• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10c
• /
• pp.307-309
• /
• 2004

본 논문에서는 차세대 OVPN(Optical Virtual Private Network)에서 제어 프로토콜인 LMP(Link Management Protocol)를 IPsec(If Security Protocol)을 사용하여 보안성을 제공하는 메커니즘의 문제점을 제시한다. 그리고 이에 대한 해결책으로, IPsec를 사용하지 않고 보안성을 제공하면서 빠른 속도로 처리되는 확장된 LMP 메커니즘을 제안한다.

• Journal of Digital Contents Society
• /
• v.16 no.4
• /
• pp.615-622
• /
• 2015

Recently virtual advertising is located in an important area of interest in the TV market by convenience of application and reduction of cost. The methods of inserting a virtual advertising in broadcasting are Up-link that method insert the image through the production equipment of the broadcasting station and dispatch equipment and technical personnel in the shooting and Down-streaming that method insert a virtual image automatically in relay video using image processing technology. In recent years, the image processing technology is an important research area in the virtual advertising area for automatically insertion of advertising images. In this paper, we propose the method to extract less-informative region in sports video using image processing. The proposed method extracts less-Informative region through rectangle detection of Hough transform and analysis of color histogram distribution.

• Journal of KIISE:Computing Practices and Letters
• /
• v.8 no.2
• /
• pp.219-230
• /
• 2002

One of the most important functions digital libraries need to offer is to help users find necessary information in a distributed environment in the most efficient and effective manner. In order to meet the goal, it is desirable to link scattered pieces of information and present them as a logically coherent whole when the user wants it, so that he or she doesn't need to know their physical location. The virtual document is an integrated document that the total or part of the physical documents stored in a specific repository are linked dynamically. Our MIRAGE-III digital library system provides a content-based retrieval of physical documents and the virtual documents in XML. This system provides a retrieval of partial documents, attributes and hierarchical structures and linked-documents based in structured documents like XML or SGML. In this paper we describe a methodology of design and implementation of the query processor and retrieval server in the MIRAGE-III digital library system.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.10
• /
• pp.2627-2640
• /
• 1998

In this paper, we analyze the performance of the virtual cell system[1] for the transmission of IP datagrams in mobile computer communications. A virtual cell consistsof a group of physical cells shose base stationsl are implemented b recote bridges and interconnected via high speed datagram packet switched networks. Host mobility is supported at the data link layer using the distributed hierachical location information of mobile hosts. Given mobility and communication ptems among physical cells, the problem of deploying virtual cells is equivalent to the optimization cost for the entire system where interclster communication is more expesive than intracluster communication[2]. Once an iptimal partitionof disjoint clusters is obtained, we deploy the virtual cell system according to the topology of the optimal partition such that each virtual cell correspods to a cluser. To analyze the performance of the virtual cell system, we adopt a BCMP open multipel class queueing network model. In addition to mobility and communication patterns, among physical cells, the topology of the virtual cell system is used to determine service transition probabilities of the queueing network model. With various system parameters, we conduct interesting sensitivity analyses to determine network design tradeoffs. The first application of the proposed model is to determine an adequate network bandwidth for base station networking such that the networks would not become an bottleneck. We also evaluate the network vlilization and system response time due to various types of messages. For instance, when the mobile hosts begin moving fast, the migration rate will be increased. This results of the performance analysis provide a good evidence in demonsratc the sysem effciency under different assumptions of mobility and communication patterns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.3
• /
• pp.311-318
• /
• 2004

It is required to design the RF link with sufficiently stable signal margin to minimize bit errors and improve the quality of received data in the telemetry system modulated digitally like PCM/FM. In case of the vehicle flying at a high speed, the variation of the gain pattern between transmitting and receiving antenna and the fee space loss due to flight distance cause the fluctuation of link. In this paper, KSR(Korea Sounding Rocket)- III, the first domestic liquid rocket which was successfully launched in Nov. 2002 is introduced. The SNR(signal-to-noise ratio) variation of the telemetry signal which was measured at S-band ground station, the one which was simulated considering the flight trajectory, and the attitude variation such as roll, pitch and yaw are compared, analyzed, and agree very well. In addition, two virtual flying situations are simulated and evaluated-only one antenna is equipped in one case, and rocket is roll-free in the other.

• Journal of Power Electronics
• /
• v.6 no.1
• /
• pp.52-66
• /
• 2006

This paper proposes a wind energy conversion system connected to a grid using a self-excited induction generator (SEIG) based on the maximum power point tracking (MPPT) control scheme. The induction generator (IG) is controlled by the MPPT below the base speed and the maximum energy can be captured from the wind turbine. Therefore, the stator currents of the IG are optimally controlled using the indirect field orientation control (IFOC) according to the generator speed in order to maximize the generated power from the wind turbine. The SEIG feeds a (CRPWM) converter which regulates the DC-link voltage at a constant value where the speed of the IG is varied. Based on the IG d-q axes dynamic model in the synchronous reference frame at field orientation, high-performance synchronous current controllers with satisfactory performance are designed and analyzed. Utilizing these current controllers and IFOC, a fast dynamic response and low current harmonic distortion are attained. The regulated DC-link voltage feeds a grid connected CRPWM inverter. By using the virtual flux orientation control and the synchronous frame current regulators for the grid connected CRPWM inverter, a fast current response, low harmonic distortion and unity power factor are achieved. The complete system has been simulated with different wind velocities. The simulation results are presented to illustrate the effectiveness of the proposed MPPT control scheme for a wind energy system. In the simulation results, the d-q axes current controllers and DC-link voltage controller give prominent dynamic response in command tracking and load regulation characteristics.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.4 no.1
• /
• pp.68-75
• /
• 2011

The performance of peripheral devices is improving rapidly to meet the needs of users for multimedia data. Therefore, the peripheral interface with wide bandwidth and high transmission rate becomes necessary to handle large amounts of data in real time for multiple high-performance devices. PCI Express is a fast serial interface with the use of packets that are compatible with previous PCI and PCI-X. In this paper, we design and verify general peripheral interface using serial link. It includes two kinds of traffic class (TC) labels which are mapped to virtual channels (VC). The design adopts TC/VC mapping and the scheme of arbitration by priority. The design uses a packet which can be transmitted through up to four transmission lanes. The design of general peripheral interface is described in Verilog HDL and verified using ModelSim. For FPGA verification, Xilinx ISE and SPARTAN XC3S400 are used.We used Synopsys Design Compiler as a synthesis tool and the used library was MagnaChip 0.35um technology.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37A no.11
• /
• pp.979-985
• /
• 2012

The design of an efficient scheduler is a key design factor in IEEE 802.16m systems, in order to support services with various QoS smoothly. Although conventional studies of schedules have been suggested, those had problems that are not able to satisfy the delay condition and make the through-put declined, because they only focused on a specific action scenario rather than reflecting practical action scenarios which have real-time and non-real-time traffics variously. In this paper, an efficient uplink scheduling algorithm is proposed for IEEE 802.16m system by introducing the concepts of Virtual Time(VT) and Virtual Finish Time(VFT) based priority determination, and separate buffers for each QoS class in the mobile terminal. Simulation results showed that the proposed scheme had satisfied the delay requirement of real-time services even with improved throughput performance compared to conventional methods.

• Journal of Convergence Society for SMB
• /
• v.6 no.4
• /
• pp.17-23
• /
• 2016

With the advance of ICT, the Internet has been creating new services in various fields. However, due to the architectural problem of the Internet, it may inhibit the development of network architectures and various services. Network virtualization is being investigated as an alternative to overcome the architectural problem of the Internet and a virtual network resource allocation algorithm is a very important issue. In this paper, we propose a multiple path resource allocation algorithm with shared backup bandwidth in order to overcome single link failure. It will be improved survivability of the virtual networks. Through our experiments, we confirmed that the multi-path creation time of the proposed algorithm has about 50% performance improvement than previous works.

• Korean Institute of Interior Design Journal
• /
• no.12
• /
• pp.40-49
• /
• 1997

What's the direction of INTERIOR ARCHITECTURAL DESIGN in 21 Century High Tech\ulcorner The purpose of this research is to show not only practical use of Computer Graphic(CG) as simple tool function, but offering conversation with computer and other ways of method. When we consider poor CG market, investment on the research of VR(Virtual Reality) is the most urgent. The investment on VR will solve various problems. Firstly. It will solve the problems drived from Interior design process by making spatial images like reality. Secondly, It will solve high wages and financial difficulties caused by raise cost funds. Thirdly, It prevents in a road from foreign company that will bring enormous program, caused by opening the domestic market. Also, It help interior designer check in advance the problems in constructure through showing him a supposed imagination including the system and location of equipments. But it is reality that even ordinary American can't offer VR(Virtual Reality) System. We should have noted that it is normal to spend 10 billion won for such presentation as Model House in the large corporation. We must acknowledge that it is such a waist of money nationally. Therefore, investment on CG & VR System is essential in order to save cost more effective presentation & interior design. We will see great result within a year. As we can see, there is huge area we have make develop. One of them is specific technical plan on VR System and study of flow chart. We close with simple methodological way to use VR System and will study Computer System. Which is fitting to CG that we have to solve the link of hardware and software on VR System\ulcorner We know from the cases in other countries that continuous research on this subject has great value for Interior Architectural Design and its effective use. When we try hard not only for methodological use but practical use, the purpose of CG and VR System will be a factor to contribute on this subject for better Interior design & presentation.