1,928 research outputs found
Rank-Two Beamforming and Power Allocation in Multicasting Relay Networks
In this paper, we propose a novel single-group multicasting relay beamforming
scheme. We assume a source that transmits common messages via multiple
amplify-and-forward relays to multiple destinations. To increase the number of
degrees of freedom in the beamforming design, the relays process two received
signals jointly and transmit the Alamouti space-time block code over two
different beams. Furthermore, in contrast to the existing relay multicasting
scheme of the literature, we take into account the direct links from the source
to the destinations. We aim to maximize the lowest received quality-of-service
by choosing the proper relay weights and the ideal distribution of the power
resources in the network. To solve the corresponding optimization problem, we
propose an iterative algorithm which solves sequences of convex approximations
of the original non-convex optimization problem. Simulation results demonstrate
significant performance improvements of the proposed methods as compared with
the existing relay multicasting scheme of the literature and an algorithm based
on the popular semidefinite relaxation technique
CRM adoption and its impact on organisational performance
Customer Relationship Management (CRM) which aims at enabling organisations to realize a customer focus is believed to be useful and has risen to the agenda of many organisational strategies. It can be seen as an approach to marketing that has its origins in Relationship Marketing (RM). In Hong Kong, CRM has been gathering attention from attorneys, accountants, merchants, bankers and financial advisors. However, there are few studies specifically investigating the factors that may influence the adoption of CRM. In order to bridge the gap in understanding, an exploratory study utilising in-depth interviews was conducted. A conceptual model was developed in order to deal with the two major objectives in this research 1) to investigate the factors which lead organisations to adopt CRM; and 2) the impact of CRM on the organisational performance. The conceptual model was tested with the relevant hypotheses, using a survey method by mailing questionnaires to the organisations of services industry in Hong Kong. Important findings from the examination of research objectives were discussed with regard to their implications for researchers and practitioners. Analysis results supported that attributes of innovation proposed by Rogers’ (1995), attitude towards change, market orientation, innovation orientation, perceived accessibility of IT solutions, competition intensity and desire of customer intimacy were the antecedents of CRM adoption. Also, it was discovered that information utilisation would be a possible mediator between CRM adoption and the performance. Finally, customer satisfaction, employee satisfaction and business performance was found to be influenced by CRM adoption. Limitations of study were reported together with recommendations for future research programmes
General Rank Multiuser Downlink Beamforming With Shaping Constraints Using Real-valued OSTBC
In this paper we consider optimal multiuser downlink beamforming in the
presence of a massive number of arbitrary quadratic shaping constraints. We
combine beamforming with full-rate high dimensional real-valued orthogonal
space time block coding (OSTBC) to increase the number of beamforming weight
vectors and associated degrees of freedom in the beamformer design. The
original multi-constraint beamforming problem is converted into a convex
optimization problem using semidefinite relaxation (SDR) which can be solved
efficiently. In contrast to conventional (rank-one) beamforming approaches in
which an optimal beamforming solution can be obtained only when the SDR
solution (after rank reduction) exhibits the rank-one property, in our approach
optimality is guaranteed when a rank of eight is not exceeded. We show that our
approach can incorporate up to 79 additional shaping constraints for which an
optimal beamforming solution is guaranteed as compared to a maximum of two
additional constraints that bound the conventional rank-one downlink
beamforming designs. Simulation results demonstrate the flexibility of our
proposed beamformer design
CRM adoption and its impact on organisational performance
Customer Relationship Management (CRM) which aims at enabling organisations to realize a customer focus is believed to be useful and has risen to the agenda of many organisational strategies. It can be seen as an approach to marketing that has its origins in Relationship Marketing (RM). In Hong Kong, CRM has been gathering attention from attorneys, accountants, merchants, bankers and financial advisors. However, there are few studies specifically investigating the factors that may influence the adoption of CRM. In order to bridge the gap in understanding, an exploratory study utilising in-depth interviews was conducted. A conceptual model was developed in order to deal with the two major objectives in this research 1) to investigate the factors which lead organisations to adopt CRM; and 2) the impact of CRM on the organisational performance. The conceptual model was tested with the relevant hypotheses, using a survey method by mailing questionnaires to the organisations of services industry in Hong Kong. Important findings from the examination of research objectives were discussed with regard to their implications for researchers and practitioners. Analysis results supported that attributes of innovation proposed by Rogers’ (1995), attitude towards change, market orientation, innovation orientation, perceived accessibility of IT solutions, competition intensity and desire of customer intimacy were the antecedents of CRM adoption. Also, it was discovered that information utilisation would be a possible mediator between CRM adoption and the performance. Finally, customer satisfaction, employee satisfaction and business performance was found to be influenced by CRM adoption. Limitations of study were reported together with recommendations for future research programmes
Teacher empowerment : an interpretive study of the experience of Asian migrant teachers in Western Australia
This research was prompted by arguments about the importance of empowerment in professional praxis of school practitioners and related legislations, namely, the Better Schools’ reform in 1987 and the WA Charter of Multiculturalism in 2004, and by persistent feelings of disempowerment and inefficacy I had experienced as an Asian migrant school practitioner in WA Government schools. Attributing cause to others is always easier than looking to ourselves for the root of our problems. Guided by the innovative concept of a research multi-paradigmatic design space, I adapted methods from the interpretivist-constructivist and critical paradigms, and embarked on a process of critical self-reflection aimed at gaining an understanding of my feelings of disempowerment and inefficacy.Complementing this autoethnographic study, selfreflections of three other Asian migrant school practitioners were included to gauge the degree of consonance of feelings amongst us as I shared my lived experience with them. The sharing of our experiences over a four-year period revealed that lack of respect and support from key stakeholders of the school system had been one of the root causes of our negative feelings, and that this perception was related to cultural dissonance between our collectivist Asian culture and the more individualistic culture of WA school communities.A natural response to the findings was a search for ways of minimizing the cultural dissonance. This research is as much a self-initiated change as a ‘political outreach’ aimed at instigating further discussion and debate as a catalyst for system-wide policy initiative to address the issue of cultural dissonance which is considered to be a key to reducing of feelings of disempowerment and inefficacy amongst Asian migrant teachers in WA Government schools. This research has been an emancipating and enlightening personal experience but it was not without limitations and problems
microRNA-133α regulates neurotensin-associated colonic inflammation in colonic epithelial cells and experimental colitis
Inflammatory Bowel Disease (IBD), which includes ulcerative colitis (UC) and Crohn’s Disease (CD), are gastrointestinal disorders characterized by chronic and persistent inflammation. Neurotensin (NT), together with its high-affinity receptor NT receptor 1 (NTR1) are important mediators in intestinal inflammation and their expression is increased in the intestine of experimental colitis models and UC colonic biopsies. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNA molecules which act as negative transcription regulators. We have previously shown that NT exposure upregulates miR-133α expression in human colonic epithelial NCM460 cells overexpressing NTR1 (NCM460-NTR1). Recently, we have further investigated the role of miR-133α in regulation of NT-associated proinflammatory signaling cascades and acute colitis in vivo. Our study shows that NT-induced miR-133α upregulation lead to NF-κB activation and increased production of proinflammatory cytokines. In addition, intracolonic administration of antisense-miR-133α prior to colitis induction improves histological scores and proinflammatory cytokine production. More importantly, dysregulation of miR-133α levels and aftiphilin (AFTPH), a novel miR-133α downstream target, are found only in patients with UC patients, but not with CD. Taken together, we have identified NTR1/miR-133α/aftiphilin as a novel regulatory axis involved in NT-associated colonic inflammation in vitro and in vivo. Our results also provide evidence that colonic levels of NTR1, miR-133a and aftiphilin may also serve as potential biomarkers in UC
The analytic radial acceleration relation for galaxy clusters
Recently, a tight correlation between the dynamical radial acceleration and
the baryonic radial acceleration in galaxies - the radial acceleration relation
- has been discovered. This has been claimed as an indirect support of the
modified gravity theories. However, whether the radial acceleration relation
could also be found in galaxy clusters is controversial. In this article, we
derive and present an analytic radial acceleration relation for the central
region of galaxy clusters. We examine the data of some large galaxy clusters
and we find that the resulting radial acceleration relation has a very large
scatter. Moreover, although the radial acceleration relation for galaxy
clusters shows some agreement with the one discovered in galaxies for a certain
range of baryonic radial acceleration, their functional forms are somewhat
different from each other. This suggests that the radial acceleration relation
may not be a universal relation in general.Comment: Accepted in Phys. Rev.
A severe challenge to the MOND phenomenology in our Galaxy
Modified Newtonian Dynamics (MOND) is one of the most popular alternative
theories of dark matter to explain the missing mass problem in galaxies.
Although it remains controversial regarding MOND as a fundamental theory, MOND
phenomenology has been shown to widely apply in different galaxies, which gives
challenges to the standard cold dark matter model. In this article,
we derive analytically the galactic rotation curve gradient in the MOND
framework and present a rigorous analysis to examine the MOND phenomenology in
our Galaxy. By assuming a benchmark baryonic disk density profile and two
popular families of MOND interpolating functions, we show for the first time
that the recent discovery of the declining Galactic rotation curve in the outer
region ( kpc) can almost rule out the MOND phenomenology at
more than . This strongly supports some of the previous studies
claiming that MOND is neither a fundamental theory nor a universal description
of galactic properties.Comment: Accepted in Ap
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