• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.5
• /
• pp.12-20
• /
• 2008

RFID(Radio frequency indentification) technology, that the reader detect the tag information attached on the objects without contact, is considered the kernel of realizing tile Ubiquitous Sensor Network. Particularly, because there are lots of tags(which the reader have to detect) in the UHF RFID system(that is applied at the Logistic & Distribution industry). In the UHF RFID system the negative effects, we called the tag-collision, may occur and we should solve these effects. So, in the EPCglobal Gen2 protocol they present the Slotted Random Anti-collision algorithm to prevent the tag-collision effect. In this paper, in order to minimize the tag-collision effect and bring on the system efficiency, we propose the Power Increasing Method that controls the transmission power of the reader depending on the environment and verily the improved performance.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.10
• /
• pp.1887-1894
• /
• 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.

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

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.6
• /
• pp.999-1005
• /
• 2008

RFID(Radio Frequency IDintification) leader is collision of data, when recognizing the multiple tag the inside area. This collision became the cause which delays the tag recognition time of the leader. The protocol which prevents the delay of tag recognition time of the leader the place where representative it uses QT(Query Tree) algorithms, it uses a collision bit position from this paper and are improved QT-MTC(Query Tree with Multi-Tag Cognition) algorithms which it proposes. This algorithm stored the bit position which bit possibility and the collision where the collision happens occurs in the stack and goes round a tree the number of time which, it reduced could be identified two tags simultaneously in order, it was planned. A result of performance analysis, It compared in QT protocols and the this algorithm against the tag bit which is continued a high efficiency improvement effect was visible.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.22 no.3
• /
• pp.405-415
• /
• 2012

In many applications a reader needs to determine whether a particular tag exists within a group of tags without a server. This is referred to as serverless RFID tag searching. A few protocols for the serverless RFID searching are proposed but they are the single tag search protocol which can search a tag at one time. In this paper, we propose a multi-tag search protocol based on a hash function and a random number generator which can search some tags at one time. For this study, we introduce a protocol which can resolve the problem of synchronization of seeds when communication error occurs in the S3PR protocol[1], and propose a multi-tag search protocol which can reduce the communication overhead. The proposed protocol is secure against tracking attack, impersonation attack, replay attack and denial-of-service attack. This study will be the basis of research for multi-tag serach protocol.

• Journal of the Korea Safety Management & Science
• /
• v.10 no.2
• /
• pp.155-162
• /
• 2008

The ubiquitous, which is developed for human's convenience, uses the concept of situation awareness that communicates with computer and performs a certain work without user's recognition. In order to collect the information of situation, many devices are required. Also, in the condition of ubiquitous middleware, priority is given to effective controls of various devices. There are many devices for collecting the information of situation awareness such as sensor, RFID, etc. Among them, in the use of RFID, the researcher performed the experiment, in which multiple readers were used depending on the necessity of awareness information, and found the problem of intervention between readers occurring when multiple readers are used. The paper handles the problem of intervention causing from using multiple readers and suggests middleware design module using session manager to solve the problem.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.06d
• /
• pp.91-93
• /
• 2006

RFID(Radio Frequency IDentification) 기술은 RF 신호를 사용하여 물품에 부착된 전자 태그(tag)를 식별하는 비접촉자동인식 기술이다. 이런 RFID 기술의 확산을 위해서는 리더가 다수의 태그를 빠른 시간 안에 인식하는 다중 태그 식별 문제를 해결 해야만 한다. 지금까지 이 문제를 해결하기 위한 충돌 방지(anti-collision) 알고리즘이 많이 개발되었다. 본 논문에서는 이런 충돌 방지 알고리즘 중에서 18000-6 Type A, Type B와 Type C로 새롭게 채택된 EPCglobal Class1 Generation2, 그리고 Query Tree Protocol에 대한 시뮬레이션 시스템의 구조를 소개하고 실제 시뮬레이션 했을 때의 각 알고리즘에 대한 간단한 성능 평가를 한다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.2
• /
• pp.308-313
• /
• 2018

In this paper, we propose a sampled-data model predictive tracking control deign for leader-following control of multi-mobile robot system. The error dynamics of leader-following robots is modeled as a Linear Parameter Varying (LPV) model. Also, the Lyapunov function is presented to guarantee stability of the networked control system. Based on the stabilization condition using a quadratic Lyapunov function approach, model predictive sampled-data controller is designed. Finally, the leader-following control of multi mobile robots is simulated to show effectiveness of the proposed method.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2007.05a
• /
• pp.795-798
• /
• 2007

RFID 리더기가 영역내의 다수의 태그를 인식하기 위해선 충돌방지 알고리즘이 필수적으로 요구된다. 본 논문은 Auto ID Class 0에서 정의한 충돌방지 알고리즘인 Bit-by-Bit 이진트리 알고리즘(BBB)의 충돌 위치를 스택에 저장하고 이를 통해 다음 질의어를 결정함으로써 성능이 크게 개선된 Stack-bit-by-bit(SBBB) 알고리즘을 제안한다. 시뮬레이션을 통한 검증결과 질의-응답 횟수, 질의어의 크기, 응답어의 크기의 모든 면에서 성능이 개선된 것을 확인할 수 있었다.

• Proceedings of the Korea Contents Association Conference
• /
• 2017.05a
• /
• pp.83-84
• /
• 2017

본 연구는 직무자원과 직무요구, LMX가 노인복지관의 사회복지사들의 소진에 미치는 영향을 실증적으로 검증하였다. 본 연구는 경기도 지역의 50개 노인복지관을 대상으로 총 315부의 설문조사를 실시하였다. 조사는 우편으로 진행하였고, 회수된 설문지는 총 33개 기관 189부이다. 조사기간은 2016년 1월-2월 약 두달간 이루어졌고, 기술통계, 다중회귀분석방법으로 분석하였다. 분석결과 직무자원과 직무요구는 소진에 영향을 나타내어, 직무자원이 많을수록 사회복지사들의 소진이 감소되며, 직무요구가 높을수록 사회복지사들의 소진도 높다고 할 수 있다. 또한 LMX는 직무자원, 직무요구와 소진과의 관계를 부분 매개하는 것으로 검증되었다. 이러한 결과를 토대로 노인복지관 사회복지사들의 소진을 감소하기 위하여 조직관리와 인적자원관리에 대한 함의를 찾을 수 있다.