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4241-4260hit(8214hit)

  • Hardware Neural Network for a Visual Inspection System

    Seungwoo CHUN  Yoshihiro HAYAKAWA  Koji NAKAJIMA  

     
    PAPER

      Vol:
    E91-A No:4
      Page(s):
    935-942

    The visual inspection of defects in products is heavily dependent on human experience and instinct. In this situation, it is difficult to reduce the production costs and to shorten the inspection time and hence the total process time. Consequently people involved in this area desire an automatic inspection system. In this paper, we propose a hardware neural network, which is expected to provide high-speed operation for automatic inspection of products. Since neural networks can learn, this is a suitable method for self-adjustment of criteria for classification. To achieve high-speed operation, we use parallel and pipelining techniques. Furthermore, we use a piecewise linear function instead of a conventional activation function in order to save hardware resources. Consequently, our proposed hardware neural network achieved 6GCPS and 2GCUPS, which in our test sample proved to be sufficiently fast.

  • A Behavioral Synthesis Method with Special Functional Units

    Tsuyoshi SADAKATA  Yusuke MATSUNAGA  

     
    PAPER

      Vol:
    E91-A No:4
      Page(s):
    1084-1091

    This paper proposes a novel Behavioral Synthesis method that tries to reduce the number of clock cycles under clock cycle time and total functional unit area constraints using special functional units efficiently. Special functional units are designed to have shorter delay and/or smaller area than the cascaded basic functional units for specific operation patterns. For example, a Multiply-Accumulator is one of them. However, special functional units may have less flexibility for resource sharing because intermediate operation results may not be able to be obtained. Hence, almost all conventional methods can not handle special functional units efficiently for the reduction of clock cycles in practical time, especially under a tight area constraint. The proposed method makes it possible to solve module selection, scheduling, and functional unit allocation problems using special functional units in practical time with some heuristics. Experimental results show that the proposed method has achieved maximally 33% reduction of the cycles for a small application and 14% reduction for a realistic application in practical time.

  • Novel Method of Interconnect Worstcase Establishment with Statistically-Based Approaches

    Won-Young JUNG  Hyungon KIM  Yong-Ju KIM  Jae-Kyung WEE  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E91-A No:4
      Page(s):
    1177-1184

    In order for the interconnect effects due to process-induced variations to be applied to the designs in 0.13 µm and below, it is necessary to determine and characterize the realistic interconnect worstcase models with high accuracy and speed. This paper proposes new statistically-based approaches to the characterization of realistic interconnect worstcase models which take into account process-induced variations. The Effective Common Geometry (ECG) and Accumulated Maximum Probability (AMP) algorithms have been developed and implemented into the new statistical interconnect worstcase design environment. To verify this statistical interconnect worstcase design environment, the 31-stage ring oscillators are fabricated and measured with UMC 0.13 µm Logic process. The 15-stage ring oscillators are fabricated and measured with 0.18 µm standard CMOS process for investigating its flexibility in other technologies. The results show that the relative errors of the new method are less than 1.00%, which is two times more accurate than the conventional worstcase method. Furthermore, the new interconnect worstcase design environment improves optimization speed by 29.61-32.01% compared to that of the conventional worstcase optimization. The new statistical interconnect worstcase design environment accurately predicts the worstcase and bestcase corners of non-normal distribution where conventional methods cannot do well.

  • Cause Information Extraction from Financial Articles Concerning Business Performance

    Hiroyuki SAKAI  Shigeru MASUYAMA  

     
    PAPER-Knowledge Engineering

      Vol:
    E91-D No:4
      Page(s):
    959-968

    We propose a method of extracting cause information from Japanese financial articles concerning business performance. Our method acquires cause information, e.g. "(zidousya no uriage ga koutyou: Sales of cars were good)". Cause information is useful for investors in selecting companies to invest. Our method extracts cause information as a form of causal expression by using statistical information and initial clue expressions automatically. Our method can extract causal expressions without predetermined patterns or complex rules given by hand, and is expected to be applied to other tasks for acquiring phrases that have a particular meaning not limited to cause information. We compared our method with our previous one originally proposed for extracting phrases concerning traffic accident causes and experimental results showed that our new method outperforms our previous one.

  • Prediction of Fault-Prone Software Modules Using a Generic Text Discriminator

    Osamu MIZUNO  Tohru KIKUNO  

     
    PAPER-Software Engineering

      Vol:
    E91-D No:4
      Page(s):
    888-896

    This paper describes a novel approach for detecting fault-prone modules using a spam filtering technique. Fault-prone module detection in source code is important for the assurance of software quality. Most previous fault-prone detection approaches have been based on using software metrics. Such approaches, however, have difficulties in collecting the metrics and constructing mathematical models based on the metrics. Because of the increase in the need for spam e-mail detection, the spam filtering technique has progressed as a convenient and effective technique for text mining. In our approach, fault-prone modules are detected in such a way that the source code modules are considered text files and are applied to the spam filter directly. To show the applicability of our approach, we conducted experimental applications using source code repositories of Java based open source developments. The result of experiments shows that our approach can correctly predict 78% of actual fault-prone modules as fault-prone.

  • Tree-Shellability of Restricted DNFs

    Yasuhiko TAKENAGA  Nao KATOUGI  

     
    PAPER-Algorithm Theory

      Vol:
    E91-D No:4
      Page(s):
    996-1002

    A tree-shellable function is a positive Boolean function which can be represented by a binary decision tree whose number of paths from the root to a leaf labeled 1 equals the number of prime implicants. In this paper, we consider the tree-shellability of DNFs with restrictions. We show that, for read-k DNFs, the number of terms in a tree-shellable function is at most k2. We also show that, for k-DNFs, recognition of ordered tree-shellable functions is NP-complete for k=4 and tree-shellable functions can be recognized in polynomial time for constant k.

  • Identifying Stakeholders and Their Preferences about NFR by Comparing Use Case Diagrams of Several Existing Systems

    Haruhiko KAIYA  Akira OSADA  Kenji KAIJIRI  

     
    PAPER-Software Engineering

      Vol:
    E91-D No:4
      Page(s):
    897-906

    We present a method to identify stakeholders and their preferences about non-functional requirements (NFR) by using use case diagrams of existing systems. We focus on the changes about NFR because such changes help stakeholders to identify their preferences. Comparing different use case diagrams of the same domain helps us to find changes to be occurred. We utilize Goal-Question-Metrics (GQM) method for identifying variables that characterize NFR, and we can systematically represent changes about NFR using the variables. Use cases that represent system interactions help us to bridge the gap between goals and metrics (variables), and we can easily construct measurable NFR. For validating and evaluating our method, we applied our method to an application domain of Mail User Agent (MUA) system.

  • A Low-Power Instruction Issue Queue for Microprocessors

    Shingo WATANABE  Akihiro CHIYONOBU  Toshinori SATO  

     
    PAPER

      Vol:
    E91-C No:4
      Page(s):
    400-409

    Instruction issue queue is a key component which extracts instruction level parallelism (ILP) in modern out-of-order microprocessors. In order to exploit ILP for improving processor performance, instruction queue size should be increased. However, it is difficult to increase the size, since instruction queue is implemented by a content addressable memory (CAM) whose power and delay are much large. This paper introduces a low power and scalable instruction queue that replaces the CAM with a RAM. In this queue, instructions are explicitly woken up. Evaluation results show that the proposed instruction queue decreases processor performance by only 1.9% on average. Furthermore, the total energy consumption is reduced by 54% on average.

  • A Reconfigurable Functional Unit with Conditional Execution for Multi-Exit Custom Instructions

    Hamid NOORI  Farhad MEHDIPOUR  Koji INOUE  Kazuaki MURAKAMI  

     
    PAPER

      Vol:
    E91-C No:4
      Page(s):
    497-508

    Encapsulating critical computation subgraphs as application-specific instruction set extensions is an effective technique to enhance the performance of embedded processors. However, the addition of custom functional units to the base processor is required to support the execution of these custom instructions. Although automated tools have been developed to reduce the long design time needed to produce a new extensible processor for each application, short time-to-market, significant non-recurring engineering and design costs are issues. To address these concerns, we introduce an adaptive extensible processor in which custom instructions are generated and added after chip-fabrication. To support this feature, custom functional units (CFUs) are replaced by a reconfigurable functional unit (RFU). The proposed RFU is based on a matrix of functional units which is multi-cycle with the capability of conditional execution. A quantitative approach is utilized to propose an efficient architecture for the RFU and fix its constraints. To generate more effective custom instructions, they are extended over basic blocks and hence, multiple exits custom instructions are proposed. Conditional execution has been added to the RFU to support the multi-exit feature of custom instructions. Experimental results show that multi-exit custom instructions enhance the performance by an average of 67% compared to custom instructions limited to one basic block. A maximum speedup of 4.7, compared to a general embedded processor, and an average speedup of 1.85 was achieved on MiBench benchmark suite.

  • Modeling Network Intrusion Detection System Using Feature Selection and Parameters Optimization

    Dong Seong KIM  Jong Sou PARK  

     
    PAPER-Application Information Security

      Vol:
    E91-D No:4
      Page(s):
    1050-1057

    Previous approaches for modeling Intrusion Detection System (IDS) have been on twofold: improving detection model(s) in terms of (i) feature selection of audit data through wrapper and filter methods and (ii) parameters optimization of detection model design, based on classification, clustering algorithms, etc. In this paper, we present three approaches to model IDS in the context of feature selection and parameters optimization: First, we present Fusion of Genetic Algorithm (GA) and Support Vector Machines (SVM) (FuGAS), which employs combinations of GA and SVM through genetic operation and it is capable of building an optimal detection model with only selected important features and optimal parameters value. Second, we present Correlation-based Hybrid Feature Selection (CoHyFS), which utilizes a filter method in conjunction of GA for feature selection in order to reduce long training time. Third, we present Simultaneous Intrinsic Model Identification (SIMI), which adopts Random Forest (RF) and shows better intrusion detection rates and feature selection results, along with no additional computational overheads. We show the experimental results and analysis of three approaches on KDD 1999 intrusion detection datasets.

  • Performance Evaluation of Adaptive Probabilistic Search in P2P Networks

    Haoxiang ZHANG  Lin ZHANG  Xiuming SHAN  Victor O.K. LI  

     
    LETTER-Network

      Vol:
    E91-B No:4
      Page(s):
    1172-1175

    The overall performance of P2P-based file sharing applications is becoming increasingly important. Based on the Adaptive Resource-based Probabilistic Search algorithm (ARPS), which was previously proposed by the authors, a novel probabilistic search algorithm with QoS guarantees is proposed in this letter. The algorithm relies on generating functions to satisfy the user's constraints and to exploit the power-law distribution in the node degree. Simulation results demonstrate that it performs well under various P2P scenarios. The proposed algorithm provides guarantees on the search performance perceived by the user while minimizing the search cost. Furthermore, it allows different QoS levels, resulting in greater flexibility and scalability.

  • A New Caching Technique to Support Conjunctive Queries in P2P DHT

    Koji KOBATAKE  Shigeaki TAGASHIRA  Satoshi FUJITA  

     
    PAPER-Computer Systems

      Vol:
    E91-D No:4
      Page(s):
    1023-1031

    P2P DHT (Peer-to-Peer Distributed Hash Table) is one of typical techniques for realizing an efficient management of shared resources distributed over a network and a keyword search over such networks in a fully distributed manner. In this paper, we propose a new method for supporting conjunctive queries in P2P DHT. The basic idea of the proposed technique is to share a global information on past trials by conducting a local caching of search results for conjunctive queries and by registering the fact to the global DHT. Such a result caching is expected to significantly reduce the amount of transmitted data compared with conventional schemes. The effect of the proposed method is experimentally evaluated by simulation. The result of experiments indicates that by using the proposed method, the amount of returned data is reduced by 60% compared with conventional P2P DHT which does not support conjunctive queries.

  • Improving Automatic Text Classification by Integrated Feature Analysis

    Lazaro S.P. BUSAGALA  Wataru OHYAMA  Tetsushi WAKABAYASHI  Fumitaka KIMURA  

     
    PAPER-Pattern Recognition

      Vol:
    E91-D No:4
      Page(s):
    1101-1109

    Feature transformation in automatic text classification (ATC) can lead to better classification performance. Furthermore dimensionality reduction is important in ATC. Hence, feature transformation and dimensionality reduction are performed to obtain lower computational costs with improved classification performance. However, feature transformation and dimension reduction techniques have been conventionally considered in isolation. In such cases classification performance can be lower than when integrated. Therefore, we propose an integrated feature analysis approach which improves the classification performance at lower dimensionality. Moreover, we propose a multiple feature integration technique which also improves classification effectiveness.

  • Recursion Theoretic Operators for Function Complexity Classes

    Kenya UENO  

     
    PAPER-Computation and Computational Models

      Vol:
    E91-D No:4
      Page(s):
    990-995

    We characterize the gap between time and space complexity of functions by operators and completeness. First, we introduce a new notion of operators for function complexity classes based on recursive function theory and construct an operator which generates FPSPACE from FP. Then, we introduce new function classes composed of functions whose output lengths are bounded by the input length plus some constant. We characterize FP and FPSPACE by using these classes and operators. Finally, we define a new notion of completeness for FPSPACE and show a FPSPACE-complete function.

  • Instant Casting Movie Theater: The Future Cast System

    Akinobu MAEJIMA  Shuhei WEMLER  Tamotsu MACHIDA  Masao TAKEBAYASHI  Shigeo MORISHIMA  

     
    PAPER-Computer Graphics

      Vol:
    E91-D No:4
      Page(s):
    1135-1148

    We have developed a visual entertainment system called "Future Cast" which enables anyone to easily participate in a pre-recorded or pre-created film as an instant CG movie star. This system provides audiences with the amazing opportunity to join the cast of a movie in real-time. The Future Cast System can automatically perform all the processes required to make this possible, from capturing participants' facial characteristics to rendering them into the movie. Our system can also be applied to any movie created using the same production process. We conducted our first experimental trial demonstration of the Future Cast System at the Mitsui-Toshiba pavilion at the 2005 World Exposition in Aichi Japan.

  • Recalling Temporal Sequences of Patterns Using Neurons with Hysteretic Property

    Johan SVEHOLM  Yoshihiro HAYAKAWA  Koji NAKAJIMA  

     
    PAPER

      Vol:
    E91-A No:4
      Page(s):
    943-950

    Further development of a network based on the Inverse Function Delayed (ID) model which can recall temporal sequences of patterns, is proposed. Additional advantage is taken of the negative resistance region of the ID model and its hysteretic properties by widening the negative resistance region and letting the output of the ID neuron be almost instant. Calling this neuron limit ID neuron, a model with limit ID neurons connected pairwise with conventional neurons enlarges the storage capacity and increases it even further by using a weightmatrix that is calculated to guarantee the storage after transforming the sequence of patterns into a linear separation problem. The network's tolerance, or the model's ability to recall a sequence, starting in a pattern with initial distortion is also investigated and by choosing a suitable value for the output delay of the conventional neuron, the distortion is gradually reduced and finally vanishes.

  • Distributed Fair Access Point Selection for Multi-Rate IEEE 802.11 WLANs

    Huazhi GONG  Kitae NAHM  JongWon KIM  

     
    LETTER-Networks

      Vol:
    E91-D No:4
      Page(s):
    1193-1196

    In IEEE 802.11 networks, the access point (AP) selection based on the strongest signal strength often results in the extremely unfair bandwidth allocation among mobile users (MUs). In this paper, we propose a distributed AP selection algorithm to achieve a fair bandwidth allocation for MUs. The proposed algorithm gradually balances the AP loads based on max-min fairness for the available multiple bit rate choices in a distributed manner. We analyze the stability and overhead of the proposed algorithm, and show the improvement of the fairness via computer simulation.

  • Noninvasive Femur Bone Volume Estimation Based on X-Ray Attenuation of a Single Radiographic Image and Medical Knowledge

    Supaporn KIATTISIN  Kosin CHAMNONGTHAI  

     
    PAPER-Biological Engineering

      Vol:
    E91-D No:4
      Page(s):
    1176-1184

    Bone Mineral Density (BMD) is an indicator of osteoporosis that is an increasingly serious disease, particularly for the elderly. To calculate BMD, we need to measure the volume of the femur in a noninvasive way. In this paper, we propose a noninvasive bone volume measurement method using x-ray attenuation on radiography and medical knowledge. The absolute thickness at one reference pixel and the relative thickness at all pixels of the bone in the x-ray image are used to calculate the volume and the BMD. First, the absolute bone thickness of one particular pixel is estimated by the known geometric shape of a specific bone part as medical knowledge. The relative bone thicknesses of all pixels are then calculated by x-ray attenuation of each pixel. Finally, given the absolute bone thickness of the reference pixel, the absolute bone thickness of all pixels is mapped. To evaluate the performance of the proposed method, experiments on 300 subjects were performed. We found that the method provides good estimations of real BMD values of femur bone. Estimates shows a high linear correlation of 0.96 between the volume Bone Mineral Density (vBMD) of CT-SCAN and computed vBMD (all P<0.001). The BMD results reveal 3.23% difference in volume from the BMD of CT-SCAN.

  • Joint Receive Antenna Selection for Multi-User MIMO Systems with Vector Precoding

    Wei MIAO  Yunzhou LI  Shidong ZHOU  Jing WANG  Xibin XU  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E91-B No:4
      Page(s):
    1176-1179

    Vector precoding is a nonlinear broadcast precoding scheme in the downlink of multi-user MIMO systems which outperforms linear precoding and THP (Tomlinson-Harashima Precoding). This letter discusses the problem of joint receive antenna selection in the multi-user MIMO downlink with vector precoding. Based on random matrix analysis, we derive a simple heuristic selection criterion using singular value decomposition (SVD) and carry out an exhaustive search to determine for each user which receive antenna should be used. Simulation results reveal that receive antenna selection using our proposed criterion obtains the same diversity order as the optimal selection criterion.

  • A Design of Constant-Charge-Injection Programming Scheme for AG-AND Flash Memories Using Array-Level Analytical Model

    Shinya KAJIYAMA  Ken'ichiro SONODA  Kazuo OTSUGA  Hideaki KURATA  Kiyoshi ISHIKAWA  

     
    PAPER

      Vol:
    E91-C No:4
      Page(s):
    526-533

    A design methodology optimizing constant-charge-injection programming (CCIP) for assist-gate (AG)-AND flash memories is proposed. Transient circuit simulations using an array-level model including lucky electron model (LEM) current source describing hot electron physics enables a concept design over the whole memory-string in advance of wafer manufacturing. The dynamic programming behaviors of various CCIP sequences, obtained by circuit simulations using the model is verified with the measurement results of 90-nm AG-AND flash memory, and we confirmed that the simulation results sufficiently agree with the measurement, considering the simulation results give optimum bias AG voltage approximately within 0.2 V error. Then, we have applied the model to a conceptual design and have obtained optimum bit line capacitance value and CCIP sequence those are the most important issues involved in high-throughput programming for an AG-AND array.

4241-4260hit(8214hit)