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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

Multivariate analysis and GIS in generating vulnerability map of acid sulfate soils.

Nguyen, Nga January 2015 (has links)
The study employed multi-variate methods to generate vulnerability maps for acid sulfate soils (AS) in the Norrbotten county of Sweden. In this study, the relationships between the reclassified datasets and each biogeochemical element was carefully evaluated with ANOVA Kruskal Wallis and PLS analysis. The sta-tistical results of ANOVA Kruskall-Wallis provided us a useful knowledge of the relationships of the preliminary vulnerability ranks in the classified datasets ver-sus the amount of each biogeochemical element. Then, the statistical knowledge and expert knowledge were used to generate the final vulnerability ranks of AS soils in the classified datasets which were the input independent variables in PLS analyses. The results of Kruskal-Wallis one way ANOVA and PLS analyses showed a strong correlation of the higher levels total Cu2+, Ni2+ and S to the higher vulnerability ranks in the classified datasets. Hence, total Cu2+, Ni2+ and S were chosen as the dependent variables for further PLS analyses. In particular, the Variable Importance in the Projection (VIP) value of each classified dataset was standardized to generate its weight. Vulnerability map of AS soil was a result of a lineal combination of the standardized values in the classified dataset and its weight. Seven weight sets were formed from either uni-variate or multi-variate PLS analyses. Accuracy tests were done by testing the classification of measured pH values of 74 soil profiles with different vulnerability maps and evaluating the areas that were not the AS soil within the groups of medium to high AS soil probability in the land-cover and soil-type datasets. In comparison to the other weight sets, the weight set of multi-variate PLS analysis of the matrix of total Ni2+& S or total Cu2+& S had the robust predictive performance. Sensitivity anal-ysis was done in the weight set of total Ni2+& S, and the results of sensitivity analyses showed that the availability of ditches, and the change in the terrain sur-faces, the altitude level, and the slope had a high influence to the vulnerability map of AS soils. The study showed that using multivariate analysis was a very good approach methodology for predicting the probability of acid sulfate soil.
12

Systém pro návrh optických sítí FTTH

Starý, Miroslav January 2017 (has links)
The thesis explains the principle of optical conduction and describes its possible structures. It also deals with the automation of designing, projecting, constructing FTTH optical networks, processing RUIAN data, creating plugins into the QGIS geographic information system and implementing them using the Python programming language.
13

Case study of a contract system : considering pulp prices from 1996-2006

Janstad, Tobias January 2007 (has links)
Södra Cell sells 1 900 000 ton pulp every year. Of this 490 000 tonne is sold with a contract system based on a pricing index called PIX NBSK. This index was started in 1996 and reflects the price of pulp from conferious forest. We study the NBSK PIX value of softwood from October 1996 to December 2006. People working in this branch known that there is strong periodicity in the prices. We use predictive analysis to see if clients can benefit from the periodicity and use the options in the contract system Södra offers today. We conclude that a drawback for the current contract system is that there are too many contracts in proportion to the duration time that is one year for all contracts. Using a time series model called ARMA we make successfull predictions the price difference between two contracts. Based on this prediction we change between these contracts, reducing the price with 0.81% in mean during 1997-2006. Due to the total turnover, if all clients would used such predictions during 1997-2006 Södra's income would have been reduced with 2.77 million USD a year in mean. The prices used before PIX are called list prices. The list prices seem to behave like the PIX index. Supposing that the same contract system we see in PIX today was used 1975-2006 with the list price as the base index I made a prediction of the list prices from 1986-2006. Thanks to my predictions, if I had been a client during this period and under mentioned considerations I would have been buying pulp to a price reduced with 0.57%. If clients had known the PIX between 1996-2006 in say 1995 Södra's contract system based on PIX would give them a price reduction that were 1.5% in mean during 1996-2006. Price reduction is not possible all years, but when it occurs it can be as big as 3% of the price. Suppose the clients always choose the contract with the lowest price and thereby get a reduced price over time. Then with 95% probability over a long period the price reduction is somewhere in between 0.4-2.7%. To strangle this price reduction possibility for the clients there are two ways to go: either reduce the number of contracts or extend the duration time of the contracts. To find a suitable duration time, we do spectral density estimation to get indications of which periods that are most important. From this we see that PIX index has a period of five years, wavelet approximated PIX index has 3.4 years and the list prices has a period of 5.6 years. This indicates that current duration time one year is too short. Therefore if it wouldn't effect Södra's clients, an extension of the duration time from one to five years would be good. If Södra don't extend the duration time of the contracts my recommendation is to have fewer contracts. The possibility to change between the contracts ''average last three months'' and ''average current month'' every other year is the weakest point of today's system. Therefore I recommend stop selling pulp to the contract ''average PIX last three months''. We can't prove any longterm difference between the contracts. If Södra chooses to have just one contract from this point of view it does not matter which one they choose. However, it seems like a good idea to follow the global market and therefore I recommend to choose ''average PIX current month'' rather than ''average PIX last three months'' which lags behind the market front. Since the price ''average current month'' is available at FOEX web page I think Södra should choose this contract if they decide to have only one contract. / Södra Cell säljer årligen 1 900 000 ton pappersmassa. Av denna mängd säljs 490 000 ton enligt ett kontraktsystem baserat på ett prisindex som heter PIX NBSK. Detta index introducerades 1996 och reflekterar priset på pappersmassa gjord av barrträd. Jag studerar priset på indexet från Oktober 1996 till December 2006. Dagens kontraktsystem är baserat på kontrakt med löptiden ett år. Jag undersöker om man kan prediktera prisskilllnaden mellan kontrakten, dra nytta att dagens löptid som bara är ett år och välja det kontrakt som ger det billigaste priset så ofta att priset över lång tid reduceras. När man predikterar gör man en uppskattningen av framtiden utifrån en modell av hur framtid beror på dåtid och nutid. Den modell jag har använt kallas ARMA. Denna tillsammans med priserna på pappersmassa från 1975 och framåt gav mig ett fruktbart sätt att förutsäga priserna. Resultatet blev ett pris reducerat med 0.81% i medel under perioden 1996-2006. Eftersom Södra ha så stor försäljningsvolym skulle de ha förlorat 2.27 miljoner dollar per ton i medel om alla kunder ha spekulerat utifrån den modellen jag använde. Om dagens kontraktsystem hade börjat användas 1975 med listpriserna som bas hade en kund som använt min prediktionsmetod fått ett pris reducerat med 0.57% under perioden 1986-2006. Om kunderna i förväg hade vetat priset under 1996-2001 gav det nuvarande systemet en reducerad medelintäkt med 1.5% av priset. Enskilda år reducerades intäkten med så mycket som 3%. Beräknar man konfidensintervall för prisreduktionerna så inser man att på lång sikt kommer dessa vara av storleksordningen 0.4-2.7% med sannolikheten 95%. Detta förutsatt att klienterna kan se in i framtiden. Siffran 2.7% alltså ett mått på hur stor risk man tar med dagens system. Jag tror inte att klienterna kommer reducera priset med 2.7% med nuvarande system, men det är en övre gräns. De gynsamma prediktionerna har sitt ursprung i att det finns periodicitet i priserna. Jag undersöker denna periodicitet med spektralanalys. Periodiciteten för PIX indexet är starkast kring 5 år. En wavelet-approximation av PIX-indexet hade störst periodicitet kring 3.4 år. Listpriserna hade starkast periodicitet kring 5.6 år. Detta indikerar att den nuvarande löptiden, ett år, är för kort. En lämpligare löptid för kontrakten är 5 år. Förmodligen är fem års löptid alltför lång tid att binda sig för många kunder. Därför föreslår jag att man reducerar antalet kontrakt istället. Den största svagheten i dagens system är den korta löptiden tillsammans med kontrakten ''average current month'' och ''average last three months''. Jag rekommenderar att man slutar erbjuda kontraktet ''average last three months''. Det allra säkraste är att endast erbjuda ett kontrakt. Vi har inte kunnat påvisa några skillnader över lång sikt mellan kontrakten såtillvida att något kontrakt skulle ge ett lägre medelpris än ett annat. Ur den aspekten är det godtyckligt vilket kontrakt man väljer, men det verkar vettigt att följa den globala marknaden. Därför är det eftersläpande kontraktet ''average PIX last three months'' inte att rekommendera, välj heller ''average PIX current month''. Ett annat argument för att välja ''average PIX current month'' är att dessa priser finns på FOEX hemsida och inga extra beräkningar behöver göras.
14

Case study of a contract system : considering pulp prices from 1996-2006

Janstad, Tobias January 2007 (has links)
<p>Södra Cell sells 1 900 000 ton pulp every year. Of this 490 000 tonne is sold with a contract system based on a pricing index called PIX NBSK. This index was started in 1996 and reflects the price of pulp from conferious forest. We study the NBSK PIX value of softwood from October 1996 to December 2006.</p><p>People working in this branch known that there is strong periodicity in the prices. We use predictive analysis to see if clients can benefit from the periodicity and use the options in the contract system Södra offers today. We conclude that a drawback for the current contract system is that there are too many contracts in proportion to the duration time that is one year for all contracts. Using a time series model called ARMA we make successfull predictions the price difference between two contracts. Based on this prediction we change between these contracts, reducing the price with 0.81% in mean during 1997-2006. Due to the total turnover, if all clients would used such predictions during 1997-2006 Södra's income would have been reduced with 2.77 million USD a year in mean.</p><p>The prices used before PIX are called list prices. The list prices seem to behave like the PIX index. Supposing that the same contract system we see in PIX today was used 1975-2006 with the list price as the base index I made a prediction of the list prices from 1986-2006. Thanks to my predictions, if I had been a client during this period and under mentioned considerations I would have been buying pulp to a price reduced with 0.57%.</p><p>If clients had known the PIX between 1996-2006 in say 1995 Södra's contract system based on PIX would give them a price reduction that were 1.5% in mean during 1996-2006. Price reduction is not possible all years, but when it occurs it can be as big as 3% of the price. Suppose the clients always choose the contract with the lowest price and thereby get a reduced price over time. Then with 95% probability over a long period the price reduction is somewhere in between 0.4-2.7%.</p><p>To strangle this price reduction possibility for the clients there are two ways to go: either reduce the number of contracts or extend the duration time of the contracts.</p><p>To find a suitable duration time, we do spectral density estimation to get indications of which periods that are most important. From this we see that PIX index has a period of five years, wavelet approximated PIX index has 3.4 years and the list prices has a period of 5.6 years. This indicates that current duration time one year is too short. Therefore if it wouldn't effect Södra's clients, an extension of the duration time from one to five years would be good.</p><p>If Södra don't extend the duration time of the contracts my recommendation is to have fewer contracts. The possibility to change between the contracts ''average last three months'' and ''average current month'' every other year is the weakest point of today's system. Therefore I recommend stop selling pulp to the contract ''average PIX last three months''.</p><p>We can't prove any longterm difference between the contracts. If Södra chooses to have just one contract from this point of view it does not matter which one they choose. However, it seems like a good idea to follow the global market and therefore I recommend to choose ''average PIX current month'' rather than ''average PIX last three months'' which lags behind the market front. Since the price ''average current month'' is available at FOEX web page I think Södra should choose this contract if they decide to have only one contract.</p> / <p>Södra Cell säljer årligen 1 900 000 ton pappersmassa. Av denna mängd säljs 490 000 ton enligt ett kontraktsystem baserat på ett prisindex som heter PIX NBSK. Detta index introducerades 1996 och reflekterar priset på pappersmassa gjord av barrträd. Jag studerar priset på indexet från Oktober 1996 till December 2006.</p><p>Dagens kontraktsystem är baserat på kontrakt med löptiden ett år. Jag undersöker om man kan prediktera prisskilllnaden mellan kontrakten, dra nytta att dagens löptid som bara är ett år och välja det kontrakt som ger det billigaste priset så ofta att priset över lång tid reduceras. När man predikterar gör man en uppskattningen av framtiden utifrån en modell av hur framtid beror på dåtid och nutid. Den modell jag har använt kallas ARMA. Denna tillsammans med priserna på pappersmassa från 1975 och framåt gav mig ett fruktbart sätt att förutsäga priserna. Resultatet blev ett pris reducerat med 0.81% i medel under perioden 1996-2006. Eftersom Södra ha så stor försäljningsvolym skulle de ha förlorat 2.27 miljoner dollar per ton i medel om alla kunder ha spekulerat utifrån den modellen jag använde.</p><p>Om dagens kontraktsystem hade börjat användas 1975 med listpriserna som bas hade en kund som använt min prediktionsmetod fått ett pris reducerat med 0.57% under perioden 1986-2006.</p><p>Om kunderna i förväg hade vetat priset under 1996-2001 gav det nuvarande systemet en reducerad medelintäkt med 1.5% av priset. Enskilda år reducerades intäkten med så mycket som 3%. Beräknar man konfidensintervall för prisreduktionerna så inser man att på lång sikt kommer dessa vara av storleksordningen 0.4-2.7% med sannolikheten 95%. Detta förutsatt att klienterna kan se in i framtiden. Siffran 2.7% alltså ett mått på hur stor risk man tar med dagens system. Jag tror inte att klienterna kommer reducera priset med 2.7% med nuvarande system, men det är en övre gräns.</p><p>De gynsamma prediktionerna har sitt ursprung i att det finns periodicitet i priserna. Jag undersöker denna periodicitet med spektralanalys. Periodiciteten för PIX indexet är starkast kring 5 år. En wavelet-approximation av PIX-indexet hade störst periodicitet kring 3.4 år. Listpriserna hade starkast periodicitet kring 5.6 år. Detta indikerar att den nuvarande löptiden, ett år, är för kort. En lämpligare löptid för kontrakten är 5 år.</p><p>Förmodligen är fem års löptid alltför lång tid att binda sig för många kunder. Därför föreslår jag att man reducerar antalet kontrakt istället. Den största svagheten i dagens system är den korta löptiden tillsammans med kontrakten ''average current month'' och ''average last three months''. Jag rekommenderar att man slutar erbjuda kontraktet ''average last three months''. Det allra säkraste är att endast erbjuda ett kontrakt. Vi har inte kunnat påvisa några skillnader över lång sikt mellan kontrakten såtillvida att något kontrakt skulle ge ett lägre medelpris än ett annat. Ur den aspekten är det godtyckligt vilket kontrakt man väljer, men det verkar vettigt att följa den globala marknaden. Därför är det eftersläpande kontraktet ''average PIX last three months'' inte att rekommendera, välj heller ''average PIX current month''. Ett annat argument för att välja ''average PIX current month'' är att dessa priser finns på FOEX hemsida och inga extra beräkningar behöver göras.</p>
15

Loajalita a spokojenost účastníků Street Dance Kemp s nabídkou služeb akce / Participant loyalty and satisfaction with services offered on Street Dance Kemp

Štrbíková, Barbara January 2014 (has links)
Participant loyalty and satisfaction with services offered on Street Dance Kemp Goal: Main goal of this thesis is to find a relationship between participant loyalty and satisfaction with services offered on Street Dance Kemp. Methods: In this thesis is used questionnaire and structured interview for obtaining data about participant satisfaction with services offered and about their loyalty to the event. Will be also examined the available competition in dance camps in Europe. To find a relationship between participant loyalty and satisfaction is used statistical method Kruskal-Wallis non-parametrical ANOVA. Results: Main result of this thesis is evaluation of the relationship between participant loyalty and satisfaction and future possible improvement of the services in order to get more loyal participants. Key words: sport event, street dance, hip-hop, questionnaire and interview, competition analysis, Kruskal-Wallis ANOVA
16

An Agent-Based Model of Ant Colony Energy and Population Dynamics: Effects of Temperature and Food Fluctuation

Xiaohui, Guo 01 August 2014 (has links)
The ant colony, known as a self-organized system, can adapt to the environment by a series of negative and positive feedbacks. There is still a lack of mechanistic understanding of how the factors, such as temperature and food, coordinate the labor of ants. According to the Metabolic Theory of Ecology (MTE), the metabolic rate could control ecological process at all levels. To analyze self-organized process of ant colony, we constructed an agent-based model to simulate the energy and population dynamics of ant colony. After parameterizing the model, we ran 20 parallel simulations for each experiment and parameter sweeps to find patterns and dependencies in the food and energy flow of the colony. Ultimately this model predicted that ant colonies can respond to changes of temperature and food availability and perform differently. We hope this study can improve our understanding on the self-organized process of ant colony.
17

Influência do ciclo hidrológico em pescarias comerciais na Amazônia Central, Brasil

Gonçalves, Vinícius Verona Carvalho, 92-99213-4998 23 April 2018 (has links)
Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-20T18:39:36Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_finalizada.pdf: 1987710 bytes, checksum: 46c6e0b1f07f99706e86684cdd0bd406 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-20T18:39:46Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_finalizada.pdf: 1987710 bytes, checksum: 46c6e0b1f07f99706e86684cdd0bd406 (MD5) / Made available in DSpace on 2018-06-20T18:39:47Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_finalizada.pdf: 1987710 bytes, checksum: 46c6e0b1f07f99706e86684cdd0bd406 (MD5) Previous issue date: 2018-04-23 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the Central Amazon, the fisheries are artisanal in character, being practiced by fishermen in rivers and flooded areas. Thus, the main issue addressed in the study is to verify how the hydrological cycle influences the catches of species, considering that the landing is made up of species with different feeding strategies. Firstly, we carried out a previous characterization of the fisheries, in order to determine the main environments and species exploited, as well as, more productive and attractive periods for the fishing activity. We also list the fishing gear used by fishermen with the target species. The characterization indicated that the lake environments are more exploited by the fishermen, however, most of the catches come from the river channels. In relation to the composition of the landing, a total of 34 species were landed, being the jaraqui coarse scale (Semaprochilodus taenirus) and the jaraqui fine scale (Semaprochilodus insignis) the most exploited species. The period of flood presented a significant difference in the catch values per unit of effort (CPUE) when compared to the other hydrological periods. The fishing gear varied according to the environment where the fishing occurred and the species to be exploited. Later, we used generalized linear models (Covariance Analysis - ANCOVA) to determine the influence of the river level on the fisheries in the Lower Solimões River. The analysis of covariance for the flood period showed that all species were influenced by river level, and by fishing effort, there was still a positive interaction between fishing effort and detritus species. During the flood period, the fishing effort positively influenced all species, there was also a positive interaction between fishing effort, detritivorous and herbivorous species and a positive effort in river environments. In the ebb period, only the fishing effort was significant, with a negative interaction between the fishing environment and the effort. In the dry season, only the omnivorous species were influenced by the fishing effort and the level of the river, with negative interaction between fishing effort and omnivorous species. The results found may contribute to the generation of knowledge about fishing activities, providing information for the construction of public policies related to fisheries management in the state of Amazonas. / Na Amazônia Central as pescarias possuem caráter artesanal, sendo praticadas por pescadores em rios e áreas alagadas, sendo altamente influenciadas pela variação do nível do rio. Desse modo, a principal questão abordada no estudo é verificar como o ciclo hidrológico influencia nas capturas de espécies, considerando que o desembarque é constituído de espécies com diferentes estratégias alimentares. Primeiramente, realizamos uma caracterização prévia das pescarias, no intuito de determinar os principais ambientes e espécies explotados, bem como, períodos mais produtivos e atrativos para a atividade pesqueira. Também relacionamos os apetrechos de pesca utilizados pelos pescadores com as espécies alvo. A caracterização indicou que os ambientes de lago são mais explotados pelos pescadores, no entanto, a maior parte das capturas é oriunda dos canais de rios. Em relação à composição do desembarque, foram desembarcadas um total de 34 espécies, sendo o jaraqui escama grossa (Semaprochilodus taenirus) e o jaraqui escama fina (Semaprochilodus insignis) as espécies mais explotadas. O período de cheia apresentou valores positivos na captura por unidade de esforço (CPUE) quando comparado aos demais períodos hidrológicos. As artes de pesca variaram de acordo com o ambiente onde ocorreu a pesca e as espécies a serem explotadas. Posteriormente, utilizamos modelos lineares generalizados (Análise de covariância – ANCOVA) para determinar a influencia do nível do rio sobre as pescarias no Baixo Rio Solimões. A análise de covariância para o período de enchente mostrou que todas as espécies foram influenciadas pelo nível do rio, e pelo esforço de pesca, houve ainda uma interação positiva entre o esforço de pesca e espécies detritívoras. No período de cheia, o esforço de pesca influenciou positivamente todas as espécies, houve ainda uma interação positiva entre o esforço de pesca, espécies detritívoras e herbívoras e um esforço positivo nos ambientes de rio. No período de vazante, apenas o esforço de pesca foi significativo, com uma interação negativa entre o ambiente de pesca e o esforço. No período de seca, apenas as espécies onívoras foram influenciadas pelo esforço de pesca e o nível do rio, com interação negativa entre o esforço de pesca e espécies onívoras. Os resultados encontrados contribuem para a geração de conhecimento sobre atividades de pesca, fornecendo informações para a construção de políticas públicas relacionadas à gestão da pesca no estado do Amazonas.
18

COMPARISON OF THE GROWTH OF SHIGA TOXIN-PRODUCING ESCHERICHIA COLI (STEC) ON DIFFERENT MEDIA

Wang, Gaochan 26 June 2012 (has links)
No description available.
19

Farmers' Markets in Kentucky: A Geospatial, Statistical, and Cultural Analysis

Schmitz, Elizabeth Ann 01 December 2010 (has links)
To assess what factors are driving the exponential growth of farmers’ markets in Kentucky, geospatial and statistical analysis of a database of 121 farmers’ markets was conducted. A statewide survey of market leaders and a case study of a single farmers’ market both identified reasons for growing support of farmers’ markets in Kentucky. Market distribution, vendor levels, and gross sales were mapped against a backdrop of county urban classification, median household income, and education levels. Kruskal-Wallace analysis was used to identify if Kentucky’s rural, micropolitan, and metropolitan markets differ significantly in terms of their age, number of vendors, and market sales. Geospatial analysis indicates that farmers’ markets are more concentrated in metropolitan areas of the Commonwealth. However, statistical analysis reveals that farmers’ markets have been established longer in micropolitan areas of the state. Markets across urban classes have significantly different ages and gross sales, but all markets tend to sustain a similar number of vendors. Population levels appear to have the strongest correlation with the variables studied, although education and household median income also may play a role in farmers' market strength. Market stakeholders believe that markets are gaining popularity as consumers become more aware of food safety and environmental problems in the mass market system. Farmers’ markets are considered an important tool for strengthening the local economy, connecting farmers with consumers, and increasing local availability of fresh and nutritious foods.
20

Ecological Informatics: An Agent Based Model on Coexistence Dynamics

Thapa, Shiva 01 August 2017 (has links) (PDF)
The coexistence of species is probably one of the most interesting and complex phenomenon in nature. We constructed an agent based model to study the coexistence dynamics of prey - predator populations by varying productivity levels of producers in fragmented and connected habitats along with different levels of quality of predators. Our results indicated that productivity levels of producers in fragmented and connected habitats along with levels of predator quality are significantly responsible for overall predator - prey population size and survivorship. In the absence of predation, competition between identical prey populations is more probable in connected habitats than in unfragmented or fragmented habitats. Implementing low quality predators in the habitats positively influences the overall coexistence dynamics whereas implementing high quality predators tend to decrease the prey populations. Fragmented habitats provide for greater prey population survival time in highly productive environments but low prey population survival time in less productive environments.

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