Hiroshi Inose

A unity bit coding method by negative feedback

Signal-to-noise performances of a unity bit coding method and the characteristics of an experimental video encoder based upon the principle are described. The system contains a signal integration process in addition to the original delta modulator and features capability of transmitting dc component of input signal. The characteristics of the quantizing noise to the signal frequency, the signal amplitude and the integrator time constant are obtained theoretically as well as experimentally. The characteristics of periodical noise which are inherent to the proposed system are also investigated. The design and the characteristics of an experimental encoder for digital transmission of video signals are described as examples of the experimental equipment constructed to demonstrate the realizability of the principle. The experimental results show that considerably good reproduction of video pictures is obtained with sampling frequency as low as 30 Mc and suggest that the proposed system well fulfills the purpose.

Theoretical aspects in the analysis and synthesis of packet communication networks

With the intention of outlining some of the theoretical studies on the design of packet communication networks the present paper introduces the models and the basic relations underlying the analysis as well as the method for evaluating packet delay. Then the multicommodity flow problem as applied to the route assignment is described with particular reference to static and quasi-static routing schemes. Following this topological design methods are described in terms of capacity assignment, flow assignment, capacity and flow assignment, and topology, capacity and flow assignment. Theoritical studies on such factors as flow control and error control that affect the network throughput are also outlined together with the theoretical aspects on packet radio, satellite, and radio systems.

Road-traffic control with the particular reference to Tokyo traffic control and surveillance system

Traffic signals were first introduced for reasons of safety by providing the right of way to the intersecting traffic in a fixed sequence. It was soon found, however, that a signalized intersection could be used more efficiently by properly timing the traffic light in accordance with the amount of incoming traffic. Further improvement in efficiency was then achieved by coordinating the timing of the traffic signals along a traffic artery. With the advent of computer technology, coordination of signal timing is now extended to cover the two-dimensionally distributed traffic signals in such a way that the timing adaptively follows to the changes of the traffic pattern in the area. Information from a large number of traffic detectors are now automatically collected, processed, and fed to the centrally located wall-map displays as well as to the remote roadside displays to provide the traffic officers and the drivers with such information as congestion, accident, frozen surface, etc. This paper outlines the problems, methods, and principles of the road-traffic control and describes the state of the art with reference to the Tokyo Traffic Control and Surveillance System. Some of the results of floating car surveys, the accident statistics as well as the estimated reduction in exhaust emission and fuel consumption are also presented.

A comparative study of the mode of domestic and transborder information flows including data

Abstract Information flow for point to point communications is carried by means of mail, telegram, telex. facsimile, telephone and data communications. The amount of information carried by these media was analyzed for Japanese and U.S. domestic communications, as well as for U.S.-Japan transpacific communications. The total domestic and international information flows are found to be closely related with the gross domestic product (GDP) and the gross international trade, respectively. The effects of technological innovation, service inauguration and regulatory events on the change of information flow are also found.

Local digital telephone system on two-way cable television

Abstract A telephone transmission system using several 6 MHz video bands and return channels in a cable TV distribution line is proposed. In this system, cable TV is used for subscriber accomodation with a local telephone system. In order to realize high accomodation capability in a conventional tree-shaped CATV network, we adopt a two-level structure for the voice distribution, and use a distinct media access protocol for each level: the logical loop scheme for the higher, and the polling-selecting scheme for the lower. The design concept of this system has compatibility with any existing CATV installations, and can be flexibly applied to them. Based on the analysis of the accomodation capacity of the above two media access protocols, a CATV local telephone network for a medium-scale local switch is designed. This system is expected to give one of the most economical subscriber distribution capabilities with integrated telephone and video service.

Description and verification of protocol by temporal logic

When a new communication protocol is formulated, some method for protocol description and verification must be employed to describe and verify that protocol. This paper proposes a protocol description method based on McDermotts temporal logic. The features/characteristics of this method include: (1) The ability to describe “event” and “changes of fact” as they occur; (2) Its temporal logic is suitable for description of continuous time element as well as timeout; and (3) Its temporal logic is effective in protocol verification. A canonical form for protocol description is introduced that enables the translation of any logical inference expression into the standard form. The effectiveness of the proposed method is demonstrated by performing the description and verification of Stennings protocol.

Challenges for policy of network oriented society a Japanese view

Abstract Social impacts of digital information networks are described in terms of convergence of service modes, integration of socioeconomic activities, change in industrial structure, strengthening social infrastructure and enrichment of culture, with some reference to specific Japanese situations. Emphasis is placed on such issues as reorganization of regulatory measures, interoperability of systems and services, communities of interest, privacy and security, freedom of information, information resource development, software production, shift of workforce, societal receptivity, preservation and creation of culture, and lowering of language barriers.

Product validation for standardized network protocol

To connect a new node to an established computer network, it is needed to confirm that the new node is constructed conforming to the network protocol. This paper describes a method to validate the protocol of the product based on an automaton model. The node to be tested is connected to protocol tester which applies a test sequence and observes the response from the node. Considering the fact that protocols are specified in terms of the responses to inputs from higher level as well as external inputs, to validate the protocol for input from higher level, an additional higher level program called validation task may be needed. This paper describes two method for validation of HDLC-BA protocol. The first method uses the validation task and the second method does not use the validation task. Detail of test sequence and the completeness of the validation are described in this paper.

ICCC 78: A retrospection

Abstract This paper summarizes the program planning activities of ICCC-78 and presents the major highlights of the technical program.