Formally-Based Testing of Radiotherapy Accelerators

The paper presents the aims and research plan of the CONFORMED project (Conformance Of Radiological/Medical Devices). This three-year project will develop tools and techniques for modelling and testing radiotherapy equipment. Formal specifications in LOTOS (Language Of Temporal Ordering Specification) will be used to model accelerators formally and to derive tests rigorously based on these specifications

Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

Slicing approach to specification for testability in LOTOS

Ankara : Department of Computer Engineering and Information Science and Institute of Engineering and Science, Bilkent Univ., 1993.Thesis (Master's) -- Bilkent University, 1993.Includes bibliographical references leaves 119-123With the recent increase in the use of formal methods in specification of communication protocols, there is a need to base the conformance testing of protocol implementations on formal specifications. This brings in the problem of finding out special design issues to be used in the specification of such systems that facilitate test generation. This aspect is called Specification For Testability, and it is investigated in this study for the particular formal description technique LOTOS. Specification for testability is approached from the perspective of designing formal base protocol specifications, and then deriving functional specifications from base specifications in order to use in test generation. The method utilized for the derivation of functional specifications is Ccdled slicing. As inspired from previous work in software engineering, slices of protocol specifications are obtained systematically according to the hierarchically designed test suite structures, where each slice corresponds to a particular tunction of the protocol, and subsequent test generation is based on the obtained slices. The techni(|ues developed are demonstrated on the simple state-oriented specifications of INRES and ACSE protocols along with a real base specification of the OSI Transport Protocol written in the constraintoriented specification style. The results indicate that tests derived from functional specifications have some remarkable properties with respect to test case analysis and representation.Ateş, Ahmet FeyziM.S

A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective

A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine

Rigorous Development of Composite Grid Services

CRESS (Communication Representation Employing Systematic Specification) is introduced as notation, a methodology and a toolset for service development. The article focuses on rigorous development of composite grid services, with particular emphasis on the principles behind the methodology. A straightforward graphical notation is used to describe grid services. These are then automatically specified, analysed and implemented. Analysis includes formal verification of desirable service properties, formal validation of test scenarios, testing of implementation functionality, and evaluation of implementation performance. The case study that illustrates the approach is document content analysis to compare two pieces of text. This involves two composite services supported by two partner services. The usability of the service design notation is assessed, and a comparison is made of the approach with similar ones. These show that the CRESS approach to developing services is usable and more complete than other comparable approaches

Easing the Transition from Inspiration to Implementation: A Rapid Prototyping Platform for Wireless Medium Access Control Protocols

Packet broadcast networks are in widespread use in modern wireless communication systems. Medium access control is a key functionality within such technologies. A substantial research effort has been and continues to be invested into the study of existing protocols and the development of new and specialised ones. Academic researchers are restricted in their studies by an absence of suitable wireless MAC protocol development methods. This thesis describes an environment which allows rapid prototyping and evaluation of wireless medium access control protocols. The proposed design flow allows specification of the protocol using the specification and description language (SDL) formal description technique. A tool is presented to convert the SDL protocol description into a C++ model suitable for integration into both simulation and implementation environments. Simulations at various levels of abstraction are shown to be relevant at different stages of protocol design. Environments based on the Cinderella SDL simulator and the ns-2 network simulator have been developed which allow early functional verification, along with detailed and accurate performance analysis of protocols under development. A hardware platform is presented which allows implementation of protocols with flexibility in the hardware/software trade-off. Measurement facilities are integral to the hardware framework, and provide a means for accurate real-world feedback on protocol performance

Comparison of two approaches for test case generations from EFSMs.

Testing is one of the vital steps in software development process. To convey testing, test cases need to be generated to check whether an implementation conforms to the design specification. Design specifications are usually expressed as Extended Finite State Machines (EFSMs) and test cases are actually a path from the initial state to a specific state on that EFSM. One of the most difficult issues of test case generation for EFSMs comes from the fact that infeasible paths exist on EFSMs. Two approaches have been developed in earlier 90s\u27 to generate feasible paths from EFSMs: one is to develop algorithm to search EFSMs directly to generate feasible paths, and the other is to expand EFSMs into Finite State Machines (FSMs), followed by applying FSM techniques to generate feasible paths. Model checking method was proposed recently as a new approach for test case generation. It has some advantages over previous methods such as efficiency on number of states explored. However, by nature, it also has some disadvantages such as time inefficiency. Here we present a comparison between the model checking method and the previous expansion method from pragmatic aspect by running experiments. To carry on this comparison, we implemented a classical expansion algorithm, defined the translation from EFSMs to Promela models, and used SPIN model checker in the model checking approach. We have run sufficient number of test case generation experiments, compared the two approaches on their time consumptions, numbers of states explored, performance changes when EFSMs\u27 sizes increase etc. By this comparison, we can see the tradeoff between time consumptions and the number of states explored in the two approaches and observe their performance changes while EFSMs change. Finally, we show the existence of the trade-off between state efficiency and time efficiency of the two approaches, the impact of domain size of variable value, the native drawbacks of the expansion algorithm and the performance improvement by tuning Premela models.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .T36. Source: Masters Abstracts International, Volume: 44-03, page: 1415. Thesis (M.Sc.)--University of Windsor (Canada), 2005

Rigorous object-oriented analysis

Object-oriented methods for analysis, design and programming are commonly used by software engineers. Formal description techniques, however, are mainly used in a research environment. We have investigated how rigour can be introduced into the analysis phase of the software development process by combining object-oriented analysis (OOA) methods with formal description techniques. The main topics of this investigation are a formal interpretation of the OOA constructs using LOTOS, a mathematical definition of the basic OOA concepts using a simple denotational semantics and a new method for object- oriented analysis that we call the Rigorous Object-Oriented Analysis method (ROOA). The LOTOS interpretation of the OOA concepts is an intrinsic part of the ROOA method. It was designed in such a way that software engineers with no experience in LOTOS, can still use ROOA. The denotational semantics of the concepts of object-oriented analysis illuminates the formal syntactic transformations within ROOA and guarantees that the basic object- oriented concepts can be understood independently of the specification language we use. The ROOA method starts from a set of informal requirements and an object model and produces a formal object-oriented analysis model that acts as a requirements specification. The resulting formal model integrates the static, dynamic and functional properties of a system in contrast to existing OOA methods which are informal and produce three separate models that are difficult to integrate and keep consistent. ROOA provides a systematic development process, by proposing a set of rules to be followed during the analysis phase. During the application of these rules, auxiliary structures are created to help in tracing the requirements through to the final formal model. As LOTOS produces executable specifications, prototyping can be used to check the conformance of the specification against the original requirements and to detect inconsistencies, omissions and ambiguities early in the development process

Distributed systems : architecture-driven specification using extended LOTOS

The thesis uses the LOTOS language (ISO International Standard ISO 8807) as a basis for the formal specification of distributed systems. Contributions are made to two key research areas: architecture-driven specification and LOTOS language extensions. The notion of architecture-driven specification is to guide the specification process by providing a reference-base of pre-defined domain-specific components. The thesis builds an infra-structure of architectural elements, and provides Extended LOTOS (XL) definitions of these elements. The thesis develops Extended LOTOS (XI.) for the specification of distributed systems. XL- is LOTOS enhanced with features for the formal specification of quantitative timing. probabilistic and priority requirements. For distributed systems, the specification of these ‘performance’ requirements, ran be as important as the specification of the associated functional requirements. To support quantitative timing features, the XL semantics define a global, discrete clock which can be used both to force events to occur at specific times, and to measure Intervals between event occurrences. XL introduces time policy operators ASAP (as soon as possible’ corresponding to “maximal progress semantics") and ALAP (late as possible'). Special internal transitions are introduced in XL semantics for the specification of probability, Conformance relations based on a notion of probabilization, together with a testing framework, are defined to support reasoning about probabilistic XL specifications. Priority within the XL semantics ensures that permitted events with the highest priority weighting of their class are allowed first. Both functional and performance specification play important roles in CIM (Computer Integrated Manufacturing) systems. The thesis uses a CIM system known as the CIM- OSA lntegrating Infrastructure as a case study of architecture-driven specification using XL. The thesis thus constitutes a step in the evolution of distributed system specification methods that have both an architectural basis and a formal basis