• The Journal of the Korea Contents Association
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• v.3 no.3
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• pp.63-73
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• 2003

Today, in exponential growth of internet, the importance of file caching which could reduce the sun load, the volume of network traffic, and the latency of response has emerged. Actually, in one network, the traffic has reduced by using the cache and this means that file caching can improve the internet environment by cost a fraction of link upgrades. In this paper, we address a dynamic cache group configuration policy, to solve the scalable problem. The simulation result shows that the cache group using our proposal policy reduces the latency of response time and it means that out cache group configuration is more scalable than the static cache configuration.

• The KIPS Transactions:PartA
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• v.16A no.3
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• pp.181-188
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• 2009

Transcoding is one of core techniques that implement VoD services according to QoS. But it consumes a lot of CPU resource. A transcoding proxy transcodes multimedia objects to meet requirements of various mobile devices and caches them to reuse later. In this paper, we propose a service policy that reduces the load of transcoding multimedia objects by degrading QoS in a transcoding proxy. Due to the tradeoff between QoS and the load of a proxy system, a transcoding proxy provides lower QoS than a client's requirement so that it can accomodate more clients.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.391-394
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• 2006

This paper deals with the method will be able to support a common interface softly for the different with each other operating system users in next generation ubiquitous network. To controls in proxy servers that data portion be able to use commonly such as each different instruction, metaphor, image based on operating system, icons, it will be able to increases the efficiency of bandwidth use and minimizes a duplication transmission data from inside the bandwidth which is limited. Also it will be able to do method of common user interface provision to support seamless connectivity with each different network devices in the next generation.

• The Journal of Korean Association of Computer Education
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• v.12 no.4
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• pp.47-55
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• 2009

There are many researches considering mobile devices as resources in mobile grids. However, the mobile device has some limitations: wireless connection and battery capacity. So, the grid operations using mobile devices have lower reliability and efficiency than those in fixed grid environments. In this paper, we propose a job migration scheme using mobile devices to overcome these limitations. The proposed job migration scheme predicts failure condition during execution and takes checkpoints. Then, if the failure occurs on mobile device during execution, the executing job can be migrated to other mobile device by checkpoint information. To perform the proposed migration scheme, we establish a mobile device manager on a proxy server and a status manager on a mobile device. Connection, wireless signal strength and battery capacity of mobile devices are identified through two managers. The simulation results show improvement of efficiency and reliability during execution.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.57-61
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• 2014

Zeroboard is a public bulletin board that can support PHP and MySQL. It has been used by many people because it is easy to use, but there is no more updates after Zeroboard4. So, there is a problem that its administrator will have nothing to do about it if zeroboard has a vulnerability. In this paper, we will discuss about CSRF(Cross Site request Forgery) which is developed and expanded by XSS(Cross Site Scripting). Also, we will find CSRF attacks and suggest an alternative method using VM-ware. The main features and contributions of the proposed method are as follows. First, make an environment construction using VM-ware and other tools. Second, analyze and prepare vulnerabilities using Proxy server. Performance evaluation will be conducted by applying possible countermeasure.

• Convergence Security Journal
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• v.11 no.6
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• pp.9-15
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• 2011

It is difficult to identify attack requests from normal ones when those attacks are based on CSRF which enables an attacker transmit fabricated requests of a trusted user to the website. For the protection against the CSRF, there have been a lot of research efforts including secret token, custom header, proxy, policy model, CAPTCHA, and user reauthentication. There remains, however, incapacitating means and CAPTCHA and user reauthentication incur user inconvenience. In this paper, we propose a method to detect CSRF attacks by analyzing the structure of websites and the usage patterns. Potential victim candidates are selected and website usage patterns according to the structure and usage logs are analyzed. CSRF attacks can be detected by identifying normal usage patterns. Also, the proposed method does not damage users' convenience not like CAPTCHA by requiring user intervention only in case of detecting abnormal requests.

• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.11-25
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• 2011

In ubiquitous computing environment, OSGi has applied to many areas such as digital mobile phones, vehicles, telematics, embedded appliances, residential gateways, industrial computers, desktop PCs, and high-end servers including mainframes. Therefore, interoperability is required for remote OSGi services which are built on various devices. In this paper, we proposed a method which was able to interoperate remote OSGi services using RMI paradigm. RMI is a representative middleware technology in distributed computing environment. The suggested method is based on the standard OSGi technology. It is possible to provide remote OSGi service registration, finding, and binding methods which were suitable for the OSGi service-oriented architecture. We also provided reliability of the dynamic remote OSGi services by maintaining consistent properties of them, and we could provide location transparency of the remote OSGi services by generating proxy bundles and proxy services dynamically.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.208-218
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• 2008

We are sure that RFID system should be a widely used automatic identification system because of its various advantages and applications. However, many people know that invasions of privacy in RFID system is still critical problem that makes it difficult to be used. Many works for solving this problem have focused on light-weight cryptographic functioning in the RFID tag. An agent scheme is another approach that an agent device controls communications between the tag and the reader for protecting privacy. Generally an agent device has strong security modules and enough capability to process high-level cryptographic protocols and can guarantees consumer privacy. In this paper, we present an enhanced mobile agent for RFID privacy protection. In enhanced MARP, we modified some phases of the original MARP to reduce the probability of successful eavesdropping and to reduce the number of tag's protocol participation. And back-end server can authenticate mobile agents more easily using public key cryptography in this scheme. It guarantees not only privacy protection but also preventing forgery.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2533-2540
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• 2009

Performance of processing protocols is one most important goal in a network or systems constituting the network. Measurement of performance, thus, is an essential element to not only establish the network but also develop systems. A projection in vector mathematics is the transformation of points and lines in one plane onto another plane by connecting corresponding points on the two planes with parallel lines. This is a method, as an application of vector mathematics, which is widely used in engineering as well to consider elements dedicated to the measurement object. This paper proposes a sound methodology for measuring the performance of the SIP protocol, which is based on the projection. The SIP protocol is a typical standard protocol for call-processing in the internet telephony of Next Generation Convergence Network. Owing to use the projected protocol which excludes unnecessary operation paths, the methodology can be effective in implementation and resource utilization. This paper also presents a process based on the proposed methodology to measure the performance of a SIP proxy server.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.11-19
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• 2019

Recently, hybrid CDN/P2P video streaming architecture is specially designed and deployed to achieve the scalability of P2P networks and the desired low delay and high throughput of CDNs. In this paper, we propose a cooperative video streaming and active node buffer management technique in hybrid CDN/P2P architecture. The key idea of this streaming strategy is to minimize network latency such as jitter and packet loss and to maximize the QoS(quality of service) by effectively and efficiently utilizing the information sharing of file location in CDN's proxy server which is an end node located close to a user and P2P network. Through simulation, we show that the proposed cooperative video streaming and active node buffer management technique based on CDN and P2P network improves the performance of realtime video streaming compared to previous methods.