• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1407-1412
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• 2004

Impedance calculations of electric railway traction systems is essential to define characteristics and to design it. The self impedance is defined voltage drop rate per unit length, the mutual impedance is represented as a voltage induced to transmission line from transmission line. The self and the mutual impedance are influenced by ground return currents. The earth is considered as a semi-infinitely extended non-ideal conductor. The current of transmission line produces earth current induced magnetically and it flow through a path having minimum impedance. Carson proposed the impedance calculation formula using wave equations and magnetic field equations. Though the formula have an improper equation, that is still used as a standard impedance calculation method. This paper introduced an impedance calculation method that the complex depth of earth return method assumes that the current in conductor returns through an imagined earth depth path located directly under original conductor at a depth of. In this paper, we showed that this proposed method has a closed form and is easier than Carson's.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.3
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• pp.33-40
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• 2013

The rural traditional houses in Taebaek mountainous regions play important roles in figuring out values and social aspects of past time including housing life. But due to the introduction of convenient facilities in the current housing life style after industrialized society, many transformations have been taken place even to exist rural traditional folk houses such as installation of new equipment and furniture, the arrangement and function change of rooms, expansion of residential area and etc. So this study aims to secure basic data to prepare installation standard of the convenient facilities as examining convenience facility installation status of the cultural asset designated as rural traditional house, and to identify the meaning and usage of major room of rural traditional houses in order to prepare the proper balances between its original form preservation and residents' convenience living.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.785-788
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• 1993

This paper presents the prototype framework for automated integration of CMOS current-mode fuzzy logic circuits using an intelligent module approach. The library of modules representing the standard fuzzy logic operators was built. These modules were finally used to synthesized sophisticated fuzzy logic units. Fuzzy unit designs were made based upon the results of a newel methodology of the current mirror-based fuzzy logic function synthesis. This methodology is actually incorporated into the presented framework. As an example, the membership function unit was synthesized, simulated, and the final layout was generated using the presented framework. Finally, the fuzzy logic controller unit (FLC) was generated using the proposed framework. Simulation as well as measurement results show unquestionable advantages of the proposed fuzzy logic function integration system over the classical design methodology with respect to the area, relative error and performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.320-324
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• 2011

A digital technique is adopted to calibrate the current mismatch of the charge pump (CP) in phase-locked loops. A 2 GHz charge pump PLL (CPPLL) is used to justify the proposed calibration technique. The proposed digital calibration technique is implemented simply using a counter. The proposed calibration technique reduces the calibration time by up to a maximum of 50% compared other with techniques. Also by using a dual-mode CP, good current matching characteristics can be achieved to compensate $0.5{\mu}A$ current mismatch in CP. It was designed in a standard $0.13{\mu}m$ CMOS technology. The maximum calibration time is $33.6{\mu}s$ and the average power is 18.38mW with 1.5V power supply and effective area is $0.1804mm^2$.

• Proceedings of the KIEE Conference
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• summer
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• pp.965-967
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• 2004

In this paper, characteristic analysis of PC(Pancake Coil) probe with the size variation is presented for eddy current testing. Characteristics of probe are numerically calculated by using the finite element method. From the numerical analysis, the optimum frequency and groups for an experiment are selected. Probes are made and experiment is performed. From the experimental results, the probe shows maximum sensitivity when the size of defect is equal to the size of probe and when the inside diameter is similar to the width of probe and when the height is low. The result can be helpful to the standard of design of PC probe for eddy current testing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.437-443
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• 2008

We have developed an evaluation technique for both ratio error and phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors. By applying this technique to equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured ratio errors (or phase displacements) in the CT comparator. Thus we can evaluate ratio errors and phase displacement of CT comparator by comparing the calculated and measured ratio errors (or phase displacements). The method was applied to CT comparator under test with the ratio errors and phase displacement ranges of $0{\sim}{\pm}10%$ and $0{\sim}{\pm}7.5$ crad, respectively. Finally we have compared the ratio error and phase displacement of the CT comparator obtained in this method with specifications of two companies.

• Health Policy and Management
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• v.2 no.2
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• pp.152-178
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• 1992

This study focuses on making recommendations for the improvement of poor emergency medical services or EMS in Korea. Problems of the current EMS system is widely reviewed. As an alternative of the current system, a franchises system is introduced to EMS. A feasibility study of the new system is carried out as follows. 1) The current EMS system shows such problem as; - Inadequacy of emergency medical fee schedule, - Shortage of emergency medical resources, - Concentration of emergency medical facilities in metropolitan area, - Unestablishment of training program for emergency personnel, - Inappropriateness of patients' behvaviro pattern in emergency care system. 2) Recommendations for the improvement of EMS are as follows: - Well organized communication and transportation system needs to be established by utilizing all the availabl EMS is to be devised for the provision of appropriate emergency care. - A franchises system can be widly adopted so that private organizations are willing to establish a free standing emergency center. - Emergency care fee schedule of the franchises system needs to be appropriate for the system to provide high standard medical services.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.209-217
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• 1999

A catenary system should be designed to be an uniform elasticity over a span in order to maintain the lowest possible loss of contact between a pantograph and a contact wire. A elasticity disuniformity of a catenary can be regarded as a important design factor used for predicting the current collection performance for a catenary. There are a couple of formulas to calculate elasticity disuniformity of a catenary according to the literature survey, The effectiveness of these formulas is reviewed by performing catenary elasticity and loss of contact analysis for 5 different configurations of catenary systems using a beam element based FEM program, KRRI developed program, and the loss of contact by GASENDO, RTRI developed program, respective]y. The results reveals that these formulas are not suitable to predict the current collection performance for a catenary. Therefore, a new formula based on the standard deviation of the elasticity over a span is proposed in this study. The analysis results show that the new formula for an elasticity disuniformity of a catenary is very effective in predicting the current collection performance for a catenary.

• Journal of Information Technology Services
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• v.22 no.4
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• pp.21-35
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• 2023

Software as Medical Devices (SaMD) is a growing category of medical devices that are composed of software to perform one or more medical purposes. SaMD is less likely to cause physical harm compared to conventional medical devices, particularly medical electrical equipments, and may be more vulnerable to privacy issues. This difference was acknowledged and resulted in introducing new regulation guidance specifically for cybersecurity of SaMD. It guides stakeholders of SaMD what to consider in what context in terms of cybersecurity. This study examines the current guidance of how cybersecurity is considered for SaMD by analyzing current medical device standards, then suggest which concept or details beyond current medical device standards may be applicable through analysis of international standards documents published for software in general.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.520-526
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• 2005

Automation in construction has been restricted to special classes of tasks. Curtain walls can be handled like standard construction materials; they are heavy but breakable, and are large but require precise installation. These characteristics make the installation of curtain walls ideal for robotic automation. There are two methods for developing construction robots: The first is approving the robot performance and applying it to the current construction methods. The second is admitting the limitation of the current robot technology and trying to optimize the current method of construction to apply the robot system. In this study, we derived the performance requirements of a curtain wall-installation robot. We also tested this robot at a real construction site and evaluated its performance. Finally, the results were analyzed, and we proposed additional research.