• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.75-75
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• 1996

The rapid expansion for the auto-industry and the worldwide trend toward non-asbestos friction materials for brake lining force our industry to transfer into non-asbestos ones from asbestos-based friction materials. Furthermore, it is imperative for the friction materials to have technological excellence and lower production cost to be competitive in the world market. There is no known theoretical procedures to formulate friction materials. It, rather, depends on the trial and error process. Thus, it is quite clear how important it is to accumulate the know-how on the formulation and manufacturing the friction material. This study concerns the practical ways of conceptualizing the formulation and optimizing the manufacturing process. This study focused on the development of formulation for non-asbestos friction material as well as deriving the physical properties of the trial product to prove its validity and applicability. Elaboration of the formula and optimizing scheme of the manufacturing process to get better quality are also sought. Physical properties were obtained by constant velocity test dynamotest, hardness test and strength test. Differential scanning calorimeter was also used to analyze the thermal reactions of organic constituents, microstructures, bond effects, and degree of mixture.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.7-14
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• 1996

The rapid expansion for the auto-industry and the worldwide trend toward non-asbestos friction materials for brake lining force our industry to transfer into non-asbestos ones from asbestos-based friction materials. Furthermore, it is imperative for the friction materials to have technological excellence and lower production cost to be competitive in the world market. There is no known theoretical procedures to formulate friction materials. It, rather, depends on the trial and error process. Thus, it is quite clear how important it is to accumulate the know-how on the formulation and manufacturing the friction material. This study concerns the practical ways of conceptualizing the formulation and optimizing the manufacturing process. This study focused on the development of formulation for non-asbestos friction material as well as deriving the physical properties of the trial product to prove its validity and applicability. Elaboration of the formula and optimizing scheme of the manufacturing process to get better quality are also sought. Physical properties were obtained by constant velocity test dynamotest, hardness test and strength test. Differential scanning calorimeter was also used to analyze the thermal reactions of organic constituents, microstructures, bond effects, and degree of mixture.

• 대한기계학회논문집B
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• 제26권7호
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• pp.919-926
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• 2002

Down scaled combustor undergoes increased heat loss that results in incomplete combustion or quenching of the flame as a consequence. Therefore, effect of enhanced heat loss should be understood to design a MEMS scale combustion devices. Existing combustion models are inadequate for micro combustors because they were developed for analysis of regular scale combustor where heat loss can be ignored during the flame propagation. In this research a combustion model is proposed in order to estimate the heat loss and predict quenching limit of flame in a down scaled combustor. Heat loss in the burned region is expressed in a convective form as a product of wall surface area, heat transfer coefficient and temperature difference. Comparison to the measurements showed satisfactory agreement of the pressure and temperature drop. Quenching is accounted for by introducing a correlation of quenching parameter and heat loss. The present model predicted burnt fraction of gases with reasonable accuracy and proved to be applicable in thermal design of a micro combustor.

• 대한기계학회논문집A
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• 제25권2호
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• pp.330-337
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• 2001

Wire drawing process of the high carbon steel with a high speed is usually conducted at room temperature using a number of passes or reductions through consequently located dies. In multi-stage drawing process, temperature rise in each pass affects the mechanical properties of final product such as bend, twist and tensile strength. Also, this temperature rise during the deformation is the reason that the wire in drawing process is broken by the embrittlement due to rapid strain aging effect. This paper presents the estimation of the wire temperature for the multi-stage wire drawing process. Using the proposed calculation method of wire temperature, temperature rise at deformation zone as well as temperature drop in block considering the heat transfer between the block and wire were calculated. As these calculated wire temperatures were applied to the real industrial fields, it was known that the calculated results were in a good agreement with the measured wire temperature.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.1-9
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• 2001

The recent spread of scaled telemanipulation into microsurgery and the nano-world increasingly requires the identification of the possible operation region as a main system specification. A teleoperation system is a complex cascaded system since the human operator, master, slave, and communication are involved bilaterally. Hence, a small time delay inside a master and slave system can be critical to the overall system stability even without communication time delay. In this paper we derive an upper bound of the scaling product of position and force by using Llewellyns unconditional stability. This bound can be used for checking the validity of the designed bilateral controller. Time delay from the sample and hold of computer control and its effects on stability of scaled teleoperation are modeled and simulated based on the transfer function of the teleoperation system. The feasible operation region in terms of position and force scaling decreases sharply as the sampling rate decreases and time delays inside the master and slave increase.

• Journal of Power Electronics
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• 제18권3호
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• pp.778-788
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• 2018

Magnetic resonance wireless power transfer (WPT) in the marine environment can be utilized in many applications. However, energy loss in seawater through eddy loss (EL) is another consideration other than WPT in air. Therefore, the effect of system parameters on electric field intensity (EFI) needs to be measured and ELs calculated to optimize such a system. In this paper, the usually complicated analytical expression of EFI is simplified to the product of frequency, current, coil turns, and a coefficient to analyze the eddy current loss (ECL). Moreover, as the calculation of ECL through volume integral is time-consuming, the equivalent eddy loss impedance (EELI) is proposed to help designers determine the optimum parameters quickly. Then, a power distribution model in seawater is conceived based on the introduction of EELI. An optimization flow chart is also proposed according to this power distribution model, from which a prototype system is developed which can deliver 100 W at 90% efficiency with a gap of 30 mm and a frequency of 107.1 kHz.

• 한국의상디자인학회지
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• 제12권4호
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• pp.103-114
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• 2010

This study aims to examine current status of cultural products in Mokpo city and their problems and develop cultural products design suitable to this situation. Cultural products in Mokpo sold here are made from China and have lower quality or traditional crafts and folkcrafts which can be purchased anywhere in Korea and they are not enough to show identity or image of Mokpo city. So I mixed the logos of 'mokpo city' and 'national maritime museum' based on main motive of 'modern Korean ship and shipbuilding tools' held by 'National Maritime Museum' and 'Goebukseon (turtle ship)' and 'Hanseon' which are suitable to the image of maritime culture as cultural products advocated by Mokpo city and developed one design style for print. This design is applied to T-shirts, necktie, cap, cushion and mug. Silk print, transfer print and needlework techniques are applied to each item and the whole cultural products have design of set concept. It is a case of applying modern product marketing technique to our cultural products not a design for only one item, is aimed to recreate spiritual and cultural value that a region has as daily goods to be used by general consumers and show the chance and possibility to complement shortcomings of existing cultural products and develop traditional culture having locality.

• 기술혁신연구
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• 제8권2호
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• pp.97-117
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• 2000

TOEM strategy is widely used in Japan and Korea because of the diverse advantages such as cost sharing, technology transfer, equipment lease and base technology acquisition between parent company and OEM supplier. There are, however, some disadvantages that (1)OEM suppliers are likely to be reactive to environmental changes and (2) may have difficulty in building competitive position and long-term growth. When the parent company relocates its plant to foreign countries to achieve lower labor cost or to enhance value added this change will affect directly the OEM supplier's outcome. The parent company's divestiture from existing businesses will also affect the OEM supplier. For the OEM supplier to survive in face of these strategic changes it must enter the new countries with the parent company. Alternatively, the OEM supplier must actively diversify its technologies based on its core capabilities of existing product and process technologies and seek new business arenas. The strategy of aligning its businesses with the parent company's new business strategy allows the OEM supplier to share the new market while it requires the OEM supplier to develop core capabilities. In Korea many small and medium sized OEM suppliers are dependent on a few large companies. For the industry structure in Korea where industry concentration is extremely high OEM suppliers should move away from the past strategy, where they are dependent on the parent company's low profitability businesses. They should actively enter new businesses for which parent companies enter to achieve long-term growth.

• 한국항공운항학회지
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• 제19권3호
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• pp.69-82
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• 2011

This paper tried to find out what the main factors are to impact on satisfaction level of transit passengers at Incheon airport. Incheon airport has made lots of transit facilities and services to attract transit passengers from neighboring airports to increase transit rate as high as advanced foreign airports such as Heathrow, Schiphol and Hong Kong. A survey was performed on 450 transit passengers resting at airport transit lounge in airside area. According to the result, it was found out to be significant factors affecting satisfaction of transit that convenience of security screening, price of duty-free product, a direction board & signage and terminal orientation among Chinese transit passengers. On the other hands, it seemed that Japanese transit passengers thought diversity of airline routes, convenient transfer flight schedule, total transit time and terminal orientation are major variables affecting their satisfaction. Considering the effect of demographic factors, Chinese passenger's satisfaction was more affected by age, travel purpose, the number of travel per year and flight destinations. However, Japanese transit passenger's satisfaction was only affected by the flight destinations, especially willing to travel to North America and Europe.

• 지역연구
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• 제11권1호
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• pp.31-60
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• 1995

The distribution of economic activity over a mutually exclusive and exhaustive categorical industry-region matrix is modeled as a composition of two random components: the probability-like share distribution of jobs and the dynamic evolution of absolute aggregates. The former describes the individual activity location choice by comparing the predicted profitability of the current industry-region pair against that of all other alternatives based on the available information on industry-specific, region specific, or activity specific attributes. The latter describes the time evolution of macro-level aggregates using a dynamic reduced from model. With the seperation of micro choice behavior and macro dynamic aggregate constraint, the usual independence and identicality assumptions become consistent with the activity share distribution, hence multi-regional industrial migration can be represented by a set of probability evolution equations in a conservative Markovian from. We call this a Micro-Macro Composition Approach since the product of the aggregate prediction and the predicted activity share distribution gives the predicted activity distribution gives the predicted activity distribution which explicitly considers the underlying individual choice behavior. The model can be applied to interesting practical problems such as the plant location choice of multinational enterprise, the government industrial ploicy to attract international firms, and the optimal tax-transfer mix to influence activity location choice. We consider the latter as an example.