• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.843-845
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• 2016

최근 AR(Argumented Reality), VR(Virtual Reality) 기술의 발달로 위치 기반 게임 및 증강 현실에 관한 관심이 높아지고 있으며, 다양한 서비스가 개발되고 있다. 이로 인해 AR, VR, MR(Merged Reality) 기술은 제 4차 산업혁명 기술 중 하나로 손꼽히고 있다. VR 기술의 대표격인 오큘러스 리프트나 HTC VIVE는 사용자의 조작을 위해 별도의 컨트롤러가 필요하며, 기기를 사용할 때 외부의 영상정보를 받아오는 형태의 서비스는 제공되지 않고 있다. 인텔의 MR 기기인 프로젝트 알로이의 경우 컨트롤러 없이 사용자의 손짓과 얼굴 표정 등으로 조작이 가능하며, 외부의 영상정보를 받아올 수 있는 장점이 있다. 본 논문에서는 MR을 이용하여 현재 위치를 기반 한 관광 안내 시스템을 제안한다. 제안하는 시스템은 MR을 통한 외부 영상정보와 GPS를 이용한 위치 측위, 무선 인터넷을 통한 관광 정보 검색을 통해 관광객의 현재 위치에 따른 관광지 정보를 위치에 맞게 배치하여 경제적인 관광이 가능케 한다.

• 품질경영학회지
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• 제46권4호
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• pp.899-910
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• 2018

Purpose: Generally, since the population density is lower in suburban areas, the distance to school is inevitably long. Therefore, schools in suburban areas often operate school buses to improve student welfare. However, since school buses are usually used only during going to and from school, the utilization rates are relatively low. Therefore, this study aims to establish integrated operation plan of public school bus covering all schools. Methods: It is necessary to decide which school buses will serve the specific demand node which want to go to certain school in order to design an integrated operation plan for school buses. Therefore, a mathematical model is developed for minimizing the total number of vehicles and the distance of transportation by reflecting the characteristics of school buses and students as constraints. To solve the proposed mathematical model, CPLEX, a commercial solver, is applied. Results: To validate and to confirm the proposed process, numerical example is designed with the comparison between before and after integrated operations of school buses in terms of total operation cost. The result shows that the integrated operation can lead the reduction of the number of school buses as well as the decreasing of the fuel cost. Conclusion: This study provides the quantitative method to perform the integrated operation of school buses in suburban areas. The optimal operation strategy is required because there are more complex decision-making elements considering the integrated operation. It is expected to apply this research result at real situation to expand this services based on an optimal operation.

• 한국전자통신학회논문지
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• 제14권2호
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• pp.361-368
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• 2019

본 논문은 전기차 기반의 1톤급 상용차용 통합공조 시스템에 관한 연구이다. 전기 상용차의 경우 화물의 승하차를 위해 문의 개폐가 빈번하게 이루어지기 때문에 열손실이 크게 발생한다. 따라서 냉난방 부하가 승용 전기차에 비해 더 크게 요구된다. 결과적으로 승객이 요구하는 열 쾌적성을 만족하기 위해서 냉난방 시스템이 소비하는 에너지가 승용 전기차 보다 크다. 이러한 단점을 극복하기 위해 효율적인 통합공조 시스템을 적용한 연구를 수행했다. 최종적으로 1톤급의 경상용 전기트럭의 상품성 개선과 전기트럭 분야의 산업 생태계 기반 확충을 위한 고효율 공조 시스템 개발을 위해 냉방을 위한 전동식 압축기와 난방을 위한 히트펌프 시스템의 구상 설계와 해석적 검증을 수행한다.

• 대한건축학회논문집:계획계
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• 제35권11호
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• pp.101-108
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• 2019

In this study, Le Corbusier's ideas were investigated from the view point of modern dualism. Le Corbusier, pioneer of modern architecture, insisted a rationalistic architecture for the industrial period, considering a house as 'machine for living'. In the other way, he tried to arouse emotions through architecture, mentioning a house as 'machine for affecting'. In his writings and paintings, he divided the world in the two opposed things (ex: human and nature, reason and sensation, chaos and order, orthogonal and libre curve, man and woman, sun and moon, lightness and darkness, bull and woman, and etc), and tried to combined the these two divided things. In architecture, he amalgamated his white buildings with the green vegetation, which is styled in the harmony of contrast(nature and articial). In urbanism, Le Corbusier did not divide nature only into three material elements for living(sunlight, air, green space), but also pursued poetic and aesthetic nature through buildings under the rays of sun and among the vegetation. Le Corbusier's dualistic ideas are based on Descartes's modern dualism, which divided the world into the material and the spiritual and into the objective and the subjective. Due to this original division, modern dualism contains the limits of extreme subjectification on human signification and of separation from the world and nature. Le Corbusier pursued the combination of the two divided things to overcome the contradiction of dualism, but his ideas and works contain the limits of the modern dualism.

• 정보보호학회논문지
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• 제22권3호
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• pp.601-613
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• 2012

안전한 웹 서비스를 제공하기 위하여 보안을 고려한 웹 애플리케이션의 설계와 구현이 요구되고 있다. 이에 따라 웹 애플리케이션의 취약성을 수치화할 수 있는 여러 가지 프레임워크들이 제시되고 있지만, 이러한 프레임워크에 의하여 도출된 수치는 누적 방식에 의하여 계산되기 때문에 취약점의 심각성을 제대로 분류할 수 없다는 문제점이 존재한다. 본 연구에서는 웹 애플리케이션에서 발생할 수 있는 취약점을 권한 획득 가능성에 따라 등급을 나누고 수치화함으로써 취약점에 대하여 우선순위를 둘 수 있다. 또한 개별 웹 애플리케이션뿐 아니라 한 조직에서 제공하는 여러 웹 애플리케이션에 대한 취약성을 수치화함으로써 어느 웹 애플리케이션이 가장 취약하며 우선적으로 처리해야 하는지 판단할 수 있다. 실제 크롤링 기반 웹 스캐너를 통하여 발견된 취약점들에 대하여 우리가 제안한 프레임워크를 적용하여 등급을 나누고 수치화함으로써 취약점의 권한 획득 가능성에 따른 분류의 중요성을 보이고 있다.

• Design & Manufacturing
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• 제14권4호
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• pp.17-24
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• 2020

Products for heating indoors in low temperature and dry winter are largely divided into products using fossil fuels and products using electricity. The fossil fuels can warm the entire space by convection, but there is a high risk of fire and the frequent ventilation due to the increase in carbon monoxide and carbon dioxide. Heaters using electricity are mainly used because they are convenient to use and are cheap. However, these products can not efficiently warm the air because they use radiation energy. In other words, only the front part exposed to the heater is warm, and the rear part has no heating effect at all. Also, because it emits a large amount of light, fatigue of the eyes is very high. Another problem is that when using electric heaters, the room tends to be dry by high heat. Indoor humidity maintenance is a very important factor in the prevention and treatment of respiratory diseases. Especially, it is essential for health care for infants, bronchial organs and people with weak respiratory because humidity is low in winter. In this study, we conducted a study to develop a product that can improve heating efficiency while maintaining proper indoor humidity by combining heat energy and moisture particles. The concept of humidification and heating at the same time, moisture particles generated in the humidifier pass through the heater, include thermal energy, and the moisture particles with thermal energy are diffused into the space by forced convection, thereby warming the entire space. In addition, the heating time is shortened as the feeling temperature is increased with the high relative humidity, and this has the effect that the heating cost in winter is reduced.

• Tribology and Lubricants
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• 제37권1호
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• pp.7-13
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• 2021

Ball bearing is a device that supports and transmits a load acting on a rotating shaft, and it is a type of rolling bearings that uses the rolling friction of the balls by inserting balls between the inner ring and the outer ring. Grease, which is prepared by mixing a thickener with a base oil, is a lubricant commonly used in bearings and has the advantage of a simple structure and easy handling. Bearings are increasingly being used in high value-added products such as semiconductors, aviation, and robots in the era of the 4th industrial revolution. Accordingly, there is an increasing demand for bearing grease. The selection of grease is an important factor in the bearing design. Therefore, a study must be conducted on the grease life evaluation to select an appropriate grease according to operating conditions such as a high temperature, high rotational speed, and high load. In this study, we evaluate the life of ball-bearing grease according to various operating conditions, namely, temperature, speed, and load changes. For this, we develop and theoretically verify a grease life test machine for ball bearings. We conduct a life test of grease according to various operating conditions of bearings and predict the grease life with a 10% and 50% failure probability using the Weibull analysis. In addition, we analyze the oxide characteristics of the grease over time using the Fourier transform infrared spectroscopy and the deterioration characteristics of the grease using the carbonyl index.

• 아태비즈니스연구
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• 제13권3호
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• pp.293-309
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• 2022

Purpose - The purpose of this study is to explore the possibility of predicting the degree of smartphone overdependence based on mobile phone usage patterns. Design/methodology/approach - In this study, a survey conducted by Korea Internet and Security Agency(KISA) called "problematic smartphone use survey" was analyzed. The survey consists of 180 questions, and data were collected from 29,712 participants. Based on the data on the smartphone usage pattern obtained through the questionnaire, the smartphone addiction level was predicted using machine learning techniques. k-NN, gradient boosting, XGBoost, CatBoost, AdaBoost and random forest algorithms were employed. Findings - First, while various factors together influence the smartphone overdependence level, the results show that all machine learning techniques perform well to predict the smartphone overdependence level. Especially, we focus on the features which can be obtained from the smartphone log data (without psychological factors). It means that our results can be a basis for diagnostic programs to detect problematic smartphone use. Second, the results show that information on users' age, marriage and smartphone usage patterns can be used as predictors to determine whether users are addicted to smartphones. Other demographic characteristics such as sex or region did not appear to significantly affect smartphone overdependence levels. Research implications or Originality - While there are some studies that predict smartphone overdependence level using machine learning techniques, but the studies only present algorithm performance based on survey data. In this study, based on the information gain measure, questions that have more influence on the smartphone overdependence level are presented, and the performance of algorithms according to the questions is compared. Through the results of this study, it is shown that smartphone overdependence level can be predicted with less information if questions about smartphone use are given appropriately.

• 한국기계가공학회지
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• 제21권9호
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• pp.98-104
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• 2022

Because a robot actuator is directly affected by the external force of the robot and accounts for the largest portion of the robot system weight, developing an optimized actuator suitable for each characteristic of the robot system is essential. Although there have been many developments and studies related to robot actuators in various industrial fields, lightweight and compact actuator designs that can control force are still lacking. In this study, a novel actuator module was developed, and its performance was verified experimentally. The structure and control of various robot systems can be optimized by utilizing the proposed actuator. It can be used for various tasks by sensing external force and through feedback control.

• 로봇학회논문지
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• 제17권2호
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• pp.142-151
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• 2022

With the advent of the 4th industrial revolution, autonomous driving technology is being commercialized in various industries. However, research on autonomous driving so far has focused on platforms with wheel-type platform. Research on a tracked platform is at a relatively inadequate step. Since the tracked platform has a different driving and steering method from the wheel-type platform, the existing research cannot be applied as it is. Therefore, a path-tracking algorithm suitable for a tracked platform is required. In this paper, we studied a path-tracking algorithm for a tracked platform based on a GPS sensor. The existing Pure Pursuit algorithm was applied in consideration of the characteristics of the tracked platform. And to compensate for "Cutting Corner", which is a disadvantage of the existing Pure Pursuit algorithm, an algorithm that changes the LAD according to the curvature of the path was developed. In the existing pure pursuit algorithm that used a tracked platform to drive a path including a right-angle turn, the RMS path error in the straight section was 0.1034 m and the RMS error in the turning section was measured to be 0.2787 m. On the other hand, in the variable LAD algorithm, the RMS path error in the straight section was 0.0987 m, and the RMS path error in the turning section was measured to be 0.1396 m. In the turning section, the RMS path error was reduced by 48.8971%. The validity of the algorithm was verified by measuring the path error by tracking the path using a tracked robot platform.