• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.92-99
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• 2013

Many automotive components for power generation such as motors and alternators have been widely using ferrite magnets. To ensure a high level of efficiency could be achieved in an alternator, the assembled magnets must be in good enough durability. Recently, some hairline cracks have been found on the magnet produced by manufacturers in Korea. Thus, there is an increasing concern that some of the magnets produced could cause further problems after being assembled in the alternator. Based on the standard alternator test (RS0008 : 2006), this paper has developed an accelerated failure-free test for magnets in alternator to demonstrate that assembled magnets will meet durability objective specified by the manufacturer. This guarantees the target life of the magnet with 90 percent reliability and 90 percent confidence level (R90C90). Temperature and rotation speed were selected as accelerated stress factors.

• The Korean Journal of Applied Statistics
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• v.3 no.1
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• pp.11-25
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• 1990

The objective of this paper is to propose a nonparametric distribution-free test for ordered alternatives in k crossed factor designs by using the concepts of combined factor and within-blocks ranks. We investigate the asymptotic normality of the proposed test statistic and the Pitman efficiencies. We also compared the small empirical powers of the tests considered in this paper by Monte Carlo study. Thus we can conclude that the proposed test is efficient and robust for the underlying distribution.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.1064-1081
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• 2014

This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.

• Journal of Distribution Science
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• v.11 no.2
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• pp.57-70
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• 2013

Purpose - The objective of this paper is to explain the successful methods for the revitalization of distribution and logistics of the least developed FEZs (Saemangum, Yellow-sea, and Deagu-Kyengbuk) in Korea. With the recent changes in the economic terrain of Northeast Asia as with the rise of China, Korea has developed a logistics hub concept for improving the efficiency of logistics and distribution industry and its distribution and logistics policy has received positive worldwide evaluation. Therefore, we face severe competition and must always look for ways to address these problems. Research design, Data, Methodology - This study adopts two methods to propose successful revitalization of distribution and logistics in the least developed FEZ. The first method investigates the limitation of these FEZs by analyzing the statutes, and the second one follows comparable cases. Thus, we first reviewed the efficient strategic political alternatives for the least developed FEZ, Yellow-sea, Seamangum-Gunsan, and Deagu-Kyeongbuk, through the relative institution system, law, and future plans. Next, we studied the Bin-hai Economic Free Section (Zone) in China as a comparable example. In order to analyze the competitiveness of logistics in the three FEZs (Yellow-sea, Seamangum-Gunsan, and Deagu-Kyeongbuk), the total factor productivity growth of regional manufacturing industries is divided into three sources: the external trade effect, scale effect, and technical change effect. However, this paper does not test for a positive contribution of external trade, which is a reason of non-building on these FEZs. A FEZ that shows a larger external trade effect than the others will have a comparative advantage in the logistics infrastructure and policy support. This study presented the newly applied Bin-hai FEZ in China, in order to make the studied FEZ as successful by applying the strategy of its distribution and logistics center. Results - In Korea, there is an increased focus on the benefit of the regional development of regions such as the Free Economic Zones (FEZ). We have six FEZs, Inchon, Busan-Jinhae, Guangyang, Yellow-sea, Seamangum-Gunsan, and Deagu-Kyeongbuk. However, our FEZs do not have various supporting factors needed for the logistics and distribution industry. Korea designated the above six places as FEZ and has operated to enhance national competitiveness and ensure a balanced regional development since 2003. However, most FEZs did not receive favorable feedback in the first business performance evaluation and it is necessary to take action for substantial improvements. Conclusions - Especially, over the past 10 years, even though the FEZ policy has been implemented in an effort to promote success in distribution and logistics, there are still many underdeveloped industries in logistics. The main problem is the absence of revitalization of the high value added performance in the distribution and logistics industry. However, there is a limitation to this study. We have used non-empirical method based on a case study to arrive at our findings. Future studies should use appropriate statistical methods to supplement our results and provide a solution to this problem.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.52-59
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• 2014

In general, sulfur containing odorants are added to fuel gases, such as LPG, and city gas, to prevent gas poisoning, ignition, explosion, or other accident caused by fuel gases, and to enable immediate and easy detection of fuel-gas leakage by emitting an offensive smell. In this study, sulfur free odorant for low sulfur fuel and prevention of metal corrosion were developed to replace current sulfur containing odorant for gas fuel. They were selected from 12 odorant containing non-sulfur organic compounds and evaluated by odor olfactory method (odor quality, odor intensity). Finally, selected mixture odorants were methyl isovalerate, methyl acrylate, 2-ethyl-3-methyl pyrazine with blending ratio of 50% : 40% : 10%. Final Sulfur free odorant was added 40 wt ppm in LPG fuels and evaluated fuel quality characteristics, metal corrosion test and long term stability of LPG fuel. It were limit in current LPG fuel standard in fuel quality characteristics. Final Sulfur free odorant also had no influence on metal corrosion and long term stability test with 60 days by adding in LPG fuels. Finally, they were shown to be warning agent candidates to reduce sulfur content and metal corrosion for LPG fuel.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.32-42
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• 1990

The method using Rankine Soure distribution over the hull surface and undisturbed free surface was applied to calculate the free surface flow around a ship. The ship hull as well as a local portion of the undisturbed free surface arc geometrically represented by quadrilateral panels and the source density is determined so as to satisfy the linearized free surface condition based on the double model flow. The pressure distribution, wave resistance, wave profile and hydrodynamic sinkage force and trim moment for the Wigley hull and the Series 60 hull with $C_B=0.60$ were calculated in the fixed condition. The calculated results were compared with the measured values. The dependance of the solution on the panel arrangement, particularly on the free suraface, was also studied through 11 numerical test cases for the Wigley hull.

• Communications for Statistical Applications and Methods
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• v.16 no.4
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• pp.707-711
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• 2009

We propose new cointegration tests using signs of the regressors as instrumental variable. Our tests have the asymptotic standard normal distribution and are free from the dimension of regressors under the null hypothesis of no cointegration. A Monte-Carlo simulation shows that the proposed tests have a stable size and an improved power. Particulary, the tests have better power for small numbers of observations.

• Journal of the Korean Ceramic Society
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• v.15 no.4
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• pp.193-198
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• 1978

Test-bricks were prepared from an artifically graded Ham Kang sand and a commercial CaO and autoclaved for 6 hours at $16 kg/cm^2$ pressure $(203^{\circ}C)$. Bricks were tested for compressive strength, free lime, saluble silica and amount of water absorption. Physical properties of bricks were very much depended on the size distribution of sand particle and the amount of soluble silica in bricks.

• Journal of Distribution Science
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• v.19 no.7
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• pp.19-27
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• 2021

Purpose: Former research has argued that organizations in distribution channels face several issues to make a better team-based system. The purpose of the present research is to measure between employee's job performance and three major issues which disturb a solid team system. Research design, data and methodology: Scant past studies are available to guide for team practitioners which elements should be eliminated to improve team performance. To achieve this goal, the present authors obtained 267 US workers in distribution channels and conducted ANOVA test to measure the relationship between three team issues (Free-rider, Trust, and Communication) and job performance. Results: Our statistical findings clearly suggests that there was a statistically recognizable difference at the significance level of probability between the mean value of employees' job performance and three major issues, showing the high degree of job performance can be occurred by eliminating three major team issues. Conclusions: Therefore, the present research concludes that it is necessary that team-based management in the supply chain should focus on removing free-rider issues and also adopt open communication lines to overcome team-building challenges due to communication. Above all else, the ability to increase trust can be enhanced via task delegation and more team members' engagement.

• Journal of Distribution Science
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• v.18 no.8
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• pp.113-125
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• 2020

Purpose: The purpose of this paper is to investigate the effect of interaction between product category (fresh vs. indulgent product) and shopping options (shipping charge and delivery time) on customer satisfaction and purchase intent in an e-commerce context. When ordering groceries online, consumers begin to allocate a larger share of their grocery budget toward product categories that generally contain healthier items at the expense of product categories that generally contain more indulgent products. Moreover, customers are extremely sensitive to shipping options such as shipping charges and delivery time. Therefore, this research investigates the issue at a more segmented level to focus on the impact that one dimension of logistics service quality - product category, shipping charge, and delivery time have on customer satisfaction and purchase intent. Research design, data, and methodology: To test the theoretically derived priori hypotheses concerning product category, shipping charges, delivery time, satisfaction, and purchase intent, this research presented a scenario-based experiment. Eight treatment groups were assigned by the method of product category (fresh produce vs. indulgent product), shipping charge (free vs. paid), and delivery time (one-day vs. two to three days). A total of 240 subjects were divided into groups and exposed to one of the eight scenarios. Participant's purchase intention was the dependent variable, and ANOVA and L-matrix were used to analyze for main and interactive effects between factors. Conclusions: Results indicated that in tests 1 and 2, free shipping and fast delivery time increased consumer satisfaction as well as purchase intent, and fast delivery moderated the impact of free shipping on consumer satisfaction and purchase intent. Test 3 showed that the effect of free shipping on consumer satisfaction and purchase intent moderated by fast delivery for indulgent products. In contrast, fast delivery for fresh products moderated the effect of paid shipping on consumer satisfaction and purchase intent. Consistent with this proposed mechanism, the relative importance of fresh produce versus indulgent products highlights the effect of shipping options on consumer satisfaction and purchase intent when ordering the target product in an e-commerce context. We conclude with a discussion of the theoretical and practical implications of our findings.