http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
수직 주차에서 AVM을 이용한 동시적 위치추정 및 지도 생성
안찬우(Chanwoo Ahn),박재흥(Jaeheung Park) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11
In this paper, we propose a Simultaeneous Localization And Mapping(SLAM) method for vertical parking scenario. Most commercial car uses ultrasonic sensor to localize vehicle’s position in parking lot. However, vehicle cannot be localized when there are not any obstacles around ego vehicle. The proposed method uses simple features from parking lines and localizes vehicle’s position without any assumption about obstacles around ego vehicle using only Around View Monitor(AVM). At first, cross point is proposed as a feature which can be used for tracking. Cross points on parking lines are detected using Deep Learning and parking lines are extracted using RANSAC and Canny Edge. Using detected cross points and parking lines, relative poses between frames are tracked using Iterative Closeset Point(ICP) and landmark based localization. Global position of detected cross point is used as landmark’s position and position of intersection from detected lines is used as local position of the corresponding cross point. Using landmark based localization, relative poses are calculated and accumulated errors are recovered. From above method, we build a 2D map which is continuously optimized. We evaluated our proposed approach on our own dataset and compared our result with LOAM(Lidar Odometry and Mapping in Real-time).
Chanwoo Park,Namin Koo,Jino Kwon,Joo-Hoon Lim,Yong-Ho Jeong,Jung-Ho Kim 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.1
This study was conducted to determine the changes in soil chemical properties and the growth of seedling according to the different dredged soil improving methods at slope of Saemangeum sea dike. Undersea dredged soil was improved by five different methods. Seedlings of Ulmus davidiana var. japonica, Chionanthus retusa, Celtis sinensis, and Pinus thunbergii were planted after 9 month of experience site installation, then soil pH, NaCl concentration in soil, soil organic matter (SOM), and survival rate and height of seedling was measured. Initial soil pH was highest in the control plot but it decreased to the similar level with other soil improving plots after 35 months. There were no differences in NaCl concentration between the control and soil improving plots, and it showed decreasing tendency during the study period. In the control plot, initial SOM was lowest among that of other plots during the study period. The survival rate of 36 months after planting of P. thunbergii was highest among the species. The gap of the tree growth of P. thunbergii between the control plot and the soil improving plots was small, however, other species showed relatively higher tree height in the soil improving plots than the control plots. Creation forest with P. thunbergii might be a cost effective afforestation in coastal reclaimed land since it rarely needs additional improvement of dredged soil.
Park, Chanwoo,Koo, Namin,Kwon, Jino,Lim, Joo-Hoon,Jeong, Yong-Ho,Kim, Jung-Ho 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.1
This study was conducted to determine the changes in soil chemical properties and the growth of seedling according to the different dredged soil improving methods at slope of Saemangeum sea dike. Undersea dredged soil was improved by five different methods. Seedlings of Ulmus davidiana var. japonica, Chionanthus retusa, Celtis sinensis, and Pinus thunbergii were planted after 9 month of experience site installation, then soil pH, NaCl concentration in soil, soil organic matter (SOM), and survival rate and height of seedling was measured. Initial soil pH was highest in the control plot but it decreased to the similar level with other soil improving plots after 35 months. There were no differences in NaCl concentration between the control and soil improving plots, and it showed decreasing tendency during the study period. In the control plot, initial SOM was lowest among that of other plots during the study period. The survival rate of 36 months after planting of P. thunbergii was highest among the species. The gap of the tree growth of P. thunbergii between the control plot and the soil improving plots was small, however, other species showed relatively higher tree height in the soil improving plots than the control plots. Creation forest with P. thunbergii might be a cost effective afforestation in coastal reclaimed land since it rarely needs additional improvement of dredged soil.
Chanwoo Park,Chang-Yeol Joh,Young-Sang Kim 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.2
In this study, the optimization of an aircraft wing design was conducted using multidisciplinary design optimization (MDO), which integrates aerodynamic and structural analysis in considering nonlinear structural behavior. Automation is an absolute necessity to make the MDO framework practical for actual engineering optimization problems. The objective of this research was to develop a fully automated MDO framework in which the entire process is automated through a parametric-modeling approach. The computational fluid dynamics (CFD) grid was generated automatically from parametric modeling using CATIA and Gridgen, followed by automatic flow analysis using FLUENT. The computational structure mechanics (CSM) grid was generated automatically by the parametric methods of CATIA and MSC/Patran. The structure was analyzed by ABAQUS considering the deformation nonlinearity, and the aerodynamic load was transferred from the CFD grid to the CSM grid using the volume spline method. The response Surface method was applied for optimization, which helped achieve the global optimum. The developed MDO framework was applied to a wing optimization problem in which the objective was wing weight and the constraints were the lift-drag ratio, wing deflection, and structural stress level. The aspect ratio, taper ratio, quarter-chord sweep angle, skin thickness, and spar flange area were the design variables. The optimization design result demonstrated a successful application of the fully automatic MDO framework.
Interface Resistance Switching Characteristics of Metal/Nb-Doped SrTiO3 Junctions
Chanwoo Park,김동욱 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I
We report on the transport properties of junctions consisting of metal electrodes (M = Ti, Ni, and Pt) and (001)-oriented Nb-doped SrTiO$_3$ (Nb:STO) single crystals. The junctions with M = Ti, which had a shallow work function, exhibited linear current-voltage ($I$-$V$) characteristics without hysteresis. For M = Ni and Pt, with a large work function, the junctions showed rectifying $I$-$V$ characteristics and notable hysteresis upon polarity reversal. The resistance change ratio for M = Ni (Pt) did (not) depend on the doping ratio of Nb:STO. This clearly suggests that the metal work function may not be sufficient to explain the resistance switching.
Park, Chanwoo,Jiang, Nan,Park, Taesung Korea Genome Organization 2019 Genomics & informatics Vol.17 No.4
The achievements of genome-wide association studies have suggested ways to predict diseases, such as type 2 diabetes (T2D), using single-nucleotide polymorphisms (SNPs). Most T2D risk prediction models have used SNPs in combination with demographic variables. However, it is difficult to evaluate the pure additive contribution of genetic variants to classically used demographic models. Since prediction models include some heritable traits, such as body mass index, the contribution of SNPs using unmatched case-control samples may be underestimated. In this article, we propose a method that uses propensity score matching to avoid underestimation by matching case and control samples, thereby determining the pure additive contribution of SNPs. To illustrate the proposed propensity score matching method, we used SNP data from the Korea Association Resources project and reported SNPs from the genome-wide association study catalog. We selected various SNP sets via stepwise logistic regression (SLR), least absolute shrinkage and selection operator (LASSO), and the elastic-net (EN) algorithm. Using these SNP sets, we made predictions using SLR, LASSO, and EN as logistic regression modeling techniques. The accuracy of the predictions was compared in terms of area under the receiver operating characteristic curve (AUC). The contribution of SNPs to T2D was evaluated by the difference in the AUC between models using only demographic variables and models that included the SNPs. The largest difference among our models showed that the AUC of the model using genetic variants with demographic variables could be 0.107 higher than that of the corresponding model using only demographic variables.