We analyze the behavior of a finite FIFO buffer in an advanced packet-switched network. It is modeled by a multi-class single-server delay-loss system Σχi MAP i/ PH /1/m. As stochastic process of the system it yields a finite Markov chain with QBD structure and two boundary sets. Our main result is a new representation of its steady-state vector in terms of a linear combination of exactly two matrix-geometric components. Furthermore, we present an efficient algorithm to solve the corresponding matrix-quadratic equations. As second key result we state a new efficient recursive procedure to calculate the congestion characteristics of this delay-loss system.

In this paper, we propose a transformation technique for the multiplications of one variable with multiple constants, which are frequently seen in the various applications of signal processing, image processing, and so forth. The method is based on the exploration of common subexpressions among constants and reduces the number of shifts, additions, and subtractions to implement linear computations with hardware. Our method searches for regularity among elements of a linear transform using matrix decomposition and generates a reduced data-flow graph which preserves the full regularity. We show experimental results obtained using Discrete Cosine Transform (DCT) and Fast Fourier Transform (FFT) and illustrate the effectiveness of the method.

It is well known that M-ary/spread spectrum (M-ary/SS) system is superior to direct-sequence spread spectrum system under AWGN, and can achieve high spectral efficiency. On the other hand, however, the main drawback of this system is that the synchronization acquisition is difficult. In this paper, we propose a new synchronization acquisition method of M-ary/SS system. This method acquires the code synchronization by introducing a symmetrical property in spreading sequences, and detecting this property with the differential decoding technique. As spreading sequences, a set of orthogonal sequences and a set of non-orthogonal sequences are considered. The strong features of proposed systems are that the systems can acquire the code synchronization in carrier band and can reduce the complexity of calculation greatly. Among the comparison results of the systems with newly proposed orthogonal and some specific non-orthogonal spreading sequences, it is especially noted that the latter can reduce the mean acquisition time and calculation complexity much greater than the former.

In this paper, we illustrate the analysis of microstrip structures with a large number of unknowns using the sparse-matrix/canonical grid method. This fast Fourier thansform (FFT) based iterative method reduces both CPU time and computer storage memory requirements. We employ the Mixed-Potential Integral Equation (MPIE) formulation in conjunction with the RWG triangular discretization. The required spatial-domain Green's functions are obtained efficiently and accurately using the Complex Image Method (CIM). The impedance matrix is decomposed into a sparse matrix which corresponds to near interactions and its complementary matrix which corresponds to far interactions among the subsectional current elements on the microstrip structures. During the iterative process, the near-interaction portion of the matrix -vector multiplication is computed directly as the conventional MPIE formulation. The far-interaction portion of the matrix-vector multiplication is computed indirectly using fast Fourier transforms (FFTs). This is achieved by a Taylor series expansion of the Green's function about the grid points of a uniformly-spaced canonical grid overlaying the triangular discretization.

A method for recovering the LPC spectrum from a microphone array input signal corrupted by less directional ambient noise is proposed. This method is based on the subspace method, in which directional signal and non-directional noise is classified in the subspace domain using eigenvalue analysis of the spatial correlation matrix. In this paper, the coherent subspace (CSS) method, a broadband extension of the subspace method, is employed. The advantage of this method is that is requires a much smaller number of averages in the time domain for estimating subspace, suitable feature for frame processing such as speech recognition. To enhance the performance of noise reduction, elimination of noise-dominant subspace using projection is further proposed, which is effective when the SNR is low and classification of noise and signals using eigenvalue analysis is difficult.

For the completely polarized wave case, this paper presents the explicit formulae of the characteristic polarization states in the co-polarized radar channel, from which one can obtain the CO-POL Max, the CO-POL Saddle and the CO-POL Nulls in the Stokes vector form. Then the problem on the polarimetric contrast optimization is discussed, and the explicit formula of the optimal polarization state for contrast enhancement is presented in the Stokes vector form for the first time. To verify these formulae, we give some numerical examples. The results are completely identical with other authors', which shows the validity of the presented method.

One of the polarimetric radar applications is classification or identification of targets making use of the scattering matrix. This paper presents a decomposition scheme of a scattering matrix into three elementary scattering matrices in the circular polarization basis. The elementary components are a sphere, a diplane (dihedral corner reflector), and a helix. Since a synthetic aperture FM-CW radar provides scattering matrix through a polarimetric measurement, this decomposition scheme was applied to the actual raw data, although the matrix is resulted from a swept frequency measurement. Radar imaging experiments at the Ku band (14.5-15.5GHz) were carried out to obtain a total of 6464 scattering matrices in an imaging plane, using flat plates, corner reflectors and wires as elementary radar targets for classification. It is shown that the decomposition scheme has been successfully carried out to distinguish these targets and that the determination of rotation angle of line target is possible if the scattering matrix is classified as a wire.

An extension is made for a set of systems that have a quadratic Lyapunov function in common for the purpose of analysis and design. The nominal set of system matrices comprises stable symmetric matricies, which admit a hyperspherical Lyapunov function. Based on stability robustness results, sets of matrices are constructed so that they share the same Lyapunov function with the nominal ones.

A new numerical technique, termed the method of matrix-order reduction (MMOR), is developed for handling electromagnetic problems in this paper, in which the matrix equation resulted from a method-of-moments analysis is converted either to an eigenvalue equation or to another matrix equation with the matrix order in both cases being much reduced, and also, the accuracy of solution obtained by solving either of above equations is improved by means of a newly proposed generalized Jacobian iteration. As a result, this technique enjoys the advantages of less computational expenses and a relatively good solution accuracy as well. To testify this new technique, a number of wire antennas are examined and the calculated results are compared with those obtained by using the method of moments.

A method is proposed for forming hillock-free aluminum-based alloy bus lines for active-matrix liquid-crystal displays (LCDs). Aluminum (Al)-based alloy films are deposited using an Al target containing boron (B) or nickel (Ni) in a sputtering ambient containing nitrogen. The Al-Ni films deposited using an Al target containing Ni showed excellent hillock resistance: virtually no hillock formation after thermal treatment at around 400 and no significant increase in resistivity. These films also showed good patternability with a simple wet etching: a smooth line edge and a gently tapered profile. These films are thus suitable for the bus lines of active matrices.

The convergence characteristics of the adaptive beamformer with the RLS algorithm are analyzed in this paper. In case of the RLS adaptive beamformer, the convergence characteristics are significantly affected by the spatial characteristics of the signals/noises in the environment. The purpose of this paper is to show how these physical parameters affect the convergence characteristics. In this paper, a typical environment where a few directional noises are accompanied by background noise is assumed, and the influence of each component of the environment is analyzed separately using rank analysis of the correlation matrix. For directional components, the convergence speed is faster for a smaller number of noise sources since the effective rank of the input correlation matrix is reduced. In the presence of background noise, the convergence speed is slowed down due to the increase of the effective rank. However, the convergence speed can be improved by controlling the initial matrix of the RLS algorithm. The latter section of this paper focuses on the physical interpretation of this initial matrix, in an attempt to elucidate the mechanism of the convergence characterisitics.

We propose a novel feeding circuit for a 30 GHz planar multibeam antenna applied to high-speed wireless communication systems. The feeding circuit is a bi-layer 8-port Butler matrix constructed with phase adjusted slot-coupled hybrids and branch-line hybrids. The new circuit configuration eliminates troublesome vias and line crossings, so it can be manufactured by traditional photolithograph. The feeding circuit is designed by using the spectral domain moment method considering bonding film effects. A prototype of a multibeam antenna which has seven pencil-beams with 10 beamwidths is manufactured and tested; the beam scan angle error is less than 3 at 30 GHz.

This paper provides a queueing model analysis of virtual route networks for which a pacing window flow control mechanism is employed with an input queue included. The input queue is introduced into the model to describe the waiting system where messages prevented from entering the network are stored in first-come first-serve manner. Both cases of finite and infinite capacity are considered. The model leads to a Markovian queueing system, which is fully solved through appropriate use of matrix-geometric methods. The empirical rule is that the optimum window size which maximizes the power criterion including the admission delay is nearly twice the number of hops (nodes of the network). Simulations are presented to verify the analytical results. Finally, performance comparisons with the sliding window protocol are made. Our results show that although the average number of messages in the network is higher for the pacing window case, when the input queue delay is taken into consideration the overall performance of the pacing window protocol is better than that of the sliding window.

The author once defined the Ω-matrix and showed that it played an important role for estimating the number of solutions of a resistive circuit containing active elements such as CCCS's. The Ω-matlix is a generalization of the wellknown P-matrix. This paper gives the necessary and sufficient conditions for the Ω-matrix.

M-ary orthogonal keying (MOK) systems under carrier frequency offset (CFO) are investigated. It is shown that spurious signals are introduced by the offset frequency components of spectrum after multiplication in correlation detection process, and some conditions on robust orthogonal signal sets are derived. Walsh function sets are found to be very weak against CFO, since they produce large spurious signals. As robust orthogonal signal sets against CFO, the rows of circulant Hadamard matrices are proposed and their error performanses are evaluated. The results show that they are good M-ary orthogonal signal sets in the presence of CFO.

This paper proposes a new duplication redundancy technology, 2 Transistors for 1.5 Gates, that is capable of automatic defect tolerance, so making large, high-resolution, color TFT-LCD panel fabrication both easy and economical. This redundancy technology with automatic defect tolerant capability has a low hardware overhead and is very capable of compensating for open circuit defects in a large active-matrix panel. This technology was confirmed by fabricating a 9.5-inch color TFT-LCD panel with 640480 pixels(960960 dots). This panel showed excellent display performance and produced pictures without defects. The yield improvement effect of this technology was also confirmed by calculation based on the Boltzmann statistics model. Consequently, this technology is clearly seen to have a yield improvement effect equal to defect density reduction of about one order, compared to non redundancy. This technology drastically reduces dot and line defects, enabling fabrication of large, high-resolution, color TFT-LCD panels at a relatively low cost.

To overcome the problem of narrow viewing angle in active matrix liquid crystal displasy(LCDs) in the twisted nematic mode(TN mode), we have proposed a new LCD mode using a bend-alignment cell with an optical compensator. In this new mode, we have successfully obtained a black state with almost no leakage over a wide viewing angle range with very fast response. We describe the fundamental principle and design rule of the optical compensator and discuss the properties obtained in theoretical and experimental term.

The mesh-connected computers with hyperbus broadcasting are an extension of the mesh-connected computers with multiple broadcasting. Instead of using local buses, we use global buses to connect processors. Such a strategy efficiently reduces the time complexity of the semigroup problem from O(N) to O(log N). Also, the matrix multiplication and the transitive closure problems are solved in O(log N) and O(log2 N) time, respectively. Then, based on these operations, several interesting problems such as the connected recognition problem, the articulation problem, the dominator problem, the bridge problem, the sorting problem, the minimum spanning tree problem and the bipartite graph recognition problem can be solved in the order of polylogarithmic time.

The characteristics of a-Si bottom-gate TFT test devices with several kinds of inorganic "quasi-black matrix," such as metal, semiconductor, and insulator, on the top were investigated for various black matrix(BM) resistivities. In the Ia-Vg characteristics, for a BM sheet resistance of about1 1012 Ω/, a high off current and large Vth shift were observed due to the back-gating effects when the BM is charged up. Accrding to the ac dynamic characteristics, there was almost no leakage due to the capacitive coupling between source and drain after 16.6 msec(one frame) when the BM sheet resistance was above 7 1013 Ω/ . It was found that hydrogenated amorphous silicon germanium(a-SiGe:H) film, which has enough optical density, with the sheet resistance above the order of 1014 Ω/ is a promising candidate for an inorganic BM on TFT array.

In the usual optical flow detection, the gradient constraint, which expresses the relationship between the gradient of the image intensity and its motion, is combined with the least-squares criterion. This criterion means assuming that only the time derivative of the image intensity contains noise. In this paper, we assume that all image derivatives contain noise and derive a new optical flow detection technique. Since this method requires the knowledge about the covariance matrix of the noise, we also discuss a method for its estimation. Our experiments show that the proposed method can compute optical flow more accurately than the conventional method.