18913049
SVG Web Environment for Z Specification Language
This paper presents a web environment for the Z formal specification language using the Scalable Vector Graphics (SVG) technology. The Z Specification Web Editor (ZSWE) is the first prototype of a web based graphical editor for the Z specification language. It not only supports graphical editing and global accessibility for the Z formal specifications, but also provides model comprehension facilities such as schema expansion, specification navigation and model querying. This paper outlines the requirement, design and implementation of the tool and its future improvements.
11323124
Reasoning about semantic Web in Isabelle/HOL
Semantic Web is regarded as the next generation of the World Wide Web. It provides not only the structure of the Web but also meaningful semantics for the information presented. To make semantic Web services understandable for distributed agents, formal definitions of the ontologies and their consistencies are essential. However, the existing tools for reasoning about semantic Web ontologies are still primitive. We believe that mature software engineering tools, such as theorem provers, can contribute to the reasoning phase. In this paper, we present an approach of encoding the semantic Web ontology (DAML+OIL) into the generic theorem prover Isabelle/HOL for automatic reasoning. Furthermore, a translation tool was developed to transform semantic Web ontologies into their extended Isabelle theories. With additional intermediate lemmas, Isabelle can be used to perform both subsumption (class) level and instantiation (instance) level reasoning of the semantic Web ontologies.
15850441
Validating Semistructured Data Using OWL
Semistructured data has become prevalent in both web applications and database systems. This rapid growth in use makes the design of good semistructured data essential. Formal semantics and automated reasoning tools enable us to reveal the inconsistencies in a semistructured data model and its instances. The Object Relationship Attribute model for Semistructured data (ORA-SS) is a graphical notation for designing and representing semistructured data. This paper presents a methodology of encoding the semantics of ORA-SS in the Web Ontology Language (OWL) and automatically validating the semistructured data design using the OWL reasoning tool – RACER. Our methodology provides automated consistency checking of an ORA-SS data model at both the schema and instance levels.
1721253
Object-Z web environment and projections to UML
This paper presents the XML/XSL approach to the development of a web environment for the formal speci cation language Object-Z. The projection techniques and tools from Object-Z (in XML) to UML (in XMI) are developed using XSL Transformations (XSLT). Furthermore, Object-Z (itself) is used to specify and design the essential functionalities of the web environment and the projection tools to UML. In a sense, the paper also demonstrates a formal approach to modeling web applications.
17665537
Synthesis of Distributed Processes from Scenario-Based Specifications
Given a set of sequence diagrams, the problem of synthesis is of deciding whether there exists a satisfying object system and if so, synthesize one automatically. It is crucial in the development of complex systems, since sequence diagrams serve as the manifestation of use cases and if synthesizable they could lead directly to implementation. It is even more interesting (and harder) if the synthesized object system is distributed. In this paper, we propose a systematic way of synthesizing distributed processes from Live Sequence Charts. The basic idea is to first construct a CSP specification from the LSC specification, and then use CSP algebraic laws to group the behaviors of each object effectively. The key point is that the behaviors of each object can be decided locally without constructing the global state machine.
16542374
A Reasoning Method for Timed CSP Based on Constraint Solving
Timed CSP extends CSP by introducing a capability to quantify temporal aspects of sequencing and synchronization. It is a powerful language to model real time reactive systems. However, there is no verification tool support for proving critical properties over systems modelled using Timed CSP. In this work, we construct a reasoning method using Constraint Logic Programming (CLP) as an underlying reasoning mechanism for Timed CSP. We start with encoding the semantics of Timed CSP in CLP, which allows a systematic translation of Timed CSP to CLP. Powerful constraint solver like CLP($\mathcal{R}$) is then used to prove traditional safety properties and beyond, e.g., reachability, deadlock-freeness, timewise refinement relationship, lower or upper bound of a time interval, etc. Counter-examples are generated when properties are not satisfied. Moreover, our method also handles useful extensions to Timed CSP. Finally, we demonstrate the effectiveness of our approach through case study of standard real time systems.
9770385
CWS: a comparative web search system
In this paper, we define and study a novel search problem: Comparative Web Search (CWS). The task of CWS is to seek relevant and comparative information from the Web to help users conduct comparisons among a set of topics. A system called CWS is developed to effectively facilitate Web users' comparison needs. Given a set of queries, which represent the topics that a user wants to compare, the system is characterized by: (1) automatic retrieval and ranking of Web pages by incorporating both their relevance to the queries and the comparative contents they contain; (2) automatic clustering of the comparative contents into semantically meaningful themes; (3) extraction of representative keyphrases to summarize the commonness and differences of the comparative contents in each theme. We developed a novel interface which supports two types of view modes: a pair-view which displays the result in the page level, and a cluster-view which organizes the comparative pages into the themes and displays the extracted phrases to facilitate users' comparison. Experiment results show the CWS system is effective and efficient.
16344729
A practical system of keyphrase extraction for web pages
Keyphrases can be used to facilitate Web users grasping the main topic(s) of a Web page. We present a practical system of automatic keyphrase extraction for Web pages. In this system, a regression model was first trained based on a set of human-labeled documents. Then it was used to extract keyphrases from new pages automatically. This paper makes three contributions. First, the structure information in a Web page was investigated for keyphrase extraction task. Second, the query log data associated with a Web page collected by a search engine server were used to help keyphrase extraction. Third, a method was put forward in this paper in order to evaluate the similarity of phrases.
195711992
Video object cut and paste
In this paper, we present a system for cutting a moving object out from a video clip. The cutout object sequence can be pasted onto another video or a background image. To achieve this, we first apply a new 3D graph cut based segmentation approach on the spatial-temporal video volume. Our algorithm partitions watershed presegmentation regions into foreground and background while preserving temporal coherence. Then, the initial segmentation result is refined locally. Given two frames in the video sequence, we specify two respective windows of interest which are then tracked using a bi-directional feature tracking algorithm. For each frame in between these two given frames, the segmentation in each tracked window is refined using a 2D graph cut that utilizes a local color model. Moreover, we provide brush tools for the user to control the object boundary precisely wherever needed. Based on the accurate binary segmentation result, we apply coherent matting to extract the alpha mattes and foreground colors of the object.
7323545
Mining clickthrough data for collaborative web search
This paper is to investigate the group behavior patterns of search activities based on Web search history data, i.e., clickthrough data, to boost search performance. We propose a Collaborative Web Search (CWS) framework based on the probabilistic modeling of the co-occurrence relationship among the heterogeneous web objects: users, queries, and Web pages. The CWS framework consists of two steps: (1) a cube-clustering approach is put forward to estimate the semantic cluster structures of the Web objects; (2) Web search activities are conducted by leveraging the probabilistic relations among the estimated cluster structures. Experiments on a real-world clickthrough data set validate the effectiveness of our CWS approach.
6824970
Spatio-temporal join selectivity
Given two sets S1, S2 of moving objects, a future timestamp tq, and a distance threshold d, a spatio-temporal join retrieves all pairs of objects that are within distance d at tq. The selectivity of a join equals the number of retrieved pairs divided by the cardinality of the Cartesian product S1 × S2. This paper develops a model for spatio-temporal join selectivity estimation based on rigorous probabilistic analysis, and reveals the factors that affect the selectivity. Initially, we solve the problem for ID (point and rectangle) objects whose location and velocities distribute uniformly, and then extend the results to multi-dimensional spaces. Finally, we deal with non-uniform distributions using a specialized spatio-temporal histogram. Extensive experiments confirm that the proposed formulae are highly accurate (average error below 10%).