Mit dem Begriff des eLearnings verknüpfen sich viele sehr unterschiedliche Konzepte, die auf Grund ihrer spezifischen Ausprägung häufig Grenzen für ihre Benutzung errichten. Um diese zu überwinden, wurde ein Framework konzipiert und implementiert, welches den Anspruch der Universalität in Hinblick auf Anwendungs- und Inhaltsorganisation sowie Funktionalität erhebt. In der kollaborativen eLearning-Plattform BluES erfuhr das Framework eine Beispielimplementierung. Diese diente gleichzeitig als Grundlage für die Validierung unterschiedlicher Aspekte des Frameworks. Als Ergebnis der Arbeit konnte gezeigt werden, dass maximale Flexibilität der Anwendung durch die Systemarchitektur gewährleistet werden kann. Dadurch werden Restriktionen in der Gestaltung der Anwendungsumgebung vermieden und die Anwender bei der Detailkonzeption ihrer Arbeit flexibel unterstützt.

A template tracker is a tracker based on matching a pre-initialised view of an object with the object's view in an image sequence. Using an error function, the intensity difference between the template view and the templated region in the image is measured. This error measure is used as the basis for a template alignment algorithm that will adjust the template's pose to more accurately register the template view with the view of the object in the image. Some significant problems present themselves with this simple tracker. Extraneous, or non-object, pixels within the template boundaries can cause bias in the registration of the template. Partial occlusions of the object's view in the image can also cause serious bias in the template's pose. Beyond simple occlusions there are transits of occlusions across an object. Occlusion transits are significant because over time they can occlude the entire object in an incremental fashion. If initially the template view is not completely known this kind of occlusion can easily cause a total tracking failure for an object. In this thesis three enhancements of the basic template tracker are proposed: Ownership Masks, Cooperative Templates, and Evolving Views. Ownership Masks are aimed at eliminating the extraneous pixels from the template view. Cooperative templates are used to separate the intensity probabilities when more than one template covers a pixel. Building upon both Ownership Masks and Cooperative Templates, Evolving Views update the template views when occlusion transits are a problem. With these enhancements we have been able to increase the accuracy of tracking objects where large portions of a template contain background pixels. Also occlusions and some types of unocclusions can be detected and discriminated. Finally, some failures in the basic tracker due to occlusion transits have been overcome.

Structure direction in the synthesis of phosphate-based materials (aluminophosphates, AlPOs; magnesiumaluminophosphates, MgAPOs; silicoaluminophosphates, SAPOs; magnesiumsilicoaluminophosphates, MgAPSOs), has been investigated through co-templating synthesis studies supported by molecular modelling. These solids have been characterised by diffraction and solid-state NMR, and their properties in gas adsorption and catalysis have been measured. The parameters in the hydrothermal synthesis of SAPO STA-7, St Andrews porous solid number 7, (SAV), in which the macrocycle 1,4,7,11- tetraazacyclotetradecane (cyclam) and tetraethylammonium (TEA) cations are used as co-templates, were investigated in detail. A new route involving a reversal of the mixing order of reagents leads to the formation of single crystals up to 50 μm with perfect tetragonal prismatic morphology that was not achieved via previous synthetic routes. For the first time in SAPO STA-7, X-ray diffraction locates the tetraethylammonium cation (TEA) in tg.tg. conformation. The synthesis and full characterisation of a novel aluminophosphate structure designated STA-14 (KFI) represents the first example of a designed synthesis of a zeotype. The synthesis route is based on a co-templating approach supported by molecular modelling to design the specific template for one of the two types of cages within the structure. The first, a larger type of cage, also present in AlPO-42 (LTA), is templated by the azaoxacryptand 4,7,13,16,21,41-diaza-1,10-bicyclo[8,8,8]- hexocosane (‘Kryptofix 222’, hereafter K222). The modelled co-template configuration, in this case TEA in the tt.tt configuration, was experimentally observed by X-ray diffraction. Modifying the gel chemistry leads to SAPO and MgAPSO STA-14, which display high pore volumes for N₂ adsorption, similar to those of STA-7 and SAPO-34 (CHA). Furthermore, during these synthetic studies, a novel fully tetrahedrally- coordinated magnesiumaluminophosphate layer phase has been prepared, with a structure of relevance to hypothetical VPI-5 (VFI) type extended structures. Molecular modelling was also applied in another aluminophosphate-based material, that of STA-2 (SAT), to predict a template that could be prepared from inexpensive reagents. Existing routes required the use of expensive quinuclidine as a precursor to the template 1,4-bisquinuclidinium butane. The template suggested by modelling, 1,4-diazabicyclo (2,2,2)octane butane (NC₆H₁₂N⁺-C₄H₈-⁺NC₆H₁₂N), labelled DABCO_C4, templated AlPO STA-2 successfully. Structure characterisation of the as- prepared form of AlPO STA-2 using X-ray synchrotron data suggest the formation of Al- OH-Al units to accommodate the positively-charged template within the neutral framework and a combination of ¹³C, ¹⁴N and ¹⁵N NMR studies have been used to give further details of the template environment in the cages. The gas adsorption behaviour of the stable materials STA-7, STA-14 and STA-2 was evaluated for CO₂. High pressure adsorption (0 to 40 bars) on STA-7 and STA-14 shows similar behaviour due to their structural and chemical similarities. The total uptake of CO₂ for SAPO STA-7 is less than for the zeolite NaX (FAU) (3.4 and 5.2 mmolg -1 respectively at 373 K and 12 bars) but the usable capacity for pressure swing adsorption technology (PSA) between 1 to 20 bar for STA-7 is twice the value for NaX. The affinity of adsorption towards CO₂ and its low uptake at 1 bar made SAPO STA-7 a desirable sorbent for PSA. The zeotype affinity of adsorption for different probe gases is different, CO₂ >> CH₄ > CO, to that for zeolite NaX CO₂ >> CO > CH₄. Low pressure CO₂ adsorption (0 to 1 bar) in STA-7, STA-14 and STA-2 at temperatures between 273 and 303 K demonstrates that the topology and therefore the total free pore volume accessible to the gas molecules is the most important factor in determining the uptake in these solids, but that the composition and distribution of the silicon cations within the framework also has an important effect. For example at 273 K and 1 bar, the uptake of the STA-2 framework in the SAPO form is ca. 2wt% higher than in the AlPO form, but compared with SAPO STA-7, the uptake due to pore volume limitations is 10wt% lower under same conditions. In addition, the high quality of the SAPO STA-7 crystals obtained by the new route made them suitable in collaborations for the direct observation of diffusion of methanol by interference microscopy (IFM) and the study of their crystal growth by combined atomic force microscopy (AFM) and high resolution scanning electron microscopy (HRSEM). The catalytic applications of the STA-7 and STA-14 for the methanol-to-olefins reaction (MTO) and the argon adsorption at 87 K were also performed collaboratively. The results are reported and discussed here in the light of their structure and composition.

In this study, template-based methods are used for the fabrication of various nanostructures such as nandots, nanorods, nanowires, nanotubes, and core-shell structures. Porous alumina membranes were employed as templates and metal nanostructures were synthesized in the templates by electrodeposition. By using lithography techniques, controlled patterned nanostructures were also fabricated on alumina templates. The magnetic properties of the various metal nanostructures were investigated. The pore size, interpore distance, and pore geometry highly affect magnetic properties of nanostructures grown in the templates. Hexagonally ordered porous alumina templates can be fabricated by two-step anodization. The pore diameters and interpore distances were readily controlled by appropriately changing anodization conditions and pore widening time. Alumina templates with various pore geometries were also successfully synthesized by changing applied voltage, increasing and decreasing, during a third anodization step. To understand magnetic properties of nanostructures with different aspect rations in the form of nanodots, nanorods, or nanowires, Fe nanostructures were fabricated in the templates by controlling of electrodeposition times. The coercivity of nanostructures increased with increasing aspect ratio. The anisotropy of the arrays was governed by the shape anisotropy of the magnetic objects with different aspect ratios. nanowires in mild-hard alumina and conventional alumina templates showed distinct differences in the squareness of hysteresis loops and coercivity both as a function of pore structure and magnetic component. Iron oxide nanotubes with a unique inner-surface were also fabricated by an electrodeposition method. β-FeOOH nanotubes were grown in alumina templates and transformed into hematite and magnetite structures during various heating processes. Hematite nanotubes are composed of small nanoparticles less than 20 nm diameters and the hysteresis loops and FC-ZFC curves show superparamagnetic properties without the Morin transition. In the case of magnetite nanotubes, which consist of slightly larger nanoparticles, hysteresis loops show ferromagnetism with weak coercivity at room temperature while FC-ZFC curves exhibit the Verwey transition at 125 K. For the patterning of nanowires, lithography techniques including nanosphere lithography and e-beam lithography were used. Nanosphere lithography used self-assembled PS spheres as a mask creates holes between spheres and the size of the holes is determined by the size and geometry of ordered PS spheres on the templates. This method can grow patterned nanowires arrays and also produce unique cup-shaped nanostructures with sizes ranging from micrometer down to several nanometers. E-beam lithography was also combined with template-based electrodeposition. Of these two lithographic methods, this one is the most powerful in the fabrication of patterned nanostructures with high aspect ratios. Various features and the sizes of patterned structures can be readily controlled. By the directing the pore diameters and interpore distances of the alumina template, the size and number of patterned nanowires are also adjustable.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2006. / Includes bibliographical references.

We describe a method for modeling object classes (such as faces) using 2D example images and an algorithm for matching a model to a novel image. The object class models are "learned'' from example images that we call prototypes. In addition to the images, the pixelwise correspondences between a reference prototype and each of the other prototypes must also be provided. Thus a model consists of a linear combination of prototypical shapes and textures. A stochastic gradient descent algorithm is used to match a model to a novel image by minimizing the error between the model and the novel image. Example models are shown as well as example matches to novel images. The robustness of the matching algorithm is also evaluated. The technique can be used for a number of applications including the computation of correspondence between novel images of a certain known class, object recognition, image synthesis and image compression.

The present thesis is focused on various methods of controlling electronic and geometrical structure of two-dimensional overlayers adsorbed on metal surfaces exemplified by graphene and hexagonal boron nitride (h-BN) grown on transition metal (TM) substrates. Combining synchrotron-radiation-based spectroscopic and various microscopic techniques with in situ sample preparation, we are able to trace the evolution of overlayer electronic and geometrical properties in overlayer/substrate systems, as well as changes of interfacial interaction in the latter.It is shown that hydrogen uptake by graphene/TM substrate strongly depends on the interfacial interaction between substrate and graphene, and on the geometrical structure of graphene. An energy gap opening in the electronic structure of graphene on TM substrates upon patterned adsorption of atomic species is demonstrated for the case of atomic oxygen adsorption on graphene/TM’s (≥0.35 eV for graphene/Ir(111)). A non-uniform character of adsorption in this case – patterned adsorption of atomic oxygen on graphene/Ir(111) due to the graphene height modulation is verified. A moderate oxidation of graphene/Ir(111) is found largely reversible. Contrary, oxidation of h-BN/Ir(111) results in replacing nitrogen atoms in the h-BN lattice with oxygen and irreversible formation of the B2O3 oxide-like structure.      Pronounced hole doping (p-doping) of graphene upon intercalation with active agents – halogens or halides – is demonstrated, the level of the doping is dependent on the agent electronegativity. Hole concentration in graphene on Ir(111) intercalated with Cl and Br/AlBr3 is as high as ~2×1013 cm-2 and ~9×1012 cm-2, respectively.     Unusual periodic wavy structures are reported for h-BN and graphene grown on Fe(110) surface. The h-BN monolayer on Fe(110) is periodically corrugated in a wavy fashion with an astonishing degree of long-range order, periodicity of 2.6 nm, and the corrugation amplitude of ~0.8 Å. The wavy pattern results from a strong chemical bonding between h-BN and Fe in combination with a lattice mismatch in either [11 ̅1] or [111 ̅] direction of the Fe(110) surface. Two primary orientations of h-BN on Fe(110) can be observed corresponding to the possible directions of lattice match between h-BN and Fe(110).     Chemical vapor deposition (CVD) formation of graphene on iron is a formidable task because of high carbon solubility in iron and pronounced reactivity of the latter, favoring iron carbide formation. However, growth of graphene on epitaxial iron films can be realized by CVD at relatively low temperatures, and the formation of carbides can be avoided in excess of the carbon-containing precursors. The resulting graphene monolayer creates a periodically corrugated pattern on Fe(110): it is modulated in one dimension forming long waves with a period of ~4 nm parallel to the [001] direction of the substrate, with an additional height modulation along the wave crests. The novel 1D templates based on h-BN and graphene adsorbed on iron can possibly find an application in 1D nanopatterning. The possibility for growing high-quality graphene on iron substrate can be useful for the low-cost industrial-scale graphene production.

No description available.

While many users have relatively general information needs, users who are familiar with a certain topic may have more specific or complex information needs. Such users already have some knowledge of a subject and its concepts, and they need to find information on a specific aspect of a certain entity, such as its cause, effect, and relationships between entities. To successfully resolve this kind of complex information needs, in our study, we investigated the effectiveness of topic-independent query templates as a tool for assisting users in articulating their information needs. A set of query templates, which were written in the form of fill-in-the-blanks was designed to represent general semantic relationships between concepts, such as cause-effect and problem-solution. To conduct the research, we designed a control interface with a single query textbox and an experimental interface with the query templates. A user study was performed with 30 users. Okapi information retrieval system was used to retrieve documents in response to the users’ queries. The analysis in this paper indicates that while users found the template-based query formulation less easy to use, the queries written using templates performed better than the queries written using the control interface with one query textbox. Our analysis of a group of users and some specific topics demonstrates that the experimental interface tended to help users create more detailed search queries and the users were able to think about different aspects of their complex information needs and fill in many templates. In the future, an interesting research direction would be to tune the templates, adapting them to users’ specific query requests and avoiding showing non-relevant templates to users by automatically selecting related templates from a larger set of templates.

While many users have relatively general information needs, users who are familiar with a certain topic may have more specific or complex information needs. Such users already have some knowledge of a subject and its concepts, and they need to find information on a specific aspect of a certain entity, such as its cause, effect, and relationships between entities. To successfully resolve this kind of complex information needs, in our study, we investigated the effectiveness of topic-independent query templates as a tool for assisting users in articulating their information needs. A set of query templates, which were written in the form of fill-in-the-blanks was designed to represent general semantic relationships between concepts, such as cause-effect and problem-solution. To conduct the research, we designed a control interface with a single query textbox and an experimental interface with the query templates. A user study was performed with 30 users. Okapi information retrieval system was used to retrieve documents in response to the users’ queries. The analysis in this paper indicates that while users found the template-based query formulation less easy to use, the queries written using templates performed better than the queries written using the control interface with one query textbox. Our analysis of a group of users and some specific topics demonstrates that the experimental interface tended to help users create more detailed search queries and the users were able to think about different aspects of their complex information needs and fill in many templates. In the future, an interesting research direction would be to tune the templates, adapting them to users’ specific query requests and avoiding showing non-relevant templates to users by automatically selecting related templates from a larger set of templates.