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Full-Text Articles in Engineering

Local Orbital-Angular-Momentum Dependent Surface States With Topological Protection, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha May 2020

Local Orbital-Angular-Momentum Dependent Surface States With Topological Protection, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

Chiral surface states along the zigzag edge of a valley photonic crystal in the honeycomb lattice are demonstrated. By decomposing the local fields into orbital angular momentum (OAM) modes, we find that the chiral surface states present OAM-dependent unidirectional propagation characteristics. Particularly, the propagation directivities of the surface states are quantified by the local OAM decomposition and are found to depend on the chirality's of both the source and surface states. These findings allow for the engineering control of the unidirectional propagation of electromagnetic energy without requiring an ancillary cladding layer. Furthermore, we examine the propagation of the chiral surface …


The Heuristic Dynamic Programming Approach In Boost Converters, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi Feb 2020

The Heuristic Dynamic Programming Approach In Boost Converters, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In this study, a heuristic dynamic programming controller is proposed to control a boost converter. Conventional controllers such as proportional-integral-derivative (PID) or proportional-integral (PI) are designed based on the linearized small-signal model near the operating point. Therefore, the performance of the controller during the start-up, the load change, or the input voltage variation is not optimal since the system model changes by varying the operating point. The heuristic dynamic programming controller optimally controls the boost converter by following the approximate dynamic programming. The advantage of the HDP is that the neural network-based characteristic of the proposed controller enables boost converters …


The Voltage Regulation Of A Buck Converter Using A Neural Network Predictive Controller, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi Feb 2020

The Voltage Regulation Of A Buck Converter Using A Neural Network Predictive Controller, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a neural network predictive controller (NNPC) is proposed to control a buck converter. Conventional controllers such as proportional-integral (PI) or proportional-integral-derivative (PID) are designed based on the linearized small-signal model near the operating point. Therefore, the performance of the controller in the start-up, load change, or reference change is not optimal since the system model changes by changing the operating point. The neural network predictive controller optimally controls the buck converter by following the concept of the traditional model predictive controller. The advantage of the NNPC is that the neural network system identification decreases the inaccuracy of …


A Miniaturized Dual-Band Dual-Polarized Band-Notched Slot Antenna Array With High Isolation For Base Station Applications, Min Li, Rong Wang, Jamal Muhammad Yasir, Lijun Jiang Feb 2020

A Miniaturized Dual-Band Dual-Polarized Band-Notched Slot Antenna Array With High Isolation For Base Station Applications, Min Li, Rong Wang, Jamal Muhammad Yasir, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this article, a miniaturized dual-band dual-polarized slot antenna array is proposed for base station applications. It consists of two closely located $1\times 4$ subarrays for the digital cellular system (DCS) and wideband code division multiple access (WCDMA) operations. The band-notched slot antenna (BNSA) is designed and adopted as the subarray element with radiation-suppression characteristic at notch frequencies. The notch frequency for one subarray is designed at the center operating frequency of the other subarray. As a result, the radiation from DCS subarray could be effectively suppressed within the WCDMA band and vice versa, resulting in high isolation between two …


Autonomous Control Of A Line Follower Robot Using A Q-Learning Controller, Sepehr Saadatmand, Sima Azizi, Mohammadamir Kavousi, Donald C. Wunsch Jan 2020

Autonomous Control Of A Line Follower Robot Using A Q-Learning Controller, Sepehr Saadatmand, Sima Azizi, Mohammadamir Kavousi, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a MIMO simulated annealing (SA)-based Q-learning method is proposed to control a line follower robot. The conventional controller for these types of robots is the proportional (P) controller. Considering the unknown mechanical characteristics of the robot and uncertainties such as friction and slippery surfaces, system modeling and controller designing can be extremely challenging. The mathematical modeling for the robot is presented in this paper, and a simulator is designed based on this model. The basic Q-learning methods are based pure exploitation and the ε -greedy methods, which help exploration, can harm the controller performance after learning completion …


Incremental Cluster Validity Indices For Online Learning Of Hard Partitions: Extensions And Comparative Study, Leonardo Enzo Brito Da Silva, Niklas Max Melton, Donald C. Wunsch Jan 2020

Incremental Cluster Validity Indices For Online Learning Of Hard Partitions: Extensions And Comparative Study, Leonardo Enzo Brito Da Silva, Niklas Max Melton, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Validation is one of the most important aspects of clustering, particularly when the user is designing a trustworthy or explainable system. However, most clustering validation approaches require batch calculation. This is an important gap because of the value of clustering in real-time data streaming and other online learning applications. Therefore, interest has grown in providing online alternatives for validation. This paper extends the incremental cluster validity index (iCVI) family by presenting incremental versions of Calinski-Harabasz (iCH), Pakhira-Bandyopadhyay-Maulik (iPBM), WB index (iWB), Silhouette (iSIL), Negentropy Increment (iNI), Representative Cross Information Potential (irCIP), Representative Cross Entropy (irH), and Conn_Index (iConn_Index). This paper …


Numerical Methods For Electromagnetic Modeling Of Graphene: A Review, Kaikun Niu, Ping Li, Zhixiang Huang, Li (Lijun) Jun Jiang, Hakan Bagci Jan 2020

Numerical Methods For Electromagnetic Modeling Of Graphene: A Review, Kaikun Niu, Ping Li, Zhixiang Huang, Li (Lijun) Jun Jiang, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

Graphene's remarkable electrical, mechanical, thermal, and chemical properties have made this the frontier of many other 2-D materials a focus of significant research interest in the last decade. Many theoretical studies of the physical mechanisms behind these properties have been followed by those investing the graphene's practical use in various fields of engineering. Electromagnetics, optics, and photonics are among these fields, where potential benefits of graphene in improving the device/system performance have been studied. These studies are often carried out using simulation tools. To this end, many numerical methods have been developed to characterize electromagnetic field/wave interactions on graphene sheets …


Enhanced Pml Based On The Long Short Term Memory Network For The Fdtd Method, He Ming Yao, Lijun Jiang Jan 2020

Enhanced Pml Based On The Long Short Term Memory Network For The Fdtd Method, He Ming Yao, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a new absorbing boundary condition (ABC) computation approach based on the deep learning technique. Benefited from the sequence dependence feature, the Long Short-Term Memory (LSTM) network is employed to replace the conventional perfectly matched layer (PML) ABC for the Finite-Difference Time-Domain (FDTD) solving process. The newly proposed LSTM based PML model is trained by the electromagnetic field data on the interface of the conventional PML. Different from the conventional PML, the newly proposed model only needs one cell layer as the boundary. Hence, the newly proposed method conveniently reduces both the algorithm's complexity and the area of …


Electromagnetic-Circuital-Thermal Multiphysics Simulation Method: A Review, Huan Huan Zhang, Pan Pan Wang, Shuai Zhang, Long Li, Ping Li, Wei E.I. Sha, Li (Lijun) Jun Jiang Jan 2020

Electromagnetic-Circuital-Thermal Multiphysics Simulation Method: A Review, Huan Huan Zhang, Pan Pan Wang, Shuai Zhang, Long Li, Ping Li, Wei E.I. Sha, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic-circuital-thermal multiphysics simulation is a very important topic in the field of integrated circuits (ICs), microwave circuits, antennas, etc. This paper presents a comprehensive review of the state of the art of electromagnetic-circuital-thermal multiphysics simulation method. Most efforts were focused on electromagnetic-circuital co-simulation and electromagnetic-thermal cosimulation. A brief introduction of related theories like governing equations, numerical methods, and coupling mechanisms is also included.


A Novel Data-Driven Scheme For The Ship Wake Identification On The 2-D Dynamic Sea Surface, Yanming Zhang, Lijun Jiang Jan 2020

A Novel Data-Driven Scheme For The Ship Wake Identification On The 2-D Dynamic Sea Surface, Yanming Zhang, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Because the ship wake spreads into an area much larger than that of the ship hull in the sea surface, it has been widely used in the ship detection. However, due to the complex sea wave motion and the high sea state, the ship wake detection is still a challenging task. In this paper, we propose a novel data-driven method based on dynamic mode decomposition (DMD) to detect, reconstruct, and locate the Kelvin wake on the two-dimensional dynamic sea surface. Through the proposed method, the sea's dynamic characteristics including the oscillation frequency and decay/growth rate of ship wakes and the …


A Novel Calculation Method To Design Parasitic Decoupling Technique For Two Antennas, Min Li, Di Wu, Bing Xiao, Kwan Lawrence Yeung, Lijun Jiang Jan 2020

A Novel Calculation Method To Design Parasitic Decoupling Technique For Two Antennas, Min Li, Di Wu, Bing Xiao, Kwan Lawrence Yeung, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a systematic and calculation-based parasitic decoupling technique (PDT) is proposed to mitigate the mutual coupling between two closely coupled antennas. The adopted parasitic decoupling structure consists of two transmission lines connected to the feed lines of antennas and a parasitic element connected with a transmission line and terminated by a reactive load. Rigorous decoupling theory and systematic design procedures are presented. The lengths of transmission lines and value of reactive load can be precisely calculated to increase antenna isolation. The superiority of the proposed PDT is verified by four decoupling examples. The simulated and measured results show …


Pseudospin-Polarized Topological Line Defects In Dielectric Photonic Crystals, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha Jan 2020

Pseudospin-Polarized Topological Line Defects In Dielectric Photonic Crystals, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic (EM) topological insulators have been extensively explored due to the robust edge states they support. In this work, we propose a topological EM system based on a line defect in topologically nontrivial photonic crystals (PCs). With a finite-difference supercell approach, modal analysis of the PC structure is investigated in detail. The topological line-defect states are pseudospin polarized and their energy flow directions are determined by the corresponding pseudospin helicities. These states can be excited by using two spatially symmetric line-source arrays carrying orbital angular momenta. The feature of the unidirectional propagation is demonstrated, and it is stable when disorders …