• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.757-766
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• 2005

A speed of a train is controlled by Automatic Train Control system and the continuous transmission system provide the speed related information in the Korean High Speed Line. The primary objective of this paper is to measure the level of continuous signal and to calculate the message of that signal. A measuring equipment is introduced and the equipment provide the base line of the level of current and the correction information of the message.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1877-1882
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• 2000

In this paper, an integrated system for dynamic analysis and optimal design of engine mount systems is presented. The system can simulate static and dynamic behaviors of engine mount systems and optimize design parameters such as mount stiffness, mounting locations with desired design targets of frequency or displacement. A FF-engine with an automatic transmission is used to demonstrate the analysis and optimal design capabilities of the proposed design system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.2017-2022
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• 2009

Sinbundang Line(SBL) Train moves the transition zone where is located between Jeongja station and Migeum station switched over from Communication Based Train Control (CBTC) system area to Automatic Train Control (ATC) system area and viceversa. The SBL train to move the between SBL and Bundang Line is needed to install the Specific Transmission Module (STM) on SBL Line for interface with Bundang Line; STM receives from speed code from Bundang Line. So we suggested the method to ensure mutual compatibility and reliability for train operation on each other signaling system.

• 대한기계학회논문집B
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• 제20권1호
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• pp.284-294
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• 1996

In this paper, dynamic characteristics of an AT clutch system were investigated considering the dynamics of check ball and hydraulic control valves. Dynamic model of a pressure control solenoid valve (PCSV) was obtained by Bondgraph and permeance method. Also, the clutch piston and check ball dynamics were modeled by considering the effect of centrifugal force of the oil entrapped in the clutch chamber. In order to validate the dynamic models obtained, plunger displacement of PCSV and pressure response of the clutch supply lines were compared with the available experimental data, which were in good accordance with the numerical results. Using the dynamic model of the clutch system, simulations were performed to investigate the effect of the rotational speed on the response of clutch cylinder pressure, clutch piston and check ball displacement, and oil flow rate into the cylinder and flow rate out of the check valve.

• Journal of Communications and Networks
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• 제7권1호
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• pp.36-44
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• 2005

In this paper, we present a retransmission power adjustment (RPA) scheme for DS/SSMA ALOHA packet radio systems with packet combining. In the proposed RPA scheme, retransmission power is adjusted in such a way that the erroneously-received packet can be recovered with a minimized interference to other user packets. We analyze the performance of the system with the RPA by employing the equilibrium point analysis (EPA), and confirm that the results obtained from the EPA are very close to the simulation results in low power cases. Simulation results demonstrate that the RPA scheme brings forth performance gain in the throughput and the average delay while saving a significant amount of transmission power. We also investigate the stability of the system from the EPA results, and conclude that the system becomes stable as the offered load increases or the level of retransmission power decreases.

• 전기의세계
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• 제17권4호
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• pp.18-27
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• 1968

Analysis of the transient stability of power systems following disturbances involves many sets of non-linear differential equations. This paper attempts to analyze the transient stability of multi-machine power systems by the step by step method, using the electronic digital computer. The critical switching times and phase angles for the main 154KV transmission system in Korea, are given from the swing curves of the probable conditions. It is concluded that the system is, in general, stable if the relay is cut off within 12 cycles after the fault. However the fault of DAEGU-SANGJU branch, accompanying much real power, makes the system unstable when the raly is cut off within 4 cycles after fault or automatic voltage regulators are equipped in this branch.

• International Journal of Computer Science & Network Security
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• 제22권8호
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• pp.1-6
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• 2022

In this paper, we will present the realization of a facial recognition system using the ESP32-CAM board controlled by an Arduino board. The goal is to monitor a remote location in real time via a camera that is integrated into the ESP32 IOT board. The acquired images will be recorded on a memory card and at the same time transmitted to a pc (a web server). The development of this remote monitoring system is to create an alternative between security, reception, and transmission of information to act accordingly. The simulation results of our proposed application of the facial recognition domain are very efficient and satisfying in real time.

• 한국시뮬레이션학회논문지
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• 제21권3호
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• pp.1-9
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• 2012

본 논문에서는 공항 정밀접근 항공기의 안전성을 증대시키기 위한 방법으로 S/W 패킷모뎀을 이용한 PAR 관제 자동화 방안을 제안하고, DEVS 형식론을 이용하여 제안하는 시스템의 기능을 검증하였다. 기존의 PAR 관제는 음성으로 항공기를 통제함으로써 조종사의 정보 획득 능력이 떨어질 수 있다. 이를 해결하기 위하여 디지털 신호에 의한 자동 관제 시스템을 제안하고, 공항의 PAR이 추적하고 있는 항공기의 비행경로, 강하각, 거리를 조종사에게 실시간으로 전송해 주고 일반화함으로서 관제사의 숙련도와 관제 특성에 기인하는 요소를 배제할 수 있다. 제안된 시스템의 동작을 검증하기 위하여 확장된 DEVS 형식론인 C-DEVS 형식론을 사용하고, 하나의 모델로 합성된 원자 모델을 통해 시스템의 전체 상태 시퀀스를 검색하여 시스템의 안전성(Safeness)과 필연성(Liveness)을 검증할 수 있다. 제안하는 시스템의 C-DEVS 모델을 기존의 음성 관제 시스템과 비교하여 두 시스템이 동일한 상태 시퀀스를 가짐을 확인하였으며, 모든 상태를 검증함으로써 실제 상황에 적용할 수 있을 것으로 생각된다.

• International Journal of Computer Science & Network Security
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• 제23권5호
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• pp.172-178
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• 2023

In this paper, performance of autoencoder based OFDM communication systems is compared with IEEE 802.11a Wireless Lan System (Wi-Fi). The proposed autoencoder based OFDM system is composed of the following steps. First, one sub-carrier's transmitter - channel - receiver system is created by autoencoder. Then learning process of the one sub-carrier autoencoder generates constellation map. Secondly, using the plural sub-carrier autoencoder systems, parallel bundle is configured with inserting IFFT and FFT before and after the channel to configure OFDM system. Finally, the receiver part of the OFDM communication system was updated by re-learning process for adapting channel condition such as multipath channel. For performance comparison, IEEE802.11a and the proposed autoencoder based OFDM system are compared. For channel estimation, Wi-Fi uses initial long preamble to measure channel condition. but Autoencoder needs re-learning process to create an equalizer which compensate a distortion caused by the transmission channel. Therefore, this autoencoder based system has basic advantage to the Wi-Fi system. For the comparison of the system, additive random noise and 2-wave and 4-wave multipaths are assumed in the transmission path with no inter-symbol interference. A simulation was performed to compare the conventional type and the autoencoder. As a result of the simulation, the autoencoder properly generated automatic constellations with QPSK, 16QAM, and 64QAM. In the previous simulation, the received data was relearned, thus the performance was poor, but the performance improved by making the initial value of reception a random number. A function equivalent to an equalizer for multipath channels has been realized in OFDM systems. As a future task, there is not include error correction at this time, we plan to make further improvements by incorporating error correction in the future.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.856-859
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• 2013

선박을 비롯한 해상에 설치된 항로표지용 등대 및 부이 등은 AIS(Automatic Identification System)를 탑재하고 있으며, 이를 이용하여 항해 및 기상 정보 등에 관한 메시지를 송수신한다. 연안의 VTS 센터나 주변 선박들은 이러한 AIS 메시지는 수신하여 그 정보를 활용함으로써 안전한 항해를 할 수 있다. 또한 AIS 메시지는 일반 사용자에게도 공개되어 있는 특징이 있으며, 이러한 특징을 이용한 많은 연구가 진행되고 있다. 이 논문에서는 이러한 AIS의 특징을 이용하여 연근해의 교통 정보를 비롯한 기상 정보까지도 고려한 정보 관리 시스템을 설계한다. 설계하는 시스템은 수집된 정보를 처리하여 다단 데이터베이스에 저장하며, 전자해도를 기반으로 저장된 정보를 시각화해주어 분석 및 통계 작업에 활용할 수 있도록 해준다.