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741-760hit(3578hit)

  • Node-to-Set Disjoint Paths Problem in a Möbius Cube

    David KOCIK  Yuki HIRAI  Keiichi KANEKO  

     
    PAPER-Dependable Computing

      Pubricized:
    2015/12/14
      Vol:
    E99-D No:3
      Page(s):
    708-713

    This paper proposes an algorithm that solves the node-to-set disjoint paths problem in an n-Möbius cube in polynomial-order time of n. It also gives a proof of correctness of the algorithm as well as estimating the time complexity, O(n4), and the maximum path length, 2n-1. A computer experiment is conducted for n=1,2,...,31 to measure the average performance of the algorithm. The results show that the average time complexity is gradually approaching to O(n3) and that the maximum path lengths cannot be attained easily over the range of n in the experiment.

  • The Current State of Digital Healthcare towards Medical Application Open Access

    Toru WATSUJI  

     
    INVITED PAPER

      Vol:
    E99-B No:3
      Page(s):
    565-568

    Infrastructures for the evaluation of the state of health of individuals using a standardized communication network consisting of advanced instruments and subsequent data analysis have been developed. Here we report that this developed infrastructure has been tested in the field in 100 houses and involving almost 300 users. The communication protocol part of this infrastructure has been standardized as IEEE 11073-20601. Continua Health Alliance, an international not-for-profit industry organization which has nearly 230 member companies, has adopted this IEEE 11073-20601 to establish an ecosystem of interoperable personal connected health systems that empower individuals and organizations to better manage their health and wellness. Currently nearly 100 Continua certified products are available in public including smartphone.

  • An Area-Efficient Scalable Test Module to Support Low Pin-Count Testing

    Tong-Yu HSIEH  Tai-Ping WANG  Shuo YANG  Chin-An HSU  Yi-Lung LIN  

     
    PAPER-Electronic Circuits

      Vol:
    E99-C No:3
      Page(s):
    404-414

    Low pin-count testing is an effective method to reduce test cost. Based on this method multi-site testing, i.e., where multiple devices are tested concurrently, can be supported under the limitation on the number of channels provided by ATE. In this work we propose a scalable test module (called STM) design that can support multi-site testing more efficiently when compared with previous work. In the previous work, the total number of devices that can be tested concurrently is usually fixed when the design for testability hardware is designed. For our STM, each STM can deal with a number of circuits to be tested at the same time. Moreover, STM is scalable, i.e., multiple STMs can work collaboratively while the ATE bandwidth still remains the same to further increase the degree of test parallelism. Our STM will be integrated with ATE and serve as an interface between ATE and circuits under test (CUT). Only four pins are required by STM to communicate with ATE, and IEEE 1149.1 Std. ports are employed to transfer test data to/from CUTs. STM has been verified via silicon proof, which contains only about 2,768 logic gates. Experiments results for a number of ISCAS and IWLS'05 benchmark circuits also demonstrate that by making good use of the scalable feature of STM, test efficiency can be enhanced significantly.

  • Two-Way Cognitive DF Relaying in WSNs with Practical RF Energy Harvesting Node

    Dang Khoa NGUYEN  Hiroshi OCHI  

     
    PAPER-Network

      Vol:
    E99-B No:3
      Page(s):
    675-684

    This work presents the exact outage performance and throughput of two-way cognitive decode-and-forward relaying wireless sensor networks with realistic transceiver relay. The relay is a self-powered wireless node that harvests radio frequency energy from the transmitted signals. We consider four configurations of a network with formed by combining two bidirectional relaying protocols (multiple access broadcast protocol and time division broadcast protocol), and two power transfer policies (dual-source energy transfer and single-fixed-source energy transfer). Based on our analysis, we provide practical insights into the impact of transceiver hardware impairments on the network performance, such as the fundamental capacity ceiling of the network with various configurations that cannot be exceeded by increasing transmit power given a fixed transmission rate and the transceiver selection strategy for the network nodes that can optimize the implementation cost and performance tradeoff.

  • Decoding of Projective Reed-Muller Codes by Dividing a Projective Space into Affine Spaces

    Norihiro NAKASHIMA  Hajime MATSUI  

     
    PAPER-Coding Theory

      Vol:
    E99-A No:3
      Page(s):
    733-741

    A projective Reed-Muller (PRM) code, obtained by modifying a Reed-Muller code with respect to a projective space, is a doubly extended Reed-Solomon code when the dimension of the related projective space is equal to 1. The minimum distance and the dual code of a PRM code are known, and some decoding examples have been presented for low-dimensional projective spaces. In this study, we construct a decoding algorithm for all PRM codes by dividing a projective space into a union of affine spaces. In addition, we determine the computational complexity and the number of correctable errors of our algorithm. Finally, we compare the codeword error rate of our algorithm with that of the minimum distance decoding.

  • Novel Reconfigurable Hardware Accelerator for Protein Sequence Alignment Using Smith-Waterman Algorithm

    Atef IBRAHIM  Hamed ELSIMARY  Abdullah ALJUMAH  

     
    PAPER-Digital Signal Processing

      Vol:
    E99-A No:3
      Page(s):
    683-690

    This paper presents novel reconfigurable semi-systolic array architecture for the Smith-Waterman with an affine gap penalty algorithm to align protein sequences optimized for shorter database sequences. This architecture has been modified to enable hardware reuse rather than replicating processing elements of the semi-systolic array in multiple FPGAs. The proposed hardware architecture and the previously published conventional one are described at the Register Transfer Level (RTL) using VHDL language and implemented using the FPGA technology. The results show that the proposed design has significant higher normalized speedup (up to 125%) over the conventional one for query sequence lengths less than 512 residues. According to the UniProtKB/TrEMBL protein database (release 2015_05) statistics, the largest number of sequences (about 80%) have sequence length less than 512 residues that makes the proposed design outperforms the conventional one in terms of speed and area in this sequence lengths range.

  • Efficient Geometric Routing in Large-Scale Complex Networks with Low-Cost Node Design

    Sahel SAHHAF  Wouter TAVERNIER  Didier COLLE  Mario PICKAVET  Piet DEMEESTER  

     
    PAPER-Network

      Vol:
    E99-B No:3
      Page(s):
    666-674

    The growth of the size of the routing tables limits the scalability of the conventional IP routing. As scalable routing schemes for large-scale networks are highly demanded, this paper proposes and evaluates an efficient geometric routing scheme and related low-cost node design applicable to large-scale networks. The approach guarantees that greedy forwarding on derived coordinates will result in successful packet delivery to every destination in the network by relying on coordinates deduced from a spanning tree of the network. The efficiency of the proposed scheme is measured in terms of routing quality (stretch) and size of the coordinates. The cost of the proposed router is quantified in terms of area complexity of the hardware design and all the evaluations involve comparison with a state-of-the-art approach with virtual coordinates in the hyperbolic plane. Extensive simulations assess the proposal in large topologies consisting of up to 100K nodes. Experiments show that the scheme has stretch properties comparable to geometric routing in the hyperbolic plane, while enabling a more efficient hardware design, and scaling considerably better in terms of storage requirements for coordinate representation. These attractive properties make the scheme promising for routing in large networks.

  • Robust Face Alignment with Random Forest: Analysis of Initialization, Landmarks Regression, and Shape Regularization Methods

    Chun Fui LIEW  Takehisa YAIRI  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2015/10/27
      Vol:
    E99-D No:2
      Page(s):
    496-504

    Random forest regressor has recently been proposed as a local landmark estimator in the face alignment problem. It has been shown that random forest regressor can achieve accurate, fast, and robust performance when coupled with a global face-shape regularizer. In this paper, we extend this approach and propose a new Local Forest Classification and Regression (LFCR) framework in order to handle face images with large yaw angles. Specifically, the LFCR has an additional classification step prior to the regression step. Our experiment results show that this additional classification step is useful in rejecting outliers prior to the regression step, thus improving the face alignment results. We also analyze each system component through detailed experiments. In addition to the selection of feature descriptors and several important tuning parameters of the random forest regressor, we examine different initialization and shape regularization processes. We compare our best outcomes to the state-of-the-art system and show that our method outperforms other parametric shape-fitting approaches.

  • Analog and Digital Collaborative Design Techniques for Wireless SoCs

    Ryuichi FUJIMOTO  

     
    INVITED PAPER

      Vol:
    E99-A No:2
      Page(s):
    514-522

    Analog and digital collaborative design techniques for wireless SoCs are reviewed in this paper. In wireless SoCs, delicate analog performance such as sensitivity of the receiver is easily degraded due to interferences from digital circuit blocks. On the other hand, an analog performance such as distortion is strongly compensated by digital assist techniques with low power consumption. In this paper, a sensitivity recovery technique using the analog and digital collaborative design, and digital assist techniques to achieve low-power and high-performance analog circuits are presented. Such analog and digital collaborative design is indispensable for wireless SoCs.

  • Monitoring Temporal Properties Using Interval Analysis

    Daisuke ISHII  Naoki YONEZAKI  Alexandre GOLDSZTEJN  

     
    INVITED PAPER

      Vol:
    E99-A No:2
      Page(s):
    442-453

    Verification of temporal logic properties plays a crucial role in proving the desired behaviors of continuous systems. In this paper, we propose an interval method that verifies the properties described by a bounded signal temporal logic. We relax the problem so that if the verification process cannot succeed at the prescribed precision, it outputs an inconclusive result. The problem is solved by an efficient and rigorous monitoring algorithm. This algorithm performs a forward simulation of a continuous-time dynamical system, detects a set of time intervals in which the atomic propositions hold, and validates the property by propagating the time intervals. In each step, the continuous state at a certain time is enclosed by an interval vector that is proven to contain a unique solution. We experimentally demonstrate the utility of the proposed method in formal analysis of nonlinear and complex continuous systems.

  • Towards Route Dynamics in AS-Level Path Prediction

    Shen SU  Binxing FANG  

     
    PAPER-Internet

      Vol:
    E99-B No:2
      Page(s):
    412-421

    Predicting the routing paths between any given pair of Autonomous Systems (ASes) is very useful in network diagnosis, traffic engineering, and protocol analysis. Existing methods address this problem by resolving the best path with a snapshot of BGP (Border Gateway Protocol) routing tables. However, due to route deficiencies, routing policy changes, and other causes, the best path changes over time. Consequently, existing methods for path prediction fail to capture route dynamics. To predict AS-level paths in dynamic scenarios (e.g. network failures), we propose a per-neighbor path ranking model based on how long the paths have been used, and apply this routing model to extract each AS's route choice configurations for the paths observed in BGP data. With route choice configurations to multiple paths, we are able to predict the path in case of multiple network scenarios. We further build the model with strict policies to ensure our model's routing convergence; formally prove that it converges; and discuss the path prediction capturing routing dynamics by disabling links. By evaluating the consistency between our model's routing and the actually observed paths, we show that our model outperforms the state-of-the-art work [4].

  • Distributed and Scalable Directory Service in a Parallel File System

    Lixin WANG  Yutong LU  Wei ZHANG  Yan LEI  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2015/10/26
      Vol:
    E99-D No:2
      Page(s):
    313-323

    One of the patterns that the design of parallel file systems has to solve stems from the difficulty of handling the metadata-intensive I/O generated by parallel applications accessing a single large directory. We demonstrate a middleware design called SFS to support existing parallel file systems for distributed and scalable directory service. SFS distributes directory entries over data servers instead of metadata servers to offer increased scalability and performance. Firstly, SFS exploits an adaptive directory partitioning based on extendible hashing to support concurrent and unsynchronized partition splitting. Secondly, SFS describes an optimization based on recursive split-ordering that emphasizes speeding up the splitting process. Thirdly, SFS applies a write-optimized index structure to convert slow, small, random metadata updates into fast, large, sequential writes. Finally, SFS gracefully tolerates stale mapping at the clients while maintaining the correctness and consistency of the system. Our performance results on a cluster of 32-servers show our implementation can deliver more than 250,000 file creations per second on average.

  • k-Degree Layer-Wise Network for Geo-Distributed Computing between Cloud and IoT

    Yiqiang SHENG  Jinlin WANG  Haojiang DENG  Chaopeng LI  

     
    PAPER

      Vol:
    E99-B No:2
      Page(s):
    307-314

    In this paper, we propose a novel architecture for a deep learning system, named k-degree layer-wise network, to realize efficient geo-distributed computing between Cloud and Internet of Things (IoT). The geo-distributed computing extends Cloud to the geographical verge of the network in the neighbor of IoT. The basic ideas of the proposal include a k-degree constraint and a layer-wise constraint. The k-degree constraint is defined such that the degree of each vertex on the h-th layer is exactly k(h) to extend the existing deep belief networks and control the communication cost. The layer-wise constraint is defined such that the layer-wise degrees are monotonically decreasing in positive direction to gradually reduce the dimension of data. We prove the k-degree layer-wise network is sparse, while a typical deep neural network is dense. In an evaluation on the M-distributed MNIST database, the proposal is superior to a state-of-the-art model in terms of communication cost and learning time with scalability.

  • Threshold-Based Distributed Continuous Top-k Query Processing for Minimizing Communication Overhead

    Kamalas UDOMLAMLERT  Takahiro HARA  Shojiro NISHIO  

     
    PAPER-Data Engineering, Web Information Systems

      Pubricized:
    2015/11/11
      Vol:
    E99-D No:2
      Page(s):
    383-396

    In this paper, we propose a communication-efficient top-k continuous query processing method on distributed local nodes where data are horizontally partitioned. A designated coordinator server takes the role of issuing queries from users to local nodes and delivering the results to users. The final results are requested via a top-k subscription which lets local nodes know which data and updates need to be returned to users. Our proposed method makes use of the active previously posed queries to identify a small set of needed top-k subscriptions. In addition, with the pre-indexed nodes' skylines, the number of local nodes to be subscribed can be significantly reduced. As a result, only a small number of subscriptions are informed to a small number of local nodes resulting in lower communication overhead. Furthermore, according to dynamic data updates, we also propose a method that prevents nodes from reporting needless updates and also maintenance procedures to preserve the consistency. The results of experiments that measure the volume of transferred data show that our proposed method significantly outperforms the previously proposed methods.

  • Integrated Photonic Devices and Applications for 100GbE-and-Beyond Datacom Open Access

    Yoshiyuki DOI  Takaharu OHYAMA  Toshihide YOSHIMATSU  Tetsuichiro OHNO  Yasuhiko NAKANISHI  Shunichi SOMA  Hiroshi YAMAZAKI  Manabu OGUMA  Toshikazu HASHIMOTO  Hiroaki SANJOH  

     
    INVITED PAPER

      Vol:
    E99-C No:2
      Page(s):
    157-164

    We review recent progress in integrated photonics devices and their applications for datacom. In addition to current technology used in 100-Gigabit Ethernet (100GbE) with a compact form-factor of the transceiver, the next generation of technology for 400GbE seeks a larger number of wavelengths with a more sophisticated modulation format and higher bit rate per wavelength. For wavelength scalability and functionality, planar lightwave circuits (PLCs), such as arrayed waveguide gratings (AWGs), will be important, as well higher-order-modulation to ramp up the total bit rate per wavelength. We introduce integration technology for a 100GbE optical sub-assembly that has a 4λ x 25-Gb/s non-return-to-zero (NRZ) modulation format. For beyond 100GbE, we also discuss applications of 100GbE sub-assemblies that provide 400-Gb/s throughput with 16λ x 25-Gb/s NRZ and bidirectional 8λ x 50-Gb/s four-level pulse amplitude modulation (PAM4) using PLC cyclic AWGs.

  • GRMR: Greedy Regional Multicast Routing for Wireless Sensor Networks

    Shimin SUN  Li HAN  Sunyoung HAN  

     
    PAPER

      Pubricized:
    2015/10/21
      Vol:
    E99-D No:1
      Page(s):
    21-29

    Information Centric Networking (ICN) is a promising architecture as an alternative paradigm to traditional IP networking. The innovative concepts, such as named data, name-based routing, and in-network caching bring lots of benefits to Wireless Sensor Networks (WSNs). Simple and robust communication model of ICN, based on interest/data messages exchange, is appealing to be deployed in WSNs. However, ICN architectures are designed for power supplied network devices rather than resource-constrained sensor nodes. Introducing ICN-liked architecture to WSNs needs to rethink the naming scheme and forwarding strategy to meet the requirements of energy efficiency and failure recovery. This paper presents a light weight data centric routing mechanism (GRMR) for interest dissemination and data delivery in location-aware WSNs. A simple naming scheme gives assistance for routing decision by individual nodes. Greedy routing engaging with regional multicast mechanism provides an efficient data centric routing approach. The performance is analytically evaluated and simulated in NS-2. The results indicate that GRMR achieves significant energy efficiency under investigated scenarios.

  • Cooperative Distributed STBC Transmission Scheme for Multi-Hop V2V Communications

    Cong-Hoang DIEM  Koya SATO  Takeo FUJII  

     
    PAPER

      Vol:
    E99-A No:1
      Page(s):
    252-262

    This paper proposes a novel cooperative scheme combining distributed space-time block code (STBC) at physical layer, multiple access protocol at medium access control (MAC) layer and opportunistic routing without complicated routing algorithm for achieving high reliability for vehicle-to-vehicle (V2V) communications. The proposed scheme can reduce interference and collision, and achieve reducing redundant broadcast of safety-related messages for multi-hop vehicular communications on highway. In particular, we propose a novel algorithm of relay selection based-on position, speed and direction of movement to select intermediate vehicle stations (VS) with high contribution according to the transmission direction. Furthermore, in order to reduce interference and collision, we install a new timer to select a master relay vehicle station (MVS) which manages a packet transmission of whole network to trigger and synchronize transmitting timing of relay VSs (RVSs) in each hop. From the results of simulations, we can confirm that the proposed method can achieve reducing the redundant broadcast safety-related messages with keeping the packet loss probability by limiting the retransmission at each VS.

  • Electromagnetic Plane Wave Diffraction by Loaded N-Slits on Thick Conducting Screen

    Ryoichi SATO  Hiroshi SHIRAI  

     
    BRIEF PAPER

      Vol:
    E99-C No:1
      Page(s):
    72-75

    In this paper, an electromagnetic plane wave diffraction by finite number of loaded thick slits on infinitely long perfectly electric conductor (PEC) screen is analyzed. Here we formulate the problem by utilizing the Kobayashi Potential (KP) method, which is a kind of eigenfunction expansion method in terns of Weber-Schafheitlin discontinuous integrals. The multiple scattering contributions between the slits are analytically included in the formulation. The solution derived here may provide us with precise numerical result, so it may be considered as a reference solution to other numerical and approximate analyses.

  • Azimuth Variable-Path Loss Fitting with Received Signal Power Data for White Space Boundary Estimation

    Kenshi HORIHATA  Issei KANNO  Akio HASEGAWA  Toshiyuki MAEYAMA  Yoshio TAKEUCHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E99-B No:1
      Page(s):
    87-94

    This paper shows accuracy of using azimuth-variable path-loss fitting in white-space (WS) boundary-estimation. We perform experiments to evaluate this method, and demonstrate that the required number of sensors can be significantly reduced. We have proposed a WS boundary-estimation framework that utilizes sensors to not only obtain spectrum sensing data, but also to estimate the boundaries of the incumbent radio system (IRS) coverage. The framework utilizes the transmitter position information and pathloss fitting. The pathloss fitting describes the IRS coverage by approximating the well-known pathloss prediction formula from the received signal power data, which is measured using sensors, and sensor-transmitter separation distances. To enhance its accuracy, we have further proposed a pathloss-fitting method that employs azimuth variables to reflect the azimuth dependency of the IRS coverage, including the antenna directivity of the transmitter and propagation characteristics.

  • Indoor Positioning Based on Fingerprinting Method by Incoming GPS Signals

    Masayuki OCHIAI  Hiroyuki HATANO  Masahiro FUJII  Atsushi ITO  Yu WATANABE  

     
    LETTER

      Vol:
    E99-A No:1
      Page(s):
    319-322

    Incoming GPS signals through windows can be often observed indoors. However, conventional indoor positioning systems do not use Global Positioning System (GPS) generally because the signals may come in NLOS (Non Line of Sight). In this paper, we propose a positioning method by fingerprinting based on the incoming GPS signals.

741-760hit(3578hit)