• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.663-669
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• 2011

In this study, the optimal length of left-turn lane in permissive left-turn signal system at the signalized intersection which has a left-turn bay is estimated. It is a simulation analysis using the queueing theory that estimate the length of left-turn lane. Traffic density conform to the standards of operating a permissive left-turn system of the Practical Manual Traffic Safety Facilities. And each of a left-turn arrival rate, a left-turn service rate, left-turn average queueing time, for green time average queueing vehicle, for red time average queueing vehicle and average queueing vehicle cycle is calculated. As a result of this study, we would learn how much the space should be secured at the signalized intersection which has a left-turn bay. The methodology using the queueing theory to work out the optimal length of waiting lane in the permissive left-turn signal system was presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1531-1538
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• 2015

In this paper, we proposed receiver structure based on an iterative turbo equalization to cope with phase difference between two sensors in MIMO underwater communication channel. In a space-time coded system, it is often assumed that there are no phase errors among the multiple transmitter and receiver chains. In this paper, we have studied the effect of the phase errors between different transmit sensors and different propagation paths in the environment of MIMO underwater communication system, and have shown through BER performance by computer simulations that the bit-error-rate performance can be severely degraded. A decision-directed estimation and compensation algorithm has been proposed to minimize their effects on the system performance. In this paper, we investigate the phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for underwater channel model to minimize their effects.

• Analytical Science and Technology
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• v.18 no.6
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• pp.483-490
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• 2005

Mass resolution of the time of flight aerosol mass spectrometer for an aerosol component analysis depends on the initial direction and the initial energy of the ions. We have found that the shape of the optimum post focusing electric field is not linear. The maximum electric potential should be applied to the ions whose initial direction is 90 degree. To check on the post focusing effects, we have installed a laser ablation mass spectrometer. By using this LA-MS, we have found that the average energy distribution of the laser ablated ions is 8 eV. To establish the optimum mass resolution, a time delay and a high voltage are needed, and the results of the study show that 1500 nsec, and 3.7 kV are the optimum parameters for our system respectively. The isotope mass signals of copper show a good resolution.

• Convergence Security Journal
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• v.6 no.1
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• pp.33-43
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• 2006

RFID System has an advantage that it need not touch an objects for identification of many objects. Because it is working through wireless communication. Also, So many objects can be identified with RFID System at once. However, although RFID System has convenience like above, it has serious privacy concern at the same time. If RFID System is working with an target object through wireless communication, other objects will respond to RFID System signal as well as a target object. Hence, RFID System can be easily exposed user privacy by attacker. In this paper, We propose RFID system authentication model in order to protecting user privacy and traking. Proposed RFID system is operating that not only server authenticate RFID reader but also RFID reader and tag authenticate mutually by using symetric cryptography that operating with tiny and simple processing.

• Korean Management Science Review
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• v.29 no.3
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• pp.1-11
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• 2012

This paper considers a localization problem in time difference of arrival (TDOA)-based radio frequency identification (RFID) systems. To estimate the position of a target tag, this paper suggests three localization algorithms that use benchmark tags. The benchmark tags are the same type as the target tag, but either the locations or distance of the benchmark tags are known. Two algorithms use the benchmarks for auxiliary information to improve the estimation accuracy of the other localization algorithms such as least squared estimator (LSE). The other one utilizes the benchmarks as essential tags to estimate the location. Numerical tests show that the localization accuracy can be improved by using benchmark tags especially when an algorithm using the LSE is applied to the localization problem. Furthermore, this paper shows that our benchmark algorithm is valuable when the measurement noise is large.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.1
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• pp.9-16
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• 2005

Accurate and reliable tracking of train is essential for the train control system. The fixed block system which utilizes track circuit has been used widely for the detection of train position. As an alternative, the moving block system has the advantage over the fixed block system since it enables shorter headway and easier maintenance. This paper presents a new technique for the train tracking system which uses radio signal for the train position detection. The proposed algorithm uses the phase difference of arrival of radio signal for the detection of train position. Experimental verification of the algorithm is presented in the paper.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.191-194
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• 2009

유엔의 통계에 의하면, 2020 년에 전세계 60 세이상의 인구는 10 억까지 달성하고, 2050 년, 전세계에 20 억 가까운 노인 인구가 생존하게 됩니다. 끊임없이 증가되는 세계의 노령화 문제 때문에, 혼자 생활하는 독거 노인은 끊임없이 증가하고, 동시에 노인들의 순환기질환 관련 위험성은 증대하고 있다. 따라서 본 디자인연구는 이러한 노인들의 문제를 해결하기 위해 외형은 손목 시계와 같이 손목에 차는 형태로 연구되었으며, 심장과 혈압 항상 검사 측정하는 기능이 있어서, 그 수치가 안전을 위협하고 있을 때, 119 나 친척들 또는 담당의사에게 전화로 응급처리를 요청하게 되고, GPRS 는 스스로 작동, 병원에 응급조치와 함께 가장 짧은 시간에 도착할 수 있도록 것을 한다. 동시에 제품에는 환자의 진료카드가 있어 담당의사가 아니라도 진료를 할 수 있도록 하는 기능을 가진 기기에 대하여 연구하였다. 이러한 기기가 노인들에게 사용되기 위해서는 노인의 특성을 고려한 특징적인 연구가 필요하며, 노인의 감성에 맞는 기기의 특성을 파악 적용하는 문제를 연구하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.01a
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• pp.151-152
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• 2020

4차 산업혁명의 핵심으로 떠오르고 있는 드론 산업의 성장속도가 점차 빨라짐에 따라 드론 활용도가 점차 높아지고 있다. 물류시장의 화두는 신속한 배송이지만 기존 택배 및 우편물 등을 배송하기에는 도로의 교통상황에 따라 시간이 많이 들고 인력비와 수송비등 자원이 많이 필요하다. 본 논문은 기존의 택배 시스템에서 사람이 직접 이동해서 물건을 전달하는 방식이 아니라 드론을 이용하여 효과적으로 배송할 수 있는 방법을 제안하고자 한다. 드론을 원하는 목적지까지 보내는 과정에서 발생하는 여러 돌발 상황을 대처할 수 있도록 GPS 및 아두이노기반의 여러 센서들을 이용하여 안정적으로 제어하는 것이 본 논문의 목적이다. 그 외 문자알림 서비스를 이용하여 택배의 실시간 위치를 알 수 있게 하고 도착알림 등을 받게 하여 편리성을 높이는데 역점을 두었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5372-5378
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• 2012

In this paper, we propose a new method to quickly deinterleave the stagger PRI signals and D&S(Dwell and Switch) PRI signals from the EP radar using the electronic warfare system. While former algorithms were based on stochastic methods only using the first deviation of the TOA of radar signals, this paper uses the first and the second deviation of the TOA of radar signals to deinterleave multiple PRIs of EP radars. When we simulate multiple PRIs of EP radars and test the simulated radar signals using the proposed algorithm, various PRI signals such as fixed, jitter, D&S and stagger PRI are well deinterleaved in a short time. This algorithm is found to be very useful for electronic warfare systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.171-173
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• 2022

The 4th industrial revolution technology is developing people's lives more efficiently. GIS provided on the Internet services such as traffic information and time information makes people getting more quickly to destination. National geographic information service(NGIS) and each local government are making basic data to investigate SOC accessibility for analyzing optimal point. To construct the shortest distance, the accessibility from the starting point to the arrival point is analyzed. Applying road network map, the starting point and the ending point, the shortest distance, the optimal accessibility is calculated by using Dijkstra algorithm. The analysis information from multiple starting points to multiple destinations was required more than 3 steps of manual analysis to decide the position for the optimal point, within about 0.1% error. It took more time to process the many-to-many (M×N) calculation, requiring at least 32G memory specification of the computer. If an optimal proximity analysis service is provided at a desired location more versatile, it is possible to efficiently analyze locations that are vulnerable to business start-up and living facilities access, and facility selection for the public.