基于改进的集成经验模态分解的海杂波去噪

针对海杂波信号因混有噪声而难以提取的特点,提出基于改进的集成经验模态分解(MEEMD)的海杂波去噪方法。文中提出的MEEMD 在补充的集成经验模态分解(CEEMD)的基础上,利用排列熵和Savitzky-Golay 滤波对CEEMD 分解后的固有模态函数进行处理,最后在经验模态分解分解重构后得到削噪后的信号。以IPIX 雷达实测得到的海杂波数据进行仿真实验,结合最小二乘支持向量机建立混沌序列的单步预测模型,从预测误差中检测淹没在海杂波背景中的微弱信号,并用均方根误差判断去噪效果。仿真结果表明,文中所提出的MEEMD 算法对模式混淆有很好的抑制效果,去噪后得到的均方根误差为0. 000 847,比去噪前的均方根误差0. 012 2 降低了两个数量级。     

A Nonlinear Coordinated Approach to Enhance the Transient Stability of Wind Energy-Based Power Systems

This paper proposes a novel framework that enables the simultaneous coordination of the controllers of doubly fed induction generators (DFIGs) and synchronous generators (SGs). The proposed coordination approach is based on the zero dynamics method aims at enhancing the transient stability of multi-machine power systems under a wide range of operating conditions. The proposed approach was implemented to the IEEE 39-bus power systems. Transient stability margin measured in terms of critical clearing time along with eigenvalue analysis and time domain simulations were considered in the performance assessment. The obtained results were also compared to those achieved using a conventional power system stabilizer/power oscillation (PSS/POD) technique and the interconnection and damping assignment passivity-based controller (IDA-PBC). The performance analysis confirmed the ability of the proposed approach to enhance damping and improve system’s transient stability margin under a wide range of operating conditions.      

智能电网中电力线通信网络负载均衡的机会路由协议

针对智能电网（SG）中电力线通信（PLC）网络中负载均衡的问题,提出了一个自适应机会路由协议——负载均衡的机会路由协议（LBORP）。在LBORP中,所有收到数据包的候选转发节点都有机会参与到数据包的转发中,不再局限于一条路由路径,避免了流量仅从一条链路经过导致的负载不均衡现象;而且候选转发节点的转发优先级不仅考虑到转发节点到目的节点的距离,还考虑到了PLC链路的不稳定性以及流量的变化。除此之外,在LBORP中采用一种隐式确认方案,进一步减少协议的端到端时延。在仿真实验中,与基于有序树的PLC路由协议（PLC-TR）和PLC机会路由协议（PLC-OR）相比,LBORP在时延上分别降低了19.7%和45.8%,在丢包率上分别降低了23.4%和32.5%。实验结果表明,LBORP能够实现网络的负载均衡,提升网络的可靠性并减小端到端时延。     

Prototyping virtual reality serious games for building earthquake preparedness: The Auckland City Hospital case study

Enhancing evacuee safety is a key factor in reducing the number of injuries and deaths that result from earthquakes. One way this can be achieved is by training occupants. Virtual Reality (VR) and Serious Games (SGs), represent novel techniques that may overcome the limitations of traditional training approaches. VR and SGs have been examined in the fire emergency context; however, their application to earthquake preparedness has not yet been extensively examined.We provide a theoretical discussion of the advantages and limitations of using VR SGs to investigate how building occupants behave during earthquake evacuations and to train building occupants to cope with such emergencies. We explore key design components for developing a VR SG framework: (a) what features constitute an earthquake event; (b) which building types can be selected and represented within the VR environment; (c) how damage to the building can be determined and represented; (d) how non-player characters (NPC) can be designed; and (e) what level of interaction there can be between NPC and the human participants. We illustrate the above by presenting the Auckland City Hospital, New Zealand as a case study, and propose a possible VR SG training tool to enhance earthquake preparedness in public buildings.     

A comprehensive layered approach for implementing internet of things-enabled smart grid: A survey

The current power grid confronts severe challenges in satisfying customers' demands. Fast transition to the much more flexible power grid enriched with renewable energies, micro-grid, and distributed energy resources has been considered as a straightforward solution to the customers’ high demand. Using smart equipment and renewable energies, electric power generation and storage through the power grid domains will be facilitated, which enables bi-directional energy and information flows. The power grid with such enhanced features is called Smart Grid (SG). Controlling and managing the diverse sets of variables in the SG requires precise measuring, monitoring, communicating, and analytic systems which increase the complexity of the grid. This complexity is the main barrier to the realization of the SG up to now. The emergence of the Internet of Things (IoT) simplifies monitoring, communications, and data processing among smart things to connect to anything in the world. This motivates the SG stakeholders and researchers to proceed with the best way to exploit the IoT technologies in the SG. In this survey paper, we summarize various efforts in this regard to highlight the advantages of the IoT-enabled SG and its probable gaps. To this end, a comprehensive layered approach has been proposed in this paper to classify various applications of the IoT technologies in the SG. Investigating IoT opportunities in each architecture layer facilitates the role of each technology and its relationship with other technologies. Also, open issues and future measures for the realization of IoT-enabled SG have been discussed in the paper.     

增殖型溶瘤腺病毒SG511-pHSP70-IL24体外杀伤肝癌细胞的研究

研究溶瘤腺病毒SG511携带由热激蛋白70(hsp70)启动子调控IL-24构成的增殖型溶瘤腺病毒SG511-pHSP70-IL24对人肝癌细胞株的体外杀伤效果.实验采用ELISA法检测不同MOI值感染肝癌细胞SMMC-7721和Hep3B细胞3 d后IL-24的表达;MTT法检测SG511、Ad11-IL24以及SG511-pHSP70-IL24对肝癌细胞株SMMC-7721、Hep3B以及人正常成纤维细胞株MRC-5及BJ增殖的抑制作用;并通过结晶紫实验检测进一步证明联合用药对肿瘤细胞的杀伤情况.ELISA检测到SG511-pHSP70-IL24感染SMMC-7721和Hep3B细胞后,IL-24有明显表达;MTT实验结果表明SG511-pHSP70-IL24对肿瘤细胞的杀伤能力比SG511和Ad-IL24更强.同时结晶紫实验也证明了SG511-pHSP70-IL24对肿瘤细胞的杀伤能力比SG511和Ad-IL24更强.增殖型溶瘤腺病毒SG511-pHSP70-IL24相比腺病毒Ad11-IL24以及SG511,对肝癌细胞有较明显的生长抑制和凋亡诱导作用.     

一种升/降压斩波器与可逆PWM调速相兼容的实验电路设计

本文分析了升/降压斩波电路、可逆PWM调速电路的工作原理,给出了一种升/降压斩波与可逆PWM调速相兼容的实验电路,并介绍了其实验内容、要求、实验特性和实验操作方法。     

基于软交换体系下的VolP技术的研究与设计

VoIP如何与下一代网络融合是目前比较热门的讨论话题,由于目前基于网关一网守（G、nGK）的VoIP网络中网关功能过于集中,设备过于复杂以及容量受限的问题,本文将借助软交换的业务／控制与传送／接入分离的思想,将网关分离使网关只负责媒体的传输,呼叫控制功能由软交换设备来完成,不仅解决了容量问题,而且易于维护和管理。     

Computational simulation of microstructure evolution during solidification of ductile cast iron

Abstract

This paper presents a thermomicrostructural model for the simulation of the solidification process of an eutectic ductile cast iron. The thermal balance is written at a macroscopic level and takes into account both the structural component being cast and its mould. Models of nucleation and growth represent the evolution of the microstructure, and the microsegregation of silicon is also considered. The resulting formulation is solved using a finite element discretisation of the macrodomain, in which the evolution of the microstructure is taken into account at the Gauss integration points. The numerical results are presented in terms of cooling curves and are compared with available experimental values. Furthermore, the sensitivity of the response with respect to changes in the cooling rate and nucleation parameters are investigated. The agreement between experimental and computational values is acceptable in both quantitative and qualitative aspects. Ways to improve the computational model are suggested.     

太阳能电动车电源控制系统的研究

分析了太阳能电动车现状，设计了一种太阳能电动车电源电路，同时，利用SG3525芯片设计了蓄电池boost电路，满足了电动车的负载需求。该系统具有效率高、响应快、稳定性好等优点，很好地满足了太阳能电动车供电需求。