Flipped classroom is a brand-new teaching mode both at home and abroad. Its core is to reverse teaching sequence and teaching content by letting students watch self-made videos to learn relatively junior teaching cont...Flipped classroom is a brand-new teaching mode both at home and abroad. Its core is to reverse teaching sequence and teaching content by letting students watch self-made videos to learn relatively junior teaching content before class, thus leaving students adequate space to exert full activities in the classroom to complete knowledge absorption and consolidation. This article focus mainly on the design principles and relevant experiences of video production. In the meanwhile, the article also puts forward instructive suggestions for teachers to make appealing and stylistic videos as well as mobilize the enthusiasm of students.Video as the stepping stone only serves as a media to convey knowledge before class, the class is the core to convert students' traditional role to be the real master by a series of effective activities, which should be carefully designed by teachers. So the second focus of the articles falls on the design principles of in-class activities.展开更多
To achieve high performance and reliability in video streaming over wireless local area networks （WLANs）, one must jointly consider both optimized association to access points （APs） and handover management based o...To achieve high performance and reliability in video streaming over wireless local area networks （WLANs）, one must jointly consider both optimized association to access points （APs） and handover management based on dynamic scanning of alternate APs. In this article, we propose a new architecture within the software-defined networking （SDN） framework, which allows stations to be connected to several APs simultaneously and to switch fast between them. We evaluate our system in a real-time testbed and demonstrate that our SDN-based handover mechanism significantly reduces the number and duration of video freeze events and allows for smaller playout buffers.展开更多
This paper makes micro video combine with flipped classroom,constructs the teaching mode of flipped classroom based on micro video.This mode specifically include three teaching processes,such as design and practice of...This paper makes micro video combine with flipped classroom,constructs the teaching mode of flipped classroom based on micro video.This mode specifically include three teaching processes,such as design and practice of pre class task,design and practice of classroom interaction task,task and practice of comprehensive evaluation after class,and tries in the teaching of the course of Financial Management,improves the students＇ autonomous learning ability, enhances the participation degree of classroom teaching,promotes knowledge absorption of students,the effect of teaching is good.展开更多
This paper presents a video-tracking system composed of two cameras. One camera acts for producing an in-focus image of the object and the other one ensures an extended vision field under monitoring. Such a system sch...This paper presents a video-tracking system composed of two cameras. One camera acts for producing an in-focus image of the object and the other one ensures an extended vision field under monitoring. Such a system scheme can achieve an excellent tracking performance,especially under various unfavorable conditions. A projection algorithm is used for the calculation of the displacement of the moving object. As a result, the computational cost is reduced greatly.In order that the tracking action of the system persists even if the object is sheltered or ns acceleration is larger than a specified threshold, a dedicated tracking algorithm on the basis of the α-β filtering is designed. Experiments show that the algorithm is efficient and the system works very well.展开更多
Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and effic...Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.展开更多
文摘Flipped classroom is a brand-new teaching mode both at home and abroad. Its core is to reverse teaching sequence and teaching content by letting students watch self-made videos to learn relatively junior teaching content before class, thus leaving students adequate space to exert full activities in the classroom to complete knowledge absorption and consolidation. This article focus mainly on the design principles and relevant experiences of video production. In the meanwhile, the article also puts forward instructive suggestions for teachers to make appealing and stylistic videos as well as mobilize the enthusiasm of students.Video as the stepping stone only serves as a media to convey knowledge before class, the class is the core to convert students' traditional role to be the real master by a series of effective activities, which should be carefully designed by teachers. So the second focus of the articles falls on the design principles of in-class activities.
文摘To achieve high performance and reliability in video streaming over wireless local area networks （WLANs）, one must jointly consider both optimized association to access points （APs） and handover management based on dynamic scanning of alternate APs. In this article, we propose a new architecture within the software-defined networking （SDN） framework, which allows stations to be connected to several APs simultaneously and to switch fast between them. We evaluate our system in a real-time testbed and demonstrate that our SDN-based handover mechanism significantly reduces the number and duration of video freeze events and allows for smaller playout buffers.
文摘This paper makes micro video combine with flipped classroom,constructs the teaching mode of flipped classroom based on micro video.This mode specifically include three teaching processes,such as design and practice of pre class task,design and practice of classroom interaction task,task and practice of comprehensive evaluation after class,and tries in the teaching of the course of Financial Management,improves the students＇ autonomous learning ability, enhances the participation degree of classroom teaching,promotes knowledge absorption of students,the effect of teaching is good.
文摘This paper presents a video-tracking system composed of two cameras. One camera acts for producing an in-focus image of the object and the other one ensures an extended vision field under monitoring. Such a system scheme can achieve an excellent tracking performance,especially under various unfavorable conditions. A projection algorithm is used for the calculation of the displacement of the moving object. As a result, the computational cost is reduced greatly.In order that the tracking action of the system persists even if the object is sheltered or ns acceleration is larger than a specified threshold, a dedicated tracking algorithm on the basis of the α-β filtering is designed. Experiments show that the algorithm is efficient and the system works very well.
基金Supported by National Natural Science Foundation of China(Grant Nos.51305322,51405364,51475348)
文摘Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.
