• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.826-832
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• 2003

This paper presents a new linking methodology of direct load control(DLC) and unit commitment(UC) considering system spinning reserve characteristics. To consider system spinning reserve characteristics, we formulate new constraints. And to link DLC and UC, we employed 3-Dimensional dynamic programming which has DLC state, UC state, and stage. As a result, economical DLC and UC schedule of the power system is possible. This method is applied to the test system, and the usefulness of the method is verified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.31-34
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• 2003

To trace the working point of pressure-fed rocket propulsion system, direct analogy model was suggested, by which propellant mass flow rate and combustion chamber pressure were calculated from propellant tank pressures, levels and flight acceleration. In this paper, the analysis of KSR-III flight test results was taken by example, and it can be described that working point transition tendency of pressure-fed rocket propulsion system can be calculated by this direct analogy model.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.387-394
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• 2004

In the structural analysis procedure using finite element technique, the performance of a linear equation solver is critical because the linear equation solving part spends most of the computing time for finite element analysis codes. However, most of researchers are still using inefficient profile-based direct solvers such as the band solver or the skyline solver. In this research, we introduce the multifrontal solution method as an efficient direct solution method for structural analysis, and show the efficiency and performance of the multifrontal solution method by comparing the performance of our own implementation of the multifrontal method with the band solver or the skyline solver. In addition, we also compare the performance of our solver with other implementations of the multifrontal method such as WSMP and MUMPS as well as commercial structural analysis packages such as ABAQUS and NASTRAN. Through the performance test results, the usefulness and efficiency of our domain-wise multifrontal solver for structural analysis is shown.

• The Journal of the Korean dental association
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• v.13 no.2
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• pp.133-136
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• 1975

The autor studied skin reactions and their incidences among 130 dental students and dentists to 2% Iidocaine HCI, 2% procaine HCI, direct resin, plaster of paris, zinc oxide-eugenol cement, and adhesive plaster by Patch test. The results of the studies are as follows: 1. Eighteen cases out of 130 revealed slight positive reaction toa 1 or 2 allergens. 2. Lidocaine HCL showed 1 case, procaine HCL 4 cases, direct resin 4 cases, Z.O.E. cement 1 case, adhesive plaster 13 case, and plaster of paris showed none. 3. Two delayed reaction were detected after 48 hours, one of which reacted both lidocaine HCL and direct resin, and the other one was a case of adhesive plaster.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.12
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• pp.591-596
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• 2002

This Paper Presents a new methodology for Direct Load Control(DLC) and Unit Commitment. To consider economical effect of DLC, we developed 3-Dimensional dynamic programming which can combine unit commitment and DLC. Traditional dynamic programming has 2-Dimensional which consist of state and stage, but newly developed dynamic programming has DLC state, U.C. state, and stage. As a result, economical DLC and unit commitment schedule of the power system is possible. This method is applied to the test system, and the usefulness of the method is verified.

• Journal of the Korean Home Economics Association
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• v.47 no.7
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• pp.33-43
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• 2009

Depression has a direct relationship with lower quality of life for elderly with cerebral vascular accidents(CVA). Daily hassles worsen depression for elderly with CVA disability and thus an effective intervention is necessary. This research examined the direct influence of daily hassles on depression and the mediation effect of family support among 161 elderly with CVA disability living in Seoul using Structural Equation Modeling. The direct effect of daily hassles on depression was statistically significant (p < .001) while family support was shown to be a mediator between daily hassles and depression. The mediation model of family support was examined using $x^2$ difference and Soble test. As a result, family support was proven to be a partial mediator. Implications are discussed.

• Advances in concrete construction
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• v.8 no.4
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• pp.247-255
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• 2019

Several reinforced concrete structures that get deteriorated by rebar corrosion are retrofitted using Carbon Fiber Reinforced Polymer (CFRP). When rebar comes in direct contact with CFRP, rebar may corrode, as iron is more active than carbon. Progression of corrosion of rebar in strengthened RC structures has been carried out when rebar comes in direct contact with CFRP. The experimentation is carried out in two phases. In phase I, corrosion of bare steel bar is monitored by making its contact with CFRP. In phase II, concrete specimens with surface bonded CFRP were casted and subjected to the realistic exposure conditions keeping direct contact between rebar and CFRP. Progression of corrosion has been monitored by various parameters: Half-cell potential, Tafel extrapolation and Linear Polarisation Resistance. On termination of exposure, to find residual bond stress between rebar and concrete, pull-out test was performed. Rebar in contact with CFRP has shown substantially higher corrosion. The level of corrosion will be more with more area of contact.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.569-581
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• 2000

A cycle simulation program is developed and its predictions are compared with the test bed measurements of a direct injection (DI) diesel engine. It is based on the mass and energy conservation equations with phenomenological models for diesel combustion. Two modeling approaches for combustion have been tested; a multi-zone model by Hiroyasu et al (1976) and the other one coupled with an in-cylinder flow model. The results of the two combustion models are compared with the measured imep, pressure trace and NOx and soot emissions over a range of the engine loads and speeds. A parametric study is performed for the fuel injection timing and pressure, the swirl ratio, and the squish area. The calculation results agree with the measured data, and with intuitive understanding of the general operating characteristics of a DI diesel engine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.149-152
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• 2001

In this paper, aging diagnosis method of CV cable was investigated. CV cable was designed for the sake of using during 30 years. Therefore it was important to evaluate the cable's remaining life because CV cable used for power transmission line since 1970's. CV cable was mainly installed at the underground owing to the environmental condition. If the cable accident occurred, it needs the much time for the accident recovery and the much damage at the industrial activity. therefore, this paper should study the direct leakage current method, a sort of the cables' aging test method

• Journal of Distribution Research
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• v.4 no.1
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• pp.51-69
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• 1999

This study investigates a theoretical background to find the effects of antecedents on postpurchase dissatisfaction behavior. To test hypotheses empirically, 209 questionnaires were collected from customers of Korean retailers in Pusan. The results can be summarized as follows. First, the perceived likelihood of successful complaint, the perceived value of complaint, attitude toward complaining has a direct influence on voice. However, controllability has no significant effect on voice. Second, the controllability has a direct effect on exit but perceived value of complaint has no significant effect. Third, no variables have direct effects on negative word-of-mouth. These findings may reflect the fact that negative word-of-mouth is different from voice and exit in terms of dimensions of postpurchase dissatisfaction behavior.