Showing papers on "Wait-for graph published in 1995"

Method for learning data processing rules from graph information

Abstract: A learning method for performing a method of inductively learning rules from machine data, and a method for analyzing an inference process to learn rules useful for increasing efficiency by a common program are provided. Data desired to be classified is converted into a graph and is then input. The course of process by a computer is also converted into a graph and is then input. Then, patterns appearing in the input graph are extracted and patterns having a good evaluation result are output. The patterns are converted into rules for classification and rules for high-speed operation in accordance with a kind of the input graph, and are output.

Graph-Theoretical Methods to Construct Entity-Relationship Databases

Abstract: Within the recent years, the entity-relationship approach has become one of the most popular methods in high-level database design. In this approach data are modelled as entity and relationship types. Usually relationship types come along with certain restrictions that influence the structure of databases. Cardinality constraints are the most commonly used class of constraints used to model such restrictions. Database instances satisfying given cardinality constraints are said to be valid. The aim of this paper is to show how to use methods from graph theory to determine the class cardinalities of entity and relationship types in valid databases. We develop algorithms for this purpose and a number of variations of the problem, namely to construct databases of minimum size and linear ternary databases.

GD-Workbench: A System for Prototyping and Testing Graph Drawing Algorithms

Abstract: We present a tool for quick prototyping and testing graph drawing algorithms. The user interacts with the system through a diagrammatic interface. Algorithms are visually displayed as directed paths in a graph. The user can specify an algorithm by suitably combining the edges of a path. The implementation exploits the powerful functionalities of Diagram Server and has been experimented both as a research support tool and as a back-end of an industrial application.

Relational Set Theory

Abstract: This article presents a relational formalization of axiomatic set theory, including so-called ZFC and the anti-foundation axiom (AFA) due to P Aczel The relational framework of set theory provides a general methodology for the fundamental study on computer and information sciences such as theory of graph transformation, situation semantics and analysis of knowledge dynamics in distributed systems To demonstrate the feasibility of relational set theory some fundamental theorems of set theory, for example, Cantor-Bernstein-Schroder theorem, Cantor's theorem, Rieger's theorem and Mostowski's collapsing lemma are proved

Deadlocks in distributed systems: request models and definitions

Abstract: The paper addresses the problem of deadlock detection in asynchronous distributed systems for system model that covers unspecified receptions and non-FIFO channels. It presents a hierarchy of deadlock models considered till now, and then abstracts away their differences to define a single, general deadlock model. This general model is used to introduce abstract formulation of basic deadlock detection problems, and to specify distributed algorithm which uniformly addresses deadlock detection problem for various request models. Finally, in this context, termination detection problem is also considered.

Non-blocking concurrency control in distributed database systems

Abstract: Concurrency control based on conventional techniques requires additional efforts for deadlock detection and elimination. The possibility of a deadlock is also connected to the introduction of delays, and repeated restarts of transactions in deadlock cycles. In the proposed approach, a technique for generation of data flow precedence graphs among transactions at data sites has been studied. The local access graph approach is a fully distributed approach. Through local computations, the approach can prevent deadlocks in a distributed system. >

A distributed deadlock detection and resolution algorithm based on a hybrid wait-for graph and probe generation scheme

Abstract: We present a continuous deadlock detection and resolution algorithm in distributed database systems. Our algorithm maintains an augmented transaction wait-for graph at each site and uses a modified priority-based probe generation scheme in order to detect local deadlocks without transmitting any intra-site deadlock detection messages, to minimize the number of inter-site messages sent for detection of global deadlocks and also for the early detection of global deadlocks that might occur in the future without transmitting detection messages repeatedly. The augmented transaction wait-for graph contains, in addition to lock-wait information, information about message-wait relationships among agents of a transaction, probes received from other sites and transitive wait-for relationships among transactions. Global deadlocks are declared whenever a transitive wait-for relationship from an agent of a global transaction is constructed for some agent of the transaction.

Process specification generation from communications service specifications

Abstract: This paper proposes an algorithm for generating process specifications from communications service specifications described by a graph grammar. In this work, it is assumed that a communications system consists of homogeneous processes and that there is no global database. Processes that share a relationship form a global state, and a communications service defines global state transitions caused by inputs to the processes. A global state is represented by a labeled directed graph and a global state transition is described by a graph replacement rule. A process specification is regarded as a distributed algorithm whose purpose is to achieve the global state transitions described by the graph replacement rules. The communication time complexity of the generated distributed algorithm does not depend on the number of graph replacement rules.