Quality of Service: Concept Analysis

Jolanta MiliauskaitėVilnius University

Institute of Mathematics and Informatics

Content

• Introduction • What is the Quality?• What means the Quality of Service?• Conclusions

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Introduction

• quality-driven composition of semantic web services

• domain-independent characteristics of quality

• highly dynamic environment• ontological model

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What is the Quality?

• The five different meanings of the term quality:

Transcendental (or metaphysical) view Product-Based View User-Based View Manufacturing-Based View Value-Based View

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What is the Quality?

Transcendental (or metaphysical) 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

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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

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What is the Quality?

Product-Based View

• ISO-9004 standard quality is defined as • fitness for use• performance• safety • dependability

quality of design

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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

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What is the Quality?

User-Based View• fitness for purpose

• 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

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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

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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

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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

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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

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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.2012-07-09 Baltic DB&IS 2012 14

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

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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

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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.

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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)

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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

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Thank you for your attention

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