Puncture sequences S1, S2, etc. for code rates R1, R2, etc. less than a maximum code rate Rmax are defined subsets of a maximum rate puncture sequence Smax that corresponds to the maximum code rate Rmax. Each puncture sequence Si for a code rate Ri is related to the puncture sequence Si−1, of the previous code rate Ri−1, and preferably S1⊂S2⊂ . . . ⊂Smax−1⊂Smax. The puncture sequences are groups of one or more memory elements, each of which is a variable degree, a variable node location, a check degree, or a check node location. A method for deriving such a puncture sequence for variable code rates is also disclosed.

Low-density parity-check (LDPC) codes have recently been the subject of increased research interest for their enhanced performance on additive white Gaussian noise (AWGN) channels. As described by Shannon's Channel Coding Theorem, the best performance is achieved when using a code consisting off very long codewords. In practice, codeword size is limited in the interest of reducing complexity, buffering, and delays. LDPC codes are block codes, as opposed to trellis codes that are built on convolutional codes. LDPC codes constitute a large family of codes including turbo codes. Block codewords are generated by multiplying (modulo 2) binary information words with a binary matrix generator. LDPC codes uses a check parity matrix H, which is used for decoding. The term low density derives from the characteristic that the check parity matrix has a very low density of non-zero values, making it a relatively low complexity decoder while retaining good error protection properties.
The parity check matrix H measures (N−K)×N, wherein N is number of elements in a codeword and K is the number of information elements in the codeword. The matrix H is also termed the LDPC mother code. For the specific example of a binary alphabet, N is the number of bits in the codeword and K is the number of information bits contained in the codeword for transmission over a wireless or a wired communication network or system. The number of information elements is therefore less than the number of codeword elements, so K<N. FIGS. 1A and 1B graphically describe an LDPC code. The parity check matrix 20 of FIG. 1A is an example of a commonly used 512×4608 matrix, wherein each matrix column 22 corresponds to a codeword element (variable node of FIG. 1B) and each matrix row 24 corresponds to a parity check equation (check node of FIG. 1B). If each column 22 of the matrix H includes exactly the same number m of non-zero elements, and each row 24 of the matrix H includes exactly the same number k of non-zero elements, the matrix 20 represents what is termed a regular LDPC code. If the code allows for non-uniform counts of non-zero elements among the columns 22 and/or rows 24, it is termed an irregular LDPC code.
Irregular LDPC codes have been shown to significantly outperform regular LDPC codes, which has generated renewed interest in this coding system since its inception decades ago. The bipartite graph of FIG. 1B illustrates that each codeword element (variable nodes 26) is connected only to parity check equations (check nodes 28) and not directly to other codeword elements (and vice versa). Each connection, termed a variable edge 30 or a check edge 31 (each edge represented by a line in FIG. 1B), connects a variable node 26 to a check node 28 and represents a non-zero element in the parity check matrix H. The number of variable edges 30 connected to a particular variable node 26 is termed its degree, and the number of variable degrees 32 are shown corresponding to the number of variable edges 30 emanating from each variable node 26. Similarly, the number of check edges 31 connected to a particular check node 28 is termed its degree, and the number of check degrees 34 are shown corresponding to the number of check edges 31 emanating from each check node 31. Since the degree 32, 34 represents non-zero elements of the matrix H, the bipartite graph of FIG. 1B represents an irregular LDPC code matrix. The following discussion is directed toward irregular LDPC codes since they are more complex and potentially more useful, but may also be applied to regular LDPC codes with normal skill in the art.
Irregular codes can be designed for many different symmetric channels via density evolution and genetic hill-climbing algorithms (i.e., Differential Evolution) by adjusting variable edge polynomial λ(x) and check edge polynomial ρ(x), defined as:
      λ              (      x      )        =                    ∑                  i          =          2                          d          l                                            λ          i                                  x                      i            -            1                                                                    and                                                            ρ                                (            x            )                                =                  ∑                  i          =          2                          d          r                                            ρ          i                                  x                      i            -            1                              where {λ2, λ3, . . . λdl} and {ρ2, ρ3, . . . ρdr} are the edges distributions indicating the fraction of edges 30, 31 connected to variable and check nodes of degrees {2, 3, . . . dl} and {2, 3, . . . dr}, respectively, out of the total number of edges. The edge distributions determine the asymptotic performance of the code ensemble, the code rate of the ensemble, and any code realizations derived from the distributions. The coding rate R for an LDPC code is R=K/(N−P), wherein P is the number of punctured elements, detailed below. Preferably, a transmission can be sent using a plurality of adaptive coding rates.
FIG. 2A is a prior art logical block diagram showing operation of a discrete communication system 36A using an LDPC coding scheme of multiple coding rates for its error control. An information source 38 outputs a K dimensional sequence of information bits s into a transmitter 39A, the transmitter including at least an encoder 40A, a modulation block 42, and storage 35A, 37A. An LDPC encoder 40 encodes the sequence s into an N dimensional codeword t by accessing a stored LDPC mothercode definition 37A and one of several stored puncture sequences 35A, one puncture sequence corresponding to one code rate. The codeword t is broken up into sub-vectors, which are then modulated and up-converted at a modulation block 42 and transmitted as a vector x of the sub-vectors over one or more channels 44. Additive white Gaussian noise n is added at the channel and/or from system hardware, so that the vector y=x+n is input into a receiver 45A. The receiver 45A includes at least a demodulation block 46, a decoder 48A, and memory storage for the same LDPC mother code 37A and the same puncture sequences 35A used by the transmitter 39A. Since x and n are uncorrelated and the modulation is memoryless, the received vector y can be demodulated symbol-by-symbol at a demodulating block 46, producing a hard decision vector {circumflex over (t)} on the received information vector t. Probabilities of the decision being correct are also calculated at the demodulation block 46, and all this is input into an LDPC decoder 48A that iteratively decodes the entire received code block and outputs a decoded information vector ŝ to an information sink 50.
The two prior art LDPC coding systems known to the inventor require significant non-volatile memory for each coding rate for a single mother code. In a first prior art approach, a different LDPC code is designated for each coding rate and channel (i.e., different code realizations from different λ(x) and ρ(x) corresponding to the desired code rates). This approach uses one LDPC code for each coding rate, and may increase substantially when the set of code rates is large and/or when code words are long. The storage requirements can render this approach prohibitive for adaptive coding and modulation schemes operating in slowly varying channels.
The second known prior art approach is to take a single LDPC code and puncture codeword elements using multiple puncturing sequences chosen at random using puncturing probabilities. This approach requires storage of multiple puncturing sequences, one for each code rate, which may become prohibitive for a large set of coding rates and/or long codeword lengths. FIG. 3 illustrates the storage requirements of such a system. To support all possible code rates of a punctured LDPC mother code, the system would need to store N−K different puncture sequences 52. Each horizontal line represents a unique stored puncture sequence 52, indexed as S1, S2, S3, . . . SN—K, that applies to a specific coding rate R1, R2, R3, . . . RN−K. The total memory requirement for such a system is
      ∑          i      =      1              N      -      K          iuncompressed memory elements.
Besides substantial amounts of memory required to store prior art puncturing sequences for various coding rates, the determination of the puncturing sequences is itself computationally intensive. Like the coding systems themselves, the prior art reveals at least two distinct methods for designing a puncture sequence. The first method is based on linear programming to determine puncturing probabilities that maximize the puncturing fraction:
      p          (      0      )        =            ∑              j        =        2                    d        l                                λ        j        ′                          π        j                  (          0          )                    for a given signal to noise ratio (SNR, or bit/symbol energy to noise power spectral density Eb/N0) threshold, wherein λ′j represents the fraction of variable nodes 26 of degree j. The other prior art approach to puncture sequence design is based on differential evaluation based on Density Evolution, which is somewhat more complex than the linear programming method described immediately above with near identical results. Each of these approaches for designing the puncture sequences are very computationally expensive, and their resulting sequences themselves require so much storage as to be potentially prohibitive for an adaptive coding system.
Thus, each of the known prior art approaches require substantial amounts of storage to implement a wide variety of code rates. It is anticipated that neither of the prior art approaches are suitable for future communication systems that employ adaptive coding and implement a wide range of coding rates. Additionally, each of the two noted prior art approaches in designing puncture sequences are computationally intensive. What is needed in the art is a more elegant set of puncture codes that will not require so much storage as to make their use prohibitive in the adaptive coding rate communications systems that represent what may be a large portion of future communications. Ideally, such an elegant set of puncture codes would also submit to a more straightforward method of determining them, so that more sets of such codes could be developed and optimized for different applications to close further on the theoretical Shannon capacity limit.

Low-density parity-check codes for multiple code rates


A video sharing system is described to annotate and navigate tourist videos. An example video sharing system enables non-linear browsing of multiple videos and enriches the browsing experience with contextual and geographic information.

Everyday tourists take and capture video of a trip or experience. Some tourist videos are concerned with capturing people, while other capture layout of a specific location or landscape. After capturing the video, a tourist will often want to annotate the video with text describing landmarks, enabling them to remember the experience. Annotating the video makes it possible for the tourist to share their experience with others interested in the same point of interest. The tourist may also want to remember a specific location or experience captured on video.
Annotating and navigating video may present many obstacles. For example, when a user attempts to annotate a video the labels are static and do not track the landmark throughout the video. Further, a tourist may also have difficulty navigating a video. For example, generally events and locations within a video are presented and stored sequentially. Therefore, if a tourist would like to cue a specific experience or location, the tourist must either play through the entire sequence of the video or fast forward, potentially skipping over other interesting events.

City scene video sharing on digital maps


An analog-to-digital conversion circuit includes an analog-to-digital conversion unit configured to analog-to-digital convert an input voltage and generate a digital signal, a resolution control unit configured to: set a resolution of the analog-to-digital conversion unit to N (N is the natural number) bits, in a case where the input voltage is smaller than a first voltage, and set the resolution of the analog-to-digital conversion unit to N−M (1≦M<N, M is the natural number) bits in a case where the input voltage is larger than the first voltage, and a signal correction unit configured to: generate a corrected digital signal based on a boundary value and the digital signal, in a case where a value of the digital signal is larger than the boundary value and the input voltage is smaller than the first voltage.

1. Field
Exemplary implementations of the present invention relate to an analog-to-digital conversion circuit, an analog-to-digital conversion method, and an image sensor, which can decrease a non-linear error of a digital signal when performing analog-to-digital conversion.
2. Description of the Related Art
Recently, the demand for digital cameras has explosively increased with the development of visual communication using the Internet. Moreover, as mobile communication terminals mounted with a camera, such as a PDA (personal digital assistant), an IMT-2000 (International Mobile Telecommunications-2000) terminal and a CDMA (code division multiple access) terminal, are popularized, the demand for small-sized camera modules has increased.
A camera module includes an image sensor. In general, an image sensor refers to a device that converts an optical image into an electrical signal. Examples of common image sensors include a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor) image sensor.
The CCD has a complicated driving scheme and high power consumption. Furthermore, since the number of mask processes required for fabrication is relatively large, fabrication processing is complex. In addition, since a signal processing circuit cannot be realized in a chip, it is difficult to realize the CCD in one chip.
However, in the CMOS image sensor, monolithic integration of control, driving, and signal processing circuits in a single chip is possible. Accordingly, attention has recently been paid to the CMOS image sensor. Also, when compared to a CCD image sensor, the CMOS image sensor has a lower cost due to a low voltage operation, low power consumption, compatibility with peripheral devices, and the recued complexity a standard CMOS fabrication process.
The CMOS image sensor includes a plurality of unit pixels. The pixels output analog signals (hereinafter, referred to as "pixel signals") with voltage levels corresponding to light incident thereon. The CMOS image sensor generates pixel data by analog-to-digital converting these pixel signals, and the pixel data are used in storing and outputting an image. The CMOS image sensor includes an analog-to-digital conversion circuit which is used to convert an analog signal into a digital signal, for analog-to-digital conversion of a pixel signal.
In general, as a resolution increases, the power consumption and an analog-to-digital conversion time of an analog-to-digital conversion circuit increase. Meanwhile, shot noise increases as the intensity of light incident on a pixel increases. Due to this fact, as the intensity of light increases, the magnitude of quantization noise permitted in the analog-to-digital conversion circuit increases. Accordingly, in a case where the intensity of light incident on a pixel is large, data corresponding to the incident light may be generated with no problem even though a resolution of analog-to-digital conversion is relatively low, when compared to a case where the intensity of light is small. Accordingly, an analog-to-digital conversion circuit that analog-to-digital converts a pixel signal by applying different resolutions based on the intensity of light obtained by determining an approximate intensity of light incident on a pixel (the level of a pixel signal). In the case of using such an analog-to-digital conversion circuit, power consumption and an analog-to-digital conversion time may be decreased.
FIG. 1 is a configuration diagram of a related analog-to-digital conversion circuit in which different resolutions are applied according to the level of an input voltage.
Referring to FIG. 1, an analog-to-digital conversion circuit includes a comparator 110, a resolution control unit 120, and an analog-to-digital conversion unit 130.
The comparator 110 is configured to compare an input voltage VIN to a reference voltage VREF, and output a comparison result. For example, the comparator 110 may output a logic high level in the case where the input voltage VIN is larger than the reference voltage VREF, and may output a logic low level in the case where the input voltage VIN is smaller than the reference voltage VREF. When offset is not exit in the comparator 110, the reference voltage VREF should be a boundary. where the resolution of a digital signal DIG<0:N−1>, acquired by analog-to-digital converting the input voltage VIN, changes. The value of the digital signal DIG<0:N-1> should be continuous at the boundary.
The resolution control unit 120 is configured to determine, in response to the comparison result of the comparator 110, the resolution of the analog-to-digital conversion by the analog-to-digital conversion unit 130. For example, in a case where the comparator 110 determines (in the case where the output of the comparator 110 has the logic low level) that the input voltage VIN is smaller than the reference voltage VREF, the resolution control unit 120 determines the resolution of the analog-to-digital conversion unit 130 as N bits. In a case where the comparator 110 determines (in the case where the output of the comparator 110 has the logic high level) that the input voltage VIN is than the reference voltage VREF, the resolution of the analog-to-digital conversion unit 130 as N−M bits.
The analog-to-digital conversion unit 130 is configured to analog-to-digital convert the input voltage VIN based on the resolution determined by the resolution control unit 120 and generate the digital signal DIG<0:N−1>.
The comparator may be configured using an operational amplifier or the like. In general, in a semiconductor circuit, such as an operational amplifier, an offset voltage exists. The offset voltage may be caused by an error in a design, a semiconductor fabrication process, an error in a package, or the external environment. In the case where a positive offset exists, the comparator 110 outputs a logic high level if the input voltage VIN is larger than the sum of the reference voltage VREF and an offset voltage. Otherwise, the comparator 110 outputs a logic low level. In the case where a negative offset exists, the comparator 110 outputs a logic high level if the input voltage VIN is larger than the difference between the reference voltage VREF and an offset voltage. Otherwise, the comparator 110 outputs a logic low level. FIG. 2 is a graph explaining a non-linear error occurring due to an offset that exists in the comparator 110. FIG. 2 shows the digital signal DIG<0:N−1> according to the magnitude of the input voltage VIN.
L1 shows the digital signal DIG<0:N−1> based on a magnitude of the input voltage VIN, in a case where an offset does not exist in the comparator 110. L2 shows the digital signal DIG<0:N−1> based a magnitude of the input voltage VIN, in a case where a positive offset exists in the comparator 110. L3 shows the digital signal DIG<0:N−1> based on a magnitude of the input voltage VIN, in the case where a negative offset exists in the comparator 110.
In an ideal case, the slope (proportional to a resolution) of a graph should be changed at a point where the input voltage VIN becomes the same as the reference voltage VREF, as in L1, and the graph should be continuous at the point where the input voltage VIN is the reference voltage VREF. However, in the case where a positive offset exists in the comparator 110, the slope of a graph is changed at a point where the input voltage VIN is the same as the sum of the reference voltage VREF and an offset voltage VOFF, as in L2, and the graph is not continuous at that point and a non-linear error occurs. Also, in the case where a negative offset exists in the comparator 110, the slope of a graph is changed at a point where the input voltage VIN is the same as the difference between the reference voltage VREF and the offset voltage VOFF, as in L3, and the graph is not continuous at that point and a non-linear error occurs. Such non-linear errors exert negative influences on the precision of an analog-to-digital convertor.

Analog-to-digital conversion circuit, analog-to-digital conversion method, and image sensor

Industry-University Cooperation Foundation Hanyang University


A technique that facilitates application synchronization with a reservation protocol at a sender without application receiver participation in a computer network. According to the novel technique, the sender sends a path request message to a reservation receiver and may include a request for fast path failure notification to be returned to the sender. The reservation receiver (e.g., a reservation receiver proxy upstream from the application receiver) receives the path request, and in response, returns a reservation request message to the sender, including a request for fast reservation failure notification also to be sent to the sender (e.g., in response to detecting the fast path failure notification request, local policy/configuration, etc.). In the event that an intermediate node between the sender and reservation receiver detects an error during the path request or reservation request, the intermediate node sends corresponding fast failure notification to the sender. The sender may then synchronize, e.g., an application with the reservation protocol, based on receipt of a fast failure notification or a successful reservation request message.

1. Field of the Invention
The present invention relates to computer networks and more particularly to facilitating application synchronization with a reservation protocol at a sender without application receiver participation in a computer network.
2. Background Information
A computer network is a geographically distributed collection of interconnected subnetworks for transporting data between network nodes, such as computers. A local area network (LAN) is an example of such a subnetwork. The network's topology is defined by an arrangement of client nodes that communicate with one another, typically through one or more intermediate network nodes, such as routers or switches. As used herein, a client node is a network node that is configured to originate or terminate communications over the network. In contrast, an intermediate network node is a node that facilitates routing data between client nodes. Communications between network nodes are typically effected by exchanging discrete packets of data according to predefined protocols. In this context, a protocol consists of a set of rules defining how the nodes interact with each other.
The data packets transferred among the network nodes may include fixed-sized data cells and/or variable-sized data frames. Each data packet typically comprises "payload" data prepended ("encapsulated") by at least one network header formatted in accordance with a network communication protocol. The network headers include information that enables the client nodes and intermediate nodes to route the packet efficiently through the computer network. Often, a packet's network headers include at least a data-link (layer 2) header and an internetwork (layer 3) header, as defined by the Open Systems Interconnection (OSI) Reference Model. The OSI Reference Model is generally described in more detail in Section 1.1 of the reference book entitled Interconnections Second Edition, by Radia Perlman, published September 1999, which is hereby incorporated by reference as though fully set forth herein.
In operation, a client node may send a data packet to a network interface of an intermediate network node. Thereafter, the intermediate network node receives the packet and forwards the packet to its next destination. For example, the intermediate network node may perform a layer-2 switching function that simply re-directs the packet from one network interface to another based on the contents of the packet's data-link header. Alternatively, the intermediate network node may perform a layer-3 routing function, or forwarding decision, that selects the most appropriate network interface to forward the packet based on the contents of the packet's internetwork header.
Data packets are used to transport many forms of information, including voice and video information, over networks and subnetworks. For instance, voice information may be transmitted in accordance with the Voice over Internet Protocol (VoIP). VoIP refers to a group of technologies used to transmit voice information over data networks from a source node to a destination node. The source and destination nodes employ voice agents that convert voice information from its traditional telephony form to a form that is suitable for packet transmission. In other words, the source node's voice agent encodes, compresses, and encapsulates the voice information into a plurality of data packets, and the destination node's voice agent performs complementary functions to de-encapsulate, uncompress, and decode the VoIP packets. Examples of voice agents include IP telephones, VoIP gateways, certain private branch exchanges (PBXs), personal computers (PCs) running communication applications, network devices providing voice gateway services, etc. Also, video information may be transmitted in accordance with Video on Demand (VoD) standards known to those skilled in the art in a similar manner. For instance, a VoD content server may supply video data streams to one or more "set-top-boxes"of users. Notably, the use of VoIP and VoD are examples of applications (e.g., at an application levels) that a node within the network may operate. Those skilled in the art will understand that other applications may also be operated at network nodes.
A source node (sender) may be configured to transfer a unidirectional stream of data packets, or a "data flow," to a destination node (receiver) in a data network. The data flow may comprise, for example, data or voice/video information. The data flow is unidirectional in that data travels one-way from the sender to the receiver. The logical procession of intermediate network nodes that transmit and receive data packets from the sender to the receiver defines the data flow's data path. A first node that is nearer the receiver in the data flow's data path than a second node in the flow is said to be "downstream" from the second node. Likewise, a first node that is nearer the sender in the data flow's path than a second node in the flow is said to be "upstream" from the second node.
Some data flows are associated with a certain level of quality of service (QoS). For example, a data flow's QoS may specify minimum end-to-end latency or bandwidth requirements needed to support the flow. The Resource ReSerVation Protocol (RSVP) is a network-control protocol that enables source and destination nodes to "reserve" the necessary resources to establish the data flow in accordance with the flow's required QoS. RSVP works in conjunction with routing protocols to, e.g., reserve resources along a data flow between the source and destination nodes to establish a level of QoS required by the data flow. RSVP is defined in R. Braden, et al., Resource ReSerVation Protocol (RSVP), Request For Comments (RFC) 2205, which is hereby incorporated by reference as though fully set forth herein.
In a typical arrangement, the sender sends an RSVP Path message identifying itself and indicating the bandwidth needed by the data flow. The Path message proceeds to the receiver following the flow's data path and each intermediate network node may update an optional "Adspec" object of the Path message. The Adspec object contains, inter alia, information about the properties of the data flow, such as available services, delay, and bandwidth estimates. Adspec objects may be generated by senders or by intermediate nodes, and are modified as they travel from one node to another. An Adspec object advertises the possible service parameters composed of the properties of all previous-hop nodes upstream. Namely, the arriving Adspec object is combined with the node's own parameters and service conditions, and then forwarded to the next node. A receiver can use the Adspec information to predict the end-to-end QoS, to choose the most appropriate service and to scale its QoS request according to the current possibilities of the network.
The receiver receives the Path message and may take into account contents of the optional Adspec object in the Path message to determine the specifics of the reservation requests it will generate for the flow. The receiver generates a "request for resources" in the form of an RSVP reservation request (Resv message) which travels hop-by-hop back to the sender. Within the Resv message is a "FlowSpec" object, which contains, inter alia, an indication of a peak expected traffic (e.g., bandwidth) from the sender (Tspec), and the requested traffic value to be reserved (Rspec). At each hop, the corresponding intermediate network node sets aside ("assigns") sufficient resources to provide the requested bandwidth for the desired data flow. These assigned resources are consequently made available to the data flow so that the data packets of the flow get appropriate QoS treatment (i.e., the data flow is "admitted").
If sufficient resources are not available, an intermediate network node may "reject" the Resv message (i.e., does not continue forwarding it), generate a reserve error (ResvErr) message, and forward the ResvErr message downstream over the flow to the receiver. The receiver eventually receives the ResvErr message and concludes that the reservation has failed. A receiver whose Resv message has been rejected may attempt to acquire less resources by sending another Resv message requesting less bandwidth, or the receiver may re-attempt later to acquire the resources by re-transmitting another Resv message. Senders are unaffected by this process, and they continue to send Path messages to refresh their state. Notably, PathErr and ResvErr messages are typically sent and processed hop-by-hop by the intermediate nodes along the path between the sender and the receiver, as will be understood by those skilled in the art.
RSVP signaling may be used between a sender and a receiver to perform resource reservation for particular applications requiring QoS guarantees (e.g., VoIP, VoD, etc.). In this case, it is essential that the RSVP reservation establishment be tightly synchronized with the application. For example, VoIP calls should not "ring" the called phone (the receiver) until the RSVP reservation is completed in order to avoid "ghost" rings as will be understood by those skilled in the art. Generally, the application synchronization with RSVP reservation incorporates cooperation of the end-points (i.e., sender and receiver) of both the application and the reservation since both end-points are involved in the signaling of the application and the reservation. An example application synchronization is described in detail in RFC 3312, entitled Integration of Resource Management and Session Initiation Protocol (SIP), updated by RFC 4032, entitled Update to the Session Initiation Protocol (SIP), Preconditions Framework, both of which are hereby incorporated by reference as though fully set forth herein.
In a typical example of application synchronization, e.g., VoIP, a sender may wish to initiate an application session (e.g., call) to a receiver, for which resources need to be reserved to ensure QoS to the session. Accordingly, the sender requests the session is by sending an "offer" to the receiver, and including within the offer an indication that resources ought to be reserved before the session establishment can be completed (i.e. resource reservation is a "precondition"). The receiver may then respond to the offer and provide information details about the session but may put the session establishment on hold until resource reservation is completed. The sender may then trigger reservation establishment (e.g. by sending an RSVP Path message). The receiver may answer the resource reservation request (e.g. by sending an RSVP Resv message). Once the sender receives the answer indicating that the requested resources have been reserved, the sender acknowledges the preconditions to the receiver at the application level signaling. The receiver may then resume establishment of the application session (e.g., and acknowledge the establishment to the sender so that it may also establish the session). In this manner, the application and resource reservation have been successfully synchronized (i.e., the application session has not been established—and for example, the remote phone has not rung—without acknowledging first that the requested resources have been reserved).
In some network environments, however, the receiver is not configured for resource reservation (e.g., RSVP) or is not capable of participating in resource reservation. In many of these situations, a reservation receiver proxy may be located upstream from the receiver (an "application receiver"). Here, the reservation receiver proxy (a "reservation receiver") performs the resource reservation signaling on behalf of the application receiver. As such, the application receiver is not involved with the resource reservation. Because of this, the application receiver may not participate in the synchronization between the resource reservation and the application establishment. Also, as the reservation receiver is not an end-point for the application, it too may not participate in the synchronization between the resource reservation and the application establishment. In particular, a reservation receiver proxy may be unaware of application level signaling, and thus may be unable to effectively communicate synchronizing messages with the sender. For instance, any admission rejection or errors resulting from the reservation of resources are generally sent to the reservation receiver. According to reservation protocols (e.g., RSVP), the sender may not be notified of this failure. Conventionally, the application receiver would notify the sender of the failure, but as mentioned above, the reservation receiver and application receiver are separate nodes, so this may not be the case (e.g., or possible). It would be beneficial, then, for the sender to synchronize the application with the reservation protocol by itself.
An example of a reservation receiver proxy may be illustrated with reference to VoD applications. VoD content providers may wish to prevent the distribution of VoD content to set-top-boxes ("application receivers") unless the appropriate resources are reserved (e.g., for admission control), as will be understood by those skilled in the art. Many set-top-boxes, however, may not be configured for resource reservation (e.g., RSVP), and it may be difficult to otherwise "upgrade" the configuration of the boxes. A reservation receiver proxy may be placed upstream from the set-top-boxes to handle the resource reservation, but, as mentioned above, there are problems associated with application synchronization with a reservation receiver proxy.
Various solutions have been proposed for application synchronization at a sender without participation from the application receiver. One such solution consists of the sender attempting to "guess" the status of the reservation. For instance, where a resource reservation request (e.g., Path message) has been sent by the sender, if the sender has not received a response (e.g., Resv message) within a configurable length of time, the sender may assume that the reservation has failed. While this solution allows for application synchronization, it may be slow (i.e., based on the configured length of time sufficient to declare a failed reservation), and may not account for failures after an initial reservation establishment (e.g., an established reservation may be rejected later in response to network element failures), as will be understood by those skilled in the art.
Another proposed solution is to have the reservation receiver proxy generate a "fake" path request error message (e.g., PathErr) to send to the sender in response to receiving a reservation request error message (e.g., ResvErr). In this manner, the "fake" path request error message ("fake" because it is not conventional for a reservation receiver to send path request error messages to the sender in response to reservation failures) may inform the sender of the reservation failure. This approach also suffers from various limitations, including, e.g., a slow response time. For instance, when an intermediate network node between the reservation receiver and sender detects a reservation error, the reservation error message is sent and processed hop-by-hop downstream to the reservation receiver. The reservation receiver may then generate the "fake" path request error message, which is then sent and processed hop-by-hop upstream to the sender. This hop-by-hop processing may be time-consuming, and the solution, therefore, is suboptimally responsive. Also, this solution may be poorly scalable, since where a large network failure occurs, the reservation receiver proxy may be inundated with hundreds or thousands of error messages, resulting in a processing surge and additional delay.
Because tight application synchronization to a reservation protocol is essential (e.g., to interrupt corresponding data flows, etc.), as will be understood by those skilled in the art, minimizing the delays associated with informing the sender of a reservation failure is critical. One such way to minimize the delay with regard to error notifications is the use of a fast failure notification, or a "Notify" feature, as described in RFC 3473, entitled, Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE) Extensions, dated January 2003, which is hereby incorporated by reference in its entirety. In particular, a request (e.g., a Notify request) may be included within the path request or reservation request messages requesting that the intermediate node detecting an error send a fast failure notification along with the conventional error messages (e.g., PathErr and ResvErr, respectively). For example, the reservation receiver may request that a fast reservation failure notification (e.g., for a ResvErr) may be generated and sent to the reservation receiver in response to reservation request errors (i.e., without processing by other intermediate nodes). Also, the sender may request that a fast path failure notification (e.g., for a PathErr) be generated and sent to the sender in response to path request errors.
While the fast failure notification may accelerate the notification of reservation failures to the reservation receiver (e.g., a reservation receiver proxy), the reservation failure notifications are still addressed to, and processed by, the reservation receiver, so it does not help in providing failure notification to the sender. There remains a need, therefore, for a technique that tightly and efficiently synchronizes an application to a reservation protocol at a sender. In particular, a need remains for synchronization where the application level signaling and reservation level signaling terminate at different end-points (i.e., at an application receiver and a reservation receiver), e.g., without application receiver participation.

Facilitating application synchronization with a reservation protocol at a sender without application receiver participation


The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction.

The present invention relates generally to the production of fuel gas by the gasification of carbonaceous materials such as bituminous, or sub-bituminous coal in down-flow moving-bed gasifiers and employing catalytic material for enhancing the gasification cycle and, more particularly, to such gasification of carbonaceous materials wherein the catalytic material is recycled in the operation and with the recycled catalyst being uniformly distributed over the carbonaceous material.
Moving-bed gasifiers have a proven capability for the efficient conversion of chemical energy contained in carbonaceous materials such as coal, peat, biomass and the like, into product or fuel gases having relatively high BTU values. A highly efficient conversion of the solid carbonaceous material to fuel gas is achieved by employing a countercurrent flow operation in the gasifier whereby particulate carbonaceous material is converted to char and then ash as it flows downwardly in the gasifier countercurrently to an upwardly rising stream of air or air and steam so that the fuel gases are produced by an endothermic reaction with the carbonaceous material and char at relatively high temperatures. Also, this countercurrent flow operation allows some of the sensible heat in the fuel gas to be returned to the reaction zone.
Recent improvements in moving-bed gasifiers for the production of fuel gas from carbonaceous materials utilize a coal pyrolysis cycle in combination with the coal gasification cycle for increasing the coal conversion efficiency while reducing problems associated with the production of tars, coal agglomeration and caking, and the entrainment of fines in the fuel gas. Such an improved moving-bed gasifier is described in U.S. Pat. No. 5,145,490, issued Sep. 8, 1992, which is specifically incorporated herein by reference. In this patented gasifier, a closed end pressure vessel is provided with a discharge for the fuel gas that is in a location removed from the closed end of the pressure vessel so as to significantly reduce the carry over of tars and fines into the fuel gas. This patented gasifier is also provided with a pyrolyzer coaxially disposed within the pressure vessel where the coal is pyrolyzed in the presence of air before being discharged into the high temperature region of the gasifier near the upper end of the pressure vessel. This solid pyrolyzed material that is discharged from the pyrolyzer is in the form of char and descends through a gasification zone surrounding the pyrolyzer and onto a rotating grate. As this char descends through the gasification zone, steam and air are introduced through the base and top of the gasifier to endothermically react with the hot char to provide the gasification reactions for producing the fuel gas. These endothermic gasification reactions are limited to minimum temperatures of about 1700.degree. F. for bituminous coals and about 1500.degree. F. for sub-bituminous coals and thus limit the chemical conversion efficiency that can be achieved.
While not utilized in the gasification reaction described in the aforementioned patent, catalysts such as potassium compounds including potassium carbonate, potassium acid carbonate, and potassium chloride or other compounds such as sodium carbonate, sodium chloride, or calcium oxide have been previously used in gasification cycles to significantly increase the gasification rates even at endothermic gasification reaction temperatures as low as about 1200.degree.-1300.degree. F. Also, at temperatures of about 1400.degree.-1500.degree. F. an exothermic hydrogen/carbon reaction occurs to form methane which releases heat for continuing to drive the endothermic gasification steam/carbon and CO.sub.2 /carbon reactions utilized for producing the fuel gas at temperatures as low as about 1200.degree.-1300.degree. F. However, the problems associated with using catalysts as in previously known gasification systems such as described in the aforementioned patent, is the requirement for providing a uniform distribution of the catalyst across the bed of coal or char particulates in order to ensure the efficient use of the catalyst and, more importantly, the attendant economic problems associated with the loss of catalyst as it is discharged along with the ash from the gasifier. The separation of the catalyst from this ash creates a significant economic burden upon the utilization of catalyst in the gasification cycle due to the difficulties previously encountered during attempts to efficiently separate the catalyst from the ash.

Down-flow moving-bed gasifier with catalyst recycle

The United States of America as represented by the United States Department of Energy


The invention relates to a steam generator comprising a heating gas channel, which can be traversed in an approximately horizontal heating gas direction and in which at least one continuous heating surface is located, configured from a number of approximately vertical evaporator tubes, connected in parallel to allow the passage of a flow medium. The aim of the invention is to provide a method for starting a generator, which guarantees a high degree of operational safety, even for a steam generator with a particularly simple construction. According to the invention, to achieve this, at least several evaporator tubes are partially filled to a predeterminable desired level with unevaporated flow medium, prior to the impingement of the heating gas channel by a heating gas.

In a gas and steam turbine system, the heat contained in the expanded operating medium or heating gas from the gas turbine is used to generate steam for the steam turbine. The heat transfer takes place in a waste-heat steam generator downstream of the gas turbine, in which usually a number of heating surfaces are arranged for water preheating, steam generation and steam superheating. The heating surfaces are connected to the water-steam circuit of the steam turbine. The water-steam circuit normally contains several, e.g. three, pressure stages, each having an evaporator heating surface.
Several alternative design concepts are possible for the steam generator connected downstream of the heating gas end of the gas turbine as a waste-heat steam generator, i.e. as a once-through steam generator or as a circulating-steam generator. With a once-through steam generator, the heating of the steam generating tubes provided as evaporator tubes causes evaporation of the flow medium in the steam generator tubes in a single passage. In contrast to this, with a natural- or forced-circulation steam generator the circulated water is only partially evaporated during one passage through the evaporator tubes. The water not evaporated is re-supplied to the same evaporator tubes for further evaporation after removal of the generated steam.
A once-through steam generator is, in contrast to a natural- or forced-circulation steam generator, not subject to pressure limitation and therefore live steam pressures far above the critical pressure of water of (PKri≈221 bar) where there are still only slight differences in density between the liquid-similar and steam-similar medium, are possible. A high live steam pressure favors a high thermal efficiency and therefore low CO2 emissions in a power station heated by fossil fuel. In addition, a once-through steam generator is of simpler construction than a circulating-steam generator and therefore can be manufactured at particularly low cost. The use of a steam generator designed on the once-through principle as a waste heat steam generator of a gas and steam turbine system is therefore particularly suitable for achieving a high overall efficiency of the gas and steam turbine system combined with simple construction.
Particular advantages with regard to the cost of manufacture and also the necessary maintenance work is offered by a waste-heat steam generator of horizontal design where the heating medium or heating gas, in particular the waste gas from the gas turbine, is passed through the steam generator in an almost horizontal direction of flow. A horizontal steam generator of this kind is known from EP 0 944 801 B 1. Because of its design as a once-through steam generator, the overflowing of water from the evaporator tubes forming the continuous heating surface into the downstream superheater must be prevented during operation. However, this can cause problems, particularly when starting the steam generator.
When the steam generator is started, a water discharge, as it is called, can occur. This arises when the flow medium in the evaporator tubes initially evaporates due to the heating of the evaporator tubes and this, for example, takes place in the middle of the particular evaporator tube. This causes the quantity of water downstream (also known as water plugs) to be expelled from the particular evaporator tube. To reliably make sure that unevaporated flow medium from the evaporator tubes cannot reach the superheater connected after the tubes, the known steam generator, such as normally also a once-through steam generator of vertical design, is provided with a water-steam separator or precipitator connected between the evaporator tubes forming the continuous heating surface and the superheater. Surplus water is drawn off from this and either returned to the evaporator by a circulating pump or discharged. A water-steam separating system of this kind is, however, comparatively expensive with regard to both design and maintenance.

Method for starting a steam generator comprising a heating gas channel that can be traversed in an approximately horizontal heating gas direction and a steam generator


The disclosed computer-implemented method for identifying malicious files may include (1) identifying different instances of a file that is subject to a security evaluation, (2) identifying, within a field for each of the different instances, an attribute of the different instance that associates the different instance with a respective application, (3) determining that the respective applications to which the different instances of the file are associated are distinct applications and are known to be safe, (4) adjusting a security policy for the file, by increasing an estimation that the file is malicious, based on the determination that the respective applications are distinct applications and are known to be safe, and (5) classifying, in a software security system, the file as malicious based on the adjusted security policy that increased the estimation that the file is malicious. Various other methods, systems, and computer-readable media are also disclosed.

According to one traditional technique, security software companies may estimate that files are safe when the files are associated with valid program characteristics. Security vendors may include this technique in protocols or heuristics for detecting malware. Because safe files are frequently associated with valid program characteristics, this approach allows security vendors to efficiently determine that the files are safe. The approach also allows the security vendors to exclude the safe files from investigation beyond a cursory analysis for valid program characteristics.
Unfortunately, programmers with malevolent motives may associate malicious files with valid program characteristics to avoid detection by security vendors. As a result, these malicious files may increasingly evade detection. Accordingly, the instant disclosure identifies a need for improved methods for detecting malicious files that are disguising themselves as safe.

Systems and methods for identifying malicious files


A combination platen and sheet fed scanner has a retractable lamp which comprises a sheet fed scanning unit (1). A sheet feeding mechanism is in the sheet fed scanning unit (1). A first camera images a first side of a document fed through the sheet feeding mechanism. A second camera images a side of the document. A platen (2) is detachably mounted to the sheet fed scanning unit (1). A mechanism moves the second camera from the sheet fed scanning unit (1) to the platen (2). A lamp is associated with the second camera, the lamp is retractably mounted to the second camera.

Document scanners have become a popular computing accessory both in the home and the office. Document scanners (or simply "scanners") come in three distinct varieties: sheet fed scanners, platen scanners, and combination sheet fed with platen capability scanners. With respect to sheet fed scanners, an image forming subsystem, such as a camera, typically a charged couple device (CCD) and a lens in combination with an illumination source, scans an image by moving a sheet of paper past the camera, which sits in a stationary position. Individual raster lines are imaged by the camera and then pieced together to create a two-dimensional (2D) image representation of the original document. The camera is basically looking at one sliver of the document many times as the document is moved across a lens. The paper motion supplies one dimension of the document image, while the width is supplied by the camera. The in-paper travel direction and the width of the document is determined by the optics magnification and the dimensions of the CCD within the image forming subsystem.
In some cases, the shape of the sheet fed scanners paper path is semi-circular. For example, some scanners have a semi-circular paper path wherein sheets can be fed from a tray on top and exit beneath, or vice versa. In other cases, the paper path is "straight through."
In a platen scanner, a document is placed face down onto a stationary flat, glass surface of the scanning unit and the image forming subsystem (camera and illumination source) moves underneath the fixed document to perform the scanning operation. In this case, the camera's motion provides the length, of the scanned image, while the camera's optics provides the width.
Production scanners, also known as combination scanners, vary in speed, function, and cost and are often used by businesses for scanning large quantities of documents. For example, scans of several hundred (100) to several hundred thousand (100,000) pages per job are typical for "production" scanners. One type of production scanner combines the functionality of a sheet fed scanner with that of a platen scanner. Combination production scanners feed multiple sheets from a stack past a stationary camera, thus eliminating the need for lifting a lid and placing document sheets face down one at a time. The platen capability is employed to deal with documents that do not feed reliably from a stack. Production scanners of this type are manufactured as a single unit combining the platen scanning functions with the sheet moving functions.
In one common configuration, a dual camera image forming subsystem is used with a paper path extending between the cameras and the scanner is adapted to operate in two distinct scanning modes. In a sheet fed or straight-through scanning mode, documents are fed from a stack and between the cameras so that they are imaged on both the top and bottom during the same scanning operation. In a platen scanning mode, one of the cameras can be made to mimic the functionality of a platen scanner by placing a platen element adjacent to it and moving the camera beneath a stationary document placed on the platen. In this way, one of the "stationary" cameras is also used as part of a platen image forming subsystem as a "moving camera." Such combination production scanners are often known as platen scanners with auto feed capability. This class of scanning devices utilizes a small paper path in combination with a camera that operates in both a parked position for auto-feed with movement of a document for sheet fed scanning, and mobile operation for a stationary document during platen scanning.
Prior art sheet fed, platen, or combination scanners, have some limitations. For those customers whose primary need is for a sheet fed scanner but who occasionally need the platen utility, they must purchase a combination device or two separate scanners, one sheet fed and one platen. Purchasing both types of scanning devices may be cost prohibitive or impossible and, in either case, impractical for applications where portability is desired. For example, service bureaus require the ability to pick up the scanner and host computer, which is attached to the scanner, in order to transport both systems to the jobsite. After the job is finished, the scanner and computer must be brought back to the service bureau headquarters or to the next jobsite. Thus, portability and the ability to reconfigure and perform multiple scanning functions are critical to people who buy scanners to scan documents as a service.
Other limitations of the prior art scanners are the relatively high cost and large size of the footprint associated with the combination production scanners that combine platen and sheet feeding functions in one unit. That is, they take up significant room on a desktop. Since the footprint is large, the cost of manufacture is greater than a single function scanning device.
Typically, such combination production scanners only come in one of various classes suitable for scanning a single size or style of document. For example, the platen portion of the combination scanner can be equipped to handle 8½×11 inch or European sized documents (also known as A4) or they can be equipped to handle 11 by 17 inch documents (also known as A3). Thus, the prior art combination production scanners may not be configured to scan the size of documents that the customer desires have scanned. A relatively low cost scanning device that can handle various paper sizes in a unit having a relative small footprint, and which combines the functionality of a platen scanner with that of a sheet fed scanner would provide numerous advantages.
A problem with bottom fed sheet combination scanners, is that these paper paths include one fairly sharp angled bend. FIG. 1 depicts a typical paper path, camera and platen arrangement of the prior art. This bend is necessary in order to allow room for the lower camera 24 and it's illumination source to move out from underneath the paper path rollers 13, 14 that are located upstream of the stationary (sheet fed) scanning aperture. This occurs when the CCD camera is moved into the platen imaging portion whereby the paper is stationary and the lower camera 24 moves under the paper to form the image.
Normally, the illumination source must be located very close to the (sheet fed) scanning aperture plane. This is done in order to minimize the distance from the illumination source, or lamp, to the sheet being imaged and thereby optimize the amount of reflected light as seen by the camera. Since the camera must have the same focal position in both the stationary (sheet fed) position and the moving (platen scan position), this means that the plane at which the document passes by the camera and the plane of the platen glass are the same. Since rollers of some diameter (usually on the order of 0.750″ to 1.00″) are employed to move the sheet through the sheet fed portion of the scanner, this means that the entry point of the sheet must be greater than this diameter above the plane of the platen and/or stationary aperture. In the prior art, this is accomplished by angling the paper path downward toward the plane of the stationary aperture and then forcing the sheet to turn sharply just prior to reaching the plane of the aperture. This angle and elevation change in the paper path allows for sufficient clearance for the illumination source and the image forming device (camera) to move under these rollers and out into the platen. Normally, the platen camera moves along a rod that positions it relative to both the stationary and platen so that the illumination source clears the aperture glass planes.
This sharp bend in the paper path 62, leads to a reduced range of paper thickness and stiffness that can be fed reliably by the sheet fed transport. The bend may also impart imaging artifacts. For very stiff or very thick sheets, this turn is too sharp and can cause paper damage and/or stalling due to stubbing and/or drag forces that are too high. Image artifacts can occur as a result of sheet deformation that comes as result of the sharp bend. In addition, motion anomalies can show up as image artifacts due to momentary changes in velocity that are found as the sheet goes through the angle transitions. It is therefore desirable to provide a combination scanner with a detachable platen wherein the paper path for the sheet fed portion is not forced through a sharp bend during sheet fed scanning.

Retractable lamp for an improved document scanner paper path


A catalytic material includes (i) a support material and (ii) a thin film catalyst coating having an inner face adjacent to the support material and an outer face, the thin film catalyst coating having a mean thickness of ≦8 nm, and wherein at least 40% of the support material surface area is covered by the thin film catalyst coating; and wherein the thin film catalyst coating includes a first metal and one or more second metals, and wherein the atomic percentage of first metal in the thin film catalyst coating is not uniform through the thickness of the thin film catalyst coating.

Field of the Invention
The present invention relates to a novel catalytic material, to a catalyst layer comprising such a catalytic material and to its use as an electrode in an electrochemical device, in particular a fuel cell, such as a proton exchange membrane fuel cell.
Description of the Related Art
A fuel cell is an electrochemical cell comprising two electrodes separated by an electrolyte. A fuel, such as hydrogen or an alcohol such as methanol or ethanol, is supplied to the anode and an oxidant, such as oxygen or air, is supplied to the cathode. Electrochemical reactions occur at the electrodes, and the chemical energy of the fuel and the oxidant is converted to electrical energy and heat. Electrocatalysts are used to promote the electrochemical oxidation of the fuel at the anode and the electrochemical reduction of oxygen at the cathode.
Fuel cells are usually classified according to the nature of the electrolyte employed. Often, the electrolyte is a solid polymeric membrane, in which the membrane is electronically insulating but ionically conducting. In the proton exchange membrane fuel cell (PEMFC), the membrane is proton conducting, and protons, produced at the anode, are transported across the membrane to the cathode, where they combine with oxygen to form water. Alternatively, the electrolyte is a liquid or molten ion-conducting electrolyte, such as phosphoric acid, as used in a phosphoric acid fuel cell (PAFC).
A principal component of the PEMFC is the membrane electrode assembly (MEA) which is essentially composed of five layers. The central layer is the polymer ion-conducting membrane. On either side of the ion-conducting membrane there is an electrocatalyst layer, containing an electrocatalyst designed for the specific electrochemical reaction. Finally, adjacent to each electrocatalyst layer there is a gas diffusion layer. The gas diffusion layer must allow the reactants to reach the electrocatalyst layer and must conduct the electric current that is generated by the electrochemical reactions. Therefore the gas diffusion layer must be porous and electrically conducting.
Electrocatalysts for fuel oxidation and oxygen reduction are typically based on platinum or platinum alloyed with one or more other metals. The platinum or platinum alloy catalyst can be in the form of unsupported nanometer sized particles (such as metal blacks or other unsupported particulate metal powders) or can be deposited as even higher surface area particles onto a conductive carbon substrate, or other conductive material (to form a supported catalyst).
The MEA can be constructed by several methods. The electrocatalyst layer may be applied to the gas diffusion layer to form a gas diffusion electrode. Two gas diffusion electrodes can be placed either side of an ion-conducting membrane and laminated together to form the five-layer MEA. Alternatively, the electrocatalyst layer may be applied to both faces of the ion-conducting membrane to form a catalyst coated ion-conducting membrane. Subsequently, gas diffusion layers are applied to both faces of the catalyst coated ion-conducting membrane. Finally, an MEA can be formed from an ion-conducting membrane coated on one side with an electrocatalyst layer, a gas diffusion layer adjacent to that electrocatalyst layer, and a gas diffusion electrode on the other side of the ion-conducting membrane.
Typically tens or hundreds of MEAs are required to provide enough power for most applications, so multiple MEAs are assembled to make up a fuel cell stack. Field flow plates are used to separate the MEAs. The plates perform several functions: supplying the reactants to the MEAs, removing products, providing electrical connections and providing physical support.
Existing state of the art electrocatalysts used in fuel cells are typically made from platinum or platinum alloys supported on conducting high surface area carbon supports. The carbon allows a high surface area of platinum to be created typically in the form of discrete nano-particles of approximately spherical geometry. The carbon support also forms a porous layer such that gaseous reactants and liquid products, or liquid reactants and gaseous products, can move to and from the electrocatalytic nano-particles. In real operational conditions, particularly at the cathode of a fuel cell where the oxygen reduction reaction occurs, a number of problems arise with carbon supported catalysts including corrosion of the carbon support and dissolution and sintering of the platinum or platinum alloy catalyst particles leading to loss of performance. A further, and more important, problem with such catalysts is that the amount of platinum needed for sufficient power output from a stack is considered too high for economic application in cost critical areas such as automotive drive trains. Therefore, of particular need, are improved catalysts for the oxygen reduction reaction that takes place at the cathode of the fuel cell. Although the existing nano-particulate platinum particles supported on carbon have high platinum surface area (surface area per unit mass of platinum—m2/g) typically greater than 50 m2/g, the surface has a low intrinsic surface specific activity (activity in terms of current generated per unit area of catalyst surface—μA/cm2) when they are equal to or less than about 3 nm in diameter (M. Shao, A. Peles, K. Shoemaker, Nano Letters, 11, 3714-3719 (2011)). This results in the overall mass activity in terms of current generated per unit mass of platinum (A/mg) being lower than required. In addition, particles of this size have poor resistance to potential cycling and can both dissolve and sinter rapidly. Also typically with the state-of-the-art catalysts, a high proportion of the carbon support surface area remains uncovered which can be oxidised, causing degradation of the catalyst, at the high potentials that occur on the cathode during routine operation and at the even higher potentials that can occur during start up and shut down periods.
One of the contributions to the low surface specific activity and to the poor stability of small platinum particles is the high number of atoms in low co-ordination sites. An atom at a low co-ordination site has fewer bonds to other platinum (metal) atoms. For example, for an octahedron, the atoms at the corners have only four near neighbours (co-ordination number is 4), atoms at an edge have seven and atoms within the (111) plane have nine near neighbours. For a small octahedron, there is a higher proportion of corner and edge sites compared to a large octahedron. Atoms at low co-ordination sites are more vulnerable to dissolution because they are not as strongly bound to the solid particle. They are also able to bond more strongly to oxygen, which means it is harder to carry out the oxygen reduction reaction; the metal tends to form an oxide rather than water.
When the particles are larger than 3 nm in diameter they are more stable and have a lower proportion of low co-ordination atoms, thus having a higher specific surface activity. However, since the surface area is lower, they typically have a lower mass activity. Since only the surface of the particle can act electrocatalytically the majority of the valuable platinum metal within the particle is not used.
Alternative structures, such as the acicular structures of platinum supported on polymer fibrils as disclosed in EP 1 021 246 B1 have been proposed as suitable alternative catalysts for the oxygen reduction reaction. These catalysts can have higher specific activities than state-of-the-art nano-particulate catalysts, but because the surface area to volume ratio of the platinum structures is still low and the platinum surface areas are therefore also low (typically around 10 m2/g platinum) (Handbook of Fuel Cells—Fundamentals, Technology and Applications, Volume 3: Fuel Cell Technology and Applications, pages 576-589), the mass activity is not sufficiently improved.
Therefore, there remains the need for improved catalysts which demonstrate higher mass activity than the current designs and which are also stable to both dissolution and sintering of the platinum, and support corrosion. It is therefore the object of the present invention to provide an improved catalytic material for use in electrochemical devices, in particular a fuel cell. The catalytic material has improved mass activity over state-of-the-art catalysts. In addition, the catalytic material has improved stability to dissolution and sintering and support corrosion.

Thin film catalytic material for use in fuel


The present invention discloses and claims a series of substituted N-phenyl-bipyrrolidine carboxamides of formula (I).

1. Field of the Invention
The present invention relates to a series of substituted N-phenyl-bipyrrolidine carboxamides. The compounds of this invention are modulators of H3 receptors and are, therefore, useful as pharmaceutical agents, especially in the treatment and/or prevention of a variety of diseases modulated by H3 receptors including diseases associated with the central nervous system. Additionally, this invention also relates to methods of preparation of substituted N-phenyl-bipyrrolidine carboxamides and intermediates therefor.
2. Description of the Art
Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells, and neurons. The physiological actions of histamine are mediated by four pharmacologically defined receptors (H1, H2, H3 and H4). All histamine receptors exhibit seven transmembrane domains and are members of the G-protein-coupled receptor superfamily (GPCRs).
The H1 receptor was the first member of the histamine receptor family to be pharmacologically defined, with the development of classical antihistamines (antagonists), such as diphenhydramine and fexofenadine. While antagonism of the H1 receptor of the immune system is commonly used for the treatment of allergic reactions, the H1 receptor is also expressed in various peripheral tissues and the central nervous system (CNS). In the brain, H1 is involved in the control of wakefulness, mood, appetite and hormone secretion.
The H2 receptor is also expressed in the CNS, where it may modulate several processes, including cognition. However, H2 receptor antagonists have primarily been developed to ameliorate gastric ulcers by inhibiting histamine-mediated gastric acid secretion by parietal cells. Classic H2 antagonists include cimetidine, ranitidine, and famotidine.
It should further be noted that H4 receptor function remains poorly defined, but may involve immune regulation and inflammatory processes.
H3 receptors have also been pharmacologically identified in the CNS, heart, lung, and stomach. The H3 receptor differs significantly from other histamine receptors, exhibiting low sequence homology (H1: 22%, H2: 21%, H4: 35%). H3 is a presynaptic autoreceptor on histamine neurons in the brain and a presynaptic heteroreceptor in nonhistamine-containing neurons in both the central and peripheral nervous systems. In addition to histamine, H3 also modulates the release and/or synthesis of other neurotransmitters, including acetylcholine, dopamine, norepinepherin and serotonin. Of particular note, presynaptic modulation of histamine release by H3 allows significant regulation of H1 and H2 receptors in the brain. Modulating multiple neurotransmitter signaling pathways, H3 may contribute to varied physiological processes. Indeed, extensive preclinical evidence indicates that H3 plays a role in cognition, sleep-wake cycle and energy homeostasis.
Modulators of H3 function may be useful in the treatment of obesity and central nervous system disorders (Schizophrenia, Alzheimer's disease, attention-deficit hyperactivity disorder, Parkinson's disease, depression, and epilepsy), sleep disorders (narcolepsy and insomnia), cardiovascular disorders (acute myocardial infarction), respiratory disorders (asthma), and gastrointestinal disorders. See generally, Hancock, Biochem. Pharmacol. 2006 Apr. 14; 71(8):1103-13 and Esbenshade et al. Mol Interv. 2006 April; 6(2):77-88, 59.
Recently, compounds that are somewhat structurally related to the compounds of the present invention have been disclosed to be melanin concentrating hormone (MCH) receptor antagonists, see specifically U.S. Pat. No. 7,223,788. It should however be pointed out that there is no disclosure as to the activity of the compounds disclosed therein at the H3 receptor site.
All of the references described herein are incorporated herein by reference in their entirety.
Accordingly, it is an object of this invention to provide a series of substituted N-phenyl-bipyrrolidine carboxamides as selective H3 receptor ligands for treatment of H3 receptor regulated CNS disorders.
It is also an object of this invention to provide processes for the preparation of the substituted N-phenyl-bipyrrolidine carboxamides as disclosed herein.
Other objects and further scope of the applicability of the present invention will become apparent from the detailed description that follows.

Substituted N-phenyl-bipyrrolidine carboxamides and therapeutic use thereof

Abstract: Wherein R, R1, R2, R3 and R4 are as described herein. More specifically, the compounds of this invention are modulators of H3 receptors and are, therefore, useful as pharmaceutical agents, especially in the treatment and/or prevention of a variety of diseases modulated by H3 receptors including diseases associated with the central nervous system. Additionally, this invention also discloses methods of preparation of substituted N-phenyl-bipyrrolidine carboxamides and intermediates therefor.


An organic-inorganic hybrid composite which comprises an inorganic component and an organic conducting component. The inorganic component inhibits deprotonation of the organic conducting component when the composite is exposed to a medium having a pH which would deprotonate the organic conducting component but for the presence of the inorganic component.

1. Field of the Invention
This invention relates to electrically conductive organic-inorganic hybrid composites.
2. Description of the Related Art
Inherently conductive polymers (ICP's) are organic polymers with conjugated π-electronic structures in the polymer backbone. Examples of ICP's include polyaniline, polyacetylene, polypyrrole, polythiophene, poly(phenylene vinylene) and chemical modifications thereto. These polymers are potentially useful as additives in paint formulations that are used as protective organic primers and also have anti-electrostatic, electrostatic dispersion and electromagnetic shielding applications. ICP's can exist ill several reduced or oxidized (to a variable degree) states, all of which appear in de-protonated (base) or protonated (salt) forms. However, the various states and forms of the ICP's reversibly interconvert based upon the redox and/or acid-base characteristics of their environment.
ICP's, being reversibly oxidizable and reducible, interact with metal surfaces to inhibit corrosion. Inherently conductive forms of ICP'S, i.e. the salt forms, appear to be protective against corrosion in oxidative environments. In reductive, and specifically alkaline environments, conductive forms of ICPs, are converted to insulator forms thereby deteriorating the effectiveness of ICP's to inhibit corrosion. Consequently, the inherently conductive state of ICP's can not be preserved in alkaline environments which are typically present in atmospheric conditions thereby significantly limiting the use of ICP's in protective organic primers. Also, the conversion of the conductive forms of ICP's to the insulator forms decreases the electrical conductivity of the ICP's thereby diminishing the effectiveness of the ICP's when used as an anti-electrostatic component. Accordingly, a need exists for a conducting ICP that resists conversion to an insulating form when in the presence of alkaline environments. The present invention addresses this need.

Conductive polymer-inorganic hybrid composites

The Board of Governors for Higher Education State of Rhode Island and the Providence Plantation


A system and method for converting a page from a network into an image file suitable for assembly of or insertion into a document generated by a document creation algorithm. The system of the invention includes a browser for retrieving a page from the network. The page can be encoded as a page description language (PDL) file representative of the page. A production agent can be provided for translating the PDL file into an image file representative of the page. The image file is of a form and type suitable for assembly or incorporation into the document.

The present invention relates to document production systems, and more particularly relates to printing systems for retrieving and inserting content from a network into a document for subsequent printing by the printing system.
The advent of the 'information super highway' or Internet has rapidly increased awareness and acceptance of the Internet as a resource for acquiring content. Hence, the Internet is rapidly replacing more traditional methods for obtaining information, such as books, journals, newspapers, magazines and even television.
The Internet is typically accessed by the use of a web browser, which provides a graphical user interface on a client machine. The web browser is configured for communicating with one or more web servers. If a user wishes to obtain content from a web page at one of the web servers, the user typically initiates a series of manual steps to capture the web page and then print the web page with a suitable printer. For example, the web browser resident on the client machine can capture a web page, which is typically created using Hypertext Markup Language (HTML), and then convert the page into a page description language (PDL) file representative of the page. The PDL file is generally not a readily viewable file, but rather is intended to be sent to a printer that employs appropriate software and hardware for printing the PDL file. If the user desires to acquire multiple web pages, the user must individually capture each web page, and then forward each page individually to the printer. Each web page may include multiple text and graphic files that must each be processed prior to printing. This is a relatively time consuming and manually intensive task.
Furthermore, since the typical web page generally includes content that is frequently updated, the user may need to access and print the web page contemporaneously with the time of use. More specifically, if a user wishes to acquire the most recent content from a web page, the user typically cannot rely upon a web page printed at a prior date. Consequently, the user may need to access the web page multiple times in order to ensure that the most updated content is retrieved.

Document production system for capturing web page content


Methods and apparatus facilitate the management of input/output (I/O) subsystems in virtual I/O servers to provide appropriate quality of services (QoS). A hierarchical QoS scheme based on partitioning of network interfaces and I/O subsystems transaction types are used to classify Virtual I/O communications. This multi-tier QoS method allows virtual I/O servers to be scalable and provide appropriate QoS granularity.

Enterprises have grown increasingly reliant on computing systems to accomplish mission-critical tasks. Such computing systems are becoming increasingly complicated and operate a heterogeneous mix of application servers and input/output (I/O) subsystems. To reduce cost and increase flexibility for application servers to access available I/O subsystems, virtual I/O servers can be used to create logical separations between the application servers and I/O subsystems to make the I/O subsystems as logical resource units to application servers.
While the move to virtual I/O servers increases flexibility, it also increases the complexity of management. The virtual I/O servers must be scalable to handle a large number of application servers with wide range of quality of service (QoS) requirements. Virtual I/O communications from application servers such as file transfers are high-bandwidth, latency-tolerant, and well-structured, while virtual I/O communications for Internet Protocol (IP) telephony application servers are low-bandwidth, low-latency, and bursty. Therefore, virtual I/O servers should provide the appropriate QoS granularity to meet the end-to-end QoS requirement of individual application servers. As the ratio of application servers to I/O subsystems increases, access contention, bandwidth constraint, and other issues developed.
Aggravating the complexity of managing virtual I/O servers is the assortment of attached I/O subsystems. I/O subsystems have different capacity and traffic characteristics. I/O subsystems devices such as fibre channel storage devices operate in a coordinated data transfer manner with defined data transfer size. In the other hand, I/O subsystems such as a local area network (LAN) network interface card (NIC) tends to have bursty traffic and randomized data size. To provide end-to-end QoS guarantees, virtual I/O servers not only need to estimate the workloads, configuring, sizing, and balancing of the diverse application servers, but also the assortment of I/O subsystems, to achieve optimal performance.

Quality of service in virtual computing environments


An image pickup apparatus having difference encoding and non-linear processing of image signals includes a difference encoding circuit for quantizing a difference between signals from adjacent pixels, every other pixel, or pixels having a same color filter, in a solid-state image pickup element. A non-linear processing circuit non-linearly processes the output from the difference encoding circuit. An apparatus main body has an output terminal for supplying an output from the non-linear processing circuit, and a storage body capable of recording the output from the apparatus output terminal is coupled to the main body.

1. Field of the Invention
The present invention relates to an image pickup apparatus such as an electronic still camera.
2. Related Background Art
In recent years, an electronic still camera has been developed which A/D (analog-to-digital) converts a signal output from a solid-state image pickup element such as a CCD (charge coupled device), and stores the digital data in a detachable semiconductor memory or a rotary floppy disk, thus allowing omission of a photographic film: example, a signal from a CCD sensor 201 which has color filters shown in FIGS. 2A to 2C in units of pixels is subjected to, e.g., a CDS (Correlated-Double-Sampling) process, a blanking pulse insert process, a preknee process, and the like in an analog process unit 202, and the processed signal is then converted into, e.g., 9-bit digital data by an A/D converter 203.
If this digital data is directly stored in a semiconductor memory 205, a capacity per frame is too large, and the number of images capable of being stored in a single semiconductor memory is reduced, resulting in an inconvenient electronic still camera.
A compression process unit 204 is normally arranged to compress digital data, and the compressed data is then stored in the semiconductor memory 205. Various compression methods are known. Of these methods, DPCM (differential pulse code modulation) and DCT (discrete cosine transformation) are often adopted.
Such a prior art suffers from two problems.
The first problem lies in arrangement of the A/D converter. In order t obtain satisfactory image quality free from quantization noise, the A/D converter 203 preferably has a larger number of quantization bits. In particular, when color filters are complementary color filters, since color signals are not base-band signals but modulated signals, at least 9 bits are necessary. This leads to a complicated arrangement of the A/D converter and an increase in cost of the apparatus.
The second problem lies in the compression process unit 204. Of course, the compression process unit is preferably omitted since a circuit arrangement can be simplified. However, if data is not compressed at all, the number of images which can be stored in the semiconductor memory is considerably decreased, as described above, resulting in inconvenience. Therefore, since the compression process unit must be separately arranged, this also leads to a complicated arrangement and an increase in cost.
In an image pickup apparatus such as a color video camera, color separation filters attached to a sensor often comprise complementary color filters rather than pure color filters.
The complementary color filters are advantageous in terms of a light utilization ratio, a band, and the like as compared with pure color filters.
Many sensors having complementary color filters have been developed mainly for movie cameras. FIG. 2C shows such a filter matrix. In order to obtain a still image for one frame using this sensor, read access is required twice per pixel, and exposure must be executed twice.

Image pickup apparatus having difference encoding and non-linear processing of image signals


When executing a graphical model of a dynamic system that includes two or more concurrently executing sets of operations, a processor is configured to create a first buffer and a second buffer within the executable graphical model. A first set of operations is configured to write data to the first buffer during a first execution instance of the first set of operations. The first set of operations is configured to write data to the second buffer during a second execution instance of the first thread. A second set of operations is configured to read the data from the first buffer during an instance of the second thread that executes contemporaneously with the second execution instance of the first set of operations. Determinations regarding access to the first buffer and second buffer by the first thread and second thread are self-contained within the first thread and second thread, respectively.

A large variety of systems, such as mechanical systems, electrical systems, biological systems, and/or computer systems, may be represented as dynamic systems. Computational tools have been developed to model, simulate, and/or analyze dynamic systems. A computational tool may represent a dynamic system using a graphical model. The graphical model may include blocks that may represent components of the dynamic system. The blocks may be connected to represent relationships between the components. The computational tool may simulate the graphical model and may provide results of the simulation. One class of dynamic systems includes multi-core embedded computer systems in which sets of operations (e.g., threads, processes, etc.) may execute concurrently and utilize processing capabilities on multiple processing cores. A graphical model may be used to simulate the execution of such systems. However, developing a model for simulating multi-core systems may be challenging.
More specifically, efficient use of real-time multi-core embedded systems implies maximally concurrent execution of the two or more periodic threads of execution that make up an application. A common scenario is for the periodic threads to have an integral timing relationship (N, 2N, . . . 5N, etc.) where N is some base rate period, additionally being driven from a common timing source. Communication between these threads necessitates one of several approaches to ensure robust data sharing.
However, there are several drawbacks with conventional techniques of performing simulations of multicore, concurrent thread execution, such as the introduction of serialization of thread execution (in contrast to true concurrency), reducing hardware utilization and execution performance, and difficulties in capturing the temporal behavior of a real-time application in a modeled 'offline' simulation of the application. These difficulties lead to lower-fidelity simulations and thread synchronization for implementing the data sharing.

Data sharing in high-fidelity simulation and real-time multi-core execution


An oral composition comprises a nonionic antimicrobial or germicidal agent and at least one amphoteric surface active agent selected from the group consisting of compounds of the following general formulae (1) and (2): ##STR1## wherein R represents an alkyl group having 1 to 18 carbon atoms, and n and m are independently an integer of from 1 to 10. The composition preferably further comprises an alkyl sulfate.

1. Industrial Field
The present invention relates to an oral composition in which a nonionic antimicrobial or germicidal agent is formulated and more particularly, to an oral composition which exhibits excellent dental plaque-inhibiting and gingivitis-preventive effects by permitting the nonionic antimicrobial or germicidal agent to be stayed in the mouth over a long time.
2. Prior Art
It is known to formulate,, in oral compositions such as dentifrice, cationic germicidal effective ingredients such as chlorhexidine, cetylpyridinium chloride and the like so that formation of dental plaque is inhibited. These cationic germicides are disadvantageous in that they suffer considerable deactivation when used in the presence of surface active agents which are commonly used as a foaming agent in oral compositions. Thus, their efficacy cannot be shown satisfactorily.
On the other hand, nonionic antimicrobial or germicidal agents suffer a less degree of the deactivation with the surface active agents and show their activity to an extent in the presence of the surface active agents. Accordingly, attention has been recently paid to these agents as an effective ingredient of oral compositions. Among known nonionic antimicrobial or germicidal agents, triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) which has a very intense germicidal activity and is innoxious to human body has attracted attention because of the capability of inhibiting plaque from being formed by its intense germicidal action. In fact, there has been proposed incorporation, in oral compositions comprising triclosan, of zinc salts (Japanese Laid-open Patent Application Nos. 60-239409 and 60-239410), copper compounds (Japanese Laid-open Patent Application No. 62-89614), polyethylene glycol (Japanese Laid-open Patent Application No. 62-126116), phenolic compounds (Japanese Laid- open Patent Application No. 2-11511), and water-soluble calcium salts (Japanese Laid-open Patent Application No. 3-5416).
However, nonionic antimicrobial or germicidal agents typical of which is triclosan are very unlikely to reside in the mouth. Accordingly, known nonionic antimicrobial or germicidal agent-containing oral compositions do not show their plaque inhibiting effect satisfactorily. Hence, there is a demand for improving the above deficiency.


A safety harness for stairs including a safety belt having a first end portion adapted for adjustable coupling with a torso of a wearer. A second end portion of the safety belt is retractably coupled to a ceiling area at a top of a flight of stairs. An intermediate portion of the safety belt is secured to a wall area adjacent to the flight of stairs. The safety belt will lock when suddenly tugged on to prevent the wearer from falling.

1. Field of the Invention
The present invention relates to a safety harness for stairs and more particularly pertains to preventing a person from falling down a flight of stairs with a safety harness for stairs.
2. Description of the Prior Art
The use of fall preventing devices is known in the prior art. More specifically, fall preventing devices heretofore devised and utilized for the purpose of preventing dangerous falls are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
By way of example, U.S. Pat. No. 5,167,297 to Stevenson discloses a stairway safety and belt attachment.
U.S. Pat. No. 5,219,039 to Bell discloses a fall prevention system for billboards.
U.S. Pat. No. Des. 309,359 to Joachim discloses a child safety harness.
U.S. Pat. No. 4,709,782 to Lipinski discloses a skid-out highrise fire escape device
U.S. Pat. No. 4,334,595 to Koch discloses fall preventing devices.
U.S. Pat. No. 5,397,171 to Leach discloses a gait assistance harness apparatus.
While these devices fulfill their respective, particular objective and requirements, the aforementioned patents do not describe a safety harness for stairs for preventing a person from falling down a flight of stairs.
In this respect, the safety harness for stairs according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of preventing a person from falling down a flight of stairs.
Therefore, it can be appreciated that there exists a continuing need for new and improved safety harness for stairs which can be used for preventing a person from falling down a flight of stairs In this regard, the present invention substantially fulfills this need.