Approved for public release; distribution in unlimited. / The Department of Defense looks increasingly towards an interoperable and integrated system-of-systems to provide required military capability. Non-essential software complexity of a system-of-systems can have a greater negative impact in system behavior than a single system. Our current systems-of-systems tend to require a great deal of software maintenance and to be intolerant of even the most minor of changes with respect to negative perturbations in system behavior. In this thesis, we explore the benefits of developing a conceptual framework as the basis for the system-of-systems development. We examine the application of accepted software engineering practices for single-system developments to the more complex problem of system-of-systems development. Using the Ballistic Missile Defense System as a case study, we present an abstract framework from which we can reason about the system-of-systems. We develop a conceptual software architecture that represents a logical organization of proposed software modules. We map the functionality of the system to conceptual software components with coordination and data exchanges handled by conceptual connectors. Finally, we assess our work to determine the feasibility of applying the conceptual framework techniques described in this thesis to system-of-systems acquisitions with the objective of reducing accidental complexity and controlling essential complexity. / Civilian, Missile Defense Agency, Washington, D.C.

Recent research within the field of Software Engineering have used GitHub, the largest hub for open source projects with almost 20 million users and 57 million repositories, to mine large amounts of source code to get more trustworthy results when developing machine and deep learning models. Mining GitHub comes with many challenges since the dataset is large and the data does not only contain quality software projects. In this project, we try to mine projects from GitHub based on earlier research by others and try to validate the quality by comparing the projects with a small subset of quality projects with the help of software complexity metrics.

This thesis addresses design and development associated problems identified within theplatform-game genre. The problem described originates from the fluctuating curve ofinterest towards the platform-game genre that can be observed between the 1980’s andtoday. The problem stated in this thesis is that modern platform-game developers mayoften overlook and –or deprioritize important design and gameplay related componentsthat we find reoccurring in previously popular games within the genre.This thesis strives to address such problems by decomposing the developmentprocess of a platform game into a light framework titled Implementation categories. Allincluded categories represent a set of design and development related platform-gamecomponents – primarily identified through previous research in the field. In order tocreate an understanding of each category’s complexity - as well as account for thepossibilities to use the categories as a guideline when developing a platform game - aprototype game was developed. The Implementation categories included in theprototype was then measured with a set of software complexity metrics. This thesis willmotivate and explain the selection of implementation categories, account for the usageof software complexity metrics as well as present a detailed documentation of theprototype development.The result of this thesis is a thorough presentation of the Implementation categories -attached with complexity examples for each category as well as a complete gameprototype. The complete results of this thesis will hopefully be of assistance in smallscale,independent or academic game projects in regard of design, decision making,prioritization and time planning.

Dealing with the complexity of large-scale systems can be a challenge for even the most experienced software architects and developers. Large-scale software systems can contain millions of elements, which interact to achieve the system functionality. Managing and representing the complexity involved in the interaction of these elements is a difficult task. We propose an approach for analyzing the reusability, maintainability and complexity of such a complex large-scale software system. Reducing the dependencies between the subsystems increase the reusability and decrease the efforts needed to maintain the system thus reducing the complexity of the system. Coupling is an attribute that summarizes the degree of interdependence or connectivity among subsystems and within subsystems. When used in conjunction with measures of other attributes, coupling can contribute to an assessment or prediction of software quality. We developed a set of metrics for measuring the coupling at the subsystems level in a large-scale software system as a part of this work. These metrics do not take into account the complexity internal to a subsystem and considers a subsystem as a single entity. Such a dependency metric gives an opportunity to predict the cost and effort needed to maintain the system and also to predict the reusability of the system parts. It also predicts the complexity of the system. More the dependency, higher is the cost to maintain and reuse the software. Also the complexity and cost of the system will be high if the coupling is high. We built a large-scale system and implemented these research ideas and analyzed how these measures help in minimizing the complexity and system cost. We also proved that these coupling measures help in re-factoring of the system 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

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

This paper addresses the question formulation “Is it possible to implement automated testing in an existing client-server game in order to pinpoint faults and achieve credibility to tests?” The gaming industry’s goal, in most cases, is to release games that appeal to both their financial goals and the enjoyment factor of the players. In order to fulfill these goals, the game will need to function properly and the process to assure this is testing the game to find possible faults. This process is time and cost consuming in an exponential rate in accordance to game extensiveness, which makes this problem a very important decision in the process of development. The problem is most commonly tackled by using massive manual testing session, called alpha or beta sessions. In these session the game is at an early stage of development and gets released to a set player base to test and report issues encountered. We believe that the process of testing games could be more effective by utilizing automated testing. This thesis will investigate the possibilities to our claim. The result is a visual representation of the tests we managed to apply, while focusing on the client-server connectivity of Quake 3 and a graph of measurements for our improvised fault localization. This paper describes a solution in form of automated tests within a existing client-server game and a start to what could be early stages of a pattern obtained throughout this project.

Systems of distributed character are increasing in size and becoming more complex. Managing and adapting to constant changes of requirements is a challenge during the entire system development life cycle. While new functionalities are implemented, the software may change in design and may lead to poor software quality and increased system complexity. This thesis focuses on tackling the complexity issue in a distributed Electronic Warfare system used in military aircraft. The system consists of a server and several clients which acts as publishers or subscribers for different events sent in the system. The communication is based on unicast and uses a publish/subscribe pattern for the client nodes to register as publishers or subscribers to the server. The system is created to handle message passing in high rate and is sensitive for message delays. Due to this, the system is dependent on a reliable network structure with a continuous necessity for development. An implementation of a multicast prototype will be replacing the topic-specific unicast communication and the publish/subscribe registration process to the server. The system will be evaluated by a comparison of the old communication version with the new multicast implementation using software metrics. The result is to evaluate if the behavior and functionality of the distributed Electronic Warfare system change. / System av distribuerad karaktär ökar i storlek och blir alltmer komplex. Att hantera och anpassa sig till ständiga kravändringar är emellertid en utmaning under hela systemets utvecklingsprocess. Medan nya funktioner implementeras kan mjukvaran ändras i design vilket kan leda till dålig programkvalitet och ökad systemkomplexitet. Denna rapport fokuserar på att hantera komplexiteten i ett distribuerat telekrigföringssystem som används i militära flygplan. Systemet består av en server och flera klienter som publicerar och prenumererar för olika typer av meddelanden som skickas i systemet. Kommunikationen baseras på enkelsändning och använder ett publish/subscribe meddelandemönster där klienterna registrerar sig som publicerare eller prenumeranter till servern. Systemet är skapat för att kunna hantera höga meddelandehastigheter och har låg tolerans för meddelandeförseningar. På grund av detta är tillförlitlighet i nätverksstrukturen ett essentiellt kvalitetsattribut då nätverket är i behov av en ständig utveckling. En prototyp av multisändning kommer att implementeras och ersätta kommunikationen baserad på enkelsändning och publish/subscribe registreringsprocessen till servern. Systemet kommer att utvärderas genom en jämförelse av den gamla kommunikationsversionen av systemet med den nya multicast-implementeringen med hjälp av mjukvarukomplexitetsmätningar. Resultatet är att utvärdera om beteendet och funktionaliteten hos det distribuerade telekrigföringssystemet ändras.