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Search Results: 1 - 10 of 89983 matches for " Lei Chen "
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Partial Feedback Based Orthogonal Space-Time Block Coding With Flexible Feedback Bits  [PDF]
Lei Wang, Zhigang Chen
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2024
Abstract: The conventional orthogonal space-time block code (OSTBC) with limited feedback has fixed p-1 feedback bits for the specific ntp transmit antennas. A new partial feedback based OSTBC which provides flexible feedback bits is proposed in this paper. The proposed scheme inherits the properties of having a simple decoder and the full diversity of OSTBC, moreover, preserves full data rate. Simulation results show that for ntp transmit antennas, the proposed scheme has the similar performance with the conventional one by using p-1 feedback bits, whereas has the better performance with more feedback bits.
Trust Development and Transfer from Electronic Commerce to Social Commerce: An Empirical Investigation  [PDF]
Lei Chen, Ruimei Wang
American Journal of Industrial and Business Management (AJIBM) , 2016, DOI: 10.4236/ajibm.2016.65053
Abstract: The development of social networking sites (SNSs) and Web 2.0 technology have given rise to a new electronic commerce paradigm called social commerce. Social commerce is a subset of electronic commerce and uses SNSs for social interactions and user contributions to facilitate the online buying and selling of products and services. Recent years have witnessed the rapid growth of social commerce in China, but users are not willing to share their online shopping information and the intention to use social commerce is lower than traditional electronic commerce. So improving Consumers’ trust and use intention has become a crucial factor in the success of social commerce. Since social commerce users mostly are e-commerce users, this paper discusses whether trust on e-commerce can transfer to social commerce, and what are the factors influencing trust and trust performance of social commerce. The results of an empirical analysis based on a sample of 449 users with online shopping experience indicate that consumers’ trust in e-commerce has a significant positive impact on trust in social commerce and relative advantage; perceived relative advantage and result demonstrability positively affect customers’ trust in social commerce and trust in social commerce positively affects their intention to use; while perceived risk negatively affects a customer’s intention to use.
A Trust Evaluation Model for Social Commerce Based on BP Neural Network  [PDF]
Lei Chen, Ruimei Wang
Journal of Data Analysis and Information Processing (JDAIP) , 2016, DOI: 10.4236/jdaip.2016.44013
Abstract: Recent years we have witnessed the rapid growth of social commerce in China, but many users are not willing to trust and use social commerce. So improving consumers’ trust and purchase intention has become a crucial factor in the success of social commerce. Business factors, environment factors and social factors including twelve secondary indexes build up a social commerce trust evaluation model. Questionnaires are handed out to collect twelve secondary indexes scores as input of BP neural network and composite score of trust as output. Model simulation shows that both training samples and test samples have low level of average error and standard deviation, which certify that the model has good stability and it is a good method for evaluating social commerce trust.
A Study on the Status Quo of Chinese College Students’ Intercultural Communication Competence  [PDF]
Lei Chen, Zhihui Wang
Chinese Studies (ChnStd) , 2018, DOI: 10.4236/chnstd.2018.72014
Abstract: Intercultural encounters have become a fact of daily life in so many cities as well as towns in China, yet English learning is far from enough for cultivating talents with international vision and research on ICC has stepped on agenda. This paper is aimed at investigating the ICC stat quo of Chinese college students. The questionnaire is designed based on Byram’s YOGA including four aspects—intercultural knowledge, intercultural skills, intercultural attitude, and critical intercultural awareness. Research is done with data from the teacher-questionnaire for finding one focus of the four aspects for further research of influencing factors of ICC and with data from the student-questionnaire, on the presumed potential related factors of ICC like major, gender, cultural curriculums, and experience abroad for finding out Chinese college students’ ICC stat quo. 10 (half science and half literary arts) are interviewed to find out how the results come into being. Through the analysis of teacher-questionnaire data, the author gets that intercultural attitude is of the most importance to ICC. The results come out possibly because the acquiring of intercultural awareness, intercultural skills and intercultural knowledge are decided by intercultural attitude.
Method Research of Earthquake Prediction and Volcano Prediction in Italy  [PDF]
Lijun Chen, Xiaofeng Chen, Lei Shao
International Journal of Geosciences (IJG) , 2015, DOI: 10.4236/ijg.2015.69076
Abstract: This paper adopts the earthquake catalogue of the European Mediterranean Seismological Centre (EMSC), in accordance with the principles of Seismo-Geothermics Theory and the concept of seismic cone; it discusses the integrity of the earthquake catalogue and the overview of Mediterranean seismic cones; it focuses on the structural details and structural feature of the Italian branch of the Mediterranean seismic cone; it deduces the precursory process of subcrustal earthquake activities before two earthquakes magnitude over 6 and the eruptions of Etna volcano since 2005; then it summarizes the prediction working method of Seismo-Geothermics on estimating the general shell strength, the general period, and the rough location of future earthquake or volcano activities; and finally it discusses and explains some possible problems. The principle and working process of this method were testified in card No. 0419 in 2012, the author’s prediction card, which can apply to predict for intracrustal strong earthquakes and volcano activities within the global twenty four seismic cones. The purpose of this paper is to develop the tools and methods of the prediction of future earthquake and volcano.
Energy-Efficient Optimization for Physical Layer Security in Multi-Antenna Downlink Networks with QoS Guarantee
Xiaoming Chen,Lei Lei
Mathematics , 2013,
Abstract: In this letter, we consider a multi-antenna downlink network where a secure user (SU) coexists with a passive eavesdropper. There are two design requirements for such a network. First, the information should be transferred in a secret and efficient manner. Second, the quality of service (QoS), i.e. delay sensitivity, should be take into consideration to satisfy the demands of real-time wireless services. In order to fulfill the two requirements, we combine the physical layer security technique based on switched beam beamforming with an energy-efficient power allocation. The problem is formulated as the maximization of the secrecy energy efficiency subject to delay and power constraints. By solving the optimization problem, we derive an energy-efficient power allocation scheme. Numerical results validate the effectiveness of the proposed scheme.
Flavonoids of puerarin versus tanshinone ⅡA for ischemic stroke: a randomized controlled trial
Lei Chen
Zhong Xi Yi Jie He Xue Bao , 2011,
Abstract: Background: Flavonoids are widely used today in the treatment of ischemic stroke. The therapeutic effects and functions of flavonoids are, therefore, generating more and more interest.Objective: To investigate the therapeutic effects and functions of flavonoids of puerarin in treating patients with ischemic stroke.Design, setting, participants and interventions: A total of 67 inpatients suffering from ischemic stroke from the Department of Neurology, Changhai Hospital in China were divided into two groups randomly, the treatment group, which was treated with flavonoids of puerarin, and the control group, administered with tanshinone ⅡA sulfate instead. Main outcome measures: Defects in neurological function were evaluated according to the National Institutes of Health Stroke Scale (NIHSS) on the first day of onset. Lactate dehydrogenase (LDH), serum interleukin-6 (IL-6) and brain-derived neurotrophic factor (BDNF) levels were determined by radioimmunoassay on the second trial day. After a 14-day treatment, LDH, serum IL-6 and BDNF levels and NIHSS score were also detected, and CT perfusion imaging was used to measure and analyze the regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time (MTT).Results: On the first day, NIHSS scores of the two groups were similar. On the second day there was no significant difference in LDH and IL-6 levels between the treatment group and the control group. After a 14-day treatment, LDH and IL-6 levels and the NIHSS score in the treatment group were lower than those in the control group (P<0.05). There was no significant difference in BDNF levels in the two groups. After 14 d, the CT perfusion imaging demonstrated that the treatment group showed more effective blood perfusion than the control group. Conclusion: Flavonoids of puerarin can restrain the increase of IL-6 after acute ischemic stroke, and depress the LDH raised by reperfusion after cerebral ischemia. It can also enhance blood perfusion of the ischemic region.
Pragmatic Analysis of Fuzziness in Advertising English
Lei Chen
Asian Culture and History , 2011, DOI: 10.5539/ach.v3n2p29
Abstract: The article tentatively explores the fuzzy expressions in advertising English to realize the ultimate goal of advertising from the perspective of pragmatics. This study is devoted to the pragmatic theories employed by the advertisers in order to make advertisements persuasive, impressive to the target audience. Equipped with the pragmatic knowledge, the target audience can understand advertising language clearly.
On the Semantic Realization of Fuzziness in Advertising English
Lei Chen
Asian Social Science , 2010, DOI: 10.5539/ass.v6n8p126
Abstract: The choice of fuzziness to establish images of products or services is quite common in advertising English. Advertisers often employ fuzzy expressions to grab consumers’ attention, realize persuasion function, and avoid lawful and ethical responsibilities. The author aims at drawing attention to the application of fuzziness in advertising and equipping consumers with better understanding of it to avoid mistakes in interpreting and help advertisers produce more successful advertisements.
Hybrid Neural Network Architecture for On-Line Learning  [PDF]
Yuhua Chen, Subhash Kak, Lei Wang
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.23030
Abstract: Approaches to machine intelligence based on brain models use neural networks for generalization but they do so as signal processing black boxes. In reality, the brain consists of many modules that operate in parallel at different levels. In this paper we propose a more realistic biologically inspired hybrid neural network architecture that uses two kinds of neural networks simultaneously to consider short-term and long-term characteristics of the signal. The first of these networks quickly adapts to new modes of operation whereas the second one provides more accurate learning within a specific mode. We call these networks the surfacing and deep learning agents and show that this hybrid architecture performs complementary functions that improve the overall learning. The performance of the hybrid architecture has been compared with that of back-propagation perceptrons and the CC and FC networks for chaotic time-series prediction, the CATS benchmark test, and smooth function approximation. It is shown that the proposed architecture provides a superior performance based on the RMS error criterion.
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