Interactive assessment of simulated service qualities by business stakeholders: principles and research issues

We present the principles of an approach supporting the stakeholder involvement in a software process for service-oriented systems in a form of assessing the perceived quality of the software under development in its usage context. This method relies on interactive simulation of service performance and reliability; simulation models are parameterized by the factors influencing service execution; business stakeholders experience simulated service qualities in simulated usage contexts and assess this experience; the obtained assessments can be later used throughout the system lifecycle as a means of control for the quality of the software under development.Наведено принципи підходу, що підтримує участь зацікавлених осіб у процесі розробки сервіс-орієнтованих програмних систем у вигляді оцінювання сприйманої якості розроблюваної системи в контексті її використання. Цей підхід спирається на інтерактивне імітаційне моделювання продуктивності та надійності сервісів; параметрами імітаційних моделей є фактори, що впливають на виконання сервісів; зацікавлені особи висловлюють своє відношення до значень продуктивності та надійності, отриманих при взаємодії з імітаційними моделями якості сервісів у рамках виконання імітаційних моделей їх контекстів використання, надані оцінки можуть бути використані на різних етапах життєвого циклу програмного забезпечення як засоби контролю його якості

Risk analysis in biometric-based Border Inspection System

The main goal of a Border Inspection System is to prevent the entry of individuals who pose a threat to a country. The entry of just one of these persons could have severe consequences. Nevertheless, performing a lengthy border inspection is not possible, given that 240,737 international passengers enter the country in an average day [5]. For this reason, the primary inspection is performed using biometrics traits and information flow processes that have a low false acceptance rate and have a high throughput.;This thesis uses the analytic modeling tool called LQNS (Layered Queueing Network Solver) to solve open models for biometric-based border inspection system and cost curves to evaluate the risk. The contributions of the thesis include a performance model of a biometric-based border inspection using open workloads and a risk model of a biometric-based border inspection using cost curves. Further, we propose an original methodology for analyzing a combination of performance risk and security risk in the border inspection system

Model-based risk assessment

In this research effort, we focus on model-based risk assessment. Risk assessment is essential in any plan intended to manage software development or maintenance process. Subjective techniques are human intensive and error-prone. Risk assessment should be based on architectural attributes that we can quantitatively measure using architectural level metrics. Software architectures are emerging as an important concept in the study and practice of software engineering nowadays, due to their emphasis on large-scale composition of software product, and to their support for emerging software engineering paradigms, such as product line engineering, component based software engineering, and software evolution.;In this dissertation, we generalize our earlier work on reliability-based risk assessment. We introduce error propagation probability in the assessment methodology to account for the dependency among the system components. Also, we generalize the reliability-based risk assessment to account for inherent functional dependencies.;Furthermore, we develop a generic framework for maintainability-based risk assessment which can accommodate different types of software maintenance. First, we introduce and define maintainability-based risk assessment for software architecture. Within our assessment framework, we investigate the maintainability-based risk for the components of the system, and the effect of performing the maintenance tasks on these components. We propose a methodology for estimating the maintainability-based risk when considering different types of maintenance. As a proof of concept, we apply the proposed methodology on several case studies. Moreover, we automate the estimation of the maintainability-based risk assessment methodology

Definition and verification of a set of reusable reference architectures for hybrid vehicle development

Current concerns regarding climate change and energy security have resulted in an increasing demand for low carbon vehicles, including: more efficient internal combustion engine vehicles, alternative fuel vehicles, electric vehicles and hybrid vehicles. Unlike traditional internal combustion engine vehicles and electric vehicles, hybrid vehicles contain a minimum of two energy storage systems. These are required to deliver power through a complex powertrain which must combine these power flows electrically or mechanically (or both), before torque can be delivered to the wheel. Three distinct types of hybrid vehicles exist, series hybrids, parallel hybrids and compound hybrids. Each type of hybrid presents a unique engineering challenge. Also, within each hybrid type there exists a wide range of configurations of components, in size and type. The emergence of this new family of hybrid vehicles has necessitated a new component to vehicle development, the Vehicle Supervisory Controller (VSC). The VSC must determine and deliver driver torque demand, dividing the delivery of that demand from the multiple energy storage systems as a function of efficiencies and capacities. This control component is not commonly a standalone entity in traditional internal combustion vehicles and therefore presents an opportunity to apply a systems engineering approach to hybrid vehicle systems and VSC control system development. A key non-­‐functional requirement in systems engineering is reusability. A common method for maximising system reusability is a Reference Architecture (RA). This is an abstraction of the minimum set of shared system features (structure, functions, interactions and behaviour) that can be applied to a number of similar but distinct system deployments. It is argued that the employment of RAs in hybrid vehicle development would reduce VSC development time and cost. This Thesis expands this research to determine if one RA is extendable to all hybrid vehicle types and combines the scientific method with the scenario testing method to verify the reusability of RAs by demonstration. A set of hypotheses are posed: Can one RA represent all hybrid types? If not, can a minimum number of RAs be defined which represents all hybrid types? These hypotheses are tested by a set of scenarios. The RA is used as a template for a vehicle deployment (a scenario), which is then tested numerically, thereby verifying that the RA is valid for this type of vehicle. This Thesis determines that two RAs are required to represent the three hybrid vehicle types. One RA is needed for series hybrids, and the second RA covers parallel and compound hybrids. This is done at a level of abstraction which is high enough to avoid system specific features but low enough to incorporate detailed control functionality. One series hybrid is deployed using the series RA into simulation, hardware and onto a vehicle for testing. This verifies that the series RA is valid for this type of vehicle. The parallel RA is used to develop two sub-­‐types of parallel hybrids and one compound hybrid. This research has been conducted with industrial partners who value, and are employing, the findings of this research in their hybrid vehicle development programs

Integrated Software Architecture-Based Reliability Prediction for IT Systems

With the increasing importance of reliability in business and industrial IT systems, new techniques for architecture-based software reliability prediction are becoming an integral part of the development process. This dissertation thesis introduces a novel reliability modelling and prediction technique that considers the software architecture with its component structure, control and data flow, recovery mechanisms, its deployment to distributed hardware resources and the system\u27s usage profile

Integrated Software Architecture-Based Reliability Prediction for IT Systems

With the increasing importance of reliability in business and industrial IT systems, new techniques for architecture-based software reliability prediction are becoming an integral part of the development process. This dissertation thesis introduces a novel reliability modelling and prediction technique that considers the software architecture with its component structure, control and data flow, recovery mechanisms, its deployment to distributed hardware resources and the system´s usage profile