• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.27-62
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• 1996

As an exploratory attempt, this study examines the patterns of global R&D activities of industrial firms, focusing on the management of overseas R&D centers in terms of their location, primary missions, management style, organizational structure and communication and global human resource management system Based on a review of existing studies mainly undertaken in advanced countries and cases of foreign MNCs, several hypothetical relationships are postulated : 1) There appears a strong relationship between the purpose and location of R&D activities : 2) Different levels of global management and technological capability lead to different types of overseas R&D organizations : 3) The relationship between autonomy of overseas R&D organizations and their R&D performance will be moderated by organization size, development time pressure, and a need for internal efficiency : 4) Frequent communication between the headquarter and overseas R&D organizations will increase R&D performance 5) Mutual exchange of R&D professionals between the headquarter and overseas R&D organizations will be positively related with R&B performance. In addiction, this study explores the current state of global R&D activities of selective firms in Korea, based on ie-depth interviews, and analyzes the sources of problems in their global R&D management. Finally, theoretical and managerial implications of this study are discussed and future research directions are proposed.

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.16-20
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• 2017

Current maintenance system are unable to suggest solid basis of maintenance for roating and static equipment. When a filure occurs, replacement or repair without proper process of failure cause analysis would often result in even greater risk. Therefore in this study, a procedure of Reliability Centred Maintenance is develped in order to perform maintenance in preventive mainer (PM), and to effectively manage risk of any equipment based on failure types and respective rates of failure. Ultimately an equipment with higher risk will be monitored which will lead to effectively prevent and manage any major accident.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.865-873
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• 2017

Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.4.1-4.1
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• 2009

The dream of futurists andtechnologists is to build complex, multifunctional machines so small that theycan only be seen with the aid of a microscope. The unprecedented technologyadvancements in miniaturizing integrated circuits on semiconductors, and theresulting plethora of sophisticated, low cost electronic devices demonstratethe impact that micro/nano scale engineering can have when applied only to thearea of electrical and computer engineering. Emerging research efforts indeveloping organic and inorganic nano materials together with using micro/nanofabrication techniques for implementing integrated multifunctional devices hopeto yield similar revolutions in other engineering fields. By cross linking theindividual engineering fields through micro/nano technology, various organicand inorganic materials and miniaturized system devices can be developed thatwill have future impacts in the IT and life science applications. Yet to buildthe complex micromachines and nanomachine of the future, engineering will needto develop the technology capable of seamlessly integrating these materials andsubsystems together at the micro and nano scales. The micromachines of thefuture will be “integrated nanosystems,” complex devices requiring the integration of multiple materials,phenomena, technologies, and functions at the same platform. To develop thistechnology will require great efforts in materials science and engineering, infundamental and applied sciences. In this talk, we will first discuss thenature of micro and nanotechnology research for IT and life sciences, and thenintroduce selected current activities in micro and nanotechnology research fororganic and inorganic materials and devices. The newly developed micro/nanofabrication processes and devices, combined with in-depth scientificunderstandings of materials, can lead to rapid development of next generationsystems for applications in IT and life sciences.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.159-166
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• 2010

The speed at which products are developed and released to market is tightly linked to profitability and market share. Hence, many companies are still in a desperate need of real Rapid Tooling (RT) technologies which can really help to expedite their prototype tooling and pre -production tooling for injection molding. Many other companies that have been very skeptical of RT technologies developed so far are working on Hybrid Tooling (HT) that can really meet the market standards. With the conviction that HT can be a reliable alternative for current RT technologies, this paper describes the experimentation how HT process has been being successfully established and effectively applied with typical case studies. Through the experimentation, Ceramic-filled SLA tooling was found to be aptly suited for the low grade mold, and Metal SLS tooling was found to be aptly suited for the medium volume mold both in terms of the lead time, dimensional accuracy, and tooling cost.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.327_328
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• 2009

The insulator being used for transmission line is to mount the charged conductor on the tower or other supports. The insulators are classified according to its material: porcelain, glass and polymer. Polymer insulators are also called as composite insulator or non ceramic insulator (NCI). Insulators are a major element of a power transmission system. Since a faulty insulator can lead to a wide spreading blackout, it must have sufficient mechanical and electrical strength. It must be durable, have high electrical insulation and be able to withstand a leakage current. It must also be able to withstand the toughest weather conditions. In Korea, porcelain insulators have been used widely. However, to make compact equipment and keep up with global trends, we have enhanced domestic production of polymer insulator and are encouraging its applications. Accordingly, this thesis will look at types of insulators, use and trends, and prospects of insulators application in the field.

• Korean Journal of Cognitive Science
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• v.29 no.2
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• pp.85-104
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• 2018

Peer assessment in educational setting, refers to activities in which students provide grades or comments on other students' accomplishments such as writing, presentation, or performances. In case of writing, peer assessment can allow instructors to give out more writing assignments, which were often avoided because of the burden of grading. Moreover, grading other students' writing can enhance learning by having students participate in the assessment process. This review will introduce major peer assessment systems and results from empirical studies on peer assessment, examine obstacles to its more wide-spread use, and discuss topics for further research. We hope this paper will facilitate further studies and use of peer assessment in actual educational settings, and eventually lead to many changes in assessment and teaching in Korea.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.12
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• pp.755-760
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• 1999

Various fluoride films were investigated for a gate insulator of thin film transistor application. Conventional oxide containing materials like $SiO_2\;Ta_2O_5\; and \; Al_2O_3$ exhibited high interface states which lead to an increased threshold voltage and poor stability of TFT. In this paper, we investigated gate insulators using a binary matrix system of fluoride such as $CaF_2,\; SrF_2\; MgF_2,\; and\; BaF_2$. These materials exhibited an improvement in lattice mismatch, interface state and electrical stability. MIM and MIS devices were employed for an electrical characterization and structural property examination. Among the various fluoride materials, $CaF_2$ film showed an excellent lattice mismatch of 5%, breakdown electric field higher than 1.2MV/cm and leakage current density of $10^{-7}A/cm^2$. MIS diode having $Ca_2$ film as an insulation layer exhibited the interface states as low as $1.58\times10^{11}cm^{-2}eV^{-1}$. This paper probes a possibility of new gate insulator materials for TFT applications.

• Molecules and Cells
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• v.37 no.7
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• pp.503-510
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• 2014

Lymphatic vessels provide essential roles in maintaining fluid homeostasis and lipid absorption. Dysfunctions of the lymphatic vessels lead to debilitating pathological conditions, collectively known as lymphedema. In addition, lymphatic vessels are a critical moderator for the onset and progression of diverse human diseases including metastatic cancer and obesity. Despite their clinical importance, there is no currently effective pharmacological therapy to regulate functions of lymphatic vessels. Recent efforts to manipulate the Vascular Endothelial Growth Factor-C (VEGFC) pathway, which is arguably the most important signaling pathway regulating lymphatic endothelial cells, to alleviate lymphedema yielded largely mixed results, necessitating identification of new targetable signaling pathways for therapeutic intervention for lymphedema. Zebrafish, a relatively new model system to investigate lymphatic biology, appears to be an ideal model to identify novel therapeutic targets for lymphatic biology. In this review, we will provide an overview of our current understanding of the lymphatic vessels in vertebrates, and discuss zebrafish as a promising in vivo model to study lymphatic vessels.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.73-82
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• 2008

Recently MR CDC damper has been applied to semi-active suspension control system gradually. Compared to former hydraulic CDC damper, it has rapid time response performance as well as simple internal structure and wide range of damping force. In order to develop control logic algorithm which enables to take maximum advantage of unique characteristics of MR CDC damper, it is inevitable to perform a thorough investigation into its nonlinear performance. In many previous researches, MR fluid model was either simply assumed as Bingham Plastic, or a phenomenological model based on experiment was established instead to predict damping performance of MR CDC damper. These experimental flow model which is not based on flow analysis but intentionally built to fit damping characteristics, may lead to totally different results in case of different configuration or structure of MR CDC damper. In this study, a generalized flow formula from mathematical flow model of MR fluid for annular orifice is derived to analyze and predict damping characteristics when current is excited at piston valve.