• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.892-899
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• 2006

In this paper, we propose an automatic switching technology between the ad-hoc and the infrastructure modes without user intervention in the IEEE 802.11b wireless LAN. Also, we design our proposed technology and implemented on the Linux machine. For this operation, the area within an Access Point (AP) coverage is defined as a switching area, and a node without any transmission in this area is assumed to be able to relay frames between the AP and nodes in the shaded area that is outside the coverage and cannot reach the AP. By using the proposed technology, it is possible to provide the seamless Internet access service to nodes at the ad-hoc mode in the shaded area. In this paper, we explains the operation of the detection method of the switching area, presents the flowchart and implementation environment. To prove the operation of our technology, we obtain the results of captured packets transmitted between nodes and throughput results through ftp transmission experiment. Hence, we can see that our proposed scheme can be improve the wireless access service in wireless and mobile networks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2125-2130
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• 2010

The neutral section on electric railway system is significant sector in order to prevent short circuit of two electric powers. However, while electric trains pass the neutral section, those speed is decreased and the accident of AC electric traction system and the electric train would be occurred. So the countermeasures are urgently needed. The automatic power switching technology system that is current being research and development is system to improve these problems. Because main object of this system is power change using static switch in the neutral section, it's expected to cause a variety of transients. Especially, onboard transformer inrush current for electric railway train can be occurred more than rated current according to switching time. Therefore, the analysis and improvement are needed to ensure the stability of this system. In this paper, we analyze the operating characteristics of the automatic power switching technology system. Especially, it reviews inrush current according to the closing phase angle. And we propose control plan of inrush current considering the case that voltage is maintained due to counter electromotive force and regenerative braking operation of electric railway train. Finally, the proposed control scheme was reviewed using the transient analysis program.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.9-14
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• 2013

The monitoring system is an absolutely required system for improving a performance to consider the situation for the hybrid generation of the photovoltaic (PV) and wind power (WP) energy experimental research complex. This system is to monitor with the railroad switching point heating system using LabVIEW to the hybrid generation of the PV and WP. The monitoring system of this paper is a program monitoring the hour, day and total of the voltage and current that made from the hybrid generation of PV and WP. In experiment, we acquired the power data according to time at the day of PV and WP. We have confirmed the possibility of the real time monitoring system using LabVIEW with the railroad switching point heating system as the hybrid generation of the PV and WP.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.30-35
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• 2021

In this study, we developed an automatic module changer for agricultural implements for using in unmanned agricultural robots. An automatic module changer is attached by lowering from the top to bottom of the implements and fixing the four fastener bars attached to the implements in combination. The lift function was implemented using seesaw-type structures to keep the engagement point constant when the automatic module changer climbs and descends, and the switching function of the automatic module changer was implemented using the link device in the cam structure. We developed an algorithm to check the presence of attachment and opening/closing of the workpiece using limit switches and verified the performance through combination assessment and weight lift test to assess whether the combination was within the error range.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.68-74
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• 2008

Ethernet is the very successful technology in private local area network. Therefore, we can obtain the advantage to reduce network overhead due to such as protocol translation when to apply Ethernet to the public backbone network. However, in order to do that, it is required to restore the network within 50msec when link failure occurs, in order to provide seamless connections to end users. Currently, ITU-T standardized the automatic protection switching (APS) based Ethernet protection switching system. In this paper, we propose the improved Ethernet protection switching system to minimize the number of Ethernet frames lost when the network is restored from the failure. The proposed mechanism is analyzed by using simulation based on ns-2 and numerical results show that the proposed one provides superior performance.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.498-506
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• 2010

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch on condition. This project has a goal to develop the automatic changeover system using by noncontactless semiconductor device in neutral section of catenary system so that the train pass as notch-on condition. In this first year, we obtain as following results such as domestic and international systems applications and completion requirements, development and analysis of stability for automatic changeover system, design of static switching device on automatic changeover system in neutral section and drawing up interface design and specifications according to equipment.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.256-267
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• 2014

An automatic switch among ensembles of clustering algorithms is proposed as a part of the bibliographic big data retrieval system by utilizing a fuzzy inference engine as a decision support tool to select the fastest performing clustering algorithm between fuzzy C-means (FCM) clustering, Newman-Girvan clustering, and the combination of both. It aims to realize the best clustering performance with the reduction of computational complexity from O($n^3$) to O(n). The automatic switch is developed by using fuzzy logic controller written in Java and accepts 3 inputs from each clustering result, i.e., number of clusters, number of vertices, and time taken to complete the clustering process. The experimental results on PC (Intel Core i5-3210M at 2.50 GHz) demonstrates that the combination of both clustering algorithms is selected as the best performing algorithm in 20 out of 27 cases with the highest percentage of 83.99%, completed in 161 seconds. The self-adapted FCM is selected as the best performing algorithm in 4 cases and the Newman-Girvan is selected in 3 cases.The automatic switch is to be incorporated into the bibliographic big data retrieval system that focuses on visualization of fuzzy relationship using hybrid approach combining FCM and Newman-Girvan algorithm, and is planning to be released to the public through the Internet.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.4
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• pp.290-295
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• 2016

This paper proposes a new method for the automatic detection of atrial fibrillation (AF), using Markov regime switching GARCH (1, 1) model. The proposed method is based on the observation that variability patterns of heart rate intervals during AF significantly differ from regular patterns. The proposed method captures the different patterns of heart rate intervals between two regimes : normal and AF states. We test the proposed method using Massachusetts Institute of Technology-Beth Israel Hospital (MIT-BIH) atrial fibrillation database, and demonstrate the effectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.238-242
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• 2004

The paper describes an automatic frequency control current-fed inverter for forging applications. The IGBT in series with diodes as its switching devices in the inverter circuit which is of full-bridge type. The operating frequency is automatically tracked to maintain a small constant leading phase angle when load parameters change. The load voltage is controlled to protect the switches. The output power can be adjusted by varying the input current from phase controlled rectifiers which is a part of current source. The system has been operated at 15-17 kHz. The output power transferred to the load is 1,595 watts. It can heat the steel work pieces with 15 mm diameter and 120 mm long from room temperature to approximately 1100 $^{\circ}C$ within 20 seconds with 0.97 leading power factor on the input side.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.63-72
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• 2002

In Korea, a need of automatic dairy farm management system has been increased to lower production cost and to strengthen international competition. However, the present management system was mostly relied on foreign technologies and caused some problems in post management and after-sales services. Therefore, though there is a problem of price and quality at present, domestic technologies of the management system should be developed for the long run. This study was conducted to develop an electronic identification unit for an automatic dairy farm management system. The developed system was consisted of a tag, a reader, a switching circuit, and a personal computer. The tag attachable to each individual cow was developed to transmit individual radio frequency(RF) code into the air with modulation of ASK(amplitude shift keying). And the switching circuit was added to avoid confusion on reception and transmittance. The reader attached to a feeding device was developed to transmit activating signal periodically and to identify code of the individual tag when the tag was approached to the device. The reader was consisted of an active filter, a detecter, a comparator and a microcontroller. The test result was feasible enough to apply it for the automatic farm management system and the identified maximum distance was about 37cm.