• Title/Summary/Keyword: Chang's Method

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Prevention of DDoS Attacks for Enterprise Network Based on Traceback and Network Traffic Analysis

  • Ma, Yun-Ji;Baek, Hyun-Chul;Kim, Chang-Geun;Kim, Sang-Bok
    • Journal of information and communication convergence engineering
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    • v.7 no.2
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    • pp.157-163
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    • 2009
  • With the wide usage of internet in many fields, networks are being exposed to many security threats, such as DDoS attack and worm/virus. For enterprise network, prevention failure of network security causes the revealing of commercial information or interruption of network services. In this paper, we propose a method of prevention of DDoS attacks for enterprise network based on traceback and network traffic analysis. The model of traceback implements the detection of IP spoofing attacks by the cooperation of trusted adjacent host, and the method of network traffic analysis implements the detection of DDoS attacks by analyzing the traffic characteristic. Moreover, we present the result of the experiments, and compare the method with other methods. The result demonstrates that the method can effectively detect and block DDoS attacks and IP spoofing attacks.

Suppression of bridge flutter by passive aerodynamic control method (교량 플러터의 공기역학적 수동제어)

  • Kwon S.-D.;Jung S.;Chang S.-P.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.435-438
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    • 2002
  • In this study, a new passive aerodynamic control method is proposed. Control plate which is oscillated by TMD-like mechanism makes flutter stabilizing airflow. Effectiveness of proposed model is verified by experimental and analytical study. In addition, various parameters of the proposed system are investigated. Applicability to long span bridge is also examined. According to the research results, proposed model is very effective in suppressing flutter, and it also shows remarkable robustness.

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The Analysis of the S-DMB Performance using Hierarchical 16APSK Modulation Scheme (계층적 16APSK 변조 기법을 이용한 S-DMB 성능 분석)

  • Lee, In-Ki;Chang, Dae-Ig
    • Proceedings of the IEEK Conference
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    • 2007.07a
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    • pp.175-176
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    • 2007
  • In this paper, we introduce Satellite Digital Multimedia Broadcasting(S-DMB) system and show the method increasing the channel capacity. To reduce the burden that has to change the existing system, the system has to be offered the Backward-compatibility. This paper show the method using hierarchical 16APSK modulation. And to obtain the reasonable BER performance between existing path(we call high priority) and additional path(we call low priority).

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A Study on the Disbonding Detection of Al/Al Honeycomb Sandwich Structures by Ultrasonic Methods (초음파를 이용한 Al/Al 하니캄 구조물의 Disbonding 검출에 관한 연구)

  • Cho, K.S.;Lee, J.S.;Chang, H.K.;Lee, S.H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.10 no.1
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    • pp.29-37
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    • 1990
  • In this study the disbonding tests of adhesively bonded Al/Al honeycomb structures were performed by ultrasonic methods. Ultrasonic C-scan squiter method and ultrasonic surface wave attenuation measuring method were applied for the detection of skin/core disbonding. The bonding quality of Al/Al honeycomb structures could be well evaluated by properly controlled ultrasonic parameters.

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A Study on an Independent 6WD/6WS of Electric Vehicle using Optimum Tire Force Distribution (최적 타이어 힘 분배 방법을 통한 전기차의 독립 6WD/6WS에 관한 연구)

  • Kim, Dong-Hyung;Kim, Chang-Jun;Kim, Young-Ryul;Han, Chang-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.7
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    • pp.632-638
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    • 2010
  • This paper presents an optimum tire force distribution method for 6WD/6WS(6-Wheel-Drive and 6-Wheel-Steering) electric vehicles. Using an independent steering and driving system, the performance of 6WD/6WS vehicles can be improved, as, for example, with respect to their maneuverability under low speed and their stability at high speed. Therefore, there should be a control strategy for finding the optimum tire forces that satisfy the driver's command and minimize energy consumption. From the driver's commands (steering angle and accelerator/brake pedal stroke), the desired yaw moment, the desired lateral force, and the desired longitudinal force were obtained. These three values were distributed to each wheel as the torque and the steering angle, based on the optimum tire force distribution method. The optimum tire force distribution method finds the longitudinal/lateral tire forces of each wheel that minimize the cost function, which is the sum of the normalized tire forces. Next, the longitudinal/lateral tire forces of each wheel are converted into the reference torque inputs and the steering wheel angle inputs. The proposed method was tested through a simulation, and its effectiveness was verified.

Analysis of the DNA Fingerprints from the Teeth -Using Chelex$^\textregistered$ 100 as a Medium of Simple Extraction of DNA from the Teeth- (치아에서의 DNA 유전자지문 분석 -Chelex$^\textregistered$ 100을 매개체로 한 DNA추출-)

  • Chang-Lyuk Yoon
    • Journal of Oral Medicine and Pain
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    • v.20 no.2
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    • pp.515-528
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    • 1995
  • The human genomic deoxyribonucleic acid(DNA) was extracted from the pulp, dentin of 22 teeth by clelex, phenol methods. Samples of the tooth-derived DNA were amplified by polymerase chain reaction(PCR), electrophosed for sex determination by detection of X-Y homologus amelogenin gene and D1S80 locus detection The following results have been achieved. 1. Chelex and phenol method are effective to sex determination in the pulp and dentin 2. Chelex method is not suitable for detection of D1S80 locus. 3. Concentration and purity of DNA for teeth using chelex method is lower than using phenol method. From the above investigation, chelex method is simple, rapid for sex determination, but it is not suitable for detection of VNTRs.

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Based on the Demand, A Scheduling Method for the Seoul-Busan High Speed Rail (수요기반의 경부고속철도 열차운행계획 수립기법에 관한 연구)

  • Park, Jin-Yong;Chang, Justin S.
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.380-388
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    • 2010
  • This paper explored an effective scheduling method for the Seoul-Busan High Speed Rail. It is important to decide train frequency influencing on scheduling method. Main factors to decide train frequency are location of station, social economic index, land use of station area and travel demand. In this paper, we focused on travel demand which is critical factor to decide train frequency. And we studied on standardized scheduling method. Simulation method is used to analyze the performance of explored method.

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