An experimental model of Chinese textual database

Abstract

A textual database deals with retrieval and manipulation of documents. It allows a user to search on‐line complete documents or parts of documents rather than attributes of documents. Resembling a formatted database which uses a data model as its underlying structure, a textual database has to base its development upon a document model. In this paper, a document model, called the ECHO model, is proposed. The ECHO model provides a document representation, called the ECHO structure, for expressing documents and operations on the representation that serve to express queries and manipulations on documents. It has the ability to provide multiple document structures for a document, a flexible search unit for retrieving textual information, and a subrange search on a textual database. In addition, the ECHO structure is relatively easy to maintain. An architecture of a textual database based on the ECHO model is also proposed. In order to improve the query performance, a refined character inversion method, called ARCIM, is proposed as the text‐access method of the Chinese textual database. The ARCIM can retrieve texts faster than a simple inversion method and requires less space overhead.     

Nanostructured alignment layer for liquid crystals

A new type of nanostructured alignment surface is proposed and demonstrated. As in previous nanostructured alignment surfaces, a large pretilt angle of near 45° can be produced reliably. Moreover, this new structure is fabricated with a mask, and there is no randomness involved. The uniformity and anchoring properties of this new surface have been measured to be of excellent quality.     

Transesterification of canola oil as biodiesel over Na/Zr-SBA-15 catalysts: Effect of zirconium content

A series of mesoporous Zr-SBA-15-supported Na catalysts was prepared and applied to the heterogeneous catalysis of canola oil transesterification. The effects of Si/Zr ratio, reaction time, and percentage of Na loading on the conversion to fatty acid methyl esters (FAME) were studied. The dependence of the textural structure and chemical properties of Zr-SBA-15 supports on Zr content was investigated using small-angle X-ray diffraction, Brunauer–Emmett–Teller analysis, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The results obtained from FTIR and TEM indicate that the incorporation of Zr atoms into the SBA-15 structure facilitated the formation of Brönsted acid sites and decreased the particle size of Na species. Catalysts with a higher Zr content enhanced the FAME yield. The optimum conditions determined were as follows: reaction temperature of 70 °C, 15 wt.% Na, reaction time of 6 h, and 12% catalyst content (wt.% oil) with a methanol/oil molar ratio of 6:1. The optimum conditions resulted in a FAME yield of up to 99%.     

Cluster-Based Saliency-Guided Content-Aware Image Retargeting

Straightforward image resizing operators without considering image contents (e.g., uniform scaling) cannot usually produce satisfactory results, while content-aware image retargeting aims to arbitrarily change image size while preserving visually prominent features. In this paper, a cluster-based saliency-guided seam carving algorithm for content-aware image retargeting is proposed. To cope with the main drawback of the original seam carving algorithm relying on only gradient-based image importance map, we integrate a gradient-based map and a cluster-based saliency map to generate a more reliable importance map, resulting in better single image retargeting results. Experimental results have demonstrated the efficacy of the proposed algorithm.     

Chemical stability and electrical and mechanical properties of BaZrxCe0.8-xY0.2O3 with CeO2 protection method

This study investigated the decline in the conductivity and mechanical strength after CO₂ poisoning and found a new protective method for BaZr_xCe_0.8-xY_0.2O₃ proton-conducting electrolyte. The high temperature solid state reaction (SSR) was used in synthesizing electrolyte to naturally generate CeO₂ on the surface. A comparison of the oxides in the conductivity decline test revealed that the sample with CeO₂ on the surface substantially improved the stability of conductivity, reducing the decline ratio from 56% to 7% for BCY electrolyte and 50% to 7% for BCZY sample. Raman mapping results indicate the naturally generated CeO₂ on electrolyte surface can considerably reduce impurity formation and maintain the microstructure of electrolyte. This work demonstrates that samples with CeO₂ on the surface effectively protect the BaCeO₃-based proton-conducting electrolyte from CO₂ poisoning. This method may be applied to similar BaCeO₃-based perovskite materials as a new protective method.     

Group-Based Authentication and Key Agreement

This paper presents an authentication and key agreement protocol to streamline communication activities for a group of mobile stations (MSs) roaming from the same home network (HN) to a serving network (SN). In such a roaming scenario, conventional schemes require the SN to interact with the HN for authenticating respective MSs, at the cost of repeated message exchanges and communication delay. Instead, in our design, when the first MS of a group visits, the SN performs full authentication with the concerned HN and thereby obtains authentication information for the MS and other members. Thus when any other MS of the same group visits, the SN can authenticate locally without subsequent involvement of the HN, so as to simplify protocol operations. We will show that our scheme does not trade performance for security and robustness to the extent that security requirements are unduly weakened. Both qualitative and quantitative discussions indicate that our proposed scheme lends itself to pragmatic settings.     

Cathodoluminescence and Field-Emission Properties of β-Ga2O3 Nanobelts

β-Ga₂O₃ nanobelts were synthesized using a vapor transport process in a controlled ambient. Structural characterization revealed that the as-synthesized samples consisted of monoclinic β-Ga₂O₃ nanobelts, and the presence of gallium-associated defects was verified using cathodoluminescence (CL). The formation of gallium-associated defects was explained by the insufficiency of the supply of cations, generating gallium vacancies on the (010) facet during growth. Furthermore, field-emission measurements indicated that β-Ga₂O₃ nanobelts exhibited defect-related electron emission. The turn-on fields of β-Ga₂O₃ nanobelts increased significantly with the degree of structural defects. For a sample prepared under 15% ambient oxygen, Fowler–Nordheim (F–N) analysis revealed two distinct field-enhancement factors of 1194 and 276, respectively. A correlation between field emission and structural defects was proposed. The experimental results demonstrate the presence of gallium-associated defects, which behave as electron traps, degrading the electron field-emission properties of β-Ga₂O₃ nanobelts.     

Managing Clouds, Smart Networks and Services: A Report on APNOMS 2011

This article presents a report on APNOMS 2011, which was held September 21–23, 2011 in Taipei, Taiwan. The theme of APNOMS 2011 was “Managing Clouds, Smart Networks and Services.”