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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Pluecker Coordinates of Lines Determined by Permuting the Projective Coordinates of a Point

Gross, Ferd W. January 1939 (has links)
No description available.
72

Pluecker Coordinates of Lines Determined by Permuting the Projective Coordinates of a Point

Gross, Ferd W. January 1939 (has links)
No description available.
73

On-line služby v nemocnicích / On-line Services in Hospitals

Venkrbcová, Eva January 2015 (has links)
The thesis is focused on mapping of selected on-line services in hospitals in Czech Re-public according to their availability. In the next step logistic regression model will be used, which will measure a range of particular on-line services according to their legal form, majority ownership, region in which health organization is located, to education achieved and gender of hospital director and lastly in accordance with the size of hospital from the viewpoint of bed capacity. This thesis will provide comprehensive overview of availability of on-line services in Czech hospitals and determine which factors significantly decreasing or increasing chance of their occurrence on hospital websites.
74

ESTIMATION OF TRANSMISSION LINE PARAMETERS USING LINEAR METHOD WITH SYNCHRONIZED AND UNSYNCHRONIZED DATA

Lahmar, Mustafa 01 January 2019 (has links)
Accurate value of transmission line parameters is important for power system protection applications, especially for distance relays whose zone settings are based on positive sequence line impedance. The research is devoted to estimating transmission line positive-sequence parameters from synchronized or unsynchronized measurements of voltage and current phasors that are obtained at both terminals of the line. The positive sequence parameters including series impedance and shunt admittance can be linearly estimated. The linear least square algorithm has been derived in this dissertation for different transmission line configurations. The algorithm is able to handle both synchronized and unsynchronized measurements and deal with potential synchronization errors by explicitly modeling the synchronization angle. Sample results are reported to demonstrate the effectiveness of the proposed method. Three types of transmission line models depending on line length (long, medium and short) are studied in this dissertation. Chapter 3 uses unsynchronized data for the long transmission line. The derived method can detect the unsynchronized angle and estimate the positive sequence of long line parameters. The proposed method is examined with negative impacts such as errors on currents and voltages data. These errors are added randomly to one set each time to test the robustness of the developed algorithm. The medium transmission line algorithm derivation is presented in chapter 4. This chapter uses a linear least square to estimate the lumped parameters of a medium transmission line. The two different transmission line circuits are used to model the medium line. The first circuit is a single transmission line with two nodes and is used to evaluate the developed algorithm. The second circuit is a double transmission line. These two lines can have the same or different line parameters or line length. The developed algorithm shows that the proposed method achieves highly accurate results for the estimation of positive sequence line parameters. The short transmission line is studied in chapter 5. The short transmission line uses less data than the long or medium lines because in this model the shunt capacitance is omitted. Thus, the linear estimation yields highly accurate results. Case studies are considered to test the robustness of this developed method. The line temperature mainly affects the series resistance, and the developed algorithms in previous three chapters can accurately estimate the transmission line parameters. To simplify the real-time estimation of line resistance and temperature, the series inductance, and shunt capacitance can be treated as constant and known values. Chapter 6 provides such studies of estimating resistance by treating inductance and capacitance as known values.
75

Synchrophasor based method for computing the Thevenin equivalent impedance seen by a concentrated wind farm region

Kowley, Puja Ajay 04 November 2010 (has links)
Transmission line reactance is an important parameter in carrying out stability studies. The model proposed here utilizes available real time synchrophasor data and information about the generation in the ERCOT grid to determine the Thevenin equivalent reactance of a line. Synchrophasors provide the advantage of synchronized measurements of phase angles which are essential in determining the transmission line reactance. This thesis provides the results of applying this model to estimate the Thevenin equivalent line reactance between McDonald Observatory in West Texas and The University of Texas at Austin. / text
76

Atitudes em relação a sites de leilão on-line: um estudo exploratório com internautas brasileiros / Attitudes towards on-line auctions: a study with brazilians internet users.

Donega, Ricardo Angelotti 30 September 2004 (has links)
O objetivo do presente estudo é identificar as possíveis dimensões que formam a atitude do internauta em relação aos sites de leilão on-line, por meio da aplicação de um instrumento de coleta de dados e posterior avaliação da atitude global. Inicialmente são apresentados os conceitos referentes a atitude sobre uma perspectiva histórica e, os modelos estruturais mais conhecidos e as formas mais utilizadas para se avaliar as atitudes. São apresentados também os conceitos referentes ao comércio eletrônico com foco no modelo de leilões on-line. É desenvolvida uma escala para se medir atitudes, com base tanto na literatura encontrada como por meio de entrevistas com usuários do site. Para se analisar e validar a escala, é feita uma pesquisa exploratória com mais de quinhentos internautas onde por meio do uso de análise fatorial, chega-se a um modelo onde à atitude global foi avaliada. / The aim of this research paper is to identify the dimension of internauts? attitudes towards online auctions? websites through a questionnaire application for data collecting and posterior evaluation of global attitude. This paper presents at first some attitude concepts from a historical perspective, the most known structural models and the most used ways for attitude evaluating. Some concepts about eletronic commerce, focusing on online actions are also discussed. Then a scale was developed based on the literature review and in interviews made with the website?s users, in order to measure attitudes. With the purpose of analyzing and validating the scale an exploratory research was done with more than five hundred internauts and using factorial analysis a model where the global attitude was evaluated has been constructed.
77

Comportamento do consumidor e a compra on-line: uma análise multicultural / Consumer behavior and purchase on-line: a multicultural analysis

Caro, Abrão 07 April 2010 (has links)
Apesar de todo o crescimento apresentado, o comércio eletrônico está apenas iniciando. As diferenças entre as lojas virtuais e as lojas físicas além das estratégias inovadoras de marketing neste novo ambiente devem estar mudando hábitos e estilos de compra. Não obstante às novas opções e formas para comprar que o consumidor passou a ter, muito pouco se sabe sobre as mudanças em relação às suas atitudes, percepções, adoção ou não da compra virtual. Este foi o elemento direcionador deste trabalho que procura analisar as inter-relações entre a inovatividade e o envolvimento, fatores que se apresentaram como preditores da adoção da internet em estudos anteriores, a atitude dentro do modelo TPB (Theory of Planned Behavior) decomposto desenvolvido, na Psicologia Social com o processo de adoção da compra pela internet. Considera-se a Cultura como fator moderador, comparando-se os resultados com países de culturas diferentes a partir das dimensões de Hofstede. Com este propósito foi elaborado um modelo integrativo considerando os estudos desenvolvidos sobre os fatores apontados e que possibilitasse explicar a relação entre estes fatores e a compra pela internet dentro de um contexto de diferenciação cultural de consumidores de diferentes países. O trabalho envolveu uma pesquisa de campo considerando uma amostra não probabilística internacional de estudantes de grupos de países com grandes diferenças nas dimensões culturais, possibilitando assim, destacar a influência da cultura na relação entre inovatividade, envolvimento, atitude e experiência com a internet e a adoção da compra pela internet. O procedimento de coleta envolveu o desenvolvimento de um site contendo um questionário com auto preenchimento pela internet. Para poder ser entendido pelos respondentes, o questionário é apresentado nos idiomas: português, inglês, francês, espanhol e alemão. Para a análise dos resultados foi utilizado o método multivariado de modelagem de equações estruturais, aplicado por meio da técnica PLS (Partial Least Squares) para a verificação, explicação e comparação das relações entre os construtos. Os resultados mostram que a intenção da compra pela internet é diretamente influenciada pela atitude como fator interno e pela pressão social como fator externo. Apresenta também a influência indireta do envolvimento. A relação entre os fatores intenção e compra, assim como, envolvimento e atitude é mais forte nos países com mais igualdade entre seus membros e mais individualistas, enquanto a influência dos fatores inovatividade e condições facilitadoras se apresentou mais forte nas sociedades mais coletivistas que nas mais individualistas. As sociedades mais voltadas para a realização e a aquisição de dinheiro e posses materiais apresentaram maior influência de fatores sociais na intenção de adotar a compra pela internet que as culturas com maior preocupação com com a qualidade de vida e com o meio ambiente. As culturas com menor aversão ao risco mostraram uma relação mais forte entre o envolvimento e a atitude que as mais aversas ao risco enquanto para estas últimas a influência social é mais forte na adoção da compra pela internet. Estes resultados podem ajudar no desenvolvimento de estratégias de marketing num ambiente em que as barreiras internacionais parecem estar estão diminuindo e as empresas buscam estar presentes em diferentes países por meio do marketing global. / Although all the presented growth, the electronic commerce is only initiating. The differences between the virtual store and the physical store beyond the innovative strategies of marketing in this new environment must be changing habits and styles of purchase. Not obstante the new options and forms to buy that the consumer started to have, much little is known on the changes in relation to its attitudes, perceptions, adoption or not of the virtual purchase. This was the driving element of this work that it looks to analyze the relations between the innovativity and the involvement, factors that if had presented as predictors of the adoption of the Internet in previous studies, the attitude inside of model TPB (Theory of Planned Behavior) decomposed developed in Social Psychology, with the process of adoption of the purchase by the Internet. The Culture is considered as factor moderator, comparing the results between countries of different cultures from the dimensions of Hofstede. With this intention an integrated model was elaborated considering the studies developed on the pointed factors and that it made possible to explain the relation between these factors and the purchase on line. The work involved a field research considering an international not probabilistic sample composed by students from groups of countries with great differences in the cultural dimensions, thus making possible, to detach the influence of the culture in the relation between innovativity, involvement, attitude and experience with the internet and the adoption of the purchase on line. The data collected procedure involved the development of a site contends a questionnaire with auto fulfilling by internet. To be able to be understood by the respondents, the questionnaire is presented in the languages: Portuguese, English, French, Spanish and German. For the analysis of the results the technique used was multivaried statistics of structural equations modeling applied by means of the program PLS (Partial Least Squares) for the verification, explanation and comparison of the relations between the constructs. The results show that the intention of the purchase on line is diectly influenced by the attitude as internal factor and the social pressure as external factor. It also presents the indirect influence of the involvement. The relation between the factors intention and involvement, as well as, involvement and purchase on line is stronger in the countries with more equality between its members and more individualistic. Societies that have tendency to the acquisition of money and goods. had presented greater influence of social factors in the adoption of the purchase by internet than the cultures with bigger concern with the quality of life and the environment. The cultures with less aversion to the risk had shown a stronger relation between the involvement and the attitude to buy on line than the societies with more aversion to the risk, while for this last the social influence is stronger in the adoption of the purchase on line. These results can help in the development of programs of marketing in an environment where the barriers are diminishing and the companies search to be gifts in different countries.
78

Integrated On-Line and Off-Line Electronic Cash

Liao, Tsai-hsiu 06 September 2007 (has links)
Due to ubiquity of internet, the development of electronic commerce is growing up rapidly. Many payment mechanisms of electronic transactions are proposed, such as electronic cash, credit cards, and electronic wallets. Electronic cash (e-cash) is like the digital version of paper cash, which possesses some key features such as anonymity and untraceability, and it can be used on the Internet for various electronic transactions. In general, electronic cash is classified into two types which are on-line electronic cash and off-line electronic cash. Each of them is suitable for different applications and environments. All of the proposed electronic cash schemes only focus on one of two types. In these schemes, users must decide which type of electronic cash they will use later before withdrawing. However, in this thesis we propose a novel electronic cash scheme which supports a user to withdraw a generic e-cash and then decide to spend it as an on-line e-cash or an off-line e-cash. Our proposed scheme is more convenient for users and more flexible for the bank and shops. It not only satisfies the necessary properties of electronic cash but also provides flexibility.
79

創新生意模式 – 案例分析 LINE / New Business Models of Innovation – Case study of LINE

李儒婷, Lee, Sabrina Unknown Date (has links)
創新生意模式 – 案例分析 LINE / As more people around the world start using smartphones, instant-messaging apps are emerging not only as an alternative to conventional mobile text-messaging, but also as a social network that could replace some of the roles played by Facebook Twitter and others. One of the fastest-growing messaging apps in the world is LINE, developed and operated by Tokyo-based LINE Corp. Just over the past year, LINE has seen the number of its users surge nearly fourfold to more than 500 million. In this paper, we will discuss the reason why LINE become so popular, and how is it new business model work. The main reason LINE become so successful is that LINE grasp the essential needs of users and it also look deeply insight the market. Each function LINE had was not innovative at that time, just like games, photo-sharing, and a Facebook-like home page and timeline, however a lot of people would find it convenient if one app can let them experience many different things, then it combine all the function to become a successful LINE. It also created a new way to communicate for boring text message. It create its virtual stickers often featuring cute and quirky cartoon characters that people can send as messages which change users communicate behavior to use stickers instead of text. By these cute character it also create new business model. The company’s revenue comes from the sales of virtual stickers as well as virtual items sold in games. Also generate with game title, which design with LINE character. The app also makes money by charging businesses that use official Line accounts to distribute promotional messages. In the future, LINE's ambition is to becoming a broader platform for social network and entertainment. The communication app category is crowded and competitive; therefore the company has to create its irreplaceable value to stand stable in this number one position.
80

On-line networks, social capital and social integration: a case study of on-line communities in Malaysia.

Wan Jaafar, Wan Munira January 2011 (has links)
In 1996, Malaysia developed a national ICT policy intending to establish on-line community networks amongst all citizens as part of the agenda to prepare the nation to become a mainstream knowledge-based society and economy. As a country that has historically experienced uneasy tension between inter-ethnic social relationships, this research seeks to explore whether on-line social networking affects the forms of social capital and social integration found amongst diverse on-line ethnic communities (Malay, Chinese and Indian) in Malaysia. Six on-line communities were selected as case studies and the research was carried out in two stages. The first stage involved interviewing three different groups of participants: on-line community administrators, Government representatives and the general public; the second stage was a web-based survey of on-line participants. The findings suggest that the six selected on-line communities in this study show great potential for enhancing social networks and social capital across all members of different ethnicities. However, these are not significant enough to create social integration across all ethnic communities. Instead, three different trends of bonding and bridging social capital emerged across the six selected on-line communities. The first trend shows bridging social capital throughout both on-line and off-line activities in MalaysiaMAYA.com (social networking site), SARA (residential-based) and FamilyPlace.com (parenting and children). The second trend indicates that bridging networks were limited to on-line communication as seen in both residentially-based communities (USJ Subang Jaya and PJNet). In contrast, VirtualFriends.net (social networking site) only demonstrates bonding social capital developed in both on-line and off-line social networking. Considering these diverse patterns, it is argued that transferring bridging social capital from an on-line medium to an off-line medium is challenging. Factors of cultural capital such as language use and cultural and religious observations have been highlighted as significant in shaping community networking patterns. Overall, the issue of ethnic integration in the context of on-line communities in Malaysia remains, at best, a challenging factor for the formation of on-line/ off-line social capital.

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