Browsing by Subject "Alignment"
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Item Open Access Alignment of uncalibrated images for multi-view classification(IEEE, 2011) Arık, Sercan Ömer; Vuraf, E.; Frossard P.Efficient solutions for the classification of multi-view images can be built on graph-based algorithms when little information is known about the scene or cameras. Such methods typically require a pair-wise similarity measure between images, where a common choice is the Euclidean distance. However, the accuracy of the Euclidean distance as a similarity measure is restricted to cases where images are captured from nearby viewpoints. In settings with large transformations and viewpoint changes, alignment of images is necessary prior to distance computation. We propose a method for the registration of uncalibrated images that capture the same 3D scene or object. We model the depth map of the scene as an algebraic surface, which yields a warp model in the form of a rational function between image pairs. The warp model is computed by minimizing the registration error, where the registered image is a weighted combination of two images generated with two different warp functions estimated from feature matches and image intensity functions in order to provide robust registration. We demonstrate the flexibility of our alignment method by experimentation on several wide-baseline image pairs with arbitrary scene geometries and texture levels. Moreover, the results on multi-view image classification suggest that the proposed alignment method can be effectively used in graph-based classification algorithms for the computation of pairwise distances where it achieves significant improvements over distance computation without prior alignment. © 2011 IEEE.Item Open Access Changing alliance and cooperation dynamics : globalization, nation-state and the threat(Bilkent University, 2010) Çağlar, BarışThis dissertation is a study about the form and dynamics of inter-state cooperation and alignment against transnational terrorism epitomized by Al-Qaeda. Since international security is traditionally regarded as the parcel of nation-states, transnational terrorism is a conceptual new-comer to the playground of politics. Its scale of operations occurs in a security environment structurally different from that of the Cold War. The recurrent reason given for debating the role and relevance of alliances in regard to counterterrorism is discussed in the literature to be a systemic change in world affairs marked by the end of the Cold War and globalization. The latter must be disaggregated to determine the essential elements and features of the systemic differences and related threats. Does contemporary inter-state cooperation and alignment against transnational terrorism correspond to the previous alignment behaviors of states that were conducted against other states? Analyzing the evolving forms of cooperation in general and the form of cooperation in alliances is the aim of the study. Through a three-pronged analytical discussion based on the factors of globalization, unit-level preferences and the features of the threat itself, the study concludes that cooperation form in general and in alliances in particular - including the form of cooperation in NATO- is experiencing a shift from a ‘defensive nature’ to a ‘security nature’. Coalitions of the Willing type of cooperation appears to be the re-emergent form of inter-state security cooperation, especially against ambiguous threats such as transnational terrorism that erodes the distinction between internal and external threats.Item Open Access Detection of compound structures using hierarchical clustering of statistical and structural features(IEEE, 2011) Akçay, H. Gokhan; Aksoy, SelimWe describe a new procedure that combines statistical and structural characteristics of simple primitive objects to discover compound structures in images. The statistical information that is modeled using spectral, shape, and position data of individual objects, and structural information that is modeled in terms of spatial alignments of neighboring object groups are encoded in a graph structure that contains the primitive objects at its vertices, and the edges connect the potentially related objects. Experiments using WorldView-2 data show that hierarchical clustering of these vertices can find high-level compound structures that cannot be obtained using traditional techniques. © 2011 IEEE.Item Open Access Experimental and theoretical studies of transport through large scale, partially aligned arrays of single-walled carbon nanotubes in thin film type transistors(2007) Kocabas, C.; Pimparkar, N.; Yesilyurt O.; Kang, S.J.; Alam, M.A.; Rogers J.A.Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs grown by chemical vapor deposition with systematically varying degrees of alignment and coverage in transistors with a range of channel lengths and orientations perpendicular and parallel to the direction of alignment. A first principles stick-percolation-based transport model provides a simple, yet quantitative framework to interpret the sometimes counterintuitive transport parameters measured in these devices. The results highlight, for example, the dramatic influence of small degrees of SWNT misalignment on transistor performance and imply that coverage and alignment are correlated phenomena and therefore should be simultaneously optimized. The transport characteristics reflect heterogeneity in the underlying anisotropic metal-semiconductor stick-percolating network and cannot be reproduced by classical transport models. © 2007 American Chemical Society.Item Open Access Strategic alignment and new product development: drivers and performance effects(Wiley-Blackwell Publishing, 2012) Acur, N.; Kandemir, D.; Boer H.Strategic alignment is widely accepted as a prerequisite for a firm's success, but insight into the role of alignment in, and its impact on, the new product development (NPD) process and its performance is less well developed. Most publications on this topic either focus on one form of alignment or on one or a limited set of NPD performance indicators. Furthermore, different and occasionally contradictory findings have been reported. NPD scholars have long argued for the importance of fit between context and NPD activities. However, this body of literature suffers from the same weakness: most publications have a limited scope and the findings are not always consistent with results reported previously. This study addresses these deficiencies by examining (1) the effects of various internal and external factors on different forms of alignment, and (2) the effects of these forms of alignment on a set of NPD performance indicators. Strategic planning and innovativeness appear to affect technological, market, and NPD-marketing alignment positively. Environmental munificence is negatively associated with NPD-marketing alignment, but has no effect on the two other forms of alignment. Technological change has a positive effect on technological alignment, a negative effect on NPD-marketing alignment, but no effect on market alignment. These findings suggest that internal capabilities are more likely to be associated with the development of strategic alignment than environmental factors are. Furthermore, technological and NPD-marketing alignment affect NPD performance positively, while market alignment does not have any significant performance effects.