• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2282-2288
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• 1998

ATM techniques ar ewidely accepted as a key transport mechanism infiber-based broadband network. However, to keep pace with the rpid emerging wireless high speed market, it is desirable to verify the reliability & daptability of ATM protocol on high error environment. This paper investigates the various ATM cell transfer characteristics over air interface. Though simulation, we analyze their usabilities of HeC mechanism and single-bit error correction algorithm based on ITU-T recommendation. We propose some methods for cell transport improvement over errored environment and investigate their performance for suggested schemes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.539-541
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• 2005

인터넷 서비스 보급이 대중화됨에 따라 인터넷을 이용한 다양한 부가 서비스들이 창출되고 있다. 대부분의 인터넷 사용자들은 항상 누군가로부터의 관심을 갈구하기 마련이다. 메신저의 대화명이나, 미니 홈피 등을 통해 수시로 자신의 현재 심리상태를 표현하는것은 그 좋은 예라 할수 있다. 향후, 개발될 새로운 부가서비스는 이러한 사용자들의 현재 상태를 표현하기 위한 프레즌스 서비스와 통합된 형태로 발전해 나갈것으로 여겨진다. 본고에서는 현재 IETF를 중삼으로 진행되고 있는 SIP 기반 프레즌스 및 인스턴스 메시징 서비스에 대한 소개와, 사용자의 프레즌스 정보를 다양하게 기술하기 위한 프레즌스 고급 기능 표준기술도 함께 소개하고자 한다.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.115-121
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• 2015

In order to assess the water quality of Kumho river using Diatom Assemblage Index to organic water pollution (DAIpo) and to campare from the previous water quality, 5 sites in Kumho river were selected and assessed total of 6 times, every April and September from April 2010 to September 2012. As a result, 116 taxa were found in 2 Order, 3 Suborder, 7 Families, 26 Genera, 103 species and 13 varieties. Saprophilous species of 10 dominant species including Achnanthes minutissima, were increased as going to downstream sites. Correlation coefficients (r) between epilithic diatom communities and physicochemical factors were from - 0.62 to 0.71. Correlation coefficients (r) between TN and diatom indices (DAIpo, TDI) were 0.57 and 0.65, respectively. Therefore, epilithic diatom communities were greatly influenced by TN. The Correlation between DAIpo and TDI measured to be high in correlation coefficient (r=0.62) from the result of correlation analysis. Mean of DAIpo values ranged between 37.24~74.98 and decreased as going to downstream sites. Saprobic level was estimated as ${\beta}$-oligosaprobic at st. 1, ${\alpha}$-oligosaprobic at st. 2 and ${\beta}$-mesosaprobic at st. 3. But st. 4 and 5 which were ${\alpha}$-mesosaprobic and polysaprobic in the previous results, were improved as ${\beta}$-mesosaprobic. The RPId, general assessment of the water quality using DAIpo, was 52.27, which means the water quality of Kumho river was middle level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2465-2472
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• 2009

This research paper is to develop remote data transmission terminal which is adequate to RFID R/W by using UHF/RF RFID R/W module (WJR7090) and Bluetooth communication(FB755AC) with ARM chipset(AT91SAM7S256). The developed UHF RFID R/W terminal performs tagging of RPID value and transmit the value to server with Bluetooth communication, the transmitted RFID tag value is compared to the Database value and the result is transmitted to the terminal. Performance test was done in order to prove the performance of the terminal, and the test result of the terminal's excellency and transmitted/recevied packet is described.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.483-492
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• 2007

In this paper, we propose a new hybrid approach based on query tree protocol to arbitrate tag collisions in RFID systems. The hybrid query tree protocol that combines a tree based query protocol with a slotted backoff mechanism. The proposed protocol decreases the average identification delay by reducing collisions and idle time. To reduce collisions, we use a 4-ary query tree instead of a binary query tree. To reduce idle time, we introduce a slotted backoff mechanism to reduce the number of unnecessary Query commands. Simulation and numerical analysis reveal that the proposed protocol achieves lower identification delay than existing tag collision arbitration protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.805-811
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• 2009

Firstly, this dissertation suggests the tag ID transfer method using two-dimensional arrangement. Secondly, provide better and stable security system compare to existing one by transferring tag; ID using established two-dimensional arrangement. Thirdly, provide operating module, which possible to descramble two-dimensional arrangement, with a character set when descrambling in a tag and a server. Lastly, suggest safe key transfer using a character set and two-dimensional arrangement. In order to embody suggested system and assess, transferred two-dimensional arrangement several times to carry out the experiment. Confirmed that it is impossible for suggested system to decode key patterns compare to existing RFID systems.

• Journal of The Korean Association of Information Education
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• v.18 no.2
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• pp.325-334
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• 2014

There are management and price problems that have been caused by requirement of RFID reader, Fingerprint Identification System and Clicker for the construct of automatic attendance system to check the students' attendance accurately and quickly. Therefore, in the thesis, we developed smartphone based attendance check system by utilizing Wi-Fi and the smartphones that has been already built without using additional equipments and establishing construction of system additionally. It recognizes date, time, location and the seat number in classroom if a student logs the attendance chocking application in and it also allows students to get lecture feedback and check attendance by taking quizzes and questionnaires that are related to the lecture. As a result, by applying the attendance check system, instructors state that it is convenient since the app allows instructors to communicate with students though the quizzes and questionnaires. Especially, the instructors state that it is convenient because the results of the quizzes, questionnaires and attendance can be downloaded it the from of Excel files.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.986-995
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• 2011

Recently, the market of fiber and apparel industry is rapidly changing from producer to consumer oriented. This trend emphasizes the necessity of SCM systems being able to do flexible correspondences to the market changing through synthetically reflecting consumers' various needs and a variety of patterns. However, because traditional SCMs manage their supply chains being based on bar code systems from the production to the distribution, they are suffering from the needs of real time information sharing and have their essential restrictions in the response to the environmental changes of the market and consumers' needs. This paper suggests a new RFID based u-SCM system optimized into the fiber and apparel industry. The proposed system has the benefits that through basing on RPID can collect information of the production and the distribution real time and make better use of it and connect to the legacy systems organically via Web services and rapidly respond to the market changing and consumers' needs. Through implementation, it is demonstrated that the proposed system can effectively facilitate them.

• Journal of Intelligence and Information Systems
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• v.11 no.2
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• pp.105-121
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• 2005

To realize a ubiquitous logistics management system using the smart object of Electronic Product Code(EPC) enabled RFID tag, the design and management of RFID Information Service is very important. RFID Information Service searches, transfers and responds to the other's PML request, but Physical Markup Language (PML) data management between trading system elements has issues of standardization of PML data description and processing, and problems of data traffic and communication time overload because of the innate distributed characteristics. As a complementary study, this research analyzes the usage patterns and data types of PML. On that analysis we provide a design of the distributed RFID Information Service architecture of PML data management that is using DB middleware. Standalone and Integrated type of RFID IS were proposed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.5
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• pp.99-109
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• 2007

Lee et al. recently proposed an RFID mutual authentication scheme based on synchronized secret information. However, we found that their protocol is vulnerable to a spoofing attack in which an adversary can impersonate a legal tag to the reader by sending a malicious random number. To remedy this vulnerability, we propose two RFID authentication protocols which are secure against all possible threats including backward and forward traceability. Furthermore, one of the two proposed protocols requires only three hash operations(but, $[m/2]{\cdot}2+3$ operations in resynchronization state, m is the number of tags) in the database to authenticate a tag, hence it is well suitable fur large scale RFID systems.