In this paper,we discuss the unitary transformation induced by Z_6 rotations of noncommutative space onthe states |k,q,s〉,which plays a key role in construction for noncommutative solitons T^2/Z_6 by GHS method.As ar...In this paper,we discuss the unitary transformation induced by Z_6 rotations of noncommutative space onthe states |k,q,s〉,which plays a key role in construction for noncommutative solitons T^2/Z_6 by GHS method.As aresult,we prove a well-known 'Gauss Sum' formula in the number theory through a concise way.展开更多
Temporal and three-dimensional(3 D) spatial information is important for the characterization of wireless channels. In this paper, the commonly used array signal processing(ASP) methods to estimate channel parameters ...Temporal and three-dimensional(3 D) spatial information is important for the characterization of wireless channels. In this paper, the commonly used array signal processing(ASP) methods to estimate channel parameters are summarized. Firstly, algorithms that can be used to estimate azimuth angle of arrival(AAo A) and elevation Ao A(EAo A) are introduced. They include multiple signal classification(MUSIC), estimation of signal parameter via rotational invariance techniques(ESPRIT), and Unitary ESPRIT algorithms. Secondly, algorithms that can be used to jointly estimate delay, AAo A, and EAo A are given. They include joint angle and delay estimation(JADE) MUSIC, JADE ESPRIT, shift-invariance(SI) JADE, and space-alternating generalized expectation-maximization(SAGE) algorithms. We also propose an improved SIJADE algorithm to further reduce computation complexity by incorporating with the Unitary ESPRIT algorithm. Performance of the above algorithms to extract only spatial information and to jointly extract temporal and spatial information is compared in both synthetic and 60 GHz real channel environments. Simulation results show that with the inclusion of delay estimation, the joint temporal and spatial estimation algorithms can provide better resolution than algorithms estimating only angles.Measurement data processing results show that MUSIC algorithm can provide comparable results with SAGE algorithm in estimating AAoA and EAoA. SI-JADE and the improved SI-JADE algorithms are also applicable to process 60 GHz channel measurement data.However, MUSIC, SI-JADE, and the improved SI-JADE algorithms can greatly reduce computational burden compared with SAGE algorithm. At last, some future directions are pointed out.展开更多
The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation...The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation of historical transformations of state borders of Georgia throughout of XIX-XX centuries and identification the leading geographical factors. Special emphasis has been made on geographical and cartometric analysis of modern state border of Georgia. In order to identify the historical transformations of state border that have used different methods as well as GIS-technologies, the research is based on the historical, cartographical and statistical data. On the base of a lot of cartographic sources, it is concluded that the borderline in modem topographic maps is often plotted by ignoring the international practice related to plotting the state borders across the physical-geographical objects. This is why the geographical factor seems important in the historical transformations of the state border creating similarly a negative perspective in the future. The main results of research are： （1） classification of geographical factors causing the transformations of the state borders; （2） Evaluation of sensitivity of state border; and （3） creation of DB of the state border of Georgia, allowing continuing the studies in the future.展开更多
With the aid of symbolic computation system Maple, some families of new rational variable separation solutions of the （2＋1）-dimensional dispersive long wave equations are constructed by means of a function transfor...With the aid of symbolic computation system Maple, some families of new rational variable separation solutions of the （2＋1）-dimensional dispersive long wave equations are constructed by means of a function transformation, improved mapping approach, and variable separation approach, among which there are rational solitary wave solutions, periodic wave solutions and rational wave solutions.展开更多
In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation r...In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation results show that NbAs and TaAs have similar phase diagrams, the same structural phase transition sequence I41md→Pδm2→}P21/c→Pm3m, and slightly different transition pressures. The phase transition sequence of NbP and TaP differs somewhat from that of NbAs and TaAs, in which new structures emerge, such as the Cmcm structure in NbP and the Pmmn structure in TaP. Interestingly, we found that in the electronic structure of the high-pressure phase Pδm2-NbAs, there are coexisting Weyl points and triple degenerate points, similar to those found in high-pressure Pδm2-TaAs.展开更多
We introduce Tsallis mapping in Bianconi-Barabgsi （B-B） fitness model of growing networks. This mapping addresses the dynamical behavior of the fitness model within the framework of nonextensive statistics mechanics...We introduce Tsallis mapping in Bianconi-Barabgsi （B-B） fitness model of growing networks. This mapping addresses the dynamical behavior of the fitness model within the framework of nonextensive statistics mechanics, which is characterized by a dimensionless nonextensivity parameter q. It is found that this new phenomenological parameter plays an important role in the evolution of networks： the underlying evolving networks may undergo a different phases depending on the q exponents, comparing to the original B-B fitness model, and the corresponding critical transition temperature Tc is also identified.展开更多
基金Supported by National Natural Science Foundation of China under Grant No.10575080
文摘In this paper,we discuss the unitary transformation induced by Z_6 rotations of noncommutative space onthe states |k,q,s〉,which plays a key role in construction for noncommutative solitons T^2/Z_6 by GHS method.As aresult,we prove a well-known 'Gauss Sum' formula in the number theory through a concise way.
基金support from the Natural Science Foundation of China (Grant No. 61210002, 61371110)EU H2020 ITN 5G Wireless project (No. 641985)+1 种基金EU H2020 RISE TESTBED project (No. 734325)EPSRC TOUCAN project (Grant No. EP/L020009/1)
文摘Temporal and three-dimensional(3 D) spatial information is important for the characterization of wireless channels. In this paper, the commonly used array signal processing(ASP) methods to estimate channel parameters are summarized. Firstly, algorithms that can be used to estimate azimuth angle of arrival(AAo A) and elevation Ao A(EAo A) are introduced. They include multiple signal classification(MUSIC), estimation of signal parameter via rotational invariance techniques(ESPRIT), and Unitary ESPRIT algorithms. Secondly, algorithms that can be used to jointly estimate delay, AAo A, and EAo A are given. They include joint angle and delay estimation(JADE) MUSIC, JADE ESPRIT, shift-invariance(SI) JADE, and space-alternating generalized expectation-maximization(SAGE) algorithms. We also propose an improved SIJADE algorithm to further reduce computation complexity by incorporating with the Unitary ESPRIT algorithm. Performance of the above algorithms to extract only spatial information and to jointly extract temporal and spatial information is compared in both synthetic and 60 GHz real channel environments. Simulation results show that with the inclusion of delay estimation, the joint temporal and spatial estimation algorithms can provide better resolution than algorithms estimating only angles.Measurement data processing results show that MUSIC algorithm can provide comparable results with SAGE algorithm in estimating AAoA and EAoA. SI-JADE and the improved SI-JADE algorithms are also applicable to process 60 GHz channel measurement data.However, MUSIC, SI-JADE, and the improved SI-JADE algorithms can greatly reduce computational burden compared with SAGE algorithm. At last, some future directions are pointed out.
文摘The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation of historical transformations of state borders of Georgia throughout of XIX-XX centuries and identification the leading geographical factors. Special emphasis has been made on geographical and cartometric analysis of modern state border of Georgia. In order to identify the historical transformations of state border that have used different methods as well as GIS-technologies, the research is based on the historical, cartographical and statistical data. On the base of a lot of cartographic sources, it is concluded that the borderline in modem topographic maps is often plotted by ignoring the international practice related to plotting the state borders across the physical-geographical objects. This is why the geographical factor seems important in the historical transformations of the state border creating similarly a negative perspective in the future. The main results of research are： （1） classification of geographical factors causing the transformations of the state borders; （2） Evaluation of sensitivity of state border; and （3） creation of DB of the state border of Georgia, allowing continuing the studies in the future.
基金supported by the Scientific Research Foundation of Beijing Information Science and Technology UniversityScientific Creative Platform Foundation of Beijing Municipal Commission of Education
文摘With the aid of symbolic computation system Maple, some families of new rational variable separation solutions of the （2＋1）-dimensional dispersive long wave equations are constructed by means of a function transformation, improved mapping approach, and variable separation approach, among which there are rational solitary wave solutions, periodic wave solutions and rational wave solutions.
基金supported by the National Key R&D Program of China(Grant No.2016YFA0300404)the National Key Projects for Basic Research in China(Grant No.2015CB921202)+4 种基金the National Natural Science Foundation of China(Grant Nos.11574133,and 51372112)the Natural Science Foundation Jiangsu Province(Grant No.BK20150012)the Science Challenge Project(Grant No.TZ2016001)the Fundamental Research Funds for the Central UniversitiesSpecial Program for Applied Research on Super Computation of the National Natural Science FoundationGuangdong Joint Fund
文摘In this study, we used the crystal structure search method and first-principles calculations to systematically explore the highpressure phase diagrams of the TaAs family （NbP, NbAs, TaP, and TaAs）. Our calculation results show that NbAs and TaAs have similar phase diagrams, the same structural phase transition sequence I41md→Pδm2→}P21/c→Pm3m, and slightly different transition pressures. The phase transition sequence of NbP and TaP differs somewhat from that of NbAs and TaAs, in which new structures emerge, such as the Cmcm structure in NbP and the Pmmn structure in TaP. Interestingly, we found that in the electronic structure of the high-pressure phase Pδm2-NbAs, there are coexisting Weyl points and triple degenerate points, similar to those found in high-pressure Pδm2-TaAs.
基金Supported by the National Natural Science Foundation of China under Grant No. 10875058the Initiative Plan of Shanghai Education Committee under Grant No. 10YZ76the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (SRF for ROCS,SEM)
文摘We introduce Tsallis mapping in Bianconi-Barabgsi （B-B） fitness model of growing networks. This mapping addresses the dynamical behavior of the fitness model within the framework of nonextensive statistics mechanics, which is characterized by a dimensionless nonextensivity parameter q. It is found that this new phenomenological parameter plays an important role in the evolution of networks： the underlying evolving networks may undergo a different phases depending on the q exponents, comparing to the original B-B fitness model, and the corresponding critical transition temperature Tc is also identified.
