Keisuke Bekki

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.

Notes on poles and convergence rate of autoregressive model

The convergence rate of the power spectral density function and the properties of the poles of the AR model as an approximate representation of an ARMA(2,1) process are studied with full use of numerical analysis of specific examples. Attention is focused on the case where the ARMA(2,1) model transfer function in z -1 (time shift operator) has two real system poles 1/r1, 1/r2 and the system zero 1/b in the z -1-plane (complex-plane) with the relationship . When the AR model fitting is applied for the theoretical covariance sequence of the process based on the Levinson-Durbin Algorithm, (1) the convergence rate of power spectrum of the AR model is asymptotically proportional to b, (2) the pole 1/r1 is transferred into the AR model as a real pole, however, the information about 1/r2 merges into all poles of the AR model, and (3) the zero 1/b is equivalently represented in the AR model by a set of poles almost equally spaced on a circle centered at the origin in the complex plane. For the qualitative analysi...

Notes on poles of autoregressive type model. Part III. General case

Abstract Pole locations of a multivariate autoregressive (AR) type model for a Gaussian Markovian process are examined by using the Rouches theorem. The formalism of the previous papers by the authors (J. Math. Anal. Appl. 124, 1987, 98–116; 123, 1987, 480–493) is generalized. It is shown that when the order of the AR type model becomes large, poles of the AR type model can be classified into three types: (1) poles distributing almost equally spaced on circles which are centered at the origin with radiuses equal to the absolute value of zeros, (2) system poles inside the smallest circle, and (3) robust and non-robust singular poles which were introduced in the papers referenced above.

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.

Application of Assurance Technology for Railway Signaling System

The railway signaling system has recently achieved realization of new functions by using assurance technology. By constructing systems in stages, making both control data and information data coexist on the same network, and realizing coexistence of both old and new systems, we succeeded in introducing a large-scale system as well as system change. This method also improved services to customers such as a decrease in train delay and continuation of train operation. Assurance technology can now be applied not only to systems in which we have already used this technology in systemization, but also to many other railway systems. On the other hand, when we try to change a complex and large-scale system, it is difficult to do so in order to accommodate new needs with completely new functions, since the new system will be affected by the existing system. We reviewed ways to solve this problem by using assurance technology

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.

An automatic finite state machine synthesis using temporal logic decomposition

Since conventional methods to synthesize a finite state machine (FSM) assign binary codes to all the nonredundant states, they do not exploit delay latches which are sometimes effective in simplifying machine structure. The authors propose a novel method to synthesize an FSM by applying a time shift operation on both inputs and outputs of the FSM. Therefore, the FSM is decomposed into a smaller-scale FSM and two combinational logic circuits including the delay latches. One of the combinational logic circuits is attached to the input part of the FSM and the other is attached to its output part. The algorithm is evaluated for several benchmark examples of FSMs, from which it is concluded that the FSM can be synthesized with 5% less hardware by applying the proposed algorithm.<<ETX>>

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.