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Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Lic.-avh. Linköping : Linköpings universitet, 2005. / På titelsidan felaktiga serieuppgifter.

Examensarbete.

Thesis submitted in fulfilment of the requirements for the award of the Degree of Doctor of Philosophy in the Department of Library and Information Science at the University of Zululand, South Africa, 2012. / The purpose of this study was to investigate the diffusion of information and communication technologies (ICTs) in the informal sector in Kenya. The study specifically focused on micro and small enterprises (MSEs) in two provinces in Kenya, namely Nairobi Province and Central Province. Information for the study was gathered through a literature review, a field survey, and personal observation. Questionnaires were used to solicit information from micro and small enterprise participants drawn from the two provinces. A combination of purposive and probability random sampling was used to generate the sample frames of MSE clusters and respondents respectively. The sample of respondents was drawn from the central business district in the city of Nairobi, two markets (Gikomba market and Kenyatta market) and a horticultural products’ depot next to Jomo Kenyatta International Airport in Nairobi Province. Two urban centers and two market centers were selected from Central Province, namely Kiambu and Thika towns and Kabati and Makutano market centers in Muranga District. Questionnaires were administered to a sample of 390 MSE participants comprising of owner/managers and selected employees. The overall results revealed that the majority of MSEs are small and are started with little preparation and scarce capital. Only 5.6% of the enterprises had more than five employees, while less than one percent had over ten employees. The majority of the MSEs (over 90%) therefore fell in the micro-enterprises category. The use of ICTs by the micro enterprises’ participants, with the exception of the mobile phone and mobile money services, was found to be quite low. The use of the mobile phone and mobile phone services was over 90%. . Access to formal business information sources was also poor, and the majority of the MSE participants relied mainly on their knowledge and experiences, customer reactions, telephone contacts, and friends and relatives. Information was rarely sourced from government agencies and other formal sources like the internet and mass media. MSEs face many challenges in the use of ICTs because of the nature and small scale of their businesses, which do not allow them to focus on much else beyond survival. The MSEs lacked institutional capacity and support in the form of affordable telecommunications facilities and ICTs as formal sources of information. The mobile phone has been embraced by MSE workers, as an affordable and quick way to communicate and perform business transactions. The mobile phone technology has been quickly adopted and is heavily relied on in MSE operations. The study recommends accelerated government involvement in order to address the various challenges of providing the necessary infrastructure, developing and implementing effective policies, improving the distribution of economic resources, improving business premises and infrastructure that can reach the MSEs, improving skills and training to enable the use of ICTs, raising awareness, facilitating access to credit and finance, as well as improving information structures for formal information sources and dissemination. The study recommends more research to gain a deeper understanding of the context and information needs of small business enterprises in order to be able to offer a strategic framework for appropriate intervention in providing information for MSEs. Further research is also recommended in the area of mobile telephony, given its rapid adoption and use in a short span of ten years, to bring out its full potential and benefits. / University of Zululand

Information diffusion is significant in fields such as propagation prediction and influence maximization, with applications in viral marketing and rumor control. Despite conceptual differences, existing diffusion models may not represent identical underlying generative structures. A classification of diffusion of information models is developed based on infection requirements and stochasticity. The study involves analyzing seven existing DOI models on directed scale-free networks. The distinctive properties of each model are identified through simulations and analysis of experimental results. Our analysis reveals that similarity in conceptual design does not imply similarity in behavior concerning speed, the final state of nodes and edges, and sensitivity to parameters. Therefore, we highlight the importance of considering the unique behavioral characteristics of each model when selecting a suitable information diffusion model for a particular application. We further investigate how the network structure and clustering affect the diffusion of information. Our findings reveal that clustering does not consistently accelerate the spread of information. Instead, the extent to which clustering facilitates the dissemination of information is influenced by the interplay between the specific network structure types and the information diffusion model employed. Another significant aspect of information diffusion is the effect of influential nodes. Identifying highly influential nodes is of great interest for strategic targeting in various applications such as viral marketing and information campaigns. Our follow-up study aims to identify influential nodes using a transfer entropy-based method. In this work, we use our method to identify influential users in Twitter data and compare the results against other existing methods. Finally, we developed a methodology based on Transfer Entropy to evaluate influence in the context of information diffusion. This methodology demonstrated its superiority in predicting user adoption against retweet-based metrics, marking it as a direct and reliable metric for understanding influential users and information diffusion trends.

Diss. Linköping : Univ., 2002.

African Americans as a group tend to have numerous health issues, and by the time they seek healthcare, the conditions often advance into more serious ailments. Researchers have shown that cultural distrust of the U.S. healthcare system coupled with some discriminatory practices has hindered African Americans seeking care and taking full advantage of the healthcare system. With the introduction of the Patient Protection and Affordable Care Act (ACA), there is some confusion about the application of the law, resulting in many intended beneficiaries misinterpreting it, and not accessing quality healthcare. This interpretive phenomenological study explored how African Americans in the Washington D.C., metropolitan area understand and interpret ACA provisions related to their healthcare needs. A sample of 10 African Americans adults participated in in-depth interviews that generated data for this study. Critical communicative methodology provided a framework for exploring the phenomenon. Study findings highlight the themes of interpreting the ACA to mean having more individual control and responsibility for healthcare decisions and having fewer perceived restrictions acting as barriers to access healthcare. Study results contribute to social change by providing knowledge to those who implement healthcare policy on optimal policy delivery to intended beneficiaries. This knowledge may also apply to other new social policy dissemination, thus ensuring policies reach their intended target populations, facilitating optimal utilization.

The visualization of a 3D image obtained from computerized tomography examinations has shown itself to be an important factor for increasing the quality of medical diagnoses and, consequently, treatment efficacy. There already exist on the market, several visualization softwares, which use different techniques to show the 3D tomography image. However, to show a high quality 3D image, sophisticated devices must be used to obtain slices, close to one another, thus increasing the incidence of X-ray given to the patient. An interpolation slice method which resulted from the TC examination produces good results, and is able to reduce the X-ray incidence upon the patient. This method must reconstruct the curvature from the patient s internal structures without using slices in close proximity. This work proposes a method of 3D image interpolation, composed of a juxtaposition of the slices from CT examination results. The goal of this method is to increase the quality of 3D visualization through the production of sharp and precise structure contours. This thesis proposes the division of the interpolation method into two steps. In the first step, the goal is to obtain an initial representation of the image in 3D, which is composed of real slices as well as virtual slices which are referred to in this work as initial virtual slices. In the second step, the empty spaces of the structure are recovered by the 3D image inpainting process. This work also proposes a method to obtain the initial virtual slice and two different methods for inpainting the 3D image. These inpainting methods are the transversal slice line prolongation method and the transportation and diffusion of information. Both methods use the differential equation theory. The transportation and diffusion of information method shows better results than other methods proposed in this work, besides this, this method presents better results than the linear interpolation and Goshtasby et al. [1] methods also implemented in this work. Visual and numerical comparisons are used to obtain this conclusion. The numerical measures used are statistical correlation, the PSNR and the Hausdorff distance [2]. The transportation and diffusion of information method shows itself able to produce better results than all the other tested methods. Besides this principal contribution, this work also developed a KIT to implement 2D and 3D CT visualize applications. / A visualização de imagens resultantes de exame de tomografia computadorizada (TC) em 3D ´e um fator importante para o aumento da precisão nos diagnósticos médicos e, consequentemente, na eficácia dos tratamentos. Atualmente existem diversos produtos no mercado, que fazem uso de várias técnicas existentes para apresentação de imagens tomográficas em 3D. Contudo, para se obter maior suavidade e precisão nos contornos das estruturas visualizadas em 3D, utiliza-se equipamentos capazes de produzir fatias paralelas do corpo humano muito próximas uma das outras, aumentando a exposição dos pacientes aos raios X. Um método de interpolação de fatias resultantes de exame de TC que forneça bons resultados, pode reduzir a incidência de raios X no paciente, pois esse método pode recuperar a curvatura das estruturas sem a necessidade de uma grande proximidade entre as fatias. Este trabalho propõe um método para a interpolação de imagem em 3D, formada pela justaposição de fatias de resultados de exames de tomografia computadorizada. O objetivo desse método ´e obter contornos suaves e precisos, melhorando os processos de visualização em 3D. Para isso, esta tese propõe a divisão do processo de interpolação em duas etapas. Na primeira etapa obtém-se uma representação inicial da imagem em 3D composta por fatias reais e por fatias denominadas de fatias virtuais iniciais e, na segunda etapa, restaura-se essas estruturas geradas com um processo de retoque de imagem em 3D. Este trabalho propõe também um método para obtenção da fatia virtual inicial e dois métodos diferentes para a realização do passo de retoque da imagem em 3D resultante da justaposição das fatias reais e virtuais iniciais. Esses métodos são o prolongamento de linhas nas fatias transversais e transporte e difusão de informações. Ambos os métodos utilizam a teoria de equações diferenciais. O método de transporte e difusão de informações demonstrou melhores resultados do que outro método proposto neste trabalho, além de obter melhores resultados do que os métodos de interpolação linear e Goshtasby e outros [1] implementados neste trabalho. Comparações visuais e comparações numéricas utilizando a correlação estatística, a PSNR e a distância de Haussdorff [2] foram realizadas para se obter essas conclusões. O método de transporte e difusão de informações é capaz de gerar contornos mais suaves e precisos que esses outros métodos testados. Além dessa contribuição principal, este trabalho também desenvolveu um KIT para a construção de aplicações visualizadoras de tomografias computadorizadas em 2D e em 3D. / Mestre em Ciências