Recursive least absolute(RLA) error algorithm is derived which is basically the sign algorithm (SA) combined with recursive estimation of the inverse covariance matrix of the reference input. The name RLA comes from the absolute error criterion. Analysis of the transient behavior and steady-state performance of the RLA algorithm is fully developed. Results of experiment show that the RLA algorithm considerably improves the convergence rate of the SA while preserving the robustness against impulse noise. Good agreement between the simulation and the theoretically calculated convergence validates the analysis.

This paper describes special-purpose hardware for large-scale logic simulation, called SP2, which executes an event driven algorithm and can simulate up to sixteen million gates. SP2 was developed, in 1992, for system verification of large-scale computer designs as a successor to SP1, which was developed in 1987. SP2 provides enhanced performance, throughput, and delay accuracy over SP1. Since 1992, SP2 has been widely used for system-level simulation of mainframes, super computers, UNIX servers and microprocessors. It is used as a powerful simulator, in all stages of design verification, or in early stages, before regression testing, by using emulators.

In this paper, we propose a medium access control (MAC) protocol for multimedia code division multiple access (CDMA) communications. In the proposed protocol, a base station (BS) estimates the instantaneous number of simultaneously transmitted packets in the future slots with exploiting a stochastic property of traffic. In order to carry out this estimation, we employ an adaptive algorithm. We evaluate the performance of the proposed protocol by comparing that with two different cases. One is no estimation case and the other is perfect estimation case. From these results, we clarify the advantage of the proposed MAC protocol.

The problem of the super-resolution time delay estimation of the real stationary signals is addressed in this paper. The time delay estimation is first converted into a frequency estimation problem. Then a MUSIC-type algorithm to estimate the subsequent frequency from the single-experiment data is proposed, which not only avoids the mathematical model mismatching but also utilizes the advantages of the subspace-based methods. The mean square errors (MSEs) of the time delay estimate of the MUSIC-type method for varying signal-to-noise (SNR) and separation of two received signal components are shown to illustrate that they approximately coincide with the corresponding Cramer-Rao bound (CRB). Finally, the comparison between the MUSIC-type method and the other conventional methods is presented to show the advantages of the proposed method in this paper.

We suggest a new probe message structure and an efficient probe-based deadlock detection and recovery algorithm that can be used in distributed database systems. We determine the characteristics of the probe messages and suggest an algorithm that can reduce the communication cost required for deadlock detection and recovery.

The motion estimation can choose the most suitable algorithm for different kinds of motion types, formats, and characteristics. The video encoding system can be optimized for quality, speed, and power consumption. In this paper, we propose a reconfigurable approach to a motion estimation algorithm and hardware architecture. The proposed algorithm determines motion type and then selects adapted block-matching algorithm for different kinds of motion sequences. The quality of our algorithm is better than that of the TSS and the BBGDS algorithm, or comparable to the performance of the better of the two, and the computational complexity of our algorithm is significantly less than that of the TSS. We also propose hardware architecture for realizing two kinds of motion estimations in the same hardware. We implemented the flexible and reconfigurable hardware architecture by using address generator unit, delay unit, and parameters and by using the hardware description language (VHDL) and the SYNOPSYS synthesis design tools. We analyze the performance of the algorithm and present adapted algorithm for a low cost real time application.

This paper presents a flexible learning algorithm for the binary neural network that can realize a desired Boolean function. The algorithm determines hidden layer parameters using a genetic algorithm. It can reduce the number of hidden neurons and can suppress parameters dispersion. These advantages are verified by basic numerical experiments.

This letter presents text-independent speaker identification results for telephone speech. A speaker identification system based on Karhunen-Loeve transform (KLT) derived from codebook design using genetic algorithm (GA) is proposed. We have combined genetic algorithm (GA) and the vector quantization (VQ) algorithm to avoid typical local minima for speaker data compression. Identification accuracies of 91% were achieved for 100 Mandarin speakers.

A siphon-trap of a Petri net N is defined as a place set S with S = S, where S = { u| N has an edge from u to a vertex of S} and S = { v| N has an edge from a vertex of S to v}. A minimal siphon-trap is a siphon-trap such that any proper subset is not a siphon-trap. The following polynomial-time algorithms are proposed: (1) FDST for finding, if any, a minimal siphon-trap or even a maximal class of mutually disjoint minimal siphon-traps of a given Petri net; (2) FDSTi that repeats FDST i times in order to extract more minimal siphon-traps than FDST. (3) STFM_T (STFM_Ti, respectively) which is a combination of the Fourier-Motzkin method and FDST (FDSTi) and which has high possibility of finding, if any, at least one minimal-support nonnegative integer invariant.

Various niching methods have been developed to maintain the population diversity. The feature of these methods is to prevent the proliferation of similar individuals in the niche (subpopulation) based on the similarity measure. This paper demonstrates that they are effective to avoid premature convergence in a case where only one global optimum in multimodal functions is searched. The performance of major niching methods in such a case is investigated and compared by experiments using seven benchmark functions. The niching methods tested in this paper are deterministic crowding, probabilistic crowding, restricted tournament selection, clearing procedure and diversity-control-oriented genetic algorithm (DCGA). According to the experiment, each method shows a fairly good global-optimum-searching capability. However, no method can completely avoid premature convergence in all functions. In addition, no method shows a better searching capability than the other methods in all functions.

We describe in this paper our experience of developing a large-scale, highly distributed multi-agent system using wireless-networked sensors. We provide solutions to the problems of localization (position estimation) and dynamic, real-time mobile object tracking, which we call PET problems for short, using wireless sensor networks. We propose system architectures and a set of distributed algorithms for organizing and scheduling cooperative computation in distributed environments, as well as distributed algorithms for localization and real-time object tracking. Based on these distributed algorithms, we develop and implement a hardware system and software simulator for the PET problems. Finally, we present some experimental results on distance measurement accuracy using radio signal strengths of the wireless sensors and discuss future work.

This paper discusses encoding of vehicular position information using predictive algorithms in inter-vehicle communications (IVC) from the viewpoints of source coding and noisy channels. Two vehicular driving models are assumed; one is the 15-mode as a suburban rapid transit driving pattern, the other is called calming mode as a street-driving pattern. Three types of schemes are compared; a pulse code modulation (PCM) scheme, a predictive coding (PC) scheme, and the variable interval prediction (VIP) scheme that is proposed here. This paper assumes that precise position information is got from a positioning system, and that all the transmitters and receivers have common predictors. Performance comparisons of the three types of schemes are carried out both of noiseless and noisy channels. Results show that the VIP scheme is superior to any other scheme.

We present pipelined simple matching, called PSM, for an input buffered switch to relax the scheduling timing constraint by modifying pipelined maximal-sized matching (PMM). Like the pipelined manner of PMM, to produce the matching results in every time slot, PSM employs multiple subschedulers which take more than one time slot to complete matching. Using only head-of-line information of input buffers, PSM successively sends each request to all subschedulers to provide a better matching opportunity. To obtain better performance, PSM uses unique starting points of scheduling pointers in which the difference between the starting points is equal for any two adjacent subschedulers for a same output. Using computer simulations under a uniform traffic, we show PSM is more appropriate than PMM for pipelined scheduling of an input buffered switch.

Multiple access interference (MAI) due to many simultaneous users is the main factor that limits the performance of DS-CDMA system. Multiuser detection is a method to avoid performance degradation due to MAI. We propose a blind multiuser detection method based on the algorithm consisting of two-stage decoding process, i.e., linearly constrained constant modulus (LCCM) and iterative least squares (ILS). The computer simulations confirmed that the algorithm is near-far resistant and that the proposed method is effective in the application to the slow fading channels.

According to the grey data generating techniques in grey system theory, we propose a novel cryptosystem, whose applications can develop a new direction in the field of information security. In this paper, we present the concepts of sum-lock, difference-lock, sum-ladder, and difference-ladder. By using these concepts, we can obtain a cryptosystem with lock generation and sum-difference replacement ladder. In addition, we provide the encryption and decryption algorithms of our cryptosystem and adopt an illustrative example to verify it.

An adaptive array antenna should be applied for suppression of CCI in the spatial domain. However, the adaptive array antenna has some problems as follows. Because the adaptive array antenna takes a long time to converge to the optimum antenna weights, it's hard to track in case of quick varying channel. On the other hand, processing burden increases with the number of elements in the array antenna. To solve these problems, we propose an adaptive array antenna using array antenna as element antennas, the so-called "Layered array antenna." At the 1st layer, sector area are defined. We can change the sector areas according to the DOA distribution, because the sector areas are defined by the antenna weights. At the 2nd layer, MMSE is performed. Interference that couldn't be suppressed at the 1st layer is suppressed at the 2nd layer. By the proposed system, we confirmed higher convergence speed while relieving processing complexity.

In this paper, a contention-based reservation MAC protocol is proposed for non-real-time burst traffic class in wireless ATM networks. The proposed protocol is characterized by the contention-based transmission of the reservation request and contention-free transmission of burst traffic. The design objective of the proposed protocol is to reduce contention delay during the contention phase of a connection. In order to reduce collision of reservation requests, the base station calculates the transmission probability based on the estimated load of reservation requests and the number of random access minislots, and broadcasts it over the frame header period of downlink channel. Wireless terminal, which has traffic burst, selects a random access minislot and transmits its reservation request with a received transmission probability. Based on the successfully received reservation, the scheduler allocates the uplink data slots to wireless terminal. Simulation results show that the proposed protocol can provide higher channel utilization, and furthermore, maintains constant delay performance in a heavy traffic environment.

This paper presents an efficient graph-based evolutionary optimization technique called Evolutionary Graph Generation (EGG) and its extension to a parallel version. A new version of parallel EGG system is based on a coarse-grained model of parallel processing and can synthesize heterogeneous networks of various different components efficiently. The potential capability of parallel EGG system is demonstrated through the design of current-mode logic circuits.

As we move toward the transition to the IPv6 next generation network environment, it is necessary to realize heterogeneous communications between IPv6 and IPv4 terminals without sacrificing any convenience or frameworks of current communication methods. Mechanisms that satisfy such requirements are called translators. This paper categorizes various translator mechanisms and clarifies their characteristics. As a result of analyses, this paper proposes a SOCKS-based IPv6/IPv4 Translator, and describes its design and implementation. Compared with other translator mechanisms, the SOCKS-based translator have small constraints and good characteristics. For example, it can integrate DNS name resolving procedures, which is an important mechanism for the transition. The translator has already been implemented and it has been proved that it can support typical communication services such as telnet, ftp, http, mail without any problems.

The input queued (IQ) switching architecture is becoming an attractive alternative for high-speed switches owing to its scalability. In this paper, three new algorithms, referred to as the maximum credit first (MCF), enhanced MCF (EMCF), and iterative MCF (IMCF) algorithms, are introduced. Simulations show that both MCF and IMCF have similar performance as the Birkhoff-von Neumann decomposition (BVND) algorithm, which can provide cell delay bound and 100% throughput, with lower off-line computational and on-line memory complexity. Simulations also show the fairness of MCF is much better than that of BVND. Theoretic analysis shows that the EMCF algorithm has a better performance than MCF in terms of throughput and cell delay with the same complexity level as MCF. Simulation results indicate the EMCF algorithm has much lower average cell delay and delay variance as compared to the BVND algorithm.