1,720,963 research outputs found
Novel Inter-Cell Interference Coordination Scheme Using Normalized Intended Energy Distribution Index with Low Computational Complexity
No full textArray Antenna with Suppressed Side Lobe Level for Millimeter-Wave Applications
No full textAs millimeter-wave(mm-wave) band is attracted for 5G. and autonomous driving technology, mm-wave band has become a commercial interest. In mm-wave radar applications, the suppression of the side lobe level has to he considered thoroughly. This paper proposes an array antenna structure that reduces the side lobe level by arranging the equal power divider in series from the uniform distribution structure. The beam patterns of the proposed 1x8 array antenna completely suppress the first side lobe. The level difference between a peak gain and side lobe level was 18.4dB. The proposed method provides an array antenna with low side lobe level for mm-wave radar applications such as motion sensing and security
Electromagnetic Interference Reduction Method from Handheld Resonant Magnetic Field Charger (HH-RMFC) for Electric Vehicle
No full text인지 무선 통신망에서 고속 페이딩을 고려한 순차 검출기의 최적 설계
No full text학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 2011.8, [ vi, 68 p. ]In this paper, we studied the cooperative sensing via sequential detection in cognitive radio networks. Efficient and reliable spectrum sensing plays a critical role in cognitive radio networks. This paper presents a cooperative sequential detection scheme to reduce the average sensing time that is required to reach a detection decision. In the scheme, each cognitive radio computes the log-likelihood ratio for its every measurement, and the base station sequentially accumulates these log-likelihood statistics and determines whether to stop making measurement. So far, most papers related to spectrum sensing in cognitive radio networks using sequential detection have ignored fading effect or assumed slow fading environments. These assumptions are inevitable to consider acquired raw samples by detector as independent and identically distributed samples during the sensing duration. The paper studies how to design the sequential detector in a robust manner in fast fading environments. In this case, the acquired samples are independent and not identically distributed. We propose an optimal independent and identical distribution (i.i.d.) approximation which has better performance than the conventional scheme using the generalized log-likelihood ratio (GLLR). One assumes both the signal and noise are gaussian distributed at each sample time.한국과학기술원 : 전기 및 전자공학과
인지 무선 통신망에서 비균일 샘플 분포의 확률적 해석을 고려한 우도비 기반 에너지 검출기 설계
No full text학위논문(박사) - 한국과학기술원 : 전기및전자공학부, 2016.2
,[xi, 146 p. :]The exponential growth of wireless data traffic urged the international wireless industries and academia to lay out a new wireless network standard which is 5G. It is generally believed that the future 5G network may need to be engineered to meet a multitude of stringent requirements in terms of cost, energy and spectral efficiency, number of connected devices and latency. Cognitive Radio (CR) is one of the promising techniques to meet these requirements by exploiting underutilized spectrum bands especially at microwave frequencies where there is a spectrum crunch. CR has applications ranging from the traditional cellular including the recent interesting LTE-U (LTE in Unlicensed band) technology to device-to-device (D2D) and vehicle-to-vehicle (V2V) communication systems via interweave, underlay and overlay dynamic spectrum access.
In this regard, spectrum sensing for primary user (PU) detection is a core concept of the CR networks for ensuring that CRs do not cause harmful interference to PU networks. This thesis basically considers mobile CRs, and for a wireless and mobile system design, it is very important to reflect the distinguishing features of mobile radio propagation. A wireless mobile channel is modeled as a time-varying communication path between two stations, such as from/to one terminal to/from another terminal.
Therefore, this thesis studies signal detection methods in cognitive radios based on both the well-known likelihood ratio test (LRT) and the sequential probability ratio test (SPRT) considering instantaneously non-identically distributed samples. Since, it is rather impractical to perform the ideal test that fully reflects such a change of a sample statistic, we used a practical detection method that optimally approximates the ideal log-likelihood ratio (LLR) with respect to its statistical mean.
In the LRT scenario, we derived closed form expressions for the detection threshold value and the sample size under given false alarm and missed detection constraints and we also found that there exists a nonnegligible performance gap between the ideal and practical tests, and the related experiments and theoretical analyses are also explored. Furthermore, we propose how to design a sequential detector in a robust manner to guarantee predefined false alarm and missed detection constraints for both the ideal and practical SPRTs.한국과학기술원 :전기및전자공학부
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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