ABSTRACT Modern society has a higher demand for quality than it had before. There is a Plethora of quality improvement techniques available which makes it harder for companies to decide which one to apply. They need support in this decision and in knowing how to apply the chosen techniques, if they want to improve their business and stay competitive. Six Sigma approach is a very successful manufacturing quality improvement tool. In the last two decades, it has helped many companies to success. Recently, the Six Sigma approach was introduced in the software development industry. Some software companies have been trying to adapt Six Sigma for their business and development processes. But there are misconceptions about the applicability of Six Sigma in software‟s. Furthermore there is no generic software quality improvement solution based on Six Sigma. So there is a demand to debunk the misconceptions related to the applicability of Six Sigma. And to develop a generic software company quality improvement solution based on Six Sigma approach. In this thesis we take a first step towards such a solution. The thesis starts from Six Sigma concept identification and manufacturing investigation. After conducting interviews, a case study and several case studies reviews, we detail our method. We expect thesis result to be useful for software companies when applying Six Sigma in their company for process improvement. Keywords: Software Quality, Quality Improvement Tool, Six Sigma and Process Improvement

With the rapid advancement of technologies, software is gaining its popularity in assisting our daily activities in the last decades. This circumstance causes a rising concerns about a software product with high quality which lead to a question about the justification whether a software product has high quality. Therefore, a numerous of researches and studies had spent a lot of effort in software product quality assessment in order to justify whether the software product(s) under study have satisfactory quality. One of the foremost approaches to assess software product quality is the application of the quality models. For example, quality model ISO 9126. However, the quality models do not provide an explicit way to aggregate the performance of different quality aspects nor handling the various interests raised from different perspective or stakeholders. Although many studies have been conducted to aggregate the different measures of quality attributes, they are still not capable to include the various interests raised by different software product stakeholders. Therefore, some studies have attempted to apply MCDA methods in order to aggregate the measure of quality attributes as the ultimate software product quality and handling the various quality interests. However, they do not provide any rational about their particular choice of MCDA methods. Most of them justify their choice by referring to high popularity of the selected MCDA method. Without studying the suitability of MCDA methods in the application domain of the software product, it is difficult to conclude whether the chosen MCDA methods fit in the intended software engineering discipline. Furthermore, there is no systematic approach available to help other software practitioners in selecting the MCDA method that will be suitable for their needs and constraints in software product quality assessment. This thesis aims to provide the key concepts for an effective selection of suitable MCDA method for the purpose of software product quality assessment. A foremost part of this thesis presents two systematic reviews. The first review illustrates the evaluation of the characteristics of MCDA methods. The second review identifies the major needs and constraints of the software quality assessment potential MCDA method has to consider in order to be used for assessing quality of software products. Based on the results from both systematic reviews, a selection framework named MCDA-SQA framework is formulated. This framework is intended to assist the software practitioners to systematically select and adapt appropriate MCDA method(s) in order to fulfil their quality assessment needs and the respective environmental concerns.

Context. Software evaluation is a research hotspot of both academia and industry. Users as the ultimate beneficiary of software products, their evaluation becomes more and more importance. In the real word, the users’ evaluation outcomes as the reference for end-users selecting products, and for project managers comparing their product with competitive products. A mobile application is a special software, which is facing the same situation. It is necessary to find and test an evaluation method for a mobile application which based on users’ feedback and give more reference for different stakeholders. Objectives. The aim of this thesis is to apply and evaluate AF in mobile application features rating. There are three kinds of people, and three processes are involved in a rating method applying process, rating designers in rating design process, rating providers in the rating process, and end-users in selecting process. Each process has the corresponding research objectives and research questions to test the applicability of AF method and the satisfaction of using AF and using AF rating outcomes. Methods. The research method of this thesis is a mixed method. The thesis combined experiment, questionnaire, and interview to achieve the research aim. The experiment is using for constructing a rating environment to simulate mobile application evaluation in the real world and test the applicability of AF method. Questionnaire as a supporting method utilizing for collecting the ratings from rating providers. And interviews are used for getting the satisfaction feedback of rating providers and end-users. Results. In this thesis, all AF use conditions are met, and AF evaluation system can be built in mobile application features rating. Comparing with existing method rating outcomes, the rating outcomes of AF are correct and complete. Although, the good feelings of end-users using AF rating outcomes to selecting a product, due to the complex rating process and heavy time cost, the satisfaction of rating providers is negative. Conclusions. AF can be used in mobile application features rating. Although there are many obvious advantages likes more scientific features weight, and more rating outcomes for different stakeholders, there are also shortages to improve such as complex rating process, heavy time cost, and bad information presentation. There is no evidence AF can reply the existing rating method in apps stores. However, there is still research value of AF in future work.

Single-page applications have historically been subject to strong market forces driving fast development and deployment in lieu of quality control and changeable code, which are important factors for maintainability. In this report we develop two functionally equivalent applications using AngularJS and React and compare their maintainability as defined by ISO/IEC 9126. AngularJS and React represent two distinct approaches to web development, with AngularJS being a general framework providing rich base functionality and React a small specialized library for efficient view rendering. The quality comparison was accomplished by calculating Maintainability Index for each application. Version control analysis was used to determine quality indicators during development and subsequent maintenance where new functionality was added in two steps. The results show no major differences in maintainability in the initial applications. As more functionality is added the Maintainability Index decreases faster in the AngularJS application, indicating a steeper increase in complexity compared to the React application. Source code analysis reveals that changes in data flow requires significantly larger modifications of the AngularJS application due to its inherent architecture for data flow. We conclude that frameworks are useful when they facilitate development of known requirements but less so when applications and systems grow in size. Sammanfattning: Ensidesapplikationer har historiskt sett påverkats av starka marknadskrafter som pådriver snabba utvecklingscykler och leveranser. Detta medför att kvalitetskontroll och förändringsbar kod, som är viktiga faktorer för förvaltningsbarhet, blir lidande. I denna rapport utvecklar vi två funktionellt ekvi-valenta ensidesapplikationer med AngularJS och React samt jämför dessa applikationers förvaltningsbarhet enligt ISO/IEC 9126. AngularJS och React representerar två distinkta angreppsätt på webbutveckling, där AngularJS är ett ramverk med mycket färdig funktionalitet och React ett mindre bibliotek specialiserat på vyrendering. Kvalitetsjämförelsen utfördes genom att beräkna förvaltningsbarhetsindex för respektive applikation. Versionshanteringsanalys användes för att bestämma andra kvalitetsindikatorer efter den initiala utvecklingen samt två efterföljande underhållsarbeten. Resultaten visar inga markanta skillnader i förvaltningsbarhet för de initiala applikationerna. I takt med att mer funktionalitet lades till sjönk förvaltnings-barhetsindex snabbare för AngularJS-applikationen, vilket motsvarar en kraftigare ökning i komplexitet jämfört med React-applikationen. Versionshanteringsanalys visar att ändringar i dataflödet kräver större modifikationer för AngularJS-applikationen på grund av dess förbestämda arkitektur. Utifrån detta drar vi slutsatsen att ramverk är användbara när de understödjer utvecklingen mot kända krav men att deras nytta blir begränsad ju mer en applikation växer i storlek.

Pair programming is a programming technique in which two programmers sit literally side by side working on the same task at the same computer. One member of a pair called “driver” is in charge of writing the code. The other member plays a role of “navigator”, working on the more strategic tasks, such as looking for tactical error, thinking about overall structure, and finding better alternatives. Pair programming is claimed to improve product quality, reduce defects, and shorten time to market. On the other hand, it has been criticized on cost efficiency. To increase a body of evidence regarding the real benefits of pair programming, this thesis investigates its effect on software defects and efficiency of defect correction. The analysis bases on 14-month data of project artifacts and developers' activities collected from a large Italian manufacturing company. The team of 16 developers adopts a customized version of extreme programming and practices pair programming on a daily basis. We investigate sources of defects and defect correction activities of approximately 8% of defects discovered during that time, and enhancement activities of approximately 9% of new requirements. Then we analyze whether there exists an effect of pair programming on defect rate, duration and effort of defect correction, and precision of localizing defects. The result shows that pair programming reduces the introduction of new defects when the code needs to be modified for defect corrections and enhancements.

Single-page applications have historically been subject to strong market forces driving fast development and deployment in lieu of quality control and changeable code, which are important factors for maintainability. In this report we develop two functionally equivalent applications using AngularJS and React and compare their maintainability as defined by ISO/IEC 9126. AngularJS and React represent two distinct approaches to web development, with AngularJS being a general framework providing rich base functionality and React a small specialized library for efficient view rendering. The quality comparison was accomplished by calculating Maintainability Index for each application. Version control analysis was used to determine quality indicators during development and subsequent maintenance where new functionality was added in two steps.   The results show no major differences in maintainability in the initial applications. As more functionality is added the Maintainability Index decreases faster in the AngularJS application, indicating a steeper increase in complexity compared to the React application. Source code analysis reveals that changes in data flow requires significantly larger modifications of the AngularJS application due to its inherent architecture for data flow. We conclude that frameworks are useful when they facilitate development of known requirements but less so when applications and systems grow in size. / Ensidesapplikationer har historiskt sett påverkats av starka marknadskrafter som pådriver snabba utvecklingscykler och leve­rans­er. Detta medför att kvalitetskontroll och förändringsbar kod, som är viktiga fak­torer för förvaltningsbarhet, blir lidande. I denna rapport utvecklar vi två funktionellt ekvi­val­enta ensidesapplikationer med AngularJS och React samt jämför dessa applikationers för­valtningsbarhet enligt ISO/IEC 9126. AngularJS och React representerar två distinkta angreppsätt på webbutveckling, där AngularJS är ett ramverk med mycket färdig funk­tional­itet och React ett mindre bibliotek specialiserat på vyrendering. Kvalitets­jämförelsen utfördes genom att beräkna förvaltningsbarhetsindex för resp­ek­tive applikation. Ver­sions­­hanteringsanalys användes för att bestämma andra kvalitets­indi­kat­orer efter den initiala utvecklingen samt två efter­följande underhållsarbeten.   Resultaten visar inga markanta skillnader i förvaltningsbarhet för de initiala applikationerna. I takt med att mer funktionalitet lades till sjönk förvaltnings­barhetsindex snabbare för AngularJS-applikationen, vilket motsvarar en kraft­igare ökning i komplexitet jämfört med React-applikationen. Versions­hanteringsanalys visar att ändringar i dataflödet kräver större mod­ifika­tioner för AngularJS-applikationen på grund av dess förbestämda arki­tek­tur. Utifrån detta drar vi slutsatsen att ramverk är användbara när de under­stödjer utvecklingen mot kända krav men att deras nytta blir begränsad ju mer en applikation växer i storlek.

Assessing the source code quality of software objectively requires a well-defined model. Due to the distinct nature of each and every project, the definition of such a model is specific to the underlying type of paradigms used. A definer can pick metrics from standard norms to define measurements for qualitative assessment. Software projects develop over time and a wide variety of re-factorings is applied tothe code which makes the process temporal. In this thesis the temporal model was enhanced using methods known from financial markets and further evaluated using artificial neural networks with the goal of improving the prediction precision by learning from more detailed patterns. Subject to research was also if the combination of technical analysis and machine learning is viable and how to blend them. An in-depth selection of applicable instruments and algorithms and extensive experiments were run to approximate answers. It was found that enhanced patterns are of value for further processing by neural networks. Technical analysis however was not able to improve the results, although it is assumed that it can for an appropriately sizedproblem set.

Abstract Many software-intensive products and systems on the market today reveal a poor level of usability despite the availability of knowledge about how to develop good usability, namely user-centred design. Improving the status of user-centred design has proved to be a challenge in product development. An effective step to start out on the road to such improvements is to carry out a current state analysis. Our research problem was to learn how to perform an effective current state analysis, i.e. an assessment, of user-centred design processes to provide a basis for improvement action. As the main part of our research, we carried out five experimental assessments in industrial settings during the years 2000 and 2001. The main result of the research is a novel assessment approach. The objective of the approach is to provide a basis for improvement of the performance of user-centred design in individual product development projects. The particular features of the approach are a new user-centred design process model, a three-dimensional process performance model and implementation of the assessment in the form of a workshop with extensive participation by the project members. The user-centred design process model is method-independent, and consists of six processes that are defined through outcomes. The performance of processes is assessed from the viewpoints of quantity, quality, and integration. Our theoretical examinations show that different assessment categories can be identified depending on the different foci and purposes of an assessment. Moreover, it may even be appropriate to have different assessment approaches for different categories. In the category of our focus and purpose, i.e. 'assessment of user-centred design processes for performance improvement', the focus of an assessment should be in the substance rather than in the management of UCD processes. An assessment approach should be regarded as an artefact and it should be subject to ongoing refinement. An assessment should be an intervention that provides both an effective training session and a meaningful experience to the participants. Clarity in both the concepts and the results seems to take precedence over having standard reference models. In addition, we created a preliminary theory of usability capability. It identifies three dimensions of usability capability: user-centred design infrastructure, performance of user-centred design in product development projects and usability in business strategy. We also propose some new assessment artefacts for other assessment categories and contrast our research experience with established research frameworks.

Abstract Malmi et al. (2004) argue that the cost of quality (COQ) literature typically deals with manufacturing or service organizations in continuous or repetitive business processes in which identical or similar activities and work phases are repeated in the same sequence or order, batch after batch or customer after customer. Many modern businesses, such as the software business, are outright project based, or operate like a string of semi-independent projects characterized by unique resources, customized activity or work sequence order, and a predefined start and finish. COQ measuring and reporting are traditionally based on ex post calculations. In this study, an idea of real-time quality cost measurement will be developed and tested. The literature on real-time quality cost accounting is limited or even non-existent. The dissertation investigates whether it is possible to measure quality costs as a real-time basis in the software industry. The purpose is to develop a model for measuring quality costs on a real-time basis in software development. This is achieved by seeking answers to the research question how to measure quality costs on a real-time basis in the software industry. The research extends the current literature in three main respects. First, the study presents the idea of measuring quality costs in real-time basis. Second, a contribution is made by investigating how the characteristics of software business impact on the accounting of quality costs by presenting the nature and distinction of software business as well as its implications for software quality and applying quality cost measurement to the software business. Third, this study is expected to make a contribution by investigating how to use quality cost measurement as a management accounting tool in modern software business environment. The constructive research approach (CRA) proposed by Kasanen et al. (1993) is used in a case company, A, that develops and produces packaged software used in embedded products. Since it is not typically possible to pass semi-strong or strong market tests within a medium-term time span, the construction is tested by using more detailed nuances within the weak market test category suggested by Labro and Tuomela (2003) in order to analyse the level of progress of the construct. The possibility of constructing a real-time cost of quality measurement system developed in Case A is also tested in another case company (Case B) to make the weak market test stronger, and the boundary conditions how to construct such a system in a totally different working environment are charted. The results indicate that such a system could be constructed irrespective of the cost accounting environment or the software used. The anticipated contribution arises from the fact that the construct is a novelty that leads to a new means of quality cost accounting in software business (cf. Lukka 2000).

Abstract The quality of a software product depends largely on the quality of the process that is used to develop it. In small software companies, the development process may be informal or even ad hoc, which causes uncertainty and variation in the product quality. However, quality issues are as important in small companies as in their larger counterparts. To sustain their dynamics and competitiveness, small organizations need to concentrate on the most effective quality assurance methods. Software inspection is a proven method for improving product quality and it provides a very cost-effective way for small companies to improve their development processes. This study introduces a framework for adjusting the inspection process for the organization's specific needs and evaluating its capabilities. The main focus of this work, however, is on refining and improving the inspection process. The improvement is guided by concrete instructions that are documented as process patterns. The pattern approach has already been used successfully in several other areas of software engineering. Patterns aim at capturing the best practices of software development and transferring this knowledge between people or organizations. The framework for inspection process capability originates from the literature relating to different types of peer review methods and experiments with flexible and tool-supported inspections in small companies. Furthermore, generic process improvement models are studied to find a feasible structure for the framework. As a result of the analysis, the i3 capability model is introduced. The feasibility of the model has been investigated in real-life software organizations carrying out inspections. After the capability evaluation, the inspection process can be upgraded with the aid of improvement patterns, which provide structured and easy-to-follow guidelines for implementing improvements. An initial list of patterns, describing solutions to the most common problems confronted in the establishment of inspections, is extracted from related inspection research and an industrial experiment. The contributions of this study are, first, the new view of the inspection process, based on the fundamental activities that are performed during an inspection instead of a series of stages, as it is usually presented. An activity-based process description enables tailoring of the process for organization-specific needs and its targeted improvement. Second, the study introduces a practical, lightweight method for implementing the improvement. Patterns are especially suitable in companies where resources are limited and full-scale improvement programmes cannot be initiated. Furthermore, the generic process improvement models do not provide detailed information on how improvements should be carried out, and the pattern approach represents a promising method for that. Third, the inspection process currently does not have a very significant role in generic software process improvement models; this study helps in outlining the importance of inspections. A similar approach could be applied to other software subprocesses to enable their evaluation and improvement.