ZCZ 부호를 이용한 상호간섭에 강인한 차량용 확산대역 레이더 방식

김봉석,이종훈,Kim, Bong-seok,Lee, Jonghun 대한임베디드공학회 2016 대한임베디드공학회논문지 Vol.11 No.1

We propose vehicular spread spectrum (SS) radar robust to mutual interference using zero correlation zone (ZCZ) code. SS radar schemes have been employed for vehicular radar systems due to their outstanding correlation property. However, this superiority is based on a premise that timing among codes is completely synchronized. In the practical driving environment, timing mismatch among radar signals is inevitable because the radar signals of several vehicles are independently transmitted at each different location and each timing and thus each radar signal is received at different timing. This timing offset is the main cause of orthogonality destruction among codes and thus radar signals from other vehicles become mutual interference. In order to solve this problem, we find out the new property of ZCZ code which maintains the complete orthogonality except to timing offset corresponding to chips (pulses) of multiple of 4 and employ ZCZ code to SS radar systems. Simulation results show the proposed scheme achieve better performance compared with the conventional SS radar scheme using pseudo code or gold code.

Effect of Mutual Interference and Channel Estimation Error on Outage Performance of Reactive Relay Selection in Unlicensed Systems

Khuong Ho-Van 한국통신학회 2015 Journal of communications and networks Vol.17 No.4

This study addresses the effects of channel estimation error and mutual interference between licensed and unlicensed systems on outage performance of reactive relay selection in unlicensed systems over independent non-identical (i.n.i) Rayleigh fading channels and under both the maximum transmit power constraint and primary outage constraint. Toward this end, power allocation for unlicensed users is first recommended to satisfy both constraints and account for channel estimation error and mutual interference. Then, we derive an exact closed-form outage probability representation for unlicensed systems to quickly evaluate this effect in key operation parameters. Various results corroborate the derived expressions and provide useful insights into system performance.

철도궤도회로시스템에서 동일한 주파수를 사용하는 궤도회로 사이의 이격거리에 대한 연구

김민석(Min-Seok Kim),이종우(Jong-Woo Lee) 대한전기학회 2009 전기학회논문지 Vol.58 No.11

Electrical railway system consists of rolling stock, track, signal and streetcar line system. Track circuit system is a vital system due to checking the location of trains. Track circuits are divided by using frequency and isolated electrically. Currently, there is not a regulation for the distance between track circuits using identical frequency. In case of installing additional track circuits in large stations or marshalling yard, the problem which is that the signal is not exactly transmitted to the track circuit occurs due to the mutual interference. In other words, the track circuit properly is not operated on account of wrong induction current by the mutual inductance between track circuits. In this paper, we suggest the electrical model between track circuits and numerically calculate demanded parameters in electrical model. The distance between track circuits satisfying the mutual inductance which does not happen to the mutual interference phenomenon is presented about the distance of track circuit. It is proved by using Matlab and PSpice program as the amplitude of mutual induced current.

고주파 응용의료기기의 전자파장해․내성 가이드라인 개발 연구

최승선(S. S. Choi),이준식(J. S. Lee),황인호(I. H. Hwang),차지훈(J. H. Cha),허찬회(C. H. Hur),박기정 한국재활복지공학회 2010 재활복지공학회논문지 Vol.4 No.1

의료장비의 발달로 인해 병원에서의 영상진단, 고주파 수술기를 통한 위생적 치료, 고주파 온열기를 통한 암 치료 등 우리 생활에 가까운 곳에서 고주파를 이용한 의료기기들이 넓게 활용되고 있는 시점에 고주파를 이용한 응용기기들 간의 RF상호 간섭 문제에 대한 대책이 미흡한 실정이다. 『그러므로 향후기술개발과 고주파응용 의료기기의 산업발전에 문제가 될 수 있는 요인을 방지하기 위하여 고주파응용의료기기의 사용 현장에서 발생될 수 있는 상호 간섭 문제를 합리적이고 적합한 시험방법개발이 필요하다.』 본 논문에서는 고주파응용 의료기기에 대한 상호 간섭문제를 해결하기위해 전자파 평가를 위한 표준시험방법을 연구하였다. By the development of medical devices, high-frequency medical devices are becoming widely used. Imaging diagnosis in hospital and clean treatment by high-frequency medical devices and cancer treatment through high-frequency heaters around us, all serve as the examples. However, it still lacks the measures to the problems of the RF( Radio Frequency) mutual interference between the high-frequency devices. In order to prevent the problematic factors for technical and industrial development, a new reasonable and suitable test method is required. In this paper, we study a standard test method for EMC evaluation to solve the RF mutual interference.

Mutual Interference on Mobile Pulsed Scanning LIDAR

Kim, Gunzung,Eom, Jeongsook,Choi, Jeonghee,Park, Yongwan Institute of Embedded Engineering of Korea 2017 대한임베디드공학회논문지 Vol.12 No.1

Mobile pulse scanning Light Detection And Ranging (LIDAR) are essential components of intelligent vehicles capable of autonomous travel. Obstacle detection functions of autonomous vehicles require very low failure rates. With the increasing number of autonomous vehicles equipped with scanning LIDARs to detect and avoid obstacles and navigate safely through the environment, the probability of mutual interference becomes an important issue. The reception of foreign laser pulses can lead to problems such as ghost targets or a reduced signal-to-noise ratio. This paper will show the probability that any two scanning LIDARs will interfere mutually by considering spatial and temporal overlaps. We have conducted four experiments to investigate the occurrence of the mutual interference between scanning LIDARs. These four experimental results introduced the effects of mutual interference and indicated that the interference has spatial and temporal locality. It is hard to ignore consecutive mutual interference on the same line or the same angle because it is possible the real object not noise or error. It may make serious faults because the obstacle detection functions of autonomous vehicle rely on heavily the scanning LIDAR.

Mutual Interference on Mobile Pulsed Scanning LIDAR

김건정,엄정숙,최정희,박용완 대한임베디드공학회 2017 대한임베디드공학회논문지 Vol.12 No.1

Mobile pulse scanning Light Detection And Ranging (LIDAR) are essential components of intelligent vehicles capable of autonomous travel. Obstacle detection functions of autonomous vehicles require very low failure rates. With the increasing number of autonomous vehicles equipped with scanning LIDARs to detect and avoid obstacles and navigate safely through the environment, the probability of mutual interference becomes an important issue. The reception of foreign laser pulses can lead to problems such as ghost targets or a reduced signal-to-noise ratio. This paper will show the probability that any two scanning LIDARs will interfere mutually by considering spatial and temporal overlaps. We have conducted four experiments to investigate the occurrence of the mutual interference between scanning LIDARs. These four experimental results introduced the effects of mutual interference and indicated that the interference has spatial and temporal locality. It is hard to ignore consecutive mutual interference on the same line or the same angle because it is possible the real object not noise or error. It may make serious faults because the obstacle detection functions of autonomous vehicle rely on heavily the scanning LIDAR.

지하철 무선환경의 전파간섭 영향 분석 방안 연구

오성균,김문환,김덕원,차재상 사단법인 한국위성정보통신학회 2013 한국위성정보통신학회논문지 Vol.8 No.4

Subway in Korea, most of a metropolitan public transport use only worth ten million people a day floating population ofwireless communication can be considered HOT SOPT. These three operators' 2G/3G/4G / Wi-Fi / T-DMB frequency andthe number of services to co-exist, and the subway train passengers and subway party for operation and management of thecommunication network is also the co-subway passenger safety and for this service for the effects of mutual interferenceof whether the verification was necessary. This research and testing different frequency / communication interference betweenservices and testing to determine whether, through the subway authorities and mobile operators in each frequency-specificinteraction check and there is no interference to the safety and quality of subway passengers communication services thatcan be verified as the data was found. The verification methods in the metro area, not just from one region to determinewhether the interference with a common verification methods can be applied. 지하철은 한국에서 가장 많이 이용하는 대중교통으로 수도권에만 하루 유동인구가 일 천만명에 달하는 무선 통신의 HOT SOPT이라고 볼 수 있다. 여기에는 3개 통신 사업자의 2G/3G/4G/Wi-Fi/T-DMB의 수많은 주파수와 서비스가 공존해 있으며, 지하철 승객과 전철의 통신운용관리를 위한 지하철 자가망도 공존해 있어, 지하철 승객의 안전과 운행을 위하여 이에 대한 상호간의 전파간섭의영향여부의 검증이 필요하였다. 본 연구와 시험은 서로 다른 주파수/통신 서비스 간의 전파 간섭여부를 확인하는 방법과 시험을통하여, 지하철 기관과 이동통신사업자는 각 주파수별의 상호영향 간섭이 없음을 확인하고 지하철 승객에게 안전하고 고품질의 통신서비스를 할 수 있는 검증의 자료로써 확인할 수 있었다. 이러한 검증방법은 지하철 공간에서 뿐만이 아닌 어느 지역에서의 상호간섭여부를 확인할 수 있는 일반적인 검증방법으로 적용이 가능하다.

두 대의 FMCW 레이다에서 레이다간 상호 간섭 신호를 이용한 시간동기화 방법

조병래(Byung-Lae Cho),이정수(Jung-Soo Lee),이종민(Jong-Min Lee),선선구(Sun-Gu Sun) 한국전자파학회 2012 한국전자파학회논문지 Vol.23 No.11

군사적 목적으로 많은 레이다들이 근거리에서 동시에 운용된다. 특히, 동종의 레이다가 동시에 운용될 경우 주파수 할당을 해야 한다. 많은 레이다가 동시에 운용될 때 일부 주파수를 공유하여야 하는데, 부득이하게 레이다 시스템 간 간섭이 발생하게 된다. 레이다간 간섭은 성능을 저하시킬 수 있기 때문에, 간섭 신호의 억제는 중요한 문제이다. 본 논문에서는 두 대의 FMCW 레이다간 간섭 신호를 분석하고, 간섭 신호를 이용하여 레이다간 시간 동기화 방법을 제안하였다. 실제 레이다 시스템을 통해 제안된 방법의 성능을 검증하였다. In military applications, many radar systems are simultaneously operated at a close range. In particular, the frequency allocation must be executed for operating the homogeneous radar systems at the same time. As many radar sytems are simultaneously operated with overlapping frequency bands, interference between systems inevitably occurs. Because interference can degrade radar performance, suppression of interference is a critical issue in radar systems. In this letter, we analyze the interference between two FMCW radars. In addition, time synchronization method between radars using mutual interference is proposed. Experiments are carried out to validate the proposed method. The results demonstrate that the proposed method is suitable for real radar systems.

계약당사자 쌍방에 공통하는 동기의 착오

이선희 ( Sun Hee Lee ) 이화여자대학교 법학연구소 2021 法學論集 Vol.25 No.4

우리 민법은 제109조에 착오취소에 관한 규정을 두고 있지만, 계약당사자 쌍방의 공통하는 동기의 착오는 위 규정이 당초 예정한 경우라고는 보기 힘들다. 이에 송덕수 교수님은 1989년에 발표하신 “계약당사자 쌍방의 공통하는 동기의 착오”라는 논문을 통하여 주관적 행위기초론에 기한 해결책을 제시하였다. 본고는 위 논문의 내용을 살펴보고 위 논문의 논제에 관한 당시와 현재 국내 학설ㆍ판례의 모습을 비교해 보았다. 이로써 위 논문이 논제의 특수성에 대하여 거의 인식조차 하지 못하였던 당시 국내의 학설ㆍ판례에 상당한 반향을 불러일으키고, 대상논제에 대한 많은 연구를 촉발시켰음을 확인할 수 있었다. 필자는 미국법상 착오제도로부터의 시사점을 향후 연구방향으로 잡고, 부실표시를 포함한 착오제도가 취소 외에도 계약의 수정이나 취소, 해지, 손해배상 등의 다양한 구제책을 마련하고 있음을 주목하였다. 이를 통하여도 대상논제를 민법 제109조에 의해서만 해결하려고 하던 종래 우리나라 판례에 대하여, 비판적 입장을 취하고 대안을 제시하셨던 송 교수님의 혜안을 다시금 확인할 수 있다. Article 109 of Korean Civil Code provides for the avoidance of a contract on the ground of a mistake. However, it may be hard to say that the mutual mistakes in motives between contracting parties can be solved by Article 109. In response, Professor Tuck-Soo Song presented a solution by “Interference with the party’s subject basis of the transaction” through his paper “Mutual Mistakes in Motives” published in 1989. I examined the contents of Professor Song’s the above paper and compared the past and current domestic theories and our court’s rulings about that theme. As a result, I could find that the above paper resonated significantly in our academia and courts at the time when little awareness was made of the specificity of that theme and triggered many studies on that subject. I set the implications of the mistake under U.S. law in the direction of future research, and note that mistakes as well as misrepresentations have various remedies such as reformation, avoidance, termination of a contract, or compensation of damages. Through this, I could confirm the insights of Professor Song, who took a critical stance and suggested alternatives to the Korean court’s precedents, which were only intended to solve that subject matter under Article 109 of Korean Civil Code.

2개의 성장 균열들의 상호작용에 관한 응력확대계수 해석

박성완 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.5

In this study, a fundamental approach to make clear the mechanism of the mutual interference and coalescence of stress fields in the vicinity of two crack tips on the process of their slow growth, using boundary element method. Automatic generation of quadratic discontinuous elements along both of the crack boundaries which can be defined by an arbitrary piece-wise straight geometry. The direction of the crack-extension increment is predicted by the maximum principal stress criterion, corrected to account for the discreteness of the crack extension. Along the computed direction, the crack is extended one increment. Automatic incremental crack-extension analysis with no remeshing, computation of the stress intensity factors by J-integral. Numerical stress intensity factors for two growing cracks in plane-homogeneous regions were determined.