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11221-11240hit(18690hit)

  • Signal Mappings of 8-Ary Constellations for BICM-ID Systems over a Rayleigh Fading Channel

    Nghi H. TRAN  Ha H. NGUYEN  

     
    LETTER-Fundamental Theories for Communications

      Vol:
    E88-B No:10
      Page(s):
    4083-4086

    It is known that in a bit-interleaved coded-modulation with iterative decoding (BICM-ID), signal constellation and mapping strongly influence the system's error performance. This letter presents good mappings of various 8-ary constellations for BICM-ID systems operating over a frequency non-selective block Rayleigh fading channel. Simulation results for the error performance of different constellations/mappings are also provided and discussed.

  • New Binary Constant Weight Codes Based on Cayley Graphs of Groups and Their Decoding Methods

    Jun IMAI  Yoshinao SHIRAKI  

     
    PAPER-Coding Theory

      Vol:
    E88-A No:10
      Page(s):
    2734-2744

    We propose a new class of binary nonlinear codes of constant weights derived from a permutation representation of a group that is given by a combinatorial definition such as Cayley graphs of a group. These codes are constructed by the following direct interpretation method from a group: (1) take one discrete group whose elements are defined by generators and their relations, such as those in the form of Cayley graphs; and (2) embedding the group into a binary space using some of their permutation representations by providing the generators with realization of permutations of some terms. The proposed codes are endowed with some good characteristics as follows: (a) we can easily learn information about the distances of the obtained codes, and moreover, (b) we can establish a decoding method for them that can correct random errors whose distances from code words are less than half of the minimum distances achieved using only parity checking procedures.

  • Priority-Based Optimized Bandwidth Reservation for Efficient Differentiated Services in Ethernet-PON

    NamUk KIM  Minho KANG  

     
    PAPER

      Vol:
    E88-B No:10
      Page(s):
    3962-3970

    In this paper, we address how to efficiently support differentiated services with the optimized bandwidth reservation in a polling-based generalized TDMA network like E-PON (Ethernet Passive Optical Network). In E-PON, performances of service differentiation for QoS (Quality of Service) guaranteed multiples services are directly affected by the bandwidth reservation algorithm of ONU (Optical Network Unit) in addition to the priority-based packet scheduling. Our proposed Service Quality Pre-engagement (SQP) algorithm reduces the system buffer size, the light-load penalty problem and the service interference among classes effectively by partially introducing the dynamic forward recurrence reservation scheme for QoS guaranteed classes. We also introduce the FRC(Forward Reservation Class) Selection algorithm that preserves the optimized reservation bandwidth to minimize the unnecessary reservation contentions. These algorithms do not mandate the basic concept of DBA and request the similar amount of REPORT bandwidth. The analytic and simulation results are performed to evaluate the performances of the proposed algorithms.

  • Filtering of Block Motion Vectors for Use in Motion-Based Video Indexing and Retrieval

    Golam SORWAR  Manzur MURSHED  Laurence DOOLEY  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2593-2599

    Though block-based motion estimation techniques are primarily designed for video coding applications, they are increasingly being used in other video analysis applications due to their simplicity and ease of implementation. The major drawback associated with these techniques is that noises, in the form of false motion vectors, cannot be avoided while capturing block motion vectors. Similar noises may further be introduced when the technique of global motion compensation is applied to obtain true object motion from video sequences where both the camera and object motions are present. This paper presents a new technique for capturing large number of true object motion vectors by eliminating the false motion vector fields, for use in the application of object motion based video indexing and retrieval applications. Experimental results prove that our proposed technique significantly increases the percentage of retained true object motion vectors while eliminating all false motion vectors for variety of standard and non-standard video sequences.

  • Evaluation of Partial File Modification for Java-Based Realtime Communication Systems

    Tetsuyasu YAMADA  Hiroshi SUNAGA  Shinji TANAKA  Satoshi SHIRAISHI  Keiichi KOYANAGI  

     
    PAPER-Switching for Communications

      Vol:
    E88-B No:10
      Page(s):
    3982-3991

    This paper proposes a Java online plug-in mechanism that can be used to modify any part in a system file coded in Java, even while the part is running, without service interruption. The Java-related plug-in capabilities are devised by using the plug-in functional elements offered by the existing C++ online plug-in that we proposed. In particular, measures on how to deal with the use of Just In Time compilation and inline expansion are considered. New linkage and file-back up techniques are proposed for this purpose. Case studies reveal its wide applicability and the degree of memory area saving effects. Evaluation proves this mechanism does not affect the performance of ordinary service processing. It is expected to be used in practice for Java-based service processing such as VoIP and Instant Messaging.

  • Discretized Markov Transformations--An Example of Ultradiscrete Dynamical Systems--

    Hiroshi FUJISAKI  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2684-2691

    We define discretized Markov transformations and find an algorithm to give the number of maximal-period sequences based on discretized Markov transformations. In this report, we focus on the discretized dyadic transformations and the discretized golden mean transformations. Then we find an algorithm to give the number of maximal-period sequences based on these discretized transformations. Moreover, we define a number-theoretic function related to the numbers of maximal-period sequences based on these discretized transformations. We also introduce the entropy of the maximal-period sequences based on these discretized transformations.

  • Statistical Optimization for 3-D Reconstruction from a Single View

    Kenichi KANATANI  Yasuyuki SUGAYA  

     
    PAPER

      Vol:
    E88-D No:10
      Page(s):
    2260-2268

    We analyze the noise sensitivity of the focal length computation, the principal point estimation, and the orthogonality enforcement for single-view 3-D reconstruction based on vanishing points and orthogonality. We point out that due to the nonlinearity of the problem the standard statistical optimization is not very effective. We present a practical compromise for avoiding the computational failure and preserving high accuracy, allowing a consistent 3-D shape in the presence of however large noise.

  • A Generalized KdV-Family with Variable Coefficients in (2 + 1) Dimensions

    Tadashi KOBAYASHI  Kouichi TODA  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2548-2553

    Variable-coefficient generalizations of integrable nonlinear equations are one of exciting subjects in the study of mechanical, physical, mathematical and engineering sciences. In this paper, we present a KdV family (namely, KdV, modified KdV, Calogero-Degasperis-Fokas and Harry-Dym equations) with variable coefficients in (2 + 1) dimensions.

  • An Efficient Optimization of Network Resource Allocations under Nonlinear Quality of Service Constraints

    Hakim BADIS  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2642-2646

    We present an efficient method to optimize network resource allocations under nonlinear Quality of Service (QoS) constraints. We first propose a suite of generalized proportional allocation schemes that can be obtained by minimizing the information-theoretic function of relative entropy. We then optimize over the allocation parameters, which are usually design variables an engineer can directly vary, either for a particular user or for the worst-case user, under constraints that lower bound the allocated resources for all other users. Despite the nonlinearity in the objective and constraints, we show this suite of resource allocation optimization can be efficiently solved for global optimality through a convex optimization technique called geometric programming. This general method and its extensions are applicable to a wide array of resource allocation problems, including processor sharing, congestion control, admission control, and wireless network power control.

  • Simulation Probability Density Function Design for Turbo Codes

    Takakazu SAKAI  

     
    PAPER-Coding Theory

      Vol:
    E88-A No:10
      Page(s):
    2715-2720

    We research on an importance sampling (IS) simulation to estimate a low error probability of turbo codes. The simulation time reduction in IS depends on another probability density function (p.d.f.) called simulation p.d.f. The previous IS simulation method can not evaluate the error probability on the low SNR and waterfall region. We derive the optimal simulation p.d.f. which gives the perfect estimator. A new simulation p.d.f. design, which is related to the optimal one, is proposed to overcome the problem of the previous IS method. The proposed IS simulation can evaluate all possible error patterns. Finally, some computer simulations show that the proposed method can evaluate the error probability on the low SNR, waterfall, and error floor regions. At the evaluation of the BER of 10-7, the simulation time of the proposed method is about 1/350 times as short as that of the Monte-Carlo simulation. When the BER is less than 710-8, the proposed method requires shorter simulation time than the conventional IS method.

  • Chaotic Oscillator and Other Techniques for Detection of Weak Signals

    Bo LE  Zhong LIU  Tianxiang GU  

     
    LETTER

      Vol:
    E88-A No:10
      Page(s):
    2699-2701

    We present a new method to detect weak linear frequency modulated (LFM) signals in strong noise using the chaos oscillator. Chaotic systems are sensitive to specific signals yet immune to noise. With our new method we firstly use the Radon-Wigner transform to dechirp the LFM signal. Secondly, we set up a chaotic oscillator sensitive to weak signals based on the Duffing equation, and poising the system at its critical state. Finally, we input the dechirped sequence into the system as a perturbation of the driving force. A weak signal with the same frequency will lead to a qualitative transition in the system state. The weak signal in the presence of strong noise can then be detected from the phase transition of the phase plane trajectory of the chaotic system. Computer simulation results show that LFM signals with an SNR lower than -27 dB can be detected by this method.

  • RO-Based Self-Organizing Neuro-Fuzzy Approach for HDD Positioning Control

    Chunshien LI  Kuo-Hsiang CHENG  Jin-Long CHEN  Chih-Ming CHEN  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2615-2626

    The requirement for achieving the smoothness of mode transit between track seeking and track following has become a challenging issue for hard disk drive (HDD) motion control. In this paper, a random-optimization-based self-organizing neuro-fuzzy controller (RO-SNFC) for HDD servo system is presented. The proposed controller is composed of three designs. First, the concept of pseudo-errors is used to detect the potential dynamics of the unknown plant for rule extraction. Second, the propensity of the obtained pseudo-errors is specified by a cubic regression model, with which the cluster-based self-organization is implemented to generate clusters. The generated clusters are regarded as the antecedents of the T-S fuzzy "IF-THEN" rules. The initial knowledge base of the RO-SNFC is established. Third, the well-known random optimization (RO) algorithm is used to evolve the controller parameters for control efficiency and robustness. In this paper, a motion reference curve for HDD read/write head is employed. With the reference velocity curve, the RO-SNFC is used to achieve the optimal positioning control. From the illustrations, the feasibility of the proposed approach for HDD servo systems is demonstrated. Through the comparison to other approaches, the excellent performance by the proposed approach in access time and positioning smoothness is observed.

  • Shift-Invariant Associative Memory Based on Homogeneous Neural Networks

    Hiromi MIYAJIMA  Noritaka SHIGEI  Shuji YATSUKI  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2600-2606

    This paper proposes homogeneous neural networks (HNNs), in which each neuron has identical weights. HNNs can realize shift-invariant associative memory, that is, HNNs can associate not only a memorized pattern but also its shifted ones. The transition property of HNNs is analyzed by the statistical method. We show the probability that each neuron outputs correctly and the error-correcting ability. Further, we show that HNNs cannot memorize over the number,, of patterns, where m is the number of neurons and k is the order of connections.

  • A New Core and Delta Detection for Fingerprints Using the Extended Relation Graph

    Tomohiko OHTSUKA  Akiyoshi KONDO  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2587-2592

    A new detection methodology for both of the core and the delta of the fingerprint using the extended relational graph is presented. This paper shows the way to detect both of the core loop and the delta loop from the extended relational graph, which we proposed in order to summarize the global feature of the fingerprint ridge pattern distribution. The experimental results for 180 fingerprint samples show that the processing time is ranging from 0.34 [sec] to 0.44 [sec] for each fingerprint image by using Pentium 4 1.8 GHz Processor. In our experiments, the core and the delta were successfully extracted in 94.4% of the 180 samples.

  • On Transformation between Discretized Bernoulli and Tent Maps

    Daisaburo YOSHIOKA  Akio TSUNEDA  Takahiro INOUE  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2678-2683

    In this paper, it is proved that there is a transformation between two types of nonlinear feedback shift register which can be regarded as implementation of the Bernoulli and tent maps with finite precision. This transformation can be interpreted as a sort of finite dimension version of topological conjugation between the Bernoulli and tent maps on continuous phase space. Several properties of periodic sequences generated from extended NFSRs are derived from the relation.

  • Real Time Search for Similar Hand Images from Database for Robotic Hand Control

    Kiyoshi HOSHINO  Takanobu TANIMOTO  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2514-2520

    The authors propose a system for searching the shape of human hands and fingers in real time and with high accuracy, without using any special peripheral equipment such as range sensor, PC cluster, etc., by a method of retrieving similar image quickly with high accuracy from a large volume of image database containing the complicated shapes and self-occlusions. In designing the system, we constructed a database in a way to be adaptable even to differences among individuals, and searched CG images of hand similar to unknown hand image, through extraction of characteristics using high-order local autocorrelational patterns, reduction of the amount of characteristics centering on principal component analysis, and prior rearrangement of data corresponding to the amount of characteristics. As a result of experiments, our system performed high-accuracy estimation of human hand shape where mean error was 7 degrees in finger joint angles, with the processing speed of 30 fps or over.

  • An Alternating-Phase Fed Single-Layer Slotted Waveguide Array in 76 GHz Band and Its Sidelobe Suppression

    Yuichi KIMURA  Masanari TAKAHASHI  Jiro HIROKAWA  Makoto ANDO  Misao HANEISHI  

     
    PAPER

      Vol:
    E88-C No:10
      Page(s):
    1952-1960

    This paper presents designs and performances of 76 GHz band alternating-phase fed single-layer slotted waveguide arrays. Two kinds of design, that is, uniform aperture illumination for maximum gain and Taylor distribution for sidelobe suppression of -25 dB, are conducted. High gain and high efficiency performance of 34.8 dBi with 57% is achieved for the former, while satisfactory sidelobe suppression of -20 dB in the H-plane and -23 dB in the E-plane with high efficiency is confirmed for the latter. The simple structure dispensing with electrical contact between the slotted plate and the groove feed structure is the key advantage of alternating-phase fed arrays and the slotted plate is just tacked on the feed structure with screws at the periphery. High gain and high efficiency performances predicted theoretically as well as design flexibility of the alternating-phase fed array are demonstrated in the millimeter wave frequency.

  • Resonance Analysis of Multilayered Filters with Triadic Cantor-Type One-Dimensional Quasi-Fractal Structures

    Ushio SANGAWA  

     
    PAPER-Electromagnetic Theory

      Vol:
    E88-C No:10
      Page(s):
    1981-1991

    Multilayered filters with a dielectric distribution along their thickness forming a one-dimensional quasi-fractal structure are theoretically analyzed, focusing on exposing their resonant properties in order to understand a dielectric Menger's sponge resonator [4],[5]. "Quasi-fractal" refers to the triadic Cantor set with finite generation. First, a novel calculation method that has the ability to deal with filters with fine fractal structures is derived. This method takes advantage of Clifford algebra based on the theory of thin-film optics. The method is then applied to classify resonant modes and, especially, to investigate quality factors for them in terms of the following design parameters: a dielectric constant, a loss tangent, and a stage number. The latter determines fractal structure. Finally, behavior of the filters with perfect fractal structure is considered. A crucial finding is that the high quality factor of the modes is not due to the complete self-similarity, but rather to the breaking of such a fractal symmetry.

  • Weight and Stopping Set Distributions of Two-Edge Type LDPC Code Ensembles

    Ryoji IKEGAYA  Kenta KASAI  Yuji SHIMOYAMA  Tomoharu SHIBUYA  Kohichi SAKANIWA  

     
    PAPER-Coding Theory

      Vol:
    E88-A No:10
      Page(s):
    2745-2761

    In this paper, we explicitly formulate the average weight and the stopping set distributions and their asymptotic exponents of two-edge type LDPC code ensembles. We also show some characteristics such as the symmetry and the conditions for zero of the weight distributions of two code ensembles. Further we investigate the relation between two code ensembles from the perspectives of the weight and stopping set distributions.

  • On the Aggregation of Self-Similar Processes

    Gianluca MAZZINI  Riccardo ROVATTI  Gianluca SETTI  

     
    PAPER

      Vol:
    E88-A No:10
      Page(s):
    2656-2663

    The problem of aggregating different stochastic process into a unique one that must be characterized based on the statistical knowledge of its components is a key point in the modeling of many complex phenomena such as the merging of traffic flows at network nodes. Depending on the physical intuition on the interaction between the processes, many different aggregation policies can be devised, from averaging to taking the maximum in each time slot. We here address flows averaging and maximum since they are very common modeling options. Then we give a set of axioms defining a general aggregation operator and, based on some advanced results of functional analysis, we investigate how the decay of correlation of the original processes affect the decay of correlation (and thus the self-similar features) of the aggregated process.

11221-11240hit(18690hit)