This paper is concerned with (3,n) and (4,n) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory.Given the column weight,we determine the shift values of the circulant...This paper is concerned with (3,n) and (4,n) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory.Given the column weight,we determine the shift values of the circulant permutation matrices via arithmetic analysis.The proposed constructions of quasi-cyclic LDPC codes achieve the following main advantages simultaneously:1) our methods are constructive in the sense that we avoid any searching process;2) our methods ensure no four or six cycles in the bipartite graphs corresponding to the LDPC codes;3) our methods are direct constructions of quasi-cyclic LDPC codes which do not use any other quasi-cyclic LDPC codes of small length like component codes or any other algorithms/cyclic codes like building block;4)the computations of the parameters involved are based on elementary number theory,thus very simple and fast.Simulation results show that the constructed regular codes of high rates perform almost 1.25 dB above Shannon limit and have no error floor down to the bit-error rate of 10-6.展开更多
In this paper,a two-way relay system which achieves bi-directional communication via a multiple-antenna relay in two time slots is studied.In the multiple access(MA) phase,the novel receive schemes based on Dempster-S...In this paper,a two-way relay system which achieves bi-directional communication via a multiple-antenna relay in two time slots is studied.In the multiple access(MA) phase,the novel receive schemes based on Dempster-Shafer(D-S) evidence theory are proposed at the relay node.Instead of traditional linear detection,the first proposed MIMO-DS NC scheme adopts D-S evidence theory to detect the signals of each source node before mapping them into network-coded signal.Moreover,different from traditional physical-layer network coding(PNC) based on virtual MIMO model,the further proposed MIMO-DS PNC comes from the vector space perspective and combines PNC mapping with D-S theory to obtain network-coded signal without estimating each source node signal.D-S theory can appropriately characterize uncertainty and make full use of multiple evidence source information by Dempster's combination rule to obtain reliable decisions.In the broadcast(BC) phase,the space-time coding(STC) and antenna selection(AS) schemes are adopted to achieve transmit diversity.Simulation results reveal that the STC and AS schemes both achieve full transmit diversity in the BC phase and the proposed MIMO-DS NC/PNC schemes obtain better end-to-end BER performance and throughputs compared with traditional schemes with a little complexity increasing and no matter which scheme is adopted in the BC phase,MIMO-DS PNC always achieves full end-to-end diversity gain as MIMO-ML NC but with a lower complexity and its throughput approaches the throughput of MIMO-ML NC in high SNR regime.展开更多
The present study examines the phenomenon of code-switching in college EFL learners with special reference to the theory of adaptation.Through the audio-taped observation,it identifies four major categories of code-sw...The present study examines the phenomenon of code-switching in college EFL learners with special reference to the theory of adaptation.Through the audio-taped observation,it identifies four major categories of code-switching and discusses the salient levels of certain cases.展开更多
Nowadays,computer-mediated communication(CMC) becomes one of the most convenient ways for people to connect with each other in which Chinese/English code-switching has been frequently used and widely spread.The articl...Nowadays,computer-mediated communication(CMC) becomes one of the most convenient ways for people to connect with each other in which Chinese/English code-switching has been frequently used and widely spread.The article will memeticly interpret this language phenomenon based on the authentic examples collected from various kinds of CMC,and point out that the Chinese/English code-switching in CMC is a kind of strong memeplex which includes many different strong memes,resulting in the popularity of Chinese/English code-switching in CMC.展开更多
The security of information transmission and processing due to unknown vulnerabilities and backdoors in cyberspace is becoming increasingly problematic.However,there is a lack of effective theory to mathematically dem...The security of information transmission and processing due to unknown vulnerabilities and backdoors in cyberspace is becoming increasingly problematic.However,there is a lack of effective theory to mathematically demonstrate the security of information transmission and processing under nonrandom noise(or vulnerability backdoor attack)conditions in cyberspace.This paper first proposes a security model for cyberspace information transmission and processing channels based on error correction coding theory.First,we analyze the fault tolerance and non-randomness problem of Dynamic Heterogeneous Redundancy(DHR)structured information transmission and processing channel under the condition of non-random noise or attacks.Secondly,we use a mathematical statistical method to demonstrate that for non-random noise(or attacks)on discrete memory channels,there exists a DHR-structured channel and coding scheme that enables the average system error probability to be arbitrarily small.Finally,to construct suitable coding and heterogeneous channels,we take Turbo code as an example and simulate the effects of different heterogeneity,redundancy,output vector length,verdict algorithm and dynamism on the system,which is an important guidance for theory and engineering practice.展开更多
Code-switching between English and Chinese usually occurs in students' talk when they are involved in taking communicative language activities in college English class. This paper studies the situations in which s...Code-switching between English and Chinese usually occurs in students' talk when they are involved in taking communicative language activities in college English class. This paper studies the situations in which students are likely to use codeswitching and analyzes it from the perspective of the mental world in Verscheren's Adaptation Theory. It shows that inadequate mastery of English language, cultural differences and the improper adjustment to context may lead to students' using of codeswitching. It also shows that the use of code-switching in students' talk adapts to students' cognitive elements and emotive elements as well.展开更多
My Fair Lady is a movie about how a lower class flower girl turns to an upper class lady by simply changing her language at the help of a linguist.It demonstrates the importance of communication accommodation,especial...My Fair Lady is a movie about how a lower class flower girl turns to an upper class lady by simply changing her language at the help of a linguist.It demonstrates the importance of communication accommodation,especially convergent accommodation,in using language as code and behavior to construct identity in the target community.展开更多
In the past 30 years, code-switching has been a focus in the field of linguistics in western countries. Researchers stud?ied it from different angles and have made a lot of findings.However, the researchers in China b...In the past 30 years, code-switching has been a focus in the field of linguistics in western countries. Researchers stud?ied it from different angles and have made a lot of findings.However, the researchers in China begin their studies on this issue un?til the last decade. Thus,the relevent empirical studies were less and most of them only use students from the classrooms in the sec?ondary schools or the undergraduates in the universities as the subjects.They paid little attention to the EFL classrooms in the vo?cational colleges. Vocational college students are poor in English foundation. English teachers can not finish their teaching mission in English classroom, so the use of code-switching becomes a very common phenomenon in EFL class of vocational college. In order to make teaching and learning promote and enhance each other, according to previous research findings, this paper do a fur?ther study about the teachers' use of code switching in the vocational college English intensive reading classes in China.展开更多
A global variance reduction(GVR)method based on the SPN method is proposed.First,the global multi-group cross-sections are obtained by Monte Carlo(MC)global homogenization.Then,the SP3 equation is solved to obtain the...A global variance reduction(GVR)method based on the SPN method is proposed.First,the global multi-group cross-sections are obtained by Monte Carlo(MC)global homogenization.Then,the SP3 equation is solved to obtain the global flux distribution.Finally,the global weight windows are approximated by the global flux distribution,and the GVR simulation is performed.This GVR method is implemented as an automatic process in the RMC code.The SP3-coupled GVR method was tested on a modified version of C5 G7 benchmark with a thickened water shield.The results show that the SP3-coupled GVR method can improve the efficiency of MC criticality calculation.展开更多
In this paper,the author applies Jef Verschueren's Pragmatics as a Theory of Linguistic Adaptation as the theoretical basement.And the generation of code- switching is discussed under the guidance of Yu Guodong...In this paper,the author applies Jef Verschueren's Pragmatics as a Theory of Linguistic Adaptation as the theoretical basement.And the generation of code- switching is discussed under the guidance of Yu Guodong's Adaptation Model as well.Conclusions can be drawn as: teacher's English/Chinese codeswitching is an adaptation to linguistic reality,social conventions and teacher's psychological intentions,the first two being considered as passive switching and the last being active switching.Teacher's codeswitching as understanding-facilitating strategy forms the most important factor that triggers teacher's English/Chinese codeswitching.展开更多
基金supported by the National Natural Science Foundation of China under Grants No.61172085,No.61103221,No.61133014,No.11061130539 and No.61021004
文摘This paper is concerned with (3,n) and (4,n) regular quasi-cyclic Low Density Parity Check (LDPC) code constructions from elementary number theory.Given the column weight,we determine the shift values of the circulant permutation matrices via arithmetic analysis.The proposed constructions of quasi-cyclic LDPC codes achieve the following main advantages simultaneously:1) our methods are constructive in the sense that we avoid any searching process;2) our methods ensure no four or six cycles in the bipartite graphs corresponding to the LDPC codes;3) our methods are direct constructions of quasi-cyclic LDPC codes which do not use any other quasi-cyclic LDPC codes of small length like component codes or any other algorithms/cyclic codes like building block;4)the computations of the parameters involved are based on elementary number theory,thus very simple and fast.Simulation results show that the constructed regular codes of high rates perform almost 1.25 dB above Shannon limit and have no error floor down to the bit-error rate of 10-6.
基金jointly supported by the National Natural Science Foundation of China under Grant 61201198 and 61372089the Beijing Natural Science Foundation under Grant 4132015,4132007and 4132019
文摘In this paper,a two-way relay system which achieves bi-directional communication via a multiple-antenna relay in two time slots is studied.In the multiple access(MA) phase,the novel receive schemes based on Dempster-Shafer(D-S) evidence theory are proposed at the relay node.Instead of traditional linear detection,the first proposed MIMO-DS NC scheme adopts D-S evidence theory to detect the signals of each source node before mapping them into network-coded signal.Moreover,different from traditional physical-layer network coding(PNC) based on virtual MIMO model,the further proposed MIMO-DS PNC comes from the vector space perspective and combines PNC mapping with D-S theory to obtain network-coded signal without estimating each source node signal.D-S theory can appropriately characterize uncertainty and make full use of multiple evidence source information by Dempster's combination rule to obtain reliable decisions.In the broadcast(BC) phase,the space-time coding(STC) and antenna selection(AS) schemes are adopted to achieve transmit diversity.Simulation results reveal that the STC and AS schemes both achieve full transmit diversity in the BC phase and the proposed MIMO-DS NC/PNC schemes obtain better end-to-end BER performance and throughputs compared with traditional schemes with a little complexity increasing and no matter which scheme is adopted in the BC phase,MIMO-DS PNC always achieves full end-to-end diversity gain as MIMO-ML NC but with a lower complexity and its throughput approaches the throughput of MIMO-ML NC in high SNR regime.
文摘The present study examines the phenomenon of code-switching in college EFL learners with special reference to the theory of adaptation.Through the audio-taped observation,it identifies four major categories of code-switching and discusses the salient levels of certain cases.
文摘Nowadays,computer-mediated communication(CMC) becomes one of the most convenient ways for people to connect with each other in which Chinese/English code-switching has been frequently used and widely spread.The article will memeticly interpret this language phenomenon based on the authentic examples collected from various kinds of CMC,and point out that the Chinese/English code-switching in CMC is a kind of strong memeplex which includes many different strong memes,resulting in the popularity of Chinese/English code-switching in CMC.
基金supported by National Key R&D Program of China for Young Scientists:Cyberspace Endogenous Security Mechanisms and Evaluation Methods(No.2022YFB3102800).
文摘The security of information transmission and processing due to unknown vulnerabilities and backdoors in cyberspace is becoming increasingly problematic.However,there is a lack of effective theory to mathematically demonstrate the security of information transmission and processing under nonrandom noise(or vulnerability backdoor attack)conditions in cyberspace.This paper first proposes a security model for cyberspace information transmission and processing channels based on error correction coding theory.First,we analyze the fault tolerance and non-randomness problem of Dynamic Heterogeneous Redundancy(DHR)structured information transmission and processing channel under the condition of non-random noise or attacks.Secondly,we use a mathematical statistical method to demonstrate that for non-random noise(or attacks)on discrete memory channels,there exists a DHR-structured channel and coding scheme that enables the average system error probability to be arbitrarily small.Finally,to construct suitable coding and heterogeneous channels,we take Turbo code as an example and simulate the effects of different heterogeneity,redundancy,output vector length,verdict algorithm and dynamism on the system,which is an important guidance for theory and engineering practice.
文摘Code-switching between English and Chinese usually occurs in students' talk when they are involved in taking communicative language activities in college English class. This paper studies the situations in which students are likely to use codeswitching and analyzes it from the perspective of the mental world in Verscheren's Adaptation Theory. It shows that inadequate mastery of English language, cultural differences and the improper adjustment to context may lead to students' using of codeswitching. It also shows that the use of code-switching in students' talk adapts to students' cognitive elements and emotive elements as well.
文摘My Fair Lady is a movie about how a lower class flower girl turns to an upper class lady by simply changing her language at the help of a linguist.It demonstrates the importance of communication accommodation,especially convergent accommodation,in using language as code and behavior to construct identity in the target community.
文摘In the past 30 years, code-switching has been a focus in the field of linguistics in western countries. Researchers stud?ied it from different angles and have made a lot of findings.However, the researchers in China begin their studies on this issue un?til the last decade. Thus,the relevent empirical studies were less and most of them only use students from the classrooms in the sec?ondary schools or the undergraduates in the universities as the subjects.They paid little attention to the EFL classrooms in the vo?cational colleges. Vocational college students are poor in English foundation. English teachers can not finish their teaching mission in English classroom, so the use of code-switching becomes a very common phenomenon in EFL class of vocational college. In order to make teaching and learning promote and enhance each other, according to previous research findings, this paper do a fur?ther study about the teachers' use of code switching in the vocational college English intensive reading classes in China.
基金Supported by the Shanghai Sailing Program,China(No.21YF1421100)the Startup Fund for Youngman Research at SJTU。
文摘A global variance reduction(GVR)method based on the SPN method is proposed.First,the global multi-group cross-sections are obtained by Monte Carlo(MC)global homogenization.Then,the SP3 equation is solved to obtain the global flux distribution.Finally,the global weight windows are approximated by the global flux distribution,and the GVR simulation is performed.This GVR method is implemented as an automatic process in the RMC code.The SP3-coupled GVR method was tested on a modified version of C5 G7 benchmark with a thickened water shield.The results show that the SP3-coupled GVR method can improve the efficiency of MC criticality calculation.
文摘In this paper,the author applies Jef Verschueren's Pragmatics as a Theory of Linguistic Adaptation as the theoretical basement.And the generation of code- switching is discussed under the guidance of Yu Guodong's Adaptation Model as well.Conclusions can be drawn as: teacher's English/Chinese codeswitching is an adaptation to linguistic reality,social conventions and teacher's psychological intentions,the first two being considered as passive switching and the last being active switching.Teacher's codeswitching as understanding-facilitating strategy forms the most important factor that triggers teacher's English/Chinese codeswitching.
