• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.420-420
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• 2008

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.64.1-64
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• 2001

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1439-1447
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• 1994

Test results of friction-factor for the flow of air in a narrow channel lined with various honeycomb geometries show that, generally, the friction-factor is nearly constant or slightly decreases as the Reynolds number(or Mach number) increases, a characteristic common to turbulent flow in pipes. However, in some test geometries this trend is remarkably different. The friction factor dramatically drops and then rises as the Mach number increases. This phenomenon can be characterized as a "friction-factor jump." Further investigations of the acoustic spectrum indicate that the "friction-factor jump" phenomenon is accompanied by an onset of a normal mode resonance excited coherent flow fluctuation structure, which occurs at Reynolds number of the order of $10^4$. New empirical friction-factor model for "friction-factor jump" cases is developed as a function of Mach number and local pressure.ach number and local pressure.

• Korean Journal of Social Welfare
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• v.52
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• pp.117-141
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• 2003

This study is to identify the efficiency in Busan social welfare agencies between input factors and output factors. For this purpose, gathered are the 2001 services reports of those study agencies. This study used 4 difference model, model 1; comparing input factor(social worker number & labor cost) about output factor(the total number of program used person), model 2; comparing input factor(the total number of social welfare agencies staff & the total working expenses) about output factor(the total number of program used person), model 3; comparing input factor(the total number of volunteer, social welfare agencies staff & a period of operation) about output factor(the total number of program used person), model 4; comparing input factor(the total number of volunteer, social welfare agencies staff, a period of operation & the total working expenses) about output factor(the total number of program used person). Charnes's study(1978) provided an analytical tool for efficiency services output of non-profit organizations, and DEA(Data Envelopment Analysis) was a analytical framework for evaluating the impact of social service outcome. the finding are as follows : (1) In the results of comparing 4 models as same standard, we can find 35-55%(16-25) efficiency agencies among the 45 social welfare agencies. (2) For all DMU becoming the efficiency 1 to standard of output factor, model 1; 33 agencies are increasing the social worker number($\Delta$0.8 number), 10 agencies are raising the labor cost of social worker($\Delta$1,189,000 Won), model 2; 30 agencies are increasing the total number of social welfare agencies staff($\Delta$1.25 number), 14 agencies are raising the total working expenses($\Delta$1,447,000 Won), model 3; 8 agencies are increasing the total number of social welfare agencies staff($\Delta$2.26 number), 14 agencies are increasing the total number of volunteer($\Delta$52 number), and 10 agencies are increasing a period of operation($\Delta$13 month), model 4; 24 agencies are increasing the total number of social welfare agencies staff($\Delta$1.8 number), 12 agencies are raising the total working expenses($\Delta$5,017,000 Won), 12 agencies are increasing the total number of volunteer($\Delta$43.2 number), and 23 agencies are increasing a period of operation($\Delta$16 month).

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.59-66
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• 2021

The earthquakes are the natural disasters that can cause the most serious damage to civil structures. Therefore, various studies are being conducted to secure the safety of structures against earthquakes. Most studies on the safety or mechanism of civil structures during earthquakes are being conducted based on lab scale test, because real structure tests are impossible when considering the scale of civil structures. The scaling factor proposed by Iai is mainly cited, but when applying the scaling factor proposed by Iai, there are many difficulties in selecting the structural members necessary for the production of the lab scale model. This is because when applying the scaling factor proposed by Iai, the scaling factor must be applied to the elastic modulus, which is the material property of the structure. Therefore, a new method based on Iai's 's similarity law for determining scale factor is applied in this study where the material property of real structure is same as that of lab-scale model. Through the results of this study, it is considered that the characteristics of the structure calculated through the lab scale model test can more accurately reflect the characteristics of the real structure.

• Journal of Technology Innovation
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• v.14 no.1
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• pp.177-199
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• 2006

Recently, it has become important to establish a technology appraisal system because of increasing a service of technology credit guarantee. Also, there have been many efforts to evaluate a technology in the advanced countries. The technology/credit appraisal model which can measure firms' performance was suggested by Small and Medium Business Administration. In this paper, we analyze a structural validity of the model by confirmatory factor analysis and estimate the model which can distinguish whether an investment is possible or not by discriminant analysis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.3
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• pp.114-120
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• 1988

A water surface profile computation model using a standard step procedure was developed for gradually varied flow at an irrigation channel network. Flow characteristics ab Banweol district near Suweon were field monitored during irrigation periol of 1987. The model was applied to the main system at the district and the simulation results were compared to the field data. The results are sumrnarized as follows ; 1. The simulated water surface profiles from the model were in good agreement with the measured water surface profiles at different flow rates. 2. The model applicability for defining a stage-discharge relationship at a channel reach was demonstrated with reasonable accuracy when water stage and friction factor were given. 3. The roughness coefficient was found to be a major factor sigrificantly affecting computed water surface profile among a few physical input parameters for the model.

• Asia pacific journal of information systems
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• v.15 no.4
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• pp.109-133
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• 2005

The purpose of this study is to develop and validate a model of firm's IT capability based on IT resources such as IT infrastructure, IT personnel, and IT routine. To do this, the study defined IT capability as a third-order factor model and identified three conceptual dimensions of IT capability: IT infrastructure flexibility, IT personnel expertise, IT resource management capability, IT resource management capability indicates a capacity generated by IT routines, a new IT resource type identified in this study. The validity of the proposed model is evaluated with 243 firm level data using LISREL. The results of confirmatory factor analysis(CFA) demonstrated that the model is highly reliable and valid. Additionally, it was found that IT routines have a high potential as a new IT resource category.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.477-483
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• 2003

An independent kinematic hardening material model in which the reverse yielding point is defined by the Bauschinger effect factor (BEF) , has been defined for stainless steel SUS 304. The material model and the BEF are obtained experimentally and represented mathematically as continuous functions of effective plastic strain. The material model has been incorporated in a non-linear stress analysis for the prediction of reverse yielding in thick-walled cylinders during the autofrettage process of these vessels. Residual stress distributions of the independent kinematic hardening material model at the onset of reverse yielding are compared with residual stresses of an isotropic hardening model showing the significant effect of the BEF on reverse yielding predictions. Critical pressures of direct and reverse yielding are obtained for the most commonly used cylinders and a range of permissible internal pressures for an efficient autofrettaged process is recommended.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.27-40
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• 2006

Today's customer demands in supply chains tend to change quickly, variously even in a short time Interval. The uncertainties of customer demands make it difficult for supply chains to achieve efficient inventory replenishment, resulting in loosing sales opportunity or keeping excessive chain wide inventories. Un this paper, we propose an adaptive vendor managed inventory (VMI) model for a two-echelon supply chain with non-stationary customer demands using the action-reward learning method. The Purpose of this model is to decrease the inventory cost adaptively. The control Parameter, a compensation factor, is designed to adaptively change as customer demand pattern changes. A simulation-based experiment was performed to compare the performance of the adaptive VMI model.