• 대한원격탐사학회지
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• 제40권1호
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• pp.1-8
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• 2024

Busan is the 6th largest port city in the world, where nitrogen dioxide (NO₂) emissions from transportation and port industries are significant. This study aims to assess the NO₂ products of the Geostationary Environment Monitoring Spectrometer (GEMS) over Busan using ground-based instruments (i.e., surface in-situ network and Pandora). The GEMS vertical column densities of NO₂ showed reasonable consistency in the spatiotemporal variations, comparable to the previous studies. The GEMS data showed a consistent seasonal trend of NO₂ with the Korea Ministry of Environment network and Pandora in 2022, which is higher in winter and lower in summer. These agreements prove the capability of the GEMS data to monitor the air quality in Busan. The correlation coefficient and the mean bias error between the GEMS and Pandora NO₂ over Busan in 2022 were 0.53 and 0.023 DU, respectively. The GEMS NO₂ data were also positively correlated with the ground-based in-situ network with a correlation coefficient of 0.42. However, due to the significant spatiotemporal variabilities of the NO₂, the GEMS footprint size can hardly resolve small-scale variabilities such as the emissions from the road and point sources. In addition, relative biases of the GEMS NO₂ retrievals to the Pandora data showed seasonal variabilities, which is attributable to the air mass factor estimation of the GEMS. Further studies with more measurement locations for longer periods of data can better contribute to assessing the GEMS NO₂ data. Reliable GEMS data can further help us understand the Asian air quality with the diurnal variabilities.

• 응용통계연구
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• 제26권1호
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• pp.93-109
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• 2013

지리통계자료는 관측지점이 지도 상에 점으로 표현되고 그 지점에서만 자료가 관측되는 측정값이다. 이러한 지리통계자료는 매우 다양한 관측망에서부터 얻어진다. 지리통계자료를 분석하고 예측함에 있어서 하나의 자료만 이용하는 것보다는 유사한 패턴을 갖는 다른 관측망에서 얻어지는 여러 자료들을 함께 사용한다면 예측력을 향상시킬 수 있을 것이다. 본 논문에서는 서로 다른 관측망에서 얻은 두 가지의 공간자료를 이용하여 분석 및 예측하고 이를 위해 공간적 연관성을 파악할 수 있는 적절한 계층모형을 구축하였다. 그리고 선형회귀모형에 근간을 둔 크리깅 결과와 계층모형 하에서의 결과를 여러 검증방법을 통해 비교하였다. 이 논문에서는 도시대기측정망에서 측정된 이산화황과 지상기상관측망에서 측정된 풍속자료를 이용하여 계층모형을 구축하고 이산화황만을 이용한 선형모형과 비교하였다. 또한 각 모형에 의한 이산화황 예측지도를 구성하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.21-25
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• 2002

Activated sludge processes are widely used in biological wastewater treatment processes. The main motivation of this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent rate, weather conditions, and so on. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP model based on Matlab/Simulink is designed in this paper. The performance of the model is tested by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data that include steady-state results during 14 days. In this paper, fuzzy logic control approach is applied to control the DO (dissolved oxygen) concentration. The fuzzy logic controller that includes two inputs and one output can adjust air flowrate. Also, this paper introduces the remote monitoring and control system that is applied for the CSTR (Continuously Stirred Tank Reactor) wastewater treatment system. The CSTR plant has a local control and the remote monitoring system which is contained communication parts which consist of LAN (Local Area Network) network and CDMA (Code Division Multiple Access) wireless module. Remote control and monitoring systems are constructed in the laboratory.

• 한국대기환경학회지
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• 제30권5호
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• pp.504-509
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• 2014

Twenty-five stations of the urban monitoring network in Seoul were assessed with a focus on surveillance function of the exceedances of 8-hour ozone and 24-hour $PM_{10}$ standards. The two standards were selected because their attainment rates were particularly low. Two hierarchical cluster analyses were performed to group stations with similar atmospheric environments-one using daily highest 8-hour [$O_3+NO_2$], 8-hour $O_3$ concentrations plus corresponding 8-hour $NO_2$ concentrations considering the interconversion of $O_3$ and $NO_2$, and the other using 24-hour $PM_{10}$ concentrations. An index to measure higher concentration and exceedances of the standards was introduced. Within a cluster, sufficiently high score was assigned to the trends station or the station with higher index. Scores for $O_3+NO_2$ and $PM_{10}$ of a given station were added and ranked in the descending order to determine the relative importance.

• Structural Monitoring and Maintenance
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• 제1권2호
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• pp.183-195
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• 2014

Scour is one of the leading causes of overwater bridge failures worldwide. While monitoring systems have already been implemented or are still being developed, they suffer from limitations such as high costs, inaccuracies, and low reliability, among others. Also, most sensors only measure scour depth at one location and near the pier. Thus, the objective is to design a simple, low cost, scour hole topography monitoring system that could better characterize the entire depth, shape, and size of bridge scour holes. The design is based on burying a robust, waterproofed, piezoelectric sensor strip in the streambed. When scour erodes sediments to expose the sensor, flowing water excites it to cause the generation of time-varying voltage signals. An algorithm then takes the time-domain data and maps it to the frequency-domain for identifying the sensor's resonant frequency, which is used for calculating the exposed sensor length or scour depth. Here, three different sets of tests were conducted to validate this new technique. First, a single sensor was tested in ambient air, and its exposed length was varied. Upon verifying the sensing concept, a waterproofed prototype was buried in soil and tested in a tank filled with water. Sensor performance was characterized as soil was manually eroded away, which simulated various scour depths. The results confirmed that sensor resonant frequencies decreased with increasing scour depths. Finally, a network of 11 sensors was configured to form a distributed monitoring system in the lab. Their exposed lengths were adjusted to simulate scour hole formation and evolution. Results showed promise that the proposed sensing system could be scaled up and used for bridge scour topography monitoring.

• 설비공학논문집
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• 제21권8호
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• pp.462-467
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• 2009

Researches and developments on BEMS are performed world-widely through sustainable management in various conditions. However, there are many obstacles to adapt the system in existing buildings because it needs highly expensive equipments, which are designed for newly built buildings, to install. Therefore, there are numerous limits exist when applying the BEMS in established buildings. The purpose of this study estimates the optimization of RF output power in WSN(Wireless Sensor Networks), which is the essential technology to develop PEMS. The results of this study is as follows ; 1) Applying WSN technique in buildings was possible. 2) As RF output power increases, the number of relay node reduced, therefore, the WSN showed more stability. 3) When estimating optimal RF output power in school, it should be considered between the number of relay node and RF output power. 4) Considering battery consumption and possibility of reception, the best suited RF output power is -20dbm in apartment house.

• 대한원격탐사학회지
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• 제36권4호
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• pp.637-643
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• 2020

In this study, the information from environmental impact statements was converted into spatial data because environmental data from development sites are collected during the environmental impact assessment (EIA) process. Spatiotemporal big data were built from environmental spatial data for each environmental medium for 2,235 development sites during 2007-2018, available from public data portals. Comparing air-quality monitoring stations, 33,863 measurement points were constructed, which is approximately 75 times more measurement points than that 452 in Air Korea's real-time measurement network. Here, spatiotemporal big data from 2,677,260 EIAs were constructed. In the future, such data might be used not only for EIAs but also for various spatial plans.

• 전기학회논문지
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• 제65권12호
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• pp.2075-2083
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• 2016

The real time IAQ (Indoor Air Quality) management is very important for large buildings and underground facilities such as subways because poor IAQ is immediately harmful to human health. Such IAQ management requires monitoring, prediction and control in an integrated and real time manner. In this paper, we present three PM10 hourly prediction models for such realtime IAQ management as both Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) models. Both MLR and ANN models show good performances between 0.76 and 0.88 with respect to R (correlation coefficient) between the measured and predicted values, but the MLR models outperform the corresponding ANN models with respect to RMSE (root mean square error).

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1470-1475
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• 2009

Until now for the safety of structures and equipment monitoring technology to measure the amount of the physical, if that is the one, one-point or single-source target is one the most. Therefore, becoming more numerous and complex to measure the amount of physical measurement technology that is comprehensive and complex, multi-source concepts to the monitoring of a multi-sensing technology is required. Have the same characteristics of multi-source multi-use space such as a multi-structure of facilities/equipment is. The people's safety in a multi-use facility will be directly related to life and even a little carelessness can lead to large-scale disaster occurs because of several factors, risks and to manage detect in advance the development of an intelligent monitoring technology is essential. Therefore, this study shows that multiple structures/facilities to improve the quality of human life in research to maintain a safe and comfortable living space for multi-source intelligence to the development of monitoring technology to achieve that goal, and the ubiquitous sensor network system on the basis of the wireless transmission module, and multiple research facilities/equipment for the ultra-small sensors for health monitoring study was performed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.485-488
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• 2000

This paper proposes to design the residential power line communication device using Softwire Protocol, which targets the device with 8bit micro-controller and small-size memory based on low-rate power line communication network or wireless communication network. As a case study, the SCP message specification of air-conditioner that has capability of control and monitoring its status is designed using Softwire Protocol. And, it is described how the device operates sequentially.