• Journal of the Korea Computer Industry Society
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• v.2 no.11
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• pp.1383-1394
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• 2001

Through the extension of damages caused by hacking and computer virus, although security control has been emphasized, hackers' capability exceeded the security controllability. The basic security setup of server system will be free from the damages by primary and intermediate level which are the major group. It should be noted that security condition of most middle-sized and personal systems is widely open for hacker's intrusion. There is no perfect information system either software-wise or hardware-wise. It has to be recognized that our systems will be attacked easily by the hackers and computer virus. Computer users are demanded to be prepared for these types of surprise attacks. In this paper, I will propose a formation of Bastion server. This will protect risks from inside & outside intrusion which have been known till today.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.55-59
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• 2004

Recently the wireless-internet has been spreading extensively. People are spending a large part of their time gaining access to information using a mobile device. However. limited process speed. low bandwidth, the low battery capacity of mobile devices and a high rate of wireless network errors brings out many overheads during service time with server for service. In this paper, we suggest an autonomous service delivery system. which provides mobile agent capability to users that can not maintain a connection. We have developed the system based on java mobile agent technology. Using this system, we can provide more effective services to users when the user is sending requirements of service through a mobile device that has limited resources and can manage the contact server dynamically when new services are added.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.38-44
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• 2013

In this paper, we designed and implemented a mobile video transmission device with 1080i resolution and 30fps frame rate using wireless multi-access technologies. The video acquisition delay time of 16us and jitter of 21ms for this equipment were obtained, respectively. The device is designed to access various communication networks. In order to evaluate the performance of its video transmission capability, a server and monitoring viewer are implemented. In the performance test using LTE network, 211ms delay time was obtained at 3Mbps transmission. Rendering of 1fps frame rate at the 265kbps transmission was confirmed for the transmission test using Inmarsat network.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.608-620
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• 2000

A web based E-mail system consists of serves which supply mail accounts and service, and clients which take part of interfacing with users. The web browsers such as Netscape Navigator and Internet Explorer are the popular clients. Users who cannot afford to get an E-mail id in general mail servers are, therefore, able to reach a e-mailing service in the web environment by using client programs in connection with a mail server. Although the quality of service has been upgraded a lot in recent days, it doesn't provide with satisfactory services anymore. In this paper, we intend to design a mail agent system based on the web environment. Through this system we could reach a convenient user interface based on Internet Explorer and could easily access administratory environment on the basis of NT Server 4.0. Using the service engine dominent in mail agent system, it could provide with convenient user interfacing tools like responding the absence of users, mail filtering and refusing messages, etc. And it would ultimately make possible a constant system security, by preventing system failure phenomena caused by extraordinary uses beyond its capability.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.435-446
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• 2001

In this paper, a new fairness control method is proposed to distribute DQDB-SR (Distributed-Queue Dual-Bus with Slot Reuse) network bandwidth fairly to all stations on client-server environments. By using an access limit that follows a characteristic of client-sever load patterns and a bandwidth borrowing and returning mechanism, the proposed mechanism imparts fairness bandwidth control capability to DQDB-SR. To implement the proposed mechanism, we find the optimal placement of erasure nodes that maximizes network capacity for DQDB-SR, and calculate the access limit. At overload conditions, simulation results show that the proposed mechanism does not deteriorate network throughput, and outperforms other fairness control mechanisms in a success rate and an average packet transfer delay.

• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.15-24
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• 2007

As a single video server exposes its limitation in scalability, capability, fault-tolerance, and cost-efficiency, solutions of this limitation emerge. However, these solutions have their own problems that will be discussed in this paper. To solve these problems and exploit various video silvers, we designed a parallel multimedia system architecture that supported a content-aware routing to heterogeneous personal computer (PC), operating system (OS), video servers through a HTTP-level redirection. We also developed a prototype, added different video servers into the prototype, and measured its overheads.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.139-142
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• 1996

A remotly controlled interactive magnetic resonance imaging (MRI) has been tried using the World Wide Web. For this purpose, an HTTP server is developed on the host computer of the MRI system. Video and audio conferencing capability is also included for the experiment. Using the developed system, MRI imaging has been successfully carried out at the Signal Processing Lab in the Kwangwoon University with the remote MRI system located at the Medical Image Research Center in the KAIST in Daejon.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.926-932
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• 2007

Various research groups proposed various architecture of hardware VPN for the high performance VPN system. However, the VPN based on hardware researcher are focused only on the encryption acceleration. Soft based VPN is only useful when the network connection is slow. We have to consider the hardware performance (encryption/decryption processing capability, packet processing, architecture method) to implement hardware based VPN. In this paper, we have analysed architecture of hardware, consideration and problems for high-speed VPN system, From the result, we can choose the proper design guideline.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.153-164
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• 2004

Under a large-scale client-server service environment, e.g., online games, encrypting data for acquiring information security often causes overload to the server and hence degradation of the service itself. Therefore, for reducing encryption payload, it is necessary to use adequately an efficient encryption scheme with respect to the security requirements of transmission data. In this paper, we propose a packet encryption scheme using multiple cryptosystems to realize such capability, which assigns a different cryptosystem according to the security requirements level. The proposed encryption scheme is applicable to internet services with heavy traffic ratios in which different kinds of data packets are incessantly transmitted between clients and servers. To show its effectiveness and superiority, the performance of the proposed encryption scheme is verified by experiments.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.395-404
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• 2005

There have been large concerns about survivability defined as the capability of a system to perform a mission-critical role, in a timely manner, in the presence of attacks, failures. In particular, One of the most important core technologies required for the design of the ITS(Intrusion Tolerance System) that performs continuously minimal essential services even when the computer system is partially compromised because of intrusions is the survivability one of In included the dependability analysis of a reliability and availability etc. quantitative dependability analysis of the In. In this Paper, we applied self-healing mechanism utilizing two factors of self-healing mechanism (fault model and system response), the core technology of autonomic computing to secure the protection power of the ITS and consisted of a state transition diagram of the ITS composed of a primary server and a backup server. We also defined the survivability, availability, and downtime cost of the ITS, and then performed studies on simulation experiments and two cases of vulnerability attack. Simulation results show that intrusion tolerance capability at the initial state is more important than coping capability at the attack state in terms of the dependability enhancement.