• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.122-126
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• 2005

Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a two-year period from 1999 to 2001 the monitoring wells were sampled every three months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land-use and temporal change.

• Journal of the Korea Society of Computer and Information
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• v.20 no.8
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• pp.53-59
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• 2015

Noise from the surrounding environment, building structures and machine equipment have significant effects on daily life. Many solutions to this problem have been suggested by analyzing causes of noise generated from particular locations in general buildings or machine equipment and detecting defects of buildings or equipment. Therefore, this paper suggests a visualization technique of sounds by using the microphone array to measure sound sources from machines and perform the visual machine condition monitoring (VMCM). By analyzing sound signals and presenting effective sound visualization methods, it can be applied to identify machine's conditions and correct errors through real-time monitoring and visualization of noise generated from the plant machine equipment.

• Journal of Soil and Groundwater Environment
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• v.23 no.1
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• pp.30-40
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• 2018

To evaluate potential impacts of shallow groundwater by the leachate from buried carcass, we investigated hydrochemical characteristics of both leachate and shallow groundwater from monitoring wells and surrounding shallow groundwater wells in an area potentially affected by pig carcass burial. The hydrochemical survey was conducted before and after the relocation of a burial pit. The leachate samples and the groundwater affected by leachate showed the hydrochemistry of $Ca-HCO_3$ type with high $NH_4{^+}$ concentrations, while unaffected groundwater was mostly the $Ca(Na)-Cl+NO_3$ type due to pervasive impacts from agrochemicals. The results of factor analysis on hydrochemical data showed the followings: 1) contamination of groundwater from agro-livestock farming and livestock burial are coexisting in the study area, 2) among ionic species, $HCO_3{^-}$, $NH_4{^+}$, $NO_3{^-}$ and Mn are very useful to differentiate the groundwater contamination from leachate, and 3) groundwater contamination by leachate has been recognized around the monitoring wells even after the relocation of a burial pit, likely due to residual contaminants in surrounding soils. Therefore, it is suggested that continued monitoring of groundwater contamination should be conducted after the relocation of carcass burial pits.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.558-569
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• 2007

It is important to obtain real-time data from long-term monitoring of landfills and develop leachate leakage detection system for the integrated management of landfills. A novel real time monitoring system and early leakage detection system was suggested in this study. The suggested monitoring system is composed of two parts; (1) a set of moisture sensors which monitor the areas surrounding the landfill, and (2) a set of moisture and temperature sensors which monitor the landfill inside. For the assessment for landfills stabilization, real-time monitoring system was evaluated in dry and wet cell of pilot-site. In addition, the grid-net electrical conductivity measurement system was also suggested as early leakage detection system. In this study, the field applicability of suggested systems was evaluated through pilot-scale field tests. The results of pilot-scale field model tests indicate that the grid-net electrical conductivity measurement method can be applicable to the detection of landfill leachate at the initial stage of intrusion, and thus has a potential for monitoring leachate leakage at waste landfills.

• Journal of Radiation Protection and Research
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• v.14 no.2
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• pp.51-62
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• 1989

The high efficiency moderated-type neutron spectrometer and doseequivalent counter were developed for the measurement of low level environmental neutrons. By using these detectors, the neutron energy spectra and dose equivalent rates due to skyshine effect were measured in the environment surrounding the accelerator facilities and also the altitude variation of cosmic ray neutrons in the aircraft flying over Japan.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.432-438
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• 2010

In this paper, we propose a system which can perceive status of semiconductor equipment and evaluate its performance. The proposed system acquires the information such acceleration, pressure, temperature and gas sensors in the surrounding semiconductor equipment. After acquiring information, it is sent to server through multi hop transmission. The transmitted data generates 3 steps alarm using context-aware algorithm of unit or multiple event. From the experiment's result of the proposed system, we confirm that the reliability and efficiency of information is more improved about 80% than a system that doesn't use context-aware algorithm. Moreover, this system can be effective status monitoring of semiconductor equipment because lots of client nodes acquire surrounding information.

• Journal of the Korean Society of Visualization
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• v.20 no.1
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• pp.45-51
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• 2022

Airborne particulate matter(PM) has been a global environmental problem. PM whose diameter is smaller than 10 ㎛ can permeate respiratory organs and has harmful effects on human health. Therefore, PM monitoring systems are necessary for management of PM and prevention of PM-induced negative effects. Conventional PM monitoring techniques are expensive and cumbersome to handle. In the present study, two types of PM monitoring devices were designed for measuring indoor PM concentration, portably. We experimentally investigated the performance of three commercial PM concentration measurement sensors in a closed test chamber. As a result, PM2008 sensor showed the best PM concentration measurement accuracy. Linear regression method was applied to convert PM concentration value acquired from PM2008 sensor into ground truth value. A mobile application(app.) was also created for users to check the PM concentration, easily. The mobile app. also provides safety alarm when the PM₁₀ concentration exceeds 81 ㎛/m³. The developed hand-held system enables the facile monitoring of surrounding air quality.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.05a
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• pp.28-44
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• 1993

Remediation actions in uncontrolled landfill site should be conducted after the investigation of contamination status and potential health risk or damage. Based on the above, proper control measures should be established and operated. Also continuous monitoring should be followed. In this study, the status of ground water contamination around Nanji Landfill Site was investigated. Monitoring wells were installed around the landfill and ground water was sampled once a month and analyzed. Water quality of each monitoring well was different depending on the horizontal and vertical distance from the landfill, and the seasonal leachate characteristics were not significantly changed because percolating water stayed long time in the deep waste layer. It was predicted that major multivalent cations were mainly precipitated as metal carbonate form, and chemical mass balances (CMBs) could be applied for the apportionment of leachate contamination to ground water quality of surrounding areas of Nanji Landfill. Parameters required to estimate pollutant flux to the receptor near landfill were listed and discussion to get these parameters was made. Finally, based on the above data, control measures of ground water contamination were suggested and discussed.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.1
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• pp.39-55
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• 2011

Process monitoring has been emphasized for the monitoring of complex system such as chemical processing industries to achieve the efficiency enhancement, quality management, safety improvement. Recently, ICA (Independent Component Analysis) based MSPC (Multivariate Statistical Process Control) was widely used in process monitoring approaches. Moreover, DICA (Dynamic ICA) has been introduced to consider the system dynamics. However, the existing approaches show the limitation that their performances are strongly dependent on the statistical distributions of control variables. To improve the limitation, we propose a novel approach for process monitoring by integrating DICA and LOF (Local Outlier Factor). In this paper, we aim to improve the fault detection rate with the proposed method. LOF detects local outliers by using density of surrounding space so that its performance is regardless of data distribution. Therefore, the proposed method not only can consider the system dynamics but can also assure robust performance regardless of the statistical distributions of control variables. Comparison experiments were conducted on the widely used benchmark dataset, Tennessee Eastman process (TE process), and showed the improved performance than existing approaches.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.955-960
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• 2011

This study was aimed at investigating the applicability of energy harvesting technologies, which are regarded as new and renewable energy sources for real-time/wireless monitoring of intelligent railroad vehicles. The surrounding energy generated in a normal operating environment was monitored using a high-speed railroad vehicle in operation. This monitoring was performed in an attempt to evaluate the effectives of energy harvesting and the applicability of energy-harvesting-monitoring technologies under the conditions in which thermal energy and vibration energy are generated.