1,721,083 research outputs found
Effect of simultaneous transmit and receive antennas on cooperative cognitive radio networks
No full textIn this paper, we address the performance improvement of cooperative cognitive radio networks (CCRNs) with secondary users exploiting multiple antennas in the multiple input multiple output (MIMO) scenario. In order to expand the region of achievable rate by enabling full-duplex communication between secondary users, we adopt simultaneous transmitting and receiving antennas for the secondary users. The link capacities of the proposed framework are analyzed under the assumption of full channel side information. It is shown through numerical evaluation that the proposed MIMO CCRN framework can provide a considerable performance gain over the conventional CCRN and conventional MIMO CCRN frameworks
Altered Gut Microbiota Composition in Rag1-deficient Mice Contributes to Modulating Homeostasis of Hematopoietic Stem and Progenitor Cells
No full textHematopoietic stem and progenitor cells (HSPCs) can produce all kind of blood lineage cells, and gut microbiota that consists of various species of microbe affects development and maturation of the host immune system including gut lymphoid cells and tissues. However, the effect of altered gut microbiota composition on homeostasis of HSPCs remains unclear. Here we show that compositional change of gut microbiota affects homeostasis of HSPCs using Rag1(-/-) mice which represent lymphopenic condition. The number and proportions of HSPCs in Rag1(-/-) mice are lower compared to those of wild types. However, the number and proportions of HSPCs in Rag1(-/-) mice are restored as the level of wild types through alteration of gut microbiota diversity via transferring feces from wild types. Gut microbiota composition of Rag1(-/-) mice treated with feces from wild types shows larger proportions of family Prevotellaceae and Helicobacterceae whereas lower proportions of family Lachnospiraceae compared to unmanipulated Rag1(-/-) mice. In conclusion, gut microbiota composition of lymphopenic Rag1(-/-) mice is different to that of wild type, which may lead to altered homeostasis of HSPCs.113Nsciekc
Likelihood ratio test for wideband spectrum sensing
No full textIn this paper, we propose a novel detection scheme of spectrum sensing for cognitive radio with multiple receive antennas operating over a wideband channel composed of a multitude of subbands. By taking the observations in all subbands into consideration in the likelihood ratio test for sensing a subband, the proposed scheme can provide better performance than other conventional schemes. It is shown through computer simulations that the proposed scheme can provide considerable performance gains over conventional schemes for wideband spectrum sensing
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
On the Identification and Generation of Discrete-Time Chaotic Systems with Recurrent Neural Networks
No full textWe address the identification and generation of the discrete-time chaotic system (DTCS) with a two-layered recurrent neural network (RNN). First, we propose an identification procedure of the DTCS in which the RNN is required to have less layers than in the conventional procedures. Next, based on Li-Yorke theorem, we propose a generation procedure which enables us to predict a range of chaotic behavior of the DTCS in advance. Simulation results demonstrate that the proposed identification procedure, employing the Levenberg-Marquardt algorithm and a two-layered RNN, requires lower computational complexity than the conventional identification procedures at comparable performance.
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
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