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  • Lightweight Computation of Overlaid Traffic Flows by Shortest Origin-Destination Trips

    Hiroyuki GOTO  Yohei KAKIMOTO  Yoichi SHIMAKAWA  

     
    LETTER-General Fundamentals and Boundaries

      Vol:
    E102-A No:1
      Page(s):
    320-323

    Given a network G(V,E), a lightweight method to calculate overlaid origin-destination (O-D) traffic flows on all edges is developed. Each O-D trip shall select the shortest path. While simple implementations for single-source/all-destination and all-pair trips need O(L·n) and O(L·n2) in worst-case time complexity, respectively, our technique is executed with O(m+n) and O(m+n2), where n=|V|, m=|E|, and L represents the maximum arc length. This improvement is achieved by reusing outcomes of priority queue-based algorithms. Using a GIS dataset of a road network in Tokyo, Japan, the effectiveness of our technique is confirmed.

  • On the Separating Redundancy of the Duals of First-Order Generalized Reed-Muller Codes

    Haiyang LIU  Yan LI  Lianrong MA  

     
    LETTER-Coding Theory

      Vol:
    E102-A No:1
      Page(s):
    310-315

    The separating redundancy is an important property in the analysis of the error-and-erasure decoding of a linear block code. In this work, we investigate the separating redundancy of the duals of first-order generalized Reed-Muller (GRM) codes, a class of nonbinary linear block codes that have nice algebraic properties. The dual of a first-order GRM code can be specified by two positive integers m and q and denoted by R(m,q), where q is the power of a prime number and q≠2. We determine the first separating redundancy value of R(m,q) for any m and q. We also determine the second separating redundancy values of R(m,q) for any q and m=1 and 2. For m≥3, we set up a binary integer linear programming problem, the optimum of which gives a lower bound on the second separating redundancy of R(m,q).

  • Automated Detection of Children at Risk of Chinese Handwriting Difficulties Using Handwriting Process Information: An Exploratory Study

    Zhiming WU  Tao LIN  Ming LI  

     
    PAPER-Educational Technology

      Pubricized:
    2018/10/22
      Vol:
    E102-D No:1
      Page(s):
    147-155

    Handwriting difficulties (HWDs) in children have adverse effects on their confidence and academic progress. Detecting HWDs is the first crucial step toward clinical or teaching intervention for children with HWDs. To date, how to automatically detect HWDs is still a challenge, although digitizing tablets have provided an opportunity to automatically collect handwriting process information. Especially, to our best knowledge, there is no exploration into the potential of combining machine learning algorithms and the handwriting process information to automatically detect Chinese HWDs in children. To bridge the gap, we first conducted an experiment to collect sample data and then compared the performance of five commonly used classification algorithms (Decision tree, Support Vector Machine (SVM), Artificial Neural Network, Naïve Bayesian and k-Nearest Neighbor) in detecting HWDs. The results showed that: (1) only a small proportion (13%) of children had Chinese HWDs and each classification model on the imbalanced dataset (39 children at risk of HWDs versus 261 typical children) produced the results that were better than random guesses, indicating the possibility of using classification algorithms to detect Chinese HWDs; (2) the SVM model had the best performance in detecting Chinese HWDs among the five classification models; and (3) the performance of the SVM model, especially its sensitivity, could be significantly improved by employing the Synthetic Minority Oversampling Technique to handle the class-imbalanced data. This study gains new insights into which handwriting features are predictive of Chinese HWDs in children and proposes a method that can help the clinical and educational professionals to automatically detect children at risk of Chinese HWDs.

  • Routing Topology Inference for Wireless Sensor Networks Based on Packet Tracing and Local Probing

    Xiaojuan ZHU  Yang LU  Jie ZHANG  Zhen WEI  

     
    PAPER-Network

      Pubricized:
    2018/07/19
      Vol:
    E102-B No:1
      Page(s):
    122-136

    Topological inference is the foundation of network performance analysis and optimization. Due to the difficulty of obtaining prior topology information of wireless sensor networks, we propose routing topology inference, RTI, which reconstructs the routing topology from source nodes to sink based on marking packets and probing locally. RTI is not limited to any specific routing protocol and can adapt to a dynamic and lossy networks. We select topological distance and reconstruction time to evaluate the correctness and effectiveness of RTI and then compare it with PathZip and iPath. Simulation results indicate that RTI maintains adequate reconstruction performance in dynamic and packet loss environments and provides a global routing topology view for wireless sensor networks at a lower reconstruction cost.

  • Method of Moments Based on Electric Field Integral Equation for Three-Dimensional Metallic Waveguide: Single Mode Waveguide

    Masahiro TANAKA  Kazuo TANAKA  

     
    PAPER

      Vol:
    E102-C No:1
      Page(s):
    30-37

    This paper presents the method of moments based on electric field integral equation which is capable of solving three-dimensional metallic waveguide problem with no use of another method. Metals are treated as perfectly electric conductor. The integral equation is derived in detail. In order to validate the proposed method, the numerical results are compared with those in a published paper. Three types of waveguide are considered: step discontinuity waveguide, symmetrical resonant iris waveguide, and unsymmetrical resonant iris waveguide. The numerical results are also verified by the law of conservation of energy.

  • Kirchhoff Approximation Analysis of Plane Wave Scattering by Conducting Thick Slits Open Access

    Khanh Nam NGUYEN  Hiroshi SHIRAI  

     
    PAPER

      Vol:
    E102-C No:1
      Page(s):
    12-20

    Kirchhoff approximation (KA) method has been applied for ray-mode conversion to analyze the plane wave scattering by conducting thick slits. The scattering fields can be considered as field radiations from equivalent magnetic current sources assumed by closing the aperture of the slit. The obtained results are compared with those of other methods to validate the accuracy of the proposed formulation in different conditions of slit dimension.

  • Scattering of Electromagnetic Waves by Inhomogeneous Dielectric Gratings Loaded with Conducting Strips — Matrix Formulation of Point Matching Method — Open Access

    Tsuneki YAMASAKI  

     
    PAPER

      Vol:
    E102-C No:1
      Page(s):
    3-11

    We have proposed a new method for the scattering of electromagnetic waves by inhomogeneous dielectric gratings loaded with parallel perfectly conducting strips using the combination of improved Fourier series expansion method and point matching method. Numerical results aregiven for the transmission and scattering characteristics for TE and TM cases.

  • Theoretical Analysis on Bit Error Rate of Visible-Light Variable N-Parallel Code-Shift-Keying

    Keisuke OSAWA  Hiromasa HABUCHI  Yusuke KOZAWA  

     
    PAPER-Communication Theory and Signals

      Vol:
    E101-A No:12
      Page(s):
    2352-2358

    Lighting constrained visible-light communications are expected as indoor communications of next generation. In lighting constrained visible-light communications, lighting devices are used not only for illuminating rooms but also for optical wireless communications. For lighting constrained visible-light communications, we have been proposed a variable N-parallel code-shift-keying (VN-CSK) using a modified prime sequence code (MPSC). The VN-CSK system using MPSC has not only a suppression function for reducing co-channel interference from neighboring lighting devices, but also a function for keeping constant data transmission regardless of dimming control. In this paper, the bit error rate (BER) of the VN-CSK system using MPSC is derived under an indoor visible-light communication channel by theoretical analysis. Moreover, we evaluate the BER performance for the brightness level (dimming control stage).

  • A Unified Approach to Error Exponents for Multiterminal Source Coding Systems

    Shigeaki KUZUOKA  

     
    PAPER-Shannon theory

      Vol:
    E101-A No:12
      Page(s):
    2082-2090

    Two kinds of problems - multiterminal hypothesis testing and one-to-many lossy source coding - are investigated in a unified way. It is demonstrated that a simple key idea, which is developed by Iriyama for one-to-one source coding systems, can be applied to multiterminal source coding systems. In particular, general bounds on the error exponents for multiterminal hypothesis testing and one-to-many lossy source coding are given.

  • Design and Analysis of A Low-Power High-Speed Accuracy-Controllable Approximate Multiplier

    Tongxin YANG  Tomoaki UKEZONO  Toshinori SATO  

     
    PAPER

      Vol:
    E101-A No:12
      Page(s):
    2244-2253

    Multiplication is a key fundamental function for many error-tolerant applications. Approximate multiplication is considered to be an efficient technique for trading off energy against performance and accuracy. This paper proposes an accuracy-controllable multiplier whose final product is generated by a carry-maskable adder. The proposed scheme can dynamically select the length of the carry propagation to satisfy the accuracy requirements flexibly. The partial product tree of the multiplier is approximated by the proposed tree compressor. An 8×8 multiplier design is implemented by employing the carry-maskable adder and the compressor. Compared with a conventional Wallace tree multiplier, the proposed multiplier reduced power consumption by between 47.3% and 56.2% and critical path delay by between 29.9% and 60.5%, depending on the required accuracy. Its silicon area was also 44.6% smaller. In addition, results from two image processing applications demonstrate that the quality of the processed images can be controlled by the proposed multiplier design.

  • Construction of Locally Repairable Codes with Multiple Localities Based on Encoding Polynomial

    Tomoya HAMADA  Hideki YAGI  

     
    PAPER-Coding theory and techniques

      Vol:
    E101-A No:12
      Page(s):
    2047-2054

    Locally repairable codes, which can repair erased symbols from other symbols, have attracted a good deal of attention in recent years because its local repair property is effective on distributed storage systems. (ru, δu)u∈[s]-locally repairable codes with multiple localities, which are an extension of ordinary locally repairable codes, can repair δu-1 erased symbols simultaneously from a set consisting of at most ru symbols. An upper bound on the minimum distance of these codes and a construction method of optimal codes, attaining this bound with equality, were given by Chen, Hao, and Xia. In this paper, we discuss the parameter restrictions of the existing construction, and we propose explicit constructions of optimal codes with multiple localities with relaxed restrictions based on the encoding polynomial introduced by Tamo and Barg. The proposed construction can design a code whose minimum distance is unrealizable by the existing construction.

  • Design of ELF/VLF Chirp-BOK Communication Based on Modulated Heating Low Ionosphere

    Kaijie ZHOU  Huali WANG  Peipei CAO  Zhangkai LUO  

     
    PAPER-Communication Theory and Signals

      Vol:
    E101-A No:12
      Page(s):
    2464-2471

    Excitation of Extremely Low Frequency (ELF)/Very Low Frequency (VLF) from ionosphere,which is artificial modulated by High Frequency (HF) waves can provide a way of antenna generation for deep submarine communication. In this paper, based on plasma energy conservation equation, the theoretical model of amplitude modulation HF pump heating low ionosphere for ELF/VLF generation is established. The linear frequency modulation technique of up-chirp and down-chirp have good self-correlation and cross-correlation, by which information can be transmitted by up-chirp and down-chirp. Thus, the linear frequency modulation technique can be applied to the ionosphere ELF/VLF communication. Based on this, a Chirp-BOK (Binary Orthogonal Keying) communication scheme is proposed. Indeed the Chirp-BOK amplitude and power modulation function are designed by combining the linear frequency modulation technique with the square wave amplitude modulation technique. The simulation results show in the condition that the ionosphere is heated by the Chirp-BOK power modulation HF waves, the temperature of ionospheric electronic and the variations of conductivity have obvious frequency modulation characteristics which are the same as that of power modulation, so does the variation of ionospheric current. Thus, when the ionosphere is heated by Chirp-BOK power modulation HF waves, the up-chirp (symbol ‘0’) and down-chirp (symbol ‘1’) ELF/VLF signals can be generated.

  • Multiple-Breadcrumbs: A New In-Network Guidance for Off-Path Cache in Cache Networks

    Yusaku HAYAMIZU  Miki YAMAMOTO  Elisha ROSENSWEIG  James F. KUROSE  

     
    PAPER-Network

      Pubricized:
    2018/06/22
      Vol:
    E101-B No:12
      Page(s):
    2388-2396

    In-network guidance to off-path cache, Breadcrumbs, has been proposed for cache network. It guides content requests to off-path cached contents by using the latest content download direction pointer, breadcrumbs. In Breadcrumbs, breadcrumb pointer is overwritten when a new content download of the corresponding content passes through a router. There is a possibility that slightly old guidance information for popular contents might lead to better cached content than the latest one. In this paper, we propose a new in-network guidance, Multiple-Breadcrumbs, which holds old breadcrumbs even with the latest breadcrumb pointer generated with a new content download. We focus on its content search capability and propose Throughput Sensitive selection that selects the content source giving the best estimated throughput. Our performance evaluation gives interesting results that our proposed Multiple Breadcrumbs with Throughput Sensitive selection improves not only throughput for popular contents but also for unpopular contents.

  • Parallel Precomputation with Input Value Prediction for Model Predictive Control Systems

    Satoshi KAWAKAMI  Takatsugu ONO  Toshiyuki OHTSUKA  Koji INOUE  

     
    PAPER-Real-time Systems

      Pubricized:
    2018/09/18
      Vol:
    E101-D No:12
      Page(s):
    2864-2877

    We propose a parallel precomputation method for real-time model predictive control. The key idea is to use predicted input values produced by model predictive control to solve an optimal control problem in advance. It is well known that control systems are not suitable for multi- or many-core processors because feedback-loop control systems are inherently based on sequential operations. However, since the proposed method does not rely on conventional thread-/data-level parallelism, it can be easily applied to such control systems without changing the algorithm in applications. A practical evaluation using three real-world model predictive control system simulation programs demonstrates drastic performance improvement without degrading control quality offered by the proposed method.

  • Cooperative GPGPU Scheduling for Consolidating Server Workloads

    Yusuke SUZUKI  Hiroshi YAMADA  Shinpei KATO  Kenji KONO  

     
    PAPER-Software System

      Pubricized:
    2018/08/30
      Vol:
    E101-D No:12
      Page(s):
    3019-3037

    Graphics processing units (GPUs) have become an attractive platform for general-purpose computing (GPGPU) in various domains. Making GPUs a time-multiplexing resource is a key to consolidating GPGPU applications (apps) in multi-tenant cloud platforms. However, advanced GPGPU apps pose a new challenge for consolidation. Such highly functional GPGPU apps, referred to as GPU eaters, can easily monopolize a shared GPU and starve collocated GPGPU apps. This paper presents GLoop, which is a software runtime that enables us to consolidate GPGPU apps including GPU eaters. GLoop offers an event-driven programming model, which allows GLoop-based apps to inherit the GPU eaters' high functionality while proportionally scheduling them on a shared GPU in an isolated manner. We implemented a prototype of GLoop and ported eight GPU eaters on it. The experimental results demonstrate that our prototype successfully schedules the consolidated GPGPU apps on the basis of its scheduling policy and isolates resources among them.

  • A Comparison Study on Front- and Back-of-Device Touch Input for Handheld Displays

    Liang CHEN  Dongyi CHEN  Xiao CHEN  

     
    BRIEF PAPER

      Vol:
    E101-C No:11
      Page(s):
    880-883

    Touch screen has become the mainstream manipulation technique on handheld devices. However, its innate limitations, e.g. the occlusion problem and fat finger problem, lower user experience in many use scenarios on handheld displays. Back-of-device interaction, which makes use of input units on the rear of a device for interaction, is one of the most promising approaches to address the above problems. In this paper, we present the findings of a user study in which we explored users' pointing performances in using two types of touch input on handheld devices. The results indicate that front-of-device touch input is averagely about two times as fast as back-of-device touch input but with higher error rates especially in acquiring the narrower targets. Based on the results of our study, we argue that in the premise of keeping the functionalities and layouts of current mainstream user interfaces back-of-device touch input should be treated as a supplement to front-of-device touch input rather than a replacement.

  • Transistor Characteristics of Single Crystalline C8-BTBT Grown in Coated Liquid Crystal Solution on Photo-Alignment Films

    Risa TAKEDA  Yosei SHIBATA  Takahiro ISHINABE  Hideo FUJIKAKE  

     
    BRIEF PAPER

      Vol:
    E101-C No:11
      Page(s):
    884-887

    We examined single crystal growth of benzothienobenzothiophene-based organic semiconductors by solution coating method using liquid crystal and investigated its electrical characteristics. As the results, we revealed that the averaged mobility in the saturation region reached 2.08 cm2/Vs along crystalline b-axis, and 1.08 cm2/Vs along crystalline a-axis.

  • Automatically Generating Malware Analysis Reports Using Sandbox Logs

    Bo SUN  Akinori FUJINO  Tatsuya MORI  Tao BAN  Takeshi TAKAHASHI  Daisuke INOUE  

     
    PAPER-Network Security

      Pubricized:
    2018/08/22
      Vol:
    E101-D No:11
      Page(s):
    2622-2632

    Analyzing a malware sample requires much more time and cost than creating it. To understand the behavior of a given malware sample, security analysts often make use of API call logs collected by the dynamic malware analysis tools such as a sandbox. As the amount of the log generated for a malware sample could become tremendously large, inspecting the log requires a time-consuming effort. Meanwhile, antivirus vendors usually publish malware analysis reports (vendor reports) on their websites. These malware analysis reports are the results of careful analysis done by security experts. The problem is that even though there are such analyzed examples for malware samples, associating the vendor reports with the sandbox logs is difficult. This makes security analysts not able to retrieve useful information described in vendor reports. To address this issue, we developed a system called AMAR-Generator that aims to automate the generation of malware analysis reports based on sandbox logs by making use of existing vendor reports. Aiming at a convenient assistant tool for security analysts, our system employs techniques including template matching, API behavior mapping, and malicious behavior database to produce concise human-readable reports that describe the malicious behaviors of malware programs. Through the performance evaluation, we first demonstrate that AMAR-Generator can generate human-readable reports that can be used by a security analyst as the first step of the malware analysis. We also demonstrate that AMAR-Generator can identify the malicious behaviors that are conducted by malware from the sandbox logs; the detection rates are up to 96.74%, 100%, and 74.87% on the sandbox logs collected in 2013, 2014, and 2015, respectively. We also present that it can detect malicious behaviors from unknown types of sandbox logs.

  • Theoretical Understanding of Some Conditional and Joint Biases in RC4 Stream Cipher

    Sonu JHA  Subhadeep BANIK  Takanori ISOBE  Toshihiro OHIGASHI  Santanu SARKAR  

     
    PAPER-Cryptography and Information Security

      Vol:
    E101-A No:11
      Page(s):
    1869-1879

    In this paper we present proofs for the new biases in RC4 which were experimentally found and listed out (without theoretical justifications and proofs) in a paper by Vanhoef et al. in USENIX 2015. Their purpose was to exploit the vulnerabilities of RC4 in TLS using the set of new biases found by them. We also show (and prove) new results on couple of very strong biases residing in the joint distribution of three consecutive output bytes of the RC4 stream cipher. These biases provides completely new distinguisher for RC4 taking roughly O(224) samples to distinguish streams of RC4 from a uniformly random stream. We also provide a list of new results with proofs relating to some conditional biases in the keystreams of the RC4 stream cipher.

  • Air-Writing Recognition Based on Fusion Network for Learning Spatial and Temporal Features

    Buntueng YANA  Takao ONOYE  

     
    PAPER-Neural Networks and Bioengineering

      Vol:
    E101-A No:11
      Page(s):
    1737-1744

    A fusion framework between CNN and RNN is proposed dedicatedly for air-writing recognition. By modeling the air-writing using both spatial and temporal features, the proposed network can learn more information than existing techniques. Performance of the proposed network is evaluated by using the alphabet and numeric datasets in the public database namely the 6DMG. Average accuracy of the proposed fusion network outperforms other techniques, i.e. 99.25% and 99.83% are observed in the alphabet gesture and the numeric gesture, respectively. Simplified structure of RNN is also proposed, which can attain about two folds speed-up of ordinary BLSTM network. It is also confirmed that only the distance between consecutive sampling points is enough to attain high recognition performance.

421-440hit(3578hit)