Checking subsystem safety properties in compositional reachability analysis
The software architecture of a distributed program can be represented by an hierarchical composition of subsystems, with interacting processes at the leaves of the hierarchy. Compositional reachability analysis has been proposed as a promising automated method to derive the overall behavior of a distributed program in stages, based on its architecture. The method is particularly suitable for the analysis of programs which are subject to evolutionary change. When a program evolves, only behavior of those subsystems affected by the change need be re-evaluated. The method however has a limitation. The properties available for analysis are constrained by the set of actions that remain globally observable. The properties of subsystems, may not be analyzed. We extend the method to check safety properties of subsystems which may contain actions that are not globally observable. These safety properties can still be checked in the framework of compositional reachability analysis. The extension is supported by augmenting finite-state machines with a special undefined state /spl pi/. The state is used to capture possible violation of the safety properties specified by software developers. The concepts are illustrated using a gas station system as a case study.

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: Constraint-based negotiation in a multi-agent information system with multiple platform support
abstract: Agent technologies have been deployed to model and implement e-commerce activities as multi-agent information systems (MAIS). Agents provide services to one another for mutual gain on behalf of their users. This paper presents an MAIS infrastructure based on belief-desire-in tension (BDI) agent architecture, constraint technology, and contemporary Web services to facilitate negotiation support. Further, the MAIS infrastructure also supports customizable degree of agent delegation for users on different platforms, with or without agent support. We present a constraint-based negotiation protocol extended for a MAIS environment and detail the required adaptations on different platforms from a three-tier implementation architecture aspect.

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: 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: An efficient message authentication scheme for link state routing
abstract: We study methods for reducing the cost of secure link state routing. In secure link state routing, routers may need to verify the authenticity of many routing updates, and some routers such as border routers may need to sign many routing updates. Previous work such as public-key based schemes are very expensive computationally or have certain limitations. This paper presents an efficient solution, based on a detection-diagnosis-recovery approach, for the link state routing update authentication problem. Our scheme is scalable to handle large networks, applicable to routing protocols that use multiple-valued cost metrics, and applicable even, when link states change frequently.

title: The chaos router chip: design and implementation of an adaptive router

title: Dependable Intrusion Tolerance: technology demo
abstract: The Dependable Intrusion Tolerance (DIT) architecture is a flexible, adaptive, and intrusion-tolerant server design. We briefly discuss its prototype implementation and validation, and demonstrate how it resists sample attacks.

title: Fast similarity search on video signatures
abstract: Video signatures are compact representations of video sequences designed for efficient similarity measurement. In this paper, we propose a feature extraction technique to support fast similarity search on large databases of video signatures. Our proposed technique transforms the high dimensional video signatures into low dimensional vectors where similarity search can be efficiently performed. We exploit both the upper and lower bounds of the triangle inequalities in approximating the high-dimensional metric, and combine this approximation with the classical PCA to achieve the target dimension. Experimental results on a large set of Web video sequences show that our technique outperforms fastmap, Haar wavelet, PCA, and triangle-inequality pruning.

title: Automatic analysis of firewall and network intrusion detection system configurations
abstract: Given a network that deploys multiple firewalls and network intrusion detection systems (NIDSs), ensuring that these security components are correctly configured is a challenging problem. Although models have been developed to reason independently about the effectiveness of firewalls and NIDSs, there is no common framework to analyze their interaction. This paper presents an integrated, constraint-based approach for modeling and reasoning about these configurations. Our approach considers the dependencies among the two types of components, and can reason automatically about their combined behavior. We have developed a tool for the specification and verification of networks that include multiple firewalls and NIDSs, based on this approach. This tool can also be used to automatically generate NIDS configurations that are optimal relative to a given cost function.