Synopsis The thesis is concerned to cube solids and their use in primary school geometry. The main direction of the thesis is the development of children's spatial visualisation. The first part contains the explanation of key words in connected to spatial vizualization. I describe the environment of cube solids and work with them in various tasks. The second part includes records and analyses of my experiments, which were realized at two fourth grade classes within several months. First experiments were realized within regular lessons, later experiments in individual meetings. Analysing the experiments I identified and described several cognitive phenomena which I tried to explain in the conclusion.

The popularity of spatial databases increases since the amount of the spatial data that need to be handled has increased by the use of digital maps, images from satellites, video cameras, medical equipment, sensor networks, etc. Spatial data are difficult to examine and extract interesting knowledge / hence, applications that assist decision-making about spatial data like weather forecasting, traffic supervision, mobile communication, etc. have been introduced. In this thesis, more natural and precise knowledge from spatial data is generated by construction of fuzzy spatial data cube and extraction of fuzzy association rules from it in order to improve decision-making about spatial data. This involves an extensive research about spatial knowledge discovery and how fuzzy logic can be used to develop it. It is stated that incorporating fuzzy logic to spatial data cube construction necessitates a new method for aggregation of fuzzy spatial data. We illustrate how this method also enhances the meaning of fuzzy spatial generalization rules and fuzzy association rules with a case-study about weather pattern searching. This study contributes to spatial knowledge discovery by generating more understandable and interesting knowledge from spatial data by extending spatial generalization with fuzzy memberships, extending the spatial aggregation in spatial data cube construction by utilizing weighted measures, and generating fuzzy association rules from the constructed fuzzy spatial data cube.

Imaging modalities such as CT, MRI, and SPECT have had a tremendous impact on diagnosis and treatment planning. These imaging techniques have given doctors the capability to visualize 3D anatomy structures of human body and soft tissues while being non-invasive. Unfortunately, the 3D images produced by these modalities often have boundaries between the organs and soft tissues that are difficult to delineate due to low signal to noise ratios and other factors. Image segmentation is employed as a method for differentiating Regions of Interest in these images by creating artificial contours or boundaries in the images. There are many different techniques for performing segmentation and automating these methods is an active area of research, but currently there are no generalized methods for automatic segmentation due to the complexity of the problem. Therefore hand-segmentation is still widely used in the medical community and is the €œGold standard€� by which all other segmentation methods are measured. However, existing manual segmentation techniques have several drawbacks such as being time consuming, introduce slice interpolation errors when segmenting slice-by-slice, and are generally not reproducible. In this thesis, we present a novel semi-automated method for 3D hand-segmentation that uses mesh extraction and surface parameterization to project several 3D meshes to 2D plane . We hypothesize that allowing the user to better view the relationships between neighboring voxels will aid in delineating Regions of Interest resulting in reduced segmentation time, alleviating slice interpolation artifacts, and be more reproducible.

CubeSat development has seen a rise since the first launch in 2003 due to faster design process and low launch costs. It has played a vital role in providing access to space to small start-ups and academic organizations with low budgets. It has also enabled the testing of different upcoming technologies in space and has helped in providing hands-on experience to students taking part in design of such platforms. University of Pisa, in collaboration with SITAEL, has also taken an initiative to design and develop a CubeSat to test the FEEP thruster, design of which is presented in the thesis. A FEEP system was designed to fit within 1U dimensions and with a dry mass of approximately 820 grams. The system is based on slit emitter which provides an advantage over already available technologies in the market which uses needle emitters. Slit emitter scan achieve multiple Taylor cones without the need of clustering as used in needle emitters and also have a higher Thrust to Power Ratio. A propellant comparison was done considering all the properties required for an ideal propellant for a FEEP system. This comparison led to the selection of indium as working propellant which has an atomic mass of 114.8 u and a melting point of 156.6 °C. The FEEP system was designed keeping in mind easy assembling and modularity of thruster for ease in changing parts. The design consists of three different modules that are assembled separately and then joined together to complete the assembling of the system. The propellant tank, which also houses the emitter, has an internal volume of 32.75 cm3 and can hold approximately 240 grams of indium, which has a density of 7.31 g/cm3. During mission analysis, a 600km altitude orbit was proposed by analyzing the amount of propellant required for drag compensation and de-orbit maneuver at different altitudes with worst case values for ballistic coefficient and Thrust to Weight Ratio. At this altitude, the propellant requirement is 254.4 grams, 14.4 grams more than that of what can fit in the propellant tank of the designed thruster. However, both design of the system and mission analysis are ongoing processes and changes would be made in the future to either one or both to meet the requirements.

This thesis work presents an innovative solution for small satellite antennas by integrating slot antennas and solar cells on the same panel to save small satellite surface real estate and to replace deployed wire antennas for certain operational frequencies. The two main advantages of the proposed antenna are: 1) the antenna does not require an expensive deployment mechanism that is required by dipole antennas; 2) the antenna does not occupy as much valuable surface real estate as patch antennas. The antenna design is based on using the spacing between the solar cells to etch slots in these spaces to create radiating elements. The initial feasibility study shows it is realistic to design cavit-backed slot antennas directly on a solar panel of a cube satellite. Due to the volume of the satellite, it is convenient to design antennas at S band or higher frequencies. Although it is possible to design integrated solar panel antennas in lower frequencies, such research is not the scope of this thesis work. In order to demonstrate and validate the design method, three fully integrated solar panel antennas were prototyped using Printed Circuit Board (PCB) technology (PCB is a common solar panel material for small satellites). The first prototype is a circularly polarized antenna. The second is a linearly polarized two-element antenna array. The third prototype is a dual band linearly polarized antenna array. Measured results agree well with simulations performed using Ansoft's High Frequency Structure Simulater (HFSS). The thesis also presents a feasibility study of optimization methods and reconfigurable solar panel antenna arrays. The optimization study explores methods to use genetic algorithms to find optimal antenna geometry and location. The reconfigurable study focuses on achieving different antenna patterns by switching on and off the slot elements placed around the solar cells on solar panels of a cube satellite. It is shown that the proposed integrated solar panel antenna is a robust and cost-effective antenna solution for small satellites. It is also shown that given a solar panel with reasonable size, one can easily achieve multiple antenna patterns and polarization by simple switching.

Cube Satellite (CubeSat) launches have been on the rise since its first launch in2003. This popularity is mainly due to faster design process and lower launch costs.However, most CubeSats are launched into Low Earth Orbits (LEOs), with nomissions to Geostationary Transfer Orbits (GTOs). However, many mission areplanned for the next half-decade.A major challenge to launch a CubeSat into a GTO is the thermal environmentof the higher altitude orbits. These orbits are significantly colder due to reducedheating from Earth’s planetary and albedo radiations, and a possibility for longereclipses due to the eccentricities of GTOs.A thermal investigation of the thermal environment was done using the Foresailmissions as examples, as the missions currently are set to fly the first missions toPolar LEO. The trajectories for the second Foresail mission are being evaluated,with the GTO being a strong contender. This thermal investigation is done througha comparative study of the two missions. The thermal effects of a few missionspecific scenarios were also evaluated.This provided a holistic thermal design of the first Foresail mission. A region specificthermal solution for the battery was analyzed. The various mission scenarios andtheir comparisons with the LEO mission, also formed a basis of the feasibility ofvarious situations on the second mission. Moreover, the results, in part assessedthe thermally feasibility to launch a 3U CubeSat into a GTO.The results showed GTOs show larger magnitude of variation of thermal loads ascompared to LEOs. However, these variations are more gradual due to the largerorbital periods. A 3U CubeSat can be launched into both, the LEO and GTOenvironments with passive thermal control. The properties of the thermal coatsvary slightly. However, it is not possible to passively control the CubeSat if theeclipse occurred at the aphelion of the orbit.

Complex multidimensional capturing setups such as plenoptic cameras (PC) introduce a trade-off between various system properties. Consequently, established capturing properties, like image resolution, need to be described thoroughly for these systems. Therefore models and metrics that assist exploring and formulating this trade-off are highly beneficial for studying as well as designing of complex capturing systems. This work demonstrates the capability of our previously proposed sampling pattern cube (SPC) model to extract the lateral resolution for plenoptic capturing systems. The SPC carries both ray information as well as focal properties of the capturing system it models. The proposed operator extracts the lateral resolution from the SPC model throughout an arbitrary number of depth planes giving a depth-resolution profile. This operator utilizes focal properties of the capturing system as well as the geometrical distribution of the light containers which are the elements in the SPC model. We have validated the lateral resolution operator for different capturing setups by comparing the results with those from Monte Carlo numerical simulations based on the wave optics model. The lateral resolution predicted by the SPC model agrees with the results from the more complex wave optics model better than both the ray based model and our previously proposed lateral resolution operator. This agreement strengthens the conclusion that the SPC fills the gap between ray-based models and the real system performance, by including the focal information of the system as a model parameter. The SPC is proven a simple yet efficient model for extracting the lateral resolution as a high-level property of complex plenoptic capturing systems.

This study focused on the issue of paradigms in Human Resource Development (HRD). Its purpose was to validate the HRD Cube as a synthesized model of HRD and to explicate some of the extant paradigms of HRD. The study was carried out by examining the text of articles published in Academy of Human Resource Development (AHRD)-sponsored journals. Purposeful, stratified, and random sampling was used to select 16 articles published in AHRD-sponsored journals. Articles were treated as if they were the representative voice(s) of their author(s). Data units from within each article were identified and coded using two sequential techniques. First, units were axially coded and sorted into one of seven pre-determined categories based on the axioms of theory, research, and practice. Second, units were open coded using the constant comparative method, and themes and sub-themes were developed. Axial coding results identified a heavy emphasis on practice. The accumulation of units representing research and theory were comparatively smaller. Evidence of shared perspectives was found that emphasized the practice axiom. The accumulation of units emphasized research-practice, followed by theory-practice, and concluded with theory-research. Data units were also found that described all three axioms concurrently, theory-research-practice. Open coding results identified representative themes and sub-themes within each of the axiom-based categories of theory, research, and practice. Six themes developed in the theory category, 9 themes and 1 sub-theme developed in the research category, and 6 themes and 10 sub-themes developed in the practice category. The results provide evidence to support the overall construction of the HRD Cube. Theory, research, and practice perspectives of HRD were represented within the 16 articles used. The results also support the components described on each side of the HRD Cube. On the theory side, people, processes, and outcomes, and informing disciplines of HRD, were identified. Post-positive, interpretive, and critical epistemologies were identified on the research side. Individual, group, organizational, national, and global levels were identified on the practice side. Given the initial validation and support of the HRD Cube and of the components described within theory, research, and practice sides, within these 16 articles published in AHRD-sponsored journals, at least 18 prospective paradigms of HRD were identified.

Data warehouses contain data consolidated from several operational databases and provide the historical, and summarized data which is more appropriate for analysis than detail, individual records. On-Line Analytical Processing (OLAP) provides advanced analysis tools to extract information from data stored in a Data Warehouse. OLAP is designed to provide aggregate information that can be used to analyze the contents of databases and data warehouses. A range query applies an aggregation operation over all selected cells of an OLAP data cube where the selection is specified by providing ranges of values for numeric dimensions. Range sum queries are very useful in finding trends and in discovering relationships between attributes in the database. There is a method, prefix sum method, promises that any range sum query on a data cube can be answered in constant time by precomputing some auxiliary information. However, it is hampered by its update cost. For today's applications, interactive data analysis applications which provide current or "near current" information will require fast response time and have reasonable update time. Since the size of a data cube is exponential in the number of its dimensions, rebuilding the entire data cube can be very costly and is not realistic. To cope with this dynamic data cube problem, several strategies have been proposed. They all use specific data structures, which require extra storage cost, to response range sum query fast. For example, the double relative prefix sum method makes use of three components: a block prefix array, a relative overlay array and a relative prefix array to store auxiliary information. Although the double relative prefix sum method improves the update cost, it increases the query time. In the thesis, we present a method, called the recursive relative prefix sum method, which tries to provide a compromise between query and update cost. In the recursive relative prefix sum method with k levels, we use a relative prefix array and k relative overlay arrays. From our performance study, we show that the update cost of our method is always less than that of the prefix sum method. In most of cases, the update cost of our method is less than that of the relative prefix sum method. Moreover, in most of cases, the query cost of our method is less than that of the double relative prefix sum method. Compared with the dynamic data cube method, our method has lower storage cost and shorter query time. Consequently, our recursive relative prefix sum method has a reasonable response time for ad hoc range queries on the data cube, while at the same time, greatly reduces the update cost. In some applications, however, updating in some regions may happen more frequently than others. We also provide a solution, called the weighted relative prefix sum} method, for this situation. Therefore, this method can also provide a compromise between the range sum query cost and the update cost, when the update probabilities of different regions are considered.

Microresonators are devices that confine light in small volumes through total internal reflection. Introducing an emissive species into a microresonator allows for resonance enhanced emission at frequencies where the spectrum of the emissive species overlaps with the resonant frequencies of the microresonator. Previous research has led to a good understanding of these phenomena in 1D and 2D microresonators, but many 3D microresonator geometries have not yet been investigated. This work details the successful creation and demonstration of a cubic polymeric optical microresonator.