A software-defined networking approach for handover management with real-time video in WLANs

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.

A DUAL-CAMERA VIDEO-TRACKING SYSTEM USING PROJECTION ALGORITHM

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.

Preliminary Study on Water Demand Law of 1-0 Rooted Cuttings of Populus szechuanica

In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and the law of water demand of P.szechuanica was grasped.In this paper,potted seedlings of 1-0 rooted cuttings of P.szechuanica were taken as research objects,and change situation of water consumption under different water control gradients was measured regularly by using weighing method,further analyzing dynamic change of water consumption of P.szechuanica and revealing water demand law of 1-0 rooted cuttings of P.szechuanica.The results showed that total change of water consumption of 1-0 rooted cuttings of P.szechuanica had"slow-fast-slow-fast"double-peak trend in the growth period of the current year,and corresponded with univariate linear relation(R^(2)=0.7137),with significant difference.In whole growth period,water consumption in August was the highest,which was 2.7 times of that in June and July and 1.5 times of that after September.In different water control treatments,the dynamic changes of daily and monthly water consumption were significantly different.In seven water control treatments,monthly water consumption was between(6315.95±1690.70)and(10105.28±3065.30)g/month,and mean was(8211.07±2308.23)g/month.With intensification of water control treatment,water consumption increased,but there was no seedling death due to water shortage.P.szechuanica has great plasticity in water demand,and can survive in both arid and humid environments.Meanwhile,it is revealed that P.szechuanica is the most widely distributed tree species in the region.

显卡Video也无线 启亨大银家无线TI4200-8X显卡

随着计算机技术的不断发展、进步,鼠标、键盘等输入设备已逐渐引用了无线技术,为用户带来了很多方便之处。此次由启亨所推出的大银家无线TI4200-8X显卡则为显卡的无线传输开辟了先河。

高二册19-20单元词语辨析

demand为“要求”或“查问”，语气较重，是强硬、断然的口气，它可接名词、不定式及用虚拟语气表示的宾语从句。当宾语指人时，要加介词of；require为“请求”或“恳求”，语气较和缓，指非常礼貌地正式请求，它可接名词及不定式的复合结构，也可以后跟宾语从句。

Design and implementation of digital content metadata system

Today's multimedia services are far beyond just the voice and data services:they have been diversified tremendously after fueled by the advancement of network infrastructures as well as the sudden surge of multimedia data itself.Currently,researches on metadata insertion,management and transfer keep going very well in order to provide a variety of services to users.In this paper,we propose the design and implementation methods of digital contents metadata system for insertion,storage and retrieval of metadata.The performance evaluation shows that the proposed method performs better than the existing method.

广播电视单向网络下互动点播的实现方法研究和设计

提出了一种利用智能手机与互动点播系统交互,通过手机扫电视屏幕二维码,获取电视机顶盒所在网络位置等信息,由手机代理机顶盒向互动点播系统发请求,从而完成互动点播功能的一种方法。该方法是通过移动通信网络与数字电视广播网结合实现机顶盒互动点播的功能,弥补了必须在现有数字电视广播网络中建设双向网络才能实现互动点播功能的缺欠。它融合了手机与电视各自的优势,即在手机屏幕操控,在电视屏幕显示,从而提升了用户的体验。