Integrating heterogeneous Web services with WebXcript
Despite recent uprising of the Web services technology for programmed interfaces of business-to-business (B2B) e-commerce services (e-services) over the Internet, most sites (e.g., online purchases) can only support Hypertext Markup Language (HTML) for human interactions through Web browsers. Automating client access to these services generally requires developing sophisticated programs to simulate human access by handling HTML pages and forms. However, these HTML interfaces vary across Web sites, and are often subjected to changes. Client maintenance is therefore tedious and expensive. This paper presents a novel approach to automate dialogs with Web-based services, using a high-level script language, called WebXcript. WebXcript provides features for HTML forms based dialogues and XML messaging. The XML syntax of WebXcript further enables convenient user authoring and easy engine development with extensively available XML tools. It supports expected responses and exception handling. We further propose a wrapper architecture to integrate heterogeneous Web services based on WebXcript. We demonstrate the applicability of our approach with examples in integrating distributed information, online ordering, and XML messaging.

title: Exploiting automatic analysis of e-commerce protocols
abstract: While e-commerce continuously grows prosperous, some advantages e-commerce applications claimed haven't really been gained. More seriously, the availability and reliability of these systems are particularly hard to obtain. The e-commerce protocols, as the core of e-commerce applications, ask for new development approach and techniques to be introduced for their highly reliable and safe design and implementation. This paper describes research on synthesis of extended UML formalism and formal verification techniques for automatic development of e-commerce protocols. In this paper, we refine AUML protocol diagrams for visual modeling, and develop algorithm and rules to translate visually modeled e-commerce protocols into formal models that are then validated using model checking. This approach is applied to the design of an e-commerce protocol, NetBill, as example. Our objective is to create tools that enable designers to automatically develop available and reliable e-commerce protocols.

title: A Multi-Agent Infrastructure for Mobile Workforce Management in a Service Oriented Enterprise
abstract: With recent advances in mobile technologies and infrastructures, there are increasing demands for the support of mobile workforce management (MWM) across multiple platforms. Mobile users can interact with the MWM system through SMS messages or Web browsers from personal computers, PDA devices, or WAP phones. MWM typically involves tight collaboration, negotiation, and sophisticated business domain knowledge. Therefore, the main challenge of MWM for a service oriented enterprise is the integration of disparate business function for its mobile professional workforce and the management with a unified infrastructure, together with the provision of personalized assistance and automation. These requirements can be facilitated with the use of intelligent software agents, but has not been adequately studied before. As mobile devices become more powerful, intelligent software agents can now be deployed on these devices and hence also subject to mobility. Thus, MWM systems have to accommodate these requirements as well as the support of heterogeneous platforms. In this paper, we formulate a scalable, flexible, and intelligent multi-agent information system (MAIS) infrastructure for MWM with agent clusters in the context of a large service oriented enterprise. Each agent cluster comprise several types of agents to achieve the goal of each phase of the workforce management process, namely, task formulation, matchmaking, brokering, commuting, and service. We evaluate our approach against different stakeholders' perspective.

title: Checking safety properties using compositional reachability analysis
abstract: The software architecture of a distributed program can be represented by a hierarchical composition of subsystems, with interacting processes at the leaves of the hierarchy. Compositional reachability analysis (CRA) is a promising state reduction technique which can be automated and used in stages to derive the overall behavior of a distributed program based on its architecture. CRA is particularly suitable for the analysis of programs that are subject to evolutionary change. When a program evolves, only the behaviors of those subsystems affected by the change need be reevaluated. The technique however has a limitation. The properties available for analysis are constrained by the set of actions that remain globally observable. Properties involving actions encapsulated by subsystems may therefore not be analyzed. In this article, we enhance the CRA technique to check safety properties which may contain actions that are not globally observable. To achieve this, the state machine model is augmented with a special trap state labeled as π. We propose a scheme to transform, in stages, a property that involves hidden actions to one that involves only globally observable actions. The enhanced technique also includes a mechanism aiming at reducing the debugging effort. The technique is illustrated using a gas station system example.

title: A three-layer architecture for e-contract enforcement in an e-service environment
abstract: In an e-service environment, contracts are important for attaining business process interoperability and enforcing their proper enactment.  In the document layer, contracts are composed of different types of clauses. In the business layer, e-contract enforcement activities are defined through the realization of contract clauses as business rules in event-condition-action (ECA) form. In the implementation layer, cross-organizational e-contract enforcement interfaces are implemented with contemporary Enterprise Java Bean and Web services. We present a methodology for the engineering of e-contracts enforcement from a high-level document-view down to the implementation layer based on this architecture, using a supply-chain example. As a result, e-contracts can be seamlessly defined and enforced. Conceptual models of various layers are given in the Unified Modeling Language (UML).

title: Developing a Distributed e-Monitoring System for Enterprise Website and Web Services: An Experience Report with Free Libraries and Tools
abstract: Enterprises value monitoring as it provides dependable e-services, whether it is an interactive Web site or programmatic Web service. However, this task becomes non-trivial when enterprises begin to require support from thousands of servers across geographical areas. How can the communications between a monitoring systems and remote servers be minimized? Could the task be achieved easily based on a readily available technology such as SNMP? How can we monitor thousands of servers powered by, say, Tomcat, which lacks SNMP support? How may a poorly responsive site be identified prior to being reported as a failure by SNMP? In this paper, we propose a unified e-monitoring system that enables system administrators to remotely monitor the health of distributed e-services in both the form of Web site and Web services. We further discuss our implementation experience based on a pragmatic prototype.

title: Denial of service against the Domain Name System
abstract: Because many network services rely on the Domain Name System, denial-of-service attacks against it can be particularly damaging. This article analyzes such threats and reviews existing and proposed countermeasures for addressing them.

title: Efficient video similarity measurement with video signature
abstract: The proliferation of video content on the Web makes similarity detection an indispensable tool in Web data management, searching, and navigation. We propose a number of algorithms to efficiently measure video similarity. We define video as a set of frames, which are represented as high dimensional vectors in a feature space. Our goal is to measure ideal video similarity (IVS), defined as the percentage of clusters of similar frames shared between two video sequences. Since IVS is too complex to be deployed in large database applications, we approximate it with Voronoi video similarity (VVS), defined as the volume of the intersection between Voronoi cells of similar clusters. We propose a class of randomized algorithms to estimate VVS by first summarizing each video with a small set of its sampled frames, called the video signature (ViSig), and then calculating the distances between corresponding frames from the two ViSigs. By generating samples with a probability distribution that describes the video statistics, and ranking them based upon their likelihood of making an error in the estimation, we show analytically that ViSig can provide an unbiased estimate of IVS. Experimental results on a large dataset of Web video and a set of MPEG-7 test sequences with artificially generated similar versions are provided to demonstrate the retrieval performance of our proposed techniques.

title: Insensitive bounds for the moments of the sojourn time distribution in the M/G/1 processor-sharing queue
abstract: This paper studies the M/G/1 processor-sharing (PS) queue, in particular the sojourn time distribution conditioned on the initial job size. Although several expressions for the Laplace-Stieltjes transform (LST) are known, these expressions are not suitable for computational purposes. This paper derives readily applicable insensitive bounds for all moments of the conditional sojourn time distribution. The instantaneous sojourn time, i.e., the sojourn time of an infinitesimally small job, leads to insensitive upper bounds requiring only knowledge of the traffic intensity and the initial job size. Interestingly, the upper bounds involve polynomials with so-called Eulerian numbers as coefficients. In addition, stochastic ordering and moment ordering results for the sojourn time distribution are obtained.

title: Video similarity detection with video signature clustering
abstract: The proliferation of video content on the Web makes similarity detection an indispensable tool in Web data management, searching, and navigation. We have previously proposed a compact representation of video clips, called video signature, for retrieving similar video clips in large databases. In this paper, we propose a new signature clustering algorithm to further improve retrieval performance. The algorithm treats all the signatures as an abstract threshold graph, where the threshold is determined based on local data statistics. Similar clusters are identified as highly connected regions in the graph. This algorithm outperforms simple thresholding and hierarchical clustering techniques in identifying a set of manually-determined similar clusters from a dataset of 46,356 Web video clips. At 95% precision, our algorithm attains 85% recall while simple thresholding and complete-link hierarchical scheme attain 67% and 75% recall respectively. Applying our algorithm to the entire dataset, 6,900 similar clusters are identified, with an average cluster size of 2.81 video clips. The distribution of cluster sizes follows a power-law distribution, which has been shown to describe many Web phenomena.

title: Mesh Permutation Routing with Locality
abstract: Given the permutation routing problem on mesh-connected arrays with a known maximum distance, d, between any source- destination pair, we show how sorting and the greedy algorithm can be combined to yield a deterministic, asymptotically optimal algorithm for solving the problem. This simple algorithm runs in d+O(df(d)) time and requires an O(f;(d)) buffer size (or O(d) time and constant buffer size if we choose f(d) to be a constant). It also gives efficient solutions to the k-k routing problem with locality.