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Research on the Localization Algorithm of Transmitting Station Based on RSSI and GPS
Mingji Yang,Chenyi Zhan,Haoqun Shi 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.5
This paper presents an intelligent positioning algorithm for transmitting station. By using GPS and RSSI, the influence of RSSI value can be reduced. The advantages of multi angle positioning method and centroid localization method are combined. The algorithm required less precision positioning device, also the least square method is used to reduce the error of location in urban areas. The method is simple and convenient, and the simulation results show the practicability of the algorithm.
An Improved BER-Optimal Relay Selection Scheme for Decode-and-Forward Cooperative Networks
Yuhui Han,Mingji Yang,Aili Wang 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.1
We are concerned with the relay selection in a decode-and-forward cooperative network to minimize the bit error rate (BER) in a radio cell. This problem can be solved using maximum weighted (MW) matching algorithm, greedy matching algorithm or worst-link-first (WLF) matching algorithm. Among the algorithms, WLF matching algorithm has achieved much attention for its being less complex while the achieved performance is high. In order to further reduce the computational complexity, we propose an improved WLF relay selection scheme, in which relays are selected according to instantaneous channel state information (CSI) and a cooperative threshold is set up to eliminate some unsatisfying candidate relays from the set of alternative candidate relays and thus reduce the amount of calculation. Theory analysis and simulation results both show that the improved WLF relay selection scheme proposed can be easily implemented and achieve almost the same BER performance as that of WLF scheme while the computational complexity is much lower.
Mingjie Zhang,Jian Gang Yang,Wanjun Xu,Yalei Xia 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5
Minimizing unwanted leakage between stationary and rotating parts is the main function of annular seals. A Mixed labyrinth seal (MLS) with two specially designed lateral teeth installed on a Staggered labyrinth seal (SLS) is proposed to improve seal performance. A 3D computational fluid dynamics calculation model of MLS is set up. The twin vortex structure that appears in the seal cavity and flow path is more complicated in MLS than in SLS. MLS reduces leakage by about 30 % compared with SLS. Rotordynamic analysis of MLS is also conducted by calculating cross-coupled stiffness. The cross-coupled stiffness of MLS is about 75 % to 85 % that of SLS. The dependence of seal performance on the parameters of the lateral teeth is investigated through a simulation test. The lateral teeth should be set in the middle of the seal cavity, and the gap between the two lateral teeth should be similar to the tip clearance.
Mingjie Zhang,Jian Gang Yang,Wanfu Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3
Rotordynamic instability problem caused by seal force widely exists in turbomachines. The fluid-induced force in the seal is determined by the pressure distribution associated with the flow field structure, particularly with the circumferential flow characteristics. In the previous study, the authors found that the helix-comb seal can effectively change the circumferential flow field. The specially designed helical deflectors can reverse the circumferential flow direction of the fluid inside the seal. A considerable static stability enhancement is obtained. However, the transient rotordynamic characteristics of the helix-comb seal are not reported. In the present study, the transient rotordynamic characteristics of the helix-comb seal are investigated further. The rotordynamic coefficients, effective damping, and aerodynamic work of the helix-comb seal are calculated and compared with those of the labyrinth seal. Results reveal that compared with the labyrinth seal, the helix-comb seal considerably improves rotordynamic stability, particularly at a high preswirl ratio. The desirable rotordynamic stability can be obtained with flow field control.
Blocking Variable Step Size Forward-Backward Pursuit Algorithm for Image Reconstruction
AiliWang,Mingji Yang,Xue Gao,Yuji Iwahori 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.2
Compressed sensing is a new signal sampling theory that fully makes use of signal’s sparsity or compressibility. The theory shows that, the acquisition of a small amount of the sparse or compressible signal value can be used for exact signal reconstruction. Based on the study and summarization of the existing reconstruction algorithms, this paper proposes a novel blocking variable step size forward-backward pursuit (BVSSFBP). This paper proposed variable step size forward-backward pursuit algorithm by introducing the concept of sparse phase and variable step size to deal with different situations. The algorithm also divides two-dimensional image into blocks, in order to reduce the scale of observation matrix during single processing, reduce the single processing speed and the overall running time. Experimental results show BVSSFBP algorithm can obtain better reconstructed image quality.
Optimization for Real-Time Object Tracking-by-Detection using Deep Neural Network on Embedded System
Cheng-Bin Jin,Mingjie Liu,Bin Yang,Xuenan Cui,Hakil Kim 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6
This paper introduces a real-time object tracking-by-detection system on embedded boards. A backbone network of single-shot multi-box detectors is proposed using network optimizations for processing time and accuracy. In addition to processing time and accuracy, energy efficiency is an important issue in autonomous driving systems. Therefore, a sparse and independent local network architecture is further applied to train convolution filters of the backbone network. The object detector is followed by an online multiple-object tracker that uses multiple information points, including motion predicted by a Kalman filter, intersection over the union, and shape information. In addition, this paper trains the object detector on real and synthetic data generated using generative adversarial networks. This hybrid dataset minimizes the cost of manual annotation. The proposed tracking-by-detection algorithm demonstrates the best performance among real-time models on the KITTI test benchmark and has a reasonable processing time compared to the other models.