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8th EAI International Conference on Smart Grid and Innovative Frontiers in Telecommunications, SmartGIFT 2024

作者： Khan, Hamood ur Rehman Khan, Farhan Sir Syed Center for Advanced Studies in Engineering Islamabad Pakistan Electrical and Computer Engineering Program Habib University Karachi Pakistan

ISBN: (纸本)9783031788055

Current and future trends in seismic acquisition point towards higher geophone densities (forecasted to be 1M nodes per survey). The geophones’ high operating precision and a sampling rate of a few milliseconds leads to a huge aggregate data rate in the geophone array. To handle this large data rate a hierarchy of multiplexed lines (including fiber optic cables) are used, resulting in substantial deployment costs. This work considers wireless geophone networks to mitigate these costs. Because of limited bandwidth of the wireless medium, compression of acquired data is needed. We assess lossy source coding (signal compression) performance using a rate-distortion tradeoff based on a physical model of the earth. The distortion criterion used is mean squared error. The earth’s physical model considered here consists of a randomly layered subsurface structure where the acoustic impedance of the earth varies as a homogeneous spatial random process. The rate distortion performance is assessed in terms of the parameters of this physical model e.g., the speed of sound underground and correlation length of acoustic impedance process. In comparison with previous work, this paper derives a closed form expression for the autocorrelation function for the reflection process for the 3D subsurface volume. We also show from the resulting rate-distortion curves that the compression performance improves both as the coding bock length increases and as the correlation length of the medium properties increases. The rate-distortion surface as a function of normalized MSE and sound of speed underground is also computed and validated through extensive simulations. © ICST Institute for Computer Sciences, Social Informatics and Telecommunications engineering 2025.

关键词： Signal distortion

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Pilot Spacing Adaptation in OFDM for a Flexible Next Generation Waveform 91

Pilot Spacing Adaptation in OFDM for a Flexible Next Generat...

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91st IEEE Vehicular Technology Conference, VTC Spring 2020

作者： Khan, Zaid Nisar, M. Danish Center for Advanced Research in Engineering Islamabad Pakistan Sir Syed Case Institute of Technology Islamabad Pakistan

ISBN: (纸本)9781728152073

With an ever increasing demand for data rates over limited bandwidth, spectral efficiency (SE) has become one of the main areas of interest in future wireless communication. In this paper, we propose an adaptive pilot spacing scheme for Pilot Symbol Assisted Orthogonal Frequency Division Multiplexing (PSA-OFDM) systems in order to enhance SE while not compromising channel estimate performance. In contrast to traditional approaches, the technique takes into account the frequency selectivity of the user channel and adjusts pilot spacing in frequency domain accordingly. We utilize the existing FFT module at the receiver while exploiting the Nyquist theorem in Fourier domain. For proof of concept, we simulated a PSA-OFDM system under varying degrees of channel frequency selectivity and employed the proposed pilot spacing adaptation technique. The proposed method is compared with block-type pilot transmission in terms of channel estimation Mean Square Error and Bit Error Rate in Rayleigh fading channels. It is shown that a spectral gain of up to 1.75 dB can be achieved by adopting the proposed scheme. © 2020 IEEE.

关键词： Spectrum efficiency

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'3D' - A Doppler, directivity and distance based architecture for selecting stable routing links in VANETs

'3D' - A Doppler, directivity and distance based architectur...

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2009 2nd International Conference on Computer, Control and Communication, IC4 2009

作者： Rasheed, Asim Ajmal, Sana Computer Engineering Department Centre for Advanced Studies in Engineering Sir Syed Memorial Building 19-Ataturk Avenue G-5/1 Islamabad Pakistan

ISBN: (纸本)9781424433148

Vehicular networks show very fast topology changes and frequent network fragmentation. Selection of stable routing links in multi-hop communication requires the speed and direction of movement of the neighbouring vehicles to be taken into account. This paper proposes'3D': a Doppler, Distance and Directivity based routing protocol architecture, making decisions on considerations of relative vehicular speed and direction. From amongst the stable links, to select those having longest lifetime, distance between the nodes and their relative placement is considered.

关键词： Network architecture

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Development of stability-preserving time-limited model reduction framework for 2-D and 1-D models with error bound

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Control Theory and Technology 2022年第3期20卷 371-381页

作者： Muhammad Imran syeda Hira Ambreen syed Nooh Hamdani Muhammad Imran Muhammad Ejaz Naveed Maria Siddiqui Department of Electrical Engineering Military College of Signals(MCS)National University of Sciences and Technology(NUST)Islamabad43000Pakistan Department of Electrical Engineering Sir Syed(Center For Advanced Studies)Institute of Technology(SSCASE)Islamabad43000Pakistan College of Science and Humanities Rumah Majmaah UniversityRumahKingdom of Saudi Arabia

Due to their complex structure,2-D models are challenging to work with;additionally,simulation,analysis,design,and control get increasingly difficult as the order of the model ***,in particular time intervals,Gawronski and Juang’s time-limited model reduction schemes produce an unstable reduced-order model for the 2-D and 1-D *** revealed some stability preservation solutions to address this key flaw which ensure the stability of 1-D reduced-order systems;nevertheless,these strategies result in large approximation ***,to the best of the authors’knowledge,there is no literature available for the stability preserving time-limited-interval Gramian-based model reduction framework for the 2-D discrete-time *** this article,2-D models are decomposed into two separate sub-models(i.e.,two cascaded 1-D models)using the condition of minimal *** reduction procedures are conducted on these obtained two 1-D sub-models using limited-time *** suggested methodology works for both 2-D and 1-D ***,the suggested methodology gives the stability of the reduced model as well as a priori error-bound expressions for the 2-D and 1-D *** results and comparisons between existing and suggested methodologies are provided to demonstrate the effectiveness of the suggested methodology.

关键词： Model reduction Weighted Gramian Limited interval Gramian Minimal realization Approximation error Error bound

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Accuracy Enhancing Time Limited Model Reduction Framework: Computational Efficiency in Power Systems 21

Accuracy Enhancing Time Limited Model Reduction Framework: C...

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21st International Bhurban Conference on Applied Sciences and Technology, IBCAST 2024

作者： Latif, Muhammad Ambreen, Hira Imran, Muhammad Zafar, Samra Imran, Muhammad Bashir, Sajid Sir Syed Center for Advanced Studies in Engineering Department of Electrical Engineering Islamabad Pakistan Department of Electrical Engineering Islamabad Pakistan Henan University School of Computer and Information Engineering Kaifeng475001 China College of Electrical & Mechanical Engineering NUST Islamabad Pakistan

ISBN: (纸本)9798331516680

The analytical and modelling precision required to build modern wind turbines makes them stable, controlled, and observable. This article presents a state-of-the-art method for lowering the model order of a wind turbine driven by a double-fed induction generator, where the rotational speed varies over time. The suggested approach uses state-space representations to set up a comprehensive and systematic framework for analysing wind turbine performance and checking for compliance with grid standards. A time-constrained Gramians-based novel balanced realization approach is employed to reduce the dimensionality of the large-scale wind turbine model. Stability and reduced approximation error are two benefits of the lower-order system. The proposed method also gives researchers an a priori formula for the error-bound, making computations faster and more efficient. Using substantial simulation data, we show that our method improves upon previous methods in optimising models that include wind turbines with changing rotational speeds, taking into account both stability and error computation. To enhance the efficacy and accuracy of their modeling procedures, academics and researchers analyzing wind turbines should incorporate this new methodology. © 2024 IEEE.

关键词： Asynchronous generators

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3D Twist and Tilt Bipedal Model and Control Realization for Sit to Stand

3D Twist and Tilt Bipedal Model and Control Realization for ...

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IEEE International Conference on Multi Topic

作者： Badar Ali Asif Mahmood Mughal Sir Syed Center for Advanced Studies in Engineering Institute of Technology (SS-CASE-IT) Islamabad Pakistan

The field of biomechanics for human voluntary motions in three dimensions encompasses a wide array of applications. The process of transitioning from a seated position to a standing position, referred to as sit-to-stand, is a basic motion that is frequently executed during various everyday tasks. The current investigation centers on enhancing 3D bipedal locomotion through the creation of a novel system utilizing a Twist and Tilt scheme to perform sit-to-stand (STS) movements. This mechanism, in contrast with previous models, does not consider any foot fixed for the whole profile. This type enables one foot to perform a twisting movement and the other foot to perform a tilting movement. The tilt foot schematic is built with two distinct schemes: one involving sliding tilt, the other with rotating tilt. This scheme is designed to study STS issues faced by neurologically deficient human beings while carrying out different joint positions. The twist and tilt models are designed using computer-aided design (CAD) software. They consist of an 8-part bipedal structure, which includes two feet, two calves / shanks, two thighs, one pelvis, and one HAT section. Both of these twist and tilt models are first produced in SOLIDWORKS Corp software. Subsequently, to facilitate control implementation, these models undergo linearization using SIMULINK / SIMSCAPE and MATLAB. By employing the analysis of Controllability and Observability, it is revealed that the design, which incorporates one foot linear tilt, consists of twelve states. Furthermore, it is determined that one foot linear model has full rank controllability and observability and is suitable to design controller.

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Forward Thrust Modelling and Control Optimization of Biped in 3D for Sit to Stand

Forward Thrust Modelling and Control Optimization of Biped i...

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Emerging Trends in Electrical, Control, and Telecommunication engineering (ETECTE), International Conference on

作者： Badar Ali Asif Mahmood Mughal Sir Syed Center for Advanced Studies in Engineering Institute of Technology (SS-CASE-IT) Islamabad Pakistan

Modelling of Biomechanical systems for human voluntary movements in 3D is an area with very broad range of applications. Human motions like sit to stand is one of the very basic movements that human being need to perform a large number of times in daily activities. In the work presented here, we are escalating our 3D bipedal research to develop forward thrust motion trajectories during sit to stand (STS) movements of biped in 3D. We have developed forward thrust reference trajectories for angular profiles. These profiles are the basis for sit to stand (STS) motion for the stroke patients. The model used in this study is the one in which one foot is fixed (healthy leg) and other is allowed 01 DOF linear movement (neurologically deficient leg). Afterwards the LQR based separate controller is designed for the forward thrust model. Rigid body bipedal model in 3D is designed in CAD software SOLIDWORKS Corp., whereas, model linearization is done in SIMSCAPE / SIMULINK. Afterwards, the optimal control for the system is developed in MATLAB / SIMULINK. The forward thrust model having 22 nd order and it is shown in the results that both healthy and paraplegic extremities follows the reference trajectories.

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Modelling and Optimal Control of Human Voluntary Motion in 3D for Bipedal

Modelling and Optimal Control of Human Voluntary Motion in 3...

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Emerging Trends in Electrical, Control, and Telecommunication engineering (ETECTE), International Conference on

作者： Badar Ali Asif Mahmood Mughal Sir Syed Center for Advanced Studies in Engineering Institute of Technology (SS-CASE-IT) Islamabad Pakistan

ISBN: (纸本)9781665492430

Biomechanical modelling in three dimensions of human voluntary motion with motor control is an extremely important field that consists of human intended behaviors. The human body demonstrates extremely complicated motion trajectories with a very high level of mobility and degree of freedom (DOF). In this research, we have extended our 3D biomechanical model research to develop the optimal motor controls that exhibit biomechanical schemes for human sit to stand (STS) motion. The developed three modelling schemes are realized to analyze the motion constraints on rigid body model of human STS motion. Model developed in CAD software SOLIDWORKS Corp. comprising of a 3D 8-segment biped having 2 feet, 2 calf, 2 thigh, a pelvic and a HAT segment is utilized to generate the LQR based optimal control on the developed reference trajectories of each joint. Model having one foot fix and other a 1DOF prismatic joint is utilized for controller development due to its full rank controllability and observability. The optimal control is developed in MATLAB / SIMULINK after linearizing the model in SIMSCAPE / SIMULINK by importing the xml files from SOLIDWORKS. Control system utilized the feedback of position and speed of each joint and generates the torque inputs for the model based on the required reference trajectories. The developed model is of 22 nd order and the results show that all the motor joints followed the reference trajectories.

关键词： Biomechanics Solid modeling Motor drives Three-dimensional displays Software packages Biological system modeling Optimal control

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Hybrid differentiated service architecture for QoS routing in mobile ad hoc networks

Hybrid differentiated service architecture for QoS routing i...

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2009 IEEE 13th International Multitopic Conference, INMIC 2009

作者： Farooq, Muhammad Omer Butt, Anila Sahar Department of Electrical and Computer Engineering Center for Advance Studies in Engineering Sir Syed Memorial Building G-5/1 19 Attaturk Avenue Islamabad Pakistan NUST School of Electrical Engineering and Computer Science National University of Science and Technology Pakistan

ISBN: (纸本)9781424448722

Multimedia applications invariably require guaranteed Quality of Service (QoS) and resource reservation. These requirements have raised numerous challenging technical issues for routing in MANETS. We have proposed a hybrid Differentiated Services Architecture (HDSA) to provide QoS provisioning in dynamic topology based MANET. Our proposed HDSA introduces routing metrics such as available bandwidth within each DiffServ class and delay that are more appropriate for QoS routing rather than the hop distance. In order to guarantee QoS we have introduced semi state-full features to differentiated services architecture along with reduced routing packet propagation overhead. The performance of our distributed algorithm is investigated by examples and simulation in both static and dynamic networks. The gain achieved by HDSA is an important achievement in wireless mobile networks. ©2009 IEEE.

关键词： Quality of service

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Performance increase in CSMA/CA with RTS-CTS 7

Performance increase in CSMA/CA with RTS-CTS

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7th IEEE International Multi Topic Conference, INMIC 2003

作者： Qayyum, A. Saleem, M.U. Tauseef-Ul-Islam Ahmad, M. Khan, M.A. Center for Advance Studies in Engineering Sir Syed Memorial Building 19-Ataturk Avenue G-5/1 Islamabad Pakistan COMSATS Institute of Information Technology Tobe Camp University Road AbbottabadNWFP Pakistan

ISBN: (纸本)0780381831

The wireless medium is inherently a broadcast one: therefore multiple devices can access the same medium at the same time at overlapping frequencies. Multiple simultaneous transmissions in the same frequency area usually result in garbled data making communication impossible or inefficient. The MAC (medium access control) protocol's function is to moderate access to the shared medium by defining rules that allow these devices to communicate with each other in an orderly and efficient manner. There is no clearly defined order for devices in ad hoc networks, and this fact raises the matter of hidden and exposed devices. In this study we analyze how much performance increase is found using MAC protocol CSMA extension named CSMA/CA implemented with RTS-CTS. © 2003 IEEE.

关键词： Network layers

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