A function R(L), named a rate-risk function, is introduced in the field of statistical decision theory. It specifies the minimal permissible rate R at which information about under-lying uncertainties must be conveyed to the decision maker in order to achieve the prescribed value L of the Bayes risk. Fundamental properties are also clarified for the rate-risk function.

This paper given an outline of the general purpose DASDSP (Development Assist System for Digital Signal Processing) which contains 8 DSP (Digital Signal Processor) boards. Each board can select external analog or digital signals and it is possible for DASDSP to perform the distributed processing. This system has a memory board for the purpose of debugging programs running in each DSP.

The paper proposes the Adjacent Channel Interference Rejection (ACIR) method in Binary-PSK (BPSK) and describes its fundamental characteristics confirmed by conducting experiments.

The relationship between the radar reflectivity factor Z and the rainfall rate R was found using a new raindrop-size distribution which has an improved fit to the existing empirical data. The result Z286 R^1.6 is corresponding nearly to the representative relationship Z200 R^1.6 which is frequently assumed in radar meteorology.

Direct modulation characteristics, such as the side mode suppression ratio and the dynamic wavelength shift, of BIG-DBR (Bundle Integrated Guide Distributed Bragg Reflector) lasers were investigated by applying both sinusoidal and pulse-like modulations to two different kinds of samples with 100 µm and 200 µm active region lengths. The higher side mode suppression ratio of more than 30 dB was obtained for the sample with short active region length of 100 µm within all the frequency range up to 2 GHz even under pulse-like modulation, whereas the dynamic wavelength shift became larger than that of longer active region sample.

In order to reduce the threshold current of a GalnAsP/InP surface emitting junction laser, a SiO₂/metal mirror which provied high reflectivity has been introduced. The minimum threshold was reduced down to 18 mA at 77 K which is about a half of the previous case (35 mA). The operating temperature was raised up to 10.

The performances of the instrument for measuring the glossiness of curved surfaces were improved using a fluorescent-lamp, a TV camera, a microcomputer etc.

Variants of multiple chain mean value analysis algorithms are compared. Reiser's example of a communication system model is taken for a case study. Reiser's original comparison table between the exact MVA and Reiser's approximation is incremented by adding the population heuristic and the linearizer algorithm.

Reliability of single-loop networks can be improved using double loops: foward loops advancing to the neighboring node and backward loops hopping by a certain distance. This paper investigates the number of live transmission lines when two computers break in the network, and discusses the tolerant ability to the failures.

An iterative design of constrained recursive digital filters is developed. The designing scheme requires no initial values. The constraints are subjected to degrees of both numerator and denominator, transmission zeros and poles, if any, and passband and stopband shaping. The resulting filter completes a prescribed magnitude of either passband or stopband ripples. The optimality property of the filters is examined in detail with emphasis on specifications. The designing scheme involves the elliptic design as a special case. Illustrative examples are also given.

Recently, many non-traditional applications of Switched-Capacitor circuits have been popularly studied. As one of those applications, we present here a new constructing technique of a Switched-Capacitor Impedance Simulation Circuit (SC-ISC) with unity-gain buffers. Any desired impedance can be obtained by applying this SC-ISC technique. To make up a SC-ISC simply and generally, four kinds of basic constructing Units and two types of feedback circuits are introduced. Furthermore, by applying those Units, an arbitrary transfer function can be easily synthesized. In addition, some algorithms to obtain useful impedances are proposed. Several SC-ISC impedances were experimentally constructed and theoretically analyzed. In particular, some kinds of simple filters and oscillators were made and tested. They were also theoretically analyzed.

This paper describes a series of experiments on spatial frequency adaptation. The adapting stimulus was a vertical square-wave grating which was moved right and left with constant velocity at the back of a stationary vertical slit. By setting the slit width narrower than a half cycle of the grating, adapting stimuli can be confined to only single edges and bars which repeatedly appear in the slit. Even under this slit vision condition, when adapting frequency was low (0.3, 0.5 and 0.75 c/deg), threshold elevations occurred in the same way as without the slit, where several cycles of the adapting grating could be seen. The position of the largest peak in the elevation profile corresponded to the fundamental frequency of the adapting grating, and the second peak always appeared at a frequency higher than 2 c/deg. The second peak corresponds to a higher harmonic frequency in the adapting stimulus and 2 c/deg corresponds to the lowest adaptable frequency of a sustained system.

This paper presents a new approach, based on the conservation law, for analyzing the following single server queueing system with two classes of customers. The arrival process of one class customers is a Poisson process, while that of the other is represented by a renewal process and therefore need not be a Poisson process. Both classes of customers have exponential service time distributions. These queueing models with two input streams are often encountered in communication systems. Utilizing the conservation law, it is shown that for various types of work-conserving queueing disciplines, the mean time in the system for each class of customers can be expressed in teams of the total workload in the system. When the total workload is known, these formulas can be used to obtain numerical solutions for the mean time in the system. The most important result in this approach is that the mean time in the system for each class of customers can be easily computed even when the service rates of both classes of customers are different. This is demonstrated by computing the mean time in the system using the derived formulas. The approximation formulas for the total workload are also presented based on the diffusion approximations, because it is difficult to obtain exact solutions for the total workload except for some special cases. Comparisons of exact and approximate results show that these approximation formulas provide good approximate values.

The scattering of electromagnetic plane waves incident obliquely upon a column of hot electron plasma, which is magnetized in the axial direction and is located in free space, is investigated based on a kinetic model for the plasma. This model takes into account a full thermal effect in the axial direction and includes the first-order thermal effect with respect to the transverse direction. The boundary-value problem is solved for both cases of polarizations of the incident wave, i.e., TM wave and TE wave. The numerical results of the back-scattering cross section, the far-field power pattern, and the albedo of the plasma column are presented for several typical values of plasma parameters. The thermal effect of plasma on the characteristics of scattering and absorption are discussed at length. It is shown that when the frequency of incident wave is close to the electron cyclotron frequency, in the case of high-temperature plasma, the energy of incident wave is strongly absorbed through the process of collisionless absorption.

This paper proposed a method of predicting the cumulative distribution of the desired-to-undesired power ratio from the cumulative distribution of rain rate. It is assumed that the rain rate and the rain attenuation obey the log-normal distributions. The predicted values show a good agreement with the experimental values obtained in a 14.3 GHz rain scatter experiment.

In order to investigate the effects of choke loading on the radiation patterns in a parallel-plate waveguide, and to investigate the feasibility of the boundary element method (abbr. BEM) for an unbounded radiation problem, measured results of an experimental box horn antenna with the aperture dimension being 22.9 mm478 mm, without and with chokes, are compared with the numerical data obtained by BEM. In the experiment, both the aperture field and the far-field radiation patterns were measured. In the former, the aperture field was measured at =12 GHz by a small dipole fed and supported by a thin (3 mm-outer-diameter) coaxial cable, and fairly good agreement between the measured and the BEM solution was obtained. On the other hand, as for the latter, the far-field pattern measurement was done at =8, 10, and 12 GHz in a 30 m test range. The measured radiation patterns of a parallel-plate waveguide loaded with a chock (6.5 mm in depth and 20 mm in width) agree well with the BEM results at wider angles, even at 90 degrees from the antenna radiation axis.

This paper presents a simple algorithm for diagnosis of a graph-theoretical, self-diagnosis model. The algorithm is based on a ranking method. That is, the algorithm uses the analogy between the rule used in the ranking method: the player who was hit more players directly or indirectly should be ranked lower and the rule used in diagnosis : the unit which is identified as faulty by more other units directly or indirectly should be more strongly suspected as faulty. With this algorithm, faulty units are identified from a given syndrome by simple calculation of a matrix. Although another algorithm is proposed whose complexity is less than the algorithm proposed here, this algorithm has the following two features :
(1) Simplicity :
The algorithm uses only the matrix multiplication and further, the matrix is directly obtainable from syndromes. Thus the algorithm can be implemented easily as a computer program.
(2) Universality :
This algorithm can be used not only for self-diagnosis model of PMC type, but for other types of self-diagnosis models including probabilistic model with slight modifications.
These features of the algorithm are investigated for the systems with design D_1t (t1, 2). The modification of the algorithm for the probabilistic self-diagnosis model is also discussed. The approach seems to open a channel between theoretical works of ranking theory in the field of graph theory and syndrome decoding of models in system diagnosis.

A method for stereo matching is presented, in which matching is searched primarily between edge segments of left and right frames using only geometrical features of the edge segments. An edge segment is a piece of a thinned edge curve which is monotonic with respect to the y-coordinate and is defined as a part of an edge curve that is bounded by edge tips, branch points, or points of extremal y-coordinate. To reduce the effect of noise, a composite segment, which is composed of two edge segments and is monotonic with respect to the y-coordinate, is also regarded as the object of matching. Simulation experiments were performed for three indoor scenes. Matching between segments works very well for simple and intermediate complexity scenes, and works fairly well for a considerable complexity scene.

A speech recognition system for continuously spoken Japanese sentences SPEECH YAMANASHI is described. The system has a knowledge source, in which syntactic, semantic and vocabulary knowledge are contained. It can deal with not only simple sentences but also simple complex and compound sentences without any restriction regarding the tasks. Phoneme identification is performed in real time, and after a slight revision the speech sound is represented by a pseudo-phoneme string. In the syntactic knowledge system, all inflections of inflectional words are taken into account. The syntactic analyzer, using a syntactic state transition network, predicts following words and outputs their syntactic interpretations. The semantic knowledge system deals with the meanings of each word, in particular, it deals with case structures for verbs. The semantic knowledge is used for the prediction of following words and construction of a semantic network of input sentences. The systems with vocabularies of 254 and 538 words work for four Japanese fairy tales with 70 [86] and 45 [69] % sentence and block (enclosed by brackets) recognition scores, respectively; and if sentences are spoken phrase by phrase, sentence and phrase recognition scores of 73 and 93 % are obtained for the system with vocabulary of 1,021 words. The system has an additional version, which may be used as a speech input device of a word processor.

Body surface potential mapping has been shown to improve the diagnostic accuracy of certain cardiac electrophysiological disorders. In order to display heart potential distribution maps dynamically in color graphic, we have developed a high-speed data acquisition and presentation system based on double parallel processing technique. The data presentation system consists of 16 parallel computer boards. Each board includes a local CPU and arithmetic processing unit (APU). Double parallel processing can be accomplished between the local CPU and APU in each processing board. By applying this double parallel processing technique we can achieve a dynamical display of heat potential distribution maps with good precision. Clinical application of this electrocardiographic mapping system should significantly increase the understanding of certain heart diseases. These double parallel computations may be adapted for use in other fields of computer graphics.