• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.3-13
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• 2013

This paper reviews the characteristics of dilemma zone by analysing the influence exerted by actual location of intersection traffic signal on behaviour of drivers approaching signalized intersection in urban area. The analysis of approach speed was based upon a 'before and after' comparison, measured at three sites where the locations of traffic signals were changed. The study demonstrated that, when traffic signal changed to yellow, the scales of dilemma zone were narrowed in case of stopping cars by moving up the starting point of the dilemma zone due to lowered spot speed. On the other hand, in case of passing cars, the end points of dilemma zone were moved further out to the rear due to increased spot speed. Therefore, changing traffic signal locations could make an impact to increase intersection safety through reducing the scales of dilemma zone. This study also found that, in cases involving vehicles with similar approach speeds, spot speeds could be differentiated following the change of signal locations due to the fact that there can be greater differences in both braking point and deceleration rate. Thus, when considering the appropriate measuring of dilemma zone, 'spot speed' rather than 'approach speed' appeared to be more appropriate criterion.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.390-391
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• 2019

영구자석 동기 전동기의 PI 전류 제어기 이득은 대역폭과 파라미터에 의해 결정된다. 파라미터 추정 시 필요한 전류 제어기 이득을 임의로 설정할 수밖에 없다는 문제가 있다. 본 논문은 정지좌표계에 대해 회전하는 전압 신호를 인가하여 초기 위치를 추정함과 동시에 인덕턴스를 일정 오차 내로 추정하여 빠르게 인덕턴스를 추정하고, 이를 이용해 전류 제어기 이득을 전동기의 전기적 파라미터에 맞게 설정할 수 있는 방식을 제안한다.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.49-56
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• 2002

In this paper, a new controller using non-linear compensator for position control is presented, which we can satisfy the given specifications more easily than the existing one. We suggest an improved PDFE(Integral with Proportional-Derivative-plus-Feedforward) controller by which both phase margin and bandwidth are controlled simultaneously in the controller design problem. Replacing the feed forward term in the PDFF system with a CDIDF(Complex Dual Input Describing Function), the desired phase margin is obtained without diminishing the bandwidth of the closed loop system. The effectiveness of the proposed controller is confirmed through simulations and experiments. As The results of these, we know that it is possible to adjust overall specifications by varying parameters in the improved PDFF system.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.38-43
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• 2015

This paper describes a GPS signal generator that can generate multiple satellite signals in real time at the RF level. It realizes the verified software algorithm on a FPGA. The algorithm models orbits and environmental errors such as ionospheric and tropospheric multipath. The position of a simulated receiver is one of simulation parameters. The hardware which consists of a digital logic board and an analog board can generate 16 simulated satellites signals at the same time. The users can generate spoofing signals and jamming signals as well as satellite signals by using the windows-based control software. In addition, the software provides GIS-based simulation scenarios editing tools. We verified the generator by using commercial receivers. As an application, we configured generators as indoor positioning systems and tested them in a building. To improve the accuracy of indoor systems is our further study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7C
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• pp.592-600
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• 2012

In this paper, we proposed that decentralized frequency allocation scheme(DFAS) without network entry procedure between relays in mobile relay system. Frequency Indicator(FI) signal which is the reference signal of frequency division of each relay and Energy Detection(ED) region are defined. In addition, the mobile connected to the relay transmits the FI signal to neighbor relays in order to facilitate communication between relays. Finally, by using this scheme, the cell throughput improvement is confirmed.

• Journal of Korean Society of Transportation
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• v.14 no.2
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• pp.59-88
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• 1996

This study has determined optimal type, and location of loop detector to measure accurately traffic condition influenced by traffic variation with real time. Optimal type of loop detector for through vehicle at stop bar was determined by confidences of occupancy period, and nonoccupancy period, and so appropriate detector type for application to real time traffic control system has been decided on special loop detector.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.273-280
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• 2000

Channel characteristics between the outdoor transmitter far away from the building and receivers inside the building are explored theoretically using ray tracing technique. In this paper, 29 receivers are located on the single floor of the building to observe the variation of channel properties depending on receiver location. For each receiver, amplitudes and phases of ail the possible rays form the transmitter to the receiver are traced to obtain impulse response. Statistical results for rms delay spread and power delay profiles for representative receiver location are given.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.421-424
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• 2012

본 논문은 실내 공간에서 RFID와 센서를 이용하여 이동로봇이 자기 위치를 파악하고 목표물체를 인식할 수 있는 기법을 제안한다. RFID를 지면과 목표물체에 설치하고 로봇은 리더기와 다양한 센서를 갖춤으로써 이동시 자기 위치를 파악하고 물체로부터도 고유정보를 얻을 수 있게 구성하였다. 초음파 센서 신호의 귀환시간을 활용하여 전방 물체의 거리를 추출하며 바닥의 RFID로부터 이미 획득한 자기 위치를 활용하여 물체의 절대 위치를 구한다. 이는 로봇을 중심으로한 경로지도를 실시간으로 작성하는 것이 가능하며, 실내의 구조 및 목표 물체의 위치등을 포함한 전체적인 지도를 작성할 수 있다. 최종적으로는 최적의 경로계획을 세워 로봇이 목표 위치로 이동하거나 자율적 탐색이 가능하도록 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.249-252
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• 2011

본 논문은 실내 공간에서 RFID와 센서를 이용하여 이동로봇이 자기 위치를 파악하고 목표 물체를 인식할 수 있는 기법을 제안한다. RFID를 지면과 목표물체에 설치하고 로봇은 리더기와 다양한 센서를 갖춤으로써 이동시 자기 위치를 파악하고 물체로부터도 고유정보를 얻을 수 있게 구성하였다. 초음파 센서 신호의 귀환시간을 활용하여 전방 물체의 거리를 추출하며 바닥의 RFID로부터 이미 획득한 자기 위치를 활용하여 물체의 절대 위치를 구한다. 이는 로봇을 중심으로한 경로지도를 실시간으로 작성하는 것이 가능하며, 실내의 구조 및 목표 물체의 위치등을 포함한 전체적인 지도를 작성할 수 있다. 최종적으로는 최적의 경로 계획을 세워 로봇이 목표 위치로 이동하거나 자율적 탐색이 가능하도록 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1477-1486
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• 2013

In this paper, Implementation of location estimation system using wireless communication technology based on Zigbee. Using wireless communication technology, calculation more accurate location information and service location information to the H/W and S/W has been developed. Receivers, repeaters, smart tag(location device), was developed for implement a location estimation system. The smart tag is built the 120~130KHz, 13~14MHz, 2.0~3.0GHz radio frequency tag. Receiver and repeater is applied to the tag module to recognize the location device's active RFID tags transmit a wireless signal for tag identification. Common Entrance control system in contact with a smart tag, It was implemented to transfer the value of the tag to the access control server over a LAN.