Cost efficient operation and maintenance strategies are crucial for reducing cost of wind energy. Since the regime change from feed-in tariffs to an auction-based bidding system for capacity in most European wind projects, levelized cost of energy is challenged constantly. Therefore, new technologies such as new controllers are developed to improve operation and to increase profit. Previous research studies demonstrated the advantage of increased power output of wake redirection control. However, understanding and quantifying the impact of wind farm control technologies on operation and maintenance strategies is inevitable to evaluate the economic feasibility of such new technologies. Thus, an event-based O&M simulation tool has been developed. Besides general modules, such as the wind turbine model, the weather forecasting model and a model for simulating corrective and planned maintenance, the developed tool also takes wake effects into account. This allows considering different power productions for each individual turbine and a failure rate distribution within the wind farm which is based on altering loads on the different components. Both aspects are driven by changes in operation when applying a new controller technology. Exemplarily, the economic feasibility of a closed-loop active wake steering control has been analysed. Main achievements of this study are the possibility to quantify the impact of the active wake steering control on O&M related KPIs. Results show that additional loads caused by applying yaw-misalignment and redirecting wake, lead to an increase in OPEX. However, the achieved energy production gain and thus related additional revenue exceeds additional cost in the case study. Nonetheless, the study reveals that the profitability of the controller is highly dependent on the electricity price which can be acquired during the wind farm’s lifetime.

This report describes the development and testing of the upgraded Control and Monitoring (C&Mu) system for the TOFOR neutron spectrometer. TOFOR is currently performing plasma diagnostics for the JET experimental fusion reactor. The purpose of the C&Mu system is to enable monitoring of the amplitude dependent time delays of TOFOR. In order to perform this monitoring function the C&Mu system must comprise a pulsed light source with variable intensity and a reference time signal. In this work a reference time signal has been retrieved from a laser comprising a motorized polarizer. This has been accomplished by installing a photomultiplier tube and a beamsplitter cube. The beamsplitter cube splits the laser light into two parts and directs one part into the photomultiplier tube. The photomultiplier tube converts the light into an electrical reference time signal. A control program has been developed for the motorized polarizer, enabling the user to vary the intensity of the light over the interval from 0% to 100%. The C&Mu system has been performance tested and it was found that the time resolution of the system is about 0.1ns and the time stability of the system is about 0.12ns over 27 hours. The system is more than adequate to monitor variations in time delays at TOFOR of several nanoseconds, over a full JET day. The C&Mu system is ready to be installed on TOFOR.

The work is about development of spain retailing chain in the field of textile and clothing. The goal of work is finding development the company during timeframe and comparing position of company with competitions.

Wind power has been a leading energy source in the renewable energy sector. The offshore wind power industry is rapidly growing, having the advantages of great wind resources, with minimum impact on residential areas; however, the high O&M costs add significantly to the LCOE, and present a challenge to the project developers and operators. The objective of this Thesis is to develop an optimisation method aiming to optimise the O&M vessel fleet in terms of its size and mix, and implement it into a spreadsheet-based tool. At first, a review on the available literature was conducted, in order to establish the theoretical background on the topics of maintenance, optimisation and O&M vessels, and identify the O&M strategies used in offshore wind power. The optimisation method developed focuses on the implementation of different O&M strategies,and is mainly based on the vessel contracts strategy, which aims to acquire lease contracts of various vessel types, including helicopters, available in the market to support the maintenance activities of an offshore wind farm. The model developed consists of calculation modules and introduces a 5-stage weather data filtering process for the estimation of the operational weather window, a WT components' failures forecast method, and a 2-stage optimisation process. The model was applied on a case study of a fictitious offshore wind farm, by using measured and realistic input data, in order to examine its efficacy. The model's outputs generated presented the optimal O&M vessel fleet for three different scenarios (mean, best case, and worst case), together with the optimal allocation of the failure repairs to each O&M vessel, and the corresponding O&M costs.

Cette étude fournit un aperçu des tendances qui existent dans la littérature concernant le gouvernement électronique et le potentiel que ces systèmes ont pour les gouvernements, les entreprises, les employés et les citoyens dans la perspective des pays en développement. Pour comprendre la nature multidimensionnelle des systèmes de gouvernement électronique, cette étude présente un cadre de l'adoption par les citoyens de services du gouvernement électronique en intégrant la littérature sur l'acceptation de technologies et sur le succès du système d'information ainsi que les croyances d'attitude et de la société. Le modèle a été testé par une étude empirique au moyen de deux enquêtes, un questionnaire papier et une autre enquête sur internet. La modélisation d’équation structurelle a été utilisée pour tester les hypothèses.Les résultats de la recherche ont montré que par la capacité perçue à utiliser, le bénéfice fonctionnel, la confiance dans l'internet, la confiance dans le gouvernement et la satisfaction des utilisateurs sont de forts prédicteurs de l'intention des citoyens d’adopter des services de gouvernement électroniques. Nous trouvons également que l'effet de la qualité de l'information et la qualité du système sur l'adoption de l’e-gouvernement est totalement médiée par la capacité perçue à utiliser, le bénéfice fonctionnel, la confiance dans l'internet, la confiance dans le gouvernement et la satisfaction des utilisateurs. La capacité perçue à utiliser et la confiance dans le gouvernement s'avèrent être de significatifs médiateurs de la relation entre la qualité de service et l'adoption des services gouvernementaux en ligne. Nous ne trouvons pas d'effet direct significatif de risque perçu de terrorisme sur l'adoption des services gouvernementaux en ligne, cependant, nous trouvons un effet indirect par le bénéfice fonctionnel. Par ailleurs, nous trouvons un effet significatif du sexe, niveau d'éducation et du niveau d'expérience (avec Internet et avec les sites web du gouvernement) sur l'adoption des services gouvernementaux en ligne par les citoyens. On a constaté que l’âge n'avait pas d'effet significatif sur l'adoption des services gouvernementaux en ligne.En outre, la recherche fournit certaines suggestions utiles et implications pour les milieux académiques et les professionnels des services gouvernementaux en ligne. Cela permettra également de réduire les confusions dans l'esprit des citoyens, au sujet de l’adoption de l'e-gouvernement / Globalization has increased the importance of internet as a medium of communication almost in all aspects of our lives. The current exploratory research provides an insight into the trends that exist within literature concerning the area of Electronic Government (e-government) and the potential these have for the governments, businesses, employees and citizens in perspective of the developing countries. Globally the pace of implementing e-government services is rapidly increasing; however, despite high levels of investment, a broad range of applications, and various methods of access citizens have shown relatively low levels of usage of e-government services making it an interesting area of research. To encompass the multi-dimensional nature of e-government systems the current study presents a framework of citizens’ adoption of e-government services by integrating technology acceptance and information systems (IS) success literature along with citizens’ attitudinal and societal beliefs. In the proposed framework, the qualities of e-government websites such as perceived information quality (PIQ), perceived system quality (PSYQ) and perceived service quality (PSQ) along with social influence (SI), perceived risk of terrorism (PRT) are posited to influence citizens’ adoption of e-government services (ADP) directly and indirectly through perceived ability to use (PATU), perceived functional benefit (PFB), trust in the medium (TM), trust in the government (TG) and user satisfaction (SAT). The research uses a citizen-centric approach to determine citizens’ overall acceptability/adoptability of e-government services. Although we may generalize the results to other countries, yet the primary intention of this research is to shed light on how to approach, manage and implement such projects in developing countries. The model has been examined through an empirical study using paper-based along with a web-based survey. Structural equation modeling has been used to test the proposed hypotheses. The results of the research show that perceived ability to use, perceived functional benefit, trust in medium, trust in government and user satisfaction are strong predictors of citizens’ adoption of e-government services. We also find evidence that the effect of perceived information quality and perceived system quality on adoption of e-government services is totally mediated by perceived ability to use, perceived functional benefit, trust in medium, trust in government and user satisfaction. Perceived ability to use and trust in government are found to be significant mediators on the relationship between perceived service quality and adoption of e-government services. We do not find any significant direct effect of perceived risk of terrorism on adoption of e-government services rather we find an indirect effect through perceived functional benefit. We also find that perceived ability to use, trust in medium and trust in government partially mediate the relationship between social influence and adoption of e-government services. Moreover, we find significant effect of gender, education level, experience with internet and with e-government websites on citizens’ adoption of e-government services. Age is found to have no significant effect on citizens’ adoption of e-government services. Further, the research provides some useful suggestions and implications for the academician and practitioners of e-government services assisting them in designing and implementing policies and strategies to increase the adoption of e-government services. This will also help reduce confusions in the minds of citizens, regarding e-government adoption

In recent years, digital twins (DT) have gained traction in enhancing operation and maintenance procedures across various industrial sectors, such as manufacturing, energy, and aerospace. Yet their utilization remains more limited in the built environment. The aim of this paper is to investigate the current conceptualizations of DTs within the context of the Swedish built environment, shedding light on the maturity of DTs for built assets and the key value drivers influencing their adoption. The study reveals that DTs for built assets are in early developmental stages, lacking the maturity required to encompass the full spectrum of attributes inherent in a conventional DT. Despite stakeholders labeling these initiatives as DTs, our findings indicate a closer alignment with the concept of BIM-based digital models. This observation resonates with existing literature, highlighting the absence of a universally accepted definition for DTs. Within the Operations and Maintenance (O&M) phase, we have identified the following four primary value drivers shaping the adoption of BIM-based DTs: 1) commercial transparency and trusted transactions, 2) efficiency and cost reduction in routine operations, 3) operational continuity, and 4) added services. These findings contribute to the ongoing discourse surrounding the convergence of BIM and DTs, offering insights into the practical implications and value propositions that drive the integration of these technologies within the built environment. / Under de senaste åren har användningen av digitala tvillingar (DT:ar) blivit allt vanligare för drift- och underhållsförfaranden inom olika industrisektorer, såsom tillverkning, energi och flyg- och rymdindustrin. Användningen är dock fortfarande begränsad inom bygg- och fastighetsbranschen. Syftet med denna studie är att undersöka de nuvarande konceptualiseringarna av DT:ar inom ramen för den svenska fastighetsbranschen, belysa mognaden hos tekniken och undersöka de viktigaste värdedrivande faktorerna som påverkar utvecklingen och användningen i drift- och underhåll av fastigheter. Studien visar att användningen av DT:ar i fastighetsbranschen befinner sig i ett tidigt utvecklingsstadie och att begreppet inom industrin inte helt överensstämmer med visionen kring konceptet. Resultaten stämmer överens med befintlig litteratur, som belyser avsaknaden av en allmänt accepterad definition för DT:ar. I drift- och underhållsfasen har vi också identifierat följande fyra primära värdedrivande faktorer för användingen av BIM-baserade DT:ar: 1) kommersiell transparens och pålitliga transaktioner, 2) kostnadsbesparingar i rutinmässigt drift- och underhållsarbete, 3) kontinuerligt driftsarbete, samt 4) tilläggstjänster. Resultaten från denna studie bidrar till den pågående diskussionen om koncepten BIM och DT, och ger ytterligare insikt i de praktiska värdeskapande processerna och belyser användningsområden av DT:ar i fastighetsbranschen.

Computing / M. Sc. (Information Systems)

Computing / M. Sc. (Information Systems)

A combination of theoretical perspectives is used to create a rich description of student reasoning when facing a highly-geometric electricity and magnetism problem in an upper-division active-engagement physics classroom at Oregon State University. Geometric reasoning as students encounter problem situations ranging from familiar to novel is described using van Zee and Manogue's (2010) ethnography of communication. Bing's (2008) epistemic framing model is used to illuminate how students are framing what they are doing and whether or not they see the problem as geometric. Kuo, Hull, Gupta, and Elby's (2010) blending model and Krutetskii's (1976) model of harmonic reasoning are used to illuminate ways students show problem-solving expertise. Sayer and Wittmann's (2008) model is used to show how resource plasticity impacts students' geometric reasoning and the degree to which students accept incorrect results. / Graduation date: 2013