114 research outputs found

    Spatial combination of sensor data deriving from mobile platforms for precision farming applications

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    This thesis combines optical sensors on a ground and on an aerial platform for field measurements in wheat, to identify nitrogen (N) levels, estimating biomass (BM) and predicting yield. The Multiplex Research (MP) fluorescence sensor was used for the first time in wheat. The individual objectives were: (i) Evaluation of different available sensors and sensor platforms used in Precision Farming (PF) to quantify the crop nutrition status, (ii) Acquisition of ground and aerial sensor data with two ground spectrometers, an aerial spectrometer and a ground fluorescence sensor, (iii) Development of effective post-processing methods for correction of the sensor data, (iv) Analysis and evaluation of the sensors with regard to the mapping of biomass, yield and nitrogen content in the plant, and (v) Yield simulation as a function of different sensor signals. This thesis contains three papers, published in international peer-reviewed journals. The first publication is a literature review on sensor platforms used in agricultural research. A subdivision of sensors and their applications was done, based on a detailed categorization model. It evaluates strengths and weaknesses, and discusses research results gathered with aerial and ground platforms with different sensors. Also, autonomous robots and swarm technologies suitable for PF tasks were reviewed. The second publication focuses on spectral and fluorescence sensors for BM, yield and N detection. The ground sensors were mounted on the Hohenheim research sensor platform Sensicle. A further spectrometer was installed in a fixed-wing Unmanned Aerial Vehicle (UAV). In this study, the sensors of the Sensicle and the UAV were used to determine plant characteristics and yield of three-year field trials at the research station Ihinger Hof, Renningen (Germany), an institution of the University of Hohenheim, Stuttgart (Germany). Winter wheat (Triticum aestivum L.) was sown on three research fields, with different N levels applied to each field. The measurements in the field were geo-referenced and logged with an absolute GPS accuracy of ±2.5 cm. The GPS data of the UAV was corrected based on the pitch and roll position of the UAV at each measurement. In the first step of the data analysis, raw data obtained from the sensors was post-processed and was converted into indices and ratios relating to plant characteristics. The converted ground sensor data were analysed, and the results of the correlations were interpreted related to the dependent variables (DV) BM weight, wheat yield and available N. The results showed significant positive correlations between the DVs and the Sensicle sensor data. For the third paper, the UAV sensor data was included into the evaluations. The UAV data analysis revealed low significant results for only one field in the year 2011. A multirotor UAV was considered as a more viable aerial platform, that allows for more precision and higher payload. Thereby, the ground sensors showed their strength at a close measuring distance to the plant and a smaller measurement footprint. The results of the two ground spectrometers showed significant positive correlations between yield and the indices from CropSpec, NDVI (Normalised Difference Vegetation Index) and REIP (Red-Edge Inflection Point). Also, FERARI and SFR (Simple Fluorescence Ratio) of the MP fluorescence sensor were chosen for the yield prediction model analysis. With the available N, CropSpec and REIP correlated significantly. The BM weight correlated with REIP even at a very early growing stage (Z 31), and with SAVI (Soil-Adjusted Vegetation Index) at ripening stage (Z 85). REIP, FERARI and SFR showed high correlations to the available N, especially in June and July. The ratios and signals of the MP sensor were highly significant compared to the BM weight above Z 85. Both ground spectrometers are suitable for data comparison and data combination with the active MP fluorescence sensor. Through a combination of fluorescence ratios and spectrometer indices, linear models for the prediction of wheat yield were generated, correlating significantly over the course of the vegetative period for research field Lammwirt (LW) in 2012. The best model for field LW in 2012 was selected for cross-validation with the measurements of the fields Inneres Täle (IT) and Riech (RI) in 2011 and 2012. However, it was not significant. By exchanging only one spectral index with a fluorescence ratio in a similar linear model, it showed significant correlations. This work successfully proves the combination of different sensor ratios and indices for the detection of plant characteristics, offering better and more robust predictions and quantifications of field parameters without employing destructive methods. The MP sensor proved to be universally applicable, showing significant correlations to the investigated characteristics such as BM weight, wheat yield and available N.Diese Arbeit kombiniert optische Sensoren auf einer Sensorplattform (SPF) am Boden und in der Luft bei Messungen in Weizen, um die Stickstoff-(N)-Werte zu identifizieren, während gleichzeitig die Biomasse (BM) geschätzt und der Ertrag vorhergesagt wird. Erstmals wurde hierfür der Fluoreszenzsensor Multiplex Research (MP) in Weizen eingesetzt. Die Ziele dieser Dissertation umfassen: (i) Bewertung verfügbarer Sensoren und SPF, die in der Präzisionslandwirtschaft zur Quantifizierung des Ernährungszustandes von Nutzpflanzen verwendet werden, (ii) Erfassung von Daten mit zwei Spektrometern am Boden, einem Spektrometer auf einem Modellflugzeug (UAV) und einem Fluoreszenzsensor am Boden, (iii) Erstellung effektiver Nachbearbeitungsmethoden für die Datenkorrektur, (iv) Analyse und Evaluation der Sensoren für die Abbildung der BM, des Ertrags und des N-Gehaltes in der Pflanze, und (v) Ertragssimulation als Funktion von Merkmalen unterschiedlicher Sensorsignale. Diese Arbeit enthält drei Artikel, die in international begutachteten Fachzeitschriften publiziert wurden. Die erste Veröffentlichung ist eine Literaturrecherche über SPF in der Agrarforschung. Ein detailliertes Kategorisierungsmodell wird für eine allgemeine Unterteilung der Sensoren und deren Anwendungsgebiete herangenommen, die Stärken und Schwächen bewertet, und die Forschungsergebnisse von Luft- und Bodenplattformen mit unterschiedlicher Sensorik diskutiert. Außerdem werden autonome Roboter und für landwirtschaftliche Aufgaben geeignete Schwarmtechnologien beschrieben. Die zweite Publikation fokussiert sich auf Spektral- und Fluoreszenzsensoren für die Erfassung von BM, Ertrag und N. In der Arbeit wurden die Bodensensoren auf der Hohenheimer Forschungs-SPF Sensicle und der Sensor auf dem UAV in dreijährigen Feldversuchen auf der Versuchsstation Ihinger Hof der Universität Hohenheim in Renningen für die Bestimmung von Pflanzenmerkmalen und des Ertrags eingesetzt. Auf drei Versuchsfeldern wurde Winterweizen ausgesät, und in einem randomisierten Versuchsdesign unterschiedliche N-Düngestufen angelegt. Die Sensormessungen im Feld wurden mit einer absoluten GPS Genauigkeit von ±2,5 cm verortet. Die GPS Daten des UAVs wurden mittels der Nick- und Rollposition lagekorrigiert. Im ersten Schritt der Datenanalyse wurden die Sensorrohdaten nachbearbeitet und in Indizes und Ratios umgerechnet. Die Bodensensordaten wurden analysiert, und die Ergebnisse der Korrelationen in Bezug zu den abhängigen Variablen (DV) BM-Gewicht, Weizenertrag, verfügbarer sowie aufgenommener N dargestellt. Die Ergebnisse zeigen signifikant positive Korrelationen zwischen den DVs und den Sensicle-Sensordaten. Für die dritte Publikation wurden die Sensordaten des UAV in die Auswertungen miteinbezogen. Die Analyse der UAV Daten zeigte niedrige signifikante Ergebnisse für nur ein Feld im Versuchsjahr 2011. Ein Multikopter wird als zuverlässigere Luftplattform erachtet, der mehr Präzision und eine höhere Nutzlast ermöglicht. Die Sensoren auf dem Sensicle zeigten ihren Vorteil bedingt durch einen kürzeren Messabstand zur Pflanze und eine kleinere Messfläche. Die Ergebnisse der beiden Sensicle-Spektrometer zeigten signifikant positive Korrelationen zwischen dem Ertrag und den Indizes von CropSpec, NDVI (Normalised Difference Vegetation Index) und REIP (Red-Edge Inflection Point). Auch FERARI und SFR (Simple Fluorescence Ratio) des MP-Sensors wurden für die Analyse des Ertragsvorhersagemodells ausgewählt. Mit dem verfügbaren N korrelierten CropSpec und REIP hochsignifikant. Das BM-Gewicht korrelierte bereits ab einem sehr frühen Wachstumsstadium (Z31) mit REIP und im Reifestadium (Z85) mit SAVI (Soil-Adjusted Vegetation Index). REIP, FERARI und SFR zeigten hohe Korrelationen mit dem verfügbaren N, insbesondere im Juni und Juli. Die Ratios und Signale des MP Sensors sind vor allem ab Z85 gegenüber dem BM-Gewicht hochsignifikant. Durch eine Kombination von Fluoreszenzwerten und Spektrometerindizes wurden lineare Modelle zur Vorhersage des Weizenertrags erstellt, die im Verlauf der Vegetationsperiode für das Versuchsfeld Lammwirt (LW) im Jahr 2012 signifikant korrelierten. Das beste Modell für das Feld LW im Jahr 2012 wurde für die Kreuzvalidierung mit den Messungen der Versuchsfelder Inneres Täle (IT) und Riech (RI) in den Jahren 2011 und 2012 ausgewählt. Sie waren nicht signifikant, jedoch zeigten sich durch den Austausch nur eines Spektralindexes mit einem Fluoreszenzratio in einem ähnlichen linearen Modell signifikante Korrelationen. Die vorliegende Arbeit zeigt erfolgreich, dass sich die Kombination verschiedener Sensorwerte und Sensorindizes zur Erkennung von Pflanzenmerkmalen gut eignet, und ohne den Einsatz destruktiver Methoden die Möglichkeit für bessere und robustere Vorhersagen bietet. Vor allem der MP-Fluoreszenzsensor erwies sich als universell einsetzbarer Sensor, der signifikante Korrelationen zu den untersuchten Merkmalen BM-Gewicht, Weizenertrag und verfügbarem N aufzeigte

    Optimization of historic buildings that house artefacts considering climate change

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    Historic buildings, and the artefacts that are usually kept within these buildings, are a living representation of the past and it is essential to ensure that future generations have access to this heritage. In order to accomplish this, it is necessary to determine the conditions that the buildings are in and, if needs be, to make the required changes in order to preserve our cultural heritage. In addition, the foreseen changes of the indoor climate caused by climate change can endanger the preservation of these artefacts, since they are prone to various types of decay depending on the existing indoor conditions. One way of counteracting these changes, is the application of passive retrofit measures. However, the guideline was that retrofit measures were hardly ever used in cultural heritage because they could cause the building to lose its authenticity. Nowadays, more and more cases of historic buildings are subject to this type of measures. Indeed, these measures can lead to positive outcomes, such as decreasing the energy consumption of the buildings or mitigating the effects of climate change, but the welfare of the cultural heritage must be ensured before these measured can be applied. Hence, the main aim of this thesis is to determine the potential of passive retrofit measures in mitigating the negative effects of climate change in the indoor climate of historic buildings, whilst accounting for the artefacts’ preservation requirements. For this reason, the indoor climate of a 13th century church in Lisbon was used to develop and validate a whole-building hygrothermal model. Then, the model was run using future weather files to determine the future indoor conditions, which were then assessed using a risk-based analysis and an adaptive thermal comfort model. Finally, the effects of the passive retrofit measures in the building’s energy consumption, the artefacts’ conservation metrics and the occupants’ thermal comfort were assessed. The future weather files were developed based on the methodology described in standard EN 15927-4 and in Skartveit and Olseth model, which divides the global radiation into its direct and diffuse components. In addition, a methodology that aims to make large-sized hygrothermal studies more time-efficient is also presented. This methodology was based in the studies developed in this thesis. It was shown that the conditions for the preservation of artefacts that are housed in historic buildings will worsen, especially in Mediterranean climates when compared to humid Continental and Oceanic climates. The tested retrofit measures can mitigate, up to a certain extent, the negative effects imposed by climate change in terms of artefacts’ conservation requirements. However, the Mediterranean climates do not have the same margin as the other tested climates. In addition, it was also shown that there is a positive outcome of implementing these measures in terms of energy saving potential. These savings will even be higher if these measures are combined with a more adequate relative humidity and temperature setpoint strategy.Os edifícios históricos, e os artefactos que geralmente são guardados no interior destes edifícios, são uma representação viva do passado e é fundamental garantir que as gerações futuras também têm acesso ao património cultural. Para isso, é necessário determinar as condições interiores destes edifícios e, se necessário, aplicar as alterações necessárias de forma a promover a preservação do património. Além disso, as mudanças expectáveis dos climas internos causadas pelas alterações climáticas podem pôr em risco a preservação destes artefactos, uma vez que estes são propensos a vários tipos de deterioração consoante as condições internas. Uma forma de combater as mudanças expectáveis do clima interior deste tipo de edifico é a aplicação de medidas de reabilitação passivas. No entanto, era prática comum a sua aplicação em edifícios históricos ser muito restrita, uma vez que podiam provocar a perda de autenticidade destes edifícios. Actualmente é cada vez mais usual a aplicação destas medidas, que podem ter resultados bastante positivos, como a diminuição do consumo de energia dos edifícios ou a mitigação dos efeitos das alterações climáticas. No entanto, é necessário garantir que o património não sofre danos com a sua aplicação. O principal objectivo desta tese é determinar o potencial de mitigação dos efeitos negativos impostos pelas alterações climáticas no clima interior de edifícios históricos através do recurso a medidas de reabilitação passivas, tendo em conta os requisitos de preservação dos artefactos. Por este motivo, o clima interno de uma igreja do século XIII em Lisboa foi utilizado para desenvolver e validar um modelo higrotérmico. Numa fase subsequente o modelo foi corrido para ficheiros climáticos futuros de forma a determinar as condições internas futuras, que foram avaliadas recorrendo a uma análise de risco e a um modelo de conforto térmico adaptável. Por fim, foi avaliado o efeito das medidas de reabilitação passivas no consumo de energia do edifício, nas métricas de conservação dos artefactos e no conforto térmico dos ocupantes do edifício. Os ficheiros climáticos futuros foram construídos com base na metodologia descrita na norma EN 15927-4 e no modelo Skartveit and Olseth, que permite subdividir a radiação global na componente directa e difusa. É também apresentada uma metodologia que visa tornar os estudos higrotérmicos com inúmeros casos mais eficiente em termos temporais. Esta metodologia baseou-se estudos desenvolvidos nesta tese de doutoramento. Ficou demonstrado que as condições de preservação de artefactos guardados no interior de edifícios históricos vão piorar, especialmente em climas mediterrâneos quando comparados com climas húmidos continentais e oceânicos. As medidas de reabilitação passivas testadas podem mitigar, até certo ponto, os efeitos negativos provocados pelas alterações climáticas em termos de conservação de artefactos. No entanto, os climas mediterrâneos não têm a mesma margem que os outros climas testados. Além disso, também foi demonstrado que a implementação destas medidas apresenta um resultado positivo em termos de poupança energética. No entanto, esta poupança será ainda maior se estas medidas forem combinadas com uma estratégia de controlo de temperatura e humidade relativa mais adequada

    Minulé a současné charakteristiky a formy vázané na permafrost a činnou vrstvu jako indikátory pozdně kvartérních změn přírodního prostředí

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    Late Quaternary has seen numerous major permafrost expansions and retreats associated with alternating glacial and interglacial periods as well as stadials and interstadials, the research of which is necessary to understand the past environmental evolution, but also provides useful analogues for its present-day and future behaviour. How- ever, observations of permafrost and active-layer phenomena are still limited, and sometimes misleading, even in many present-day permafrost regions, and naturally less comprehensive evidence is available from areas where permafrost existed in the past. The thesis provides comprehensive information on the distribution and morphology of mostly relict patterned ground and rock glaciers in the High Sudetes Mts. and in the Western and High Tatra Mts., respectively, which are the most widespread permafrost features that occur in these Central European mountain ranges situated north of the Alps. It shows that the landforms are closely related to increased severity of climates and/or sparser vegetation at higher elevations and as such they attest to the environmental conditions, which prevailed there towards the end of the Last Glacial Period to the early Holocene, but also to their current states. Similar elevation trends in the pattern morphology are also documented for...V pozdním kvartéru došlo v d̊usledku sťrídání glaciálních a interglaciálních období i stadiál̊u a interstadiál̊u k ̌cet- ným rozší̌rením a ústup̊um permafrostu, jehož výzkum je nezbytný pro pochopení vývoje p̌rírodního prosťredí v minulosti, ale poskytuje cenné informace i z hlediska jeho soǔcasné a budoucí dynamiky. Pozorování charak- teristik a forem vázaných na permafrost a ̌cinnou vrstvu jsou však stále nedostatěcná a ňekdy také zaváďející i v mnoha oblastech se soǔcasným výskytem permafrostu a mnohem méňe informací je k dispozici z region̊u, kde se permafrost nacházel v minulosti. Disertǎcní práce poskytuje ucelené informace o rozší̌rení a morfologii p̌revážňe reliktních strukturních p̊ud a kamenných ledovc̊u ve Vysokých Sudetech a Západních a Vysokých Tatrách, jež jsou nejrozší̌reňejšími formami vázanými na permafrost, které se v ťechto sťredoevropských pohǒrích severňe od Alp vyskytují. Je ukázáno, že tyto tvary reliéfu mají ťesnou vazbu na zvyšující se drsnost klimatických podmínek a ubývání vegetace sm̌erem do vyšších nadmǒrských výšek a jako takové sv̌eďcí o p̌rírodních podmínkách, které zde panovaly ke konci posled- ního glaciálu a na pǒcátku holocénu, jakož i o jejich soǔcasném stavu. Obdobné výškové trendy v morfologii struk- turních p̊ud jsou dokumentovány také pro...Department of Physical Geography and GeoecologyKatedra fyzické geografie a geoekologiePřírodovědecká fakultaFaculty of Scienc

    Students' empathy and classroom climate as predictors of attitudes towards immigrants: a case study in three EU countries

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    The development of positive attitudes towards immigrants among students can be addressed at the individual level through their empathic abilities and at the school or classroom level, where the classroom climate plays an important role.In the present study, we have taken a closer look into the relationship between attitudes towards immigrants, two components of empathy (perspective taking, empathic concern), quality of student-teacher relations (both positiveand negative) and inclusive classroom climate(presented as perceived intercultural sensitivity of teachers) in a sample of 814 8th-grade students in three EU countries (Slovenia, Croatia, and Sweden). The findings showonlyempathy (especially perspective taking) was associated with better attitudes towards immigrantsin all three countries. Additionally, in two out of three countries, the importance of the relationship with teachers and inclusiveclassroomclimate was important as well. The results are discussed in the light of guidelines for school practice

    Advanced Mobile Robotics: Volume 3

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    Mobile robotics is a challenging field with great potential. It covers disciplines including electrical engineering, mechanical engineering, computer science, cognitive science, and social science. It is essential to the design of automated robots, in combination with artificial intelligence, vision, and sensor technologies. Mobile robots are widely used for surveillance, guidance, transportation and entertainment tasks, as well as medical applications. This Special Issue intends to concentrate on recent developments concerning mobile robots and the research surrounding them to enhance studies on the fundamental problems observed in the robots. Various multidisciplinary approaches and integrative contributions including navigation, learning and adaptation, networked system, biologically inspired robots and cognitive methods are welcome contributions to this Special Issue, both from a research and an application perspective
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