W. Cheung. The Model-assisted Global Query System. Ph.D. Thesis, Computer Science Department, Rensselaer Polytechnic Institute, Troy, NY, 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....columns and tables, the knowledge base itself is no longer used in the processing. In contrast, the domain model in SIMS is an integral part of the system, and allows it to combine information sources dynamically and in novel ways. The model assisted global querying (MGQS) approach presented by [Cheung, 1991] shares 26 with SIMS the goal of providing users with access to multiple heterogeneous databases while hiding from them the details of the underlying sources of data. MGQS, like SIMS, uses a model (a metadatabase in their terminology) to describe the contents, organization, and data management ....

W. Cheung. The Model-assisted Global Query System. Ph.D. Thesis, Computer Science Department, Rensselaer Polytechnic Institute, Troy, NY, 1991.

....these metadata concepts. In comparison, virtually all other results in the field fall either in the category of information modeling (level one plus aspects of level two) ANS 85, FUL 92, PAT 92, SOW 91] or in multiple databases management (level 3 plus aspects of level 2 see [BAB 93, BOU 91, CHE 91, SHE 90] for some analyses and surveys) The value of such an integrated solution for the enterprise information integration problems is sufficiently documented in the metadatabase literature. TSER alone, as a meta modeling method, offers an implementationproven compactness if not ....

....information and facilitates the integration of local systems. Therefore, the metadatabase becomes a data instance level meta model not only to support CASE tools and other passive metadata applications, but also to effect functionalities needed in global query processing and systems interactions [CHE 91, HSU 92] The development of this generic metadatabase schema is fully reported in [HSU 91] In a nutshell, the schema follows directly from Figure 3 and contains all three classes of views (application, functional, and structural) plus resources views, in all enterprise models and the logical ....

[Article contains additional citation context not shown here]

W. Cheung, "The Model-Assisted Global Query System," unpublished Ph.D. Thesis - Decision Sciences and Engineering Systems, Rensselaer Polytechnic Institute, November 1991.

....Manifold is based simply on minimizing the number of different sources. In SIMS, source selection is integrated into query access planning, so SIMS will attempt to minimize the overall cost of a query and not just the number of sources accessed. The Model assisted Global Querying System (MGQS) [7] shares with SIMS the goal of providing users with access to multiple heterogeneous databases while insulating them from the details of the underlying sources of data. MGQS, like SIMS, uses a model (a metadatabase in their terminology) to describe the contents, organization, and data management ....

Waiman Cheung. The Model-assisted Global Query System. PhD thesis, Computer Science Department, Rensselaer Polytechnic Institute, Troy, NY, 1991.

....Manifold is based simply on minimizing the number of different sources. In SIMS, source selection is integrated into query access planning, so SIMS will attempt to minimize the overall cost of a query and not just the number of sources accessed. The Model assisted Global Querying System (MGQS) [6] uses a model (a metadatabase in their terminology) to describe the contents, organization, and data management facilities of the data sources it accesses. There are, however, significant differences between MGQS and SIMS in the modeling methodology and the reformulation processes. The primary ....

Waiman Cheung. The Model-assisted Global Query System. PhD thesis, Computer Science Department, Rensselaer Polytechnic Institute, Troy, NY, 1991.

....containing: 1) a central knowledge base and (2) distributed rule processors. The central knowledge base, called a metadatabase, contains a description of the different application systems of the enterprise and the knowledge describing how these different application systems are integrated [2] [4], 5] 6] 7] 8] 9] This knowledge includes database integrity rules, enforcing consistency across distributed databases, and business rules, describing how the information is transfered from one application system to the other. For each of the application systems, we define a rule ....

....processor is identical, it might prove inappropriate when the distributed processors are heterogeneous and the rules refer to specific routines located in specific processors. Using the Metadatabase approach, we can also take advantage of the global query facility and its query language ( 1] [4]) to create a temporary fact base, which in turn is used to process the rule. Once a rule is triggered, the rule processor currently executing it is in charge of building that temporary fact base. The fact base serves as a basis for the execution of the rule itself (condition and actions) Once ....

[Article contains additional citation context not shown here]

W. Cheung, The Model-Assisted Global Query System, PhD thesis, Computer Sciences, Rensselaer Polytechnic Institute, Troy, N.Y., November 1991.

....information flows [9] In the Rensselaer Metadatabase system, data, along with knowledge in the form of rules, are unified and used to manage the complex and distributed environment. The union of data and knowledge is believed to be the cutting edge of research in information integration [2, 3, 14]. Application Application Application Common Data Base Common Data Model Single Manufacturer s Hardware Single Logical Database Figure 2a : Prior Approaches to Distributed Databases Prior approaches to integration included use of common databases for several application systems, use of a single ....

.... model includes substantial knowledge about the interaction of data [2, 10] Through the use of this new repository model as a knowledge base, advanced global query capabilities have been provided to end users and programmers without requiring detailed technical knowledge of the local systems [3, 9]. Similarly, using the metadatabase for systems integration, methods have been developed to make heterogeneous application databases work together concurrently and synergistically, without necessitating a central computer to control them directly [8, 9] Information Modeling Repository Model ....

[Article contains additional citation context not shown here]

W. Cheung, "The Model-Assisted Global Query System," unpublished PhD Thesis - Decision Sciences and Engineering Systems, Rensselaer Polytechnic Institute, November 1991.

....Artificial Intelligence (DAI) field and its application to the distributed Knowledge Based Systems (KBS) Section 4 investigates the use of DAI to improve the Metadatabase integration approach. We conclude the paper in Section 5. 2 The Metadatabase Approach Rensselaer s Metadatabase approach [3,4,12,13] was developed to integrate information systems, more specifically manufacturing systems. Manufacturing systems are heterogeneous and distributed by nature. To produce finished goods, many systems must cooperate. These systems might include an Order Processing System, used to record customers ....

W. Cheung. The Model-Assisted Global Query System. PhD thesis, Computer Sciences, Rensselaer Polytechnic Institute, Troy, N.Y., November 1991.

....and at the same time local system autonomy has led to the development of a Metadatabase (i.e. a database of metadata) system, that is, a knowledge base containing both logical and physical data characteristics of local systems. The Metadatabase project (Babin and Hsu, 1996; Bouziane, 1991; Cheung, 1991; Cheung and Hsu, 1996; Hsu, 1996; Hsu et al. 1992; 5 Hsu et al. 1991) has focused on creating an integration environment and defining its principal components to produce a Metadatabase supported, Rule Oriented concurrent systems solution for the enterprise information integration and ....

....i.e. a rule defined in the Metadatabase and distributed as local behavior rules in the different shells. The Application Monitor functionality can be specified in general terms, allowing implementations on very different platforms. Furthermore, the use of the Global Query System (GQS) facilities (Cheung, 1991; Cheung and Hsu, 1996) actually removes the need to tailor the 11 Application Monitor to the local database. Current implementations of the Application Monitor focus only on the detection of local database activities. Timer. The Timer manages a list of time events. When a time event is due for ....

[Article contains additional citation context not shown here]

Cheung, W. (1991). The Model-Assisted Global Query System. Ph.D. thesis, Troy, NY, USA: Computer Sciences, Rensselaer Polytechnic Institute.

....field list has the appearance of a simple field. When activated, however, the list appears and the user can either traverse and select from the list items or enter a selection manually. 5: A case study A prototype Model assisted Global Query System (MGQS) based on the direct knowledge approach [4] has been built using WPTSER. This prototype is a software system written in the C language and running on a Digital tm workstation. The implementation is an extended effort from Nogues Global Query System [5] The global query manager is fully integrated with the metadata manager (a prototype ....

Cheung, W. The Model-Assisted Global Query System, Ph.D. Thesis, Decision Sciences and Engineering Systems Department, Rensselaer Polytechnic Institute, Troy, N.Y., 1991.

....to the integration problem that assures flexibility and scalability is the use of the metadata concept. This concept has led to the development of a Metadatabase system, that is, a knowledge base containing both logical and physical data characteristics of local systems. The Metadatabase work [2,4,5,8,9,10] has focused on creating an integration environment and defining its principal components to produce a Metadatabase supported, Rule Oriented concurrent systems solution for the enterprise information integration and management problem. The Metadatabase may be seen as a specialized information ....

....database, or a call to a specific procedure, that would result in the execution of a global behavior rule. The Application Monitor functionality can be specified in general terms, allowing implementations on very different platforms. Furthermore, the use of the Global Query System (GQS) facilities [5] actually removes the need to tailor the Application Monitor to the local database. Current implementations of the Application Monitor focus only on the detection of local database activities. Timer. The Timer manages a list of time events. When a time event is due for processing, the Timer ....

W. Cheung. The Model-Assisted Global Query System. PhD thesis, Computer Sciences, Rensselaer Polytechnic Institute, Troy, N.Y., November 1991.

....at the end of the paper) In the Rensselaer Metadatabase system, data, along with knowledge in the form of rules, are unified and used to manage the complex and distributed environment. The union of data and knowledge is believed to be the cutting edge of research in information integration [2, 3, 14]. A major benefit of this union to (end)users is that the system makes it possible to both query and control the information in the enterprise without knowing the details of the individual subsystems or individual information flows [9] Prior approaches to integration included use of common ....

.... knowledge, thus both query formulation and processing can be performed directly in terms of information models with which they are familiar, without either requiring detailed technical knowledge of the local systems, nor relying on integrated schemata which tend to impose changes on local systems [3, 9]. Similarly, using the metadatabase for managing concurrent systems, methods have been developed to make heterogeneous application databases work together concurrently and synergistically, without necessitating a central computer to control them directly [8, 9] The key to this is the ....

[Article contains additional citation context not shown here]

W. Cheung, "The Model-Assisted Global Query System," unpublished Ph.D. Thesis - Decision Sciences and Engineering Systems, Rensselaer Polytechnic Institute, November 1991.

No context found.

W. Cheung, The Model Assisted Global Query System, unpublished Ph.D thesis, Decision Sciences and Engineering Systems Department, Rensselaer Polytechnic Institute, Troy, NY., 12180.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC