• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.147-153
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• 1999

An in-process extraction method of the ground surface roughness is a bottle-neck and essential field in conventional machining process. We define the D.A.R.F(Dimensionless Average Roughness Factor) that has a roughness characteristic of ground surface. D.A.R.F include the absolute average and the standard deviation values which are the analytic parameters of the AE(Acoustic Emission) signal generated during the grinding operation. The theoretical equation between the surface roughness and the D.A.R.F has been derived from the linear regressive analysis and verified its availability through the experimentation on the surface grinding machine.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.50-56
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• 2006

Residual gas fraction in a combustion process is very crucial to improve combustion and cyclic variations. Especially, the residual gas fraction is strongly affected by backflow of the residual gas during the valve overlap period in an idle operation. Therefore, it is one of the most interesting that valve timings can affect flow characteristics of gas exchange process, especially during idle operation. This analysis investigates residual gas fraction with respect to valve timing changes which is critical for combustion efficiency and engine performance. Flow characteristics of residual gas by changing intake and exhaust valve timing are calculated by CFD methodology during an idle operation in an SI engine. It is analyzed that retarded EVO and advanced IVO results in the increase of valve overlap period and consequently, residual gas fraction. Futhermore, changes in IVO have stronger effects on variation of residual gas fraction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.6
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• pp.82-90
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• 2019

To reduce emissions of marine pollutants, regulations are being tightened around the world. In the shipbuilding and shipping industries, various countermeasures are being put forward. As there are limits to applying countermeasures to ships already in operation, however, it is necessary for these vessels to use energy efficiently. The sensors installed on ships typically gather a very large amount of data, and thus a big data platform is needed to manage and analyze the data. In this paper, we build a big data analysis platform based on Hadoop and Spark, and we present a method to detect abnormal ship operation using the platform. We also utilize real ship operation data to discuss the data analysis experiment.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.371-378
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• 1996

A prototype of expert system which can support the operation for the municipal waste water treatment plant located at Kyoung-Ki Do, Kwang-ju Kun was developed and tested. This system provides (i) tracking the cause of the problem, (ii) analysis, and (iii) solution Knowledge-base consists of about 100 production-rules for the biological wastewater process, such as bio-reactor and final clarifier. Rules were obtained from the analysis of the problems such as sludge bulking. The system provides stable process control and management and effectively helps inexperienced operators with advanced and standard technologies. Future works will focus to develop a statistical process control model and associate with expert system. The control model can process the operation data statistically; analyze the relationship between affecting factors and control variables; and provide optimum operation parameters.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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• pp.44-51
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• 2018

The purpose of RAM analysis in weapon systems is to reduce life cycle costs, along with improving combat readiness by meeting RAM target value. We analyzed the sensitivity of the RAM analysis parameters to the use of the operating system by using the Markov Process based model (MPS, Markov Process Simulation) developed for RAM analysis. A Markov process-based RAM analysis model was developed to analyze the sensitivity of parameters (MTBF, MTTR and ALDT) to the utility of the 81mm mortar. The time required for the application to reach the steady state is about 15,000H, which is about 2 years, and the sensitivity of the parameter is highest for ALDT. In order to improve combat readiness, there is a need for continuous improvement in ALDT.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.26-32
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• 2008

Middle Route Project, the largest water conveyance system in China delivers the water of Changjiang River to North China. In order to create canal operation simulation system, mathematical models are established based on the analysis of hydraulics about steady flow, unsteady flow, and check gate. By simulating the canal operation behavior, we improved the check gate control algorithm and predicted the change process of water surface and flow profile which is very valuable to actual canal operation.

• Journal of Korean Elementary Science Education
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• v.23 no.4
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• pp.273-278
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• 2004

According to Piaget, children aged 11 are in the middle of concrete operation period and formal operation period. So, it is necessary to adopt the Learning Cycle Model (LCM) which helps students improve their cognitive development. After determining the test for the Science Concept of Matter (SCOM), the experimental group showed higher average than the comparative group in the post-test. In the sound understanding, the experimental group showed higher ratio than the comparative group. And in the ratio of imperfect, wrong understanding and no response, the experimental group was lower than the comparative group. On the questions that were needed the complicated inquiry, many students of both groups still couldn't find the fundamental cause. In forming the scientific conceptualization, there was a meaningful difference (p < .001) after post-test Analysis of Covariance (ANCOVA) with pre-test result. After determining the test for the Test Inquiry Science Process (TISP), the experimental group showed higher average than the comparative group in the post-test. In the category of basic inquiry process which is needed in concrete operation, there was a meaningful difference (p < .05). In the category of unified inquiry process which is needed in formal operation, they showed no meaningful difference (p > .05). Therefore, applying the LCM to the chapter of 'Solution and Dissolving' is more effective on improving the scientific conceptualization and on helping the concrete operation abilities than the teacher centered learning.

• KSBB Journal
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• v.16 no.1
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• pp.11-14
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• 2001

Techniques for protein refolding from inclusion body are discussed in view of its engineering application to large scale protein purification. Among the techniques, dilution and dialysis are mainly utilized due to simple operation. Membrane reactor, gel filtration chromatography, and continuous tank operation are emerging tools for their process-scale possibility in refolding. Reaction engineering approaches could be used to analyze the kinetic behaviour in the process scale refolding reactor. The kinetic analysis is helpful in the optimization of refolding yield in the refolding reactor.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.124-127
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• 1997

A key element in the control of Automated Guided Vehicle Systems (AGVS) is dispatching policy. This paper proposes a new dispatching algorithm for an efficient operation of AGVS. Based on an evolutionary operation, it has an adaptive control capability responding to changes of the system environment. The performance of the algorithm is compared with some well-known dispatching rules in terms of the system throughput through simulation. Sensitivity analysis is carried out varying the buffer capacity and the number of AGVS.

• IE interfaces
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• v.18 no.4
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• pp.465-476
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• 2005

Evolutionary operation is a useful tool for improving full-scale manufacturing process by systematically changing the levels of the process variables without jeopardizing the product. This paper presents a system design for the evolutionary operation software called 'evolutionary optimizer'. Evolutionary optimizer consists of four modules: factorial design, many variables, mixture, and mean/dispersion. Context diagram, data flow diagram and entity-relationship modelling are used to systematically design the evolutionary optimizer system.