The Structural Active-Object System (SAOS) approach allows rapid development of various concurrent systems by structural and hierarchical object composition (SHOC). We implemented, as a SAOS program, a graphical editing and simulation program for automatic guided vehicle (AGV) systems, which carry around parts in automated factories. It is difficult to predict...
Performance of a reliable storage subsystem for a centralized database system was studied by simulation. The reliable storage subsystem studied consists of three redundant disk units that are updated one at a time from a consistent database state to another consistent database state, Thus, even if a central processor and/or...
An execution of a database system is considered correct if its net effect is as if transactions were executed serially, and such an execution is called serializable. In this short paper we show that the serializability test problem can be reduced to a simple pebbling problem. Our characterization is intuitive...
A theory for resiliency control of distributed database systems is developed, and schemes that preserve the consistent global database state in the presence of site crashes and message link failures are discussed. The schemes can at least theoretically be paired with any concurrency control scheme that produces y-serializable executions. Further,...
It is highly desirable for a distributed database system to achieve logically continuous operation even if some sites or message links fail. In this paper, we describe a scheme that can automatically reconfigure a fully-replicated distributed database system upon subsystem failures. The scheme can tolerate total failures of some sites....
A typical database system maintains target data, which contain information useful for users, and access path data, which facilitate faster accesses to target data. Further, most large database systems support concurrent processing of multiple transactions. For a static database system model, where units of concurrency control are not dynamically created...
In this short paper, we present an implementation method for a distributed commit/ termination protocol for a distributed database system. The protocol, which handles both commit and termination processing of distributed transactions, is represented by communicating Moore machines. Several advantages of our approach are discussed.
A concurrency and resiliency control scheme for a distributed database system with replicated data is discussed. The scheme, true-copy token scheme, uses true-copy tokens in order to designate the physical data copies (true copies) that can be identified with the current logical data that are globally unique, and then it...
In a manufacturing system, machines, robots and storage areas are used as serially-reusable resources. If the usage of these resources is not properly controlled, deadlocks may occur. In this paper, we present a simple deadlock prevention method for a linear manufacturing line. Our deadlock prevention method can be implemented simply...
A modern computerized manufacturing control system must manage production data, coordinate control actions, and provide user-friendly interfaces. An actionbase management system (ABMS) is a general software system that facilitates implementations of actionbase systems that provide these capabilities for different applications. Besides an ordinary data management facility, our ABMS includes action...