• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.93-94
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• 2016

친환경 이동수단 중 1인용 이동수단인 퍼스널 모빌리티에 대한 관심과 수요가 증대됨에 따라 과거 전기자전거에서 현재는 전동퀵보드, 전동스쿠터, 외발휠, 세그웨이류 등 그 종류와 외관적 형태는 매우 다양하다. 하지만 공통적인 부분은 전기에너지를 구동원으로 하고 있으며, 전기에너지를 저장하기 위한 수단으로 리튬이온 배터리가 사용된다는 것이다. 리튬이온배터리에서 배터리를 안전하고 효율적으로 사용하도록 제어하는 부분이 배터리관리시스템이며, 기능중에서 배터리 셀간을 정밀하게 균형을 잡아주며, 모든 셀이 완전 충전상태가 될 수 있도록 도와주는 셀 밸런싱 기능이 있다. 이러한 셀 밸런싱 기술은 주행거리 혹은 사용시간을 늘려주는 역할을 수행한다. 본 논문에서는 충전과 방전을 반복하는 다셀로 구성된 리튬이온배터리에서 셀 밸런싱이 수행되는 과정을 살펴보고 단일 밸런싱과 다중 밸런싱의 차이 및 장단점을 살펴보았다. 이를 통해 완속에서 급속충전으로의 변화, 빠른 셀 밸런싱 등의 필요성에 대해 실험을 통해 검증하였다.

• The Journal of Sustainable Design and Educational Environment Research
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• v.14 no.2
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• pp.26-36
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• 2015

The new town was assumed that there is a difference between the country's elementary school environment. First, given the important elements of the school safety plan in order to verify this, and we plan to set up each of these elements by safety criteria. In the second chapter in order to achieve the objective of this study was to develop indicators to evaluate the safety of the school environment influences the safety of the school environment through the theoretical consideration. In Chapter 3, the difference in safety through the new elementary school survey of metropolitan areas was given a score per item per item depending on the evaluation criteria. The fourth section is the difference between safety school environment can be summarized as the following analytical results that the difference between the new city. The results of this study as follows: First, the characteristics of the elementary school environment showed a significant difference between the new town. Second, school location, terrain characteristics, bike paths and pedestrian to the installation, the safety of landscape installations, installing median barriers, traffic safety facilities, speed bumps, separation of pedestrian and vehicle circulation in the front door, scores of elements of the plan such as parking scheme there is a difference between the new town. Third, the introduction of elements of the plan such as Traffic calming or Traffic Island installation techniques was found lacking.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.1-5
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• 2013

In order to evaluate fatigue endurance for an MTB(mountain bike) frame, FEM(finite element method) analysis was performed. For evaluating the fatigue endurance of the MTB frame, the S-N data for Al-6061 fillet weldment were compared with the stress analysis results through FEM analysis of the frame. Three loading condition, pedalling, horizontal and vertical loading conditions were considered for fatigue endurance evaluation. Horizontal loading(+1200 N) condition was found to be the most severe to the frame. The maximum von Mises stress of the frame under horizontal loading(+1200 N) condition was determined 294 MPa through FEM analysis of the frame. Conclusively, on the basis of fatigue strength of 200 MPa at the number of cycles of 50,000, the MTB frame has an improper safety factor of approximately 0.25, suggesting that this frame needs reinforcement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.223-233
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• 2014

This study empirically analyzes the relationships among the road and traffic experts' personal characteristics, the driving behavior and factors being expected to have an effect on the satisfaction about roundabout operation. The factors are drawn and grouped through the principle component analysis to clarify driving environment satisfaction on roundabout operation. Each group is named as personal attribute, driving behavior attribute, and satisfaction. After the variables are refined by confirmatory factor analysis, satisfaction model is developed with personal attribute and driving behavior attributes as exogenous variables and roundabout driving awareness and emotion attributes as endogenous variables. As a result, driving satisfaction of roundabout operation is directly influenced by delay reduction, safety improvement, capacity increase, sight improvement, severity accident reduction, and bicycle convenience and indirectly gender, age, driving time, and driving experience. Law obeyance, driving concession, traffic sign obeyance, and interposition do not statistically shows significant on satisfaction. As a result of Analytical Hierarchy Process (AHP), the turning radius of geometry and the driving behavior are important elements for roundabout safety.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.1-5
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• 2016

A bicycle is one of the most popular sporting goods in view of a sport activity and a human health. Metallic materials such as steel, aluminum, etc. were mainly used to the bicycle fork in the past. Nowadays, the carbon fiber reinforced composite materials are widely used to the manufacturing of a bicycle fork to reduce the weight and to increase the efficiency. Safety is a most important design parameter of a bicycle fork even if the weight and cost reduction are important. Bicycle failure may happen at the critical spot of a bicycle fork and cause the accident. In this paper, the composite bicycle fork will be analyzed to secure the safety and detect a critical spot by using the finite element method with Tsai-Wu failure criterion. The stress data were obtained for the laminated composites with various number of plies and fiber orientation under the bending load. Thus, design concept of a bicycle fork was proposed to secure the safety of a bicycle. The finite element analysis results show that the connection area between a steer tube and a fork blade is critical spot, and 75 or more layers of 0 degree are needed to secure the safety of a bicycle fork.

• Journal of Korean Society of Disaster and Security
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• v.14 no.3
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• pp.29-38
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• 2021

Riverfront facilities are river space facilities used by citizens for the rest and convenience. Recently, although the importance of efficient maintenance of riverfront facilities is increasing, damaging facilities cases are increasing due to frequent floods. Currently, the inspections and diagnosis of river space facilities are limited to the main flood control facilities. And the standards for the maintenance and management of the riverfront facilities are insufficient. Utilization survey, which is the standard for managing river space facilities, is also inefficient in terms of manpower consumption and economic feasibility. This study uses mobile big data to classify river usage and conducts a survey for usability of river facilities to derive economic evaluation for usage performance. In the future, if economical method system that considers safety, usability, and durability is conducted and demanding analysis for each convenience facility is evaluated, it is expected that the efficient maintenance of riverfront facilities is perfomed better and the use of rivers by citizens will further increase.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.95-111
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• 2021

As the population decreases in an aging society, the average age of drivers increases. Accordingly, the elderly at high risk of being in an accident need autonomous-driving vehicles. In order to secure driving safety on the road, several technologies to respond to various obstacles are required in those vehicles. Among them, technology is required to recognize static obstacles, such as poor road conditions, as well as dynamic obstacles, such as vehicles, bicycles, and people, that may be encountered while driving. In this study, we propose a deep neural network algorithm capable of simultaneously detecting these two types of obstacle. For this algorithm, we used 1,418 road images and produced annotation data that marks seven categories of dynamic obstacles and labels images to indicate road damage. As a result of training, dynamic obstacles were detected with an average accuracy of 46.22%, and road surface damage was detected with a mean intersection over union of 74.71%. In addition, the average elapsed time required to process a single image is 89ms, and this algorithm is suitable for personal mobility vehicles that are slower than ordinary vehicles. In the future, it is expected that driving safety with personal mobility vehicles will be improved by utilizing technology that detects road obstacles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.182-199
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• 2023

Since 2021, government departments have been promoting Automated Driving Technology Development and Innovation Project as national research and development(R&D) project. The automated vehicles and service technologies developed as part of these projects are planned to be subsequently provided to the public at the selected Living Lab City. Therefore, it is important to determine a spatial area and operation section that enables safe and stable automated driving, depending on the purpose and characteristics of the target service. In this study, the static Operational Design Domain(ODD) elements for Level 4 automated driving services were reclassified by reviewing previously published papers and related literature surveys and investigating field data. Spatial analysis techniques were used to consider the reclassified ODD elements for level 4 in the real area of level 3 automated driving services because it is important to reflect the spatial factors affecting safety related to real automated driving technologies and services. Consequently, a total of six driving mode changes(disengagement) were derived through spatial information analysis techniques, and the factors affecting the safety of automated driving were crosswalk, traffic light, intersection, bicycle road, pocket lane, caution sign, and median strip. This spatial factor analysis method is expected to be useful for determining special areas for the automated driving service.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.97-105
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• 2010

An All-red clearance interval(AR) has been operating with amber signal in order to avoid collision between vehicles which cannot come out of the intersections, vehicles coming in from the opposite direction, and pedestrians(bicycles) on the crosswalk during the signal conversion time at the intersections. Foreign nations have been analyzing AR's influences of traffic accidents. On the other hand, the similar research has not been conducted in the country. The objective of this paper, therefore, is to analyze the safety at the intersections with respect to the installation of AR through the hypothesis test. A before-and-after analysis has been performed for 10 intersections where applied AR. From the 95% of significance level, the results of Non-parametric Test show that the installation of AR improves a safety at the intersections. The results indicates that AR discharges vehicles passing through the intersections and control entering vehicles at the intersections.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.40-40
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• 2015

최근 기후변화로 인해 홍수의 발생빈도와 홍수량이 증가하고 있으며, 여름철 집중호우 및 태풍에 의해 하천의 둔치가 침수됨으로써 다양한 침수피해를 야기한다. 대하천 사업 이후 하천의 둔치를 활용한 체육시설, 자전거도로 및 생태공원과 같은 친수시설들이 조성되었으며 태풍으로 인한 하천의 홍수위 상승은 이러한 친수시설에 대한 직접적인 피해를 가져올 수 있다. 따라서 이와 같은 침수피해를 예측하기 위해서는 둔치를 포함한 복단면에서의 흐름해석을 통한 수리학적 영향을 분석해야하며, 둔치에서의 흐름양상은 주수로에 비해 수심이 얕고 흐름에 대한 저항이 크기 때문에 2차원 수리해석이 바람직한 것으로 제안되고 있다. 2차원 수리해석에 있어 하천의 홍수위 상승과 하강으로 인해 발생하는 둔치구간에서의 마름과 젖음 현상은 수치해의 발산을 야기하며, 이러한 문제를 해결하기 위해 다양한 마름/젖음 해석 기법에 대한 연구들이 진행되어 왔으며 일반적으로 마름/젖음에 대한 문제를 해결하는 방법은 마름/젖음에 상관없이 모든 부분에서 방정식을 푸는 박막기법과 해석영역으로부터 마름 부분을 제거하는 이동경계법으로 나눌 수 있다. 본 연구에서는 단기간에 수위가 급변하는 태풍사상에 대한 둔치에서의 홍수위험도를 평가하기 위해 마름/젖음 해석이 가능한 2차원 유한차분모형인 Nays2D 모형을 이용하여 마름/젖음에 대한 과거 선행연구들의 결과와 적용된 모형의 결과를 비교하여 모형의 적용성을 검증하였고, 검증된 모형을 강정-고령보에서부터 달성보 사이 구간에 적용하여 수리학적 영향을 분석하였다. 또한, 모형의 결과를 이용하여 홍수위험지수를 산정하였으며, 이를 통해 둔치구간에서의 홍수위험도 평가를 실시하였다.