Browsing by Subject "Diversity"
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Item Open Access Bio-nanohybrids of quantum dots and photoproteins facilitating strong nonradiative energy transfer(Royal Society of Chemistry, 2013-05-21) Seker U.O.S.; Mutlugun, E.; Hernandez-Martinez, R. L.; Sharma, V. K.; Lesnyak, V.; Gaponik N.; Eychmuller, A.; Demir, Hilmi VolkanUtilization of light is crucial for the life cycle of many organisms. Also, many organisms can create light by utilizing chemical energy emerged from biochemical reactions. Being the most important structural units of the organisms, proteins play a vital role in the formation of light in the form of bioluminescence. Such photoproteins have been isolated and identified for a long time; the exact mechanism of their bioluminescence is well established. Here we show a biomimetic approach to build a photoprotein based excitonic nanoassembly model system using colloidal quantum dots (QDs) for a new bioluminescent couple to be utilized in biotechnological and photonic applications. We concentrated on the formation mechanism of nanohybrids using a kinetic and thermodynamic approach. Finally we propose a biosensing scheme with an ON/OFF switch using the QD-GFP hybrid. The QD-GFP hybrid system promises strong exciton-exciton coupling between the protein and the quantum dot at a high efficiency level, possessing enhanced capabilities of light harvesting, which may bring new technological opportunities to mimic biophotonic events.Item Open Access Diverse relevance feedback for time series with autoencoder based summarizations(IEEE Computer Society, 2018) Eravci, B.; Ferhatosmanoglu, H.We present a relevance feedback based browsing methodology using different representations for time series data. The outperforming representation type, e.g., among dual-tree complex wavelet transformation, Fourier, symbolic aggregate approximation (SAX), is learned based on user annotations of the presented query results with representation feedback. We present the use of autoencoder type neural networks to summarize time series or its representations into sparse vectors, which serves as another representation learned from the data. Experiments on 85 real data sets confirm that diversity in the result set increases precision, representation feedback incorporates item diversity and helps to identify the appropriate representation. The results also illustrate that the autoencoders can enhance the base representations, and achieve comparably accurate results with reduced data sizes.Item Open Access Diversity and novelty in information retrieval(ACM, 2013-07-08) Santos, R. L. T.; Castells, P.; Altıngövde, I. S.; Can, FazlıThis tutorial aims to provide a unifying account of current research on diversity and novelty in different IR domains, namely, in the context of search engines, recommender sys- tems, and data streams.Item Open Access Diversity and novelty in web search, recommender systems and data streams(Association for Computing Machinery, 2014-02) Santos, R. L. T.; Castells, P.; Altingovde, I. S.; Can, FazlıThis tutorial aims to provide a unifying account of current research on diversity and novelty in the domains of web search, recommender systems, and data stream processing.Item Open Access A front-page news-selection algorithm based on topic modelling using raw text(Sage Publications Ltd., 2015) Toroman, C.; Can, F.Front-page news selection is the task of finding important news articles in news aggregators. In this study, we examine news selection for public front pages using raw text, without any meta-attributes such as click counts. A novel algorithm is introduced by jointly considering the importance and diversity of selected news articles and the length of front pages. We estimate the importance of news, based on topic modelling, to provide the required diversity. Then we select important documents from important topics using a priority-based method that helps in fitting news content into the length of the front page. A user study is subsequently conducted to measure effectiveness and diversity, using our newly-generated annotation program. Annotation results show that up to seven of 10 news articles are important and up to nine of them are from different topics. Challenges in selecting public front-page news are addressed with an emphasis on future research.Item Open Access Minority rights regime in Turkey and the European regional organizations(Bilkent University, 2004) Soner, B. AliThis thesis examines the framework of minority rights in the context of Turkey and the European-regional organizations focusing on the ways of accommodating two interrelated dimensions of minority conditions: citizenship equality and ethno-cultural particularity. Due to fact that ideological discourse and practices of nation-state system have often conflated ^^citizenship” (statemembership) and ^‘nationality” (ethno-cultural membership), the possibility of developing genuine equality in ethno-culturally diverse circumstances has depended on the capacity to create a true reconciliation between citizenship equality and ethno-cultural particularity. This thesis affirmed that norms, principles, practices and instruments adopted in the European-regional organizations have largely reconciled citizenship equality and ethno-cultural diversity. The two concepts, however, have often excluded each other in the Turkish context where the principle of equality has usually been conflated with national uniformity while ethno-cultural diversity has frequently been associated with practices of inegalitarian treatment. It is only under the influence of EU integration that legal-political framework and practices of Turkish regime began to take substantive steps in the direction of reconciling citizenship equality with ethno-cultural, religious and linguistic particularities.Item Open Access Time delay estimation in cognitive radio systems(IEEE, 2009-12) Koçak, Fatih; Çelebi, H.; Gezici, Sinan; Qaraqe, K. A.; Arslan, H.; Poor, H. V.In cognitive radio systems, secondary users can utilize multiple dispersed bands that are not used by primary users. In this paper, time delay estimation of signals that occupy multiple dispersed bands is studied. First, theoretical limits on time delay estimation are reviewed. Then, two-step time delay estimators that provide trade-offs between computational complexity and performance are investigated. In addition, asymptotic optimality properties of the two-step time delay estimators are discussed. Finally, simulation results are presented to explain the theoretical results. © 2009 IEEE.Item Open Access Whole genome sequencing of Turkish genomes reveals functional private alleles and impact of genetic interactions with Europe, Asia and Africa(BioMed Central Ltd., 2014-11-07) Alkan C.; Kavak, P.; Somel, M.; Gokcumen, O.; Ugurlu, S.; Saygi, C.; Dal, E.; Bugra, K.; Güngör, T.; Sahinalp, S. C.; Özören, N.; Bekpen, C.Background: Turkey is a crossroads of major population movements throughout history and has been a hotspot of cultural interactions. Several studies have investigated the complex population history of Turkey through a limited set of genetic markers. However, to date, there have been no studies to assess the genetic variation at the whole genome level using whole genome sequencing. Here, we present whole genome sequences of 16 Turkish individuals resequenced at high coverage (32 × −48×). Results: We show that the genetic variation of the contemporary Turkish population clusters with South European populations, as expected, but also shows signatures of relatively recent contribution from ancestral East Asian populations. In addition, we document a significant enrichment of non-synonymous private alleles, consistent with recent observations in European populations. A number of variants associated with skin color and total cholesterol levels show frequency differentiation between the Turkish populations and European populations. Furthermore, we have analyzed the 17q21.31 inversion polymorphism region (MAPT locus) and found increased allele frequency of 31.25% for H1/H2 inversion polymorphism when compared to European populations that show about 25% of allele frequency. Conclusion: This study provides the first map of common genetic variation from 16 western Asian individuals and thus helps fill an important geographical gap in analyzing natural human variation and human migration. Our data will help develop population-specific experimental designs for studies investigating disease associations and demographic history in Turkey.Item Open Access λ-diverse nearest neighbors browsing for multidimensional data(Institute of Electrical and Electronics Engineers, 2013-03) Kucuktunc, O.; Ferhatosmanoglu, H.Traditional search methods try to obtain the most relevant information and rank it according to the degree of similarity to the queries. Diversity in query results is also preferred by a variety of applications since results very similar to each other cannot capture all aspects of the queried topic. In this paper, we focus on the -diverse k-nearest neighbor search problem on spatial and multidimensional data. Unlike the approach of diversifying query results in a postprocessing step, we naturally obtain diverse results with the proposed geometric and index-based methods. We first make an analogy with the concept of Natural Neighbors (NatN) and propose a natural neighbor-based method for 2D and 3D data and an incremental browsing algorithm based on Gabriel graphs for higher dimensional spaces. We then introduce a diverse browsing method based on the distance browsing feature of spatial index structures, such as R-trees. The algorithm maintains a Priority Queue with mindivdist of the objects depending on both relevancy and angular diversity and efficiently prunes nondiverse items and nodes. We experiment with a number of spatial and high-dimensional data sets, including Factual’s (http://www.factual.com/) US points-of-interest data set of 13M entries. On the experimental setup, the diverse browsing method is shown to be more efficient (regarding disk accesses) than k-NN search on R-trees, and more effective (regarding Maximal Marginal Relevance (MMR)) than the diverse nearest neighbor search techniques found in the literature.