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991.
基于光电传感器电路的迷宫机器人设计 总被引:1,自引:0,他引:1
采用Freescale公司的MC9SDG128单片机进行控制,使用ROHM公司生产的发送接收一体化反射型光电传感器RPR220,设计了一种新型迷宫机器人.该迷宫机器人能够在程序中严格控制光电传感器的开关,同时用软件消除外界干扰,取得了很好的探测效果. 相似文献
992.
在开发VxWorks嵌入式平台时,开发厂商会推出一整套交叉编译工具链来配合自身的嵌入式产品,但是这些由商业公司提供的工具链,都不会附有工具链相关的源代码和制作方法,灵活性不足,并且它们一般都与整套开发系统捆绑销售使用,成本较高.为了更好地理解这种技术和降低成本,使用了国际开源组织GNU开发的工具链作为产品开发的工具,提... 相似文献
993.
Ming Hua Jian Pei Xuemin Lin 《The VLDB Journal The International Journal on Very Large Data Bases》2011,20(1):129-153
Uncertain data is inherent in a few important applications. It is far from trivial to extend ranking queries (also known as top-k queries), a popular type of queries on certain data, to uncertain data. In this paper, we cast ranking queries on uncertain data using three parameters: rank threshold k, probability threshold p, and answer set size threshold l. Systematically, we identify four types of ranking queries on uncertain data. First, a probability threshold top-k query computes the uncertain records taking a probability of at least p to be in the top-k list. Second, a top-(k, l) query returns the top-l uncertain records whose probabilities of being ranked among top-k are the largest. Third, the p-rank of an uncertain record is the smallest number k such that the record takes a probability of at least p to be ranked in the top-k list. A rank threshold top-k query retrieves the records whose p-ranks are at most k. Last, a top-(p, l) query returns the top-l uncertain records with the smallest p-ranks. To answer such ranking queries, we present an efficient exact algorithm, a fast sampling algorithm, and a Poisson approximation-based algorithm. To answer top-(k, l) queries and top-(p, l) queries, we propose PRist+, a compact index. An efficient index construction algorithm and efficacious query answering methods are developed for PRist+. An empirical study using real and synthetic data sets verifies the effectiveness of the probabilistic ranking queries and the efficiency of our methods. 相似文献
994.
Szu‐Han Chen Ming‐Dou Ker Tzu‐Ming Wang 《Journal of the Society for Information Display》2011,19(8):539-546
Abstract— A digital time‐modulation pixel memory circuit on glass substrate has been designed and verified for a 3‐μm low‐temperature polysilicon (LTPS) technology. From the experimental results, the proposed circuit can generate 4‐bit digital codes and the corresponding inversion data with a time‐modulation technique. While the liquid‐crystal‐display (LCD) panel operates in the still mode, which means the same image is displayed on the panel, a data driver for an LCD panel is not required to provide the image data of the frame by the proposed pixel memory circuit. This pixel memory circuit can store the frame data and generate its corresponding inversion data to refresh a static image without activating the data driver circuit. Therefore, the power consumption of a data driver can be reduced in the LCD panel. 相似文献
995.
In this article, a novel single negative metamaterial (MTM) transmission line (TL) consisting of a Hilbert‐shaped complementary ring resonator (H‐CRR) on the ground plane is initially presented and studied in depth. Then based on the proposed MTM TL, a novel six‐section Hi‐Lo microstrip low‐pass filter (LPF) with a cut‐off frequency 2.5 GHz is developed, fabricated, and measured. Measurement results indicate that: by integrating H‐CRR, the selectivity has been significantly improved which is 77.3 dB/GHz due to the single negative permittivity; by etching a crown square on low‐impedance section, the bandwidth characterized by 20 dB return loss was obviously enhanced by 26.2% and the maximal sidelobe level of in‐band return loss was reduced from 22 to 24.6 dB. What' more, the developed LPF achieved a 36.3% size reduction with respect to its conventional counterpart. The design concept, which was confirmed by the measurement data, is of practical value and can be popularized in other microwave devices where high selectivity is requested. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. 相似文献
996.
Technological advancement has brought a whole new way of delivering financial services around the world. E-finance industry
in Malaysia has grown rapidly with the help of internet and conducting financial services are far easier now if compared to
last time. Internet provided a new medium or channel in delivering financial services. However, there are also risks and challenges
when using electronic finance. A total of 100 respondents had been targeted in completing this study. Survey method was utilized
in collecting respondent’s opinion and perception to test the variables. The target was companies which used electronic finance
in delivering their services. Interviews were also conducted and relevant tests conducted which provided evidence to support
the hypotheses for this study. It was found that e-finance was affected by security, revenue and cost dimensions, and technology
architecture with the adoption of global technology. 相似文献
997.
Wenbo Lu Jianhua Yang Ming Chen Chuangbing Zhou 《Simulation Modelling Practice and Theory》2011,19(9):2050-2062
Due to the complicated blasting load, the diversified medium models and various constitutive relations of the rock mass, and a huge job for simulating blasting of multiple holes, it is very difficult and costly to simulate the blasting vibration accurately in numerical computation. This paper presents an equivalent simulation method so as to transform this complex dynamic problem into an approximate initial-boundary problem. The equivalent elastic boundary applied by the blasting load was developed for multiple holes according to the spatial distribution of rock damage around each blasthole. The equivalent mechanics process of the complex blasting load was performed through analysis of the expansion of the borehole volume, the growth of cracks, the movement of stemming and the outburst of detonation gases. In combination with the blasting excavation of the tailrace tunnel in the Pubugou Hydropower Station, particle vibration velocities in the surrounding rock at different distances from the explosion source were simulated by applying this equivalent method based on the dynamic finite element method. The comparison with field monitoring data indicates that this equivalent simulation method is applicable to predicting the far-field dynamic response of the ground subjected to blasting load, and the selection of rock mass properties near the equivalent elastic boundary has a significant impact on simulation results. 相似文献
998.
针对线性阀体的内孔筒设计问题,建立了一个以过流面积和其逼近直线之间的平方误差最小为目标的泛函优化模型. 相似文献
999.
1000.