Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-15T20:39:20Z No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T16:13:19Z (GMT) No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) / Made available in DSpace on 2017-05-17T16:13:19Z (GMT). No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) Previous issue date: 2012-09-05 / Estudos sobre saturação de espécies buscam conhecer o papel relativo de fatores locais e regionais sobre a estruturação das comunidades. No caso de comunidades zooplanctônicas, os resultados encontrados são bastante divergentes, tornando necessário o preenchimento de certas lacunas. Uma destas está na comparação entre diferentes tipos de ambiente, como perenes e temporários, que apresentam comunidades com características bem distintas. Lagoas temporárias passam periodicamente por eventos de seca e, considerando organismos aquáticos, este é um dos mais fortes distúrbios experimentados, pois impõe severas restrições fisiológicas e comportamentais. Baseado nestes fatos, este estudo tem como hipótese principal que lagoas temporárias apresentam comunidades zooplanctônicas insaturadas, enquanto lagoas perenes apresentam comunidades zooplanctônicas saturadas. Para testá-la, foi realizado um experimento em mesocosmos onde as comunidades zooplanctônicas destes dois tipos de lagoas foram manipuladas, bem como o evento de dispersão. Os resultados indicam que ambas apresentam-se saturadas e que, portanto, fatores locais são predominantemente mais importantes do que a dispersão (fator regional) sobre a estruturação destas comunidades. Dentre estes fatores locais, os fatores abióticos atuam como filtros selecionadores de espécies e parecem ser mais importantes do que as interações bióticas com as comunidades residentes. / Many studies about species saturation try to find out the relative role of the local and regional factors on the communities structure. Regarding to zooplankton communities, the results obtained are very divergent requiring the filling of certain gaps. One of these gaps is on the comparison between different types of environments, like perennial and temporary which have communities with very different features. Temporary ponds are periodically affected by drought events and, considering the aquatic organisms, this is one of the strongest disturbs that they experienced because it imposes physiological and behavioral restrictions. Based on these facts, the principal hypothesis of this study is that temporary ponds have unsaturated zooplankton communities while permanent ponds have saturated zooplankton communities. To test it, an experiment was made in mesocosms where the communities of both ponds were manipulated as well as the dispersion event. The results indicate that both communities are saturated and therefore local factors are predominantly more important than the dispersion (regional factor) on the structuring of these communities. Among these local factors, the abiotic factors act as species selectors filters and seems to be more relevant than the biotic interactions with the resident species.

Typically, systems biology focuses on the form and function of networks of biochemical interactions. Questions inevitably arise as to the evolutionary origin of those networks' properties. Such questions are of interest to a growing number of systems biologists, and several groups have published studies shown how varying environments can affect network topology and lead to increased evolvability. For decades, evolutionary biologists have also investigated the evolution of evolvability and its relationship to the interactions between genotype and phenotype. While the perspectives of systems and evolutionary biologists sometimes differ, their interests in patterns of interactions and evolvability have much in common. This thesis attempts to bring together the perspectives of systems and evolutionary theory to investigate the evolutionary effects of fluctuating environments. Chapter 1 introduces the necessary themes, terminology and literature from these fields. Chapter 2 explores how rapid environmental fluctuations, or "noise", affects network size and robustness. In Chapter 3, we use the Avida platform to investigate the relationship between genetic architecture, fluctuating environments and population biology. Chapter 4 examines contingency loci as a physical basis for evolvability, while chapter 5 presents a 500-generation laboratory evolution experiment which exposes E. coli to varying environments. The final discussion, concludes that the evolution of generalism can lead to genetic architectures which confer evolvability, which may arise in rapidly fluctuating environments as a by-product of generalism rather than as a selected trait.

A realização de videoconferências sem o uso de equipamentos que possuam tecnologia proprietária ou sem o uso de redes não comerciais (como a Internet 2) ou com características não comuns (como o protocolo Multicast) tem se revelado um desafio para os estudiosos do assunto. Este trabalho apresenta uma proposta de solução desse problema demonstrando que é possível estabelecer-se uma videoconferência entre muitas salas sobre a Internet 1, com qualidade de serviço, usando equipamentos comerciais comuns de informática e sem sobrecarga da rede. Para isso, por intermédio da integração de duas tecnologias grid (AccessGrid e Grid Delivery), são propostas as bases de uma nova versão de Access Grid, chamado MPAG (MultiPeer Access Grid). / The development of videoconferencing without the use of equipments with customized technology or without commercial networks (like Internet 2) or without common characteristics (as Multicast, for instance) has appeared as a challenge to the subject researchers. This work presents a proposal of solution to this problem, showing that is possible to create a videoconference between many rooms under the Internet 1, with quality of service, using common commercial computing equipments and without overloading the network. For this, two technologies of grid (AccessGrid and Grid Delivery) have been integrated, proposing the basis of a new version of Access Grid, called MPAG (MultiPeer Access Grid).

The management of online learning environments so that they are effective and efficient presents a significant challenge for institutions and lecturers due to the complexity of requirements in the learning and teaching domain. The use of 3D Multi User Virtual Environments (MUVEs) for education introduces a novel set of management challenges. MUVEs were designed to cater for entertainment and commercial needs and as such do not intrinsically support managed learning. When MUVEs are used for educational purposes, forming 3D Multi User Learning Environments (MULEs), user support for learning management becomes an important factor. This thesis highlights the importance of managed learning in MULEs. It proposes a coordinated approach which accommodates the existing education institutional infrastructure. The research has focused on two very widely used and closely compatible MUVEs, Second Life (SL) and OpenSim. The thesis presents system and user studies that have been carried out on these selected MUVEs. The findings reveal the challenges that academics and students can experience if they do not have sufficient knowhow to manage learning activities in SL/OpenSim. User guidance and training tools were then developed for supporting learning management strategies in the context of SL/OpenSim and demonstrated in exemplar use-case scenarios. The user support models and tools which were developed have been extensively evaluated for their usability and educational value using diverse participant groups. The results validate the efficacy of these contributions, defending the research thesis. These contributions can be used in future research on managing MUVE supported education.

This master thesis aims to critically analyze the state of digital libraries in Swedish academic libraries. With the branching theory of sense-making and the methodology of DELOS and IFLA/UNESCOs digital library manifestos, this thesis hopes to bring to light how far Swedish academic libraries have progressed. By accumulating quantitative data encompassing all digital academic libraries in Sweden, and qualitative data from a select few, conclusions regarding the aforementioned are drawn. Focusing on content analysis, this thesis analyzed the different components that can be said to constitute the digital library and compared them to the different manifestos that dictate what a digital library can be said to consist of. By employing the elusive sense-making theory as a general modus of mind, one can begin to understand thought-making processes behind the tapping of digital library resources. Results from this thesis found that some functions and components are present within all academic libraries in Sweden, but that the digital library primarily tends to focus on resource acquisition and not so much on resource presentation. User environments are not prioritized. Different aspects are presented in regards to mobile optimization, social media, information organization, information design etc. This is a two years master’s thesis in Archive, Library and Museum studies. / Den här masteruppsatsen syftar till att undersöka digitala bibliotek och digitala miljöer på svenska högskole- och universitetsbibliotek. Med sense-making som huvudsaklig teoretiskt ramverk och DELOS och IFLA/UNESCOs olika manifest gällande digitala bibliotek hoppas uppsatsen visa hur långt svenska bibliotek har kommit i relation till det digitala. Via samlandet av kvantitativ data från alla svenska akademiska bibliotek, och kvalitativ data från ett fåtal utvalda, kommer uppsatsen till diverse slutsatser. Med fokus på innehåll och funktion så undersöker uppsatsen vilka komponenter som kan sägas utgöra det digitala biblioteket i jämförelse med manifesten och deras ideala digitala bibliotek. Med hjälp av sense-making kan man få en förståelse för tankessättet och hur användare angriper de digitala resurserna. Resultaten från uppsatsen visade att det finns en viss grad av framsteg och utveckling som alla bibliotek har nått, men att den digitala satsningen oftast endast inbegriper samlandet av resurser och uppbyggandet av databaser snarare än presentation och design. Miljöer som gör att användarna frodas prioriteras ofta bort. Olika aspekter presenteras i relation till detta såsom mobil-optimering, sociala medier, informationsorganisation, informationsdesign osv. Det här är en tvåårig masteruppsats inom Arkiv, Bibliotek och museum.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Recently, there has been significant research focus on Peer-to-Peer (P2P) Massively Multi-user Virtual Environments (MMVEs). A number of architectures have been presented in the literature to implement the P2P approach. One aspect that has not received sufficient attention in these architectures is state management and state persistency in P2P MMVEs. This work presents and simulates a novel state management and persistency architecture, called Pithos. In order to design the architecture, an investigation is performed into state consistency architectures, into which the state management and persistency architecture should fit. A novel generic state consistency model is proposed that encapsulated all state consistency models reviewed. The requirements for state management and persistency architectures, identified during the review of state consistency models, are used to review state management and persistency architectures currently receiving research attention. Identifying some deficiencies present in current designs, such as lack of fairness, responsiveness and scalability, a novel state management and persistency architecture, called Pithos, is designed. Pithos is a reliable, responsive, secure, fair and scalable distributed storage system, ideally suited to P2P MMVEs. Pithos is implemented in Oversim, which runs on the Omnet++ network simulator. An evaluation of Pithos is performed to verify that it satisfies the identified requirements. It is found that the reliability of Pithos depends heavily on object lifetimes. If an object lives longer on average, retrieval requests are more reliable. An investigation is performed into the factors influencing object lifetime. A novel Markov chain model is proposed which allows for the prediction of objects lifetimes in any finite sized network, for a given amount of redundancy, node lifetime characteristics and object repair rate. / AFRIKAANSE OPSOMMING: Onlangs is daar ’n beduidende navorsingsfokus op Eweknie Massiewe Multi-gebruiker Virtuele Omgewings (MMVOs). ’n Aantal argitekture is in die literatuur beskikbaar wat die eweknie benadering voorstel. Een aspek wat nie voldoende aandag ontvang in hierdie argitekture nie is toestandsbestuur en toestandsvolharding in eweknie MMVOs. Hierdie werk ontwerp en simuleer ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur genaamd Pithos. Ten einde die argitektuur te ontwerp is ’n ondersoek uitgevoer in toestandskonsekwentheidargitekture, waarin die toestandsbestuur- en toestandsvolhardingargitektuur moet pas. ’n Nuwe generiese toestandskonsekwentheidargitektuur word voorgestel wat alle hersiene toestandskonsekwentheid argitekture vervat. Die vereistes vir die toestandsbestuur- en toestandsvolhardingargitekture, geidentifiseer tydens die hersiening van die toestandskonsekwentheidargitekture, word gebruik om toestandsbestuuren toestandsvolhardingargitekture te hersien wat tans navorsingsaandag geniet. Identifisering van sekere leemtes teenwoordig in die huidige ontwerpe, soos ’n gebrek aan regverdigheid, responsiwiteit en skaleerbaarheid, lei tot die ontwerp van ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur wat Pithos genoem word. Pithos is ’n betroubare, responsiewe, veilige, regverdige en skaleerbare verspreide stoorstelsel, ideaal geskik is vir eweknie MMVOs. Pithos word geïmplementeer in Oversim, wat loop op die Omnet++ netwerk simulator. ’n Evaluering van Pithos word uitgevoer om te verifieer dat dit voldoen aan die geïdentifiseerde behoeftes. Daar is gevind dat die betroubaarheid van Pithos afhang van die objek leeftyd. As ’n objek gemiddeld langer leef, dan is herwinning versoeke meer betroubaar. ’n Ondersoek word uitgevoer na die faktore wat die objek leeftyd beïnvloed. ’n Nuwe Markov ketting model word voorgestel wat voorsiening maak vir die voorspelling van objek leeftye in eindige grootte netwerke, vir gegewe hoeveelhede van oortolligheid, nodus leeftyd eienskappe en objek herstelkoers.

<p>Software engineering tools are being used in the industry in order to improve the productivity and the quality of the software development process. The properties of those tools are being perceived to be unsatisfactory. For example, researchers have found that some problems are due to deficient integration among the tools. Furthermore, a continuing problem is that there is a gap between the IT education and real demand of tool-skills form IT industry. Consequently, knowledge is needed of the properties of software development tools as well an understanding of demanded tool-skill from the industry. </p><p>The purpose of this study is to survey commercial software development environment (SDEs) that are used today in professional software engineering and discuss their advantages adn disadvantages. A secondary goal of the study is to identify the actual requirements from the industry on the IT-education. </p><p>A questionnaire was sent out to 90 software developers and IT managers of 30 IT companies in Sweden. The results of the survey show that IT companies, for most part, use SDEs from commercial software vendors. Respondents report that common problems of the SDEs are the following: bad integration among the tools, problems to trace software artifacts in the different phases of the programming cycle, and deficient support for version control and system configuration. Furthermore, some tools are difficult to use which results in a time-consuming development process. </p><p>We conclude that future software development environments need to provide better support for integration, automation, and configuration management. Regarding the required tool-skills, we believe that the IT education would gain from including commercial tools that cover the whole software product lifecycle in the curriculum.</p>

Many types of multi-display environments (MDEs) are emerging that allow users to better interact with computers. In these environments, being able to move visual objects (such as window icons or the cursor) from one display to another is a fundamental activity. This dissertation focuses on understanding how human performance of cross-display actions is affected by the design of cross-display object movement interaction techniques. Three main aspects of cross-display actions are studied: how displays are referred to by the system and the users, how spatial actions are planned, and how actions are executed. Each of these three aspects is analyzed through laboratory experiments that provide empirical evidence on how different characteristics of interaction techniques affect performance. The results further our understanding of cross-display interaction and can be used by designers of new MDEs to create more efficient multi-display interfaces.

This report begins with the presentation of &amp;quot;the state of the art&amp;quot; as well as the foreseen trend in the education system in Mozambique and analyses the present situation in the area utilizing media opportunities for teaching and/or learning. Basing on this analysis, the prevailing problems and the aims (this might need research) of the study shall then be identified and formulated (chapter 1 and 2). The necessity to carry out the study is grounded by the worldwide stormy developments utilizing modern information technology. These developments do also apply to Mozambique as the pre-studies show. A flashback on the history of teaching-/learning system as well as on present solutions utilizing new media and new information as well as communication technology shall be discussed in the third chapter. To this end, the study shall contribute to identify the lacking of previous concepts as well as to introduce an orientation as to the current world sustainable system. The software for training on the market at present show (without doubt) that they reflect developers' imaginations (knowingly or unknowingly) as to what learning and teaching actually is and how this process take place. Basing on this knowledge, it is worth to work out the starting point as to teaching-/learning methodology before working out a conception. In addition, it shall be made clear (in the course of analysis) that the dominating criterion for customizing a teaching-/learning system is that system or its form that has been realised. The contribution of this report, further, is to make the definition of the media more precise by adding new terminology that shall be discussed and viewed from different viewpoints. This shall in turn contribute to a clear and sound understanding of the media. In the past years, a series of different teaching and methodologies concepts on the design of computer-based teaching-/learning environment were developed and discussed. Among them is the so called &amp;quot;anchored instruction&amp;quot; of the cognition and Technology Group based at Vanderbilt University and the Cognitive Apprenticeship developed by Collins, Brown and their co-workers. This shall be dealt with in the fourth chapter. On that basis, and taking other factors into consideration, such as design, functionality, applications scenarios, boundary conditions as well as user backgrounds, a more effective teaching-/learning environment can be predicted and consequently a concrete design proposal can be derived. The guidelines strived as to the design of context-sensitive multimedia teaching and learning environment shall not only be treated intuitive, but implemented technically in a prototype. In so doing they can then be evaluated and adopted. The so evaluated guidelines and other relevant design proposals that can find use in other areas with respect to the demand of the study as a whole shall make the results of this report. The fifth chapter shall describe the development and evaluation of prototype-art &amp;quot;e-Aula&amp;quot; solutions basing on the developed and grounded conception. The conception constitutes of a hybrid solution in the form of training software that supports both freelance as well as classroom learning. This training technology solution is called teaching-/learning environment and it is being characterised through its feature that it embodies two system interfaces having functions (learning environment and teaching arrangement) that basically refer to the same data collection (media) that can be accessed by the in different ways. This function rates &amp;quot;e-Aula&amp;quot; at a relatively higher position in comparison with a number of learning systems. The sixth chapter shall then summarise the important findings of the report and recommend areas for further research. Appendix: e-Aula Suite 1.0 (1,26 MB) Usage: Referat Informationsvermittlung der SLUB / Mit der Arbeit wurde Ein Konzept für eine Hybridlösung in Form von Bildungssoftware entwickelt begründet und evaluiert, mit der sich einmal erzeugte digitale didaktische Medien sowohl für selbstständiges und unterrichtliches Lernen in sog. &amp;quot;Multimedia Learning Environments&amp;quot; als auch für das Lehren über sog. &amp;quot;Teaching Arrangements&amp;quot; nutzen lassen. Anlage: e-Aula Suite 1.0 (1,26 MB) Nutzung: Referat Informationsvermittlung der SLUB

Recently, several SiGe HBT devices fabricated on CMOS-compatible silicon on insulator (SOI) substrates (SiGe HBTs-on-SOI) have been demonstrated, combining the well-known SiGe HBT performance with the advantages of SOI substrates. These new devices are especially interesting in the context of extreme environments - highly challenging surroundings that lie outside commercial and even military electronics specifications. However, fabricating HBTs on SOI substrates instead of traditional silicon bulk substrates requires extensive modifications to the structure of the transistors and results in significant trade-offs. The present work investigates, with measurements and TCAD simulations, the performance and reliability of SiGe heterojunction bipolar transistors fabricated on silicon on insulator substrates with respect to operation in extreme environments such as at extremely low or extremely high temperatures or in the presence of radiation (both in terms of total ionizing dose and single effect upset).