Chunlin Ji

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Papers by Chunlin Ji

Effect of the Multiple Cylinders Scattering of an Electromagnetic Plane Wave on the Formation of Whispering Gallery Modes

DEStech Transactions on Materials Science and Engineering, Jun 23, 2017

We report on the effect of scattering by multiple cylinders of an electromagnetic plane wave on t... more We report on the effect of scattering by multiple cylinders of an electromagnetic plane wave on the formation of whispering gallery modes (WGM) in the cylinder. It was found that WGM can arise thanks to the presence of additional cylinder scatterers, and at their special location, while WGM in a single cylinder can be formed only for specially chosen values of the cylinder radius and (or) wave length, and the accuracy of these matching should be much more than required in our model for the location of the additional cylinders. The analysis of the general solution of considered scattering problem has shown that the effect can be explained by the interference of waves scattered by additional cylinders (i) and incident on the main cylinder (ii).

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Cross-entropy optimisation of multiple-input multiple-output capacity by transmit antenna selection

Iet Microwaves Antennas & Propagation, 2007

Radio channel capacity can be increased dramatically using a multiple-input multiple-output (MIMO... more Radio channel capacity can be increased dramatically using a multiple-input multiple-output (MIMO) scheme, but at the expense of hardware complexity. An efficient approach for complexity reduction is antenna subset selection at the transmitter and/or receiver. A novel transmit antenna selection algorithm is presented using the cross-entropy optimisation method to maximise channel capacity. In contrast with the existing work, the proposed algorithm guarantees a result to within 99% of the true optimum (i.e. the maximal capacity with selected transmit antennas) with substantially low complexity. The simulation results indicate that the proposed algorithm is independent of the relationship between the selected transmit array size and receive array size. The proposed scheme has the potential to make practical MIMO systems with high performance simpler to implement.

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Resolution Enhancement Based on Antenna Aperture Compensation in Synthetic Aperture Radar Imaging with Hyper-Laplacian Prior Deconvolution

IEEE Sensors Journal

Single Deterministic Neural Network with Hierarchical Gaussian Mixture Model for Uncertainty Quantification

Lecture Notes in Computer Science, 2022

Adaptive Monte Carlo Methods for Bayesian Inference

Deep Grasping Prediction with Antipodal Loss for Dual Arm Manipulators

The cooperative manipulators can execute a wide range of tasks, such as carrying large or heavy p... more The cooperative manipulators can execute a wide range of tasks, such as carrying large or heavy payloads, which are difficult for a single manipulator. Dual arm manipulators are in typically operative configuration to mimic human, which are of highly flexibility and dexterity. In this paper, we propose a novel coarse-to-fine deep learning model along with investigating the grasp prior loss based on the well-known antipodal force-closure property. The proposed deep learning model predicts the contact configurations in grasping over-loaded and over-sized objects for dual arm manipulators directly from raw RGB images. We first apply detection network to locate the coarse bounding box of objects, further apply a fine-predicting network on the bounding box clipped images to precisely generate two contact configurations via minimizing regression loss and the antipodal grasp prior loss. Extensive experimental results under dense clutter and occlusion strongly demonstrate the effectiveness ...

On the recognition of spontaneous emotions in spoken Chinese

2017 International Conference on Security, Pattern Analysis, and Cybernetics (SPAC)

Acoustic emotion recognition has been an active research area. This paper presents a new Chinese ... more Acoustic emotion recognition has been an active research area. This paper presents a new Chinese corpus of emotionally colored conversations. Two discrete 3-point scaled emotion primitives are used to describe emotions, namely valence and arousal. Acoustic feature extraction is carried out using OpenSMILE toolkit. For the estimation of these primitives, Support Vector Machine (SVM) is used for the classification task. Preliminary classification results show the effectiveness of the proposed method.

Diviseur De Puissance À Té Magique

On Bayesian Inference for Continuous-Time Autoregressive Models without Likelihood

2018 21st International Conference on Information Fusion (FUSION), 2018

Continuous-time autoregressive (CAR) model is very powerful when modeling many real world continu... more Continuous-time autoregressive (CAR) model is very powerful when modeling many real world continuous processes. When the model is driven by Brownian motion, parameter inference is usually based on the likelihood calculation using the Kalman filter; while the model is driven by non-Gaussian Lévy process, Monte Carlo type of methods are often applied to approximate the likelihood. In both cases, likelihood evaluation is the key but is not always easy. Here we propose an innovative Bayesian inference method without the requirement of likelihood evaluation. The algorithm is in a framework of approximate Bayesian computation (ABC). Distance correlation is employed as a very flexible summary statistics for ABC and the p-value calculated from distance correlation provides a good measurement of the dependence between generated samples. Simulation study shows that this approach is straightforward and effective in inferring CAR model parameters.

Mechanical and thermodynamic properties study of Al-based binary and ternary solid solutions using the pseudoatomic potential method

Intermetallics, 2020

One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nu... more One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nutritious food for all, do so in an environmentally sustainable and safe manner, while addressing the multiple burdens of undernutrition, overweight and obesity and micronutrient deficiencies. The food security directive focuses predominantly on ensuring the world is producing and consuming enough calories in bulk to reduce hunger and safeguard survival, as opposed to a goal that includes nutrition for well-being and development. To advance the dialogue, it is necessary to consider the ethical questions that swirl around integrating nutrition into the food security paradigm. The health, environmental, economic, and societal costs will be substantial if we do not change our course of action when it comes to feeding the world. Yet solving this problem is riddled with ethical and moral implications. Key ethical issues to consider include how to make societal decisions and define values about food security that impact nutrition outcomes, and the ethical trade-offs between environmental sustainability and ensuring that individual dietary and nutritional needs are met. Such complex issues underscore the need to articulate the broader ethical landscape of the nutrition debate within global food security.

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From object detection to text detection and recognition: A brief evolution history of optical character recognition

WIREs Computational Statistics, 2021

Text detection and recognition, which is also known as optical character recognition (OCR), is an... more Text detection and recognition, which is also known as optical character recognition (OCR), is an active research area under quick development with a lot of exciting applications. Deep‐learning‐based methods represent the state‐of‐art of this area. However, these methods are largely deterministic: they give a deterministic output for each input. For both statisticians and general users, methods supporting uncertainty inference are of great appeal, leaving rich research opportunities to incorporate statistical models and methods with the established deep‐learning‐based approaches. In this paper, we provide a comprehensive review of the evolution history of research development on OCR with discussions on the statistical insights behind these developments and potential directions to enhance the current methods with statistical approaches. We hope this article can serve as a useful guidebook for statisticians who are seeking for a path toward edge‐cutting research in this exciting area.

Adaptive Extrinsic Information Scaling for Concatenated Zigzag Codes Based on Max-Log-APP

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2018

Impedance matching component

Bounded approximations for marginal likelihoods

We discuss novel approaches to evaluation of both upper and lower bounds on log marginal likeliho... more We discuss novel approaches to evaluation of both upper and lower bounds on log marginal likelihoods for model comparison in Bayesian analysis. From posterior Monte Carlo samples, we show how existing variational approximation methods defining lower bounds on marginal likelihoods can be extended to also define upper bounds, and develop optimization methods to minimize such upper bounds. Further, using this new approach to upper bound evaluation, we suggest and exemplify a new quasi-optimized lower bound that can often be obtained with trivial computations compared to current methods. We further discuss the use of partial analytic marginalization of some model parameters as a way of significantly reducing the differences between upper and lower bounds to improve marginal likelihood approximation. To implement this, however, traditional variational methods are intractable, and we provide solution in terms of a novel Monte Carlo Stochastic Approximation (MCSA). We provide theoretical results on convergence of the resulting approximations to true bounds, and several simulation examples in regression and mixture models to demonstrate the accuracy and efficacy ofthe new

What Exercise of the Source Inversion Validation BlindTest I didn't Tell You?

Study on a high spectrum modulation by introducing intersymbol interference

2016 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC), 2016

The design of the communication system follows the Nyquist intersymbol interference (ISI) criteri... more The design of the communication system follows the Nyquist intersymbol interference (ISI) criterion, which explains the design principle of the transmitting and receiving filters to mitigate the effects of ISI. In this work, we study how to utilize the ISI to benefit a communication system. We propose a novel modulation framework, which transmits the constellation symbols much faster than the Nyquist rate and therefore introduces heavy interference between consecutive symbols. The benefit of such modulation is that the frequency bandwidth of the modulated symbols is significantly compressed compared to the traditional modulated symbol with the same symbol rate. We discuss the demodulation process and present a particle filtering-type approximation demodulation method. Numerical simulation and comparison study demonstrate that under an achievable signal noise ration condition the meta-modulation realize a high spectrum efficiency, which is impossible to implement in the traditional QAM system.

Physical Limits of Electromagnetic Responses of Layered Stacked Structures

Progress In Electromagnetics Research Letters, 2019

In this paper, we theoretically investigate the electromagnetic response of the widely used layer... more In this paper, we theoretically investigate the electromagnetic response of the widely used layered stacked structure. For a causality and lossy system, relationships between maximum values of reflection and transmission coefficients are demonstrated, which are related with many parameters, such as absolute bandwidth, layers thicknesses and real parts of the static permittivity and static permeability. Different polarizations and incident conditions are discussed. The results can provide a criterion to judge different designs operating at different spectrum ranges with different thicknesses and materials by comparing them with achievable physical limits.

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Equivalent Circuit Model of Square Patch FSS Using Vector Fitting

The analysis and equivalent circuit modeling of square patch FSS adopting an efficient vector-fit... more The analysis and equivalent circuit modeling of square patch FSS adopting an efficient vector-fitting is proposed. The simulations of microstructure are performed with CST Microwave Studio on single-substrate for different physical parameters, angle of incidences and polarizations. Then circuit model is extracted and developed using vector-fitting tool and implemented in SPICE (Simulation Program with Integrated Circuit Emphasis) simulator for both time and frequency analyses. ADS SPICE generator is used for validating the proposed circuit model. The developed model is within 1% of average deviation against the results obtained from the EM simulation and traditional circuit model.

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Procédé et système de sélection d'antennes en vue d'une communication entre le côté récepteur et le côté émetteur d'un système mimo sans fil

L'invention concerne un procede de selection d'antennes (6, 10; 32, 48-50) en vue d'u... more L'invention concerne un procede de selection d'antennes (6, 10; 32, 48-50) en vue d'une communication entre le cote recepteur et le cote emetteur d'un systeme MIMO sans fil, le procede comprenant les etapes consistant a obtenir des informations d'etat de canal representatives de fonctions de transfert par canal entre des combinaisons d'antennes emettrices et receptrices, et a executer au moins une fois un algorithme iteratif destine a calculer un vecteur de parametres optimises pour une famille de fonctions parametrees discretes de densite de probabilite attribuant une plus forte probabilite aux etats representant une selection d'antennes donnant une valeur plus souhaitable d'une fonction cible sur la base des informations d'etat de canal et d'une valeur optimisee de la fonction cible calculee pour au moins un etat echantillon pris au moins en partie suivant la fonction de densite de probabilite obtenue a l'aide du vecteur de parametres co...

Procédé et Appareil D'Attribution De Spectre De Fréquence Pour Système De Multiplexage Avec Chevauchement, Support De Stockage et Processeur

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