Using Simulation to Aid Decision Making in Managing the Usability Evaluation Process

Context: This paper is developed in the context of Usability Engineering. More specifically, it focuses on the use of modelling and simulation to help decision-making in the scope of usability evaluation. Objective: The main goal of this paper is to present UESim: a System Dynamics simulation model to help decision-making in the make-up of the usability evaluation team during the process of usability evaluation. Method: To develop this research we followed four main research phases: a) study identification, b) study development, c) running and observation and finally, d) reflexion. In relation with these phases the paper describes the literature revision, the model building and validation, the model simulation and its results and finally the reflexion on it. Results: We developed and validated a model to simulate the usability evaluation process. Through three different simulations we analysed the effects of different compositions of the evaluation team on the outcome of the evaluation. The simulation results show the utility of the model in the decision making of the usability evaluation process by changing the number and expertise of evaluators employed. Conclusion: One of the main advantages of using such a simulation model is that it allows developers to observe the evolution of the key indicators of the evaluation process over time. UESim represents a customisable tool to help decision-making in the management of the usability evaluation process, since it makes it possible to analyse how the key process indicators are affected by the main management options of the Usability Evaluation Process

Trustworthy autonomic architecture (TAArch): Implementation and empirical investigation

This paper presents a new architecture for trustworthy autonomic systems. This trustworthy autonomic architecture is different from the traditional autonomic computing architecture and includes mechanisms and instrumentation to explicitly support run-time self-validation and trustworthiness. The state of practice does not lend itself robustly enough to support trustworthiness and system dependability. For example, despite validating system's decisions within a logical boundary set for the system, there’s the possibility of overall erratic behaviour or inconsistency in the system emerging for example, at a different logical level or on a different time scale. So a more thorough and holistic approach, with a higher level of check, is required to convincingly address the dependability and trustworthy concerns. Validation alone does not always guarantee trustworthiness as each individual decision could be correct (validated) but overall system may not be consistent and thus not dependable. A robust approach requires that validation and trustworthiness are designed in and integral at the architectural level, and not treated as add-ons as they cannot be reliably retro-fitted to systems. This paper analyses the current state of practice in autonomic architecture, presents a different architectural approach for trustworthy autonomic systems, and uses a datacentre scenario as the basis for empirical analysis of behaviour and performance. Results show that the proposed trustworthy autonomic architecture has significant performance improvement over existing architectures and can be relied upon to operate (or manage) almost all level of datacentre scale and complexity

Automated Realistic Test Input Generation and Cost Reduction in Service-centric System Testing

Service-centric System Testing (ScST) is more challenging than testing traditional software due to the complexity of service technologies and the limitations that are imposed by the SOA environment. One of the most important problems in ScST is the problem of realistic test data generation. Realistic test data is often generated manually or using an existing source, thus it is hard to automate and laborious to generate. One of the limitations that makes ScST challenging is the cost associated with invoking services during testing process. This thesis aims to provide solutions to the aforementioned problems, automated realistic input generation and cost reduction in ScST. To address automation in realistic test data generation, the concept of Service-centric Test Data Generation (ScTDG) is presented, in which existing services used as realistic data sources. ScTDG minimises the need for tester input and dependence on existing data sources by automatically generating service compositions that can generate the required test data. In experimental analysis, our approach achieved between 93% and 100% success rates in generating realistic data while state-of-the-art automated test data generation achieved only between 2% and 34%. The thesis addresses cost concerns at test data generation level by enabling data source selection in ScTDG. Source selection in ScTDG has many dimensions such as cost, reliability and availability. This thesis formulates this problem as an optimisation problem and presents a multi-objective characterisation of service selection in ScTDG, aiming to reduce the cost of test data generation. A cost-aware pareto optimal test suite minimisation approach addressing testing cost concerns during test execution is also presented. The approach adapts traditional multi-objective minimisation approaches to ScST domain by formulating ScST concerns, such as invocation cost and test case reliability. In experimental analysis, the approach achieved reductions between 69% and 98.6% in monetary cost of service invocations during testin

1 A Survey on Service Quality Description

Quality of service (QoS) can be a critical element for achieving the business goals of a service provider, for the acceptance of a service by the user, or for guaranteeing service characteristics in a composition of services, where a service is defined as either a software or a software-support (i.e., infrastructural) service which is available on any type of network or electronic channel. The goal of this article is to compare the approaches to QoS description in the literature, where several models and metamodels are included. consider a large spectrum of models and metamodels to describe service quality, ranging from ontological approaches to define quality measures, metrics, and dimensions, to metamodels enabling the specification of quality-based service requirements and capabilities as well as of SLAs (Service-Level Agreements) and SLA templates for service provisioning. Our survey is performed by inspecting the characteristics of the available approaches to reveal which are the consolidated ones and which are the ones specific to given aspects and to analyze where the need for further research and investigation lies. The approaches here illustrated have been selected based on a systematic review of conference proceedings and journals spanning various research areas in compute

Towards a Service-Oriented Enterprise: The Design of a Cloud Business Integration Platform in a Medium-Sized Manufacturing Enterprise

This case study research followed the two-year transition of a medium-sized manufacturing firm towards a service-oriented enterprise. A service-oriented enterprise is an emerging architecture of the firm that leverages the paradigm of services computing to integrate the capabilities of the firm with the complementary competencies of business partners to offer customers with value-added products and services. Design science research in information systems was employed to pursue the primary design of a cloud business integration platform to enable the secondary design of multi-enterprise business processes to enable the dynamic and effective integration of business partner capabilities with those of the enterprise. The results from the study received industry acclaim for the designed solutions innovativeness and business results in the case study environment. The research makes contributions to the IT practitioner and scholarly knowledge base by providing insight into key constructs associated with service-oriented design and deployment of a cloud enterprise architecture and cloud intermediation model to achieve business results. The study demonstrated how an outside-in service-oriented architecture adoption pattern and cloud computing model enabled a medium-sized manufacturing enterprise to focus on a comprehensive approach to business partner integration and collaboration. The cloud integration platform has enabled a range of secondary designs that leveraged business services to orchestrate inter-enterprise business processes for choreography into service systems and networks for the purposes of value creation. The study results demonstrated enhanced levels of business process agility enabled by the cloud platform leading to secondary designs of transactional, differentiated, innovative, and improvisational business processes. The study provides a foundation for future scholarly research on the role of cloud integration platforms in enterprise computing and the increased importance of service-oriented secondary designs to exploit cloud platforms for sustained business performance

An evaluation methodology and framework for semantic web services technology

Software engineering has been driven over decades by the trend towards component based development and loose coupling. Service oriented architectures and Web Services in particular are the latest product of this long-reaching development. Semantic Web Services (SWS) apply the paradigms of the Semantic Web to Web Services to allow more flexible and dynamic service usages. Numerous frameworks to realize SWS have been put forward in recent years but their relative advantages and general maturity are not easy to assess. This dissertation presents a solution to this issue. It defines a general methodology and framework for SWS technology evaluation as well as concrete benchmarks to assess the functional scope and performance of various approaches. The presented benchmarks have been executed within international evaluation campaign. The thesis thus comprehensively covers theoretical, methodological as well as practical results regarding the evaluation and assessment of SWS technologies

Session-based concurrency: between operational and declarative views

Communication-based software is ubiquitous nowadays. From e-banking to e-shopping, online activities often involve message exchanges between software components. These interactions are often governed by protocols that explicitly describe the sequences of communication actions that should be executed by each component. Crucially, these protocols are not isolated from a program’s context: external conditions such as timing constraints or exceptional events that occur during execution can affect message exchanges. As an additional difficulty, individual components are typically developed in different programming languages. In this setting, certifying that a program conforms to its intended protocols is challenging. A widely studied program verification technique uses behavioral type systems, which exploit abstract representations of these protocols to check that the program executes communication actions as intended. Unfortunately, the abstractions offered by behavioral type systems may neglect the influence that external conditions have on the program. This thesis addresses this issue by considering programming languages with declarative features, in which the governing conditions of the program can be adequately described. Our work develops correct translations between programming languages to show that languages with declarative features can indeed articulate a unified view of communication-based programs. Specifically, these translations demonstrate that the operational features of communication-based programs can be correctly represented by languages with declarative features. An additional contribution is a hybrid language that combines the best of both worlds, enabling the analysis of operational and declarative features in communication-based programs