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A Novel Approximate Message Passing Detection for Massive MIMO 5G System
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作者 Nidhi Gour Rajneesh Pareek +5 位作者 karthikeyan rajagopal Himanshu Sharma Mrim M.Alnfiai Mohammed A.AlZain Mehedi Masud Arun Kumar 《Computer Systems Science & Engineering》 SCIE EI 2023年第6期2827-2835,共9页
Massive-Multiple Inputs and Multiple Outputs(M-MIMO)is considered as one of the standard techniques in improving the performance of Fifth Generation(5G)radio.5G signal detection with low propagation delay and high thr... Massive-Multiple Inputs and Multiple Outputs(M-MIMO)is considered as one of the standard techniques in improving the performance of Fifth Generation(5G)radio.5G signal detection with low propagation delay and high throughput with minimum computational intricacy are some of the serious concerns in the deployment of 5G.The evaluation of 5G promises a high quality of service(QoS),a high data rate,low latency,and spectral efficiency,ensuring several applications that will improve the services in every sector.The existing detection techniques cannot be utilised in 5G and beyond 5G due to the high complexity issues in their implementation.In the proposed article,the Approximation Message Passing(AMP)is implemented and compared with the existing Minimum Mean Square Error(MMSE)and Message Passing Detector(MPD)algorithms.The outcomes of the work show that the performance of Bit Error Rate(BER)is improved with minimal complexity. 展开更多
关键词 AMP MMSE MPD 5G
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Peak-Average-Power Ratio Techniques for 5G Waveforms Using D-SLM and D-PTS
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作者 Himanshu Sharma karthikeyan rajagopal +7 位作者 G.Gugapriya Rajneesh Pareek Arun Kumar HayaMesfer Alshahrani Mohamed K.Nour Hany Mahgoub Mohamed Mousa Anwer Mustafa Hilal 《Computer Systems Science & Engineering》 SCIE EI 2023年第5期1199-1210,共12页
Multicarrier Waveform(MCW)has several advantages and plays a very important role in cellular systems.Fifth generation(5G)MCW such as Non-Orthogonal Multiple Access(NOMA)and Filter Bank Multicarrier(FBMC)are thought to... Multicarrier Waveform(MCW)has several advantages and plays a very important role in cellular systems.Fifth generation(5G)MCW such as Non-Orthogonal Multiple Access(NOMA)and Filter Bank Multicarrier(FBMC)are thought to be important in 5G implementation.High Peak to Average Power Ratio(PAPR)is seen as a serious concern in MCW since it reduces the efficiency of amplifier use in the user devices.The paper presents a novel Divergence Selective Mapping(DSLM)and Divergence Partial Transmission Sequence(D-PTS)for 5G waveforms.It is seen that the proposed D-SLM and PTS lower PAPR with low computational complexity.The work highlighted a combination of multi-data block partial transmit schemes along with tone reservation.In this,an overlapping factor is used to determine the number of data blocks for every group.Here,considering only those data blocks that have minimum signal power,the use of DSLM and DPTS are required to eliminate the segment’s peaks.Simulation results reveal that the suggested hybrid technique proves to be better than the conventional PTS scheme.Furthermore,the power saving performance of FBMC and NOMA is compared with the Orthogonal Frequency Division Multiplexing(OFDM)waveform. 展开更多
关键词 5G PAPR D-SLM D-PTS
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A new nonlinear oscillator with infinite number of coexisting hidden and self-excited attractors 被引量:2
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作者 唐妍霞 Abdul Jalil M Khalaf +3 位作者 karthikeyan rajagopal Viet-Thanh Pham Sajad Jafari 田野 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第4期208-213,共6页
In this paper,we introduce a new two-dimensional nonlinear oscillator with an infinite number of coexisting limit cycles.These limit cycles form a layer-by-layer structure which is very unusual.Forty percent of these ... In this paper,we introduce a new two-dimensional nonlinear oscillator with an infinite number of coexisting limit cycles.These limit cycles form a layer-by-layer structure which is very unusual.Forty percent of these limit cycles are self-excited attractors while sixty percent of them are hidden attractors.Changing this new system to its forced version,we introduce a new chaotic system with an infinite number of coexisting strange attractors.We implement this system through field programmable gate arrays. 展开更多
关键词 chaotic oscillators MULTISTABILITY hidden attractors
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Reinforcement Learning Based Controller Synthesis for Flexible Aircraft Wings 被引量:4
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作者 Manoj Kumar karthikeyan rajagopal +1 位作者 Sivasubramanya Nadar Balakrishnan Nhan T.Nguyen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2014年第4期435-448,共14页
Aeroelastic study of flight vehicles has been a subject of great interest and research in the last several years. Aileron reversal and flutter related problems are due in part to the elasticity of a typical airplane. ... Aeroelastic study of flight vehicles has been a subject of great interest and research in the last several years. Aileron reversal and flutter related problems are due in part to the elasticity of a typical airplane. Structural dynamics of an aircraft wing due to its aeroelastic nature are characterized by partial differential equations. Controller design for these systems is very complex as compared to lumped parameter systems defined by ordinary differential equations. In this paper, a stabilizing statefeedback controller design approach is presented for the heave dynamics of a wing-fuselage model. In this study, a continuous actuator in the spatial domain is assumed. A control methodology is developed by combining the technique of “proper orthogonal decomposition” and approximate dynamic programming. The proper orthogonal decomposition technique is used to obtain a low-order nonlinear lumped parameter model of the infinite dimensional system. Then a near optimal controller is designed using the single-network-adaptive-critic technique. Furthermore,to add robustness to the nominal single-network-adaptive-critic controller against matched uncertainties, an identifier based adaptive controller is proposed. Simulation results demonstrate the effectiveness of the single-network-adaptive-critic controller augmented with adaptive controller for infinite dimensional systems. 展开更多
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Controlling chaos and supressing chimeras in a fractional-order discrete phase-locked loop using impulse control
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作者 karthikeyan rajagopal Anitha karthikeyan Balamurali Ramakrishnan 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第12期63-73,共11页
A fractional-order difference equation model of a third-order discrete phase-locked loop(FODPLL) is discussed and the dynamical behavior of the model is demonstrated using bifurcation plots and a basin of attraction. ... A fractional-order difference equation model of a third-order discrete phase-locked loop(FODPLL) is discussed and the dynamical behavior of the model is demonstrated using bifurcation plots and a basin of attraction. We show a narrow region of loop gain where the FODPLL exhibits quasi-periodic oscillations, which were not identified in the integer-order model. We propose a simple impulse control algorithm to suppress chaos and discuss the effect of the control step. A network of FODPLL oscillators is constructed and investigated for synchronization behavior. We show the existence of chimera states while transiting from an asynchronous to a synchronous state. The same impulse control method is applied to a lattice array of FODPLL, and the chimera states are then synchronized using the impulse control algorithm. We show that the lower control steps can achieve better control over the higher control steps. 展开更多
关键词 discrete Josephson junction fractional order chaos impulse control CHIMERA
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A Novel Peak-to-Average Power Ratio Reduction for 5G Advanced Waveforms
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作者 Rajneesh Pareek karthikeyan rajagopal +6 位作者 Himanshu Sharma Nidhi Gour Arun Kumar Sami Althahabi Haya Mesfer Alshahrani Mohamed Mousa Manar Ahmed Hamza 《Computers, Materials & Continua》 SCIE EI 2022年第10期1637-1648,共12页
Multi and single carrier waveforms are utilized in cellular systems for high-speed data transmission.In The Fifth Generation(5G)system,several waveform techniques based on multi carrier waveforms are proposed.However,... Multi and single carrier waveforms are utilized in cellular systems for high-speed data transmission.In The Fifth Generation(5G)system,several waveform techniques based on multi carrier waveforms are proposed.However,the Peak to Average Power Ratio(PAPR)is seen as one of the significant concerns in advanced waveforms as it degrades the efficiency of the framework.The proposed article documents the study,progress,and implementation of PAPR reduction algorithms for the 5G radio framework.We compare the PAPR algorithm performance for advanced and conventional waveforms.The simulation results reveal that the advanced Partial Transmission Sequence(PTS)and Selective Mapping(SLM)methods enhanced the throughput and gain of the 5G waveforms.Furthermore,we have also analyzed the performance of Orthogonal Time Frequency Space Modulation(OTFSM)based on a single carrier system and found that PAPR is significantly low and is best suited to fading environments.It is seen that the conventional algorithms lower the PAPR but increase the complexity.The proposed PTS and SLM have shown good performance with low computational complexity. 展开更多
关键词 PAPR 5G OFDM NOMA OTFSM PTS SLM
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A novel multi-stable sinusoidal chaotic map with spectacular behaviors
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作者 Ahmed M Ali Ali Sridevi Sriram +3 位作者 Hayder Natiq Atefeh Ahmadi karthikeyan rajagopal Sajad Jafari 《Communications in Theoretical Physics》 SCIE CAS CSCD 2023年第11期3-14,共12页
Chaotic behavior can be observed in continuous and discrete-time systems.This behavior can appear in one-dimensional nonlinear maps;however,having at least three state variables in flows is necessary.Due to the lower ... Chaotic behavior can be observed in continuous and discrete-time systems.This behavior can appear in one-dimensional nonlinear maps;however,having at least three state variables in flows is necessary.Due to the lower mathematical complexity and computational cost of maps,lots of research has been conducted based on them.This paper aims to present a novel one-dimensional trigonometric chaotic map that is multi-stable and can act attractively.The proposed chaotic map is first analyzed using a single sinusoidal function;then,its abilities are expanded to a map with a combination of two sinusoidal functions.The stability conditions of both maps are investigated,and their different behaviors are validated through time series,state space,and cobweb diagrams.Eventually,the influence of parameter variations on the maps’outputs is examined by one-dimensional and two-dimensional bifurcation diagrams and Lyapunov exponent spectra.Besides,the diversity of outputs with varying initial conditions reveals this map’s multi-stability.The newly designed chaotic map can be employed in encryption applications. 展开更多
关键词 chaotic map discrete chaos sinusoidal map multi-stability dynamical analysis
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Dynamics of a neuron exposed to integer-and fractional-order discontinuous external magnetic flux 被引量:2
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作者 karthikeyan rajagopal Fahimeh NAZARIMEHR +3 位作者 Anitha karthikeyan Ahmed ALSAEDI Tasawar HAYAT Viet-Thanh PHAM 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2019年第4期584-590,共7页
We propose a modified Fitzhugh-Nagumo neuron(MFNN) model. Based on this model, an integerorder MFNN system(case A) and a fractional-order MFNN system(case B) were investigated. In the presence of electromagnetic induc... We propose a modified Fitzhugh-Nagumo neuron(MFNN) model. Based on this model, an integerorder MFNN system(case A) and a fractional-order MFNN system(case B) were investigated. In the presence of electromagnetic induction and radiation, memductance and induction can show a variety of distributions. Fractionalorder magnetic flux can then be considered. Indeed, a fractional-order setting can be acceptable for non-uniform diffusion. In the case of an MFNN system with integer-order discontinuous magnetic flux, the system has chaotic and non-chaotic attractors. Dynamical analysis of the system shows the birth and death of period doubling, which is a sign of antimonotonicity. Such a behavior has not been studied previously in the dynamics of neurons. In an MFNN system with fractional-order discontinuous magnetic flux, different attractors such as chaotic and periodic attractors can be observed. However, there is no sign of antimonotonicity. 展开更多
关键词 Fitzhugh-Nagumo Chaos FRACTIONAL order Magnetic flux
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Dynamic analysis,FPGA implementation,and cryptographic application of an autonomous 5D chaotic system with offset boosting 被引量:2
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作者 Sifeu TAKOUGANG KINGNI karthikeyan rajagopal +2 位作者 Serdar CICEK Ashokkumar SRINIVASAN Anitha karthikeyan 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2020年第6期950-961,共12页
An autonomous five-dimensional(5D)system with offset boosting is constructed by modifying the well-known three-dimensional autonomous Liu and Chen system.Equilibrium points of the proposed autonomous 5D system are fou... An autonomous five-dimensional(5D)system with offset boosting is constructed by modifying the well-known three-dimensional autonomous Liu and Chen system.Equilibrium points of the proposed autonomous 5D system are found and its stability is analyzed.The proposed system includes Hopf bifurcation,periodic attractors,quasi-periodic attractors,a one-scroll chaotic attractor,a double-scroll chaotic attractor,coexisting attractors,the bistability phenomenon,offset boosting with partial amplitude control,reverse period-doubling,and an intermittency route to chaos.Using a field programmable gate array(FPGA),the proposed autonomous 5D system is implemented and the phase portraits are presented to check the numerical simulation results.The chaotic attractors and coexistence of the attractors generated by the FPGA implementation of the proposed system have good qualitative agreement with those found during the numerical simulation.Finally,a sound data encryption and communication system based on the proposed autonomous 5D chaotic system is designed and illustrated through a numerical example. 展开更多
关键词 Chaotic system Hopf bifurcation Coexistence of attractors Offset boosting FPGA implementation Sound encryption
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上位效应对遗传算法可靠性的影响(英文)
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作者 Sajad JAFARI Tomasz KAPITANIAK +2 位作者 karthikeyan rajagopal Viet-Thanh PHAM Fawaz E.ALSAADI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2019年第2期109-116,共8页
目的:探讨遗传算法的局限性和实用性,并分析基于相互作用产生的上位效应对遗传算法可靠性的影响。创新点:1.指出遗传算法缺陷的根源;2.基于测试样本函数定义目标函数,以判断遗传算法的适用性。方法:1.基于非上位效应函数(表1)和上位效... 目的:探讨遗传算法的局限性和实用性,并分析基于相互作用产生的上位效应对遗传算法可靠性的影响。创新点:1.指出遗传算法缺陷的根源;2.基于测试样本函数定义目标函数,以判断遗传算法的适用性。方法:1.基于非上位效应函数(表1)和上位效应函数(表2),以及非上位效应函数F4和上位效应函数F6的结构图来验证遗传算法可靠性;2.通过计算样本函数(公式(1))和遗传算法流程(图3)表达遗传算法的工作原理。3.利用克洛弗函数(公式(2))和计算不同结构角下的函数分布(图4),进一步判断匹配度(表3)和计算效率(表4);定义新的目标函数(公式(9))和一组新的变量(公式(10))来实现变量相关性解离。结论:1.对当前遗传算法存在的不足给出了独到见解,并认为正定性的假设并非可以保证遗传算法实际的有效性和优化性。2.定义成本代价函数用以判断遗传算法可靠性,并分别考虑上位性和非上位性效应两种情形。当成本代价函数在非上位性效应下时,遗传算法是有效的;否则,可以把N维函数降级为N个一维函数,从而采用更简单的算法来判断。基于一些通用的基准,进一步设计三类样本函数来证实以上判断,且这些样本函数适合于上位性效应情形和非上位效应情形。3.遗传算法的瓶颈在于主算子和相干匹配性;可以通过破坏某些结构来实现变量关系的解离,从而抑制相干匹配性对遗传算法的影响。希望相关读者在处理实际优化问题时能验证作者关于上位效应的定性结论,并给出更可靠的方法来表征这种效应。 展开更多
关键词 上位性效应 遗传算法 相干匹配性 叠加性 优化 成本代价函数
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Chimera state in a network of nonlocally coupled impact oscillators
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作者 Jerzy WOJEWODA karthikeyan rajagopal +3 位作者 Viet-Thanh PHAM Fatemeh PARASTESH Tomasz KAPITANIAK Sajad JAFARI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2021年第3期235-244,共10页
Chimera state is a peculiar spatiotemporal pattern,wherein the coherence and incoherence coexist in the network of coupled identical oscillators.In this paper,we study the chimera states in a network of impact oscilla... Chimera state is a peculiar spatiotemporal pattern,wherein the coherence and incoherence coexist in the network of coupled identical oscillators.In this paper,we study the chimera states in a network of impact oscillators with nonlocal coupling.We investigate the effects of the coupling strength and the coupling range on the network behavior.The results reveal the emergence of the chimera state for significantly small values of coupling strength,and higher coupling strength values lead to unbounded motions in the oscillators.We also study the network in the case of excitation failure.We observe that the coupling helps in the maintenance of an oscillatory motion with a lower amplitude in the failed oscillator. 展开更多
关键词 Mechanical oscillators Impact oscillator Coupled network Nonlocal coupling Chimera state
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Observation of chimera patterns in a network of symmetric chaotic finance systems
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作者 Biqun Chen karthikeyan rajagopal +3 位作者 Fatemeh Parastesh Hamed Azarnoush Sajad Jafari Iqtadar Hussain 《Communications in Theoretical Physics》 SCIE CAS CSCD 2020年第10期19-28,共10页
The economic and financial systems consist of many nonlinear factors that make them behave as the complex systems.Recently many chaotic finance systems have been proposed to study the complex dynamics of finance as a ... The economic and financial systems consist of many nonlinear factors that make them behave as the complex systems.Recently many chaotic finance systems have been proposed to study the complex dynamics of finance as a noticeable problem in economics.In fact,the intricate structure between financial institutions can be obtained by using a network of financial systems.Therefore,in this paper,we consider a ring network of coupled symmetric chaotic finance systems,and investigate its behavior by varying the coupling parameters.The results show that the coupling strength and range have significant effects on the behavior of the coupled systems,and various patterns such as the chimera and multi-chimera states are observed.Furthermore,changing the parameters'values,remarkably influences on the oscillators attractors.When several synchronous clusters are formed,the attractors of the synchronized oscillators are symmetric,but different from the single oscillator attractor. 展开更多
关键词 nance system symmetric attractors chimera state synchronization transitions nonlocally coupled network
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Chaotic dynamics of a fractional order glucose-insulin regulatory system
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作者 karthikeyan rajagopal Atiyeh BAYANI +2 位作者 Sajad JAFARI Anitha karthikeyan Iqtadar HUSSAIN 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2020年第7期1108-1118,共11页
The fractional order model of a glucose-insulin regulatory system is derived and presented. It has been extensively proved in the literature that fractional order analysis of complex systems can reveal interesting and... The fractional order model of a glucose-insulin regulatory system is derived and presented. It has been extensively proved in the literature that fractional order analysis of complex systems can reveal interesting and unexplored features of the system. In our investigations we have revealed that the glucose-insulin regulatory system shows multistability and antimonotonicity in its fractional order form. To show the effectiveness of fractional order analysis, all numerical investigations like stability of the equilibrium points, Lyapunov exponents, and bifurcation plots are derived. Various biological disorders caused by an unregulated glucose-insulin system are studied in detail. This may help better understand the regulatory system. 展开更多
关键词 Diabetes mellitus Chaos BIFURCATION MULTISTABILITY Antimonotonicity
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