基于多层虚拟拓扑节能的SDN数据中心网络流量调度算法

针对富连接数据中心网络在低负载时能源利用率较低的问题,提出一种节能的多层虚拟拓扑流量调度算法(EMV-SDN).建立节能流量调度问题的整形线性规划(Integral Linear Programing,ILP)优化数学模型,使得在承载所有网络负载的前提下,网络能源消耗最小.提出节能的多层虚拟拓扑流量调度算法来求解数...     

Proactive mitigation of impact of wormholes and sinkholes on routing security in energy-efficient wireless sensor networks

Sensor networks are deployed in a variety of environments for unattended operation. In a hostile terrain, sensor nodes are vulnerable to node capture and cryptographic material compromise. Compromised nodes can be used for launching wormhole and sinkhole attacks in order to prevent sensitive data from reaching intended destinations. Our objective in this paper is mitigating the impact of undetected compromised nodes on routing. To this end, we develop metrics for quantifying risk of paths in a network. We then introduce a novel routing approach: Secure-Path Routing (SPR) that uses expected path risk as a parameter in routing. Quantified path risk values are used in routing to reduce traffic flow over nodes that have high expected vulnerability. Selecting low risk routes may lead to the choice of energy-expensive routes. Thus, we develop algorithms for balancing risk with other path selection parameters, including energy consumption. We conduct simulation experiments to evaluate the effectiveness of our approach and study the tradeoff between security and energy. Simulation shows that SPR can be quite effective at increasing traffic flow over legitimate routes and that the impact of SPR on network lifetime is negligible.

一种嵌入铁电晶体管内容寻址存储器的高能效浮点运算结构

随着数据密集型应用的日益增多,内存墙问题已成为制约计算效率的瓶颈。该文提出一种新型的浮点数(FP)运算结构,该结构嵌入了基于铁电场效应晶体管(FeFET)的三元内容寻址存储器(TCAM)以实现高效的计算。通过特定规则设计的超高密度TCAM结构,可以用能效更高的TCAM搜索操作代替部分传统浮点运算,从而节约整体能耗。仿真实验证明,该文所提结构和运算执行流程,与常规浮点运算单元(FPU)相比,可以降低多达33%的能耗。     

Distributed virtual machine consolidation: A systematic mapping study

Background:Virtual Machine (VM) consolidation is an effective technique to improve resource utilization and reduce energy footprint in cloud data centers. It can be implemented in a centralized or a distributed fashion. Distributed VM consolidation approaches are currently gaining popularity because they are often more scalable than their centralized counterparts and they avoid a single point of failure.Objective:To present a comprehensive, unbiased overview of the state-of-the-art on distributed VM consolidation approaches.Method:A Systematic Mapping Study (SMS) of the existing distributed VM consolidation approaches.Results:19 papers on distributed VM consolidation categorized in a variety of ways. The results show that the existing distributed VM consolidation approaches use four types of algorithms, optimize a number of different objectives, and are often evaluated with experiments involving simulations.Conclusion:There is currently an increasing amount of interest on developing and evaluating novel distributed VM consolidation approaches. A number of research gaps exist where the focus of future research may be directed.     

基于贝叶斯网络的无线传感网高效数据传输方法

无线环境复杂经常导致高误码率的出现,该文结合无线传感网对传输能耗有较高要求的特点,针对分组协议字段错误修复问题提出基于贝叶斯网络的最大后验修复方法MAP-BN。该方法使得传感网节点在无需任何编码的情况下可以得到向前纠错的能力。MAP-BN算法利用贝叶斯网络对分组协议字段的先验信息进行建模,并在此基础上利用动态规划算法进行最大后验概率推理,成功降低了最大后验修复的计算复杂度。仿真和分析结果表明,MAP-BN算法具有良好的数据差错控制能力,并可以很大程度上提升网络节点传输数据的能效性。     

某商务办公楼能效管理系统设计方案

本文介绍了某商务办公建筑能效综合管理系统的设计理念,以及能效管理系统的系统结构、能耗考核方法、能耗数据编码上传、主要功能、后台管理界面设计等。     

Energy-efficient MAC in ad-hoc networks inspired by conflict resolution concepts

In this paper, we address the medium access control (MAC) problem in ad-hoc networks from the energy-efficiency perspective and develop a residual-energy-based collision resolution algorithm (CRA) for energy-limited terminals. In this interval-splitting-based algorithm, packets involved in a collision are partitioned into subsets according to the amount of residual battery energy left at the corresponding terminals, and retransmissions are scheduled according to a tree structure. To avoid possible performance degradations for cases of not evenly spread battery energies, we propose a hybrid approach that interchangeably uses energy-based and first-come-first-served CRA’s to resolve packet conflicts. We extend the proposed energy-based collision resolution (CR) approach to cases without hard energy constraints but, rather, with energy-efficiency objectives. The algorithm then utilizes the distance from the receiver as the criterion. We then address energy-efficient conflict resolution in general multi-hop ad-hoc networks. In this context, a useful but yet simple method is proposed to reduce the interdependence between collision resolution processes at different receivers, which would otherwise distort the general structure of tree-splitting algorithms. We evaluate the proposed algorithms via simulation for communication systems ranging from simple single-cell classical collision channel models to general multi-hop wireless ad-hoc networks.     

大型公共建筑设备管理系统的节能规划设计研究

本文针对我国建筑设备管理系统的节能现状和智能建筑设计标准的要求,从功能结构和系统集成策略的角度设计了大型公建设备管理系统节能规划总体框架。详细探讨了能耗分项计量模型构建、能耗数据处理和基于能耗分项计量的节能诊断的一般思路。提出了我国建筑设备管理系统节能规划与实施过程中存在的关键问题及对策。     

On the effectiveness of single and multiple base station sleep modes in cellular networks

In this paper we study base station sleep modes that, by reducing power consumption in periods of low traffic, improve the energy efficiency of cellular access networks. We assume that when some base stations enter sleep mode, radio coverage and service provisioning are provided by the base stations that remain active, so as to guarantee that service is available over the whole area at all times. This may be an optimistic assumption in the case of the sparse base station layouts typical of rural areas, but is, on the contrary, a realistic hypothesis for the dense layouts of urban areas, which consume most of the network energy.     

The new research centre of the Brazilian Petroleum Company in Rio de Janeiro,Brazil: The achievements in the thermal performance of air-conditioned buildings in the tropics

The study on the thermal performance of the air-conditioned buildings of the new research centre of the Brazilian Petroleum Company, in the tropical climate of Rio de Janeiro, was part of a bigger research and consultancy project involving environmental issues. The architectural design was the subject of a national competition in 2004, encompassing over 100,000 m². According to the design brief, out of the 10 buildings of the new research centre, 7 have to be either completely or partially air-conditioned, due to specific occupation requirements. The challenge for better thermal performance was related to systems’ energy efficiency, to the introduction of natural ventilation and to the notion of adaptive comfort, which were verified with the support of thermal dynamic simulations. At the early stages of the assessments, the potential for natural ventilation in the working spaces considering the mixed-mode strategy achieved 30% of occupation hours. However, the development of the design project led to fully air-conditioned working spaces, due to users’ references regarding the conventional culture of the office environment. Nevertheless, the overall architectural approach in accordance to the climatic conditions still showed a contribution to the buildings’ energy efficiency.