• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 한국퍼지및지능시스템학회 2000년도 춘계학술대회 학술발표 논문집
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• pp.288-291
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• 2000

In this paper we implement a robot system consisted of mobile tole robot to be controlled by client through web browser Newly Internet is connected to all network of the whole world. If client uses the network like this, client can control direction of a robot that is selected in free place. In this study, system is embodied in using robot that can move freely in plan place and cod camera that can grab robot image. System transmit image data of cod camera to java server that is placed in web server of internet that is used by client. Java server display incoming data in home page using java applet. Then web browser offer robot image to client and client send remote control signal to robot. Control signal is transmitted to robot by java server and robot receiving signal moves toward direction wanted by client.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제67권6호
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• pp.738-744
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• 2018

This paper proposes a low cost hot swap operation circuit of a parallel operation power supply for servers. Hot swap function for server power system is essential in 24 hour operation system such as internet data center, server, factory and etc. Server power supplies used in internet data centers have two or more parallel operations with the hot swap operation. However, the cost of the power supply is high because the controller IC for hot swap operation is very expensive. Therefore, this paper proposes a parallel-operated power supply with a low-cost hot swap controller for servers. The proposed system can operate hot swap function by using discrete devices and reduce the cost by more than 50%. A 1.2kW prototype system is implemented to verify the proposed low cost hot swap controller.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권1호
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• pp.22-37
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• 2013

Content distribution to a large number of concurrent clients stresses both server and network. While the server limitation can be circumvented by deploying server clusters, the network limitation is far less easy to cope with, due to the difficulty in measuring and balancing network load. In this paper, we use two useful network load metrics, the worst link stress (WLS) and the degree of interference (DOI), and formulate the problem as partitioning the clients into disjoint subsets subject to the server capacity constraint so that the WLS and the DOI are reduced for each session and also well balanced across the sessions. We present a network load-aware partition algorithm, which is practicable and effective in achieving the design goals. Through experiments on PlanetLab, we show that the proposed scheme has the remarkable advantages over existing schemes in reducing and balancing the network load. We expect the algorithm and performance metrics can be easily applied to various Internet applications, such as media streaming, multicast group member selection.

• Journal of Institute of Control, Robotics and Systems
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• 제9권4호
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• pp.340-346
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• 2003

Driven by the growth of the Internet and the increasing ubiquity of embedded computing systems, the embedded system is exploding in terms of it proliferation of products and the number of complex applications. Intelligent dedicated systems and appliances used in interface, monitoring, communications, and control applications increasingly demand the services of a sophisticated, state-of-the-art operating system. In the case of industrial controller, it is required to use a real-time operating system (RTOS) as a good building block to enable Internet connectivity. However, commercial RTOSes are increasingly less desirable due to their lack of standardization and their inability to keep pace with the rapid evolution of technology. In order to overcome these problems, we consider using embedded Linux and embedded web server. Availability of source code, reduced licensing, reliability, open source community support, as well as others, are key reasons for the use of embedded linux by embedded developers. In this paper, we develop embedded linux platform to control the industrial inverter with the Internet connecting feature. The method of web-based management is also proposed by using the embedded web server and Java applet. We show the feasibility of remote management for the commercial inverter controller with the proposed three-tier web-based remote management system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.19-24
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• 2009

In these days, security threat is ever increasing as computer systems and networking is everywhere. This paper is on the development of security scanner using search engine, with which site managers can easily check security vulnerability on their systems. Our security server automatically collects security-related information on the Internet, and indexes them in the database. To check the vulnerability of a customer server, the client system collects various system-specific information, and sends necessary queries to our security server for vulnerability checking. Up-to-date and site-specific vulnerability information is retrieved through the viewer, which allows the customer effectively to check and respond to security threat on client systems.

• The Transactions of the Korea Information Processing Society
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• 제7권8호
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• pp.2442-2451
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• 2000

Recently, there have been some trials to use a TV system as an Internet terminal for easier and more convenient use of Internet. Because a TV Web browser system has a TV display with a set-top box as an execution environment, it has some limits and there are specific requirements. The efficient implementation of the Web browser for TV needs the proxy server that includes HTML conversions for TV environments as well as general cash functions. In order to implement a Web environment on general TV and set-tops, we introduce a distributed structure using a proxy server and propose TV - HTML conversions as an important feature of the proxy server.

• Journal of Internet Computing and Services
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• 제3권1호
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• pp.91-99
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• 2002

Many companies and departments are increasingly concerned of searching their business information in correct and faster way as they share the information through the internet. LDAP has been proposed for directory server standards which supports storing, searching and managing the business information, and it has become a global standard. Current LDAP, however, cannot solve problem; such as server overloads and data synchronization. This paper describes the history and characteristics of LDAP, and proposes an architecture for solving those problem;. Since the proposed architecture is designed based on the existing LDAP architecture, it guarantees extensibility and portability of server configuration.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.924-944
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• 2017

Telecare Medical Information System (TMIS) helps the patients to gain the health monitoring information at home and access medical services over the mobile Internet. In 2015, Das et al proposed a secure and robust user AKA scheme for hierarchical multi-medical server environment in TMIS, referred to as DAKA protocol, and claimed that their protocol is against all possible attacks. In this paper, we first analyze and show DAKA protocol is vulnerable to internal attacks, impersonation attacks and stolen smart card attack. Furthermore, DAKA protocol also cannot provide confidentiality. We then propose a lightweight pseudonym AKA protocol for multi-medical server architecture in TMIS (short for PAKA). Our PAKA protocol not only keeps good security features declared by DAKA protocol, but also truly provides patient's anonymity by using pseudonym to protect sensitive information from illegal interception. Besides, our PAKA protocol can realize authentication and key agreement with energy-saving, extremely low computation cost, communication cost and fewer storage resources in smart card, medical servers and physical servers. What's more, the PAKA protocol is proved secure against known possible attacks by using Burrows-Abadi-Needham (BAN) logic. As a result, these features make PAKA protocol is very suitable for computation-limited mobile device.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제7권7호
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• pp.1434-1441
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• 2003

Recent technological advances in utilization and generalization of Internet have overcome some of the limitations of remote robot control range and real-time monitoring system. However, It needs Embedded system with control protocol or hardware which has avility to port the micro realtime operating system in robot control system communicate with remote controlled robot, because those system use the wireless LAM or Bluetooth as a network media. In this paper, we design and implement the wireless MODEM protocol and install it to the server system. Also, we implement a client system could control the remote robot through the server and we assure that this protocol and client/server system ate suitable for small size remote control system based on Internet.

• Journal of KIISE:Computing Practices and Letters
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• 제9권1호
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• pp.47-59
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• 2003

The Internet telephony service is one of the commercially successful Internet application services. VoIP technology makes the service come true. VoIP deploys H.323 or SIP as the standard protocol for the distributed multimedia services over the Internet in which QoS is not guaranteed. VoIP carries the packetized voice over the RTP/UDP/IP protocol stack. The data transmission trouble is caused by UDP when the service is provided in private networks and some ISP-provided Internet access networks in the private address space. The Internet telephony users in such networks cannot listen the voices of the other parties in the public Internet or PSTN. Making the problem more difficult, the Internet telephony service considered in this paper gets the incoming voice packets of every session through only one UDP port number. In this paper, three schemes including the terminal proxy, the gateway proxy, and the protocol translation are suggested to solve the problems. The design and implementation of the NAT proxy server based on gateway proxy scheme are described in detail.