Kazuo Kera

Phased-in construction method of ATOS

ATOS (Autonomous Decentralized Transport Operation Control System) is a high density railway transport management system of an unprecedented scale. The system has been continuously built up in stages after the online operation of its first station commenced in 1994 and successfully operating since then. In this paper we will discuss phased-in construction techniques by line system. We intend to demonstrate the results of our proving examination of the proposed technology using practical examples. We will also discuss new requirements emerged as the result of improvements made in the network infrastructure for information systems such as information terminals and the extension method thereof. This system, now operating with first and second lines, may be termed the largest of such systems to implement the autonomous decentralization system technology.

Autonomous Decentralized Traffic Management System

The Autonomous Decentralized Traffic Management System is a completely renovated rail traffic control system, which is quite different from the conventional CTC (centralized traffic control)/PRC (programmed route control) type system. The features of the system are fully automatic route control for large-scale stations, a maintenance-work management system and an advanced man-machine system for dispatchers to adjust a disturbed diagram quickly. The system also has a flexible system construction and is expandable. These features are achieved by using autonomous decentralized system technology. This system was developed for ATOS (Autonomous decentralized Transport Operation control System) in the Tokyo metropolitan area, which is a high-density railway line section. The Autonomous Decentralized Traffic Management System was also applied to COSMOS (COmputerized Safety Maintenance and Operation system of Shinkansen) on the Shinkansen line sections of the East Japan Railway Company. These systems have been smoothly operated since the start of system operations.

High assurance step-by-step autonomous construction technique for large real time system

The recent large real time systems have the needs of growing systems including heterogeneous functions and operations. High assurance systems are very important for such systems. In order to realize the high assurance systems, we research the step-by-step system construction technique with assurance technology. In this paper we propose the functional reliability and the online functional availability as the best index to indicate the assurance property for step-by-step construction. According to the new index, the best solution for the step-by-step construction is the construction pattern to put the large functional units into online at first, and to put the small functional units into online gradually.

Assurance technologies for growing systems and their application to large-scale transport operation control systems

Recently, system needs of growing large-scale systems including heterogeneous functions and operations are increased. An assurance system that achieves high reliability and high availability is very important for such systems. In order to realize an assurance system, we developed the assurance technology based on ADS (Autonomous Decentralized System). When a growing large-scale system changes or grows, its reliability may be lowered. We clarify the risk factors which lower the reliability and quality of a growing system when the system is modified. We then examine the methods to eliminate or ease those risk factors, and propose adaptable assurance technology that can minimize the risk under restrictive conditions such as cost, resource, periods, etc. We also describe ATOS as an example that has applied the assurance technique and its effectiveness as a really changing and growing system.

Autonomous successive construction technology without stopping system operation for real-time system

Recent large real time systems have required system expandability with heterogeneous functions and operations. A high assurance system is very important for such systems. In order to realize a high assurance system, we research autonomous successive construction technology without stopping system operation for real time systems. This technology is also called step-by-step system construction. In this paper we propose functional reliability and online functional availability as the best index to indicate assurance performance for system construction. According to this new index, the best solution for system construction is a construction pattern to put large subsystems online at first, and to put small subsystems online gradually. Moreover we propose the importance rating as an index to determine online input sequence.

Step-by-step system construction technique with assurance technology-evaluation measure for step-by-step system constructioni

Recently the system needs of growing systems including heterogeneous functions and operations have increased. An assurance system that achieves high reliability and high availability is very important for such systems. In order to realize a high assurance system, we researched the step-by-step construction technique with assurance technology. In this paper we mainly discuss the evaluated measure for step-by-step construction. Functional reliability and online functional availability are the best measures for deciding the order of step-by-step system construction. According to the measure, functional group construction is the best solution.

Assurance technology for large transport operation control system

The recent large transport operation control system with a long construction period has the needs of step-by-step system construction. Therefore, an assurance point of view is necessary for the system construction. We mention assurance evaluation based step-by-step construction technology, data filtering for online protection, and operation mode management. In addition, we show the effectiveness of the assurance technology through simulation and actual application for transport operation control systems.

Assurance technology for Tokyo Metropolitan Railway Network

System needs of growing systems including heterogeneous functions and operations are increased. High assurance system that achieves high reliability and high availability is very important for such systems. In order to realize high assurance system, we developed the assurance technology based on ADS (Autonomous Decentralized System). When a growing system changes or grows, its reliability may be lowered. In this paper, we clarify the risk factors which lower the reliability and quality of a growing system when the system is modified. We will then examine the technology to eliminate or mitigate those risk factors, and propose adaptive assurance technology that can minimize the risk. We also applied this technology to ATOS (Autonomous Decentralized Transport Operation Control System) for Tokyo Metropolitan Railway Network as an example of really changing and growing system and mention its effectiveness.

High assurance system for tokyo metropolitan area railway network

L Introduction Large-scale public systems in today’s information control field require. that seveml conditions should be satisfied. Fmt, a phased-in construction of the system must be possible so that the system can be constructed over a long period of time. Second the system must be flexible and be adapted to meet the changes of social needs. All such systems are assumed to constantly grow, expand and change. We must modify the system in order to grow it; however, its reliability may be reduced by every modiftcation. In the case of a conventional system where it is assumed that there will be no growth, reliability is assured if the system is reliable when introduced. On the other hand, a growing system has the major problem of stable operation without reduction of reliability even as it is routinely modd the technology it uses is called asSuratl~ technology. 2. High-Assurance System Technology Autonomous Decentralimd System (ADS) architecture has been used mainly to realize high assumce computer systems in control systems field. Information Technology has developed remarkably in recent years, and the systems have many high functions. For example, a control system supplies not only conventional control function, but also various information se-vies and other heterogeneous functions. For such gmwing large-scale system in which heterogeneous functions co-exist, the mechanism to protect mutual violation from each other should be mpired. And the mechanism to minimize the effects to the existing functions should be necessary. Furthermore the mechanism to protect online system from test