Ljerka Beus-Dukic

COTS Software Quality Evaluation

Assessment and evaluation of COTS software products has become a compulsory and crucial part of any COTS-based software system lifecycle. A risk of selecting a product with unknown quality properties is no longer acceptable. This paper presents a framework for quality evaluation process of COTS software products. Our approach, based on the latest international standards for software product quality and evaluation, provides acquirers of COTS software with a method to select software products with identified and measured quality characteristics.

Real-time scheduling in a generic fault-tolerant architecture

Previous ultra-dependable real-time computing architectures have been specialised to meet the requirements of a particular application domain. Over the last two years, a consortium of European companies and academic institutions has been investigating the design and development of a Generic Upgradable Architecture for Real-time Dependable Systems (GUARDS). The architecture aims to be tolerant of permanent and temporary, internal and external, physical faults and should provide confinement or tolerance of software design faults. GUARDS critical applications are intended to be replicated across the channels which provide the primary hardware fault containment regions. In this paper, we present our approach to real-time scheduling of the GUARDS architecture. We use an extended response-time analysis to predict the timing properties of replicated real-time transactions. Consideration is also given to the scheduling of the inter-channel communications network.

Semantic component selection - SemaCS

In component based software development, project success or failure largely depends on correct software component evaluation. All available evaluation methods require time to analyse components. Due to the black box nature of components, preliminary judgments are made based on vendor descriptions. As there is no standard way of describing components, descriptions have to be interpreted using semantics and domain knowledge. This paper presents a semi-automated generic method for component identification and classification based on generic domain taxonomy and user generated semantic input. Every query is semantically tailored to what is being looked for, arriving at better results then it is currently possible using available automated categorisation systems.

Learning How To Discover Requirements

Requirements engineering (RE) is traditionally taught in academia using an RE process which starts from a well-defined problem. Our approach focuses on the early stages of requirements discovery where students have to learn both about the application domain and about what stakeholders feel is the problem. The approach comprises all the basic elements of requirements, and ways to discover them using many small discovery cycles. In this position paper we outline the rationale for our approach and reflect on our initial experiences with teaching undergraduate RE module using this approach.

Multilevel integrity mechanisms

The purpose of the multilevel integrity mechanisms of the GUARDS architecture is to protect critical components from the propagation of errors due to residual design faults in less-critical components. The notions of multiple integrity levels and multiple criticality levels are very tightly linked, but there is an important distinction. Integrity levels are associated with an integrity policy that defines what is allowed in terms of data flow between levels and resource utilisation by the components at different levels [Totel 1998]. Criticality levels are defined in terms of the potential consequences of failures of components at each level.

Teaching Requirements Engineering: EUROWEB experience

In this paper, we describe the results of cooperation between University of Westminster (UK) and Mediterranean University (Montenegro) in the development of a curriculum for teaching Requirements Engineering (RE). RE is traditionally taught in academia using an RE process which starts from a well-defined problem. Our approach focuses on the early stages of requirements discovery, where students have to learn both about the application domain and about what stakeholders think is the problem. We share our experiences gained through teaching RE to several student cohorts in both institutions and discuss some of the advantages and disadvantages of our approach.

COTS components and DB interoperability

The paper addresses the specific issue of interoperability in heterogeneous databases (DBs) and the possible use of COTS components that may alleviate the DB interoperability problem. A component-based software Architectural Style (AS) for interoperable DBs has been used, and an example of its application given, to identify which role the COTS components may play when populating the architecture. We discuss the characteristics of such COTS components and advocate that such COTS components should be developed with a specific component platform in mind, interoperate within a certain context, and adhere to constraints of our AS.

Specifying timing requirements in domain specific languages for modeling

Complex Real-Time Embedded Systems (RTESs) can be developed using model-based engineering. The problem is choosing a modeling language that has capabilities to model the most important characteristic of RTESs: timing. This paper shows an analysis of the most popular modeling languages and their capabilities to model timing constraints in RTESs. It includes UML, SysML, AADL, MARTE and EAST-ADL. A brief comparison between MARTE and EAST-ADL, based on the case study from the automotive industry, is also included.

LEACH-reformed clusters: A novel cluster formation algorithm in LEACH protocol

The energy in wireless sensor networks is a restrictive resource which primarily affects the life of nodes. Many routing protocols use clustering mechanism to optimize the network lifetime. A problem can occur if the allocation of cluster members is not uniformly distributed. In case of LEACH protocol there are great differences in cluster sizes. Consequently, the energy load of such network becomes disproportional which brings to faster dying of cluster heads that have more members. This paper discusses a novel approach to LEACH algorithm that takes into consideration the number of existing members in each cluster. The proposed algorithm significantly prolongs the period before the first node dies, hence providing better reliability of the clustering process. The results of simulations also revealed considerably less variations of cluster sizes, which is crucial for energy load to be spread more equally.

Semantic distance acquisition in SemaCS

Search functionality and technology is a growing area of research. However, simple search approaches are still frequently used. A simple keyword or thesauri-based search is efficient and can be easily scaled. However, keyword-based search cannot be used to infer what may or may not be relevant to the user and thesauri, or any other expert generated model, is expensive to produce and tends to be of limited applicability. Semantic Component Selection (SemaCS) approach is not tied to any specific domain and does not rely on expert input. SemaCS is based on actual data and statistical semantic distances between words. Information on semantic distances is used for searching and for automated generation of domain model taxonomy. This paper presents SemaCSs means of acquiring these semantic distances - mNGD (2) - and its initial evaluation.