• 제어로봇시스템학회논문지
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• 제15권3호
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• pp.293-299
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• 2009

This paper discusses an autonomous navigation system for urban environments. For the localization of the robot, EKF (Extended Kalman Filter) algorithm is used with odometry, angle sensor, and DGPS (Differential Global Positioning System) measurement. Especially in an urban environment, DGPS is often blocked by buildings and trees and the resulting inaccurate positioning prevents the robot from safe and reliable navigation. In addition to the global information from DGPS, the local information of the curb on the roadway is used to track a route when the global DGPS information is inaccurate. For this purpose, curb detection algorithm is developed and implemented in the developed navigation algorithm. Four different types of navigation strategies are developed and they are switched to adapt to different localization conditions according to the availability of DGPS and the existence of the curbs on the roadway. The experimental results show that the designed switching strategy improves the navigation performance adapting to the environment conditions.

• 한국환경보건학회지
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• 제15권2호
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• pp.1-9
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• 1989

A pilot study was conducted in order to measure indoor and outdoor formaldehyde levels during August 3 - 22, 1988 in several underground spaces in Seoul. Formaldehyde concentrations were monitored during 1 week in selected sampling areas (subway station, underground shopping center, underpass, tunnel, underground parking lot) using passive formaldehyde monitors. In order to investigate a relationship between respiratory prevalence and levels of formaldehyde, each subject was asked to answer respiratory questions. The mean formaldehyde concentrations were 60.1 ppb in subway station, 122.2 ppb in underground shopping stores, 72.1 ppb in underpasses, 39.7 ppb in tunnel, and 75.9 ppb in underground parking lots, respectively. The mean indoor formaldehyde concentrations in underground environments varied from 28.6 ppb to 118.7 ppb. Generally, the mean formaldehyde concentrations in ticketing office in subway stations appeared higher than those level measured in platform. The mean formaldehyde concentrations of underground shopping center in Gangnam Terminal were higher than any other areas and it exceeded 100 ppb of the American Ambient Air Quality Standards of formaldehyde. Prevalence rates of respiratory symptoms of dwellers seemed to be related to higher indoor formaldehyde levels.

• 한국전자파학회논문지
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• 제12권6호
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• pp.912-918
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• 2001

본 논문에서는 광대역 WLL신호환경에서 동작하는 스마트 안테나 시스템의 역방향 채널에서의 시스템 성능분석을 제시하였다. 이 논문에 보여지는 모든 결과는 현재 상용화 된 단말기로부터 수신한 실제 데이터로부터 얻어졌다. 웨이트 벡터로부터 계산되어진 빔패턴과 BER(Bit Error Rate)은 실내와 실외 환경 실험에서 관찰되었다. 실험의 결과로, 제안되어진 스마트 안테나 시스템은 실외와 실내 신호 환경 모두에서 향상된 성능을 제공한다는 결론을 얻었다.

• 한국생활과학회지
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• 제19권1호
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• pp.203-214
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• 2010

This study will examine the current condition of outdoor play in child care centers and the overall perception of teachers on outdoor play in regards to its related programs and children's reaction to them. Through examining such issues, this study will provide the basic data that can be applied in planning appropriate outdoor play activities, programs and environments. For the study, we surveyed teachers and directors of child care centers using a structured questionnaire. The objects of the survey were 22 child care centers in Daejeon and Seoul, who agreed to conduct the survey. The survey was conducted from August 1 to September 30 2006; 220 copies were distributed, and 188 copies were collected. The results of the study can be summarized as follows: 1) The number of outdoor plays per week were on average 1~2 in most cases, although teachers believed the play should be done everyday. Outdoor play time was mostly 21~30 minutes, while teachers thought 31~40 minutes as appropriate. Children's reaction scored the highest when they played outdoors for 30 minutes every day with their teachers involved in the play. As a result, we have concluded that the appropriate outdoor play should be conducted everyday for 30~40 minutes. 2) Outdoor play was mostly conducted as part of the overall educational plan rather than a separate plan. Since outdoor play affects children's development as much as indoor play, there is a need for development of a specific and separate plan for various outdoor play programs. 3) The outdoor play program that was most often conducted was equipment play and sand play. This indicated the monolithic nature of the outdoor program. Given the fact that children enjoy outdoor plays a lot (M=4.71), various programs including adventure play, sensitive play, and carpenter play should be developed. 4) In outdoor play, the teacher's role included supervising and interacting with children. According to the survey, teachers had a good understanding of the importance on safety and supervising issues in outdoor plays. However they seemed to overlook the importance of having better programs and improving teacher's participation to the play. Despite the importance of outdoor play to children's development, the result shows that teachers have tendencies to limit and obstruct outdoor plays by emphasizing supervising and safety issues instead. 5) Children's safety should not be the only consideration for outdoor plays; teachers ought to better understand that children's development can be maximized by the play. Furthermore, there should be emphasis placed on the program development and teacher's participation; teacher's participation should actively encourage the interactions between a child and a teacher, as well as among children.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3965-3983
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• 2017

We propose a novel eye tracking method that can estimate 3D world coordinates using an infrared (IR) stereo camera for indoor and outdoor environments. This method first detects dark evidences such as eyes, eyebrows and mouths by fast multi-level thresholding. Among these evidences, eye pair evidences are detected by evidential reasoning and geometrical rules. For robust accuracy, two classifiers based on multiple layer perceptron (MLP) using gradient local binary patterns (GLBPs) verify whether the detected evidences are real eye pairs or not. Finally, the 3D world coordinates of detected eyes are calculated by region-based stereo matching. Compared with other eye detection methods, the proposed method can detect the eyes of people wearing sunglasses due to the use of the IR spectrum. Especially, when people are in dark environments such as driving at nighttime, driving in an indoor carpark, or passing through a tunnel, human eyes can be robustly detected because we use active IR illuminators. In the experimental results, it is shown that the proposed method can detect eye pairs with high performance in real-time under variable illumination conditions. Therefore, the proposed method can contribute to human-computer interactions (HCIs) and intelligent transportation systems (ITSs) applications such as gaze tracking, windshield head-up display and drowsiness detection.

• 한국농촌건축학회논문집
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• 제20권4호
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• pp.39-51
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• 2018

In order to improve the housing environment and quality of life for the rural elderly, this study aims to identify and present the status of community centers, most widely used by the elderly in rural areas. Through the literature review, type and space elements of community centers were derived and selected three target areas were investigated. As a result of literature analysis, the space type of rural community centers were classified as indoor space and outdoor space. The indoor space types were classified as entry space, public space, sanitary space and the outdoor space were classified as entry space and leisure space. Some community centers were surveyed in Seocheon-gun, Wanju-gun, and Cheongju-city. Results indicate the indoor and outdoor space design and elements were undergoing a lot of inconvenience partly because standard design was considered and the space was not planned for the physical, psychological and social health of the rural elderly. Therefore, this study will be used as a basis for building healthier and more friendly residential environments that can enhance the health and quality of life for the elderly in rural areas.

• 제어로봇시스템학회논문지
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• 제17권10호
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• pp.995-1005
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• 2011

An efficient outdoor local localization method is suggested using multi-sensor fusion with MU-EKF (Multi-Update Extended Kalman Filter) for car-like mobile robots. In outdoor environments, where mobile robots are used for explorations or military services, accurate localization with multiple sensors is indispensable. In this paper, multi-sensor fusion outdoor local localization algorithm is proposed, which fuses sensor data from LRF (Laser Range Finder), Encoder, and GPS. First, encoder data is used for the prediction stage of MU-EKF. Then the LRF data obtained by scanning the environment is used to extract objects, and estimates the robot position and orientation by mapping with map objects, as the first update stage of MU-EKF. This estimation is finally fused with GPS as the second update stage of MU-EKF. This MU-EKF algorithm can also fuse more than three sensor data efficiently even with different sensor data sampling periods, and ensures high accuracy in localization. The validity of the proposed algorithm is revealed via experiments.

• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.954-962
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• 2002

In a park or street, we can see many people jogging or walking with their dogs tracking their masters. In this study, an entertainment robot that imitates a dog's behavior is created. The robot's task is tracking a moving target that is recognized as the master. In order to design the robot, the ecological approach. in which the robot's goals and surroundings heavily influence its design, is used. A three-wheel type locomotion system is designed as the robot's physical structure which can follow a human jogging in outdoor space like a park. A sensor system which can detect the position of a master for the robot in the outdoor space, is developed. This sensor system consists of a signal transmitter which is at the hand of a master and some sensors which are mounted on the robot. The transmitter emits RF(radio frequency) and ultrasonic signals and the sensors detect the direction and distance from the robot to the transmitter by using the received signals. For the control architecture of the robot, a purely reactive behavior-based method is used in order to increase speed of response. The developed robot is evaluated through experiments conducted in indoor and outdoor environments.

• 한국대기환경학회지
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• 제14권3호
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• pp.163-176
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• 1998

In this study, airborne particle samples were obtained to determine the concentrations of particulate air pollutants in indoor and outdoor air of public facilities in Taegu area. Total of 12 public facilities, regulated by the Public Sanitary Law, were selected as sampling sites, which include three underground arcades, one railway and two bus terminals, three general hospitals, and three department stores. In each place, sampling was carried out seasonally during the period of October 1994 to July 1995, and four samples per each site per season were collected both indoors and outdoors simultaneously. After determination of suspended particulate matter (SPM) mass concentrations, the particle samples were divided into two parts for subsequent chemical analysis: one for the analysis of trace elements and the other for water soluble ions. Seasonal levels of SPM appeared to be the highest in spring and the lowest in summer both indoors and outdoors, while locational variations of highest in statioyterminals, and lowest in department stores . SPM concentrations indoors and outdoors did not show any significant differences each other in most places . However, there were significant correlations between indoor and outdoor levels of SPM and other chemical species . These results indicates that indoor SPM levels are likely to be significantly affected by outdoor sources in many places. The most significant source of SPM was estimated to be the resuspension of soil/road dust both indoors and outdoors . The concentrations of toxic heavy metals (Pb, Cd, Cr, Cu) in underground arcades appeared to be very much lower than the established air quality guidelines for underground environments. In addition, it is likely that micro-environmental parameters such as temperature, humidity, and air velocity, play a less significant role than outdoor air quality as a factor affecting the levels of particulate pollutants in indoor environments of public facilities in Taegu area.

• 한국컴퓨터정보학회논문지
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• 제25권7호
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• pp.85-92
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• 2020

사물인터넷(Internet of Things: IoT) 기술 발전에 따라서, IoT기술의 적용범위는 실내 환경의 생활 편의성 개선에서 벗어나 실외 환경에서의 발생가능한 위험을 사전에 감지·예방하는 산업안전 분야로 확대되고 있다. 이러한 IoT서비스 확대는 많은 장점을 제공함에도 데이터 유출과 변조 등의 보안 문제도 함께 발생시키므로 이에 따른 보안 대응전략 연구도 활발히 진행되고 있다. 본 논문에서는 실외환경에서의 IoT기반 도로건설 위험방지시스템을 연구대상으로 IoT 보안관리 가이드라인을 제안한다. 연구대상에 적용한 저전력-광역(LPWA, BLE) 통신프로토콜의 보안취약점을 조사한 결과, 정보보안의 3대 요소인 기밀성, 무결성, 가용성 측면에서 보안취약점을 확인하여 이를 최소화할 수 있도록 취약점 별 대응방안을 제안하였다. 본 연구는 기 구현된 실외환경에서의 IoT기반 도로건설 위험방지시스템 운영에서 발생할 수 있는 취약점 조사·분석과 취약점별 실질적인 보안지침을 제안하는데 연구의 의의가 있다.