Derivation of Test Cases for LAP-B from a LOTOS Specification

this paper, we show how this method has been applied to obtain test cases for LAP-B that are comparable, and in fact occasionally better, than those obtained by [KLPU][Kan]. Since TTCN is a common language for the spec- ification of test trees, the test cases obtained are written in TTCN (we should observe, however, that LOTOS itself appears to be adequate for the specification of test trees [Steen]). This technique appears to be valuable for conformance testing, at least until such time as the more formal approaches being developed by other authors become available (see Section 7). It makes it possible to extract test cases directly from (possibly standardized) formal descriptions, eliminating or reducing the importance of the interpretation of the informally specified standard. The formal specification is more complete and precise than the state tables and, unlike the latter, allows full formal treatment of the data part. For example, we shall show that automatic or semiautomatic generation of frame values appear to be possible by using the information contained in selection predicates

Conflict Detection in Call Control using First-Order Logic Model Checking

Feature interaction detection methods, whether online or offline, depend on previous knowledge of conflicts between the actions executed by the features. This knowledge is usually assumed to be given in the application domain. A method is proposed for identifying potential conflicts in call control actions, based on analysis of their pre/post-conditions. First of all, pre/postconditions for call processing actions are defined. Then, conflicts among the pre/post-conditions are defined. Finally, action conflicts are identified as a result of these conflicts. These cover several possibilities where the actions could be simultaneous or sequential. A first-order logic model-checking tool is used for automated conflict detection. As a case study, the APPEL call control language is used to illustrate the approach, with the Alloy tool serving as the model checker for automated conflict detection. This case study focuses on pre/post-conditions describing call control state and media state. The results of the method are evaluated by a domain expert with pragmatic understanding of the system’s behavior. The method, although computationally expensive, is fairly general and can be used to study conflicts in other domains

Inconsistency Detection Method for Access Control Policies

Abstract-In enterprise environments, the task of assigning access control rights to subjects for resources is not trivial. Because of their complexity, distribution and size, access control policies can contain anomalies such as inconsistencies, which can result in security vulnerabilities. A set of access control policies is inconsistent when, for specific situations different incompatible policies can apply. Many researchers have tried to address the problem of inconsistency using methods based on formal logic. However, this approach is difficult to implement and inefficient for large policy sets. Therefore, in this paper, we propose a simple, efficient and practical solution for detecting inconsistencies in access control policies with the help of a modified C4.5 data classification algorithm

Immaturity and Potential of Formal Methods: A personal view

After some remarks on the use of different formal methods in the area of feature interaction detection, the question of the use of these methods in telecommunications systems development is addressed. Nowadays there does not seem to be (yet) a compelling or general need for formal methods. Also these methods are hindered by their fragmentation and discontinuity. Still, it is concluded that the success of formal methods is inevitable in the long run, although the time frame for this success and which methods will prevail remain open questions

Introduction to ODP Computational Model

This paper presents a tutorial introduction to the major features of the RM-ODP computational model [1-4]. The elements of the computational model are introduced and briefly explained. The model is described as an object-oriented framework of distributed applications. Major aspects of the computational model as an interaction model, a construction model, and as a distributed programming model are presented. 1. What is a computational mode