Browsing by Author "Hwang, JS"

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Evaluation of information security related risks of an organization - The application of the multi-criteria decision-making method
(2003)
Guan, BC
;
Lo, CC
;
Wang, P
;
Hwang, JS
;
資訊管理與財務金融系註：原資管所+財金所
In the wake of the fast popularization of information and the rise of electronic commerce, information security is gaining much attention. How to perform the evaluation of the value of assets, how to perform the analysis of the risks associated with assets, and how to protect information assets from sabotage, theft and tamper are important topics in the study of the management of information security. This research addresses the aspects of confidentiality, integrity and availability of information and applies the Analytic Hierarchy Process (AHP) to consolidate expert's opinions on information risks, in order to construct an integrated framework for risk analysis. The BS7799 standard and the risk level matrix(RLM) are used accordingly to evaluate the effectiveness of and to categorize the risk management measures and to create a complete model for the assessment of information assets related risks. Finally, the research results are verified by a case study. The results can be used by organizations as references for information security planning and management process improvements.
Generally applicable self-masked dry etching technique for nanotip array fabrication
(2004-03-01)
Hsu, CH
;
Lo, HC
;
Chen, CF
;
Wu, CT
;
Hwang, JS
Well-aligned nanotip arrays were fabricated by electron cyclotron resonance (ECR) plasma process using gas mixtures of silane, methane, argon, and hydrogen. The resultant tips have nanoscale apexes (similar to1 nm) with high aspect ratios (similar to50), which were achieved by simultaneous SiC nanomask formation and dry etching during ECR plasma process. This technique was applied to a variety of substrates such as silicon, polycrystalline silicon, gallium nitride, gallium phosphide, sapphire, and aluminum, indicating its general applicability. High-resolutiontransmission electron microscopy and Auger depth profile analyses revealed that the SiC cap, with Si:C ratio of 1:1, exhibited 3C-SiC and 2H-SiC structure on Si and GaP, respectively, with heteroepitaxial relationship. This one-step self-masked dry etching technique enables the fabrication of uniform nanotip arrays on various substrates over large area at low process temperatures, thereby demonstrating a high potential for practical industrial application.
Magnetization of finite carbon nanotubes
(2005-05-01)
Chen, RB
;
Chang, CP
;
Hwang, JS
;
Chuu, DS
;
Lin, MF
Magnetoelectronic properties of finite carbon nanotubes (CNs) are studied for an arbitrary field direction. They are strongly affected by the nanotube geometry (length, radius; boundary structure), the magnitude and direction of the magnetic field, the Zeeman effect, and the temperature. Geometric structures determine electronic structures and magnetic properties, which thus leads to three types of energy gaps and induced magnetic fields. The critical angle, which corresponds to the change of magnetism, exists in armchair CNs, but not in zigzag CNs. It also depends on the length and the radius of CNs. Finite CNs are very different from infinite CNs. Zeeman splitting could induce complete energy-gap modulation, a drastic change in magnetization, and a gigantic paramagnetic response for all zigzag CNs. The predicted results are observable even at room temperature.
Reduced temperature-quenching of photoluminescence from indium nitride nanotips grown by metalorganic chemical vapor deposition
(2005-11-14)
Shi, SC
;
Chen, CF
;
Hsu, GM
;
Hwang, JS
;
Chattopadhyay, S
We report metalorganic chemical vapor deposition of indium nitride (InN) nanotips with apex angles of 10 degrees and length and base diameter of around 1 mu m and 200 nm, respectively. The structure of the hexagonal InN nanotips growing along [002] was studied by electron microscopy and x-ray diffraction, and the optical properties were studied using temperature-dependent photoluminescence (PL) measurements. A narrow emission peak with a 18 meV full width at half maximum positioned at 0.77 eV was obtained with no visible emission. A PL quenching of only 14% was observed with a temperature scan of 15-320 K. (C) 2005 American Institute of Physics.
SiC-capped nanotip arrays for field emission with ultralow turn-on field
(2003-08-18)
Lo, HC
;
Das, D
;
Hwang, JS
;
Chen, KH
;
Hsu, CH
Silicon nanotips with tip diameter and height measuring 1 nm and 1 mum, respectively, and density in the range of 10(9)-3x10(11) cm(-2), were fabricated monolithically from silicon wafers by electron cyclotron resonance plasma etching technique at a temperature of 200 degreesC. Field emission current densities of 3.0 mA/cm(2) at an applied field of similar to1.0 V/mum was obtained from these silicon nanotips. High-resolution transmission electron microscope and Auger electron spectroscopy analyses concluded that the nanotips are composed of monolithic silicon and nanometer-size SiC cap at the top. A 0.35 V/mum turn-on field to draw a 10 muA/cm(2) current density was demonstrated, which is much lower than other reported materials. The excellent field emission property demonstrated by these nanotips, which were fabricated by a process integrable to the existing silicon device technology at low temperatures, is a step forward in achieving low-power field emission displays and vacuum electronic devices. (C) 2003 American Institute of Physics.