영상 기반 자율경로주행을 위한 관심 영역 기반 End-to-End 심층 학습

장인식(Insik Jang),정은지(Eunji Jeong),이헌철(Heoncheol Lee) 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.2

본 논문은 영상 기반 End-to-End 자율경로주행 시스템에 대해 다룬다. Robot Operation System (ROS) 기반의 소형 주행 로봇을 이용하여 시스템을 구축하였고, 적용된 심층학습 모델은 AlexNet 이었다. 단안 카메라로부터 획득된 영상데이터와 사용자가 입력한 키보드 이벤트의 주행 방향 데이터를 이용하여 학습을 수행하였다. 영상 기반 End-to-End 자율경로주행의 성능 향상을 위해 관심 영역(Region of Interest, ROI)을 설정하면서 학습 및 추론 과정을 수행하였다. 실험 결과를 통해 본 연구에서 개발된 시스템이 별도의 고전적 영상처리 기법의 도움 없이 영상 기반 End-to-End 자율경로주행을 성공적으로 수행할 수 있음을 확인하였다.

무치악에 대한 최소 임플란트 구조물의 3차원 유한요소 해석

장인식(Insik Jang) Korean Society for Precision Engineering 2008 한국정밀공학회지 Vol.25 No.2

The aim of the study is to interpret the distribution of occlusal force by 3-dimensional finite element analysis of ISP(Implant Supported Prosthesis) supported by minimum number of implant to restore the edentulous patients. For this study, the Astra Tech implant system is used. Geometric modeling for 6 and 4 fixture ISP group is performed with respect to the bone, implant and one piece superstructure, respectively. Implants are arbitrarily placed according to the anatomical limit of lower jaw and for the favorable distribution of occlusal force, which is applied at the end of cantilever extension of ISP with 30㎜. Element type is tetrahedral for finite element model and the typical mechanical properties, Young's modulus and Poisson's ratio of each material, cortical, cancellous bone and implant material are utilized for the finite element analysis. From this study, we can see the distribution of equivalent stress equal to real situation and speculate the difference in the stress distribution in the whole model and at each implant fixture, From the analysis, the area of maximum stress is distributed on distal contact area between bone and fixture in the crestal bone. The maximum stress is 53㎫ at the 0.2㎜ area from the bone-implant interface in the maximum side for 300N load condition for 4 fixture case, which is slightly less than the stress calculated from allowable strain. This stress has not been deduced to directly cause the loss of crestal bone around implant fixture, but the stress can be much reduced as the old peoples may have lower chewing force. Thus, clinical trial may be performed with this treatment protocol to use 4 fixtured ISP for old patients.

상용승용차 시트프레임 부품의 중량 최적화에 관한 연구

장인식(Insik Jang),민병조(Byeong Jo Min) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.5

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code (ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool (CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame.Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.

차체의 변형형상과 변형정도에 의한 자동차 충돌상황의 재구성

장인식(Insik Jang),채덕병(Deokbyoung Chae) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.1

Collision accident reconstruction algorithms are developed based on the deformation shape and severity of a car body. At first, the body stiffness equation representing the force-deformation relationship is derived using finite element analysis for head on collision of two cars. The database of deformation shapes and energies is constructed for five different collision configurations; each configuration contains three velocity conditions. Deformation shapes are obtained using a curve fitting method and result in cubic polynomials. Deformation energies are calculated using a stiffness equation and deformation data. Three algorithms are developed to reconstruct collision configuration compared with constructed database. The developed algorithms show reasonably good performance to find collisions conditions for some test problems.

자동차 충돌해석에 의한 단순화된 차체 강성 방정식의 유도

장인식(Insik Jang),채덕병(Deokbyoung Chae) 한국자동차공학회 2000 한국 자동차공학회논문집 Vol.8 No.4

The deformation characteristics is one of the major factors to resume the crash configuration in collision accident reconstruction. Crash analysis are carried out using finite element method and body stiffness equations representing force-deformation relationship are derived. Two different crash conditions: 1) frontal barrier impact, 2) frontal impact between cars, are given for the derivation of the equations. The stiffness coefficient of equation by method 2) is larger than that by method I). Crash analysis between two vehicles is accomplished with three crash angles and three velocities for each angle condition. The deformations are measured for six selected points and deformation energies are calculated using the derived equations. Equation by method 2) results in better estimation of deformation energy than that by method I). for all crush configurations. The estimated energies can be utilized as one of indices to identify the type of the collision accident result.

차체간의 충돌상황에 따른 변형상태와 변형에너지와 관계

장인식(Insik Jang),이상묵(Sangmook Lee) 한국자동차공학회 1999 한국 자동차공학회논문집 Vol.7 No.3

A methodology for calcolating deformation energy is developed from deformed shape of a car after collision accident. Various crash configurations are established and analyzed using finite element method. The geometric model of a domestic car is made and meshes are ge-neratde by preprocessor, and the analyses are carried out using LS-DYNA3D. At first, two equivalent models are developed by substituting shell elements to beam elements and mass elements for the reduction of computation time. The mass equivalent model shortened the computation time by about 40 percentages. Force-deformation relationship is found from barrier impact test; which resulted in piecewise linear characteristics. Deformation energies are calculated from two-dimensional deformation shapes for eight collision cases. The energy may be utilized for estimation of velocity difference in accident reconstruction.<br/>

여러 가지 충돌 상황에 따른 FRP 어선 간의 충돌 해석

장인식(Insik Jang),김용섭(Yongseop Kim),김일동(Ildong Kim) 한국해양환경·에너지학회 2006 한국해양환경·에너지학회지 Vol.9 No.4

모드 주파수를 이용한 모델 개선 과정에 대한 연구

장인식(Insik Jang) Korean Society for Precision Engineering 2010 한국정밀공학회지 Vol.27 No.2

It is important to make a mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structure dynamics. In finite element analysis model updating is appropriate as the design parameter is used to analyze the dynamic system. The errors can be contained from the physical parameters and the element modeling. From the dynamic test, more precise dynamic characteristics can be obtained. In this paper, model updating algorithm is developed using frequency difference between experiment and calculation. Modal frequencies are obtained by experiment and finite element analysis for beams with various cross section and shapes which have added masses and holes in the middle. For plates with and without groove, experiment and analyses are carried out by applying free boundary conditions as well. Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies in case that both matrices are updated. An improved analytical model is obtained by changing model parameters such that the discrepancy between test and finite element frequencies is minimized. For beam and plate models updating of mass and stiffness matrices can improve the dynamical behavior of the model by acting on the physical parameters such as masses and stiffness.

3차원 충돌해석 정보를 이용한 측면 충돌 사고 재구성

장인식(Insik Jang),김일동(Ildong Kim) 한국자동차공학회 2008 한국 자동차공학회논문집 Vol.16 No.1

The side collision reconstruction algorithm is developed using three dimensional car crash analysis. Medium size passenger car is modeled for finite element analysis. Total 24 side collision configurations, four different speed and six different angle, are set up for making side collision database. Deformation index and degree index are built up for each collision case. Deformation index is a kind of deformation estimate averaging displacement of side door of crashed car from finite element analysis result. Angle index is constructed measuring deformed angle of crashing car. There are two kinds of angle index, one is measured at driver's side and the other is measured at passenger's side. Also a collision analysis information in side of cars is used for giving a basis for scientific and practical reason in a reconstruction of the car accident. The analysis program, LS-DYNA3D is utilized for finite element analysis program for a collision analysis. Those database are used for side collision reconstruction. Side collision reconstruction algorithm is developed, and applied to find the collision conditions before the accident occurs. Three example collision cases are tried to check the effectiveness of the algorithm. Deformation index and angle index is extracted for the case from the analysis result. Deformation index is compared to the established database, and estimated collision speed and angle are introduced by interpolation function. Angle index is used to select a specific collision condition from the several available conditions. The collision condition found by reconstruction algorithm shows good match with original condition within 10% error for speed and angle. As a result, the calculation from the reconstruction of the situation is reproducing the situation well. The performance in this study can be used in many ways for practical field using deformation index and degree index. Other different collision situations may be set up for extending the scope of this study in the future.

복합 목적의 제어 망을 위한 보안 네트워크 설계

장인식(InSik Jang),이재용(JaeYong Lee),김병철(ByungChul Kim),이명신(MyungShin Lee),현대환(DaeHwan Hyun),박세철(SeChul Park),정대원(DaeWon Chung) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.2