Secrecy Outage Probability Minimization in Wireless-Powered Communications Using an Improved Biogeography-Based Optimization-Inspired Recurrent Neural Network

This paper focuses on wireless-powered communication systems,which are increasingly relevant in the Internet of Things(IoT)due to their ability to extend the operational lifetime of devices with limited energy.The main contribution of the paper is a novel approach to minimize the secrecy outage probability(SOP)in these systems.Minimizing SOP is crucial for maintaining the confidentiality and integrity of data,especially in situations where the transmission of sensitive data is critical.Our proposed method harnesses the power of an improved biogeography-based optimization(IBBO)to effectively train a recurrent neural network(RNN).The proposed IBBO introduces an innovative migration model.The core advantage of IBBO lies in its adeptness at maintaining equilibrium between exploration and exploitation.This is accomplished by integrating tactics such as advancing towards a random habitat,adopting the crossover operator from genetic algorithms(GA),and utilizing the global best(Gbest)operator from particle swarm optimization(PSO)into the IBBO framework.The IBBO demonstrates its efficacy by enabling the RNN to optimize the system parameters,resulting in significant outage probability reduction.Through comprehensive simulations,we showcase the superiority of the IBBO-RNN over existing approaches,highlighting its capability to achieve remarkable gains in SOP minimization.This paper compares nine methods for predicting outage probability in wireless-powered communications.The IBBO-RNN achieved the highest accuracy rate of 98.92%,showing a significant performance improvement.In contrast,the standard RNN recorded lower accuracy rates of 91.27%.The IBBO-RNN maintains lower SOP values across the entire signal-to-noise ratio(SNR)spectrum tested,suggesting that the method is highly effective at optimizing system parameters for improved secrecy even at lower SNRs.

Optimal Bidding Strategies of Microgrid with Demand Side Management for Economic Emission Dispatch Incorporating Uncertainty and Outage of Renewable Energy Sources

In the restructured electricity market,microgrid(MG),with the incorporation of smart grid technologies,distributed energy resources(DERs),a pumped-storage-hydraulic(PSH)unit,and a demand response program(DRP),is a smarter and more reliable electricity provider.DER consists of gas turbines and renewable energy sources such as photovoltaic systems and wind turbines.Better bidding strategies,prepared by MG operators,decrease the electricity cost and emissions from upstream grid and conventional and renewable energy sources(RES).But it is inefficient due to the very high sporadic characteristics of RES and the very high outage rate.To solve these issues,this study suggests non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ)for an optimal bidding strategy considering pumped hydroelectric energy storage and DRP based on outage conditions and uncertainties of renewable energy sources.The uncertainty related to solar and wind units is modeled using lognormal and Weibull probability distributions.TOU-based DRP is used,especially considering the time of outages along with the time of peak loads and prices,to enhance the reliability of MG and reduce costs and emissions.

Outage Analysis of Optimal UAV Cooperation with IRS via Energy Harvesting Enhancement Assisted Computational Offloading

The utilization of mobile edge computing(MEC)for unmanned aerial vehicle(UAV)communication presents a viable solution for achieving high reliability and low latency communication.This study explores the potential of employing intelligent reflective surfaces(IRS)andUAVs as relay nodes to efficiently offload user computing tasks to theMEC server system model.Specifically,the user node accesses the primary user spectrum,while adhering to the constraint of satisfying the primary user peak interference power.Furthermore,the UAV acquires energy without interrupting the primary user’s regular communication by employing two energy harvesting schemes,namely time switching(TS)and power splitting(PS).The selection of the optimal UAV is based on the maximization of the instantaneous signal-to-noise ratio.Subsequently,the analytical expression for the outage probability of the system in Rayleigh channels is derived and analyzed.The study investigates the impact of various system parameters,including the number of UAVs,peak interference power,TS,and PS factors,on the system’s outage performance through simulation.The proposed system is also compared to two conventional benchmark schemes:the optimal UAV link transmission and the IRS link transmission.The simulation results validate the theoretical derivation and demonstrate the superiority of the proposed scheme over the benchmark schemes.

Multi-Layer Optimization for Load Scheduling to Manage Unreliable Grid Outages in Developing Countries

This paper describes the significant cost saving opportunities for consumers in developing countries by the use of computational intelligence and demand-side-management techniques to mitigate the massive use of diesel back-up during grid outages. Application of load scheduling optimization is investigated during scheduled power outages, for residential consumer in India. The specific load shifting approaches explored include a day ahead predicted load schedule which is generated by performing a DSM referring to the forecasted day ahead outage. Whereas in reality the predicted may not match the actual outage, thus in these cases a fuzzy logic rule base is referred on real time basis to take corrective action & reach the best optimal load schedule possible to attain the lowest cost. The load types modeled include passive loads and schedulable, i.e. typically heavy loads. It is found that this multi-level DSM schemes show excellent benefits to the consumer. The maximum diesel savings for the consumer due to load shifting can be approximately ranging from 45% to as high as 75% for a flat-tariff grid. The study also showed that the actual savings potential depends on the timing of power outage, duration and the specific load characteristics.

Bridging GPS outages of tightly-coupled GPS/SINS using GMDH neural network

A tightly coupled GPS （ global positioning system ）/SINS （ strap down inertial navigation system） based on a GMDH （ group method of data handling） neural network was presented to solve the problem of degraded accuracy for less than four visible GPS satellites with poor signal quality. Positions and velocities of the satellites were predicted by a GMDH neural network, and the pseudo ranges and pseudo range rates received by the GPS receiver were simulated to ensure the regular op eration of the GPS/SINS Kalman filter during outages. In the mathematical simulation a tightly cou pled navigation system with a proposed approach has better navigation accuracy during GPS outages, and the anti jamming ability is strengthened for the tightly coupled navigation system.

Investigating Practical Measures to Reduce Power Outages and Energy Curtailments

This work attempts to investigate some practical measures that may reduce severe power outages that lead to energy curtailments. The first step of this attempt is to explore, from the consumer’s perspective, the adverse effects of the energy curtailments that reflect enormous damages (tangible and intangible) to the residential sector in the city of Riyadh (the capital of the Kingdom of Saudi Arabia). The second step is to propose, analyze, and employ energy conservation strategies that lead to both energy conservation and costs savings. The study results show that some customers will suffer enormous tangible and intangible losses should these outages occur during specific times, seasons, and for prolonged durations. In order to reduce these power outages and hence mitigate their adverse effects and consequences, the study proposes proper practical measures and solutions without compromising the consumers’ needs, satisfaction, and convenience.

Analysis of Personnel Radiation Monitoring Results during NPP Outages

The article provides outcomes of efforts taken by the specialists of radiation safety departments of Ukrainian Nuclear Power Plants （NPPs） to optimize and decrease exposure doses of personnel performing works during outages at NPP units. The article is written based on many years＇ experience and analysis of radiation hazardous works performed during scheduled maintenance of NPP equipment. It highlights significance of planning radiation doses （dose quotas） and organization of pending works during outages based on lessons learned. The results of works allowed to give due consideration to training of NPP maintenance personnel, improvement of labour conditions, workplace setup and enhancement of radiation protection means.

Investigation of Large Capacity Boiler "Four Tube" Bursting and Leakage Outages

Since adopting reform and opening policy. the electric power industry in China developed rapidly. At present there are more than 200 units of 200 MW and above large generation units. Due to hasty development, problems are numerous, especially for the boilers. In the 1986-1990 period (Seventh Five-year Plan period), large capacity boiler outages accounted for 65.8% of all large units equipment outages, and "four tube"

Outage Behaviors of Active Intelligent Reflecting Surface Enabled NOMA Communications

Active intelligent reflecting surface(IRS)is a novel and promising technology that is able to overcome the multiplicative fading introduced by passive IRS.In this paper,we consider the application of active IRS to nonorthogonalmultiple access(NOMA)networks,where the incident signals are amplified actively through integrating amplifier to reflecting elements.More specifically,the performance of active/passive IRS-NOMA networks is investigated over large and small-scale fading channels.Aiming to characterize the performance of active IRSNOMA networks,the exact and asymptotic expressions of outage probability for a couple of users,i.e.,near-end user n and far-end user m are derived by exploiting a 1-bit coding scheme.Based on approximated analyses,the diversity orders of user n and user m are obtained for active IRS-NOMA.In addition,the system throughput of active IRS-NOMA is discussed in the delay-sensitive transmission.The simulation results are carried out to verify that:i)The outage behaviors of active IRS-NOMAnetworks are superior to that of passive IRS-NOMAnetworks;ii)As the reflection amplitude factors increase,the active IRS-NOMAnetworks are capable of furnishing the enhanced outage performance;and iii)The active IRS-NOMA has a larger system throughput than passive IRS-NOMA and conventional communications.

System Outage Probability and Diversity Analysis of a SWIPT Based Two-Way DF Relay Network Under Transceiver Hardware Impairments

This paper investigates the system outage performance of a simultaneous wireless information and power transfer(SWIPT)based two-way decodeand-forward(DF)relay network,where potential hardware impairments(HIs)in all transceivers are considered.After harvesting energy and decoding messages simultaneously via a power splitting scheme,the energy-limited relay node forwards the decoded information to both terminals.Each terminal combines the signals from the direct and relaying links via selection combining.We derive the system outage probability under independent but non-identically distributed Nakagami-m fading channels.It reveals an overall system ceiling(OSC)effect,i.e.,the system falls in outage if the target rate exceeds an OSC threshold that is determined by the levels of HIs.Furthermore,we derive the diversity gain of the considered network.The result reveals that when the transmission rate is below the OSC threshold,the achieved diversity gain equals the sum of the shape parameter of the direct link and the smaller shape parameter of the terminalto-relay links;otherwise,the diversity gain is zero.This is different from the amplify-and-forward(AF)strategy,under which the relaying links have no contribution to the diversity gain.Simulation results validate the analytical results and reveal that compared with the AF strategy,the SWIPT based two-way relaying links under the DF strategy are more robust to HIs and achieve a lower system outage probability.

Secrecy Outage Probability for Two-Way Integrated Satellite Unmanned Aerial Vehicle Relay Networks with Hardware Impairments

In this paper,we investigate the secrecy outage performance for the two-way integrated satellite unmanned aerial vehicle relay networks with hardware impairments.Particularly,the closed-form expression for the secrecy outage probability is obtained.Moreover,to get more information on the secrecy outage probability in a high signalto-noise regime,the asymptotic analysis along with the secrecy diversity order and secrecy coding gain for the secrecy outage probability are also further obtained,which presents a fast method to evaluate the impact of system parameters and hardware impairments on the considered network.Finally,Monte Carlo simulation results are provided to show the efficiency of the theoretical analysis.

“拉闸限电”事件原因和影响解析:公众评论大数据驱动视角

不同于现有定性理论研究与计量建模分析,本文以2021年“拉闸限电”事件为对象,基于群体智慧理论提出大数据驱动研究框架,集成社会网络分析、主题建模和情感分析等方法研究公众对事件的评论大数据,深入解析突发事件的原因和影响。研究表明:(1)公众对事件的评论聚焦在限电影响、奥论走向、限电原因和解决措施4个方面。(2)通过构建事件内外部归因体系,发现电力需求不断增加与煤炭供应紧张和可再生能源发电不足导致的电力供应减少之间的缺口是主因。(3)识别事件多维影响后发现高耗能企业面临转型压力,政府“一刀切”执行方式和多种误导性信息是引发负面情绪的诱因。本研究为制定突发事件典论引导策略提供了参考。

多用户全双工协作PNOMA系统非正交率控制及功率分配优化算法

传统NOMA系统远近用户设备(User Equipment,UE)之间在时频资源上信号完全重叠,以期获得最高的频率利用率,但其中UE之间的干扰也成为核心问题之一.部分NOMA(Partial NOMA,PNOMA)系统由于仅在部分频段实现NOMA共存,因此可以优化协调UE之间的干扰.相较于传统NOMA系统,PNOMA系统能够极大地降低非理想连续干扰相消(imperfect Successive Interference Cancellation,ipSIC)对于系统和速率的消极影响.基于全双工协作NOMA(Full Duplex Cooperative NOMA,FD-CNOMA)系统和PNOMA系统,本文提出了一种全双工协作部分NOMA(FDCPNOMA)方案以优化UE之间干扰,提高系统可达速率.考虑由一个基站和若干个远近UE构成的FD-CPNOMA系统,针对实际中存在非理想连续干扰消除问题,本文给出了UE配对、非正交率控制及功率分配的优化算法,并推导了此模型下UE中断概率闭式解.仿真结果表明,本文提出的UE配对方案性能优于其他三种配对方案,所提出的PNOMA系统最大可达速率均优于相应的传统NOMA系统,提出的FD-CPNOMA系统在低信噪比下的最大可达速率比半双工协作部分NOMA(HD-CPNOMA)系统和PNOMA系统分别高出95.42%、44.06%,并且在高信噪比下可以较好地实现UE间公平性和平均可达速率的折衷.

无线光通信中大气湍流噪声测量研究

光信号的强度闪烁、光斑漂移、光束扩展、到达角起伏等大气湍流现象会影响光信号在大气中的传输性能。本文将这种闪烁效应看作是光通信系统传输中的乘性噪声,推导了大气湍流乘性噪声模型,并进行了实验测量研究。结果表明:按照晴天、雾霾天、雪天、小雨天、中雨天、大雨天及阴天的顺序,湍流乘性噪声对光通信的通信质量影响加剧,大气折射率结构常数逐渐增大,噪声信号的偏斜度与陡峭度随之增加,导致光强信号的衰落概率变大;同时随着信噪比(signal-to-noise ratio,SNR)的增大,系统的中断概率逐渐减小;而在相同的SNR下,中断概率随着大气折射率结构常数的减小而减小。研究大气湍流噪声对无线光通信系统的影响具有重要的意义,它为大范围、高速的无线光通信技术带来重要的技术突破,对无线光通信技术的发展起到重要的作用。

基于混合协作NOMA的安全MEC能耗优化

非正交多址接入(non-orthogonal multiple access,NOMA)技术的广泛应用改变了传统物理层安全对用户传输速率的限制,在降低时延的同时会引起系统能耗增加。针对安全通信与降低能耗问题,提出一种基于混合协作NOMA的安全边缘计算传输方法。该方法对每个用户数据处理过程设计了多时隙混合协作方案,根据不同用户的信道条件分别设置卸载决策,保证用户间公平,并推导出系统保密中断概率的闭合表达式。然后以最小化系统能耗为目标,采用基于块坐标下降的三步迭代优化算法求得最优卸载方案。仿真结果显示,所提出的传输方法能在保证信息安全的条件下有效地减少系统能耗。

多用户协作NOMA系统中的最优中继选择策略

在多用户协作非正交多址接入(NOMA)系统中,针对传统中继转发方式单一,中断性能较差的问题,提出了一种基于混合译码/放大转发(HDAF)协议的改进式最优中继选择策略.该策略以中继能否成功解码信号为依据,将多个中继划分为DF候选中继子集与AF候选中继子集,并选出其中接收信噪比最高的中继参与协作.为了进一步提升系统的通信性能,本文还引入自动重传(ARQ)技术,提出了一种基于增量混合译码/放大转发(IHDAF)协议的中继选择策略.分别推导了两种策略下系统中断概率的闭式表达,并通过蒙特卡罗实验对不同策略的中断概率进行了仿真.结果表明,本文所提的两种策略相比于传统策略能够获得更低的中断概率,特别是IHDAF中继选择策略始终可以实现更佳的中断性能.

二次水断供核主泵屏蔽电机冷却水瞬态热分析

核主泵屏蔽电机在热态极端环境参数额定(简称热态额定)工况下,二次水突然断供(secondary water supply outage,SWSO)300 s时刻,一次下导轴承润滑水温不超过警报温度95℃是产品出厂的重要指标,研究该情况下热流场计算方法及各种参数随时间演变特性对于电机热安全非常重要。首先,以北方工厂冷态环境参数下额定(简称冷态额定)工况该电机SWSO前后稳/瞬态厂内测量入出口试验数据为边界条件,采用有限体积法,进行流场和温度场的流固耦合数值模拟,模拟值与试验值300 s时的误差为5.97%,验证了计算方法准确性。然后,数值反演热态额定工况SWSO一/二次冷却水的温度场随时间变化规律。结果表明:SWSO 300 s内,二次水流速及对流传热系数随时间变化存在特征明显不同的2个阶段,二次水与螺旋槽壁面间对流换热系数h由稳态时7808.06 W/(m^(2)⋅K),13 s内减少到480.07 W/(m^(2)⋅K),随后h变化很小;热态额定参数时,下导轴承润滑水温远低于报警值95℃。为核主泵屏蔽电机轴承润滑水热安全计算提供参考。

一种接触网停电检修接地线接地可靠性检测方法

挂接地线是接触网停电检修作业的关键环节,为电力检修提供有效保障。为进一步加强电力检修作业的安全风险管控,针对在接触网停电检修作业时现有检测装置无法检测接地线是否可靠接地的问题,提出一种利用接触线上的残余电荷和感应电压来检测接地线是否可靠接地的方法。建立单线区段和复线区段停电检修挂接地线时的等效电路模型,并将接触线的残余电荷和“V”形天窗检修的感应电压作为等效激励源,对接地线电流进行理论计算;研制基于该文方法的接地线接地状态检测装置,用以判断接地线是否良好接地;通过所搭建的电流发生平台进行实验,并通过LoRa自组网与原有系统通信,在后台远程监测接地线的状态信息。实验结果验证了所提方法的可行性。

基于马尔科夫模型的双站激光微波混合链路性能分析

针对气象变化对自由空间光(Free Space Optical,FSO)通信链路和毫米波射频(Radio Frequency,RF)通信链路可用率的影响问题,采用马尔科夫建模与稳态概率求解计算方法,分析不同天气条件下FSO/RF混合链路的双接收站分集与中断概率性能.基于FSO链路和RF链路的信道模型,采用有限状态马尔科夫链(Finite State Markov Chain,FSMC)分别对单双站FSO/RF混合链路的切换选择进行建模,推导得出不同参数和天气情况下系统稳态的中断概率表达式.数值计算结果表明,当中断概率达到10^(-6),雨雾天气链路距离为1~7 km时,双站FSO/RF混合链路相比单站可获得4~25 dB的增益.

非理想干扰消除全双工协作NOMA系统性能分析及功率分配

随着非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术的不断发展,协作NOMA(Cooperative Non-Orthogonal Multiple Access,CNOMA)也受到广泛关注.该文研究了由一个基站(Base Station,BS)、一个远端用户和一个近端用户组成的全双工(Full-Duplex,FD)协作NOMA(FD-CNOMA)系统,其中近端用户作为一个FD解码转发中继以传输远端用户的信号.考虑实际情况中存在基站与远端用户有无直接链路两种情况,以及非理想连续干扰消除(Successive Interference Cancellation,SIC)对系统带来的残留干扰问题,该文提出并解决了在该模型下用户的功率分配问题.最后,该文基于此模型给出了中继用户和远端用户的中断概率闭式表达式和遍历速率的近似闭式表达式.理论分析与仿真结果表明,即便存在非理想SIC和自干扰,相对于半双工(Half-Duplex,HD)协作NOMA(HDCNOMA)和NOMA系统而言,FD-CNOMA系统表现出更好的系统性能.同时,非理想SIC和中继用户自干扰都会对用户性能产生负面影响,且非理想SIC在遍历速率上对HD机制的影响较FD机制更为严重.最后,文中提出的功率分配方法较随机功率分配和固定功率分配分别获得了13%和10%的速率提升.