Method and apparatus for providing an estimate of the size of a compressed signal without actually compressing the signal. A compression estimation mechanism models the behavior of entropy encoders on the transform coefficients generated by the application of a discrete transform method on an input uncompressed signal. The compression estimation mechanism may be used to predict a lower bound and upper bound on the size of the compressed signal from the entropy encoders, or alternatively an estimated size of the compressed signal. Since embodiments use a model of the behavior of entropy encoders to predict the bounds of the compressed signal or the size of the compressed signal without performing the actual entropy encoding, the bounds or size estimate may be predicted in less time than it takes to perform full compression of the signal.

1. Field of the Invention
This invention relates to computer systems, and more particularly to data compression mechanisms, specifically transform coding mechanisms as applied to discrete signals.
2. Description of the Related Art
In computer science and information theory, data compression is the process of encoding information using fewer bits than an unencoded representation would use through use of specific encoding schemes. Discrete signals such as discretely sampled audio, video, and images are typically compressed using transform coding. In transform coding, a discrete transform is first performed on the signal to generate a set or vector of transform coefficients. Transform coefficients that are at or near zero may be discarded, and transform coefficients that are small may be coarsely quantized according to one or more quantization factors. Note that quantization may be defined as the representation of a measured value by an integer. This process concentrates meaningful information from the signal in a subset of transform coefficients, which may be referred to as the transformed signal. A lossless entropy encoding scheme or technique may then be applied to the transformed signal to generate a compressed signal, for example a compressed file. Note that transform coding is generally a "lossy" compression scheme. Further note that applications or implementations of transform coders (in hardware, software, or a combination thereof) may sometimes be referred to as "codecs".
Entropy encoding is a coding scheme that assigns codes to symbols to match code lengths with the probabilities of the symbols. Typically, entropy encoders are used to compress data by replacing symbols represented by equal-length codes with symbols represented by codes proportional to the negative logarithm of the probability. Therefore, the most common symbols use the shortest codes.
There are many discrete transform methods that may be used in transform coders. Discrete transform methods include, but are not limited to, forms of discrete Fourier transforms (DFT), discrete cosine transforms (DCT), discrete Hartley transforms (DHT), rectangular wave transforms, eigenvector-based transforms, and wavelet transforms.
Likewise, there are many entropy encoding techniques that may be used in transform coders. Entropy encoding techniques include, but are not limited to, dictionary-based techniques such as run-length encoding (RLE) and LZW encoding, statistical encoding techniques such as Huffman coding, and arithmetic coding. Note that an entropy encoding scheme in a transform coder may use a combination of two or more of the entropy encoding techniques. For example, RLE may first be applied to a signal, followed by Huffman coding.
Commonly used applications of transform coders include, but are not limited to, the JPEG, JPEG2000, and MPEG compression standards. JPEG is an image compression standard created by the Joint Photographic Experts Group that uses a two-dimensional forward discrete cosine transform (DCT, type II) to generate a transformed signal. RLE is then performed on the transformed signal, after which Huffman coding is performed. The JPEG standard also allows for arithmetic coding to be performed rather than Huffman coding. JPEG 2000 is an image compression standard created by the Joint Photographic Experts Group that uses a wavelet transform rather than a DCT transform. MPEG is a video/audio (multimedia) compression standard created by the Moving Picture Experts Group, a working group of ISO/IEC.
FIG. 1 illustrates data flow for a conventional transform coder. Inputs to a transform coder 110 may include an uncompressed signal 102 and one or more compression parameters 104. Source 100 of uncompressed signal 102 may be a digitized image (e.g., a digital photograph), a digitized audio stream or audio file, a digital video stream or video segment, etc. Note that uncompressed signal may be a subset or portion of a larger signal, for example a portion of an image, audio stream, or digital video stream. Input compression parameters 104 may include one or more variable parameters that may be used during the compression process. Compression parameters 104 may affect both the compression ratio (the ratio of the size of the output compressed signal 150 to the input uncompressed signal 102) and the quality of the compressed signal 150. Generally, the quality is directly related to the compression ratio; higher rates of compression that generate smaller compressed signals 150 tend to negatively affect the quality of the compressed signals 150.
A discrete transform is performed on the uncompressed signal 102 using a transform method 122 employed by the transform coder 110 and in accordance with the compression parameters 104 to generate a vector of transform coefficients 124. Zero and near-zero coefficients may be discarded, and small coefficients may be quantized, concentrating meaningful information from the uncompressed signal 102 into a subset of transform coefficients 124. After the discrete transform of signal 102 is performed, the transformed signal 130 may then be passed to an entropy encoder 140 that encodes the transform coefficients 124 to generate compressed signal 150. Compressed signal 150 typically goes to a destination 160, e.g. a compressed file or compressed audio or video stream.
In many applications, given an input uncompressed signal 102, an operator or user of a transform coder 110 may desire or need to know the size of the compressed signal 150. For example, a user may have a large image in an image editing application that the user wants to compress and save. The user may have a necessary or desired target size, and may want the compressed signal 150 to be close to that size. Conventionally, determining the compressed size is performed by actually performing the compression to generate the compressed signal 150. If the compressed signal 150 is too large or too small, the user may then adjust the compression parameters 104 and perform the compression again. Thus, conventionally, determining the size of the compressed signal 150 is performed by trial and error, which is time- and compute-intensive.
Some techniques have been developed for predicting the compressed size of a signal that do not require the signal to be fully compressed by the transform coder 110. However, these techniques tend to be designed for specific transform coders, particularly for predicting the performance of specific entropy encoders 140.

Method and apparatus for predicting the size of a compressed signal


A ratchet includes a spool rotatably disposed within a housing and supporting a cord having opposed cord sections extending from the housing. Tension to one cord section is initially applied by pulling on the other cord section. To increase the tension, a tool is engaged with the spool to apply a further force to increase the tension on the one cord section. In another embodiment, a cord enters the housing and into the center of a hollow shaft supporting a spool and drawn through the hollow shaft to establish an initial degree of tension on the section of the cord entering the housing. A lever cooperating with the spool turns the spool to wrap the cord about the spool and increase the tension on the cord. In a third embodiment, a cord enters a housing and extends about a spool supported within the housing and thereafter exits the housing. A pivotable lever incrementally rotates the spool to increase the tension on the cord entering the housing. To further increase the tension on the spool, a wrench or the like may engage the shaft supporting the spool in any of the ratchets described.

1. Field of the Invention
The present invention relates to ratchets and, more particularly, to heavy duty ratchets.
2. Description of Related Prior Art
Ratchets for use with cords of various types have been commercially available for a period of years. U.S. Pat. Nos. 6,068,242, 6,092,791, and Des. 362,614 are representative and are incorporated herein by reference. A ratchet of this type includes a housing having a hook or like member for attaching the ratchet to an anchor point. A spool within the housing supports a cord partially wrapped thereabout and extending from within the housing. The spool includes a ring-like arrangement of a plurality of teeth engageable by a pawl to prevent rotation of the spool in one direction. The opposed sides of the spool contacting the cord partially wrapped thereabout includes a plurality of ridges to minimize slippage of the cord on the spool. Upon exerting a pulling force on a first length of the cord extending from within the ratchet, the spool is caused to rotate to draw the second length of cord extending from the ratchet into the ratchet. Thereby, tension can be applied to the second length of cord as the first length of cord is pulled. The resulting tension force exerted on the second length of cord will tend to wedge the cord within the spool due to the ridges in the spool. Thereby, slippage of the cord about the spool due to the tension force exerted is essentially eliminated. To release the tension force, the pawl is pivoted out of engagement with the teeth to permit the spool to freely rotate in either direction.
Some variations of the above-described ratchet and those shown in the above referenced patents have been developed. However, the amount of tension force that can be applied has been essentially limited by the degree of pulling force manually exerted upon the free end of the cord. Usually, the tension force is 100 or so pounds.


An image forming apparatus according to the present disclosure has items relating to function control. The image forming apparatus includes a setting section and a classification section. The setting section sets item content for each function. The classification section classifies an item into a first item group depending on a change frequency of the item contents. The first item group is defined such that information indicating a change in item content of the group is sent to an external device.

The present disclosure relates to an image forming apparatus.
Generally, an image forming apparatus is known to provide one or more functions (for example, a printing function, a copy function, and a scanner function) to a user and be configured to allow the user to set, in each of items related to one or more functions, corresponding item content. Each of the items is provided with pieces of item content that can be selected by the user.
Meanwhile, an image forming apparatus is also known to be maintained by a service person. An image forming apparatus as an example of such an image forming apparatus includes non-volatile memory. The image forming apparatus stores in the non-volatile memory maintenance information for the service person to execute maintenance.

Image forming apparatus having items related to function control


An elevator system having a controller configured for: receiving a communication from the mobile device for a passenger, the communication including first data, wherein the first data is position data obtained by the mobile device executing a multilateration (MLAT) process with one or more proximately located telecommunication devices, rendering a first determination, from the first data, that the mobile device is proximate a first distance from the lobby, rendering a second determination, from the first determination, arrive at the lobby proximate a first time, and transmitting a communication to an elevator instructing the elevator to arrive at the lobby proximate the first time to provide elevator service.

The embodiments herein relate to elevators and more specifically to a system and method for effecting elevator service based on indoor proximity of mobile device to elevator lobby.
It may be desirable to determine whether a potential passenger is located inside a building, for example where global positioning systems (GPS) may be shielded from service, or GPS systems are otherwise inoperative or yet to be implemented. Further, an irregular shape to a building may create a challenge for tracking a person in the building.

Effecting elevator service based on indoor proximity of mobile device to elevator lobby


A method for preparing a composition including silicate mineral particles that have coloring properties in which a talcose composition, including phyllosilicate mineral particles chosen from the group formed: from the particles having the chemical formula: ((SixGe1-x)4 M3O10 (OH)2, the particles having at least one interlayer space and having the chemical formula: (SixGe1-x)4 M3-ε O10 (OH)2, (M′m+)ε′.nH2O: -M having the formula Mgy(1)Coy(2)Zny(3)Cuy(4)Mny(5) Fey(6)Niy(7)Cry(8); -M′m+ designating at least one interlayer cation, the silicate mineral particles having a thickness of less than 100 nm and of which the largest dimension is less than 10 μπι, is brought into contact with a dye solution, including dye cations, of at least one element chosen from the transition metals, the lanthanides and the actinides. The composition obtained by this method is also described.

Phyllosilicates are composed of an irregular stack of elementary lamellae of crystalline structure, the number of which varies from several units to several tens of units. Among the phyllosilicates (lamellar silicates), the group comprising especially talc, mica and montmorillonite is characterized by the fact that each elementary lamella is constituted by the association of two tetrahedral layers situated on either side of an octahedral layer. This group corresponds to the 2:1 phyllosilicates, which include especially the smectites. In view of their structure, the 2:1 phyllosilicates are also described as being of the T.O.T. (tetrahedron-octahedron-tetrahedron) type.
The octahedral layer of the 2:1 phyllosilicates is formed of two planes of O2− and OH− ions (in the molar proportion O2−/OH− of 2/1). On either side of this middle layer there are two-dimensional lattices of tetrahedrons, of which one of the vertices is occupied by an oxygen of the octahedral layer, while the other three are occupied by substantially coplanar oxygens. In natural smectites, for example, the tetrahedral sites are generally occupied by Si4+ or Al3+ ions, and the octahedral sites are in mosts cases occupied by Mg2+, Fe2+, Al3+ and/or Fe3+ cations. A small proportion of the octahedral and/or tetrahedral sites of the smectites is not occupied and is responsible for the cation deficit of the crystalline lattice forming the elementary lamellae.
Some phyllosilicates, such as smectites, are also characterized by the presence, between the elementary lamellae, of interfoliar spaces which contain water and cations and which form a swelling phase of the mineral. The smectites are therefore described as being of the swelling T.O.T. type. In natural smectites, these interfoliar cations are generally Mg2+, Ca2+ and/or Na+ ions.
Phyllosilicate mineral particles, such as talc, are used in the form of fine particles in many industrial sectors, for example: rubber, thermoplastics, paper, paints, pharmacy, cosmetics or also phytosanitary products. They are used as an inert filler (for their chemical stability or for the dilution of expensive active compounds) or as functional fillers (for example to enhance the mechanical properties of some materials).
WO 2008/009800 proposes a method for preparing 2:1 phyllogermanosilicate-swelling phyllogermanosilicate (T.O.T.-swelling T.O.T.) interlayer compositions which can be used especially as a precursor for the preparation of talcose compositions, in particular synthetic talc. These T.O.T.-swelling T.O.T. interlayer compositions are synthesized by precipitation of a gel containing silicon and/or germanium and metal followed by a hydrothermal treatment of the gel at a temperature of from 150° to 300° C. The parameters used for carrying out the method for preparing these compositions allow some of the structural characteristics of the synthesized mineral particles to be controlled, in particular the crystallinity and the swelling mineral phase/non-swelling mineral phase ratio.
The synthesized T.O.T.-swelling T.O.T. interlayer particles described in WO 2008/009800 can have different colors depending on the metal salt used in the starting gel containing silicon and/or germanium and metal.
However, obtaining T.O.T.-swelling T.O.T. interlayer particles according to WO 2008/009800 requires that the protocol for synthesizing these particles be carried out in its entirety for each color desired, and that the synthesis parameters be changed for each product of a different color that is desired. Furthermore, once the T.O.T.-swelling T.O.T. interlayer particles have been synthesized, their color cannot be modified, the color being determined by the choice of reagents used in the first step of precipitation of the gel containing silicon and/or germanium and metal. Moreover, the choice of colors which can thus be obtained according to WO 2008/009800 remains limited, it being limited by the starting divalent metal salts which can be used.
In addition, although some natural talcs (steatites) exhibit varied colors such as pink, grey or green when they are in the form of blocks as obtained directly after extraction, grinding thereof into fine particles irretrievably leads to the obtaining of powders which are white to greyish in color, the color of the natural talc being due solely to the particular arrangement of the talc particles relative to one another. The grinding of such natural talcs therefore leads irretrievably to a loss of the possibly pink or greenish original natural color of the talc.

Method for preparing a composition comprising coloured silicate mineral particles and a composition comprising coloured silicate mineral particles

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE (C.N.R.S.)


An automated vehicle dispatch and payment honoring system which is comprised of a computerized system with specialized software which enables a user to select a particular Taxi or vehicular transport company from a menu, along with the desired destination and number of passengers traveling. The software provides multi-lingual, user-friendly menu driven choices, which might include advertising for restaurants, hotels, etc. The system then displays the approximate fare and provides alternative forms of payment which are honored by that particular transport company. This system might include individualized computerized stands or wall unit strategically positioned in such crowded places as airports, hotels, and banks. Such stands could electronically receive and scan credit or debit cards. The software system might also be accessed via computer or telephonic link. The finalized request for service is relayed to a dispatcher via telecommunication, satellite, or computer link. The dispatcher can then route the appropriate vehicle to the requesters location whereby a pre-printed credit voucher, as verified and generated by the system could be exchanged for the transportation services rendered.

It is known in the prior art to transmit requests for services for a multiplicity of remote call boxes by radio channel transmission, transmitting alarms, encoding signals and for summoning emergency services to a central dispatch location. Such prior art systems may transfer messages unidirectional or bidirectional, by radio channel or in digital form. However, they are generally unitary systems which can serve only one company. This invention differentiates itself from the prior art by offering a host computerized vehicle stand unit designed to serve numerous companies and honor payment of services by credit card or by a host card, i.e. a TAXILINK CARD as shown in FIG. 1B. The example Taxilink card offers corporate customers a direct billing option for payment of services rendered within a billing cycle. Personal customers can also use the prepaid Taxilink Card to pay for services. The present invention, among other aspects, further differentiates itself from the prior art by providing for transmission of the request for services and payment of services through a telecommunication and satellite link.
The prior art which primarily uses single communication channel or a digital signals is also strictly limited to one language for entering request for services. The present invention offers the user menu-type options including many foreign languages along with a better means to assist and inform the user on selecting a destination and payment option before making a request for service. Each system unit operates independent and therefore is unaffected by its geographical relationship to one another.
As an example of the prior art, U.S. Pat. No. 4,928,099 for a TELEMETRY SYSTEM FOR AUTOMATED REMOTE CALLING AND CENTRAL DISPATCH OF SERVICES, PARTICULARLY TAXICABS, discloses a telemetry system distributed geographically via call boxes which synchronously transmits digital taxicab requests. Each call box repeats its transmission at intervals to insure non-conflicting receipt of the message. A central computer receives and processes the messages to eliminate redundancy, display requests to a dispatcher service, and log all requests and responses thereto. The call box can also send messages regarding vandalism, low power, and/or the system's general on-line status.
U.S. Pat. No. 5,168,451 for a USER RESPONSIVE TRANSIT SYSTEM discloses a user responsive transit system which includes a number of service request terminals located at intervals in areas served by the transit system. Passengers use the service request terminals to transmit a request to a central dispatch controller, the controller receives the request and automatically dispatches the most efficient vehicle by calculating the total travel distance in relation to previously assigned dispatches. A service request is dispatched to the particular vehicle which would have the minimum added travel distance. A geographical display map of the area with the various dispatch requests can be provided for viewing the vehicle operator. The vehicle operator can thereby determine the most efficient route to service the dispatch requests.
Accordingly, what is needed in the field is a computerized vehicle summoning stand or unit which functions independently from other units and can send request information to any of a variety of companies. The unit would contain specialized software which prompts the user for such information including the language desired for the transaction, the number of passengers, destination, and the type of vehicle desired. The approximate fare could then be calculated and displayed and the unit would be capable of receiving and processing payment of the fare, with a voucher being issued to the user. The free-standing unit might similarly be incorporated into a wall unit or existing computerized access system, with a telecommunication, computerized or satellite link being used to convey the vehicle request and payment information.

Automated vehicle dispatch and payment honoring system


A malware scanner (8) operates to scan compressed computer files (16) by compressing the malware signatures (17) using the same compression algorithm as used for the compressed computer file and then comparing the compressed malware signatures (18) with the compressed computer file directly.

1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to scanning for malware, such as, for example, computer viruses, Trojans, worms, banned files and banned words within e-mail messages.
2. Description of the Prior Art
It is known to provide malware scanners that operate using a library of malware signatures each comprising a plurality of characteristics identifying a particular piece of malware. The scanner searches within a computer file to be scanned to see if it contains data matching the signatures. This is a relatively efficient and effective methodology.
A problem arises when scanning compressed computer files. The compression performed upon such computer files alters the data values making up the computer file such that characteristics indicative of a computer virus will be altered by the compression process into a form in which they will not match the virus signatures within the library. In order to deal with this, the known approach is to decompress the computer file to be scanned into an uncompressed form before searching that uncompressed form of the computer file for the presence of computer viruses using the virus signatures. Whilst this avoids the disguising of computer viruses by the compression applied, it has the disadvantage of consuming a significant amount of processing resources, in terms of both processing cycles and memory, in decompressing the computer file to be scanned. By their very nature, computer files that have been compressed tend to be disadvantageously large when decompressed.

This patent is subject to a terminal disclaimer.

Malware scanning of compressed computer files


Cooperative embedded agents as well as manageability and security operations that can be performed on a host system having cooperative embedded agents are disclosed.

Since the 386SL processor was introduced by the Intel Corporation, System Management Mode (SMM) has been available on 32-bit Intel Architecture (IA32) processors as an operation mode hidden to operating systems that executes code loaded by the basic input/output system (BIOS) or firmware. The mode is deemed "hidden" because SMM operations occur independently of the operating system (OS) and software applications.
IA32 processors are enabled to enter SMM via activation of a System Management Interrupt (SMI) signal. A similar signal called the Processor Management Interrupt (PMI) signal that is roughly analogous to the SMI signal is used for Itanium™-class processors, also available from Intel Corporation. For simplicity, both SMI and PMI signals can be referred to as xMI.
To date, most BIOS implementations that leverage the SMM capability simply register a monolithic section of code that is created during the build of the BIOS to support a specific function or set of functions particular to systems that use the BIOS. There is no provision in today's systems for the registration or execution of third-party SMM code, thus allowing no extensibility to the SMM framework. Such extensibility is often desired. For example, if the functions provided by the SMM code provided by the original equipment manufacturer (OEM) or the BIOS vendor for a given platform is insufficient, a developer or value-added reseller (VAR) has to either license the existing code from the BIOS vendor or OEM and attempt to graft their own logic into their implementation of SMM code.
In addition, today's implementations on IA32 processors are restricted to the 16-bit mode of the processor, thus limiting the size of the code and the possible leveraging of 32-bit or 64-bit software engineering techniques. In general, BIOS updates for SMM functions are problematic to effect and because the OS already has a hardware extensibility mechanism via its own driver model, BIOS vendors and OEMs are less motivated to provide these types of BIOS updates.


An endotracheal tube includes a main tubular portion including a distal end and a proximal end opposite the distal end, the main tubular portion including a central lumen at least in part defined by a wall of the main tubular portion; a wire lumen disposed within the wall of the main tubular portion, the wire lumen defined at least in part by a sidewall portion of the wire lumen and extending from about the proximal end of the main tubular portion to about the distal end of the main tubular portion; a wire disposed in the wire lumen; and one or more cutouts extending along a portion of the wall of the main tubular portion, the cutouts comprising openings in the sidewall portion of the wire lumen, wherein the cutouts are not in fluid communication with the central lumen.

Endotracheal intubation can be one of the most critical and life-saving procedures performed in the pre-hospital and emergency room settings. The few critical minutes spent during endotracheal tube placement can be very chaotic and stressful.
Prior procedure for placing an endotracheal tube requires the intubating provider to gather and open a minimum of three pieces of equipment: an endotracheal tube, a stylet, and a syringe to inflate a cuff proximate the distal end of the endotracheal tube. Also required is the use of a device to visualize the vocal chords. Further, a chest x-ray also typically is performed—with a radiologist reading the x-ray—to confirm the placement of the endotracheal tube. Such prior procedure is both cumbersome and costly.
For example, the stylet is a stiff wire that is inserted into the lumen of the endotracheal tube. The stylet is placed to give the endotracheal tube the stiffness required so that the tube can be pushed through the oral, or nasopharyngeal cavity, and through the vocal cords. Typically, the intubating provider is required to bend the stylet into a desired shape. Often the intubating provider manipulates the patient to obtain a direct view of the vocal cords using a laryngoscope. Video enabled intubation devices do not require as much manipulation of the patient. The stylet shape can vary from a hockey stick shape used when direct visualization of the vocal cords are used, or a more acute and curved shape when video devices are used. Thus, depending on the intubating device used, the provider may need different shapes stylets, or one that can take on different shapes.
Thus, there remains a need for an improved endotracheal tube system and method.


A data communication system includes circuitry to assure components respond to variations in the time length of the valid data window or “eye” of the high speed data communication signal. A self-test portion of the system periodically injects the effects of phase jitter into the data communication signal to assure the system performs properly.

1. Technical Field
The present invention relates to high speed data communication systems having self-test features. More specifically, the present invention provides a communication system with the capability to periodically assure proper performance and receipt of data during variations in the time length of the data window or "eye" of signals in the communication system.
2. Description of the Related Art
In high speed data communication systems, particularly those over a fiberoptic cable, it is desirable both during assembly and installation of the components, as well as periodically during service thereafter, to test these systems and verify proper receipt and performance of data in the system. The term "eye" is a well known communications term used to define the valid data window available to the circuitry that is expected to receive the signal from the cable.
An example of an eye or signal window in ideal form is depicted in a set of eyes 10 occurring repeatedly as a function of time in a signal waveform 12 in FIG. 1. In FIG. 2, an eye 14 is depicted as a function of time of the type representing an example of a signal window actually present in a received waveform 16. Areas 18 and 20 preceding and following the eye 14 represent the effect of noise and other factors which can be present in signals typically present in data transmission network. It can be seen that the waveform time duration of the eye 14 is considerably less than the bit time of the ideal time window or eye 10 in FIG. 1. This is caused by many things that affect the time delay of an actual signal from one end to the other end of the data transmission system.
Jitter is a commonly used term to refer to the time variation between the transmitted bits. Jitter is measured for high speed data transmission in time intervals such as pico seconds (1 pico second=10−9 sec.). If the jitter is too great from one transmitted bit to another transmitted bit, the eye becomes so short as to in effect cease to exist. Data transmission is not then possible either in the equipment under test or over an installed network. It is important to evaluate the response of communication networks and equipment to the effects of jitter. It would thus be desirable to be able to test high speed communication systems, both during assembly and installation and also during subsequent service, to determine the ability of a system and its components to respond to fluctuations or changes in the time length of the data window or "eye" of signals.

Data communication system with self-test feature

International Business Machines Corporation


Given a set of elliptic curve points defined over a field F(p) and represented in projective coordinate, a method is presented which allows the embedding of data bits in both the X-coordinate and the Z-coordinate of the elliptic curve point when represented in projective coordinate. This makes the number of points that satisfy an elliptic curve equation and which can be used in the corresponding cryptosystem proportional to p2 rather than p. This can be used to either increase security by making the bit positions where data bits are embedded known only to the sender and receiver. Alternatively, it can be used to increase the number of data bits that can be encrypted per single elliptic curve point encryption. In another alternative, it can also be used to reduce p. Also, it can be used as a countermeasure by randomizing the bit positions where data bits are embedded. A similar formulation can be developed for elliptic curves over fields F(2m), as well as special elliptic curves such as Montgomery curves.

Cryptography provides methods of providing privacy and authenticity for remote communications and data storage. Privacy is achieved by encryption of data, usually using the techniques of symmetric cryptography (so called because the same mathematical key is used to encrypt and decrypt the data). Authenticity is achieved by the functions of user identification, data integrity, and message non-repudiation. These are best achieved via asymmetric (or public-key) cryptography.
In particular, public-key cryptography enables encrypted communication between users that have not previously established a shared secret key between them. This is most often done using a combination of symmetric and asymmetric cryptography: public-key techniques are used to establish user identity and a common symmetric.key, and a symmetric encryption algorithm is used for the encryption and decryption of the actual messages. The former operation is called key agreement. Prior establishment is necessary in symmetric cryptography, which uses algorithms for which the same key is used to encrypt and decrypt a message. Public-key cryptography, in contrast, is based on key pairs. A key pair consists of a private key and a public key. As the names imply, the private key is kept private by its owner, while the public key is made public (and typically associated to its owner in an authenticated manner). In asymmetric encryption, the encryption step is performed using the public key, and decryption using the private key. Thus the encrypted message can be sent along an insecure channel with the assurance that only the intended recipient can decrypt it.
The key agreement can be interactive (e.g., for encrypting a telephone conversation) or non-interactive (e.g., for electronic mail).
User identification is most easily achieved using what are called identification protocols. A related technique, that of digital signatures, provides data integrity and message non-repudiation in addition to user identification.
The public key is used for encryption or signature verification of a given message, and the private key is used for decryption or signature generation of the given message.
The use of cryptographic key pairs was disclosed in U.S. Pat. No. 4,200,770, entitled "CRYPTOGRAPHIC APPARATUS AND METHOD." U.S. Pat. No. 4,200,770 also disclosed the application of key pairs to the problem of key agreement over an insecure communication channel. The algorithms specified in this U.S. Pat. No. 4,200,770 relies for their security on the difficulty of the mathematical problem of finding a discrete logarithm. U.S. Pat. No. 4,200,770 is hereby incorporated herein its entirety by reference.
In order to undermine the security of a discrete-logarithm based crypto algorithm, an adversary must be able to perform the inverse of modular exponentiation (i.e., a discrete logarithm). There are mathematical methods for finding a discrete logarithm (e.g., the Number Field Sieve), but these algorithms cannot be done in any reasonable time using sophisticated computers if certain conditions are met in the specification of the crypto algorithm.
In particular, it is necessary that the numbers involved be large enough. The larger the numbers used, the more time and computing power is required to find the discrete logarithm and break the cryptograph. On the other hand, very large numbers lead to very long public keys and transmissions of cryptographic data. The use of very large numbers also requires large amounts of time and computational power in order to perform the crypto algorithm. Thus, cryptographers are always looking for ways to minimize the size of the numbers involved, and the time and power required, in performing the encryption and/or authentication algorithms. The payoff for finding such a method is that cryptography can be done faster, cheaper, and in devices that do not have large amounts of computational power (e.g., hand-held smart-cards).
A discrete-logarithm based crypto algorithm can be performed in any mathematical setting in which certain algebraic rules hold true. In mathematical language, the setting must be a finite cyclic group. The choice of the group is critical in a cryptographic system. The discrete logarithm problem may be more difficult in one group than in another for which the numbers are of comparable size. The more difficult the discrete logarithm problem, the smaller the numbers that are required to implement the crypto algorithm. Working with smaller numbers is easier and faster than working with larger numbers. Using small numbers allows the cryptographic system to be higher performing (i.e., faster) and requires less storage. So, by choosing the right kind of group, a user may be able to work with smaller numbers, make a faster cryptographic system, and get the same, or better, cryptographic strength than from another cryptographic system that uses larger numbers.
1.1 Elliptic Curves & Cryptography
The groups referred to above come from a setting called finite fields. Methods of adapting discrete-logarithm based algorithms to the setting of elliptic curves are known. However, finding discrete logarithms in this kind of group is particularly difficult. Thus elliptic curve-based crypto algorithms can be implemented using much smaller numbers than in a finite-field setting of comparable cryptographic strength. Thus the use of elliptic curve cryptography is an improvement over finite-field based public-key cryptography.
In practice, an Elliptic Curve group over Fields F(p) is formed by choosing a pair of a and b coefficients, which are elements within F(p). The group consists of a finite set of points P(x,y) which satisfy the elliptic curve equationF(x,y)=y2−X3−ax−b=0   1.1
together with a point at infinity, O. The coordinates of the point, x and y, are elements of F(p) represented in N-bit strings. In what follows, a point is either written as a capital letter, e.g. P, or as a pair in terms of the affine coordinates, i.e. (x,y).
The Elliptic Curve Cryptosystem relies upon the difficulty of the Elliptic Curve Discrete Logarithm Problem (ECDLP) to provide its effectiveness as a cryptosystem. Using multiplicative notation, the problem can be described as: given points B and Q in the group, find a number k such that Bk=Q; where k is called the discrete logarithm of Q to the base B. Using additive notation, the problem becomes: given two points B and Q in the group, find a number k such that kB=Q.
In an Elliptic Curve Cryptosystem, the large integer k is kept private and is often referred to as the secret key. The point Q together with the base point B are made public and are referred to as the public key. The security of the system, thus, relies upon the difficulty of deriving the secret k, knowing the public points B and Q. The main factor that determines the security strength of such a system is the size of its underlying finite field. In a real cryptographic application, the underlying field is made so large that it is computationally infeasible to determine k in a straightforward way by computing all the multiples of B until Q is found.
The core of the elliptic curve geometric arithmetic is an operation called scalar multiplication which computes kB by adding together k copies of the point B. The scalar multiplication is performed through a combination of point-doubling and point-addition operations. The point-addition operation adds two distinct points together and the point-doubling operation adds two copies of a point together. To compute, for example, 11 B=(2*(2*(2B)))+2B=Q, it would take 3 point-doublings and 2 point-additions.
Addition of two points on an elliptic curve is calculated as follows. When a straight line is drawn through the two points, the straight line intersects the elliptic curve at a third point. The point symmetric to this third intersecting point with respect to the x-axis is defined as a point resulting from the addition.
Doubling a point on an elliptic curve is calculated as follows. When a tangent line is drawn at a point on an elliptic curve, the tangent line intersects the elliptic curve at another point. The point symmetric to this intersecting point with respect to the x-axis is defined as a point resulting from the doubling.
Table 1 illustrates the addition rules for adding two points (x1, y1) and (x2, y2) that is,(x3, y3)=(x1, y1)+(x2, y2)  1.2
TABLE 1Summary of Addition Rules:(x3, y3) = (x1, y1) + (x2, y2)General Equations                                          x            3                    =                                                    m                .                            2                        -                          x              2                        -                          x              1                                                                                y            3                    =                                    m                                                                                (                                                      x                    3                                    -                                      x                    1                                                  )                                      +                          y              1                                              Point Addition  m  =                    y        2            -              y        1                            x        2            -              y        1             Point Doubling (x3, y3) = 2(x1, y1)  m  =                    3                          x          1          2                    -      a              2                    y        1             (x2, y2) = −(x1,y1)(x3, y3) = (x1, y1) + (−(x2, y2)) = O(x2, y2) = O(x3, y3) = (x1, y1) + O = (x1, y1)−(x1, y2)=(x1, −y1)1.2 Overview of Elliptic Curve Encryption and DecryptionGiven a message point (xm, ym), a base point (xB, yB), and a given key, k, the cipher point (xc, yc) is obtained using the following equation,(xc, yc)=(xm, ym)+k(xB, yB)  1.3There are two basics steps in the computation of the above equations. The first is to find the scalar multiplication of the base point with the key, "k(xB, yB)". The resulting point is then added to the message point, (xm, ym) to obtain the cipher point.At the receiver, the message point is recovered from the cipher point which is usually transmitted, the shared key and the base point, that is(xm, ym)=(xc, yc)−k(xB, yB)  1.41.3 Embedding Message Data on Elliptic Curve Points
As indicated earlier, the x-coordinate, xm, is represented as an N-bit string. Not all of the N-bits are used to carry information about the data of the secret message.
Assuming that the number of bits of the x-coordinate, xm, that do not carry data is L. The extra bits, L, are used to ensure that message data when embedded into the x-coordinate will lead to an xm value that satisfies the elliptic curve equation, equation 1.1. Usually, if the first guess of xm is not on a curve, then the second or third try is. This was first proposed in "N. Kobltiz, Introduction to Elliptic Curve and Modular Forms, New York: Springer-Verlag 1993".
Therefore the number of bits used to carry the bits of the message data is (N−L). Assuming that the secret data is an M-bit string. The number of elliptic curve points needed to encrypt the K-bit data is
      ⌈          K              N        -        L              ⌉    .
It is important to note that the y-coordinate, ym, of the message point carries no data bits.
1.4 Attacks
The difficulty in solving the elliptic curve discrete logarithm problem has been established theoretically while information associated with secret information such as the private key or the like may leak out in cryptographic processing in real mounting. Thus, there has been proposed an attack method of so-called power analysis in which the secret information is decrypted on the basis of the leak information.
An attack method in which change in voltage is measured in cryptographic processing using secret information such as DES (Data Encryption Standard) or the like, so that the process of the cryptographic processing is obtained and the secret information is inferred on the basis of the obtained process is disclosed in P. Kocher, J. Jaffe and B. Jun Differential Power Analysis, Advances in Cryptology: Proceedings of CRYPTO '99, LNCS 1666, Springer-Verlag, (1999) pp. 388-397. This attack method is called DPA (Differential Power Analysis).
An elliptic curve cryptosystem to which the above-mentioned attack method is applied is disclosed in J. Coron, Resistance against Differential Power Analysis for Elliptic Curve Cryptosystems, Cryptographic Hardware and Embedded Systems: Proceedings of CHES '99, LNCS 1717, Springer-Verlag, (1999) pp. 292-302. In the elliptic curve cryptosystem, encryption, decryption, signature generation and signature verification of a given message have to be carried out with elliptic curve operations. Particularly, calculation of scalar multiplication on an elliptic curve is used in cryptographic processing using a scalar value as secret information.
As one of the measures against DPA attack on elliptic curve cryptosystems, a method using randomized projective coordinates is known. This is a measure against an attack method of observing whether a specific value appears or not in scalar multiplication calculation, and inferring a scalar value from the observing result. That is, by multiplication with a random value, the appearance of such a specific value is prevented from being inferred.
In the above-mentioned background-art elliptic curve cryptosystem, attack by power analysis such as DPA or the like was not taken into consideration. Therefore, to relieve the attack by power analysis, extra calculation, or the like, other than necessary calculation had to be carried out in cryptographic processing using secret information so as to weaken the dependence of the process of the cryptographic processing and the secret information on each other. Thus, time required for the cryptographic processing increased so that cryptographic processing efficiency was lowered conspicuously in a computer such as an IC card, or the like, which was slow in calculation speed, a server managing an enormous number of cryptographic processes, or the like. In addition, the dependence of cryptographic processing process and secret information on each other cannot be cut off perfectly. In addition, if priority was given to the cryptographic processing efficiency, the cryptosystem was apt to come under attack by power analysis so that there was a possibility that secret information leaks out
1.5 Speed of Computations
With the development of information communication networks, cryptographic techniques have been indispensable elements for concealment or authentication about electronic information. Speeding up is demanded along with the security of the cryptographic techniques. The elliptic curve discrete logarithm problem is so difficult that elliptic curve cryptosystems can make key length shorter than that in RSA (Rivest-Shamir-Adleman) cryptosystems basing their security on the difficulty of factorization into prime factors. Thus, the elliptic curve cryptosystems open the way to comparatively high-speed cryptographic processing. However, the processing speed is not always high enough to satisfy smart cards which have restricted throughput or servers which have to carry out large volumes of cryptographic processing. It is therefore demanded to further speed up the processing in cryptosystems.
The two equations for m in Table 1 are called slope equations. Computation of a slope equation in integer fields requires one modular integer division. Alternatively, the slope computation can be computed using one modular integer inversion and one modular integer multiplication. Modular integer division and modular integer inversion are expensive computationally because they require extensive CPU cycles for the manipulation of two large integers modular a large prime number. Today, it is commonly accepted that a point-doubling and point-addition operation each requires one inversion, two multiplies, a square, and several additions. To date there are techniques to compute modular integer division and modular integer inversion, and techniques to trade expensive inversions for multiplies by performing the operations in projective coordinates.
In cases where field inversions are significantly more expensive than multiplication, it is efficient to implement projective coordinates. An elliptic curve projective point (X,Y,Z) in conventional projective (or homogeneous) coordinates satisfies the homogeneous Weierstrass equation,{tilde over (F)}(X,Y,Z)=Y2Z−X3−aXZ2−bZ3=0  1.5
and, when Z≠0, it corresponds to the affine point
      (          x      ,      y        )    =            (                        X          Z                ,                  Y          Z                    )        .  It turns out that other projective representations lead to more efficient implementations of the group operation [D. V. Chudnovsky and G. V. Chudnovsky, Sequences of numbers generated by addition in formal groups and new primality and factorization tests, Adv. In Appli. Math. Vol. 7, 1987, pp 385-434.]. In particular, the Jacobian representations where the triplets (X,Y,Z) corresponds to the affine coordinates
      (          x      ,      y        )    =      (                  X                  Z          2                    ,              Y                  Z          3                      )  whenever Z≠0. This is equivalent to using Jacobian elliptic curve equation that is of the form,{tilde over (F)}j(X,Y,Z)=y2−X3−aXZ4−bZ6=0  1.6
Another commonly used projection is the Chudnovsky-Jacobian coordinates.
In general terms, the relationship between the affine coordinates and the projection coordinates can be written as
      (          x      ,      y        )    =      (                  X                  Z          i                    ,              Y                  Z          j                      )  where the values of i and j depend on the choice of the projective coordinates. For example for homogeneous coordinates, i=1 and j=1.
It is important to note that the group addition rules are defined in the affine coordinates and not in any of the projective coordinates, that is,
                              (                                                    X                3                                            Z                3                i                                      ,                                          Y                3                                            Z                3                j                                              )                =                              (                                                            X                  1                                                  Z                  1                  i                                            ,                                                Y                  1                                                  Z                  1                  j                                                      )                    +                      (                                                            X                  2                                                  Z                  2                  i                                            ,                                                Y                  2                                                  Z                  2                  j                                                      )                                      1.7
In other words, the computation of the coordinate values of X3, Y3 and Z3 are based on the equations in Table 1, whereby the value of Z3 is chosen from the denominator of the equations in Table 1 in order to remove the division operations from the calculations of X3 and Y3
This implies that
      (                            X          1                          Z          1          i                    ,                        Y          1                          Z          1          j                      )    ,            (                                    X            2                                Z            2            i                          ,                              Y            2                                Z            2            j                              )                              and                                (                                    X            3                                Z            3            i                          ,                  -                                    Y              3                                      Z              3              j                                          )      lie on the same straight line, while (X1, Y1, Z1), (X2, Y2, Z2) and (X3, −Y3, Z3) do not lie on the same line.
This implies that one cannot write,(X3, Y3, Z3)=(X1, Y1, Z1)+(X2, Y2, Z2)
when the addition, +, is defined over the affine coordinate.
It should be noted that defining the elliptic curve points as a group over addition is necessary so that equation 1.7 can be re-written as,
      (                            X          2                          Z          2          i                    ,                        Y          2                          Z          2          j                      )    =            (                                    X            3                                Z            3            j                          ,                              Y            3                                Z            3            j                              )        -          (                                    X            1                                Z            1            i                          ,                              Y            1                                Z            1            j                              )
It is this group definition, which leads to the fact that decryption, which is described in equation 1.4, is in fact the reciprocal of encryption as defined in equation 1.3.
The use of projective coordinates circumvents the need for division in the computation of each point addition and point doubling during the calculation of scalar multiplication. Therefore, integer modular division can be avoided in the calculation of
scalar multiplication,
  k        (                            X          B                          Z          B          i                    ,                        Y          B                          Z          B          j                      )  when using projective coordinate.
The last addition for the computation of the cipher point,
      (                            X          C                          Z          C          i                    ,                        Y          C                          Z          C          j                      )    ,i.e. the addition of the two points
      (                            X          m                          Z          m          i                    ,                        Y          m                          Z          m          j                      )                and                  k              (                                    X            B                                Z            B            i                          ,                              Y            B                                Z            B            j                              )      can also be carried out in the chosen projection coordinate, that is
      (                            X          C                          Z          C          i                    ,                        Y          C                          Z          C          j                      )    =            (                                    X            m                                Z            m            i                          ,                              Y            m1                                Z            m            j                              )        +          (                                    X            B                                Z            B            i                          ,                              Y            B                                Z            B            j                              )
It should be pointed out that Zm=1.
However, one division (or one inversion and one multiplication) must still be carried out to calculate
            x      C        =                  X        C                    Z        C        i              ,since only the affine x-coordinate of the cipher point, xC, is sent by the sender.
Therefore the encryption of (N−L) bits of the secret message using elliptic curve encryption requires at least one division when using projective coordinates. Similarly, the decryption of a single message encrypted using elliptic curve cryptography also requires at least one division when using projective coordinates.
The state of elliptic curve cryptography is described in a paper by Neal Koblitz, Alfred Meneges and Scott Vanstone, Design, Codes and Cryptography 19 173-193 (2000) which is incorporated herein in its entirety by reference. More recent developments are described in the Vanstone et al. U.S. Pat. No. 6,424,712 and the published patent applications U.S. 2003/0059042 of Okeya et al., number 2003/0123656 of Izu et al. and 2003/0142820 of Futa et al. all of which are incorporated herein by reference. An earlier Pat. No. 4,200,770 of Hellman et al. discloses an earlier cryptographic apparatus and method and is also incorporated herein by reference.
The 0059042, 0123656 and 0142820 patent applications and U.S. application Ser. No. 6,424,712 address the issue of speeding up elliptic curve scale multiplications.

Method for XZ-elliptic curve cryptography

King Fahd University of Petroleum and Minerals


Provided is a method and apparatus for controlling an event of a cable modem and reporting a status of the cable modem, the method including: determining whether to periodically allocate a transmission bandwidth of a CM-STATUS message with respect to an event occurrence of the cable modem; setting an event control encoding that includes information regarding whether to periodically allocate the transmission bandwidth; and generating a MAC Domain Descriptor (MDD) message containing the event control encoding to transmit the generated MDD message.

1. Field of the Invention
The present invention relates to a method and apparatus for controlling an event of a cable modem and reporting a status of the cable modem. More particularly, the present invention relates to a method and apparatus for controlling an event of a cable modem and reporting a status of the cable modem that may request a transmission bandwidth of a CM-STATUS message using a periodically allocated polling interval as well as a contention interval, when a mode allocated for the transmission bandwidth of the CM-STATUS message is determined as the polling mode.
2. Description of the Related Art
A cable modem termination system (CMTS) and a cable modem according to a Data Over Cable Service Interface Specification (DOCSIS) 3.0 standard adopt a channel combination scheme that may transmit data via a plurality of upstream channels and downstream channels.
The cable modem capable of simultaneously transmitting and receiving data via the plurality of upstream channels and downstream channels may periodically receive a MAC Domain Descriptor (MDD) message via all the downstream channels included in a Media Access Control (MAC) domain. Here, the MDD message transmitted via a primary channel may include a set of available upstream channels and downstream channels that the cable modem may use, and control and setting information associated with the MAC domain. For example, the MDD message may include parameters associated with a CM-STATUS message reporting mechanism that is used after registration of the cable modem. When an event occurs, the cable modem may transmit the CM-STATUS message to the CMTS to thereby inform the CMTS about the occurrence of the event. The MDD message periodically transmitted by the CMTS may include information regarding an event type code that may need to be reported using the CM-STATUS message, a holdoff timer indicating when to transmit the CM_STATUS message, a maximum number of transmittable reportings, and the like.
When an event control encoding associated with the CM-STATUS message is not included in the MDD message transmitted via the primary channel, the cable modem may not transmit the CM-STATUS message to the CMTS although the event occurs.
The CMTS may control reporting about the event of the cable modem, or may instruct the cable modem to take an appropriate action for the occurrence of the event, using a CM-CTRL message. For example, the CMTS may transmit enable bistmask information associated with each of events of CM-STATUS and thereby control whether to report a corresponding event.
FIG. 1 illustrates a format of a CM-STATUS message according to a conventional art.
Referring to FIG. 1, the CM-STATUS message may include a transaction identification (ID) 102 and an event type 103 indicating which event occurs, and type/length/value (TLV) encoded information associated with a corresponding event, behind a MAC management message header 101. FIG. 2 is a table illustrating types of events reported by a cable modem using the CM-STATUS message.
In the case of the events as shown in FIG. 2, when corresponding objects are enabled, the cable modem may report the occurrence of a corresponding event to a CMTS using the CM-STATUS message. Parameters associated with an event type may include a downstream channel identifier (ID), an upstream channel ID, a Downstream Service ID (DSID), and the like.
Since the cable modem remembers that each of the events is in an "on" status or an "off" status, the cable modem may report to the CMTS about a situation where a corresponding event triggers the "on" status, or resets to the "off" status. Reporting of the event status may use a maximum holdoff timer value and a maximum report count value that are obtained from an MDD message. Here, the maximum holdoff timer denotes a point in time for transmitting the CM-STATUS message, and the maximum report count denotes a parameter about a number of transmissions.
In a Hybrid Fiber Coax (HFC) network, in the case of an upstream transmission, a plurality of cable modems may access a single CMTS to share an upstream bandwidth. Therefore, the CMTS may designate a particular cable modem, among the plurality of cable modems, to perform an upstream transmission. Specifically, a cable modem may request the CMTS for a bandwidth allocation. When the cable modem is assigned with an opportunity for the upstream transmission, the cable modem may have an opportunity to transmit a message to the CMTS. When an event occurs whereby the cable modem desires to transmit the CM-STATUS message, the cable modem may need to request the CMTS for a bandwidth allocation in order to transmit the message.
FIG. 3 illustrates a mechanism for transmitting a bandwidth allocation request message of a cable modem in a contention-based transmission interval according to the conventional art.
Referring to FIG. 3, when an event occurs in an interval 303, the cable modem may verify a contention transmission interval using a received upstream bandwidth allocation map 301, calculate a transmission opportunity using a backoff window value, and wait for the transmission opportunity by the backoff window value, and then transmit a bandwidth allocation request message 305. When the cable modem recognizes a collision 307 after the request, the cable modem may retransmit another bandwidth allocation request message 309 according to a Truncated Binary Exponential Backoff (TBEB) policy.
Here, the contention based transmission interval is allocated for only a particular cable modem. Thus, when a plurality of cable modems simultaneously performs a transmission, a collision may occur. When the collision occurs, the plurality of cable modems may need to increase a contention backoff window value and then perform a retransmission according to the TBEB policy, which results in a delay 311.
When an event that needs to transmit a CM-STATUS message occurs, a cable modem may transmit the CMTS message according to a bandwidth request using a contention scheme or a piggyback scheme. The piggyback scheme denotes a scheme that may simultaneously transmit data and request a bandwidth required for a header. Therefore, while the data is not being transmitted, reporting may need to be performed through the bandwidth request using the contention scheme. In this instance, when many cable modems access a network, or when an inter-network event occurs in a plurality of cable modems, a collision may occur in making the bandwidth request. In this case, reporting to the CMTS about the event occurrence of the cable modem may be delayed.
Accordingly, there is a need for a method that enables a cable modem to quickly and effectively report to a CMTS about a status of an event occurring in the cable modem, and enables the CMTS to quickly recognize the event occurrence of the cable modem.

Method for controlling event and reporting status of cable modem and apparatus thereof

Electronics and Telecommunications Research Institute


A system for cooling a structure or mechanism through transpiration processes. Generally a porous structural material may be used to form a hot wall surface of a high temperature or high heat flux environment component, typically used in combustion type devices. Coolant pressurized on the “cold” or cooler side of the wall is bled, “sweated”, or otherwise transpired to the “hot” wall surface in an effort to control the hot wall surface temperature by shielding the surface with a coolant layer at the surface and by removing heat via coolant flow past the surface. This may be done to manage the hot wall temperature for structural purposes, more effectively manage high heat fluxes, or to hide thermal signatures. The porous material can be selectively made such that the coolant material flows substantially in one direction only through the porous material to transfer thermal energy only away from the structure rather than towards the structure.

Many materials are known to be porous, generally being inherently porous. The naturally porous materials can be provided as filters or as transpiration coolers for various applications. Nevertheless, many natural materials include a porosity that is also substantially "natural". Simply, the natural porosity of many materials is highly variable. Although porosity for various materials may be within a generally known range, the porosity can be unevenly distributed throughout the material. Moreover, the natural porosity of a selected material may be within a large range rather than within a narrow porosity range. Furthermore, a material having a selected porosity may not include other selected or desirable characteristics, such as strength.
Nevertheless, it is desirable to provide materials that include a selected porosity, and more specifically a porosity that is substantially consistent throughout the material such that natural variations do not occur within the material. Therefore, the porosity will include a selected porosity and pore size. The entire material should have a known physical characteristic and capable of being applied in a substantially consistent manner.
Moreover, most often porous materials include a substantially multi-directional porosity. That is, the porosity is distributed such that flowable materials may move through the pores in both directions, from a first side to a second side and from the second side to the first side of the material. If the porous material is provided as a filter or membrane, a pressure differential across the membrane must be relied upon to move the material in a selected direction. Generally, this requires including additional manufacturing steps or structural elements in the final structure or device.
Therefore, it is also desirable to provide a material that is substantially directionally porous. Simply, a material that includes a porosity that allows material to flow in only one direction relative to the porous material. With a pressure differential supplied across the membrane, the pores of the membrane would allow a flow of material in only one direction. The flow may be dependent upon the material in which the pores are made or the material being flowed across the membrane; nevertheless, the membrane may be substantially uni-directional in its porosity for selected flowable materials.
It is also desired to provide many materials including selected porosities. That is, materials of various types including a selected porosity that include both a selected pore density, selected pore size, and selected directional porosity. Therefore, rather than providing only a single material including a selected porosity with a general technique, the materials could be varied and used in many different applications including different strengths and weight requirements that may be provided by various materials.
Also, it is known to cool various components, such as components of a rocket engine including turbine parts, combustion chambers, and nozzles. Cooling these systems in particularly harsh environments can be difficult due to the high heat flux, strength, and heat resistance needed of the various cooling components. Therefore, providing a cooling system in such an environment is often difficult, heavy, complex, or expensive. In addition, the cooling systems are generally large and bulky due to the requirements for heat transfer and strength in the environment. Therefore, it is also desirable to provide a cooling system that can easily cool a component in a harsh environment without great size or complexity.


A portable information-processing device with a color changing case includes a transparent case covering the device that contains a layer of color-changing electroluminescent film. When the electroluminescent film is subject to different potential level signals, the color of the film changes, so that the color of the case of the portable information-processing device may be altered as desired to increase the visual diversity of the product.

With the arrival of the information age, information-processing devices are widely used by the general public. The portable information-processing devices (such as notebook computers and the like) have a small size and are easy to carry, and are almost as powerful as the desktop computer, hence have been well received by users in recent years.
These days when consumers buy products they often consider many factors. Besides functional requirements, price and practicality, visual appealing also is an important consideration. The present exterior design of the portable information-processing devices mostly adopts a metal alloy (such as an aluminum magnesium alloy) case to improve the value perception. In addition to enhancing the case structural strength, it also aims to increase the appeal to consumers. The metal case often is colored in black or silver. Although it can enhance the product value perception, the limited exterior color selection becomes a constraint of product diversity.
On mobile communication devices (such as handsets), there are designs for replacing the cases. As the structure of the handset case is simple, users can replace the case of different colors as desired to rekindle their amusement without buying new handsets. Aside from increasing visual diversity of the product appearance, it provides rich choices for fashion-conscious consumers. However, on the portable information-processing devices, the structure of their cases is more complicated. Their cases generally are not designed for user DIY (Do-It-Yourself) disassembly or replacement. Hence how to make the exterior color of the portable information-processing device changeable to increase product visual diversity is an issue remaining to be resolved in the industry.

Portable information-processing device having a color changing case


A semiconductor device includes a plurality of bonding pads as bonding option, and a test circuit for performing an operation test using particular bonding pads and testing interconnects connecting internal circuits to the remaining bonding pads which are not used in the operation test.

1. Field of the Invention
The present invention relates to semiconductor devices, and in particular, relates to a semiconductor device having a plurality of bonding pads as bonding option and a test circuit, the bonding pads being connected to common internal circuits, the test circuit testing the states of interconnects between the bonding pads and the internal circuits, respectively.
2. Description of the Related Art
Recently, digital consumer devices have become smaller. Particularly, mobile devices are significantly reduced in size because a plurality of semiconductor chips are mounted on a single substrate of each device. For example, a plurality of chips, e.g., a CPU and memory devices such as a DRAM and a flash memory, are mounted on one substrate and are packaged with a resin, thus forming a single device component. Packaging technology includes various packaging designs, such as Multi-chip Package, System In Package, and Package On Package.
Packaging is principally performed in a factory of each device manufacturer. Therefore, the device manufacturer purchases semiconductor chips, such as CPUs and DRAMs, from individual semiconductor manufacturers. Each device manufacturer designs a device including the chips as compact as possible. Accordingly, the arrangement of bonding pads needed for each semiconductor chip varies from device manufacturer to device manufacturer, or from device to device. Consequently, each semiconductor manufacturer has to provide semiconductor chips with various bonding-pad arrangements in response to requests of the respective device manufacturers. For instance, a device manufacturer A requests DRAMs each having an array of pads on the left part of the chip and another device manufacturer B requests DRAMs each having an array of pads on the right part of the chip.
Under the above-described circumstances, the semiconductor manufacturers for the production of DRAMs have to produce chips with various pad arrangements for individual device manufacturers and deliver the chips to the respective manufacturers. Unfortunately, the production and delivery of the chips with various pad arrangements need time and money, leading to burdens on the semiconductor manufacturers. In consideration of the circumstances, the semiconductor manufacturers each provide the same semiconductor chips, e.g., DRAM chips each having a plurality of pads thereon in order to respond to all of requests of device manufacturers. Each device manufacturer selects any group of pads and performs a bonding process on the selected pads. Accordingly, the same DRAM chips can be delivered to the respective device manufacturers. Providing a plurality of pads, selecting necessary pads from the pads, and bonding the selected pads are called a bonding option technique.
However, since each chip includes a plurality of pads connected to common internal circuits, the semiconductor manufacturers have another problem related to an operation test. Before the shipment of chips to the respective device manufacturers as clients, each chip has to be subjected to an electrical characteristics test. If each chip includes pad groups as bonding option, any of the groups has to be selected for each client and be tested. Disadvantageously, selecting pads desired by the client from the pads, setting a probe card for bringing probes, corresponding to pads to be tested, into contact with the pads on the chip, and testing the pads also lead to a waste of time and money.
Accordingly, one group of pads are subjected to a test for DRAM, thus checking internal functions of each DRAM. In this case, other pads and interconnects are not checked. It is, therefore, necessary to test the unchecked pads and interconnects. It is preferred that unchecked pads is tested by simple, low-cost means without using a probe card.
Japanese Unexamined Patent Application Publication No. 2003-132698 discloses a test circuit for performing an operation test on semiconductor devices. In this test circuit, a plurality of memories are simultaneously subjected to the read operation to thereby detect a defective memory. The test circuit includes a current detection circuit and a fault-location identification circuit. The current detection circuit detects current flowing through an output driver of a memory connected to a tri-state bus. If a memory output includes an error, a shoot-through current flows. This shoot-through current is detected so as to identify a defective memory. For example, if an interconnect is disconnected, the disconnection cannot be detected because the test circuit detects different output levels. Unfortunately, this circuit cannot be applied to a test for interconnects connected to untested pads on a semiconductor device having a plurality of pads.
As described above, in a semiconductor device having a plurality of bonding pads connected to common internal circuits, some of the bonding pads and the corresponding interconnects are subjected to the operation test but the other pads and the associated interconnects in the vicinities thereof are untested. In the following description, a bonding pad and the associated interconnect in the vicinity thereof will be abbreviated to "pad interconnect". It is preferred to provide a method for readily testing unchecked pad interconnects without bring a probe card into contact with the unchecked pads.


A diagnostic apparatus for an exhaust gas purification apparatus including a selective catalytic reduction NOx catalyst (SCR catalyst) provided in an exhaust passage of an internal combustion engine, a supplying unit supplying ammonia or an ammonia precursor into exhaust gas flowing into the SCR catalyst and a sensor, provided on a downstream side of the SCR catalyst, detecting NOx and ammonia in exhaust gas. The diagnostic apparatus calculates an amount of decline in output of the sensor due to a reaction between NOx and ammonia at the sensor and performs a diagnosis of the supplying unit based on the calculated amount of decline in output of the sensor.

A selective catalytic reduction NOx catalyst (hereinafter, also simply referred to as a "NOx catalyst") is known which uses ammonia as a reducing agent to purify NOx (nitrogen oxides) contained in exhaust gas from an internal combustion engine. A supply apparatus for supplying ammonia or an ammonia precursor such as urea (hereinafter, also collectively referred to as a "reducing agent") into exhaust gas that flows into the NOx catalyst may be installed on an upstream side of the NOx catalyst in an exhaust passage. In order to cause NOx to be purified at a desired purification rate at the NOx catalyst, a supply amount of the reducing agent supplied from the supply apparatus must be controlled. A NOx sensor which is provided on a downstream side of the NOx catalyst and which is capable of detecting a concentration of NOx in exhaust gas is sometimes used for this control. Regarding the control of a supply apparatus, it is known that, when an output value from a NOx sensor follows a downward trend regardless of an increase in an amount of NOx flowing into a NOx catalyst, a determination is made that ammonia is flowing out from the NOx catalyst (an ammonia slip has occurred) due to an excessive supply amount of a reducing agent and, accordingly, an additive amount of urea water is reduced (for example, refer to PTL 1).
Accurate control of an amount of a reducing agent supplied from a supply apparatus requires the supply apparatus to be operating properly. Since a NOx sensor is capable of detecting ammonia in addition to NOx, an output value from a NOx sensor is known to be used to diagnose whether or not a supply apparatus is operating properly (in other words, whether the supply apparatus is in a normal state or an abnormal state) (for example, refer to PTL 2 through PTL 4). According to the techniques disclosed in these documents, during a diagnosis of a supply apparatus, a supply amount of a reducing agent from the supply apparatus is increased to a level where an output value of the NOx sensor is expected to exceed a prescribed threshold due to ammonia flowing out from the NOx catalyst. In addition, when an actual output value does not exceed the prescribed threshold, it is determined that the supply apparatus is not operating according to control and is in an abnormal state.

Diagnostic apparatus for exhaust gas purification apparatus


A blood washing device is employed for recovering shed blood or other sources of blood and preparing packed red cells therefrom. The device employs a gravity sedimentation procedure but achieves a shortened washing period by using an aggregating reagent for aggregating or agglomerating the red cells so as to increase their sedimentation velocity during the gravity sedimentation. The wash period is further shortened by employing a vessel with a flat shallow configuration for shortening the sedimentation path length of the aggregated red cells. A non-turbulant removal of the resultant broad shallow layer of sedimented red cells is achieved by carefully tilting the vessel after the sedimentation step so as to induce the sedimented red cells to slide or shift into a funnel configuration within the vessel. After the red cells have shifted into a funnel configuration, they are allowed to stand in that configuration so as undergo further concentration. As the red cells become packed, an elutriation of the intercellular fluids occurs. The resultant packed red cells are then carefully drained from the bottom of the funnel configuration for reinfusion into the patient. The period of the wash cycle is sufficiently short that a patient's shed blood can often be recovered during an operation and then washed and reinfused into the same patient during the same operation or shortly thereafter. Autologous transfusions are useful in cases where there is a shortage of blood or where the safety of donor blood is in question.

Autotransfusion systems can often be employed during a surgical procedure to recover and wash shed blood for re-infusion into the patient when donated blood is scarce or unavailable or when there is concern regarding the safety of the donated blood. The autotransfusion system may employ an aspiration system for recovering the shed blood. During the aspiration process, shed blood may be aspirated and directed through a gross clot pre-filter and into a collection vessel. Anticoagulant must be added to the collected blood to prevent clot formation within the collection vessel.
The mixture of collected blood and anticoagulant may be washed by the addition of a wash solution. The wash solution serves to dilute the blood. After dilution with the wash solution, the red cells may be separated from the diluted blood mixture by centrifugation or by gravity sedimentation. During centrifugation and/or gravity sedimentation, the red cells sediment and collect at the bottom of the vessel as packed red cells. The sedimentation of the red cells causes a substantial elutriation of various fluids and particles from packed red cells, including plasma, tissue fluids, anticoagulant, and washing solution. The packed red cells are suspended in residual supernatant. The packed red cell product may then be removed and transferred to a reinfusion bag for reinfusion into the patient from whom it was taken.
Although autotransfusion systems find wide application, their utility is mitigated by the slowness of the gravity sedimentation step and/or the complexity and labor involved with the centrifugation step. What is needed is an autotransfusion system which employs a simple but accelerated gravity sedimentation step for reducing the time delay between collection and reinfusion.


The invention relates to an exterior mirror simulation with image data recording and a display of the recorded and improved data for the driver of a motor vehicle. The display on a display device shows the data in a way chosen by the driver or the vehicle manufacturer.

1. Field of the Invention
The invention relates to an exterior mirror simulation with image data recording and a display of the recorded and improved data for the driver of a vehicle.
The display on a display device shows the data in a way favored by the driver and/or vehicle manufacturer.
2. Description of the Related Art
Several solutions for recording image data and its display for the driver of a vehicle are known in the prior art. The image recording is done by one or several cameras installed in the vehicle. The different assistance systems process the data from the captured image in very different ways.
In US patent application having publication number 2008/0159594, a system is known which records images from the surroundings of the vehicle with a fish-eye lens. Image data is recorded with great distortion through this wide-angle lens. The image data recorded by the camera pixels are rectified block by block. The display of the image is done with the rectified image data, since an image of the surroundings of the vehicle is required.
A camera for assisting reversing is known in DE 102008031784. The distorted camera image is edited and rectified, which leads to an undistorted image. This is then further processed, in order to optimise the perspective for reversing.


The invention provides and a highly-dispersed supported catalyst that has a reduced average particle size of catalytic metal particles and is also supported by a porous support material. A method of preparing a supported catalyst that can reduce the average particle size of catalytic metal particles supported by a support material includes first mixing a charged support material with a solution containing a polymer electrolyte having a charge opposite to that of the support material to adsorb the polymer electrolyte on the support material. Next, the support material having the polymer electrolyte adsorbed thereon is mixed with a solution containing a catalytic metal precursor ion having a charge opposite to that of the polymer electrolyte to adsorb the catalytic metal precursor ion on the support material having the polymer electrolyte adsorbed on it. Finally, the catalytic metal precursor ion adsorbed on the support material having the polymer electrolyte adsorbed thereon is reduced to a catalytic metal in a reducing solution.

1. Field of the Invention
The present invention relates to a catalyst and a method of preparing the same. More particularly, the present invention describes a supported catalyst and a method of preparing the same.
2. Description of the Related Art
Supported catalysts are widely used to accelerate the chemical reaction rate in various applications. It is well known that a supported catalyst consists of a catalyst component and a porous support material component. The catalyst component is attached to a surface of the porous support material component. In general, since many pores are present in a porous support is material, the porous support material has a very large surface area. Such a large surface area provides many positions in which many catalyst particles can be dispersed.
For example, a carbon-supported metal catalyst uses a porous carbon particle as a support material and a catalytic metal particle as a catalyst. Such a carbon-supported metal catalyst is used in an electrode of a fuel cell. More specifically, a carbon-supported metal catalyst is used in a cathode and/or an anode in a phosphoric acid fuel cell (PAFC), a proton exchange membrane fuel cell (PEMFC), or a direct methanol fuel cell (DMFC).
The catalyst accelerates the rate of electrochemical oxidation of a fuel and/or the rate of electrochemical reduction of oxygen. The carbon particle of the carbon-supported metal catalyst has a dual role as a support material and as an electronic conductor. Platinum and platinum/ruthenium alloy, for example, are frequently used as a catalytic metal particle.
Typically, a supported catalyst is prepared by adding a catalytic metal precursor solution to a dispersion of support material so that the catalytic metal precursor adsorbs onto the support material. Then a solution of a reducing agent is added to the dispersion to reduce the catalytic metal precursor adsorbed on a surface of the support material to a catalytic metal particle (see, U.S. Pat. No. 5,068,161). Finally, a freeze-drying is performed to obtain supported catalyst powders.
It is well known that one of main factors that affect the catalytic activity of a supported catalyst is the total surface area of supported catalytic metal particles. The surface area of the catalytic metal particles is, in turn, affected by the average particle size of catalytic metal particles and the amount of the catalytic metal particles present on the support. If the amount of the catalytic metal particles on the support is constant, the average particle size of the catalytic metal particles is inversely proportional to the total surface area of the supported catalytic metal particles. If an average particle size of the catalytic metal particles is constant, the amount of the catalytic metal particles on the support is directly proportional to the total surface area of the supported catalytic metal particles.
Thus, one of the important technical objects in the supported catalyst field is to produce smaller supported catalytic metal particles than a conventional supported catalyst.
In a fuel cell such as a PAFC, PEMFC, or DMFC, as the activity of a carbon-supported metal catalyst contained in the electrode increases, the power density of electricity generation in the fuel cell increases while maintaining energy efficiency. Accordingly, the ratio of power generation to production costs of the fuel cell stack increases and the ratio of power generation to the weight or volume of the fuel cell stack increases.
For a supported catalyst prepared using the conventional method, as the amount of the catalytic metal particles on a support increases, the average particle size of the catalytic metal particles tends to increase as well. Due to this phenomenon, there is a limit on the improvement of the catalytic activity of a supported catalyst.
Further, although the size of the catalytic metal particles on the support can be reduced by preparing them according to the conventional method, the decrease of the average particle size of the catalytic metal particles also has a limit.
Thus, there is a need to develop a technique that can reduce the average particle size of catalytic metal particles to be placed on a support material while increasing or maintaining the conventional amount of catalytic metal particles supported.

Supported catalyst and method for preparing the same


A method is provided that can be used for modifying a control parameter associated with a digital subscriber line (DSL) service. Initially, a real-time performance parameter is received from a first termination unit that is coupled to an DSL circuit. The real-time performance parameter is measured at the termination unit after the termination unit is provisioned and after the DSL circuit is placed in-service. A value of a control parameter associated with the DSL circuit can be modified based on the measured real-time performance parameter. Further, activity over the DSL circuit can be monitored in real-time and when usage of the DSL circuit is below a threshold, the provisionable service parameter that corresponds to the control parameter is modified. Moreover, a first re-provisioning cycle between the first termination unit and a second termination unit coupled to the DSL circuit can be initiated using the provisionable service parameter.

Digital subscriber line (DSL) has quickly emerged as a high quality solution for high speed Internet access and other services associated with high speed Internet services, such as, voice over Internet protocol (VoIP) and streaming video services. DSL can transmit both voice and data simultaneously over an existing, single copper pair up to 18,000 feet long. Since DSL can utilize existing copper telephone lines, the service costs associated with DSL is relatively low for service providers and for customers. Moreover, since data can be transmitted relatively quickly using DSL, it is a very attractive option for providing high-speed access to end users.
Traditional plain old telephone service (POTS) uses a narrow 4-kHz baseband frequency to transmit analog voice signals, and current modem technology can achieve a data transmission rate of up to 56 kb/s. DSL, e.g., asymmetric DSL (ADSL), can increase the usable frequency range from 4 kHz to 1.1 MHz and can provide a data transmission rate up to 8 Mb/s. Further, frequency division multiplexing (FDM) can allow ADSL to create multiple frequency bands that can be used to carry data simultaneously with POTS signals over the same copper pair. The lower 4-kHz frequency range is reserved for POTS, the middle frequency band is used to transmit upstream data and the larger, higher frequency band is used to transmit downstream data.
Discrete multi-tone (DMT) modulation is the American National Standards Institute (ANSI) standard T1.413 line code. DMT modulation is used to divide the data bandwidth into 256 subchannels, or tones, that range from 20 kHz to 1.1 MHz for ADSL. Upstream data transfer frequencies range from 20 kHz to 160 kHz and downstream data transfer frequencies range from 240 kHz to 1.1 MHz. The remaining tones are used as guard bands for dividing the three frequency bands, and one pilot tone is used in each data stream, both upstream and downstream, for timing purposes. Each tone, or channel, has a spacing of 4.3 kHz and each tone supports a maximum number of 15 bits, which is limited by the signal-to-noise ratio on the channel. Since the tones in the higher frequencies are subject to higher attenuation and noise, the number of bits per tone can be fewer than that in the lower frequencies.
In addition to the normal data bits, an embedded operations channel (EOC) is provided as part of the ADSL protocol for communication between the ATU-C and the ATU-R to provide in-service and out-of-service maintenance, to retrieve a limited amount of ATU-R status information, and to monitor ADSL performance.
Typically, the optimization of the data transmission channels used for DSL data transport, e.g., VoIP and video, is largely ignored due to technical and economic factors. Without optimization, DSL circuits are either over-engineered or under-engineered for performance. Over engineered circuits operate at sub-optimum rates and deliver less performance to the customer. Under-engineered circuits experience frequent data errors that result in increased peer-to-peer communications required to perform re-transmissions of data packets. This yields a reduced throughput to the customer. Some under-engineered circuits experience error rates severe enough to cause service interruption or the inability to establish the data channel when initially requested by the customer.
Accordingly, there is a need for a system and method for optimizing digital subscriber line data service.

System and method for optimizing digital subscriber line based services