• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1513-1516
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• 2003

A crank throw, which is one of the crankshaft part for a large diesel engine is manufactured by closed die forging or open die forging. For the purpose of improvement of productivity the open die forging is usually adopted these days. However it has disadvantage of low yield ratio compare to closed die forging. To overcome this problem, the material properties for hot top and bottom zones of ingot are investigated to utilize them to the product and a modified forging process to reduce the material loss of ingot body through forging analysis according to forging factors(a , R, Ø$\sub$B/, Ø$\sub$D/) is suggested.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.548-552
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• 2015

In this paper, we describe the quadruped walking-control algorithm of the complete full-size humanoid DARPA Robotics Challenge-HUBO (DRC-HUBO) robot. Although DRC-HUBO is a biped robot, we require a quadruped walking function using two legs and two arms to overcome uneven terrains in the DRC. We design a wave-type quadruped walking pattern as a feedforward control using several walking parameters, and we design zero moment point (ZMP) controllers to maintain stable walking using an inverted pendulum model and an observed-state feedback control scheme. In particular, we propose a switching algorithm for ZMP controllers using supporting value and weighting factors in order to maintain the ZMP control performance during foot switching. Finally, we verify the proposed algorithm by performing quadruped walking experiments using DRC-HUBO.

• Ocean Systems Engineering
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• v.8 no.2
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• pp.119-166
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• 2018

The assessment of the potential for the design of marine renewable energy systems is reviewed and the current situation for marine renewable energy is promising. The most studied forms of marine renewable energy are ocean wind energy, ocean wave energy and tidal energy. Wind turbine generators include mostly horizontal axis type and vertical axis type. But also more exotic ideas such as a kite design. Wave energy devices consist of designs converting wave oscillations in electric power via a power take off equipment. Such equipment can take multiple forms to be more efficient. Nevertheless, the technology alone cannot be the only step towards marine renewable energy. Many other steps must be overcome: policy, environment, manpower as well as consumption habits. After reviewing the current conditions of marine renewable energy development, the authors analyzed the key factors for developing a strong marine renewable energy industry and pointed out the huge potential of marine renewable energy.

• Women's Health Nursing
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• v.23 no.2
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• pp.63-77
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• 2017

Purpose: The purpose of this study was to explore essences and meaning in experiences of women who have had spontaneous abortion. Methods: A phenomenological methodology was used for the study. A total of five women with the spontaneous abortion participated in the study. In-depth interviews were done for data collection, and the data were analyzed using Colaizzi's method. Results: Five theme clusters, along with 32 sub-themes and 13 themes. The five theme clusters were: 'Waiting and expecting pregnancy', 'Desire to overcome the spontaneous abortion', 'My baby makes me cry and laugh', 'My precious baby', and 'Want to hear with sympathy and talk with you', Conclusion: The women who have had the spontaneous abortion experiences can prevent potential physical and psychological complications after miscarriage by getting education and intervention in nursing. Moreover, they may experience that negative factors of the spontaneous abortion can be turned into positive things through emotional support of family and medical teams.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1732-1750
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• 2010

Operation of KORAIL's level crossing is in charge of KORAIL. As taking over existing level crossing to KORAIL, they do not conduct risk assessments, so we do not know about any possibilities of inner risk. And present operation of safety of the level crossing is just regular checking of reaction and functions of safety equipments physically, we need to react to the changes of what's going on around of level crossing and incestigation of traffic flow and surrounding conditions more spontaneously. So, we have to prepare the strategies against accidents of level crossing cost-effectively based on regular risk assessments for sustainable safety improvements and overcome operational problems of present level crossing's safety. Here, we're going to investigate the level of safety level and present risk factors of the level crossing using risk assessments for accidents/error of the equipments to show operational strategies of level crossing based on risk assessments.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.38
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• pp.51-60
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• 1996

There is a general challenge offered to the field of engineering economics by the introduction of advanced technologies. A survey of the existing literature on evaluation of advanced information and manufacturing system indicate that the traditional approaches are inadequate for economic evaluation techniques used in its appraisal, difficulty in evaluating the potential benefits and criteria used to assess management performance. In this paper, an attempt has been made to overcome the above deficiencies by presenting an approach to account for the justification and selection of the Local Area Network(LAN) architectures. This is based on the Analytic Hierarchy Process(AHP) and is capable of taking into account many intangible factors as well. The usefulness of the proposed approach is demonstrated through a case situation and sensitivity analysis. Finally, some research directions for future work are identified.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.277-278
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• 2007

Even though high NA, Hyper SIL system easily decline the optical performance even a little alignment error. Not only to overcome this instability but to maintain the high NA gain, we suggest a new system (Optimum SIL) which is a combination of each advantage of Hyper SIL and Hemi SIL. Simulation results shows that Optimum SIL system has much higher tolerance to various performance-lowering factors than Hyper SIL system even with a relatively small NA resignation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1219-1226
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• 2011

This paper proposes a novel approach to building an occupancy grid map using sonar data. It is very important for a mobile robot to recognize and construct its surrounding environments for navigation. However, the grid map constructed by ultrasonic sensors cannot represent a realistic shape of given environments due to incorrect sonar measurements caused by specular reflection. To overcome this problem, we propose an advanced sonar sensor model which consists of distance and shape factors used to determine the reliability of sensor data. Through this sensor model, a robot can build a high-quality grid map. The proposed method was verified by various experiments and showed that the robot could build an accurate map with sonar data in various indoor environments.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.974-978
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• 2013

AVI (Automatic Vision Inspection) systems automatically detect defect features and measure their sizes via camera vision. AVI systems usually report different measurements on the same defect with some variations on position or rotation mainly because different images are provided. This is caused by possible variations from the image acquisition process including optical factors, nonuniform illumination, random noises, and so on. For this reason, conventional area based defect measuring methods have problems of robustness and consistency. In this paper, we propose a new defect size measuring method to overcome this problem, utilizing volume information that is completely ignored in the area based defect measuring method. The results show that our proposed method dramatically improves the robustness and consistency of defect size measurement.

• The Journal of Korean Academic Society of Nursing Education
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• v.3
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• pp.7-25
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• 1997

Using the self-evaluation test proposed by D. Girdano, et al., the psycological, and biological causes and personality factors of the stress of the nursing students of K university in local county are measured and analyzed. As fundamental data to overcome these kinds of stress, the overall stress profiles are proposed. The results of this study are ; 1) The freshman group is very susceptible to the stress due to the behavior type and anxiety-reactive personality. 2) The sophomore group is very susceptible to the stress due to frustration, the behavior type and anxiety-reactive personality. 3) Two groups are not susceptible to the stress due to diet and noise. Since the stress is the multi-dimensional phenomena, it is necessary to reduce these stress that the life style of each Individual students be changed and the curriculm and the teaching methodology in nursing school be developed.