97,374 research outputs found
A Blind Synchronous Multi-User DS-CDMA Equaliser With Partial Loading
No full textIn this paper, we propose a blind multiuser detection scheme in a direct sequence CDMA downlink scenario by means of a chip-level equaliser, which can be updated even if not all possible users are active, i.e. the system is partially loaded. The active synchronous users are separated by re-establishing orthogonality of their spreading sequences in a common chip-level equaliser. The adaptation algorithm is mainly based on a constant modulus (CM) criterion applied to the active users. The inactive codes in the system must be considered, for which we propose and compare three different methods: (i) a mean square error criterion for absent users, and a CM approach with (ii) zero modulus or (iii) the transmission of arbitrary signals with small code amplitude. For all three cases, stochastic gradient descent algorithms are derived. The proposed algorithms are analysed and compared through various simulations, which demonstrate the algorithms' convergence and BER performance
Blind Multi-User Equalisation for a Dispersive DS-CDMA Downlink under Carrier Frequency Offset Conditions
No full textWe address blind multiuser detection in a DS-CDMA downlink channel in the presence of carrier frequency offset. The synchronous users are separated by re-establishing orthogonality of their spreading sequences in a shared equaliser at the chip level. The adaptation algorithm is based on a constant modulus criterion of the various users, for which a stochastic gradient descent algorithm can be derived. We show that the resulting filtered-error filtered-regressor algorithm requires modifications in order to cope with carrier offset, and propose an combined blind multiuser equaliser with blind carrier frequency offset estimation. Simulations demonstrating the algorithm's convergence and BER performance are presented
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Blind Chip-Rate Multiuser Equalisation
No full textThis paper addresses blind multiuser detection in a DS-CDMA downlink channel. The synchronous users are separated by re-establishing orthogonality of their spreading sequences in a common chip-rate equaliser. The adaptation algorithm can be based either on a constant modulus (CMA) criterion of the various users, or on a decision directed (DD) scheme. In either case, a stochastic gradient descent algorithm will result, as derived, in a multiple error filtered-X LMS type approach, whereby the equaliser input to both the multichannel CMA or DD algorithm are replaced by spreading code filtered versions. Adaptation examples are given underlining some of the characteristics of the proposed algorithm
A filled organic crystal as a hybrid large-bandwidth optical waveguide
No full textA fluorescent hollow crystal of 9,10-dicyanoanthracene was filled with a perylene diimide derivative with complementary emissive features. The obtained crystal-in-crystal hybrid was used as a multiresponsive optical waveguide, which showed passive and active modes of light transduction and a bandwidth that extends from the visible to the infrared region
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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Expanding “Communities and Collections” in the K-State Research Exchange (K-REx) to benefit the K-State Community and Beyond
No full textKansas State University has used its institutional repository, the K-State Research Exchange (K-REx), to store and share its first year experience program, K-State First, and notably its common reading program, K-State First Book. We have done so with the aim that the accessibility and preservation of these documents ensures program stability, promotes engagement with first year programming, and provides the ability to foster growth,educational opportunities, and community building outside of K-State. Moving away from research concentrated repositories and taking a more holistic approach to scholarship, especially when realizing the pedagogical significance of collaborative campus programming, institutions can showcase, discover, preserve, and grow programs that shape campus communities and engagement.
This session will provide an overview of K-REx and spotlight the digital archive of the university’s first year experience program and common reading program, K-State First Book. We will discuss the benefits and challenges to expanding the purview of your repositories. We talkthrough the types of materials we decide to host in our repository and why we share what we do. We will also provide recommendations on new ways to evaluate what belongs in institutional repositories and how this diversity can benefit your program, your institution, the community, and others
Blind Chip-Rate Equalisation for DS-CDMA Downlink Receiver
No full textA dispersive channel in the DS-CDMA downlink destroys the orthogonality of the synchronous users' spreading sequences. In this paper, we aim to re-establish this orthogonality blindly by means of a common chip-level equaliser. The adaptation algorithm is based on a constant modulus criterion forcing the various user symbols onto a constant modulus, for which a stochastic gradient descent algorithm is derived. This algorithm is structurally similar to a multiple error filtered-X LMS type approach, whereby the equaliser input CM update is replaced by a spreading code filtered version. Various simulations demonstrating the algorithm's convergence and noise performance are presented
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