A negation-limited circuit is a combinational circuit which includes at most [log(n1)] NOT gates. We show a relationship between the size of negation-limited circuits computing clique functions and the number of NOT gates in the circuits.

In this letter an SR-latch circuit using Hopfield neural networks is introduced. An energy function suited for a neural SR-latch circuit is defined for which the global convergence is guaranteed. We also demonstrate how to compose master-slave (M/S) SR- and JK-flip flops of novel SR-latch circuits, and further an asynchronous binary counter of M/S JK-flip flops. Computer simulations are included to illustrate how each presented circuit operates.

We present a new multi-layer over-the-cell channel router for standard cell layout design using simulated annealing. This new approach, STANZA-M consists of two key features. The first key feature of our router is a new scheme for simulated annealing in which we use a cost function to evaluate both the total net-length and the channel heights, and an effective simulated annealing process by a limited range to obtain an optimal chnnel wiring in practical time. The second feature of our router is a basic layer assignment procedure in which we assign all horizontal wiring inside a channel to feasible layers by considering the height of channel including cell region with a one dimensional channel compaction process. We implemented our three-layer cannel router in C language on a Solbourne Series 5 Work Station (22 MIPS). Experimental results for benchmarks such as Deutsch's Difficult Example and MCNC's PRIMARY1 channel routing problems indicate that STANZA-M can achieve superior results compared to the conventional routers, and the process times are very fast despite the use of simulated annealing.

Considering the trend towards adopting high efficiency picture coding schemes into digital broadcasting services, we investigate objective picture quality scales for evaluating digitally encoded still and moving pictures. First, the study on the objective picture quality scale for high definition still pictures coded by the JPEG scheme is summarized. This scale is derived from consideration of the following distortion factors; 1) weighted noise by the spatial frequency characteristics and masking effects of human vision, 2) block distortion, and 3) mosquito noise. Next, an objective picture quality scale for motion pictures of standard television coded by the hybrid DCT scheme is studied. In addition to the above distortion factors, the temporal frequency characteristics of vision are also considered. Furthermore, considering that all of these distortions vary over time in motion pictures, methods for determining a single objective picture quality value for this time varying distortion are examined. As a result, generally applicable objective picture quality scale is obtained that correlates extremely well with subjective picture quality scale for both still and motion pictures, irrespective of the contents of the pictures. Having an objective scale facilitates automated picture quality evaluation and control.

A novel effective channel length extraction method has been developed, which utilizes the difference between the local threshold voltage of channel region and that of external region. In this method, the dependence of external resistance on Vg is taken into account, and it is not necessary to extract Vth. It is found that the external resistance can be approximated as the linear function of Vg with Vg around Vth. For a 0.4 µm gate length LDD MOSFET, the accuracy and resolution are estimated to be less than 0.02 µm and 0.003 µm, respectively.

In a hybrid coder which employs motion compensation and discrete cosine transform (MC-DCT coder), up to 90% of bits are used to represent the quantized DCT blocks. So it is most important to represent them with as few bits as possible. In this paper, we propose an efficient method for encoding the quantized DCT blocks of motion compensated prediction (MCP) errors, which adaptively selects one of a few scanning patterns. The scanning pattern selection of an MCP error block is based on the motion compensated images which are always available at the decoder as well as at the encoder. No overhead information for the scanning patterns needs to be transmitted. Simulation results show that the average bit rate reduction amounts to 5%.

When a new digital broadcasting system is introduced for the viewers, it is important to be able to include new services and system aspects. That is to give the viewers new experiences and meet the demands they might have in the future. To fulfil the viewers expectations, is a key for success for the introduction of new service and product. It is equally important to look at the long term perspective and have the possibility to gradually develop the digital broadcasting systems we establish today. A fully integrated multimedia system is a hybrid of different media services, distribution paths and display object. The pros and cons of each of them must be examined and each of them used where best suited. This will probably give a more complex media world with fuzzy borders between what is broadcasting, packaged media and what is the on-line information society. In order to balance this, any new digital multimedia system needs to be developed with an open architecture, based on generally agreed standards and possibly follow a non-proprietary approach. IDUN, a prototype system for multimedia broadcasting, is on its way to fulfil these requirements. IDUN combines the powerful point to multi-point emission, domestic data storage and computer processing with the telecommunication network. It is feasible to introduce it in the analogue world of today but could better be utilised in a fully digital future. Some possible services are further proposed. Some of them with a tight relation to what a broadcaster already produces, which could give an evolutionary transfer to the new digital world.

Video compression technologies such as MPEG have enabled the efficient use of video data in the computer environment. However, the compressed video information still has a huge amount of data compared with the other media such as text, audio, and graphics. Therefore, it is very important to handle the video information in a networked database for the efficient use of resources like storage media. Furthermore, in the networked database, its retrieval methods including search and delivery become the key issues especially for the video information which requires a large network bandwidth. In this paper, a video browsing method using an automatic fast scene cut detection for networked video database access is described. The scene cut is defined as the scene change frame and is detected by temporal change in interframe luminance difference and chrominance correlation which are obtained from spatio-temporally scaled image directly extracted from the MPEG compressed video without any complex processing of video decoding. The detected scene change frames are further investigated to exploit the relationship between the scene cuts and are classified in order to make a hierarchical indexing. These results of detection are stored as an scene index file using the MPEG format. The simulation results are also presented for several test video sequences to show that these methods have enabled the efficient video database construction and accessing.

A multi-stage noise-shaping (MASH) A/D converter combining an RC-integrator and a digital correction technique for high accuracy is described. Using 1.2-µm BiCMOS technology, we developed an A/D converter for digital audio with an S/N ratio of over 100 dB. This paper discusses the principles of MASH technology with an RC-integrator, the technique for correcting RC variation, and the experimental results obtained with a fabricated chip.

Throughout the paper, the nearest-neighbour (NN) interconnection of switches within a multistage interconnection network (MIN) is analysed. Three main results are obtained: (1) The switch preserving transformation of a 2-D MIN into the 1-D MIN (and vice versa) (2) The rearrangeability of the MIN and (3) The number of stages (NS) for the rearrangeable nonblocking interconnection. The analysis is extended to any dimension of the interconnected data set. The topological equivalence between 1-D MINs with NN interconnections (NN-MINs) and 1-D cellular arrays is shown.

Binary sequences with good correlation properties are required for a variety of engineering applications. We previously proposed simple methods to generate binary sequences based on chaotic nonlinear maps. In this paper, statistical properties of chaotic binary sequences generated by Chebyshev maps are discussed. We explicitly evaluate the correlation functions by means of the ensemble–average technique based on the Perron–Frobenius (P–F) operator. As a consequence, we can confirm an important role of the P–F operator in evaluating statistics of chaos by means of the ensemble-average technique.

In this paper, a novel coupler-type wavelength demultiplexer composed of the K+-ion diffused waveguides, which has an adjustment function for optimizing the diffusion depth, is proposed to achieve reliably the high extinction ratio. The optimization in the diffusion depth is made by repeating the K+-ion diffusion and extinction-ratio measurement alternatively, and the high extinction ratios more than 20 dB are measured reliably at both operation wavelengths of 0.6328 and 0.83 µm. Experimental results on the polarization dependence in the extinction-ratio adjustment are also reported.

Precise measurements of temperature dependence of the Andreev reflection current for the N–I–S junctions were carried out. Au and Pb were used as N (normal metal) and S (superconducting material), respectively. The experimental results agreed with the analyses based on the Arnold theory.

Numerical studies of reaction–diffusion systems which consist of chaotic oscillators are carried out. The Rössler oscillators are used, which are arranged two–dimensionally and coupled by diffusion. Pacemakers where the average periods of the oscillators are artificially changed are set to produce target patterns. It is found that target patterns emerge from pacemakers and grow up as if they were in a regular oscillatory medium. The wavelength of the pattern can be varied and controlled by changing the parameters (size and frequency) of the pacemaker. The behavior of the coupled system depends on the size of the system and the strength of the pacemaker. When the system size is large, the Poincar return maps show that the behavior of the coupled system is not simple and the orbit falls into a high–dimensional attractor, while for a small system the attractor is rather simple and a one–dimensional map is obtained. Moreover, for appropriate strength of pacemakers and for certain sizes of the systems the oscillations become periodic. It is also found that the largest and local Lyapunov exponents of the system are positive and these values are uniformly distributed over the pattern. The values of the exponents are smaller than that of the uncoupled Rössler oscillator; this is due to the fact that the diffusion reduces the exponents and modifies the form of the attractor. We conclude that the large scale patterns can stably exist in the chaotic medium.

Fractal image coding using iterated transformations compresses image data by exploiting the self–similarity of an image. Its compression performance has already been discussed in [2] and several other papers. However the relation between the performance and the self–similarity remains unclear. In this paper, we evaluate fractal coding from the perspective of this relationship.

This letter proposes the method using a filter to suppress the very large noise obstructive to the radio pulsar surveys. This noise suppression filter is constructed from the average of the amplitude spectrum of pulsar signal for each channel. Using this method, the dispersion measure, one of the important parameters in the pulsar surveys, can easily be extracted.

Some qualitative properties of an inductively coupled circuit containing two Josephson junction elements with a dc source are investigated. The system is described by a four–dimensional autonomous differential equation. However, the phase space can be regarded as S1×R3 because the system has a periodicity for the invariant transformation. In this paper, we study the properties of periodic solutions winding around S1 as a bifurcation problem. Firstly, we analyze equilibria in this system. The bifurcation diagram of equilibria and its topological classification are given. Secondly, the bifurcation diagram of the periodic solutions winding around S1 are calculated by using a suitable Poincar mapping, and some properties of periodic solutions are discussed. From these analyses, we clarify that a periodic solution so–called "caterpillar solution" is observed when the two Josephson junction circuits are weakly coupled.

This paper proposes a new class of unidirectional byte error locating codes, called single symmetric bit error correcting and single unidirectional byte error locating codes, or SEC–SUbEL codes. Here, "byte" denotes a cluster of b bits, where b2. First, the necessary and sufficient conditions of the codes are clarified, and then code construction method is demonstrated. The lower bound on check bit length of the SEC–SUbEL codes is derived. Based on this, the proposed codes are shown to be very efficient in some range of the information length. The code design concept presented for the SEC–SUbEL codes induces the generalized unidirectional byte error locating codes with single symmetric bit error correction capability.

An optimal control theory has been applied to a biological compartment system to show a method to analyze the control principle of biological system represented by compartments. Present theory has been proposed to afford a theoretical back ground and validity for the strategy of drug administration or control of the anesthetic agent in practical medicine. The instantaneous change of the concentration of a given material within a biological system has been expressed by differential equations. Each compartment has been set to be transferred a material from all other compartments and conversely each compartment sends it to all other compartments. The control input was restricted to be one kind. The performance function involved the deviation from the target value, the rate of change in concentration and the amount of the control variables. The biological system was defined to operate optimally only when the performance function has been minimized during a given time period. By the optimal control theory of Pontoriagin, above biological problem has been converted to a mathematical problem and was solved numerically by multiple shooting method. The calculated trajectory of the optimal control has been asymmetric parabolic one with the maximum at its initiation and the minimum at the middle of total reaction time. This pattern has been consistent with that of probable transient change of the concentration of anesthetic agent when it has been inhalated under the most up to date "Rapid Inhalation Induction" method. The optimal trasient change of the concentration at each compartment has beeb affected by the difference in time dependent nature and the magnitude of the transfer rate. Present theory afforded a method to analyze the control strategy of biological system expressed by compartments model and showed an availability for actual clinical medicine. The optimal control principle must be a most adequate one to describe the Homeostasis in biological system.

On ranging system on short distance using spread spectrum, we examine waveform responses to predict the state of electromagnetic waveform propagation while the signal is received after scattered by a target. Then this system and the numerical results are discussed.