In this paper stochastic aradient adaptive filters using the Sign or Sign-Sign Algorithm are analyzed based upon general assumptions on the reference signal, additive noise and particularly jointly distributed tap errors. A set of difference equations for calculating the convergence process of the mean and covariance of the tap errors is derived with integrals involving characteristic function and its derivative of the tap error distribution. Examples of echo canceller convergence with jointly Gaussian distributed tap errors show an excellent agreement between the empirical results and the theory.

In this contribution an algorithm for joint detection in fast frequency hopping/multiple frequency shift keying (FFH/MFSK) multiple access (MA) systems is presented. The new algorithm - referred to as REC algorithm - evaluates ambiguities which occur during the decision process and iteratively reduces the number of candidate symbols. The REC algorithm is of low complexity, suitable for every addressing scheme, and effective for both an interference-only channel and a fading channel. For the interference-only channel the REC algorithm enables maximum likelihood (ML) joint detection with low computational effort.

A very simple but general scheme has been developed to calculate burst error occurrences due to cycle slip in clock recovery on frequency-selective Nakagami-Rice fading channels. The scheme, which we call the "Equivalent Transmission-Path Model," plays a role in connecting "wave propagation" with "digital transmission characteristics" in a general manner. First computer simulations assuming various types of delay profiles identify the "key parameters in Nakagami-Rice fading" that principally dominate the occurrence of cycle slips. Following this a simple method is developed to calculate the occurrence frequency of cycle slips utilizing the nature of the key parameters. Then, the accuracy of the scheme is confirmed through comparison between calculated values and simulation results. Finally, based on the scheme, calculated results on cycleslip occurrences are presented in line-of-sight fading environments.

The polymer matrix for the number of N in-puts/outputs, N stages and 2x2-switches is denoted as the 1-D Spanke-Benes (SB) network. Throughout the paper, the 1-D SB-network, which equals the diamond cellular array, is extended to arbitrary dimensions by a mathematical transformation (a 1-D network provides the interconnection of 1-D data). This transformation determines the multistage architecture completely by providing size, location, geometry and wiring of the switches as well as it preserves properties of the networks, e.g., the capability of sorting. The SB-networks of dimension 3 are analysed and sorting is applied.

A subclass of context-free languages, called pure context-free languages, which is generated by context-free grammar with only one type of symbol (i.e., terminals and nonterminals are not distinguished), is introduced and the problem of identifying from positive data a restricted class of monogenic pure context-free languages (mono-PCF languages, in short) is investigated. The class of mono-PCF languages is incomparable to the class of regular languages. In this paper we show that the class of mono-PCF languages is polynomial time identifiable from positive data. That is, there is an algorithm that, given a mono-PCF language L, identifies from positive data, a grammar generating L, called a monogenic pure context-free grammar (mono-PCF grammar, in short) satisfying the property that the time for updating a conjecture is bounded by O(N3), where N is the sum of lengths of all positive data provided. This is in contrast with another result in this paper that the class of PCF languages is not identifiable in the limit from positive data.

We found a novel connecting orbit in the averaged Duffing-Rayleigh equation. The orbit starts from an unstable manifold of a saddle type equilibrium point and reaches to a stable manifold of a node type equilibrium. Although the connecting orbit is structurally stable in terms of the conventional definition of structural stability, it is structually unstable since a one-deimensional manifold into which the connecting orbit flows is unstable. We can consider the orbit is one of global bifurcations governing the differentiability of the closed orbit.

This paper presents the device technology for monolithic integration of InP-based resonant tunneling diodes (RTDs) and high electron mobility transistors (HEMTs). The potential of this technology for applications in quantum functional devices and circuits is demonstrated in two integration schemes in which RTDs and FETs are integrated either in Parallel or in series. Based on the parallel integration scheme, we demonstrate an integrated device which exhibits negative differential resistance and modulated peak current. This integrated device forms the foundation of a new category of functional circuits featuring clocked supply voltage. Based on the series integration scheme, resonant-tunneling high electron mobility transistors (RTHEMTs) with novel current-voltage characteristics and useful circuit applications are demonstrated. The high-frequency characteristics of RTHEMTs are also reported.

For reduction of computational complexity in the IA algorithm, the thinned-out IA algorithm in which only one step size is updated every iteration is proposed and is complementarily switched with the HA algorithm according to the convergence. The switching is determined by using the gradient of the error signal power. These are investigated through the computer simulations.

We studied the application of precursor solutions that can be fired into oxides to form a protective layer for AC-type Plasma Display Panel (AC-PDP). Our study of alkoxide and metallic soap as MgO precursors revealed that the crystallinity of MgO films depends on the starting substance. Since the electric discharge characteristics of a panel and the lamination effect of the protective layer depend on precursors, it was confirmed that binders having higher crystallinity provide better characteristics. Our study revealed that a compound-oxide film has high crystallinity. The application of a Ba0.6Sr0.4Gd2O4 formation solution to a binder and the application of a Sr0.6Mg0.4Gd2O4 formation solution to a protective layer both are seemed promising We also found that a double-layer film, made by forming a protective layer of fine MgO powder and a Ba0.6Sr0.4Gd2O4 binder, on top of a protective layer made of fine MgO powder and a MgO binder, provides a luminous efficiency 5.3 times higher than that of sputtered MgO film which is one of candidates for the large panel, and the conventional electron beam evaporation is not suitable for the large panel. We further found that a triple-layer protective film made by forming a thin film of Sr0.6Mg0.4Gd2O4 provides low voltages of 1 V in firing voltage (Vf) and 35 V in sustaining voltage (Vs) compared to the double-layer film and provides a luminous efficiency 5.5 times higher than that of sputtered MgO film. A life test revealed the triple-layer film in particular providing a useful life of more than 10,000 hours. From these findings, we concluded that the compound-oxides which is composed of alkaline-earth-metal and rare-earth-element could be applied effectively to a protective layer for AC-PDP.

For high frequency video signals, display monitors for personal computers are required to shift from the horizontal scanning frequency fH=15.75 kHz for conventional TV broadcasting to fH=64 to 80 kHz, which is called XGA. Shifting to high frequencies and restrictions on the withstand voltage of horizontal transistors decrease the inductance of deflection yokes, which is an obstacle in manufacturing deflection yokes. A study was undertaken on an operation to permit deflection/high voltage integrated operation while keeping the inductance of the deflection yoke high. This paper reports the results.

In this paper, we propose a camera calibration method that estimates both intrinsic parameters (perspective and distortion) and extrinsic parameters (rotational and translational). All camera parameters can be determined from one or more images of planar pattern consists of parallelogramatic grid points. As far as the pattern can be visible, the relative relations between camera and patterns are arbitrary. So, we have only to prepare a pattern, and take one or more images changing the relative relation between camera and the pattern, arbitrarily; neither solid object of ground truth nor precise z-stage are required. Moreover, constraint conditions that are imposed on rotational parameters are explicitly satisfied; no intermediate parameter that connected several actual camera parameters are used. Taking account of the conflicting fact that the amount of distortion is small in the neighborhood of the image center, and that small image has poor clues of 3-D information, we adopt iterative procedure. The best parameters are searched changing the size and number of parallelograms selected from grid points. The procedure of the iteration is as follows: The perspective parameters are estimated from the shape of parallelogram by nonlinear optimizations. The rotational parameters are calculated from the shape of parallelogram. The translational parameters are estimated from the size of parallelogram by least squares method. Then, the distortion parameters are estimated using all grid points by least squares method. The computer simulation demonstrates the efficiency of the proposed method. And the results of the implementation using real images are also shown.

The paper deals with Kleenean functions defined as fuzzy logic functions with constants. Kleenean functions provide a means of handling conditions of indeterminate truth value (ambiguous states) which ordinary classical logic (binary logic) cannot cope with. This paper clarifies a necessary and sufficient condition for a function to be a Kleenean function. The condition is provided with a set of two conditions, and it will be shown that they are independent of each other.

A new prediction method for the effective address is presented. This method works with the buffer named the address prediction buffer, and allows the data cache to be accessed speculatively. As a consequence of the trend toward increasing clock frequency, the internal cache is no longer able to fill the speed gap between the processor and the external memory, and the data cache latency degrades the processor performance. In order to hide this latency, the prediction method is proposed. By this method, the load address is predicted, and the data is fetched earlier than the memory access stage. In the case that the prediction is correct, the latency is hidden. Even if the prediction is incorrect, the performance is not degraded by any miss penalties. We have found that the prediction accuracy is 81.9% on average, and thus the performance is improved by 6.6% on average and a maximum of 12.1% for the integer programs.

In this paper, a new two-level flow control scheme using VP credit-based control and stop-and-go rate control for Asynchronous Transfer Mode (ATM) networks is presented. Since the proposed scheme does not require any information on traffic characteristics, we propose to apply such a flow control scheme to the best effort traffic that requires no band-width guarantee from the network. The proposed flow control scheme can efficiently use the leftover bandwidth after the guaranteed traffic has been satisfied. Therefore, high bandwidth utilization can be achieved. Furthermore, cell loss can completely be avoided by the lower-level credit-flow control done on a per VP basis. On top of this, a higher-level Explicit Congestion Notification (ECN) rate control is employed to avoid any performance degradation. Simulations have been performed to verify the effectiveness of the proposed scheme. It is found that the average end-to-end delay of our proposed scheme is better than that of the original VCFC scheme [1]. In addition, there is also a tremendous saving in the memory required when compared with the VCFC scheme.

This paper concerns a Petri-net-based model for describing reactive and concurrent systems. Although many high-level Petri nets have been proposed, they are insufficiently practical to describe reactive and concurrent systems in the detail modeling, design and implementation phases. They are mainly intended to describe concurrent systems in the rough modeling phase and lack in several important features (e.g., concurrent tasks, task communication/synchronization, I/O interface, task scheduling) which the most actual implementations of reactive and concurrent systems have. Therefore it is impossible to simulate and analyze the systems accurately without explicitly modeling these features. On the other hand, programming languages based on Petri nets are deeply dependent on their execution environments and not sophisticated as modeling and specification languages. This paper proposes MENDEL net which is a high-level Petri net extended by incorporating concurrent tasks, task communication/synchronization, I/O interface, and task scheduling in a sophisticated manner. MENDEL nets are a wide-spectrum modeling language, that is, they are suitable for not only modeling but also designing and implementing reactive and concurrent systems.

A circularly polarized omnidirectional antenna consisting of a vertical sleeve dipole and three pairs of titled parasitic elements set around it is proposed. The antenna is useful to mobile communication because the use of circular polarization allows us to suppress the effect of multi-path reflection waves (inverse rotation) caused by building walls and surface of the ground. The antenna with an omnidirectional pattern has a simple structure without a feeding network for radiating circular polarization. To understand the radiation characteristics of the proposed antenna, an approximation theory using the induced electromotive force method is introduced. As an example, using a fixed spacing of a quarter wave-length between the vertical dipole and the parasitic elements, the possibility of generation of circular polarization is examined. Then the computational results of the axial ratio and the input impedance are compared with the results of the numerical analysis using the moment method and the experimental result. The radiation characteristics of the antenna can be understood by using the approximation theory introduced here. As a summary of the study, the contour map of the axial ratio of circular polarization is depicted using the moment method. For practical design of this antenna, a small correction factor should be multiplied to the calculated results. From the experimental results, the proposed antenna has a gain of 2 dBi and 3 dB band-width with an axial ratio of about 8%.

We present an extended quarter-plane lattice model for generating two-dimensional (2-D) autoregressive fields. This work is a generalization of the extended lattice filter of diagonal form (ELDF) developed by Ertuzun et al. The proposed model represents a wider class of 2-D AR fields than conventional lattice models. Several examples are presented to demonstrate the applicability of the proposed model. Furthermore, the proposed structure is compared with other conventional lattice filters based on the computation of their entropy values.

Optical Frequency Division Multiplexing (OFDM) is an attractive multiplexing approach for exploiting optical communication technology. Although considerable progress has been made in this approach, it still suffers from numerous potential impairments, stemming from several phenomena. (i.e., laser unstability, residual temperature variations, linear and nonlinear cross talk.). Conventional serial coding technique is not practical in lightwave systems, as it changes the system's bit rate that is not desirable. In this paper a new Parallel Coded Optical Multicarrier Frequency Division Multiplexing (PCOM-FDM) technique has been investigated. The strategy of multicarriers, together with Parallel Forward Error Control (PFEC) coding, is a potentially novel approach as in this approach we have, 1) Investigated optical multicarrier communication that is effective in combating dispersion and increasing throughput, 2) Proposed PFEC coding which is different from conventional serial coding in respect that it does not change the system bit rate per carrier and prevents the effects of channel wandering. It is highly desirable in lightwave systems and thus holds a vital importance in practical high speed optical communication systems. Theoretical treatment shows that the proposed approach is promising and practical.

Hybrid image coding method is one of the most promising methods for efficient coding of moving images. The method makes use of jointly motion-compensated prediction and orthogonal transform like DCT. This type of coding scheme was adopted in several world standards such as H.261 and MPEG in ITU-T and ISO as a basic framework [1], [2]. Most of the work done in motion-compensated prediction has been based on a block matching method. However, when input moving images include complicated motion like rotation or enlargement, it often causes block distortion in decoded images, especially in the case of very low bit-rate image coding. Recently, as one way of solving this problem, some motion-compensated prediction methods based on an affine transform or bilinear transform were developed [3]-[8]. These methods, however, cannot always express the appearance of the motion in the image plane, which is projected plane form 3-D space to a 2-D plane, since the perspective transform is usually assumed. Also, a motion-compensation method using a perspective transform was discussed in Ref, [6]. Since the motion detection method is defined as an extension of the block matching method, it can not always detect motion parameters accurately when compared to gradient-based motion detection. In this paper, we propose a new motion-compensated prediction method for coding of moving images, especially for very low bit-rate image coding such as less than 64 kbit/s. The proposed method is based on a perspective transform and the constraint principle for the temporal and spatial gradients of pixel value, and complicated motion in the image plane including rotation and enlargement based on camera zooming can also be detected theoretically in addition to translational motion. A computer simulation was performed using moving test images, and the resulting predicted images were compared with conventional methods such as the block matching method using the criteria of SNR and entropy. The results showed that SNR and entropy of the proposed method are better than those of conventional methods. Also, the proposed method was applied to very low bit-rate image coding at 16 kbit/s, and was compared with a conventional method, H.261. The resulting SNR and decoded images in the proposed method were better than those of H.261. We conclude that the proposed method is effective as a motion-compensated prediction method.

To make the model-based coding a practical method, new signal processing techniques other than fully-automatic image recognition should be studied. Also after having realized the model-based coding, another new signal processing technique to improve the performance of the model-based coding should be studied. Moreover non-coding functions related to the model-based coding can be embedded as additional features. The authors are studying the interactive model-based coding in order to achieve its practical realization, improve its performance and extend related non-coding functions. We have already proposed the basic concept of interactive model-based coding and presented an eyeglasses processing for a facial image with glasses to remove the frame for improving the model-based coding performance. In this paper, we focus on the 3-D motion detection algorithm in the interactive model-based coding. Previous works were mainly based on iterative methods to solve non-linear equations. A new motion detection algorithm is developed for interactive model-based coding. It is linear because the interactive operation generates more information and the environment of the applications limits the range of parameters. The depth parameter is first obtained by the fact that a line segment is invariant as to 3-D space transformation. Relation of distance between two points is utilized. The number of conditions is larger than that of the unknown variables, which allows to use least square method for obtaining stable solutions in the environment of the applications. Experiments are carried out using the proposed motion detection method and input noise problems are removed. Synthesized wireframe modified by eight parameters provides smooth and natural motion.