• Journal of Energy Engineering
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• v.22 no.2
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• pp.237-244
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• 2013

The engine oil is used for lubrication of various internal combustion engines. Recently, the vehicle and engine oil manufacture usually guarantee for oil change over 15000~20000 km mileage, but the most of driver usually change engine oil every 5000 km driving in korea. It can cause to raise environmental contamination by used engine oil and increase the cost of driving by frequently oil change. In this study, we investigate the various physical properties such as flash point, pour point, kinematic viscosity, cold cranking simulator characteristics, total acid number, four-ball test and concentration of metal component for fresh engine oil and used engine oil after real vehicle driving (5000 km, 10000 km). The result showed that the total acid number, wear scar diameter by four-ball test, Fe and Cu had increased than fresh engine oil, but 2 kind of used oil (5000 km and 10000km) had similar physical values and concentration of metal component.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.697-704
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• 2017

This study was carried out to investigate and alleviate the vibration problem of commercial high-speed trains. First, the measurement of the carbody vibration was performed, in order to determine the vibration level of the high-speed train. The measurement result showed that the vibration level of the driver cab was higher than that of the passenger car and that the vibration became bigger toward the trailing end of the train. The vertical vibration of the driver cab and passenger car was larger than the transverse vibration, and the maximum value of the vibration in the ballast section was larger than that in the concrete section. A dynamic analysis was carried out to improve the vibration of the KTX-Sancheon train. The results of the analysis showed that it is necessary to reduce the vibration of the driver cab and both ends of the passenger cars. To reduce the vibration of the driver cab, it was recommended that the stiffness of the secondary coil spring be reduced and the damping coefficient of the secondary vertical damper be increased. It was found that the failure of the suspension system could be the origin of the vibration problem of the high-speed train. The proper management of wheel wear plays an important role in the improvement of the operation efficiency and reduction of the carbody vibration of high-speed trains, and research is underway to change the present wheel profile to increase the mileage between wheel turning.

• Journal of Distribution Research
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• v.12 no.2
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• pp.79-102
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• 2007

Consumers evaluate stores by comparing stores that we, in their minds, similar and are competitive with one another; and in this way, the term "consideration set of stores" is defined as those store alternatives the consumer is aware of and evaluates positively. The purpose of this study is to aid in understanding the consideration set of stores in store choice processes in apparel product purchases. More specifically, this study aims to clarify the relation between consideration set of stores and importance of store image. As a result, the respondents of quantitative study were classified into seven groups by the number of stores and store types they considered: 1) "small-road shop sets group" ; 2) "small-market sets group" ; 3) "small- department store sets group" ; 4) "small-department store/outlet sets group" ; 5) "large-department store/market sets group" ; 6) "large-department store/road shop sets group" ; and 7) "large-department store sets group". Further, significant differences among the groups in the importance of store image were observed. For example, low prices were an important factor in both the small-market considering group and large-department store/market considering group when choosing a retail store, there were also differences in the considering groups in that for the small-department store considering group, store mileage-discount cards were important whereas ample space for relaxation around the stores were important retail store selection factors for the large-department store/road shop considering group. This study may provide a useful direction to retailers in finding out who the target customers and competitive stores are and allow retailers to make proper marketing strategies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.481-491
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• 2016

This study analyzed the customer's revisit concepts and storytelling by restaurant customers to identify the elements that can attract the attention of customers. The restaurant concept or advertising, restaurant decor will also have to change to emphasize the comparative advantage of the features in the menu of a restaurant or other restaurants / service that tells a story. Membership cards or money, or the same convenience and use of the restaurant non-monetary 'transition cost' can compensate for the negative emotions and low satisfaction level of restaurant customers and help them choose to revisit the restaurant. Therefore, if such a transition takes full account of the effects of the cost to the customer, it can be used as an effective means. In class restaurants, such as the food and customer service, the increased levels of the restaurant atmosphere and empirical elements, such as store concept and physical environment, can improve the positive consumer sentiment, strengthen the customer satisfaction and have a positive effect on the customers' revisit intention. It is also important to improve the level of visual texture using light. In addition, positive consumer sentiment can be induced using the store concept, the physical environment, and experiential elements. In other words, membership cards, mileage points, and various financial and non-financial inducements as a marketing tool will have a positive impact on the customer's revisit intention.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.1
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• pp.57-68
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• 2010

Increase in greenhouse gas emissions during the last century has led to remarkable changes in our environment and climate system. Many policy measures have been developed to reduce greenhouse gas emissions across the world, many of which require our lifestyle changes from energy-intensive to energy-saving. One of the changes in our living patterns is to consider food miles. A food mile is the distance food travels from where it is produced to where it is consumed. Providing information of food miles will help people choose low mileage food, helping promote a "green consumption" action and lead to a low carbon society with emission reduction systems. In this study, 10 items are selected from 23 Harmonized commodity description and 2-digit coding system (HS) to estimate their food miles, and $CO_2$ emissions released in the transportation of imported food. For the estimation, four countries are chosen-Korea, Japan, United Kingdom (UK) and France, with Korea and Japan's 2001, 2003, and 2007 trade statistics and UK and France's 2003 and 2007 trade statistics used. As a result, Korea showed in 2007 the highest level of food miles and $CO_2$ emissions per capita among 4 countries. That suggests that Korea should make an effort to purchase local food to reduce food miles and use low-carbon vehicles for food transport, contributing to reducing greenhouse gas emissions.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.274-278
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• 2013

Automatic transmission fluid (ATF) is used as an automatic transmission in the vehicle or as a characterized fluid for automatic transmission. Recently, vehicle manufacturers usually guarantee for changing fluids over 80000~100000 km mileage or no exchange. However, most drivers usually change ATF below every 50000 km driving distance when driving in Republic of Korea according to a survey from the Korea Institute of Petroleum Management which can cause both a serious environmental contamination by the used ATF and an increase in the cost of driving. In this study, various physical properties such as flash point, pour point, kinematic viscosity, dynamic viscosity at low temperature, total acid number and four-ball test were investigated for both fresh ATF and used ATF after the actual vehicle driving distance of 50000 km and 100000 km. It was shown that most physical properties were suitable for the specification of ATF, but the foam characteristics of the used oil after running 100000 km was unsuitable for the specification of fresh ATF. Therefore, the exchange cycle of ATF every 80000~100000 km driving distance is recommended considering great positive contributions to preventing environmental pollution and reducing driving cost.

• Journal of Distribution Science
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• v.12 no.12
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• pp.101-106
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• 2014

Purpose - This study reviews the achievements of a pilot project for the revitalization of a commercial district performed for three years after its establishment in 2011. The project for the revitalization of the commercial district was performed to create a new local community space in connection with the traditional market and nearby districts. Although it was a pilot project, the project for the revitalization of the commercial district has been performed for almost three years. Therefore, this seems a proper time to conduct an interim evaluation of the project. This study aims to review and evaluate how the government support policy is influential for the revitalization of the commercial district. In other words, this research aims to identify what projects positively affected consumers' intention to revisit the downtown commercial area among the commercial district revitalization projects-promotion events, promotion activities, education, merchants cooperation system, IT projects, cultural events, and residents' communication. Research design, data, and methodology - This study designated seven management improvement projects affecting commercial district revitalization based on preceding studies. The survey of the degree of satisfaction on seven management improvement projects was executed targeting consumers who visited the commercial areas. Additionally, visitors' revisit intentions regarding currently visited commercial areas were also investigated. Therefore, revisit intention was set as a dependent variable and the satisfaction degrees of the respective management improvement projects were set as the independent variables. A total of 1,209 consumers were examined in six districts in the country. Result - Multiple regression analysis results showed that cultural events, education, the merchants' cooperation system, and IT projects brought statistically significant effects to the revisit intentions of consumers. In contrast, promotion events, resident communication projects, and promotion activities did not affect the revisit intentions of consumers. Particularly, the residents' communication project did not show significant influence because of consumers' recognition that it is similar to a cultural event. Conclusion - The following implications for the revitalization of business districts in the urban central area are drawn. From a general perspective, the businesses of culture, education, and cooperative system among seven businesses play positive roles regarding the intention to revisit so that the project is required to be promoted periodically through unique performances differentiated for each district, the merchant training reinforced for professionalism, and the expansion of joint events of merchants. Moreover, the sales promotion project and public relations activity are shown to be not influential to the intention to revisit. Therefore, while short-term sales promotion such as one-time gift events are required, sales promotion and public relation activities to induce revisits by mileage savings and accumulated gift presentation to attract long-term customers are required. The IT business is positively influential to the intention of revisit. Therefore, detailed information on the revitalized commercial district should be provided and additional functions such as discount coupons for continuous utilization should be included in the mobile app and the website.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.629-634
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• 2017

In the case of the UHP (Ultra high performance) tire that the demand has increased rapidly, compared with the commonly used tire, severe deformation has been observed because of the low aspect ratio. When repeated deformations are applied to the sidewall rubber, accumulated fatigue damage may cause fatigue failure. Thus, the evaluation of the durability of the tire sidewall rubber has become a very important issue to prevent accidents that occur while the vehicle is running. However, the research and design criteria for the durability performance of the tire sidewall rubber hardly exist. In this study, we suggest a lifetime prediction formula using strain energy density obtained by performing tensile tests and fatigue tests on two different kinds of the tire sidewall compounds. Additionally, the applicability of our findings for low fuel consumption tires was reviewed by converting the fatigue life of the sidewall rubber into the expected mileage of the tire.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.72-72
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• 2012

Lithium rechargeable batteries have been widely used as key power sources for portable devices for the last couple of decades. Their high energy density and power have allowed the proliferation of ever more complex portable devices such as cellular phones, laptops and PDA's. For larger scale applications, such as batteries in plug-in hybrid electric vehicles (PHEV) or power tools, higher standards of the battery, especially in term of the rate (power) capability and energy density, are required. In PHEV, the materials in the rechargeable battery must be able to charge and discharge (power capability) with sufficient speed to take advantage of regenerative braking and give the desirable power to accelerate the car. The driving mileage of the electric car is simply a function of the energy density of the batteries. Since the successful launch of recent Ni-MH (Nickel Metal Hydride)-based HEVs (Hybrid Electric Vehicles) in the market, there has been intense demand for the high power-capable Li battery with higher energy density and reduced cost to make HEV vehicles more efficient and reduce emissions. However, current Li rechargeable battery technology has to improve significantly to meet the requirements for HEV applications not to mention PHEV. In an effort to design and develop an advanced electrode material with high power and energy for Li rechargeable batteries, we approached to this in two different length scales - Atomic and Nano engineering of materials. In the atomic design of electrode materials, we have combined theoretical investigation using ab initio calculations with experimental realization. Based on fundamental understanding on Li diffusion, polaronic conduction, operating potential, electronic structure and atomic bonding nature of electrode materials by theoretical calculations, we could identify and define the problems of existing electrode materials, suggest possible strategy and experimentally improve the electrochemical property. This approach often leads to a design of completely new compounds with new crystal structures. In this seminar, I will talk about two examples of electrode material study under this approach; $LiNi_{0.5}Mn_{0.5}O_2$ based layered materials and olivine based multi-component systems. In the other scale of approach; nano engineering; the morphology of electrode materials are controlled in nano scales to explore new electrochemical properties arising from the limited length scales and nano scale electrode architecture. Power, energy and cycle stability are demonstrated to be sensitively affected by electrode architecture in nano scales. This part of story will be only given summarized in the talk.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.28-34
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• 2014

Automatic transmission fluid (ATF) is used for automatic transmissions in the vehicle as the characterized fluid. Recently, the vehicle manufacture usually guarantee for fluid change over 80000~100000 km mileage or no exchange, but most drivers usually change ATF below every 50000 km driving in Republic of Korea. It can cause to raise environmental contamination by used ATF and increase the cost of driving by frequently ATF change. In this study, we investigate the various physical properties such as flash point, fire point, pour point, kinematic viscosity, cold cranking simulator, total acid number, and metal component concentration for fresh and used ATF after driving (50000 km, 100000 km). The result showed that the total acid number, pour point, Fe, Al and Cu component had increased than fresh ATF, but 2 kind of used oil (50000 km and 100000km) had similar physical values and metal component concentration.