Detection and localization of emitters in the presence of multipath

Yön bulma işlemi kısaca DF (Direction Finding, Yön Bulma) veya AOA (Angle of Arrival, Geliş Açısı) olarak ifade edilmektedir. Antenler, alıcı, sayısal kart ve bilgisayardan oluşan sisteme de DF (Direction Finding, Yön Bulma) sistemi denmektedir. DF sistemi tek olarak sadece vericilerin yönünü tespit edebilmektedir. Eğer amaç vericilerinin konumunun belirlenmesi ise ortamda en az iki DF sistemi bulunması gerekmektedir. Bu çalışmada telsiz vericilerinin sayılarının ve yerlerinin tespiti için yeni bir yöntem önerilmiştir. Telsiz vericilerinin sayısının ve yerinin tespitinde MDL (Minimum Description Length, Minimum Tanımlama Uzunluğu) tabanlı ITC (Information Theoretic Criteria) algoritması ile önce ortamdaki yol sayısının daha sonra MUSIC (Multiple Signal Classification, Çoklu İşaret Sınıflandırma) algoritması ile vericilerin yönlerinin belirlenmesi önemli bir aşamadır. MUSIC spektrumundaki her bir tepe her bir yolun geliş açısına karşılık gelecektir. Fakat çoklu yansımalı ortamlarda bir vericiden birden fazla yoldan işaret yayılacağından DF için ek çalışmalar gerekecektir. MVBF (Minimum Variance Beamforming, Minimum Varyans Huzme Şekillendirme) huzme şekillendirme algoritması kullanılarak her yoldan gelen işaretlerin zaman ekseni verileri elde edilir ve aralarındaki korelasyon katsayıları hesaplanır. Bu korelasyon katsayıları kullanılarak işaretlerin aynı kaynaktan yayılıp yayılmadıklarına karar verilir. Böylece verici sayısı ve onların yönleri tespit edilmektedir. Performans analizleri gerçek zamanlı deneylerle elde edilerek sunulmaktadır. Önerilen tekniğin etkinlik testi, tam yansımasız oda içerisinde iki kaynaklı denemelerle gerçekleştirilmiştir. Dış ortamda da başarılı denemeler yapılmıştır.  Anahtar Kelimeler: DF, dizilim anten, huzme şekillendirme, yön tespit.Direction Finding (DF), or in other words, estimation of Angle of Arrival (AOA), has been an active research area since the beginning of the 20th century. DF has several application areas such as, military applications, GSM with improved channel capacity, localization of illegal transmitters such as TV and radio stations, or, of a mountaineer losing his/her path, in addition to spectrum monitoring.When multiple sources are incident on an antenna array simultaneously, classical DF methods, such as interferometry and Doppler cannot resolve these sources. An effective solution to the problem is to use high-resolution subspace-based algorithms. Multiple Signal Identification and Classification (MUSIC) is the most powerful and widely used subspace-based method. MUSIC is known to successfully resolve two or more sources if they are incoherent. However, in practice, signals often propagate in multipath environments. Thus, a source signal is incident on the array from many paths, which implies that coherent signals at different angles will be received by an array.For source localization with MUSIC in a multipath environment, it is critical to initially detect the number of incident paths. The simplest such algorithms are based on counting the smallest eigenvalues of the array covariance matrix. Information Theoretic Criteria (ITC) is advanced algorithm for path enumeration widely used, such as the Akaike Informatin Criteria (AIC) and Minimum Description Length (MDL). Just as in MUSIC, these ITC algorithms are also affected in a multipath environment. This is due to the fact that signal coherence in a multipath environment alters the eigenstructure of the sensor array's correlation matrix, which in turn affects the performance of both MUSIC and ITC. MDL was proposed for source enumeration in the presence of multipath and signal coherence. A recent solution proposed for the problem of signal coherence is the Spatial Smoothing (SS) preprocessing algorithm. SS essentially removes the effect of coherency between incoming signals in the eigen-structure of the correlation matrix. Therefore, source localization process involves the following steps: First, the array antenna output is processed to form a sample covariance matrix, then SS is applied to this matrix, after which the number of signals are estimated and finally, based on these, MUSIC is used to generate an angle spectrum.It is important to note that in a multipath environ-ment, ITC with spatial smoothing merely detects the number of paths, i.e., the signals originating from sources directly or incident from the reflectors, and then the MUSIC algorithm localizes all these signals in the angle/AOA pseudospectrum. In other words, ITC and/or the MUSIC-AOA pseudospectrum, indicate the number of paths and not the number of independent sources present in a multipath environment. This is a significant problem if the objective is to localize actual independent sources in a multipath environment.In this study, the minimum description length information-theoretic algorithm is used for the joint detection and localization of multiple RF transmitters in a multipath environment is to enumerate the number of paths and then to measure the angle of arrival of each path using an antenna array with a high resolution direction finding algorithm such as MUSIC. Those possible propagation paths are the angles corresponding to the peaks of the MUSIC pseudospectrum. Since more than one path may correspond to a single emitter source, further processing is required. The time domain signals of these paths are then extracted with minimum variance beamforming in order to estimate their corre-lation coefficients with each other. These correlation coefficients are used to decide whether or not these paths correspond to the same emitter. Hence, the number of emitters and their angle of arrivals are jointly estimated. Performance analysis of the method is presented via real-time laboratory experimentation and discussed in this paper. To demonstrate the effectiveness of the proposed technique, experiments with two sources are conducted in an anechoic test chamber.  Keywords: DF, direction finding, array antenna, beamforming, MVBF

The Intercultural Skills Graduates and Businesses in Europe Need Today

It was the aim of the two surveys with European graduates and employers respectively to investigate the importance of intercultural competencies and skills for student employability and business success for European enterprise, now and in the future. The two surveys gave important insights into key factors that support the development of intercultural skills and competencies for graduates and employers across four countries and five different European regions, as well as five distinct universities. Our analysis shows clearly that one of the most important factors is the key role of experience with, and exposure to, people from different cultural backgrounds. Both students and employers scored much higher on important intercultural competencies such as cultural empathy, cognitive flexibility, open-mindedness, and tolerance for ambiguity, if they had frequent interactions with people from other cultures. This was also true for speaking at least one or more foreign languages at an intermediate or advanced level. Foreign language competence is an important intercultural skill not only for communication but also an important way in which cultural empathy and cognitive flexibility are learned and trained. In line with these results, both students and employers who had more exposure to different cultures also felt there was more need to pay attention to intercultural issues and support the development of intercultural skills than those with less experience of different cultures. Furthermore, our results from both the student and the employer surveys seem to reflect differences between more urban/metropolitan centres and more rural areas with smaller towns. London and Bursa are the two largest cities and the most metropolitan areas in our sample with a more multicultural population, whereas Worcester and Leuven are both smaller cities and the regions with the least ethnic diversity. Halmstad falls somewhere in between with a similar size and ethnic composition of the city and region as Worcester and Leuven, but the university itself has a very multicultural and mature student body that is very similar to LSBU in central London. While we cannot directly influence these regional differences in urbanisation and multiculturalism it is certainly important to be aware of them

Topic tracking using chronological term ranking

Topic tracking (TT) is an important component of topic detection and tracking (TDT) applications. TT algorithms aim to determine all subsequent stories of a certain topic based on a small number of initial sample stories. We propose an alternative similarity measure based on chronological term ranking (CTR) concept to quantify the relatedness among news articles for topic tracking. The CTR approach is based on the fact that in general important issues are presented at the beginning of news articles. By following this observation we modify the traditional Okapi BM25 similarity measure using the CTR concept. Using a large standard test collection we show that our method provides a statistically significantly improvement with respect to the Okapi BM25 measure. The highly successful performance indicates that the approach can be used in real applications. © 2013 Springer-Verlag London

The Intercultural Skills Graduates and Businesses in Europe Need Today

This ERASMUS+ funded project, “Developing the cross-cultural skills of graduates in response to the needs of European enterprise”, is developed in response to recent research highlighting the importance of intercultural competencies for graduates wanting to work in Europe, the employers’ needs, and the intercultural competencies and skills higher education institutions provide. This project aims to develop the intercultural competencies of graduates in the EU by enhancing the quality and relevance of their knowledge and skills to enable them to be active professionals in the European working environment. Five Higher Education Institutions have participated in this study: University of Worcester (Project lead, UK), London South Bank University (UK), UC Leuven-Limburg (Belgium), Halmstad University (Sweden), and Bursa Uludağ University (Turkey). The diversity of these partners, their respective regional and national contexts, and their experience in working together with regional businesses are central to achieve the project aims. As the first output of the project, this report presents results based on two types of analysis methods and data collected from four European countries (UK, Sweden, Belgium, and Turkey). Firstly, two surveys and the quantitative analysis of data collected from 585 student surveys responses and 403 employer survey responses and secondly, on an analysis of qualitative data collected through 50 interviews with employees in European organizations and 50 interviews with students studying in European universities

GOPred: GO Molecular Function Prediction by Combined Classifiers

Functional protein annotation is an important matter for in vivo and in silico biology. Several computational methods have been proposed that make use of a wide range of features such as motifs, domains, homology, structure and physicochemical properties. There is no single method that performs best in all functional classification problems because information obtained using any of these features depends on the function to be assigned to the protein. In this study, we portray a novel approach that combines different methods to better represent protein function. First, we formulated the function annotation problem as a classification problem defined on 300 different Gene Ontology (GO) terms from molecular function aspect. We presented a method to form positive and negative training examples while taking into account the directed acyclic graph (DAG) structure and evidence codes of GO. We applied three different methods and their combinations. Results show that combining different methods improves prediction accuracy in most cases. The proposed method, GOPred, is available as an online computational annotation tool (http://kinaz.fen.bilkent.edu.tr/gopred)

Body mass index and age at natural menopause: an international pooled analysis of 11 prospective studies

Current evidence on the association between body mass index (BMI) and age at menopause remains unclear. We investigated the relationship between BMI and age at menopause using data from 11 prospective studies. A total of 24,196 women who experienced menopause after recruitment was included. Baseline BMI was categorised according to the WHO criteria. Age at menopause, confirmed by natural cessation of menses for ≥ 12 months, was categorised as < 45 years (early menopause), 45–49, 50–51 (reference category), 52–53, 54–55, and ≥ 56 years (late age at menopause). We used multinomial logistic regression models to estimate multivariable relative risk ratios (RRRs) and 95% confidence intervals (CI) for the associations between BMI and age at menopause. The mean (standard deviation) age at menopause was 51.4 (3.3) years, with 2.5% of the women having early and 8.1% late menopause. Compared with those with normal BMI (18.5–24.9 kg/m2), underweight women were at a higher risk of early menopause (RRR 2.15, 95% CI 1.50–3.06), while overweight (1.52, 1.31–1.77) and obese women (1.54, 1.18–2.01) were at increased risk of late menopause. Overweight and obesity were also significantly associated with around 20% increased risk of menopause at ages 52–53 and 54–55 years. We observed no association between underweight and late menopause. The risk of early menopause was higher among obese women albeit not significant (1.23, 0.89–1.71). Underweight women had over twice the risk of experiencing early menopause, while overweight and obese women had over 50% higher risk of experiencing late menopause

Reconciling the stratigraphy and depositional history of the Lycian orogen-top basins, SW Anatolia

Terrestrial fossil records from the SWAnatolian basins are crucial both for regional correlations and palaeoenvironmental reconstructions. By reassessing biostratigraphic constraints and incorporating new fossil data, we calibrated and reconstructed the late Neogene andQuaternary palaeoenvironments within a regional palaeogeographical framework. The culmination of the Taurides inSWAnatolia was followed by a regional crustal extension from the late Tortonian onwards that created a broad array of NE-trending orogen-top basins with synchronic associations of alluvial fan, fluvial and lacustrine deposits. The terrestrial basins are superimposed on the upper Burdigalian marine units with a c. 7 myr of hiatus that corresponds to a shift from regional shortening to extension. The initial infill of these basins is documented by a transition from marginal alluvial fans and axial fluvial systems into central shallow-perennial lakes coinciding with a climatic shift from warm/humid to arid conditions. The basal alluvial fan deposits abound in fossil macro-mammals of an early Turolian (MN11–12; late Tortonian) age. The Pliocene epoch in the region was punctuated by subhumid/humid conditions resulting in a rise of local base levels and expansion of lakes as evidenced by marsh-swamp deposits containing diverse fossilmammal assemblages indicating late Ruscinian (lateMN15; late Zanclean) ageWe are grateful for the support of the international bilateral project between The Scientific and Technological Research Council of Turkey (TUBITAK) and The Russian Scientific Foundation (RFBR) with grant a number of 111Y192. M.C.A. is grateful to the Turkish Academy of Sciences (TUBA) for a GEBIP (Young Scientist Award) grant. T.K. and S.M. are grateful to the Ege University Scientific Research Center for the TTM/002/2016 and TTM/001/2016 projects. M.C.A., H.A., S.M. and M.B. have obtained Martin and Temmick Fellowships at Naturalis Biodiversity Center (Leiden). F.A.D. is supported by a Mehmet Akif Ersoy University Scientific Research Grant. T.A.N. is supported by an Alexander-von-Humboldt Scholarship. L.H.O. received support from TUBITAK under the 2221 program for visiting scientists

Cardiac valve evaluation and adipokine levels in obese women treated with sibutramine [Sibutramin ile tedavi edilen obez kadinlarda kardiyak kapak degerlendirmesi ve adipokin düzeyleri]

PubMed ID: 20538557Objective: The aims of present study were 1) to evaluate cardiac valve characteristics, 2) to determine the plasma concentrations of fibrinogen, high sensitivity C-reactive protein (hsCRP), adiponectin, and tumor necrosis factor-? (TNF-?) in the obese women before and after 19 months sibutramine treatment in the obese women. Methods: Sixty obese women were enrolled in this prospective, randomized study. Thirty women received 10 mg once daily dose of sibutramine for 19 months. The rest of the obese women received 15 mg once daily dose of sibutramine for 19 months. All patients were evaluated with echocardiography. Plasma levels of adiponectin and TNF-? were measured by enzyme-linked immunosorbent assay (ELISA) and hsCRP by immunoturbimetric assay. Student paired and unpaired t tests were used to compare the 10 mg or 15 mg dose sibutramine effects either in groups or between the groups. Results: There were no signs of significant regurgitation or thickening of the mitral and aortic valves on echocardiographic evaluation performed after 19 months of treatment. Parameters of systolic function after 10 or 15 mg treatment were not different from pretreatment characteristics. Minimal tricuspid regurgitation was found in one (1/27) patient treated with 10 mg sibutramine after 19 months. Among obese patients treated with 15 mg sibutramine one patient (1/28) had minimal mitral valve regurgitation and 2 patients (2/28) had minimal aortic insufficiency. Stage II diastolic dysfunction in the 15 obese treated with 15 mg regressed to stage I diastolic dysfunction (50%). Stage II diastolic dysfunction in the 10 obese treated with 10 mg regressed to stage I diastolic dysfunction (33.3%). Mean levels of TNF-? (p=0.04), fibrinogen (p=0.03) and hsCRP (p=0.04)i decreased and adiponectin (p=0.03) levels increased in the obese treated with 10 mg sibutramine. Likewise, in the patients treated with 15 mg sibutramine, mean levels of TNF-? (p=0.01), fibrinogen (p= 0.02), and hsCRP (p= 0.04) decreased and adiponectin (p= 0.02) levels increased. Conclusion: Nineteen months of sibutramine treatment does not affect heart valve and systolic functions, however, diastolic dysfunction severity reduced with sibutramine treatment. Also In addition, mean levels of adiponectin, TNF-?, fibrinogen and hs- CRP change with 19 months sibutramine treatment. (Anadolu Kardiyol Derg 2010; 10: 226-32) © 2010 by AVES Yayincilik Ltd