• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.202-207
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• 2013

RFID technology is applied to port logistics applications since it monitors objects wirelessly without line of sight and constructs ubiquitous system with low cost. Changes of stock status in the warehouse environment make the technology more important for managing such frequent storing and un-storing. Although the RFID has beneficial characteristics of low cost and low complexity, simultaneous responses of RFID tags cause tag identification collision due to absence of elaborate medium access control scheme. Several algorithms have been proposed to overcome the tag collision problem. However, it is difficult to adopt the methods to the logistics systems that has varying loads since there was no consideration on RFID tag's mobility. Therefore, we propose an efficient RFID tag anti-collision protocol, and simulation results demonstrate performance improvement by using the proposed scheme.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.132-140
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• 2010

RFID-based games, which use a RFID reader and RFID chips, will expand existing computer games, which use a computer screen, a keyboard or a mouse. This paper presents 4 RFID digital board game contents which are conducted by initial developers; the three of them use the screen and control the games with RFID chips and, one is a different attempted game which can exclude the screen and be immersed to the board. While initial developers use object recognition of RFID, we need to develop game contents and game interface which can recognize positions of the objects. According to the initial developer"s developing process, the cooperative system between the game technical developers and the contents developers should be necessary. Also, the interface should be developed for young children to participate and operate.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.423-432
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• 2011

In a warehouse, because there exist frequent changes of stock status and the quality of some contents are influenced by the environment such as temperature, fast and accurate management of the warehouse's environment is very important for Warehouse Management Systems (WMS). However, due to the absence of a unified standard for the communication protocol between RFID nodes, the connection between RFID nodes can be broken in case of movement of a RFID reader to a region with a different protocol. Moreover, centralized MAC schemes for RFID communications in previous studies have severe problems. For an example, if a cluster header disappears from the cluster due to the cluster header's movement or bad channel conditions, the RFID member nodes of the cluster waste lots of time and energy to re-elect a new cluster header. Therefore, in this paper, we propose a WiMedia Distributed MAC (D-MAC) scheme for RFID communications and its cooperative relay transmission scheme for WMS applications Simulation results show performance improvement at the RFID node by using the proposed cooperative relay transmission scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.100-102
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• 2005

유비쿼터스는 현재의 제한된 컴퓨팅 환경을 떠나서 시간과 장소에 구애받지 않는 자유로운 컴퓨팅 환경을 제공함으로서 각광받고 있다. 그 중 언제어디서나 정보를 주고받을 수 있으며 가격과 성능 면에서 단연 뛰어난 RFID(Radio Frequency Identification)의 중요성은 점점 증가되고 있는 추세이다. 그러나, 이와 같은 우수성에도 불구하고, 정보 유출의 위험성을 내포하고 있으며, 개인의 위치 추적이나, 비 접근 권한자의 위장행세 등의 사용자 프라이버시 보호에 대한 많은 문제점들을 수반한다. 현재까지 이와 관련된 연구들이 활발히 진행되고 있다. 특히 그 중, Ohkubo의 해시함수를 이용한 프로토콜은 프라이버시 보호 측면에서 위치추적 공격(location tracking), 전방위보안성(forward security)과 같은 문제들에 대한 해결책을 제시하고 있으나, 해시함수를 태그에 직접 구현하는 것은 현재까지는 불가능한 상태이다. 또한, Martin Feldhofer는 대칭키 암호 알고리즘인 AES(Advanced Encryption Standard)를 태그에 구현을 함으로서 암호학적인 강도를 높였으나, 위치추적 공격에 대한 문제정과 물리적 공격에 대한 가정을 하지 않은 단점을 가지고 있다. 본 논문에서는 기존연구에서의 문제점들을 보완하고자 현실적으로 구현 가능한 AES를 사용하고, 위치추적 공격, 비권한자 접근(unauthorized access) 공격과 물리적 공격으로부터 안전하며 전방위보안성을 제공하는 기법을 제안한다.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.507-514
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• 2006

Various application systems are developed using RFID as a part of ubiquitous computing, and it is expected that RFID chip will become wide-spread for the distribution industry especially. Efficient and efact intelligent-type of warehouse management system is essential for small-to-medium-sized enterprises in the situation having a trouble in the viewpoint of expense and manpower. In this paper, we implement small-scale warehouse management system using log-based context awareness technology. This system is implemented to be controlled on web, configuring clients to control RFID readers and building up DBMS system in a server. Especially, it grasps user's intention of storing or delivering based on toE data for the history of user's access to the system and it reports user's irregular pattern of warehouse use and serves predictive information of the control of goods in stock. As a result, the proposed system can contribute to enhance efficiency and correctness of small-scale warehouse management.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.221-226
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• 2010

Ubiquitous computing is technology that provides services appropriate for the user. At places where environmental and situational context are relevant in making the determination of what services are appropriate, there are sensor nodes installed, which automatically collect, manage and control environmental information. In this computing environment, in order to meet the requirements of services provided to users, a context awareness system is needed for context awareness processing. In this thesis, using RFID/USN sensors, the context of a user entering and leaving an area was produced, and the user's identification information was received via the RFID reader and antenna. At the same time, to decide whether or not to allow access for the user, a distance sensor node was installed to collect context data. Based on this, a system that provides practical services needed in real life for users was designed and implemented. The context of a user entering an area was produced, which the system recognized and provided appropriate services for the user.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.4
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• pp.53-63
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• 2008

Reader collision may occur when neighboring RFID readers use the same channel at the same time. Especially when the readers are operated in dense mode, even though many channels are available, because of frequent reader collisions we can not guarantee the performance of RFID readers. Conventional solutions such as FH(Frequency Hopping) or LBT(Listen Before Talk) are not effective in this situation because they can not schedule RFID readers effectively when RFID readers are operated in multi-channel, dense reader mode, In this paper, we propose a new RFID reader anti-collision algorithm which employs LBT, random backoff before channel access, and probabilistic channel hopping at the same time. While LBT and Random backoff before channel access reduces collisions between competing readers, probabilistic channel hopping increases channel utilization by adaptively changing the hopping probability by reflecting the reader density and utilization. Simulation results shows that our algorithm outperforms conventional methods.

• 한국IT서비스학회:학술대회논문집
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• 2008.05a
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• pp.552-558
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• 2008

USN (Ubiquitous Sensor Network)의 인프라 기술은 유비쿼터스 환경에서의 다양한 서비스를 창출하고 실생활에 적용할 수 있는 기술로 정착하고 있다. 산업분야에서는 관계적 협업이 중시되는 비즈니스 환경에서 실시간 기업이 되기 위해 RFID, EPC 네트워크 등의 기술을 비즈니스 서비스 모델에 적용한 u-SCM으로 적용할 수 있다. 웹 서비스 환경에서 u-SCM을 적용하면서도 고차원의 공급사슬 통합이 이루어지기 위해서는, 여러 상호작용주체가 참여하는 글로벌 프로세스 수준에서 u-SCM프로세스를 관리하고 제어할 필요가 있으며, 본 논문에서는 유비쿼터스 컴퓨팅 기술을 SCM에 적용한 u-SCM 프로세스를, 비즈니스 프로세스 표준언어인 BPEL(Business Process Execution Language)을 적용하여, 각 업무프로세스를 웹서비스로 구성된 환경에서 효과적으로 통합하여 적용하도록 하는 방안을 제시한다. 이러한 접근법은 기업, 조직 간에 적재적소에 실시간 데이터를 수집하고 접근 및 분석하여, 업무 프로세스의 중단이 없도록 u-SCM 프로세스의 진행과정을 보다 효율적으로 관리, 모니터링 하는 것이 가능하도록 하며, 향후 u-SCM프로세스 수행 결과를 토대로 프로세스의 개선에 대한 방안을 모색할 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.539-544
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• 2020

The research is on progressing to operate digital door lock with the method to guarantee the security and safety in the meantime to use digital door lock conveniently using Internet of Things (IoT) standardizing various service providing technology using IoT in home network currently. In this study, compose home network interconnecting Raspberry-PI and web server reflection this trend and composed the system to control the door lock after connect Arduino substituting converter function. Making Raspberry-PI using dynamic IP address using existing open source easily maintain DNS information and possible to connect internet network in home network ethernet and finally, making the smartphone can control door lock remotely entering designated address after connect the internet. The connection between home network and Arduino is executed by Raspberry-PI and bluetooth pairing as 1:1 and make random user's access to be impossible. Especially, to make open/close the door lock with smartphone not by using password on the keypad or using RFID card is judged as the method increasing the security make random user's access to be impossible and also increased the usefulness making remote control to be possible.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1356-1363
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• 2004

We propose Tangible Media Control System (TMCS), which allows users to manipulate media contents with physical objects in an intuitive way. Currently, most people access digital media contents by exploiting GUI. However, It provides limited manipulations of the media contents. The proposed system, instead of mouse and keyboard, adopts two types of tangible objects, i.e RFID-enabled object and tracker-embedded object. The TMCS enables users to easily access and control digital media contents with the tangible objects. In addition, it supports an interactive media controller which users can synthesize media contents and generate new media contents according to users' taste. It also offers personalized contents, which is suitable for users' preferences, by exploiting context such as user's profile and situational information. Therefore. the proposed system can be applied to various interactive applications such as multimedia education, entertainment and multimedia editor.