5,867 research outputs found
Beam Management for Millimeter Wave Beamspace MU-MIMO Systems
Millimeter wave (mmWave) communication has attracted increasing attention as
a promising technology for 5G networks. One of the key architectural features
of mmWave is the use of massive antenna arrays at both the transmitter and the
receiver sides. Therefore, by employing directional beamforming (BF), both
mmWave base stations (MBSs) and mmWave users (MUEs) are capable of supporting
multi-beam simultaneous transmissions. However, most researches have only
considered a single beam, which means that they do not make full potential of
mmWave. In this context, in order to improve the performance of short-range
indoor mmWave networks with multiple reflections, we investigate the challenges
and potential solutions of downlink multi-user multi-beam transmission, which
can be described as a high-dimensional (i.e., beamspace) multi-user
multiple-input multiple-output (MU-MIMO) technique, including multi-user BF
training, simultaneous users' grouping, and multi-user multibeam power
allocation. Furthermore, we present the theoretical and numerical results to
demonstrate that beamspace MU-MIMO compared with single beam transmission can
largely improve the rate performance of mmWave systems.Comment: The sixth IEEE/CIC International Conference on Communications in
China (ICCC2017
B\"acklund-Darboux Transformations and Discretizations of Super KdV Equation
For a generalized super KdV equation, three Darboux transformations and the
corresponding B\"acklund transformations are constructed. The compatibility of
these Darboux transformations leads to three discrete systems and their Lax
representations. The reduction of one of the B\"acklund-Darboux transformations
and the corresponding discrete system are considered for Kupershmidt's super
KdV equation. When all the odd variables vanish, a nonlinear superposition
formula is obtained for Levi's B\"acklund transformation for the KdV equation
A case study based inquiry into the adoption and adaptation of communicative language teaching in Chinese universities
The aim of this study is to investigate the extent to which Communicative Language Teaching (CLT) is adopted and/or adapted by Chinese tertiary teachers of English with the experience of teacher education overseas. It employs a case study approach in order to explore the extent to which CLT is compatible with the Chinese EFL context at tertiary level. Twenty-three informants in four institutions participated in this study (including two participating in the pilot study). Classroom observation and semi-structured interview were adopted as instruments for data collection. By looking into the teaching beliefs and actual practice of the target group, an attempt was made to reveal their general conceptions of CLT and their perceptions of good language teaching beyond CLT, as well as to identify the factors conceived as constraints on CLT implementation in the local context. In addition, through observation, an effort was made to explore the extent to which CLT was adopted and adapted in real teaching practice. Adjustments made by the participants to facilitate adoption of the approach were particularly focused on, as well as the extent to which intercultural experience contributed to effective teaching.
The main findings suggest that the CLT is seen as important by nearly all the informants in terms of its effectiveness and contributions, potential usefulness and complexity. Although constraints on CLT implementation were both mentioned and observed, âcommunicative ideasâ were found to be widely reflected in the teaching practice of the majority of the participants. The findings show that great attention is paid to learners as they are nowadays greatly involved in different teaching phases (pre-teaching, while-teaching and after-teaching). There exists a tendency of eclecticism in the teaching practices of many informants and the phenomenon of what is termed a âseeming-communicativeâ approach is reflected in some participantsâ ways of teaching due to a recognition of the fundamental importance of the learning skills of recitation and memorization. The experience of teacher education overseas is generally considered as conducive to enhancing practitionersâ intercultural competence and critical thinking -- two factors identified as essential prerequisites for CLT implementation and seeking of appropriate methodology. The findings give rise to discussion of three major problems in relation to interpreting CLT as an appropriate approach in Chinese EFL teaching context. These problems are essentialism, overgeneralization and labeling. The prevalence of these problems confirms that there is a need to understand CLT and its appropriateness in different cultural contexts from an anti-essentialist perspective
Exploring plannersâ facilitation styles in public participation : an inductive analysis
This thesis addresses the underexplored area of facilitation within public participation processes, particularly focusing on the strategic communication of the planners working as facilitators. Through inductive analysis with the help of grounded theory, this study developed a content analysis approach. It employs a set of analytical categories âfunctional element, turn, and episode âto track and make sense of both verbal and non-verbal actions of facilitators from a functional perspective. The research conducted a case study, reviewing the facilitation practice in public consultation of a large regional planning project in the United States. The results provided thick descriptions of facilitation styles and revealed various communicative characteristics in facilitation. This study proposes a preliminary categorization to describe and classify facilitation styles. In this categorization, different styles are categorized as variants with secondary characteristics under two primary types. Richness and complexity are introduced as new metrics to measure facilitatorsâ strategic communication. This tentative categorization, combined with the analytical categories, can be seen as a step toward a more nuanced classification of facilitation styles
Utilizing the Updated Gamma-Ray Bursts and Type Ia Supernovae to Constrain the Cardassian Expansion Model and Dark Energy
We update gamma-ray burst (GRB) luminosity relations among certain spectral
and light-curve features with 139 GRBs. The distance modulus of 82 GRBs at
can be calibrated with the sample at by using the cubic
spline interpolation method from the Union2.1 Type Ia supernovae (SNe Ia) set.
We investigate the joint constraints on the Cardassian expansion model and dark
energy with 580 Union2.1 SNe Ia sample () and 82 calibrated GRBs data
(). In CDM, we find that adding 82 high-\emph{z} GRBs to
580 SNe Ia significantly improves the constrain on
plane. In the Cardassian expansion model, the
best fit is and
, which is consistent with the CDM cosmology in the
confidence region. We also discuss two dark energy models in which
the equation of state is parametrized as and
, respectively. Based on our analysis, we see that our
Universe at higher redshift up to is consistent with the concordance
model within confidence level.Comment: 17 pages, 6 figures, 2 tables; accepted for publication in Advances
in Astronomy, special issue on Gamma-Ray Burst in Swift and Fermi Era. arXiv
admin note: text overlap with arXiv:0802.4262, arXiv:0706.0938 by other
author
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