Viljan att hålla en hög kvalitet på den kod som skrivs vid utveckling av system och applikationerär inte något nytt i utvecklingsvärlden. Flera större företag använder sig av olika mått för attmäta kvaliteten på koden i sina system med målet att hålla en hög driftsäkerhet.Trafikverket är en statlig myndighet som ansvarar för driften av bland annat de system somhåller igång Sveriges järnvägsnät. Eftersom systemen fyller en viktig del i att säkra driften ochse till att tågpositioner, planering av avgångar och hantering av driftstörningar fungerar dygnetrunt för hela landet anser de att det är viktigt att sträva efter att hålla en hög kvalitet påsystemen.Syftet med det här examensarbetet var att ta reda på vilka mått som kan vara möjliga attanvända under systemutvecklingsprocessen för att mäta kvaliteten på kod och hur måtten kananvändas för att öka kvaliteten på IT-lösningar. Detta för att redan på ett tidigt stadie kunnamäta kvaliteten på den kod som skrivs i både befintliga och nyutvecklade system.Studien är en fallstudie som utfördes på Trafikverket, de olika måtten som undersöktes varcode coverage, nivån på maintainability index och antalet inrapporterade incidenter för varjesystem. Mätningar utfördes på sju av Trafikverkets system som i analysen jämfördes motantalet rapporterade incidenter. Intervjuer utfördes för att ge en bild över hur arbetssättet vidutveckling kan påverka kvaliteten. Genom litteraturstudier kom det fram ett mått som inte kundeanvändas praktiskt i det här fallet men är högst intressant, detta är cyclomatic complexity somfinns som en del av maintainability index men som även separat påverkar möjligheten att skrivaenhetstest.Resultaten av studien visar att måtten är användbara för ändamålet men bör inte användassom enskilda mått för att mäta kvalitet eftersom de fyller olika funktioner. Det är viktigt attarbetssättet runt utveckling genomförs enligt en tydlig struktur och att utvecklarna både harkunskap om hur man arbetar med enhetstest och följer kodprinciper för strukturen. Tydligakopplingar mellan nivån på code coverage och inflödet av incidenter kunde ses i de undersöktasystemen där hög code coverage ger ett lägre inflöde av incidenter. Ingen korrelation mellanmaintainability index och incidenter kunde hittas. / The desire to ascertain a high level of quality on the code written during the development of systems and applications is not something new in the system development world. Several larger companies use different kinds of metrics to measure the quality of the code in their systems with the goal of maintaining high reliability and quality.Trafikverket is a government authority responsible for the operation of the system that keeps the Swedish railroad running. Their systems play an important part in ensuring the operation and to ensure that train positions, the planning of departures and error handling works around the clock for the entire country, they find it important and strive to maintain the high quality of the systems.The aim of this thesis was to find out which measurements may be possible to use during the system development process to measure the quality of the code and how measurements can be used to increase the quality of IT solutions. It should be possible to measure the quality of the code that is written in both existing and newly developed systems at an early stage. The study is a case study conducted at Trafikverket, the metrics that were examined were code coverage, the level of maintainability index and the number of reported incidents for each system. Measurements were performed on seven of Trafikverket's systems. In the analysis the measurements were compared to the number of reported incidents. Interviews were conducted to provide a picture of how the operation of the development may affect the quality. Through literature studies we discovered a metric that could not be used practically in this case, this was cyclomatic complexity, it is available as part of the maintainability index, but also separately affects the ability to write unit tests. The results of the study show that the measurements are useful for this purpose but should not be used as individual metrics to measure quality because they all have their own function. A clear link between the level of the code coverage and the number of incidents could be observed in the investigated systems where high code coverage provides a lower rate of incidents. No correlation between maintainability index and incidents could be found.

We live in a society where automatization is becoming more common, whether it be cars or artificial intelligence. Software needs to be updated using patches, however, these patches have the possibility of breaking components. This study takes such a patch in the context of Ericsson, identifies what needs to be tested, investigates whether the tests can be automated and assesses how maintainable they are. Interviews were used for the identification of system and software parts in need of testing. Then tests were implemented in an automated test suite to test functionality of either a system or software. The goal was to reduce time of troubleshooting for employees without interrupting sessions for users as well as set up a working test suite. When the automated testing is completed and implemented in the test suite, the study is concluded by measuring the maintainability of the scripts using both metrics and human assessment through interviews. The result showed the testing suite proved maintainable, both from the metric point of view and from human assessment.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg 2017 / The study assesses the drilling, loading and trucking stages of the mining cycle of an iron ore mine situated in the Northern Cape province of South Africa for the period of 1 January to 30 June 2011. The purpose of this study is to investigate the effect of increasing reliability and maintainability of mining equipment in an effort to increase throughput of iron ore. The data processing indicated that both availability and utilisation are contributing to the sub-optimal performance of the mine. Data regarding reliability (MTBF), maintainability (MTTR), planned and unplanned maintenance was analysed, and this provided input for the simulation model. The intention of the simulation model is to simulate scenarios of proposed improvement in MTBF and MTTR through increasing planned maintenance activities. A simulation model provides insight regarding where to invest in interventions. It is determined that the drilling equipment is the problem area. / MT2018

É rara a preocupação com a qualidade de implementação de software. Pode-se observar que as estruturas internas dos softwares são freqüentemente complexas e desorganizadas, especialmente no caso dos softwares que são ditos orientados a objetos. Essa complexidade afeta diretamente a manutenibilidade e a susceptibilidade a erros, dificultando a alteração e a adição de novas funcionalidades aos softwares. As próprias alterações, inerentes aos softwares, os tornam mais complexos, o que agrava o problema. Neste contexto, acredita-se que o controle da complexidade pode levar a produtos de software de melhor qualidade. Assim, trata-se neste trabalho da manutenção preventiva, implementada por meio de inspeções, refatorações e análise de métricas. São estudadas falhas de manutenibilidade em uma amostra de programas orientados a objetos e, a partir dos resultados, são propostos artefatos de apoio para um processo de inspeção de software e modelos para os produtos de trabalho gerados nesse processo. Propõe-se o uso da técnica de leitura PBR (Leitura Baseada em Perspectivas) como uma maneira de se melhorar a detecção de falhas de manutenibilidade. Finalmente, a proposta deste trabalho foi validada por meio de um estudo de caso / The commitment with the quality of software implemetation is rare. It\'s possible to observe that the software internal structures are frequently complex and disorganized, especially when talking about software that is said to be object-oriented. This complexity directly affects maintainability and error proneness, making it difficult to change and to add new functionalities to software. Changes themselves, that are inherent in software, make it more complex, and that makes the problem more serious. In this context, it\'s believed that the control of complexity can lead to better quality software products. Thus, the subject of this work is the preventive maintenance, implemented by means of inspections, refactoring and metric analysis. Maintenance flaws were studied in a sample of object-oriented programs and, based on the results, support artifacts for an inspection process were proposed, along with models of work products for this process. The use of PBR (Perspective-Based Reading) technique is proposed as a means of improving the detection of maintenance flaws. Finally, the proposal of this work is validated through a case study

After the book, Design Patterns: Elements of Reusable Object-Oriented Software was published in 1994, usage of design patterns in object-oriented (OO) programming has been investigated by many researchers. However, the effects of design patterns on non-object oriented (non-OO) programming have not been analyzed too much in the literature. This study focuses on various design pattern implementations using non OO programming and investigates the benefits of design patterns upon real-time software. In order to evaluate the results, specific quality metrics were selected and performance of traditionally developed software was compared with that of software developed using design patterns.

Over the last few decades the design of high lift devices has become a very important part of the total aircraft design process. Reviews of the design process are performed on a regular basis, with the intent to improve and optimize the design process. This thesis describes a new and innovative methodology for the design and evaluation of mechanisms for Trailing Edge High-Lift devices. The initial research reviewed existing High-Lift device design methodologies and current flap systems used on existing commercial transport aircraft. This revealed the need for a design methodology that could improve the design process of High-Lift devices, moving away from the conventional "trial and error" design approach, and cover a wider range of design attributes. This new methodology includes the use of the innovative design tool called SYNAMEC. This is a state-of-the-art engineering design tool for the synthesis and optimizations of aeronautical mechanisms. The new multidisciplinary design methodology also looks into issues not usually associated with the initial stages of the design process, such as Maintainability, Reliability, Weight and Cost. The availability of the SYNAMEC design tool and its ability to perform Synthesis and Optimization of mechanisms led to it being used as an important module in the development of the new design methodology. The SYNAMEC tool allows designers to assess more mechanisms in a given time than the traditional design methodologies. A validation of the new methodology was performed and showed that creditable results were achieved. A case study was performed on the ATRA - Advance Transport Regional Aircraft, a Cranfield University design project, to apply the design methodology and select from within a group of viable solutions the most suitable type of mechanism for the Variable Camber Wing concept initially defined for the aircraft. The results show that the most appropriate mechanism type for the ATRA Variable Camber Wing is the Link /Track Mechanism. It also demonstrated how a wide range of design attributes can now be considered at a much earlier stage of the design.

The availability, or reliability, of an engineering component greatly influences the operational cost and safety characteristics of a modern system over its life-cycle. Until recently, the reliance on past empirical data has been the industry-standard practice to develop maintenance policies that provide the minimum level of system reliability. Because such empirically-derived policies are vulnerable to unforeseen or fast-changing external factors, recent advancements in the study of topic on maintenance, which is known as optimal maintenance problem, has gained considerable interest as a legitimate area of research. An extensive body of applicable work is available, ranging from those concerned with identifying maintenance policies aimed at providing required system availability at minimum possible cost, to topics on imperfect maintenance of multi-unit system under dependencies. Nonetheless, these existing mathematical approaches to solve for optimal maintenance policies must be treated with caution when considered for broader applications, as they are accompanied by specialized treatments to ease the mathematical derivation of unknown functions in both objective function and constraint for a given optimal maintenance problem. These unknown functions are defined as reliability measures in this thesis, and theses measures (e.g., expected number of failures, system renewal cycle, expected system up time, etc.) do not often lend themselves to possess closed-form formulas. It is thus quite common to impose simplifying assumptions on input probability distributions of components' lifetime or repair policies. Simplifying the complex structure of a multi-unit system to a k-out-of-n system by neglecting any sources of dependencies is another commonly practiced technique intended to increase the mathematical tractability of a particular model. This dissertation presents a proposal for an alternative methodology to solve optimal maintenance problems by aiming to achieve the same end-goals as Reliability Centered Maintenance (RCM). RCM was first introduced to the aircraft industry in an attempt to bridge the gap between the empirically-driven and theory-driven approaches to establishing optimal maintenance policies. Under RCM, qualitative processes that enable the prioritizing of functions based on the criticality and influence would be combined with mathematical modeling to obtain the optimal maintenance policies. Where this thesis work deviates from RCM is its proposal to directly apply quantitative processes to model the reliability measures in optimal maintenance problem. First, Monte Carlo (MC) simulation, in conjunction with a pre-determined Design of Experiments (DOE) table, can be used as a numerical means of obtaining the corresponding discrete simulated outcomes of the reliability measures based on the combination of decision variables (e.g., periodic preventive maintenance interval, trigger age for opportunistic maintenance, etc.). These discrete simulation results can then be regressed as Response Surface Equations (RSEs) with respect to the decision variables. Such an approach to represent the reliability measures with continuous surrogate functions (i.e., the RSEs) not only enables the application of the numerical optimization technique to solve for optimal maintenance policies, but also obviates the need to make mathematical assumptions or impose over-simplifications on the structure of a multi-unit system for the sake of mathematical tractability. The applicability of the proposed methodology to a real-world optimal maintenance problem is showcased through its application to a Time Limited Dispatch (TLD) of Full Authority Digital Engine Control (FADEC) system. In broader terms, this proof-of-concept exercise can be described as a constrained optimization problem, whose objective is to identify the optimal system inspection interval that guarantees a certain level of availability for a multi-unit system. A variety of reputable numerical techniques were used to model the problem as accurately as possible, including algorithms for the MC simulation, imperfect maintenance model from quasi renewal processes, repair time simulation, and state transition rules. Variance Reduction Techniques (VRTs) were also used in an effort to enhance MC simulation efficiency. After accurate MC simulation results are obtained, the RSEs are generated based on the goodness-of-fit measure to yield as parsimonious model as possible to construct the optimization problem. Under the assumption of constant failure rate for lifetime distributions, the inspection interval from the proposed methodology was found to be consistent with the one from the common approach used in industry that leverages Continuous Time Markov Chain (CTMC). While the latter does not consider maintenance cost settings, the proposed methodology enables an operator to consider different types of maintenance cost settings, e.g., inspection cost, system corrective maintenance cost, etc., to result in more flexible maintenance policies. When the proposed methodology was applied to the same TLD of FADEC example, but under the more generalized assumption of strictly Increasing Failure Rate (IFR) for lifetime distribution, it was shown to successfully capture component wear-out, as well as the economic dependencies among the system components.

Motion controlled games can be a good physical activity for children, but the game has to be fun and engaging. We have, with a starting point in an existing base game, developed an achievement module which follows certain code standards to make it easier to understand, and to make hand overs of the code smoother. More work on the rest of the game has also been done to make it more engaging, while clean up of the existing code to follow the same standards.

Over the last few decades the design of high lift devices has become a very important part of the total aircraft design process. Reviews of the design process are performed on a regular basis, with the intent to improve and optimize the design process. This thesis describes a new and innovative methodology for the design and evaluation of mechanisms for Trailing Edge High-Lift devices. The initial research reviewed existing High-Lift device design methodologies and current flap systems used on existing commercial transport aircraft. This revealed the need for a design methodology that could improve the design process of High-Lift devices, moving away from the conventional "trial and error" design approach, and cover a wider range of design attributes. This new methodology includes the use of the innovative design tool called SYNAMEC. This is a state-of-the-art engineering design tool for the synthesis and optimizations of aeronautical mechanisms. The new multidisciplinary design methodology also looks into issues not usually associated with the initial stages of the design process, such as Maintainability, Reliability, Weight and Cost. The availability of the SYNAMEC design tool and its ability to perform Synthesis and Optimization of mechanisms led to it being used as an important module in the development of the new design methodology. The SYNAMEC tool allows designers to assess more mechanisms in a given time than the traditional design methodologies. A validation of the new methodology was performed and showed that creditable results were achieved. A case study was performed on the ATRA - Advance Transport Regional Aircraft, a Cranfield University design project, to apply the design methodology and select from within a group of viable solutions the most suitable type of mechanism for the Variable Camber Wing concept initially defined for the aircraft. The results show that the most appropriate mechanism type for the ATRA Variable Camber Wing is the Link /Track Mechanism. It also demonstrated how a wide range of design attributes can now be considered at a much earlier stage of the design.

É rara a preocupação com a qualidade de implementação de software. Pode-se observar que as estruturas internas dos softwares são freqüentemente complexas e desorganizadas, especialmente no caso dos softwares que são ditos orientados a objetos. Essa complexidade afeta diretamente a manutenibilidade e a susceptibilidade a erros, dificultando a alteração e a adição de novas funcionalidades aos softwares. As próprias alterações, inerentes aos softwares, os tornam mais complexos, o que agrava o problema. Neste contexto, acredita-se que o controle da complexidade pode levar a produtos de software de melhor qualidade. Assim, trata-se neste trabalho da manutenção preventiva, implementada por meio de inspeções, refatorações e análise de métricas. São estudadas falhas de manutenibilidade em uma amostra de programas orientados a objetos e, a partir dos resultados, são propostos artefatos de apoio para um processo de inspeção de software e modelos para os produtos de trabalho gerados nesse processo. Propõe-se o uso da técnica de leitura PBR (Leitura Baseada em Perspectivas) como uma maneira de se melhorar a detecção de falhas de manutenibilidade. Finalmente, a proposta deste trabalho foi validada por meio de um estudo de caso / The commitment with the quality of software implemetation is rare. It\'s possible to observe that the software internal structures are frequently complex and disorganized, especially when talking about software that is said to be object-oriented. This complexity directly affects maintainability and error proneness, making it difficult to change and to add new functionalities to software. Changes themselves, that are inherent in software, make it more complex, and that makes the problem more serious. In this context, it\'s believed that the control of complexity can lead to better quality software products. Thus, the subject of this work is the preventive maintenance, implemented by means of inspections, refactoring and metric analysis. Maintenance flaws were studied in a sample of object-oriented programs and, based on the results, support artifacts for an inspection process were proposed, along with models of work products for this process. The use of PBR (Perspective-Based Reading) technique is proposed as a means of improving the detection of maintenance flaws. Finally, the proposal of this work is validated through a case study