• Journal of Welding and Joining
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• 제27권2호
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• pp.57-62
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• 2009

This research was carried out to improve the productivity in the subassembly process of shipbuilding through optimal work planning for the shortest work time. The work time consist of welding time, moving time of gantry, teaching time of robot and robot motion time. The shortest work time is accomplished by even distribution of work and the shortest welding sequence. Even distribution of work was done by appling the simple algorithm. The shortest work sequence was determined by using GA. The optimal work planning decreased the total work time of the subassembly process by 4.1%. The result showed the effectiveness of the suggested simple algorithm for even distribution of work and GA for the shortest welding sequence.

• 산경연구논집
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• 제6권3호
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• pp.19-25
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• 2015

Purpose - The intent of this research is to discover the factors that enhance innovative work behaviors of group members in order to strengthen the competitiveness of small enterprises. In addition, we verify that employee job characteristic factors have an influence between antecedent variables and dependent variables in the work situations at small companies. Research design, data, and methodology - This study is focused on identifying the factors, such as self-efficacy, leader member exchange (LMX), and collective efficacy, which promote innovative work behaviors. A total of 305 valid questionnaires were collected. Results - The results of a path analysis showed that LMX did not have significant effects on task significance, and autonomy did not have significant effects on innovative work behavior. Conclusions - These findings of the study imply that even though leaders supported the groups in accordance with official procedures by placing group members within or outside certain groups, task identity perceived by group members was not impacted. In addition, autonomy given to those with relatively less capability might be a burden rather than a positive outcome.

• 통합자연과학논문집
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• 제14권3호
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• pp.123-129
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• 2021

This research examines the effect of positively skewed population distribution on the two sample t-test through simulation. For simulation work, two independent samples were selected from the same chi-square distributions with 3, 5, 10, 15, 20, 30 degrees of freedom and sample sizes 3, 5, 10, 15, 20, 30, respectively. Chi-square distribution is largely skewed to the right at small degrees of freedom and getting symmetric as the degrees of freedom increase. Simulation results show that the sampled populations are distributed positively skewed like chi-square distribution with small degrees of freedom, the F-test for the equality of variances shows poor performances even at the relatively large degrees of freedom and sample sizes like 30 for both, and so it is recommended to avoid using F-test. When two population variances are equal, the skewness of population distribution does not affect on the t-test in terms of the confidence level. However even though for the highly positively skewed distribution and small sample sizes like three or five the t-test achieved the nominal confidence level, the error limits are very large at small sample size. Therefore, if the sampled population is expected to be highly skewed to the right, it will be recommended to use relatively large sample size, at least 20.

• 펄프종이기술
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• 제32권5호
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• pp.26-43
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• 2000

It is well accepted that gloss variation deteriorates the print quality and there are various objective ways to measure this. Several studies now have shown that the coefficient of variation in the octave band passed printed gloss image has an excellent correlation with ratings by an expert panel using a magnitude estimation scaling method. The correlation improves when the gloss level is also taken into account beyond that of the COV. There is also evidence that the correlation would improve even more if the gloss spatial distribution could be better accounted for. We show that much (at least 80% and perhaps up to 90%) of the gloss distribution can be accounted for by the paper topography over a wide range of dimensions (scale). Recent work has supported the role that microroughness and multiple surface scattering play in the gloss distribution. This offers the promise of showing that even a greater amount of gloss variationcan be explained by topography.

• 연구윤리
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• 제1권1호
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• pp.23-28
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• 2020

Purpose: Focusing on Supreme Court precedents, we intend to establish criteria for judging research misconduct. Research design, data and methodology: In addition, I would like to propose the criteria for judging research misconduct by the KODISA, which applies the court's standards well in practice, and guidelines for preventing research misconduct. Research design, data and methodology: After classifying the case of research misconduct into six cases, the court's judgment and practical application will be reviewed. Results: First, research misconduct that has passed the disciplinary prescription can be punished. This is because the state of illegality continues to this day. Second, even if there were no punishment regulations at the time of research misconduct, it can be retroactively punished with the current punishment regulations. This is because research ethics is a universal and common standard and does not change. Third, if there is a fact that infringes on intellectual property rights, it is presumed unwritten intentions. Therefore, the act of taking and using the work of another person without permission or proper citation procedure, even if it is unintentional and for the public interest, is a research misconduct. Fourth, if there is an inappropriate citation notation, the intention of research misconduct is presumed. It is the judgment of the court that even if a quotation is marked, if it is incomplete, it is recognized as plagiarism. Fifth, if the author uses the work of another person without proper source indication, it is plagiarism even if the other person who owns the copyright agrees to it. The understanding or consent of some parties does not justify research misconduct in violation of public trust. Sixth, it is a research misconduct to create a new work without citations for one's previous work. In addition, even if there is a citation, if the subsequent writing is not original, it is a research misconduct. Conclusions: Academia should clarify the scope of research misconduct by referring to the Research Ethics Regulations of KODISA, and deal with research results that lack the value as creative works similar to those of research misconduct.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.407-413
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• 2003

Before expanding of distribution automation application to distribution network, we must examine whether there are economical effect. Investment expense for distribution automation can be divided into facility investment expense, maintenance expense, communication expense, investment expense etc. Effect of distribution automation can classify by effect that can convert into money and effect that can not convert into money. Representative effect is outage time decrease effect, distribution line loss decrease effect, main transformer upload effect, distribution line upload effect, work environment improvement effect of lineman and so on. This paper studied economical effect and break-even Point for investment expense by using data that acquire in KEPCO's distribution network.

• Communications for Statistical Applications and Methods
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• 제13권2호
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• pp.219-231
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• 2006

When the correlation of two random variables is weak, the value of one variable can not be used effectively to predict the other. Even when most of the values are overlapped, it is difficult to find a linear relationship. In this paper, we propose two graphical methods of representing the measures of correlation and independence between two random variables. The first method is used to represent their degree of correlation, and the other is used to represent their independence. Both of these methods are based on the cumulative distribution functions defined in this work.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.37-54
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• 2016

The methods for estimating the change of free energy in dissipative particle dynamics (DPD) are discussed on the basis of fluctuation theorems. Fluctuation theorems are tactics to evaluate free energy changes from non-equilibrium work distributions and have several forms, as proposed by Jarzynski, Crooks, and Bennett. The validity of these methods however, has been shown merely with the molecular dynamics or Langevin dynamics. In this study, the appropriate forms of fluctuation theorems for dissipative particle dynamics, which has similar structure to that of Langevin dynamics, are suggested using Liouville's theorem, and they are proved equivalent to original fluctuation theorems. Work distribution functions, which are probability distribution functions of works exerted on the system within the systematic change, are the basics of fluctuation theorems and their shapes are turned out to be dependent on the phase space trajectory of the change of the system. The reliability of Jarzynski and Crooks methods is highly dependent on the number of simulations to measure works and the shapes of the work distribution functions. Bennett method, however, can evaluate free energy changes even when Jarzynski and Crooks methods fail to do so.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.320-323
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• 2006

A numerical study is made of a manifold and bipolar plate in polymer electrolyte fuel cells, the aim of the present study is to describe the characteristics of flow pattern In manifold and bipolar plate. The present work shows that the flow pattern in the bipolar plate is affected by the penetration flow through GDL characterized by clamping pressure and GDL intrusion in to a channel area. Manifold geometry also affects the flow distribution. The recirculation flow by bent duct destroy even distribution In manifold, the present work shows that corner rounding can improve the manifold performance.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.641-649
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• 2017

Multivariate confidence regions were defined using a chi-square distribution function under a normal assumption and were represented with ellipse and ellipsoid types of bivariate and trivariate normal distribution functions. In this work, an alternative confidence region using the multivariate quantile vectors is proposed to define the normal distribution as well as any other distributions. These lower and upper bounds could be obtained using quantile vectors, and then the appropriate region between two bounds is referred to as the quantile confidence region. It notes that the upper and lower bounds of the bivariate and trivariate quantile confidence regions are represented as a curve and surface shapes, respectively. The quantile confidence region is obtained for various types of distribution functions that are both symmetric and asymmetric distribution functions. Then, its coverage rate is also calculated and compared. Therefore, we conclude that the quantile confidence region will be useful for the analysis of multivariate data, since it is found to have better coverage rates, even for asymmetric distributions.