• 한국터널지하공간학회 논문집
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• 제20권1호
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• pp.73-81
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• 2018

본 논문은 지하구조물 계측센서의 내구연한 기준에 대한 규정 분석 연구로 국내 건설공사 발주기관의 건설 계측센서에 대한 내구연한 기준을 조사 분석하고, 법인세 시행규칙에서 건축물 등의 기준 내용연수 및 조달청의 건설계측 및 건설기계 관련 내용연수 기준을 분석하였다. 지하 구조물에 설치되기 전 조달청에서 물품 자체로 구매하는 경사계와 변형률계 등의 내구연한 기준은 8년에서 10년을 제시하고 있으나, 건설공사 시 원 지반 및 콘크리트 구조물 내에 설치된 계측센서는 지하수 영향 및 다짐 등 여러 가지 불리한 요인으로 물품 자체의 내용연수보다는 상당 기간 단축될 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.67-76
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• 2020

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that tend to persist in environmental media for a long period of time. This work presents a 2-year monitoring study of occurrence of three PAHs (benzo(a)pyrene, naphthalene, and fluoranthene) in groundwater. The groundwater samples were collected from 106 sites of nation's groundwater quality monitoring network and analyzed by simultaneous analysis method to quantify the concentrations of the PAHs. Benzo(a)pyrene was not detected in all samples. Naphthalene and fluoranthene concentrations ranged from not detected to 12.8 ng/L and not detected to 10.5 ng/L with their detection frequency being 57.8 and 4.2%, respectively. The concentrations of PAHs in ground- and drinking waters are not currently regulated in Korea, but the concentration levels of naphthalene and fluoranthene found in this work were lower than the regulatory limits of other countries (naphthalene 0.001~0.07 mg/L, fluoranthene 0.001~1.4 mg/L). The monitoring result of this study revealed that PAHs exist as trace amounts in domestic groundwater, however continuos monitoring is necessary to protect groundwater from PAHs contamination with growing industrialization and urbanization.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.639-641
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• 2022

사회적으로 고령화 문제가 심화되면서, 독거노인 모니터링 시스템에 관한 연구가 활발히 진행되고 있다. 일반적으로 모니터링 시스템은 영상, 센서, 계측값 등의 정보를 바탕으로 서버에서 연산을 수행하여, 사용자에게 모니터링 서비스를 제공한다. 서버를 이용하는 시스템의 구조상 데이터 유출의 위험이 존재하며, 데이터 보안을 고려한 설계가 필수적이다. 본 논문에서는 영상보안 구조 기반의 지능형 독거노인 모니터링 시스템을 제안한다. 제안하는 시스템은 Edge AI 모듈을 사용하여 카메라 모듈과 서버 간의 통신을 차단하는 구조를 통해 높은 보안성을 보장한다. Edge AI 모듈은 Verilog HDL로 설계되었으며, Field Programmable Gate Array (FPGA)를 통해 기능을 구현하였다. 본 시스템을 검증하기 위해 5,144개의 프레임 데이터에 대해 실험하였으며, 사람의 움직임이 일정 시간 감지되지 않았을 때 위험 감지 신호가 올바르게 발생하는 것을 확인하였다.

• 대한치과교정학회지
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• 제52권2호
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• pp.123-130
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• 2022

Objective: To evaluate if a remote digital monitoring system added at the end of orthodontic treatment could positively influence the retention phase by reducing the occurrence of misfit of removable appliances, number of emergency appointments (EA), and orthodontic relapse. Methods: Twenty-seven patients who completed active orthodontic treatment were divided into the study and control groups. In addition to the standard chairside follow-up appointments at month 1 (T1), month 3 (T2), month 6 (T3), the study group patients were monitored using Dental Monitoring^® with monthly intra-oral scans. Occurrence of misfit of removable retainers, number of EAs, and intercanine width change were recorded for both groups. Differences in EAs and retainer fit were assessed using the chi-square test. Intra-group and inter-group differences in the intercanine width were assessed with Friedman test and Mann-Whitney U test, respectively (α = 0.05). Results: The study group showed a significantly lower occurrence of misfit of removable retainers (p = 0.027) compared to the control group. No significant inter- and intra-group difference was found in the EAs and intercanine width change at each time-point. Conclusions: Integrating remote monitoring systems, such as Dental Monitoring^®, to the retention phase of the orthodontic treatment may lower the occurrence of misfit of removable retainers. However, a small sample size and a short observation period limit the strength of this evidence. These preliminary results tentatively suggest that remote monitoring technologies may be beneficial, especially during the COVID-19 pandemic, when the regularity of in-office visits might be disrupted.

• 대한원격탐사학회지
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• 제38권6_1호
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• pp.1343-1356
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• 2022

광학위성영상을 이용해 농작물을 모니터링 할 때 가장 문제가 되는 것은 구름이나 그림자이다. 구름과 그림자의 영향을 줄이기 위해 일정 주기동안 최대 정규식생지수를 선택하는 합성기법이 사용되었다. 그러나, 본 방법은 구름의 영향을 줄이기는 하나, 일정 주기 동안 최대 정규식생지수(Normalized Difference Vegetation Index, NDVI)값만을 사용하기 때문에 NDVI가 감소하는 현상을 신속히 보여주기 어렵다. 이에 따라, 구름의 영향을 최소화하면서 식생의 분광정보를 최대한 유지하기 위한 방안으로 합성 시 여러 환경인자를 정의하고, 이에 대한 점수를 부여하여 합성 시 가장 적합한 화소를 선택하는 방법인 점수 기반 합성기법이 제시되었다. 본 연구에서는 Sentinel-2A/B Level2A 반사율 영상과, 부가정보로 제공되는 구름, 그림자, Aerosol Optical Thickness(AOT), 촬영날짜, 센서천정각 등을 이용한 점수 기반 식생지수 합성기법을 개발하였다. 2021년동안 당진 논지역과 태백 고랭지 배추밭을 대상으로 15일 주기와 한달 주기로 점수기반 합성기법을 적용한 결과, 구름의 영향을 받은 우기만을 제외하고 15일 주기 합성 시 한달 주기에 비해 보다 빠르고 자세한 NDVI값의 변화를 볼 수 있었다. 특정 영상에서는 합성 NDVI영상에서 부분적으로 날짜별 차이가 나타나 공간적으로 이질적인 부분이 보이기도 하는데, 이는 사용한 구름, 그림자 정보의 부정확성으로 인한 것으로 사려된다. 향후 입력정보의 정확도를 향상시키고, Maximum NDVI Composite (MNC) 기반 합성기법과 정량적 비교를 수행할 예정이다.

• Environmental Engineering Research
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• 제14권1호
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• pp.13-18
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• 2009

In this study, specific pollutant releases during the Asian monsoon season were estimated and the information was applied to the non-point pollutant sources management from two forested watersheds of the Soyang Lake. The two watersheds are part of the 2,703 km2 Soyang Lake watershed in the northern region of the Han River. The outlets of the two watersheds were respectively analyzed for continuous water quality concentration and for discharge during various single rainfall events. Statistical power function methods are utilized to compare stream discharge and pollutant flux release during the study period. Based on the monitoring data during the study period, the specific load flux method using simulated discharge was conducted and validated in the two watersheds. The model predictions corresponded well with the measured and calculated pollutant releases. The modeling approach taken in this study was found to be applicable for the two forested watersheds.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.449-454
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• 2006

We present a pressure sensor based on the mechanically induced long-period fiber gratings (LPFG) for detecting the multi-location strain variation. The theoretical analysis is performed using a graphic method for a weakly guiding step-index fiber. The calculated results are in good agreement with the experimental results. In this study, from the fact that the optical parameters of a single-mode fiber slightly differ from manufacturing company to manufacturing company, the multipoint pressure-detection sensor systems composed two identical LPFGs are realized. When the pressure is applied two LPFG sensors at once, the resonance peaks are separated as much as about 40 nm. These types of sensor systems are well suited as a multipoint monitoring of strain or temperature in the ship or the smart structure.

• 한국대기환경학회지
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• 제11권2호
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• pp.199-209
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• 1995

The variations of TSP concentrations observed at Air Quality Monitoring Stations(AQMSs) in Seoul were analysed from 1986 to 1993. And those of Yellow Sand period were investigated to find out the characteristics between normal and Yellow Sand period. The TSP concentrations have begun lower than 150.mu.g/m$^{3}$ annual mean concentration at Gwanghwamun, Hannam-dong, and south river region since 1989, and air quality in Seoul was improved in 1991, but polluted again in Hannam-dong, and Seongsu-dong in 1992. Yellow sand phenomena of 1990 and 1993 were selected for case study. During the whole period in 1990, the TSP concentrations were exceeded over 300.mu.g/m$^{3}$, which is the upper limit of 24 hour concentration, at the center of city such as Mapo, Gileum-dong, sinseol-dong. But in 1993, the TSP concentrations got lower than 24 hour concentration, and air quality was highly improved.

• 대한원격탐사학회지
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• 제26권6호
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• pp.721-730
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• 2010

In satellite remote sensing, irregular temporal sampling is a common feature of geophysical and biological process on the earth's surface. Lee (2008) proposed a feed-back system using a harmonic model of single period to adaptively reconstruct observation image series contaminated by noises resulted from mechanical problems or environmental conditions. However, the simple sinusoidal model of single period may not be appropriate for temporal physical processes of land surface. A complex model of multiple periods would be more proper to represent inter-annual and inner-annual variations of surface parameters. This study extended to use a multi-periodic harmonic model, which is expressed as the sum of a series of sine waves, for the adaptive system. For the system assessment, simulation data were generated from a model of negative errors, based on the fact that the observation is mainly suppressed by bad weather. The experimental results of this simulation study show the potentiality of the proposed system for real-time monitoring on the image series observed by imperfect sensing technology from the environment which are frequently influenced by bad weather.

• 한국대기환경학회지
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• 제20권5호
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• pp.603-613
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• 2004

Extensive forest fires occurred across the border in Russia. particularly east of Lake Baikal between the Amur and Lena rivers in May 2003. These forest fires released large amounts of particulates and gases into the atmosphere. resulting in adverse effects on regional air quality and the global radiation budget. Smoke pollution from the Russian fires near Lake Baikal was sometimes transported to Korea through Mongolia and eastern China. In this study ground based radiation (visible and UV-B) data measured during May 2003 at Seoul and Kwangju were analyzed to estimate smoke aerosol impacts on solar radiation. Surface criteria air pollutants ($PM_{10}$, CO, $O_3$) data were also obtained from National Institute of Environmental Research (NIER) during smoke aerosol event period (19 May~24 May 2003). Large Aerosol Optical Depth (AOD) 1.0~3.0 was observed during this period due to the influence of the long range transport of smoke aerosol plume from the Russian fires, resulting in short-wavelength direct aerosol radiative forcing of -90~ -200W/$m^2$. These smoke aerosol plume caused decrease in surface UV-B radiation up to 80% and increase in PM_(10) concentration up to 200${\mu}g/m^3$ exceeding the 24 hour ambient air quality standard.