Algorithms are presented for the four elementary arithmetic operations, to perform reliable floating-point arithmetic operations. These arithmetic operations can be achieved by applying residue techniques to the weighted number systems and performed with no accuracy lost in the process of the computing. The arithmetic operations presented can be used as elementary tools (on many existing architectures) to ensure the reliability of numerical computations. Simulation results especially for the solutions of ill-conditioned problems are given with emphasis on the practical usability of the tools.

Vector quantization (VQ) is an attractive image compression technique. VQ utilizes the high correlation between neighboring pixels in a block, but disregards the high correlation between the adjacent blocks. Unlike VQ, side-match VQ (SMVQ) exploits codeword information of two encoded adjacent blocks, the upper and left blocks, to encode the current input vector. However, SMVQ is a fixed bit rate compression technique and doesn't make full use of the edge characteristics to predict the input vector. Classified side-match vector quantization (CSMVQ) is an effective image compression technique with low bit rate and relatively high reconstruction quality. It exploits a block classifier to decide which class the input vector belongs to using the variances of neighboring blocks' codewords. As an alternative, this paper proposes three algorithms using gradient values of neighboring blocks' codewords to predict the input block. The first one employs a basic gradient-based classifier that is similar to CSMVQ. To achieve lower bit rates, the second one exploits a refined two-level classifier structure. To reduce the encoding time further, the last one employs a more efficient classifier, in which adaptive class codebooks are defined within a gradient-ordered master codebook according to various prediction results. Experimental results prove the effectiveness of the proposed algorithms.

A 23.3 mm2 32 Mb embedded DRAM (eDRAM) macro has been fabricated using 0.18 µm triple-well 4-metal embedded DRAM process technology to realize an accelerated 3-D graphics controller. The array architecture, using a dual-port sense amplifier, achieves the column access latency of two cycles at 222 MHz and a peak data rate of 14.2 4 GB/s at 4 macros. The process cost has been kept low by using VT-MOS circuit technology and taking advantage of a characteristic of dual-gate oxide process technology. A tRAC of 11.6 ns at 2.0 V is achieved using a 'pre-detect redundancy' circuit.

A quasi-synchronous (QS) Multi-Carrier time division duplex DS-CDMA is studied for reverse link on multipath indoor environment. Quasi-synchronous DS-CDMA drastically reduces the effect of multiple access interference with several interesting features of time division duplex (TDD) mode for mobile communications. In this paper, we use the time division duplex transmission mode and each user appropriately adjusts its transmission time, through feed back control from the base station, so its signal can arrive at the base station synchronously with the other mobile stations. This paper evaluates the performance of a quasi-synchronous multi-carrier TDD DS-CDMA for reverse link on multipath indoor environment. The performance results are shown with different quasi-synchronous accuracy and power control error values. Orthogonal codes are used for spreading the signals in QS transmission. On the other hand, random codes are used for an asynchronous transmission. From the results, when the performance of asynchronous system is assumed to be a reference, we can see that the constraint of quasi-synchronous accuracy equals 2.3 chips of multi-carrier system at spreading factor 32.

Since the deployment of base stations (BS's) is far from optimum in 3-dimensional (3-D) space, i.e., the vertical baseline is relatively shorter than the planar baseline, the geometric degradation of precision of the altitude estimate is larger than that of the planar location. This paper considers the problem of 3-D range location and attempt to improve the altitude estimate. We first use a volume formula of tetrahedron to transform the range measurements to the volume measurements, then a novel pseudo-linear solution is proposed based on a linear relationship between the rectangular and the volume coordinates. Theory analysis and numerical examples are included to show the improved accuracy of the altitude estimate of mobile location. Finally, an improved estimate of 3-D mobile location is given by solving a set of augmented linear equations.

This paper assesses the performance of the handoff algorithm based on distance and RSSI measurements in a multi-cellular environment by computer simulation. The algorithm performs a handoff if handoff initiation conditions, handoff possible conditions, and handoff selective conditions are met. The performance criteria are based on the average number of handoffs, the crossover points and the average number of outages. Numerical results are presented to demonstrate the feasibility of the algorithm. The performance of the distance-assisted handoff algorithm is compared with that of a conventional algorithm that utilizes signal strength alone. Overall, the distance-assisted algorithm exhibits higher performance in average number of handoffs and the crossover points, yet exhibits a higher number of outages on average than the conventional algorithm.

We propose and analyze a new efficient handoff scheme called Splitted-Rating Channel Scheme in UMTS networks, and we analyze the call level performance of splitted-rating channel scheme and then packet level performance of downlink traffic at UMTS circuit-switched networks. In order to reduce the blocking probability of originating calls and the forced termination probability of handoff calls, a splitted-rating channel scheme is applied to the multimedia UMTS networks. This multimedia network supports two classes of calls; narrowband call requiring one channel and wideband call requiring multiple channels. The channels in service for wideband call are splitted its channels for lending to originating call and handoff call according to threshold control policy. By assuming that arrivals of narrowband calls and arrivals of wideband calls are Poisson, we model the number of narrowband calls and the number of wideband calls in the one cell by Level Dependent Quasi-Birth-Death (QBD) process and obtain their joint stationary distribution. For packet level analysis, we first describe the downlink traffic from the base station to a mobile terminal in UMTS networks, and calculate the mean packet delay of a connected wideband call by using QBD analysis. Numerical examples show that our splitted-rating channel scheme reduces the blocking probability of originating call and the forced termination probability of handoff call with a little degradation of packet delay.

Active integrated antennas are a maturing topic. Many novel configurations have been described and system designers are how investigating how the advantages of compactness and increased functionality can be exploited in applications. In this paper, the various types of integrated antennas are discussed together with possible ways of exploiting the technology. New configurations of direct conversion integrated antennas are then described in detail, which illustrate some of the possibilities inherent in the technology.

The paper deals with the estimation method of system equations of dynamic behavior of an input-pricing mechanism by using the Genetic Programming (GP) and its applications. The scheme is similar to recent noise reduction method in noisy speech which is based on the adaptive digital signal processing for system identification and subtraction estimated noise. We consider the dynamic behavior of an input-pricing mechanism for a service facility in which heterogeneous self-optimizing customers base their future join/balk decisions on their previous experiences of congestion. In the GP, the system equations are represented by parse trees and the performance (fitness) of each individual is defined as the inversion of the root mean square error between the observed data and the output of the system equation. By selecting a pair of individuals having higher fitness, the crossover operation is applied to generate new individuals. The string used for the GP is extended to treat the rational form of system functions. The condition for the Li-Yorke chaos is exploited to ensure the chaoticity of the approximated functions. In our control, since the system equations are estimated, we only need to change the input incrementally so that the system moves to the stable region. By assuming the targeted dynamic system f(x(t)) with input u(t)=0 is estimated by using the GP (denoted (x(t))), then we impose the input u(t) so that xf= (t+1)=(x(t))+u(t) where xf is the fixed point. Then, the next state x(t+1) of targeted dynamic system f(x(t)) is replaced by x(t+1)+u(t). We extend ordinary control method based on the GP by imposing the input u(t) so that the deviation from the targeted level xL becomes small enough after the control. The approximation and control method are applied to the chaotic dynamics generating various time series based on several queuing models and real world data. Using the GP, the control of chaos is straightforward, and we show some example of stabilizing the price expectation in the service queue.

The Belousov-Zhabotinsky (BZ) reaction provides us important clues in controlling 2D phase-lagged stable synchronous patterns in an excitable medium. Because of the difficulty in computing reaction-diffusion systems in large systems using conventional digital processors, we here propose a cellular-automaton (CA) circuit that emulates the BZ reaction. In the circuit, a two-dimensional array of parallel processing cells is responsible for fast emulation, and its operation rate is independent of the system size. The operations of the proposed CA circuit were demonstrated by using a simulation program with integrated circuit emphasis (SPICE).

In this letter, we introduce a two-state turbo-TCM scheme based on the concatenated tree codes. The proposed scheme can achieve near capacity performance yet has considerably lower decoding complexity compared with other existing turbo-TCM codes.

This paper proposes a novel packet classification method using ternary content-addressable memory (TCAM), which can store very wide policy rules despite the limited width of TCAM. For IP version 6, policy rules could be 304 bits wide. This method enables us to use commercially available TCAM for packet classification and thus builds an ultra high-speed policy based packet forwarding engine for differentiated services on the Internet.

We developed a method for extracting negative examples when only positive examples are given as supervised data. This method calculates the probability of occurrence of an input example, which should be judged to be positive or negative. It considers an input example that has a high probability of occurrence but does not appear in the set of positive examples as a negative example. We used this method for one of important tasks in natural language processing: automatic detection of misspelled Japanese expressions. The results showed that the method is effective. In this study, we also described two other methods we developed for the detection of misspelled expressions: a combined method and a "leaving-one-out" method. In our experiments, we found that these methods are also effective.

There are several attempts to generate chaotic binary sequences by using one-dimensional maps. From the standpoint of engineering applications, it is necessary to evaluate statistical properties of sample sequences of finite length. In this paper we attempt to evaluate the statistics of chaotic binary sequences of finite length. The large deviation theory for dynamical systems is useful for investigating this problem.

In loudspeaker-based 3D audio systems, there are some acoustic crosstalk cancellation methods to enlarge the 'sweet spot' around a fixed listener position. However, these methods have common defect that most of them can be applied only to the specific narrow frequency band. In this letter, we propose the more robust acoustic crosstalk cancellation method so that we can cancel the crosstalk signal in far wider frequency band and enlarge 'sweet spot. ' For this goal, we apply a sum and difference filter to the conventional three loudspeaker-based 3D audio system.

Feature subset selection is an important preprocessing task for pattern recognition, machine learning or data mining applications. A Genetic Algorithm (GA) with a fuzzy fitness function has been proposed here for finding out the optimal subset of features from a large set of features. Genetic algorithms are robust but time consuming, specially GA with neural classifiers takes a long time for reasonable solution. To reduce the time, a fuzzy measure for evaluation of the quality of a feature subset is used here as the fitness function instead of classifier error rate. The computationally light fuzzy fitness function lowers the computation time of the traditional GA based algorithm with classifier accuracy as the fitness function. Simulation over two data sets shows that the proposed algorithm is efficient for selection of near optimal solution in practical problems specially in case of large feature set problems.

The radar cross section (RCS) of a dielectric-coated cylindrical cavity was measured and the measurements were compared with those calculated according to the iterative physical optics (IPO). The IPO analysis used the equivalent-impedance boundary condition (EIBC) based on transmission-line theory which takes into account the thickness of the coating. It was consequently found that this condition is much more effective than the ordinary-impedance boundary condition based on the intrinsic impedance of the material.

This paper proposes a stable rate allocation algorithm for ABR service in ATM networks. The main goals in designing this algorithm are to speed up the convergence according to the max-min fairness criterion and to maximize the network utilization while the switch queue length can be properly controlled. Importantly, the set goals should be achieved in a wide range of network conditions without the need for adjusting the algorithm parameters. The algorithm is targeted to work in various networking environments with additional criteria as extended from the work of E-FMMRA (Enhanced Fast Max-Min Rate Allocation) and ERICA+ (Explicit Rate Indication for Congestion Avoidance) . The additional design criteria include the ability to enhance a large number of ABR connections and staggered TCP connections as well as to perform an accurate traffic averaging. The algorithm is analytically proved to be convergent. Simulation results indicate that the proposed algorithm achieves the goals in all evaluated configurations. However, it has some limitations when working in the large-scale network due to its per-connection accounting. It is not recommended to implement the algorithm with a switch that has a small buffer size due to its relatively long averaging interval.

We present an efficient algorithm using a region-based texture feature for the extraction of texture regions. The key idea of this algorithm is to use the variations of local correlation coefficients (LCCs) according to different orientations to classify texture and shade regions. Experimental results show that the proposed feature suitably extracts the regions that appear visually as texture regions.

Let us introduce n ( 2) mappings fi (i=1,2,,n) defined on complete linear metric spaces (Xi-1, ρ) (i=1,2,,n), respectively, and let fi:Xi-1 Xi be completely continuous on bounded convex closed subsets Xi-1(0) Xi-1, (i=1,2,,n 0), such that fi(Xi-1(0)) Xi(0). Moreover, let us introduce n set-valued mappings Fi : Xi-1 Xi (Xi)(the family of all non-empty closed compact subsets of Xi), (i=1,2,,n 0). Here, we have a fixed point theorem on the successively recurrent system of set-valued mapping equations: xi Fi(xi-1, fi(xi-1)), (i=1,2,,n 0). This theorem can be applied immediately to analysis of the availability of system of circular networks of channels undergone by uncertain fluctuations and to evaluation of the tolerability of behaviors of those systems. In this paper, mathematical situation and detailed proof are discussed, about this theorem.