• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.29-43
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• 2021

본 연구에서 제약식프로그래밍을 이용하여 제약식 있는 동적계획법 모형을 푸는 한 방법을 제시한다. 현재 제약식 있는 동적계획법을 다루는 방법은 각 단계별 제약식들의 상태를 일반적인 동적계획법의 상태공간에 추가하여 마치 제약식이 없는 동적계획법 방식을 적용하는데 반해, 이 연구에서 제시하는 방식은 제약식의 상태가 제약식프로그래밍의 변수 도메인으로 표현되고 저장된다. 계산에 있어서도 일반적인 동적계획법의 벨만방정식의 해법과 함께 제약식을 다루기 위한 제약식프로그래밍의 확산-추론 방법을 사용하는 하이브리드 방식을 따른다. 이 두가지 방식의 비교를 위해 특별히 장기 자동차 렌탈 문제를 제시하고 이 문제의 단순화된 모형을 중심으로 다른 방식으로 해결하는 과정을 보고 그 장단점을 논한다.

• Design & Manufacturing
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• 제12권3호
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• pp.25-30
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• 2018

Recently The automotive industry is trying to increase the energy efficiency by reducing the weight of the car body and engine components as a way to achieve high energy efficiency. In particular, the reduction of the weight of the vehicle through the weight reduction of the vehicle body has the advantage that the fuel consumption and the output can be improved. But at the same time, there is the disadvantage that the strength becomes weak due to the reduction of the material thickness. Therefore, in order to overcome these disadvantages, materials with high strength according to the unit thickness have been actively developed, and researches for applying them have also been increasing. In this study, we will investigate the application of cold rolled steel sheet, which is a lightweight material, to a horn bracket that secures a installed in an automobile engine room. The horn bracket secures the horn on the car engine and is bolted to the outer wall of the engine. The momentum is acted on the bracket due to the distance between the bolt fastening part and the car horn installed on the bracket end side. Therefore, the body part of the bracket is more likely to be destroyed by the influence of the continuous stress. In this paper, design optimization for weight reduction and strength enhancement was performed to solve this problem, and possibility of applying the rolled steel sheet material as lightweight material by tensile test and fabrication was confirmed.

• 한국ITS학회 논문지
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• 제22권4호
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• pp.211-225
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• 2023

미래 모빌리티 환경에서 인포테인먼트 시스템은 사용자와 차량을 연결하는 중추적 역할을 수행할 것으로 예상된다. 이 연구는 커넥티드카 인포테인먼트 애플리케이션인 안드로이드 오토의 사용자 리뷰에서 사용자 경험 요인을 도출하고, 만족도에 영향을 미치는 요인을 분석하여 인포테인먼트 시스템의 만족도 개선 방안을 제안하였다. 이를 위해 인포테인먼트 시스템 사용자 경험 요인을 구성하고, 토픽 모델링을 통해 실제 사용자 리뷰에서 도출한 토픽을 적용하였다. 감성분석과 로지스틱 회귀분석 결과, 만족도에 긍정적 영향을 미치는 요인으로 사용 용이성과 이해 용이성이, 불만족 요인으로 유연성과 안전성, 유희성이 도출되었으며, 이를 기반으로 설계 개선 전략을 제안하였다.

• Journal of Welding and Joining
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• 제21권7호
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• pp.34-41
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• 2003

Weld quality monitoring and seam tracking along the butt-joint lengthwise to the tube axis are studied. The material of tube is 60kg/$\textrm{mm}^2$ grade steel sheet, and the longitudinal butt-joint is shaped by 2 roll bending machine. The tube with a thickness of 1.5mm, diameter of 105.4mm and length of 2000mm is successfully obtained by the $CO_2$ laser welding system equipped with a seam tracker and plasma sensor. Experimental results show that the developed welding system can be used for the precision seam tracking and the real-time monitoring of weld quality, and the laser welded tube can be used for car body md component after tubular hydroforming.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.267-275
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• 2021

Smart application is developed in this paper by using an android-based platform to automatically determine the human emergency state (Lifesaver) by using different technology sensors of the mobile. In practice, this Lifesaver has many applications, and it can be easily combined with other applications as well to determine the emergency of humans. For example, if an old human falls due to some medical reasons, then this application is automatically determining the human state and then calls a person from this emergency contact list. Moreover, if the car accidentally crashes due to an accident, then the Lifesaver application is also helping to call a person who is on the emergency contact list to save human life. Therefore, the main objective of this project is to develop an application that can save human life. As a result, the proposed Lifesaver application is utilized to assist the person to get immediate attention in case of absence of help in four different situations. To develop the Lifesaver system, the GPS is also integrated to get the exact location of a human in case of emergency. Moreover, the emergency list of friends and authorities is also maintained to develop this application. To test and evaluate the Lifesaver system, the 50 different human data are collected with different age groups in the range of (40-70) and the performance of the Lifesaver application is also evaluated and compared with other state-of-the-art applications. On average, the Lifesaver system is achieved 95.5% detection accuracy and the value of 91.5 based on emergency index metric, which is outperformed compared to other applications in this domain.

• 한국정보통신학회논문지
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• 제10권1호
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• pp.212-219
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• 2006

퍼지 논리 제어기(FLC : Fuzzy Logic Controller)를 사용할 때, 가장 중요한 것은 소속 함수의 범위를 정하는 것과 규칙의 형태를 결정하는 것이다. 소속 함수의 범위나 규칙의 형태는 자금까지 전문가가 임의로 정하는 방법을 사용하였다. 그러나 기존의 방법을 사용하면, 전문가의 주관적인 규칙과 소속 함수가 생성될 수 있고, 소속함수의 경우 최적의 범위를 정확히 예측하기 어려운 단점이 있다. 본 논문에서는 이런 단점을 보완하기 위해, 유전자 알고리즘을 사용함으로써 최적의 소속 함수와 규칙의 형태를 구하려 하였다. 제시하는 방법의 타당성을 검증하기 위해 자동차 주행 제어 문제에 적용시켜 보았다.

• 한국정밀공학회지
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• 제33권7호
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• pp.529-534
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• 2016

During the past few years, several incidents of freight car wheel failure during operation have occurred due to fatigue crack and overheating from braking. Tensile residual stress on the wheel tread creates an environment conducive to the formation of thermal cracks that may threaten the safety of train operations. It is important to investigate the residual stress on wheels in order to prevent derailment. In the present paper, the residual stress on wheels is measured using the x-ray diffraction system and the residual stress is analyzed using FEM. The result shows that the residual stress on the wheel rim is lower than that on the wheel tread center and the stress on over-braked wheels changes from compression residual stress to tensile residual stress.

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1181-1188
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• 2014

In this paper, we propose a novel concept foran unmanned delivery service using a cooperative heterogeneous unmanned system consisting of a self-driving car and an unmanned aerial vehicle (UAV). The proposed concept is suitable to deliver parcels in high-density and high-rise urban or residential areas. In order to achieve the proposed concept, we will develop acooperative heterogeneous unmanned system. Customers can order goods using a smartphone application and the order information, including the position of the customer and the order time, and the package is transported automatically by the unmanned systems. The system assigns the tasks suitable for each unmanned vehicle by analyzing it based on map information. Performance is validated by experiments consisting of autonomous driving and flight tests in a real environment. For more evaluation, the landing position error analysis is performed using circular error probability (CEP).

• 대한교통학회지
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• 제33권3호
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• pp.223-236
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• 2015

이 연구는 교통사고감소를 위한 자동차보험의 지역요인 반영에 대해 다루고 있다. 연구의 목적은 지역별 자동차보험 적용방안에 대한 과학적인 검증절차를 수립하는데 있다. 이를 위해 이 연구는 지역별로 서로 다른 교통환경 요인에 대한 자동차보험 손해율과의 상관분석을 수행하였으며, 그 타당성을 검증하였다. 또한, 교통사고의 주된 원인인 인적요인에 해당하는 교통문화를 지역별로 구분하여 손해율간의 상관관계와 모형도를 제시하였다. 이러한 결과를 토대로 지역별로 교통사고를 유발하는 다양한 교통환경이 있음에도 불구하고 자동차보험요율은 획일적으로 적용되고 있는 문제점을 제기하였으며, 이를 해결하기 위한 방안으로 지역요인을 반영한 자동차보험정책의 도입을 주장하였다.

• 한국컴퓨터정보학회논문지
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• 제22권2호
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• pp.89-95
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• 2017

There are a variety of apps that are finding their way. And in car navigation, we launched a product that reflects Augmented Reality technology this year. However, existing apps have problems. It is implemented in 2D or 3D, has a large error range because it has been modified in most vehicles, is not updated in real time, and car augmented reality navigation is a vehicle, and a separate device is required, etc. In this study, we implemented a smartphone app for walking directions using augmented reality, and made it possible to intuitively use a route service from a user 's location to a destination. The Dijkstra algorithm is applied to calculate the shortest path to solve the problem of finding the route with the least cost. By using this application, it is possible to use the route search service even in a data-free environment, to solve the inconvenience of the language barrier, and to update in real time, so that the latest information can be always maintained. In the future, we want to develop an app that can be commercialized by using a character in the path to promote it.