Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser och 1 bildbil.

Diss. (sammanfattning) Linköping : Univ., 2004. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 393-404).

Thesis (Ph. D.)--University of California, Santa Cruz, 1993. / Typescript. Includes bibliographical references (leaves 180-187).

Thesis (Ph. D.)--Miami University, Dept. of Botany, 2004. / Title from second page of PDF document. Includes bibliographical references (p.70-79).

The question of how shape is represented is of central interest to understanding visual processing in cortex. While tuning properties of the cells in early part of the ventral visual stream, thought to be responsible for object recognition in the primate, are comparatively well understood, several different theories have been proposed regarding tuning in higher visual areas, such as V4. We used the model of object recognition in cortex presented by Riesenhuber and Poggio (1999), where more complex shape tuning in higher layers is the result of combining afferent inputs tuned to simpler features, and compared the tuning properties of model units in intermediate layers to those of V4 neurons from the literature. In particular, we investigated the issue of shape representation in visual area V1 and V4 using oriented bars and various types of gratings (polar, hyperbolic, and Cartesian), as used in several physiology experiments. Our computational model was able to reproduce several physiological findings, such as the broadening distribution of the orientation bandwidths and the emergence of a bias toward non-Cartesian stimuli. Interestingly, the simulation results suggest that some V4 neurons receive input from afferents with spatially separated receptive fields, leading to experimentally testable predictions. However, the simulations also show that the stimulus set of Cartesian and non-Cartesian gratings is not sufficiently complex to probe shape tuning in higher areas, necessitating the use of more complex stimulus sets.

No description available.

During the past two decades, as internet has spread across the world, bringing people and businesses closer, e-commerce has been on a rapid expansion. To be a part of the expanding market, businesses have put a lot of effort to understand consumer behavior online, and to adapt. E-commerce differs drastically from traditional stores in the way that consumers are able to browse commercial web shops in search for the desired product, without outside influence. To understand how customers behave when purchasing a product, the Dewey model, customer buying process, is used. This process consists of five steps, which are: need recognition, information retrieval, information evaluation, buying decision and evaluation. However, within e-commerce, the web shops are the only platform where the business have the opportunity to affect the customers, as there are no salespersons to affect customers’ decisions as in traditional stores. As the web shop is platform for communication within e-commerce, it increases the importance for businesses to understand how their visitors react to features on their web shops. Visual features of websites, such as color and layout, can be crucial when a potential customer makes a purchase. The purpose of this study is to see how several visual features affect the purchasing behavior throughout Dewey’s model, customer buying process.The findings and analysis shows that some features are valued higher from each other, some are dependent on each other, and some are being taken for granted. First impression, product information and purchase methods, are among the crucial moments throughout the buying process. Our test conducted shows that the different features have different impact throughout the buying process.

Semiconductive metal oxides are of great importance in environmental remediation and electronics because of their ability to generate charge carriers when excited with appropriate energy. The electronic structure, light absorption and charge transport properties have made the transition metal oxides an attractive material as photocatalyst. Recently, facet-engineering by morphology control has been intensively studied as an efficient approach to further enhance their photocatalytic performance. However, various processing steps and post-treatments used in the preparation of facet-engineered particles may generate different surface active sites which may affect their photocatalysis. Moreover, many traditional techniques (PL, EPR and XPS) used for materials characterization (oxygen vacancy, hydroxyl group, cation, etc.) are not truly surface specific but analyzing a range from surface few layers to bulk. Accordingly, they can only provide very limited information on chemical states of the surface active features and their distribution among facets, causing difficulties to unambiguously correlate facet-dependent results with activity. As a result, this often leads to different interpretations amongst researchers during the past decades. As the publications of titanium and zinc ranked top two among studies of first row of transition oxides in the past decades, this thesis will firstly review on the disagreements generated among researchers when they correlated the performance of ZnO and TiO₂ with their facet activities based on traditional techniques. As there are shortcomings of these techniques in producing truly facet-dependent features, some results can be misleading and with no cross-literature comparison. To address these issues, we have developed a new technique "probe-molecule-assisted NMR" which allows a genuine differentiation of surface active sites from various facets. This surface-fingerprint technique has been demonstrated to provide both qualitative (chemical shift) and quantitative (peak intensity) information on the concentration and distribution of truly surface features among facets. In light of the new technique, this thesis will revisit the facet-dependent photocatalytic properties and shed light on these issues.