• Title/Summary/Keyword: 2-mode 네트워크

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Prevention Scheme of DDoS Attack in Mobile WiMAX Networks Using Shared Authentication Information (Mobile WiMAX 네트워크에서 공유 인증 정보를 이용한 분산 서비스 거부 공격 방어)

  • Kim, Young-Wook;Bahk, Sae-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.2B
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    • pp.162-169
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    • 2009
  • Message Authentication Code (MAC) assures integrity of messages. In Mobile WiMAX, 128-bit Cipher-based MAC (CMAC) is calculated for management messages but only the least significant half is actually used truncating the most significant 64 bits. Naming these unused most significant 64bits Shared Authentication Information (SAI), we suggest that SAI can be applied to protect the network from DDoS attack which exploits idle mode vulnerabilities. Since SAI is the unused half of CMAC, it is as secure as 64bits of CMAC and no additional calculations are needed to obtain it. Moreover, SAI doesn't have to be exchanged through air interface and shared only among MS, BS, and ASN Gateway. With these good properties, SAI can efficiently reduce the overheads of BS and ASN GW under the DDoS attack.

A Coordinator-based RFID Protocol to Avoid Reader Collision (코디네이터 기반 RFID 리더 충돌 회피 프로토콜)

  • Yang, Hoon-Gee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.2
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    • pp.321-328
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    • 2010
  • This paper presents a coordinator-based TDMA reader protocol that can avoid the reader collision in a passive RFID system. In the proposed protocol, the coordinator can not only minimize the number of empty slots by efficiently allocating slots to readers incoming in Poisson distribution, but reduce latency time through the limited frame size. The proposed protocol can be implemented in either mobile or fixed mode through the slot structure to be described in the context. The simulation results show it works as suggested and the frame size limitation as well as the statistical distribution of incoming readers has a great impact on the overall slots and the average latency time.

Software ATM Switch Server for ATM Adaptation Layer Type 2 (ATM Adaptation Layer Type 2 스위칭을 위한 소프트웨어 스위치 서버 구현)

  • 신동훈;김태석;권택근
    • Proceedings of the Korean Information Science Society Conference
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    • 2000.10c
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    • pp.180-182
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    • 2000
  • 기존의 ATM(Asynchronous Transfer Mode) 스위치는 하나의 셀 안에 하나의 음성 데이터를 전송하는 방식이었다. 이러한 방식으로는 적은 양을 갖는 실시간 가변 비트율의 음성 데이터의 서비스를 제공하기에는 비효율적이었다. 이에 ATM 네트워크에서 사용자에게 실시간 가변 비트율로, 적은 양의 음성 데이터를 멀티플랙싱하여 하나의 ATM 셀의 유료부하에 실어 보내는 방식인 AAL2(ATM Adaptation Layer Type 2) 프로토콜의 표준화가 이루어졌다. AAL2 스위치 서버는 AAL2 프로토콜로 인코딩된 ATM 셀을 스위칭하기 위해서 개발되었다. AAL2 스위치 서버는 CPS(Common Part Sublayer) 패킷을 추출해내는 부분과 CPS 패킷의 식별자를 갖고 식별자 스위칭하는 부분, 그리고 스위칭이 끝난 식별자를 갖는 CPS 패킷을 ATM 셀로 만들어 ATM 네트워크를 통해서 전송하는 부분으로 나뉜다. AAL2 스위치 서버를 3개의 부분으로 나누는 이유는 셀을 전송받는 부분과, 식별자 스위칭하는 부분, 다시 셀을 전송하는 부분으로 나누어 병렬 처리를 함으로써 스위치의 성능을 향상시킨다. 이 논문에서는 AAL2 스위치 서버를 구현하고, 그 활용방안에 대해서 알아보도록 한다.

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User-Perspective Issue Clustering Using Multi-Layered Two-Mode Network Analysis (다계층 이원 네트워크를 활용한 사용자 관점의 이슈 클러스터링)

  • Kim, Jieun;Kim, Namgyu;Cho, Yoonho
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.93-107
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    • 2014
  • In this paper, we report what we have observed with regard to user-perspective issue clustering based on multi-layered two-mode network analysis. This work is significant in the context of data collection by companies about customer needs. Most companies have failed to uncover such needs for products or services properly in terms of demographic data such as age, income levels, and purchase history. Because of excessive reliance on limited internal data, most recommendation systems do not provide decision makers with appropriate business information for current business circumstances. However, part of the problem is the increasing regulation of personal data gathering and privacy. This makes demographic or transaction data collection more difficult, and is a significant hurdle for traditional recommendation approaches because these systems demand a great deal of personal data or transaction logs. Our motivation for presenting this paper to academia is our strong belief, and evidence, that most customers' requirements for products can be effectively and efficiently analyzed from unstructured textual data such as Internet news text. In order to derive users' requirements from textual data obtained online, the proposed approach in this paper attempts to construct double two-mode networks, such as a user-news network and news-issue network, and to integrate these into one quasi-network as the input for issue clustering. One of the contributions of this research is the development of a methodology utilizing enormous amounts of unstructured textual data for user-oriented issue clustering by leveraging existing text mining and social network analysis. In order to build multi-layered two-mode networks of news logs, we need some tools such as text mining and topic analysis. We used not only SAS Enterprise Miner 12.1, which provides a text miner module and cluster module for textual data analysis, but also NetMiner 4 for network visualization and analysis. Our approach for user-perspective issue clustering is composed of six main phases: crawling, topic analysis, access pattern analysis, network merging, network conversion, and clustering. In the first phase, we collect visit logs for news sites by crawler. After gathering unstructured news article data, the topic analysis phase extracts issues from each news article in order to build an article-news network. For simplicity, 100 topics are extracted from 13,652 articles. In the third phase, a user-article network is constructed with access patterns derived from web transaction logs. The double two-mode networks are then merged into a quasi-network of user-issue. Finally, in the user-oriented issue-clustering phase, we classify issues through structural equivalence, and compare these with the clustering results from statistical tools and network analysis. An experiment with a large dataset was performed to build a multi-layer two-mode network. After that, we compared the results of issue clustering from SAS with that of network analysis. The experimental dataset was from a web site ranking site, and the biggest portal site in Korea. The sample dataset contains 150 million transaction logs and 13,652 news articles of 5,000 panels over one year. User-article and article-issue networks are constructed and merged into a user-issue quasi-network using Netminer. Our issue-clustering results applied the Partitioning Around Medoids (PAM) algorithm and Multidimensional Scaling (MDS), and are consistent with the results from SAS clustering. In spite of extensive efforts to provide user information with recommendation systems, most projects are successful only when companies have sufficient data about users and transactions. Our proposed methodology, user-perspective issue clustering, can provide practical support to decision-making in companies because it enhances user-related data from unstructured textual data. To overcome the problem of insufficient data from traditional approaches, our methodology infers customers' real interests by utilizing web transaction logs. In addition, we suggest topic analysis and issue clustering as a practical means of issue identification.

MODE : Managed Objects(MOs) Development Environment for TMN-based ATM Network Management (MODE :TMN 체계의 ATM 망 관리를 위한 관리 객체 개발 환경)

  • Gang, Won-Seok;Kim, Gi-Hyeong;Kim, Yeong-Tak
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.2
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    • pp.415-424
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    • 1999
  • Systematic telecommunication network management is essential for operating large-scale integrated networks which consist of various network components manufactured by different vendors. ISO and ITU-T recommend the CMIP-based TMN architecture for this purpose. TMN uses GDMO for the definition of managed objects, and various GDMO compilers have been developed. However, the development of management objects by using these compilers is still a difficult task. In this paper, we present a GUI-based managed objects development environment, MODE. MODE divides managed object codes by system independent code(SIC) and system dependent cede(SDC). By providing development environments for SIC and SDC, MODE can ease the development of managed objects. To show the efficiency of MODE, we develop the managed objects of an ATM switch in MODE.

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Experiments on An Network Processor-based Intrusion Detection (네트워크 프로세서 기반의 침입탐지 시스템 구현)

  • Kim, Hyeong-Ju;Kim, Ik-Kyun;Park, Dae-Chul
    • The KIPS Transactions:PartC
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    • v.11C no.3
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    • pp.319-326
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    • 2004
  • To help network intrusion detection systems(NIDSs) keep up with the demands of today's networks, that we the increasing network throughput and amount of attacks, a radical new approach in hardware and software system architecture is required. In this paper, we propose a Network Processor(NP) based In-Line mode NIDS that supports the packet payload inspection detecting the malicious behaviors, as well as the packet filtering and the traffic metering. In particular, we separate the filtering and metering functions from the deep packet inspection function using two-level searching scheme, thus the complicated and time-consuming operation of the deep packet inspection function does not hinder or flop the basic operations of the In-line mode system. From a proto-type NP-based NIDS implemented at a PC platform with an x86 processor running Linux, two Gigabit Ethernet ports, and 2.5Gbps Agere PayloadPlus(APP) NP solution, the experiment results show that our proposed scheme can reliably filter and meter the full traffic of two gigabit ports at the first level even though it can inspect the packet payload up to 320 Mbps in real-time at the second level, which can be compared to the performance of general-purpose processor based Inspection. However, the simulation results show that the deep packet searching is also possible up to 2Gbps in wire speed when we adopt 10Gbps APP solution.

Acoustic Field Analysis using 1D Network Model in an Aero Gas Turbine Combustor (1D 네트워크 모델을 이용한 항공용 가스터빈 연소기에서의 음향장 해석)

  • Pyo, Yeongmin;Park, Heeho;Jung, Seungchai;Kim, Daesik
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.2
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    • pp.38-45
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    • 2019
  • The present work suggests a numerical approach using a thermoacoustic network model for the eigenvalue calculation of thermoacoustic instability problems in an aero gas turbine combustor. The model is developed based on the conservation laws for mass, momentum, and energy between acoustic network elements with an area change. Acoustic field in a practical aero gas turbine combustor which has a complicated flow path is analyzed using the current model. The predictive capabilities of the current modeling approach are compared with the acoustic characteristics calculated using Helmholtz solver based on 3D finite element method(FEM).

Throughput Analysis of Non-Transparent Mode in IEEE 802.16j Mobile Multi-Hop Relay Networks (IEEE 802.16j MMR 네트워크에서 Non-Transparent 중계모드의 전송률 분석)

  • Lee, Ju-Ho;Lee, Goo-Yeon;Jeong, Choong-Kyo
    • Journal of the Korea Society for Simulation
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    • v.21 no.2
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    • pp.51-58
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    • 2012
  • In IEEE 802.16j MMR protocol, two modes about usage of RS are proposed; one is transparent mode to enhance data throughput and the other is non-transparent mode to extend coverage. In this paper, we focus on non-transparent mode and find that the mode can also improve data throughput. Therefore, we analyze data throughput on various RS topology and their extended coverage area by simulation in IEEE 802.16j non-transparent mode. We also compare the simulation results with the single MR-BS system of which coverage is extended by higher transmission power. From the comparisons of simulation results, we see that higher throughput can be obtained in the proposed non-transparent mode.

Transmission Performance Analysis for cipher communication in aerial tactical communication link (항공전술 통신링크에서 암호통신을 위한 전송성능 분석)

  • Hong, Jin-Keun;Park, Sun-Chun;Kim, Seng-Jo;Park, Jong-Wook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.4
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    • pp.63-70
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    • 2005
  • LINK16 is a system which is designed to maximize performance in a particular tactical environment with high levels of jamming. In this paper, transmission performance of synchronization pattern for cipher communication in aerial tactical communication link is presented. Transmission architecture of operating mode (standard DP, P2SP, P2DP, P4mode) in LINK16 network is discussed, and an effect of synchronization pattern, a quality of degraded effect of transmission communication for collision probability between hopping frequencies and fading channel in crypto communication is analyzed.

Exploring Research Trends in Curriculum through Keyword Network Analysis (키워드 네트워크 분석을 통한 교육과정 연구 동향 탐색)

  • Jang, Bong Seok
    • Journal of Industrial Convergence
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    • v.18 no.2
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    • pp.45-50
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    • 2020
  • The purpose of this study is to analyze relationships among essential keywords in curriculum. The number of 1,935 keyword was collected from 644 manuscripts published between 2002 and 2019. For data analysis, this study selected softwares of KrKwic and KrTitle to compose a 1-mode network matrix and UCINET 6 and NetDraw to implement network analysis and visualization. Results are as follows. First, the frequency of keyword was curriculum, curriculum development, national curriculum, competency-based curriculum, 2015 revised national curriculum, curriculum implementation, understanding by design, competency, teacher education, school curriculum, and IBDP from highest to lowest. Second, degree centrality was curriculum development, curriculum, competency-based curriculum, national curriculum, 2015 revised national curriculum, understanding by design, competency, key competency, high school curriculum, textbook, curriculum implementation, teacher education, and IBDP from highest to lowest.