211 |
MARKETING IN THE AGRICULTURAL ECONOMIC DEVELOPMENT OF KORDOFAN, SUDAN.SPEECE, MARK WILLIAM. January 1987 (has links)
Although Sudan is a country with enormous agricultural potential, agriculture has not prospered over the last two decades and Sudan now finds itself a bankrupt net importer of food. Much of the country's agricultural resource base is found in the rainfed agricultural region of Western Sudan, which includes Kordofan. This study focuses on Kordofan, and reports on data gathered during work for the Western Sudan Agricultural Research Project. Rather than following the production orientation usually employed by economists, it addresses issues related to the role of marketing in agricultural economic development. Marketing in Kordofan, as well as production, is subject to disruption because of climatic variations characteristic of arid and semi-arid regions. Extended annual dry periods and droughts distort price performance for agricultural commodities and cause shifts in marketing channel structure. Risk levels are substantially increased for producers and small traders, while at the same time they must take on increased responsibility for many channel functions. Marketing also suffers from infrastructure deficiencies: roads are often impassable during the rainy season, and storage losses become huge over the course of a year. The private marketing system in Kordofan has adapted to these conditions, and is performing quite effectively, efficiently, and equitably, given the adverse conditions. Competition is extensive, farmers have many alternatives when selling crops, and merchants operate on fairly modest profit margins. A widespread bias against the private sector has led to extensive government intervention into marketing spheres. These policies include direct operation of some marketing channels, manipulation of price structures through artificial exchange rates and price controls, and restrictive licensing practices. Wherever such policies have been applied in Kordofan, they have led to declining production of government controlled crops, they have restricted competition in marketing channels, and they have lowered living standards for producers and consumers. Sudan has not successfully identified areas where private channels in Kordofan cannot solve problems, and which therefore require public intervention. The government seems to have based its economic decisions upon ideological considerations and intervened in areas which it cannot perform as well as the private market.
|
212 |
Developing an integrated marketing communication strategy for the MGK GroupBronkhorst, N. J. 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2010. / ENGLISH ABSTRACT: The Marketing of Agricultural Products Act 47 (No 47 if 1996) led to the dilution of single-channel marketing in the agricultural sector. Hence, marketing boards such as the Maize Board were dismantled. New legislation forced agricultural businesses to adapt to the changing environment and turn co-operatives into companies. The new developments also implied that these companies had to reposition themselves to be more competitive in a deregulated market.
MGK Group Operating Company Pty (Ltd) is a prominent role player in the agricultural sector in the North West, Limpopo, Mpumalanga and Gauteng provinces in South Africa. Unexpected growth in the company as well as the deregulation of the industry necessitated a bona fide marketing communication department to manage and coordinate all advertising, promotional and communication efforts. After establishing this department all marketing communication efforts were still fragmented. Consequently, the cost-effectiveness of this department was questioned by the company’s board of directors.
The MGK Group’s the board of directors received a mandate to follow a holistic approach and formulate a strategy to enhance the impact of its marketing communication efforts while cutting costs. This study sets out to establish whether the implementation of an integrated marketing communication programme can ultimately satisfy the board of directors’ requirements for marketing communication that is more accountable, effective and efficient.
This study starts with a literature review of the practices and theories underpinning integrated marketing communication. This is followed by testing the applicability of the various approaches and methodologies in the MGK Group environment. The study is concluded with the formulation of a marketing communication strategy and recommendations based on the needs of the MGK Group. / AFRIKAANSE OPSOMMING: Die Wet op die Bemarking van Landbouprodukte (Nr 47 van 1996) het eenkanaal-bemarking in die sektor verwater. Dit het daartoe gelei dat bemarkingsrade soos die Mielieraad afgeskaf is. Nuwe wetgewing het landbou-ondernemings genoop om in 'n veranderende sake-omgewing aan te pas en koöperasies in maatskappye te omskep. Die aanpassing het ook beteken dat maatskappye hulself in 'n meer mededingende en gedereguleerde mark moes herposisioneer.
Die MGK Groep Bedryfsmaatskappy Edms Bpk is 'n vooraanstaande rolspeler in die landbousektor in die volgende provinsies in Suid-Afrika: Noordwes, Limpopo, Mpumalanga en Gauteng. Onverwagse groei asook die deregulering van die bedryf het meegebring dat dié maatskappy 'n bona fide bemarkingskommunikasie-afdeling nodig gehad het om alle reklame-, promosie- en kommunikasie-aktiwiteite te bestuur en te koördineer. Nadat die afdeling op die been gebring is, het bemarkingskommunikasie-aktiwiteite steeds los van mekaar gestaan. Dit het daartoe gelei dat die kostedoeltreffendheid van die funksie op divisievlak bevraagteken is.
Die direksie van die MGK Groep het 'n mandaat gehad om 'n holistiese benadering te volg en 'n strategie te formuleer om die impak sowel as die kostedoeltreffendheid van die maatskappy se bemarkingskommunikasie te verbeter. Hierdie studie poog om vas te stel of die implementering van 'n geïntegreerde bemarkingskommunikasieplan uiteindelik in die direksie van die MGK Groep se behoefte aan verantwoordbare, doeltreffende en doelmatige bemarkingskommunikasie kan voorsien.
Die studie begin met 'n literatuuroorsig van die praktyk en teorie van geïntegreerde bemarkingskommunikasie. Daarna word die toepaslikheid van die onderskeie benaderings en metodologieë ten opsigte van die MGK Groep getoets. Die studie word afgesluit met 'n bemarkingskommunikasiestrategie en aanbevelings wat op die behoeftes van die MGK Groep gegrond is.
|
213 |
Effect of preharvest UV-treatment on shelf life of fruits and vegetablesObande, Matthew A. January 2010 (has links)
The benefits of low UV dose treatment of horticultural produce – also known as hormetic treatment - have been attested to in numerous studies conducted over the last 15 years. However, commercial growers have not adopted the concept of hormesis. With increasingly stringent controls on the use of fungicides and other chemical agents the time has come to examine how hormetic treatment might be applied in the horticulture sector. The objectives of this work were firstly, to confirm UV-induced hormetic effects applied postharvest for a number of different types of produce, namely, tomatoes, broccoli, strawberries and mangoes. Secondly, to evaluate the use of rollers to ensure full surface treatment of produce, and thirdly to evaluate the possibility of treating produce preharvest. In order to investigate surface UV dose distributions, a polystyrene sphere (Diameter 70 mm) was used to simulate fruits such as tomatoes, apples, peaches etc., that have an approximately spherical form. Biodosimetry based on spores of Bacillus subtilis was employed to experimentally determine UV doses and to compare the results obtained with theoretical predictions. Good agreement was obtained and the modelling approach was extended to other types of produce. This showed the amenability of mechanical rollers to ensure full surface treatment of produce. Postharvest treatment of produce was carried using conventional low intensity UV sources principally emitting at 254 nm and also a commercially available high energy pulsed UV source. Treatment using the conventional UV source was carried out on mechanical rollers within a UV cabinet designed for this work at a fixed distance from the source and at an intensity of 1000 μW/cm2. A 5 minute conventional UV treatment of tomatoes was approximately comparable to fruit given a 3-pulsed treatment using the pulsed source (507 J/pulse of polychromatic light). The colour and texture of both groups of fruit were significantly maintained as compared with controls. The treated tomatoes also showed a significant increase in the ascorbic acid levels during storage. Similarly, a 15 minute conventional UV treatment of broccoli heads was comparable to heads given a 10-pulsed treatment using the pulsed source. Where both treatments gave rise to a statistically significant retention of green colour of treated broccoli. In addition, mangoes given a 10 minute conventional UV treatment were comparable to fruit given a 20-pulsed treatment using the pulsed source with both treatments leading to maintenance of texture as compared to control fruit. This confirmed the UV-hormetic effects. The effects of conventional and pulsed treatments are compared and discussed. Preharvest treatment of tomatoes and strawberries was carried out in commercial glasshouses. Doses of either 3 or 8 kJ/m2 were delivered to the fruits using a treatment device designed for the work, which delivered a combined intensity of 2000 μW/cm2 from two low pressure UV sources. The treated tomatoes showed a delay in development of colour as measured on the vine and after picking. Picked tomatoes were inoculated with P. digitatum and C. gloeosporioides and the results obtained showed a significant inhibition of the development of the fungi in the treated fruit during the storage period. These results suggest that the beneficial response shown by the preharvest treatment is not a localised one but a systematically induced resistance observable throughout the treated plant. This was shown by monitoring tomato fruits on treated plants which themselves where not directly exposed to the UV light. The two doses elicited different responses in the treated strawberries, with the 8 kJ/m2 dose causing the fruit to redden significantly faster than the 3 kJ/m2 treated fruits and controls. This could have significant nutritional benefit as the red colour of strawberries has been correlated with anthocyanin levels. On the other hand, treatment at the lower UV dose led to a lag in colour development. The amenability of the equipment utilised for commercial application is discussed.
|
214 |
Cause and Control of a Common Market Disease of LettucePalmore, William 01 March 1971 (has links)
Head lettuce, Lactuta sativa var. capitata, is susceptible to a number of economically important diseases, the most frequent being russet spot, rib discoloration, and vascular browning (28), which have been shown by Ceponis and Friedman (7) to be caused by Pseudomonas marginalis. Pseudomonads are common plant pathogens and cause such diseases as halo blight in beans (20), bacterial blight in soybeans (20), and bacterial wilt of the bird-of-paradise (27) and tobacco (24).
Plants that develop symptoms similar to russet of lettuce are oats, infected by Pseudomonas cichorii, and tobacco infected with Pseudomonas tobaci (34). In general, russet symptoms include few to numerous yellow, pink, brown, olive brown or dark brown irregular specks ranging in diameter from 1/16 to 1/8 inch (28). In tobacco these lesions are thought to result from a necrotizing toxin, diamino-dicarboxylic acid, beta-hydroxy-alpha, epsilon-aminopimelic acid, produced by the bacteria (34). In lettuce these lesions result from the bacterial enzymes, protopectinase and pectin depolymerase (7). The red discoloration of lettuce often encountered in grocery stores and home refrigerators has been given the name russet spot, rib discoloration, and tipburn, depending upon where the discoloration occurs (26). These terms are sometimes used interchangeably in the literature.
This investigation was initiated for two purposes: to determine factors which could be responsible for the symptoms which diseased market lettuce develops; and to investigate a preservation procedure that would best control the incidence of this disease.
|
215 |
Escherichia coli produtora de toxina de Shiga em vegetais orgânicos cultivados na região metropolitana de SP, São Paulo / Shiga toxin-producing Escherichia coli in organic vegetables produced in the area of São Paulo city, Brazil.Batalha, Erika Yamada 04 November 2015 (has links)
Escherichia coli produtora de toxina Shiga (STEC) está entre os patógenos envolvidos em surtos de doenças transmitidas por alimentos devido ao consumo de vegetais. No entanto, até agora, os relatos sobre a presença de STEC em vegetais no Brasil são escassos. Esse microrganismo é veiculado por alimentos, contaminados direta ou indiretamente por fezes animais, sendo responsável por um amplo espectro de doenças que compreende desde diarréia leve que pode evoluir para colite hemorrágica (CH), até síndrome hemolítico-urêmica (SHU) e púrpura trombocitopênica trombótica (PTT). O presente estudo teve como objetivo investigar a presença de STEC em vegetais orgânicos cultivados na região metropolitana da cidade de São Paulo, Brasil, caracterizando os fatores de virulência stx1, stx2, eae e ehx, bem como o sorotipo. Um total de 200 amostras de vegetais orgânicos (folhas verdes), obtido a partir de três produtores foi analisado quanto à presença de cepas de STEC. Caldo triptona de soja (TSB) suplementado com vancomicina (8 mg / L), cefixima (50 µg / L) e telurito de potássio (2,5 mg / L) foi utilizado na etapa de pré-enriquecimento, com incubação a 37ºC / 24 h, seguido por semeadura em MacConkey Sorbitol (SMAC) e CHROMagar STEC (CHROM). Após incubação a 37ºC / 24 h, as colônias suspeitas foram confirmadas por testes bioquímicos e submetidas a PCR objetivando a detecção dos genes de virulência stx1, stx2, eae, ehx, e os genes fliCH7 e rfbO157. Entre as 200 amostras de vegetais orgânicos analisadas, 30 (15%) foram positivas para E. coli, mas nenhum isolado apresentou os genes de virulência pesquisados. Nossos resultados indicam baixo risco de infecção devido ao consumo destes produtos frescos em São Paulo, Brasil. No entanto, são necessárias mais pesquisas, abrangendo um maior número de amostras e área pesquisada, uma vez que este patógeno já foi encontrado no meio ambiente em estudos anteriores e poucas pesquisas investigaram a presença de STEC em vegetais no Brasil. / Shiga toxin producing Escherichia coli (STEC) strains are among the pathogens involved in foodborne disease outbreaks due to consumption of vegetables. However, reports on the presence of STEC in vegetables in Brazil are lacking. STEC is an important pathogen transmitted by food, directly or indirectly contaminated with animal feces, responsible for a broad spectrum of diseases varying from mild diarrhea to hemorrhagic colitis (HC), syndrome hemolytic uremic (HUS) and thrombotic thrombocytopenic purpura (TTP). This study aimed at investigating the presence of STEC in organic vegetables in the metropolitan region of São Paulo city, Brazil, characterizing the virulence factors stx1, stx2, eae and ehx as well as identifying the serotype. A total of 200 samples of organic vegetables (green leafy), obtained from three organic producers was analyzed for the presence of STEC strains. Tryptic Soy Broth (TSB) supplemented with vancomycin (8mg/L), cefixim (50µg/L) and potassium telurite (2.5mg/L) was used in the pre enrichment step with incubation at 37°C/24 h, followed by plating onto Sorbitol-MacConkey (SMAC) agar and CHROMagar STEC (CHROM). After incubation at 37°C/24 h, presumptive colonies were confirmed by biochemical tests and submitted to PCR targeting the detection of stx1, stx2, eae and ehx virulence genes, as well as fliCH7 and rfbO157. Among the 200 organic vegetable samples analyzed for STEC strains, 30 (15%) were positive for E. coli, but none of them showed the virulence genes studied. These findings indicate low risk of infection due to the consumption of these fresh produce in Sao Paulo, Brazil. However, more research is required, covering a larger number of samples and area, since this pathogen has already been found in the environment in previous studies, and few research investigating the presence of STEC in vegetables has been reported in Brazil.
|
216 |
Consumer Willingness to Pay for Transitional Organic ProduceWilliams, Marissa 03 October 2013 (has links)
United States agriculture is continuing to shift toward organic production techniques to align with consumer demand, yet organic products make up an insignificant portion of the food market. This disparity has been examined via consumer willingness to pay for organic products and research on the costs and benefits of organic operations; however, little has been investigated about a potential transitional organic market. In shifting from conventional to organic agriculture there is a substantial transition phase of at least three years, during which producers cannot label their products as USDA organic. This research therefore examines consumer willingness to pay for transitional organic produce based on a Lane County representative adult population (n = 200). Results of the conjoint choice stated preference survey suggest that there exists a viable market for transitional organic products, revealing systematic heterogeneity in preferences for produce labeled as transitional USDA organic.
|
217 |
Na estrada dos enigmas, leituras e linguagens - imagem e palavra em cena. / On the enigma, reading and language road - images and words os stage.Braga, Patricia Colavitti 18 December 2006 (has links)
A tese Na Estrada dos Enigmas, Leituras e Linguagens - Imagem e Palavra em Cena propõe uma reflexão sobre a formação de professores de leitura e produção textual e relata uma prática de ensino que utiliza a arte como mediadora e, para isso, atenta que é preciso que o educador transite pelo universo da arte; assim, pretendemos mostrar como isso foi possível em nossa dimensão pedagógica, a partir de experiências intelectuais, artísticas, pedagógicas, emocionais que nos constituíram enquanto educadora. Retomando as palavras de Jean Lauand, ela serve \"no sentido daquela felicíssima confusão que a língua espanhola faz com a palavra enseñar: ensinar não só como ensinar, mas como mostrar\". Sendo assim, o primeiro capítulo se destinou a delinear, por meio das formas poéticas da vida, recriadas pela arte, uma reflexão acerca da formação do educador na sociedade contemporânea. Nosso intento foi descrever como mediamos um processo pedagógico com vistas à formação do educador contemporâneo, capaz de encontrar os arregalados olhos grandes que há dentro de cada alma formada e vertida pelo céu e pela ciência, e ver a realidade além da imagem e, a partir da sua contemplação, encontrar vias possíveis para a solução de seus próprios enigmas. E isso se justificou pelo fato de que na sociedade contemporânea, verificamos a emergência de nos constituirmos enquanto educadores que exerçam uma função social, que articulem seus saberes, planejem e concretizem o fazer pedagógico de forma realmente profissional, conscientes da responsabilidade perante o aprendiz que nos foi confiado, bem como perante aos outros integrantes do tecido social, e que alcancem com o objetivo de possibilitar a constituição de uma educação estética e, consequentemente, pela educação de seres humanos autônomos e melhores. No segundo capítulo, apresentamos um estudo que fundamenta a concepção de leitura do educador leitor e produtor de textos, apto a mediar a construção do conhecimento de seus alunos, no que concerne à leitura e à produção de textos. Partirmos da constatação de que não é possível extrair do vazio, a leitura e a produção textual. Por esse motivo, entendemos que é papel do educador despertar no aluno a consciência de que a leitura e a reflexão sobre o processo de composição textual desenvolvido por outros autores são elementos primordiais e fundamentais do processo de construção do seu (do aluno) texto, pois, leitura e conhecimento técnico são propulsores da compreensão e da interpretação, bem como contribuem para o fluir da criação. No terceiro capítulo, relatamos algumas práticas de leitura e produção de textos que desenvolvemos com nossos aprendizes, a fim de ilustrar que ensinar a produzir textos, longe da crença comum, não é simplesmente transmitir conhecimentos sobre definição de gêneros, modalidades e estrutura formal de produções discursivas; é sim um ato de extrema complexidade, pois exige que o leitor e, posteriormente, o produtor de textos, primeiramente, se emaranhe no tecido e na estrutura textual alheia para desvendá-los e, depois possa, finalmente, criar o próprio texto. E, além disso, possa também eleger destinos e dá-los a esses textos. E, finalmente concluímos, certos de que para a epifania da escrita ocorra, é preciso que a leitura salte para dentro da vida. / On the Enigma, Reading and Language Road - Images and Words on Stage is a study that proposes a reflection on the education of reading and text production teachers and reports on a teaching practice that uses art as medium, thus, calling attention to the need of educators to pass through the world of art. We intend to show how this is possible within our pedagogical dimension, and through the use of the intellectual, artistic, pedagogical, and emotional experiences we acquired as teachers. In Jean Lauand\'s words, it is used \"in the way that Spanish very delightfully confuses the word enseñar: enseñar means not only teach, but also show\". Therefore, the objective of the first chapter was to outline, through the poetic forms of life, recreated through art, a reflection on the education of the teacher in today\'s contemporary society. Our aim was to describe how we mediated the educational process in the development of today\'s teachers, capable of seeking deep inside their souls for the awareness of looking beyond the image, and through this contemplation, find possible solutions for their own enigmas. This was justified by the fact that in contemporary society we note the urgency of developing educators who actually perform a social function. These are educators who articulate knowledge, plan pedagogical activities and carry them out in a truly professional manner, conscious of their responsibilities to the learner who was entrusted to them, as well as to other participants in the social fabric and whose objectives are to provide an aesthetic education which will consequently result in the education of better and independent human beings. In the second chapter, we present a study based on the educator\'s concept of reading, on his/her capacity of acting as a medium in the building of knowledge in his/her students, in reference to reading and text production. We begin with the verification that it is not possible to extract reading or text production from empty space. For this reason, we understand that the role of the educator is to awaken the student\'s awareness to the fact that reading and reflecting on texts written by other authors are basic and fundamental principals for the student\'s own text production, because, reading and technical skills are the driving force to comprehension and interpretation, as well as contributors to the creative flow. In the third chapter we report some reading and text production practices that we developed along with our learners, to illustrate that teaching to produce texts, far from common belief, is not simply transmitting knowledge and defining genres, modes and formal discursive structures. Text production is an extremely complex activity, because it requires that the reader, who later will become a text producer him/herself, first be enmeshed in the texture and structure of someone else\'s text, to unveil it, so he/she may later create his/her own text, as well as determine the purpose and fate of these texts. We finally conclude that for a writer\'s epiphany to occur, reading must take a leap into life.
|
218 |
[en] KEY CAPABILITIES IN THE UK FRESH PRODUCE SUPPLY CHAIN PARTNERSHIP AS COMPLEMENTARY ELEMENTS FOR THE FRESH PRODUCE SUPPLY CHAIN PERFORMANCE MEASUREMENT MODEL / [pt] PROCESSOS OPERACIONAIS NAS PARCERIAS DA CADEIA DE FRUTAS E VEGETAIS DO REINO UNIDO ELEMENTOS COMPLEMENTARES PARA UM MODELO DE AVALIAÇÃO DE DESEMPENHO PARA A CADEIA DE SUPRIMENTOS DE ALIMENTOS FRESCOSHELIO ZANQUETTO FILHO 11 December 2003 (has links)
[pt] Nas últimas décadas, a literatura sobre Gerenciamento da
Cadeia de Suprimentos (GCS) tem ressaltado a necessidade de
colaboração entre os diversos atores (empresas
participantes) dentro da cadeia de suprimentos (CS). Assim,
as empresas necessitam de novos instrumentos para monitorar
não só o seu desempenho, mas também o desempenho da cadeia
como um todo. O desenvolvimento da tese está formulado
segundo duas óticas. A primeira, conceitual, refere-se ao
tema avaliação de desempenho na cadeia de suprimentos. A
segunda, gerencial, com a escolha da cadeia para o
desenvolvimento da pesquisa empírica. Nesse caso optou-se
pela cadeia de alimentos (frutas e vegetais) frescos e
minimamente processados do Reino Unido. Para direcionar a
pesquisa, dois objetivos principais foram formulados. O
primeiro consiste em comparar os elementos operacionais das
parcerias da cadeia de frutas e vegetais, identificados na
pesquisa empírica, com os benefícios e processos de
relacionamento observados na literatura. O segundo objetivo
visa formular um modelo teórico de avaliação de desempenho
para a cadeia de suprimentos de alimentos frescos - MADCS.
Para alcançar o primeiro objetivo, uma hipótes principal,
cinco hipóteses complementares e seis questões
exploratórias foram formuladas e estatisticamente testadas.
O segundo objetivo foi alcançado através da formulação do
MADCS utilizando-se a revisão bibliográfica em conjunto com
os resultados empíricos obtidos. A pesquisa amostral
(survey) foi escolhida como estratégia de pesquisa, e como
instrumento de pesquisa desenvolveu-se um questionário.
Foram enviados 303 questionários com retorno de 99 (32%).
Para o teste das hipóteses foram utilizados os seguintes
testes estatísticos: análise fatorial, teste qui-quadrado,
análise da variância, regressão logística e regressão linear
simples. Como conclusão dos testes estatísticos tem-se que
tanto os Benefícios, quanto os Processos de Relacionamento
(Individuais e Conjuntos) foram parcialmente confirmados.
Com relação às hipóteses complementares, três foram
estatisticamente confirmadas e em duas não havia evidências
estatísticas para confirmação. Na formulação do Modelo de
Avaliação de Desempenho para a Cadeia de Suprimentos
(MADCS) foi identificada a necessidade de incluir a
avaliação dos processos de relacionamento nos modelos até
então identificados na avaliação de desempenho das
parcerias. / [en] Supply chain management (SCM) has emerged as an important
strategic weapon for manufacturers seeking sustainable
competitive advantage. As a result, collaboration between
trading partners is replacing confrontation as the preferred
approach to buyer-supplier relationships. The focus of SCM
is the coordination and control of key business processes
throughout the supply chain, within and between firms. As a
result, researchers have sought to develop integrated
models of supply chain management in which firms are
treated as integral parts of four distinct flows -
information, value-added products, funds and knowledge .
This thesis has two main objectives: the first is to
identify and to compare the partnership capabilities
(benefits and processes) from the UK fresh produce industry
with the benchmark indicators from the literature. The
second one is to create a theoretical framework contributing
to the theory of supply chain performance measurement. One
main hypothesis, five complementary hypotheses and six
exploratory questions were formulated in relartion
to the primary research objective. In pursuit of the second
objective a performance measurement model for fresh
produce - MADCS was formulated. This model is supported by
the performance measurement theory and by empirical
results. A survey was choosen as the empirical research
strategy. To capture the data 303 questionnaries were sent
in February 2002 to UK fresh produce suppliers with
turnover of more than £ 1 million. To test the hypotheses,
chi-square, simple linear regression, factor analysis and
logistics regression techniques were used. Overall, the
results support the main hypothesis and three of the
remaining sub-hypotheses. However, there results do not
support the other two hypotheses.
|
219 |
A framework for flexible integration in robotics and its applications for calibration and error compensationTo, Minh Hoang January 2012 (has links)
Robotics has been considered as a viable automation solution for the aerospace industry to address manufacturing cost. Many of the existing robot systems augmented with guidance from a large volume metrology system have proved to meet the high dimensional accuracy requirements in aero-structure assembly. However, they have been mainly deployed as costly and dedicated systems, which might not be ideal for aerospace manufacturing having low production rate and long cycle time. The work described in this thesis is to provide technical solutions to improve the flexibility and cost-efficiency of such metrology-integrated robot systems. To address the flexibility, a software framework that supports reconfigurable system integration is developed. The framework provides a design methodology to compose distributed software components which can be integrated dynamically at runtime. This provides the potential for the automation devices (robots, metrology, actuators etc.) controlled by these software components to be assembled on demand for various assembly applications. To reduce the cost of deployment, this thesis proposes a two-stage error compensation scheme for industrial robots that requires only intermittent metrology input, thus allowing for one expensive metrology system to be used by a number of robots. Robot calibration is employed in the first stage to reduce the majority of robot inaccuracy then the metrology will correct the residual errors. In this work, a new calibration model for serial robots having a parallelogram linkage is developed that takes into account both geometric errors and joint deflections induced by link masses and weight of the end-effectors. Experiments are conducted to evaluate the two pieces of work presented above. The proposed framework is adopted to create a distributed control system that implements calibration and error compensation for a large industrial robot having a parallelogram linkage. The control system is formed by hot-plugging the control applications of the robot and metrology used together. Experimental results show that the developed error model was able to improve the 3s positional accuracy of the loaded robot from several millimetres to less than one millimetre and reduce half of the time previously required to correct the errors by using only the metrology. The experiments also demonstrate the capability of sharing one metrology system to more than one robot.
|
220 |
Marketing of agricultural produce with particular reference to vegetables:the case of small-scale farmers in the Northern ProvinceNdou, Khangale Seth January 2001 (has links)
Thesis (M.Sc. (Agricultural Economics)) --University of Limpopo, 2001.
|
Page generated in 0.078 seconds