• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.10-19
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• 2007

In this paper, Class-1 Air-interface protocols of EPCglobal applied to RFID system in UHF band are analyzed, and the standard anticollision algorithms are realized. Also, the improved anticollision algorithms of the Class-1 Generation-1 and Generation-2 protocol are proposed and the performances of anticollision algorithms are compared. As the results, reduction ratio of total tag recognition time of the improved Generation-1 algorithm is 54.5% for 100 tags and 63.4% for 1000 tags with respect to standard algorithm, respectively. And the reduction ratio of the improved Generation-2 algorithm is 7.9% for 100 tags and 11.7% for 1000 tags. Total recognition times of the improved algorithms are shorter than those of standard algorithms according to increasing the number of tag. Therefore, the improved anticollision algorithm proposed in this paper is the advanced method improving the performance of tag recognition in the RFID system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.953-955
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• 2014

최근 차량 충돌 방지를 위한 다양한 기술이 상용화되고 있다. FMCW 기반의 레이더 시스템은 구현의 용이성으로 많은 상용차에서 전면 충돌 방지 시스템에 적용되고 있다. 측면 충돌 방지를 위한 BSD(Blind Spot Detection)와 차선변경 보조 시스템(LCA, Lane Change Assistant system)에서는 전방 레이더보다 인식거리가 줄어들고 갱신율이 낮아지므로 고속 FFT 등을 수행하는 신호처리부를 저가격으로 설계가 가능할 것이다. 본 연구에서는 TI사의 MCU인 F28335를 사용하여 근거리를 인식하는 신호처리부를 설계하였다. 이 MCU는 16채널 12bit ADC와 68KB RAM 및 512KB 플래시 메모리를 내장하고, 150MHz 부동소수점 연산을 지원하여 단일 칩으로 신호처리부의 구현이 가능하다. 구현된 시스템은 20m내외의 거리에 있는 장애물에 대하여 10Hz로 갱신이 가능하여 BSD를 위한 기본 기능이 확인되었다. 이러한 구현은 이전의 고가의 DSP나 FPGA를 사용하지 않고 15$이내의 단일 MCU와 간단한 아날로그 회로로 설계되어 저가격의 시스템으로 상용화가 가능할 것이다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.11
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• pp.25-32
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• 2007

In this paper, we propose the Group Separation Algorithm for RFID Tag Anti-Collision. We study the RFID Tag anti-collision technique of ALOHA and the anti-collision algorithm of binary search. The existing technique is several problems; the transmitted data rate included of data, the recognition time and energy efficiency. For distinction of all tags, the Group Separation algorithm identify each Tag_ID bit#s sum of bit #1#. In other words, Group Separation algorithm had standard of selection by collision table, the algorithm can reduce unnecessary number of search even than the exisiting algorithm. The Group Separation algorithm had performance test that criterions were reader#s number of repetition and number of transmitted bits for understanding tag. We showed the good performance of Group Separation algorithm better than exisiting algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.177-183
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• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.30-33
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• 2006

RFID(Radio Frequency Identification)은 RF주파수를 이용해서 사물이나 사람의 정보를 인식하는 자동인식 기술이다. 이 기술은 무선 주파수를 사용해서 대량의 사물을 동시에 인식 할 수 있다는 장점이 있지만, 무선 주파수를 사용하기 때문에, 프라이버시 문제와 주파수 충돌문제와 같은 부수적인 단점을 가지고 있다. 리더 충돌문제를 해결하기 위한 여러 가지 많은 연구들이 진행 되고 있지만, 현재까지 연구된 대부분은 고정적인 환경에서의 해결 방법들이다. 본 논문에서는 앞으로 다가올 모바일 사회에 대비해서, 밀집된 모바일 환경에서의 리더 충돌 방지 기법을 제안한다. 이 기법은 모바일 리더의 위치를 계산하고, 적절한 주파수를 할당하고 동적으로 RF의 세기를 조절함으로써 리더의 충돌을 방지 한다.

• Annual Conference of KIPS
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• 2006.11a
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• pp.11-14
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• 2006

의견이나 이해가 서로 맞지 않는 경우 충돌은 발생한다. 유비쿼터스 컴퓨팅 환경에서 서비스를 수행하는 과정에서 발생하는 충돌의 경우 역시, 그 서비스의 요청 및 수행과정에서 발생하는 의견이해의 차이에서 비롯된다. 서비스의 수행을 결심하기 이전에 그 서비스에 연관된 의견이나 이해관계를 파악하고 그들 사이의 이견을 방지한다면, 서비스 사이에서 발생 가능한 대부분의 충돌을 방지할 수 있다. 본 논문에서는 이를 위해 유비쿼터스 컴퓨팅 환경에서 자동으로 서비스를 제공하는 시스템의 입장에서 각 서비스들이 환경과 그 환경 안의 자원들 사이의 관계에 대한 의미를 정의하고 결정함으로써, 다수의 서비스를 충돌 없이 수행할 수 있는 방법을 제안한다.

• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.338-347
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• 2024

This paper deals with the study of bird collision avoidance measures in UAM operations from an operator's perspective. Urban air traffic is defined as a next-generation transportation system that uses environmentally friendly electric vertical take-off and landing (eVTOL) aircraft to provide transportation services between key points within and around urban centers. For the successful establishment of the UAM industry, it is necessary to ensure safety issues that determine public acceptance. Among the hazards that can occur in aviation operations, preventing bird collisions in urban environments is a measure that can greatly secure operational safety and public acceptance. In addition to physical measures, procedural control measures are required to prevent bird strikes. In order to ensure the safety of UAM operations, this study aims to provide a direction for the establishment of UAM bird collision prevention measures by categorizing bird collision prevention measures into physical and procedural methods and flight sections such as takeoff, landing, and corridor sections. Through this, we hope to contribute to the improvement of the safety of the urban air traffic operation system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.330-336
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• 2020

An anti-collision system between equipment is essential on a drill floor where multiple moving machines are operated simultaneously. This is to prevent accidents by halting the machines when required, by inspecting possibility of a collision based on the relative position data sent by the equipment. In this paper, we propose a framework for an Anti-Collision System (ACS) by considering expandability of the number of machines and computational speed, to promote development of drilling machines and corresponding ACS software. Each drilling equipment is represented as an object in the software with its own message format, and the message is constructed with serialization/deserialization to manage any additional equipment or data. The data handling process receives the current status of machines from the drilling control network, and relays a collision related message (including bypass signal) back to the machines. A commercial visualization software shows the bounding boxes moving with the equipment and indicates probable collision. It has been determined that the proposed system maintains total execution time below 5ms to process data from the network and relay the information hence, the system has no effect on the machine control systems having 100ms control cycle.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.851-862
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• 2004

RFID(Radio frequency IDentification) is a technology that automatically identifies objects containing the electronic tags by using radio wave. The multi-tag identification problem is the core issue in the RFID and could be resolved by the anti-collision algorithm. However, most of the existing anti-collision algorithms have a problem of heavy implementation cost and low performance. In this paper. we propose a new tree based memoryless anti-collision algorithm called a collision tracking tree algorithm and presents its performance evaluation results obtained by simulation. The Collision Tracking Tree algorithm proves itself the capability of an identification rate of 749 tags per second and the performance evaluation results also show that the proposed algorithm outperforms the other two existing tree-based memoryless algorithms, i.e., the tree-walking algorithm and the query tree algorithm about 49 and 2.4 times respectively.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.85-94
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• 2008

When an RFID reader uses the same frequency or adjacent frequency with neighbor readers, the interference might occur. These interferences cause the RFID reader collision and errors during tag recognition. Therefore, the international standard for RFID and some papers proposed the methods to reduce the reader collision. The reader interference is closely related to the distance between the readers haying interference and used frequency band. In the previous RFID reader anti-collision algorithms, the location of readers inducing interference which is closely related to interference of readers is not considered. Only the reader collision is tried to reduce through frequency transfer after collisions occur or modification of frame size in relation to collision probability based a TDM(Time Division Multiplex). In this paper, the genetic algorithm using two-dimensional chromosome which reflect readers' location is proposed to prevent reader collision effectively. By executing evolutionary operation with two-dimensional chromosome, the location information having influence on reader interference can be used. The repair operation in the proposed algorithm makes all reader stably recognize their tags.