Genetic algorithms for feature selection and weighting

Abstract Automated techniques to optimise the retrieval of relevant cases in a CBR system are desirable as a way to reduce the expensive knowledge acquisition phase. This paper concentrates on feature selection methods that assist in indexing the case-base, and feature weighting methods that improve the similarity-based selection of relevant cases. Two main types of method are presented: filter methods use no feedback from the learning algorithm that will be applied; wrapper methods incorporate feedback and hence take account of learning bias. Wrapper methods based on Genetic Algorithms have been found to deliver the best results with a tablet design application, but these generic methods are flexible about the criterion to be optimised, and should be applicable to a wide variety of problems. Introduction The majority of CBR systems rely on a good case-base organisation, an effective index and a (possibly knowledge intensive) similarity matching to select cases, that can then be used to solve a problem, see Many CBR tools provide standard means of constructing indexes. Isoft's ReCall is typical in using a C4.5 [Quinlan 1993] generated decision tree, constructed from the cases in the case-base, as the index. However, induction algorithms like C4.5 apply a greedy selection approach and so the features used by the index are not always the optimal ones. This is a particular problem when the cases contain many features irrelevant to the problem solving The cases identified by the index are next ranked according to their similarity to the new problem. The simplest similarity metric is Euclidean distance between normalised feature vectors. However, a "useful" (from the point of view of solving a problem) similarity should take account of the relative importances of various features. Certainly in a situation where many features are irrelevant to the problem to be solved, a simple similarity measure is insufficient. This problem can be partially solved by identifying and removing irrelevant features as before. However, a more flexible method assigns weights to the features to indicate their relative importance to the problem solving. Although the selection of the relevant features can usually be done quite accurately by an expert, feature weighting can only be done approximately by an expert, often by categorising the relevance as one from a small set of possible degrees of relevance. Therefore, applying an automated algorithm to find feature weights is attractive. Section 2 reviews feature selection and weighting methods. Our tablet formulation problem domain is introduced in Section 3

Mastering the Master Space

Supersymmetric gauge theories have an important but perhaps under-appreciated notion of a master space, which controls the full moduli space. For world-volume theories of D-branes probing a Calabi-Yau singularity X the situation is particularly illustrative. In the case of one physical brane, the master space F is the space of F-terms and a particular quotient thereof is X itself. We study various properties of F which encode such physical quantities as Higgsing, BPS spectra, hidden global symmetries, etc. Using the plethystic program we also discuss what happens at higher number N of branes. This letter is a summary and some extensions of the key points of a longer companion paper arXiv:0801.1585.Comment: 10 pages, 1 Figur

Resilience and Leadership in Dangerous Contexts

Daniel B. Cnossen was born and raised in Topeka, growing up on a small farm. He spent his childhood reading, running, playing sports, and working on the farm. Cnossen enrolled in the United States Naval Academy in 1998. He had never before seen the ocean and did not know how to swim, but he asked his new friends at the academy to teach him; he would often skip lunch to spend time in the pool. Cnossen joined the Navy triathlon team to strengthen his swimming. By his senior year, he had been elected captain of the team, which he helped lead to a national championship. After graduation, he headed to San Diego to undergo training as a Navy SEAL. Cnossen served several tours overseas. On September 6, 2009, less than thirty-six hours on the ground in Kandahar, Afghanistan, he activated a landmine, losing both legs and suffering internal injuries. Lieutenant Cnossen is now back in the United States facing new challenges. He is doing so with the same dedication and enthusiasm that he used to surmount previous challenges. He is positive and appreciative of his friends and family, and he is happy to be alive. Described by some as stoic, Cnossen is seen by those who know him best as soft-spoken and humble. No one as full of curiosity, zest, and humor as he is could be described as stoic. As Cnossen began his rehabilitation, he noted that now he would be able to do even more pull-ups. While at the Walter Reed Army Medical Center, Cnossen and other troops were visited by President Barack Obama. As the president was leaving, he noticed a copy of War and Peace on Cnossen\u27s bedside table. The two men joked that merely lifting the book would be another form of physical therapy

Resilience and Leadership in Dangerous Contexts

Daniel B. Cnossen was born and raised in Topeka, growing up on a small farm. He spent his childhood reading, running, playing sports, and working on the farm. Cnossen enrolled in the United States Naval Academy in 1998. He had never before seen the ocean and did not know how to swim, but he asked his new friends at the academy to teach him; he would often skip lunch to spend time in the pool. Cnossen joined the Navy triathlon team to strengthen his swimming. By his senior year, he had been elected captain of the team, which he helped lead to a national championship. After graduation, he headed to San Diego to undergo training as a Navy SEAL. Cnossen served several tours overseas. On September 6, 2009, less than thirty-six hours on the ground in Kandahar, Afghanistan, he activated a landmine, losing both legs and suffering internal injuries. Lieutenant Cnossen is now back in the United States facing new challenges. He is doing so with the same dedication and enthusiasm that he used to surmount previous challenges. He is positive and appreciative of his friends and family, and he is happy to be alive. Described by some as stoic, Cnossen is seen by those who know him best as soft-spoken and humble. No one as full of curiosity, zest, and humor as he is could be described as stoic. As Cnossen began his rehabilitation, he noted that now he would be able to do even more pull-ups. While at the Walter Reed Army Medical Center, Cnossen and other troops were visited by President Barack Obama. As the president was leaving, he noticed a copy of War and Peace on Cnossen\u27s bedside table. The two men joked that merely lifting the book would be another form of physical therapy

Face-space: A unifying concept in face recognition research

The concept of a multidimensional psychological space, in which faces can be represented according to their perceived properties, is fundamental to the modern theorist in face processing. Yet the idea was not clearly expressed until 1991. The background that led to the development of face-space is explained, and its continuing influence on theories of face processing is discussed. Research that has explored the properties of the face-space and sought to understand caricature, including facial adaptation paradigms, is reviewed. Face-space as a theoretical framework for understanding the effect of ethnicity and the development of face recognition is evaluated. Finally, two applications of face-space in the forensic setting are discussed. From initially being presented as a model to explain distinctiveness, inversion, and the effect of ethnicity, face-space has become a central pillar in many aspects of face processing. It is currently being developed to help us understand adaptation effects with faces. While being in principle a simple concept, face-space has shaped, and continues to shape, our understanding of face perception

Surface Rupture and Slip Distribution of the Denali and Totschunda Faults

The 3 November 2002 Denali fault, Alaska, earthquake resulted in 341 km of surface rupture on the Susitna Glacier, Denali, and Totschunda faults. The rupture proceeded from west to east and began with a 48-km-long break on the previously unknown Susitna Glacier thrust fault. Slip on this thrust averaged about 4 m (Crone et al., 2004). Next came the principal surface break, along 226 km of the Denali fault, with average right-lateral offsets of 4.5–5.1 m and a maximum offset of 8.8 m near its eastern end. The Denali fault trace is commonly left stepping and north side up. About 99 km of the fault ruptured through glacier ice, where the trace orientation was commonly influenced by local ice fabric. Finally, slip transferred southeastward onto the Totschunda fault and continued for another 66 km where dextral offsets average 1.6–1.8 m. The transition from the Denali fault to the Totschunda fault occurs over a complex 25-km-long transfer zone of right-slip and normal fault traces. Three methods of calculating average surface slip all yield a moment magnitude of Mw 7.8, in very good agreement with the seismologically determined magnitude of M 7.9. A comparison of strong-motion inversions for moment release with our slip distribution shows they have a similar pattern. The locations of the two largest pulses of moment release correlate with the locations of increasing steps in the average values of observed slip. This suggests that slipdistribution data can be used to infer moment release along other active fault traces.PublishedS23–S52reserve

Evolving faces from principal components

A system that uses an underlying genetic algorithm to evolve faces in response to user selection is described. The descriptions of faces used by the system are derived from a statistical analysis of a set of faces. The faces used for generation are transformed to an average shape by defining locations around each face and morphing. The shape-free images and shape vectors are then separately subjected to principal components analysis. Novel faces are generated by recombining the image components ("eigenfaces") and then morphing their shape according to the principal components of the shape vectors ("eigenshapes"). The prototype system indicates that such statistical analysis of a set of faces can produce plausible, randomly generated photographic images

Structural factors and best practices in implementing a linkage to HIV care program using the ARTAS model

<p>Abstract</p> <p>Background</p> <p>Implementation of linkage to HIV care programs in the U.S. is poorly described in the literature despite the central role of these programs in delivering clients from HIV testing facilities to clinical care sites. Models demonstrating success in linking clients to HIV care from testing locations that do not have co-located medical care are especially needed.</p> <p>Methods</p> <p>Data from the Antiretroviral Treatment Access Studies-II project ('ARTAS-II') as well as site visit and project director reports were used to describe structural factors and best practices found in successful linkage to care programs. Successful programs were able to identify recently diagnosed HIV-positive persons and ensure that a high percentage of persons attended an initial HIV primary care provider visit within six months of enrolling in the linkage program.</p> <p>Results</p> <p>Eight categories of best practices are described, supplemented by examples from 5 of 10 ARTAS-II sites. These five sites highlighted in the best practices enrolled a total of 352 HIV+ clients and averaged 85% linked to care after six months. The other five grantees enrolled 274 clients and averaged 72% linked to care after six months. Sites with co-located HIV primary medical care services had higher linkage to care rates than non-co-located sites (87% vs. 73%). Five grantees continued linkage to care activities in some capacity after project funding ended.</p> <p>Conclusions</p> <p>With the push to expand HIV testing in all U.S. communities, implementation and evaluation of linkage to care programs is needed to maximize the benefits of expanded HIV testing efforts</p

Remarks on quiver gauge theories from open topological string theory

We study effective quiver gauge theories arising from a stack of D3-branes on certain Calabi-Yau singularities. Our point of view is a first principle approach via open topological string theory. This means that we construct the natural A-infinity-structure of open string amplitudes in the associated D-brane category. Then we show that it precisely reproduces the results of the method of brane tilings, without having to resort to any effective field theory computations. In particular, we prove a general and simple formula for effective superpotentials

On the geometry of C^3/D_27 and del Pezzo surfaces

We clarify some aspects of the geometry of a resolution of the orbifold X = C3/D_27, the noncompact complex manifold underlying the brane quiver standard model recently proposed by Verlinde and Wijnholt. We explicitly realize a map between X and the total space of the canonical bundle over a degree 1 quasi del Pezzo surface, thus defining a desingularization of X. Our analysis relys essentially on the relationship existing between the normalizer group of D_27 and the Hessian group and on the study of the behaviour of the Hesse pencil of plane cubic curves under the quotient.Comment: 23 pages, 5 figures, 2 tables. JHEP style. Added references. Corrected typos. Revised introduction, results unchanged