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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.
11

Comparison and Fusion of space borne L-, C- and X- Band SAR Images for Damage Identification in the 2008 Sichuan Earthquake

LAU, SIN WAI January 2011 (has links)
Remote sensing has been widely used in disaster management. However, application of optical imageries in damage detection is not always feasible for immediate damage assessment. In the case of the Sichuan earthquake in 2008, the damaged areas were covered by cloud and fog for most of the time. The all weather SAR imageries could instead provide information of the damaged area. Therefore, more efforts are needed to explore the usability of SAR data. In regards to this purpose, this research focuses on studying the ability of using various SAR data in damage identification through image classification, and furthermore the effectiveness of fusion of various sensors in classification is evaluated.   Three different types of SAR imagery were acquired over the heavily damaged zone Qushan town in the Sichuan earthquake. The 3 types of SAR data are ALOS PALSAR L-band, RADARSAT-1 C-band and the TerraSAR-X X- band imageries.   Maximum likelihood classification method is applied on the imageries.  Four classes: Water, collapsed area, built-up area and landslide area are defined in the study area. The ability of each band in identifying these four classes is studied and the overall classification accuracy is analysed. Furthermore, fusion of these 3 types of imageries is performed and the effectiveness and accuracy of image fusion classification are evaluated.   The results show that classification accuracy from individual SAR imagery is not ideal. The overall accuracy which PALSAR gives is 30.383%, RADARSAT-1 is 31.268% while TerraSAR-X only achieves 37.168%. Accuracy statistics demonstrate that TerraSAR-X performs the best in classifying these four classes.   SAR image fusion shows a better classification result. Double image fusion of PALSAR and RADARSAT-1, PALSAR and TerraSAR-X, and RADARSAT-1 and TerraSAR-X give an overall classification accuracy of 41.88%, 42.478% and 37.758% respectively. The result from triple image fusion even reaches 52.507%. They are all higher than the result given by the individual images.   The study illustrates that the VHR TerraSAR X band SAR data has a higher ability in classification of damages, and fusion of different band can improve the classification accuracy.
12

System ecology of legumes mixes in ley production : impact on pollinating insects and further implications for production in northern Sweden

Simon, Philippe January 2023 (has links)
The population and diversity of pollinating insects in Europe are declining, partly due to lossof habitat. In agricultural landscapes, farming practices with more intensified land use haveincreased. In Swedish agricultural habitats, most ley production is dominated by grass and red clover (Trifolium pratense). The aim of this thesis is to assess whether a mixture of native legume species (more diverse than normally being used in ley production) can increase biodiversity of pollinating insects and provide better forage in northern Sweden. Several methods to assess increases in biodiversity of pollinating insects were conducted: (1) observational survey, (2) pollen analysis of bee pollen and honey, (3) legume flower pollencount, (4) nitrogen fixation of legume plants, (5) enrichment of microbes and molecular analysis of nectar and root nodules samples from legumes. Statistically significant differences could be found when testing legume flower pollen and observational data. The pollination ecology of legume mixes in ley production incorporates many different factors that could influence biodiversity of pollination insects. Though this thesis did not find statistically strong indications of increase in biodiversity of pollinating insects, further studies with more observational surveys and possible DNA metabarcoding could shed light regarding if increase of biodiversity of pollinating insects is possible or not regarding ley production habitats innorthern Sweden.
13

Autonomous navigation of an articulated vehicle in agriculture

Latif, Saira January 2022 (has links)
Disrupting agricultural vehicular automation is imperative for the solutions to global as well local challenges in agricultural production system. Historically, application of scientific and technological developments through increased mechanization and precision farming have provided several opportunities for agricultural production in general and within forage handling operations. Some promising engineering developments in the 20th century with regards to forage handling include forage harvesters, balers, and automated wrapping equipment of balers using stretch films of 25μm thick to lower risks of dust, molds, spores, mycotoxins respiratory allergenic disorders in livestock and humans. Baler machines has made it possible to trade silage (harvest and storage of moist grass using fermentation) in portable packages between farms which typically weigh 600-800 kg freshly cut per bale and are more popular on smaller farms with limited labor and financial resources to construct silos. Bales made up of hay or silage formed by balers are usually too heavy to be picked up by humans alone. Thus, they are picked up from fields using conventional utility vehicles such as tractors or loaders operated by a human. These kinds of operations are labor intensive and associated with health and accidents risks. There is also a potential to further improve the efficiency and environmental impact since most decisions are made by humans and thus limited to human labor capabilities in terms of load handling, sensing, multitasking, planning, consequence analysis etc. One significant contribution could be relieving the human operator from tedious driving task and incorporating optimize automated planning & driving functionality of field operations such as haybale collection. The focus of this thesis is to advance the existing autonomy level in agricultural vehicles for field operations. This is done by investigating current challenges and opportunities with agricultural vehicular automation and potential improvement for one of the field operations. Bales collection operation is one of the riskiest operations and taken as one case with potential for improvement with automation. Study of path planning approaches for bales collection operation in typical fields environment shows that optimized solution with concept autonomous articulated vehicle with neighborhood collection capabilities (ANV), can reduce working distance by 15-20% for this task. To further, a new approach of pure pursuit algorithm with increased reduction in tracking errors of an articulated vehicle is developed and evaluated.
14

”Äghornas kringgiärde är af steen” : Hägnadernas utformning före skiftesreformerna i Äskhults by och norra Halland / ”Äghornas kringgiärde är af steen” : The layout of fences in Äskhult and the northern parts of Halland before the land reforms

Hagbard, Oscar January 2019 (has links)
Äskhults by är idag ett kulturreservat och sedan 1990-talet har omfattande restaureringar gjorts, både i markerna och med byggnaderna. Ett mål för arbete i Äskhult är att återskapa landskapet så som det såg ut före skiftesreformerna. Därför har man använt skifteskartan från 1825 som utgångspunkt i restaureringsarbetet. Syftet med denna uppsats är att dra slutsatser kring hur hägnaderna såg ut under 1700-talet i denna trakten och därmed även bidra till arbetet med kulturreservatet. För att svara på frågor om hur hägnaderna såg ut före skiftesreformerna i norra Halland och varför vissa hägnadstyper förekom har Hallands landsbeskrifning från 1729 och geometriska avmätningar av Johan Söderlingh studerats. Källmaterialet indikerar att den dominerande hägnadstypen är av sten oavsett tillgången till material. Det förekommer dock trähägnader i området och då är det främst i form av ris. Det går att dra paralleller mellan trähägnadernas utbredning och förekomsten av skog i området. Skogsområdena ligger mot gränsen till Västergötland. En annan aspekt som kan ha påverkat förekomst och utformning av hägnader och som troligen inte syns i källmaterialet är tillfälliga hägnader. Tillfälliga hägnader kunde användas bland annat vid ljungbränning, efterbete eller tillfälliga kålgårdar. Därför borde det även funnits tillfälliga hägnader omkring Äskhult. Slutsatsen är dock att stenhägnader troligen var dominerande i området kring Äskhult.
15

Effect on Climate Change on Maize Production in Zambia

Ngoma, Justine January 2008 (has links)
<p>Maize is one of the crops that is grown by most farmers in Zambia being the staple food for the majority of Zambians. However, despite the crop being so important, its production is dependent on climatic conditions. This means that any change in climate can affect the production either negatively or positively. This research therefore, focused on determining how the change in temperature and rainfall affect maize production on the Copper belt, Eastern, Lusaka and Southern provinces of Zambia and investigate the main adaptation measures implemented by both the government and non-governmental sectors. Also, assess through the review of National Agricultural Policy and action plans, how the government has documented issues of climate change. In order to obtain the needed data, interviews were conducted with different officials from both the government and non-governmental sectors. However, from the estimate of the impact of temperature and rainfall on maize production, the results did not show with any significance that either temperature or rainfall has effect on maize production. In fact, it was found that quantifying the effects of climate change on maize production is not easy due to difficulties in quantifying other factors that may also have large impact on maize production. It was therefore, not possible to conclude whether or to what extent climate change has effects on maize production. However from the interviews conducted, it was found that both the government and non-governmental sectors have introduced different activities in their programmes to ensure that farmers are food secure, though the ministry of agriculture has no policy document on how to handle the problem of climate change to address different issues of the sector. In fact, most offices in the ministry do not have much documented information on climate change which could also be seen from the review of National Agricultural Policy and action plans where climate change issue has not been emphasized. Though both the Government and non-governmental sectors have implemented some adaptation measures, it cannot easily be concluded whether the implemented measures are adequate or not due to the fact that we are not sure of the expected effects in different parts of the country. Nevertheless, to enhance food security with or without adverse effects of climate change on maize production, it was recommended that members of staff at all levels under MACO should be trained in the area of climate change for them to have a wider understanding of the issue and work responsively and that much research should be done to open up the mind of the people and help policy makers make effective plans.</p>
16

Effect on Climate Change on Maize Production in Zambia

Ngoma, Justine January 2008 (has links)
Maize is one of the crops that is grown by most farmers in Zambia being the staple food for the majority of Zambians. However, despite the crop being so important, its production is dependent on climatic conditions. This means that any change in climate can affect the production either negatively or positively. This research therefore, focused on determining how the change in temperature and rainfall affect maize production on the Copper belt, Eastern, Lusaka and Southern provinces of Zambia and investigate the main adaptation measures implemented by both the government and non-governmental sectors. Also, assess through the review of National Agricultural Policy and action plans, how the government has documented issues of climate change. In order to obtain the needed data, interviews were conducted with different officials from both the government and non-governmental sectors. However, from the estimate of the impact of temperature and rainfall on maize production, the results did not show with any significance that either temperature or rainfall has effect on maize production. In fact, it was found that quantifying the effects of climate change on maize production is not easy due to difficulties in quantifying other factors that may also have large impact on maize production. It was therefore, not possible to conclude whether or to what extent climate change has effects on maize production. However from the interviews conducted, it was found that both the government and non-governmental sectors have introduced different activities in their programmes to ensure that farmers are food secure, though the ministry of agriculture has no policy document on how to handle the problem of climate change to address different issues of the sector. In fact, most offices in the ministry do not have much documented information on climate change which could also be seen from the review of National Agricultural Policy and action plans where climate change issue has not been emphasized. Though both the Government and non-governmental sectors have implemented some adaptation measures, it cannot easily be concluded whether the implemented measures are adequate or not due to the fact that we are not sure of the expected effects in different parts of the country. Nevertheless, to enhance food security with or without adverse effects of climate change on maize production, it was recommended that members of staff at all levels under MACO should be trained in the area of climate change for them to have a wider understanding of the issue and work responsively and that much research should be done to open up the mind of the people and help policy makers make effective plans.
17

Studies on the competitiveness of wood : - market segmentation and customer need assessments

Jonsson, Ragnar January 2005 (has links)
Over the last decades, wood has encountered increasing competition from other building materials. Hence, it is relevant to study the underlying factors of material substitution. The market for repair and remodelling (R&amp;R) is growing in importance. The end-consumer´s, or the household?s, assessments as to material selection are generally more crucial in R&amp;R than in construction of new houses, a circumstance highlighting the importance of the end-consumer. Consequently, this thesis deals with material substitution within an end-consumer context. Proper market segmentation and targeting presuppose an understanding of why households differ as to material preferences. Prioritising customer needs in quality improvement and/or product development requires information as to the importance of different customer requirements or needs as well as the performance of wood, relative substitutes, in providing for these needs. The thesis proposes a coherent approach for market segmentation and for prioritising customer needs: (i) how to provide a basis for market segmentation and targeting, i.e., to extract the distinguishing features of different material preferences; (ii) how to extract information enabling the prioritising of customer needs, i.e., importance and performance information. Identifying prominent discriminating factors of building application material preference, in order to subsequently explain why households differ within and between samples/cultures as to material preferences, and finally assessing customer requirements or needs as to the importance and the performance of wood relative substitutes in fulfilling them, presuppose an approach for data collection and analysis, which in turn requires a theoretical frame of reference. Hence, in the thesis a theoretical framework and different methods, for extracting decisive preferential predictors and assessing customer needs respectively, are suggested and evaluated. A pronounced design profile and distinct material alternatives make floorcovering a good illustrative example. The results indicate that material substitution with an end-consumer focus should be studied within a contextual framework. Hence, the usage context, the type of room refloored and whether the dwelling is owned or not, seems to define the types of materials actively considered. Further, households obviously differ in how they perceive the concept of floorcovering in a given usage context, depending on the general life situation and individual experience. Data collection, with the aim of identifying distinguishing factors of building application material preferences, must thus handle the collection of data related to usage context as well as the general life situation and individual experience. To obtain a deeper understanding of the underlying motives open-ended questions are called for. Performance benchmarking as to customer requirements or needs should be relative competitors in the same market segment, i.e., close substitutes. The assessment of customer needs should allow analysis on benefit levels, as alternatives in material substitution most readily can be compared in terms of the more abstract benefits/consequences they provide rather than concrete attributes. The apparent causal complexity, resulting from contextual influences, severely limits the usefulness and adequacy of traditional, additive, statistical analysis. Multivariate projection methods like partial least square discriminant analysis (PLS-DA); in coping with collinear variables, as well as the Boolean approach of qualitative comparative analysis (QCA); enabling data reduction in a theoretically guided manner, have potential for handling multiple conjunctural causation when analysing material preferences. Furthermore, both methods are able to handle binary variables resulting from open-ended questions, dependent as well as independent. PLS-DA can, however, more readily than Boolean algebra capture contextual influences. Analysis by means of PLS-DA thus seem to provide the information necessary for market segmentation and targeting, i.e., the causes of preferential differences both between and within cultures: evaluative criteria and variables related to the context. The output from the analysis of material preferences serve as input to the subsequent assessment of customer needs, as to the make-up of customer needs and as to which materials constitute close substitutes, i.e., share usage context. Customer satisfaction modelling (CSM) using partial least squares (PLS) seems well adapted for extracting the information necessary for prioritising customer needs: the impact on customer satisfaction of the fulfilment of different customer requirements or needs, and the performance of wood, relative substitutes, in providing for these needs. A valuable asset of CSM is the ability to allow analysis on customer benefit as well as attribute level. Usage context and data connected with the life situation provide instruments for market segmentation and targeting. For example: according to the present results, users of wooden flooring in the Netherlands are house owners to a greater extent and generally have a higher household income than users of laminated flooring. One of the apparently salient reasons for choosing wood, the natural material property, is part of the intrinsic nature, character, of the material. This quality of wood could provide an edge on the close substitute, laminated flooring. The results presented in the thesis further indicate that practical, functional, benefits exert the greatest impact on customer satisfaction, for wooden flooring as well as its closest substitutes laminate and carpet. This is noteworthy, as the salient evaluative criteria for choosing wooden flooring, unlike the other materials studied, were of a non-practical nature. This circumstance highlights the necessity of considering substitutes to identify latent needs. A low cost over the life cycle and hygiene are apparently the most important benefits to improve for wooden flooring manufacturers, as importance is high and performance relatively low.
18

Ett verktyg för sågoptimering av kubb / A tool for saw optimization of small diameter logs

Karlsson, Eric, Sturesson, Brian January 2013 (has links)
I detta examensarbete har ett användarvänligt verktyg skapats för att möjliggöra undersökningar av värdeutfallet vid kubbsågning på VIDA Alvesta AB. Verktyget har skapats i Microsoft Excel som för många är en känd miljö. Just nu är det svårt att få lönsamhet inom sågverksbranschen. Råvaran är dyr och det tvingar sågverken att effektivisera sin produktion. Det här verktyget har vankantsandel som viktigaste variabel eftersom det maximerar värdeutbytet genom att använda maximalt tillåtna vankanter. En undersökning för produkten 47x100 har gjorts med avseende att dölja vankanter med hjälp av rundade hörn med radie 3 och 5 mm. Undersökningen visade att det går att dölja en större vankant genom att öka hörnradien från 3 till 5 mm. En ytterligare åtgärd som kan utföras för att utnyttja råvaran på ett bättre sätt är att minska på råmåtten. Om råmåttet minskas med 3 % kan en ekonomisk vinning erhållas.
19

Opportunities and obstacles in the certification process : A case study on the development of the organic production and agriculture in Babati, Tanzania

Klang, Linda January 2010 (has links)
Organic products have become more and more talked- about in today’s industrial world. The demand for organic products is increasing and the market is continuing to grow bigger. It is important to maintain what these products stand for, being environmental friendly, and to do so strict certification policies are needed. EU has today an international certification body called Regulation (EC) 834/2007 that needs to be followed for export to and within EU. Parts of Tanzania today have certification of some organic products but not in Babati, that lies in the northern of Tanzania in Manyara region where this case study was done. In Babati most of the farmers are smallholder farmers and many of them, founds it difficult to afford an international certification. For the smallholder farmers to get a certification there are two alternatives. One is to go together with other smallholder farmers and apply for a certification like EUs Regulation (EC) 834/2007 as a group and then get to pay lower fees. The other alternative is to go together and start local certification bodies that have fees that are adjusted to local farmers’ income. This case study was conducted between February and March of 2010 in villages around Babati and Babati town. Interviews were held with both organic- and non organic farmers. My goal was to find out if it was possible for Babati to develop the organic agriculture and have an organic market in the future. My conclusion ends up by perceiving that Babati has a very good chance of fulfilling the Regulation (EC) 834/2007 standards. However the farmers’ economical status is an obstacle for the farmers to get an international certification, because of the high cost in inspections and reinspections.  But through a local certification body that is adjusted to the smallholder farmers and the environment the farmers can get their certificate and the organic market can be developed in Babati.
20

Abaca in the Philippines, an overview of a potential important resource for the country : Relating the tensile strength of the single fiber to the microfibrilar angle

Waller, Victor, Wilsby, Astrid January 2019 (has links)
Due to environmental concerns and to the limited amount of fossil fuel in the world theinterest in using renewable material has been and will continue to be on the rise. With theincreasing demand for renewable materials such as bio-based fibers, the research aroundnatural fibers is intensifying. Abaca (Musa Texitilis Nee) is a plant endemic to the Philippineswhich is claimed to contain the strongest natural fiber in the world 1. However, no thoroughresearch on performing tensile strength test on single abaca fibers/cells has been found. Byperforming tensile strength test on the single abaca fibers and relate this will provide freshdata about the single abaca fiber strength that can be compared with other natural fibers.This can later be a reference tool in order to find the optimal fiber for the product to be made. The purpose of this study is to develop a methodology for performing tensile strength testson single abaca fibers with the major objective to relate the tensile strength and E-modulusof the fibers with their microfibrillar angle (MFA). The research was done by using Abaca(grade S2) from Camarines Sur (Philippines) that was chemically disintegrated in order toobtain single fibers. The single fibers were mounted to a custom made paper frame for thetensile strength test performed by an Instron 5944. The MFA of each fiber was also retrievedusing an optical microscope with a polarized filter. The research showed an indication of aninversely proportional relation between MFA and tensile strength of the fibers. According tothe results, the E-modulus of the single abaca fiber was almost constant, independently onthe MFA of the fiber. / The purpose of this study is to do a broad map out of the abaca industry in the Philippines. Furthermore, the study aims to provide an overview of the abaca industry as a tool for finding ways to optimize the fiber production and to find suggestions on how to make a bigger share of the profit from the abaca products to stay by the farmers in the Philippines. The objectives are therefore also focused on describing the way the abaca plant is cultivated, harvested, processed, and further distributed from the farms. Also, the objectives are to describe the abaca supply and demand situation along with identifying challenges for abaca production. Today the outmoded abaca production in the Philippines is experiencing a productivity loss which makes the farmers' incomes unnecessarily low. Important factors that, by this study, have been identified affecting the low productivity and profit are lack of proper farming management, distribution and unoptimized usage of the fibers. A big share of the abaca fibers produced is also being exported. This means that the raw fibers are being made into high-value products abroad and hence the profit to be made is dislocated further from the farmers with low means of improving their standard of living. The study has been performed by doing a literature study complemented with interviews and visits to abaca farmers and other stakeholders within the abaca industry.

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