• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.4
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• pp.185-192
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• 2011

To predict contaminant concentrations within a multi-zone work environment, an air quality model in the work environment was developed. To do this, airflow equations on the basis of orifice equation were solved by using the Conte and De Boor scheme, and then equations for the conservation of mass on contaminant were solved by using the fourth-order Runge-Kutta algorithm. To validate the accuracy of simulated results, this model was applied to the controlled environment chamber that had been tested in 1998 by Chung KC. The comparison of predicted concentrations by this study with measured concentrations by the Chung KC indicated that the average deviations were 2.66, 3.35, and 3.15% for zone 1, zone 2, and zone 3, respectively. Also, this model was applied to a working plant with four zones. Thus, the results of contaminant concentration versus time were predicted according to the schedule of the openings operation, and case studies were done for four cases of the openings operation to investigate the interaction of airflow and contaminant concentration. The results indicated that opening operation schedules had a significant effect on contaminant removal efficiency. Therefore, this model might be able to apply for the design of ventilation schedules to control contaminants optimally.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.105-115
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• 2020

With the decrease of the agricultural population in Korea, the workers who is vulnerable to labor are increasing in agricultural industry because of aging, feminization of population. They are exposed in poor working environment with higher temperature and concentrations of dust, gas. Higher concentration of harmful gas and dust can cause chronic and acute disease to workers depending on exposure intensity and frequency. In order to improve the working environment in the livestock facilities, It is important to secure monitoring data of the thermal environment and the concentration of harmful gases and fine dust. Multi-point measurement was performed to analyze the regional environmental conditions in the pig rooms. When analyzing the working environment, video monitoring was conducted to analyze the concentration changes of ammonia, hydrogen sulfide and fine dust according to worker movement and work type. Ammonia and hydrogen sulfide monitoring result showed 1.5~2 times higher concentrations than other work when working in the pigs living zone, and 2~4 times higher than other work when working to increase the activity of pigs. In the case of fine dust, the result was 1.3 times higher than the worker's exposure standard in a specific work. The concentrations of gases and dusts from pig farms are not of concern for acute poisoning in normal work, but there is a risk of chronic respiratory disease if they are continuously exposed. Accordingly, there is a need for development of work environment monitoring device tailored to workers and preparation of alternatives.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.2
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• pp.211-217
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• 2009

This paper proposes a way of expanding the use area of localization technique by using a beacon. In other words, we have developed the auto-calibration algorithm that recognizes the location of this beacon by attaching the beacon on an arbitrary position and by using the information of existing beacon under this situation. By doing so, the moving robot can overcome the limitation that the localization of moving robot is only possible within the area that has installed the existing beacon since the beacon cannot be installed on the accurate location when passing through a danger zone or an unknown zone. Accordingly, the moving robot can slowly move to the unknown zone according to this auto-calibration algorithm and can recognize its own location at a later time in a safe zone. The localization technique is essentially needed in using a moving robot and it is necessary to guarantee certain degree of reliability. Generally, moving robots are designed in a way to work well under the situation that the surroundings is well arranged and the localization techniques of using camera, laser and beacon are well developed. However due to the characteristics of sensor, there may be the cases that the place is dark, interfering radio waves, and/or difficult to install a beacon. The effectiveness of the method proposed in this paper has been proved through an experiment in this paper.

• Journal of Korean Society of Transportation
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• v.31 no.5
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• pp.3-15
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• 2013

The purpose of this study is to propose a methodology for operating variable speed limit (VSL) strategies in freeway work zones. A notable feature in this study is to incorporate a multi-criteria decision making process into deriving better VSL strategies. Decision criteria in this study include operational efficiency, safety, and environmental impacts. Travel speed, acceleration noise, and CO2 were used as performance measures for evaluating VSL strategies. A multi-criteria value function was developed through an analytical hierarchical process (AHP) for representing expert's knowledge. Then, a variety of VSL operations scenarios were investigated utilizing a microscopic traffic simulation suite, VISSIM. The proposed methodology would be useful in supporting more efficient, safer, and more environment-friendly traffic operations and control in freeway work zones.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.1-11
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• 2009

Rapid visualization of flood area of downstream according to the dam effluent in flood season is very important in dam management works. Overlay zone of river bight should be removed to represent flood area efficiently based on flood stage which was modeled in river channels. This study applied drainage enforcement algorithm to visualize flood area considering river bight by coupling Coordinate Operation System for Flood control In Multi-reservoir (COSFIM) and Flood Wave routing model (FLDWAV). The drainage enforcement algorithm is a kind of interpolation which gives to advantage into hydrological process studies by removing spurious sinks of terrain in automatic drainage algorithm. This study presented mapping technique of flood area layer considering river bight in Namgang-Dam downstream, and developed system based on Arcobject component to execute this process automatically. Automatic extraction system of flood area layer could save time-consuming efficiently in flood inundation visualization work which was propelled based on large volume data. Also, flood area layer by coupling with IKONOS satellite image presented real information in flood disaster works.