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一、概述 开关电源是一种新兴电源技术。开关电源不同于传统线性调整电源,它采用高频脉冲调制技术,可以使电源体积成倍下降,效率显著提高,重量明显减轻。 开关电源控制器是开关电源的关键部件之一,控制器集成化是提高电源电性能、可靠性及降低成本的重要措施。 相似文献
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无人机航空电子系统余度技术的利用大大提高了无人机系统的可靠性和安全性;通过分析多余度航空电子系统的可靠度方案,选取了合适的航空电子系统余度构型,并提出了适合三余度航空电子系统的余度架构和余度管理策略;另外对采用了基于余度策略的航空电子系统的关键技术——余度管理技术进行了研究,分析了航空电子系统余度管理的任务,在此基础上提出了管理算法方案;最后,建立了系统的可靠性模型,采用数值计算的方法,得到了系统可靠性的变化结果,为无人机航空电子系统余度设计提供了可供参考的依据。 相似文献
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崔何亮 《电子制作.电脑维护与应用》2018,(16)
凭借高可靠性和稳定输出而在电力电子系统中得到广泛应用的开关电源,亦有其自带电磁干扰,对整体系统的干扰必须得到人们的重视。为了应对电磁干扰所带来的影响,EMI滤波级联技术应运而生,同时仿真功率变换器的输出波形。 相似文献
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按照传统的观念,低功耗系统设计只是便携式电子系统中考虑的问题。而今已成为现代电子系统的普遍追求。这是因为低功耗是绿色电子的基本要求;高功耗是电子系统便携化趋势的主要障碍;低功耗系统具有可观的可靠性效益,而现代电子系统的普遍CMOS化又为低功耗设计提供了光明的前景。大规模集成电路的发展与应用,有赖于可靠性技术和低功耗技术的发展。CMOS超大规模集成电路的发展,促进了微电子器件中可靠性设计和低功耗设计技术的发展。如果说,早先的微电子thl设计工程师曾经求教过系统设计工程师的话,而今则是系统设计工程师要认真… 相似文献
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针对目前电声电子器件铜引线人工难以识别定位的问题,本文提出了基于机器视觉识别技术的微点焊机器人的系统,采用图像处理算法和机器视觉标定方法,解决电声电子器件铜引线的精确定位问题。实验结果证明,该系统能够有效提高微点焊的效率和质量。 相似文献
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针对目前网络流量不断增大、入侵特征规则数量迅速增加的情况,提出了一种双数组散列空间的模式匹配算法,可以有效地提高网络入侵检测系统的工作效率,并降低误报率。 相似文献
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OBJECTIVE: To evaluate the consistency of diagnostic data extracted from narrative electronic patient record (EPR) notes compared with the data from a patient administrative system (PAS). To assess potential benefit of using EPR notes as source of diagnosis data and as basis for case identification. DESIGN: Construction of a computer algorithm to extract ICD-9 codes from narrative EPR notes. Assessment of consistency and reliability of the diagnostic codes retrieved from EPR notes and PAS. Estimation of efficiency of case identification based on data from PAS and EPR. RESULTS: Diagnosis codes were retrieved from PAS with sensitivity of 0.989 and the positive predictive value (PPV) was 0.993. Codes were retrieved from EPR with sensitivity of 0.908 and PPV of 0.990. Combining these two sources increased sensitivity to 0.999. CONCLUSION: Discharge diagnoses were easily extracted from narrative EPR notes by automatic methods. Information extracted from record notes was not significantly different from the corresponding data in PAS, but EPR was incomplete as compared with PAS. Utilizing data extracted from EPR improved case identification significantly. 相似文献
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针对提供网上VOD服务中面临的恶意下载问题,本文给出了基于Windows Media Server认证插件的解决方案,详细设计了防恶意下载的算法,并给出了系统的具体实现.实验证明,本系统能有效防止恶意下载浪费流媒体服务资源的问题,大大提高VOD服务的质量和效率. 相似文献
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In this paper, we proposed a two-stage hybrid reliability analysis framework based on the surrogate model, which combines the first-order reliability method and Monte Carlo simulation with a doubly-weighted moving least squares (DWMLS) method. The first stage consists of constructing a surrogate model based on DWMLS. The weight system of DWMLS considers not only the normal weight factor of moving least squares, but also the distance from the most probable failure point (MPFP), which accounts for reliability problems. An adaptive experimental design scheme is proposed, during which the MPFP is progressively updated. The approximate values and sensitivity information of DWMLS are chosen to determine the number and location of the experimental design points in the next iteration, until a convergence criterion is satisfied. In the second stage, MCS on the surrogate model is then used to calculate the probability of failure. The proposed method is applied to five benchmark examples to validate its accuracy and efficiency. Results show that the proposed surrogate model with DWMLS can estimate the failure probability accurately, while requiring fewer original model simulations. 相似文献
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In this paper, we consider a single batch machine scheduling problem with incompatible job families and dynamic job arrivals. The objective is to minimize the total completion time. This problem is known to be strongly NP-hard. We present several dominance properties and two types of lower bounds, which are incorporated to construct a basic branch and bound algorithm. Furthermore, according to the characteristics of dynamic job arrivals, a decomposed branch and bound algorithm is proposed to improve the efficiency. The proposed algorithms are tested on a large set of randomly generated problem instances. 相似文献