• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.65-74
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• 2012

The QoS guarantee for the forward link in satellite communication networks is very important because there are a variety of packets with multiplexing. Especially, the packets are processed depending on the available bandwidth in satellite network changing the wireless channel state in accordance with weather condition. The DVB-S2 increases the transmission efficiency by applying the adaptive coding and modulation (ACM) techniques as a countermeasure of rain attenuations. However, the channel estimation algorithm is required to support the ACM techniques that select the MODCOD values depending on the feedback data transmitted by RCSTs(Return Channel via Satellite Terminal) because satellite communication networks have a long propagation delay. In this paper, we proposed the channel estimation algorithm using rain attenuation values and reference data and the packet scheduling scheme to support the QoS and fairness. As a result of performance evaluation, we showed that proposed algorithm exactly predicts the channel conditions and supports bandwidth fairness to the individual RCST and guarantees QoS for user traffics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2629-2636
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• 2015

Recently Big Data management have a rapid increases interest in IT field, much research conducting to solve a problem of real-time processing to Big Data. Lots of resources are required for the ability to store data in real-time over the network but there is the problem of introducing an analyzing system due to aspect of high cost. Need of redesign of the system for low cost and high efficiency had been increasing to solve the problem. In this paper, the document type of database, MongoDB, is used for design a log management system based a document type of database, that is good at big data managing. The suggested log management system is more efficient than other method on log collection and processing, and it is strong on data forgery through the performance evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1962-1969
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• 2009

During past 20 years we have witnessed brilliant advances in major components of computer system, including CPU, memory, network device and HDD. Among these components, in spite of its tremendous advance in capacity, the HDD is the most performance dragging device until now and there is little affirmative forecasting that this problem will be resolved in the near future. We present a new approach to solve this problem using the NAND Flash memory. Researches utilizing Flash memory as storage medium are abundant these days, but almost all of them are targeted to mobile or embedded devices. Our research aims to develop the NAND Flash memory based storage system enough even for enterprise level server systems. This paper present structural and operational mechanism to overcome the weaknesses of existing NAND Flash memory based storage system, and its evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1439-1444
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• 2013

Recently, as the use of the applications like online banking and stock trading is increasing by the rapid development of the network, security of data content is becoming more and more important. Accordingly, public key or symmetric key encryption algorithm is widely used in open networks such as the internet for the protection of data. Generally, public key cryptographic systems is based on two famous number theoretic problems namely factoring or discrete logarithm problem. So, public key cryptographic systems is relatively slow compared to symmetric key cryptography systems. Among public key cryptographic systems, the advantage of ECC compared to RSA is that it offers equal security for a far smaller key. For this reason, ECC is faster than RSA. In this paper, we propose a efficient key generation method for elliptic curve cryptography system based on the real number field.

• The KIPS Transactions:PartC
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• v.15C no.1
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• pp.69-78
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• 2008

In this paper, we propose the effective exchange-method of a user profile for adapted contents services in the contents adaptation system. The profiles continuously exchange among the devices of contents adaption system for providing the adapted contents to a user. The profile should be also exchanged according to periodic, aperiodic, event, request and response. Consequently, a lot of network traffic occur and computing power require. Solving theses problem, the profile exchange research needs. we analyze creation information, exchange information, and exchange form of the profile information in contents adaptation system for effective profile exchange and define exchange procedure of the profile using the analyzed profile information. we also propose providing method of the profile configured information for decreasing profile processing time and user setting method for decreasing the number of profile transmission. As a result of performance evaluation, providing method of the profile configured information reduce 7% processing time and user setting method decrease the number of profile transmission are effective to exchange the profile.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.29-36
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• 2002

For the efficient collaboration awareness, the CSCW (Computer-Supported Cooperative Work) systems provide functions such as telepointing, snap-shot, and document/project tracking. Among these, telepointing allows an event occurrence on the shared window of a local computing system to be presented in remote computing systems. Although telepointing has been mentioned in the literature, few research papers deal with the functional requirements and protocols for telepointing. This parer describes the functional requirements and payload format for RTP (Real-Time Transport Protocol)-based telepointing. In order to evaluate the performance of the proposed RTP-barred telepointing, we have implemented a whiteboard and compared it with that of the Microsoft Netmeeting. The evaluation results show that the proposed telepointing performs better in terms of CPU usage and the amount of network traffic.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.577-581
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• 2009

Recently, various new services based on ubiquitous computing and networking have been developed. In this paper, we contrive Adaptive PIR(Pyroelectric Infrared Radiation) Detection Algorithm (APIDA), a PIR-sensor based digital signal processing algorithm, that detects the movement of an invading object by the recognition of heat change in the detection area, since the object like person or car emits heat(i.e., infrared radition), We devised APIDA as a highly reliable signal processing algorithm that increases the successful detection rate and decreases the false alarm rate in the intruding object detection. According to performance evaluation experiment, APIDA shows the successful detection rate of 90% and low false alarm in the plain area.

• Journal of Korea Multimedia Society
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• v.14 no.4
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• pp.567-576
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• 2011

In current Web 2.0 environment, one of the most core technology is social bookmarking which users put tags and bookmarks to their interesting Web pages. The main purpose of social bookmarking is an effective information service by use of retrieval, grouping and share based on user's bookmark information and tagging result of their interesting Web pages. But, current social bookmarking system uses the number of bookmarks and tag information separately in information retrieval, where the number of bookmarks stand for user's degree of interest on Web contents, information retrieval, and classification serve the purpose of tag information. Because of above reason, social bookmarking system does not utilize effectively the bookmark information and tagging result. This paper proposes a Web contents ranking algorithm combining bookmarks and tag information, based on preceding research on associative tag extraction by tag clustering. Moreover, we conduct a performance evaluation comparing with existing retrieval methodology for efficiency analysis of our proposed algorithm. As the result, social bookmarking system utilizing bookmark with tag, key point of our research, deduces a effective retrieval results compare with existing systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.447-453
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• 2004

In this paper, we propose a new system to block harmful Internet information based on IP spoofing. The proposed system is located on a organization's internal network and monitors all outgoing traffic and lets all this traffic go outside. Once the proposed system detects a host's access to a harmful site, it sends the host a pseudo RST packet that pretends to be the response from the harmful site, and prevents the connection between the host and the harmful site. The proposed software system is installed on only a server, and need not be installed on user hosts at all. Thus we can maintain and upgrade the blocking system easily. The performance evaluation of the proposed system shows that it effectively blocks the access to the harmful sites. Since the proposed system is based on IP spoofing, it can be used badly as a hacking tool. Finally we propose some methods to eliminate this possibility.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.93-99
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• 2019

In this paper, we propose a smart meter that uses GRU model, which is one of artificial neural networks, for the efficient energy management. We collected power consumption data that train GRU model through the proposed smart meter. The implemented smart meter has automatic power measurement and real-time observation function and load control function through power consumption prediction. We determined a reference value to control the load by using Root Mean Squared Error (RMS), which is one of performance evaluation indexes, with 20% margin. We confirmed that the smart meter with automatic load control increases the efficiency of energy management.