• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.405-408
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• 2008

From the previous researches about flow characteristic of micro-nozzle, we found that viscosity and back pressure induced heavy losses in micro nozzle. To overcome thess losses, we began to study new conceptual micro propulsion system that is thermal transpiration based micro propulsion system. It has no moving parts and can pump the gaseous propellant by temperature gradient only (cold to hot). Most of previous research on thermal transpiration is in its early stage and mainly studied for application to small vacuum facility or gas chromatography in ambient condition using nanoporous material like aerogel. In this study, we focus on basic research of propulsion system based on thermal transpiration using polyimide material in vacuum conditions.

• International Journal of Railway
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• v.4 no.1
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• pp.5-11
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• 2011

The purpose of the present study is to develop conceptual design of a railway vehicle simulator based on a scaled model. Although the scaled simulator is limited in its ability to manipulate the full dynamics of a full-size railway vehicle, it has been known to have an advantage in that it could provide means of testing the fundamental dynamic behavior within a limited laboratory space and at low operation cost. The present study proposes a design strategy for a simulator so that a small scaled roller rig could be fabricated and operated in laboratory setting based on the design philosophy. The data obtained from experimental testing using a scale model can be used to verify and interpret the dynamic performance of full-scale railway vehicle by applying appropriate non-dimensional analysis.

• ETRI Journal
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• v.27 no.6
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• pp.666-676
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• 2005

In recent years, motivated by the emergence of ubiquitous computing technologies, a new class of networked robots, ubiquitous robots, has been introduced. The Ubiquitous Robotic Companion (URC) is our conceptual vision of ubiquitous service robots that provide users with the services they need, anytime and anywhere in ubiquitous computing environments. To realize the vision of URC, one of the essential requirements for robotic systems is to support ubiquity of services: that is, a robot service must be always available even though there are changes in the service environments. Specifically robotic systems need to be automatically interoperable with sensors and devices in current service environments, rather than statically preprogrammed for them. In this paper, the design and implementation of a semantic-based ubiquitous robotic space (SemanticURS) is presented. SemanticURS enables automated integration of networked robots into ubiquitous computing environments exploiting Semantic Web Services and AI-based planning technologies.

• Journal of Industrial Technology
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• v.18
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• pp.343-353
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• 1998

Effective design of a database is essential for operating application systems efficiently. This paper discusses database design for a geographic information system. This goals of database design are multiple: to satisfy the information content requirements of the specified users and applications; to provide a natural and easy-to-understand structuring of the information; and to support processing requirements and any performance objectives such as response time, processing time, and storage space. Database design is a very complex process and is decomposed in three phases: conceptual, logical, and physical design. In this paper, we first collect and analyze the requirements for a geographic information system. We also perform database design for these requirements through the three design phases systematically. Our results would contribute to the effective construction of a database for a geographic information system.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.467-473
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• 2005

A continuously variable transmission (CVT) with an inner spherical traction drive was conceptually designed for bicycle usage. The range of the overall speed ratio is from 1.0 to 4.5. The rated power and pedal speed are 100 Watts and 6 rad/s, respectively. The peculiar packageability, high-level power efficiency and high torque capacity were considered in the design process. A compact CVT that can be installed within a $244\times125\times160mm^3$ space and is above 0.9 in efficiency for the rated values was numerically designed. The distribution of efficiency according to the input torque and input speed were calculated. Gradeability in the prescribed operation mode was simulated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.687-693
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• 2011

In this paper, problems and solutions are proposed for applying IEC 61850 to Distribution Automation System(DAS). Communication protocol integration in power automation system have issued by IEC standards, IEC 61850 of them has researched for applying IEC 61850 to many areas of power system in spite of that it was made for substation automation system. Especially, DAS is just about to apply IEC 61850 by communication network change from serial to ethernet although DNP 3.0 is used. But it's impossible to apply directly IEC 61850 to DAS by difference of environment which unfixed wide area and separated nodes in power distribution system unlike concept of IEC 61850 is made by Substation Automation System(SAS) environment of limited space. Thus, this paper proposed applications of three types which conceptual, practical, and future to consider problems and solutions when apply IEC 61850 to Ethernet based DAS.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.73.1-73
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• 2001

To utilize the uranium resources contained in the spent nuclear fuel generated from the nuclear power plants, the remote handling and dismantling technology is required. The dismantling process of the sport fuel is the most common process involved in the spent fuel recycling, the rod consolidation and the disposal processes. Since the machine used in the dismantling process are located and operated in isolated space, so called a hot cell, the reliability of machines is very important. To enhance the reliability of the process, in this research, the graphical monitoring system is developed for the fuel dismantling process. The graphic model of each machine is composed of many parts and every parts of the graphic model are given their own kinematics. Using the kinematics and simulating the graphic model in the virtual environment, the validity of the conceptual design can be verified before ...

• Asian Journal of Innovation and Policy
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• v.10 no.2
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• pp.159-176
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• 2021

Over the past two decades, smart cities have been attracting attention as a means of solving urban problems and as a model for securing urban sustainability. Many studies have been conducted in various fields such as conceptual definitions, classification, new technologies, case analysis, and civic participation of smart cities. In particular, applicable technologies and their importance have been highlighted so far. However, since a city is a complex and meta-systematic space, it is the overly optimistic prospect that technology, one of the smart city components, will lead to successful smart cities. This study elucidates the impediments to driving smart cities as a case study of South Korea, a leading country in smart technology and digital transformation. We examined three comprehensive national plans for promoting smart cities and conducted focus group interviews with experts in smart cities to analyze the obstacles to carrying smart cities. We classified the thirteen impediments into technological, industrial, governmental, and social factors as a result. Some of them are generic issues in policy establishment and enforcement, while others are specific to smart cities.

• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.31-34
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• 2007

Superconducting synchronous motors compared with conventional motors can reduce the motor size and enhance the motor efficiency for low-speed and high torque applications under the space constraints for propulsion system. Especially, homopolar superconducting synchronous motors (HSSMs) need less superconductor and lower magnetic flux density in superconductor field coil than air-cored superconducting synchronous motors (ASSMs). In addition, mechanical structure is more simplified and stability is increased because the superconductor field coil of HSSMs is not rotated in operation. In this paper, we present the outline of HSSMs including structure, characteristics and operational principles with the conceptual design of 5MW HSSM.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.600-601
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• 2021

The cyberspace, which is the fifth battle field, should be utilized for multi-domain maneuvering between the cyberspace and the physical space using an electromagnetic spectrum. This becomes a major concept of cyber electronic warfare that combines the characteristics of cyber warfare and electronic warfare. In this study, the concept of cyber electronic warfare is analyzed by using the OSI reference model and examining the threats of the two-layer data link layer.