TDD(Time Division Duplex) is one of the two duplex modes.TD-SCDMA(Time division Synchronous CDMA) is the first TDD-based cellular mobile system which is commercialized in wide area and large scale and TD-SCDMA is also...TDD(Time Division Duplex) is one of the two duplex modes.TD-SCDMA(Time division Synchronous CDMA) is the first TDD-based cellular mobile system which is commercialized in wide area and large scale and TD-SCDMA is also the first cellular mobile system which adopted smart antenna technology,also called as beamforming.As the long term evolution of TD-SCDMA,TDLTE(A)(Time Division-Lone Term Evolution,and TD-LTE Advanced) introduced OFDM(Orthogonal Frequency Division Multiplexing)and enhanced smart antenna technology together with MIMO(Multiple Input Multiple Output),which are adopted by LTE FDD(Frequency Division Duplex) either.It is indicated that TD-SCDMA and TD-LTE(A)have opened a sustainable utilization era of TDD and smart antenna Technologies in the wireless mobile communication.This paper aims to present a systematic introduction to TDD-based mobile communications from TD-SCDMA to TD-LTE and beyond and its comparisons to FDD,with particular focuses on TDD key technologies,principles of TDD cellular mobile systems,TDD evolution path,and future TDD 5G directions.We hope that this paper will provide a comprehensive overview of TDD technology upgrade and its standard evolution,and serve as a valuable reference for research on 5G mobile communication systems.It is believed that TDD will play more important role in 5G.展开更多
Learning English with specific purpose （ESP） initiatives domain knowledge and language ability with English learning to meet future job demands （Leroux ＆ Lafleur, 1995; Khan ＆ Khan, 2015）. In the information age...Learning English with specific purpose （ESP） initiatives domain knowledge and language ability with English learning to meet future job demands （Leroux ＆ Lafleur, 1995; Khan ＆ Khan, 2015）. In the information age, the innovative technologies of mobile devices make the dramatical changes in ways of teaching and learning （Atkinson, 2011; Bierstaker, Janvrin ＆ Lowe, 2014, Pittaway, 2012; Yang ＆ Che, 2015）. The focus of this study aims to examine ESP college students＇ English learning performance by using Context Aware Mobile Situated Learning （CAMSL） in Tourism and Hospitality Management field and other majors. The mixed research method is conducted for data collection and analysis. The quantitative data are collected by examining students＇ learning performance; the qualitative data are allowed to understand the students＇ perspective toward their role in using the CAMSL with Tourism related content. Eight-three students are randomly selected and divided into two groups： 42 students are assigned in the experimental group A （CAMSL）, and 41 students are assigned in control group. Two groups of students receive pretest and posttest to examine their English performance. Besides, twenty students from group A and B are selected for online survey. The survey is mailed directly to students＇ email account. Results represented by using CAMSL show the significant improvement on students＇ learning performance. In addition, the survey data indicate the benefits of using the CAMSL help students enhance their academic discourse, develop their learned knowledge to represent their profession, use English properly to speak themselves up, and provide the effectiveness of obtain domain knowledge in future workplace.展开更多
With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal tra...With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal trajectories. We present an interpoiation based Modified Hausdorff Distance algorithm for 3-dimensional spatial-temporal Trajectory Matching （IMHD-ST）. It adopts interpolation algorithm to shield the impact to the distance between trajectories due to different position updating porices, sampling granularity, initial position and so on in Moving Object Database （MOD）. Besides, it uses MHD to deal with the implicit spatial information and structural information of weighted position updating points in various trajectories and reflects the discrepancy of moving results through the spatial distance between trajectories. In addition, it adopts temporal distance corresponding to the spatial distance between trajectories to reflect the differences including direction, speed and so on during moving process. The experimental results show that the algorithrn can reflect the trajectory similarity between 3-dimensional mobile objects more correctly, accurately and robustly.展开更多
基金supported in part by the National Natural Science Foundation of China for Distinguished Young Scholar,Grant Number:61425012
文摘TDD(Time Division Duplex) is one of the two duplex modes.TD-SCDMA(Time division Synchronous CDMA) is the first TDD-based cellular mobile system which is commercialized in wide area and large scale and TD-SCDMA is also the first cellular mobile system which adopted smart antenna technology,also called as beamforming.As the long term evolution of TD-SCDMA,TDLTE(A)(Time Division-Lone Term Evolution,and TD-LTE Advanced) introduced OFDM(Orthogonal Frequency Division Multiplexing)and enhanced smart antenna technology together with MIMO(Multiple Input Multiple Output),which are adopted by LTE FDD(Frequency Division Duplex) either.It is indicated that TD-SCDMA and TD-LTE(A)have opened a sustainable utilization era of TDD and smart antenna Technologies in the wireless mobile communication.This paper aims to present a systematic introduction to TDD-based mobile communications from TD-SCDMA to TD-LTE and beyond and its comparisons to FDD,with particular focuses on TDD key technologies,principles of TDD cellular mobile systems,TDD evolution path,and future TDD 5G directions.We hope that this paper will provide a comprehensive overview of TDD technology upgrade and its standard evolution,and serve as a valuable reference for research on 5G mobile communication systems.It is believed that TDD will play more important role in 5G.
文摘Learning English with specific purpose （ESP） initiatives domain knowledge and language ability with English learning to meet future job demands （Leroux ＆ Lafleur, 1995; Khan ＆ Khan, 2015）. In the information age, the innovative technologies of mobile devices make the dramatical changes in ways of teaching and learning （Atkinson, 2011; Bierstaker, Janvrin ＆ Lowe, 2014, Pittaway, 2012; Yang ＆ Che, 2015）. The focus of this study aims to examine ESP college students＇ English learning performance by using Context Aware Mobile Situated Learning （CAMSL） in Tourism and Hospitality Management field and other majors. The mixed research method is conducted for data collection and analysis. The quantitative data are collected by examining students＇ learning performance; the qualitative data are allowed to understand the students＇ perspective toward their role in using the CAMSL with Tourism related content. Eight-three students are randomly selected and divided into two groups： 42 students are assigned in the experimental group A （CAMSL）, and 41 students are assigned in control group. Two groups of students receive pretest and posttest to examine their English performance. Besides, twenty students from group A and B are selected for online survey. The survey is mailed directly to students＇ email account. Results represented by using CAMSL show the significant improvement on students＇ learning performance. In addition, the survey data indicate the benefits of using the CAMSL help students enhance their academic discourse, develop their learned knowledge to represent their profession, use English properly to speak themselves up, and provide the effectiveness of obtain domain knowledge in future workplace.
文摘With the development of mobile technology, Internet and GIS, LBS plays an important role in various applications. From the perspective of LBS, it is one of the main tasks of matching 3-dimensional spatial-temporal trajectories. We present an interpoiation based Modified Hausdorff Distance algorithm for 3-dimensional spatial-temporal Trajectory Matching （IMHD-ST）. It adopts interpolation algorithm to shield the impact to the distance between trajectories due to different position updating porices, sampling granularity, initial position and so on in Moving Object Database （MOD）. Besides, it uses MHD to deal with the implicit spatial information and structural information of weighted position updating points in various trajectories and reflects the discrepancy of moving results through the spatial distance between trajectories. In addition, it adopts temporal distance corresponding to the spatial distance between trajectories to reflect the differences including direction, speed and so on during moving process. The experimental results show that the algorithrn can reflect the trajectory similarity between 3-dimensional mobile objects more correctly, accurately and robustly.
