• The Journal of Sustainable Design and Educational Environment Research
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• v.10 no.1
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• pp.10-25
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• 2011

Area Offices of Education in Korea assign and execute government budget based on the evaluation of school buildings' safety rating and degree of their deterioration. However, it is never easy to estimate the most appropriate investment amount for old buildings under consideration of their service lives and residual values together. A model of estimating optimum investment cost for obsolete school building is developed taking its life cycle cost into account. The model is also applied to six old buildings in five different schools and found that some of the facilities hardly needed further investment and were better to be rebuilt. The study results will be a great beneficial for officers to make right decision on maintaining obsolete school buildings and to maximize tax payers' money.

• Korean System Dynamics Review
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• v.5 no.2
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• pp.125-147
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• 2004

System dynamics model has been developed and computer simulation has been peformed for the evaluation of R&D policy. One of the main results of the basecase scenario is as follows. After simulation of nuclear R&D resource allocation strategies, we discovered that their net benefit value was maximum at 130% nuclear R&D budget case. And after simulation of human resource management strategies and policy research program strategies, we confirmed that it is beneficial to allocate budgets in the early phase for human resources management program and research program for the policy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1221-1224
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• 2004

In this study, we developed a method classifying slice shot during golf practice using backpropagation algorithm. The 144 data based on the backpropagation model(11 inputs, 2 outputs) was used as a learning set and the model was verified based on the extra 50 data in the process to predict a slice shot in golf swing. The results showed 100％ separating rate of learning set and 91.5％ separating rate of verified set. The developed method can be potentially beneficial for the predicting of slice shot in an indoor golf excercise setting without applying any additional equipment.

• International Journal of Fluid Machinery and Systems
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• v.4 no.2
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• pp.229-234
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• 2011

For Lift-type Vertical Axis Wind Turbine (VAWT), it is difficult to evaluate the performance through the scale-model wind tunnel tests, because of the scale effect relating to Reynolds number. However, it is beneficial to figure out the critical value of Reynolds number or minimum size of the Lift-type VAWT, when designing this type of micro wind turbine. Therefore, in this study, the performance of several scale-models of Lift-type VAWT (Reynolds number : $1.5{\times}10^4$ to $4.6{\times}10^4$) was investigated. As a result, the Reynolds number effect depends on the blade chord rather than the inlet velocity. In addition, there was a transition point of the Reynolds number to change the dominant driving force from Drag to Lift.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.24-29
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• 2010

This paper presents a study on the performance of NASA Rotor 37 with the casing grooves based on three-dimensional numerical analysis. Reynolds-averaged Navier-Stokes equations are solved on a hexahedral grid with the shear stress transport model as a turbulence closure model. The governing equations are discretized by a finite volume method. The validation of the numerical results is performed through experimental data for the total pressure ratio and the adiabatic efficiency. The investigation for an axial compressor with a smooth casing and the casing grooves is carried out to compare the performance parameters, for example, surge margin and efficiency, etc. The surge margin is improved in the case of the casing grooves while remarkable improvement of the efficiency is not produced. The result shows that the casing groove is beneficial to expand the operating range of NASA Rotor 37.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.37
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• pp.201-210
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• 1996

Although FMS implementation in Korea is not yet mature, the worldwide empirical data shows the diffusion of FMS is inevitable in near future. As the reletionships between the high capital cost and the relative benefits and advantages are complex to analyse, it is rather beneficial to prepare the effective operation strategies which exploit the FMS flexibility, such as machine loading with alternative routing and dispatching rules. This paper shows the formulation applying a goal programming model for the loading problem with objectives of minimizing the production cost and maximizing the machine utilization, including constraints such as machine tool capacity and demands, etc. A realistic random FMS model is developed for illustration. Since loading and dispatching are a composite of two interdependent tasks, simulation is made to investigate the interactions between the two.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.375-382
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• 2011

The usages of CFD (Computational Fluid Dynamics) which is simulating turbulent flows in CSTRs (Complete Stirrer Tank Reactors) have been reported. Considering model strategies and simulation techniques, this paper is focused on the turbulence models. The results of this study would suggest multiple reference frameworks relevant to rotational flow simulation. Specifically, the analysis of turbulence dissipation rates referred to this study would solve the relevant environmental engineering problem and would be beneficial to the CFD in CSTRs using mechanical mixer.

• Architectural research
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• v.8 no.2
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• pp.27-36
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• 2006

Structural uncertainties are generally modeled using probabilistic approaches in order to quantify uncertainties in behaviors of structures. This uncertainty results from the uncertainties of structural parameters. Monte Carlo methods have been usually carried out for analyses of uncertainty problems where no analytical expression is available for the forward relationship between data and model parameters. In such cases any direct mathematical treatment is impossible, however the forward relation materializes itself as an algorithm allowing data to be calculated for any given model. This study addresses a new method which is utilized as a basis for the uncertainty estimates of structural responses. It applies double uniform random numbers (i.e. DURN technique) to conventional Monte Carlo algorithm. In DURN method, the scenarios of uncertainties are sequentially selected and executed in its simulation. Numerical examples demonstrate the beneficial effect that the technique can increase uncertainty degree of structural properties with maintaining structural stability and safety up to the limit point of a breakdown of structural systems.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.616-623
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• 2003

Competition among electric generation companies is a major goal of restructuring in the electricity industry, The trading system in an electricity market has been one of the most important issues in deregulated electricity market. This paper deals with comparisons of the major two types of the trading system: compulsory pool market and bilateral contract market. The two trading systems are compared quantitatively from the viewpoint of consumer's surplus and social welfare, This paper, also, proposes a unified model of Cournot and Bertrand for analyzing the mixed trading system of pool market and bilateral contract market. Nash equilibrium of the unified model is derived by criteria for participating in bilateral contract market. Numerical results from a sample case show that a mixed trading system of pool market and price-competitive bilateral market is beneficial to consumer from the view points of consumer's surplus.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.264-269
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• 2009

Marginal Loss Factor(MLF) is represented as the sensitivity of transmission loss, which is computed from the change of the generation at slack bus by the change of the load at the arbitrary bus. The MLF dependent on the selection of slack bus is one of the key factors affecting nodal pricing, Genco's profits, social welfare(SW) and Nash Equilibrium in a competitive electricity market. This paper addresses the methodology of slack bus selection by using Cournot model of Cost Based Pool market. Numerical results from sample cases show that the slack bus of MLF of the highest average is beneficial from the view points of SW.