A Novel Security Scheme for the Smart Grid and SCADA Networks

Supervisory control and data acquisition (SCADA) are applications that collect data from a system in order to automate the monitoring and controlling of its activities. Several industrial fields such as, electric utilities, water supplies and buildings’ facilities have already adopted SCADA systems to increase the efficiency and reduce cost. However, the IT community is concerned about the level of security that any applied SCADA system provides. This paper concentrates on the major security threats encountered in SCADA systems. In addition, it discusses a new proposed methodology in order to increase the system security with minimal impact on efficiency. The proposed scheme provides several security services which are mutual authentication, confidentiality, data integrity and accountability.     

Modified CAZAC Sequence Based Timing Synchronization Scheme for OFDM System

Wireless Personal Communications - Active queue management schemes are used to reduce the number of dropped packets at the routers. Random early detection uses dropping probability which is...     

Max-SINR Based Timing Synchronization Scheme in Hexagonal Multicarrier Transmission

In this paper, the maximizing Signal-to-Interference-plus-Noise Ratio (Max-SINR) criterion is applied in Hexagonal Multicarrier Transmission (HMT) system for timing synchronization. An iterative approach for Max-SINR timing over doubly dispersive (DD) channel with exponential power delay profile and U-shape Doppler spectrum is proposed. Theoretical analysis shows that there is an allowable SINR gap between the mean delay of DD channel and the optimal timing point. Meanwhile, a low complexity suboptimal timing approach based on instantaneous channel frequency response is proposed. Theoretical analysis and simulation results show that Max-SINR timing scheme outperforms traditional timing method about 2–15 dB in SINR and the suboptimal timing algorithm achieves a smaller Mean Square Error than 10^?4 over DD channels. In addition, the Iterative Projection Sequence Detection (IPSD) receiver is proposed and the Match Filter Low Bound (MFLB) in HMT system is given. Simulation results show that the Bit Error Rate (BER) of the proposed IPSD approach based on iterative Max-SINR timing approximates to the MFLB and outperforms traditional timing scheme about 3dB at BER = 10^?3.     

面向智慧城市应用的人工智能服务运营方案探讨

针对面向智慧城市应用的人工智能服务的研发、部署和访问,以及智慧城市数据安全与隐私保护问题,分析智慧城市应用使用人工智能服务的主要服务模式,在此基础上,提出一种人工智能服务开放平台,并介绍其主要特征、参考框架和应用方法。文章提出的人工智能服务开放平台有利于人工智能服务赋能智慧城市应用,有利于智慧城市数据的安全与隐私保护,有利于智慧城市应用提供商和人工智能服务提供商共同向用户提供价值服务。     

一种可靠的OFDM系统时间和频率同步方案

在无线信道中,由于多径和频偏的存在,影响了OFDM系统中同步的准确性.结合中国移动多媒体广播(CMMB)信道帧结构、调制及其信道,提出了一种适用于多径衰落信道、高频偏的OFDM系统时间和载波频率同步方案,能准确地完成帧同步和频偏估计.     

An Effective Timing Synchronization Scheme for DHTR UWB Receivers

In performing short-distance, high-data-rate wireless communications using ultra-wideband (UWB) systems, it is necessary to reduce the average transmission power and ensure a fixed synchronization error between the transmitter and receiver ends. Furthermore, to reduce multipath interference, the UWB system should be sometimes implemented using a rake receiver. However, for such receivers, the delay time and attenuation loss over each transmitted route must be known in advance. In the present study, the complexity of rake receivers with a large number of “fingers” is reduced by means of a delay-hopped transmitted-reference (DHTR) scheme, in which the delayed signal is correlated with the original signal; thereby avoiding the need for a separate template signal. The synchronization performance of the proposed DHTR receiver is analyzed both theoretically and numerically. An effective timing synchronization scheme, designated as “parallel signal acquisition with shared looped delay-line” (PS-SLD), is then proposed. The simulation results show that for multipath environments with a single user, the proposed synchronization scheme achieves a higher detection probability and a lower normalized mean square error (MSE) than the traditional timing dirty templates (TDT) algorithm.     

一种采用干扰抑制技术的Chirp超宽带同步算法

时间同步是Chirp超宽带通信系统的主要挑战之一。文章通过对直接调制方式下同步误差对系统误码率的影响进行分析,证明随着时间带宽积的增大,对同步算法的精度提出了更高的要求。而常用同步算法对噪声很敏感,文章利用干扰抑制的思想提出了一种新的同步算法。由于利用干扰抑制提高了信噪比,文章算法跟常用算法相比,可以使系统性能有较大提高。     

Smart Materials Enabled with Artificial Intelligence for Healthcare Wearables

Contemporary medicine suffers from many shortcomings in terms of successful disease diagnosis and treatment, both of which rely on detection capacity and timing. The lack of effective, reliable, and affordable detection and real-time monitoring limits the affordability of timely diagnosis and treatment. A new frontier that overcomes these challenges relies on smart health monitoring systems that combine wearable sensors and an analytical modulus. This review presents the latest advances in smart materials for the development of multifunctional wearable sensors while providing a bird's eye-view of their characteristics, functions, and applications. The review also presents the state-of-the-art on wearables fitted with artificial intelligence (AI) and support systems for clinical decision in early detection and accurate diagnosis of disorders. The ongoing challenges and future prospects for providing personal healthcare with AI-assisted support systems relating to clinical decisions are presented and discussed.     

Embedded TLS 1.2 Implementation for Smart Metering & Smart Grid Applications

Digital networked communications are the key to all Internet-of-Things applications, especially to smart metering systems and the smart grid. In order to ensure a safe operation of systems and the privacy of users, the transport layer security (TLS) protocol, a mature and well standardized solution for secure communications, may be used. We implemented the TLS protocol in its latest version in a way suitable for embedded and resource-constrained systems. This paper outlines the challenges and opportunities of deploying TLS in smart metering and smart grid applications and presents performance results of our TLS implementation. Our analysis shows that given an appropriate implementation and configuration, deploying TLS in constrained smart metering systems is possible with acceptable overhead.     

A New Timing Synchronization Metric for OFDM Based WLAN Systems

A new timing synchronization scheme for Orthogonal Frequency Division Multiplexing (OFDM) based Wireless Local Area Networks (WLANs) is presented. Specifically, use of one long OFDM symbol in the frame format of IEEE802.11a is suggested for coarse timing synchronization. A new timing metric has been proposed which results in significant improvement in performance compared to the results reported.     

面向智能电网应用的网络规划方法

传感器网络是智能电网和物联网的重要支持系统,贯穿智能电网输、变、配、用等各个环节。智能电网中各种传感器应用环境中对现有的移动网络具有多样化的需求。本文从智能电网中传感器网络需求出发,浅析满足智能电网无线网络规划和覆盖等要求的网络关键技术,给面向复杂智能电网通信环境下物联网大规模部署和可靠通信研究建议,从而实现智能电网中...     

An Adaptive Timing Synchronization Scheme for Multi-Band Orthogonal Frequency Division Multiplexing Based Ultra-Wideband Communication Systems

This article deals with a new energy based adaptive timing synchronization scheme (ATS) which estimates the symbol timing information within two (2) OFDM symbols and updates the information with different frequency bands (adaptive in sense) in a multi-band orthogonal frequency division multiplexing (MB-OFDM) based system. The new approach provides significant improvement in system performance for high delay spread ultra-wideband (UWB) channel model (CM) environments where fast and low-complexity timing synchronization is a critical issue. This paper also addresses a crucial aspect of UWB channel which is frequency dependent delay characteristics. This effect contributes to different dispersion and timing shift of an UWB signal for different frequency bands. In this work, the wideband channel delay characteristics are studied and delay parameters are found considerably different over frequency bands 3.1–4.6 GHz. Based on this observation, the ATS which estimates and maintains the timing delays of each band separately is presented. The performance of ATS algorithm is measured by mean-squared error (MSE), synchronization probability, signal to interference ratio (SIR) reduction due to synchronization errors and bit error rate (BER) through the computer simulation for several UWB CM environments CM2–CM4. Each of these UWB CMs is simulated for 100,000 noisy channel realizations for both coded and uncoded MB-OFDM system. It is shown that ATS gives signal-to-noise ratio (SNR) improvement of 1.1 dB at BER of 1 × 10⁻³, 1.2 dB at BER of 2 × 10⁻⁴, and 0.7 dB at BER of 2 × 10⁻⁴ for CM4, CM3, and CM2 respectively for coded MB-OFDM system over a non-adaptive synchronization scheme [Yak et al., Proceedings of IEEE PIMRC, Berlin, Germany, vol 1, pp 471–475, September 11–14, 2005].     

分布式认证智能电网访问控制模型的研究

为实现智能电网数据的安全汇总和访问控制的有效结合,在同态加密的基础上,结合陷门秘密分享技术,提出一种基于多方认证的智能电网访问控制方案。通过对智能电表中数据密文进行同态加密处理,保证数据从智能电表到变电站传输过程的安全,同时对汇总的密文数据进行属性化,可实现对数据访问者的多方认证访问控制。实验数据结果表明,该方案具有可行性和实用性。     

Super-Imposed Training Scheme for Timing and Frequency Synchronization in OFDM Systems

In this paper, a super-imposed scheme for timing and frequency synchronization is proposed for orthogonal frequency division multiplexing (OFDM) systems. The proposed architecture includes a pre-defined pseudo-noise (PN) sequence, which is added to both the OFDM symbol and the cyclic prefix (CP) in time domain. In contrast to existing synchronization schemes, the proposed architecture has the advantage of better bandwidth utilization since it does not require extra pilot symbols. The peak-to-average power ratio (PAPR) is also significantly decreased. Both the timing and frequency offset estimators are derived using the maximum likelihood (ML) criterion. Efficiencies of the estimators are analyzed mathematically in AWGN channels. Simulation experiments are also conducted in frequency selective fading channels. Moreover, the optimal power allocation factor of the PN sequence is determined by minimizing the bit error rate using simulation experiments     

An Adaptive Smart Grid Management Scheme Based on the Coopetition Game Model

Recently, the idea of the smart grid has been gaining significant attention and has become a hot research topic. The purpose of this paper is to present a novel smart grid management scheme that uses game theory principles. In our proposed scheme, power appliances in the smart grid adaptively form groups according to the non‐cooperative hedonic game model. By exploiting multi‐appliance diversity, appliances in each group are dynamically scheduled in a cooperative manner. For efficient smart grid management, the proposed coopetition game approach is dynamic and flexible to adaptively respond to current system conditions. The main feature is to maximize the overall system performance while satisfying the requirements of individual appliances. Simulation results indicate that our proposed scheme achieves higher energy efficiency and better system performance than other existing schemes.     

云计算在智能电网中的应用及其安全问题研究

文章认为在智能电网中引入云计算,构建智能电网云可以为智能电网的发展提供有效支持。基于智能电网的特征,依托作为一种崭新的存储和计算模式的云计算技术,文章阐述了云计算技术如何为智能电网的数据存储和分析提供技术支持,设计了一种智能电网云计算的结构,分析了云计算技术给智能电网带来的诸多益处;并就智能电网云可能存在的安全威胁和相应的防范措施进行讨论。     

基于多智能体深度强化学习的智能电网光网络切片方案

为了提高光网络对大规模、差异化电力业务的资源分配能力,降低大规模业务的算法训练时间,提出了一种基于多智能体深度确定性策略梯度算法的智能电网光网络资源分配方案。该方案考虑大规模和差异化电力业务,将智能电网光网络建模成多智能体系统,以最大化电网公司收益为目标,建立了智能电网光核心网络切片模型,进行网络资源分配优化,并采用条件判断映射,简化了优化问题。同时,把不同业务部署到不同智能体中进行运算,以降低训练时间,满足网络实时性需求。仿真结果表明,该算法具有更大的奖励、更低的成本、时延和训练时间。     

基于人工智能的网络智能化发展探讨

梳理了当前人工智能在通信领域的研究和应用进展,提出了中兴通讯基于人工智能的网络智能化解决方案。认为网络可以在网元智能、运维智能和业务智能3个层面引入人工智能(AI),并按照分层、按需、分阶段的引入原则,最终实现网络泛在智能。同时提出了一套多维度智能化分级标准,结合通信工作流程和智能化范围,将网络智能化水平分为5个等级,这将有助于网络逐步向目标架构演进。