Evaluating analytically computer architecture performance is mostly cheap and quick. However, existing analytical performance evaluation techniques usually have a difficult and time-consuming modeling process. Moreover, existing techniques do not support well the capability for finding the bottleneck and its cause of a target system being evaluated. To address the above problems and to enhance analytical performance evaluation technology, in this paper we propose a software tool that accepts system models described in a specification language, generating an executable program that performs the actual performance evaluation. The whole approach is built on a subsystem-oriented performance evaluation tool, which is, in turn, based on a formal subsystem-oriented performance evaluation technique and a subsystem specification language.

In this paper, we study the optimal allocation of multimedia files in distributed network systems. In these systems, the files are shared by users connected with different servers geographically separated, and each file must be stored in at least one of servers. Users can access any files stored in any servers connected with high-speed communication networks. Copies of the files accessed frequently are to be stored in several servers that have databases. So, it is one of the most important problems how to assign the files to servers in view of costs and delays. Considering these problems in heterogeneous network environments, we present a new system model that covers wide range of multimedia network applications like VOD, CALS, and so on. In these systems, it is obvious that there is trading-off relationship between costs and delays. Our objective is to find the optimal file allocation such that the total cost is minimized subject to the total delay. We introduce a 0-1 integer programming formulation for the optimization problem, and find the optimal file allocation by solving these formulae.

A constant modulus adaptive array algorithm is derived using analysis and synthesis filter banks to permit adaptive digital beamforming for wideband signals. The properties of the CMA adaptive array using the filter banks are investigated. This array would be used to realize adaptive digital beamforming when this is difficult by means of ordinary (that is, non-subband) processing due to the limited speed of signal processor operations. As an actual application, we present a beamspace adaptive array structure that combines the analysis and synthesis filter banks with RF-domain multibeam array antennas, such as those utilizing optical signal processing.

In this paper, we propose a novel power distribution method which can be adopted in case of the nonuniform distribution for mobiles in DS/CDMA distributed power cellular system. DS/SS distributed power cellular system has been proposed for achieving RAKE reception in micro-cellular environment. In forward link of this system, optimum power distribution method which can minimize the required total transmitting power has been discussed. The performance of this system has been shown in case of the uniform distribution for mobiles. In this paper, first, we propose a novel method in case of the nonuniform distribution. In the proposed method, replacing the path and its combinations of signals from base stations successively, we can find a new condition of less power distribution which is passed over in a conventional distribution method. We adopt simple distribution models for mobiles and compare the proposed method with the other methods by computing the total transmitting power and the quantity of calculations. As a result, we show that it is possible to almost obtain optimum power distribution by using the proposed method. Next, we adopt a nonuniform distribution model, in which the difference of the number of users exists only in the center cell. Using this model, we compare the proposed method with the other methods by computing the total transmitting power, the quantity of calculations, and a probability of impossible power distribution. Finally, in order to simplify and decrease the quantity of calculations of the proposed method, we propose a modified calculation algorithm which is applicable in case of that a new mobile station has increased. And we show the performance of this algorithm.

The applications of adaptive arrays based on the digital beam forming technique are receiving wide attention. However, the adaptive control algorithm of the array antennas under TDMA systems is not well considered even though it requires particular consideration due to its intermittent bursts. In this paper, first, we propose a novel DOA (Direction of Arrival) estimation method which is suitable for TDMA bursts. Second, the HA (Howells-Applebaum) adaptive array based on the proposed DOA estimation method will be constructed for the terminals in the mobile communication systems using non-geostationary satellites . Then the performance of the DOA estimation method and the HA adaptive array will be examined through computer simulations and experiments.

Electrochemomechanical deformation (ECMD) of poly(o-methoxyaniline) (PoMAn) film has been studied in various acid solutions, such as Cl-, HSO4-, BF4-, and p-toluene sulfate. The magnitude of ECMD of the film depends linearly on the degree of oxidation of the film similarly to the case of polyaniline (PAn). 2. 53% of deformation ratios along the stretched direction are obtained for 30% of reduction. In contrast to that of PAn, however, the ECMDs of PoMAn do not markedly depend on the kind of anions. Transient responses of current and deformation are investigated by the potential application stepwise and the diffusion coefficient of ions in films. The results are discussed in terms of the effect of substituted methoxy group.

From an information geometric viewpoint, we investigate a characteristic of the submanifold of a mixture or exponential family in the manifold of finite discrete distributions. Using the characteristic, we derive a direct calculation method for an em-geodesic in the submanifold. In this method, the value of the primal parameter on the geodesic can be obtained without iterations for a gradient system which represents the geodesic. We also derive the similar algorithms for both problems of parameter estimation and functional extension of the submanifold for a data in the ambient manifold. These theoretical approaches from geometric analysis will contribute to the development of an efficient algorithm in computational complexity.

This paper presents a novel classified vector quantizer (CVQ) design algorithm which can control the rate and storage size for applications of image coding. In the algorithm, the classification of image blocks is based on the edge orientation of each block in the wavelet domain. The algorithm allocates the rate and storage size available to each class of the CVQ optimally so that the average distortion is minimized. To reduce the arithmetic complexity of the CVQ, we employ a partial distance codeword search algorithm in the wavelet domain. Simulation results show that the CVQ enjoys low average distortion, low encoding complexity, high visual perception quality, and is well-suited for very low bit rate image coding.

This paper newly proposes the CMT/IM/DD system for universal radio access networks where radio base stations (RBSs) and an optic backbone network are universally available among different radio services and providers. In the proposed system, the Chirp Fourier transformer at an RBS, converts the received FDM multiple radio service signals into optical TDM format signals, then transfers them over the optic fiber-link. This paper is focused on the discussion about the performance on the up-link of the CMT/IM/DD system. A new type of the configuration of CMT and the direct demodulation for the CMT signal are also proposed, and the SNR considering inter-symbol and inter-channel interferences caused by the CMT is theoretically analyzed. Analysis results show that the overall SNR performance of the CMT system is superior to the conventional SCM system when the number of radio channels is more than 26.

Non-uniform traffic can affect communications quality in microcell systems, and this disparity in communications quality between base stations (BSs) lowers the system efficiency in CDMA systems. If traffic distribution and propagation conditions are already known during the introduction of a CDMA system, it is desirable to design cell areas according to the non-uniformity of traffic distribution and BS locations. Cell area is determined by the transmission power of the pilot-signal from the BS and it is necessary to control the transmission power of mobile stations in the uplink, which is determined by the desired power level at the BS, according to the cell area. The disparity in communications quality can be rectified by optimally designing the two parameters of the pilot-signal power and desired power level. This paper describes an algorithm for setting both the pilot-signal power and the desired power level during the cell design stage in CDMA systems. The proposed algorithm operates that the communications qualities of all BSs in the system converge to average quality by adjusting the two parameters. The parameters of all BSs in the whole system can be determined through computer calculation. Through performance evaluations, we confirmed that the average SIRs of all BSs attained almost the same value and the variance between the BSs was less than half by adopting the cell design algorithm when there was dispersion in BS placement. This algorithm is also effective using the actual measured SIR after a system has been established.

Low-profile, miniaturized and highly efficient power inverters are required to light up backlights, which include cold cathode fluorescent lamps (CCFLs), in color liquid crystal displays (LCDs), replacing conventional power inverters with electromagnetic transformers. The object of this study is to actualize a power inverter to which a novel multilayered piezoelectric ceramic transformer operating in the third order longitudinal mode is applied. The piezoelectric transformer has a symmetrical structure in the lengthwise direction and its generating part operates in a piezoelectric stiffened mode in order to increase both energy conversion efficiency and power density. This transformer has great advantages. Namely, all the electronic terminals in this transformer can be connected at the vibration nodes of the transformer, which contributes to the guarantee of stable transformer performances at high power operation, and this transformer is superior in impedance matching against the backlight load at steady state, because the output impedance of this transformer is much lower than that of conventional Rosen type transformers. Then a power inverter with the transformer was fabricated. In this power inverter, a separately excited oscillation circuit was adopted to drive the transformer with high efficiency, and the transformer drive frequency was controlled by detecting the backlight current in order to adjust the backlight luminance properly. As a result, the fabricated power inverter exhibited more than 90% overall efficiency and 4. 5-W output power, which is enough power to light up a 9. 4 inch color LCD, including the stray capacitance loss resulting from CCFL mounting. The luminance value on a light transmission plate of the backlight was more than 2000 cd/m2.

In this paper, we consider the selection of analysis filters used in the delayless subband adaptive digital filter (SBADF) and propose to use simple analysis filters to reduce the computational complexity. The coefficients of filters are determined using the components of the first order Hadamard matrix. Because coefficients of Hadamard matrix are either 1 or -1, we can analyze signals without multiplication. Moreover, the conditions for convergence of the proposed method is considered. It is shown by computer simulations that the proposed method can converge to the Wiener filter.

In this paper, a new traffic sign detection algorithm and a symbol recognition algorithm are proposed. For a traffic sign detection, a dominant color transform is introduced, which serves as a tool of highlighting a dominant primary color, while discarding the other two primary colors. For a symbol recognition, the curvilinear shape distribution on a circle centered on the centroid of the symbol, called a circular pattern vector, is used as a spatial feature of the symbol. The circular pattern vector is invariant to scaling, translation, and rotation. As simulation results, the effectiveness of traffic sign detection and recognition algorithms are confirmed.

In this paper, we propose a new denoising algorithm based on the dyadic wavelet transform (DWT) for ECG signals corrupted with different types of synthesized noise. Using the property that DWT is overcomplete, we define some convex sets in the set of wavelet coefficients and give an iterative method of the projection on the convex sets. The results show that the noises are not only removed from ECG signals, but also the ECG signals are reconstructed, which is used in detecting QRS complex. The performance of the proposed algorithm is demonstrated by some experiments in comparison with the conventional methods.

A function approximation scheme for image restoration is presented to resolve conflicting demands for smoothing within each object and differentiation between objects. Images are defined by probability distributions in the augmented functional space composed of image values and image planes. According to the fuzzy Hough transform, the probability distribution is assumed to take a robust form and its local maxima are extracted to yield restored images. This statistical scheme is implemented by a feedforward neural network composed of radial basis function neurons and a local winner-takes-all subnetwork.

Error performance as well as ATM cell transfer characteristics in a new category of wireless access systems is discussed. Relocatable wireless access with neutral feature between the fixed and mobile systems can convey Mbit/s-order capacity with fairly high quality under line-of-sight propagation. It is an important question for such wireless access systems whether they are able to form a part of wired networks satisfying performance objectives specified in ITU-T Recommendations. This paper analyzes the characteristics of relocatable systems under Gamma-distribution fading environments, and clarifies quantitative relations between Bit Error Rate (BER), Severely Errored Second (SES), Errored Second (ES) and Cell Loss Ratio (CLR) in a calculation model employing QPSK and typical HEC (Header Error Control). Thus it is demonstrated for the first time that in most cases the dominant parameter is the SES objective. Also it will be possible for a relocatable system with appropriate fade margin to meet the ITU-T performance specifications.

In this paper, we present several traffic handling schemes for improving the QoSs (quality-of-services) in a micro-cell based PCS (personal communication services) network. Traffic handling schemes are devised for the efficient use of the limited radio resources with the increasing number of users and multimedia traffic. Both mathematical analysis and computer simulations are carried out for the performance evaluation in terms of the blocking probability of new call, the forced termination probability of handoff voice and data and the average delay of data. Analytical models by bivariate Markov processes are provided. It reveals that a finite queueing scheme for handoff delay sensitive data guarantees QoS metrics, such as the blocking probability of new voice and data and forced termination probability of handoff voice and data, as well as the efficient use of radio resources. The optimal number of reserved channels for handoff delay sensitive data and the optimal number of reserved channels for handoff traffic (in reserved channel scheme) are investigated and obtained. Dynamically controlled reserved channel schemes turn out to provide no significant performance improvement.

This paper describes an efficient method to simulate lossy coupled transmission lines based on the delay evaluation technique. First, we review the previous methods, and refer to several problems concerned with these methods. Next, a novel waveform relaxation-based simulation method is proposed, which uses the delay evaluation technique. This method enables to obtain the accurate transient waveforms using smaller number of moments than the other moment methods use, and is modified for acceleration by the generalized line delay window partitioning (GLDW) technique. Finally, this method is implemented in the waveform relaxation-based circuit simulator DESIRE3T+, and the performance is estimated.

The TMN that appears to operate the various communication networks generally and efficiently is developed under the different platform environment such as the different hardware and the different operating system. One of the main problems is that all the agents of the TMN system must be duplicated and maintain the software and the data blocks that perform the identical function. Therefore, the standard of the Q3 interface development cannot be defined and the multi-platform cannot be supported in the development of the TMN agent. In order to overcome these problems, the Farming methodology that is based on the Farmer model has been suggested. The main concept of the Farming methodology is that the software and the data components that are duplicated and stored in each distributed object are saved in the Platform Independent Class Repository (PICR) by converting into the format of the independent componentware in the platform, so that the componentwares that are essential for the execution can be loaded and used statically or dynamically from PICR as described in the framework of each distributed object. The distributed TMN agent of the personal communication network is designed and developed by using the Farmer model.

The matrix decomposition of transformation associated with the Kronecker product not only provides a thoughtful structure in hardware realization but also bestows a skillful tool for complexity evaluation. Hence, there are several fast algorithms developed to achieve efficient computation of two-dimensional (2-D) discrete cosine transform (DCT) with matrix decomposition techniques. However, we found that their derivations associated with their computation structures were not shown formally. In this paper, we propose formal derivations to remedy their deficiencies to achieve more structural 2-D DCT and inverse DCT (IDCT) algorithms. Furthermore, we also show that the remedied algorithms are with less computational complexity and more regular structure for realization.