• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.69-76
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• 2005

The performance of water-to-water heat pump system coupled with the ground source vertical heat exchanger is presented in this paper. The CAP program of Florida Heat Pump Co. is used to predict the heat pump performances while the EED program calculates the borehole fluid temperature. It is shown that COPH increases with decreasing the temperature of output water for the operation of heating mode and COPR increases with increasing temperature of output water for the operation of cooling mode. The value of specific heat extraction rate must be moderate to insure the reasonable installation cost of borehole system. With $1^{\circ}C$decrease of $T_{wo}$ the average COPH increase is estimated as about $0.06/^{\circ}C$(for $T_{wo}\;=\;45{\sim}60^{\circ}C$ range) while with $1^{\circ}C$ increase of $T_{wo}$ the estimation of COPR increase is about $0.13/^{\circ}C$(for $T_{wo}\;= \;5{\sim}11^{\circ}C$ range) at the specific heat extraction rate of 30W/m.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.58-58
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• 2005

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.199-200
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• 2005

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.201-201
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• 2005

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.55-57
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• 2005

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.771-774
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• 2008

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.842-848
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• 2020

Purpose: It is important to operate safely and economically in obsolescent power plant facilities. Economical operation is related in the balance of the supply and demand. Safety operation predicts the possible risks in the facilities and then, takes measures to the facilities. For the monitoring of the power plant facilities, we needs several kinds of the sensing system. From the sensors data, we can predict the possible risk. Method: We installed the acoustic, vibration, electric and smoke sensors in the power plant facilities. Using the data, we developed 3 kinds of prediction models, such as, demand prediction, plant engine abnormal prediction model, and risk prediction model. Results: Accuracy of the demand prediction model is over 90%. The other models make a stable operation of the system. Conclusion: For the sustainable operation of the obsolescent power plant, we developed 3 kinds of AI prediction models. The model apply to JB company's power plant facilities.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.133-144
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• 2004

Pre-reinforcement ahead of a tunnel face using long steel or FRP (Fiberglass Reinforced Plastic) pipes in NATM(New Austrian Tunnelling Method), known as the RPUM(Reinforced Protective Umbrella Method) or UAM (Umbrella Arch Method), is the promising method to sustain the stability of a shallow tunnel face and reduce the ground settlements. In addition, horizontal reinforcing of the face is recently emphasized to improve the stability of the face. However, the characteristics on longitudinal arching around the face have not yet been established quantitatively with the RPUM (crown-reinforcing) and/or the face horizontal reinforcing. In this study, therefore, the behavior of cohesionless soil around the face reinforced by the reinforcing member representing the RPUM and horizontal reinforcing is investigated through two-dimensional laboratory model tests. A series of tests were carried out on various conditions by changing lengths and angles of the reinforcing members. Based on the vertical pressure around the face, the characteristics of longitudinal arching have been found for the case of the non-reinforced and the reinforced.