Concurrency Control in Advanced Database Applications

Concurrency control has been thoroughly studied in the context of traditional database applications such as banking and airline reservations systems. There are relatively few studies, however, that address the concurrency control issues of advanced database applications such as CAD/CAM and software development environments. The concurrency control requirements in such applications are different from those in conventional database applications; in particular, there is a need to support non-serializable cooperation among users whose transactions are long-lived and interactive, and to integrate concurrency control mechanisms with version and configuration control. This paper outlines the characteristics of data and operations in some advanced database applications, discusses their concurrency control requirements, and surveys the mechanisms proposed to address these requirements

Concurrency Control in Advanced Database Applications

Concurrency control has been thoroughly studied in the context of traditional database applications such as banking and airline reservations systems. There are relatively few studies, however, that address the concurrency control issues of advanced database applications such as CAD/CAM and software development environments. The concurrency control requirements in such applications are different from those in conventional database applications; in particular, there is a need to support non-serializable cooperation among users whose transactions are long-lived and interactive, and to integrate concurrency control mechanisms with version and configuration control. This paper outlines the characteristics of data and operations in some advanced database applications, discusses their concurrency control requirements, and surveys the mechanisms proposed to address these requirements

Distributed IT for integration and communication of engineering information for collaborative building design

In recent years, the rapid development of new information technologies has significantly impacted on the product development process as strategic means to gain competitive advantage in a global market. In the engineering domain, powerful computer-based tools such as Computer Aided Design systems enable engineers to perform various design tasks and realise product concepts in the early phase of the product development process. However, the increasing complexity of modern products as well as the globalization of product development further necessitate distributed and collaborative design environments. This is where different computer systems and dispersed specialists in similar or different disciplines need to collaboratively be involved in shared design activities. Therefore, the integration and communication of engineering information are two of the most key technical factors in ensuring successful collaboration. The current application of information technology in supporting collaboration during the design process is limited to either a document-based or a common format-based exchange level. These methods provide relatively simple forms of collaboration compared with desired distributed and collaborative design environments that can deliver more effective ways of collaboration. The work detailed in this research investigates the advantages of using modern distributed information technologies alongside a suitable framework and a product model to support multi-disciplinary collaborative design. The work also involves exploring other important issues related to real-time collaborative design environments. These are design transaction management, access control, communication, and version management. The research work employs modern technology and distributed computing to enhance the processes of collaborative building design. The research proposes a framework and a product model to extend the functionalities of stand-alone and single-user design systems to facilitate synchronous collaborative design where distributed designers can work concurrently on a centralised shared model and carry out all necessary communication and data exchanges electronically. The implemented framework proposes a data transaction management approach that ensures efficient concurrent access to the model data and maintains data consistency. The framework also employs software agents to automatically access and operate on the information exchanged among the collaborators. The proposed product model in this work extends an adopted model to support access right control and version management. The work is implemented in an experimental software as a client-server model. .Net technology is used for implementing the framework and the product model and virtual reality technology is used to allow for intuitive interaction with the system. The research concludes that the utilisation of the modern distributed technologies can effectively induce change in the design process toward a more collaborative and concurrent design. As demonstrated within this work, these technologies with a suitable system design can meet the main requirements of a real-time collaborative building design system

Distributed IT for integration and communication of engineering information for collaborative building design

In recent years, the rapid development of new information technologies has significantly impacted on the product development process as strategic means to gain competitive advantage in a global market. In the engineering domain, powerful computer-based tools such as Computer Aided Design systems enable engineers to perform various design tasks and realise product concepts in the early phase of the product development process. However, the increasing complexity of modern products as well as the globalization of product development further necessitate distributed and collaborative design environments. This is where different computer systems and dispersed specialists in similar or different disciplines need to collaboratively be involved in shared design activities. Therefore, the integration and communication of engineering information are two of the most key technical factors in ensuring successful collaboration. The current application of information technology in supporting collaboration during the design process is limited to either a document-based or a common format-based exchange level. These methods provide relatively simple forms of collaboration compared with desired distributed and collaborative design environments that can deliver more effective ways of collaboration. The work detailed in this research investigates the advantages of using modern distributed information technologies alongside a suitable framework and a product model to support multi-disciplinary collaborative design. The work also involves exploring other important issues related to real-time collaborative design environments. These are design transaction management, access control, communication, and version management. The research work employs modern technology and distributed computing to enhance the processes of collaborative building design. The research proposes a framework and a product model to extend the functionalities of stand-alone and single-user design systems to facilitate synchronous collaborative design where distributed designers can work concurrently on a centralised shared model and carry out all necessary communication and data exchanges electronically. The implemented framework proposes a data transaction management approach that ensures efficient concurrent access to the model data and maintains data consistency. The framework also employs software agents to automatically access and operate on the information exchanged among the collaborators. The proposed product model in this work extends an adopted model to support access right control and version management. The work is implemented in an experimental software as a client-server model. .Net technology is used for implementing the framework and the product model and virtual reality technology is used to allow for intuitive interaction with the system. The research concludes that the utilisation of the modern distributed technologies can effectively induce change in the design process toward a more collaborative and concurrent design. As demonstrated within this work, these technologies with a suitable system design can meet the main requirements of a real-time collaborative building design system

Coupling engineering workstations to a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster 01 workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Empirical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail

Processing and transaction concepts for cooperation of engineering workstations and a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster of workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Emperical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail