1,720,970 research outputs found
A Distributed And Spectrally Efficient Link Selection Scheme For Multiuser Multirelay Networks With Transmit Beamforming
No full textA distributed and spectrally efficient link selection scheme for multiuser multirelay cooperative networks with transmit beamforming is proposed and analyzed in terms of outage probability and mean spectral efficiency. More specifically, we consider a network composed by a base station equipped with M antennas which is communicating with one out of L single-antenna mobile stations under the aid of one out of N single-antenna, variable-gain amplify-and-forward relay stations. Either the direct link or the dual-hop relaying link is selected for each communication process by following a distributed link selection scheme. Single-integral expressions for upper and lower bounds of the outage probability and mean spectral efficiency are obtained and validated by Monte Carlo simulations. Furthermore, closed-form expressions derived from the asymptotic analysis of the outage probability reveal that the proposed system achieves full diversity order, which is equal to ML+N. Importantly, it is shown that the mean spectral efficiency is always higher than half of that one attained by direct transmission. © 2013 IEEE.13061310Yeoh, P.L., Elkashlan, M., Collings, I.B., Selection relaying with transmit beamforming: A comparison of fixed and variable gain relaying (2011) IEEE Trans. Commun., 59 (6), pp. 1720-1730. , JunDing, H., Ge, J., Da Costa, D.B., Jiang, Z., Link selection schemes for selection relaying systems with transmit beamforming: New and efficient proposals from a distributed concept (2012) IEEE Trans. Veh. Technol., 61 (2), pp. 533-552. , FebBeserra, M., Da Costa, D.B., An efficient relay-destination selection scheme for multiuser multirelay downlink cooperative networks (2012) IEEE Trans. Veh. Technol., 61 (5), pp. 2354-2360. , JunPapoullis, A., (2002) Probability, Random Variables, and Stochastic Processes, , 4th edition. McGraw-HillGradshteyn, I., Ryzhik, I., (2007) Table of Integrals, Series and Products, , 7th edition. Academic Pres
Distributed Suboptimal Schemes For Tas/sc And Tas/ls In Fixed-gain Af Relaying Systems
No full textWe design and analyze two distributed suboptimal schemes for transmit-antenna selection and link selection in a dual-hop, fixed-gain, amplify-and-forward relaying system, composed by one multi-antenna source, one single-antenna destination, and one single-antenna relay. The proposed schemes share the same antenna-selection policy, but differ from each other in the way the direct or relaying link is selected for communication. In a first scheme, the link is selected after transmission, at the destination; in a second scheme, it is selected before transmission, at the source. A great advantage of the proposed schemes over the optimal centralized solution is their low and constant delay/feedback overhead, regardless of the number of transmit antennas. In addition, the second scheme brings an improved spectral efficiency, once it saves one time slot when selecting the direct link. We derive analytical lower and upper bounds for the outage probability of the first scheme, in single-fold integral form, and exact closed-form expressions for the outage probability and mean spectral efficiency of the second scheme. We also perform an asymptotic analysis, showing that the first scheme achieves full diversity order, whereas the second scheme achieves full diversity order minus one, as a penalty for its improved spectral efficiency.131160416053Li, E., Yang, S., Wu, H., A source-relay selection scheme in two-way amplify-and-forward relaying networks (2012) IEEE Commun. Lett, 16 (10), pp. 1564-1567. , OctBao, V.N.Q., Phuong, B.P.L., Thanh, T.T., Performance analysis of TAS/SC-based MIMO decode-and-forward relaying for multi-hop transmission over Rayleigh fading channels (2012) Proc. ICCE, Santander, Spain, pp. 150-155. , Jul. 1-6Yeoh, P., Elkashlan, M., Yang, N., Da Costa, D.B., Duong, T., MIMO multi-relay networks with TAS/MRC and TAS/SC inWeibull fading channels (2012) Proc. IEEE Int. Symp. PIMRC, pp. 2314-2318. , Sydney, Australia, Sep. 9-12Suraweera, H., Smith, P., Nallanathan, A., Thompson, J., Amplify-andforward relaying with optimal and suboptimal transmit antenna selection (2011) IEEE Trans. Wireless Commun, 10 (6), pp. 1874-1885. , JunDing, H., Ge, J., Da Costa, D.B., Tsiftsis, T., A novel distributed antenna selection scheme for fixed-gain amplify-and-forward relaying systems (2012) IEEE Trans. Veh. Technol, 61 (6), pp. 2836-2842. , JulAmarasuriya, G., Tellambura, C., Ardakani, M., Performance analysis framework for transmit antenna selection strategies of cooperative MIMO AF relay networks (2011) IEEE Trans. Veh. Technol, 60 (7), pp. 3030-3044. , SepChen, Z., Yuan, J., Vucetic, B., Analysis of transmit antenna selection/maximal-ratio combining in Rayleigh fading channels (2005) IEEE Trans. Veh. Technol, 54 (4), pp. 1312-1321. , JulSimon, M.K., Alouini, M., (2000) Digital Communication over Fading Channels: A Unified Approach to Performance Analysis, , New York NY USA: WileyKaraevli, I.L., Altunbas, I., Karabulut Kurt, G., Performance analysis of cooperative relaying scheme applying TAS/SC (2010) Proc. ISCC, Riccione, pp. 127-132. , Italy, Jun 2-25Karaevli, I.L., Karabulut Kurt, G., Altunbas, I., Analysis of cooperative MIMO transmission system with transmit antenna selection and selection combining (2012) Wireless Commun. Mobile Comput, 12 (14), pp. 1266-1275. , OctYilmaz, A., Kucur, O., Performance of joint transmit and receive antenna selection in dual hop amplify-and-forward relay network over Nakagami-m fading channels (2014) Wireless Commun. Mobile Comput, 14 (1), pp. 103-114. , JanYilmaz, A., Kucur, O., End-to-end performance of transmit antenna selection and generalized selection combining in dual-hop amplify-andforward relay network in the presence of feedback errors (2014) Wireless Commun. Mobile Comput, 14 (7), pp. 689-703. , MaySanayei, S., Nosratinia, A., Antenna selection in MIMO systems (2004) IEEE Commun. Mag, 42 (10), pp. 68-73. , OctYeoh, P.L., Elkashlan, M., Collings, I., Selection relaying with transmit beamforming: A comparison of fixed and variable gain relaying (2011) IEEE Trans. Commun, 59 (6), pp. 1720-1730. , JunDing, H., Ge, J., Da Costa, D.B., Jiang, Z., Link selection schemes for selection relaying systems with transmit beamforming: New and efficient proposals from a distributed concept (2012) IEEE Trans. Veh. Technol, 61 (2), pp. 533-552. , FebDing, H., Ge, J., Da Costa, D.B., Jiang, Z., Diversity and coding gains of fixed-gain amplify-and-forward with partial relay selection in Nakagami-m fading (2010) IEEE Commun. Lett, 14 (8), pp. 734-736. , AugXu, F., Lau, F., Yue, D.-W., Diversity order for amplify-and-forward dual-hop systems with fixed-gain relay under Nakagami fading channels (2010) IEEE Trans. Wireless Commun, 9 (1), pp. 92-98. , JanGradshteyn, I.S., Ryzhik, M.I., (2007) Table of Integrals, Series, Products, , 7th ed San Diego, CA, USA: Academi
Outage Analysis Of A Spectrally Efficient Scheme For Multiuser Cognitive Relaying Networks With Spectrum Sharing Constraints
No full textThis paper investigates the outage performance of a spectrally efficient scheme for multiuser cognitive relaying networks under spectrum sharing constraints. In the proposed setup, we consider a secondary network composed by one source node communicating with the best one out of L available destinations, selected according to the channel quality of the direct links. If the selected direct link drops below a given threshold, a half-duplex decode-and-forward relaying transmission strategy is invoked, and then the selected secondary destination employs a maximal-ratio combining technique to combine the received signals from the secondary source and relay. In our analysis, the overall transmit power at the secondary network is considered to be limited by the maximum tolerable interference power at the primary user receiver, as well as by the maximum transmit power available at the secondary nodes. A closed-form expression for the outage probability is obtained and validated by Monte Carlo simulations. Moreover, an asymptotic analysis is carried out and reveals that the achievable diversity order equals L+1. © 2013 IEEE.9971001Mitola, J., Maguire, G.Q., Cognitive radio: Making software radios more personal (1999) IEEE Pers. Commun., 6 (4), pp. 13-18. , AugLanemann, J., Tse, D., Wornell, G., Cooperative diversity in wireless networks: Efficient protocols and outage behavior (2004) IEEE Trans. Inf. Theory, 50 (12), pp. 3062-3080. , DecYang, N., Elkashlan, M., Yuan, J., Outage probability of multiuser relay networks in nakagami-m fading channels (2010) IEEE Trans. Veh. Technol., 59 (5), pp. 2120-2132. , JunDing, H., Ge, J., Da Costa, D.B., Guo, Y., Spectrally efficient diversity exploitation schemes for downlink cooperative cellular networks (2012) IEEE Trans. Veh. Technol., 61 (1), pp. 386-393. , JanPapoullis, A., (2002) Probability, Random Variables, and Stochastic Processes, , 4th edition. McGraw-HillGradshteyn, I., Ryzhik, I., (2007) Table of Integrals, Series and Products, , 7th edition. Academic PressBletsas, A., Dimitriou, A., Sahalos, J., Interference-limited opportunistic relaying with reactive sensing (2010) IEEE Trans. Wireless Commun., 9 (1), pp. 14-20. , Ja
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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