Browsing by Author "Su, Chun-Hsien"

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Developing a VM-based Hybrid DNS System with High Availability
(2013)
Chen, Chang-Sheng
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Su, Chun-Hsien
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資訊技術服務中心
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Information Technology Services Center
In this paper, we proposed to develop a set of lowcost, virtual machine-based hybrid DNS scheme (i.e., a frontend + multiple backend systems) with a scalable capability to provide DNS services with high availability. In this study, we had built two use case diagrams, namely the frontend (i.e., load-balancer) and the backend (i.e., DNS resolving) subsystems, for modeling the overall system. Moreover, we had developed a two-phase DNS health checking algorithm and designed two testing cases to help implement and evaluate the system. For validating the hybrid scheme, we had deployed and run the proposed DNS system for more than 2 years on our campus network. Based on the collected statistics, we had ensured that the proposed DNS systems could offer the expected DNS services with load-sharing capability and high availability for serving daily DNS queries on a regular basis and run smoothly.
Exploring the correlation between P2P Applications and Network Architecture
(2009)
Chen, Chang-Sheng
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Liu, Ta-Chung
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Su, Chun-Hsien
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交大名義發表
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National Chiao Tung University
Nowadays, P2P applications dominate most of the network traffic and the access pattern poses a serious problem. While some P2P connections are formed within an ISP (or organization), most P2P connections are connected to the rest of the internet, at a high cost to the site. In this paper, we would like to study the topic on how different network architectures (i.e., asymmetric vs. symmetric network) influence the network traffic and the user behaviors with the peer-to-peer (P2P) applications. Many mechanisms could be adopted for improving the network performance of the site.
Fabrication of Multicomponent Polymer Nanostructures Containing PMMA Shells and Encapsulated PS Nanospheres in the Nanopores of Anodic Aluminum Oxide Templates
(2015-03-01)
Ko, Hao-Wen
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Chi, Mu-Huan
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Chang, Chun-Wei
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Su, Chun-Hsien
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Wei, Tzu-Hui
Multi-component polymer nanomaterials have attracted great attention because of their applications in areas such as biomedicine, tissue engineering, and organic solar cells. The precise control over the morphologies of multi-component polymer nanomaterials, however, is still a great challenge. In this work, the fabrication of poly(methyl methacrylate)(PMMA)/polystyrene (PS) nanostructures that contain PMMA shells and encapsulated PS nanospheres is studied. The nanostructures are prepared using a triple solution wetting method with anodic aluminum oxide (AAO) templates. The nanopores of the templates are wetted sequentially by PS solutions in dimethylformamide (DMF), PMMA solutions in acetic acid, and water. The compositions and morphologies of the nanostructures are controlled by the interactions between the polymers, solvents, and AAO walls. This work not only presents a feasible method to prepare multi-component polymer nanomaterials, but also leads to a better understanding of polymer-solvent interactions in confined geometries.
Hybrid Titania Photoanodes with a Nanostructured Multi-Layer Configuration for Highly Efficient Dye-Sensitized Solar Cells
(2013-05-02)
Wu, Hui-Ping
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Lan, Chi-Ming
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Hu, Jyun-Yu
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Huang, Wei-Kai
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Shiu, Jia-Wei
To construct a hybrid titania photoanode containing nanoparticles and nanorods of varied size in a multilayer (ML) configuration for dye-sensitized solar cells, the essence of our ML design is a bilayer system with additional layers of nanorods of well-controlled size inserted between the transparent and the scattering layers to enhance the light harvesting capability for photosensitizers with small absorptivity, such as Z907. We measured charge-extraction and intensity-modulated photoelectric spectra to show the advantages of one-dimensional nanorods with an improved electron-transport property and an upward shift of the potential band edge; a favorable ML configuration was constructed to have a cascade potential feature for feasible electron transport from long nanorods, to normal nanorods, to small nanoparticles. On the basis of the ML system reported herein, we demonstrate how the performance of a Z907 device is improved to attain eta similar to 10%, which is a milestone for its future commercialization.
Shaping the Light: The Key Factors Affecting the Photophysical Properties of Fluorescent Polymer Nanostructures
(2016-12)
Chi, Mu-Huan
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Su, Chun-Hsien
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Cheng, Ming-Hsiang
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Chung, Pei-Yun
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Peng, Chi-How
To manipulate the functions of nanomaterials more precisely for diverse applications, the controllability and critical influencing factors of their properties must be thoroughly investigated. In this work, the macroscopic and microscopic effects are studied on the photophysical properties of various pyrene-ended poly(styrene-block-methyl methacrylate) nanostructures. Fluorescent polymer nanospheres, nanorods, and nanotubes are prepared by different template-based methods using anodic aluminum oxide membranes. Chain arrangements and conformations are determined as the key factors affecting the photophysical properties of the fluorescent polymer nanostructures. This work not only gives a deeper understanding of the effects on the photophysical properties of polymer nanomaterials influenced by morphologies, chain arrangements, and chain conformations, but also provides a reference for designing proper fluorescent nanostructures for specific applications.
Solvent-Induced Dewetting on Curved Substrates: Fabrication of Porous Polymer Nanotubes by Anodic Aluminum Oxide Templates
(2015-09-08)
Chi, Mu-Huan
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Chang, Chun-Wei
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Ko, Hao-Wen
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Su, Chun-Hsien
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Lee, Chih-Wei
Dewetting of polymer thin films triggered by thermal or solvent annealing on flat substrates have been widely studied. Research on dewetting of polymer thin films on curved substrate, however, has been rarely investigated and remains a great challenge, especially for dewetting induced by solvent annealing. In this work, we study the dewetting of polymer thin films on curved substrates by annealing poly(methyl methacrylate) (PMMA) nanotubes in cylindrical nanopores of anodic aluminum oxide (AAO) templates via dimethylformamide (DMF) vapor treatment. After solvent annealing, dewetting of the curved PMMA thin films is induced, resulting in the formation of porous PMMA nanotubes. By changing the experimental conditions such as annealing time, solvent quality, and molecular weight of polymer, the hole sizes of the PMMA nanotubes can be controlled or even prevented. To demonstrate the universality of this method, porous nanotubes of polystyrene (PS) and fluorescent pyrene-ended PMMA (Py-PMMA) are also fabricated. This work not only provides a better understanding of dewetting of polymer thin films on curved substrates but also offers a promising new way to prepare porous polymer nanotubes with controllable hole sizes.