• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.771-773
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• 2014

본 논문에서는 장거리 레이더용 차량 충돌 방지 77-GHz CMOS 믹서를 제안한다. 이러한 회로는 2볼트 전원전압에서 동작하며, 저 전압 전원 공급에서도 높은 변환 이득과 낮은 변환 손실 및 낮은 잡음지수를 가지도록 설계되어 있다. 제안한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정($f_T/f_{MAX}=120/140GHz$)으로 설계하였다. 전체 칩 면적을 줄이기 위해 수동형 인덕터 대신 전송선(Transmission Line) 을 이용하였다. 본 논문에서 설계한 믹서는 약 5.2dB의 우수한 변환이득 특성과 2.1dBm의 우수한 IIP3 특성을 보였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.35-46
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• 2006

When an RFID reader attempts to read the tags, interference might occur if the neighboring readers also attempt to communicate with the same tag at the same time or the neighboring readers use the same frequency simultaneously. These interferences cause the RFID reader collision. When the RFID reader collision occurs, either the command from the reader cannot be transmitted to the tags or the response of the tags cannot receive to the reader correctly, Therefore, the international standard for RFID and some papers proposed the methods to reduce the reader collision. Among those, Colorwave and Enhanced Colorwave is the reader anti-collision algorithm using the frame slotted ALOHA based a TDM(Time Division Multiplex) and are able to reduce the reader collision because theses change the frame size according to a collision probability. However, these can generate the reader collisions or interrupt the tag reading of other readers because the reader that collides with another reader randomly chooses a new slot in the frame. In this paper, we propose a new RFID reader anti-collision algorithm that each reader monitors the slots in the frame and chooses the slot having the minimum occupation probability when the reader collision occurs. Then we analyze the performance of the proposed algorithm using simulation tool.

• The KIPS Transactions:PartA
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• v.16A no.4
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• pp.289-298
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• 2009

Generally, RFID systems are composed of one reader and several passive tags, and share the single wireless channel. For this reason, collisions occurwhen more than two tags simultaneously respond to the reader's inquiry. To achieve this problem, many papers, such as QT[8], HCT[10], BSCTTA[2], and QT-BCS[9], have been proposed. In this paper, we propose the tree-based anti-collision algorithm using a bit change sensing unit (TABCS) based on BSCTTA algorithm. The proposed algorithm can identify bits returned from tags through bit change sensing unit, even if multi collisions occur. So, it rapidly generates the unique prefix to indentify each tag, and reduce the total of bits. As the result, the cost of identifying all tag IDs is relatively reduced as compared with existing algorithms. It is verified through simulations that the proposed algorithm surpass other existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1130-1137
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• 2006

One of the important performance issues in large-scale RFID systems is to resolve collisions among responses from RFID tags. Considering two do facto anti-collision solutions, namely the binary-tree splitting algorithm and the Slotted-Aloha algorithm, we propose to use multi-packet reception (MPR) capability to enhance the RFID tag reading rate (i.e., throughput). MPR allows an RFID reader to receive multiple reponses transmitted by tags at the same time. We analyze the effect of MPR capability in the above anti-collision algorithms, which is also validated by simulation. The analysis and simulation results show that RFID reader antenna design and signal separation techniques play an important role in improving RFID system performance with MPR capability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1155-1162
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• 2012

The purpose of this study is to investigate the effects of the bead shape on the crash performance of an aluminum crash box under a low-velocity impact condition. The initial peak load and impact energy absorption of a crash box with three types of bead shapes-edge concave, surface convex, and surface concave type-were studied through an FE analysis and an experiment. In addition, the effects of the bead shapes on the crash performance of the crash box were verified through a low-velocity-impact test with a front side member assembled with an aluminum crash box. The initial peak load of the surface-concave-type crash box was reduced by the bead, and therefore, deformation of the front side member at initial contact could be prevented. Furthermore, there was no deformation of the front side member after the impact test because the crash box with a surface-concave-type bead absorbed all the impact energy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.756-765
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• 2004

Using single carrier frequency RFID system in one-to-multiple wireless communications, might be generated data loss because of data collisions. Conventional Anti-collision method prevent data loss from data collisions which are binary tree method and ALOHA. However, those two preventive measures also have week points which are strongly dependent on the time and space when passing through the recognition area. This paper suggests the full-length instruction code method which fits in to half-duplex method, prevents data collision effectively by calculating the non-transmitting time of multiple tags considering approaching time to the recognition area. After full-length instruction code method test using 13.56MHz bandwidth RFID system shows that full-length instruction code method could make better result than any other methods. Moreover, the record shows O(n) result after analyzing O-notation of conventional time-domain procedure.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.185-186
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• 2014

전자해도 및 레이더와 같은 첨단운항시스템이 도입되고 있으나, 선박간의 충돌사고는 줄어들고 있지 않고 있으며 전체 사고의 30%를 차지하는 선박충돌사고의 80% 이상이 운항자의 실수에 의해 발생되고 있어, 이를 방지할 수 있는 지능적인 운항지원 시스템이 필요하다. 이를 위하여, 본 연구에서는 선박 충돌위험도 식별 정보를 활용하여 운항자에게 안전운항정보를 지원할 수 있는 시스템을 개발하였다. 기존에 항해레이더에서는 운항자가 특정 선박을 지정하여야만 선박충돌여유거리 및 선박충돌여유시간 등의 충돌예방정보를 얻을 수 있으나, 신규로 개발된 시스템에서는 선박들 중에 충돌위험이 높은 선박들을 자동으로 식별하여 충돌예상선박들의 정보를 실시간으로 제공받을 수 있어, 충돌 전에 미리 사고를 예방하고 신속히 대처할 수 있다. 개발된 시스템은 선박에 탑재하여, 실해역 성능시험을 실시하였다. 본 논문에서는 선박 충돌 위험도 기반의 안전운항 지원 시스템의 특징과 실해역 시험결과에 대해 소개한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.365-372
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• 2007

The function of navigational aids are to be coincided with the development of navigational equipment and increase of traffics on the sea fairway. Supplementary function or side effect of wharf-edge illumination would be effective to indicate fairway indirectly and collision avoidance between ships and bridge against background light in port area at night also a serious-view light on the bridge posts would be effective to ensure the drifting ships by wind and current force adjacent bridge area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.63-65
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• 2011

부산신항은 지형적인 특성상 마산 방면에서 입출항하는 선박과 신항으로 입출항하는 선박이 서로 교차하는 경우가 빈번하고 대형 컨테이너선과 저속 예부선 등의 통항량이 많을 뿐만 아니라 년 중 안개일수도 많아 충돌사고 위험이 상존한다. 따라서 선박에 정보제공 정도만 하는 소극적 관제 보다는 선박의 이동에 개입하는 적극적인 관제가 사고 방지에 더욱 효과적이라 할 수 있다. 부산신항의 관제 자료 및 해양안전심판원의 재결사례 등을 통하여 충돌사고의 원인을 분석하는 과정에서 적극적 관제의 필요성을 확인할 수 있었다. 본고에서는 부산신항에서의 적극적 관제 사례와 문제점을 주로 법률적인 측면에서 살펴보고, 적극적 관제의 개선 방안을 도출하여 보았다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.243-244
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• 2010

본 논문에서는 대구경북과학기술연구원에서 개발한 77GHz FMCW ((Frequency Modulation Continuous Wave) 충돌방지 레이더 테스트 시스템에 대하여 소개한다. FMCW 레이더 개발에 적용된 기능 및 구현에 대하여 소개한다. 개발된 시스템은 RTS (Radar Test System)과 연동하여 성능을 검증하고, 차량에 장착하여 실제 주행시험을 실시하였다. 개발된 시스템은 150m의 거리까지 검출이 가능하며, 1024~8192point FFT를 적용하여 1km/h, 0.5m의 속도 및 거리 분해능을 제시하고 있다.