Michalis Nik Xenos

E-commerce system quality assessment using a model based on ISO 9126 and Belief Networks

As business transitions into the new economy, e-system successful use has become a strategic goal. Especially in business to consumer (e-commerce) applications, users highly evaluate the quality of their interactive shopping experience. However, quality is difficult to define and measure and most importantly, it is difficult to measure its impact on the end-user. Among the many research questions that arise, some of the most important concern the exact nature of the quality attributes that define an e-commerce system, and how one could model these attributes in order to increase its acceptance. Bearing in mind that e-commerce systems are actually user/data-intensive web-based software systems, this work performed a survey which resulted in a theoretical model that helps to measure such systems’ dynamics through their decomposition into primary quality characteristics. The proposed model is based on Bayesian Networks and ISO 9126. Besides the emphasis on specific software quality attributes, it also provides a quality assessment process aiding developers to design and produce e-commerce systems of high quality. Using a Bayesian Network the model can be used to combine different types of evidences and provide reasoning from effect to cause and vice versa.

Modelling of distance education forum: Formal languages as interpretation methodology of messages in asynchronous text-based discussion

This article presents a study carried out in the area of distance learning electronic forums. Based on the relevant bibliographic review, electronic forums are increasingly becoming part of the learning process. The specific study was stimulated by previous works relevant to the modelling of the behaviour of IT students at Hellenic Open University (HOU) and addresses the issue of distance learning forum modelling using a formal language, aiming to fill the gap that exists in this area, which is demonstrated by the relevant bibliographic review. For this purpose: (a) a relevant note was submitted to HOUs forums, (b) the main concepts of formal languages were specified, (c) a formal language was created which was specified using mathematical terms and represents the messages of HOUs forum, (d) the correctness of such language was verified using specific examples of its function, (e) a language syntactic check algorithm was designed, (f) the parameters impacting on the effectiveness of a distance learning forum were determined, (g) concepts such as time, group size and volume of information were incorporated into the language and (h) efforts were made to identify the factors impacting on the effectiveness of a distance learning forum and the following concepts were incorporated: time, group size and volume of information, in the language.

On the Quality Assessment of Advanced e-Learning Services

Distance learning has been widely researched the past few years, nevertheless the focus has been more on its technological dimension. Designing, developing and supporting a large scale e‐learning application for Higher Education is still a challenging task in many ways. E‐learning is data‐intensive, user‐driven, and has increasing needs for multiculturalism, efficiency, adaptivity and competiveness. Although the complexity of such systems has increased exponentially, the design process still lacks a systematic quality control procedure. In this work we address the increasing need for new methods that maximize usability, and thus end‐user satisfaction. We analyse the technological, managerial and economic factors that affect the design and deployment of a large e‐learning platform with advanced services and propose a set of new metrics for assessing its quality. The metrics are based on the four external quality characteristics (functionality, usability, efficiency and reliability) of the ISO9126 standard for software systems.

Software Quality: The User's Point of View

In this paper is presented a methodological approach for the measurement and the evaluation of users’ opinion for a software product. The methodology is general and applicable for every product and, as a concept, in every situation. The basic principle for the methodology is that each user’s opinion should be evaluated in analogy to this user’s qualifications in respect to computers in general, to this particular product and to the application automated by this. Therefore, the measurement and the analysis of the users’ qualifications is performed before users are asked for their opinion about the product. Afterwards, the users will be asked their opinion about the product. This opinion counts equally to their pre-measured qualifications.

Usability Assessment Heuristics in New Genre Videogames

In this paper, we introduce a new set of heuristics that can be used to carry out usability studies on new genre video games. The definition new genre games refers to videogames that use specific and unique equipment or are part of a general software category such as platforms of social networking. Based on videogame usability problems stated in game reviews on relevant websites and in earlier scientific researches, heuristics were developed to help resolve usability problems in gameplay and game interface level. In addition usability problems concerning new genre videogames were identified through an integrated experimental procedure that took place in HOU’s quality assessment laboratory or in players’ own place by using suitable software developed by the Software Quality Research Group (SQRG) to simulate laboratory functions. Once the heuristics had been developed, they were applied on the observation procedure during the players’ encounters with the games Wii Sports and Pet Society (used inside the famous networking platform Facebook). The validity of heuristics is tested through two different usability evaluating methods; users logging and heuristic evaluation.

Early Estimation of Users' Perception of Software Quality

This paper presents a methodology for estimating users’ opinion of the quality of a software product. Users’ opinion changes with time as they progressively become more acquainted with the software product. In this paper, we study the dynamics of users’ opinion and offer a method for assessing users’ final perception, based on measurements in the early stages of product release. The paper also presents methods for collecting users’ opinion and from the derived data, shows how their initial belief state for the quality of the product is formed. It adapts aspects of Belief Revision theory in order to present a way of estimating users’ opinion, subsequently formed after their opinion revisions. This estimation is achieved by using the initial measurements and without having to conduct surveys frequently. It reports the correlation that users tend to infer among quality characteristics and represents this correlation through a determination of a set of constraints between the scores of each quality characteristic. Finally, this paper presents a fast and automated way of forming users’ new belief state for the quality of a product after examining their opinion revisions.

Weight-modeling of B2C system quality

The efficiency and cost effectiveness of internet technologies have already transformed the web into a global environment for business. However, designing, developing and supporting e-commerce systems having quality in mind is a challenging task. The quality of a Business to Consumer system may be assessed from two complementary, orthogonal, points of view: as a software system and as a service to end-users/customers. As a software system it must be assessed by professional software engineers, the evaluators. They are best in assessing top down the system. As a service it must be assessed by customers perspective, the end-user. They provide a bottom up evaluation approach of the system. In this work, these points of view are combined in a weighted model which uses the external quality characteristics and sub-characteristics of ISO9126 as a baseline for further decomposition into technical and user-oriented features. The model can be used forward and backwards: forward for evaluating in detail the qualitative strengths and weaknesses of an existing B2C system; backwards for balancing quality improvement with development criteria.

Meta-metric Evaluation of E-Commerce-related Metrics

User-perceived software quality is subjective, and thus difficult to be measured. Its importance however in user-centric, web-based systems such as e-commerce systems is huge. How can one measure the subjective? Metrics are one of the most powerful weapons in the arsenal for measuring quality. For such a weapon to be put in good use, guidelines for use should be available. In this paper we present a model based on meta-metrics that suggests what metrics should be used in what way and how, when evaluating an e-commerce system.

Recognizing Emotions in Human Computer Interaction: Studying Stress Using Skin Conductance

This paper reports an experiment for stress recognition in human-computer interaction. Thirty-one healthy participants performed five stressful HCI tasks and their skin conductance signals were monitored. The selected tasks were most frequently listed as stressful by 15 typical computer users who were involved in pre-experiment interviews asking them to identify stressful cases of computer interaction. The collected skin conductance signals were analyzed using seven popular machine learning classifiers. The best stress recognition accuracy was achieved by the cubic support vector machine classifier both per task (on average 90.8 %) and for all tasks (Mean = 98.8 %, SD = 0.6 %). This very high accuracy demonstrates the potentials of using physiological signals for stress recognition in the context of typical HCI tasks. In addition, the results allow us to move on a first integration of the specific stress recognition mechanism in PhysiOBS, a previously-proposed software tool that supports researchers and practitioners in user emotional experience evaluation.

Perceived Usability Evaluation of Learning Management Systems: A First Step towards Standardization of the System Usability Scale in Greek

Perceived usability is an important requirement of educational software, affecting greatly students learning effectiveness and overall learning experience. Although the System Usability Scale (SUS) questionnaire is considered as a de facto standard for perceived usability evaluation, surprisingly, few studies are reporting results from evaluations related to Learning Management Systems (LMSs). In addition, given that the questionnaire comprises 10 questions presented in English, its applicability in studies involving speakers of other languages is questionable. In this paper, a first step towards standardization of a Greek version of SUS in the context of LMSs perceived usability evaluation is reported. To this end, three studies involving 280 university students in both blended and distance learning education were conducted. Analysis of the results demonstrated the validity and reliability of the Greek version of SUS.