Proposal for a cross layer scheme for real-time wireless video     

JEYARAJ Arulsaravana CHENG Liang EL ZARKI Magda 《浙江大学学报(A卷英文版)》2006,7(10):1690-1694

INTRODUCTION Increase in wireless system capacity through 3G services and innovative low bit rate video coding techniques have made it possible to have mobile multimedia services on hand-held systems. High quality real-time multimedia services are slowly be- ing deployed on hand-held systems. However large scale deployment at low cost is still to be realized due to technological challenges such as stringent power control under severely fading environments and the susceptibility of high qu…  相似文献   

Adaptive swarm-based routing in communication networks     

吕勇  赵光宙  苏凡军  历小润 《浙江大学学报(A卷英文版)》2004,5(7):867-872

Swarm intelligence inspired by the social behavior of ants boasts a number of attractive features,including adaptation,robustness and distributed,decentralized nature,which are well suited for routing in modern communication networks.This paper describes an adaptive swarm-based routing algorithm that increases convergence speed,reduces routing instabilities and oscillations by using a novel variation of reinforcement learning and a technique called momentum.Experiment on the dynamic network showed that adaptive swarm-based routing learns the optimum routing in terms of convergence speed and average packet latency.  相似文献   

Adaptive terminal sliding mode control for high-order nonlinear dynamic systems     

庄开宇  苏宏业  张克勤  褚健 《浙江大学学报(A卷英文版)》2003,4(1):58-63

An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method. Project supported by the National Outstanding Youth Science Foundation of China (NSFC:69725005) and the Zhejiang, Provincial Natural Science Key Foundation of China (ZD9905)  相似文献   

跨组织信息系统与组织间社会网络的互动关系研究   总被引：1，自引：0，他引：1  

陈文波  曾庆丰  黄荣辉 《软科学》2010,24(1):42-45,55

在对组织间社会网络与跨组织信息系统应用研究进行综述的基础上,提出了一个基于适应性结构化理论的跨组织信息系统与组织间社会网络互动的研究框架。这一框架将跨组织信息系统与社会网络作为影响跨组织信息系统应用的两种主要结构来源,将互动的过程分为对结构的征用与业务流程的相互作用,互动的结果影响跨组织信息系统的应用绩效。通过结构的维度划分和对互动过程进行解构,这一模型能够更好地解释跨组织信息系统的供应链使用。  相似文献   

Authentic science experiences as a vehicle for assessing orientation towards science and science careers relative to identity and agency: a response to “learning from the path followed by Brad”     

Pauline W. U. Chinn 《Cultural Studies of Science Education》2009,4(3):639-647

This response draws from the literature on adaptive learning, traditional ecological knowledge, and social–ecological systems to show that Brad’s choice is not a simple decision between traditional ecological knowledge and authentic science. This perspective recognizes knowledge systems as dynamic, cultural and historical activities characterized by diverse worldviews and ways of constructing and legitimizing knowledge. Brad’s decision is seen as an example of adaptive learning, identity development and personal/collective agency oriented to increasing tribal influence in resource management decisions and policies. I will conclude that science literacy for all is not served by a transcendent, universal, Western modern view of science.

Pauline W. U. ChinnEmail:

  相似文献   

Knowledge elaboration: A cognitive load perspective   总被引：3，自引：3，他引：0  

Slava Kalyuga   《Learning and Instruction》2009,19(5):402-410

The process of knowledge elaboration is considered from the perspective of cognitive load theory. This theory assumes that the available knowledge structures in long-term memory (LTM) are used to organize and guide cognitive processing in complex learning. Accordingly, the role of external instructional guidance in the process of knowledge elaboration could be described as providing a substitute for knowledge structures missing from LTM. Thus, the executive guidance in complex learning environments is shared between the person (based on his/her LTM knowledge structures) and another expert or instructional means. This article analyzes instructional implications of this assumption. Adaptive learning environments are suggested for tailoring knowledge elaboration processes to changing characteristics of individual learners. Means for identifying and predicting the learner's LTM-based executive guidance are proposed so that they can be utilized in the building of adaptive learning environments.  相似文献   

ART2网络在民航气象数据库业务系统维护中的应用     

刘丹  傅鹂 《重庆职业技术学院学报》2009,18(2):98-100

基于人工神经网络AKT2的维护经验收集子系统作为民航气象业务维护支持系统的子系统,集故障识别、方法记录等功能于一体,充分发挥了ART2网络边学习边回想、在线学习的优势,为维护经验的收集提供一个强有力的平台。  相似文献   

Parallel processing architecture of H.264 adaptive deblocking filters     

Hu Wei  Tao Lin  Zheng-hui Lin 《浙江大学学报(A卷英文版)》2009,10(8):1160-1168

In H.264, computational complexity and memory access of deblocking filters are variable, dependent on video contents. This paper proposes a VLSI architecture of deblocking filters with adaptive dynamic power, which avoids redundant computations and memory accesses by precluding the blocks that can be skipped. The vertical and horizontal edges are simultaneously processed in an advanced scan order to speed up the decoder. As a result, dynamic power of the proposed architecture can be reduced adaptively （up to about 89%） for different videos, and the off-chip memory access is improved when compared to previous designs. Moreover, the processing capability of the proposed architecture is in particular appropriate for real-time deblocking of high-definition television （HDTV, 1920× 1080 pixels/frame, 60 frames/s video signals） video operation at 62 MHz. Using the proposed architecture, power can be reduced by up to about 89% and processing time by from 25% to 81% compared with previous designs.  相似文献   

Adaptive fractional window increment of TCP in multihop ad hoc networks     

Liang-hui Ding  Wen-jun Zhang  Xin-bing Wang  Liang Qian  You-yun Xu 《浙江大学学报(A卷英文版)》2009,10(6):820-827

We propose an adaptive fractional window increasing algorithm （AFW） to improve the performance of the fractional window increment （FEW） in （Nahm et al., 2005）. AFW fully utilizes the bandwidth when the network is idle, and limits the operating window when the network is congested. We evaluate AFW and compare the total throughput of AFW with that of FeW in different scenarios over chain, grid, random topologies and with hybrid traffics. Extensive simulation through ns2 shows that AFW obtains 5% higher throughput than FeW, whose throughput is significantly higher than that of TCP-Newreno, with limited modi- fications.  相似文献   

Science Letters: Human-centered modeling for style-based adaptive games     

Chee-onn WONG  Jon-gin KIM  Eun-jung HAN  Kee-chui JUNG 《浙江大学学报(A卷英文版)》2009,10(4)

This letter proposes a categorization matrix to analyze the playing style of a computer game player for a shooting game genre. Our aim is to use human-centered modeling as a strategy for adaptive games based on entertainment measure to evaluate the playing experience. We utilized a self-organizing map (SOM) to cluster the player's style with the data obtained while playing the game. We further argued that style-based adaptation contributes to higher enjoyment, and this is reflected in our experiment using a supervised multilayered perceptron (MLP) network.  相似文献