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Autonomous Robot Driving Decision Strategy Following Road Signs And Traffic Rules
Zheng-Hao Chong,Ling Yee,Albert Causo,I-Ming Chen 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10
Autonomous robot driving decision strategy following road signs and traffic rules is described using simulation with a Turtlebot [1]. A fully autonomous robot driving strategy is presented, which follows human level logic in decision making. A vision-based autonomous vehicles navigation system for road vehicles includes three main parts: 1) road and traffic signs detection; 2) vehicle movement guidance system; and 3) decision making following human level logic. The first two modules have been studied independently for many years and obtained many good results using different solutions, but there is little research in fully integrated system with high level decision making to achieve fully autonomous robot navigation following road signs. It is valuable to study and apply this concept into a real system. A simulation world is built according to real environment scenario proving the concept of study.
Effects of Ohmic Area Etching on Buffer Breakdown Voltage of AlGaN/GaN HEMT
Chong Wang,Xiao-Xiao Wel,Meng-Di Zhao,Yun-Long He,Xue-Feng Zheng,Wei Mao,Xiao-Hua Ma,Jin-Cheng Zhang,Yue Hao 한국전기전자재료학회 2017 Transactions on Electrical and Electronic Material Vol.18 No.3
This study is on how ohmic area etching affects the buffer breakdown voltage of AlGaN/GaN HEMT. The surfacemorphology of the ohmic metal can be improved by whole etching on the ohmic area. The buffer breakdown voltagesof the samples with whole etching on the ohmic area were improved by the suppression of the metal spikes formedunder the ohmic contact regions during high-temperature annealing. The samples with selective etching on theohmic area were investigated for comparison. In addition, the buffer leakage currents were measured on the differentradii of the wafer, and the uniformity of the buffer leakage currents on the wafer were investigated by PL mappingmeasurement.
Zheng, Ming-Shan,Lee, Yeun-Kyung,Li, Ying,HwangBo, Kyoung,Lee, Chong-Soon,Kim, Jae-Ryong,Lee, Sunny Kyung-Seon,Chang, Hyun-Wook,Son, Jong-Keun 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.9
Twenty five compounds including ten triterpenes (1-3, 5-11), six flavonoids (12-15, 24, 25), five lignans (17, 18, 21-23), two butenyl clohexnone glycosides (19-20), one fructofuranoside (16) and one fatty acid (4) were isolated from the roots of Ulmus davidiana var. japonica. The structures of those compounds were identified by comparing their physicochemical and spectral data with those of published in literatures. All the compounds were evaluated for DNA topoisomerase inhibitory activities and cytotoxicities. Among the purified compounds, 4 and 19 showed more potent inhibitory acitivities ($IC_{50}$: 39 and 19 ${\mu}M$, respectively) than camptothecin, as the positive control ($IC_{50}$: 46 ${\mu}M$) against topoisomerase I. Compounds, 4, 10, 12, 19, 24 and 25 showed strong inhibitory activities toward DNA topoisomerase II ($IC_{50}$: 0.1, 0.52, 0.47, 0.42, 0.17 ${\mu}M$ and 17 nM, respectively), which were more potent than that of etoposide as positive control ($IC_{50}$: 20 ${\mu}M$). In A549 cell line, 5 and 6 showed cytotoxicities ($IC_{50}$: 4 ${\mu}M$ and 3 ${\mu}M$, respectively, with $IC_{50}$ of camptothecin as positive control: 10.3 ${\mu}M$). In the HepG2 cell line, 3, 5 and 7 showed cytotoxicity ($IC_{50}$: 4, 3 and 4 ${\mu}M$, respectively, with $IC_{50}$ of camptothecin: 0.3 ${\mu}M$). Compounds 6, 12 and 23 showed cytotoxicities in the HT-29 cell line ($IC_{50}$: 19, 19 and 15 ${\mu}M$, respectively, with $IC_{50}$ of camptothecin: 2 ${\mu}M$).
Control Method for Grid-Connected/Islanding Switching of Hybrid AC/DC Microgrid
Qu Zheng-Wei,Chong Zhen-Xiao,Wang Yun-Jing,Shi Zhe,Yao Yun-Xiao 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.1
For hybrid AC/DC microgrid (HMG) under master–slave control strategy, DGs usually adopt constant power control (P control) in gird-connected mode and at least one DG adopts constant voltage control (V control) in islanding mode. However, when unplanned islanding happens, the voltage and current of the HMG will experience remarkable fluctuations, which affects the system’s stability. This paper presents a control method to achieve smooth switching from grid-connected to islanding mode by introducing state tracking control between P control and V control. The state tracking control can make the current reference signal of the V control track that of the P control in grid-connected mode. When unplanned islanding happens, the mutation of the current reference signal can be tuned into a smooth transition by the voltage loop’s PI controller, and the transient oscillations can be eliminated to realize smooth switching. The effectiveness of the proposed control method is verified by simulation results using MATLAB/Simulink.
Three-Dimensional Elastic Stress Fields of Finite Thickness Plates with Elliptical Hole
Yang, Zheng,Cho, Chong Du,Su, Ting Ya,Kim, Chang Boo,Beom, Hyeon Gyu Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.353 No.-
<P>Based on detailed three-dimensional finite element analyses, elastic stress and strain field of ellipse major axis end in plates with different thickness and ellipse configurations subjected to uniaxial tension have been investigated. The plate thickness and ellipse configuration have obvious effects on the stress concentration factor, which is higher in finite thickness plates than in plane stress and plane strain cases. The out-of-plane stress constraint factor tends the maximum on the mid-plane and approaches to zero on the free plane. Stress concentration factors distribute ununiformly through the plate thickness, the value and location of maximum stress concentration factor depend on the plate thickness and the ellipse configurations. Both stress concentration factor in the middle plane and the maximum stress concentration factor are greater than that under plane stress or plane strain states, so it is unsafe to suppose a tensioned plate with finite thickness as one undergone plane stress or plane strain. For the sharper notch, the influence of three-dimensional stress state on the SCF must be considered.</P>
Jia Zheng,Chong-De Wu,Jun Huang,Rong-Qing Zhou,Xue Pin Liao 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.3
The volatile compounds in Chinese soy sauce moromi cultured by different fermentation processes [lowsalt solid-state fermentation (LSSF), high-salt dilute-state fermentation (HSDF), and high-salt constant temperature fermentation (HSCT)] were determined by GC-MS. The LSSF moromi had the highest total concentration of volatile compounds, followed by HSCT and HSDF moromi. Volatiles such as ethyl linoleate and ethyl oleate dominated in HSCT moromi. 2,3-Butanediol and 2,6-dimethylpyrazine were present at high content in LSSF moromi. The hierarchal cluster analysis (HCA) and principal component analysis (PCA) were employed to investigate the fermentation process effect on the category of samples. Based on HCA,HSCT (a1 and a2) and HSDF (b1 and b2) clustered in 1group, and LSSF (c1 and c2) located in another group. PCA illustrated that each kind of samples correlating with specific volatile compound groups were clearly differentiated according to their fermentation processes. The results suggest that GC-MS together with multivariate analyses could provide practical reference to recognize different Chinese soy sauces moromi.
GPU-ACCELERATED SPECKLE MASKING RECONSTRUCTION ALGORITHM FOR HIGH-RESOLUTION SOLAR IMAGES
Yanfang Zheng,Xuebao Li,Huifeng Tian,Qiliang Zhang,Chong Su,Lingyi Shi,Ta Zhou 한국천문학회 2018 Journal of The Korean Astronomical Society Vol.51 No.3
The near real-time speckle masking reconstruction technique has been developed to accelerate the processing of solar images to achieve high resolutions for ground-based solar telescopes. However, the reconstruction of solar subimages in such a speckle reconstruction is very time-consuming. We design and implement a new parallel speckle masking reconstruction algorithm based on the Compute Unified Device Architecture (CUDA) on General Purpose Graphics Processing Units (GPGPU). Tests are performed to validate the correctness of our program on NVIDIA GPGPU. Details of several parallel reconstruction steps are presented, and the parallel implementation between various modules shows a significant speed increase compared to the previous serial implementations. In addition, we present a comparison of runtimes across serial programs, the OpenMP-based method, and the new parallel method. The new parallel method shows a clear advantage for large scale data processing, and a speedup of around 9 to 10 is achieved in reconstructing one solar subimage of 256$\times$256 pixels. The speedup performance of the new parallel method exceeds that of OpenMP-based method overall. We conclude that the new parallel method would be of value, and contribute to real-time reconstruction of an entire solar image.
Single-Phase Virtual Synchronous Generator for Distributed Energy Resources Integration
Zeng, Zheng,Cheng, Chong,Tang, Shengqing,Yang, Huan,Zhao, Rongxiang Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.3
Virtual synchronous generator (VSG) in single-phase to interface distributed renewable energy resources is investigated in this paper. Mathematical models and numerical analysis are utilized to illustrate the features of the VSG. Enhanced control strategy is presented to ensure the performance of the VSG. Besides, a second order generalized integer (SOGI) is employed to calculate the instantaneous output power of the VSG in virtual ${\alpha}{\beta}$ frame. By the means of a phase-locked loop based scheme, the VSG can seamlessly transform between islanded and grid-tied modes, which can meet the requirements of micro-grid. At last, the validation and the proposed approach are verified by the simulated results using PSCAD/EMTDC.