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Degerman, Engfeldt Johnny. "Predicting Electrochromic Smart Window Performance." Licentiate thesis, KTH, Tillämpad elektrokemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-95167.
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The building sector is one of the largest consumers of energy, where the cooling of buildings accounts for a large portion of the total energy consumption. Electrochromic (EC) smart windows have a great potential for increasing indoor comfort and saving large amounts of energy for buildings. An EC device can be viewed as a thin-film electrical battery whose charging state is manifested in optical absorption, i.e. the optical absorption increases with increased state-of-charge (SOC) and decreases with decreased state-of-charge. It is the EC technology's unique ability to control the absorption (transmittance) of solar energy and visible light in windows with small energy effort that can reduce buildings' cooling needs. Today, the EC technology is used to produce small windows and car rearview mirrors, and to reach the construction market it is crucial to be able to produce large area EC devices with satisfactory performance. A challenge with up-scaling is to design the EC device system with a rapid and uniform coloration (charging) and bleaching (discharging). In addition, up-scaling the EC technology is a large economic risk due to its expensive production equipment, thus making the choice of EC material and system extremely critical. Although this is a well-known issue, little work has been done to address and solve these problems. This thesis introduces a cost-efficient methodology, validated with experimental data, capable of predicting and optimizing EC device systems' performance in large area applications, such as EC smart windows. This methodology consists of an experimental set-up, experimental procedures and a twodimensional current distribution model. The experimental set-up, based on camera vision, is used in performing experimental procedures to develop and validate the model and methodology. The two-dimensional current distribution model takes secondary current distribution with charge transfer resistance, ohmic and time-dependent effects into account. Model simulations are done by numerically solving the model's differential equations using a finite element method. The methodology is validated with large area experiments. To show the advantage of using a well-functioning current distribution model as a design tool, some EC window size coloration and bleaching predictions are also included. These predictions show that the transparent conductor resistance greatly affects the performance of EC smart windows.Byggnadssektorn är en av de största energiförbrukarna, där kylningen av byggnader står för en stor del av den totala energikonsumtionen. Elektrokroma (EC) smarta fönster har en stor potential för att öka inomhuskomforten och spara stora mängder energi för byggnader. Ett elektrokromt fönster kan ses som ett tunnfilmsbatteri vars laddningsnivå yttrar sig i dess optiska absorption, d.v.s. den optiska absorptionen ökar med ökad laddningsnivå och vice versa. Det är EC-teknologins unika egenskaper att kunna kontrollera absorptionen (transmittansen) av solenergi och synligt ljus i fönster med liten energiinsats som kan minska byggnaders kylningsbehov. EC-teknologin används idag till att producera små fönster och bilbackspeglar, men för att nå byggnadsmarknaden är det nödvändigt att kunna producera stora EC-anordningar med fullgod prestanda. En välkänd utmaning med uppskalning är att utforma EC-systemet med snabb och jämn infärgning (laddning) och urblekning (urladdning), vilket även innebär att uppskalning är en stor ekonomisk risk på grund av den dyra produktionsutrustningen. Trots att detta är välkända problem har lite arbete gjorts för att lösa dessa. Denna avhandling introducerar ett kostnadseffektivt tillvägagångssätt, validerat med experimentella data, kapabelt till att förutsäga och optimera ECsystems prestanda för anordningar med stor area, såsom elektrokroma smarta fönster. Detta tillvägagångssätt består av en experimentell uppställning, experiment och en tvådimensionell strömfördelningsmodell. Den experimentella uppställningen, baserad på kamerateknik, används i de experimentella tillvägagångssätten så att modellen kan utvecklas och valideras. Den tvådimensionella strömfördelningsmodellen inkluderar sekundär strömfördelning med laddningsöverföringsmotstånd, ohmska och tidsberoende effekter. Modellsimuleringarna görs genom att numeriskt lösa en modells differentialekvationer med hjälp av en finita-element-metod. Tillvägagångssättet är validerat med experiment gjorda på stora EC anordningar. För att visa fördelarna med att använda en väl fungerande strömfördelningsmodell som ett designverktyg, har några prediktioner av infärgning och urblekning av EC-fönster inkluderats. Dessa prediktioner visar att den transparenta strömtilledarresistansen har stor påverkan på EC-fönsters prestanda.
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Issertes-Carbonnier, Eric-Valentin. "Nanowindow: Measuring Window Performance and Energy Production of a Nanofluid Filled Window." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22784.
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Windows reduce heat loss and heat gain by resisting conduction, convection, and radiation using thermal breaks, low-emissivity films, and window gaps. Contrary to advancing these resistive qualities, this research introduced a highly conductive gap medium using Al2O3 nanoparticles dispersed in deionized water to enhance thermal conductivity. The solution harnessed the photothermal properties of Al2O3 nanofluids to trap, store, and transport thermally charged fluids to heat exchangers to preheat air and water, and to generate electricity forming a transparent generator—the Nanowindow.
Seven Nanowindow prototypes with varying orders of air and fluid columns were fabricated and tested using distilled water (H2Owindows) to establish a baseline of performance. A solar simulator was built to avoid environmental radiant flux irregularities providing a uniform test condition averaging 750–850 W/m2, and resulted in an undefined spectral match, Class B spatial uniformity, and Class B temporal stability. All Nanowindows were tested in a calibrated hot box determined to have a ±4% degree of accuracy based on four laboratory samples establishing a framework to conduct U-factor and solar heat gain coefficient (SHGC) measurements.
Four heat exchange experiments and standardized window performance metrics (U-factor, SHGC, and visible transmission) where conducted on seven H2Owindows. The top two H2Owindows were then tested using Al2O3 nanofluids. The highest performing Nanowindow improved total convective heat transfer rates using Al2O3 by 90% over water baseline, and 61% improvement in preheat water experiments. Nanowindows coupled with thermoelectric generators generated a rated voltage of 0.31VDC/0.075ADC per 12in2 Nanowindow, an improvement of 38% over baseline. Standardized window performance metrics confirmed Nanowindow U-factors ranging from 0.23 to 0.54, SHGC from 0.43 to 0.67, and visible transmittance coefficient (VT) ranging from 0.27 to 0.38.
The concept of nature as model system thinking provided a theoretical framework for the research and proof of concept experiment. Ultimately, the experiment shifted window gaps from resisting energy to harnessing solar energy. The Nanowindow thus presents a unique opportunity to turn vast glass facades into transparent generators to offset energy demand, and reduce greenhouse gases.
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Akbari, Sevda. "Studying Window Energy Performance Using Thermal Camera." Thesis, North Dakota State University, 2020. https://hdl.handle.net/10365/31818.
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Windows, which are responsible for 45% of overall heat loss, play a major role in a building’s energy performance. Therefore, it is critical to measure window energy performance for existing buildings. This study aimed to evaluate the energy performance of windows to determine if replacement of windows is necessary. The evaluation was based on window location, height, orientation, and weather condition in a high-rise residential building. A thermal camera was used for measurements and statistical analyses were performed for measured data. Analysis results showed different performance of each side and floor of the building with a significant difference at the 0.05 level due to various temperatures, wind speeds, and directions. This study suggests using more efficient windows on upper floors, particularly from the fourth floor and above is beneficial as well as considering dominant wind speed and direction for the best configuration of window design.
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Li, Chuhe. "A sliding window BIRCH algorithm with performance evaluations." Thesis, Mittuniversitetet, Avdelningen för informationssystem och -teknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-32397.
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An increasing number of applications covered various fields generate transactional data or other time-stamped data which all belongs to time series data. Time series data mining is a popular topic in the data mining field, it introduces some challenges to improve accuracy and efficiency of algorithms for time series data. Time series data are dynamical, large-scale and high complexity, which makes it difficult to discover patterns among time series data with common methods suitable for static data. One of hierarchical-based clustering methods called BIRCH was proposed and employed for addressing the problems of large datasets. It minimizes the costs of I/O and time. A CF tree is generated during its working process and clusters are generated after four phases of the whole BIRCH procedure. A drawback of BIRCH is that it is not very scalable. This thesis is devoted to improve accuracy and efficiency of BIRCH algorithm. A sliding window BIRCH algorithm is implemented on the basis of BIRCH algorithm. At the end of thesis, the accuracy and efficiency of sliding window BIRCH are evaluated. A performance comparison among SW BIRCH, BIRCH and K-means are also presented with Silhouette Coefficient index and Calinski-Harabaz Index. The preliminary results indicate that the SW BIRCH may achieve a better performance than BIRCH in some cases.
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Pereira, Fernando Oscar Ruttkay. "Luminous and thermal performance of window shading and sunlighting reflecting devices." Thesis, University of Sheffield, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302180.
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Mkandawire, Suzie Jaimie 1978. "The performance of Double Skin Façade window systems by experimental methods." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89879.
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Yun, Geun Young. "Occupant behaviour in buildings : thermal performance implications of window use patterns." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612484.
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Campbell, Sarah Anne. "Looking Outside the Canon: Owen Vincent Dodson'sBoy at the Window." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3677.
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Scholars have viewed African American texts written in the years between 1950 and 1960 as espousing confrontation, protest, and resistance. Although fruitful in identifying large writing trends, much of that scholarship narrowly defines what writing during that time accomplished, leaving out important writers whose writing does not fit the mold. One such writer is Owen Vincent Dodson (1914-1983), who published Boy at the Window in 1951. The novel uses modes of drama including song and call-and-response to invite reader sympathy and identification with characters, and eventually provides reader the opportunity to participate in creating meaning. Dodson's novel subtly combats racism by inviting readers to identify with its young, African American protagonist.
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Hoque, Md Sanaul. "An approach to high performance image classifier design using a moving window principle." Thesis, University of Kent, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250329.
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Wei, Shen. "Preference-based modelling and prediction of occupants window behaviour in non-air-conditioned office buildings." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/14066.
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In naturally ventilated buildings, occupants play a key role in the performance and energy efficiency of the building operation, mainly through the opening and closing of windows. To include the effects of building occupants within building performance simulation, several useful models describing building occupants and their window opening/closing behaviour have been generated in the past 20 years. However, in these models, the occupants are classified based on the whole population or on sub-groups within a building, whilst the behavioural difference between individuals is commonly ignored. This research project addresses this latter issue by evaluating the importance of the modelling and prediction of occupants window behaviour individually, rather than putting them into a larger population group. The analysis is based on field-measured data collected from a case study building containing a number of single-occupied cellular offices. The study focuses on the final position of windows at the end of the working day. In the survey, 36 offices and their occupants were monitored, with respect to the occupants presence and window use behaviour, in three main periods of a year: summer, winter and transitional. From the behaviour analysis, several non-environmental factors, namely, season, floor level, gender and personal preference, are identified to have a statistically significant effect on the end-of-day window position in the building examined. Using these factors, occupants window behaviour is modelled by three different classification methods of building occupants, namely, whole population, sub-groups and personal preference. The preference-based model is found to perform much better predictive ability on window state when compared with those developed based on whole population and sub-groups. When used in a realistic building simulation problem, the preference-based prediction of window behaviour can reflect well the different energy performance among individual rooms, caused by different window use patterns. This cannot be demonstrated by the other two models. The findings from this research project will help both building designers and building managers to obtain a more accurate prediction of building performance and a better understanding of what is happening in actual buildings. Additionally, if the habits and behavioural preferences of occupants are well understood, this knowledge can be potentially used to increase the efficiency of building operation, by either relocating occupants within the building or by educating them to be more energy efficient.
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Alameer, Alameer Marai. "Performance and Design of Retention Anchors in Blast Resistant Windows." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41528.
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Windows in building façade are vulnerable to blast pressures. When subjected to blast shock waves, glass windows may suffer failures, potentially causing serious injuries and casualties to the building occupants due to the flying glass shards and other projectiles. Protective films and laminated glass are widely used to protect windows against blast loads. These techniques have proven to reduce or prevent hazards associated with glass breakage. The use of steel or strengthened aluminum frames also reduce window blast hazards associated with frame failures. However, such measures are not always sufficient to mitigate the blast hazard if window retention anchors do not have sufficient resistance to blast pressures. Research on blast resistant windows is scarce in the literature. Therefore, a comprehensive research project was undertaken to address the behaviour, analysis, and design of window retention anchors. The research program consisted of combined experimental and analytical components. Three main phases were pursued, comprising of: i) Experimental research using a shock tube as blast simulator, ii) Numerical investigation based on three-dimensional finite element method (FEM) of analysis, and iii) Non-linear dynamic analysis of window systems based on a single-degree-of-freedom (SDOF) simplification.
The experimental phase consisted of tests of 23 punched windows mounted on four different types of substrates consisting of structural steel, reinforced concrete, concrete block masonry, and stone masonry. The experimental parameters included window size and aspect ratio, glazing type, protective film thickness, substrate type, as well as the number and pattern of window retention anchors. Two levels of blast pressure-impulse combinations were used as per the recommendations of the U.S General Services Administration (GSA).The numerical phase involved FEM modelling and analysis of selected test windows. The FEM models were first validated against test results. The validated models were then employed to conduct an analytical parametric study. The parameters in this phase consisted of; substrate type, window frame rigidity, anchor fixity level in the substrate, window aspect ratio and size, anchor spacing, and blast pressure-impulse combination. The results demonstrated the significance of design parameters on window response, while also defining anchor force distribution along the window frame.
A simplified SDOF method of analysis was developed for window systems, including the effects of anchor flexibility and substrate rigidity on non-linear response. The analysis approach includes the construction of window resistance functions in pre-break and post-break phases of response, where the latter stage of response is dominated by the membrane action of protective film. The analysis leads to the computation of anchor design forces, which have been validated against anchor shear and axial tension forces recorded experimentally. The SDOF analysis is recommended for use in designing blast-resistant window retention anchors on different substrates.
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Francis, Breeson. "Enhancing TCP Congestion Control for Improved Performance in Wireless Networks." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23254.
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Transmission Control Protocol (TCP) designed to deliver seamless and reliable end-to-end data transfer across unreliable networks works impeccably well in wired environment. In fact, TCP carries the around 90% of Internet traffic, so performance of Internet is largely based on the performance of TCP. However, end-to-end throughput in TCP degrades notably when operated in wireless networks. In wireless networks, due to high bit error rate and changing level of congestion, retransmission timeouts for packets lost in transmission is unavoidable. TCP misinterprets these random packet losses, due to the unpredictable nature of wireless environment, and the subsequent packet reordering as congestion and invokes congestion control by triggering fast retransmission and fast recovery, leading to underutilization of the network resources and affecting TCP performance critically. This thesis reviews existing approaches, details two proposed systems for better handling in networks with random loss and delay. Evaluation of the proposed systems is conducted using OPNET simulator by comparing against standard TCP variants and with varying number of hops.
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Isidorsson, Gustav. "Ethics Affecting Business : -Improving Ethical Performance." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-14352.
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Ethics as a subject is investigated in this paper and in particular how ethics can be analyzed in different organizations. The paper investigates how the generic ethical performance (EPE) evaluation model can help organizations to evaluate their ethical performance. The base for the empirical material is collected through qualitative interviews with staff on four different international organizations. The results proclaim that the EPE model can help organizations to narrow down focus and to categorize results, which help organizations to analyze ethical behavior. If the EPE model is complemented with an improvement model (the Deming cycle) an ethical improvement model is created. Conclusions are that evaluating ethical performance is not simple and the results can be ambiguous. The EPE model should be seen as a tool in generic cases and not as the only way of evaluating ethics. If ethics is processed according to the Deming cycle small steps of continuous improvement should help organizations to improve ethical performance. The more you study something the more you realize the complexity of it. Opening doors to new knowledge is like finding yourself in a labyrinth. Some ways are leading to dead ends and sometime you get lost. But when you have been walking in the labyrinth for a while you tend to recognize how the different paths are connected and a web is revealed. This study reveals a gap between theoretical knowledge and knowledge about how to implement and use theories of ethics in “real life” situations. The paper ends with ideas for future possible research, the Ethical Improvement Model (EIM) created in this paper is brought forward as a suggestion.
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Chen, Jianhao. "Investigation of CdS Nanowires and Planar Films for Enhanced Performance as Window Layers in CdS-CdTe Solar Cell Devices." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/27.
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Cadmium sulfide (CdS) and cadmium telluride (CdTe) are two leading semiconductor materials used in the fabrication of thin film solar cells of relatively high power conversion efficiency and low manufacturing cost. In this work, CdS/CdTe solar cells with a varying set of processing parameters and device designs were fabricated and characterized for comparative evaluation. Studies were undertaken to elucidate the effects of (i) each step in fabrication and (ii) parameters like thickness, sheet resistance, light absorptivity solution concentration, inert gas pressure etc. Best results were obtained when the thickness of CdS planar film for the window layer was in the range of 150 nm to 200 nm. Also, CdS nanowires were fabricated for use as the window layer in CdS-CdTe solar cells. Their materials characteristics were studied with scanning electron microscopy (SEM) and X-ray Diffraction (XRD). Spectral absorption measurements on the planar CdS films and nanowire CdS layers were performed and results compared. It was established that the nanowire CdS design was superior because its absorption of sunlight was far less than that of planar CdS film, which would lead to enhanced performance in the CdS-CdTe solar cell through higher short circuit current density and higher open circuit voltage. Diode behavior of CdS-CdTe devices on planar CdS and nanowire CdS was analyzed and compared.
KEYWORDS: Thin Film Solar Cell, Nanowire, UV Absorption, Open-circuit Voltage, Close Space Sublimation
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Ferreira, Diogo Jorge Alves. "Porto sem papel e desempenho portuário: JUP e JUL." Master's thesis, Instituto Superior de Economia e Gestão, 2019. http://hdl.handle.net/10400.5/19298.
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Mestrado em Ciências EmpresariaisO presente trabalho tem como propósito estudar a avaliação e as implicações da desmaterialização documental no desempenho portuário, objetivando-se: (i) Analisar os procedimentos da JUP e os seus efeitos na qualidade do serviço portuário; (ii) Analisar os procedimentos da JUL e seus efeitos na qualidade do serviço portuário; (iii) Analisar o efeito conjunto da JUP e JUL no desempenho portuário. Optou-se por um tipo de investigação com as características dos estudos quantitativos e não experimentais em corte transversal, descritivos e correlacionais, no qual se procura estudar o modo como as variáveis independentes (características da JUP e características da JUL) se refletem na variável dependente (satisfação dos clientes). O instrumento de recolha de dados foi o inquérito por questionário elaborado ad hoc. A amostra em estudo é do tipo não probabilístico por conveniência ou acidental, constituída por 32 inquiridos, nomeadamente de agências de navegação (43,8%), transitários (28,1%), despachante oficial (12,5%), autoridade portuária (6,3%), operadores ferroviários (6,3%) e operador terminal (3,1%). Na globalidade, os inquiridos têm mais conhecimento da JUP comparativamente à JUL, uma vez que lhe reconheceram mais características. Os clientes mais satisfeitos são os que reconhecem que a JUP permite a informação do transporte ferroviário (p=0,015). Os inquiridos que consideram que a JUL permite a notificação prévia da chegada do camião/comboio manifestam mais satisfação (p=0,33).
This work aims to study the evaluation and implications of documentary dematerialization on port performance, aiming to: (i) analyze the procedures of the LPW and their effects on the quality of port service; (ii) Analyze LSW procedures and their effects on port service quality; (iii) Analyze the joint effect of LPW and LSW on port performance. We opted for a type of investigation with the characteristics of quantitative and non-experimental cross-sectional, descriptive and correlational studies, which seeks to study how the independent variables (LPW characteristics and LSW characteristics) are reflected in the dependent variable (client?s satisfaction). The data collection instrument was the ad hoc questionnaire survey. The sample under study is non-probabilistic for convenience or accidental type, consisting of 32 respondents, namely shipping agencies (43.8%), freight forwarders (28.1%), official dispatcher (12.5%), port authority (6.3%), rail operators (6.3%) and terminal operator (3.1%). Overall, respondents are more knowledgeable about the LPW compared to the LSW, as they have recognized more features. The most satisfied customers are those who recognize that LPW allows rail transport information (p=0.015). Respondents who consider that LSW allows advance notification of the arrival of the truck /train express more satisfaction (p=0.33).
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Ramirez, David de Freitas. "O Impacto da colocação secundária na performance das firmas." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5818.
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O objetivo do presente trabalho foi examinar o desempenho das firmas em períodos próximos à realização da colocação secundária, perfazendo uma análise das pesquisas relatadas sobre o evento. Como constatado na literatura, os agentes alienam sua participação acionária por motivos diversos e, dependendo do tipo de informação que o alienante possui, a performance das ações e operacional das firmas tendem a ser robusto em momentos próximos ao fenômeno e fraco conforme vai se distanciando do mesmo. Foi a demonstração dessa repercussão que se buscou comprovar nesse trabalho, tratando de diferenciar os efeitos no mercado quando a venda é feita por um detentor de informação privilegiada da que é realizada por um alienante que não detém esse tipo de informação. O que se depreende da literatura é que os agentes no momento da venda de suas ações tendem a se aproveitar da janela de oportunidade. Apresentando ainda as teorias levantadas sobre o tema, percebe-se que elas possuem um poder de explicação sobre o que ocorre no mercado de capitais no momento da distribuição secundária.The objective of this study was to examine the performance of firms in periods near completion of secondary offering, executing an analysis of the research reported on the event. As noted in the literature, shareholders sell shares for various reasons and, depending on the type of information that the he carry, the stock and operational performance of the firms tend to be robust at times closest to the phenomenon and poor as will moving away from same. Was the demonstration of this effect which sought to prove in this work, trying to differentiate the effects on the market when the sale is made by an insider with respect to non-insider. What is clear from the literature is that agents at the time of sale of their shares tend to take advantage of the window of opportunity. Yet anchoring in theories raised on the topic, it is clear that they have a powerful explanation of what happens in the capital market at the time of the secondary distribution.
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Georgievskaya, Liudmila. "A Performer's Guide to Samuil Feinberg's Sonata No. 6: A Window into Russian School Pianism." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011846/.
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Samuil Feinberg was an important performing pianist, composer, and one of the protagonists of Russian Piano School. Among his numerous piano compositions, the Sixth Sonata is one of the most complex and illustrative of his deeply personal musical ideas. The following performer's guide offers some ideas on interpreting and performing the sonata from the perspective of Russian school pianism. Having trained in Russia for nearly a decade with two of Feinberg's most eminent disciples and assistants (Tatiana Galitskaya and Liudmila Roschina) makes this author part of living chain back to his pedagogical principles. I will draw upon my knowledge and expertise to illustrate how interpretation of Feinberg's Sonata No. 6 embodies many of the particular and subtle aspects of the Russian piano school technique.
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Voicu, Laura M. "Modeling the Throughput Performance of the SF-SACK Protocol." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3904.
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Besides the two classical techniques used to evaluate the performance of a protocol, computer simulation and experimental measurements, mathematical modeling has been used to study the performance of the TCP protocol. This technique gives an elegant way to gain insights when studying the behavior of a protocol, while providing useful information about its performance.
This thesis presents an analytical model for the SF-SACK protocol, a TCP SACK based protocol conceived to be appropriate for data and streaming applications. SF-Sack modifies the multiplicative part of the Additive Increase Multiplicative Decrease of TCP to provide good performance for data and streaming applications, while avoiding the TCP-friendliness problem of the Internet. The modeling of the SF-SACK protocol raises new challenges compared to the classical TCP modeling in two ways: first, the model needs to be adapted to a more complex dynamism of the congestion window, and second, the model needs to incorporate the scheduler that SF-SACK makes use of in order to maintain a periodically updated value of the congestion window. Presented here is a model that is progressively built in order to consider these challenges. The first step is to consider only losses detected by triple-duplicate
acknowledgments, with the restriction that one such loss happens each scheduler interval. The second step is to consider losses detected via triple-duplicate acknowledgments, while eliminating the above restriction. Finally, the third step is to include losses detected via time-outs. The result is an analytical characterization of the steady-state send rate and throughput of a SF-SACK flow as a function of the loss probability, the round-trip time (RTT), the time-out interval, and the scheduler interval.
The send rate and the throughput of SF-SACK were compared against available results for TCP Reno. The obtained graphs showed that SF-SACK presents a better performance than TCP. The analytical model of the SF-SACK follows the trends of the results that are presently available, using both the ns-2 simulator and experimental measurements.
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Nilsson, Annica M. "Daylighting Systems : Development of Techniques for Optical Characterization and Performance Evaluation." Doctoral thesis, Uppsala universitet, Fasta tillståndets fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-183307.
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Successful integration of daylighting systems requires the ability to predict their performance for given climates. In this dissertation, a bottom-up approach is applied to evaluate the optical performance of a selection of daylighting systems. The evaluations are based on the optical properties of the included materials, and part of the dissertation focuses on developing new optical characterization methods. The work on characterization techniques uses an integrating sphere method to characterize the transmittance of light scattering samples more accurately. The method's principle is to reduce the discrepancy in light distribution between the reference and the sample scans by using an entry port beam diffuser. For samples exhibiting distinct light scattering patterns, the benefits of improved uniformity outweigh the errors introduced by the diffusing material. The method is applicable to any integrating sphere instrument, and its simplicity makes it suitable for standard measurements. In addition to normal-hemispherical properties, many daylighting applications require knowledge of the system's spatial light distribution. This dissertation presents a method combining experimental techniques and ray tracing simulations to assess the light distribution from a Venetian blind system. The method indicates that ray tracing based on simplified optical data is inadequate to predict the light distribution for slat materials exhibiting both specular and diffuse properties. Ray tracing is a promising complement to experimental methods used to characterize light guiding or light redirecting systems. Here, spectrophotometric measurements of a scaled mirror light pipe validate a ray tracing model. The model shows excellent agreement with experimental results for both direct and diffuse incident light. The spectral evaluation shows no dramatic color changes for the transmitted light. The ray tracing model is used to evaluate four daylighting systems for a selection of Swedish locations. The percentage of occupied time when the studied systems achieve full design illuminance is relatively low, but the systems provide a valuable contribution to the required illuminance. Additionally, this dissertation provides an overview of available energy efficient windows and illustrates the importance of including the solar energy transmittance when evaluating window energy performance. Overall, this dissertation presents optical characterization techniques for improved performance evaluations of daylighting systems.
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Rathi, Priyanka. "Optimization of Energy Efficient Windows in Office Buildings for Different Climate Zones of the United States." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1334603394.
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Abolghasemi, Moghaddam Saman. "The effects of low-emissivity window films on thermal comfort and energy performance of a historic stone building in cold climate: computer simulations with "IDA ICE"." Thesis, Högskolan i Gävle, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30145.
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Low-emissivity (low-E) window films are designed to improve the energy performance of windows and prevent indoor overheating by solar radiation. These films can be applied to different types of glazing units without the need for changing the whole window. This characteristic offers the possibility to improve the energy performance of the window of old and historic buildings for which preservation regulations say windows should remain more or less unchanged. This research aims to figure out to what extent a low-E window film can improve thermal comfort and energy performance of an old three-storey historic stone building in the cold climate of Mid-Sweden. In this research, first, with help of the simulation software “IDA ICE”, the entire building was modelled without window films in a one-year simulation. Second step was to add the low-E window films (3M Thinsulate Climate Control 75 (CC75)) to all the windows and repeat the simulation. Comparison between the results of the two cases revealed an improvement in energy use reduction as well as the thermal comfort when applying the films. For the application of the window films, a cost analysis using payback method was carried out which showed a long- time payback period. Although an investment with a long-time payback period is considered as a disadvantage, for historic buildings with very strict retrofit regulations specially when it comes to the building’s facades, application of the low-emissivity window films for better energy performance and thermal comfort is among the recommendable measures, but not necessarily the best.
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George, Kiranraj. "Design and Performance Evaluation of 1 Giga Hertz Wideband Digital Receiver." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1183662240.
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Ling, Leng. "Two Essays on Managerial Behaviors in the Mutual Fund Industry Essay 1: A Life-Cycle Analysis of Performance and Growth in U.S. Mutual Funds Essay 2: Can Mutual Fund Window-Dressing Promote Fund Flows?" unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-06132008-144714/.
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Thesis (Ph. D.)--Georgia State University, 2008.Title from file title page. Jason Greene, Gerald Gay, committee co-chairs; Harley Ryan, Conrad Ciccotello, committee members. Electronic text (93 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Oct. 13, 2008. Includes bibliographical references.
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Romsäter, Tara, and Åsa Matti. "Den mytomspunna effekten av IPO : En analys av IPO och dess påverkan på svenska bolags finansiella prestation." Thesis, Södertörns högskola, Företagsekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-43650.
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Purpose: This study is made to analyze and examine effects of an IPO before and after a stock is introduced on the market, and if the age of the company makes a difference on the day it becomes listed. And if it could be associated with an improved financial performance through several assumptions. Theory: This study is based on three different theories, the Pecking Order Theory, Agency Cost Theory and Window-Dressing Theory, but could also be supported by previously recognized research. Method: The theories subjected of the study is based on quantitative elements of deductive and theory-testing approaches in different angles of the company's financial status. Empiries: 54 companies were involved in a study of Initial Public Offering in the years of 2014 and 2015, the selection of the 54 companies were divided in two groups depending on which stock market they were listed on. We then made further research based on three questions. Is getting listed on the stock market an advantage for financial growth? If the age of the company gives it an advantage in financial growth when it gets listed on the stock market? Does it affect the financial growth depending on where the company got listed? Conclusion:Generally we can see a connection between choice of trading venue and the company's age of an IPO does affect the impact of financial growth and performance.Syfte: Studien avser att analysera effekter av en börsnotering innan och efter, samt om ett bolags ålder vid noteringsdagen kan associeras med en förbättrad finansiell prestation genom olika antaganden. Teori: Denna studie utgår från tre teorier, Pecking Order Theory, Agency Cost Theory och Window-Dressing Theory, men även en referensram av tidigare forskning. Metod: Studien utgår från en kvantitativ ansats med inslag av deduktiv- och teoriprövande ansatser. Empiri: Ett urval bestående av 54 bolag studerades utifrån deras börsnotering som skedde år 2014 och 2015. Urvalet av 54 bolag delades upp i två grupper beroende på vilken marknadsplats som de var listade på. Därefter gjordes en vidare undersökning baserat på tre forskningsfrågor. Leder en börsnotering till tillväxt i bolaget? Påverkar valet av handelsplats ett bolags tillväxt vid börsnotering? Är bolagets ålder vid noteringsdagen associerat med förbättrad finansiell prestation? Slutsats: IPO har generellt sett en påverkan på bolags finansiella prestation. Beroende på val av handelsplats gav den finansiella prestationen olika utslag. Samband mellan ett bolags ålder vid en IPO verkade även ha en inverkan på den ekonomiska tillväxten.
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Hultqvist, Adam. "Cadmium Free Buffer Layers and the Influence of their Material Properties on the Performance of Cu(In,Ga)Se2 Solar Cells." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-133112.
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CdS is conventionally used as a buffer layer in Cu(In,Ga)Se2, CIGS, solar cells. The aim of this thesis is to substitute CdS with cadmium-free, more transparent and environmentally benign alternative buffer layers and to analyze how the material properties of alternative layers affect the solar cell performance. The alternative buffer layers have been deposited using Atomic Layer Deposition, ALD. A theoretical explanation for the success of CdS is that its conduction band, Ec, forms a small positive offset with that of CIGS. In one of the studies in this thesis the theory is tested experimentally by changing both the Ec position of the CIGS and of Zn(O,S) buffer layers through changing their gallium and sulfur contents respectively. Surprisingly, the top performing solar cells for all gallium contents have Zn(O,S) buffer layers with the same sulfur content and properties in spite of predicted unfavorable Ec offsets. An explanation is proposed based on observed non-homogenous composition in the buffer layer. This thesis also shows that the solar cell performance is strongly related to the resistivity of alternative buffer layers made of (Zn,Mg)O. A tentative explanation is that a high resistivity reduces the influence of shunt paths at the buffer layer/absorber interface. For devices in operation however, it seems beneficial to induce persistent photoconductivity, by light soaking, which can reduce the effective Ec barrier at the interface and thereby improve the fill factor of the solar cells. Zn-Sn-O is introduced as a new buffer layer in this thesis. The initial studies show that solar cells with Zn-Sn-O buffer layers have comparable performance to the CdS reference devices. While an intrinsic ZnO layer is required for a high reproducibility and performance of solar cells with CdS buffer layers it is shown in this thesis that it can be thinned if Zn(O,S) or omitted if (Zn,Mg)O buffer layers are used instead. As a result, a top conversion efficiency of 18.1 % was achieved with an (Zn,Mg)O buffer layer, a record for a cadmium and sulfur free CIGS solar cell.Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 717
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Memon, Saim. "Design, fabrication and performance analysis of vacuum glazing units fabricated with low and high temperature hermetic glass edge sealing materials." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/14562.
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Vacuum glazing is a vital development in the move to more energy efficient buildings. In vacuum glazing, an evacuated cavity supresses gaseous conduction and convection to provide high thermal resistance. A high vacuum pressure (less than 0.1 Pa) is required and must be maintained by a hermetic seal around the periphery, currently formed with either indium (i.e. low temperature sealing method) or solder glass (i.e. high temperature sealing method). This thesis reports the results of an experimental and theoretical investigation into the development of new low temperature (less than 200°C) and novel high temperature (up to 450°C) glass edge seals. A new low temperature composite edge seal was developed in which double and triple vacuum glazings each of dimensions 300x300mm were fabricated with measured vacuum pressures of 4.6x10-2Pa and 4.8x10-2Pa achieved respectively. A three dimensional finite element model of the fabricated design of composite edge sealed triple vacuum glazing was developed.
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Karlsson, Joakim. "Windows : Optical Performance and Energy Efficiency." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5147-0/.
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Ma, Chenwen. "Retrofitting a Single-family Home with Increased Use of Renewable Energy." Thesis, KTH, Installations- och energisystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215962.
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Buildings account for up to 40% of the total energy use in the world. Directives from the European Union have pointed out the significance of increasing the energy efficiency in buildings. New regulation in countries like Sweden has established that new buildings should fulfil regulations of Nearly Zero Energy Buildings (NZEB), providing the opportunity for renewable energy technologies to achieve these goals. In this paper, the retrofitting potential of renewable energy technologies for a single-family home in Sweden was investigated.The present work studied the characteristics of several renewable energy technologies and their applications for a single-family home in Sweden, including biomass, solar photovoltaics, solar thermal, heat pump, and small-scale wind turbine. Three renewable energy technologies (solar thermal, heat pump and small-scale wind turbine) and one renovation method (window) were selected to investigate. The analysis was made of the current energy use and the potential energy (and cost) savings from each retrofitting of these facilities by means of simulation models using IDA ICE software. The study results show that the proposed renewable energy technologies are technically feasible and economically viable as a source of alternative renewable energy in order to produce clean energy and reduce electricity bills for an electric-heated single-family home located in Sweden. Moreover, the combined retrofitting scheme consist of solar thermal system and window renovation was also proposed and explored. As a result the energy performance of the single-family home would satisfy the nearly-zero energy building requirements and thermal comfort could be maintained at an acceptable level.
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Bergoug, Hakim. "Effet de la durée entre l’éclosion et la mise en élevage des poussins d'un jour sur les performances zootechniques, la santé et le bien-être des poulets de chair." Thesis, Rennes, Agrocampus Ouest, 2017. http://www.theses.fr/2017NSARB297.
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La période d'attente entre le moment d’éclosion (ME) des poussins et leur mise en élevage est critique pour le développement des poulets de chair. Cette période d'attente est composée de la fenêtre d’éclosion (FE: temps qui sépare le ME du premier poussin et la sortie du lot des poussins à l'ouverture des portes d'incubateur), les manipulations post-éclosion et la durée de transport (DT). L'objectif de cette thèse était d'étudier l'effet de la durée de période d'attente sur les performances zootechniques, la santé et le bien-être des poulets durant l'élevage. Notre travail a été divisé en deux études composées de trois expérimentations chacune. La première étude a été axée sur l'effet de FE sur la déshydratation, les performances zootechniques, l'activité enzymatique intestinale et la sévérité des pododermatites des pouletsLa deuxième étude a été axée sur l'effet de DT sur la déshydratation, les performances zootechniques et la sévérité des pododermatites des poulets. Nous avons démontré que les poussins éclos tardivement (0-7h avant l'ouverture de l'incubateur) sont de moins bonne qualité. Ils perdent plus de poids durant les 8 premiers jours d'élevage. Cette perte de poids ne persiste pas jusqu’à l'abattage. Nos observations ont montré qu’après DT de 4-10h, les poussins présentaient une croissance réduite au cours des 3 premières semaines d'élevage par rapport à ceux non transportés mais cet effet ne persistait pas jusqu'à l'abattage. De plus, DT n’avait pas d’effet clair sur la déshydratation, la mortalité, l'efficacité alimentaire et la sévérité des pododermatitesHolding period between hatch time (HT) of chicks in incubator and their placement in farm is critical for broilers’ development. This holding period is composed of hatch window (HW: duration between HT of the first chick and takeoff of the whole batch of chicks from the incubator), post-hatch manipulations and transportation duration (TD) to the farm. The objective of this thesis was to study the effect of the holding period duration on growth performance, health and welfare of broilers during rearing period. Our work was divided into two studies. Each study was composed of three experiments. The first study focused on the effect of the HW on dehydration, growth performances, intestinal enzyme activity and severity of pododermatitis in broilersThe second study focused on the effect of TD on dehydration, animal performance and severity of pododermatitis in broilers. It was shown that late hatched chicks (0-7h before takeoff) are of lower quality. They lose more weight during the first eight days of rearing. This weight loss, does not last until slaughter. Our observations have shown that after a TD of 4 or 10h, the chicks’ growth was reduced during the first three weeks of rearing compared to chicks that were not transported, but this effect did not last until slaughter. In addition, TD had no clear effect on dehydration, mortality, feed efficiency and severity of pododermatitis
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Hamayun, Muhammad, and Nadeem Ahmed. "Performance Evaluation of Windows Communication Foundation’s Interoperability." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-5294.
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Middleware eases the development of distributed applications. Expansion in the enterprise world entails integration of heterogeneous products, and there is a demand for a balance between performance, interoperability and security in the distributed applications. Windows Communication Foundation (WCF) offers a technology to build service-oriented, secure, reliable and interoperable distributed applications. The current literature contains few studies comparing the performance of WCF with other technologies, but it does not address the performance of WCF in a cross-technology communication. This master thesis experimentally evaluates the performance of WCF in unsecure and secure variants. It evaluates the performance in on-machine and cross-machine communication, and it addresses the performance of WCF’s interoperability with ASMX and Java. We have developed the service and client applications in both secure and unsecure variants. The experiments are then conducted using these applications in a laboratory setting. We have measured the performance in terms of throughput, response time, processor and memory utilization during the experiments. Our results show that in unsecure variants, the WCF service in cross-machine communication has the best response time than on-machine communication on small datasets. However, on large datasets the service in on-machine communication has the best response time. In secure variants, the service in on-machine communication has better response time than the cross-machine communication. In both secure and unsecure variants, the service has better throughput and consumed lesser resources in cross-machine communication than in on-machine communication. In case of WCF’s interoperability with ASMX and Java, both the secure as well as unsecure WCF service show more scalable performance for the WCF client than for ASMX and Java clients. The secure as well as unsecure service show better performance for the ASMX client than for the Java client. The unsecure variants of WCF service perform better than the secure variants, except in a few cases of memory utilization. Therefore, the performance of the WCF service degrades due to security.
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Klipper, Laurenz. "Three Essays on Mutual Funds." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19585.
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Der erste Artikel liefert Beweise dafür, dass ein Liquiditätsschock bei geschlossenen Fonds zu einer Liquiditätsverschlechterung bei offenen Fonds führen kann. Unsere Ergebnisse zeigen, dass Aktien von geschlossenen Fonds, die aufgrund eines Marktversagens notverkauft wurden, temporär im Preis sinken. Offene Fonds, die viele der betroffenen Aktien halten, erleiden daraufhin einen Kapitalabfluss, der weitere Notverkäufe bedingt. Dies unterstreicht die Ansteckungsgefahr zwischen den beiden Finanzmärkten. Der zweite Artikel untersucht, ob Fonds, die mit Staatsanleihen handeln, ihr Risiko durch den Wertpapierverleih erhöhen, indem sie die hierbei erhaltenen Sicherheiten risikoreich reinvestieren. Hiermit konsistent finden wir, dass die Returnvolatilität von Fonds ansteigt, je mehr Wertpapiere verliehen werden. Diese Korrelation ist nur evident, wenn der für den Wertpapierverleih verantwortliche Agent bereits in der Vergangenheit solch eine Strategie praktiziert hat. Sie verschwindet hingegen, wenn der Agent Sicherheiten nicht risikoreich reinvestieren kann. Im dritten Artikel stellen wir ein neues Maß vor, mit dem sich die Handelsaktivität von Fonds drei Tage vor den Geschäftsberichten untersuchen lässt. Stark handelnde Fonds halten bei Berichtsschluss mehr Gewinner- und weniger Verliereraktien. Zudem sind die üblichen Maße, die zur Identifizierung von Window Dressing verwendet werden, signifikant höher. Aktien, die in den letzten drei Tagen vor den Juli und Dezember Berichten einen starken Nachfrageüberschuss aufweisen, steigen in dieser Periode um durchschnittlich 20 Bsp. Dieser Anstieg ist nicht durch Informationstheorien erklärbar, da die Preise innerhalb von einer Woche auf ihr ursprüngliches Niveau zurückfallen. Aktien mit hoher Liquidität zeigen geringere Anstiege und kehren schneller zum Ausgangspreis zurück. Die Preisbewegungen lassen sich nicht durch einen einzelnen Faktor, wie Window Dressing oder Portfolio Pumping, erklären.The first paper provides evidence that a liquidity shock to closed-end funds can transmit to open-end funds. Using the failure of the market for auction rate securities we show that forced asset sales of highly levered closed-end funds result in temporary price declines in those assets. Open-end funds that hold significant numbers of the affected stocks in turn experience outflows, forcing them to conduct additional fire-sales. These forced sales induce additional price pressure consistent with financial contagion. The second paper examines whether mutual bond funds increase their risk exposure through securities lending transactions by reinvesting the cash collateral of these transactions in risky assets. Consistent with such behavior, we find that the return volatility of government bond funds increases with the percentage of securities on loan. This relation is only evident among funds whose lending agent likely reinvests the lending collateral riskily and disappears if the lending program is managed by agents who typically cannot make risky reinvestments. The third paper provides a new way to measure the trading activity by mutual funds in the last three days of their reporting periods. Consistent with window dressing, heavy end-of-period (EoP) traders report more winner, fewer loser stocks and higher return and rank gaps, yet perform no better. Stocks with a high positive EoP trade imbalance show significant price increases of about 20 bps at the end of reporting periods in June and December. Inconsistent with information trading, prices revert within a week. Liquid stocks appreciate less strongly and revert more quickly. Finally, we show that window dressing, portfolio pumping, or fund flows alone are unlikely to explain our results.
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Nichols, III James G. "Measurement of Windows Streaming Media." Digital WPI, 2004. https://digitalcommons.wpi.edu/etd-theses/237.
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The growth of high speed Internet connections has fueled an increase in the demand for high quality streaming video. In order to satisfy timing constraints, streaming video typically uses UDP as the default network transport protocol. Unfortunately, UDP does not have any end-to-end congestion control mechanisms, and so in the absence of higher layer congestion control can lead to unfairness and possibly congestion collapse. While there has been research done in video measurement and characterization using custom tools, to the best of our knowledge, there have been no measurement studies where the researchers had control over a commercial streaming media server and client, and control of the network conditions and content. A goal of this research is to characterize the bitrate response of Windows Streaming Media in response to network-level metrics such as capacity, loss rate, and round-trip time. We build a streaming media test bed that allows us to systematically vary network and content encoding characteristics. We analyze responsiveness by comparing streaming media flows to TCP-friendly flows under various streaming configurations and network conditions. We find Windows Streaming Media has a prominent buffering phase in which it sends data at a bitrate significantly higher than the steady-state rate. Overall, Windows Streaming Media is responsive to available capacity, but is often unfair to TCP. Knowledge of streaming media's response to congestion encountered in the network is important in building networks that better accommodate their turbulence. The additional characteristics we measure can be combined to guide emulation or simulation configurations and network traffic generators for use in further research.
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Godbole, Swapnil. "Investigating The Relationship Between Mean Radiant Temperature (MRT) And Predicted Mean Vote (PMV) : A case study in a University building." Thesis, KTH, Installations- och energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-235927.
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Thermal comfort in an indoor environment is largely dependent on the four environmental and two personal parameters which is most commonly measured by the Predicted Mean Vote (PMV) model developed by Fanger. It has been studied that variations in these parameters beyond a range could lead to discomfort complaints. However, little research has been done on the effect of mean radiant temperature variations and its influence on predicted mean vote and thermal comfort specially in an actual building environment. This study aims to investigate the relationship between mean radiant temperature and predicted mean vote in indoor environment. Using the methods of on-site measurement of indoor environmental parameters and subjective votes on thermal sensation in an educational building; it was found that rise in mean radiant temperature lead to rise in PMV value and discomfort vote amongst occupants seated near glazed façade. A very strong positive correlation was found between mean radiant temperature and PMV near the window side of the room under warm and sunny weather conditions. Analysis of indoor environmental data from the several measurement sessions concluded that rise in mean radiant temperature and PMV was not noticed until there was a direct solar transmission through the window. It is advisable to use solar shading on windows, but special consideration should be given to the trade-offs between energy consumption (heating or cooling) and lighting energy consumption. No conclusions could be made in terms of ankle draft discomfort due to experimental limitations and more research would be required to investigate this phenomenon.Termisk komfort inomhusmiljö är till stor del beroende av de fyra miljö och två personlig parametrar som oftast mäts av Predicted Mean Vote (PMV) modell som utvecklats av Fanger. Det har studerats att variationer i dessa parametrar utanför en limit kan leda till missnöjeklagomål. Däremot har lite forskning gjorts på effekten av mean radiant tempratur och dess inverkan på predicted mean vote och termisk komfort speciellt i en verklig byggnadsmiljö. Syftet med denna studie är att undersöka sambandet mellan mean radiant tempratur och predicted mean vote i inomhusmiljö. Användning mätmetoderna av inomhusmiljöparametrar och subjektiva röster av termisk komfort uppfattning i en byggnad för utbildning; det konstaterades att stiga i medel leda mean radiant tempratur att stiga i predicted mean vote värde och missnöje rösta bland byggnad brukarna sitter nära glasfasaden. En väldigt positiv korrelation mellan men radiant tempratur och predicted mean vote nära en fönstersida under varma och soliga väder var noterat. Genom att analysera data av inomhusmiljön från de multipla mätningssessionerna konkluderat att ökningen i mean radiant tempratur och predicted mean vote inte märktes tills det fanns en direkt soltransmission genom fönstret. Det är rekommenderar att använda solskydd på fönster, men med tanke på kompromisser mellan energiförbrukning (värme eller kyla) och ljussättning konsumtion. Inga slutsatser kan göras om luftdrag på fotled grund av experimentella begränsningar och mer forskning skulle krävas för att undersöka detta fenomen.
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Jonsson, Andreas. "Optical Characterization and Energy Simulation of Glazing for High-Performance Windows." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-110716.
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De, Abreu Pedro Felipe. "Modeling the thermal performance of windows using a two-dimensional finite volume model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21338.pdf.
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Ayssa, Abdullah Zeid. "The thermal performance of vernacular and contemporary houses in Sana'a, Yemen." Thesis, Open University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259694.
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O'Keefe, Timothy J. "A comparison of human performance on computer text editing tasks using windowed and non-windowed strategies." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/52315.
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Software packages which use windows have become increasingly popular in the last two years. Their popularity derives from the belief that windows will improve productivity by decreasing task completion time. However, two studies (Silver, 1985 and Davies, Bury and Darnell, 1985) have found this not to be the case. In fact, one of the studies (Davies at al., 1985) found that task completion time was increased when using windows. It is thought that performance using window systems is a function of the number of responses required to be executed as well as the amount of information which must be found and used to complete a task. The purpose of the present study was to determine under what conditions, in terms of memory load and task complexity, performance using windows and non-window strategies differed.
Forty-eight subjects were placed in one of four environments and each performed six editing tasks which varied on complexity and memory load level. Human performance in one windowed environment was compared to three non-window strategies. These three strategies, note-taking, memorizing, or switching between files, were included to allow comparisons in terms of working memory and number and types of responses executed. The tasks required subjects to locate information from a supplementary file and type it into a main file. The three memory load levels which were used required subjects to find either 2, 4 or 8 pieces of information. The two complexity levels referred to the placement of needed information in the supplementary file; whether or not information was located in close proximity to other needed information.
Results indicated that it made little difference which system was used in the low memory load condition. However, as memory load increased, more subjects were found to make errors in the non-window conditions. More responses were executed in the Switch condition than in the Window or Memorization conditions in the high memory load condition. Mental workload was also found to be higher in the Memorization and Switch conditions than in the Window and Notes conditions as memory load increased. Nevertheless, there was no significant interaction for task completion times between Memory Load and Environment. This was thought to be due to a failure to adequately load working memory as well as a failure of a test of verbal and spatial ability to account for individual differences.
It was concluded that the benefits of windows are not apparent until one°s working memory capacity is exceeded. As memory load increases beyond this point, it is thought that memorization will quickly become an inefficient strategy due to limitations of memory capacity. As memory load continues to increase, a switching strategy should become inefficient due to limitations of both memory and response capacities. A strategy of note taking should not become inefficient until a large memory load is placed upon the user. This is because note taking is a well learned uncomplicated response. The benefits of windows include a reduction in the number of responses, errors, and mental workload due to their ability to reduce the amount of mental resources required by providing the user with a very efficient and accurate memory aid.Ph. D.
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Silva, Tiago Manuel Rodrigues da. "Análise numérica e experimental para o desenvolvimento de uma proteção solar com incorporação de materiais de mudança de fase." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17346.
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Doutoramento em Sistemas Energéticos e Alterações ClimáticasO sector dos edifícios é o maior consumidor final de energia na União Europeia. O maior consumo de energia neste sector está associado principalmente ao recurso de sistemas ativos para a climatização dos espaços interiores – aquecimento e arrefecimento. Atualmente, o desenho arquitectónico exterior de escritórios e de edifícios comerciais recorre sistematicamente ao uso de vãos envidraçados e de soluções translúcidas, que aumenta significativamente as perdas térmicas nestas zonas. Os sistemas de armazenamento de energia térmica, utilizando materiais de mudança de fase nos edifícios, é um tema atualmente muito investigado e com rápido desenvolvimento tecnológico. A incorporação de materiais de mudança de fase é atualmente uma solução avançada que permite melhorar o desempenho térmico do edifício, inclusive na aplicação em vãos envidraçados e soluções de proteção solar. O presente trabalho apresenta e analisa a campanha experimental e simulação numérica de um sistema de proteção solar que incorpora materiais de mudança de fase. A campanha experimental é composta por dois compartimentos lado a lado, e cada um deles tem duas proteções solares – um dos compartimentos com a incorporação de materiais de fase e no outro sem. Ambos os compartimentos foram sujeitos a condições climatéricas exteriores similares numa região de clima mediterrânio durante a estação de verão e de inverno. A fachada orientada a sul é um vão envidraçado, o qual tem aplicado o sistema de proteção solar. De acordo com os critérios de validação analisados, os resultados do modelo numérico foram considerados calibrados e validados. Os resultados obtidos provam o potencial dos materiais de mudança de fase na regulação térmica e na otimização da eficiência energética dos espaços interiores dos edifícios.
The building sector is the largest final end-use consumer of energy in the European Union. The large energy consumption of the building sector is mainly resourcing to active systems for cooling and heating of indoor spaces. Presently, the external envelopes of offices and commercial buildings are systematically composed by large glazed areas, which lead to substantial heat losses through these zones. Thermal Energy Storage systems (TES), using phase change materials (PCM) in buildings, are widely investigated technologies and a fast developing research area. The use of phase change materials (PCMs) is presently an advanced solution to improve the energy performance of building components, namely the glazing and window shutter protections solutions. The present work presents and discusses a numerical and experimental testing of a thermal energy system that contains phase change materials. The testing apparatus is composed by two side-by-side compartments that have two similar windows shutters, one containing PCMs and the other considered as a reference solution, without PCMs. The internal compartments were submitted to similar weather conditions in a Mediterranean climate during the summer and winter season, and the south oriented facade is a glazed area that incorporates the window protection systems. According the used acceptance criteria, the results of the numerical model presented a good agreement and reliability and were considered calibrated with well prediction data. The results reveal the PCM potential for the thermal regulation of indoor spaces as well as improving the energy efficiency of indoor building spaces.
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Corsi, Maria. "Evaluation of the potential impact of electrochromic windows on the energy performance of commercial buildings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ54311.pdf.
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Rossman, Paula. "MISTRESS QUICKLY IN THE MERRY WIVES OF WINDSOR: A PERFORMANCE MONOGRAPH." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3579.
Full textAbstract:
The subject of my Thesis and accompanying Monograph Document in partial fulfillment of the requirements for the Master of Fine Arts degree / Performance Track is my work in the role of Mistress Quickly from William Shakespeare's The Merry Wives of Windsor. In my research, I will be focusing on a number of issues, many of which will bear direct relevance to and undoubtedly, more fully inform, my interpretation in performance. A key element of the performance-related side of my research will be an exploration of the cultural, historical, political, economic, and religious attributes of Shakespeare's times and how these factors drive Mistress Quickly's interactions with others, her perspectives of the society in which she lives, and her personal behavior. The directorial concept, as initially explained to the cast, will be keeping us within the English Renaissance and Shakespeare's time. Any variation within this initial concept will also be elaborated upon. Finally, I would like to explore the overall place of women at the time Shakespeare wrote, as well as during the specific time frame in which our production is set. Furthermore, I will look at Mistress Quickly as a character and how she is either reflected in or at odds with that societal placement.M.F.A.
Department of Theatre
Arts and Humanities
Theatre
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Li, Ma. "Essays on Mutual Funds and Fund Managers." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19361.
Full textAbstract:
Die vorliegende Dissertation besteht aus drei Kapiteln über die Investmentfonds. Das erste Kapitel befasst sich mit der Rolle der Fondsmanager in der Bilanzverschönerung. Auf Basis der Analyse der Karrierewege von amerikanischen Fondsmanagern werden signifikante zusammenwirkende Manager-Fixed-Effects identifiziert, die nach der Kontrolle der endogenen Matching-Probleme immer noch robust sind. Die geschätzten Manager-Fixed-Effects haben signifikante Einflüsse auf die Out-of-Sample-Vorhersagen. Außerdem wird festgestellt, dass die Verriegelungen der Investmentfonds, die von gemeinsamen Managern verwaltet wurden, wichtige Kanäle für die Bilanzverschönerung verursachen. Das zweite Kapitel beschäftigt sich mit den Investmentstrategien der Fonds im Hinblick auf die Nutzung von Credit Default Swaps (CDS). Die Zuordnung der CDS-Positionen der Investmentfonds zu ihrem Bestandportfolio bietet eine neue Methodik zur Identifizierung der CDS-Strategien und kompensiert somit die Analysen der existierenden Literatur auf der Makroebene. Die Ergebnisse zeigen, dass die Anreize zur Risikoreduzierung die Spekulationsanreize dominieren, insbesondere, wenn die Kreditexposition durch ungedeckte Leerverkäufe der CDS-Verträge erhöht wird. Die erfahrenen Fondsmanager tendieren dazu, mehr Kreditrisiko in Kauf zu nehmen, während es für die Fondsmanagerinnen wahrscheinlicher als für ihre männlichen Kollegen ist, gegen das bestehende Risiko abzusichern. Der letzte Teil nimmt die Pleite von Lehman Brothers unter die Lupe, um sich mit der daraus resultierenden unerwarteten Schließung der CDS-Positionen als einem natürlichen Experiment auseinanderzusetzten. Diese Studie dient zur Untersuchung der Risiko- und Leistungsimplikationen der CDS-Investments der Fonds. Die Investmentfonds besitzen bei ihren CDS-Transaktionen im Durchschnitt einen beachtlichen Teil Extremrisiko. Während die CDS-Nutzer von guten Gesamtmarktlagen profitieren, erleiden sie unter Verlusten bei geclusterten Ausfällen.This dissertation comprises of three chapters on mutual funds. The first chapter establishes the role of managers in the deceptive practice of window dressing. Employing comprehensive career history of U.S. mutual fund managers, I find strong jointly significant manager fixed effects, which are robust after addressing endogenous matching concerns. The estimated manager fixed effects are significant in making out-of-sample predictions. Further I establish that mutual fund interlocks through common managers are important channels that spread window dressing. The second chapter studies the investment strategies of mutual funds regarding their use of credit default swaps (CDS). Matches between mutual funds’ CDS positions and their underlying portfolio in the holdings facilitate a new approach in identifying CDS strategies that complements the “macro” level analyses in the existing literature. I find risk reducing incentives are dominated by speculative incentives, especially those to increase credit exposure via naked short CDS contracts. Experienced fund managers tend to take on more credit risk, while female managers are more likely to hedge comparing with their male peers. The third chapter employs the collapse of Lehman Brothers and the resulting sudden closures of CDS positions as a natural experiment to examine the risk and performance implications of mutual funds’ CDS investments. Funds on average load up on a significant amount of tail risk by trading CDS. While CDS users benefit when market conditions are favorable, they suffer during periods of clustered defaults.
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Greffet, Rémy. "Études expérimentale et numérique des performances énergétiques d'une fenêtre pariétodynamique." Thesis, La Rochelle, 2016. http://www.theses.fr/2016LAROS020/document.
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L'utilisation massive des énergies fossiles est en grande partie responsable des émissions de gaz à effet de serre. De plus, la croissance de la demande énergétique et la raréfaction des ressources fossiles conduisent à l'accroissement du coût de l'énergie. La réponse à cette problématique passe par deux moyens d'action indissociables : la réduction des consommations énergétiques et le recours aux énergies renouvelables. La fenêtre pariétodynamique permet d’agir sur les deux postes principaux de déperdition thermique d’un bâtiment que sont les baies et la ventilation. Le principe de la fenêtre pariétodynamique étudiée est de faire circuler de l’air en convection forcée entre trois verres avant d’être restitué à l’ambiance intérieure du bâtiment. Cela permet à l’air de récupérer à la fois une partie des déperditions thermiques à travers la fenêtre et une partie de l’énergie solaire absorbée par les verres. Afin d’étudier le comportement thermo-aéraulique et les performances de la fenêtre, nous avons développé un modèle numérique de cette dernière. Un dispositif expérimental a été mis en place et utilisé afin de valider le modèle numérique et de comparer en conditions réelles les performances de la fenêtre étudiée à celles d’une fenêtre à double vitrage classique. Ces résultats expérimentaux ont été complétés par une étude paramétrique numérique réalisée pour différentes conditions climatiques et de fonctionnement. Les principaux enseignements issus de ces études expérimentales et numériques sont que le préchauffage de l’air se fait essentiellement dans la lame d’air intérieure, la température de la première lame d’air restant proche de celle de l’air extérieur. De plus, et contrairement aux températures de la face intérieure et de l’air soufflé, celle de la face externe de la fenêtre est peu impactée par les paramètres étudiés. Concernant le cadre de la fenêtre, nous avons observé que celui-ci bénéficie aussi des échanges thermiques avec l’air circulant, mais dans une moindre mesure. Cela contribue à rendre la fenêtre peu déperditive. Enfin, en couplant le modèle développé à un logiciel de simulation thermique dynamique, nous avons évalué le potentiel d’intégration de fenêtres pariétodynamiques dans une maison individuelle. Nous mettons ainsi en évidence que le besoin de chauffage est réduit d'environ 20 à 30 % par l’utilisation de fenêtres pariétodynamiques à la place de fenêtres à double vitrage classique. En été, si l’ambiance intérieure du bâtiment est plus fraîche que l’environnement extérieur, la fenêtre pré-rafraîchit l’air neuf entrantThe massive use of fossil energies is largely responsible for greenhouse gas emissions. Moreover, the growth in energy demand and the depletion of fossil resources lead to an increase in energy costs. The response to this challenge requires two means of action which are linked : the reduction of energy consumption and the use of renewable energy. The airflow window acts on the two main ways of building heat losses that are windows and the ventilation. The principle of the studied airflow window is based on the circulation of fresh air, by forced convection, between the three glasses of the window before entering the building. This allows air to recover both a part of heat losses through the window and part of the solar energy absorbed by the glasses. To study the thermo-aeraulic behavior and thermal performances of the window, we have developed a numerical model of the studied airflow window. An experimental set up was used to validate the numerical model and compare, in real conditions, the studied window performances to the ones of a conventional double-glazed window. These experimental results were complemented by a numerical parametric study for different climatic and operating conditions.The main information from these experimental and numerical studies are that the preheating of the air takes place essentially in the inner air gap, temperature in the first air layer remaining close to the outdoor one. In addition, unlike the temperatures of the inside face and of the blown air, the outer face temperature of the window is not greatly affected by the studied parameters. On the window frame, we found that it also benefits of heat exchanges with the circulating air, but to a lesser extent. This makes the window energy efficient. Finally, by coupling the developed model to a thermal building simulation software, we evaluated the airflow windows integration potential in a house. We thus demonstrated that the heat load is reduced by about 20 to 30% by the use of airflow windows instead of conventional double-glazed windows. Moreover, in summer, when indoor is cooler than outdoor, we pointed out that the airflow window cools the incoming fresh air
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McDannald, Brandon K. "Performance Editions of Three Works for Winds by Gyorgy Druschetzky." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248398/.
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Gyorgy Druschetzky was a noted Czech composer of Harmoniemusik, who wrote more than 150 partitas and serenades, along with at least thirty-two other selections for larger wind groups. This is in addition to twenty-seven symphonies, eleven concertos (most for wind instruments), two fantasias, forty-seven string quartets, two operas, a ballet that is lost, and other miscellaneous chamber music for various combinations of wind/string instruments. Three of his works for winds have existed only in manuscript form since their composition: Concerto in E-flat pour 2 clarinett en B, 2 cors en E-flat, 2 fagott; Overture to Mozart's Die Zauberflöte; and Partitta a la camera a corno di bassetto primo, secondo, terzo, due corno di caccia, due fagotti. These works remain remarkably interesting to modern ears and deserve to be heard in the twenty-first century. Along with a brief examination of Druschetzky's life and how it figures into the history of Harmoniemusik, this work presents each piece edited into a modern performance edition.
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Yang, Shan-Chih, and 楊善智. "Improving TCP Performance by Utilizing Active Window Control Mechanism." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/27994975179737471193.
Full textAbstract:
碩士國立中正大學
電機工程研究所
89
Available bit rate (ABR) service is one kind of service that has been developed specifically to support data traffic over the ATM network. The source end system of an ABR connection transmits its data according to the rate informed by the ATM network to fairly utilize available bandwidth and minimize cell loss at the ATM layer. However, most data traffic today is connected to ATM networks via Ethernet. Simulation results show that as TCP traffic is carried over a path with concatenated Ethernet-ATM/ABR links, the packet queues are formed at the edge device interconnecting the Ethernet and the ATM network, instead of inside the ATM network. Furthermore, the edge device requires a buffer size equal to the sum of the receiver window sizes of all participating TCP connections. Two mechanisms are proposed to improve the TCP performance in such an environment - the BDP (bandwidth-delay product) -Aware mechanism and the active window control (AWC) mechanism. The AWC mechanism is the core of this thesis. It is proposed to reduce the buffer requirement and improve the TCP performance without changing the TCP protocol at the hosts. Through estimating the window size of the TCP source and modifying the window field in the TCP segment header skillfully, the edge device can control TCP sources actively. Simulation and experiment results show how the AWC improves the TCP performance.
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Lee, Hang-Ching, and 李漢卿. "Experimental Performance Analysis for Window Type Inverter Room Air-Conditioner." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/78hj6t.
Full textAbstract:
碩士國立臺北科技大學
冷凍空調工程系所
94
Application of inverter on air-conditioning equipments, such as water chillers, multi-type split air-conditioners…etc. is more and more popular globally. Due to building space restriction, split units and window units sold in the Taiwan market is around 50-50 share. In other words, demand for window units is still strong at this stage. Inverters are installed on split units in most of application as compared with window units. This study analyzes operation performance of window type inverter unit and traditional fixed frequency room air-conditioner. Tests for energy efficiency ratio (EER), power consumption and operation noise level by following CNS 3615 and CNS 14644 are performed in an environmental control test lab. Experimental results show that power consumption of inverter unit is 46% lower than fixed frequency unit. EER is higher (2.76 vs 2.38) but noise level is lower. It is estimated that energy saving can be achieved up to 46% during summer season if inverter unit is installed instead of fixed frequency one.
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Lee, Ivan Yun Tong. "High Performance Window Systems and their Effect on Perimeter Space Commercial Building Energy Performance." Thesis, 2010. http://hdl.handle.net/10012/5544.
Full textAbstract:
In the quest for improving building energy efficiency raising the level of performance of the building enclosure has become critical. As the thermal performance of the building enclosure improves so does the overall energy efficiency of the building. One key component in determining the energy performance of the building enclosure is windows. Windows have an integral role in determining the energy performance of a building by allowing light and heat from the sun to enter into a space. Energy efficient buildings take advantage of this free solar energy to help offset heating energy consumption and electric lighting loads. However, windows are traditionally the least insulating component of the modern building assembly. With excessive use, larger window areas can lead to greater occupant discomfort and energy consumption from greater night-time heat loss, higher peak and total cooling energy demand from unwanted solar gains, and discomfort glare. As a result, windows must be carefully designed to not only minimize heat loss, but also effectively control solar gains to maintain both a thermally and visually comfortable environment for the appropriate climate region and orientation. In this thesis, a complete analysis of window assemblies for commercial office buildings is presented. The analysis is divided into three sections: the Insulated Glazing Unit (IGU), the Curtain Wall Section (frames), and the overall energy performance of a typical office building. The first section investigates the performance characteristics of typical and high performance IGUs, specifically its insulating value (Ucg), its solar heat gain properties (Solar Heat Gain Coefficient, SHGC), and its visual transmittance (VT) through one-dimensional heat transfer and solar-optical modeling. Mechanisms of heat transfer across IGUs were investigated giving insight into the parameters that had the most significant effect on improving each performance characteristic. With a through understanding of IGU performance, attainable performance limits for each of property were generated from combining of different glazing materials, fill gases, and coatings. Through the right combination of materials IGU performance can be significantly altered. The U-value performance of IGUs ranges from 2.68 W/m2K (R-2.1) for a double-glazed, clear, air filled IGU to 0.27 W/m2K (R-21) for a quint-glazed, low-E, xenon filled high performance IGU. The second part of the thesis looks at the thermal performance of curtain wall sections that hold the IGU through two-dimensional heat transfer modeling. Similar to the IGUs, heat transfer mechanisms were studied to by substituting different materials to determine which components are crucial to thermal performance. From this analysis improvements were made to typical curtain wall design that significantly reduces the overall heat transfer within the frame section, producing a high performance curtain wall section. With simple modifications, a high performance curtain wall section can reduce its U-value by as much as 81% over a typical curtain wall section, going from 13.39 W/m2K to 2.57 W/m2K. Thus significantly reducing the U-value of curtain wall systems, particularly for smaller windows. The final part of the thesis examines the impact of typical and high performance windows on the energy performance of perimeter offices of a high-rise commercial building located in Southern Ontario. An hourly simulation model was set up to evaluate both the annual and peak energy consumption of a typical perimeter office space. The office faced the four cardinal directions of north, east, south, and west to evaluate the effect of orientation. The model also included continuous dimming lighting controls to make use of the available daylight. The effect of exterior shading on perimeter space energy performance was also investigated with both dynamic and static exterior shading devices. The results of the simulations revealed that window properties have very little influence on the energy performance of a high internal heat gain office, that is typical of older offices with less energy efficient office equipment and lighting and a higher occupant density. Conversely, window properties, particularly the insulating value of the window, has a greater effect on the energy performance of a mid to low internal heat gain office that is typical of most modern day commercial buildings. The results show windows with lower U-values yet higher SHGC are preferred over windows of similar U-values but with lower SHGC. The results also indicate that both static and dynamic shading have very little effect on energy performance of mid to low internal heat gain offices. From this analysis optimal window areas in the form of window-to-wall ratios (WWR) are presented for each orientation for mid to low internal heat gain offices. The optimal WWR for south-facing facades are between 0.50 to 0.66, and 0.30 to 0.50 for east-, west-, and north-facing facades, while for high internal heat gain perimeter spaces window areas should be kept to a minimum.
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Lin, Ping-Ju, and 林秉如. "A Study on Exhaust Performance of Smoke Ventilation Window Opening Variation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68880849499926159870.
Full textAbstract:
碩士國立臺灣科技大學
建築系
101
The main objective of this paper is to study the effects of exhaust performance for opening direction and angle of smoke ventilation window. By FDS (Fire Dynamics Simulator) and Zone model, simulation analysis is implemented to estimate mass flow rate; discharge coefficient and layer height. Comparisons between field model and zone model are rendered. The result shows that the overall mass flow rates of top hung window are less than those of bottom hung window and side hung window at the same angle of opening window. When the angle of opening window is less than , side hung window has a higher mass flow rate. However, bottom hung window has a higher mass flow rate when the angle of opening window is greater than . The ratios of mass flow rate for the angles of opening window to at top hung window; bottom hung window and side hung window are 73％; 80％ and 92％, respectively. For the angle of opening window , the discharge coefficient of bottom hung window is 0.717, which is greater than that of window without glass. The mass flow rates of effective opening less than those of three opening window types, the opening area identified of effective opening is obviously conservative.
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Tiwari, Vivek. "Performance enhancement in VANET with admission control and contention window adjustment." Thesis, 2012. http://hdl.handle.net/1828/4262.
Full textAbstract:
Vehicular Ad Hoc Networks (VANET), a derivative of mobile networks, has the
capability to increase the safety, e ciency and comfort of transportation systems,
and provide users on-the-road Internet connectivity. Because of its impetus and
signi cance in practical scenarios, it becomes a sought after topic in both industry and
academia. In this thesis, we focus on the vehicle-to-infrastructure (V2I) drive-thru
Internet services in a highway scenario. The road side unit (RSU) along a highway
can provide network services for vehicles within the coverage. To enhance the network
performance, we propose two strategies. First, to ensure a high network throughput,
the RSU uses an admission control strategy to limit the competition among vehicles,
and avoid the waste of channel time to the low-data-rate users. Second, based on
the vehicle density, we also propose a contention window (CW) adjustment strategy
which can reduce the collision probability when the network is congested, and reduce
the idle time otherwise. Extensive simulations using network simulator (NS-2) are
given, which demonstrate the e ectiveness of the proposed solutions.Graduate
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Chi, Wei-Cheng, and 紀威丞. "Double window layers engineering on the performance of HIT solar cells." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5441096%22.&searchmode=basic.
Full textAbstract:
碩士國立中興大學
電機工程學系所
107
Single and double window layers of p-type hydrogenated amorphous silicon (a-Si:H) films and p-type microcrystalline silicon (c-Si) with different band gaps (Eg), activity energy (Ea) and dark conductivity (d) were fabricated by modulated plasma power, pressure, hydrogen dilution, and RB2H6 (B2H6(1% in H2)/SiH4) ratio by plasma-enhanced chemical vapor deposition. The influence of different p-type a-Si:H and μc-Si:H films on the performance of HIT solar cells were investigated. The optical and electrical properties of the films were measured by Spectroscopic ellipsometer, and IV system. For the p-a-Si:H film, the increasing B2H6 flow rate reduces the bandgap and density but increases the dark conductance. For the p-μc-Si:H film, the fixing of doping gas ratio and the increasing the hydrogen dilution ratio increases the dark conductance and crystalline fraction. The fixing of hydrogen dilution ratio and the reducing doping gas increases the dark conductance and crystalline fraction, but reduces the density. Using p-a-Si:H to produce a single p-layer amorphous silicon HIT, the efficiency can reach to 7.26%. However, using p-uc-Si:H to produce a single p-layer microcrystalline silicon HIT, the efficiency is less than 1%. P-c -Si:H film is in contact with oxygen in the air, causing oxygen contamination of the film, resulting in lower open circuit voltage and the fill factor. For double-P layer HIT solar cell, depositing p-a-Si:H on p-μc-Si:H to avoid oxygen contamination of p-μc-Si:H, and p-μc-Si:H with high conductance increases the built-in potential. The double-P layer HIT solar cell fixes the total thickness of the P layer and increases the thickness of the p-μc-Si:H. Although p-μc-Si:H has a high dark conductivity, the film has high defect and lower density, which results in carrier recombination and reduced efficiency. The best HIT solar cell efficiency in this thesis is 8.38%
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Kuo, Yi-Chih, and 郭翼誌. "Double window layers on the performance of a-Si:H solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/03001214575224297591.
Full textAbstract:
碩士國立中興大學
光電工程研究所
103
In this thesis, various optical energy bandgap (Eg) of a-SiCx:H:By p-layers were combined to form single and double window layers for hydrogenated amorphous silicon (a-Si:H) p-i-n thin film solar cells, and its influence on the performance of solar cells were investigated. The Eg of a-SiCx:H:By p-layers were controlled by adding carbon atoms and reducing Si atoms in the layers. The first p-layer was connected with transparent conductive oxide (TCO) layer which was low Eg and named A-layer. The second p-layer was connected with i-layer which was high Eg and named B-layer. For combinations of Eg of p-layers were (1) modulation of Eg and thickness of A/B to form the equivalent Eg of 2.0 eV, (2) reduction thickness of B-layer to ultra thin of 5 Å, (3) fixed thickness ratio of 75 Å/25 Å, change Eg ratio of A/B, and (4) fixed Eg of A/B to 1.7 eV/2.1 eV, change thickness ratio of A/B. Using these four combinations of double p-layer window layers to investigate the influence on the efficiency of solar cells. The results of (1) shown that as the Eg of B-layer larger than 2.5 eV, more photons could penetrate into i-layer to increase the short-circuit current density (Jsc). However, the film was more defects to significantly reduce the fill factor (FF) and open-circuit voltage (Voc). The efficiency of solar cell was significantly reduced. The results of (2) demonstrated that reduction of thickness of high Eg of B-layer (> 2.5 eV) could reduce the decreasing of FF and Voc. The results of (3) indicated that low Eg of A-layer could improve FF, and the low defect of high Eg of B-layer should be used. In this study, the best Eg ratio of A/B was 1.7 eV/2.1 eV. The results of (3) shown that increase thickness of A-layer and decrease thickness of B-layer could result in reduction of Jsc and Voc but increase of FF. There was an optimization of thickness ratio of A/B layers. For this study, the highest efficiency cell was 1.7(25 Å)/2.1(75 Å) double window layer, the Jsc, Voc, FF and was 12.10 mA/cm2, 0.83 V, 63.31% and 6.33%, respectively.