In this thesis, we benchmark the Cognitive Radios Test System version 2.0 (CRTSv.2) to analyze its software performance with respect to its internal structure and design choices. With the help of system monitoring and profiling tools, CRTSv.2 is tested to quantitatively evaluate its features and understand its shortcomings. With the help of GNU Radio, a popular, easy-to-use software radios framework, we ascertain that CRTSv.2 has a low memory footprint, fewer dependencies and overall, is a lightweight framework that can potentially be used for real-time signal processing. Several open-source measurement tools such as valgrind, perf, top, etc. are used to evaluate the CPU utilization, memory footprint and to postulate the origins of latencies. Based on our evaluation, we observe that CRTSv.2 shows a CPU utilization of approximately 9% whereas GNU Radio is 59%. CRTSv.2 has lower heap memory consumption of approximately 3MB to GNU Radio's 25MB. This study establishes a methodology to evaluate the performance of two SDR frameworks systematically and quantitatively. / Master of Science / When picking the best person for the job, we rely on the person's performance in past projects of a similar nature. The same can be said for software. Software radios provide the capability to perform signal processing functions in software, making them prime candidates towards solving modern problems such as spectrum scarcity, internet-of-things(IoT) adoption, vehicle-to-vehicle communication etc. In order to operate and configure software radios, software frameworks are provided that let the user make changes to the waveform, perform signal processing and data management. In this thesis, we consider two such frameworks,GNU Radio and CRTSv.2. A software performance evaluation is conducted to assess framework overheads contributing to operation of an orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. This provides a quantitative analysis of a signals-specific use case which can be used by researchers to evaluate the optimal framework for research. This analysis can be generalized for different signal processing capabilities by understanding the total framework overhead removed from signal processing costs.

In recent years studies have been conducted which suggest that taking an architecture first approach to managing large software projects can reduce a significant amount of the uncertainty present in project estimates. As the project progresses, more concrete information is known about the planned system and less risk is present. However, the rate at which risk is alleviated varies across the life-cycle. Research suggests that there exists a significant drop off in risk when the architecture is developed. Software risk assessment techniques have been developed which attempt to quantify the amount of risk that varying uncertainties convey to a software project. These techniques can be applied to architecture specific issues to show that in many cases, conducting an architecture centric approach to development will remove more risk than the cost of developing the architecture. By committing to developing the architecture prior to the formal estimation process, specific risks can be more tightly bounded, or even removed from the project. The premise presented here is that through the process of architecture-centric management, it is possible to remove substantial risk from the project. This decrease in risk exceeds that at other phases of the life-cycle, especially in comparison of the effort involved. Notably, at architecture, a sufficient amount knowledge is gained by which effort estimations may be tightly bounded, yet the project is early enough in the life-cycle for proper planning and scheduling. Thus, risk is mitigated through the increase in knowledge and the ability to maintain options at an early point. Further, architecture development and evaluation has been shown to incorporate quality factors normally insufficiently considered in the system design. The approach taken here is to consider specific knowledge gained through the architecting process and how this is reflected in parametric effort estimation models. This added knowledge is directly reflected in risk reduction. Drawing on experience of architecture researchers as well as project managers employing this approach, this thesis considers what benefits to the software development process are gained by taking this approach. Noting a strong reluctance of owners to incorporate solid software engineering practices, the thesis concludes with an outline for an experiment which goes about proving the reduction in risk at architecture exceeds the cost of that development. / Master of Science

Software Defined Radios are computer based systems that emulate the behavior of traditional radio systems by processing digitized radio signals. A SDR replaces the traditional fixed hardware radio with a system that may be reconfigured, both during operation to provide greater flexibility and by providing software upgrades to add new capabilities without requiring new hardware. These are powerful reasons for using SDR technology; however this flexibility comes at the cost of increased hardware cost and greater power consumption compared with traditional hardware radios. This report presents measurements of memory and processor usage for a Software Communication Architecture (SCA) waveform running on an OMAP starter kit and a desktop PC. The process used to build software, originally targeted for a desktop computer, on an embedded machine with a different processor architecture is described. OSSIE, an open source SCA implementation developed at Virginia Tech, was ported to the ARM processor by adding support for building OSSIE into the OpenEmbedded build system. Once the port for the OMAP starter kit was complete, it became possible to easily re-target OSSIE for a variety of other hardware platforms. For testing purposes a simple waveform capable of transmitting several common digital modulation formats was developed. A SCA device for the Universal Software Radio Peripheral was developed to interface the waveform to the antenna. One method to reduce the cost and power consumption is to limit the amount of memory used in the radio. This reduces both cost and power consumption. This report describes the memory manager portion of the Linux kernel and how it helps reduce the memory used by the system. The exmap tool for accurately measuring memory usage is described and used to measure the memory usage of the OSSIE based test waveform. These techniques help radio developers measure and reduce the amount of memory required for the SDR, reducing system cost and power consumption. Finally, the oprofile was used to measure relative processor usage of the waveform components. Oprofile can also provide details about specific sections of waveform code that use the most processor cycles. This information helps the radio designer reduce the number of processing cycles required. This allows the hardware to use a lower speed part, or add more capability to the radio design. / Master of Science

Software Livre é software fornecido com código fonte, e que pode ser livremente usado, modificado e redistribuído. Projetos de Software Livre são organizações virtuais formadas por indivíduos que trabalham juntos no desenvolvimento de um software livre específico. Estes indivíduos trabalham geograficamente dispersos, utilizando ferramentas simples para coordenar e comunicar seu trabalho através da Internet. Este trabalho analisa esses projetos do ponto de vista de seu processo de software; em outras palavras, analisa as atividades que realizam para produzir, gerenciar e garantir a qualidade do seu software. Na parte inicial do trabalho é feita uma extensa revisão bibliográfica, comentando os principais trabalhos na área, e são detalhadas as características principais dos projetos de software livre. O conteúdo principal deste trabalho resulta de dois anos de participação ativa na comunidade, e de um levantamento realizado através de questionário, detalhando mais de quinhentos projetos diferentes. São apresentadas treze hipóteses experimentais, e os resultados do questionário são discutidos no contexto destas hipóteses. Dos projetos avaliados nesse levantamento, algumas características comuns foram avaliadas. As equipes da grande maioria dos projetos são pequenas, tendo menos de cinco participantes. Além disso, existe uma distribuição equilibrada entre algumas formas de organização descritas na literatura, incluindo o \'ditador benevolente\' de Eric S. Raymond e o \'comité\' exemplificado pelo projeto Apache. Dentre um conjunto de domínios de aplicação determinados, os projetos de software livre se concentram nas áreas de engenharia e desenvolvimento de software, redes e segurança, e aplicações multimídia. Com relação às atividades do processo de software, pode-se dizer que a maioria dos projetos tem requisitos fundamentalmente definidos pelos seus autores, e que a base de usuários de grande parte dos softwares é composta dos seus desenvolvedores e da comunidade de software livre. Uma parcela significativa dos projetos baseia-se em outros softwares pré-existentes, e em padrões publicados previamente. Pouca ênfase é dada à usabilidade, assim como às atividades de garantia de qualidade convencionais. Surpreendentemente, também recebem pouca atenção as atividades de revisão de código e teste sistemático. Entre as ferramentas que os projetos utilizam, se destacam as listas de discussão e os sistemas de controle de versão. Foi estabelecida uma correlação entre a dimensão da equipe do projeto e as atividades de engenharia de software que realiza, mas não se confirmou um vínculo entre estas atividades e a idade do projeto. Foram também estabelecidas relações entre o número de linhas de código do software do projeto e a sua idade, tamanho e domínio de aplicação. Estes resultados são exibidos neste trabalho, e estarão publicamente disponíveis no site Web do projeto. O trabalho conclui descrevendo partes essenciais do processo de software em projetos de software livre, e oferecendo sugestões para trabalhos posteriores. / Free Software (or Open Source) is software provided with source code that may be freely used, modified and redistributed. Free Software Projects are virtual communities of developers that work on a specific free software product. These developers work geographically dispersed, using simple tools to communicate and coordinate their actions over the Internet. This work analyzes these projects with respect to their software process; in other words, the activities they do to produce, manage and ensure the quality of their software. In the initial sections, I perform a large review of related work in this field, and provide an overview of the main characteristics of free software projects. The main contents of this dissertation is based on two years of participation in free software projects, and on a survey based on a questionnaire that describes over five hundred different free software projects. 1 present thirteen initial hypothesis, using them as a framework to analyze the results of the survey. Among the projects evaluated in this survey, some common aspeets were observed. For instance, most projects have a small team, with less than five developers. I also found a balanced distribution of leadership systems described in other works, including Eric Raymond\'s \'benevolent dictator\' and the committee exemplified by the Apache project. The domains in which these projects tend to concentrate are software engineering and development, networks and security, and multimédia applications. Concerning the software process activities, most projects have their functional requirements established by their authors: the user base for most of the projects includes the development team and the free software community. A large proportion of the projects surveyed are based on pre-existing software, or on previously published standards. Little emphasis is placed on usability and conventional fornis of quality assurance. Remarkably, this lack of emphasis on conventional process includes activities like review and testing. Among the tools used by the projects, mailing lists and versioning systems such as CVS come out ahead by a strong margin. A correlation was identified between the size of the project\'s team and the software engineering activities that it realizes, but I could not establish a link between the age of the project and these activities. Other correlations were established between the size of the project\'s codebase (in terms of lines of code) and its age, size and application domain. The dissertation concludes describing essential parts of the software process in free software projects, and offering suggestions for future work.

Software Livre é software fornecido com código fonte, e que pode ser livremente usado, modificado e redistribuído. Projetos de Software Livre são organizações virtuais formadas por indivíduos que trabalham juntos no desenvolvimento de um software livre específico. Estes indivíduos trabalham geograficamente dispersos, utilizando ferramentas simples para coordenar e comunicar seu trabalho através da Internet. Este trabalho analisa esses projetos do ponto de vista de seu processo de software; em outras palavras, analisa as atividades que realizam para produzir, gerenciar e garantir a qualidade do seu software. Na parte inicial do trabalho é feita uma extensa revisão bibliográfica, comentando os principais trabalhos na área, e são detalhadas as características principais dos projetos de software livre. O conteúdo principal deste trabalho resulta de dois anos de participação ativa na comunidade, e de um levantamento realizado através de questionário, detalhando mais de quinhentos projetos diferentes. São apresentadas treze hipóteses experimentais, e os resultados do questionário são discutidos no contexto destas hipóteses. Dos projetos avaliados nesse levantamento, algumas características comuns foram avaliadas. As equipes da grande maioria dos projetos são pequenas, tendo menos de cinco participantes. Além disso, existe uma distribuição equilibrada entre algumas formas de organização descritas na literatura, incluindo o \'ditador benevolente\' de Eric S. Raymond e o \'comité\' exemplificado pelo projeto Apache. Dentre um conjunto de domínios de aplicação determinados, os projetos de software livre se concentram nas áreas de engenharia e desenvolvimento de software, redes e segurança, e aplicações multimídia. Com relação às atividades do processo de software, pode-se dizer que a maioria dos projetos tem requisitos fundamentalmente definidos pelos seus autores, e que a base de usuários de grande parte dos softwares é composta dos seus desenvolvedores e da comunidade de software livre. Uma parcela significativa dos projetos baseia-se em outros softwares pré-existentes, e em padrões publicados previamente. Pouca ênfase é dada à usabilidade, assim como às atividades de garantia de qualidade convencionais. Surpreendentemente, também recebem pouca atenção as atividades de revisão de código e teste sistemático. Entre as ferramentas que os projetos utilizam, se destacam as listas de discussão e os sistemas de controle de versão. Foi estabelecida uma correlação entre a dimensão da equipe do projeto e as atividades de engenharia de software que realiza, mas não se confirmou um vínculo entre estas atividades e a idade do projeto. Foram também estabelecidas relações entre o número de linhas de código do software do projeto e a sua idade, tamanho e domínio de aplicação. Estes resultados são exibidos neste trabalho, e estarão publicamente disponíveis no site Web do projeto. O trabalho conclui descrevendo partes essenciais do processo de software em projetos de software livre, e oferecendo sugestões para trabalhos posteriores. / Free Software (or Open Source) is software provided with source code that may be freely used, modified and redistributed. Free Software Projects are virtual communities of developers that work on a specific free software product. These developers work geographically dispersed, using simple tools to communicate and coordinate their actions over the Internet. This work analyzes these projects with respect to their software process; in other words, the activities they do to produce, manage and ensure the quality of their software. In the initial sections, I perform a large review of related work in this field, and provide an overview of the main characteristics of free software projects. The main contents of this dissertation is based on two years of participation in free software projects, and on a survey based on a questionnaire that describes over five hundred different free software projects. 1 present thirteen initial hypothesis, using them as a framework to analyze the results of the survey. Among the projects evaluated in this survey, some common aspeets were observed. For instance, most projects have a small team, with less than five developers. I also found a balanced distribution of leadership systems described in other works, including Eric Raymond\'s \'benevolent dictator\' and the committee exemplified by the Apache project. The domains in which these projects tend to concentrate are software engineering and development, networks and security, and multimédia applications. Concerning the software process activities, most projects have their functional requirements established by their authors: the user base for most of the projects includes the development team and the free software community. A large proportion of the projects surveyed are based on pre-existing software, or on previously published standards. Little emphasis is placed on usability and conventional fornis of quality assurance. Remarkably, this lack of emphasis on conventional process includes activities like review and testing. Among the tools used by the projects, mailing lists and versioning systems such as CVS come out ahead by a strong margin. A correlation was identified between the size of the project\'s team and the software engineering activities that it realizes, but I could not establish a link between the age of the project and these activities. Other correlations were established between the size of the project\'s codebase (in terms of lines of code) and its age, size and application domain. The dissertation concludes describing essential parts of the software process in free software projects, and offering suggestions for future work.

It is widely acknowledged that there is a shortage of software developers with the right skills and knowledge. In respect of their university education, students want to take courses and carry out projects that clearly relate to their lives and their goals. The software development industry on the other hand, expects students to be educated in courses and projects, which are relevant for their professional career and equip them to be well-prepared for the workplace. In the middle, between the students and the industry, is the university that is expected to meet the needs of the students on the one side and the software industry on the other side. The unique contribution of this research is the development of a framework for relevant software development education by addressing the question: How can universities ensure that software development education provides knowledge and skill sets that are relevant to both the software development industry and software development students? The literature study investigates the software development class, focusing on the students and the educators. Furthermore, a review of the software development workplace is done with attention to the software developers and their employers. The problems and challenges facing three role players in software development education, namely the students, the university and the industry are investigated. Lastly, the role of the university in relevant software development education is considered with a specific focus on curricula. In the empirical study a questionnaire was developed to investigate the relevance of software development education from the perspective of the students. The questionnaire enquired about students’ interests in each of a list of software development topics and further questions relating to students’ views and needs for a relevant education are presented. The questionnaire was completed by 297 software development students and it was found that although a gap exists between students' needs and software development education, students’ education does have a predominantly social relevance and also a moderate personal and professional relevance. A second questionnaire was developed to investigate the relevance of software development education as it pertains to the software industry. The questionnaire enquired about the perceptions of professional software developers regarding what topics they learned from their formal education and the importance of these topics to their actual work. The questionnaire was completed by 214 software development professionals and again it was found that there is a gap between the industry’s needs and software development education. Questions related to the industry’s needs, as well as an open-ended question at the end of the questionnaire offered rich insights into the industry’s view of its new graduates and the problems and challenges surrounding software development education. The quantitative data, as well as the qualitative data offered solutions to these problems and challenges. The students’ views are compared with the professional software developers’ views to investigate the compatibility between the relevance of software development education for students and the relevance for the software industry. The analysis reveals matching and differing views. A framework for relevant software development education was developed to address the gap between software development education and the students’ needs, as well as the gap between software development education and the industry’s needs. The problems and challenges that might cause SD education to be less relevant are presented and recommendations to industry and university for relevant software development education are made. / PhD (Natural Sciences Education), North-West University, Potchefstroom Campus, 2015

It is widely acknowledged that there is a shortage of software developers with the right skills and knowledge. In respect of their university education, students want to take courses and carry out projects that clearly relate to their lives and their goals. The software development industry on the other hand, expects students to be educated in courses and projects, which are relevant for their professional career and equip them to be well-prepared for the workplace. In the middle, between the students and the industry, is the university that is expected to meet the needs of the students on the one side and the software industry on the other side. The unique contribution of this research is the development of a framework for relevant software development education by addressing the question: How can universities ensure that software development education provides knowledge and skill sets that are relevant to both the software development industry and software development students? The literature study investigates the software development class, focusing on the students and the educators. Furthermore, a review of the software development workplace is done with attention to the software developers and their employers. The problems and challenges facing three role players in software development education, namely the students, the university and the industry are investigated. Lastly, the role of the university in relevant software development education is considered with a specific focus on curricula. In the empirical study a questionnaire was developed to investigate the relevance of software development education from the perspective of the students. The questionnaire enquired about students’ interests in each of a list of software development topics and further questions relating to students’ views and needs for a relevant education are presented. The questionnaire was completed by 297 software development students and it was found that although a gap exists between students' needs and software development education, students’ education does have a predominantly social relevance and also a moderate personal and professional relevance. A second questionnaire was developed to investigate the relevance of software development education as it pertains to the software industry. The questionnaire enquired about the perceptions of professional software developers regarding what topics they learned from their formal education and the importance of these topics to their actual work. The questionnaire was completed by 214 software development professionals and again it was found that there is a gap between the industry’s needs and software development education. Questions related to the industry’s needs, as well as an open-ended question at the end of the questionnaire offered rich insights into the industry’s view of its new graduates and the problems and challenges surrounding software development education. The quantitative data, as well as the qualitative data offered solutions to these problems and challenges. The students’ views are compared with the professional software developers’ views to investigate the compatibility between the relevance of software development education for students and the relevance for the software industry. The analysis reveals matching and differing views. A framework for relevant software development education was developed to address the gap between software development education and the students’ needs, as well as the gap between software development education and the industry’s needs. The problems and challenges that might cause SD education to be less relevant are presented and recommendations to industry and university for relevant software development education are made. / PhD (Natural Sciences Education), North-West University, Potchefstroom Campus, 2015

No description available.

To demonstrate working exploits or vulnerabilities, people often share their findings as a form of proof-of-concept (PoC) prototype. Such practices are particularly useful to learn about real vulnerabilities and state-of-the-art exploitation techniques. Unfortunately, the shared PoC exploits are seldom reproducible; in part because they are often not thoroughly tested, but largely because authors lack a formal way to specify the tested environment or its dependencies. Although exploit writers attempt to overcome such problems by describing their dependencies or testing environments using comments, this informal way of sharing PoC exploits makes it hard for exploit authors to achieve the original goal of demonstration. More seriously, these non- or hard-to-reproduce PoC exploits have limited potential to be utilized for other useful research purposes such as penetration testing, or in benchmark suites to evaluate defense mechanisms. In this paper, we present XShop, a framework and infrastructure to describe environments and dependencies for exploits in a formal way, and to automatically resolve these constraints and construct an isolated environment for development, testing, and to share with the community. We show how XShop's flexible design enables new possibilities for utilizing these reproducible exploits in five practical use cases: as a security benchmark suite, in pen-testing, for large scale vulnerability analysis, as a shared development environment, and for regression testing. We design and implement such applications by extending the XShop framework and demonstrate its effectiveness with twelve real exploits against well-known bugs that include GHOST, Shellshock, and Heartbleed. We believe that the proposed practice not only brings immediate incentives to exploit authors but also has the potential to be grown as a community-wide knowledge base.

Most users find it difficult to remember traditional text-based passwords. In order to cope with multiple passwords, users tend to adopt unsafe mechanisms like writing down the passwords or sharing them with others. Recognition-based graphical authentication systems (RBGSs) have been proposed as one potential solution to minimize the above problems. But, most prior works in the field of RBGSs make the unrealistic assumption of studying a single password. It is also an untested assumption that RBGS passwords are resistant to being written down or verbally communicated. The main aim of the research reported in this thesis is to examine the memorability of multiple image passwords and their guessability using written descriptions (provided by the respective account holders). In this context, the thesis presents four user studies. The first user study (US1) examined the usability of multiple RBGS passwords with four different image types: Mikon, doodle, art and everyday objects (e.g. images of food, buildings, sports etc.). The results obtained in US1 demonstrated that subjects found it difficult to remember four RBGS passwords (of the same image type) and the memorability of the passwords deteriorated over time. The results of another usability study (US2) conducted using the same four image types (as in US1) demonstrated that the memorability of the multiple RBGS passwords created by employing a mnemonic strategy do not improve even when compared to the existing multiple password studies and US1. In the context of the guessability, a user study (GS1) examined the guessability of RBGS passwords (created in US1), using the textual descriptions given by the respective account holders. Another study (GS2) examined the guessability of RBGS passwords (created in US2), using descriptions given by the respective account holders. The results obtained from both the studies showed that RBGS passwords can be guessed using the password descriptions in the experimental set-up used. Additionally, this thesis presents a novel Passhint authentication system (PHAS).The results of a usability study (US3) demonstrated that the memorability of multiple PHAS passwords is better than in existing Graphical authentication systems (GASs). Although the registration time is high, authentication time for the successful attempts is either equivalent to or less than the time reported for previous GASs. The guessability study (GS3) showed that the art passwords are the least guessable, followed by Mikon, doodle and objects in that order. This thesis offers these initial studies as a proof of principle to conduct large scale field studies in the future with PHAS. Based on the review of the existing literature, this thesis identifies the need for a general set of principles to design usability experiments that would allow systematic evaluation and comparison of different authentication systems. From the empirical studies (US1, US2 and US3) reported in this thesis, we found that multiple RBGS passwords are difficult to remember, and the memorability of such passwords can be increased using the novel PHAS. We also recommend using the art images as the passwords in PHAS, because they are found to be the least guessable using the written descriptions in the empirical studies (GS1, GS2 and GS3) reported in this thesis.