• 제목/요약/키워드: Anti-collision system

검색결과 157건 처리시간 0.024초

Enhanced bit-by-bit binary tree Algorithm in Ubiquitous ID System (Ubiquitous ID 시스템에서의 Enhanced bit-by-bit 이진 트리 알고리즘)

  • 최호승;김재현
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • 제41권8호
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    • pp.55-62
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    • 2004
  • This paper proposes and analyzes two anti-collision algorithms in Ubiquitous ID system. We mathematically compares the performance of the proposed algorithms with that of binary search algorithm slotted binary tree algorithm using time slot, and bit-by-bit binary tree algorithm proposed by Auto-ID center. We also validated analytic results using OPNET simulation. Based on analytic result comparing the proposed Modified bit-by-bit binary tree algorithm with bit-by-bit binary tree algorithm which is the best of existing algorithms, the performance of Modified bit-by-bit binary tree algorithm is about 5% higher when the number of tags is 20, and 100% higher when the number of tags is 200. Furthermore, the performance of proposed Enhanced bit-by-bit binary tree algorithm is about 335% and 145% higher than Modified bit-by-bit binary tree algorithm for 20 and 200 tags respectively.

A Study on Development ATCS of Transfer Crane using Neural Network Predictive Control (신경회로망 예측제어에 의한 Transfer Crane의 ATCS개발에 관한 연구)

  • Sohn, Dong-Seop;Lee, Jin-Woo;Lee, Young-Jin;Lee, Kwon-Soon
    • Journal of Navigation and Port Research
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    • 제26권5호
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    • pp.537-542
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    • 2002
  • Recently, an automatic crane control system is required with high speed and rapid transportation. Therefore, when container is transferred from th intial coordinate to the finial coordinate, the container paths should be built in terms of the least time and no swing. So in this paper, we calculated the anti-collision path for avoiding collision in its movement to the finial coordinate. And we constructed the neural network predictive PID (NNPPID) controller to control the precise navigation. The proposed predictive control system is composed of the neural network predictor, PID controller, neural network self-tuner which yields parameters of PID. Analyzed crane system through simulation, and proved excellency of control performance than other conventional controllers.

A Study on Design of Controller for ATC using Neural Network Predictive Control (신경회로망 예측제어를 이용한 ATC 제어기 설계에 관한 연구)

  • Sohn, Dong-Seop;Lee, Jin-Woo;Lee, Jin-Young;Lee, Jang-Myung;Lee, Kwon-Soon
    • Proceedings of the KIEE Conference
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    • 대한전기학회 2003년도 하계학술대회 논문집 D
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    • pp.2456-2458
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    • 2003
  • Recently, an automatic crane control system is required with high speed and rapid transportation. Therefore, when container is transferred from the initial coordinate to the finial coordinate, the container paths should be built in terms of the least time and without sway. Therefore, we calculated the anti-collision path for avoiding collision in its movement to the finial coordinate in this paper. And we constructed the neural network predictive two degree of freedom PID (NNPPID) controller to control the precise navigation. The proposed Predictive control system is composed of the neural network predictor, two degree of freedom PID(TDOFPID) controller, neural network self-tuner which yields parameters of TDOFPID. We analyzed crane system through simulation, and proved excellency of control performance over the conventional controllers.

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Improved variable bits M-ary QT conflict resolution algorithm for discrete m-bits recognition in RFID system (RFID 시스템에서 불연속 m-bits 인식을 위한 개선된 가변비트 M-ary QT 충돌해소 알고리즘)

  • Kim, Kwan-woong;Kim, Byun-gon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제20권10호
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    • pp.1887-1894
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    • 2016
  • In the RFID system, the reader transmits a query message to tags in order to identify a unique ID of tags within its detection range. The procedures for arbitrating a collision is essential because the multiple tags can response simultaneously in the same to the query of the Reader. This procedure is known as conflict resolution algorithm and it is a key technology in the RFID system. In this paper, we proposed a variable bits M-ary QT algorithm based on Manchester coding techniques. The proposed algorithm use the location information of the collision bits in the reader and tags. The proposed algorithm can reduce the number of the query-response cycle because it is capable of recognizing discontinuous bits and a variable number of bits. From computer simulation, the proposed method give better performance than the conventional M-ary QT techniques in terms of response, recognition efficiency, communication overhead.

Laser Tracking Analysis of Space Debris using SOLT System at Mt. Gamak (감악산 SOLT 시스템을 이용한 우주잔해물 레이저추적 성능분석)

  • Lim, Hyung-Chul;Park, Jong-Uk;Kim, Dong-Jin;Seong, Kipyung;Ka, Neung-Hyun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • 제43권9호
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    • pp.830-837
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    • 2015
  • Space debris has been a major issue recently for the space-active nations because its growing population is expected to increase the collision risk with operational satellites. Radar and electro-optical system has been used for space debris surveillance, which may cause unnecessary anti-collision manoeuvers due to their low tracking accuracy. So an additional tracking system is required to improve the predicted orbit accuracy and then to jude the anti-collision maneouvers more efficiently. The laser tracking system has been considered as an alternative to decrease these unnecessary manoeuvers. Korea Astronomy and Space Science Institute has been developing a space object laser tracking system which is capable of laser tracking for satellites with retro-reflectors and for space debris using high power laser, and satellite imaging using adaptive optics. In this study, the tracking capability is analyzed for space debris using high power laser based on link budget, false alarm probability and signal detection probability.

Dynamics Analysis and experiment verification of seatbelt system with pre-tensioner considering connection action of a human body (인체의 연계작용을 고려한 프리텐셔너를 가진 시트벨트 시스템의 동역학 해석 및 실험적 검증)

  • Kuk, Min-Gu;Tak, Tea-Oh;Park, Jae-Soon;Kim, Dae-Hee
    • Proceedings of the KSME Conference
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1009-1014
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    • 2007
  • To improve passenger safety, seatbelt systems with pre-tensioner that tightens seatbelt webbing using explosives just before collision are widely adopted. Even though seatbelt must not be unlatched without passenger's operation, release of a buckle due to explosion of pre-tensioner takes place in some situations resulting in serious injury to passengers. To prevent the unintended unlocking, a pendulum like part called anti-g mass is attached to the buckle to block displacement of release button. In this study, the unlocking conditions of anti-g buckle when pre-tensioner explodes has been theoretically investigated. Through multibody model of the seatbelt system incorporating every detailed part of the buckle, dynamic analysis of the seatbelt system with pre-tensioner has been performed including the driver's body model that interacts with seatbelt system. The simulations results has been validated through actual sled test with driver dummy and the seatbelt system.

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Performance Improvement of Anti-collision Algorithm for RFID Protocol and Algorithm Comparison (RFID 프로토콜의 충돌방지 알고리즘의 성능 개선과 알고리즘 비교)

  • Lim, Jung-Hyun;Kim, Ji-Yoon;Jwa, Jeong-Woo;Yang, Doo-Yeong
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • 제44권6호
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    • pp.51-61
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    • 2007
  • In this paper, Air-interface protocols of ISO 18000-6 Types and EPCglobal Classes applied to RFID system in UHF band are analyzed, and those anticollision algorithms are realized. Also, the each algorithm which improves the performance of standard protocol is proposed, and the performance is compared when clock period of link timing is a identical condition on $12.5{\mu}s$. As the result, when 500 tags exist simultaneously inside reader interrogation zone, the tag recognition performance of a standard protocol is better in preceding order of Class-1 Generation-1, Type B, Type A, Class-0 and Class-1 Generation-2. And also the performance of improved protocol is better in ascending order of Type B, Type A, Class-1 Generation-1, Class-0 and Class-1 Generation-2. Therefore, performance of tag recognition remarkably depends on the regulated clock period in the protocol and link timing between a reader and a tag.

A Hybrid Hyper Query Tree Algorithm for RFID System (RFID 시스템을 위한 하이브리드 하이퍼 쿼리 트리 알고리즘)

  • Kim, Tae-Hee;Lee, Seong-Joon;Ahn, Kwang-Seon
    • The KIPS Transactions:PartA
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    • 제15A권5호
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    • pp.287-294
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    • 2008
  • A tag collision arbitration algorithm for RFID passive tags is one of the important issues for fast tag identification, since reader and tag have a shared wireless channel in RFID system. This paper suggests Hyper-Hybrid Query Tree algorithm to prevent the tag-collisions. The suggested algorithms determine the specified point in time for tag to transfer ID to reader by using value 1 of the upper 3 bit based on Query Tree. Also, because the transferred upper 3 bits of tag is different depending on the time of transfer, it is possible to predict in the suggested Algorithm. In the performance evaluation through simulation, it shows the suggested algorithm has higher performance in the number of queries compared to other Tree-based protocols.

Adaptive RFID anti-collision scheme using collision information and m-bit identification (충돌 정보와 m-bit인식을 이용한 적응형 RFID 충돌 방지 기법)

  • Lee, Je-Yul;Shin, Jongmin;Yang, Dongmin
    • Journal of Internet Computing and Services
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    • 제14권5호
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    • pp.1-10
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    • 2013
  • RFID(Radio Frequency Identification) system is non-contact identification technology. A basic RFID system consists of a reader, and a set of tags. RFID tags can be divided into active and passive tags. Active tags with power source allows their own operation execution and passive tags are small and low-cost. So passive tags are more suitable for distribution industry than active tags. A reader processes the information receiving from tags. RFID system achieves a fast identification of multiple tags using radio frequency. RFID systems has been applied into a variety of fields such as distribution, logistics, transportation, inventory management, access control, finance and etc. To encourage the introduction of RFID systems, several problems (price, size, power consumption, security) should be resolved. In this paper, we proposed an algorithm to significantly alleviate the collision problem caused by simultaneous responses of multiple tags. In the RFID systems, in anti-collision schemes, there are three methods: probabilistic, deterministic, and hybrid. In this paper, we introduce ALOHA-based protocol as a probabilistic method, and Tree-based protocol as a deterministic one. In Aloha-based protocols, time is divided into multiple slots. Tags randomly select their own IDs and transmit it. But Aloha-based protocol cannot guarantee that all tags are identified because they are probabilistic methods. In contrast, Tree-based protocols guarantee that a reader identifies all tags within the transmission range of the reader. In Tree-based protocols, a reader sends a query, and tags respond it with their own IDs. When a reader sends a query and two or more tags respond, a collision occurs. Then the reader makes and sends a new query. Frequent collisions make the identification performance degrade. Therefore, to identify tags quickly, it is necessary to reduce collisions efficiently. Each RFID tag has an ID of 96bit EPC(Electronic Product Code). The tags in a company or manufacturer have similar tag IDs with the same prefix. Unnecessary collisions occur while identifying multiple tags using Query Tree protocol. It results in growth of query-responses and idle time, which the identification time significantly increases. To solve this problem, Collision Tree protocol and M-ary Query Tree protocol have been proposed. However, in Collision Tree protocol and Query Tree protocol, only one bit is identified during one query-response. And, when similar tag IDs exist, M-ary Query Tree Protocol generates unnecessary query-responses. In this paper, we propose Adaptive M-ary Query Tree protocol that improves the identification performance using m-bit recognition, collision information of tag IDs, and prediction technique. We compare our proposed scheme with other Tree-based protocols under the same conditions. We show that our proposed scheme outperforms others in terms of identification time and identification efficiency.