• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.70-73
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• 2002

Utilities are trying to install the equipment of high quality to avoid deterioration of supply reliability. In addition, many sectionalizing switches which can decrease the total outage value for a fault are installed for the same reason. Therefore, utilities are interested in standards and criteria for installing switches to optimize the total cost on distribution systems. The affect of sectionalizing switches installed on distribution feeder is gradually decreased because the failure rate on distribution feeder is decreased. Also the automation for distribution systems is widely applied for the efficient operation. Therefore, the renewal for installation standards of sectionalizing switches is required to reflect the current operation situation. The variable data is used to consider the KEPCO's real situation of distribution feeder as follows; the feeder capacity, connecting rate, feeder length, failure rate of distribution feeder, the failure rate of switches, perception time of feeder fault, the restoration time for a faulted section, the transfer time to other feeders, and the switching time. In this study, We propose equations which can determine the number of sectionalizing switches for minimizing the outage and switch installation cost.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.227-235
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• 2000

Background and Purpose : Medical and Neurological complications in patients with acute stroke may affect their prognosis including death rate, function and admission period. Some of these complications may be preventable. But few data exist regarding complications occurring in the first weeks. So we sought to observe the type, timing, and frequency of complications in hospitalized patients after stroke. Methods : We retrospectively examined the case notes of patients admitted in Won Kwang Oriental Medical Hospital after stroke. Two observers inspected the case notes using predifined diagnostic criteria and recorded the type, timing, and frequency of complications that occurred during the inpatient period. Results : Complications were recorded in 43 patients(82.7%). The most common medical complications were constipation(25.0%) and shoulder pain(21.2%). The most frequent serious medical problems were pulmonary infection(9.6%) and UTI(7.7%). The most common neurological complications were insomnia(34.6%) and dysphagia(23.7%). The most frequent serious medical problem was mental deterioration(7.7%). Conclusion : Complications after acute stroke are common. There were more medical complications than neurological complications. So we should compile much knowledge about medical complications and treat them actively. The differences between our study and previous studies are attributable to the different methods including patient selection and diagnostic criteria.

• Journal of Korea Water Resources Association
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• v.50 no.10
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• pp.673-679
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• 2017

In this paper a method for estimating the 'service life' and 'residual life' of a water pipe based on the Water Pipe Network Performance Evaluation(WPNPE) results of Water Supply Technical Diagnosis was developed for efficient maintenance of water pipes. The residual life of a pipe was defined as the difference between the service life and elapsed time since installation. The service life was defined as the time when a pipe reaches the reference score for determining deteriorated pipes that was used in the WPNPE. The pipe evaluation criteria and deterioration scores used in the WPNPE for the case study area were considered as independent variables in the multiple regression model for estimating the service life and residual life of the pipes in the area. To estimate the service life for the pipes the reference scores for determining deteriorated pipes were used as the values of the variables that represent the deterioration scores in the constructed regression models. Subsequently, the statistics of the service life and residual life of the pipes in the case study area were presented and analyzed in comparison with the service life defined by the Local Public Enterprizes Act.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.312-313
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• 2018

As global climate change leaded to extensive natural disaster and radical deterioration of infrastructures, there was increased attentions for the evaluation of infrastructures. After the collapse of Seongsu Bridge in 1994, Korea has enacted the "Special act on safety and maintenance of facilities" and secured the safety of facilities using systematic and periodic safety inspections. However, current facility inspections are mainly performed by the physical defect and structural analysis, and do not properly consider the serviceability of infrastructure such as capacity of facility and user's satisfaction. Thus, the purpose of the study is to develop an evaluation criteria for serviceability of infrastructures and finally leading to the revision of "Special Act on safety and maintenance of facilities in rational manner.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.174-175
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• 2014

A Rural house in Chungcheong area have been variety of matters, rapid deterioration of house and incomplete of maintenance control, that is represented lack of durability heating from lack of heat insulation property, health worsening form use of toxic substance and so on. For farmers who did not know where to repair and how to repair, they are urgently needed measures of standard and basis that is to realize a condition of rural house. Accordingly, this study drew major matters and priority for revitalization through analysis of type of rural house from research on the actual condition in order to develope of diagnostic criteria of rural house.

• Journal of Forest and Environmental Science
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• v.7 no.1
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• pp.43-61
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• 1990

The modem society has increased the needs for both public benefits of forests and the economic functions of forest products. The increased public interest and concern for forests have been resulted from rapid growth of urban population, high industrialization, deterioration of environment, and etc. It is essential to evaluate the productive and environmantal functions of forests with a scientific criteria. The purpose of this study is to introduce the scientific evaluation method of such functions of forests, and to discuss its uses and limitations.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.53-54
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• 2015

As the result of uniaxial compression strength test on the CLMS mixing BFS and SS with BFS 4000, it required to determine the desired strength through increasing unit quantity of cement in mixing process because of dramatic strength deterioration of strength according to increasing replacing rate. In this study's result, regardless of differences in fine aggregates used, in order to get uniaxial compression strength in the scope exceeding criteria of minimum strength for applying to the field, the most reasonable combination was to mix replacing BFS with fineness of 6000 in 30%. For the CLMS mixing BFS and SS, in order to improve flow ability by securing quantity of minimum unit and to repress bleeding rate with securing uniaxial compress strength considering the field applicability, regardless of differences in fine aggregates used, to mix BFS over 6000 in 30% was most effective.

• International Journal of Concrete Structures and Materials
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• v.7 no.4
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• pp.265-271
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• 2013

Prestressed concrete cylindrical pipe (PCCP) has been widely used for the distribution of water in communal, industrial, and agricultural systems for a long time. However, as it deteriorates, structural failures have been experienced. Replacing the entire existing PCCP with partial damages is not an economical method. Currently, as a cost effective repairing method, a new approach using fiber reinforced polymer (FRP) has been applied. A new design procedure of this method was proposed considering various kinds of loading condition. However, it is not easy to apply this method for design purpose due to its complex procedures. The objective of this study is to provide a new design criteria and process for PCCP rehabilitation with FRP. Through this method, the appropriate quantities of FRP layers will be decided after examining of limit states of deteriorated PCCP. For this purpose, two deterioration conditions are assumed; fully deteriorated and partially deteriorated. Different limit states for each case are applied to decide the quantities of attached FRP. The concept of "margin of safety" is used to judge whether the design results are within the optimal ranges to satisfy all limit states.

• Journal of the Korea Institute of Building Construction
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• v.9 no.3
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• pp.109-116
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• 2009

The magnesium sulfate solution digestion test carried out for resistance of concrete containing waste glass powder on magnesium sulfate attack. Moreover, it yielded S.D.F index was used for the criteria of quantitative assessment to the resistance of magnesium sulfate for the purpose of evaluation of chemical deterioration on concrete. Furthermore, to evaluate for micro-cracks within concrete and external corrosion, the weight variation of specimens and the dynamic elasticity were compared and analyzed and also the applicability was examined using the analysis of product of hydration through out observing external deformation and micro-structural deformation.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.26-33
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• 2007

Finite element simulation of elastic wave propagation in a concrete plate was carried out to investigate its modeling and damage detection procedures. For the numerical stability three criteria were introduced and tested. With a proper element size and time increment, two different kinds of damage scenarios (crack and deterioration) were applied to verify the feasibility of the finite element simulation. It is shown that the severities of those damages are sensitive to the received displacement signals.