Brennstoffzellen-Stapel werden zu Beginn ihres Bauteil-Lebens einmal abschließend fix verspannt. Für das Kompressionsverhalten der Einheitszelle ist das Material der Bipolarplatte eine maßgebliche Einflussgröße. Auf Ebene der Bipolarplatte werden allgemein zwei Basismaterialien verwendet; beschichtete Metallplatten und Carbonplatten. Metallische Bipolarplatten bestehen aus dünnen Blechen. Bipolarplatten aus Carbon sind Vollkörper-Elemente aus carbongraphitischem Kompositmaterial, in deren Vollkörper die geometrische Struktur des Plattendesigns eingebettet ist. In diesem Beitrag wird ein Vergleich zwischen der Verpressung von Metallplatten-Stapeln gegenüber Carbonplatten-Stapeln auf Basis von produktionsnahen, statistischen Daten herangezogen. Hierbei ist das jeweils unterschiedliche Kompressionverhalten der Brennstoffzellen-Stapel mit ihren entsprechenden Federelementen entscheidend. Der Vergleich zeigt, dass ein fundamentaler Unterschied im Kompressionsverhalten zwischen beschichteten Metallplatten und komposit-basierten Carbonplatten besteht. Dies ist insbesondere im Hinblick auf großserien-taugliche Produktionsverfahren entscheidend, bei dem eng getaktete Stapel- und Verspannprozesse eine Schlüsselstelle im Aufbau von Brennstoffzellen-Stapeln als Massenprodukt darstellen. / Fuel cell stacks are finally clamped in place at the beginning of their component life. The material of the bipolar plate is a decisive influencing factor for the compression behavior of the unit cell. Two basic materials are generally used at the level of the bipolar plate; coated metal plates and carbon plates. Metallic bipolar plates consist of thin sheets. Bipolar plates made of carbon are full-body elements made of carbon-graphitic composite material, in whose full body the geometric structure of the plate design is embedded. This article uses a comparison between the compression of metal plate stacks versus carbon plate stacks on the basis of production-related statistical data. The different compression behavior of the fuel cell stacks with their corresponding spring elements is decisive here. The comparison shows that there is a fundamental difference in the compression behavior between coated metal plates and composite-based carbon plates. This is particularly important with regard to production processes suitable for large-scale series, in which closely-timed stacking and clamping processes represent a key point in the construction of fuel cell stacks as a mass product.

Le développement de la technologie « piles à combustible » nécessite l'utilisation d'outils de diagnostic adéquats notamment pour le monitoring de l'état de santé des systèmes industriels (stacks) dans les conditions réelles de fonctionnement. L'utilisation des moyens traditionnels de diagnostic nécessite l'arrêt ou la perturbation du fonctionnement du système. Le travail de cette thèse vise le développement d'une approche innovante non intrusive pour le diagnostic des stacks PEM (Proton Exchange Membrane), basée sur la mesure des petites fluctuations électriques (bruits électrochimiques). Pour mesurer les bruits, un système d'acquisition des faibles signaux à haute fréquence a été utilisé sans filtrage analogique préalable. Ces mesures ont été dans le cadre du projet ANR « Propice » pour quatre campagnes de mesures avec la collaboration du FCLAB et du CEA LITEN. Les mesures des bruits électrochimiques, sur plusieurs semaines, ont permis de construire une base de données extrêmement riche. Pour traiter ces données, différents approches statistiques dans le domaine temporel, fréquentiel et tempo-fréquentiel ont été utilisés pour la génération de descripteurs fiables et robustes. Il a été démontré que la mesure des bruits permet d'obtenir une riche signature des stacks PEM dans un vaste domaine fréquentiel. Cette signature reflète les différents phénomènes physico-chimiques et est très sensible aux paramètres de fonctionnement du système. L'évolution de cette signature au court de temps peut être utilisée pour le diagnostic in-situ de d'état de santé des stacks commerciaux dans les conditions réelles de fonctionnement et pour le développement des moyens de pronostic. / Fuel cell technology development requires adequate diagnostic tools, in particular for monitoring the state of health of industrial systems (stacks) under operating conditions. Traditional diagnostic tools require to stop or disrupt the system operating. This thesis aims at the development of an innovative and non-intrusive approach for the diagnostic of PEM (Proton Exchange Membrane) fuel cell stacks. The methodology is based on the measurement of small electrical fluctuations (electrochemical noise). To measure this noise, a high frequency signal acquisition system was used without prior analog filter. These measurements were obtained within the ANR project « Propice » using four measurement campaigns with the collaboration of FCLAB and CEA LITEN. Electrochemical noise Measurements, over several weeks, made it possible to build a rich database. To process these data, different statistical approaches in time, frequency and tempo-frequency domains have been used for the generation of reliable and robust descriptors. It has been shown that the measurement of noise makes it possible to obtain a rich signature of the PEM stacks in a wide frequency range. This signature reflects the various physico-chemical phenomena and it is very sensitive to the operating parameters of the system. The evolution of this signature in short time analysis can be used for an in-situ diagnostic of the state of health of commercial stacks under real operating conditions and for the development of prognostic strategies.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-02-22T13:55:41Z No. of bitstreams: 1 Marcelo Robson de Azevedo Martins da Silva_.pdf: 3067819 bytes, checksum: d7b5c1e064c742114237189fe8cdc3d7 (MD5) / Made available in DSpace on 2018-02-22T13:55:41Z (GMT). No. of bitstreams: 1 Marcelo Robson de Azevedo Martins da Silva_.pdf: 3067819 bytes, checksum: d7b5c1e064c742114237189fe8cdc3d7 (MD5) Previous issue date: 2017-09-27 / Nenhuma / Existem muitas técnicas para reconstrução de objetos tridimensionais em computador, algumas são empregadas em ambientes controlados e outras em ambientes que não necessitam de grande precisão. Shape From Focus é um método bastante conhecido que utiliza uma pilha de fotografias retiradas com diferentes configurações focais para reconstruir um mapa de profundidade bastante preciso. Este método obtém maior estabilidade na reconstrução de objetos muito pequenos ou microscópios, mas recentemente vem sendo utilizado para reconstrução de ambientes. Com isso, o modelo de reconstrução de mapas de profundidade, Shape From Focus, passou a processar maiores quantidades de interferências na pilha de fotografias, como por exemplo, a distorção da lente, o aumento da profundidade de campo, o efeito zoom, entre outros, e também o ruído introduzido pelo ambiente. Este trabalho analisa os efeitos do suporte adaptativo para o janelamento de avaliação do medidor de qualidade de foco do método Shape From Focus. Apesar de diferentes trabalhos sobre este tema utilizarem diversas variações do janelamento de avaliação, o suporte adaptativo pode fornecer uma alternativa para encontrar a estabilidade e confiança na obtenção do mapa de profundidade, limitando o erro introduzido por interferências globais. / There are many techniques for reconstructing three-dimensional objects in a computer, some are used in controlled environments and others in environments that do not require great precision. Shape From Focus is one of the well-known method that uses a stack of cropped photographs with different focal settings to reconstruct a fairly accurate depth map. This method obtains greater stability in the reconstruction of very small objects or microscopes, but has recently been used for reconstruction of environments. As a result, the Shape From Focus reconstruction model began to process greater amounts of interference in the photo stack, such as lens distortion, increased depth of field, zoom effect, among others, as well as noise Introduced by the environment. This work analyzes the effects of the adaptive support for the evaluation window of the focus quality meter of the Shape From Focus method. Although different works on this theme use several variations of the evaluation window, the adaptive support can provide an alternative to find the stability and confidence in obtaining the depth map, limiting the error introduced by global interferences.

The essence of this diploma thesis is the design and implementation of driver for Profinet bus coupler from Phoenix Contact, which use computer's network card for communication. The proposal builds on the knowledge gained from available literature and analysis of Profinet protocol.

Syftet med det här examensarbetet är att presentera process och erfarenheter från mitt konstnärliga musikproduktionsprojekt som genomförts under mitt sista år av min masterutbildning. Genomförandet har bestått av att skapa ett svenskt popmusikalbum där låtar har skapats enskilt, genom samarbeten och tre verk har blivit slutförda och distribuerats på streamingtjänster så som Spotify och YouTube. Vidare är syfte att presentera en modell med hjälp av mitt konstnärliga arbete där det prövas potentiella omformuleringar för yrkesroller inom låtskapande. Dessa termer ska i sin tur underlätta rolldefinition inom låtskapande och även ge utrymme för att förtydliga den ideella rätten som medverkande i ett konstnärligt verk har. Med utgångspunkt till att musikproducenten ofta hamnar i en multikompetent position så har jag valt att låna begrepp från systemutvecklarens yrkesvärld för att skapa modellen. Begreppen jag valt att låna består av back-end, front-end och full-stack och avsikten är att bryta upp paraplybegrepp såsom ”låtskrivare, producent och performer” och även kunna bidra till tydligare rekryteringsprocesser för samarbeten inom låtskapande. / The purpose of this master’s thesis is to present the process and experiences of my music production project that was carried out during the last year of my masters’ studies. The project’s creative content is a Swedish pop album which created through collaborative and independent work. Three single releases and one music video have been released and distributed through the course of the project on streaming platforms such as Spotify and YouTube. In addition to the making of the album I have chosen to create a model to use as a frame for potential recruitment instances of creative collaborations, improve role definition and develop a more accurate method to credit rights holder’s moral credentials as a contributor to an artistic work. The root cause of this model is that a music producer often finds themselves as a multicompetent keyperson in creative collaborations where the lines between different professions overlap. The model is inspired of the software developers job terminology and aims to break up umbrella concept roles such as “songwriter, producer and performer” to facilitate the recruiting process of creative collaborations within the crafting of songs. The terminologies inspired out of the software developer’s professions are back-end, front-end and full-stack.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The advent of COTS based network-centric data systems brings a whole new vocabulary into the realm of instrumentation. The Communications and computer industries have developed networks to a high level and they continue to evolve. One of the basic techniques that has proven itself useful with this technology is the use of a “layered architecture.” This paper is an attempt to discuss the basic ideas behind this concept and to give some understanding of the vocabulary that has grown up with it.

Master of Science / Department of Computing and Information Sciences / Eugene Vasserman / The unprecedented growth of ubiquitous computing infrastructure has brought new challenges for security, privacy, and trust. New problems range from mobile apps with incomprehensible permission (trust) model to OpenSSL Heartbleed vulnerability, which disrupted the security of a large fraction of the world's web servers. As almost all of the software bugs and flaws boil down to programming errors/misalignment in requirements, we need to retrace back Software Development Life Cycle (SDLC) and supply chain to check and place security & privacy consideration and implementation plan properly. Historically, there has been a divergent point of view between security teams and developers regarding security. Security is often thought of as a "consideration" or "toll gate" within the project plan rather than being built in from the early stage of project planning, development and production cycles. We argue that security can be effectively made into everyone's business in SDLC through a broader exploration of the users and their social-cultural contexts, gaining insight into their mental models of security and privacy and usage patterns of technology, trying to see why and how security practices being satisfied or not-satisfied, then transferring those observations into new tool building and protocol/interaction design. The overall goal in our current study is to understand the common challenges and/or misconceptions regarding security-related issues among developers. In order to investigate into this issue, we conduct a mixed-method analysis on the data obtained from Stack Overflow(SO), one of the most popular on-line QA sites for software developer community to communicate, collaborate, and share information with one another. In this study, we have adopted techniques from mining software repositories research paradigm and have employed topic modeling for analyzing security-related topics in SO dataset. To our knowledge, our work in SO data mining is one of the earliest systematic attempts to understand the roots of challenges, misconceptions, and deterrent factors, if any, among developers while they try to implement security features during software development. We argue that a proper understanding of these issues is a necessary first step towards "build security in" culture in SDLC.

The world of industrial manufacturing has changed a lot during the past decades. It has gone from a labour-intensive process of manual control of machines to a fully connected and automated process. The next big leap in industrial manufacturing is known as industry 4.0 or smart manufacturing. With industry 4.0 comes increased integration between IT systems and the factory floor. This change has proven challenging to implement into existing factories many with the intended lifespan of several decades. One of the single most important parameters to measure is the operating hours of each machine. This information can help companies better utilize their resources and save huge amounts of money.  The goal is to develop a solution which can track the operating hours of the machines using image analysis and the signal lights already mounted on the machines. Using methods commonly used for traffic light recognition in autonomous cars, a system with an accuracy of over 99% during the specified conditions, has been developed. It is believed that if more diverse video data becomes available a system, with high reliability that generalizes well, could be developed using similar methodology. / Industriell tillverkning har förändrats mycket under de senaste decennierna. Det har gått från en process som krävt mycket manuellt arbete till en process som är nästan helt uppkopplad och automatiserad. Nästa stora steg inom industriell tillverkning går under benämningen industri 4.0 eller smart tillverkning. Med industri 4.0 kommer en ökad integration mellan IT-system och fabriksgolvet. Denna förändring har visat sig vara särskilt svår att implementera i redan existerande fabriker som kan ha en förväntad livstid på flera årtionden. En av de viktigaste parametrarna att mäta inom industriell tillverkning är varje maskins operativa timmar. Denna information kan hjälpa företag att bättre utnyttja tillgängliga resurser och därigenom spara stora summor pengar. Målet är att utveckla en lösning som, med hjälp av bildanalys och de signalljus som maskinerna kommer utrustade med, kan mäta maskinernas operativa timmar. Med hjälp av metoder som vanligen används för trafikljusigenkänning i autonoma fordon har ett system med en träffsäkerhet på över 99% under de förutsättningar som presenteras i rapporten utvecklats. Om mer video med större variation blir tillgänglig är det mycket troligt att det går att utveckla ett system som har hög pålitlighet i de flesta produktionsmiljöer.

Detta arbete fokuserar på att utveckla två webbapplikationer i ramverken Django och Node.js tillsammans med Express för att besvara frågan av vilket ramverk som erhåller bäst söktider utifrån en Q&A plattform som använder en PostgreSQL databas vars innehåll är delar av Stack Overflow datasetet. Ramverken jämförs med hjälp av metoden experiment på grund av fördelarna som det erbjuder. Resultatet blev att Node.js gav bättre söktider för ett mindre webbapplikationer medan Django presterade bättre för större webbapplikationer. Genom att halvera storleken av sökresultatens kroppstext till 150 tecken fick Node.js söktider som i snitt var bättre än Django vid större projekt. Antalet sökresultat har en inverkan där vardera ramverk har sina egna intervaller där de ger bäst söktider. Kortsiktigt kan arbetet fortsätta genom att utföra ytterligare mätningar för respektive faktor, långsiktigt kan dessa ramverk jämföras med andra för att se om dessa två ligger bland de bättre eller sämre för denna tillämpningen.

The Watershed Development Programme has gained growing support among development policy planners since the 1980s in India. This programme is designed to facilitate sustainable rural development by building irrigation capacity of the, otherwise, rainfed agricultural regions. Irrigation capacity is built via the adoption of various soil and water conservation measures, which then facilitate recharge of groundwater tables within an identified micro-watershed (typically consisting of one or two village communities). The recharged groundwater table becomes the natural resource base from which farming households draw water for irrigation by investing in wells or other such assets. The management of micro-watersheds are based on the principles of community based natural resource management. However, the irrigation access (wells) to this common pool resource of groundwater is privately and individually owned which deters effective monitoring of resource use through collective action. This thesis is built on Ostrom's sustainability of socio-ecological systems (SES) framework and uses a three-essay format. Each essay uses econometric techniques in an attempt to identify particular factors that enable self-organizing ability of communities dependent on groundwater-based irrigation system for generating better livelihoods. The fieldwork was conducted in three villages belonging to the semi-arid districts of Ahmednagar and Jalna in the state of Maharashtra. Quantitative and some qualitative data was collected from nearly 670 households through household surveys. The thesis is organised as three core essays and three supporting chapters. Chapter 1 provides a background to WDP in India and sets the context for the research questions. Chapter 2 presents the literature survey and provides the rationale for choosing SES framework over sustainable livelihoods. It also discusses the broader research methodology. At the end, chapter 3 includes a consolidation of inferences drawn from each of the three essays, and identifies their potential applications and future research direction. The three essays address the research questions raised in this thesis. The first essay analyses the role that knowledge of the resource system (micro-watershed) among resource users, plays in modifying individual farmer's irrigation demand (modelled as crop choice). Two watershed communities located on either side of the ridge line of the watershed are compared. The second essay analyses the role that social capital plays in encouraging self-organization in the community. Social capital is modelled as social betweenness scores calculated by applying Social Network Analysis. A comparison between two villages located in two districts belonging to two different rainfall zones is made. The third essay conceptualizes 'water stack' (collection of irrigation access points) that a farming household owns. The relation between the water stack of the households and the resource use norms in the community is analysed. A comparative analysis between all the three villages is made in this essay. Knowledge of the resource system, social capital and continued support from the agricultural extension agency were found to encourage self-organization and enforcement of resource use norms, resulting in good health of the micro-watershed system.