The main objective of this paper is to propose a new top-down subcube allocation scheme which has complete subcube recognition capability with quick response time. The proposed subcube allocation scheme, called Heuristic Subcube Allocation (HSA) strategy, is based on a heuristic and undirected graph, called Subcube (SC)-graph, whose vertices represent the free subcubes, and edge represents inter-relationships between free subcubes. It helps to reduce the response time and internal/external fragmentation. When a new subcube is released, the higher dimension subcube is generated by the cycle detection in the SC-graph, and the heuristic is used to reduce the allocation time and to maintain the dimension of the free subcube as high as possible. It is theoretically shown that the HSA strategy is not only statically optimal but also it has a complete subcube recognition capability in a dynamic environment. Extensive simulation results show that the HSA strategy improves the performance and significantly reduces the response time compared to the previously proposed schemes.

Hydrogen termination of HF-treated Si surfaces and the oxidation kinetics have been studied by x-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR) Attenuated Total Reflection (ATR). The oxidation of hydrogen-terminated Si in air or in pure water proceeds parallel to the surface presumably from step edges, resulting in the layer-by-layer oxidation. The oxide gryowth rate on an Si(100) surface is faster than (110) and (111) when the wafer is stored in pure water. This is interpreted in terms of the steric hindrance against molecular oxygen penetration throughth the (110) and (111) surfaces where the atom void size is equal to or smaller than O2 molecule. The oxide growth rate in pure water for heavily doped n-type Si is significantly high compared to that of heavily doped p-type Si. This is explained by the conduction electron tunneling from Si to absorbed O2 molecule to form the O2- state. O2- ions easily decompose and induce the surface electric field, enhancing the oxidation rate. It is found that the oxidation of heavily doped n-type Si in pure water is effectively suppressed by adding a small amount (1003600 ppm) of HCl.

Optimal static load balancing problems in open BCMP queueing networks with state-independent arrival and service rates are studied. Their examples include optimal static load balancing in distributed computer systems and static routing in communication networks. We refer to the load balancing policy of minimizing the overall mean response (or sojourn) time of a job as the overall optimal policy. We show the conditions that the solutions of the overall optimal policy satisfy and show that the policy uniquely determines the utilization of each service center, the mean delay for each class and each path class, etc., although the solution, the utilization for each class, the mean delay for all classes at each service center, etc., may not be unique. Then we give tha linear relations that characterize the set whose elements are the optimal solutions, and discuss the condition wherein the overall optimal policy has a unique solution. In parametric analysis and numerical calculation of optimal values of performance variables we must ensure whether they can be uniquely determined.

This paper treats the problem of realizing high speed 2-D denominator separable digital filters. Partitioning a 2-D data plane into square blocks, filtering proceeds block by block sequentially. A fast intra-block parallel processing method was developed using block state space realization, which allows simultaneous computation of all the next block states and the outputs of one block. As the block state matrix of the filter has high sparsity, the rows and columns are interchanged respectively to reduce the matrix size. The filter is implemented by a multiprocessor system, where for each matrix's row one processor is assigned to perform the row-column vector multiplication. All processors wirk in synchronized fashion. Number of processors of this implementation are equal to the number of rows of the reduced state matrix and throughput is raised with block lengths.

This paper discusses the bit-rate compression of super high definition still images with subband coding. Super high definition (SHD) images with more than 20482048 pixels or resolution are introduced as the next generation imaging system beyond HDTV. In order to develop bit-rate reduction algorithms, an image evaluation system for super high definition images is assembled. Signal characteristics are evaluated and the optimum subband analysis/synthesis system for the SHD images is clarified. A scalar quantization combined with run-length and Huffman coding is introduced as a conventional subband coding algorithm, and its coding performance is evaluated for SHD images. Finally, new coding algorithms based on block Huffman coding and entropy coded vector quantization are proposed. SNR improvement of 0.5 dB and 1.0 dB can be achieved with the proposed block Huffman coding and the vector quantization algorithm, respectively.

We introduce a novel neural network called the T-Model and investigates the learning ability of the T-Model neural network. A learning algorithm based on the least mean square (LMS) algorithm is used to train the T-Model and produces a very good result for the T-Model network. We present simulation results on several practical problems to illustrate the efficiency of the learning techniques. As a result, the T-Model network learns successfully, but the Hopfield model fails to and the T-Model learns much more effectively and more quickly than a multi-layer network.

The two most important parameters in reactive ion etching process, ion bombardment energy and flux, were extracted through a simple RF waveform measurement at the excitation electrode in a conventional cathode-coupled plasma RIE system. By using the extracted plasma parameters, damage and contamination in Si substrates induced by reactive ion etching in a SiCl4 plasma were investigated. A very convenient map representation of ion energy and ion flux was introduced in understanding the etching process occurring in the RIE system.

In this paper, subband image coding with symmetric biorthogonal wavelet filters is studied. In order to implement the symmetric biorthogonal wavelet basis, we use the Laplacian Pyramid Model (LPM) and the trigonometric polynomial solution method. These symmetric biorthogonal wavelet basis are used to form filters in each subband. Also coefficients of the filter are optimized with respect to the coding efficiency. From this optimization, we show that the values of a in the LPM generating kernel have the best coding efficiency in the range of 0.7 to 0.75. We also present an optimal bit allocation method based on considerations of the reconstruction filter characteristics. The step size of each subband uniform quantizer is determined by using this bit allocation method. The coding efficiency of the symmetric biorthogonal wavelet filter is compared with those of other filters: QMF, SSKF and Orthonormal wavelet filter. Simulation results demonstrate that the symmetric biorthogonal wavelet filter is useful as a basic means for image analysis/synthesis filters and can give better coding efficiency than other filters.

This paper proposes an efficient design method of three-dimensional (3-D) recursive digital filters for video signal processing via decomposition of magnitude specifications. A given magnitude specification of a 3-D digital filter is decomposed into specifications of 1-D digital filters with three different (horizontal, vertical, and temporal) directions. This decomposition can reduce design problems of 3-D digital filters to design problems of 1-D digital filters, which can be designed with ease by conventional methods. Consequently, design of 3-D digital filters can be efficiently performed without complicated tests for stability and large amount of computations. In order to process video signal in real time, the 1-D digital filters with temporal direction must be causal, which is not the case in horizontal and vertical directions. Since the proposed method can approximate negative magnitude specifications obtained by the decomposition with causal 1-D R filters, the 1-D digital filters with temporal direction can be causal. Therefore the 3-D digital filters designed by the proposed method is suitable for real time video signal processing. The designed 3-D digital filters have a parallel separable structure having high parallelism, regularity and modularity, and thus is suitable for high-speed VLSI implementation.

Based on the Fornasini-Marchesini second model, an efficient algorithm is developed to derive the characteristic polynomial and the inverse of the system matrix from the state-space parameters. As a result, the external description of the Fornasini-Marchesini second model is clarified. A technique for designing 2-D recursive digital filters in the frequency domain is then presented by using the Fornasini-Marchesini second model. The resulting filter approximates both magnitude and group delay specifications and its stability is always guaranteed. Finally, three design examples are given to illustrate the utility of the proposed technique.

The globalization of business where single products and services are designed, developed, and manufactured in many different countries signals a significant need for cost-effective and reliable information movement and management capabilities. Similarly, consumers are seeking technologies which will allow them to visit the Smithsonian, scan a book in the Oxford Library, and interview a Japanese monk for a school report, all from the comfort of home. A necessary ingredient for realizing this global society is a strong telecommunications infrastructure. Our paper describes some of the customer needs and technology advances that are causing a revolution in planning global telecommunications networks. We present a new telecommunications paradigm and study its impact in two key areas: multi-country network routing at both the traffic and facility levels, and global network robustness.

Plasmaless etching using ClF3 gas has been investigated on nitride films with different composition. For the sputter deposited and thermally grown silicon nitride films containing no hydrogen, the etch rate increases and the activation energy decreases with increase of the composition ratio of silicon to nitrogen between 0.75 and 1.3. This fact indicates that the etching is likely to proceed through the reaction between Si and ClF3. The native oxide on the silicon-nitride films can also be removed with ClF3 gas. Ultra-violet light irradiation from a low pressure mercury lamp remarkably accelerates the removal of the native oxide and the etch rate of the thermally grown silicon-nitride films. For the plasma deposited films, the etch rate is strongly accelerate with increasing hydrogen content in the films, but the activation energy hardly depends on the bounded hydrogen in the films, consistent with the results for Si etching.

We present a successful method for designing 2-D circularly symmetric R lowpass filters with constant group delay. The procedure is based on a transformation of a 1-D prototype R filter with constant group delay, whose magnitude response is the 2-D cross-sectional response. The 2-D filter transfer function has a separable denominator and a numerator which is obtained from the prototype numerator by means of a series of McClellan transformations whose free parameters can be optimized by successive procedure. The method is illustrated by an example.

For the development of a practical device simulation, it is necessary to solve the large sparse linear equations with a high speed computation of direct solution method. The use of parallel computation methods to solve the linear equations can reduce the CPU time greatly. The Multi Step Diakoptics (MSD) algorithm, is proposed as one of these parallel computation methods with direct solution, which is based on Diakoptics, that is, a tearing-based parallel computation method for sparse linear equations. We have applied the MSD algorithm to device simulation. This letter describes the partition and connection schedules in the MSD algorithm. The evaluation of this algorithm is done using a massively parallel computer with distributed memory (AP1000).

This paper designs and evaluates highly parallel VLSI processors for real time 2-D state-space digital filters using hierarchical behavioral description language and synthesizer. The architecture of the 2-D state-space digital filtering system is a linear systolic array of homogeneous VLSI processors, each of which consists of eight processing elements (PEs) executing 1-D state-space digital filtering with multi-input and multi-output. Hierarchical behavioral description language and synthesizer are adopted to design and evaluate PE's and the VLSI processors. One 16 bit fixed-point PE executing a (4, 4)-th order 2-D state-space digital filtering is described on the basis of distributed arithmetic in about 1,200 steps by the description language and is composed of 15 K gates in terms of 2 input NAND gate. One VLSI processor which is a cascade connection of eight PEs is composed of 129 K gates and can be integrated into one 1515 [mm2] VLSI chip using 1 µm CMOS standard cell. The 2-D state-space digital filtering system composed of 128 VLSI processors at 25 MHz clock can execute a 1,0241,024 image in 1.47 [msec] and thus can be applied to real-time conventional video signal processing.

This paper proposes design schemes which obtain an efficient spare-channel assignment against single and double link failures for a self-healing network. Spare-channel design problems can be formulated as a linear-programming (LP) problem when variables are assumed to be continuous. For the problem, the proposed algorithm effectively solves a sub-set of whole constraints by making use of a maximum-flow algorithm in an iterative manner. It is shown that the maximum number of iteration times is limited by the number of links in the network. Moreover, the relation between the design function and the self-healing function is discussed. It is also shown that the cooperation of the two functions can realize more effective control in large scale networks.

The establishment of an intelligent network service operation architecture is important for facilitating development and integration of service operation systems. To do this, the basic concepts and goals of service operation items must first be clarified. Then, the necessary procedures as well as the required data on the behaviors of customers, operators and operation systems must be described. These various points are discussed based on an operation study methodology.

This paper describes the application of a neural network to the optimal routing problem in broadband multimedia networks, where the objective is to maximize network utilization while considering the performance required for each call. In a multimedia environment, the performance required for each call is different, and an optimal path must be found whenever a call arrives. A neural network is appropriate for the computation of an optimal path, as it provides real-time solutions to difficult optimization problems. We formulated optimal routing based on the Hop field neural network model, and evaluated the basic behavior of neural networks. This evaluation confirmed the validity of the neural network formulation, which has a small computation time even if there are many nodes. This characteristic is especially suitable for a large-scale system. In addition, we performed a computer simulation of the proposed routing scheme and compared it with conventional alternate routing schemes. The results show the benefit of neural networks for the routing problem, as our scheme always balances the network load and attains high network utilization.

In this paper, a new description of a separable-denominator (S-D) two-dimensional (2-D) transfer matrix is proposed, and its realization is considered. Some of this problem had been considered for the transfer matrices whose elements are two-variables rational functions. We shall propose a 2-D transfer matrix whose inputs-outputs relation is represented by a ratio of two-variables polynomial matrices, and present an algorithm to obtain a 2-D state-space model from it. Next, it is shown that the description proposed in this paper is always minimally realizable. And, we shall present a method of obtaining the description proposed in this paper from a S-D 2-D rational transfer matrix.

This paper describes a super high definition (SHD) image processing system we have developed. The computing engine of this system is a parallel processing system with 128 processing elements called NOVI- HiPIPE. A new pipelined vector processor is introduced as a backend processor of each processing element in order to meet the great computing power required by SHD image processing. This pipelined vector processor can achieve 120 MFLOPS. The 128 pipelined vector processors installed in NOVI- HiPIPE yield a total system peak performance of 15 GFLOPS. The SHD image processing system consists of an SHD image scanner, and SHD image storage node, a full color printer, a film recorder, NOVI- HiPIPE, and a Super Frame Memory. The Super Frame Memory can display a ful color moving image sequence at a rate of 60 fps on a CRT monitor at a resolution of 2048 by 2048 pixels. Workstations, interconnected through an Ethernet, are used to control these units, and SHD image data can be easily transfered among the units. NOVI- HiPIPE has a frame memory which can display SHD still images on a color monitor, therefore, one processed frame can be directly displayed. We are developing SHD image processing algorithms and parallel processing methodologies using this system.