17642380
Evolutionary Modeling of Ordinary Differential Equations for Dynamic Systems
This paper presents a new idea of modeling one-dimensional dynamic systems by higher-order ordinary differential equation (HODE) models in stead of by the ARMA models used in the traditional time series analysis. Accordingly, based on the idea of hybrid evolutionary modeling, we modify the HEMA algorithm in (Cao et al., 1998a; Cao et al., 1998b) to approach the modeling problem of HODEs for dynamic systems. Two applications of time series are used to demonstrate its effectiveness and advantages.
28687449
WebGUIDE: Querying and Navigating Changes in Web Repositories
Abstract WebGUIDE is a system for exploring changes to World Wide Web pages and Web structure that supports recursive document comparison: users may explore the differences between pages with respect to two dates. Differences between pages are computed automatically and summarized in a new HTML page, and differences in link structure are shown via graphical representations. WebGUIDE is the combination of two tools that complement one another: the ATT Ciao [6] is a graphical navigator that allows users to query and browse structural connections embedded in a document repository. The union of these tools let users get information on the evolution of pages of interest (both textually and graphically), browse the differences interactively, and dynamically modify the set of pages with which they interact.
5122752
Ciao: a graphical navigator for software and document repositories
Programmers frequently have to retrieve and link information from various software documents to accomplish a maintenance task. Ciao is a graph-based navigator that helps programmers query and browse structural connections embedded in different software and document repositories. A repository consists of a collection of source documents with an associated database that describes their structure. Ciao supports repositories organized in an architecture style called Aero, which exploits the duality between a class of entity-relationship (ER) databases and directed attributed graphs (DAG). Database queries and graph analysis operators in Aero are plug-compatible because they all take an ER database and produce yet another ER database by default. Various presentation filters generate graph views, source views, and relational views from any compatible ER database. The architecture promotes the construction of successively more complex operators using a notion of virtual database pipelines. Ciao has been instantiated for C and C++ program databases, and program difference databases. The latter allows programmers to explore program structure changes by browsing and expanding graphs that highlight changed, deleted, and added entities and relationships. The unifying ER model under ciao also allows users to navigate different software repositories and make necessary connections. We have linked program difference databases and modification request (MR) databases so that users can investigate the connections between MRs and affected entities. Ciao has been applied to several large communications software projects and we report experiences and lessons learned from these applications.
1089156
Visualizing and Analyzing Software Infrastructures
Companies frequently need to redesign their software infrastructures in response to marketplace changes, but they must do so carefully so that the new architecture will not disrupt existing operations or increase operating costs unnecessarily. To support these goals, system architects have long recognized the need to build a repository of information about all of their company's systems and their interfaces. Using this information, architects create system interface diagrams to help them study the existing architecture. The authors discuss their system, Enterprise Navigator, which lets users make ad hoc queries about an enterprise software architecture and then automatically generate the corresponding system interface diagram in real time on the Web.
8351589
Using automatic clustering to produce high-level system organizations of source code
We describe a collection of algorithms that we developed and implemented to facilitate the automatic recovery of the modular structure of a software system from its source code. We treat automatic modularization as an optimization problem. Our algorithms make use of traditional hill-climbing and genetic algorithms.
1773435
Chava: reverse engineering and tracking of Java applets
Java applets have been used increasingly on Web sites to perform client-side processing and provide dynamic content. While many Web site analysis tools are available, their focus has been on static HTML content and most ignore applet code completely. The paper presents Chava, a system that analyzes and tracks changes in Java applets. The tool extracts information from applet code about classes, methods, fields and their relationships into a relational database. Supplementary checksum information in the database is used to detect changes in two versions of a Java applet. Given our Java data model, a suite of programs that query, visualize, and analyze the structural information were generated automatically from CIAO, a retargetable reverse engineering system. Chava is able to process either Java source files or compiled class files, making it possible to analyze remote applets, whose source code is unavailable. The information can be combined with HTML analysis tools to track both the static and dynamic content of many Web sites. The paper presents our data model for Java and describes the implementation of Chava. Advanced reverse engineering tasks such as reachability analysis, clustering, and program differencing can be built on top of Chava to support design recovery and selective regression testing. In particular, we show how Chava is used to compare several Java Development Kit (JDK) versions to help spot changes that might impact Java developers. Performance numbers indicate that the tool scales well.
14356634
A service scheduler in a trustworthy system
The aim of the research is to investigate techniques that support efficient service scheduling algorithms in a service-oriented fault-tolerant real-time distributed system. Techniques we developed include deadline-based real-time scheduling, priority-based scheduling, and redundant resource allocation for fault-tolerance. The system model and scheduling algorithms are designed, and a prototype is implemented to facilitate the investigation and experimentation.
14714015
Robust stability check of fractional order linear time invariant systems with interval uncertainties
For uncertain fractional-order linear time invariant (FO-LTI) systems with interval coefficients described in state space form, the robust stability check problem is solved for the first time in this paper. Both the checking procedure and the Matlab code are presented with two illustrative examples. The conservatism is shown to be small.
887532
A Suite of Schemes for User-Level Network Diagnosis without Infrastructure
It is highly desirable and important for end users, with no special privileges, identify and pinpoint faults inside the network that degrade the performance of their applications. However, existing tools are inaccurate to infer the link-level loss rates and have large diagnosis granularity (in terms of the number of hops). To address these problems, we propose a suite of user-level diagnosis approaches in two categories: (1) only need to be deployed at the source and (2) deployed at both source and destination. For the former, we propose two fragmentation aided diagnosis approaches (FAD), Algebraic FAD and Opportunistic FAD, which uses IP fragmentation to enable accurate link-level loss rate inference. For the latter category, we propose Striped Probe Analysis (SPA) which significantly improves the diagnosis granularity over those of the source-only approaches. Internet experiments are applied to evaluate each individual schemes (including an improved version of the state-of-the-art tool, Tulip [1]) and various hybrid approaches. The results indicate that our approaches dramatically outperform existing work (especially for diagnosis granularity) and provide not only the best performance but also smooth tradeoff among deployment requirement, diagnosis accuracy and granularity.
9049589
A service-oriented modeling and simulation framework for rapid development of distributed applications
Abstract The paper presents a service-oriented distributed modeling and simulation framework that supports the development and evaluation of large scale distributed systems such as network-centric and system-of-systems applications. The distinct features of the framework include a modeling and specification language, dynamic model checking for completeness and consistency, automated code generation from the specification, simulation of different architectures with a template-based platform builder, service-oriented multi-agent simulation for easy re-configuration and re-composition, formal policy specification and enforcement for dynamic verification, and dynamic analyses for evaluation and monitoring. The framework and most of the tools reported in this paper have been implemented and applied in several industrial projects. This paper presents the design principles, user interfaces, its runtime infrastructure, and the experiment results on its performance.
2475006
Content-based video indexing for sports applications using integrated multi-modal approach
To sustain an ongoing rapid growth of video information, there is an emerging demand for a sophisticated content-based video indexing system. However, current video indexing solutions are still immature and lack of any standard. This doctoral consists of a research work based on an integrated multi-modal approach for sports video indexing and retrieval. By combining specific features extractable from multiple audio-visual modalities, generic structure and specific events can be detected and classified. During browsing and retrieval, users will benefit from the integration of high-level semantic and some descriptive mid-level features such as whistle and close-up view of player(s).