• Journal of IKEEE
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• v.15 no.1
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• pp.76-85
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• 2011

In this paper, we analysed RSS characteristics by external factors and presented an efficient algorithm for real-time location tracking and its hardware system. The proposed algorithm enhanced the ranging accuracy using Kalman Filter based on the RSS DB. The location tracking system that consists of the tag, AP(Access Point), a data collector(Data Receiver) with IEEE 802.15.4(ZigBee) network environment, and location tracking application that reveal locations of each tag is implemented for the test environment. The location tracking system presented in this paper is implemented with MSP430 microprocessor manufactured by TI(Texas Instrument), CC2420 RF chipset and the location tracking application. With the results of the experiment, the proposed algorithm and the system can achieve the efficiency and the accuracy of location tracking with the average error of 19.12cm, and its standard deviation of 5.31cm in outdoor circumstance. Also, the experimental result shows that exact tracking of position in indoor circumstance cannot achieve because of vulnerable RSS with external circumstance.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.847-858
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• 2015

Bacillus amyloliquefaciens GR4-5 was isolated from the rhizosphere soil of Korean ginseng and displayed broad-spectrum suppression of ginseng root rot pathogens. The survivability of B. amyloliquefaciens GR4-5 in soil was investigated under three different conditions; indoor, outdoor - of which soil was put in 14 mL tube after treatment - and field environments. Soil samples were collected over a four-week period from three experimental designs, and assessed for 16S rRNA gene copy number by quantitative polymerase chain reaction (qPCR). In outdoor condition, the 16S rRNA gene copy number of Bacillus spp. was 8.35 log copies g $soil^{-1}$ immediately after the GR4-5 treatment. Two weeks later, the 16S rRNA gene copy number of Bacillus spp. (6.70 log copies g $soil^{-1}$) was similar to that of the control (6.38 log copies g $soil^{-1}$). In indoor condition, the 16S rRNA gene copy number of Bacillus spp. maintained in a certain level for a longer period than those in outdoor and field. The 16S rRNA gene copy number of Bacillus spp. in field experiment was reduced faster than that of outdoor condition. Our results show that B. amyloliquefaciens GR4-5 can survive in bulk soil for 1 week, indicating its potential use as a biocontrol agent following 7 day application intervals. This study presents that outdoor microcosm system design could be a useful method to assess easily the survivability of beneficial microorganisms.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.47-54
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• 2018

This study examined the behavior of red fox (Vulpes vulpes) during the estrus period, breeding period, and mating including the estrus period along as well as the effect of environmental factors in an outdoor breeding facility. The average mating duration was 19.95 min (n = 13, range = 1.17-35.25 min). The breeding season was mainly early February (56.6%) for foxes aged more than one year and mid-March (60.0%) for foxes aged less than one year. The mating duration was longest when both male and female were more than one year old ($24.4{\pm}11.08min$), although copulation took place regardless of partner's age. Females that mated twice within two days after estrus started or with two males had 100% pregnancy rate. In addition, the pregnancy rate was highest (87%) when both mating partners were more than one year old. Foxes preferred daytime to nighttime for mating, and thus mating usually took place on sunny days or between 10:00 and 12:00 on partly cloudy days. A male mated with different females for a maximum of five times, and the higher the mating frequency of a male, the longer the mating duration. Interest in mating decreased after three copulations in the case of males and after two copulations in the case of females. Males required at least 4 hours and 46 minutes between the first and second copulation. For this study, we collected reference data that might be applied to breeding programs for the red fox to secure the restoration of individuals of this important species.

• Journal of the Korean housing association
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• v.19 no.6
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• pp.105-114
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• 2008

The purpose of this study is to classify playground types according to the physical characteristics of playgrounds in child care facilities, to analyze the needs of care-givers and to evaluate the adequacy of playgrounds according to playground types. The specific areas discussed in this study were the evaluation of the adequacy in the physical characteristics of playgrounds for children's outdoor play activities by the care-givers, who assist in the outdoor play activities of children and manage safety in the playground, and a report on playground requirements of them. Data was collected from field survey carried out to investigate the physical characteristics of playgrounds of 21 child care facilities. This survey incorporated a structured-questionnaire for the purpose of evaluating the adequacy of the physical characteristics of playgrounds (location and size of the playground, play equipments, the composition of play areas, ground covers, and location of sidewalk in the playground) by the 181 care-givers from the facilities and investigating the needs of them. The major results showed the following. 1) In field survey, it was observed that while the location and the size of the playgrounds varied widely, ground cover, play equipments, and the composition of play area turned out to be identical, regardless of the location and the size of the playgrounds. 2) The playgrounds were classified into five types according to the number of children and the size of the playground. The five types include A-type as a large-scale facility/smallsize playground, B-type as a small-scale facility/large-size playground, C-type as a small-scale facility/small-size playground, D-type as a middle-scale facility/large-size playground, and E-type as a large-scale facility/large-size playground. 3) The adequacy of the physical characteristics of playground in the D-type was evaluated to be higher than that of the other types. The adequacy of the C-type playground was evaluated to be lower than that of the other types in terms of size and the composition of play areas within the playground. 4) The care-givers of the D-type and the E-type playground expressed a desire to install various play equipments, while the care-givers of the C-type playground did not wish to install play equipment. 5) Various outdoor play areas were needed in the D-type playground.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.499-503
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• 2005

The objective of this thesis is to measure the limit of the real space where wireless Local Area Network(LAN) is used, and to apply this result as reference to set up a real Wireless LAN environment. The organized circumference was composed of Wireless LAN based on IEEE 802.11b of the American standard, and the examination is carried out on the campus. On the real condition of office environment and open space, the ratio of available distance to a signal at each distance was measured and this result was studied as data to embody wireless LAN on the campus. The measurement under an indoor environment was executed under circumstance having two wall and open space, however, was executed respectively under three circumstances : Where no obstacle, where one wall exists, and where two or more walls exist.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.243-252
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• 2005

Purpose: Indoor air quality (IAQ) in the radiation treatment center which is generally located underground is important to the health of hospital workers and patients treated over a long period of time. this study was conducted to measure and analyze the factors related to IAQ and subjective symptoms of sick building syndrome, and to establish the causes influencing IAQ and find a solution to the problems. Methods and Materials : Self administrated questionnaire was conducted to check the workers' symptoms and understanding of the work environment. Based on a preliminary investigation, the factors related to IAQ such as temperature, humidity, fine particulate. carbon dioxide, carbon monoxide, formaldehyde, total volatile organic compounds (TVOC), and radon gas were selected and measured for a certain period of time in specific sites where hospital workers stay long in a day. And we also evaluated the surrounding environment and the efficiency of the ventilating system simultaneously, and measured the same factors at the first floor (outdoor) to compare with outdoor all quality, All collected data were assessed by the recommended standard for IAQ of the domestic and international environmental organizations. Results: Hospital workers were discontented with foul odors, humidity and particulate. They complained symptoms related to musculo-skeletal system, neurologic system, and mucosal-irritatation. Most of the factors were not greater than the recommended standard, but the level of TVOC was third or fourth times as much as the measuring level of some offices in the United States. The frequency and the amount of the ventilating system were adequate, however, the problem arising in the position of outdoor-air inlets and indoor-air outlets involved a risk of the indraft of contaminated air. A careful attention was a requirement in handling and keeping chemical substances including a developing solution which has a risk of TVOC emissions, and repositioning the ventilating system was needed to solve the contaminated-air circulation immediately Conclusion We verified that some IAQ-related factors and inadequate ventilating system could cause subjective symptoms in hospital workers. The evaluation of IAQ was surely needed to improve the underground working environments for hospital workers and patients. On the basis of these data, from now on, we should actively engage in designs of the department of radiation oncology or improvement in environments of the existing facilities.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.223-235
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• 2004

Objectives: This study was to evaluate the actual condition of falls among community-dwelling elderly people and its related factors to prepare for the establishment of comprehensive prevention programs of senior population. Methods: The study subjects included 460 home residents over 65 years in a district of Chungnam Province and interviews were given to all of them, asking about experiences of falls and their related factors. The analysis of study results came to the following conclusions. Results: The rate of falls among total subjects was 35.5%. With the percentage by age and sex, over 70's and female were significantly higher than male(p=0.000) and under 69 (p=0.008). The groups with poor visual acuity and hearing ability had higher rate of falls than the normal groups based on their health status. In terms of place they experienced falls, out-door occurrence accounted for 53.4% of total falls, which was higher 46.6% of in-door. By season when falls are experienced, "winter" showed the greatest rate, and by time of the day, evening had the highest rate. By causes of falls, "Slippery ground"accounted for 30.5% and "Tumbled over" 23.5% of total falls, respectively, showing the major role of environmental causes for falls. For individual factors, "Irritability" and "Carelessness" occupied 11.3%, 10.8% of total falls, respectively. The Odds Ratios for falls in women was 2.19 times higher than in men, and those in 70's are 2.01 times higher than in 60's, and those with abnormal BMI was 3.68 times higher than in normal groups, and those with perceived symptoms was 1.94 times higher than those without. Conclusions: It is suggested that more consideration should be directed toward taking comprehensive and systematic prevention measures ranging from setting-up the injury-protective environments to allowing senior citizens to have competence in ADL activity as well as proper general health conditions, considering the higher rate of falls for elderly persons in a rural part of this country than that of western countries and the greater proportion of falls which can be ascribed to environmental factors.

• Information and Communications Magazine
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• v.23 no.4
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• pp.23-34
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• 2006

WiBro 서비스는 휴대형 단말기를 통해 실외에서도 정지 및 이동중에도 고속도로 인터넷에서 접속하여 필요한 정보나 멀티미디어 컨텐츠를 이용할 수 있게 하는 통신 서비스이다. WiBro 유무선통합커뮤니케이션 서비스는 WiBro 뿐만 아니라 유선 초고속 인터넷, 무선랜 등 통합 환경에서 메신저, 영상대화, MMS, e-메일 등 다양한 커뮤니케이션 서비스를 제공하는 서비스로 언제 어디서나 사용자가 상대방과 연결될 수 있는 유비쿼터스 커뮤니케이션을 제공한다. 다양한 단말, 장비기기들 및 사업자간의 상호 운용이 가능하도록 IMS(IP Multimedia Subsystem) 아키텍처를 기반으로 SIP 표준 프로토콜을 사용하여 구축되었으며 IP 커뮤니케이션을 중심으로 다양한 응용서비스 연동 및 제공이 가능하다.

• 기계와재료
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• v.23 no.3
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• pp.190-198
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• 2011

하이브리드 굴삭기는 에너지 재생 및 연비향상을 위하여 기존의 유압부품들 중 일부를 전기부품으로 대체하여 시스템을 구성하고 있다. 따라서, 하이브리드 굴삭기의 신뢰성을 평가하고 보장하기 위해서는 기계적인 부하와 전기적인 부하가 복합적으로 영향을 미쳐 발생되는 고장모드를 고려하여 신뢰성평가기법을 개발하여야 한다. 특히 하이브리드 굴삭기는 가혹한 실외 환경조건에서 운용되므로 새롭게 개발되는 부품들에 대하여 설계 결함을 조기에 발견하기 위한 복합 내환경 시험과 초가속 수명시험이 수행되어야만 한다. 본 연구에서는 FMEA, FMECA, FTA 및 HALT 등의 다양한 신뢰성 기법을 사용하여 하이브리드 굴삭기의 신뢰성평가기법을 개발하였고, 개발대상 하이브리드 굴삭기의 주요 동력전달 파트인 선회구동 시스템에 대한 신뢰성평가장비를 개발하고 구축하였다. 본 연구에서 개발된 하이브리드 굴삭기 신뢰성평가기법은 하이브리드 자동차의 부품들에 대한 신뢰성평가에도 유용하게 사용될 수 있을 것으로 기대된다.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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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.