• Proceedings of the KSR Conference
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• 2002.10a
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• pp.408-413
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• 2002

From the moment that electricity is applied to a relay, a wheel turned, or a valve opened, the process leading to the need for maintenance begins, The uninitiated will tell you that the Maintenance man is someone who repairs something when it has gone wrong. Unfortunately, in any large engineering concern, such as a railway, it is not possible to work on the principle that only when something breaks down should it get any attention. The failure of one contact, diode or bearing could well stop not only the assembly of which it is a part, but the flow line or process, with loss of revenue, and clientele, and often with effects on the safety of both staff and the traveling public. So, we have to establish the reliable and cost-effective maintenance system to resolve these problems.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.675-682
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• 2006

The command of Subway is intended to adjust and control the train operation, and to play a key role of the total passenger transport and all kinds of affairs related to the safe train operation. Also, this can be considered as affairs to be controlled and operated by Total Traffic Control. For the purpose of developing the ATO system in using the new control technology by substituting the conventional ATS equipment, this technical document includes the technical points resulted from doing the replacement construction in the entire section of Subway Line 2 by Seoul Metro. The replacement work with the new ATO System should neither stop nor affect the system under operation while operating the current ATS System. The different systems should not interfere with each other while performing their individual affairs, and be composed to share the important data for the parallel operation. This technology is needed to proceed in assurance of a high degree of reliability.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.77-81
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• 2011

This paper presents a single-pole eight-throw(SP8T) switch based on proposed a radio-frequency(RF) microelectromechanical systems (MEMS) switches. The proposed switch was driven by a double stop(DS) comb drive, with a lateral resistive contact. Additionally, the proposed switch was designed to have tapered signal line and bi-directionally actuated. A forward actuation connects between signal lines and contact part, and the output becomes on-state. A reverse actuation connects between ground lines and contact part, and the output becomes off-state. The SP8T switch of 3-stage tree topology was developed based on an arrangement of the proposed RF MEMS switches. The developed SP8T switch had an actuation voltage of 12 V, an insertion loss of 1.3 dB, a return loss of 15.1 dB, and an isolation of 31.4 dB at 6 GHz.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.221-229
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• 2010

In recent studies, many methods have been studied for mobile robot using magnetic markers on its pathway. This is not influenced by the weather conditions, and makes possible to develop controller with low level processors and simple algorithms. However, the interval between magnets is restricted by the magnetic field intensity and it is impossible to get road information ahead. This paper suggests a method of widening markers and expressing the road information ahead using magnetic markers, and explains a sensor arrangement considering suggested methods. Also, magnetic field analysis was done to investigate the effects of widening magnetic markers with various environments. A small mobile robot was made to figure out the performance of suggested methods, and driving experiments were performed on the straight and curved road with magnetic markers. The results show that the robot moved the prearranged pathway with 0.5 cm lateral displacements and stopped at a stop line using magnetic information on the road.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.459-467
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• 2017

An urban railway power substation consists of three thyristor dual converters. Two converters are connected to up and down trolley line to supply the electric energy or feed the regenerative energy back to the distribution. When the two converters break down, the remaining converter is used in an emergency. One thyristor dual converter system (TDCS) manages the energy of two or three railway stations. If the TDCS fails, the trains stop operating. To solve the problem, this paper proposes the three parallel operation control algorithm of thyristor dual converter system using the emergency converter. The broken TDCS can be replaced by the emergency converter in other TDCS. The effectiveness of this proposed control is verified by simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2242-2246
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• 2009

In this paper, a homogeneous dual composite right/left-handed (D-CRLH) transmission line (TL) is proposed by using a defected ground structure (DGS) on the ground plane. In order to satisfy a homogeneity condition of metamaterial, a subwavelength unit cell is designed by way of a spiral DGS and a meander stub. From a dispersion diagram, it is expected that the frequency bands for the left-handed (LH) property is 3.5 - 4.4 GHz. At 3.8 GHz in the LH band, backward propagating phenomenon is observed from full-wave analysis. The experimental results show that the proposed TL has a stop-band in 1.75 - 3.6 GHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.93-97
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• 2000

In an era of very rapid technological change, standardization organizations have been confronted with the problem that they should develop more new and more complex standards as strategic tools for enforcement of competitive power in shorter time according to the reduction of Life Cycle of products and the increase in the number of standards and their complexity. To cope with this challenge, we introduce the functionalities and development directions for implementing standardization information system. Also this paper describes the architecture of the next generation system for standard information that enabling information sharing and exchanging using XML. Finally, we suggest implementation framework of Standardization Vortal Site for the One-stop service of integrated standards information which provide users with standards development roadmap and give brief introduction to SOL(Standards On-Line) site which is operated by ETRI/PEC.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.285-285
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• 2011

EUVL (Extreme Ultra Violet Lithography) is one of competitive lithographic technologies for sub-30nm fabrication of nano-scale Si devices that can possibly replace the conventional photolithography used to make today's microcircuits. Among the core EUVL technologies, mask fabrication is of considerable importance since the use of new reflective optics having a completely different configuration compared to those of conventional photolithography. Therefore new materials and new mask fabrication process are required for high performance EUVL mask fabrication. This study investigated the etching properties of SnO2 (Tin Oxide) as a new absorber material for EUVL binary mask. The EUVL mask structure used for etching is SnO2 (absorber layer) / Ru (capping / etch stop layer) / Mo-Si multilayer (reflective layer) / Si (substrate). Since the Ru etch stop layer should not be etched, infinitely high selectivity of SnO2 layer to Ru ESL is required. To obtain infinitely high etch selectivity and very low LER (line edge roughness) values, etch parameters of gas flow ratio, top electrode power, dc self - bias voltage (Vdc), and etch time were varied in inductively coupled Cl2/Ar plasmas. For certain process window, infinitely high etch selectivity of SnO2 to Ru ESL could be obtained by optimizing the process parameters. Etch characteristics were measured by on scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Detailed mechanisms for ultra-high etch selectivity will be discussed.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.5
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• pp.1-9
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• 2010

Generally, dynamic hand gesture recognition is formed through preprocessing step, hand tracking step and hand shape detection step. In this paper, we present advanced dynamic hand gesture recognizing method that improves performance in preprocessing step and hand shape detection step. In preprocessing step, we remove noise fast by using dynamic table and detect skin color exactly on complex background for controling skin color range in skin color detection method using YCbCr color space. Especially, we increase recognizing speed in hand shape detection step through detecting Start Image and Stop Image, that are elements of dynamic hand gesture recognizing, using Guideline. Guideline is edge of input hand image and hand shape for comparing. We perform various experiments with nine web-cam video clips that are separated to complex background and simple background for dynamic hand gesture recognition method in the paper. The result of experiment shows similar recognition ratio but high recognition speed, low cpu usage, low memory usage than recognition method using learning exercise.

• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.37-43
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• 2020

Smartphone-based localization has been widely studied in many different scenarios. But as far as we know, few work has addressed the problem of localization in underground public transportation systems, where GPS signal and wireless infrastructure are not always available. Knowing the location of a train is necessary to develop a useful service for subway passengers. And so, estimation of motion state and stop station by using sensors on a smartphone is being studied for subway passengers. This paper proposes a localization method that uses a barometer and a magnetic sensor on a smartphone. The method proposed in this paper first estimates whether the train runs or stops according to the change in air pressure and the strength of the magnetic field. The altitude value and the magnetic field value are then used to estimate the exact stop station of the train. We evaluated the proposed method using data from the Seoul's subway line 5. Compared with previous methods, the proposed method achieves higher accuracy.