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Differential evolution based computation intelligence solver for elliptic partial differential equations

Frontiers of Information Technology & Electronic Engineering 2019年第10期20卷 1445-1456页

作者： Muhammad Faisal FATEH Aneela ZAMEER Sikander MMIRZA Nasir mmirza Muhammad Saeed ASLAM Muhammad Asif Zahoor RAJA Department of Electrical Engineering Pakistan Institute of Engineering and Applied Sciences(PIEAS)Islamabad 45650Pakistan Department of Computer and Information Sciences Pakistan Institute of Engineering and Applied Sciences(PIEAS)Islamabad 45650Pakistan Department of Physics and Applied Mathematics Pakistan Institute of Engineering and Applied Sciences(PIEAS)Islamabad 45650Pakistan School of Electrical and Electronic Engineering University of AdelaideAdelaide 5005Australia Department of Electrical and Computer Engineering COMSATS University IslamabadAttock CampusAttock 43600Pakistan

A differential evolution based methodology is introduced for the solution of elliptic partial differential equations (PDEs) with Dirichlet and/or Neumann boundary conditions. The solutions evolve over bounded domains throughout the interior nodes by minimization of nodal deviations among the population. The elliptic PDEs are replaced by the corresponding system of finite difference approximation, yielding an expression for nodal residues. The global residue is declared as the root-mean-square value of the nodal residues and taken as the cost function. The standard differential evolution is then used for the solution of elliptic PDEs by conversion to a minimization problem of the global residue. A set of benchmark problems consisting of both linear and nonlinear elliptic PDEs has been considered for validation, proving the effectiveness of the proposed algorithm. To demonstrate its robustness, sensitivity analysis has been carried out for various differential evolution operators and parameters. Comparison of the differential evolution based computed nodal values with the corresponding data obtained using the exact analytical expressions shows the accuracy and convergence of the proposed methodology.

关键词： Differential evolution Boundary value problems Partial differential equation Finite difference scheme Numerical computing

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城市范围内的实时出租车共享方法研究

城市范围内的实时出租车共享方法研究

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作者： Ammar sikander 华北电力大学(北京)

学位级别：硕士

随着市中心的不断扩大,我们对有效的交通路线的需求不断增长,为了克服这一问题,共享出行和组合出行的方式被提出,用于多个用户间共享出行和共享交通工具。但共享出行需要实时、快速处理大量的用户请求,针对这一问题,现有的策略多是在优... 详细信息

随着市中心的不断扩大,我们对有效的交通路线的需求不断增长,为了克服这一问题,共享出行和组合出行的方式被提出,用于多个用户间共享出行和共享交通工具。但共享出行需要实时、快速处理大量的用户请求,针对这一问题,现有的策略多是在优化层次进行改进,而我们将使用一种并行化、分组的策略,通过使用这些快速、成熟的研究方法,使得我们能够在数秒钟处理大量的出行请求。为了进一步提高计算速度,我们对乘客进行分组,以出行起点基础,根据不同出行目标,将原有问题划分成多个子问题,每个子问题包含一定量的乘客。为了加快找到每个子问题的解决方案,我们采用邻域搜索的算法,并提出变邻域搜索技术来解决小实例请求问题。最后使用这一套方案同时处理5000条拼车请求,有效地管理纽约曼哈顿的出行拼车。在仿真实验中,验证了我们的方法只需要很小的响应时间就能对用户进行处理,从而使得实时出行共享变得更加便利。

关键词：出租车共乘本地搜索聚类大邻域搜索

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光场粒子图像测速技术在超音速射流中的实验研究和验证

光场粒子图像测速技术在超音速射流中的实验研究和验证

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作者： sikander Sheikh 上海交通大学

学位级别：硕士

光场粒子图像测速(light-field particle image velocimetry,LFPIV)是一种新兴且有发展潜力的单相机三维流场测量技术。现存的其他三维粒子图像测速技术有以下几个局限性:(1)实验设备复杂,(2)设备占用空间大,(3)处理时间长和(4)基于多... 详细信息

光场粒子图像测速(light-field particle image velocimetry,LFPIV)是一种新兴且有发展潜力的单相机三维流场测量技术。现存的其他三维粒子图像测速技术有以下几个局限性:(1)实验设备复杂,(2)设备占用空间大,(3)处理时间长和(4)基于多相机系统。本文提出利用LFPIV来规避上述局限性。文中介绍了使用LFPIV来精确获取超声速射流三维速度场的实验,借以初次验证LFPIV在高速可压缩流体中的可行性。在此之前,LFPIV仅被应用在低速射流和涡流中。为了验证整个系统的功效,采取了以下的验证手段:(1)定性验证,即对比纹影结果中超声速射流的激波结构和马赫环以及(2)定量验证,即对比二维PIV中超声速射流的剖面速度分布图和马赫数分布,两者结果的误差约为1%。在本文涉及的研究中,超音速喷嘴是基于双半径法和特征线法来设计的。为了验证喷嘴出口处均匀激波的存在,画出了喷嘴的二维计算模型并在此基础上通过ANSYS来模拟。同时还在低、中、高的精细度条件下进行了网格无关性测试。在本文的实验中,使用了总计三套设备来做定性和定量的分析:(1)纹影实验,(2)二维PIV(粒子为直径1μm的氧化铝颗粒)和(3)LFPIV实验(粒子为直径0.5μm的氧化铝颗粒)。基于镜面纹影的实验研究使用了水平和竖直两组刀片,其结果表明所设计喷嘴外的流动具有过膨胀、完美膨胀和欠膨胀的特性。结果也可用来提取激波几何结构,以便在之后的实验中对比定性验证LFPIV的测量。利用二维PIV对该超音速射流做实验研究,从150个拍摄处理得到的瞬态速度场中得出平均速度在y方向上和x方向上的值。其中,计算获得的y方向上平均马赫数为0.9-1.2,整个射流(含外部边界区域)的速度范围约为280m/s至384m/s。最后,利用新兴且具有创新性的LFPIV初测测量超音速射流,其结果马赫数约为0.9-1.2,整个射流(含外部边界区域)的速度范围为231m/s至385m/s。此结果通过与二维PIV结果的对比得到了验证。此外,还在概率分布函数和累计概率分布函数上开展了速度差异分析。二维PIV与LFPIV的速度绝对值差异大约为1%,马赫数分布差异大约为1.2%,表明了两者的结果具有相似性、可比性。本文的创新点在于:(1)首次验证了LFPIV在超声速可压缩流体中的应用,(2)设计了超声速喷嘴,并基于此开展纹影、二维PIV和三维PIV实验,(3)在受限光学窗口系统中使用LFPIV,即用单相机实现超音速射流三维速度场测量,(4)通过紧凑的单相机系统获得了与其他多相机三维PIV技术可比的结果,(5)定量定性地比较分析了二维PIV和LFPIV所获的结果。

关键词：光场成像三维粒子图像测速技术超音速射流纹影二维PIV 光场PIV

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Converters Techniques for Pv Power Generation in DC Microgrid

Converters Techniques for Pv Power Generation in DC Microgri...

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作者： sikander Ali 河北工业大学

学位级别：硕士

太阳能是一种清洁、安全和环保可再生能源,但应用中面临着效率低下、大规模利用程度低的问题。文中针对光伏变换器运行控制问题,完成了以下两个工作:（1）提出了一种改进的最大功率点跟踪（MPPT）控制器跟踪算法;（2）完成了一种用于能... 详细信息

太阳能是一种清洁、安全和环保可再生能源,但应用中面临着效率低下、大规模利用程度低的问题。文中针对光伏变换器运行控制问题,完成了以下两个工作:（1）提出了一种改进的最大功率点跟踪（MPPT）控制器跟踪算法;（2）完成了一种用于能量共享的直流微电网中并联降压变换器的一次和二次控制器设计。具体如下:o MPPT技术是一种应用于光伏发电（PVS）中最大功率跟踪方法。传统的MPPT方法面临的主要挑战是由于跟踪过程中固定步长而导致的固定稳态振荡和动态慢功率跟踪。Beta方法可以利用中间参数“Beta”在暂态中得到可变步长从而来解决这些问题。然而,为了提高效率,需要对该方法的一些参数进行优化。修正原有的Beta法的主要目的是使稳态振荡最小化,并快速跟踪瞬态最大功率。从卡拉奇市1年的气候数据中集中提取了最高辐照度、平均辐照度和温度水平等必要的气候信息,建立了Beta极限值,提出了一种带有升压变换器的改进的Beta法的PLECS模型,并进行了数值模拟,取得了良好的结果。o直流微电网（MG）由于其对可再生能源的大规模高效应用而成为具有广泛应用前景的微电网。在直流微电网的分级控制中,通常在一级控制中采用V-I下垂控制,以实现分担变换器之间的共同负载。然而,由于变换器之间存在下垂和线路电阻,传统的下垂控制会导致不适当的电流分配、电压变化以及环流调节。本文根据时间常数和时滞的概念,提出了电流模式控制中Buck变换器的初级控制设计,并结合低带宽通信（LBC）、循环电流最小化技术和平均电压/电流控制等方法,对分布式并联运行进行了二次控制设计。此外,两个转换器使用不同的时间延迟来验证通讯延迟对电流分配和电压恢复的影响。在PLECS的环境下,对2X2.5KWdc并联降压变换器进行了仿真,结果表明,该方法在减小循环电流、提高均衡的分配电流和恢复电网电压等方面取得了良好的效果。

关键词： MPPT 可变步长比例因数直流微电网分级控制分布式二次控制

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Hybrid Energy Storage to Control and Optimize Electric Propulsion Systems

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Computers, Materials & Continua 2022年第6期71卷 6183-6200页

作者： sikander Hans Smarajit Ghosh Suman Bhullar Aman Kataria Vinod Karar Divya Agrawal Department of Electrical and Instrumentation Engineering Thapar Institute of Engineering&TechnologyPatialaIndia Optical Devices and Systems CSIR-Central Scientific Instruments OrganizationChandigarh 160030India

Today,ship development has concentrated on electrifying ships in commercial and military applications to improve efficiency,support highpower missile systems and reduce emissions.However,the electric propulsion of the shipboard system experiences torque fluctuation,thrust,and power due to the rotation of the propeller shaft and the motion of waves.In order tomeet these challenges,a new solution is needed.This paper explores hybrid energy management systems using the battery and ultracapacitor to control and optimize the electric propulsion system.The battery type and ultracapacitor are ZEBRA and MAXWELL,respectively.The 3-,4-and 5-blade propellers are considered to produce power and move rapidly.The loss factor has been reduced,and the sea states have been found through the Elephant Herding Optimization algorithm.The efficiency of the proposed system is greatly enhanced through torque,thrust and power.The model predictive controller control strategy is activated to reduce load torque and drive system Root Average Square(RMS)error.The implementations are conducted under the MATLAB platform.The values for torque,current,power,and error are measured and plotted.Finally,the performance of the proposed methodology is compared with other available algorithms such as BAT and Dragonfly(DF).The simulation results show that the results of the proposed method are superior to those of various techniques and algorithms such as BAT and Dragonfly.

关键词： Dynamic model of the ship elephant herding optimization energy management schemes propeller ultra-capacitor zebra batteries

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Influence of thyroid volume reduction on absorbed dose in ^(131)I therapy studied by using Geant4 Monte Carlo simulation

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Chinese Physics C 2014年第5期38卷 62-68页

作者： Ziaur Rahman sikander M Mirza Waheed Arshed Nasir M Mirza Waheed Ahmed Health Physics Division Pakistan Institute of Nuclear Science and Technology Department of Physics and Applied Mathematics Pakistan Institute of Engineering and Applied Sciences

A simulation study has been performed to quantify the effect of volume reduction on the thyroid absorbed dose per decay and to investigate the variation of energy deposition per decay due to β- and γ-activity of 131I with volume/mass of thyroid, for water, ICRP- and ICRU-soft tissue taken as thyroid material. A Monte Carlo model of the thyroid, in the Geant4 radiation transport simulation toolkit was constructed to compute the β- and γ-absorbed dose in the simulated thyroid phantom for various values of its volume. The effect of the size and shape of the thyroid on energy deposition per decay has also been studied by using spherical, ellipsoidal and cylindrical models for the thyroid and varying its volume in 1-25 cm3 range. The relative differences of Geant4 results for different models with each other and MCNP results lie well below 1.870%. The maximum relative difference among the Geant4 estimated results for water with ICRP and ICRU soft tissues is not more than 0.225%. S-values for ellipsoidal, spherical and cylindrical thyroid models were estimated and the relative difference with published results lies within 3.095%. The absorbed fraction values for beta particles show a good agreement with published values within 2.105% deviation. The Geant4 based simulation results of absorbed fractions for gammas again show a good agreement with the corresponding MCNP and EGS4 results （±6.667%） but have 29.032% higher values than that of MIRD calculated values. Consistent with previous studies, the reduction of the thyroid volume is found to have a substantial effect on the absorbed dose. Geant4 simulations confirm dose dependence on the volume/mass of thyroid in agreement with MCNP and EGS4 computed values but are substantially different from MIRD8 data. Therefore, inclusion of size/mass dependence is indicated for 131I radiotherapy of the thyroid.

关键词： mean absorbed dose rate Geant4 Monte Carlo simulation and 131I therapy

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Fuel loading pattern optimization of a pressurized water reactor by varying internal weights-based particle swarm optimization

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Nuclear Science and Techniques 2018年第3期29卷 61-70页

作者： Aneela Zameer sikander M.Mirza Asifullah Khan Furqan Mir Department of Computer and Information Sciences Pakistan Institute of Engineering and Applied Sciences (PIEAS) Department of Physics and Applied Mathematics Pakistan Institute of Engineering and Applied Sciences (PIEAS) Department of Nuclear Engineering Pakistan Institute of Engineering and Applied Sciences (PIEAS)

Fuel reload pattern optimization is essential for attaining maximum fuel burnup for minimization of generation cost while minimizing power peaking factor(PPF).The aim of this work is to carry out detailed assessment of particle swarm optimization(PSO) in the context of fuel reload pattern search. With astronomically large number of possible loading patterns, the main constraints are limiting local power peaking factor, fixed number of assemblies,fixed fuel enrichment, and burnable poison rods. In this work, initial loading pattern of fixed batches of fuel assemblies is optimized by using particle swarm optimization technique employing novel feature of varying inertial weights with the objective function to obtain both flat power profile and cycle k_(eff)>1. For neutronics calculation, PSU-LEOPARD-generated assembly depletiondependent group-constant-based ADD files are used. The assembly data description file generated by PSU-LEOPARD is used as input cross-section library to MCRAC code, which computes normalized power profile of all fuel assemblies of PWR nuclear reactor core. The standard PSO with varying inertial weights is then employed to avoid trapping in local minima. A series of experiments havebeen conducted to obtain near-optimal converged fuelloading pattern of 300 MWe PWR Chashma reactor. The optimized loading pattern is found in good agreement with results found in literature. Hybrid scheme of PSO with simulated annealing has also been implemented and resulted in faster convergence.

关键词： PWR Loading pattern optimization PSO PPF In-core fuel management

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Controller Placement in Software Defined Internet of Things Using Optimization Algorithm

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Computers, Materials & Continua 2022年第3期70卷 5073-5089页

作者： sikander Hans Smarajit Ghosh Aman Kataria Vinod Karar Sarika Sharma Department of Electrical and Instrumentation Engineering Thapar Institute of Engineering&TechnologyPatialaIndia Optical Devices and Systems CSIR-Central Scientific Instruments OrganizationSector 30-CChandigarh160030India Department of Electrical Engineering Government PolytechnicAmbala CityAmbala134003India

The current and future status of the internet is represented by the upcoming Internet of Things(IoT).The internet can connect the huge amount of data,which contains lot of processing operations and efforts to transfer the pieces of information.The emerging IoT technology in which the smart ecosystem is enabled by the physical object fixed with software electronics,sensors and network connectivity.Nowadays,there are two trending technologies that take the platform i.e.,Software Defined Network(SDN)and IoT(SD-IoT).The main aim of the IoT network is to connect and organize different objects with the internet,which is managed with the control panel and data panel in the SD network.The main issue and the challenging factors in this network are the increase in the delay and latency problem between the controllers.It is more significant for wide area networks,because of the large packet propagation latency and the controller placement problem is more important in every network.In the proposed work,IoT is implementing with adaptive fuzzy controller placement using the enhanced sunflower optimization(ESFO)algorithm and Pareto Optimal Controller placement tool(POCO)for the placement problem of the controller.In order to prove the efficiency of the proposed system,it is compared with other existing methods like PASIN,hybrid SD and PSO in terms of load balance,reduced number of controllers and average latency and delay.With 2 controllers,the proposed method obtains 400 miles as average latency,which is 22.2%smaller than PSO,76.9%lesser than hybrid SD and 91.89%lesser than PASIN.

关键词： SD-IoT adaptive fuzzy controller enhanced sunflower optimization(ESFO) POCO placement tool controller placement problem and minimum latency

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Evaluation of Corrosion Product Activity in a Typical PWR with Extended Cycles and Flow Rate Perturbations

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World Journal of Nuclear Science and Technology 2017年第1期7卷 24-34页

作者： Rubina Nasir sikander M. Mirza Nasir M. Mirza Department of Physics Air University Islamabad Pakistan Department of Physics & Applied Mathematics Pakistan Institute of Engineering & Applied Sciences Islamabad Pakistan

Effect of flow rate perturbations has been studied using the modified computer program CPAIR-P for time dependent corrosion rates in Pressurized Water Reactors (PWRs) having extended cycles. In these simulations, a decrease in the corresponding saturation values of corrosion product activity (CPA) is observed for higher pH values. Comparison of CPA’s behavior has been done for constant flow-rate case as well as for transients with elevated 10B levels (~40%) in dissolved boric acid in coolant in two operating cycles. When the flow rate is decreased in the first cycle, the saturation value of CPA attains new higher values. Also, in the second operating cycle, the saturation values are about 12% higher when compared with the values in the first cycle.

关键词： PWRs Corrosion Products Enriched Boric Acid Extended Cycles Flow Rate Perturbations

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不同耕作措施下夏玉米生长季农田CO_2排放速率及其与土壤温度的关系

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西北农业学报 2013年第6期22卷 53-59页

作者：禄兴丽 sikander Khan Tanveer 廖允成温晓霞西北农林科技大学农学院陕西杨凌712100

采用定位试验,系统研究翻耕(CT)、旋耕(RT)、免耕不覆盖(NT)3种不同耕作措施下土壤CO2排放速率,并对CO2排放速率和10cm土壤温度进行回归模拟。结果表明:夏玉米生育期CO2排放速率表现为翻耕(CT)>旋耕(RT)>免耕不覆盖(NT),平均分别为585.... 详细信息

采用定位试验,系统研究翻耕(CT)、旋耕(RT)、免耕不覆盖(NT)3种不同耕作措施下土壤CO2排放速率,并对CO2排放速率和10cm土壤温度进行回归模拟。结果表明:夏玉米生育期CO2排放速率表现为翻耕(CT)>旋耕(RT)>免耕不覆盖(NT),平均分别为585.675、457.875和184.95mg·m-2·h-1。并且3种耕作措施之间差异均达到显著水平(P<0.05);各处理夏玉米生育期CO2排放速率与土壤温度呈显著正相关;NT、RT和CT处理CO2排放速率与10cm地温相关系数分别为0.624、0.609和0.606。CO2排放速率和土壤温度呈指数函数关系(P<0.05),利用10cm地温对夏玉米生育期农田CO2排放通量进行估算表明,CT、RT和NT处理CO2排放量分别为1.47、1.15和0.46kg·m-2。

关键词：耕作措施夏玉米土壤CO2排放速率土壤温度

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