Tamotsu Kasai

A Method for the Correction of Garbled Words Based on the Levenshtein Metric

In this paper we propose a new method for correcting garbled words based on Levenshtein distance and weighted Levenshtein distance. We can correct not only substitution errors, but also insertion errors and deletion errors by this method. According to the results of simulation on nearly 1000 high occurrence English words, higher error correcting rates can be achieved by this method than any other method tried to date. Hardware realization of the method is possible, though it is rather complicated.

Synchronization and substitution error-correcting codes for the Levenshtein metric

Block codes are constructed that are capable of simultaneously correcting e or fewer synchronization errors in t consecutive words, for any t \geq 2e + 1 , and s or fewer substitution errors in eachof t - 1 or fewer of these words under the condition that there exists at least one ungarbled word among the t consecutive words. Also, some new extensions of the A_{n}^{c} codes of Calabi and Hartnett are presented under the condition that synchronization and substitution errors do not coexist in the t consecutive words.

Placement of Circuit Modules Using a Graph Space Approach

This paper deals with the problem of automated placement of electronic components in a circuit layout by using a graph-space approach. In this approach, the relationships of connections among modules in a given electronic circuit are represented by a hypergraph. Then by using a graph-space approach, the vertices (representing the modules) are mapped into the graph space such that the distance between vertices in the space reflects the weights (the number of wires) of edges between vertices of the original hypergraph. On the basis of this placement in graph-space, the modules are assigned to grids on the printed-circuit board so as to minimize the total wire length. Simulation results show this technique yields a better assignment than the one derived from a hand-optimized layout and from an accepted automated-design method.

Switched-capacitor non-recursive lowpass filter

A new switched-capacitor realization of a non-recursive filter based on the digital filter theorem is proposed. A switched-capacitor realization of the delay circuit is described first. A switched-capacitor coefficient multiplier and adder are based on the integral feedback capacitance circuit. This circuit has the feature that the voltage across the integral feedback capacitance is used for the output voltage, whereas, in an ordinary circuit, the output voltage is used at the output terminal of an operational amplifier. Agreement between experimental and theoretical values is confirmed.

Switched-capacitor realization of a Walsh transform circuit and its application to sequency filtering

A novel switched-capacitor discrete Walsh transform circuit is proposed. The Walsh hardware transformation is improved in simplicity by using the proposed circuit, and this circuit has a speed advantage because of analog processing. Furthermore, a switched-capacitor inverse Walsh transform circuit is constructed. A switched-capacitor sequence filter is also proposed which combines the Walsh transform circuit and its inverse.<<ETX>>

A consideration of the problems in switched-capacitor realization of non-recursive and recursive filters

ABSTRACT The realizations of switched-capacitor filter based on the digital filter and their problems are indicated. There are two types of filters, non-recursive and recursive. For the switched-capacitor realization of non-recursive, an improvement is given, and for that of recursive, a limitation under the circuit configuration using discrete parts is shown

Sampled-data charge processor

ABSTRACT A general-purpose analogue signal processor is presented in which all operations are performed in a charge domain. The processor can be customized to each application according to an instruction program. The processor is composed of amplifiers, analogue switches, capacitors and a memory. Charge-domain processing techniques and a calibration technique are used to reduce the requirement for a capacitor precision-ratio. An application to bandpass filtering is demonstrated.

The Efficient Use of Buffer Storage

The computer storage consists of a large, slow main storage and a small, fast storage called a buffer, which is integrated into the CPU. A proper management of data in the two storages can satisfy the desire for large and fast memory. The performance of this system is significantly influenced by the hit rate, which is defined as the probability of finding the data wanted for a fetch in buffer storage. This paper discusses an approach of representing the degree of association between variables for a given program and describes an associative assignment of program variables into main storage in order to imp rove the hit rate. As a result of the simulation, this association mehtod provides a good indication of performance.

Binocular Stereograph Based on Structures of Edge‐Arcs

The determination of the matching feature points in the left and the right images is one of the important problems. As one means to cope with this problem, a method has been presented in which the continuous feature points are approximated by edges, and the matching pair is determined by comparing the edge-line structures of the two images. This paper presents a method which handles not only the edge-lines but also the arcs in a similar way as the features of the image

Switched-capacitor discrete Fourier analyser with window function circuit

An analogue window function circuit is realized by using switched-capacitor techniques. In order to verify the effect of this window, a novel switched-capacitor analogue discrete Fourier analyser is proposed. The window function circuit is included in this analyser as the ratios of capacitances. This switched-capacitor discrete Fourier analyser is very simple in construction, namely, only two elemental circuits based on the integral feedback capacitance circuit are connected in series. Agreement between the experimental and the theoretical values is confirmed.