• 수산경영론집
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• 제42권2호
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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.

• 전자공학회논문지B
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• 제32B권10호
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• pp.1286-1293
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• 1995

Modified equivalent lumped element model for square spiral inductors have been derived. This model shows more accurate analysis performance than conventional models, and gives reliable design parameters. And this model is made through comparison among distributed multiple coupled line, numerical analysis and experimental data.

• 대한한방부인과학회지
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• 제19권4호
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• pp.77-92
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• 2006

Purpose : This study is to examine what are the effects of the Woogwiyeum(WGY) on the ovariectomized rat model of postmenopausal osteoporosis. Methods : We devide mice to 3 Group(Sham operated group, control group, WGY treated group) and analyze each serum component. Results : 1. Body weight in control group showed significant increase in comparison with sham, but that in WGY-treated showed no change in comparison with control. 2. The level of serum albumin, ALP in control group showed significant decrease in comparison with sham. That in WGY-treated was decreased in comparison with control. 3. Trabecular bone area as well as trabecular thickness in control group showed significant decrease in comparison with sham. Those in WGY-treated showed significant increase in comparison with control. 4. Osteoclast number and oseoblast surface in control group showed significant increase in comparison with sham. Those in WGY-treated showed significant decrease in comparison with control. Conclusion : WGY has shown to be capable of preventing and curing osteoporosis caused by old-aged and postmenopause.

• Journal of information and communication convergence engineering
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• 제3권3호
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• pp.152-156
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• 2005

Korea-China with the fastest speed Internet Broad Band, has achieved many progresses on Internet shopping. Especially, Korea has made a great effort on comparison website construction. A research prototype design and exploratory analysis are presented to assess success factors and impacts of Korea and China price comparison websites. For different user groups, the relationships between the characteristics of technology and tasks, usage, and organizational impacts were analysed. It shows us how to improve the applicability of fit-viability of the price comparison web sites in China after analysis. These results indicate a need for simple but highly functional price comparison applications. And we designed a sample model to include an interactive web service system for price comparison sites that complement existing information systems. This paper provides a basis for further research aiming to improve the design and management of business applications based on emerging technologies of web service and browser for information management.

• 대한기계학회논문집A
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• 제29권2호
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• pp.270-276
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• 2005

This paper develops the flexible computational model of a heavy truck by interfacing the frame modeled as a flexible body to the heavy truck's computational model composed of rigid bodies. The frame is modeled by the finite element method. Three torsional modes and three bending modes of the frame are considered for the interface of the heavy truck's computational model. The actual vehicle test is conducted off road with a velocity of 20km/h. The vertical accelerations at the cab and front axle are measured in the test. For the verification of the developed computational model, the measured vertical acceleration profiles are compared with the simulation results of the heavy truck's flexible computational model. E grade irregular road profile of ISO is used as an excitation input in the simulation. The verified flexible computational model is used to compare the vibration characteristics of a front suspension system having a multi-leaf spring and that having a tapered leaf spring. The comparison results show that the front suspension having a tapered leaf spring has a higher vertical acceleration at the front axle but a lower vertical acceleration at the cab than the suspension system having a multi-leaf spring.

• 한국물환경학회지
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• 제30권2호
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• pp.159-165
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• 2014

Vegetative Filter Strip (VFS) is one of effective Best Management Practices (BMPs) to prevent sediment-laden water problem, is installed at the edge of source area such agricultural area so that sediment occurred in source area is trapped by VFS before it flow into stream or river. Appropriate scale of it needs to be simulated before it is installed, considering various field conditions. In this study, a model using VFSMOD-w model and Genetic Algorithm to determine effective VFS length was developed, it is available to calibrate input parameter related to source area sediment yield through thousands of VFSMOD-w simulations. Useful DBs, moreover, are stored in the model so that very specific input parameters can be used with reasonable values. Compared simulated values to observed data values for calibration, R2 and Nash-Stucliffe model efficiency coefficient were 0.74 and 0.65 in flow comparison, and 0.89 and 0.79 in sediment comparison. The model determined 1.0 m of Filter Length, 0.18 of Filter Slope, and 0.2 cm of Filter Media Spacing to reduce 80% of sediment by VFS. The model has not only Auto-Calibration module also DBs for specific input parameters, thus, the model is expected to be used for effective VFS scale.

• 한국지진공학회논문집
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• 제23권4호
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• pp.231-238
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• 2019

A conventional lumped-mass stick model is based on the tributary area method to determine the masses lumped at each node and used in earthquake engineering due to its simplicity in the modeling of structures. However the natural frequencies of the conventional model are normally not identical to those of the actual structure. To solve this problem, recently an updated lumped-mass stick model is developed to provide the natural frequencies identical to actual structure. The present study is to investigate the seismic response accuracy of the updated lumped-mass stick model, comparing with the response results of the shaking table test. For the test, a small size four-story steel frame structure is prepared and tested on shaking table applying five earthquake ground motions. From the comparison with shaking table test results, the updated model shows an average error of 3.65% in the peak displacement response and 9.68% in the peak acceleration response. On the other hand, the conventional model shows an average error of 5.15% and 27.41% for each response.

• Tribology and Lubricants
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• 제39권3호
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• pp.118-122
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• 2023

In our study, we develop a finite element model based on Archard's wear law to predict the cumulative wear and the evolution of the tool profile in friction stir welding (FSW) applications. Our model considers the rotational and translational behaviors of the tool, providing a comprehensive description of the wear process. We validate the accuracy of our model by comparing it against experimental results, examining both the predicted cumulative wear and the resulting changes to the tool profile caused by wear. We perform a detailed comparison between the predictions of the model and experimental data by manipulating non-dimensional coefficients comprising model parameters, such as element sizes and time increments. This comparison facilitates the identification of a specific non-dimensional coefficient condition that best replicates the experimentally observed cumulative wear. We also directly compare the worn tool profiles predicted by the model using this specific non-dimensional coefficient condition with the profiles obtained from wear experiments. Through this process, we identify the model settings that yield a tool wear profile closely aligning with the experimental results. Our research demonstrates that carefully selecting non-dimensional coefficients can significantly enhance the predictive accuracy of finite element models for tool wear in FSW processes. The results from our study hold potential implications for enhancing tool longevity and welding quality in industrial applications.

• Korean Journal of Hydrosciences
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• 제6권
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• pp.23-37
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• 1995

In this experimental paper, the maximum scour depth at pier was student. The model of the pier of San Gye bridge in the Bocheong stream was set for the experimental studies. Several model verification processes were conducted through the roughness comparisons between model and prototype, pursuing scour depth variations with time depending upon channel bed variation, the comparison of the ratios between falling velocities and shear velocities in the model and prototype, and the comparison of pier scour depths between experimental data and field measuring data. The experiments were conducted in the free flow conditions and pressure flow conditions. The maximum scour depth at piers in the pressure flow conditions is almost twice as much as compared to the free flow conditions. Also, the maximum scour depth variations are indicated in the figures based on the Froude numbers, opening ratios, water depths and approaching angles in the free surface flow conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.27-29
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• 2005

Using a generalized regression neural network, etch microtrenching was modeled. All neurons in the pattern layer were equipped with multi-factored spreads and their complex effects on the prediction performance were optimized by means of a genetic algorithm. For comparison, GRNN model was constructed in a conventional way. Comparison result revealed that GA-GRNN model was more accurate than GRNN model by about 30%. The microtrenching data were collected during the etching of silicon oxynitride film and the etch process was characterized by a statistical experimental design.