Korat-API : an API for building constraint solving problems for Korat

This thesis introduces the foundation of an API for building constraint solving problems for the Korat solver for imperative predicates. Our goal is two-fold: (1) to facilitate the use of Korat as a backend solver for applications that desire using it as a constraint solving engine; and (2) to facilitate optimized analyses using Korat, which follow the spirit of modern constraint solving and software testing techniques. We describe the API and how it uses the core Korat engine, and demonstrate the benefits in two application contexts: (1) using Korat as a backend engine for model counting; and (2) using Korat as test generator. We believe our work introduces a promising approach for making the ability of Korat to efficiently solve imperative predicates more widely applicable, possibly even in new application contexts where Korat has net been used before.Electrical and Computer Engineerin

Logical Concurrency Control from Sequential Proofs

We are interested in identifying and enforcing the isolation requirements of a concurrent program, i.e., concurrency control that ensures that the program meets its specification. The thesis of this paper is that this can be done systematically starting from a sequential proof, i.e., a proof of correctness of the program in the absence of concurrent interleavings. We illustrate our thesis by presenting a solution to the problem of making a sequential library thread-safe for concurrent clients. We consider a sequential library annotated with assertions along with a proof that these assertions hold in a sequential execution. We show how we can use the proof to derive concurrency control that ensures that any execution of the library methods, when invoked by concurrent clients, satisfies the same assertions. We also present an extension to guarantee that the library methods are linearizable or atomic

From Formal Requirement Analysis to Testing and Monitoring of Cyber-Physical Systems

abstract: Cyber-Physical Systems (CPS) are being used in many safety-critical applications. Due to the important role in virtually every aspect of human life, it is crucial to make sure that a CPS works properly before its deployment. However, formal verification of CPS is a computationally hard problem. Therefore, lightweight verification methods such as testing and monitoring of the CPS are considered in the industry. The formal representation of the CPS requirements is a challenging task. In addition, checking the system outputs with respect to requirements is a computationally complex problem. In this dissertation, these problems for the verification of CPS are addressed. The first method provides a formal requirement analysis framework which can find logical issues in the requirements and help engineers to correct the requirements. Also, a method is provided to detect tests which vacuously satisfy the requirement because of the requirement structure. This method is used to improve the test generation framework for CPS. Finally, two runtime verification algorithms are developed for off-line/on-line monitoring with respect to real-time requirements. These monitoring algorithms are computationally efficient, and they can be used in practical applications for monitoring CPS with low runtime overhead.Dissertation/ThesisDoctoral Dissertation Computer Science 201

An Object Oriented Paradigm for Requirements Specifications.

Software engineering defines a formalized five-step life-cycle for software development. These steps are: requirements specification, design, implementation, testing and maintenance. The requirements specification phase of the software development life-cycle is responsible for determining the functionality of the proposed system. In this work, a methodology is developed that enhances the generation of accurate requirements specifications, utilizing an object-oriented paradigm. This research realizes four objectives. First, the process of information transferral between the user and the specification team is enhanced. Second, a working base of knowledge containing the domain-specific information within the initial requirements document is established for use by the specification team. Third, techniques for evaluating the overall quality of the initial requirements document are addressed. Specifically, the problems associated with document ambiguity, completeness, consistency and structure are examined. Finally, a specification paradigm is defined utilizing this knowledge-based specification environment. The paradigm permits the automatic generation of an object-oriented specification model. This model may then be used as an input for the design phase. This paradigm defines a methodology for the establishment and evaluation of the knowledge-based specification environment. The environment permits the incorporation of an object-oriented development strategy into the specification process. In addition, the concept of information traceability throughout the specification process is enhanced

SICStus MT - A Multithreaded Execution Environment for SICStus Prolog

The development of intelligent software agents and other complex applications which continuously interact with their environments has been one of the reasons why explicit concurrency has become a necessity in a modern Prolog system today. Such applications need to perform several tasks which may be very different with respect to how they are implemented in Prolog. Performing these tasks simultaneously is very tedious without language support. This paper describes the design, implementation and evaluation of a prototype multithreaded execution environment for SICStus Prolog. The threads are dynamically managed using a small and compact set of Prolog primitives implemented in a portable way, requiring almost no support from the underlying operating system