• Journal of Power System Engineering
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• v.20 no.6
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• pp.11-19
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• 2016

A variable speed refrigeration system(VSRS) has been received high attention for energy saving ability. This paper investigates effects of design factors such as membership function range and sampling time to control performances for systematical designing fuzzy logic controller of the VSRS. Some comparisons of control performance between the fuzzy and PI are conducted including comparative evaluation of robustness against noise by using computer simulations. The simulation results showed that the fuzzy is very useful design method for engineers in the industrial fields which have big noises system and deal with inherent nonlinear system like the VSRS.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.445-452
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• 2001

Generally, OPC(ordinary portland cement) is used for grouting in Korea, and bentonite has usually been added to prevent the deposition of cement particles. The dispersion of CB(cement bentonite) grout is influenced by variable factors i.e. water to cement ratio, particle size of cement, kind of bentonite, adding volume, methods of adding, viscosity of CB grout materials and curdling time. Among variable factors, the viscosity of CB grout materials is influenced by the dispersion, and dispersion is improved as increasing the mixing speed. In this paper, described a suitable mixing speed of the High Speed Mixer in field, engineering characteristics of CB grout materials vary with the water to cement ratio and the mixing speed as well as confirming the state of dispersion.

• The Journal of Fisheries Business Administration
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• v.47 no.2
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• pp.1-14
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• 2016

This study applied the Stochastic Frontier Analysis to estimate which independent variable affects to efficiency of aquaculture household. This study used wage and facility scale as input variables, sales volume as an output variable to estimate efficiency. Also, the study used region, species, water quality to estimate technical inefficiency factors of the model. The data used for this study were obtained by the operating costs survey using 1:1 interview method. The study selected translog production model with technical inefficiency term estimated as half-normal distribution. In addition, the study used pearson and spearman correlation coefficient among efficiency estimating models. Also, the study analysed differences among estimated efficiencies through t-test, and showed us 0.1793 in species, 0.4677 between Geojae and Masan.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.105-110
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• 2008

This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

• The Journal of Fisheries Business Administration
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• v.51 no.1
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• pp.67-79
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• 2020

The purpose of this study is to propose a policy improvement plan by analysis of the extinction risk factors reflecting the specificity of fishing villages, fishing village support policies, and settlement conditions of fishing villages as one of the solutions to the immediate problem of fishing village extinction. The results of the study show the higher the level of number of fishing ports, number of returning rural population, and housing diffusion rate, the dependent variable extinction risk index was a positive effect while vacant house ratio and aged house ratio was analyzed to be in was a negative (-) relationship with the dependent variable.The policy implications through this study were to prepare an effective policy to reduce the risk of extinction, to improve urgent settlement conditions, and to prepare a condition to convert returning rural population into fishery population.

• Journal of Families and Better Life
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• v.15 no.4
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• pp.269-286
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• 1997

The purpose of this study is to explore the degree of family strengths in Korea and the relationships of various characteristics to it. Family strengths the dependent variable is composed of four factors such as family commitment family communication family values and family crisis coping strategies. Independent variables are the following :i) family socio-demographic variables ii) individual variables iii) social variables. The main findings were as follows; 1. The degree of family strengths in Korea is generally high. Among four factors of family strengths the degree of family commitment is relatively higher and that of family values is relatively lower than the others. 2. The variables which independently affected the family strengths have influence in the following order ; individual marital satisfaction family's S.E.S(middle) self esteem, instrumental support from society and husband's income(middle level). These results show that the variable related to the family streng hs are multi-dimensional. Accordingly for the purpose of fortifying family in strengths educational programs should be prepared according to multi-dimensional characteristics.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.191-192
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• 2011

The construction projects contain a lot of variables and risk affecting productivity. The duration of the project must be recognized important as for quality, unit cost and safety. There is need for improving work efficiency by investigating relationship of works to prevent delay. This study focuses on analysing the delay factors of steel staircase system to suggest regression model that enables construction productivity estimation. The position of the observers and construction delay factors were expressed by the independent variable of the regression model and productivity was expressed by a dependent variable. This paper suggests quantitative productivity and it is expected that will be helpful estimating application in construction new technologies.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.2
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• pp.94-103
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• 1997

The purpose of this study is to find out the effects of brick paved under-surface soil physical properties which are changed by fixed trampling. Thus, a sandy loam which is known as a profitable soil for plants is used an experimental soil to study the changes of the soil physical properties. It is related to sand bed's thickness & particle size which are settled by experimental variable factors. According to the variation of sand bed's particle size, bulk density and soil hardness at natural dryed soilcondition result in 0.075~2.00mm>2.00~5.00mm>2.00~8.00mm>5.00~8.00mm, and water content at natural dryed soil condition are observed being insensible change rate from the point that sand thickness is 30~40mm and more sand bed's thickness constructed by the variation of sand bed's thickness.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.990-992
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• 1996

The design of I/O scaling factors for fuzzy controller system is proposed in this paper. The proposed method is for nonlinear input scaling factor and variable output scaling factor. The fuzzy controller is evaluated by computer simulation on the 1st order process and 2nd order process. Simulation results showed robust characteristics for variable reference signal.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.208-209
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• 2022

This study aims to analyze the risk factors caused by object damage and third-party damage loss in actual bridge construction based on past insurance premium payment data from major domestic insurers for bridge construction projects, and develop a quantitative loss prediction model. For the development of quantitative bridge construction loss model, the dependent variable was selected as the loss ratio, and the independent variable adopted 1) Technical factors: superstructure type, foundation type, construction method, and bridge length 2) Natural hazards: flood anf Typhoon, 3) Project information: total construction duration, total cost and ranking. Among the selected independent variables, superstructure type, construction method, and project period were shown to affect the ratio of bridge construction losses, while superstructure, foundation, flood and ranking were shown to affect the ratio of the third-party losses.