Exploring Mobility-Based O2O Business Success : A Cross-Country Study on Ride Hailing and Car Sharing Services

Jaewon Seol,Dongwon Lee 한국경영정보학회 2020 한국경영정보학회 학술대회논문집 Vol.2020 No.12

하모닉 감속기 웨이브 제너레이터 베어링의 하중 발생 메커니즘 연구

이설(Seol Lee),김경준(Kyung Jun Kim),윤신(Seen Yun),원홍인(Hong-In Won),김재원(Jaewon Kim),이동주(Dong Ju Lee),신상윤(Sang Yun Shin),정진태(Jintai Chung) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.4

다변량 LSTM을 이용한 극저온 액화가스 저장탱크의 슬로싱에 의한 첨두 압력 예측

김재원(Jaewon Kim),정소명(Somyung Chung),전규목(Gyumok Jeon),박종천(Jongchun Park) 한국해양환경·에너지학회 2021 한국해양환경·에너지학회 학술대회논문집 Vol.2021 No.10

본 연구에서는 극저온 액화가스 저장 탱크 내부에서 발생하는 슬로싱에 의한 탱크 내부의 첨두 압력을 계산하기 위한 전산유체 시뮬레이션과, 시뮬레이션을 통한 계산값 이후의 첨두 압력 시계열 결과값 예측을 위해 딥러닝 방식의 순환 신경망 구조(Recurrent Neural Network, RNN) 중 하나인 LSTM(Long Short-Term Memory)를 이용하는 방법론을 제시한다. 극저온 액화가스 저장탱크의 첨두 압력 계산을 위한 상용 유동해석 시뮬레이션 프로그램으로 STAR-CCM+(ver. 15.02.007)을 사용하였으며, 계산된 첨두 압력 시계열을 Python 기반 Tensorflow 라이브러리의 LSTM 모델을 통해 이후 시계열 값을 예측하였다. 이 때 저장탱크 내 첨두 압력 시계열에 직접적인 영향을 미치는 것으로 판단되는 변수를 다변량으로 LSTM 모델에 포함시켜 계산을 진행하였으며, 이를 시뮬레이션 계산 결과와 비교하여 LSTM을 통한 예측값의 유효성을 판단하였다. This study presents a methodology of using LSTM(Long Short-Term Memory), one of the deep learning Recurrent Neural Networks(RNN), to calculate peak pressure inside the cryogenic storage tank by sloshing generated inside the tank and predict peak pressure time series after calculation. STAR-CCM+(ver.15.02.007) was used in this study for calculation of peak pressure in the tank, and LSTM module in Tensorflow(ver.2.4.0) based Python was used in this study for prediction of time series after calculations. Then the calculation was performed by including variables that were determined to have a direct effect on the peak pressure time series in the storage tank in a Multivariate LSTM, and the validity of the predicted value through LSTM was determined by comparing them with the simulation and calculation results.

Effect of Keratin-Based Biocomposite Hydrogels as a RhBMP-2 Carrier in Calvarial Bone Defects Mouse Model

Jongjin Lee,Jinsu Kang,Jaewon Seol,Nam-soo Kim,허수영 한국임상수의학회 2022 한국임상수의학회지 Vol.39 No.6

Recently, in human medicine and veterinary medicine, interest in syn- thetic bone graft is increasing. Among them, bone morphogenic protein (BMP) is currently being actively researched and applied to clinical trials. However, BMP has the disadvantage of being expensive and easily absorbed into surrounding tissues. Therefore, BMP requires the use of small amounts and rhBMP (recombi- nant human bone morphogenetic protein)-2 carriers that can be released slowly. Hydrogel has the property of swelling a large amount of water inside when it is aqueous solution, and when it is, it consists of more than 90 percent water. Using these properties, hydrogels are often used as rhBMP-2 carrier. The scaffold used in this study is a hydrogel made from which keratin is extracted using hu- man hair and based on it. In this study, we wanted to see the effect of bone for- mation in the calvarial defect model by using keratin-based hydrogel made with human hair as a scaffold. The experiment was conducted by dividing 3 groups a total of 12 mice. Calvarial bone defect is set to all 4 mm diameters. Bone for- mation was evaluated by using gross evaluation, micro-computed tomography (micro-CT), immunohistochemistry. Groups using keratin-based hydrogel were significantly observed compared to Group 1s, and the most bone formations were found when rhBMP-2 and hydrogel were used. This represents the supe- riority of the functions of the rhBMP-2 carrier by a new material, keratin-based hydrogel. Through gross evaluation, micro-CT, and immunohistochemistry, we can confirm that keratin-based hydrogel is a useful rhBMP-2 carrier.

Principle of restoration ecology reflected in the process creating the National Institute of Ecology

Kim, A. Reum,Lim, Bong Soon,Seol, Jaewon,Lee, Chang Seok The Ecological Society of Korea 2021 Journal of Ecology and Environment Vol.45 No.3

Background: The creation of the National Institute of Ecology began as a national alternative project to preserve mudflats instead of constructing the industrial complexes by reclamation, and achieve regional development. On the other hand, at the national level, the research institute for ecology was needed to cope with the worsening conditions for maintaining biodiversity due to accelerated climate change such as global warming and increased demand for development. In order to meet these needs, the National Institute of Ecology has the following objectives: (1) carries out studies for ecosystem change due to climate change and biodiversity conservation, (2) performs ecological education to the public through exhibition of various ecosystem models, and (3) promotes regional development through the ecological industry. Furthermore, to achieve these objectives, the National Institute of Ecology thoroughly followed the basic principles of ecology, especially restoration ecology, in the process of its construction. We introduce the principles and cases of ecological restoration applied in the process. Results: We minimized the impact on the ecosystem in order to harmonize with the surrounding environment in all the processes of construction. We pursued passive restoration following the principle of ecological restoration as a process of assisting the recovery of an ecosystem degraded for all the space except in land where artificial facilities were introduced. Reference information was applied thoroughly in the process of active restoration to create biome around the world, Korean peninsula forests, and wetland ecosystems. In order to realize true restoration, we pursued the ecological restoration in a landscape level as the follows. We moved the local road 6 and high-voltage power lines to underground to ensure ecological connectivity within the National Institute of Ecology campus. To enhance ecological diversity, we introduced perch poles and islands as well as floating leaved, emerged, wetland, and riparian plants in wetlands and mantle communities around the forests of the Korean Peninsula in the terrestrial ecosystem. Furthermore, in order to make the public aware of the importance of the intact nature, the low-lying landscape elements, which have disappeared due to excessive land use in most areas of Korea, was created by imitating demilitarized zone (DMZ) landscape that has these landscape elements. Conclusions: The National Institute of Ecology was created in an eco-friendly way by thoroughly reflecting the principles of ecology to suit its status and thus the impact on the existing ecosystem was minimized. This concept was also designed to be reflected in the process of operation. The results have become real, and a result of analysis on carbon budget analysis is approaching the carbon neutrality.

한국 하천의 구간 별 특성과 생태적 복원을 실현하기 위한 대조식생 정보

정성희 ( Jung Song Hie ),김아름 ( Kim Areum ),설재원 ( Seol Jaewon ),임봉순 ( Lim Bong Soon ),이창석 ( Lee Chang Seok ) 한국물환경학회(구 한국수질보전학회) 2018 한국물환경학회지 Vol.34 No.5

To realize river restoration that ecological characteristics of the river are reflected, we classified the river into four reaches of valley stream, upstream, midstream, and downstream based on substrate as well as riverbed gradient obtained from the relationship between distance from the river mouth, and above sea level. Considering that the rivers of Korea have been dominated by various and intense artificial interferences over a lengthy period, we determined cross sectional range of the river based on the geological map and clarified transformation degree by reach. Vegetation profile diagram was prepared by depicting horizontal range and vertical stratification of major vegetation appearing in a belt transect of 10 m breadth installed between weirs constructed in both sides of the river. Restoration models by river reach were prepared based on breadth of waterway, bare ground, herb, shrub, and tree dominated vegetation zones on vegetation profiles wherein a flooding regime was reflected. Species composition information collected from vegetation established in each zone was systematized to use for restoring each reach ecologically. Further, background that longitudinal reaches and horizontal zones were divided, was discussed by comparing with case studies in foreign countries. In addition, necessity of ecological restoration of the river was discussed based on degree of integrity of Korean rivers, ecological significance of riparian vegetation, and importance of reference information for ecological restoration of the river.

인공신경망을 이용한 고장 심각도에 따른 무인기용 유성감속기의 고장진단 연구

박형준(Hyung Jun Park),심진우(Jinwoo Sim),장재원(Jaewon Jang),장경환(Kyung-Hwan Jang),설진운(Jin-Woon Seol),권준용(Jun-Yong Kwon),최주호(Joo-Ho Choi) 한국신뢰성학회 2021 신뢰성응용연구 Vol.21 No.4

Purpose: Gear teeth in the rotary geared actuator of the unmanned aerial vehicle, experience crack propagation because of its harsh operating conditions. To prevent the failure of catastrophic events, this study proposes a diagnostic approach for various gear crack levels based on the built-in and add-on sensor signal. Methods: A downsized planetary gearbox test rig was prepared, in which the motor position, current, and vibration signals were acquired for the normal and 4 different crack-induced states. Signals were filtered around the region of resonance frequencies by spectral kurtosis and the features for the health state were extracted. Then, feature selection was conducted based on the correlation with fault levels. Finally, the Artificial Neural Network (ANN) model was constructed to identify different fault sizes of the cracks, and K-fold validation was adopted to optimize the parameters of the ANN model. Results: Among the various signals, the vibration from the add-on sensor and a position from the built-in sensor exhibited high performance compared to the current signal. The features after band-pass filtering yielded a high correlation with fault severity. Conclusion: The proposed method successfully diagnosed different fault severities of gear cracks in the planetary gearbox by using both the built-in and add-on signals.

Elevated TRAF2/6 expression in Parkinson's disease is caused by the loss of Parkin E3 ligase activity.

Chung, Ji-Yun,Park, Hee Ra,Lee, Su-Jin,Lee, Sun-Hye,Kim, Jin Sik,Jung, Youn-Sang,Hwang, Sang Hyun,Ha, Nam-Chul,Seol, Won-Gi,Lee, Jaewon,Park, Bum-Joon United States and Canadian Academy of Pathology [e 2013 Laboratory investigation Vol.93 No.6

<P>Parkinson's disease (PD) is the second leading neurodegenerative disease, and is known to be induced by environmental factors or genetic mutations. Among the verified genetic mutations of PD, Parkin, isolated from the PARK2 locus, shows an autosomal recessive inheritance pattern and is known to be an E3 ligase. However, the physiological target of Parkin and the molecular mechanism of Parkin-deficiency-induced PD have not been clearly demonstrated until now. It has recently been proposed that inflammation, suggesting as a causal factor for PD, is enhanced by Parkin deficiency. Thus, we examined the relationship between inflammation-related factors and Parkin. Here, we provide the evidence that Parkin suppresses inflammation and cytokine-induced cell death by promoting the proteasomal degradation of TRAF2/6 (TNF-α receptor-associated factor 2/6). Overexpression of Parkin can reduce the half-lives of TRAF2 and TRAF6, whereas si-Parkin can extend them. However, mutant Parkins did not alter the expression of TRAF2/6. Thus, loss of Parkin enhances sensitivity to TNF-α- or IL-1β-induced JNK activation and NF-κB activation. Indeed, si-Parkin-induced apoptosis is suppressed by the knockdown of TRAF6 or TRAF2. We also observed elevated expression levels of TRAF6 and a reduction of IκB in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD mouse model. Moreover, elevated expression levels or aggregation of TRAF6 were detected in approximately half of the human PD tissues (7/15 cases) and 2 cases, respectively. In addition, TRAF6 and Parkin expression levels show a reverse relationship in human PD tissues. Our results strongly suggest that the reduction of Parkin or overexpression of TRAF2/6 by chronic inflammation would be the reason for occurrence of PD.</P>