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Missouri University of Science and Technology

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Articles 1501 - 1530 of 1938

Full-Text Articles in Computer Sciences

Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object- oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system …

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Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object-oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system is …

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Anatomy Of The Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Wee Keong Ng, Sanjay Kumar Madria, Ee Peng Lim Jun 2002

Anatomy Of The Coupling Query In A Web Warehouse, Sourav S. Bhowmick, Wee Keong Ng, Sanjay Kumar Madria, Ee Peng Lim

Computer Science Faculty Research & Creative Works

To populate a data warehouse specifically designed for Web data, i.e. web warehouse, it is imperative to harness relevant documents from the Web. In this paper, we describe a query mechanism called coupling query to glean relevant Web data in the context of our web warehousing system called Warehouse of Web Data (WHOWEDA). Coupling query may be used for querying both HTML and XML documents. Some of the important features of our query mechanism are ability to query metadata, content, internal and external (hyperlink) structure of Web documents based on partial knowledge, ability to express constraints on tag attributes and …

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Adaptive Predictive Congestion Control Of High-Speed Atm Networks, Sarangapani Jagannathan, Jayasree Talluri Jun 2002

Adaptive Predictive Congestion Control Of High-Speed Atm Networks, Sarangapani Jagannathan, Jayasree Talluri

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an auto regressive moving average (ARMAX)-based adaptive control methodology to prevent congestion in high-speed asynchronous transfer mode (ATM) networks. Adaptive controller is developed to control traffic where sources adjust their transmission rates in response to the feedback information from the network switches. Specifically, the buffer dynamics at a given switch is modeled as a nonlinear discrete-time system and an ARMAX controller is designed so as to predict the explicit values of the transmission rates of the sources so as to prevent congestion. Tuning methods are provided for the unknown coefficients of the ARMAX model to estimate the …

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Controlling Web Query Execution In A Web Warehouse, Sanjay Kumar Madria, Sourav S. Bhowmick Jan 2002

Controlling Web Query Execution In A Web Warehouse, Sanjay Kumar Madria, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

Most of the contemporary Web query systems have limited capabilities in controlling Web query execution. Such query facility is important as it gives us an opportunity to optimize the evaluation of a Web query. We address this issue in the context of our Web warehousing system called WHOWEDA (Warehouse Of Web Data). Specifically, we investigate different types of constraints (related to query execution) which may be imposed on a Web query such as number of query results, time of execution, restrict the evaluation of a query to specified set of Web sites, etc. An important feature of our approach is …

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Quantitative Analysis Of Transmission Power Control In Wireless Ad-Hoc Networks, Seung Jong Park, R. Sivakumar Jan 2002

Quantitative Analysis Of Transmission Power Control In Wireless Ad-Hoc Networks, Seung Jong Park, R. Sivakumar

Computer Science Faculty Research & Creative Works

In this paper, we address the issue of transmission power control in wireless ad-hoc networks. In general, it is assumed that the minimum transmission power required to keep the network connected achieves the optimal throughput performance in an ad-hoc network. In contrast, we show that using the minimal transmission range might not always result in optimal throughput performance. Using both throughput and throughput per unit energy as the optimization criteria, we demonstrate that the optimal transmission power is generically a function of the number of stations, the network size, and the traffic load. In particular, we observe that the optimal …

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Adaptive Information Filtering: Concepts And Algorithms, Daniel R. Tauritz Jan 2002

Adaptive Information Filtering: Concepts And Algorithms, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

Adaptive information filtering is concerned with filtering information streams in dynamic (changing) environments. The changes may occur both on the transmission side — the nature of the streams can change — and on the reception side — the interests of the user (or group of users) can change. While information filtering and information retrieval have a lot in common, this dissertation’s primary concern is with the differences. The temporal nature of information filtering necessitates more flexible document representation methods than does information retrieval where all the occurring terms are known in advance. Also, information filtering typically maintains user interest profiles …

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Distributed Power Control In Wireless Communication Systems, Sarangapani Jagannathan, A. T. Chronopoulos, S. Ponipireddy Jan 2002

Distributed Power Control In Wireless Communication Systems, Sarangapani Jagannathan, A. T. Chronopoulos, S. Ponipireddy

Electrical and Computer Engineering Faculty Research & Creative Works

Energy efficiency is a measure of performance in wireless networks. Therefore, controlling the transmitter power at a given node increases not only battery operating life, but also overall system capacity by successfully admitting new links. It is essential to find effective means of power control in point-to-point, broadcasting and multicasting scenarios. Wireless networking presents formidable challenges, and we consider the problem of unicast or point-to-point (peer-to-peer) communication in wireless networks in the presence of other nodes. We study the feasibility of admitting new links in an wireless network operating area while maintaining quality of service (QoS), in terms of signal-to-interference …

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Study Of Relative Effectiveness Of Features In Content-Based Image Retrieval, S. R. Subramanya, Jui Che Teng, Yongjian Fu Jan 2002

Study Of Relative Effectiveness Of Features In Content-Based Image Retrieval, S. R. Subramanya, Jui Che Teng, Yongjian Fu

Electrical and Computer Engineering Faculty Research & Creative Works

Content-based retrieval in image databases requires appropriate features of images to be derived and used in the indexing and searching process. Fast and accurate retrieval is crucial from a user point of view. The kinds of features used, their organization in suitable data structures, and the similarity search scheme, directly affect the speed and quality of content-based retrieval. In this paper, we evaluate the relative significance of three different image features - geometry, moments, and Fourier descriptors in the context of content-based retrieval, and present experimental results. The evaluation metrics are retrieval quality and search time. These could be used …

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A Hybrid System Theoretic Approach For Admission Controller Design In Multimedia Networks, Sarangapani Jagannathan Jan 2002

A Hybrid System Theoretic Approach For Admission Controller Design In Multimedia Networks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel real-time discrete-event admission control (AC) scheme for high-speed networks is proposed with the aim of attaining a desired quality of service (QoS) and high network utilization. The AC uses the available capacity from a novel adaptive bandwidth estimation scheme, a congestion indicator derived from a congestion controller, peak bit/cell rate (PBR/PCR) estimate from new sources, along with the desired QoS metrics, and makes decisions whether to 'admit' or 'reject' new sources. The novel aspect of the proposed approach is the application of hybrid system theory to prove the performance of the admission controller, stability and the development of …

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A Distributed Discrete-Time Neural Network Architecture For Pattern Allocation And Control, A.T. Chronopoulos, Jagannathan Sarangapani Jan 2002

A Distributed Discrete-Time Neural Network Architecture For Pattern Allocation And Control, A.T. Chronopoulos, Jagannathan Sarangapani

Computer Science Faculty Research & Creative Works

No abstract provided.

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Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan Jan 2002

Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan

Electrical and Computer Engineering Faculty Research & Creative Works

A multilayer neural network (NN) controller in discrete-time is designed to deliver a desired tracking performance for a class of nonlinear systems with input deadzones. This multilayer NN controller has an adaptive critic NN architecture with two NNs for compensating the deadzone nonlinearity and a third NN for approximating the dynamics of the nonlinear system. A reinforcement learning scheme in discrete-time is proposed for the adaptive critic NN deadzone compensator, where the learning is performed based on a certain performance measure, which is supplied from a critic. The adaptive generating NN rejects the errors induced by the deadzone whereas a …

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Mechanical Response Of Nets Of Graphical Objects, Rakesh Kumar Bajaj Jan 2002

Mechanical Response Of Nets Of Graphical Objects, Rakesh Kumar Bajaj

Masters Theses

"This research produces networks of graphical objects that respond to human manipulation in a fashion that would be deemed physically reasonable. That is, a graphical network is given a mechanics-like behavior in the presence of the human interaction. In this approach, nonlinear models replace commonly used linear models to mimic physical reality better. Software solutions are provided via a class library useful for such interactive visual modeling"--Abstract, page iii.

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End To End Congestion Control In High-Speed Networks, Sarangapani Jagannathan Jan 2002

End To End Congestion Control In High-Speed Networks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an adaptive methodology to prevent congestion in packet switched networks such as the Internet, where the internal network nodes convey very little information to the ingress nodes. Two architectures of preventing the congestion are presented: the first one when the traffic arrival rates, and bottleneck queue levels are known and the other when these are unknown. In the latter, the network traffic is estimated online using an adaptive system by measuring the buffer occupancy. In both architectures, the congestion is controlled by adjusting the transmission rates of non real-time and certain real-time sources in response to the …

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Node Splitting Algorithms In Tree-Structured High-Dimensional Indexes For Similarity Search, Yongjian Fu, Jui Che Teng, S. R. Subramanya Jan 2002

Node Splitting Algorithms In Tree-Structured High-Dimensional Indexes For Similarity Search, Yongjian Fu, Jui Che Teng, S. R. Subramanya

Computer Science Faculty Research & Creative Works

Content-based searches and retrievals in multimedia and image databases use high-dimensional indexing structures for organizing the features of the objects. Most of those index structures are tree-structured whose nodes have a limit on the number of entries describing the subtrees rooted at those nodes. When index trees are built by repeated insertion of entries, nodes need to be split and the tree balanced accordingly. Node-splitting algorithms eventually determine the final structure of the tree which will have a profound effect on the search performance. This paper presents a comparative study of several node splitting algorithms for a typical high-dimensional indexing …

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A Transaction Model To Improve Data Availability In Mobile Computing, Sanjay Kumar Madria, Bharat Bhargava Sep 2001

A Transaction Model To Improve Data Availability In Mobile Computing, Sanjay Kumar Madria, Bharat Bhargava

Computer Science Faculty Research & Creative Works

We incorporate a prewrite operation before a write operation in a mobile transaction to improve data availability. A prewrite operation does not update the state of a data object but only makes visible the future value that the data object will have after the final commit of the transaction. Once a transaction reads all the values and declares all the prewrites, it can pre-commit at mobile host (MH) (computer connected to unreliable mobile communication network). The remaining transaction's execution (writes on database) is shifted to the mobile service station (MSS) (computer connected to the reliable fixed network). Writes on database …

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A Visual Query System For The Specification And Scientific Analysis Of Continual Queries, Jennifer Leopold, A. Ambler, M. Heimovics, T. Palmer Jan 2001

A Visual Query System For The Specification And Scientific Analysis Of Continual Queries, Jennifer Leopold, A. Ambler, M. Heimovics, T. Palmer

Computer Science Faculty Research & Creative Works

The lack of a facility that would allow nonprogrammers to easily formulate temporal ad hoc analyses over a network of heterogeneous, constantly-updated data sources has been a significant impediment to research, particularly in the scientific community. In this paper we describe WebFormulate, an Internet-based system which facilitates the development of analyses using information obtained from databases on the Internet. The main distinction between this system and existing Internet facilities to retrieve information and assimilate it into computations is that WebFormulate provides the necessary facilities to perform continual queries, developing and maintaining dynamic links such that computations and reports automatically maintain …

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Reorganizing Web Sites Based On User Access Patterns, Yongjian Fu, Mario Creado, Chunhua Ju Jan 2001

Reorganizing Web Sites Based On User Access Patterns, Yongjian Fu, Mario Creado, Chunhua Ju

Computer Science Faculty Research & Creative Works

In this paper, an approach for reorganizing Web sites based on user access patterns is proposed. The approach consists of three steps: preprocessing, page classification, and site reorganization. In preprocessing, pages on a Web site are processed to create an internal representation of the site, and page access information of its users is extracted from its server log. In page classification, the Web pages on the site are classified into two categories, index pages and content pages, based on the page access information. After the pages are classified, in site reorganization, the Web site is examined to find better ways …

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Mobile Data Management, Sanjay Kumar Madria, Sourav S. Bhowmick Jan 2001

Mobile Data Management, Sanjay Kumar Madria, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

The management of data in the mobile computing environment offers new challenging problems. Existing software needs to be upgraded to accommodate this environment. To do so, the critical parameters need to be understood and defined. We have surveyed some problems and existing solutions

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Performance Evaluation Of Hybrid Coding Of Images Using Wavelet Transform And Predictive Coding, S. R. Subramanya, Chaman Sabharwal Jan 2001

Performance Evaluation Of Hybrid Coding Of Images Using Wavelet Transform And Predictive Coding, S. R. Subramanya, Chaman Sabharwal

Computer Science Faculty Research & Creative Works

Image compression techniques are necessary for the storage of huge amounts of digital images using reasonable amounts of space, and for their transmission with limited bandwidth. Several techniques such as predictive coding, transform coding, subband coding, wavelet coding, and vector quantization have been used in image coding. While each technique has some advantages, most practical systems use hybrid techniques which incorporate more than one scheme. They combine the advantages of the individual schemes and enhance the coding effectiveness. This paper proposes and evaluates a hybrid coding scheme for images using wavelet transforms and predictive coding. The performance evaluation is done …

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Workstation Clusters For Parallel Computing, J. Stone, Fikret Erçal Jan 2001

Workstation Clusters For Parallel Computing, J. Stone, Fikret Erçal

Computer Science Faculty Research & Creative Works

Workstation clusters have become an increasingly popular alternative to traditional parallel supercomputers for many workloads requiring high performance computing. The use of parallel computing for scientific simulations has increased tremendously in the last ten years, and parallel implementations of scientific simulation codes are now in widespread use. There are two dominant parallel hardware/software architectures in use today: distributed memory, and shared memory. Systems implementing shared memory provide cooperating processes with a shared memory address space that can be accessed by all processors. In shared memory systems, parallel processing occurs through the use of shared data structures, or through emulation of …

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Adaptive Web Sites By Web Usage Mining, Mario Rodney Creado Jan 2001

Adaptive Web Sites By Web Usage Mining, Mario Rodney Creado

Masters Theses

The World Wide Web has become a very popular marketing medium during the recent years. Many businesses use it extensively to publicize their products. Initially it began with static web sites. However as web sites got bigger and better, their maintenance became problematic. Just as business strategies change, so also will the orgainization of their web sites change. Hence the need of the hour is an adaptive web site (i.e. a web site that can organize itself based upon its usage). For this purpose, web usage mining techniques are used. The characteristics of the user's activity on the web site …

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Software Quality Function Deployment, Xiaoqing Frank Liu Dec 2000

Software Quality Function Deployment, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Any product development involves projecting its potential success in achieving its functional and commercial goals. Better quality designs that match customer needs and preferences and integrate other lifecycle issues early in the software development process are more likely to be competitive. Thus, there is significant concern in industry about quality product design, which is addressed by quality function deployment (QFD). QFD uses matrices to organize and relate pieces of data to each other. These matrices are often combined to form a basic tool of QFD, called a House of Quality (HoQ). QFD was developed in the Kobe shipyards as a …

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Web Schemas In Whoweda, Sourav S. Bhowmick, Wee Keong Ng, Sanjay Kumar Madria Nov 2000

Web Schemas In Whoweda, Sourav S. Bhowmick, Wee Keong Ng, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

The term schema denotes whatever way a data model chooses to model its data. In this paper we discuss schemas of a set of HTML or XML documents retrieved from the Web in the context of our web warehousing system called WHOWEDA (Warehouse of Web Data). Web schemas are used to bind a web table that contains a collection of interlinked web documents called web tuples. These schemas specify some of the metadata, content and structural properties (in the form of predicates) shared by some of the Web documents and hyperlinks in the web table. They also summarize the hyperlink …

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Editorial, Sanjay Kumar Madria, Mukesh Mohania, Bharat Bhargava Oct 2000

Editorial, Sanjay Kumar Madria, Mukesh Mohania, Bharat Bhargava

Computer Science Faculty Research & Creative Works

No abstract provided.

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Adaptive Information Filtering: Evolutionary Computation And N-Gram Representation, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper Jan 2000

Adaptive Information Filtering: Evolutionary Computation And N-Gram Representation, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper

Computer Science Faculty Research & Creative Works

Adaptive Information Filtering (AIF) is concerned with filtering information streams in changing environments. The changes may occur both on the transmission side (the nature of the streams can change) and on the reception side (the interests of a user can change). The research described in this paper details the progress made in a prototype AIF system based on weighted n-gram analysis and evolutionary computation. A major advance is the design and implementation of an n-gram class library allowing experimentation with different values of n instead of solely with 3-grams as in the past. The new prototype system was tested on …

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Detecting And Representing Relevant Web Deltas Using Web Join, Sanjay Kumar Madria, Wee Keong, Ee-Peng Lim, Sourav S. Bhowmick Jan 2000

Detecting And Representing Relevant Web Deltas Using Web Join, Sanjay Kumar Madria, Wee Keong, Ee-Peng Lim, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

We show how to detect and represent Web deltas, i.e., changes in Web information, that are relevant to a user's query in the context of our Web warehousing system called WHOWEDA (Warehouse of Web Data). In WHOWEDA, Web information are materialized views stored in Web tables and can be manipulated and analyzed using a set of Web algebraic operators. We present a mechanism to detect relevant Web deltas using Web join and outer Web join. We show how to represent these changes using delta Web tables.

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Reducing Cognitive Overheads In A Web Warehouse Using Reverse-Osmosis, Sanjay Kumar Madria, Wee Keong Ng, Ee-Peng Lim, Sourav S. Bhowmick Jan 2000

Reducing Cognitive Overheads In A Web Warehouse Using Reverse-Osmosis, Sanjay Kumar Madria, Wee Keong Ng, Ee-Peng Lim, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

This paper provides a quantitative analysis of reducing cognitive overheads in a Web warehouse using an important class of operation called reverse osmosis. The analysis is used to examine two different cognitive overheads of locating relevant nodes or information and display time of a Web table. A reverse-osmosis operation enables us to eliminate in relevant information from a collection of Web documents stored in the form of a Web table. We call such an operation reverse-osmosis because it is analogous to the reverse osmosis process in the field of water purification. We discuss a formal algorithm of the reverse-osmosis operation

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A Systolic Image Difference Algorithm For Rle-Compressed Images, Fikret Erçal, Mark Allen, Hao Feng Jan 2000

A Systolic Image Difference Algorithm For Rle-Compressed Images, Fikret Erçal, Mark Allen, Hao Feng

Computer Science Faculty Research & Creative Works

A new systolic algorithm which computes image differences in run-length encoded (RLE) format is described. The binary image difference operation is commonly used in many image processing applications including automated inspection systems, character recognition, fingerprint analysis, and motion detection. The efficiency of these operations can be improved significantly with the availability of a fast systolic system that computes the image difference as described in this paper. It is shown that for images with a high similarity measure, the time complexity of the systolic algorithm is small and, in some cases, constant with respect to the image size. A formal proof …

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Association Rules For Web Data Mining In Whoweda, Sanjay Kumar Madria, C. Raymond, M. Mohania, Sourav S. Bhowmick Jan 2000

Association Rules For Web Data Mining In Whoweda, Sanjay Kumar Madria, C. Raymond, M. Mohania, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

The authors discuss association rules which can be discovered from Web data. The association rules are discussed within the scope of our WHOWEDA (warehouse of Web data) project. WHOWEDA is supported by a Web data model and a set of algebraic operators. The Web data model allows a uniform and integrated view of Web data gathered using a user''s query graph. A user''s query graph describes the query by example (what the user perceives as the query) and the Web coupling query gathers instances of such a query graph from the Web and stores them in the form of subgraphs …

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