6242831
Distributing the Derivation and Maintenance of Subset Descriptor Rules
This draft paper describes a solution to the rule maintenance problem for data descriptor rules derived from data that may subsequently change. The method utilises any available computers in the local area network, to derive and maintain rule sets.
15093463
Arithmetic for Parallel Linear Recursive Query Evaluation in Deductive Databases
An arithmetic approach, such as the Level-Finding method described in this paper for evaluating linear recursive queries in deductive database systems provides great potential for parallel processing. It has advantages over other approaches using state-of-the-art parallel processing technology to improve processing speed. In the arithmetic approach, we identify two kind of parallelism, namely bridge node parallelism and formula parallelism. In this paper, the arithmetic foundations and algorithm to exploit formula parallelism were given. The algorithm is fully parallel.
10379830
Extended Query Answering Using Integrity Rules
The conventional use of databases is commonly restricted to the retrieval of factual data in the form of tuples or records. However most databases also contain metadata in the form of integrity rules which can provide a rich source of additional information not normally available to the user. Integrity rules define what data values and relationships may exist within the database and so their interrogation can provide answers as to whether a certain database state is possible. Our paper describes how this may be achieved and specifies a formal approach to implementing such an enquiry system.
12408680
Utilising Multiple Computers in Database Query Processing and Descriptor Rule Management
A fundamental problem to be solved in systems that derive rules from database tables to use in query optimisation is the workload involved. If the data server has to do the work it can interfere with query processing and cause slower query answering, which is the opposite of the required effect. This paper reports our investigation of the use of multiple workstations in the same local network as the data server to derive and maintain sets of rules describing data subsets. These rules are used in query optimisation. In a local area network of workstations, one computer accepts SQL queries and data manipulation commands from networked clients. This computer provides an interface to one or more database management systems located on computers in the network. It uses a collection of subset-descriptor rules for query reformulation before forwarding the semantically optimised query. It manages a set of workstations in the network, to derive and maintain the rules. The workstations are ordinary networked computers whose spare computing capacity is utilised by spawning background programs on them.
52849083
Data extraction from Web data sources
An explanation is given of the basic data structures used in a new page analysis technique to create wrappers (data extractors) for the result pages produced by Web sites in response to user qeries via Web page forms. The key structure called a tpGrid is a representation of the web page, which is easier to analyse than the raw HTML code. The analysis looks for repetition patterns of sets of tagSets, which are defined in the paper.
2933100
A Statistical Approach to Rule Selection in Semantic Query Optimisation
Semantic Query Optimisation makes use of the semantic knowledge of a database (rules) to perform query transformation. Rules are normally learned from former queries fired by the user. Over time, however, this can result in the rule set becoming very large thereby degrading the efficiency of the system as a whole. Such a problem is known as the utility problem. This paper seeks to provide a solution to the utility problem through the use of statistical techniques in selecting and maintaining an optimal rule set. Statistical methods have, in fact, been used widely in the field of Knowledge Discovery to identify and measure relationships between attributes. Here we extend the approach to Semantic Query Optimisation using the Chi-square statistical method which is integrated into a prototype query optimiser developed by the authors. We also present a new technique for calculating Chi-square, which is faster and more efficient than the traditional method in this situation.
6721869
A Performance Study of Deployment Factors in Wireless Mesh Networks
We present a measurement-parameterized performance study of deployment factors in wireless mesh networks using three performance metrics: client coverage area, backhaul tier connectivity, and fair mesh capacity. For each metric, we identify and study topology factors and architectural features which strongly influence mesh performance via an extensive set of Monte Carlo simulations capturing realistic physical layer behavior. Our findings include: (i) A random topology is unsuitable for a large-scale mesh deployment due to doubled node density requirements, yet a moderate level of perturbations from ideal grid placement has a minor impact on performance. (ii) Multiple backhaul radios per mesh node is a cost-effective deployment strategy as it leads to mesh deployments costing 50% less than with a single-radio architecture, (iii) Dividing access and backhaul connections onto two separate radios does not use the second radio efficiently as it only improves fair mesh capacity 40% to 80% for most users. This is in contrast to using the second radio to move half the user population to a new network operated on the second radio. This work adds to the understanding of mesh deployment factors and their general impact on performance, providing further insight into practical mesh deployments.
6898048
Supporting manufacturing with simulation: model design, development, and deployment
In this paper, we identify and discuss the features we believe are key to the successful use of simulation as a manufacturing support tool. The discussion begins with three sample projects drawn from the authors' industrial and consulting experiences. Using these projects as motivation, we discuss the ideal project lifecycle model design, development, and deployment. For model design, we emphasize the importance of a clear and consistent specification, articulated in a written document. This specification should identify project customers, goals, and deliverables. We next review a range of model development options, stressing the existence of many non-simulation alternatives. We also discuss methods for model verification and validation. Finally, we consider the difficulties of model deployment, including simulation output analysis, data maintenance, and model integration. We close with several suggestions on how best to present simulation results to a management audience.
5441653
Integrating targeted cycle-time reduction into the capital planning process
This paper describes the development and application of an integrated static capacity and dynamic simulation analysis methodology for purchasing equipment capacity. The goal of the study is to address targeted cycle time objectives in a start up recording head wafer manufacturing facility at Seagate Technology, Minneapolis, MN. The short product cycle time, coupled with the competitive nature of the disc drive industry, has made cycle time reduction one of the most important objectives of production capacity planning. This paper describes an equipment procurement strategy in which static capacity analysis is used to identify an initial equipment set with a low slack capacity variable on each tool group. Simulation analysis is then used to identify the critical tool groups that contribute to cycle time delays. The Seagate Industrial Engineering team used the simulation analysis tool Factory Explorer(R) from Wright, Williams and Kelly to perform the cycle time reduction analysis. This targeted approach is compared to the traditional static capacity planning approach of globally applying reserve capacity buffers of 20% or more to achieve the same cycle time reduction goal. Overall, the targeted approach has proven to be efficient in terms of minimizing capital equipment expenditures and also effective on the factory floor.
2266734
Procedures for Integrating Knowledge in a Speech Understanding System
T h i s paper d e s c r i b e s t h e p r o c e d u r e s f o r i n t e g r a t i n g knowledge f rom d i f f e r e n t s o u r c e s i n t h e SRI speech u n d e r s t a n d i n g s y s t e m . A language d e f i n i t i o n sys tem c o o r d i n a t e s — a t t h e ph rase l e v e l — i n f o r m a t i o n f rom s y n t a x , s e m a n t i c s and d i s c o u r s e i n t h e cou rse o f t h e i n t e r p r e t a t i o n o f a n u t t e r a n c e . The sys tem e x e c u t i v e uses t h e s e c o n t e x t u a l c o n s t r a i n t s i n a s s i g n i n g p r i o r i t i e s t o a l t e r n a t i v e i n t e r p r e t a t i o n s , c o m b i n i n g t o p d o w n , b o t t o m u p , and b i d i r e c t i o n a l s t r a t e g i e s a s r e q u i r e d E x p e r i m e n t a l r e s u l t s t h a t d e m o n s t r a t e t h e e f f e c t i v e n e s s o f c o n t e x t c h e c k i n g a r e d i s c u s s e d .
15957762
Sensor networks and grid middleware for laboratory monitoring
By combining automatic environment sensing and experimental data collection with broker based messaging middleware, a system has been produced far the real-time monitoring of experiments whilst away from the lab. Changes in the laboratory environment are encapsulated as simple messages, which are published using an MQTT compliant broker. Clients subscribe to the MQTT stream, and perform a data transform on the messages; this may be to produce a user display or to change the format of the message for republishing. For example, an MQTT client written for the Java MIDP platform can be run on a smart-phone with a GPRS Internet connection, freeing us from the constraints of the network. We present an overview of the technologies used, and how these are helping chemists make the best use of their time