The workshop ¨Portierbare numerische Simulationen auf parallelen Architekturen¨ (¨Portable numerical simulations on parallel architectures¨) was organized by the Fac- ulty of Informatics/Professorship Computer Architecture at 18 April 1996 and held in the framework of the Sonderforschungsbereich (Joint Research Initiative) ¨Numerische Simulationen auf massiv parallelen Rechnern¨ (SFB 393) (¨Numerical simulations on massiv parallel computers¨) ( http://www.tu-chemnitz.de/~pester/sfb/sfb393.html ) The SFB 393 is funded by the German National Science Foundation (DFG). The purpose of the workshop was to bring together scientists using parallel computing to provide integrated discussions on portability issues, requirements and future devel- opments in implementing parallel software efficiently as well as portable on Clusters of Symmetric Multiprocessorsystems. I hope that the present paper gives the reader some helpful hints for further discussions in this field.

Numerous studies have concluded that roughly half of all implemented software requirements are never or rarely used in practice, and that failure to realise expected benefits is a major cause of software project failure. This thesis presents an exploration of these concepts, claims, and causes. It evaluates the literature s proposed solutions to them, and then presents a unified framework that covers additional concerns not previously considered. The value of a requirement is assessed often during the requirements engineering (RE) process, e.g., in requirement prioritisation, release planning, and trade-off analysis. In order to support these activities, and hence to support the decisions that lead to the aforementioned waste, this thesis proposes a framework built on the modelling languages of Goal Oriented Requirements Engineering (GORE), and on the principles of Value Based Software Engineering (VBSE). The framework guides the elicitation of a requirement s value using philosophy and business theory, and aims to quantitatively model chains of instrumental value that are expected to be generated for a system s stakeholders by a proposed software capability. The framework enriches the description of the individual links comprising these chains with descriptions of probabilistic degrees of causation, non-linear dose-response and utility functions, and credibility and confidence. A software tool to support the framework s implementation is presented, employing novel features such as automated visualisation, and information retrieval and machine learning (recommendation system) techniques. These software capabilities provide more than just usability improvements to the framework. For example, they enable visual comprehension of the implications of what-if? questions, and enable re-use of previous models in order to suggest modifications to a project s requirements set, and reduce uncertainty in its value propositions. Two case studies in real-world industry contexts are presented, which explore the problem and the viability of the proposed framework for alleviating it. The thesis research questions are answered by various methods, including practitioner surveys, interviews, expert opinion, real-world examples and proofs of concept, as well as less-common methods such as natural language processing analysis of real requirements specifications (e.g., using TF-IDF to measure the proportion of software requirement traceability links that do not describe the requirement s value or problem-to-be-solved). The thesis found that in general, there is a disconnect between the state of best practice as proposed by the literature, and current industry practice in requirements engineering. The surveyed practitioners supported the notion that the aforementioned value realisation problems do exist in current practice, that they would be treatable by better requirements engineering practice, and that this thesis proposed framework would be useful and usable in projects whose complexity warrants the overhead of requirements modelling (e.g., for projects with many stakeholders, competing desires, or having high costs of deploying incorrect increments of software functionality).

This paper addresses two different aspects of the subject known as knowledge bases, or knowledge graphs. A knowledge base is defined as a comprehensive semantically organized machine-readable collection of universally relevant or domain-specific entities, classes, and facts. The objective of this paper is to explore how a knowledge base can be used to gain information about an entity. First we present one way to access information from the knowledge base using a back-end interface. This back-end interface takes simple parameters as input which are used to query the knowledge base. The main objective here is to be able to access the right entity, to be able to answers the questions correctly.  After that follows a discussion about the need for knowledge bases and possible uses. The discussions will partly be based on results from our implementation, but also consider other similar implementation, and interviews with possible users in the business and society.  We conclude that the back-end interface developed performs well enough, with a high precision, to be ran in an unsupervised system. Furthermore we realise that the interface can be improved in several ways by focusing on smaller domains of information. Several different possible uses have been identified. From these uses a market analysis has been done from which we conclude good market possibilities. Some of the key problems with implementing the interface regards the credibility of the information in the knowledge base. This is one of the main problems that needs to be solved to fully implement knowledge bases in business and society. / Den här rapporten tar upp två olika områden som berör knowledge bases. En knowledge base definieras som en omfattande semantiskt organiserad maskinläslig samling av universellt relevanta eller domän-specifika entiteter, klasser, och fakta. Målet med rapporten är att undersöka hur en knowledge base kan användas för att få fram information om en entitet. Först presenteras ett tillvägagångsätt för kommunikation mot en knowledge base med hjälp av ett back-end gränssnitt. Back-end gränssnittet tar enkla parametrar som input och använder dessa för att köra en query mot en knowledge base. Huvudfokus i denna del kommer ligga i att få rätt svar på frågorna och kommer därmed att utvärderas utifrån det. Det andra området som arbetet berör är en diskussion kring hur knowledge bases kan integreras i samhället och näringslivet för att få ut en ökad nytta. Diskussionerna kommer att baseras på resultaten från den första delen av arbetet till viss del, men även andra liknande studier kommer vägas in för att ge ett bredare diskussionsunderlag. Utöver detta baseras också diskussionen på intervjuer med möjliga intressenter inom näringsliv och samhälle. Det utvecklade gränssnittet presterar på en nivå, med hög precision, som vi bedömer tillräcklig för implementering i oövervakade system. Dessutom har flertalet förbättringsområden identifierats. Huvudsakligen berör dessa att mer specifika implementationer kan få högre precision då specifikare kontroller kan genomföras. Flertal möjliga användningsområden har identifierats. Med dessa som grund har en marknadsanalys genomförts som pekar på goda förutsättningar för tekniken. Ett av det största problemen berör trovärdigheten i informationen i knowledge basen. Det är ett problem som måste lösas innan tekniken kan implementeras fullt ut i näringsliv och samhälle.

The global urban population is projected to grow rapidly in the coming years, leading to an increase in housing demand that is not always met with adequate supply of quality housing. In the low-and middle-income context of Kenya, this gap has led to the proliferation of sub-standard housing implementations, with significant social and environmental impacts. However, attention is rarely paid to sustainable housing design practices in Kenya, understood here as climate responsive and socially integrated adaptations, despite their proven capacity in other developing countries for reducing environmental impacts while making housing more affordable. The city of Nairobi presents potential for alternative trajectories of development in the construction industry as one of the fastest growing urban areas in the region with unique climatic conditions that are underutilised and understudied in the building sector. This thesis explores, through the perspectives of local actors, the potentials and challenges of implementing affordable housing in Nairobi by using sustainable, locally based strategies. This was achieved through desktop research, semi-structured interviews with key actors from across government, academia, and industry backgrounds, as well as a field visit to a development site. The collected data was then analysed qualitatively through a thematic content analysis and triangulated to extract relevant learnings. The key findings of this research are that there is a lot of potential in Nairobi for locally adapted housing strategies to respond to affordable housing issues and provide low-cost and high-quality alternatives due to its climatic conditions and socio-cultural traditions. Yet there are some structural challenges in terms of policy framing and local perceptions of sustainability that limit the implementation of such practices in the Nairobi housing sector. This thesis adds to the critical discussion of adequate affordable housing by providing a holistic view of the differing or overlapping perspectives in the field, deriving potentials of the local context, and providing an understanding that could help guide the housing industry in the direction of resilient and inclusive housing opportunities. The study suggests the need for further research into the implementation of sustainable and affordable housing in the context of Nairobi, as well as the wider regional context. / Den globala stadsbefolkningen förväntas växa snabbt under de kommande åren, vilket leder till en ökad efterfrågan på bostäder som inte alltid möts av ett tillräckligt utbud av kvalitetsbostäder. Bland Kenyas låg- och medelinkomsttagare, har denna klyfta mellan efterfrågan och utbud av bostäder lett till att informella bosättningar och bostäder av undermålig kvalitet har blivit allt vanligare. Detta har en betydande inverkan på miljön, men ändå ägnas sällan uppmärksamhet åt hållbara bostadsmetoder i Kenya, trots att de har visat sig kunna minska miljöpåverkan i andra utvecklingsländer samtidigt som de löser problem med överkomliga priser. Staden Nairobi har potential för alternativ utveckling inom byggbranschen, eftersom denär ett av de snabbast växande stadsområdena i regionen, en viktig knutpunkt för handel, transport, kommunikation och innovation, och har unika klimatförhållanden som är underutnyttjade och understuderade inom byggsektorn. Mer lokalt anpassade bioklimatiska och klimatsmarta byggnadsstrategier kan spela en grundläggande roll när det gäller att tillgodose efterfrågan på lämpliga bostäder till överkomliga priser i Kenya, bland annat genom att anpassa de byggda formerna till det lokala sammanhanget. I den här artikeln undersöks möjligheterna och utmaningarna med att skapa överkomliga priser i Nairobi med hjälp av hållbara, lokalt förankrade strategier, från perspektivet av lokala nyckelaktörer inom byggbranschen. Detta uppnåddes genom skrivbordsforskning, semistrukturerade intervjuer och ett fältbesök på en byggarbetsplats, vars uppgifter sedan triangulerades för att få fram relevanta uppgifter. De viktigaste resultaten av denna forskning är att det finns en stor potential i Nairobi för lokalt anpassade bostadsstrategier att lösa problemen med bostäder till överkomliga priser och tillhandahålla billiga och högkvalitativa alternativ givet klimatförhållandena och de sociokulturella traditionerna. Det finns dock vissa strukturella utmaningar som begränsar genomförandet av sådana lösningar och som måste åtgärdas för att de ska bli relevanta och motståndskraftiga inom bostadssektorn i Nairobi. Denna avhandling bidrar till litteraturen genom att ge en helhetsbild av de olika eller överlappande perspektiven på området, genom att härleda potentialer från den lokala kontexten och genom att ge en förståelse som förhoppningsvis kommer att hjälpa vägleda bostadsbranschen i riktning mot motståndskraftiga och inkluderande bostadsmöjligheter. Den ämnar även att bjuda in till ytterligare forskning om genomförandet av hållbara och prisvärda bostäder i Nairobi och i ett bredare regionalt sammanhang, samt uppmanar till ett nytt sätt att betrakta stadsutvecklingen, trots de problem som finns när det gäller att genomföra den på ett hållbart sätt.

The purpose of this qualitative case study is threefold: (1) to examine the implementation of current Life Sciences curriculum in a selected primary school from the perspectives of teachers, students and administrators / (2) to investigate the degree to which teachers&rsquo / , students&rsquo / and administrators&rsquo / perceptions were embedded in the classroom practices / and (3) to identify whether the implementation of the curriculum was conducive to principles of constructivist pedagogy. An elementary school was chosen as a single case in an outer district of Ankara. The participants of the study were the school administrator and 2 co-administrators, 4 classroom teachers and 87 students from different 2nd and 3rd grades classrooms. The data were collected through document analysis, observations in the Life Sciences classes, semi-structured interview with administrators, stimulated recall interview with teachers, and creative drama with students. Content analysis was used to analyze the data. The findings indicated that the suggested Life Sciences Curriculum was conducive to the principles of constructivist pedagogy in terms of its content / teaching and learning processes / instructional methods / assessment methods / and teachers&rsquo / and students&rsquo / roles. However, the acquisitions of the LSC were not conducive to the constructivist approach. The findings on the teachers&rsquo / , students&rsquo / and administrators&rsquo / perceptions about the Life Sciences curriculum indicated that in Life Sciences lessons the teachers seemed to have a role of knowledge transmitter to a group of passive students. According to the findings, the most frequently used teaching methods were lecturing, question-answer and demonstration through using textbooks, workbooks, and white boards. In addition, the most frequently used assessment methods were essay and oral exams, classroom observations and self-assessment. Overall it can be concluded from the findings that although the suggested Life Sciences curriculum was prepared in line with the principles of constructivist pedagogy, the way it was implemented had some deficiencies regarding the actualization of goals suggested by a constructivist curriculum.

No description available.

Made available in DSpace on 2016-03-22T17:26:43Z (GMT). No. of bitstreams: 1 gustavo.pdf: 2041277 bytes, checksum: 42156e7b6b140c8fd9dcda43abcba411 (MD5) Previous issue date: 2010-09-11 / The recent advances in computer technology have increased the use of computer clusters for running applications which require a large computational effort, making this practice a strong tendency. Following this tendency, the D-GM (Geometric Distributed- Machine) environment is a tool, composed by two software modules, VPE-GM (Visual Programming Environment for Geometric Machine) and VirD-GM (Virtual Distributed Geometric Machine), whose goals are the development of applications of the scientific computation applying visual programming and parallel and/or distributed execution, respectively. The core of the D-GM environment is based on the Geometric Machine (GM Model), which is an abstract machine model for parallel and/or concurrent computations, whose definitions cover the existing parallels to process executions. The main contribution of this work is the formalization and development of a distributed memory for the D-GM environment, designing, modeling and constructing the integration between such environment and a distributed shared memory (DSM) system. Therefore, it aims at obtaining a better execution dynamic with major functionality and possibly, an increase in performance in the D-GM execution applications. This integration, whose objective is to supply a shared distributed memory module to the D-GM environment, is called ShareD-GM environment. Based on the study of DSM softwares implementations, mainly on their characteristics which meet all the requirements to implement the distributed memory of the D-GM environment, this work considers the use of Terracotta system. This study highlights two facilities both present in Terracota: the portability and adaptability for distributed execution in a cluster of computers with no code modifications (codeless clustering). Besides these characteristics, one can observe that Terracotta does not make use of RMI (Remote Method Invocation) for communication among objects in a JAVA environment. From this point of view, one may also minimize the overhead of data serializations (marshalling) in network transmissions. In addition, the development of applications to evaluate the implementation of the architecture model provided by the ShareD-GM integration, as the algorithm Smith-Waterman and the Jacobi method, showed a shorter running time when compared to the previous VirD-GM execution module / O recente avanc¸o das tecnologias de computadores impulsionaram o uso de clusters de computadores para execuc¸ ao de aplicac¸ oes que exijam um grande esforc¸o computacional, tornando esta pr´atica uma forte tend encia atual. Acompanhando esta tend encia, o Ambiente D-GM (Distributed-Geometric Machine) constitui-se em uma ferramenta compreendendo dois m´odulos de software, VPE-GM (Visual Programming Environment for Geometric Machine) e VirD-GM (Virtual Distributed Geometric Machine), os quais objetivam o desenvolvimento de aplicac¸ oes da computac¸ ao cient´ıfica aplicando a programac¸ ao visual e a execuc¸ ao paralela e/ou distribu´ıda, respectivamente. O n´ucleo do Ambiente D-GM est´a fundamentado na M´aquina Geom´etrica (Geometric Machine-GM), um modelo de m´aquina abstrato para computac¸ oes paralelas e/ou concorrentes cujas definic¸ oes abrangem os paralelismos existentes para execuc¸ ao de processos. A principal contribuic¸ ao deste trabalho ´e a formalizac¸ ao e desenvolvimento de uma mem´oria distribu´ıda para o Ambiente D-GM atrav´es da concepc¸ ao, modelagem e construc¸ ao da integrac¸ ao entre o Ambiente D-GM e um sistema DSM (Distributes Shared Memory). Portanto, visando melhoria na din amica de execuc¸ ao com maior funcionalidade e, possivelmente, com melhor desempenho no ambiente D-GM. A esta integrac¸ ao, cujo objetivo ´e fornecer um modelo de mem´oria compartilhada distribu´ıda para o Ambiente D-GM, d´a-se o nome de ShareD-GM. Com base no estudo de implementac¸ oes em software de DSM e nas caracter´ısticas que atendem aos requisitos de implementac¸ ao da mem´oria distribu´ıda do Ambiente D-GM, este trabalho considera o uso do sistema Terracotta. Salientam-se duas facilidades apresentadas pelo Terracota: a portabilidade e a adaptabilidade para execuc¸ ao distribu´ıda em clusters de computadores com pouca ou at´e nenhuma modificac¸ ao no c´odigo (codeless clustering), as quais retornam grandes benef´ıcios quando da integrac¸ ao com aplicac¸ oes JAVA. Al´em disso, verifica-se o fato de que o Terracotta n ao utiliza RMI (Remote Method Invocation) para comunicac¸ ao entre os objetos em um Ambiente JAVA. Neste perspectiva, procura-se minimizar o overhead dos dados produzidos pelas serializac¸ oes (marshalling) nas transmiss oes via rede. P ode-se tamb´em comprovar durante o desenvolvimento de testes de avaliac¸ ao da implementac¸ ao da arquitetura proporcionada pela integrac¸ ao ShareD-GM, que a execuc¸ ao de aplicac¸ oes modeladas no Ambiente D-GM, como o algoritmo de Smith-Waterman e o m´etodo de Jacobi, apresentaram menor tempo de execuc¸ ao quando comparados com a implementac¸ ao anterior, no m´odulo VirD-GM de execuc¸ ao do Ambiente D-GM

Side-Channel Analysis plays an important role in cryptology, as it represents an important class of attacks against cryptographic implementations, especially in the context of embedded systems such as hand-held mobile devices, smart cards, RFID tags, etc. These types of attacks bypass any intrinsic mathematical security of the cryptographic algorithm or protocol by exploiting observable side-effects of the execution of the cryptographic operation that may exhibit some relationship with the internal (secret) parameters in the device. Two of the main types of side-channel attacks are timing attacks or timing analysis, where the relationship between the execution time and secret parameters is exploited; and power analysis, which exploits the relationship between power consumption and the operations being executed by a processor as well as the data that these operations work with. For power analysis, two main types have been proposed: simple power analysis (SPA) which relies on direct observation on a single measurement, and differential power analysis (DPA), which uses multiple measurements combined with statistical processing to extract information from the small variations in power consumption correlated to the data. In this thesis, we propose several countermeasures to these types of attacks, with the main themes being timing analysis and SPA. In addition to these themes, one of our contributions expands upon the ideas behind SPA to present a constructive use of these techniques in the context of embedded systems debugging. In our first contribution, we present a countermeasure against timing attacks where an optimized form of idle-wait is proposed with the goal of making the observable decryption time constant for most operations while maintaining the overhead to a minimum. We show that not only we reduce the overhead in terms of execution speed, but also the computational cost of the countermeasure, which represents a considerable advantage in the context of devices relying on battery power, where reduced computations translates into lower power consumption and thus increased battery life. This is indeed one of the important themes for all of the contributions related to countermeasures to side- channel attacks. Our second and third contributions focus on power analysis; specifically, SPA. We address the issue of straightforward implementations of binary exponentiation algorithms (or scalar multiplication, in the context of elliptic curve cryptography) making a cryptographic system vulnerable to SPA. Solutions previously proposed introduce a considerable performance penalty. We propose a new method, namely Square-and-Buffered- Multiplications (SABM), that implements an SPA-resistant binary exponentiation exhibiting optimal execution time at the cost of a small amount of storage --- O(\sqrt(\ell)), where \ell is the bit length of the exponent. The technique is optimal in the sense that it adds SPA-resistance to an underlying binary exponentiation algorithm while introducing zero computational overhead. We then present several new SPA-resistant algorithms that result from a novel way of combining the SABM method with an alternative binary exponentiation algorithm where the exponent is split in two halves for simultaneous processing, showing that by combining the two techniques, we can make use of signed-digit representations of the exponent to further improve performance while maintaining SPA-resistance. We also discuss the possibility of our method being implemented in a way that a certain level of resistance against DPA may be obtained. In a related contribution, we extend these ideas used in SPA and propose a technique to non-intrusively monitor a device and trace program execution, with the intended application of assisting in the difficult task of debugging embedded systems at deployment or production stage, when standard debugging tools or auxiliary components to facilitate debugging are no longer enabled in the device. One of the important highlights of this contribution is the fact that the system works on a standard PC, capturing the power traces through the recording input of the sound card.

Side-Channel Analysis plays an important role in cryptology, as it represents an important class of attacks against cryptographic implementations, especially in the context of embedded systems such as hand-held mobile devices, smart cards, RFID tags, etc. These types of attacks bypass any intrinsic mathematical security of the cryptographic algorithm or protocol by exploiting observable side-effects of the execution of the cryptographic operation that may exhibit some relationship with the internal (secret) parameters in the device. Two of the main types of side-channel attacks are timing attacks or timing analysis, where the relationship between the execution time and secret parameters is exploited; and power analysis, which exploits the relationship between power consumption and the operations being executed by a processor as well as the data that these operations work with. For power analysis, two main types have been proposed: simple power analysis (SPA) which relies on direct observation on a single measurement, and differential power analysis (DPA), which uses multiple measurements combined with statistical processing to extract information from the small variations in power consumption correlated to the data. In this thesis, we propose several countermeasures to these types of attacks, with the main themes being timing analysis and SPA. In addition to these themes, one of our contributions expands upon the ideas behind SPA to present a constructive use of these techniques in the context of embedded systems debugging. In our first contribution, we present a countermeasure against timing attacks where an optimized form of idle-wait is proposed with the goal of making the observable decryption time constant for most operations while maintaining the overhead to a minimum. We show that not only we reduce the overhead in terms of execution speed, but also the computational cost of the countermeasure, which represents a considerable advantage in the context of devices relying on battery power, where reduced computations translates into lower power consumption and thus increased battery life. This is indeed one of the important themes for all of the contributions related to countermeasures to side- channel attacks. Our second and third contributions focus on power analysis; specifically, SPA. We address the issue of straightforward implementations of binary exponentiation algorithms (or scalar multiplication, in the context of elliptic curve cryptography) making a cryptographic system vulnerable to SPA. Solutions previously proposed introduce a considerable performance penalty. We propose a new method, namely Square-and-Buffered- Multiplications (SABM), that implements an SPA-resistant binary exponentiation exhibiting optimal execution time at the cost of a small amount of storage --- O(\sqrt(\ell)), where \ell is the bit length of the exponent. The technique is optimal in the sense that it adds SPA-resistance to an underlying binary exponentiation algorithm while introducing zero computational overhead. We then present several new SPA-resistant algorithms that result from a novel way of combining the SABM method with an alternative binary exponentiation algorithm where the exponent is split in two halves for simultaneous processing, showing that by combining the two techniques, we can make use of signed-digit representations of the exponent to further improve performance while maintaining SPA-resistance. We also discuss the possibility of our method being implemented in a way that a certain level of resistance against DPA may be obtained. In a related contribution, we extend these ideas used in SPA and propose a technique to non-intrusively monitor a device and trace program execution, with the intended application of assisting in the difficult task of debugging embedded systems at deployment or production stage, when standard debugging tools or auxiliary components to facilitate debugging are no longer enabled in the device. One of the important highlights of this contribution is the fact that the system works on a standard PC, capturing the power traces through the recording input of the sound card.

This thesis analyzes the projects&rsquo / implementations of EskiSehir Greater Municipality in European City context. In this thesis, Regional and Urban Policies of European Union and their historical bases are discussed, moreover / projects of EskiSehir Greater Municipality are examined in accordance with these theoretic parts and with principles of a European City. The thesis also seeks to answer the questions such as why Turkish cities have an aim to be a European City and what should be accomplished to satisfy the conditions of European City.