Abstract Invariant relations are used to analyze while loops; while their primary application is to derive the function of a loop, they can also be used to derive loop invariants, weakest preconditions, strongest postconditions, sufficient conditions of correctness, necessary conditions of correctness, and termination conditions of loops. In this paper we present two generic invariant relations that capture the semantics of loops whose loop body applies affine transformations on numeric variables.

The Annual Technical Report this year is focused on infrastructure reliability. Infrastructure constitutes those things that are apparent only in their absence. We take the infrastructure for granted, assuming it will always be there. We turn on our water facet, and drinkable water has always flowed out, for most of us, most of the time. Our infrastructure is subject to environment breakages (e.g., earthquakes), accidents (e.g., dig ups of cables), sabotage, intrusion, and compromise. Also everyday component, software or system failures can bring our infrastructure down. Our global connectivity and communications, as well as our world wide distributed development and maintenance systems, increase our productivity and efficiency, but can also increase our vulnerabilities. Our critical infrastructures can be found in many places.

Quality of service (QoS) management in compositions of services requires careful consideration of QoS characteristics of the services and effective QoS management in their execution. A Web service is a software system that supports interoperable application-to-application interaction over the Internet. Web services are based on a set of XML standards such as simple object access protocol (SOAP). The interactions of SOAP messages between Web services form the theoretical model of SOAP message exchange patterns (MEP). Web Services Business Process Execution Language (WSBPEL) defines an interoperable integration model that facilitates automated process integration in intra- and inter-corporate environments. A service-level agreement (SLA) is a formal contract between a Web services requestor and provider guaranteeing quantifiable issues at defined levels only through mutual concessions. Based on a prior research work on message detail record (MDR), this paper further proposes a SOAP message tracking model for supporting QoS end-to-end management in the context of WSBPEL and SLA. This paper motivates the study of QoS management in a Web service composition framework with the evolution of a distributed toolkit in an industrial setting.

Survivability is the ability of a system to maintain a set of essential services despite the presence of abnormal events, such as faults and intrusions. Ensuring system survivability has increased in importance as critical infrastructures have become heavily dependent on computers. In this paper, we present a systematic method for performing survivability analysis of networks. A system architect injects fault and intrusion events into a given specification of a network and then visualizes the effects of the injected events in the form of scenario graphs. In our method, we automatically generate scenario graphs using model checking. Out method enables further global analysis, such as reliability analysis, where mathematical techniques used in different domains are combined in a systematic manner. We illustrate our ideas on an abstract model of the United States Payment System.

A formal procedure is given based on the use of regular expressions, to identify and eliminate nontraversable paths in a structured program. By reducing the use of control variables, the program is transformed into an unstructured variant and then restructured into a semantic equivalent of the original program with nontraversable paths eliminated. The authors demonstrate this procedure with an example and discuss its maintenance advantages.>

No abstract available.

The IBM COBOL Structuring Facility program product was developed using cleanroom software engineering technology in a pipeline of increments with very high quality and productivity. In the cleanroom approach, programs are developed under statistical quality control and mathematical verification is used in place of unit debugging. The formal methods of specification, design, functional verification, and testing are described, together with development and management practices required for maintaining intellectual control over the process.>

Software maintenance can be transformed from the unmanageable, trial-and-error activity into a systematic engineering discipline through application of mathematics-based principles and practices that have wrought a similar transformation in software engineering. The mathematics provides rigorous techniques for converting unstructured programs into structured form, recovering program design documentation, and modifying and verifying programs. While these principles and practices are technical, the ultimate benefits are managerial, in a new level of predictability and control of maintenance operations to meet business needs.>

Structured programming introduced a new discipline for accessing the instructions of a program. In suitable programming languages, this discipline can be described in terms of program design without gotos. It can be shown, for example, that any functional result achievable in a programming language with gotos can be achieved in that same language without gotos if sequence, selection, and iteration control constructs are present. The gotos permit random access to the instructions while sequence, selection, and iteration provide much more limited and disciplined access. The authors introduce a new discipline for accessing the data of a program. Any functional result achievable in a programming language with arrays and pointers can be achieved in that same language without arrays and pointers if set, stack, and queue data types are present. The arrays and pointers permit random access to the data while sets, stacks, and queues provide much more limited and disciplined access.