. The circuitry includes stages for detecting the snoop hits during each cycle of the propagation delay. Each stage includes logic gates for comparing the wordline address with a snoop hit and for outputting a snoop hit signal upon detection of a snoop hit relating to the snoop address.

The present invention relates to an apparatus and method for cache coherency by detecting snoop hits on victim lines issued to a higher level cache in a multiprocessor system.
In a multiprocessor system, each processor has its own local cache for storing data. Each processor may write to and read from a shared higher-level cache. Therefore, each processor can access both its own local cache and the shared cache for the entire system. Cache coherency is required to ensure that two processors do not attempt to simultaneously access the same address space of the shared cache. In addition, due to propagation delays within the circuitry of each processor, cache coherency must ensure that attempts to access particular portions of a cache are prioritized.
In particular, when a processor attempts to replace a line in its local cache, it sends a victim address to its victim buffer in order to victimize an address space. At the same time, it transmits the victim address to a bus cluster, which is an internal on-chip interface between the processor and a system bus. The bus cluster manages prioritization of attempts to access the cache. Due to a propagation delay, the victim address transmitted to the bus cluster may require, for example, two clock cycles to reach the bus cluster. During those two clock cycles, another processor may attempt to access the same address space in the shared cache. If that occurs, the bus cluster will not be aware of the conflict resulting from attempts by both processors to access the same portion of the shared cache due to the two clock cycle delay. Therefore, circuitry must account for this type of conflict. In particular, a need exists for detecting snoop hits occurring on the same address space during a propagation delay when transmitting a victim address from a processor to a bus cluster in order to avoid conflicts while accessing the cache.
A method and apparatus consistent with the present invention includes receiving a victim address for a local cache in a multiprocessor system and transmitting the victim address to a bus cluster interfacing a processor with a system bus. A snoop is received during transmission of the victim address to the bus cluster, and it is determined if the snoop hits the victim address. If the snoop hits the victim address, a unique snoop hit signal is provided.
Another apparatus consistent with the present invention includes a plurality of wordlines corresponding to a victim address that was sent to a bus cluster and a snoop match line for detecting a snoop hit. Logic circuitry, connected to the plurality of wordlines and the snoop hit line, operates to determine if the snoop hit relates to the victim address that is being transmitted to the bus cluster interfacing a processor with a system bus. The logic circuitry also operates to provide a snoop hit signal if the snoop hits a victim address stored in the victim buffer and not yet issued to the bus cluster.

Apparatus and method for detecting snoop hits on victim lines issued to a higher level cache


A method and system for inspecting an object is provided. The system includes a measurement device that measures 3D coordinates of points on a surface of the object. A display is coupled to the device and is sized to be carried by an operator. One or more processors cooperate with the measurement device, to perform a method comprising: determining 3D coordinates of the points while the object is being measured; aligning an electronic model of the object to the points while the object is being measured; determining a variance between the electronic model and the points while the object is being measured; and displaying on the display an indicator when the variance exceeds a threshold while the object is being measured.

The subject matter disclosed herein relates to a three-dimensional (3D) measurement device, and in particular to a 3D measurement device operable to allow verification of geometry on a mobile scanner during the scanning process.
A 3D imager is a portable device includes a projector that projects light patterns on the surface of an object to be scanned. Typically the projector emits a coded or uncoded pattern. One (or more) cameras, having a predetermined positions and alignment relative to the projector, which record images of the light pattern on the surface of an object. The three-dimensional coordinates of elements in the light pattern can be determined by trigonometric methods, such as by using epipolar geometry. Other types of noncontact devices may also be used to measure 3D coordinates, such as those that use time of flight techniques (e.g. laser trackers, laser scanners or time of flight cameras) for measuring the amount of time it takes for light to travel to the surface and return to the device.
The measured 3D geometry may be used in some applications to verify the dimensional accuracy of the scanned object. Due to the computational intensive nature of this is done in a post-processing environment after the object has been scanned. This verification check allows the operator to determine whether the object is within specification for example. However, the operator needs to complete the scan and then align the point cloud with a model such as a computer-aided-design model for example. A time consuming process.
Accordingly, while existing 3D imagers are suitable for their intended purpose the need for improvement remains, particularly in providing a system for verifying dimensions of a scanned object while the scan is in progress. Still further improvements are desired in providing a system that can verify dimensions during an assembly, set up or construction of an object when dimensional changes may be readily performed or corrected.

Three-dimensional measurement device mobile geometry verification


Embodiments of the invention may provide for systems and methods for providing a power amplifier with integrated passive device, thereby improving the performance of the power amplifier. The power amplifier may include a signal amplification section, a power combining section, and a coupling device section that interconnects the signal amplification section and the power combining section. The signal amplification section may be implemented on a first substrate, and the power combining section may be implemented on a second substrate, where the first substrate and the second substrate may be different. The power combining section may be implemented by the integrated passive device (IPD) that may have characteristics of high performance passive device with flexibility of implementing diverse functions, including a notch filter, a low pass filter, and/or bypass capacitance for bias network. The power combining section implemented by the integrated passive device may have an improved power combining efficiency.

Currently, the power amplifier for mobile communication has been implemented using a gallium-arsenide field effect transistor (GaAs FET), gallium-arsenide heterojunction bipolar transistor (GaAs HBT), a laterally diffused metal oxide silicon (LDMOS), or a indium-gallium-phosphide heterojunction bipolar transistor (InGaP HBT). These power amplifiers can achieve the output power (Pout) and the power added efficiency (PAE) for the wireless communication; however, they have some disadvantages in requiring an additional power controller chip, additional output matching circuits, and the like.
To improve these issues, the complementary metal-oxide-semiconductor (CMOS) process has been used to implement the power amplifier, thereby offering a high level integration with power controller circuits and low cost as compared to GaAs and other traditional processes. However, the silicon (Si) substrate used in a traditional CMOS process is conductive, which increases RF loss and severely degrades the performance of passive circuit elements. Accordingly, there is a need for novel CMOS power amplifier designs that include integrated passive devices on highly resistive substrates so that the performance of the passive device is not degraded.

Systems and methods for power amplifier with integrated passive device


Methods, apparatuses and substrate assembly structures for mechanical and chemical-mechanical planarizing processes used in the manufacturing microelectronic-device substrate assemblies. One aspect of the invention is directed toward a method for planarizing a microelectronic-device substrate assembly by removing material from a surface of the substrate assembly, detecting a first change in drag force between the substrate assembly and a polishing pad indicating that the substrate surface is planar, and identifying a second change in drag force between the substrate assembly and the polishing pad indicating that the planar substrate surface is at the endpoint elevation. After the second change in drag force is identified, the planarization process is stopped. The first change in drag force between the substrate assembly and the planarizing medium is preferably detected by measuring a first change in the electrical current through a drive motor driving a substrate holder carrying the substrate assembly and/or a table carrying the polishing pad. The second change in drag force between the substrate assembly and the polishing pad may be identified by detecting a second change in the drive motor current or measuring a second change in the temperature of the planarizing solution or the polishing pad.

Mechanical and chemical-mechanical planarizing processes (collectively "CMP") are used in the manufacturing of microelectronic devices for forming a flat surface on semiconductor wafers, field emission displays and many other microelectronic substrates. FIG. 1 schematically illustrates a planarizing machine 10 with a platen or table 20, a carrier assembly 30 over the table 20, a polishing pad 40 on the table 20, and a planarizing fluid 44 on the polishing pad 40. The planarizing machine 10 may also have an under-pad 25 between the platen 20 and the polishing pad 40. In many planarizing machines, a drive assembly 26 rotates (arrow A) and/or reciprocates (arrow B) the platen 20 to move the polishing pad 40 during planarization.
The carrier assembly 30 controls and protects a substrate 12 during planarization. The carrier assembly 30 typically has a substrate holder 32 that holds the substrate 12 via suction, and a pad 34 in the substrate holder 32 that supports the backside of the substrate 12. A drive assembly 36 of the carrier assembly 30 typically rotates and/or translates the substrate holder 32 (arrows C1 and D, respectively). The substrate holder 32, however, may be a weighted, free-floating disk (not shown) that slides over the polishing pad 40.
The combination of the polishing pad 40 and the planarizing fluid 44 generally define a planarizing medium that mechanically and/or chemically-mechanically removes material from the surface of the substrate 12. The polishing pad 40 can be a conventional non-abrasive polishing pad without abrasive particles composed of a polymeric material (e.g., polyurethane), or it can be an abrasive polishing pad with abrasive particles fixedly bonded to a suspension material. In a typical application, the planarizing fluid 44 may be a CMP slurry with abrasive particles and chemicals for use with a conventional nonabrasive polishing pad. In other applications for use with an abrasive polishing pad, the planarizing fluid 44 is generally a "clean" chemical solution without abrasive particles.
To planarize the substrate 12 with the planarizing machine 10, the carrier assembly 30 presses the substrate 12 against a planarizing surface 42 of the polishing pad 40 in the presence of the planarizing fluid 44 (arrow C2). The platen 20 and/or the substrate holder 32 then move relative to one another to translate the substrate 12 across the planarizing surface 42. As a result, the abrasive particles and/or the chemicals in the planarizing medium remove material from the surface of the substrate 12.
CMP processes should consistently and accurately produce a uniformly planar surface on the substrate assembly to enable precise fabrication of circuits and photo-patterns. During the fabrication of transistors, contacts, interconnects, and other components, many substrate assemblies develop large "step heights" that create a highly topographic substrate surface. To enable the fabrication of integrated circuits with high densities of components, it is necessary to produce a planar substrate surface at several stages of processing the substrate assembly because non-planar substrate surfaces significantly increase the difficulty of forming sub-micron features or photo-patterns to within a tolerance of approximately 0.1 μm. Thus, CMP processes should typically transform a highly topographical substrate surface into a highly uniform, planar substrate surface (e.g., a "blanket surface").
In the competitive semiconductor industry, it is also highly desirable to maximize the yield of operable devices as quickly as possible. One factor of CMP processing that affects the yield of operable devices is the ability to accurately stop CMP processing at a desired endpoint. In a typical CMP process, the desired endpoint is reached when the surface of the substrate is highly planar and/or when enough material has been removed from the substrate assembly to form discrete components of the integrated circuits (e.g., shallow-trench-isolation structures, contacts, damascene lines, etc.). Accurately endpointing CMP processing is important for maintaining a high yield because: (1) subsequent processing may not be possible if the surface is not sufficiently planar; and/or (2) the integrated circuits may not operate if the discrete components are not accurately formed. For example, if the substrate is "under-planarized," shallow-trench-isolation structures may not be adequately isolated from one another. Conversely, if the substrate assembly is "over-polished," "dishing" can occur in shallow-trench-isolation structures that can cause current-leakage paths or parasitic capacitance. Extreme cases of over-polishing can even destroy sections of the substrate assembly. Thus, it is highly desirable to stop CMP processing at the desired endpoint.
One drawback of CMP processing is that it is difficult to determine when the substrate surface is both planar and at the desired endpoint elevation in the substrate assembly. In one conventional method for determining the endpoint of CMP processing, the planarizing period of one substrate assembly in a run is estimated using the polishing rate of previous substrate assemblies in the run and the thickness of material that is to be removed from the particular substrate assembly. The estimated planarizing period for the particular substrate assembly, however, may not be accurate because the polishing rate may change from one substrate assembly to another. Thus, this method may not accurately planarize all of the substrate assemblies in a run to the desired endpoint.
In another method for determining the endpoint of CMP processing, the substrate assembly is removed from the pad and the substrate carrier, and then a measuring device measures a change in thickness of the substrate assembly. Removing the substrate assembly from the pad and substrate carrier, however, is time-consuming and may damage the substrate assembly. Thus, this method generally reduces the throughput and yield of CMP processing.
In still another method for determining the endpoint of CMP processing, a portion of the substrate assembly is moved beyond the edge of the pad, and an interferometer directs a beam of light directly onto the exposed portion of the substrate assembly to measure a change in thickness of a transparent layer. The substrate assembly, however, may not be in the same reference position each time it overhangs the pad. For example, because the edge of the pad is compressible, the substrate assembly may not be at the same elevation for each measurement. Thus, this method may inaccurately measure the change in thickness of the substrate assembly.
In yet another method for determining the endpoint of CMP processing, U.S. Pat. Nos. 5,036,015 and 5,069,002, which are herein incorporated by reference, disclose detecting the planar endpoint by sensing a change in friction between a wafer and the polishing medium. Such a change of friction may be produced by a different coefficient of friction at the wafer surface as one material (e.g., an oxide) is removed from the wafer to expose another material (e.g., a metal film). More specifically, U.S. Pat. Nos. 5,036,015 and 5,069,002 disclose detecting the change in friction by measuring the change in electrical current through the drive motor for the platen and/or substrate holder.
Although the endpoint detection technique disclosed in U.S. Pat. Nos. 5,036,015 and 5,069,002 is an improvement over the previous endpointing methods, the increase in current through the drive motors may not accurately indicate the endpoint of a substrate. The detection of a single change in friction at the interface between the different materials may only indicate that at least a portion of the substrate surface is at the level of the interface. Other portions of the substrate surface, however, may be above or below the interface level and/or the interface level itself may not be planar. The apparatus and methods disclosed in U.S. Pat. Nos. 5,036,015 and 5,069,002 may accordingly indicate that at least a portion of the substrate surface is at the endpoint elevation, but they do not necessarily indicate that the substrate surface is planar. Thus, the apparatus and methods of U.S. Pat. Nos. 5,036,015 and 5,069,002 may not indicate that the substrate surface is both planar and at the endpoint elevation.

Methods, apparatuses, and substrate assembly structures for fabricating microelectronic components using mechanical and chemical-mechanical planarization processes


An embodiment relates to a polishing pad which is used in a chemical mechanical planarization (CMP) process and has excellent airtightness, wherein the polishing pad is excellent in airtightness of a window opening and thus can prevent water leakage that may occur during a CMP process.

A polishing pad for a chemical mechanical planarization (CMP) is an essential element that plays an important role in the CMP process for the fabrication of semiconductors. It plays an important role in materializing the performance of the CMP process. A polishing pad for a CMP process serves to remove unnecessary portions on a wafer and makes the surface of the wafer smooth through a uniform polishing operation during the CMP process.
In recent years, various methods have been proposed to measure the thickness of a wafer and to detect the termination point of the CMP process. For example, in order to in-situ determine the flatness of the surface of a wafer, a method has been proposed in which a window is mounted in a polishing pad, and the thickness of the wafer is measured through a reflected beam generated by the interference of a laser through the window. Several methods for mounting a window in a polishing pad have been proposed. For example, there have been proposed a method of inserting and integrating a window block in the step of forming a polishing layer (hereinafter, "a window-integrated polishing pad") (see Korean Patent No. 10-0646887) and a method in which a polishing layer is punched and a window block separately prepared is inserted into the punched hole (hereinafter, "a window-inserted polishing pad") (see Korean Patent No. 10-0903473).
Meanwhile, the window-inserted polishing pad has a disadvantage in that leakage occurs during a CMP process due to the gap between the polishing layer and the window block. It is urgent to develop a polishing pad having excellent gas tightness in order to prevent leakage that may occur in a CMP process.

Polishing pad having excellent airtightness


A method for recognizing characters includes the steps of: inputting image data; carrying out a recognition process for recognizing each character based on the image data, the recognition process including a plurality of processes, each of the plurality of processes generating a result based on independent information, wherein a recognition result with respect to each character is determined based on the result generated in each of the plurality of processes; generating a degree of belief for the recognition result with respect to each character; and outputting the recognition result and the degree of belief with respect to the recognition result. The step of generating a degree of belief includes the steps of: generating certainty data based on the independent information which is used for generating the result in each of the plurality of processes; combining the certainty data which are generated for results in the plurality of processes with each other; and generating the degree of belief based on the combination data.

The present invention generally relates to a method and an apparatus for recognizing characters, and more particularly, to a method and an apparatus for recognizing characters by which it is easy for users to appraise recognition results and to revise them.
In a conventional character recognition system, a pattern matching process is carried out so that recognition results are obtained. In the pattern matching process, a character pattern input from an input unit is compared with each reference pattern stored in a dictionary. Then a reference pattern having a low degree of difference from the input character pattern, or a reference pattern having a high degree of similarity to the input character pattern, is output as a recognition result with respect to the input character pattern. However, it is impossible in practice for any character recognition system to obtain a probability of 100% that a recognition result is correct. Thus, it becomes necessary for a user to appraise the recognition results and to revise them.
Conventionally, an optical character recognition apparatus has been proposed, for example, in Japanese Patent Publication No. 61-6430, in which each recognition result is displayed on a display unit and the displayed recognition result is colored in accordance with the degree of similarity of the recognition result to the input character pattern. According to this character recognition system, the user can appraise each of the recognition results based on a corresponding color given to each displayed recognition result.
Further, the following technique has also been proposed.
In a process for recognizing characters, pattern data and feature data for each input character are stored in a memory. Then, when the recognition result obtained by the process for recognizing characters is revised, a learning process for the dictionary to be used for recognizing characters is carried out based on the pattern data and/or the feature data stored in the memory. That is, the contents in the dictionary are updated based on the pattern data and/or the feature data for each input character.
Recently, the number of types and styles of characters which can be written on a document has increased, and the number of cases where characters located on a low quality copy must be recognized has also increased. Thus, it is difficult to increase the recognition rate by only improving the pattern matching process described above. As a result, post processes to be carried out after the pattern matching process have been studied, so that the number of the processes which must be carried out until the recognition result is obtained has increased, and the processes for obtaining the recognition result have become complex. The process for recognizing characters includes, for example, a getting out process for getting an image for one character out of a chain of characters, the pattern matching process, a language process for analyzing the input character pattern based on language rules, and the like.
In the conventional character recognition apparatus in which the processes are carried out in a complicated manner, it is difficult to accurately appraise the recognition result based on only the degree of similarity obtained by the pattern matching process.

Character recognition method and apparatus, including generation of a degree of belief


The process for manufacturing a through insulated interconnection is performed by forming, in a body of semiconductor material, a trench extending from the front (of the body for a thickness portion thereof; filling the trench with dielectric material; thinning the body starting from the rear until the trench, so as to form an insulated region surrounded by dielectric material; and forming a conductive region extending inside said insulated region between the front and the rear of the body and having a higher conductivity than the first body. The conductive region includes a metal region extending in an opening formed inside the insulated region or of a heavily doped semiconductor region, made prior to filling of the trench.

As is known, for manufacturing microsystems comprising elements obtained using different technologies, such as microelectromechanical systems (MEMS) and integrated circuits, there exists the need to electrically connect two opposite faces (front and rear) of substrates integrating electronic components or, generally, carrying passive elements and/or protection structures and/or connection structures to other substrates.
EP-A-0 926 723 describes a process for forming front-rear through contacts in micro-integrated electronic devices. According to this process, a metal contact region extends through a through opening in the chip. In detail, this process is basically made up of the following steps:    1. Formation of metal connection regions on the front of a wafer during formation of the contacts of the device; the metal connection regions are formed at the location where the connection with the rear of the wafer will be made;    2. Etching of the rear of the wafer for partial removal of the substrate in the connection locations with formation of openings passing right through the wafer;    3. Deposition of an insulating layer on the bottom and on the walls of the through cavities;    4. Removal of the insulating layer from the bottom of the cavity to obtain contact areas with the front of the wafer and with the metal connection regions;    5. Deposition or growth from the rear of a metal layer, which coats the walls of the cavities, makes electrical contact with the metal connection regions, and has surface portions on the rear of the wafer; and    6. Formation on the rear of connection regions towards the outside in electrical contact with the surface portions.
In the process described above, the biggest difficulties lie in insulating the through openings (deposition of oxides, nitrides or polymeric materials), in that they have a depth of several tens of microns and have substantially vertical walls.
EP-A-1 151 962 describes a structure for electrical connection between two bodies of semiconductor material obtained by digging trenches of a closed (annular) shape from the front of a first, heavily doped, wafer and filling the trenches with dielectric material. Next, the first wafer is thinned from the rear until the trenches are reached, so obtaining an insulated-silicon area (silicon plug), which connects the front and the rear of the wafer. Next, the first wafer is fixed to a second wafer which houses integrated components. If MEMS are made in the first wafer, it can be used as protection for the MEMS and their connection to the second wafer.
In the above structure, the need to dope the first wafer heavily to reduce resistance of the silicon plugs limits the applicability of this solution. In particular, in the first wafer, only some types of microsystems may be integrated, and normally the integration of active components is not possible.

Process for manufacturing a through insulated interconnection in a body of semiconductor material


According to this invention, silicon-based photodetectors using waveguides formed with silicide regions can have high speed and high efficiency for near IR applications. Utilizing the unique properties of silicides, the proposed method provides a simple and elegant way to implement a photodetector design in which photogenerated carriers travel perpendicular to the direction of light propagation. Therefore, the speed and quantum efficiency of the photodetector may be optimized independently. This device configuration may be implemented in one of the two approaches: (a) waveguides formed through surface silicidation of a silicon-based layer of a substrate (b) waveguides formed through silicidation of ridge waveguide side-walls of a silicon-based layer of a substrate; The use of mature silicon technology promises low cost of production and other benefits.

High-speed detectors and detector arrays are required for telecommunication systems, for high-capacity local area networks, and for instrumentation. For chip-to-chip or processor-to-processor data exchange, optical interconnects will eventually replace today's electrical methods. Many such approaches are being explored. As the number of detectors required for each application increases, low material cost, mature fabrication technology and compact design present many advantages. Compared to detectors requiring surface normal coupling, waveguide detectors are simpler to assemble.
Traditionally photodetectors with high speed and high quantum efficiency have been limited to materials with direct band-gap, such as III–V compounds. It is desirable to fabricate such devices with silicon-based materials, to benefit from the low cost and mature silicon technology. Because the light absorption in the near IR range for silicon (Si) is low it is necessary to uncouple the optical path length (quantum efficiency factor) and the distance between electrodes (speed limit factor).
Metal-semiconductor-metal (MSM) detectors are often proposed as an alternative for high-speed operation, as the speed is primarily limited by the transit time between electrodes. The distance between photodetector electrodes can be scaled down through fine line lithography. MSM detectors are described in the following publications: "140 GHz metal-semiconductor-metal photodetectors on silicon-on-insulator substrate with a scaled active layer", M. Y. Liu, E. Chen, and S. Y. Chou, Appl. Phys. Lett. 65(7), p. 887, 1994; "High-speed metal-semiconductor-metal photodetectors fabricated on SOI-substrates", K. Honkanen, N. Hakkarainen, K. Määttä, A. Kilpelä and P. Kuivalainen, Physica scripta T79, p. 127, 1999; "Comparison of the picosecond characteristics of silicon and silicon-on-sapphire metal-semiconductor-metal photodiodes", C. C. Wang, S. Alexandrou, D. Jacobs-Perkins, and T. Y. Hsinag, Appl. Phys. Lett. 64(26), p.3578, 1994. The contents of the aforementioned publications are incorporated here in by reference.
To increase the optical path length, and therefore the quantum efficiency, several approaches have been explored. Waveguide geometries, often formed on silicon-on-insulator (SOI) substrates as silicon ridges, have been used, as described in "SOI waveguide GeSi avalanche pin photodetector at 1.3 μm wavelength", T. Yoshimoto, S. G. Thomas, K. L. Wang and B. Jalali, IEICE Trans. Electron., E81-C(10), p. 1667, 1998, and "Near-infrared waveguide photodetectors based on polycrystalline Ge on silicon-on-insulator substrates" G. Masini, L Colace, G. Assanto, Optical Materials 17 (2001) 243–246, incorporated here in by reference. The collection of carriers is accomplished either by forming MSM structures on the surface of the ridge waveguides, or by grown-in pin structures.
Another approach is to use vertical cavity structures, which consist of a thin absorbing layer sandwiched between two mirrors. In the past, vertical cavities have been used successfully to build high speed, high quantum efficiency photodetectors. The mirrors were made of dielectric/silicon or Si/SiGe multi-layers through deposition. This method is described in the following publications: "Selective epitaxial growth Si resonant cavity photodetector", G. W. Neudeck, J. Denton, J. Qi, J. D. Schaub, R. Li and J. C. Campbell, IEEE Photo. Technol. Lett. 10(1), p. 129 (1998) and "Si/SiO2 resonant cavity photodetector", D. C. Diaz, C. L. Schow, Jieming Qi, J. C. Campbell, J. C. Bean and L. J. Peticolas, Appl. Phys. Lett. 69(19), p. 2798 (1996).
Buried silicide layers, embedded by wafer bonding or implant, have also been used as mirror material for vertical cavities, as described in: "A vertical cavity longwave infrared SiGe/Si photodetector using a buried silicide mirror," R. T. Carline, D. A. O. Hope, V. Nayar, D. J. Robins and M. B. Stanaway, Technique Digest of IEDM'97, p. 36.1.1 (1997) and in "Fabrication of ultra-fast Si-based MSM photodetector," M. Löken, L., S. Mantel and Ch. Buchal, Electron. Lett. 34 (10), p. 1027, 1998. The contents of the aforementioned publications are incorporated here in by reference.
However, the devices described in the prior art present several limitations described below.
In the case of MSM detectors, only the photocarriers generated near the electrodes (i.e. near the surface) can be collected through drift in the electric field. For carriers generated outside the electric field, a portion of the carriers can be collected through diffusion rather that drift, resulting in a reduction in speed. Forming MSM structures on SOI substrates with thin silicon layers may eliminate this problem. However, the responsivity becomes very low.
Waveguide structures with vertical pin junctions require a specific layer sequence, therefore are costly to make and can limit the possibilities for component integration.
For the vertical cavity structures, light is coupled in from the surface normal direction, and these detectors operate only at a set of discrete resonant wavelengths. The resonant wavelength is determined by the distance between the two mirror surfaces. To obtain high quantum efficiency at the designed wavelength, stringent control in layer thickness is required, which often is a challenge in itself.
In view of the potential advantages of a Si-based photodetector, it would be very advantageous to provide a relatively simple Si-based photodetector with high quantum efficiency and fast response. This application discloses such is a photodetector.

High speed and high efficiency Si-based photodetectors using waveguides formed with silicide for near IR applications