305,977 research outputs found
Optimization of training signal transmission for estimating MIMO channel under antenna mutual coupling conditions
No full textThis paper reports investigations on the effect of antenna mutual coupling on performance of training-based Multiple-Input Multiple-Output (MIMO) channel estimation. The influence of mutual coupling is assessed for two training-based channel estimation methods, Scaled Least Square (SLS) and Minimum Mean Square Error (MMSE). It is shown that the accuracy of MIMO channel estimation is governed by the sum of eigenvalues of channel correlation matrix which in turn is influenced by the mutual coupling in transmitting and receiving array antennas. A water-filling-based procedure is proposed to optimize the training signal transmission to minimize the MIMO channel estimation errors. Copyright © 2010 X. Liu and M. E. Bialkowski
Effect of antenna mutual coupling on MIMO channel estimation and capacity
No full textinputmultiple- output (MIMO) wireless communication system. The presented investigations close the gap existing in the previous works which assessed the effect ofmutual coupling on MIMO capacity under the assumption of availability of perfect channel state information (CSI) at the receiver. The new approach assumes that the perfect CSI is not available due to channel estimation errors. The investigations are carried out for different spacing between array antenna elements producing a varying effect of mutual coupling on the channel estimation and the resulting MIMO channel capacity. Copyright © 2010 X. Liu and M. E. Bialkowski
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Finite Element Analysis Modeling of Pulse‐Laser Excited Photothermal Deflection (Mirage Effect)from Aerosols
No full textA finite element analysis method for numerical modeling of the photothermal deflection spectroscopy of aerosols is presented. The models simulate pulse-laser excited photothermal deflection from aerosols collected on a plane surface substrate in air medium. The influence of the aerosol and substrate properties on the transient photothermal deflection signal is examined. We have previously obtained experimental results for photothermal deflection spectrometry of aerosols deposited onto a plate from an impactor system (O. O. Dada and S. E. Bialkowski, Appl. Spectrosc. 62, 1336 (2008)). This paper supports the validity of the experimental results presented in that paper and helps in answering some of the questions raised. The modeling results presented here demonstrate that the (peak) normalized transient temperature change profile and (peak) normalized transient photothermal deflection profile are a good approximation and invariant with number of particles, inter-particle distance, and particulate shape, which suggests that the photothermal deflection signal amplitude may be calibrated linearly with total mass of aerosols and the method could be applied to analysis of complex aerosols
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