• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.85-90
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• 2006

RFID(Radio Frequency IDentification) is appearing by point technology by Ubiquitous environment of new paradigm and Logistics' application But, RFID chip of this is high price and short bandwidth, low power and interference etc. can become technological problem This is getting into obstacle in common use. Reader and tag, Embedded software etc.. that are accomplishing standardization are imported paying most expensive royalty. This paper deals with a RFID cognition system that use PDA under ubiquitous environment to apply to Logistics system A RFID cognition system processes input/output of fundamental information attaching a tag onto products. And a RFID cognition system supports quick, correct and sqfe synthetic Logistics managerial system through construction of database. This can minimize logistics costs and improve the quality of customer service. A RFID cognition system has advantage that can widen range of application to area that cognition system of existent fixing style can not do. Also, it can expect economical effect through inexpensive system construction.

• Journal of Korean Library and Information Science Society
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• v.36 no.4
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• pp.255-284
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• 2005

In this paper, we have made an analysis of dCollection license system and have presented the development subject based on various case study of digital rights Management( DRM ) under domestic and abroad Open Access circumstances. For this study, fist we made an investigation into the concept and the technical component of the copyright, license and DRM that act as obstacle to open access. It is hoped that the first study will be able to help people better understand the relationship between the related technique and Open Access System. Second we analyzed Creative Commons, RoMEO, Dspace system as abroad cases and Kyungpook National University's DRM system and Seoul National University's DRM system as domestic cases for copyright protection under open access circumstances. finally we will face up to the domestic open access reality and plan the future by presenting the development subject through dCollection license system analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.887-894
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• 2016

In the underwater acoustic communication channels, a multipath reflection becomes the cause of obstacle. To solve this problem, a rake receiver has been required for which one could take the time diversity. However, there is a concern about using incorrect path to recover signals with a high weighting value as underwater acoustic communication channels have severe time-variant property. In order to prevent these problem, a rake receiver is proposed which is based on BER(bit error rate) train sequence duration. The performance is evaluated through lake trials; there are three methods that are a proposed rake receiver, a conventional rake receiver, and a non-rake receiver. As a result, the number of bit errors in the proposed rake receiver, that of bit errors in the conventional rake receiver, and that of bit errors in the non-rake receiver is 8, 45, and 72, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.725-732
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• 2013

Recently, various applications for LED lightings are growing continuously due to their better performances such as low power consumption, longer life time, operation speed, controllability, high quality color rendering, and sustainability. However, in developing the high-powered LEDs illumination system, heat-sink problem is one of the important obstacle. In this paper, a heat-sink design with multi-layered structure for high-powered LEDs is proposed, which is composed of metal core PCB, heat-pipes, heat-sink plates, and fans. And also, in this paper, a design for LED controls using DMX512 protocols through RS-485 communications is proposed, which is considered as de facto international standard in LEDs illumination control and is widely used in landscape lighting and stage lighting. In this paper, LED control and its application techniques are introduced and the method of wireless remote control for main controller is proposed.

• Journal of Biosystems Engineering
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• v.41 no.2
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• pp.67-74
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• 2016

Purpose: Many tractors have adopted the horizontal control system designed to maintain the three-point mounted implements in horizontal position when they are tilted sideways. The control system rotates the implement in the opposite direction to the inclination of rear axle of the tractor. However, the current control system was found to have poor performance in accuracy and response. A new control system was therefore developed to improve the performance. Methods: The new control system was designed to get the response of the implement to be started earlier by using the tilt information from the front axle of the tractor. By this approach, the rotation of the implement can be adjusted as required to make it horizontal at the expected time, even though the response is slow. The optimal values of the control parameters for the new system were determined by computer simulation and validated by a performance test conducted with an obstacle of 120 mm height on a flat concrete surface. The performance of the control system was evaluated by the root mean square error (RMSE) of the rotation angle of the implement with respect to the actual inclination of the rear axle. Results: The new control system reduced the RMSE of the current control system by 44.6% indicating a high performance improvement. The inclination of the front axle was easily obtained from a sensor mounted on the front axle of the tractor and used as input to the new control system. Conclusions: The method of getting the response of the implement to be started earlier by utilizing the inclination information of the front axle can be applied to improve the performance of the current control system at least cost.

• Journal of Korean Library and Information Science Society
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• v.40 no.1
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• pp.433-449
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• 2009

The purpose of this study is to find out the factors which have interrupted Library Assisted Instruction in various schools' libraries and to analyze the factors by the tools and to propose the solutions to the obstacles for the desired Library Assisted Instruction. For doing this, some experimental processes had been made: firstly, to make the analysis model based on HPT for the improvement of the real LAI, secondly, to apply the model to LAI, to draw out the problems and to analyze them, and to propose the solutions. As the results of this study, the 5 solutions are presented; 1) LAIs should have the obvious and concrete teaching&learning objectives. 2) The supporting systems for LAI like the web community ought to be prepared. 3) External motivation systems, that is, teachers and teacher-librarians' performance assessment with LAI participation rate per year, should be developed. 4) The various, practical LAI programs should be developed. 5) The obscure refusal of teachers & teacher-librarians to LAI should be disappeared and the directors of schools should be confident of the LAI's educational, positive effects.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.289-302
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• 2005

The mobile agent has very various performance according to the element of communication number of times between hosts, quantity of transmission data agent's size, network state etc. specially, migration method is caused much effect in whole performance of distributed system. Most existing migration methods have simplicity structure that it moves doing to accumulate continuously result after achieving task by visiting host in the fixed order. Therefore, in case there are situation such as fault, obstacle, and service absence etc. This can be inefficient due to mobile agent increased network required time. In this paper, we design and implementation Multicast Migration Model for minimizing network required time by solving this problems. Multicast Migration Model includes components such as mobile agent including call module and naming agent, which provides object replication information and distributed server's location transparence. And we evaluate and compare with existing migration method applying prototype system to verify implemented migration model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2533-2540
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• 2013

In multihop cellular network environments, the mobility of nodes is a major obstacle to find a reliable routing path between a mobile node (MN) and the access node (AN). Therefore, in this paper, we propose a fast and reliable neighbor discovery protocol that enables the fast and reliable neighbor discovery by considering the node mobility in the multihop cellular network. The proposed neighbor discovery protocol inhibits the transmission of unnecessary control messages to quickly find a suitable neighbor node (NN) and performs a priority-based access control to transmit control messages without collision in the order of NN desirable to be selected. Simulation results show that the proposed neighbor discovery protocol can discover the NNs faster than the conventional scheme and select a more reliable relay node although the number of neighbor nodes increases and the node mobility increases.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.123-125
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• 2015

Wireless ad hoc network which is comprised of wireless nodes that have the limited communication range is utilized to monitoring disaster area, tracing object, and tactical system. But in the case of wireless node on the ground, a network performance decrease because wireless channel is affected from obstacle or the node deployment is restricted. In this paper, we consider wireless network based on UAV(Unmanned Aerial Vehicle) which has little spatial constraint and quickly deploy a position. We implement test-bed included ground nodes and UAV, and measure throughput and PDR(Packet Delivery Ratio) according to the usage of UAV. We show that network performance is improved by relaying data on UAV.

• The Transactions of the Korea Information Processing Society
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• v.5 no.7
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• pp.1855-1862
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• 1998

An Internet user obtains an IP address from DNS to access the host. But, Korean users must use English word order Domain that is not convenient for them. All existing systems have the reverse of the Korean word order and that is the obstacle to the spreading of Internet. So, the necessity of a Korean name system that well suited for Korean Internet user is increasing. In order to operate the proposed Korean Domain System with existing Domain Name Systems, we build a Korean to English transformation rule and Korean Domain Name composition rule. Also, we designed a STHOP for Korean word order processing. In a STROP, a SLDF transform a Korean SLD into English SLD, and a NFDNG makes this as an English word order. By using Korean Domain Name System proposed here, users could understand the embedded meaning of Domain Name with ease, and reluctance of Domain registration caused by similarity of organization names would be solved, Consequently. it could devote to the popularization of the Internet.