• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.147-179
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• 2002

The important role of observational method in geotechnical engineering are emphasized together with the direction of future development, concerning successful application of the technique on the site investigation, design and feed back at various construction stages. Case histories on the application of feed back are introduced in order to achieve the most economical and reliable construction for tunnel, rock slope and deep excavations through feed back system at design and construction stages. Also the limitations and advantages of the observational method and the role of feed back system are discussed for construction of tunnel, rock slope and deep excavation in hard ground such as layered ground conditions including weathered, soft and hard rocks.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.3
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• pp.109-117
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• 2002

High accuracy of the load forecasting for power systems improves the security of the power system and generation cost. However, the forecasting problem is difficult to handle due to the nonlinear and the random-like behavior of system loads as well as weather conditions and variation of economical environments. So far. many studies on the problem have been made to improve the prediction accuracy using deterministic, stochastic, knowledge based and artificial neural net(ANN) method. In the conventional load forecasting method, the load forecasting maximum error occurred for the holidays on Saturday and Monday. In order to reduce the load forecasting error of the daily peak load for the holidays on Saturday and Monday, fuzzy concept and linear regression theory have been adopted into the load forecasting problem. The proposed algorithm shows its good accuracy that the average percentage errors are 2.11% in 1996 and 2.84% in 1997.

• Smart Structures and Systems
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• v.15 no.3
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• pp.609-625
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• 2015

Management of infrastructure stock is essential in sustainability of society, and its analysis and optimization are studied in the light of control system modeling in this paper. At the first part of the paper, cost of stock management is analyzed based on macroscopic statistics on infrastructure stock and economical growth. Stock management burden relative to economy is observed to become larger at low economic growth periods in developed economies. Then, control system modeling of stock management is introduced and by augmenting maintenance actions as control input, dynamic behavior of stock is simulated and compared with existing time history statistics. Assuming steady state conditions, applicability of the model to cross sectional data is also demonstrated. The proposed model is enhanced so that both preventive and corrective maintenance can be included as system inputs, i.e., feedforward and feedback control inputs. Optimal management strategy to achieve specified deteriorated stock level with minimal cost, expressed in terms of preventive and corrective maintenance actions, is derived based on estimated parameter values for corrosion of steel bridges. Relative cost effectiveness of preventive maintenance is shown when target deteriorated stock level is lower.

• Structural Engineering and Mechanics
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• v.56 no.5
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• pp.745-765
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• 2015

This paper presents the design of reinforced concrete combined footings of trapezoidal form subjected to axial load and moments in two directions to each column using a new model to consider soil real pressure acting on the contact surface of the footing; such pressure is presented in terms of an axial load, moment around the axis "X" and moment around the axis "Y" to each column. The classical model considers an axial load and moment around the axis "X" (transverse axis) applied to each column, and when the moments in two directions are taken into account, the maximum pressure throughout the contact surface of the footing is considered the same. The main part of this research is that the proposed model considers soil real pressure and the classical model takes into account the maximum pressure, and also is considered uniform. We conclude that the proposed model is more suited to the real conditions and is more economical.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.2
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• pp.19-27
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• 1984

An extension of the finite element method to the stability analysis of shells of revolution under static axisymmetric loading is presented in this paper. A systematic procedure for the formulation of the problem is based upon the principle of virtual work. This procedure results in an eigenvalue problem. For solution, the shell of revolution is discretized into a series of conical frusta. The buckling mode in the circumferential direction is assumed, this assumption makes the problem economical for the computing time. The present method is applied to a number of shells of revolution, under axial compression or lateral pressure, and comparision are made with other theoretical results. The results show good agreement each other. The effects of aspect ratio, boundary conditions and buckling modes on the buckling strength of shells of revolution are studied. Also the optimum shape of cylindrical shell under uniform axial compression is obtained from the view point of structural stability.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.178-185
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• 1999

Minimum life-cycle cost helps to evaluate cost effectiveness of base-isolated bridges under specific condition. Life-cycle cost mainly consists of the initial construction cost and the expected damage cost. Damage cost estimation needs proper model of input ground motion failure probability evaluation method and limit states definition. We model the input ground motion as spectral density function compatible with the response spectra defined at each seismicity and site condition. Spectrum analysis and crossing theory is suitable for reseating calculation of failure probabilities in the process of cost minimization. Limit states of base-isolated bridges re defined for superstructure isolator and pier respectively The method is applied to both base-isolated bridges and conventional bridges under the same conditions to investigate cost effectiveness of base isolation in low and moderate seismic region. the results show that base-isolation of bridges are more effective in low and moderate seismic region and that the site effects on the economical efficiency may not be negligible in such a region.

• Journal of Industrial Technology
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• v.9
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• pp.3-19
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• 1989

Shoreline have been changed from time immemorial continuously, three-quarters of the population of the world live by the sea. It is not too much to say that all of us who live in Han penisular live by coastal zone because we can reach in the beach within only for hours. In this way effectual use and menagement of coastal zone is very importent problems in side of protection of marine resources as well as land use. But it has problems which change of shoreline have to be surveyed and to be predictived. This study the pattern and characteristics of the East sea coast including investigations of the shoreline changes of the East sea. This report gives a description of the method for implementing the seawall boundary condition in the shoreline change numerical model. Such analytical solutions can provide a simple and economical means to make a quick qualitative evaluation of shoreline response under a wide range of environmental and engineering conditions.

• Korean Institute of Interior Design Journal
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• no.29
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• pp.137-144
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• 2001

The purpose of this study was to suggest the design guidelines for healthcare facilities for the elderly. D healthcare facility for the elderly in Busan was case studied. Subjects were 34 elderly patients, 35 families, and 36 nurses who were in this facility. The elderly Patients and their families were interviewed and the nurses were answered through self-administered questionnaires. Generally, the users of this facility were positively responded to the building and interior design of this facility. Also, the elderly patients and the families were mere satisfied with the design of this healthcare facility than the nurses. All users responded the functional aspects and the whole interior design of this healthcare facility positively and the environmental psychological aspects negatively Also, the nurses responded this facility's ambient environments negatively and the patients and the families positively. The elderly patients and their families wanted to share the inpatient room with 3-6 persons because of their economical conditions and social contacts. Almost half of them preferred to sit down on the floor Also, they tended to prefer to light interior color, wall papers, and the familiar and home-like environments.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.1
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• pp.9-16
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• 1984

This paper describes the minimum cost expansion planning which is based on the economical aspect under the various conditions on the power system expansion planning. It presents not only linear cost characteristics analysis but also stepwise cost characteristics analysis which satisfies practical condition in the power system. The latter analysis must be handled by integer programming (IP), because the relation between the cost and the capacity has stepwise characteristics. In order to proceed the latter analysis, the solving procedure is illustrated in detais by using branch and bound method which includes the network flow theory and maximum flow-minimum cut theorem.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.125-132
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• 2012

Saemangeum development project is the world's largest tidal flat reclamation project. It is currently under construction, and proceeding with phased developments. The construction of agricultural areas within the Saemangeum reclamed lands is also a part of this project. These areas will have multi-functional complexes aiming to produce mainly eco-friendly horticultural crops and livestock products for the purpose of export. The major concern is to obtain sufficient water with appropriate quality to supply to those areas. The objective of this study is therefore to provide available water supply plans for agricultural purpose, especially for horticulture and livestock complexes. Alternative methods for water supply are purifying water from the Saemangenm lake or using water supply services providing by K-water or local governments. This study investigates to find an economical water supply plan through comparisons of these methods. As a result, the water purification method with Saemangeum lake water could be advantageous for given water supply conditions to horticulture and livestock complexes.