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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. 相似文献
83.
In semiconductor manufacturing, hot lots are to provide marketing and engineering with extra flexibility regarding delivery lead times, and in turn enhance its competitive advantages against other companies. On the other hand, hot lots are among major sources of disruption of the smoothness of the manufacturing flow. They can lead to a significant increase of cycle time of normal lots, and in turn result in delayed delivery times and serious service deteriorations. Due to the complex nature of semiconductor manufacturing, evaluating the impact of hot lots on the cycle time of normal lots presents major challenges. In this paper, we propose a methodology, called progressive simulation metamodelling (PSM), that allows for an efficient development of the response surface between the cycle time of normal lots and the percentage of hot lots in semiconductor manufacturing. The response surface generated by the proposed PSM is like an easy-to-use analytical model, but with the fidelity of simulation that takes into account all important manufacturing details. The specially-designed mechanisms, including identifying the critical region and sequentially adding design points in the critical region, further grants PSM computational advantages compared to the traditional response surface method. An empirical study conducted in collaboration with a semiconductor company validates the viability of PSM in real settings. 相似文献
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85.
A study on the formation of a measurement scale for the environmental quality of Taiwan’s long-term care institutions by the Delphi method 总被引:1,自引:0,他引:1
Yen Ping Hsieh Yen Wen Hsieh Chia Ching Lin Chien Wen Yeh Sing Chiao Chang 《Journal of Housing and the Built Environment》2012,27(2):169-186
This study used a two-round modified Delphi technique with a questionnaire survey in order to reach a consensus for the questionnaire; the survey was conducted from September to December 2009. The six indicators for the environmental quality of long-term care institutions in Taiwan are (1) indoor environmental quality, (2) safety equipment for the prevention and management of disasters occurring in residents?? daily lives, (3) provision for assistive devices for residents?? daily use, (4) provision for privacy and individualized space, (5) provision for comfortable and decorated indoor environments, and (6) provision for social interaction space. The scale included 34 items with an acceptable number of panel members and acceptable construct validity. Panel members all highly approved of Indicators 1, 2, and 6. Although they approved of Indicator 3, they suggested that caregivers at institutions should replace the functions of living assistive devices. They approved of Indicator 5; however, they questioned the method for providing comfortable and decorated environments. They approved of Indicator 4; however, they suggested that private space need not be provided in the living room of the institution. In terms of long-term care institution environments in Taiwan, Indicators 1, 2, and 6 were important for protecting residents?? physical and psychological well-being and improving their social interactions. Indicator 3, although important, could be directly replaced by caregivers. Indicator 5 required more implementation methods, while Indicator 4, the living room of the institution, was considered unnecessary. 相似文献
86.
Hsuan-Han Lai Chih-Chun Hsieh Chi-Ming Lin Weite Wu 《Metals and Materials International》2017,23(3):499-503
The eutectic (Cr,Fe)-(Cr,Fe)23C6 showed a triaxial fishbone structure and could be categorized as a “complex regular structure”. In this study, the lattice relations of the fishbone (Cr,Fe)23C6 were examined and the solidification process was observed using a transmission electron microscope and a confocal laser scanning microscope. For one of the three fish bones in a eutectic cell, parallel (Cr,Fe)23C6 lamellas at one side of the spine had the same lattice direction, as did those in the (Cr,Fe) phase. The lattices of neighboring (Cr,Fe)23C6 and (Cr,Fe) phases were not coherent. Lamellar (Cr,Fe)23C6 on opposite sides of a spine had different lattice directions, and their lattice boundary was in the spine. By using the confocal laser scanning microscope, the solidification of lamellar eutectic structure could be observed. At the low cooling rate of 5 o C·min-1, parallel lamellas would grow thick blocks instead of thin plates. To obtain a thin lamellar eutectic structure, the cooling rate should be higher, like the rate in welding. 相似文献
87.
Tzong-Liu Wang Chien-Hsin YangYeong-Tarng Shieh An-Chi YehChin-Hsiang Chen Tsung-Han Ho 《Materials Chemistry and Physics》2012,132(1):131-137
CdSe-poly(N-vinylcarbazole) (CdSe-PVK) nanocomposite was synthesized and utilized as the electron acceptor in the active layer of polymer solar cells. The photovoltaic properties of the polymer solar cells based on poly(3-hexylthiophene) (P3HT):CdSe-PVK as the active layer were investigated in detail. The effects of annealing temperature (100-200 °C) and time (5-60 min) on the device performance were studied. At annealing temperature of 150 °C for 30 min, the device demonstrated an optimal efficiency of 0.235% under AM 1.5 (100 mW cm−2) solar simulated light irradiation. The improved efficiency under the optimal conditions was confirmed by the highest light harvest in UV-vis spectra due to the increased crystallinity of P3HT after thermal annealing. Photoluminescence of these devices also exhibited that the quench effect increases with the increasing of annealing temperature, indicating that the charge separation between electron-donating (P3HT) and electron-accepting (CdSe-PVK) molecules was increased after heat treatment. Atomic force microscopy (AFM) images showed that the phase segregation and 3D interpenetrating networks of P3HT:CdSe-PVK were responsible for the enhancement of the device efficiency. 相似文献
88.
Tanya L. Chantawansri Yelena R. Sliozberg Jan W. Andzelm Alex J. Hsieh 《Polymer》2012,53(20):4512-4524
Poly(urethane urea) elastomers are versatile and can be tailored to exhibit a broad range of mechanical response under high strain rate deformation. In this work, we utilize coarse-grained molecular dynamics simulations to elucidate the molecular mechanisms, particularly the effects of hard segment content, intermolecular interaction, and rigidity of the interface between the hard and soft segments on local morphology and rate-dependent stress-strain behavior in the ballistic regime. Simulation results qualitatively agree with available experimental data, where analysis of hard segment orientation during tensile and compression deformation and dynamic strain rate sensitivity was also performed. Further study of the intermolecular interaction on the stress-strain behavior reveals that it has a strong effect on strain hardening, particularly for a rigid interface, once the hard segment content reaches the percolation threshold. Simulation results also show that interface intermolecular interaction could become more dominant over interface rigidity in the initial stress-strain response, particularly below percolation. 相似文献
89.
Zhou Qingguo Feng Fang Shen Zebang Zhou Rui Hsieh Meng-Yen Li Kuan-Ching 《Multimedia Tools and Applications》2019,78(3):3529-3552
Multimedia Tools and Applications - With the increasing number of malicious attacks, the way how to detect malicious Apps has drawn attention in mobile technology market. In this paper, we proposed... 相似文献