45899286
Computer Supported Cooperative Work Oriented Architecture
13199279
Rule-mitigated collaboration framework
Computer supported cooperative work (CSCW) research is the discipline that explores how to utilize computing and networking technologies to facilitate cooperation and collaboration among people. A variety of research has been conducted on CSCW architecture. However, how to ensure CSCW system effectiveness and efficiency on supporting collaboration remains a challenge. In this paper we present a rule mitigated framework for CSCW applications. This research contributes to the state of the art by presenting a robust and comprehensive architecture to support distributed collaboration.
5758816
Boolean Query Mapping Across Heterogeneous Information Sources
Searching over heterogeneous information sources is difficult because of the nonuniform query languages. Our approach is to allow a user to compose Boolean queries in one rich front end language. For each user query and target source, we transform the user query into a subsuming query that can be supported by the source but that may return extra documents. The results are then processed by a filter query to yield the correct final result. We introduce the architecture and associated algorithms for generating the supported subsuming queries and filters. We show that generated subsuming queries return a minimal number of documents; we also discuss how minimal cost filters can be obtained. We have implemented prototype versions of these algorithms and demonstrated them on heterogeneous Boolean systems.
1146148
A Bayes Net Toolkit for Student Modeling in Intelligent Tutoring Systems
This paper describes an effort to model a student's changing knowledge state during skill acquisition. Dynamic Bayes Nets (DBNs) provide a powerful way to represent and reason about uncertainty in time series data, and are therefore well-suited to model student knowledge. Many general-purpose Bayes net packages have been implemented and distributed; however, constructing DBNs often involves complicated coding effort. To address this problem, we introduce a tool called BNT-SM. BNT-SM inputs a data set and a compact XML specification of a Bayes net model hypothesized by a researcher to describe causal relationships among student knowledge and observed behavior. BNT-SM generates and executes the code to train and test the model using the Bayes Net Toolbox [1]. Compared to the BNT code it outputs, BNT-SM reduces the number of lines of code required to use a DBN by a factor of 5. In addition to supporting more flexible models, we illustrate how to use BNT-SM to simulate Knowledge Tracing (KT) [2], an established technique for student modeling. The trained DBN does a better job of modeling and predicting student performance than the original KT code (Area Under Curve = 0.610 > 0.568), due to differences in how it estimates parameters.
9888562
Towards building a MetaQuerier: extracting and matching Web query interfaces
We witness the rapid growth and thus the prevalence of databases on the Web. Our recent study in April 2004 estimated 450,000 online databases. On this deep Web, myriad databases provide dynamic query-based data access through their query interfaces, instead of static URL links. It is thus essential to integrate these query interfaces for integrating the deep Web. The overall goal of the MetaQuerier project aims at opening up the deep Web to users, by building a system to help users exploring and integrating deep Web sources. In particular, to start with, we focus on the integration of deep Web sources in the same domain, which is itself an important integration task. To automate this integration scenario, we need to solve two critical problems: extracting query interfaces and matching query interfaces. To solve the interface extraction problem, we introduce a parsing paradigm by hypothesizing the existence of hidden syntax which describes the layout and semantic of Web interfaces. Also, unlike traditional pairwise schema matching, we propose a holistic matching approach, which matches all schemas at the same time with the hypothesis of a hidden schema model. Therefore, our techniques explore, in essence, "data mining for information integration." That is, we mine the observable information to discover the underlying semantics.
2673174
Automatic complex schema matching across Web query interfaces: A correlation mining approach
To enable information integration, schema matching is a critical step for discovering semantic correspondences of attributes across heterogeneous sources. While complex matchings are common, because of their far more complex search space, most existing techniques focus on simple 1:1 matchings. To tackle this challenge, this article takes a conceptually novel approach by viewing schema matching as correlation mining, for our task of matching Web query interfaces to integrate the myriad databases on the Internet. On this “deep Web ” query interfaces generally form complex matchings between attribute groups (e.g., {author} corresponds to {first name, last name} in the Books domain). We observe that the co-occurrences patterns across query interfaces often reveal such complex semantic relationships: grouping attributes (e.g., {first name, last name}) tend to be co-present in query interfaces and thus positively correlated. In contrast, synonym attributes are negatively correlated because they rarely co-occur. This insight enables us to discover complex matchings by a correlation mining approach. In particular, we develop the DCM framework, which consists of data preprocessing, dual mining of positive and negative correlations, and finally matching construction. We evaluate the DCM framework on manually extracted interfaces and the results show good accuracy for discovering complex matchings. Further, to automate the entire matching process, we incorporate automatic techniques for interface extraction. Executing the DCM framework on automatically extracted interfaces, we find that the inevitable errors in automatic interface extraction may significantly affect the matching result. To make the DCM framework robust against such “noisy” schemas, we integrate it with a novel “ensemble” approach, which creates an ensemble of DCM matchers, by randomizing the schema data into many trials and aggregating their ranked results by taking majority voting. As a principled basis, we provide analytic justification of the robustness of the ensemble approach. Empirically, our experiments show that the “ensemblization” indeed significantly boosts the matching accuracy, over automatically extracted and thus noisy schema data. By employing the DCM framework with the ensemble approach, we thus complete an automatic process of matchings Web query interfaces.
5912642
Predicate rewriting for translating Boolean queries in a heterogeneous information system
Searching over heterogeneous information sources is difficult in part because of the nonuniform query languages. Our approach is to allow users to compose Boolean queries in one rich front-end language. For each user query and target source, we transform the user query into a subsuming query that can be supported by the source but that may return extra documents. The results are then processed by a filter query to yield the correct final results. In this article we introduce the architecture and associated mechanism for query translation. In particular, we discuss techniques for rewriting predicates in Boolean queries into native subsuming forms, which is a basis of translating complex queries. In addition, we present experimental results for evaluating the cost of postfiltering. We also discuss the drawbacks of this approach and cases when it may not be effective. We have implemented prototype versions of these mechanisms and demonstrated them on heterogeneous Boolean systems.