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Multi-source Network-coded D2D Cooperative Content Distribution Systems
Weijun Xing,Fuqiang Liu,Chao Wang,Ming Xiao,Ping Wang 한국통신학회 2018 Journal of communications and networks Vol.20 No.1
In this paper, we investigate the information transmissionin a typical 5G device-to-device (D2D) communication applicationscenario, i.e., a content distribution system with a numberof information sources intending to broadcast their messages tomultiple destinations in the vicinity. Due to the dynamic natureof wireless signal propagation links, it is hard to guarantee a satisfactoryperformance by direct source-destination transmissions,especially when the system is operating in a reuse-mode. Relays canbe introduced to the system to solve this problem. However, adoptingthe conventional repetition coding at relays inefficiently utilizesthe available resources, for the considered multi-source scenario. Therefore, we investigate applying a class of finite-field networkcodes at the relays, when potentially three types of relays are deployedto assist the information distribution process. We proposedthe algorithms to derive the system outage probability and analyzethe trade-off between energy efficiency and spectral efficiency. Ouranalytical and numerical results clearly demonstrate the potentialof exploiting network-coded cooperative communications in future5G D2D systems.
Analysis of inner flow in low specific speed centrifugal pump based on LES
Weijun Wang,Yang Wang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6
To investigate unsteady flow in the low specific speed centrifugal pump, a three-dimensional model of a pump that ns is equal to 50 is modeled with the software Pro/E. With standard k-ε, SST k-ω and RNG k-ε turbulence model, the testing performance of pump is compared with the simulated results. Based on the result of steady flow, the unsteady flow of RNG k-ε turbulence model and large eddy simulation (LES) are calculated at both design and off-design conditions. The time domain of pressure fluctuation value of indicator points, which are located interfaces between volute and impeller, has been investigated numerically. The unsteady flow characteristic of pump with RNG k-ε turbulence model is compared with LES. The distribution of vortex in the volute is discovered. The results show that in steady flow, an error of 2.6% of RNG k-ε is the lowest, SST k-ω of 3.65% is second and the worst is standard k-ε of 4.78% at design condition. The calculated precision using RNG k-ε model is highest in steady condition. Because of the interaction of relative movement between volute and impeller, the pressure fluctuation can clearly be observed. The flow separation of the blade pressure surface and the stall channels in off-designed condition is the reason that the efficiency of pump operating under off-design condition is low. The vortex intensity is obviously different in the eight sections of the volute and is gradually increasing from first section to eighth section. Large eddy simulation can discover the unsteady flow of the centrifugal pump effectively.
Analysis and Design of 3-DOF Parallel Mechanism Based on Kinematic Couplings
왕위준(Weijun Wang),한창수(Changsoo Han) 한국생산제조학회 2012 한국생산제조학회지 Vol.21 No.3
This paper presents a high-speed automatic micro-alignment system that is a part of an inspection machine for small-sized molded lenses of mobile phones, palm-top computers, and so on. This work was motivated by the shortcomings of existing highest-grade commercial machine. A simple tip/tilt/Z parallel mechanism is designed based on kinematic couplings, which is a 3-degree-of-freedom (3-DOF) moderate-cost alignment stage. It is used to automatically adjust the posture of each lens on the tray, which is impossible by the conventional instrument. Amplified piezoelectric actuators are used to ensure the accuracy and dynamic response. Forward kinematic analysis and simulation show that the parasitic motion is small enough compared to the actuator stroke. From the workspace analysis of the moving platform, it is clear that the output motion range satisfies the design requirements.
Evaluating Wealth Management Centers in the Pearl River Delta by Using Principal Component Analysis
Weijun Xu,Shaoying Huang,Zhiqiang Wang 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.12
Because of the rapid development and wealth accumulation in the Pearl River Delta (PRD), most of the cities in this area are motivated to establish wealth management centers (WMCs). We create an evaluation index system for assessing the development level of WMCs in cities in the PRD; we develop this system by selecting 20 indicators including gross regional production (GDP). Subsequently, we use panel data from 2010 to 2013 of nine cities in the PRD to evaluate the financial competitiveness of each of these cities through principal component analysis (PCA); we further analyze the pioneering roles of Guangzhou and Shenzhen in establishing WMCs in the PRD. The numerical analysis results reveal that Shenzhen and Guangzhou rank first and second, respectively, regarding financial competitiveness in the PRD, indicating that the two cities play a leading role in the establishment of WMCs in the PRD.
Weijun Peng,Huilan Chen,Wei Wang,Yanfang Huang,Guihong Han 한국물리학회 2020 Current Applied Physics Vol.20 No.2
The NiCo2S4 nanospheres arrayed on the surface of reduced graphene oxide (rGO) was fabricated via one-step hydrothermal method. The effect of initial feeding mass of Ni(NO3)2·6H2O and Co(NO3)2·6H2O to rGO on the microstructure and electrochemical performance of the as-prepared composites was studied. The results indicated that the specific capacitances of the composites were first increased and then reduced due to the aggregation of NiCo2S4 nanospheres. NiCo2S4 nanospheres/rGO composites exhibited a remarkable specific capacitance of 1406 F/g and excellent cyclic stability of 82.36% at the current density of 1 A/g, which were better than those of individual NiCo2S4 (792 F/g and 64.77%) counterpart. These results showed that the as-prepared NiCo2S4 nanospheres/rGO composites were outstanding candidate for electrode material of supercapacitors
A Multicast Routing Algorithm Based on Prior Objective Nodes
Weijun Yang,Xiaodong Wang,Yuanfeng Chen 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.10
The minimum Steiner tree problem is an NP-complete problem in multicast routing algorithms. In this paper, an improved algorithm called the prior nodes minimum cost path heuristic (PNMPH) algorithm is presented according to the shortage of the minimum cost path heuristic (MPH) algorithm, in which some paths that pass through prior destination nodes are selected first. It partly shares links in the network and decreases the cost of the multicast routing tree. It is also closer to the optimal solution with the time complexity O(n3). The simulation results on the existing networks show that the cost of the PNMPH algorithm is lower than that of the MPH algorithm in the case of more than 90%.
( Yu Wang ),( Wen Zhou ),( Chongchong Yu ),( Weijun Su ) 한국정보처리학회 2021 Journal of information processing systems Vol.17 No.1
Alzheimer’s disease (AD) is an insidious and degenerative neurological disease. It is a new topic for AD patients to use magnetic resonance imaging (MRI) and computer technology and is gradually explored at present. Preprocessing and correlation analysis on MRI data are firstly made in this paper. Then kernel principal component analysis (KPCA) is used to extract features of brain gray matter images. Finally supervised classification schemes such as AdaBoost algorithm and support vector machine algorithm are used to classify the above features. Experimental results by means of AD program Alzheimer’s Disease Neuroimaging Initiative (ADNI) database which contains brain structural MRI (sMRI) of 116 AD patients, 116 patients with mild cognitive impairment, and 117 normal controls show that the proposed method can effectively assist the diagnosis and analysis of AD. Compared with principal component analysis (PCA) method, all classification results on KPCA are improved by 2%-6% among which the best result can reach 84%. It indicates that KPCA algorithm for feature extraction is more abundant and complete than PCA.