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Improved Proximal Policy Optimization Algorithm for Sequential Security-constrained Optimal Power Flow Based on Expert Knowledge and Safety Layer

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 742-753页

作者： Yanbo Chen Qintao Du Honghai Liu Liangcheng Cheng Muhammad shahzad Younis State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources and School of Electrical&Electronic Engineering North China Electric Power UniversityBeijing 102206China School of Engineering Xining UniversityXining 810008Chinaand Key Laboratory of Smart Operation of New Energy Power SystemMinistry of EducationQinghai UniversityXining 810016China China Electric Power Research Institute Nanjing 210003China National University of Sciences and Technology Islamabad44000Pakistan

In recent years,reinforcement learning(RL)has emerged as a solution for model-free dynamic programming problem that cannot be effectively solved by traditional optimization *** has gradually been applied in the fields such as economic dispatch of power systems due to its strong selflearning and self-optimizing ***,existing economic scheduling methods based on RL ignore security risks that the agent may bring during exploration,which poses a risk of issuing instructions that threaten the safe operation of power ***,we propose an improved proximal policy optimization algorithm for sequential security-constrained optimal power flow(SCOPF)based on expert knowledge and safety layer to determine active power dispatch strategy,voltage optimization scheme of the units,and charging/discharging dispatch of energy storage *** expert experience is introduced to improve the ability to enforce constraints such as power balance in training process while guiding agent to effectively improve the utilization rate of renewable ***,to avoid line overload,we add a safety layer at the end of the policy network by introducing transmission constraints to avoid dangerous actions and tackle sequential SCOPF *** results on an improved IEEE 118-bus system verify the effectiveness of the proposed algorithm.

关键词： Sequential security-constrained optimal power flow(SCOPF) expert experience safety layer renewable energy safe reinforcement learning

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Developing a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) and its validation over the Northeast China Plain

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Journal of Integrative Agriculture 2021年第2期20卷 408-423页

作者： ZHANG Sha BAI Yun ZHANG Jia-hua shahzad ALI School of Automation Qingdao UniversityQingdao 266071P.R.China College of Computer Science and Technology Qingdao UniversityQingdao 266071P.R.China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China

Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations in conventional remote sensing(RS) approaches limited their applications over broad regions. In this study, a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) was developed to estimate regional maize yield, and it was implemented using eight data-model coupling strategies(DMCSs) over the Northeast China Plain(NECP). Simulations under eight DMCSs were validated against the prefecture-level statistics(2010–2012) reported by National Bureau of Statistics of China, and inter-compared. The 3-year averaged result could give more robust estimate than the yearly simulation for maize yield over space. A 3-year averaged validation showed that prefecture-level estimates by PRYM–Maize under DMCS8, which coupled with the development stage(DVS)-based grain-filling algorithm and RS phenology information and leaf area index(LAI), had higher correlation(R, 0.61) and smaller root mean standard error(RMSE, 1.33 t ha^(–1)) with the statistics than did PRYM–Maize under other DMCSs. The result also demonstrated that DVS-based grain-filling algorithm worked better for maize yield than did the harvest index(HI)-based method, and both RS phenology information and LAI worked for improving regional maize yield estimate. These results demonstrate that the developed PRYM–Maize under DMCS8 gives reasonable estimates for maize yield and provides scientific basis facilitating the understanding the spatial variations of maize yield over the NECP.

关键词： process-based and remote sensing model maize yield simulation development stage grain filling harvest index

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Magnetic Behaviour of Sm2Co7/Fe/Sm2 Co7, Nanocomposite Trilayers with Cr and Ti Additions

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Chinese Physics Letters 2009年第3期26卷 255-257页

作者： F. shahzad S. A. Siddiqi J. Zhou Advaaced Light Source Berkeley Lab University of California Berkeley CA 94720 USA Centre for Solid State Physics University of the Punjab Lahore-54590 Pakistan Department of Physics University of California Berkeley California 94720 USA

Trilayered Sm2Co7/Fe/Sm2Co7 spring exchange magnets are fabricated by dc magnetron sputtering on MgO substrates. Very thin layers （0.3-0.7 nm） of Cr and Ti are added at the interfaces of the two magnetic phases. The thickness of StucCo7 is kept at 20nm and Fe at 6nm while the thickness of Cr and Ti are varied as 0.3, 0.5, and 0.7nm. The base pressure of sputtering chamber is kept below 10^-7 Torr and Ar pressure at 3-8m Torr. The samples are characterized by x-ray diffraction （XRD） and SQUID magnetometer. We report improvement in exchange coupling of nonacomposite magnets by addition of thin layers of Cr at interfaces.

关键词： No English Keywords

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Fabrication and Characterization of SmCo5/Fe65Co35 and SmCo5/Fe Composite Spring Exchange Magnets

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Chinese Physics Letters 2008年第7期25卷 2642-2644页

作者： F. shahzad S. A. Siddiqi J. Zhou Centre for Solid State Physics University of the Punjab Lahore-54590 Pakistan Department of Physics University of California Berkeley California-P4720 USA

SmCo5/Fe65Co35 and SmCo5/Fe spring exchange magnets are fabricated by dc magnetron sputtering on MgO substrates and 100-nm-thick Si3N4 membranes, respectively. The base pressure of sputtering chamber is kept below 10^-7 Tort, and Ar pressure is 3 to 8mTorr. The samples are characterized by an x-ray diffractometer, a superconducting quantum interference magnetometer, and high resolution magnetic soft x-ray microscopy. We obtain the complete exchange coupling and single phase behaviour of composite magnets. The （BH）max value achieved is 28.8 MGOe.

关键词： the power-law exponents precipitation durative abrupt precipitation change

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Numerical Simulation of Reiner–Rivlin Nanofluid Flow under the Influence of Thermal Radiation and Activation Energy over a Rotating Disk

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Computer Modeling in Engineering & Sciences 2022年第6期131卷 1669-1692页

作者： Arfan shahzad Muhammad Imran Muhammad Nawaz Naeem Mohsan Raza Department of Mathematics Government College University FaisalabadFaisalabad38000Pakistan Department of Sciences&Humanities National University of Computer and Emerging SciencesChiniot-Faisalabad CampusFaisalabad38000Pakistan

In current study,the numerical computations of Reiner–Rivlin nanofluid flow through a rotational disk under the influence of thermal radiation and Arrhenius activation energy is *** innovative physical situations,the motile microorganisms are incorporated *** multiple slip effects are considered in the boundary *** bioconvection of motile microorganism is utilized alongside nanofluids to provide stability to enhanced thermal *** Bioconvection pattern in various nanoparticles accredits novel applications of biotechnology like the synthesis of biological polymers,biosensors,fuel cells,petroleum engineering,and the natural *** deploying some suitable similarity transformation functions,the governing partial differential equations(PDEs)of the flow problem are rehabilitated into dimensionless *** accomplished ordinary differential equations(ODEs)are solved numerically through the bvp4c scheme via a built-in function in computational MATLAB *** upshots of some prominent physical and bioconvection parameters including wall slip parameters,thermophoresis parameter,Brownian motion parameter,Reiner–Revlin nanofluid parameter,Prandtl number,Peclet number,Lewis number,bioconvection Lewis number,and the mixed convection parameter against velocity,temperature,nanoparticles concentration,and density of motile microorganism profiles are dichotomized and pondered through graphs and *** presented computations show that the velocity profiles are de-escalated by the wall slip parameters while the thermal and solutal fields are upgraded with augmentation in thermophoresis number and wall slip *** presence of thermal radiation enhances the temperature profile of *** concentration profile of nanoparticles is boosted by intensification in activation ***,the increasing values of bioconvection Lewis number and Peclet number decay the motile microorganisms’field.

关键词： Reiner-Rivlin nanofluid bioconvection motile swimming microorganisms rotational disk multiple slip conditions bvp4c

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Mass dependence of pion-induced fission cross sections on the level density parameter

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Chinese Physics C 2012年第9期36卷 831-835页

作者： Zafar Yasin Warda Iram M.Ikram shahzad Physics Division PINSTECHP.O.NiloreIslamabadPakistan Physics Department Islamia UniversityBahawalpurPakistan

Fission probabilities and fission cross sections strongly depend on the mass number of the target and energy of the projectile. In this research work, a cascade-exciton model （using CEM95 computer code） has been implemented to observe the dependence of pion-induced fission cross sections and fission probabilities on the target mass and ratio of the level density parameter in fission to neutron emission. The analysis has been performed for both the positive and negative pions as the projectile at 80, 100 and 150 MeV energies. The computed cross sections satisfactorily reproduced the experimental findings when compared with the available experimental data in the literature. We observed a smooth dependence at 150 MeV, and a sharper dependence at 80 and 100 MeV pion energy, in the fissility region above 29.44.

关键词： CEM95 fission cross section level density parameter

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Resource savings,recycling and utilization,and energy transition:Introduction

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Geoscience Frontiers 2024年第3期15卷 180-182页

作者： Xin Zhao Umer shahzad Aviral Kumar Tiwari School of Statistics and Applied Mathematics Anhui University of Finance and EconomicsBengbu 233030China School of Economics Széchenyi Istvàn UniversityHungary Adnan Kassar School of Business Lebanese American UniversityBeirutLebanon Indian Institute of Management Bodh Gaya Bodh GayaBiharIndia

In the context of increasingly tight constraints on global resources and environment,accelerating the conservation and recycling of fossil fuels and other mineral resources have become significant *** promoting the transformation of energy development mode,and making efficient use of coal,oil,natural gas,iron ore,potassium salts,phosphate,sulfur and other mineral resources have become important issues in energy planning and energy *** the framework of Sustainable Development Goals,it is urgent and critical to investigate the relationship between geological resource saving,recycling and modern energy systems,which is an important step to establish a complete system of efficient use of natural resources.

关键词： energy transition recycling

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Design and Implementation of a State-feedback Controller Using LQR Technique

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Computers, Materials & Continua 2022年第11期73卷 2897-2911页

作者： Aamir shahzad Shadi Munshi Sufyan Azam Muhammad Nasir Khan Mechanical Engineering Department The University of LahoreLahorePakistan Mechanical Engineering Department Umm Al-Qura UniversityMakkahSaudi Arabia Electrical Engineering Department The University of LahoreLahorePakistan

The main objective of this research is to design a state-feedback controller for the rotary inverted pendulum module utilizing the linear quadratic regulator(LQR)*** controller maintains the pendulum in the inverted(upright)position and is robust enough to reject external disturbance to maintain its *** research work involves three major contributions:mathematical modeling,simulation,and real-time *** design a controller,mathematical modeling has been done by employing the NewtonEuler,Lagrange *** resulting model was nonlinear so linearization was required,which has been done around a working *** the estimation of the controller parameters,MATLAB LQR function has been *** has been performed for the designed controller and it also has been implemented and tested over the real inverted *** the results,it is vivid that the designed controller keeps the inverted pendulum in an upright position and rejects the disturbances and falling under gravitational force by adjusting the rotation of the horizontal link.

关键词： Mathematical modeling linearization linear quadratic regulator(LQR) nonlinear system rotary inverted pendulum

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Intelligent cluster routing scheme for flying ad hoc networks

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Science China(Information Sciences) 2021年第8期64卷 76-89页

作者： Ali KHAN Somaiya KHAN Athar shahzad FAZAL Zhongshan ZHANG Adnan Omer ABUASSBA School of Computer and Communication Engineering University of Science and Technology Beijing School of Information and Electronics Beijing Institute of Technology School of Information Technology Arab Open University

Flying ad hoc networks are used for many critical tasks. The network formation for routing data becomes difficult because of the mobility of unmanned aerial vehicles(UAVs). To solve the communication issue, we propose an intelligent cluster routing scheme for flying ad hoc networks(CRSF). Cluster head(CH)selection in our proposed methodology is based on fitness, which is determined by the position and UAVs’ residual energy. For the efficient management of UAV swarm, a cluster management mechanism is also proposed, inspired by moth flame optimization. In CRSF, for stable cluster maintenance, a CH re-selection mechanism is proposed in detail, which helps maintain the cluster for effective topology management. A routing mechanism for UAV communication is proposed for CRSF. The route selection for transmission of information is performed using the route identification function based on the Euclidean distance and residual energy. The performance of the proposed CRSF is evaluated and compared with the existing routing algorithms.

关键词： self-organized unmanned aerial vehicles UAV clustering routing FANETs

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Changes in Nutrient-Homeostasis and Reserves Metabolism During Rice Seed Priming:Consequences for Seedling Emergence and Growth

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Agricultural Sciences in China 2010年第2期9卷 191-198页

作者： Muhammad Farooq shahzad M A Basra Abdul Wahid Nazir Ahmad Department of Agronomy University of AgricultureFaisalabad Department of Crop Physiology University of AgricultureFaisalabad Department of Botany University of AgricultureFaisalabad

In this study influence of different seed priming treatments on the nutrient-homeostasis and reserve metabolism during seedling emergence and growth of rice were determined. Seed priming treatments included pre-germination, hydropriming for 48 h, osmohardening with KCl and CaCl2, ascorbate priming and hardening. All treatments shortened the emergence time and enhanced the energy and index of seedling emergence. Seedlings from primed seeds had greater length, number of roots and fresh and dry mass than control. Among the treatments, CaCl2, ascorbate and KCl proved better in enhancing emergence and seedling growth. Seed priming changed the pattern of N and Ca^2＋ homeostasis both of the seeds and seedlings, which were associated to enhancing s-amylase activity and reducing sugars content. Positive correlations of seedling attributes with nutrient content suggested that as a result of seed priming, most of N and Ca^2＋ were partitioned to embryo, which enhanced seedling emergence and subsequent growth of rice seedlings.

关键词： rice α-amylase activity nutrient homeostasis seedling emergence seedling vigor

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