• 한국대기환경학회지
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• 제19권6호
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• pp.647-661
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• 2003

For continuous monitoring of atmospheric visibility in the city of Kwanaju, Korea, a transmissometer system consisting of a transmitter and a receiver was installed at a distance of 1.91 km across the downtown Kwanaju. At the transmitter site an integrating nephelometer and an aethalometer were also installed to measure the scattering and absorption coefficients of the atmosphere, respectively. At the receiver site. an URG PM$_{2.5}$ cyclone sampler and an URG-VAPS (Versatile Air Pollutant Sampler) with three filter packs and two denuders were used to collect both PM$_{2.5}$ and PM$_{10}$ samples at a 2-hour or 12-hour sampling interval for aerosol chemical analysis. Sulfate, organic mass by carbon (OMC), nitrate, elemental carbon (EC) components of fine aerosol were the major contributors to visibility impairment. Diurnal variation of visibility during best-case days showed rapid improvement in the morning hours, while it was delayed until afternoon during the worst-case days. Aerosol mass concentration of each aerosol component for the worst-case was calculated to be 11.2 times larger than the best-case for (NH$_4$)$_2$SO$_4$(NHSO), 19.0 times for NH$_4$NO$_3$ (NHNO), 2.2 times for OMC, respectively. Also result shows that elemental carbon and fine soil (FS) were 3.7 and 2.2 times more than those of best-case. respectively- Sum of total contributions of wet NHSO and NHNO to light extinction was calculated to be 301 Mm$^{-1}$ for the worst-case. However, sum of contributions by dry NHSO and NHNO was calculated to be 123 Mm$^{-1}$ for the best case. Mass extinction efficiencies of fine and coarse particles were calculated to be 5.8$\pm$0.3 $m^2$/g and 1.8$\pm$0.1 $m^2$/g, respectively.ely.

• 한국정보통신학회논문지
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• 제15권1호
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• pp.233-240
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• 2011

산악지역이나 어떤 한정된 지역에서 급작하게 나타나는 기상변화를 모니터링하기 위해 유비쿼터스 센서 네트워크 기술을 이용한 필드서버를 개발하였다. 국지적 기상변화에 의한 인명 및 재난 피해를 최소화하기 위해 국지역내에 배치된 필드서버간의 데이터 전달이 매우 중요한 기술이다. 일정한 국지적 지역에 배치 된 필드서버들로부터 일정한 시간 간격으로 수집되는 온도, 습도, 조도, 기압, 이슬점, 수위의 기상데이터를 전송하기 위한 플러딩 라우팅 프로토콜 전송방식을 구현하였으며, 이를 제작 된 외부센서모듈과 Telosb 계열의 센서노드에 nesC 언어를 사용한 초소형 무선센서네트워크 플랫폼인 TinyOS로 프로그램 하여서 서버 컴퓨터에서 모니터링 할 수 있도록 하였다.

• 대한교통학회지
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• 제29권3호
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• pp.41-48
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• 2011

차량의 각종 안전장치 및 운전자 모니터링 장치에서 운전자의 상태를 파악하려 할 때는 운전자, 자동차, 도로 환경의 측정 변수들이 통합적으로 수집되고 해석되어야 한다. 본 논문에서는 운전 상황을 통합적이고 종합적으로 분석하기 위하여 일정한 시간 주기로 운전자, 차량, 도로 주변 환경과 같은 다양한 영역으로부터 데이터를 동기화하여 수집하는 실시간 차량 모니터링 시스템을 제안한다. 제안한 시스템은 소프트 동기화 메커니즘으로 다중 정보를 동기화하여 수집한다. 이는 하나의 마스터 시간과 차량 상태와 운전자 상태 등의 다양한 영역의 데이터들의 키 값들을 동일한 시간 주기로 하나의 파일에 저장하고, 각각 다양한 영역의 데이터들은 저장할 때 마스터 시간과 함께 저장함으로써 후에 특정 시간에 운전 상황을 쉽게 찾아 볼 수 있게 한다. 본 논문에서는 구현된 시스템으로 9명의 피험자의 인지 부하 실험에서 데이터를 수집하는 예를 보인다.

• 자원환경지질
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• 제28권4호
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• pp.405-414
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• 1995

LANDSAT TM 자료를 이용한 지형변화를 관측하는데 알맞은 알고리즘에 대한 고찰과 이 알고리즘을 1986년 4월 15일과 1992년 9월 22일 경기만에서 얻어진 LANDSAT TM 자료에 적용하여 타당성을 시험하였다. 이 알고리즘은 변화벡터분석법과 tasseled cap 변환을 이용한 방법이다. 변화벡터분석법은 영상자료간의 변화를 관측하는데는 우수하지만 그 변화벡터의 수가 증가함에 따라 효율이 감소하는 단점이 있다. 이와 같은 단점을 보완하기 위해 tasseled cap 변환을 이용함으로서 원래 6개 밴드의 LANDSAT TM 자료를 두 개의 밴드 즉 Brightness와 Greenness로 줄일 수 있게 된다. 시험적용 결과 이 알고리즘은 해안선 일대에서의 대규모 지형변화뿐만 아니라 육안관측으로는 어려운 미세한 변화까지도 관측 가능한 것으로 나타났다. 그러나 본 연구결과의 변화벡터 영상에서는 인공적인 변화에 더 민감한 것으로 나타났는데 이는 본 연구에 사용된 두 LANDSAT TM 자료가 얻어진 시간 간격이 지질학적 작용에 의한 변화가 나타나기에는 비교적 짧기 때문인 것으로 사료된다.

• Coupled systems mechanics
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• 제5권2호
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• pp.191-201
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• 2016

Coupled structures are widely seen in civil and mechanical engineering. In coupled structures, monitoring the translational motion of its key components is of great importance. For instance, some coupled arms are equipped with a hydraulic piston to provide the stiffness along the piston axial direction. The piston moves back and forth and a distance sensing system is necessary to make sure that the piston is within its stroke limit. The measured motion data also give us insight into how the coupled structure works and provides information for the design optimization. This paper develops two distance sensing systems for coupled structures. The first system measures distance with ultrasonic sensor. It consists of an ultrasonic sensing module, an Arduino interface board and a control computer. The system is then further upgraded to a three-sensor version, which can measure three different sets of distance data at the same time. The three modules are synchronized by the Arduino interface board as well as the self-developed software. Each ultrasonic sensor transmits high frequency ultrasonic waves from its transmitting unit and evaluates the echo received back by the receiving unit. From the measured time interval between sending the signal and receiving the echo, the distance to an object is determined. The second distance sensing system consists of a wire draw encoder, a data collection board and the control computer. Wire draw encoder is an electromechanical device to monitor linear motion by converting a central shaft rotation into electronic pulses of the encoder. Encoder can measure displacement, velocity and acceleration simultaneously and send the measured data to the control computer via the data acquisition board. From experimental results, it is concluded that both the ultrasonic and the wire draw encoder systems can obtain the linear motion of structures in real-time.

• 한국대기환경학회지
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• 제25권4호
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• pp.325-338
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• 2009

National parks provide recreation, health, and science to human being. The provision of beautiful landscape view of the national park improves an economic and social phase of a nation. However, visibility impairment frequently occurred in the national park area of Gyeongju. The purpose of this study is to investigate the physical and the chemical characteristics of visibility reduction observed at the national park area of Gyeongju. Optical, chemical, meteorological characteristics and scenic monitoring were performed at the visibility monitoring station of Gyeongju University located at the Seoak section of Gyeongju national park from April 28 to May 9, 2008. Light extinction, light scattering, and light absorption coefficients were continuously measured using a transmissometer, a nephelometer, and an aethalometer, respectively. In order to investigate the impact of aerosol chemistry on visibility impairment, size-resolved aerosols were collected at intervals of 2-hour (from 8 A.M. to 6 P.M.) and 14-hour (from 6 P.M. to 8 A.M.) interval each sampling day. The average light extinction coefficient and the average visual range were measured to be $270{\pm}135\;Mm^{-1}$ and $14.5{\pm}6.3\;km$ during the intensive monitoring period, respectively. It was revealed that sulfate particle was the largest contributor to the light extinction under hazy condition. Organic mass accounted for about 26% of the average light extinction. The mass extinction efficiencies for $PM_{1.0}$, $PM_{2.5}$, and $PM_{10}$ were estimated to be 9.0, 4.7, and $2.7\;m^2\;g^{-1}$ under the consideration of water growth function of hygroscopic aerosols, respectively.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.241-246
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• 2006

The paper presents the preparations work and experiences gained from realtime GPS car monitoring during the European Rally Championships organized on 10-12 June 2005 in Poland. The developed system is based on GPS and GSM/GPRS technology. Distribution and teletransmission of data are possible using different GSM operators in Poland, which makes the system fully independent. The system's server collects data from rally cars, processing and send data through VPN connections to the SQL server located in main control room. Data can be collected in real time via Internet or GPRS. Some information on GSM/GPRS range during rally championships are also presented in the paper. The study covered many trials and tests of different software and various configurations of the GPRS modems before finally the system started to work. Information coming from 10 Rally Cars were collected to the SQL Server continuously in one second interval. In real time mode these all data were displayed simultaneously in the rally main control room and in the rally press conference room. Paper describes also adopted emergency procedures and remote reconfiguration of GPS/GPRS boxes inside rally cars made during championships. Some problems and method of practical solutions are presented to avoid active jamming dangerous for a driver and his pilot, having system of communication intercoms jammed by teletransmission of GPRS 900/1800 MHz. In cooperation with rally teams special GPS/GPRS safety boxes were designed and made. Monitoring of all 7 rally stages with GPS receivers and method of calibrations of the maps were presented. GSM signal coverage was also checked in all stages. All data transmitted from rally cars were recorded in the computer. Some of our GPS cars had accidents and dispite them information were continuously sent to server. There is possibility to show in post mission mode the position of chosen cars in our rally application. Some information of best rally cars are presented also in the paper.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.223-225
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• 2010

최근 국지적 지형이나 지역에서 급작하게 나타나는 기상현상에 대한 정보의 수집으로 인명피해 및 재난피해를 최소화시키기 위한 재해예방 모니터링 시스템에 대한 연구가 활발하게 진행 중이다. 기존의 재해예방 시스템은 일정한 국지적 장소에 배치되어 재해요소를 무선센서네트워크를 적용하여 베이스 스테이션으로 일정한 시간 간격을 두고 연속적으로 전송함으로써 효율적인 전력에 대한 문제점들이 제기되어 왔다. 본 논문에서는 재해예방 모니터링 시스템의 효율적인 데이터 전송을 위하여 일정 시간 간격으로 측정되는 온도, 습도, 조도 등의 기상데이터들을 센서노드의 플래시 메모리에 순차적이고 신속하게 저장한 후 한 번에 버스트(Burst) 형태로 전송하는 방법을 제시하고, 이를 Telosb 계열의 센서노드에 nesC 언어를 사용한 초소형 무선센서네트워크 플랫폼인 TinyOS로 프로그램 하였다.

• Diabetes and Metabolism Journal
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• 제42권6호
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• pp.480-487
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• 2018

Background: This study aimed to evaluate the relationship between the frequency of self-monitoring of blood glucose (SMBG) and glycosylated hemoglobin (HbA1c) levels among Korean adolescents with type 1 diabetes mellitus (T1DM). Factors affecting the SMBG frequency were analyzed in order to improve their glycemic control. Methods: Sixty-one adolescents aged 13 to 18 years with T1DM were included from one tertiary center. Clinical and biochemical variables were recorded. Factors associated with SMBG frequency were assessed using structured self-reported questionnaires. Results: Average total daily SMBG frequency was $3.8{\pm}2.1$ and frequency during the school day was $1.3{\pm}1.2$. The mean HbA1c level was $8.6%{\pm}1.4%$. As the daily SMBG frequency increased, HbA1c levels declined (P=0.001). The adjusted odds of achieving the target HbA1c in participants who performed daily SMBG ${\geq}5$ significantly increased 9.87 folds (95% confidence interval [CI], 1.58 to 61.70) compared with those performed SMBG four times a day. In the subjects whose SMBG frequency <1/day during the school day, an 80% reduction in the adjusted odds ratio 0.2 (95% CI, 0.05 to 0.86) showed compared to the group with performing two SMBG measurements in the school setting. The number of SMBG testing performed at school was significantly high for individuals assisted by their friends (P=0.031) and for those who did SMBG in the classrooms (P=0.039). Conclusion: Higher SMBG frequency was significantly associated with lower HbA1c in Korean adolescents with T1DM. It would be necessary to establish the school environments that can facilitate adequate glycemic control, including frequent SMBG.

• 한국농공학회논문집
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• 제61권6호
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• pp.73-79
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• 2019

Continuous and tremendous data (canopy temperature and meteorological variables) are necessary to determine Crop Water Stress Index (CWSI). This study investigated the optimal monitoring time and interval of canopy temperature and meteorological variables (air temperature, relative humidity, solar radiation and wind speed) to determine CWSIs. The Nash-Sutcliffe model efficiency coefficient (NSE) was used to quantitatively describe the accuracy of sampling method depending upon various time intervals (t=5, 10, 15, 20, 30 and 60 minutes) and CWSIs per every minute were used as a reference. The NSE coefficient of wind speed was 0.516 at the sampling time of 60 minutes, while the ones of other meteorological variables and canopy temperature were greater than 0.8. The pattern of daily CWSIs increased from 8:00 am, reached the maximum value at 12:00 pm, then decreased after 2:00 pm. The statistical analysis showed that the data collection at 11:40 am produced the closest CWSI value to the daily average of CWSI, which indicates that just one time of measurement could be representative throughout the day. Overall, the findings of this study contributes to the economical and convenient method of quantifying CWSIs and irrigation management.