变频空调器及其节能

变频空调器是一种新型机种.变频技术在空调器中的应用,使得空调在整机性能、舒适性等方面得以大大提高.     

从换路定律证明看扩充实数的必要性

指出了在电路分析课程中换路定律证明方面存在的矛盾,证明矛盾的根源在于实数的完备性,并依此说明了建立广义实数概念的必要性.     

基于视频的城市快速路交通流检测及车辆行为监控

提出一种针对城市快速路的视频监控系统,完成交通流及道路异常行为检测.流量检测模块对车辆进行实时跟踪获得各类交通流统计数据,实现快速路车辆运行状况的全面掌控.异常监控模块运用隐马尔科夫模型,对带有时间和空间信息的车辆轨迹进行训练,获得路径划分后对道路车辆轨迹进行参数匹配,提取诸如超低(高)速行驶、违章停车、违规掉头等异常...     

年幼儿童的视频学习:研究与展望

视频资源已成为当代儿童生活中不可或缺的组成部分。研究表明,尽管年幼儿童通过视频进行了学习,但在年幼儿童,尤其是3岁前儿童的认知发展过程中,视频学习的作用可能并不明显。因此,理解年幼儿童视频学习的视角应当从对认知发展的关注转换到对社会性发展的关注上来,在年幼儿童社会化的过程中理解视频学习,揭示视频学习的社会性本质。视频资源不应是单纯的知识载体,而应当成为儿童的社会伙伴。考察视频环境中年幼儿童的学习,应在儿童、他人和视频构成的互动系统中,关注人际互动与人机互动的动态协调。强调视频学习的社会性本质,可以为年幼儿童学习理论的建设带来新思路,也可以为视频资源的教育应用及相关政策的制定提供依据,为视频节目的设计与制作带来新的启示。     

基于录像分析背景下的代数课堂教学语言研究——以两堂《分式的乘除》课堂实录为例

量化分析《分式的乘除》两堂录像课,参考弗兰德提出的"Flanders互动分析系统"师生语言分类,将代数课堂教学语言进行分类,并就不同教学环节,对教学语言比较分析,得出以下结论:(1)课堂教学中,教师的教学语言所用时间占有很高的比例,各种类型的教学语言的时间比例不同,以提问性语言为主;(2)代数课堂教学中两位教师在各个教学环节中教学语言所占时间比例不同,例题讲解、练习讲解环节教师语言所占的比例最大;(3)代数课堂教学各个环节中,教师大多采用提问性为主的教学语言;(4)课堂教学中,应适当减少命令性语言和提问性语言,适当增加启发性语言、反馈性语言和激励性语言,以提高教学效果.     

Video diaries: a tool to investigate sustainability-related learning in threshold spaces

This paper takes as a case study an undergraduate field class from a UK university to rural Uganda. It describes and evaluates the use of video diaries as a tool for investigating the process of transformative learning in the context of education for sustainability. The applicability of threshold concept theory to this learning is investigated. Results show the video diary technique to be much more successful in capturing the development of student learning than written diaries. Despite some practical difficulties, rich data were generated. Analysis demonstrated that learning met three of the five criteria for threshold concepts: the learning was transformative, integrative and troublesome. Further research could test whether the learning in this case study met the threshold concept criterion of irreversibility. Further elaboration of the theoretical relationship between threshold concepts, transformative learning and education for sustainability is also needed. It is concluded that the video diary method is potentially transferable to other educational research contexts and may be particularly suitable for researching learning in threshold spaces.     

3DV quality model based depth maps for view synthesis in FTV system

Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems.When depth maps are derived using existing depth estimation methods,the depth distortions will cause undesirable artifacts in the synthesized views.To solve this problem,a 3D video quality model base depth maps (D-3DV) for virtual view synthesis and depth map coding in the FTV applications is proposed.First,the relationships between distortions in coded depth map and rendered view are derived.Then,a precisely 3DV quali...     

Extraction of novel features for emotion recognition

Hilbert-Huang transform method has been widely utilized from its inception because of the superiority in varieties of areas. The Hilbert spectrum thus obtained is able to reflect the distribution of the signal energy in a number of scales accurately. In this paper, a novel feature called ECC is proposed via feature extraction of the Hilbert energy spectrum which describes the distribution of the instantaneous energy. The experimental results conspicuously demonstrate that ECC outperforms the traditional short-term average energy. Combination of the ECC with mel frequency cepstral coefficients (MFCC) delineates the distribution of energy in the time domain and frequency domain, and the features of this group achieve a better recognition effect compared with the feature combination of the short-term average energy, pitch and MFCC. Afterwards, further improvements of ECC are developed. TECC is gained by combining ECC with the teager energy operator, and EFCC is obtained by introducing the instantaneous frequency to the energy. In the experiments, seven status of emotion are selected to be recognized and the highest recognition rate 83.57% is achieved within the classification accuracy of boredom reaching 100%. The numerical results indicate that the proposed features ECC, TECC and EFCC can improve the performance of speech emotion recognition substantially.     

Video retargeting using optimized crop-and-scale

Mobile devices are increasingly powerful in multimedia transmitting and browsing. However, the small screen and different aspect ratios of mobile devices lower visual quality while watching images or videos. Video retargeting is aim at fitting an existing video into arbitrary size and aspect ratio. Previous content-aware retargeting methods are mostly high computational cost, which limits their applications on the portable devices with low computation ability. In this paper, a new crop-and-scale approach is presented to adapt video to better suit the target display. We automatically find the optimal parameters of cropping window using the dynamic programming method, and then scale it to fit the target display. The cropping window can smoothly shift during a shot to follow the movement of important objects. The retargeting results using our approach introduce no deformation and jitter effects over the whole video. Experimental results show the success of our approach on adapting a variety of source videos to small display sizes.     

4-component 2-D CFDFD method in analysis of lossy circular waveguide with fractal rough surface

In this paper, equivalent surface impedance boundary condition (ESIBC), which takes fractal parameters (D, G) into SIBC, is implemented in the 4-component 2-D compact finite difference frequency domain (2-D CFDFD) method to an- alyze the propagation characteristics of lossy circular waveguide with fractal rough surface based on Weierstrass-Mandelbrot (W-M) function. Fractal parameters’ effects on attenuation constant are presented in the 3 mm lossy circular waveguide, and the attenuation constants of the fi...