• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.283-288
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• 1996

Core support barrel (CSB) assembly is one of the most important reactor internals structures supporting and protecting the nuclear core during normal operation and faulted events. For Yonggwang 3 and 4 (YGN 3&4), the adequacy of the analytical response prediction of reactor internals for flow induced vibration was demonstrated through the comprehensive vibration assessment program (CVAP) performed during hot functional test. Besides, the vibration characteristics of the CSB of operating nuclear power plant can be examined via the excore neutron noise monitoring signal. In this paper data from YGN 4 analyses, CVAP, and neutron noise monitoring system are compared and evaluated. In general, the results are comparable each other and conservative enough to ensure sufficient design margin and structural integrity. Further investigations on the modelling and analyses procedure are recommended to utilize the experimental results to the maximum extent. And collection of the neutron noise data is desired to serve as a baseline information.

• Journal of Engineering Education Research
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• v.23 no.5
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• pp.61-67
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• 2020

In the associate degree curriculum of the department of mechanical engineering, the results of the study are presented on the structure and content of a subject based on the case-based learning method. As an case, equipment called a laminator that is actually used in the manufacturing site was selected. Class deals with specific engineering issues at each stage of laminator manufacturing (design-machining-assembly-measurement-maintenance) in connection with general engineering topics in prerequisites in the curriculum. Topics include tolerance fit, length measurement, assembly practice, measurement design and statistics of machine maintenance, etc. Courses that apply the case-based learning method may be included in the curriculum as complementary roles to those that apply other student-centered learning method.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.108-114
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• 2000

The work posture impose additional stress upon human workers so that it should be carefully considered in designing works. However, we have a lot of manufacturing plants which convert their standing workplace to sedentary one. To confirm the validity of that trend, the authors conducted an experimental study, and compared the results. The results of the EMG and the self-cognitive symptoms, in general, showed a correspondent trend that the sedentary work posture was rated more comfortable. At the beginning of the work, complaint of the lowerback was higher whereas that of the lower leg and the feet went higher as the time elapsed. If the weight of workpiece were heavier than 500g, increasing rate of bodily discomfort in the sedentary posture were greater than that of the standing posture. In the meanwhile, the standing posture was consistently superior to the sedentary posture in its performance. Thus, in conclusion, for a light assembly work, sedentary work posture would be recommendable because bodily discomfort would be larger irrespective of the small increase of performance increase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.644-652
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• 2018

This paper describes the conceptual design of a customized gripper for the assembly process of IT products, which has a relatively short and regular product replacement cycle. The grippers that are used in the manufacturing field are mostly composed of one to two degrees of freedom and they can only handle one object, not multiple ones. Cost is also an important factor. If it were possible to develop a gripper suitable for the assembly process quickly and easily, some of the difficulties involved in its automation caused by the frequent changes of product and process could be solved. The assembly process utilized for this research is defined and described as the procedure and method of the process analysis due to the confidentiality of the manufacturer. We used an axiomatic design to derive the functional requirements and design parameters of the gripper used for the tablet PC assembly process. We proposed a design method for the conceptual design of the gripper by determining these parameters. For the feasibility study, a specific process was selected and the progress of the gripper design was described as an example. Although there have been studies on the design guidelines for grippers, their considerations are too general and their degree of freedom is too high. This paper defines the function of the gripper based on the assembly process of the IT products, which allows their production to be streamlined and automated. In this research, we attempted to produce a design that reflects the assembly process, not just one that enables objects to be held.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.319-324
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• 2003

In general industrial rotating machinery is operated under 3,600 rpm as rotating speed and designed to have critical speed that is above operating speed. So, there was no problem to operate rotating machine under critical speed. But nowadays, they should be operated more than the frist critical speed as usual with the trend of high speed, large scale and hish precision in industries. In case of the large rotor assembly as the trend of large scale, using fitting method of disk or cylinder on shaft is rising for the convenience of assembly and cutting down of manufacturing cost. The shrink fitting is used to assemble lamination part on shaft for manufacturing of rotor of motor or generator in many cases and also is widely used for other machinery. In rotating system, which is compose of rotor and bearing, the critical speed is determined from inertia and stiffness for the rotor and bearings. In case of fitting assembly, analysis and design of the rotor is not easy because the rotor stiffness is determined depend on a lot of factors such as shaft material/dimension, disk material/dimension and assembled interference etc. Therefore designer who makes a plan for hish-speed rotating machine should design that the critical speed is located out of operating range, as dangerous factors exist in it. In order to appropriate design, an accurate estimation of stiffness and damping is very important. The stiffness variation depend on fitting interference is a factor that changes critical speed and if it's possible to estimate it, that Is very useful to design rotor-bearing system. In this paper, the natural frequency variation of the rotor depends on fitting interference between basic shaft and cylinder is examined by experimentation. From the result, their correlation is evaluated quantitatively using numerical analysis that is introduced equivalent diameter end the calculation criteria is presented for designer who design fitting assembly to apply with ease for determination of appropriate interference.

• Korean Journal of Legislative Studies
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• v.15 no.2
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• pp.159-185
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• 2009

This study aims to examine whether committee preference and negotiation group affiliation have an effect on proposals and passages of legislators' bills. Previous studies points out predominances and reflections of partisan interests, but analytic result shows legislators' preferences work on introductions and passages of bills through committee and negotiation group as assembly institutions. The rates of proposals and passages were high in the committee that legislators would like to belong to. The same result was found in negotiation group affiliation. However, active activities of legislators works in only their committees, not in a general meeting. This result shows that committee and negotiation group are significant institutions of national assembly.

• Design Convergence Study
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• v.14 no.4
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• pp.133-150
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• 2015

In this study, we proposed Interactive Visualization methods that can be analyzed relations between nations in various viewpoints such as period, issue using total 5211 of the UN General Assembly voting data.For this research, we devised a similarity matrix between nations and developed two visualization method based similarity matrix. The first one is Network Graph Visualization that can be showed relations between nations which participated in the vote of the UN General Assembly like Social Network Graph by year. and the second one is Proximity based Circular Visualization that can be analyzed relations between nations focus on one nation or Changes in voting patterns between nations according to time. This study have a great signification. that's because we proposed Proximity based Circular Visualization methods which merged Line and Circle Graph for network analysis that never tried from other cases of studies that utilize conventional voting data and made it. We also derived co-operatives of each visualization through conducting a comparative experiment for the two visualization. As a research result, we found that Proximity based Circular Visualization can be better analysis each node and Network Graph Visualization can be better analysis patterns for the nations.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.04a
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• pp.1-3
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• 1983

The General Assembly of the UN has proclaimed the year 1983 world Communications Year, Development of Communications Infrastructures, with the International Telecommunication Union serving as the lead agency for the year. Therefore, Author investigate the purpose and background of WCY83 and its programs by ITU. As the result, those international plans to implement effectively WCY83 are highly reputed to be reasonable. On this Occassion, I review the current problems refferring to communications policies in Korea and suggest some proposals from the view point of its legislations in order to stimulate the development of communications Science.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.61.6-61
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• 2001

In this paper, we propose a method to analyze measured data from 3D Laser tracking system and to enhance precision performance of a Cartesian robot. Position data are obtained over the stroke of a Cartesian robot with variable speeds. The measured data is need to model errors with several different sources. In general, the error is a function of part accuracy, assembly accuracy, temperature, and control etc. After the sources of errors are identified, they are used to enhance precision performance. The proposed method is more complete than others because we use very accurate 3D Laser tracking system.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.47-54
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• 2000

In general, computer industry is known as clean sector, but computer is a complicated assembly which is highly hazardous substances such as lead, cadmium, mercury, Hexavalent chromium, plastics etc. This paper was presented the quantity of hazardous substances in the personal computer and the problem of its disposition-incinerating, landfilling, recycling. Also EPR which is the solution of e-waste was introduced.