Browsing by Author "Yeh, Chih-Hung"

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An Extended SDN Architecture for Network Function Virtualization with a Case Study on Intrusion Prevention
(2015-05-01)
Lin, Ying-Dar
;
Lin, Po-Ching
;
Yeh, Chih-Hung
;
Wang, Yao-Chun
;
Lai, Yuan-Cheng
In conventional software-defined networking (SDN), a controller classifies the traffic redirected from a switch to determine the path to network function virtualization (NFV) modules. The redirection generates a large volume of control-plane traffic. We propose an extended SDN architecture to reduce the traffic overhead to the controller for providing NFV. The extension includes two-layer traffic classification in the data plane, extended OpenFlow protocol messages and service chaining mechanisms. Network events are analyzed in the data plane instead of the control plane. The efficiency is evaluated with a case study of intrusion prevention. The evaluation shows that only 0.12 percent of the input traffic is handled by the controller, while 77.23 percent is handled on the controller in conventional SDN.
Cost-Effective and Self-Textured Gallium-Doped Zinc Oxide Front Contacts for Hydrogenated Amorphous Silicon Thin-Film Solar Cells
(2013-02-01)
Yu, Shu-Hung
;
Ho, Po-Ching
;
Lee, Chia-Ling
;
Bi, Chien-Chung
;
Yeh, Chih-Hung
We adopt a economical and original method to fabricate self-textured gallium-doped zinc oxide (GZO) front contacts for hydrogenated amorphous silicon (a-Si: H) single-junction solar cells. This technique involves an atmospheric-pressure plasma jet (APPJ) and a dc sputtering process. The electro-optical characteristics of the textured GZO films are mainly controlled by the haze of organosilicon underlayers deposited by the APPJ. The films exhibit an average optical transmittance of about 80% and resistivity below 9.91 x 10(-4) Omega cm. Moreover, compared with flat solar cells, textured cells fabricated on moderate GZO front contacts show 7.9 and 10.9% enhancements in conversion efficiency and short-circuit current density, respectively. (C) 2013 The Japan Society of Applied Physics
Double-Pattern Textured ZnO:Ga Thin Films Fabricated by an APPJ and an DC Sputtering
(2012)
Yu, Shu-Hung
;
Ho, Po-Ching
;
Yang, Teng-Wei
;
Bi, Chien-Chung
;
Yeh, Chih-Hung
Here, double-pattern textured gallium doped zinc oxide (GZO) films were achieved by inserting organosilicon underlayers deposited from an atmospheric pressure plasma jet (APPJ) between sputtered GZO films and glass substrates. The electro-optical characteristics of the textured GZO films were controlled by the haze of organosilicon underlayers. All GZO films were thermally annealed in high vacuum to improve film quality. Post-annealed textured GZO films exhibited an average optical transmittance of about 80% in a wide range. Hall measurements showed Hall mobility above 26 cm(2)/V-s, carrier concentration around 2.4 x 10(20) cm(-3) and resistivity below 9.91 x 10(-4) Omega-cm. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.003203ssl] All rights reserved.