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Nonlinear Sliding manifold for High Performance Lateral Guidance of UAV 36

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Nonlinear Sliding Manifold for High Performance Lateral Guid...

第36届中国控制会议

作者： Syed Ussama Ali Raza Samar m.zamurad shah Center of Excellence in Science and Applied Technologies （CESAT）

ISBN: (纸本)9781538629185

This paper presents a novel guidance algorithm for UAVs to follow a 2-D ground track by controlling the lateral cross track deviations. The guidance framework based on sliding mode theory is presented to solve the two dimensional path-following problem. To control the lateral track error of the vehicle during flight, the guidance algorithm generates reference bank angle commands for the vehicle control system i.e., by executing roll maneuvers. Novel nonlinear high performance sliding surface is proposed to reduce the lateral cross track error efficiently. Subsequently, 1storder sliding mode guidance logic is then devised using the proposed manifold for generating reference bank angle commands. Stability of the proposed nonlinear manifold is proved using Lyapunov *** boundedness is proved to avoid saturation of control signals. Effectiveness of the proposed algorithm is shown via simulation results for a research scaled YAK-54 UAV. Different scenarios（consisting of both small and large lateral errors）in simulation validates the proposed guidance framework and illustrates the effectiveness of the algorithm.

关键词： manifolds Unmanned aerial vehicles Stability analysis Sliding mode control Kinematics Switches

Adaptive Sliding mode Roll Control of a Canard-Controlled missile

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Adaptive Sliding Mode Roll Control of a Canard-Controlled Mi...

2010 Chinese Control and Decision Conference

作者： m.zamurad shah Raza Samar A.I.Bhatti mohammad Ali Jinnah University IslamabadPakistan

This work is meant to design a roll controller for a short range missile with a free-spinning tail using the sliding mode control *** canards located near the nose of the missile provide aerodynamic ***/yaw stability is achieved through four rotating fins located at the tail of the *** of the missile dictates the whole trajectory in the atmosphere where dynamic pressure varies between 0 and 7 *** the missile can be fired at different launch angles,which implies that the profile of dynamic pressure is not *** strategy strongly depends on dynamic pressure in the case of canard-controlled *** the case of varying dynamic pressure,design of a robust roll controller that can keep roll angle near zero is a challenging *** this paper,a roll controller is designed for a canard-controlled short range missile using sliding mode control *** is done in some control parameters to cater the variation in dynamic pressure and different launch *** robustness of the roll controller is tested in the presence of aerodynamic and other *** is established that the proposed roll controller is capable of rejecting aerodynamic and other disturbances and keep the roll angle close to zero.

关键词： missile sliding mode control adaptive control autopilot aerodynamics canards.

Robust Nonlinear Control Design For Scaled Yak-54 Unmanned Aerial Vehicle

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Robust Nonlinear Control Design For Scaled Yak-54 Unmanned A...

第26届中国控制与决策会议

作者： Ussama Ali m.zamurad shah Aamer Iqbal Bhatti Raza Samar Faculty of Electronic Engineering Mohammed Ali Jinnah University

In this work, the authors consider the applications of sliding mode controllers to the longitudinal flight dynamics of the benchmark system of scaled Yak-54 Unmanned Aerial Vehicle for executing maneuvers over full flight *** of unmanned aerial vehicle involves the problem of incomplete measurements, modeling uncertainties and external disturbances. Sliding mode control provides good precision and robustness to the aforementioned factors. First order sliding mode controller are designed but they provide chattering at the control input thus a non linear second order super twisting controller is used to provide chattering free control with improved performance for the robust stabilization of pitch angle and control of its altitude. The simulation results indicate good tracking and regulation control of the vehicle.

关键词： Sliding mode Control SmC Higher Order Sliding mode Control HOSm Strong Reachability Condition SRC

macular microvascular and structural changes on optical coherence tomography angiography in atypical optic neuritis

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World Journal of methodology 2025年第1期15卷 88-94页

作者： Chinmay mahatme madhurima Kaushik Veerappan Rathinasabapathy Saravanan Karthik Kumar Virna m shah Department of General Ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia Department of Neuro-ophthalmology Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia Department of Vitreoretina Aravind Eye HospitalCoimbatore 641014Tamil NāduIndia

BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NmOSD)or myelin oligodendrocyte glycoprotein antibody disease(mOGAD),has a very similar presentation but different prognostic implications and longterm management *** and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated *** the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural *** To study the macular microvascular and structural changes on OCTA in atypical optic *** This observational cross-sectional study involved 8 NmOSD and 17 mOGAD patients,diagnosed serologically,as well as 10 healthy *** vascular density(mVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using *** There was a significant reduction in mVD in NmOSD and mOGAD affected as well as unaffected eyes when compared with healthy *** and mOGAD affected eyes had significant GCIPL thinning compared with healthy *** unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to mOGAD unaffected *** comparing NmOSD with mOGAD,there was no significant difference in terms of mVD or GCIPL in the affected or unaffected *** Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NmOSD and mOGAD cases.

关键词： Optical coherence tomography angiography Atypical optic neuritis macular microvascular changes Neuromyelitis optica spectrum disorders myelin oligodendrocyte glycoprotein antibody disorder

Alternative Strategy for Development of Dielectric Calcium Copper Titanate‑Based Electrolytes for Low‑Temperature Solid Oxide Fuel Cells

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Nano-micro Letters 2025年第1期17卷 310-332页

作者： Sajid Rauf muhammad Bilal Hanif Zuhra Tayyab matej Veis mAKYousaf shah Naveed mushtaq Dmitry medvedev Yibin Tian Chen Xia martin motola Bin Zhu College of mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060People’s Republic of China Department of Inorganic Chemistry Faculty of Natural SciencesComenius University BratislavaIlkovicova684215 BratislavaSlovakia Energy Storage Joint Research Center School of Energy and EnvironmentSoutheast UniversityNanjing 210096People’s Republic of China Hydrogen Energy Laboratory Ural Federal University620002 EkaterinburgRussia Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes Institute of High Temperature Electrochemistry620066 EkaterinburgRussia School of microelectronics Hubei UniversityWuhan 430062People’s Republic of China

The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of *** has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of *** this context,for the first time,a dielectric material,CaCu_(3)Ti_(4)O_(12)(CCTO)is designed for LT-SOFCs electrolyte application in this *** individual CCTO and its heterostructure materials with a p-type Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ)(NCAL)semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550℃.The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm^(-2) and an open-circuit voltage(OCV)of 0.95 V at 550℃,while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm^(-2) along with a higher OCV over 1.0 V,which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting *** is found that these promising outcomes are due to the interplay of the dielectric material,its structure,and overall properties that led to improve electrochemical mechanism in CCTO–***,density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–*** study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.

关键词： LT-SOFCs Dielectric CaCu_(3)Ti_(4)O_(12) Semiconductor Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ) Ionic conductivity Heterostructure electrolyte

Enhancing secrecy rates in a wiretap channel

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Digital Communications and Networks 2020年第1期6卷 129-135页

作者： shahid m.shah Vinod Sharma Department of ECE Indian Institute of ScienceBangalore560012India

Reliable communication imposes an upper limit on the achievable rate,namely the Shannon ***'s wiretap coding ensures a security constraint and reliability,but results in a decrease of achievable *** mitigate the loss in secrecy rate,we propose a coding scheme in which we use sufficiently old messages as key and prove that multiple messages are secure with respect to all the information possessed by the *** also show that we can achieve security in the strong ***,we study a fading wiretap channel with full channel state information of the eavesdropper's channel and use our coding/decoding scheme to achieve a secrecy capacity close to the Shannon capacity of the main channel(in the ergodic sense).Finally,we study a case where the transmitter does not have instantaneous information of the channel state of the eavesdropper,but only its distribution.

关键词： Physical layer security Rate loss Secret key Wiretap channel Secrecy capacity

PREPARATION AND CHARACTERIZATION OF SCHIFF BASE POLYmERS DERIVED FROm 4,4'-mETHYLENEBIS(CINNAmALDEHYDE)

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Chinese Journal of Polymer Science 2007年第4期25卷 399-407页

作者： m.Y. Khuhawar A. shah m.A. mughal Dr. m.A. Kazi Institute of Chemistry University of SindhJamshoroSindhPakistan

New Schiff base polymers poly[4,4＇-methylenebis（cinnamaldehyde）ethylenediimine] （PmBCen）, poly[4,4＇- methylenebis（cinnamaldehyde）1,2-propylenediimine] （PmBCPn）, poly[4,4＇-methylenebis（cinnamaldehyde）1,3-propylenediimine] （PmBCPR）, poly[4,4＇-methylenebis（cinnamaldehyde） 1,2-phenylenediimine] （PmBCPh）, poly[4,4＇-methylenebis（cinnamaldehyde）meso-stilbenediimine] （PmBCS）, poly[4,4＇-methylenebis（cinnamaldehyde）urea] （PmBCUR）, poly[4,4＇- methylenebis（cinnamaldehyde）semicarbazone] （PmBCSc）, poly[4,4＇-methylenebis（cinnamaldehyde）thiosemicarbazone] （PmBCTSc） and poly[4,4＇-methylenebis（cinnamaldehyde）hydrazone] （PmBCH） were formed by polycondensation of 4,4＇- methylenebis（cinnamaldehyde） with ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,2-phenylenediamine, meso-stilbenediamine, urea, semicarbazide, thiosemicarbazide and hydrazine, respectively. The dialdehyde and polymers have been characterized through elemental micro-analysis, IR, UV-Vis and ^1H-NmR spectroscopic techniques. Thermoanalytical studies and viscous flow of dilute solutions of dialdehyde and its polymers have been examined and compared.

关键词： Schiff base polymers Synthesis Characterization Infrared spectroscopy Ultraviolet-visible spectroscopy Nuclear magnetic resonance Thermogravimetric analysis Differential thermal analysis.

Structural,Dielectric and Complex Impedance Spectroscopy Studies of Lead Free Ca_(0.5+x)Nd_(0.5-x)(Ti_(0.5)Fe_(0.5))O_3

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Journal of materials Science & Technology 2013年第4期29卷 323-329页

作者： m.R.shah A.K.m.Akther Hossain Department of Physics University of PrimeasiaBananiDhaka 1213Bangladesh Department of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

Structural and various electrical properties of polycrystalline Ca0.5＋xNd0,5-x（Ti0.5Fe0.5）O3, prepared by standard solid state reaction technique, were studied. Formation of single phase orthorhombic structure of the compositions was confirmed by X-ray diffraction study. The composition dependence of lattice parameters, density and microstructural study show that they vary significantly with Ca content. The dielectric measurements were carried out at room temperature as function of frequency and composition. The experimental results reveal that the dielectric constant （ε′） increases with increasing Ca content. Similar behavior is observed for the dielectric loss （tanδ） and ac conductivity （σac）. In complex impedance analysis it is observed that the real part （Z′） vs imaginary part （Z″） graph exhibits a tendency of formation of a single semicircular arc for each composition of samples. Different parameters were determined by fitting the experimental data in Cole-Cole empirical formula. A dominance of grain boundary resistance （Rgb） is observed. The Rgb decreases with increasing Ca content. The high ε′ observed in present samples are suitable for fabrication of devices.

关键词： Crystal structure Dielectric properties Lead free Perovskite Solid state reaction

Robust Level Flight Control Design For Scaled Yak-54 Unmanned Aerial Vehicle using Single Sliding Surface.

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Robust Level Flight Control Design For Scaled Yak-54 Unmanne...

第24届中国控制与决策会议

作者： Ussama Ali m. zamurad shah Raza Samar Aamer Iqbal Bhatti Faculty of Electronic Engineering Mohammed Ali Jinnah University

This paper deals with devising robust nonlinear control strategy for benchmark system of scaled Yak-54 Unmanned Aerial Vehicle. Authors considered the applications of sliding mode controllers to the longitudinal flight dynamics of the Yak-54 UAV for executing maneuvers over full flight envelope. Unlike the classical technique of the two sliding surfaces for the two loops a single surface is selected for the level flight. Control of unmanned aerial vehicle involves the problem of incomplete measurements, modeling uncertainties and external disturbances which makes flight dynamic analysis and control system design difficult. We present an innovative robust control strategy based on powerful tools provided by the theory of sliding mode control algorithms. First order sliding mode controller are designed but they provide chattering at the control input thus a non linear second order super twisting controller is used to provide chattering free control with improved robust stabilization.

关键词： Sliding mode Control SmC Higher Order Sliding mode Control HOSm Strong Reachability Condition SRC