• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1041-1046
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• 2004

A proportional pressure control valve has a nonmagnetic ring which is inserted in between a coil and plunger and it can get attraction force in proportion to input current by an influence of control cone. Therefore, a proportional pressure control valve is applied to a servo system as substitution of servo valve and an on-off solenoid valve widely because control of a high level is possible and pollution level is low. The purpose of this study is to develop domestic model of a proportional pressure control valve, and a test model was designed and manufactured through valve system analysis and finite element analysis. And comparison between results of theoretical analysis and static / dynamic characteristics test were carried out on a manufactured test model, and it was confirmed that it has excellent performance in comparison with other foreign products.

• Spatial Information Research
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• v.10 no.4
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• pp.551-565
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• 2002

To carry out systematic groundwater assessment, exploration and management and to use these for protection of optimal groundwater yield, a data analysis and management system is required. Thus, the object of this research was to develop and apply software that integrates GIS and groundwater modeling: GISGAM (GIS for groundwater analysis and management system). The GIS program ArcView and the groundwater-modeling program MODFLOW were used for the GISGAM. The program components consist of a pre-processor, a processor, and a post-processor for groundwater modeling. In addition, GIS functions such as input, manipulation, analysis and output of data were embedded into the program. In applying the program to pilot area, topography, geology, soil, land use and well databases, and a groundwater flow model were constructed for the study area. This case study revealed the advantage and convenience of groundwater modeling using GIS capabilities. By integrating GIS and the groundwater model, the impact of changing values of hydrogeological constants on model results could be more easily evaluated.

• Earthquakes and Structures
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• v.2 no.1
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• pp.25-42
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• 2011

This paper discusses a mechanical model for the vulnerability assessment of old masonry building aggregates that takes into account the uncertainties inherent to the building parameters, to the seismic demand and to the model error. The structural capacity is represented as an analytical function of a selected number of geometrical and mechanical parameters. Applying a suitable procedure for the uncertainty propagation, the statistical moments of the capacity curve are obtained as a function of the statistical moments of the input parameters, showing the role of each one in the overall capacity definition. The seismic demand is represented by response spectra; vulnerability analysis is carried out with respect to a certain number of random limit states. Fragility curves are derived taking into account the uncertainties of each quantity involved.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1222-1225
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• 1993

The purpose of this paper is to construct a prediction system on the chance of rain in a local region using a fuzzy relational model. The prediction system consists of two parts. One is a prediction part on the chance of rain. The compositional law of fuzzy inference, proposed by Zadeh, is applied to predict the chance of rain. The other is a learning part of a fuzzy relational model using input-output data. A simple and fast learning algorithm is used in this part. Simulations are carried out by the actual weather data in our city and their results show the validity of prediction by the fuzzy relational approach.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.328-332
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• 1993

This study presents an algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is applied for the weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined form the step input. The performance of the algorithm was tested on a check weigher. Discussions were extended to the development of noise reduction techniques and to the lagged introduction of objects on the moving plate. It turns out that the algorithm shows several desirable features suitable for microcomputer assisted real-time signal processing, which are high precision and stability in noisy environment.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.136-142
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• 1994

This study presents an algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is described for te weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined from the step input. The performance of the algorithm is illustrated in digital simulation. Discussions are extended to the development of fast converging algorithm. It turns out that the algorithm shows several desirable features suitable for microcomputer assisted real-time signal processing, which are high precision and stability in noisy environment.

• The Journal of Fisheries Business Administration
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• v.42 no.2
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• pp.15-30
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• 2011

This study is designed to measure the relative efficiency of regional fishery cooperatives based on Data Envelopment Analysis(DEA) methods. Selecting 40 regional fishery cooperatives in Busan as Decision Making Units (DMUs), the study uses their panel data from 2007 to 2008 to rank the relative efficiency of the DMUs. First, the efficiency score of the DMUs are calculated using CCR, SBM, and super-SMB model. Within the model, input variables are the number of employees and area of fishery cooperatives. Output variables are the amount of deposit money, loan and profit. Based on the efficiency scores calculated from super-SMB model, the efficiency ranking of the DMUs is determined. Second, the differences in average efficiency calculated from the three DEA models are tested using a pair-wise mean comparison test. The results based on the efficiency scores evaluated from super-SMB model show that seven out of the forty DMUs are efficient; among the efficient DMUs, the DMUs that can be benchmarked for inefficient DMUs through the frequency analysis of reference set being identified. Third, the differences in average efficiency of the three DEA models between 2007 and 2008 are tested using pair-wise mean comparison test and the study estimates the efficiency change of the DMUs between 2007 and 2008 using Malmquist productivity index(MPI). Finally, the paper suggests an improved composite DMU superior to the inefficient DMUs evaluated by Super-SBM model.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.1
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• pp.33-38
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• 2002

In this paper, a Two-Degree-of-Freedom-Controller(TDFC) for DC motors based on inverse dynamics and the fuzzy technique is presented. The proposed controller includes the inverse dynamic model of a DC motor system, a prefilter and a fuzzy compensator. The model of the system is characterized by a nonlinear equation with coulomb friction. The prefilter eliminates high frequency effects occurring when the inverse dynamic model is implemented. The fuzzy compensator is designed for tracking the change of the reference input and simultaneously regulating the error between the reference input and the system output which can be caused by disturbances. The optimal parameters of both the model and the compensator are identified by a real-coded genetic algorithm. An experimental work on a DC motor system is carried out to verify the performance of the proposed controller.

• Journal of Information Technology Services
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• v.18 no.1
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• pp.63-78
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• 2019

Despite the government's efforts, the jobs in SW industry are not easily created and only many problems of unemployment have been pointed out, failing to solve the basic problem. Sustainable decent jobs were recognized as a national task. Emotional connection between things and people is the SW industry, which is a core industry of the 4th industrial revolution. In order to be globally competitive, SW job creation, manpower planning for generating core human resources and highly educated manpower is a necessary issue. Basic estimation of job creation using the Input Output Table by Bank of Korea has some limitations and did not consider the SW industry characteristics. This study proposes an assessment model of SW policies and the practices a case of assessment of 113 projects supported by the Korean government. We propose a flowchart that can divide the government budgets according to the portion of the direct investment for SW industry by introducing investment types. We use an adjusted Input Output Table for SW industry and the model also considers the effect of SW promotions and regulations effects. This model can be used practically and flexibly by adjusting the SW fusion areas portions. It also considers the characteristics of the project, supporting areas, project size, short-term and long-term types. 113 projects of 'MSIT', 'SMBA' and 'NIPA' were analyzed and classified into 'policy' and 'business' to reflect SW job creation effect model considering domestic SW characteristics. By analyzing the practical data, 47,254 jobs are expected to be created within five years in optimistic cases and 27,211 jobs would be created in pessimistic cases.

• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.173-197
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• 2008

The purpose of this study is to analyse the spill-out effects of logistics industries among Korea, Japan and China. For this purpose, we used an International I/O table made by Asian Economic Institute of Japan, which is made up for 11 countries. At first, we transformed the I/O table for 11 countries into that for 3 countries, and then we applied the Inter-Regional Input Ouput model to find out the spill-out effects of one country's logistics investment to another country's logistics or other industries. The contribution of this study is that this paper has suggested a method how to evaluate a logistics interrelation among 3 countries by way of I/O analysis for the first time.