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Chung Y.-F.,Tunghai University | Chen Y.-T.,National Chiao Tung University | Chen T.-L.,Taiwan University | Chen T.-S.,Tunghai University
Expert Systems with Applications | Year: 2011

Rapid development of the Internet and the extensive use of mobile phones have increased demand for mobile devices in Internet auctions. This trend is acting as an incentive to develop an auction model for mobile-based environment. Recently, Kuo-Hsuan Huang proposed a mobile auction agent model (MoAAM), which allows the bidders to participate in online auctions through a mobile agent. He used modular exponentiation operations in his method. As a result, the processing time for key generation, bidding, and verification were long. Thus, we propose to add the concept of Elliptic Curve Cryptosystem (ECC) onto MoAAM, because ECC has low computation amount and small key size, both of which will aid to increase the speed in generating keys, bidding, and verification. In terms of reduction of computation load on mobile devices and auction-manager server, the proposed method will make online auction system more efficient as well as more convenient to use. This paper mainly uses the English auction protocol as the key auction protocol. The protocol consists of four entities: Registration Manager (RM), Agent House (AH), Auction House (AUH), and Bidders (B). The Registration Manager registers and verifies Bidder identity. The Agent House manages the agents and assigns public transaction keys to Bidders. The Auction House provides a place for auction and maintains all necessary operations for a smooth online auction. Bidders are buyers who are interested in purchasing items at the auction. Our proposed method conforms to the requirements of an online auction protocol in terms of anonymity, traceability, no framing, unforgetability, non-repudiation, fairness, public verifiability, unlinkability among various auction rounds, linkability within a single auction round, efficiency of bidding, one-time registration, and easy revocation. © 2011 Published by Elsevier Ltd. Source

Huang N.,Lanzhou University | Zhang Y.,Lanzhou University | Zhang Q.,Taiwan University | Chen C.-K.,Continental Water Engineering Corporation | Chang C.-T.,Ilan University
Journal of Nanoscience and Nanotechnology | Year: 2014

TiO2 nanotubes were prepared by hydrothermal process, then characterized using Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Visible spectroscopy measurements. The photodegradation performance assessment of Reactive Red 141 (RR141) with near visible light irradiation (λ = 380 nm) was carried out under different catalyst doses, dye concentrations, pH and initial Cr(VI) concentrations by TiO2 powder and nanotubes. The results showed that the specific surface area of TiO2 nanotubes were 152 m2 g-1, about three times larger than that of TiO2 powder which was roughly 51 m2 g-1. The TiO2 nanotubes did not affect the lattice structure of the TiO2. The adsorption amount increases as the dosage and RR141 concentration increases. However, the decolonization efficiency decreased with increasing initial RR141 concentration. Results also showed that an acidic solution is more favorable for photocatalytic degradation of RR141. On the other hand, Cr(VI) can be adsorbed on the surface of TiO2 nanotubes to affect the decolonization efficiency of RR141. Copyright © 2014 American Scientific Publishers. Source

Ma Y.,Xiamen University | Ouyang T.,Xiamen University | Chen O.-P.,Taiwan University | Chen C.-K.,Continental Water Engineering Corporation | Chang C.-T.,Ilan University
Journal of Nanoscience and Nanotechnology | Year: 2014

Polyaniline/titanium nanotube composite (PANI/TNT) photocatalysts were prepared by 'in situ' chemical oxidative polymerization of aniline. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR spectra (FTIR) and UV-Visible spectroscopy measurements were used to characterize the obtained photocatalysts, and their photocatalytic activities were investigated by degrading Reactive Green19 (RG19) under near visible light irradiation (λ = 365 nm). The content of PANI, pH, dosage, and concentration of RG19 were also investigated. The results showed that the inner diameter of the PANI/TNT was 6 nm and that the PANI did not change the structure of the TNT. The PANI was coated on the surface of the TNT. The light response of the PANI/TNT was extended to the visible-light regions. Among the six different kinds of photocatalysts, the 1.17 wt% PANI/TNT had the best performance in treating 10 ppm RG19. The best pH is 3 for the largely protonated surface of the composite at low pH. The adsorption amount was increased as the dosage increased. The decolonization efficiency decreased with increasing initial RG19 concentration. The performance of the photocatalyst in decomposing RG19 was stable after 5 time. Copyright © 2014 American Scientific Publishers. cycles. Copyright © 2014 American Scientific Publishers. Source

Song J.,Yantai University | Wang X.,Yantai University | Chen O.-P.,Taiwan University | Chen C.-K.,Continental Water Engineering Corporation | Chang C.-T.,Ilan University
Separation Science and Technology (Philadelphia) | Year: 2015

Graphene-titanium nanotube composites with different ratios of graphite oxide were prepared via the hydrothermal method using ascorbic acid as a reducing agent. Properties of materials were characterized by X-ray diffraction, Fourier Transform Infrared Spectroscopy, high resolution transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The average diameter of the titanium dioxide nanotubes was about 8 nm. The photoresponse of nanocomposites have been extended to visible-light regions. In addition, graphene-titanium nanotube composites showed higher photocatalytic degradation efficiency for reactive black 5 (RBK5) than pure titanium dioxide and the 15%graphene-titanium nanotube composites catalysts possessed the best photocatalytic activity. The degradation efficiency for RBK5 dyes increased with increased dosage of graphite oxide from 3%-15% and decreased with increasing initial RBK5 concentration. This paper not only reports the fabrication of highly active photocatalysts but also provides insight into the photocatalytic mechanism of graphene-titanium nanotube composites. Copyright © Taylor & Francis Group, LLC. Source

Lu R.,China University of Geosciences | He D.,China University of Geosciences | Suppe J.,Taiwan University | Meng Z.,China University of Geosciences | And 2 more authors.
Scientia Geologica Sinica | Year: 2011

The M s 8.0 Wenchuan, China, earthquake ruptured two large thrust faults along the Longmen Mountains thrust belt. Between them, the co-seismic fault in Pengguan thrust belt created the second longest surface ruptures. In this paper, in order to distinguish the co-seismic fault in Pengguan thrust belt, the fine interpretation of seismic profiles in the central Longmen Mountains have been accomplished by take advantage of geology map, drilling data and 2D/3D seismic reflection profiles, Our studies found that the Pengguan thrust belt have three main faults and another branch faults. The main faults are developing imbricated structure in the shallow strata and among them are developing the duplex. The co-seismic fault which made the surface ruptures in the Pengguan thrust belt is the (3) fault, that is also the largest fault in the front of central Longmen Mountains. These faults are formed with flat and ramp and they are steep at the surface but the angle dip decreased with the depth increasing. Our studies indicated that these fault were generating in the Late Triassic period, developing in the Late Jurassic period and keeping on activity in the Cenozoic period. According to characteristics of geology, the main fault and the co-seismic surface ruptures, the front of central Longmen Mountains can be divided into two sub-segments, one is the Bailu area and the other is Hanwang area. The characteristics of shallow structures in the Pengguan thrust belt could provide some details and restriction for the research of faults in the front central Longmen Mountains. Source

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