• Journal of Internet Computing and Services
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• v.22 no.5
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• pp.17-26
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• 2021

This paper is about a physical layer frame security technique using OFB-style encryption/decryption with AES algorithms on Gigabit Ethernet network. We propose a data security technique at the physical layer that performs OFB-style encryption/decryption with AES algorithm with strong security strength when sending and receiving data over Gigabit Ethernet network. Generally, when operating Gigabit Ethernet network, there is no security features, but data security is required, additional devices that apply this technique can be installed to perform security functions. In the case of data transmission over Gigabit Ethernet network, the Ethernet frames conform to IEEE 802.3 specification, which includes several fields to ensure proper reception of data at the receiving node in addition to the data field. When encrypting, only the data field should be encrypted and transmitted in real time. In this paper, we show that only the data field of the IEEE802.3 frame is encrypted and transmitted on the sending node, and only the data field is decrypted to show the plain text on the receiving node, which shows that the encryption/decryption is carried out correctly. Therefore, additional installation of devices that apply this technique can increase the reliability of the system when security for data is required in Ethernet network operating without security features.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1074-1079
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• 1999

A high performance CMOS receiver for 155.52 Mbps STM-1 digital communication has been designed and fabricated. The ASIC operates properly with 155.52 MHz clock frequency in case of the data loss due to some system error such as transmission line open or data transfer fail. Also it operates properly in case the system starts after the power failure or system maintenance. The designed circuit has especially PLL based self oscillation loop which operates on abnormal environment which is added to main oscillation loop. The measured results show that the circuit operates well with 153.52 MHz clock frequency not only on normal environment but also on abnormal environment. Rms jitter of the PLL loop is about 23 ps.

• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.722-728
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• 2011

Most services need to have authentication protocols to verify users' eligibility in the network environment. For this, a lot of user authentication protocols have been researched and developed. Two of them, SPMA and I-SPMA protocols, introduced the lack of mutual authentication and vulnerability to the reply attack of the prior protocols and suggested revised protocols. Nevertheless, these protocols did not mention about the critical problem caused when the server and the client lose synchronization on the secret information between them. Therefore, in this paper, we analyze the security characteristics of the existing protocols and prove the vulnerability to the synchronization of the protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2451-2458
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• 1997

Adaptive channel equalization complished without resorting to a training sequence is known as blind equalization. In this paper, in order to increase the speed of the convergence and to reduce the steady-state mean squared error simulatneously, we propose the multi-stage DD(decision-direct) algorithm derived from the combination of the Sato algorithm and the decision-directed algorithm. In the starting stage, the multi-stage DD algorithm is identical to the Sato algorithm which guarantees the convergence of the equalizer. As the blind equalizer converges, the number of the level of the quantizers is increased gradally, so that the proposed algorithm operates identical to the decision-directed algorithm which leads to the low error power after the convergence. Therefore, the multi-stage DD algorithm obtains fast convergence rate and low steady state mean squared error.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.650-659
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• 2004

Domestic wireless network environment is changing rapidly while adapting to meet service requirements of users and growth of market. As a result, reliable data transmission using TCP is also expected to increase. Since TCP assumes that it is used in wired networt TCP suffers significant performance degradation over wireless network where packet losses are not always result of network congestion. Especially RTO imposes a great performance degradation of TCP. In this paper, we propose DAC$^{＋}$ and EFR in order to prevent performance degradation by quickly detecting and recovering loss without RTO during fast recovery. Compared with TCP NewReno, proposed scheme shows improvements in steady-state in terms of higher fast recovery Probability and reduced response time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1715-1724
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• 2013

The maximum lifetime data aggregation problem is to maximize the network lifetime as minimizing the transmission energy of all deployed nodes in wireless sensor networks. In this paper, we propose a simulated annealing algorithm to solve efficiently the maximum lifetime data aggregation problem on the basis of meta-heuristic approach in wireless sensor networks. In order to make a search more efficient, we propose a novel neighborhood generating method and a repair function of the proposed algorithm. We compare the performance of the proposed algorithm with other existing algorithms through some experiments in terms of the network lifetime and algorithm computation time. Experimental results show that the proposed algorithm is efficient for the maximum lifetime data aggregation problem in wireless sensor networks.

• Journal of KIISE:Software and Applications
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• v.32 no.11
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• pp.1084-1098
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• 2005

In this paper, we propose a migration technique for autonomous mobile agents suitable to dynamic environments. The proposed migration technique dynamically creates the itinerary of agents that considers states of networks and systems. In the migration of the agent, it first sends prefetching message to the next system. The system receives necessary data for migration in advance. Through this, we reduce the amount of the sending data and save the time for creating the instance of the agent. And it improves the execution efficiency by using the checkpoint-based recovery method that does not execute the agent again and recovers the process states even though the errors take place. To show superiority of the proposed technique, we compare the proposed method with the existing methods through various simulations.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11
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• pp.3500-3508
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• 2000

In is proposed that the algorithm for self-healing to restoration the backup-VP occurrence error in ATM network. Backup-VP used method is one of the most used algorithm. Most of the problem of backup-VP used algorithm occurts heavily when backup-VP is fault new algorithm is proposed to repair this problem which senup secondary backup-VP. The sccondary gackup-VP algorithm has many disadvantages in mitial setup. That is it requires too manyy calculation. To setile preseribed problem, this thesis proose quality of serviec algorithm to propose of the present problem. Analysis is adopted.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.142-145
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• 2001

I did research or design technology of(integration) network of PSTN and PSDN in this paper. Network structure model in association with soft switching and access gateway can create various services based on web and live time and service fee at the rate of bandwidth which can't be provided by existing network based on SONET. Also, interns of capability(function) of each area and construction of local network subscribers, it has great recovery capability by separating each network as local areas. It indicates that it can additionally maximize the application of its own communication network and drastic reduction of communication cost because it is alternated to exclusive usage cost.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.381-386
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• 2008

본 연구에서는 현장 조사를 통해 얻어지는 피해정보를 광역적 무선통신을 이용해 전송하고 웹GIS의 지도상에 실시간으로 업데이트하여 보다 신속하고 효율적으로 관련 정보를 제공하는 실시간 피해정보제공시스템을 개하였다. 연구 대상지역은 매년 대형 태풍과 집중호우로 인한 피해가 발생하고 있는 부산시 강서구를 선정하였다. 도형 데이터베이스는 대상지역 $179.05km^2$에 대하여 1:5,000 및 1:1,000 수치지도를 기반으로 행정경계 등 7개의 주제도로 구축하였다. 또한, IKONOS위성의 1m급 고해상도 위성영상을 스트리밍 방식으로 구축하여 실제 피해현장과 주변 환경에 관한 정보들을 함께 제공할 수 있는 방안을 연구하였다. 웹GIS 시스템의 웹 프레임은 HTML과 ASP언어를 이용하여 개발되었으며, 맵 서비스 프레임은 ArcIMS를 이용하여 개발되었다. 현장에서 조사된 피해정보는 좌표를 기반으로 하여 웹GIS 시스템에 점으로 표출되며 재해대장 웹 페이지를 통해 피해지역의 영상 및 피해추정액등 세부적인 피해정보를 함께 제공하도록 하였다. 웹GIS 시스템은 피해현황을 GIS 데이터와 함께 실시간으로 제공함으로써 신속한 현장파악, 대응책 마련 및 복구계획 수립을 위한 의사결정에 활용 가능할 것이라 예상되며, 소방방재청에서 구축하고 있는 NDMS와 연계를 통하여 여러 국가기관에서 얻어지는 다양한 피해정보의 제공 또한 가능할 것이라 사료된다.