Master of Science

It widely is assumed that property markets can be predicted and to be able to make forecasts, concerning future housing prices, a number of different indicators are used. But if it possible to know the future today, why do we still experience bubbles in housing markets? To answer this question the reliability of four of the most commonly used indicators were tested for the time period between 2000 and 2010. To evaluate the indicators predicting power the development in, Germany, Sweden, Spain and the UK was studied. Germany and Sweden did not experience a correction during the most recent financial crises, while Spain and the UK did. If the evaluated indicators would be good predictors of future developments, it should have been possible to see differences in the attained values prior to the crises and it should have been easy to forecast that prices would fall in the UK and Spain and that they would be fairly stable in Germany and continue to increase in Sweden. The results from this study do not support the statement, that property prices can be forecasted, but, on the contrary, indicates that the investigated indicators have very limited predictive power in forecasting future price developments in housing markets. The result also show that variable rate mortgages can be expected to play a smoothing effect on property prices during economic cycles.

It widely is assumed that property markets can be predicted and to be able to make forecasts, concerning future housing prices, a number of different indicators are used. But if it possible to know the future today, why do we still experience bubbles in housing markets? To answer this question the reliability of four of the most commonly used indicators were tested for the time period between 2000 and 2010. To evaluate the indicators predicting power the development in, Germany, Sweden, Spain and the UK was studied. Germany and Sweden did not experience a correction during the most recent financial crises, while Spain and the UK did. If the evaluated indicators would be good predictors of future developments, it should have been possible to see differences in the attained values prior to the crises and it should have been easy to forecast that prices would fall in the UK and Spain and that they would be fairly stable in Germany and continue to increase in Sweden. The results from this study do not support the statement, that property prices can be forecasted, but, on the contrary, indicates that the investigated indicators have very limited predictive power in forecasting future price developments in housing markets. The result also show that variable rate mortgages can be expected to play a smoothing effect on property prices during economic cycles.

Bakgrund . Moderna spel blir mer krävande på hårdvaran och för att motverka detta utvecklas nya tekniker för att lätta på dessa krav. En sådan optimeringsteknik är Variable Rate Shading (VRS), som ingår i DirectX 12 API. Det tillåter utvecklare att variera kvaliteten på delar av ramen för att förbättra prestanda. Hur effektiv VRS är, verkar variera eftersom olika benchmark-testare får olika resultat. Detta beror med största sannolikhet på de olika scenmiljöer som används i testerna. Mål . För att ytterligare utöka de miljöer som används VRS bench-tester kommer denna studie att fokusera på att mäta och utvärdera hos VRS i en lätt miljö som skiljer sig från andra. Metoder . Metoden består av att utveckla en lättviktig Direct3D 12-applikation, implementera VRS-tekniken och mäta prestanda. För en tydlig utvärdering genomförs flera tester som mäter bildrutetid, bildhastighet och ritar samtalshastighet vid de olika inställningarna med hjälp av VRS-tekniken vid olika upplösningar över 1000 iterationer. Resultat . Genom att mäta bildrutetid, bildfrekvens och dragsamtalshastighet med VRS var det möjligt att samla in prestationsdata som visa i denna studie. Studien visar den genomsnittliga prestandan med 1x1, 2x2 och 4x4 skugghastigheter vid 480p, 1080p och 2160p upplösning. Medeldata jämfördes mellan skuggningshastigheter och upplösningar för att undersöka korrelationen och avvikelsen. Som förväntat visas generella prestandaförbättringar vid användning av VRS. Vissa inställningar visade dock inkonsekvens i avvikelser mellan skuggningshastigheter, och andra visade försämrad prestanda. Slutsatser . Slutsatsen från denna studie tider på att VRS förbättrar prestanda även i lätta applikationer, inom rimliga gränser. Prestandavinsten var dock av lägre grad vid jämförelse med andra benchmarktester. Detta tyder på att VRS är mer användbar i mer krävande miljöer.

Weeds typically grow in patches across agricultural landscapes. Because of this characteristic growth pattern, it seems logical to apply herbicides site-specifically to control them. To do this effectively, methods must be identified to accurately map weed presence and make cost effective herbicide application decisions to control them. The primary objective of this research was to develop a site-specific herbicide decision support system. Additional objectives include evaluating the effects of sampling patterns and interpolation techniques for weed mapping accuracy and evaluating texture analysis for weed patch detection in row-crops. A geographic information system (GIS) extension was developed to work in conjunction with a commercial software component for calculating site-specific herbicide applications based on user input weed maps. Results of the extension were compared to that of the commercial software. The GIS extension was able to accurately develop herbicide options based on the given weed densities and potential net return for treatment of the weeds in any specific area of the field. Sampling techniques and interpolation methods were compared to assess the accuracy of each pattern/method combination. The patterns used in this study were the W- and Z-shaped pattern, and the interpolation methods used were kriging and inverse distance weighted. Neither the pattern nor method impacted the results of the predicted average values for a given weed species. The last objective addressed was texture analysis? ability to distinguish weed patches in row-crops. Texture analysis was also tested to determine its ability to distinguish between areas requiring a herbicide application and areas not requiring a herbicide application. The analysis was performed on 3 vegetative indices and the NIR band of multispectral imagery at three different spatial resolutions (0.14 m, 0.5 m, and 1 m), and for two dates in the growing season. Texture analysis performed better on late season for both scenarios, with the highest classification accuracies (45 to 75%) coming from distinguishing areas that were below a given weed threshold from those that were above.

No description available.

Engine-triggered tasks are real-time tasks that are released when the crankshaft arrives at certain positions in its path of rotation. This makes the rate of release of these jobs a function of the crankshaft's angular speed and acceleration. In addition, several properties of the engine triggered tasks like the execution time and deadlines are dependent on the speed profile of the crankshaft. Such tasks are referred to as adaptive-variable rate (AVR) tasks. Existing methods to calculate the worst-case demand of AVR tasks are either inaccurate or computationally intractable. We propose a method to efficiently calculate the worst-case demand of AVR tasks by transforming the problem into a variant of the knapsack problem. We then propose a framework to systematically narrow down the search space associated with finding the worst-case demand of AVR tasks. Experimental results show that our approach is at least 10 times faster, with an average runtime improvement of 146 times for randomly generated task sets when compared to the state-of-the-art technique. / Master of Science / Real-time systems require temporal correctness along with accuracy. This notion of temporal correctness is achieved by specifying deadlines to each of the tasks. In order to ensure that all the deadlines are met, it is important to know the processor requirement, also known as demand, of a task over a given interval. For some tasks, the demand is not constant, instead it depends on several external factors. For such tasks, it becomes necessary to calculate the worst-case demand. Engine-triggered tasks are activated when the crankshaft in an engine is at certain points in its path of rotation. This makes their activation rate dependent on the angular speed and acceleration of the crankshaft. In addition, several properties of the engine triggered tasks like the execution time and deadlines are dependent on the speed profile of the crankshaft. Such tasks are referred to as adaptive-variable rate (AVR) tasks. Existing methods to calculate the worst-case demand of AVR tasks are either inaccurate or computationally intractable. We propose a method to efficiently calculate the worst-case demand of AVR tasks by transforming the problem into a variant of the knapsack problem. We then propose a framework to systematically narrow down the search space associated with finding the worst-case demand of AVR tasks. Experimental results show that our approach is at least 10 times faster, with an average runtime improvement of 146 times for randomly generated task sets when compared to the state-of-the-art technique.

Master of Agribusiness / Department of Agricultural Economics / Gregory Ibendahl / One of the latest buzzes amongst agriculture is the storage and analysis of “Big Data.” There are a number of questions surrounding the quality, quantity, and capacity of big data to form real-world decisions based upon past information. Much like the teachings of history, the storybook that big data can reveal about a grower’s operation may hold the answers to the question of: “what is necessary to increase food production which will be required to feed an ever-growing world?” With the increase in interest in precision agriculture, sustainability practices, and the processing of the immense spatial dataset generated on the farm, the next challenge at hand will be in determining how to make technology not only streamlined, but also profitable. Over the past few years, precision agriculture technology has become widely adopted as an agronomic decision making tool. Much like a scientific experiment, the greater the number of similar observations, the greater the degree of confidence can be placed upon a decision. As a means of increasing the number of observations that a farmer can use to base a decision upon, there is becoming increasing demand in being able to combine the data of similar farming operations in order to increase the size and scope of the dataset to generate better decisions benefitting many farms instead of just one. The growing interest in forming community data pools for farm data demonstrates the need for a study for determining how farming practices can be properly benchmarked. The goal was be to evaluate how to use farm data to make economic decisions in a similar manner as one would make agronomic decisions using similar observations. The objective was to design the proper protocol for benchmarking the farm’s potential, and evaluating potential increases in technical efficiency by adopting precision agriculture technology. To accomplish this, a data envelopment analysis was conducted using scale efficiency as a means of determining the frontier of efficient farms. The resounding goal for this study in the future will be to use the model as a means of implementing the secondary process of pooling precision agriculture data to analyze efficiencies gained by the adoption of technology. By demonstrating the value of generating peer groups to increase observations and refine farming practices, farmers can find increased profitability and efficiency by using resources that may already be held within the operation.

Com as novas tecnologias de produção visando maiores lucratividades e sustentabilidade, as técnicas e ferramentas da agricultura de precisão (AP) vêm sendo avaliadas pelos produtores na gestão de pomares comerciais de citros. A AP leva em consideração a desuniformidade das lavouras, tentando buscar soluções e ferramentas para melhor explorar tais variabilidades. As técnicas propostas se baseiam na variabilidade espacial existente no campo e em ações de manejo implementadas de forma localizada, em taxa variável, ou seja, de acordo com a demanda local pelos insumos. Já existem metodologias para confecção de mapas de produtividade em citros, um dos passos essenciais para o início da implantação da AP nas propriedades, e assim, o possível processamento dos dados e aplicação de fertilizantes e corretivos em taxas variadas. O objetivo deste trabalho foi avaliar os efeitos de aplicações em taxa fixa e variável sobre a produtividade e os parâmetros de fertilidade do solo bem como sobre o consumo de fertilizantes e calcário em talhões de citros em larga escala (ao longo de sete safras). O estudo foi conduzido durante sete anos, de 2011 a 2017 e englobou áreas experimentais em pomares que se localizam na fazenda Rio Pardo, município de Iaras - SP (22º57\'03,5\"S; 48º39\'37,4\"W) e consistiam em dez talhões de aproximadamente 25 hectares implantados em 2008 e 2009. Cinco talhões foram conduzidos utilizando o tratamento \"Dose fixa\" (DF) e cinco \"Dose variável\" (DV). O processamento dos dados consistia na realização da análise exploratória inicial, filtragens e limpezas, análises geoestatísticas, interpolações e recomendações dos insumos. No tratamento DF, os insumos foram aplicados seguindo a metodologia convencional de adubação, uma amostra de solo e folha era retirada de cada talhão e com base na expectativa de produção, a necessidade de insumos era calculada. No tratamento DV, as amostragens eram georreferenciadas e realizadas a cada um hectare. As recomendações de fósforo, potássio, calcário e nitrogênio foram calculadas com base nos mapas de produtividade do ano anterior e com os resultados laboratoriais das amostragens. As aplicações de P, K e N do tratamento DV não foram reduzidas quando comparadas às aplicações do tratamento DF, porém as aplicações em doses variadas apresentaram maiores eficiências na aplicação. Os valores médios de P e K nos solos se diferiram estatisticamente somente nos anos de 2013/14 e 2014/15, sendo maiores no tratamento DV. A produtividade no tratamento DV foi maior quando comparada ao tratamento DF e nas comparações entre os anos, em quatro safras o tratamento DV apresentou maiores produtividades, chegando a aumentos de 26% de produção de frutas e cerca de 2,74 t ha-1 na média nos seis anos avaliados. / With all the new and advance in production technologies, that aims for a greater profitability and sustainability, techniques and tools used in precision agriculture (PA) are starting to be evaluated by the producers in the management of citrus commercial fields. PA considers the unequal nature of the crops, willing to find solutions and procedures to exploit such variabilities with better results. The proposed techniques are based on spatial variability in the field and on management actions implemented locally, at varied rates, in other words, according to local demand for inputs. It is known that already exists some methodologies for making and developing maps of citrus productivity, one of the essential procedures of the implantation of PA in properties, and thus, the possible processing of data and application of fertilizers and correctives in varied rates. The objective of this paper was to evaluate the effects of fixed and variable rate applications on productivity and soil fertility parameters as well as on fertilizer and limestone consumption in large-scale citrus stands (over seven harvests). The study was developed for seven years, from 2011 to 2017 in experimental areas within orchards located in the Rio Pardo farm, in the municipality of Iaras - SP (22º57\'03.5 \"S; 48º39\'37.4\" W) and consisted of ten plots of approximately 25 hectares established in 2008 and 2009. Five plots were conducted using the \"Fixed-rates\" (DF) and five \"variable rates\" (DV) treatments. The data processing procedure consisted of performing the initial exploratory analysis, filtering and cleaning data, geostatistical analysis, interpolations and recommendations of the inputs. In the DF treatment, the inputs were applied according to the conventional fertilization methodology, a soil and leaf sample was with drawn from each plot and, based on the expected production, the input requirement was calculated. In the DV treatment, the samplings were georeferenced and carried out to each hectare. The recommendations for phosphorus, potassium, limestone, and nitrogen were calculated based on the previous year\'s productivity maps and the laboratory results of the samplings. The applications of P, K, and N of the DV treatment were not reduced when compared to the applications of DF treatment, but the applications in varied rates presented better efficiencies in the application. The medium values of P and K in soils differed statistically only in the years 2013/14 and 2014/15 and were higher in DV treatment. The productivity in the DV treatment was higher when compared to the treatment DF and in the comparisons between the years, in four harvests the DV treatment presented higher productivities, presenting increases of 26% of fruit production and around 2.74 t ha-1 on average in the six years evaluated.

Neste trabalho, a automação de um sistema de pulverização a taxa variada com injeção direta é apresentado. A automação do sistema de pulverização montado em uma bancada laboratorial estática foi baseado em um controlador programável com capacidade de tempo real. Os sistemas de pulverização com injeção direta possibilitam o uso de diferentes agroquímicos em uma mesma aplicação, e adicionalmente reduzem os impactos toxicológico e ambiental relacionados com o preparo e descarte da mistura de agroquímico e água. A automação deste sistema envolve o desenvolvimento de placas de interface, a modelagem do pulverizador e o controle das vazões. Um ambiente de simulação baseado no LabVIEW permitiu que os códigos fonte e as rotinas desenvolvidas fossem utilizadas diretamente no controlador programável, exigindo pouca ou nenhuma modificação. Para regular a vazão de injeção do agroquímico, que é dada por uma bomba de pistão, é utilizado um controlador proporcional-integral (PI). Já para regular a vazão da mistura de agroquímico e água, que é dada por uma válvula de controle proporcional de três vias, são implementados dois controladores: um controlador proporcional-integral-derivativo (PID) e um controlador adaptativo do tipo PID fuzzy por escalonamento de ganho. O desempenho dos controladores implementados são analisados via os resultados do erro de aplicação e das vazões. / In this work, the automation of a direct injection sprayer system for variable rate application of agrochemicals is presented. The automation of the sprayer system assembled on a laboratory static bench is based on a programmable controller with real time capabilities. Variable rate sprayer with direct injection systems allow multiple agrochemical application and additionally reduces the toxicologic and environmental risks associated with the carrier-agrochemical mix preparation and discard. The automation of this system comprises the development of interface boards, the sprayer modeling and the control of flow rates. Using a simulation environment based on LabVIEW, the developed source code and routines could be implemented directly in the programmable controller, requiring few or no changes. For the injection flow rate, which is set by a piston pump, a proportional-integral (PI) controller is used. And, to regulate the carrier-agrochemical mix flow rate, which is set by a three-way proportional control valve, two controllers are used: a proportional-integral-derivative (PID) controller and a fuzzy gain scheduling of PID controller. The performance of the implemented controllers is analyzed via the flow rates and the application error results.