Hirofumi NAKAMURA Sadayuki MURASHIMA
A positive integer code EXEb,h,d(b1, h1,d0) is proposed. Its codeword for a positive integer n consists of three kinds of information: (1) how many times the number of n's digits can be subtracted by the terms of a progression including a geometric progression, (2) the rest of the subtractions, and (3) given value of the positive integer n. EXEb,h,d is a non-recursive type code. It is an asymptotically optimal code (for d1) and preserves the lexicographic,length, and number orders (for bh+2). Some examples of EXEb,h,d are also presented. Their codeword lengths are found to be shorter than the Amemiya and Yamamoto code CEk except for small positive integers.
Takeshi ASAHI Koichi ICHIGE Rokuya ISHII
This paper proposes a novel fast algorithm for the decomposition and reconstruction of two-dimensional (2-D) signals by box splines. The authors have already proposed an algorithm to calculate the discrete box splines which enables the fast reconstruction of 2-D signals (images) from box spline coefficients. The problem still remains in the decomposition process to derive the box spline coefficients from an input image. This paper first investigates the decomposition algorithm which consists of the truncated geometric series of the inverse filter and the steepest descent method with momentum (SDM). The reconstruction process is also developed to correspond to the enlargement of images. The proposed algorithm is tested for the expansion of several natural images. As a result, the peak signal-to-noise ratio (PSNR) of the reconstructed images became more than 50 dB, which can be considered as enough high level. Moreover, the property of box splines are discussed in comparison with 2-D (the tensor product of) B-splines.
Myint Myint SEIN Hiromitsu HAMA
This paper presents an accurate method for finding the 3D control points of the B-Spline curves. This method can automatically fit a set of data points with piecewise geometrically continuous cubic B-Spline curves. Iterating algorithm has been used for finding the 2D control points. And a new approach for shape reconstruction based on the control points of the curves on the object's surface is proposed. B-Spline patch, the extension of the B-Spline curves to surface, provides recovering the shape of the object in 2D approach. The 3D control points of the cubic B-Spline curves are computed from the factor decomposition of the measurement matrix of 2D control points. The multiple object approach is also proposed to reconstruct the 3D shape of each curves of an object. Some experiments are demonstrated to confirm the effectiveness of our proposed method.
In this paper, we deal with the problem of compatibility class encoding, and propose a novel algorithm for finding a good functional decomposition with application to LUT-based FPGA synthesis. Based on exploration of the design space, we concentrate on extracting a set of components, which can be merged into the minimum number of multiple-output CLBs or LUTs, such that the decomposition constructed from these components is also minimal. In particular, to explore more degrees of freedom, we introduce pliable encoding to take over the conventional rigid encoding when it fails to find a satisfactory decomposition by rigid encoding. Experimental results on a large set of MCNC91 logic synthesis benchmarks show that our method is quite promising.
Norimasa NUKAGA Masatoshi MITSUYA Hiroshi FUNAKUBO
The chemical stability of the constituent elements in polycrystalline Sr-Bi-Ta-O thin film with various Bi content prepared by metalorganic chemical vapor deposition (MOCVD) was investigated by X-ray photoelectron spectroscopy (XPS). Moreover, that of the epitaxial films was also investigated to estimate the effect of the grain boundary in polycrystalline films. Therefore, only the Bi element drastically changed from Bi3+ state to Bi0 one by the Ar sputtering. This change increased with increasing the Ta/Bi mole ratio in the film from 0.64 to 1.67. This result was observed not only for the polycrystalline films but also for the epitaxial films, suggesting that this is the grain character not grain boundary one. The stability and the leakage character of the film strongly depend on the constituent of the film.
Takahiro ASAI Tadashi MATSUMOTO
This paper presents the outline of the systolic array recursive least-squares (RLS) processor prototyped primarily with the aim of broadband mobile communication applications. To execute the RLS algorithm effectively, this processor uses an orthogonal triangularization technique known in matrix algebra as QR decomposition for parallel pipelined processing. The processor board comprises 19 application-specific integrated circuit chips, each with approximately one million gates. Thirty-two bit fixed-point signal processing takes place in the processor, with which one cycle of internal cell signal processing requires approximately 500 nsec, and boundary cell signal processing requires approximately 80 nsec. The processor board can estimate up to 10 parameters. It takes approximately 35 µs to estimate 10 parameters using 41 known symbols. To evaluate signal processing performance of the prototyped systolic array processor board, processing time required to estimate a certain number of parameters using the prototyped board was comapred with using a digital signal processing (DSP) board. The DSP board performed a standard form of the RLS algorithm. Additionally, we conducted minimum mean-squared error adaptive array in-lab experiments using a complex baseband fading/array response simulator. In terms of parameter estimation accuracy, the processor is found to produce virtually the same results as a conventional software engine using floating-point operations.
Yoshiyuki SHINKAWA Masao J. MATSUMOTO
Adaptation of software components to the requirements is one of the key concerns in Component Based Software Development (CBSD). In this paper, we propose a formal approach to compose component based systems which are adaptable to the requirements. We focus on the functional aspects of software components and requirements, which are expressed in S-sorted functions. Those S-sorted functions are transformed into Colored Petri Nets (CPN) models in order to evaluate connectivity between the components, and to evaluate adaptability of composed systems to the requirements. The connectivity is measured based on colors or data types in CPN, while the adaptability is measured based on functional equivalency. We introduce simple glue codes to connect the components each other. The paper focuses on business applications, however the proposed approach can be applied to any other domains as far as the functional adaptability is concerned.
Masahiro MOCHIZUKI Hideyuki TOKUDA
We propose a mechanism to facilitate the development of component-based mobile applications with adaptive behaviors. The design principles and communication patterns of legacy software systems will greatly change in a forthcoming environment, where a variety of computing devices become embedded in home and office environments, users move around with/without portable computing devices, and all the devices are interconnected through wired/wireless networks. In the proposed mechanism, Improvised Assembly Mechanism (IAM), we realize functionality to compose an application in an ad hoc manner and to achieve the adaptation of applications by adding, replacing, supplementing, and relocating components at system runtime according to various environmental changes such as the locational changes of computing devices and users. The mechanism is implemented as a built-in functionality of the Soul component, which is one of the fundamental elements in the Possession model.
In designing WLAN MAC protocols, several issues must be considered. Among them, the hidden-terminal and exposed-terminal problems are two of the most important issues. The hidden-terminal problem has been analyzed by many researchers and significant improvements have been made. The exposed-terminal problem, however, has not been fully considered in the design of WLAN MAC protocols. In this paper, we propose two protocols. In the first one, referred to as channel splitting protocol, the channel is split into two subchannels--the control channel and the data channel--to solve several problems inherent in existing protocols, including hidden terminal and exposed terminal problems. With channel splitting, a control frame is transmitted through the control channel alternatively of a data frame which is transmitted through the data channel. In the second protocol, referred to as RTR/ATR reservation protocol, hosts that want to transmit data reserve several slotted data channels in advance to increase performance, while the first protocol reserves only one transmission. In the second protocol, control frames are transmitted through the control channel independently of data frames. The performance of the proposed protocols is evaluated by simulation and compared with existing protocols.
Kazuhiko USHIO Hideaki FUJIMOTO
First, we show that the necessary and sufficient condition for the existence of a balanced bowtie decomposition of the complete tripartite multi-graph λ Kn1,n2,n3 is (i) n1=n2=n3 0 (mod 6) for λ 1,5 (mod 6), (ii) n1=n2=n3 0 (mod 3) for λ 2,4 (mod 6), (iii) n1=n2=n3 0 (mod 2) for λ 3 (mod 6), and (iv) n1=n2=n3 2 for λ 0 (mod 6). Next, we show that the necessary and sufficient condition for the existence of a balanced trefoil decomposition of the complete tripartite multi-graph λ Kn1,n2,n3 is (i) n1=n2=n3 0 (mod 9) for λ 1,2,4,5,7,8 (mod 9), (ii) n1=n2=n3 0 (mod 3) for λ 3,6 (mod 9), and (iii) n1=n2=n3 3 for λ 0 (mod 9).
Suguru ARIMOTO Pham Thuc Anh NGUYEN
This paper is concerned with analysis of nonlinear dynamics under geometric constraints that express pinching motions of a pair of multi-degrees of freedom fingers with soft tips. The dynamics of such a pair of soft fingers can be expressed by a set of complicated nonlinear differential equations with algebraic constraints, even if the motion is constrained in a plane. However, it is shown from the passivity analysis that dynamic stable grasping (pinching) can be realized by means of a feedforward input of desired internal force with coefficients composed of elements of Jacobian matrices plus a feedback of the difference between moments of rotation exerted at both sides of the object. It is shown in the case of a pair of 2 d.o.f. and 3 d.o.f. fingers (corresponding to a pair of thumb and index fingers) that a principle of linear superposition is applicable to design of additional feedback signals for controlling simultaneously the posture (rotational angle) and position of the mass center of the object, though the dynamics are nonlinear. A sufficient condition for applicability of the principle of superposition is discussed and given as a condition for unique stationary resolution of the overall motion to elementary motions (stable grasping, rotation control, x and y coordinates control). The principle implies that a skilled motion can be resolved into some of elementary motions which human can learn separately and independently.
Hak-Young KIM Won-Sik YOON Dae Jin KIM Young Han KIM
In this paper we propose a mobile positioning method based on a recursive least squares (RLS) algorithm for suppressing the non-line of sight (NLOS) effects in cellular systems. The proposed method finds the position of a mobile station from TOAs measured by three BSs. Simulation results show that the proposed method has a fast convergence time and greatly reduces the positioning error especially in NLOS situations. Thus it is expected that the proposed method can be effectively used in a dense urban environment.
Jar-Ferr YANG Yu-Hwe LEE Jen-Fa HUANG Zhong-Geng LEE
In this paper, we propose fast bitmap search algorithms to reduce the computational complexity of transform-based vector quantization (VQ) techniques, which achieve better quality in reconstructed images than the ordinary VQ. By removing the unlikely codewords in each step, the bitmap search method, which starts from the most significant bitmap then the successive significant ones, can save more than 90% computation of the ordinary transformed VQ. By applying to the singular value decomposition (SVD) VQ as an example, theoretical analyses and simulation results show that the proposed bitmap search methods dramatically reduce the computation and achieve invisible distortion in the reconstructed images.
The micro positioning systems using magnetic suspension technique, which is one of precision actuating method, have been suggested. Utilizing the various potentials such as the exclusion of a mechanical friction, they are being applied broadly to multi degrees of freedom (d.o.f) system requesting high accuracy or hybrid system requesting to be controlled position and force simultaneously. This paper presents the entire development procedure of a novel six d.o.f micro positioning system using mag-netic levitation, with a repulsive force mechanism covering the all d.o.f. First, the interactions between magnetic elements are modeled and the system design flow by an optimal location of the elements is given. A kinematic relationship between the measuring instruments and the levitated object is derived, and dynamic characteristics are identified by the narrow gap principles. And the main issues for control are discussed.
Kazuhiro NAKAMURA Shinji MARUOKA Shinji KIMURA Katsumasa WATANABE
Multi-cycle paths are paths between registers where 2 or more clock cycles are allowed to propagate signals, and the detection of multi-cycle paths is important in deciding proper clock period, timing verification and logic optimization. This paper presents a satisfiability-based multi-cycle path detection method, where the detection problems are reduced to CNF formulae and the satisfiability is checked using SAT provers. We also show heuristics on conversion from multi-level circuits into CNF formulae. We have applied our method to ISCAS'89 benchmarks and other sample circuits. Experimental results show the remarkable improvements on the size of manipulatable circuits.
Mizuki TAKAHASHI Nagisa ISHIURA Akihisa YAMADA Takashi KAMBE
This paper presents a method of thread composition in a hardware compiler Bach. Bach synthesizes RT level circuits from a system description written in Bach-C language, where a system is modeled as communicating processes running in parallel. The system description is decomposed into threads, i.e., strings of sequential processes, by grouping processes which are not executed in parallel. The set of threads are then converted into behavioral VHDL models and passed to a behavioral synthesizer. The proposed method attempts to find a thread configuration that maximize resource sharing among processes in the threads. Experiments on two real designs show that the circuit sizes were reduced by 3.7% and 14.7%. We also show the detailed statistics and analysis of the size of the resulting gate level circuits.
Jianting CAO Noboru MURATA Shun-ichi AMARI Andrzej CICHOCKI Tsunehiro TAKEDA Hiroshi ENDO Nobuyoshi HARADA
Magnetoencephalography (MEG) is a powerful and non-invasive technique for measuring human brain activity with a high temporal resolution. The motivation for studying MEG data analysis is to extract the essential features from measured data and represent them corresponding to the human brain functions. In this paper, a novel MEG data analysis method based on independent component analysis (ICA) approach with pre-processing and post-processing multistage procedures is proposed. Moreover, several kinds of ICA algorithms are investigated for analyzing MEG single-trial data which is recorded in the experiment of phantom. The analyzed results are presented to illustrate the effectiveness and high performance both in source decomposition by ICA approaches and source localization by equivalent current dipoles fitting method.
The constriction resistance of an electric contact has frequently been obtained using a model of only one circular contact spot of radius a. However, cases of a single contact spot are extremely rare as the interface of the electrical contact actually consists of numerous micro-contact spots. A contact is therefore regarded as the aggregate of several micro-contact spots, which are referred to collectively as a cluster. The constriction resistance of the cluster can be calculated as the sum of the self-resistance and mutual resistance of individual micro-contact spots. In the present study, this model is expanded slightly for practical application by normalizing a previous theoretical formula. In order to obtain the constriction resistance for contacts between composite materials and mating metals, EPMA analysis is applied so as to determine real micro-contact spots. Theoretical calculations of the constriction resistance of multiple contact spots is shown to be reasonably consistent with experimental results. In addition, the contact of a composite material and a mating metal is shown to be made up of multispots. The current was recognized experimentally to flow more easily at micro-contact spots in the cluster periphery. These experimental findings coincide with simulation results obtained by theoretical calculations.
Toshifumi MORIYAMA Yoshio YAMAGUCHI Hiroyoshi YAMADA
This paper presents a three-dimensional polarimetric detection result of targets buried in snowpack by synthetic aperture FM-CW radar system. Since the FM-CW radar is suitable for short range sensing and can be equipped with fully polarimetric capability, we further extended it to a polarimetric three-dimensional SAR system. A field experiment was carried out to image and detect targets in a natural snowpack of 280 cm deep. The polarimetric detection and identification schemes are the polarimetric filtering, three-component decomposition, and the power polarization anisotropy coefficient. These approaches to acquired data show the usefulness of three-dimensional polarimetric FM-CW SAR system.
Ding JIN Ying SU Jian Ping WANG Hao GONG
Post annealing treatment for CoCrPt magnetic thin films were tried in different thermal conditions, by changing the time of annealing procedure. Coercivity (Hc) improvement was achieved in annealed sample compared with those as deposited, in which as high as 5.2 kOe has been attained. To clarify the mechanism of annealing treatment on the magnetic properties, X-ray diffraction (XRD) spectrums of those samples and their magnetic properties were carefully studied. Co and Cr lattice parameters were separately calculated from different crystal lattice plane. It was found that a axis lattice spacing of Co hexagonal structure increases monotonically with increased annealing time. Variation of Co hcp peaks significance may due to Cr or Pt redistribution in the crystal grains and its boundaries. Combined with the grain size analysis of Co-rich area by X-ray diffraction peak broaden width, which was not very consistent with the result obtained from other's TEM and AFM studies, Cr diffusion was suggested to be the governing factor at short annealing time region. Co-rich grain growth should also be applied to explain the variation of magnetic properties in longer post annealing.