We propose an adaptive plastic-landmine visualizing radar system employing a complex-valued self-organizing map (CSOM) dealing with a feature vector that focuses on variance of spatial- and frequency-domain inner products (V-CSOM) in combination with aperture synthesis. The dimension of the new feature vector is greatly reduced in comparison with that of our previous texture feature-vector CSOM (T-CSOM). In experiments, we first examine the effect of aperture synthesis on the complex-amplitude texture in space and frequency domains. We also compare the calculation cost and the visualization performance of V- and T-CSOMs. Then we discuss merits and drawbacks of the two types of CSOMs with/without the aperture synthesis in the adaptive plastic-landmine visualization task. The V-CSOM with aperture synthesis is found promising to realize a useful plastic-landmine detection system.

There is "Processing speed improvement of the automatic fare collection gate (AFC gate)" as one of the important problems to correspond to the passengers getting on and off in high density transportation at the peak. On the other hand, reliability is indispensable to handle the ticket that is the note. Therefore, the ticket system that has both high-speed processing and high reliability is necessary and indispensable. For the passenger's convenience improvement and maintenance cost reduction, wireless IC card ticket system is hoped. However, the high-speed processing and the high reliability are ambivalent at this system because of wireless communications between an IC card and an AFC gate; the faster the AFC gate processes the ticket, the poorer the reliability gets. In this thesis, it proposes the autonomous decentralized processing technology to meet high-speed processing in wireless IC ticket system and the requirement of high reliability. "IC card" "AFC" and "Central server" are assumed to be an autonomous system. It proposes "Decentralized algorithm of the fare calculation by IC card and the AFC" to achieve high-speed processing. Moreover, "Autonomous, decentralized consistency technology" in each subsystem is shown for high-reliability. In addition, to make these the effective one, "Wireless communication area enhancing technology (touch & going method)" and "Command system for the data high speed processing" are shown. These technologies are introduced into the Suica system of East Japan Railway and the effectiveness has been proven.

In this study, we propose a new acoustic model including the human ear canal and a thin tube earphone. The use of a tube earphone enables simultaneous listening of both virtual and real surrounding sound. First, we perform acoustic FDTD (finite difference time domain) simulations using an MRI head model with ear canals. The calculated external impedance viewed from the eardrum numerically shows that the influence of the inserted tube is small. A listening experiment with six subjects also confirms the effectiveness of a tube earphone. Second, we calculate HRTFs (head-related transfer functions) for eight directions in the horizontal plane to realize sound localization with a tube earphone. We also design inverse filters based on the propagation calculations including the characteristics of tube earphones. Finally we evaluate the localization system by another listening experiment with six subjects. The results reveal that the applicability of a system with tube earphones and inverse filters, particularly for the front directions.

The Oblivious Transfer (OT), introduced by Rabin in 1981, has become an important and fundamental cryptography technique. An OT protocol should have two important characteristics: the sender's privacy and the chooser's privacy. The sender is a party who will deliver a secret to the chooser. The chooser is another party who acts as receiver to learn some information about the input from the sender. The chooser learns of certain information concerning the sender's input while the sender is not allowed to know what the chooser has learned. Moreover, the chooser cannot acquire any messages that he/she did not choose. Naor and Pinkas have recently proposed an efficient oblivious transfer protocol (EOT) that implementes 1-out-of-n protocol, but this EOT has a flaw: it cannot withstand "the same message attack." In this paper, we will improve Naor and Pinkas EOT and make it resistant to "the same message attack."

Locality in high frequency diffraction is embodied in the Method of Moments (MoM) in view of the method of stationary phase. Local-domain basis functions accompanied with the phase detour, which are not entire domain but are much larger than the segment length in the usual MoM, are newly introduced to enhance the cancellation of mutual coupling over the local-domain; the off-diagonal elements in resultant reaction matrix evanesce rapidly. The Fresnel zone threshold is proposed for simple and effective truncation of the matrix into the sparse band matrix. Numerical examples for the 2-D strip and the 2-D corner reflector demonstrate the feasibility as well as difficulties of the concept; the way mitigating computational load of the MoM in high frequency problems is suggested.

In conventional OFDM systems, the effect of inter-block-interference (IBI) can be completely removed by inserting sufficient redundant symbols between successive transmission blocks. In this paper, based on the reformulated received block symbols of the discrete multirate filterbanks model, a new transceiver model for the cyclic prefix (CP) OFDM systems is proposed, associated with the oblique projector technique (view as the pre-processor for achieving IBI-free). Consequently, a novel ISI-free receiver with the zero-order FIR zero-forcing (ZF) filterbanks equalizer can be devised, under noise-free environment. For performance comparison the bit-error-rate (BER) is investigated for the cases of noisy and noise-free channels. In all cases, viz., the length of CP is shorter or longer than the order of the channel impulse response, we show that the same BER performance compared with the one suggested in [3] can be achieved, under the same assumptions and conditions. Since a simple cascade configuration of the IBI cancellation using the oblique projector followed by the ISI cancellation using the zero-order FIR ZF filterbanks equalizer can be realized for OFDM systems with sufficient or insufficient CP, the complexity of transceiver design can be reduced.

An order selection scheme for two-sided oblique projection-based interconnect reduction will be investigated. It will provide a guideline for terminating the conventional nonsymmetric Pade via Lanczos (PVL) iteration process. By exploring the relationship of the system Grammians of the original network and those of the reduced network, it can be shown that the system matrix of the reduced-order system generated by the two-sided oblique projection can also be expressed as those of the original interconnect model with some additive perturbations. The perturbation matrix only involves bi-orthogonal vectors at the previous step of the nonsymmetric Lanczos algorithm. This perturbation matrix will provide the stopping criteria in the order selection scheme and achieve the desired accuracy of the approximate transfer function.

This letter describes an efficient architecture for a Software Defined Radio (SDR) Wideband Code Division Multiple Access (WCDMA) receiver using for high performance wireless communication systems. The architecture is composed of a Radio Frequency (RF) front-end, an Analog-to-Digital Converter (ADC), and a Quadrature Amplitude Modulation (QAM) demodulator. A coherent demodulator, with a complete digital synchronization scheme, achieves the bit-error rate (BER) of 10-6 with the implementation loss of 0.5 dB for a raw Quadrature Phase Shift King (QPSK) signal.

A systematic method is introduced to the computational synthesis of CMOS voltage followers (VFs). The method is divided in three steps: generation of the small-signal circuitry by selection of nullators to model the behavior of a VF, and addition of norators to form nullator-norator joined-pairs; generation of the bias circuitry by addition of ideal biases according to the properties of nullators and norators; and synthesis of the joined-pairs by MOSFETs, and of the current-biases by CMOS current mirrors. It is shown that the proposed synthesis method has the capability to generate already known and new CMOS VF topologies.

In this paper, a new algorithm for the optimal training sequence with respect to sequence length in 1-dimensional cluster-based sequence equalizers (1-D CBSE) is presented. The proposed method not only removes the step of random training sequence selection but also shortens the length of the selected training sequences. The superiority of the new method is demonstrated by presenting several simulation results of quadrature phase shift keying (QPSK) signaling schemes and related analyses.

This paper presents a standard cell-based frequency synthesizer with dynamic frequency counting (DFC) for multiplying input reference frequency by N times. The dynamic frequency counting loop uses variable time period to estimate and tune the frequency of digitally-controlled oscillator (DCO) which enhances frequency detection's resolution and loop stability. Two ripple counters serve as frequency estimator. Conventional phase-frequency detector (PFD) thus is replaced with a digital arithmetic comparator to yield a divider-free circuit structure. Additionally, a 15 bits DCO with the least significant bit (LSB) resolution 1.55 ps is designed by using the gate capacitance difference of 2-input NOR gate in fine-tuning stage. A modified incremental data weighted averaging (IDWA) circuit is also designed to achieve improved linearity of DCO by dynamic element matching (DEM) skill. Based on the proposed standard cell-based frequency synthesizer, a test chip is designed and verified on 0.35-µm complementary metal oxide silicon (CMOS) process, and has a frequency range of (18-214) MHz at 3.3 V with peak-to-peak (Pk-Pk) jitter of less than 70 ps at 192 MHz/3.3 V.

Fixed polarity Reed-Muller expressions (FPRMs) exhibit several useful properties that make them suitable for many practical applications. This paper presents an exact minimization algorithm for FPRMs for incompletely specified functions. For an n-variable function with α unspecified minterms there are 2n+α distinct FPRMs, and a minimum FPRM is one with the fewest product terms. To find a minimum FPRM the algorithm requires to determine an assignment of the incompletely specified minterms. This is accomplished by using the concept of integer-valued functions in conjunction with an extended truth vector and a weight vector. The vectors help formulate the problem as an assignment of the variables of integer-valued functions, which are then efficiently manipulated by using multi-terminal binary decision diagrams for finding an assignment of the unspecified minterms. The effectiveness of the algorithm is demonstrated through experimental results for code converters, adders, and randomly generated functions.

This paper presents a fuzzy optimization based scheduling method for the manufacturing systems with uncertain production capacities. To address the uncertainties efficiently, the fuzzy optimization technique is used in defining the scheduling problem. Based on the symmetric approach of fuzzy optimization and Lagrangian relaxation technique, a practical fuzzy-optimization based algorithm is developed. The computational experiments based on the real factory data demonstrate that the proposed method provides robust scheduling to hedge against uncertainties.

There are several optimization techniques available for improving rendering speed of direct volume rendering. An acceleration method using the hierarchical min-max map requires little preprocessing and data storage while preserving image quality. However, this method introduces computational overhead because of unnecessary comparison and level shift between blocks. In this paper, we propose an efficient space-leaping method using optimal-sized blocks. To determine the size of blocks, our method partitions an image plane into several uniform grids and computes the minimum and the maximum depth values for each grid. We acquire optimal block sets suitable for individual rays from these values. Experimental results show that our method reduces rendering time when compared with the previous min-max octree method.

In order to eliminate the co-channel and multi-path interference of quasi-synchronous code division multiple access (QS-CDMA) systems, spreading sequences with low or zero correlation zone (LCZ or ZCZ) can be used. The significance of LCZ/ZCZ to QS-CDMA systems is that, even there are relative delays between the transmitted spreading sequences due to the inaccurate access synchronization and the multipath propagation, the orthogonality (or quasi-orthogonality) between the transmitted signals can still be maintained, as long as the relative delay does not exceed certain limit. In this paper, several lower bounds on the aperiodic autocorrelation and crosscorrelation of binary LCZ/ZCZ sequence set with respect to the family size, sequence length and the aperiodic low or zero correlation zone, are derived. The results show that the new bounds are tighter than previous bounds for the LCZ/ZCZ sequences.

In this paper we propose a novel and efficient method for the optimization of the power/ground (P/G) network in VLSI circuit layouts with reliability constraints. Previous algorithms in the P/G network sizing used the sequence-of-linear-programming (SLP) algorithm to solve the nonlinear optimization problems. However the transformation from nonlinear network to linear subnetwork is not optimal enough. Our new method is inspired by the biological evolution and use the grid-genetic-algorithm (GGA) to solve the optimization problem. Experimental results show that new P/G network sizes are smaller than previous algorithms, as the fittest survival in the nature. Another significant advance is that GGA method can be applied for all P/G network problems because it can get the results directly no matter whether these problems are linear or not. Thus GGA can be adopted in the transient behavior of the P/G network sizing in the future, which recently faces on the obstacles in the solution of the complex nonlinear problems.

This letter presents a method of finding the optimal quantization stepsize that minimizes quantization loss and maximizes coded BER performance. We define 'Information Error Rate'(IER) and obtain the equation of the modified constraint length (Km) to obtain an upper bound of coded BER performance of a l bit quantized soft decision Viterbi decoder. Using IER and Km, we determine the optimal quantization stepsize of a 2 bit and 3 bit quantized soft decision decoding system in an AWGN channl with respect to SNR, and verify our strategies by simulation results.

The problem of multi-body motion segmentation is important in many computer vision applications. In this paper, we propose a novel algorithm called fuzzy k-subspace clustering for robust segmentation. The proposed method exploits the property that under orthographic camera model the tracked feature points of moving objects reside in multiple subspaces. We compute a partition of feature points into corresponding subspace clusters. First, we find a "soft partition" of feature points based on fuzzy k-subspace algorithm. The proposed fuzzy k-subspace algorithm iteratively minimizes the objective function using Weighted Singular Value Decomposition. Then the points with high partition confidence are gathered to form the subspace bases and the remaining points are classified using their distance to the bases. The proposed method can handle the case of missing data naturally, meaning that the feature points do not have to be visible throughout the sequence. The method is robust to noise and insensitive to initialization. Extensive experiments on synthetic and real data show the effectiveness of the proposed fuzzy k-subspace clustering algorithm.

In order to judge the goodness of zero correlation zone sequence sets, a new concept, called ZCZ characteristic, is proposed. Then by defining a sequence operation, i.e. correlation product, and establishing its basic properties, a new approach to construct sets of sequences with a large zero correlation zone is presented.

Given a set of n stations, the initialization problem is to assign each station a unique identification number, from 1 to n. In the single-hop wireless Networks with collision detection, Nakano and Olariu proposed an algorithm to build a partition tree and solve the problem. In this paper, we shall classify the partition tree into four parts. By reviewing the classification, we find that three ideas can improve the algorithm. We show that it needs 2.88n time slots for solving the problem containing n stations. After applying our three ideas, the number of time slots will be improved to 2.46n.