Browsing by Author "Chen, Yi-Ren"

Now showing 1 - 7 of 7

Detecting Amplification Attacks with Software Defined Networking
(2017-01-01)
Chen, Chih-Chieh
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Chen, Yi-Ren
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Lu, Wei-Chih
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Tsai, Shi-Chun
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Yang, Ming-Chuan
Distributed denial of service (DDoS) is an attack that attempts to disrupt network service for various malicious purposes. It makes use of public services as reflectors to amplify the traffic, and thus called distributed reflection denial of service attacks. This type of attack forges source IP address, and makes it hard to filter the problematic packets. With Software Defined Networking (SDN) and machine learning techniques, we implement a system to detect DRDoS packets and block the amplification attacks automatically. DNS and NTP amplifications are two typical attacks of DDoS. By analyzing the traffic features, although our classifier is trained only for the DNS amplification attack, our system can identify and then block both DNS and NTP amplification attacks with great accuracy.
Detecting P2P Botnet in Software Defined Networks
(2018-01-01)
Su, Shang-Chiuan
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Chen, Yi-Ren
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Tsai, Shi-Chun
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Lin, Yi-Bing
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資訊工程學系
Software Defined Network separates the control plane from network equipment and has great advantage in network management as compared with traditional approaches. With this paradigm, the security issues persist to exist and could become even worse because of the flexibility on handling the packets. In this paper we propose an effective framework by integrating SDN and machine learning to detect and categorize P2P network traffics. This work provides experimental evidence showing that our approach can automatically analyze network traffic and flexibly change flow entries in OpenFlow switches through the SDN controller. This can effectively help the network administrators manage related security problems.
Developing a Phase and Intensity Measurement Technique with Multiple Incident Angles under Surface Plasmon Resonance Condition
(2013-01-01)
Han, Chien-Yuan
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You, Du Cheng
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Chen, Yi-Ren
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Chao, Yu-Faye
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光電工程學系
This work presents the application of a focused beam polarizer-sample-analyzer imaging ellipsometer in measuring the ellipsometric parameters under the surface plasmon resonance condition. By using a cylindrical lens to produce fan shaped beam with multiple incident angles, three-intensity measurement technique can measure the ellipsometric parameters against each incidence but without the need of calibrating the azimuth errors of polarizer and analyzer. As a result of multiple incident angles approach, the whole SPR curve can be obtained without rotating the sensor chip. The intensity and phase response in the air and water interface of the sensor chip were demonstrated, and almost all measured results are close to the theoretical model.
Forwarding Path Discovery with Software Defined Networking
(2017-01-01)
Chen, Chih-Chieh
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Chen, Yi-Ren
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Tsai, Shi-Chun
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Yang, Ming-Chuan
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資訊工程學系
Without STP and LLDP, we propose a new approach to find faster paths between the source and the destination and fully utilize the links between switches under the Software Defined Network paradigm. To find round-trip path with lighter load, we design a mechanism to compose special ARP packets for exploring the routing path and avoid broadcast storm by dropping late or duplicate packets. Meanwhile, the controller can carefully regulate other packets without affecting the behavior of the special packets. The evaluation results with the Clos-like network topology show that our approach can be used to improve the performance of transmission throughput. We believe our method is very suitable, especially, for a dynamic network environment, where links are up and down frequently. Our implementation can be seen as an instance showing the flexibility of SDN.
Histone Demethylase RBP2 Promotes Lung Tumorigenesis and Cancer Metastasis
(2013-08-01)
Teng, Yu-Ching
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Lee, Cheng-Feng
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Li, Ying-Shiuan
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Chen, Yi-Ren
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Hsiao, Pei-Wen
The retinoblastoma binding protein RBP2 (KDM5A) is a histone demethylase that promotes gastric cancer cell growth and is enriched in drug-resistant lung cancer cells. In tumor-prone mice lacking the tumor suppressor gene RB or MEN1, genetic ablation of RBP2 can suppress tumor initiation, but the pathogenic breadth and mechanistic aspects of this effect relative to human tumors have not been defined. Here, we approached this question in the context of lung cancer. RBP2 was overexpressed in human lung cancer tissues where its depletion impaired cell proliferation, motility, migration, invasion, and metastasis. RBP2 oncogenicity relied on its demethylase and DNA-binding activities. RBP2 upregulated expression of cyclins D1 and E1 while suppressing the expression of cyclin-dependent kinase inhibitor p27 (CDKN1B), each contributing to RBP2-mediated cell proliferation. Expression microarray analyses revealed that RBP2 promoted expression of integrin-beta 1 (ITGB1), which is implicated in lung cancer metastasis. Mechanistic investigations established that RBP2 bound directly to the p27, cyclin D1, and ITGB1 promoters and that exogenous expression of cyclin D1, cyclin E1, or ITGB1 was sufficient to rescue proliferation or migration/invasion, respectively. Taken together, our results establish an oncogenic role for RBP2 in lung tumorigenesis and progression and uncover novel RBP2 targets mediating this role. (C)2013 AACR.
TET1 Suppresses Cancer Invasion by Activating the Tissue Inhibitors of Metalloproteinases
(2012-09-01)
Hsu, Chih-Hung
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Peng, Kai-Lin
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Kang, Ming-Lun
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Chen, Yi-Ren
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Yang, Yu-Chih
Tumor suppressor gene silencing through cytosine methylation contributes to cancer formation. Whether DNA demethylation enzymes counteract this oncogenic effect is unknown. Here, we show that TET1, a dioxygenase involved in cytosine demethylation, is downregulated in prostate and breast cancer tissues. TET1 depletion facilitates cell invasion, tumor growth, and cancer metastasis in prostate xenograft models and correlates with poor survival rates in breast cancer patients. Consistently, enforced expression of TET1 reduces cell invasion and breast xenograft tumor formation. Mechanistically, TET1 suppresses cell invasion through its dioxygenase and DNA binding activities. Furthermore, TET1 maintains the expression of tissue inhibitors of metalloproteinase (TIMP) family proteins 2 and 3 by inhibiting their DNA methylation. Concurrent low expression of TET1 and TIMP2 or TIMP3 correlates with advanced node status in clinical samples. Together, these results illustrate a mechanism by which TET1 suppresses tumor development and invasion partly through downregulation of critical gene methylation.
Thermoelectric Efficiency in Nanojunctions: A Comparison between Atomic Junctions and Molecular Junctions
(2009-11-01)
Liu, Yu-Shen
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Chen, Yi-Ren
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Chen, Yu-Chang
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電子物理學系
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Department of Electrophysics
Using first-principles approaches, we investigate the thermoelectric efficiency, characterized by the figure of merit ZT, in metallic atomic junctions and insulating molecular junctions. To gain insight into the properties of ZT, an analytical theory is also developed to study the dependence of ZT on lengths (l) and temperatures (T). The theory considers the combined heat current carried by electrons and phonons. We observe a characteristic temperature: T(0) = (beta/gamma(l))(1/2). When T << T(0), the electronic heat current dominates the combined heat current and ZT proportional to T(2). When T >> T(0), the phononic heat current dominates the combined heat current and ZT tends to a saturation value. Moreover, the metallic atomic junctions and the insulating molecular junctions have opposite trend for the dependence of ZT on lengths, that is, ZT increases as the length increases for aluminum atomic junctions, while ZT decreases as the length increases for alkanethiol molecular junctions.