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Quality of Service: Concept Analysis. Jolanta Miliauskait ė Vilnius University Institute of Mathematics and Informatics. Content. Introduction What is the Quality? What means the Quality of Service? Conclusions. Introduction. quality-driven composition of semantic web services
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Quality of Service: Concept Analysis Jolanta Miliauskaitė Vilnius University Institute of Mathematics and Informatics
Content • Introduction • What is the Quality? • What means the Quality of Service? • Conclusions Baltic DB&IS 2012
Introduction • quality-driven composition of semantic web services • domain-independent characteristics of quality • highly dynamic environment • ontological model Baltic DB&IS 2012
What is the Quality? • The five different meanings of the term quality: • Transcendental (ormetaphysical) view • Product-Based View • User-Based View • Manufacturing-Based View • Value-Based View Baltic DB&IS 2012
What is the Quality? • Transcendental (ormetaphysical) view • “innate excellence” • absolute and universally recognizable, a mark of uncompromising standards and high achievement • an ideal, towards which we should strive but which can never be achieved in objective reality • cannot be measured by experts and can be perceived through experience alone Baltic DB&IS 2012
What is the Quality? • Product-Based View • quantifiable and measurable characteristics or attributes • it examines the quality from inside perspective and assumes that a product which has good internal properties has also good external properties Baltic DB&IS 2012
What is the Quality? • Product-Based View • ISO-9004 standard • quality is defined as • fitness for use • performance • safety • dependability • quality of design Baltic DB&IS 2012
What is the Quality? • Product-Based View • The disadvantages of this approach • it do not take into account preferences of a particular user • it assumes that the absence or presence of an attribute implies higher quality Baltic DB&IS 2012
What is the Quality? • User-Based View • fitnessforpurpose • market-place quality or consumer preference • Idea - quality is an individual matter, and things that best satisfy user preferences have the highest quality • context-dependent Baltic DB&IS 2012
What is the Quality? • User-Based View • highly subjective • product characteristics as • usability • reliability • performance • efficiency • Product is of high quality if it satisfies a large number of users Baltic DB&IS 2012
What is the Quality? • User-Based View • how to sum up varying individual preferences of particular users • how to know which attributes are for quality and which for user satisfaction Baltic DB&IS 2012
What is the Quality? • User-Based View • difficult to develop • user’s satisfaction may change • large number of non-quality issues • function of the differences between customer’s expectation and performance along the quality dimensions Baltic DB&IS 2012
What is the Quality? • Manufacturing-Based View • conformance to requirements specification in which the requirements are stated mostly in technical terms • idea - any deviation from the specification decreases quality • objective and measurable terms • focuses on making error-free products or services • not on the absence or presence of some attributes Baltic DB&IS 2012
What is the Quality? • Manufacturing-Based View • quality of conformance • errors can be eliminated by • conformance to process standards • concentrates on engineering • manufacturing practices • It is supported by ISO 9001 standard and CMM. Baltic DB&IS 2012
What is the Quality? • Value-Based View • the degree of excellence at an acceptable price • it makes a trade-off between cost and quality • the Value-Based View (in the context of web services) • cost • functionality • time to deliver Baltic DB&IS 2012
What is the Quality? • Summary • The concept of quality has • multiple definitions • wide variety of phenomena • context dependent and time period dependent • unique ontological model Baltic DB&IS 2012
What means the Quality of Service? • services and products share many similarities, they differ also in a number of ways • intangibility • heterogeneity • inseparability • Perishability • Conflicting opinions exist on these issues. Baltic DB&IS 2012
What means the Quality of Service? • SQuaRE model for software • Ability to provide specific users with specific service in defined context of use (user-based view of quality) • propose to consider also internal web service quality (manufacturing-based view of quality) • external web service quality (product-based view of quality) Baltic DB&IS 2012
Conclusions • ambiguous and difficult to define precisely • although observations are very significant and highlight some aspects of the nature of this concept, unfortunately, • they are still not enough to develop the ontological model of QoS • more deep analysis of QoS should be done for this aim Baltic DB&IS 2012
Thank you for your attention Baltic DB&IS 2012