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Distributed Fair Resource Allocation for Cognitive Femtocell Networks
Shi, Lin,Yoo, Sang-Jo Kluwer Academic Publishers 2017 WIRELESS PERSONAL COMMUNICATIONS Vol. No.
<P>The emergence of femtocell and cognitive radio technology has led them to be considered promising solutions for improved wireless broadband access. The low-power and short-range femtocells equipped with cognitive functionality allow opportunistic access to the macro spectrum by sensing the wireless environment. A key role is to dynamically allocate available resources in the most efficient manner and manage the interference effectively. However, the issue of fair resource allocation is also an important problem to be addressed in cognitive femtocell networks. In this paper, we propose a distributed fair resource allocation scheme in a cognitive femtocell network while mitigating the inter-cell interference. The proposed distributed fair resource allocation (DFRA) algorithm guarantees fairness by applying channel state difference ranks and satisfaction degrees of femtocells. Additionally, the DFRA algorithm works in a fully distributed manner reducing the signal overhead compared to centralized schemes. Simulation results indicate that the proposed DFRA algorithm is able to significantly improve fairness among femtocells while maintaining considerable throughput performance.</P>
Shi, Lin,Ahmad, Ishtiaq,He, YuJing,Chang, KyungHi Editorial Department of Journal of Communications 2018 Journal of communications and networks Vol.20 No.5
<P>The development of drones has captured the attention of hobbyists and investors alike; drones now have greater commercial and military applications owing to their relatively small size and ability to fly without an on-board pilot. However, certain drone applications may pose serious threats to public safety. The most important problem to be addressed is the recognition of drones in security-sensitive areas. This paper presents an approach to recognize drones through sounds emitted by their propellers using Mel frequency cepstral coefficients (MFCCs) technique for feature extraction and the hidden Markov model (HMM) approach for classification. In the feature extraction stage, two schemes for feature vectors (one using twenty-four MFCCs and the other using the proposed thirty-six MFCCs) are applied, where additional dynamic information of the features is added in the latter. The classifier based on HMMs is then trained using the extracted features according to different training datasets in order to validate the effect of the number of sound types in each cluster on the recognition rate performance. We perform experiments for drone sound recognition utilizing various training datasets for the purpose of classifier optimization, as well as for the two MFCC schemes that are applied in each trial, using the same training datasets for a fair comparison. The experimental results finally validate the feasibility and effectiveness of our proposed methods with relatively high recognition rates, even in noisy environments.</P>
Shi, Lin,Liu, Bangyin,Duan, Shanxu The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
A current balance problem exists in multi-phase LLC converters due to the resonant parameter tolerance. This paper presents a current balancing method for interleaved three-phase half bridge LLC converters. This method regulates the phase shift angle of the driving signals between the three phases based on a converter with a floating Y-connection. The floating midpoint voltage has different influences on each phase current and makes the three-phase current balance performance better than midpoint non-floating systems. Phase shift control between modules can further regulate the midpoint voltage. Then three phase current sharing is realized without adding extra components. The current distributions in a midpoint non-floating system and a midpoint floating system are compared. Then the principle and implementation of the proposed control strategy are analyzed in detail. A 3kW prototype is built to verify the validity and feasibility of the proposed method.
Locate and Detect Persons in Crowded Scenes Aided by Objectiveness Measure
Shilin Zhang,Xunyuan Zhang 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6
Locating persons in crowded scenes is very difficult due to multi-resolution and complex environment. The other difficulty in pedestrian detection domain is the real time requirement, because the camera installed on the crossing road is in high definition. In this paper, we presented a multi-task pedestrian detection framework boosted by Bing feature. We firstly trained upright full-body, multi-person, half-body and head models, then we compute the object-ness score and generate 1000 proposals by Bing feature, and at last we apply different model to different aspect ratio of the detection proposals. The experiment results on the PASCAL VOC 2007 show that our method outperforms all the other methods and achieved lower miss rate than the state-of-the-art. The computation time cost is just the half of state-of-the-art method.
Crowded Pedestrian Detection and Density Estimation by Visual Words Analysis
Shilin Zhang,Xunyuan Zhang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.3
Crowded pedestrian detection and density estimation are very useful and important under transportation environment. In this paper, we present a novel method for crowded pedestrian detection and density estimation through a weighting scheme of bag of visual words model which characterizes both the weight and the relative spatial arrangement aspects of visual words in depicting an image. Firstly, we analyze the visual words generation process. We give each visual word a weight by counting the number of images through which each visual word is clustered and computing the cluster radius of each visual word. To be more specifically, the co-occurrences of visual words are computed with respect to spatial predicates over a hierarchical spatial partitioning of an image. We validate this method using a challenging ground truth pedestrian dataset Pascal VOC 2007. Our approach is shown to be more accuracy than a non-weighting bag-of-visual-words one. The algorithm’s cost is also more efficient than the competing pairs.
Design optimization of vibration isolation system through minimization of vibration power flow
Shilin Xie,Siu Wing Or,Helen Lai Wa Chan,Ping Kong Choy,Peter Chou Kee Liu 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6
A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.
Shilin Song,Huijuan Wang,Yuyue Huang,Yixing Ma 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4
In this paper, the chemical and physical effects generated during the dielectric barrier discharge plasma (DBDP) process, including O₃, H₂O₂, light, e<SUP>*</SUP>, etc., were utilized to activate the peroxydisulfate (PDS) to form SO₄<SUP>−</SUP>•. Then, the original reactive oxygen species (ROS), such as •OH, formed in the discharge system was combined to degrade the enrofloxacin (ENR) in water, and the corresponding influencing parameters and reactive substance in the DBDP/PDS system were analyzed. From the investigation, it was found that the neutral (pH =6.5) solution was more conducive to the ENR decomposition than the acidic and alkaline solution conditions. The presence of Fe<SUP>2+</SUP> and Cu<SUP>2+</SUP> in the reaction solution could hasten the ENR degradation, whereas the addition of Cl<SUP>−</SUP> and the HCO₃<SUP>−</SUP> in the solution had a negative effect. Analysis of the reactive species and quenching tests were carried out to explore the generation of H₂O₂, O₃, •OH, and SO₄<SUP>−</SUP>• in the DBDP/PDS system and their effects on the ENR degradation. The UV-Vis and 3D fluorescence spectra analysis were applied to demonstrate the cooperative effects of the DBDP and the PDS. The TOC and COD removals of the ENR solutions in the DBDP and the DBDP/PDS systems were also compared. Based on the intermediates analysis of the ENR degradation, three possible pathways of ENR decomposition in the synergistic system have been inferred.