• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.334-340
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• 2004

In this paper, a Web-based management system for the building network is described. A multi-protocol converter based on SoC and embedded Linux is designed. The open source licensing, reliability, and broad hardware support are key reasons for use of embedded Linux in embedded industry. The multi-protocol converter integrates control network of RS-485 and LonWorks devices through TCP/IP protocol for a client with Java applet. The system consists of three-tier architecture, such as a client, a server that is performed on a multi-protocol converter, and control devices. The developed system includes the inverter motor control system with modbus protocol for the RS-485 network. The experiment results show that the multi-protocol converter using embedded Linux is a flexible and effective way to builda Web -based monitoring and control system.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2109-2111
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• 2003

In this paper, It is studied to monitor the remote system status using HTTP(HyperText Transfer Protocol) object communication. This system is organized by three different part depending on functionality - server part, client part, controller part. The JAVA technology is used to composite the server part, the client part and C language is used for a controller.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.11-21
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• 2004

To authorize IPSec-VPN Client in Client-to-Gateway type of the IPSec-VPN system, it can be normally used with ID/Password verification method or the implicit authorization method that regards implicitly IPSec-VPN gateway as authorized one in case that the IPSec-VPN client is authenticated. However, it is necessary for the Client-to-Gateway type of the IPSec-VPN system to have a more effective user authorization mechanism because the ID/Password verification method is not easy to transfer the ID/Password information and the implicit authorization method has the vulnerability of security. This paper proposes an effective user authorization mechanism using an attribute certificate and designs a user authorization engine. In addition, it is implemented in this study. The user authorization mechanism for the IPSec-VPN system proposed in this study is easy to implement the existing IPSec-VPN system. Moreover, it has merit to guarantee the interoperability with other IPSec-VPN systems. Furthermore, the user authorization engine designed and implemented in this paper will provide not only DAC(Discretional Access Control) and RBAC(Role-Based Access Control) using an attribute certificate, but also the function of SSO(Single-Sign-On).

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.65-65
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• 2000

For Video on Demand(VoD) servers, a design of an efficient scheduler is important to the support a large number of clients having various playback speeds and receiving rates. In this paper, we propose the scheduling algorithm to handle establishing deadlines and selection using the earliest deadline first. To establish deadlines and selections, the period of the receiving rates for each client is located between the over-max receiving rate and the over-playback rate. To avoid video starvation and the buffer overflow of each client, the proposed algorithm guarantees providing the admission control. Because of establishing deadlines and selection, period of each client receiving is between one over max receiving rate and one over play back rate. Using Virtual Buffer in server, scheduling load is reduced. The efficiency of the proposed algorithm is verified using a Petri Net_Based simulation tool, Exspect.

• Proceedings of the Safety Management and Science Conference
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• 2002.11a
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• pp.157-163
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• 2002

Automated manufacturing systems are applied to shop floors as a tool for the increase of productivity and quality and the decrease of manufacturing lead times and industry accidents. One of the most important issue of the present day is the application of Internet. The development of Internet technologies makes manufacturing enterprises break spacial barriers between users and shop floors, and collect various field data in remote sites. In this research, an Internet-based remote control system for a small-sized automated storage and retrieval system is developed for the purpose of real-time monitoring and control of automatic production equipment. The developed system has a client-server architecture and transmits real-time images of the automated storage and retrieval system to a client by ar CCD camera connected to a server. Based on the transmitted images, the client sends commands to PLC of the server, and part storage and retrieval tasks are executed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.61-66
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• 2009

In this paper, an example of implementation of a embedded system technology for web based monitoring and control system is presented. For it interfaces with target board as an embedded system was developed, which was applied to specific green room model and verified of its usefulness. We implemented client/server socket programs using Java classes, and web based green room monitoring and control system as an user interface using JavaApplet. The implemented system did send information of green room model to client programs well on TCP/IP and control signals from client to green room model well too.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.99-107
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• 2002

Broadcast disks are suited for disseminating information to a large number of clients in mobile computing environments. In broadcast disks, the server continuously and repeatedly broadcasts all data items in the database to clients without specific requests. The clients monitor the broadcast channel and retrieve data items as they arrive on the broadcast channel. The broadcast channel then becomes a disk from which clients can retrieve data items. In this paper, we propose a cache conscious concurrency control ($C^4$) scheme to preserve the consistency of client transactions, when the values of broadcast data items are updated at the server. $C^4$ scheme is novel in the sense that it can reduce the response time of client transactions with minimal control information to be broadcast from the server. This is achieved by the judicious caching strategy of the clients.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1173-1178
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• 2007

Ubiquitous sensor network (USN) is composed of many sensor nodes which are one of the simplest form of embedded system. In developing the sensor network system, a debugging tool is necessary to test and verify the system. Recently, a so-called packet analyzer has been developed for this purpose, and it supports IEEE 802.15.4 which is considered as the standard for the sensor network protocols. The major function of the packet analyzer is to take RF packets from sensor nodes and show the structure and the data of the packets graphically to the user. However, the conventional packet analyzers do not support remote control because they require a USB interface along with a personal computer. To make it available for remote control, we propose a new packet analyzer based on a server-client scheme in which a server program is implemented on embedded Linux and a client program is implemented on Windows for convenient use.

• Journal of IKEEE
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• v.13 no.3
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• pp.87-94
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• 2009

TETRA(TErrestrial Trunked RAdio) is the wireless communication system generally adopted to public network and backbone network, as the technology of Trunked Radio System specified by ETSI(European Telecommunications Standards Institute) and currently adopted to the Electric Power IT Backbone Network in Korea. IEC 61850 is the protocol proposed for SAS(Substation Automation System) of SCADA(Supervisory Control And Data Acquisition) system. In this paper, IEC 61850 Server and Client simulator are used based on Linux operating system. The multi-functional gateway, which transforms the communication based on TCP/IP between IEC 61850 Server Simulator and Client Simulator to the one based on TETRA Packet Data Service, is developed such that IEC 61850 SCADA system is constructed based on TETRA.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.738-749
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• 2011

In this paper, we study QoS(Quality of Service) control protocols and the effect using MAC/PHY parameters of client device in mobile network. We proposes the way of controling the bit-rate by estimating the channel condition of the client with measured MAC/PHY parameters which is sent from the client. With the proposed method, more accurate available bit-rate can be estimated compared to conventional protocol, RTCP(Real-time Transport Control Protocol). The accurate bit-rate estimation can decrease wasted bit-rate and transport delay. In the result of the advantages, the transported video quality can be enhanced. In this paper, we show the effects of enhancement using client's the field data measured in WiMAX.