Theoretically, corresponding pairs of feature points between two stereo images can determine their 3-D locations uniquely by triangulation. In the presence of noise, however, corresponding feature points may not satisfy the epipolar equation exactly, so we must first correct the corresponding pairs so as to satisfy the epipolar equation. In this paper, we present an optimal correction method based on a statistical model of image noise. Our method allows us to evaluate the magnitude of image noise a posteriori and compute the covariance matrix of each of the reconstructed 3-D points. We demonstrate the effectiveness of our method by doing numerical simulation and real-image experiments.

Dynamic Programming based elastic pattern matching method called Branched Reference Rubber String Matching was investigated. As in Rubber String Matching, the reference pattern is represented as a sequence of direction specified vectors and the input pattern as two dimensional dot pattern. In order to improve the coping of topological variations in input pattern, the reference patterns allow partial pattern alternatives and misses. Effect on the recognition time is almost negligible. Experimental results show the effectiveness of the proposed algorithm.

A new algorithm for multiple-precision modular multiplication is proposed. It is fast and uses a small amount of main memory, and hence, is useful for application of a public-key cryptosystem to small computers, such as card computers.

Coherent and incoherent electromagnetic (EM) waves scattered by many particles are approximately expressed as solutions of integral equations by unconventional multiple scattering method. The particles are randomly displaced from a uniformly ordered distribution, and hence the distribution of particles can change from total uniformity to complete randomness. The approximate expressions of the EM waves are systematically given, independent of the distributions of particles, on the following assumptions. First the particles are identical in material, shape, size and orientation. Second each random displacement of particles from the ordered positions is statistically independent of each other and homogeneous in space. These assumptions may be extended to more general ones but have been used here to make clear the derivation process of the coherent and incoherent EM waves. The approximate expressions of the EM waves are reduced to known ones for both limiting cases: a periodic distribution and a very sparse random distribution. The effective dielectric constant of a random medium containing randomly distributed dielectric spheres can be calculated from the coherent EM wave and compared with those given by conventional methods such as the quasi-crystalline approximation, using the previous results. The comparison indicates the advantage of the method presented here. The present method is expected to be useful for the study of interaction of EM waves with many particles.

In this work, a statistical analysis is performed for a simple constrained high-order Yule-Walker (YW) tone frequency estimator obtained from the first equation of the constrained high-order YW equations. Explicit expressions for its estimation bias and variance are efficiently derived by virtue of a Taylor series expansion technique. Especially, being explicit in terms of frequency, data length and Signal-to-Noise Ratio (SNR) value, the resulting bias expression can not be obtained by using the asymptotic analyses used for the parameter estimation methods. The obtained expressions are compared with their counterparts of the Pisarenko tone frequency estimator. Simulations are performed to support the theoretical results.

The integration of both real-time systems and fault-tolerant systems has been emerged as one of the greatest challenges of this decade. It is called a responsive system, which has the objective to optimeze both timeliness and reliability. The performance measure in responsive systems is responsiveness that tells how probable a system executes correctly on time with faults occurred. While there have been some achievements in communication protocols and specification, we believe that scheduling problems in responsive systems are not understood deeply and sufficiently, yet. In this paper, we discuss the scheduling problem in responsive systems. At first, we investigate the issues in the scheduling and propose the precise definition of the responsiveness. We also suggest a scheduling algorithm called Responsive Earliest Deadline First (REDF) for preemptive aperiodic tasks in a uniprocessor system. We show that REDF is optimal to obtain the maximum responsiveness, and the time complexity is analyzed to be (N 2N). By illustrating a contradictory example, it is shown that REDF can be enhanced if a constraint on tasks is released.

On a simple model, the quality of the security tag is simulated theoretically and experimentally. A simple correction makes both results correspond exactly and a simulation formula is provided. By using novel insulating film, a small-sized tag of high quality is developed.

We investigate a three-waveguide tapered velocity coupler which consists of a uniform linear, tapered linear and tapered nonlinear slab waveguide. The coupling characteristics depending on the gap width between the waveguides and sloping angle of the tapered waveguides are analyzed by means of the finite difference method. The numerical results show that with realistic structural parameters flat output power characteristics can be obtained over a wide range of input power. It is found that it is possible to use the present structure as a power limiter.

In this paper, we propose a register file with data bypassing function. This register file bypasses data using data bypassing units instead of functional units when actual operation in functional units such as ALU is unnecessary. Applying this method to a general purpose microprocessor with benchmark programs, we demonstrate 50% power consumption reduction in functional units. Though length of bus lines increases a little due to an additional hardware in register file, as buses are not driven when data is bypassed, power consumption in bus lines is also reduced by 40% compared with the conventional architecture.

In this paper, we propose algorithm of deterministic nonlinear prediction, or a modified version of the method of analogues which was originally proposed by E.N. Lorenz (J. Atom. Sci., 26, 636-646, 1969), and apply it to the artificial time series data produced from nonlinear dynamical systems and further corrupted by superimposed observational noise. The prediction performance of the present method are investigated by calculating correlation coefficients, root mean square errors and signature errors and compared with the prediction algorithm of local linear approximation method. As a result, it is shown that the prediction performance of the proposed method are better than those of the local linear approximation especially in case that the amount of noise is large.

In this paper a priori estimation method is presented for calculating solution of convex optimization problems (COP) with some equality and/or inequality constraints by so-called Newton type homotopy method. The homotopy method is known as an efficient algorithm which can always calculate solution of nonlinear equations under a certain mild condition. Although, in general, it is difficult to estimate a priori computational complexity of calculating solution by the homotopy method. In the presented papers, a sufficient condition is considered for linear homotopy, under which an upper bound of the complexity can be estimated a priori. For the condition it is seen that Urabe type convergence theorem plays an important role. In this paper, by introducing the results, it is shown that under a certain condition a global minimum of COP can be always calculated, and that computational complexity of the calculation can be a priori estimated. Suitability of the estimation for analysing COP is also discussed.

The controllability and the stability of the blood clotting system are examined with the linear system analysis. The dynamic behavior of the clotting system consisting of a cascade of ten proteolytic reactions of the clotting factors with multiple positive feed back and feed forward loops is represented by the rate equations in a system of non linear ordinary differential equations with 35 variables. The time courses of concentration change in every factor are revealed by numerical integration of the rate equations. Linearization of the rate equations based on the dynamic behavior of the chemical species relevant to the nonlinear terms leads to the linear systems analysis of the clotting system to clarify the essential features of blood coagulation. It follows from the analysis that the clotting system is uncontrollable regardless of changes in any system parameters and control input and that all the chemical species of the system are uncontrollable so that the sequential reactions in the cascade proceed irreversibly, once they are activated. More over by the analysis of the eigen values, the clotting reaction as a total system was shown to be unstable which was insensitive to changes in the system parameters. These characteristic natures of clotting system must be derived in the sequential cascade reaction pattern and the inherent multiple positive feed back and feed forward regulation.

We present a 44 matrix-based analysis of scattering form a two-dimensional rectangular resistive plane gratings placed on an anisotropic dielectric slab. The solution procedure used is formulated by extending the 44 matrix approach. The fields are expanded in terms of two-dimensional Floquet modes. Total fields can be given as sum of primary and secondary fields whose expression are obtained through eigenvalue problem of coupled wave matrix. Unknown currents on resistive patches are determined by applying Galerkin's method to the resistive boundary condition on resistive grating. Results are compared with other numerical examples available in the literature for isotropic cases. Further, numerical calculation are performed in the case of gratings with polar-type anisotropic slab.

The concept of a new visual communication environment is proposed. The proposed system is a shared and interactive multi-user virtual space that consists of a CG-based virtual space structure and video-based objects. Human interface design issues are discussed from the view point of creating a new reality for enhanced communication.

We present both numerical and approximate calculations to estimate the total harmonic distortion of demodulated signal from the PLL which has an excess phase shift or some time delay in the loop. Values by the two calculation methods are in agreement with results of the appropriate experiment.

We consider the identification of a class of systems which are both time-varying and nonlinear. Time-varying nonlinear systems are often encountered in practice, but tend to be avoided due to the difficulties that arise in modelling and estimation. We study a particular time-varying polynomial model, which is a member of the class of time-varying Wiener models. The model can characterise both time-variation and nonlinearity in a straightforward manner, without requiring an excessively large number of coefficients. We formulate a procedure to find least-squares estimates of the model coefficients. An advantage of the approach is that systems with rapidly changing dynamics can be characterised. In addition, we do not require that the input is stationary or Gaussian. The approach is validated with an application to an automobile modelling problem, where a time-varying nonlinear model is seen to more accurately characterise the system than a time-invariant nonlinear one.

A uniquely decodable code (C1, C2, C3) is investigated for the three-user binary adder channel. The uniquely decodable code is constructed as follows: If C1 is an (n, k) linear code with a generator matrix, C2 is a coset of C1 and C3 is a set of all coset leaders, then the code (C1, C2, C3) is uniquely decodable and its total rate is equal to 1k/n, n2k. This code is easily decodable.

This paper describes 950 GHz power performance of double-doped AlGaAs/InGaAs/AlGaAs heterojunction field-effect transistors (HJFET) operated at a drain bias voltage ranging from 2.5 to 3.5 V. The developed 1.0 µm gatelength HJFET exhibited a maximum drain current (Imax) of 500 mA/mm, a transconductance (gm) of 300 mS/mm, and a gate-to-drain breakdown voltage of 11 V. Operated at 3.0 V, a 17.5 mm gate periphery HJFET showed 1.4 W Pout and -50.3 dBc adjacent channel leakage power at a 50 kHz off-carrier frequency from 950 MHz with 50% PAE. Harmonic balance simulations revealed that the flat gm characteristics of the HJFET with respect to gate bias voltage are effective to suppress intermodulation distortion under large signal operation. The developed HJFET has great potential for small-sized digital cellular power applications operated at a low DC supply voltage.

A data-base for data compression is universal if in its construction no prior knowledge of the source distribution is assumed and is optimal if, when we encode the reference index of the data-base, its encoding rate achieves the optimal encoding rate for any given source: in the noiseless case the entropy rate and in the semifaithful case the rate-distortion function of the source. In the present paper, we construct a universal data-base for all stationary ergodic sources, and prove the optimality of the thus constructed data-base for two typical methods of referring to the data-base: one is a block-shift type reference and the other is a single-shift type reference.

This paper is concerned with the evaluation of the block error probability Pic of a block modulation code for closest coset decoding over an AWGN channel. In most cases, the conventional union bound on Pic for closest coset decoding is loose not only at low signal-to-noise ratios but at relatively high signal-to-noise ratios. In this paper, we introduce a new upper bound on the probability of union of events by using the graph theory and we derive an improved upper bound on Pic for some block modulation codes using closest coset decoding over an AWGN channel. We show that the new bound is better than the conventional union bound especially at relatively high signal-to-noise ratios.