Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 179-191). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 179-191). Also available on the Internet.

M. S.

The working hypothesis underlying this research was that computerized electronic marketing influences price level and the price discovery process. Electronic markets were also hypothesized to alter bidding strategies of participants. The theoretical background which stimulated this study arose from the shortcomings of the competitive market system in agriculture. One possible solution to agriculture's pricing problems is electronic markets. Solving the thin market problem through increased participation via electronic markets can help to increase prices. Three types of buyers use ELPC's system: packers, order buyers, and local buyers. Larger buyers are more disciplined buyers. They bid less, pay lower prices, and obtain a higher percentage of lambs sold. Large buyers have different objectives than smaller local buyers and are under more economic pressure to stay abreast of market conditions. Electronic markets are unique since they set bid wait time intervals and identities of bidders remain anonymous. Both the bid wait time interval and the anonymity feature significantly influence improvements in price during the auction process. Bid wait time intervals are necessary in developing electronic markets. Finding the optimum interval (9 to 12 seconds) will aid in setting bid increments for new electronic markets. Bidders, with anonymous bidding, will bid for longer periods of time and this means higher prices. This important finding suggests that overt or tacit collusion, which could occur in conventional auctions, does not occur in the computerized sales with the anonymous bidding. / M.S.

This master thesis is exploring Beekeepers usage of Internet of Things, or “Internet of Bees”. Since most of the prior contributions are focusing on data gathering, the approach to focus on the users needs is central to take next steps in the field of using IoT for Beekeeping. After the introduction a chapter with an overview of current research and commercial solutions are presented. This is followed by a quantitative study with 222 responds, answering what beekeepers like to know about their bees, what platforms used by end users and what the beekeeper as a user expects. An demo of an existing commercial system is set up in real conditions, describing how to mount and configure a demo. Communication, synchronization and presentation is described. A closed user interface and a public user interface are a part of the demonstration. Potential users of this technique are interviewed to gain better understanding of users opinion of the demo. This is followed by another demo using a free of charge app where sound analysis processed with AI is tested. This thesis explains what beekeepers as users of Internet of Things could gain added value to their beekeeping.

Orientador: José Antonio Siqueira Dias / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-22T06:29:21Z (GMT). No. of bitstreams: 1 Roque_Wellington_D.pdf: 36135434 bytes, checksum: 2e9ca0be59b1286da36d45ebc67dfd0d (MD5) Previous issue date: 2012 / Resumo: A aplicação de sensores de umidade do solo vem aumentando devido à necessidade do uso eficiente da água para irrigação. Uma das técnicas amplamente utilizadas para o desenvolvimento desses sensores é a de dissipação de calor. Nesta técnica, um elemento aquecedor é usado para aplicar um pulso de calor no solo, gerando um aumento de temperatura, o qual é mensurado e relacionado com a umidade do solo. Porém, um dos principais problemas desse tipo de sensor é sua baixa sensibilidade. Buscando resolver esse problema, foi desenvolvido um sensor que utiliza um transistor bipolar como único elemento aquecedor e transdutor de temperatura. Uma energia aplicada causa aquecimento no transistor e consequentemente provoca uma variação na tensão da junção base-emissor. Com isso, realizamos um estudo, a fim de determinar qual o valor ideal de energia aplicada que proporcionaria a máxima sensibilidade na medida da variação da temperatura. Para isso foram utilizados para fabricação dos sensores 16 transistores com encapsulamento metálico (TO - 18). Os sensores foram inseridos em amostras de solo deformadas, que foram saturadas para realização da medida da umidade do solo, através do método gravimétrico. Foram realizados com cada sensor curvas de calibração relacionando a umidade do solo com a com o valor de ?T, para os diferentes valores de energias fornecidos no sensor. Após análise dos dados, foram escolhidos dois sensores que apresentaram maior variação entre suas curvas de calibração para serem inseridos em uma solução de Agar Agar e no Ar, realizando várias medidas nos sensores, sempre com os mesmos valores de energia, para verificar a repetibilidade dos mesmos. Os resultados mostraram que, em relação à energia aplicada no sensor, àquela que proporcionou uma maior sensibilidade em função da umidade do solo foi de 1:5J (25 V, 6,3 mA, 10 s). Foi constatado que a sensibilidade do sensor melhora com o aumento da potência, sendo que esta melhora é relativamente independente da energia fornecida. Em relação às medidas realizadas no Agar Agar, observamos uma melhora considerável do erro em função das medidas realizadas no solo, de 10% para o solo, para 4% no Agar Agar. Para as medidas realizadas no Ar, o valor do erro diminui para 1%. Para as medidas realizadas no solo, na solução de Agar Agar e no Ar, chegamos à conclusão que a diminuição do erro das medidas realizadas em cada um deles, ocorre devido à mudança do contato do sensor com o solo durante as medidas, visto que o solo, quando começa perder umidade ele altera o seu volume, levando a uma diminuição da superfície de contato do mesmo com o sensor. Esse erro pode ser também em função da variação da densidade do solo que ocorre durante a realização dos ensaios, causando uma diferença no valor das medidas, já citadas em outras literaturas. Observamos também que para a melhor utilização do sensor em diferentes faixas de umidade do solo, há a necessidade de alterar a energia aplicada, devido à sensibilidade de o sensor ser maior para umidades mais baixas (abaixo de 30%), necessitando de um acréscimo do valor da energia aplicada para se obter uma melhor sensibilidade para umidades altas (acima de 30%) / Abstract: The use of soil moisture sensors is increasing due to the need for efficient use of water for irrigation. One technique widely used for the development of these sensors is the heat dissipation. In this technique, a heater element is used for applying a pulse of heat into the soil, causing a rise in temperature, which is measured and related to the soil moisture. However, a major problem of this type of sensor is its low sensitivity. To solve this problem, we developed a sensor that uses a bipolar transistor as a single element heater and temperature transducer. Energy applied to the transistor causes its heating, which in turn causes a variation on the voltage of the base-emitter junction. So we conducted a study to determine the optimal value of energy applied to provide maximum sensitivity in the measurement of temperature variation. To do this, 16 metal case TO-18 package transistors were used in the fabrication of the sensors. The sensors were inserted in deformed soil samples, which were water-saturated to perform the measurement of soil moisture using the gravimetric method. With each sensor we obtained calibration curves relating the soil moisture to the value of temperature for the different values of energy supplied to the sensor. After analyzing the data, two sensors that showed greater temperature variation in their calibration curves were chosen to be inserted into a solution of Agar Agar and in the air, in order to perform multiple measurements with the sensors at the same energy values to check their repeatability. The results showed that the energy which provided a greater sensitivity as a function of soil moisture was 1,5 J (25 V, 6,3 mA 10 s). We have found that the sensor sensitivity improves with increasing dissipated power and this improvement is relatively independent of the energy supplied. Regarding the measurements performed in Agar Agar, we observed a significantly lower error compared to the measurements taken in the soil: from 10% for the soil measurements to 4% in the Agar Agar. For the measurements made in air, the error decreased to 1%. For the measurements made in soil, in solution of Agar Agar and in air, we concluded that the decrease of the measurements errors performed in each of them occurs due to a changing in the contact between the sensor and the media during the measurements, because the soil changes its volume when it begins to lose moisture, leading to a decreased surface contact with the sensor. This error can also be due to the variation of soil density that occurs during the tests. We also observed that for the best use of this sensor in different ranges of soil moisture there is a need to change the applied power due to the higher sensitivity of the sensor for moisture content below 30%, needing an increase in the amount of this power to obtain a better sensitivity to humidity above 30% / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica