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디젤엔진의 DPF 재생 시 입자상 물질의 크기 분포 및 개수 특성
김동수(Dongsu Kim),이정우(Jeongwoo Lee),이준용(Junyong Lee),이승하(Seungha Lee),이승현(Seunghyun Lee),이정연(Jungyeon Lee),이윤우(Yoonwoo Lee),최회명(Hoimyung Choi),민경덕(Kyungdoug Min) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
EGR is a promising technique to meet the demand of stringent emission regulations. For example, the new upcoming emissions regulation, EURO 6, requires reduction of NOx emissions by 55% while maintaining the same level of PM emissions. However, reducing NOx emissions by applying a higher EGR rate inevitably yields higher PM emissions due to NOx-PM trade-off relationship. Hence, increased PM emissions caused by the use of higher EGR rate lead to more frequent DPF regeneration. Therefore, it is necessary to have a look at emission characteristics during the regeneration event. However, most of recent studies focus on downstream emissions of after-treatment system. Thus, in this research, not only the distribution of downstream PM particle size is studied but also the distribution of upstream PM particle size is investigated so that future strategies and data for DPF regeneration can be established. In general, DPF regeneration is favored at high speed and load conditions.
Dongsu Lee,Seungho Lee,Jong-Wook Kim,Cheol-Gyun Lee,Sang-Yong Jung IEEE 2011 IEEE transactions on magnetics Vol.47 No.5
<P>Optimal design of an electric machine based on finite element analysis (FEA) calls for much longer computation time for maintaining high accuracy. In order to compensate for the excessive computation time and guarantee the reliable convergence to a global optimum, an intelligent memetic algorithm is newly implemented by combining a genetic algorithm (GA) and the guided mesh adaptive direct search (MADS) that employs an extension search step after the poll step. The effectiveness of guided MADS (GMADS) alone has been verified through the function optimization, and the proposed memetic algorithm is applied to an optimal design of an interior permanent magnet synchronous machine (IPMSM), of which the cost function has many local minima. Optimization results confirm that the proposed method locates an acceptable solution more effectively maintaining the reliable accuracy.</P>
Research on Deep learning based black ice and pothole detection in edge-devices
Dongsu Lee,Seungmin Oh,Jihoon Lee,Yeonggwang Kim,Sangjoon Lee 한국디지털콘텐츠학회 2020 The Journal of Contents Computing Vol.2 No.2
Research on the detection of dangerous areas such as potholes and black ice, which can cause traffic accidents on roads and bridges, helps maintain faster and smoother traffic flow and is essentially essential in protecting the lives and property of drivers and pedestrians. In this dissertation, we propose a deep learning model that can detect dangerous regions such as potholes and black ice. To learn and evaluate the proposed deep learning model, we collect 806 images for pothole detection, 1,000 images for black ice detection. Subjectively/objectively evaluating the performance of the proposed deep learning model, we derive 95% accuracy for pothole detection and 79% accuracy for black ice detection. This study was limited to not being able to practice in real-time road driving situations, and the next study is to implement real-time output of the results with respect to the hazardous areas detected by the camera. This will also be used for research related to smart factories, smart cities and eco-friendly cars that require hard real-time such as traffic control systems, airport control systems, and satellite launch control systems in the future.
미세먼지로 인한 온실 피복재 투과율 저하 실험모델 개발
이종혁 ( Jonghyuk Lee ),정영준 ( Youngjoon Jeong ),이상익 ( Sangik Lee ),서병훈 ( Byunghun Seo ),김동수 ( Dongsu Kim ),홍은미 ( Eunmi Hong ),이승재 ( Seungjae Lee ),이재한 ( Jaehan Lee ),최원 ( Won Choi ) 한국농공학회 2020 한국농공학회 학술대회초록집 Vol.2020 No.-
최근 국내외로 급속한 산업화로 인해 황사 및 미세먼지 발생 횟수가 증가하고 있으며, 이러한 미세먼지는 비닐온실의 투과율을 저하시켜 시설 작물의 생육 환경을 저해한다. 본 연구에서는 미세먼지 발생으로 인한 온실 피복재 투과율 저하도를 구명하고, 온습도 환경에 따른 미세먼지 흡착율을 평가하기 위해 축소실험모델을 개발하였다. 모델은 1개의 미세먼지 발생환경 재현 챔버와 미세먼지 발생장치, 온습도 및 미세먼지 측정 모니터링 센서를 포함한 컨트롤러로 구성되었다. 미세먼지 발생장치의 시료 투입구에 공압펌프를 활용하여 일정 간격으로 미세입자가 주입되며, 정량 투입을 위한 물리적 장치가 고안되었다. 또한 미세먼지 발생장치 내 싸이클론 발생기와 필터를 설치하여 챔버 내 미세먼지의 입경별 투입을 고려하였다. 미세먼지 시료는 입경 분포가 0.97 - 22.00 ㎛로 이루어진 Arizona test dust (A1 Ultrafine)을 사용하였으며, 온실 설계 시 가장 많이 활용되는 폴리에틸렌 (PE) 피복재를 대상으로 투과율 저하도를 분석하였다. 챔버내 온·습도 환경을 조절하며 미세먼지 흡착율에 따른 비닐시편의 투과율 저하도를 비교하였다.
압축착화 엔진에서 JP-8의 연소 및 배기 특성에 관한 연구
이정연(Jungyeon Lee),이정우(Jeongwoo Lee),이승현(Seunghyun Lee),김동수(Dongsu Kim),이승하(Seungha Lee),이철환(Cheolhwan Lee),민경덕(Kyoungdoug Min),최회명(Hoimyung Choi) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
In 1998, Single Fuel Concept was adopted by NATO nations for the purpose of using one fuel for the land based military aircrafts, vehicles and equipment. The reason behind such a decision was not because of management and logistic benefits. This decision was also for smooth engine operation in the battlefield. JP-8 which is kerosene type turbine fuel and containing several additives for the military purpose was selected as the single fuel. JP-8 is originally used in the combat aircrafts, but it can also be used in CI engines, as its basic characteristics are similar to that of a diesel fuel. Although there have been a lot of experiments and studies on the use of JP-8 on CI engines, more research on the JP-8 combustion on CI engine is required for a better understanding about of the combustion process and preventing air pollution. Thus, this present study attempts to find out the optimal operation conditions that have a similar or better engine performance and lower exhaust emissions compared to the conditions of diesel fuel combustion. This study evaluates the effects injection timing, injection pressure, boost pressure, EGR rates, and engine load on a four-cylinder CI engine containing JP-8 with displacement volume of 2.2L
Eun-Jin Lee,Hee-Jung Lee,Danny Oh,Jung-Youn Park,Dongsu Kim,Sang-Nam Lee,이기현,Ji-Yeon Lee,Kyeong Han Kim,Soo-Hyun Sung 대한약침학회 2022 Journal of pharmacopuncture Vol.25 No.1
Objectives: This study aims to develop a community care model in traditional Korean medicine (TKM) by developing a community care participation model for the health of the elderly and deriving tasks to implement it. Methods: This study implemented a group interview with experts. A fact-finding survey was conducted targeting 16 local governments that are implementing a leading project to identify the status of TKM service provision and welfare service linkage in all regions. An expert group interview (FGI) targeted public and private sector experts for each job role, the former represented by those in charge of the central government’s health care policy and administrative delivery system, and the latter by professors majoring in social welfare, professors majoring in health, and local TKM societies. After forming the expert groups, three expert group interviews were conducted. Results: Through collective interviews with experts, a model for providing TKM and welfare services in community integrated care was derived by dividing it into local and central government levels. The strategies and tasks for promoting TKM-oriented health welfare services were derived from 3 strategies, 8 tasks, and 20 detailed tasks. Conclusion: The core direction of the TKM health care model is the region-centered provision of TKM and welfare services. To this end, policy support for the use and linkage of health care service resources is required at the central government level, and linkage and provision of health welfare services centered on TKM are necessary through linkage and convergence between service subjects and between government health care projects.
Lee, Dongsu,Son, Byung Kwan,Kim, Jong-Wook,Jung, Sang-Yong The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.4
Optimizing the design of large-scale electric machines based on nonlinear finite element analysis (FEA) requires longer computation time than other applications of FEA, mainly due to the huge size of the machines. This paper addresses a new region decision method (RDM) with mesh adaptive direct search (MADS) for the optimal design of wind generators in order to reduce the computation time. The validity of the proposed algorithm is evaluated using Rastrigin and Goldstein-Price benchmark function. Moreover, the algorithm is employed for the optimal design of a 5.6MW interior permanent magnet synchronous generator to minimize the torque ripple. Additionally, mechanical stress analysis as well as electromagnetic field analysis have been implemented to prevent breakdown caused by large centrifugal forces of the modified design.
Lee, Dongsu,Hwang, Sujin korean Academy of Physical Therapy Rehabilitation 2019 Physical therapy rehabilitation science Vol.8 No.1
Objective: The purpose of this review was to investigate whether motor imagery training has an effect on the recovery of upper extremity function in individuals with hemiparetic stroke or not. Design: A systematic review and meta-analysis. Methods: PubMed and three other databases were searched up to December 18th, 2018 and randomized controlled trials (RCTs) evaluating motor imagery training on upper extremity function in persons with a diagnosis of hemiparetic stroke were included. This review selected the following information from each study: surname of the first author, published year, nation, population, intervention, therapeutic intensity of intervention, therapeutic comparison, outcome measures, additional therapy, summary of results, and descriptive statistics of outcome measures. Results: This review selected seventeen RCTs with 487 stroke survivors and the following intervention methods: six motor imagery training with additional therapeutic technology, two motor imagery training with additional modified constraint-induced therapy, four mirror therapy, and five motor imagery training. Ten RCTs were eligible for meta-analysis after systematic review. The motor imagery group were more effective than the control group based on the Fugl-Meyer assessment (3.43; 95% confidence interval [CI], 1.65 to 5.22; heterogeneity [$chi^2=8.03$, df=8, $I^2=0%$], test of overall effect Z=3.76; test for subgroup differences [$chi^2=2.56$, df=2, $I^2=21.8%$]) and the Action Research Arm Test (1.32; 95% CI, -8.12 to 10.76; heterogeneity [$Tau^2=70.74$, $chi^2=15.22$, df=3, $I^2=80%$], test of overall effect Z=3.76). Conclusions: The results of this review suggests that motor imagery shows positive effectiveness on improving upper extremity function in persons with hemiparetic stroke.