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951.
Active Directory是Windows2003 Server全新的目录管理方式,它是一种层次化、树状、可扩展、可伸缩的目录结构。文章通过介绍活动目录的相关知识和安装与配置,在计算机房的具体配置,应用于机房的管理中,提高管理效率。 相似文献
952.
高精度二相混合式步进电机控制系统研究 总被引:4,自引:2,他引:2
在二相混合式步进电机数学模型的基础上,针对电机低速运行时的振动和噪声过大的问题,研究了正弦脉宽调制细分驱动技术,开发出一种新型的基于单片机的多细分二相混合式步进电机驱动器。该系统主要分为数字控制部分、GAL片逻辑综合信号处理单元、SG3525恒流控制电路、驱动功放电路、过流保护及反馈电路和系统供电电源模块等。系统采用专用集成芯片和可编程逻辑器件,以8位单片机AT89C2051为控制核心,实现恒流控制、正/反转运行、过流保护和多档位细分等功能。实验结果表明,系统硬件和软件设计合理可行,各项技术指标均达到了设计要求。 相似文献
953.
Wei-Der Chang 《Digital Signal Processing》2009,19(4):693-699
This paper presents a novel secure communication system for digital signal transmissions. It contains four important parts: modulation, chaotic transmitter, chaotic receiver, and demodulation. The modulation mechanism is to modulate each of delivered bit information to be a carrier signal in the continuous form. Then this carrier signal is taken as a parameter of the chaotic system, called the unified chaotic system. Such a system possesses three different types of chaos characterizations depending on its system's parameter, and this guarantees the communication security more. In the public channel, only three chaotic state variables are delivered and this means that the important carrier information is efficiently screened. According to chaotic states received in the receiver terminal, the continuous carrier signal is decrypted using certain adaptation mechanisms. Finally, the proposed demodulation method can successfully recover the original bit information which is embedded in the communication systems. Some simulation results are provided to verify the efficiency of the proposed secure communication system. 相似文献
954.
Youn‐Gyoung Chang Seong‐Hee Nam Nam‐Kook Kim Yun‐Ho Kook Jinook Kim Soon‐Sung Yoo Chang‐Dong Kim In‐Byeong Kang In‐Jae Chung 《Journal of the Society for Information Display》2009,17(4):301-307
Abstract— Recently, potential breakthrough technologies for low‐cost processing of TFT‐LCDs and new process developments for flexible‐display fabrication have been widely studied. A roll‐printing process using etch‐resist material as a replacement for photolithographic patterning was investigated. The characterization of the properties of patterns formed in roll printing, a method to fabricate cliché plates for fine patterns, and the design of a new formulation for resist printing ink is reported. The pattern position accuracy, which is one of the most important issues for the successful application of printing processes in display manufacturing was studied and how it can be improved by optimizing the blanket roll structure is explained. New design rules for the layout of the thin‐film‐transistor array was derived to improve the compatibility of roll printing. As a result, a prototype 15‐in.‐XGA TFT‐LCD panel was fabricated by using printing processes to replace all the photolithographic patterning steps conventionally used. 相似文献
955.
Jyh‐Wen Shiu Kuo‐Chang Lee Chao‐Chiun Liang Yuan‐Chang Liao Chen‐Chu Tsai Janglin Chen 《Journal of the Society for Information Display》2009,17(10):811-820
Abstract— A 3‐m‐long rugged flexible display having a novel single‐plastic‐substrate structure has been demonstrated with a coated cholesteric liquid‐crystal mixture. The display is designed to be fabricated by a roll‐to‐roll process to increase productivity at a competitive cost. It has the advantage of having almost no limitation in display length. The high‐resolution (300‐dpi) monochrome cholesteric liquid‐crystal display (ChLCD) can be achieved by using a photo‐addressing method. A single‐layered 10.4‐in. color ChLCD also has been developed with good color and contrast. 相似文献
956.
Chang‐Wook Han Yoon‐Heung Tak In Byeong Kang Byung‐Chul Ahn In Jae Chung 《Journal of the Society for Information Display》2009,17(2):101-106
Abstract— An improved AMOLED with an a‐Si TFT backplane based on a unique structure is reported. The new structure is refered to as a dual‐plate OLED display (DOD). While a top‐emission OLED array is directly fabricated on a TFT backplane, the DOD consists of an upper OLED substrate and a lower TFT substrate, which are independently fabricated. Because the OLED substrate, which is fabricated through the process flow of bottom emission, is attached to the TFT substrate, the light is emitted in the opposite direction to the TFT backplane. The DOD enables the design of large‐sized TFTs and a complicated pixel circuit. It can also not only achieve higher uniformity in luminance in large‐sized displays due to the low electrical resistance of the common electrode, but also wider viewing angles. 相似文献
957.
User experimentation: an evaluation of velocity control techniques in immersive virtual environments
While many of the existing velocity control techniques are well designed, the techniques are often application-specific, making
it difficult to compare their effectiveness. In this paper, we evaluate five known velocity control techniques using the same
experimental settings. We compare the techniques based on the assumption that a good travel technique should be easy to learn
and easy to use, should cause the user to have few collisions with the VE, should allow the user to complete tasks faster,
and should promote better recollection of the environment afterwards. In our experiments, we ask twenty users to use each
velocity control technique to navigate through virtual corridors while performing information-gathering tasks. In all cases,
the users use pointing to indicate the direction of travel. We then measure the users’ ability to recollect the information they see in the VE,
as well as how much time they spend in the VE and how often they collide with the virtual walls. After each test, we use questionnaires
to evaluate the ease of learning and ease of use of the velocity control technique, and the users’ sense of presence in the
environment. Each of the travel techniques is then evaluated based on the users’ performances in the VE and the results of
their questionnaires. 相似文献
958.
In a highly competitive market, customers' product affection is a critical factor to product success. However, understanding customers' affective needs is difficult to grasp; product design practitioners often misunderstand what customers really want. In this study we report our experience in developing and using an affective design framework that identified critical affective features customers have on products and are systematically incorporated into product design attributes. To identify key affective features such as luxuriousness, we utilized the Kansei engineering methodology. This approach consists of three steps: (1) selecting related affective features and product design attributes through a comprehensive literature survey, expert panel opinion, and focus group interviews; (2) conducting evaluation experiments; and (3) developing Kansei models using multivariate statistical analysis and analyzing critical product design attributes. To demonstrate applicability of the proposed affective design framework, 30 customers and 30 product design practitioners participated in an evaluation experiment for car crash pads, and 44 customers and 20 designers participated in an evaluation experiment for two interior room products (wallpapers and flooring materials). The evaluation experiments were conducted via systematically developed questionnaires consisting of a 7‐point semantic differential scale and a 100‐point magnitude estimation scale. The results of the experiments were analyzed using principal component regression and quantification theory type I method. Using the analyzed survey data, the relationship between luxuriousness and related affective features and product design attributes were identified. This relationship indicated that there was a significant difference in the perception of luxuriousness between customers and designers. Consequently, it is expected that the results of this study could provide a foundation for developing affective products. © 2009 Wiley Periodicals, Inc. 相似文献
959.
Yau-Zen Chang Jung-Fu Hou Yung-Pyng Chang Shih-Tseng Lee 《Artificial Life and Robotics》2009,14(2):228-232
In this article, we investigate the problem of integrating a binocular stereo vision system and a laser range finder to construct
a 3-D map of the environment. The proposed scheme is realized by using the alignment parameters obtained in the 2-D map construction
of the laser range finder for the 3-D data generated by the stereo vision system. The 2-D map alignment task is formulated
as an optimization problem of minimizing the alignment errors between local maps and selected parts of the developing global
map. The problem is then solved using the Simplex method. To increase the robustness of the searching process, multiple initial
guesses are provided in the Simplex method. The performance of the proposed architecture is verified by experimental results
from a mobile vehicle for obstacle avoidance. 相似文献
960.
Knowledge, experiences and skills of corporate members promote new ideas into products, in the context of innovative design. This dynamism is especially important in the critical product conceptualization stage. In customer-oriented design paradigm, most methodologies focus on exploiting end-user requirements, instead of considering project stakeholder requirements in a holistic manner. Previous research in the area of innovative product conceptualization focused on such aspects as functional, cognitive, marketing and commercial perspectives. It involves the participations of customers, designers, engineers, marketers and business managers. Accordingly, a stakeholder-oriented innovative product concept development system (IPCDS) is established to integrate the bespoke four perspectives so as to evaluate product concept innovation comprehensively. To resolve the incomplete, ambiguous, uncertain and subjective nature of innovative design knowledge, the product platform represented in a design knowledge hierarchy (DKH) is generated using general sorting. Subsequently, an innovative design criteria matrix (DCM) constructed using repertory grids technique is rated with regard to specific design option. The ratings are then used as input features to the fuzzy integrals technique, for the purpose of innovative design. A case study on cellular phone design is used for system illustration and the results are discussed on the basis of product concept innovation. 相似文献