흰쥐 시상하부에서 gonadotropin-releasing hormone (GnRH)과 GnRH 수용체 유전자 발현에 대한 GnRH agonist의 억제적 조절

Thesis (master`s)--서울대학교 대학원 :분자생물학과,1997.Maste

QoS-based Subcarrier and Power allocation in User-cooperative OFDMA Systems

본 연구는 정보통신부 및 정보통신연구진흥원의 대학IT연구센터 지원사업의 연구결과로 수행되었음 (IITA-2008-(C1090-0801-0016)

OFDMA 기반 무선통신시스템에서 QoS를 고려한 무선 자원 관리에 관한 연구

학위논문(박사) - 한국과학기술원 : 산업및시스템공학과, 2009.2, [ vi, 104 p. ]Recently, an orthogonal frequency division multiple access (OFDMA), which is a multi-user version of the OFDM digital modulation scheme, has emerged as one of the prime multiple access schemes for broadband wireless networks. OFDMA can overcome frequency-selective fading and the inter-symbol interference problem. Moreover, the adaptive subcarrier allocation allows OFDMA system to achieve higher spectral efficiency by multiuser diversity. Subcarrier and power allocation plays important role to enhance the system throughput and to maintain the QoS among the users. This study mainly focuses on the radio resource allocation considering QoS for OFDMA-based wireless telecommunication systems. First, we study on satisfying actual client demand in OFDMA downlink system. Due to the limitations of wireless resources, some clients may not be able to obtain their desired throughput. To minimize conflicting client demands, we propose a goal programming technique which sets a goal for each client. As the goal is not a strict constraint, the system can allocate resources flexibly and generate feasible solutions consistently. In the proposed approach, we aim to minimize the weighted sum of client dissatisfaction and propose an efficient algorithm for real-time applications. The proposed algorithm can reduce the amount of dissatisfaction significantly, especially with a large number of users. Then, we extend our scope to a cooperative OFDMA system. Cooperative system allows single-antenna users to transmit using the antennas of other users, so that the users form a virtual antennas array. By cooperative transmission, users experiencing deep fading can transmit in association with relays and get better channel gain. We aim to evaluate the performance of user-cooperative transmission in multiuser OFDMA systems while optimally allocating bandwidth and transmission power to each source/relay. We consider the problem of minimizing the total transmission power while satisfying e...한국과학기술원 : 산업및시스템공학과

Study on factors influencing adoption of information security policies

본 연구는 정보통신부 ITRC 프로젝트에 의해서 일부 지원되었다

대규모 기간망을 위한 효율적인 침입탐지 기법에 관한 연구

학위논문(석사) - 한국과학기술원 : 산업공학과, 2004.2, [ iii, 43 p. ]To ensure network reliability and maintain network performance, an anomaly detection which detects abnormal behaviors in network traffic and manages them is needed. But current network-based IDSs mostly focus on end-to-end behavior and are barely capable of real-time traffic analysis on large-scale backbone networks at the ISP level. A simple method which focuses on a traffic property is adequate for real-time anomaly detection in Gigabits backbone network. In this paper, we propose a traffic volume-based anomaly detection methodology using a statistical approach. We claim that the anomaly detection which observes the traffic flows having same destination port can find anomalies earlier and more precisely than the method using merged traffic since anomalies may be hidden in a large amount of merged traffic. The proposed scheme uses concept of a traffic volume ratio per port which considers abnormal increases in the traffic volume at the port compared with the total traffic volume. Experimental results on real network data demonstrate that our algorithm performs well in detecting extreme changes of the traffic volume.한국과학기술원 : 산업공학과

An Intrusion Detection Method based on Bayesian Theory in Wireless Ad Hoc Networks

본 연구는 정보통신부 및 정보통신연구진흥원의 대학 IT 연구센터 지원사업의 연구결과로 수행되었

Fast Detection Scheme for Broadband Network Using Traffic Analysis

인터넷의 급속한 발달과 더불어 네트워크 환경에서의 침입은 빠르게 증가하고 있으며, 그 피해 또한 급격히 증가하고 있다. 최근의 인터넷 공격은 특정 호스트나 네트워크에 대한 피해를 초래할 뿐만 아니라, 네트워크 전반의 성능 저하를 유발한다. 기존의 침입 탐지 시스템은 각 지역망 및 특정한 대상 시스템을 보호하기 위한 솔루션들로, 기간망 수준의 실시간 공격 탐지에 적용하기 힘든 문제점을 가지고 있다. 본 논문에서는 네트워크 수준의 실시간 공격탐지를 위하여 각 포트별 트래픽을 대상으로 지수평활법을 적용하는 광대역 네트워크 침입 탐지 기법 제안하였다. 8일간의 기간망의 트래픽 데이터를 대상으로 한 실험에서, 제안한 기법은 공격으로 추정되는 급격한 트래픽의 증가를 적절히 탐지함을 보여주었다