共查询到20条相似文献，搜索用时 234 毫秒
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对平衡的m阶相关免疫函数进行了研究，得到了两个重要结果：一个是平衡函数满足m相关免疫的充要条件，另一个是当m≥2/3n时，f（x）都是平衡的布尔函数。 相似文献
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本文研究了一类范数有界不确定离散状态时滞系统的鲁棒控制问题.通过采用新的方法,得到了使得系统鲁棒渐近稳定的改进的时滞相关准则,设计了使得系统鲁棒镇定的线性无记忆状态反馈控制器.所得时滞相关准则以严格线性矩阵不等式形式表示,且包含了更少的变量. 相似文献
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神经网络具有良好的非线性品质,能够实现非线性映射,并且具有在任意精度内逼近非线性映射的能力,直接表示出输入与输出间的复杂关系。为此,本文拟应用人工神经网络技术对沥青混合料的马歇尔试验性能进行预测。 1、BP神经网络及其算法人工神经元网络(简称神经网络),是对人类大脑系统的一阶特性的一种描述,是由大量的处理单元(神经元)通过适当的方式互连构成的高度复杂的大规模非线性自适应系统,可以用计算机程序来模拟。神经网络具有内部自组织、自学习的能力,能够不断适应外界环境的变化,通过对样本的学习,将未知对象判决为其最接近的记忆。人工神经网络还具有很强的容错性,善于联想、综合和推广。可以被用来完成数学上的映射逼近,数据压缩,模式匹配,系统建模,模糊控制,组合优化问题求解的任务。 相似文献
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给出了Galois环上弹性函数的一种构造方法:通过拟仿射函数组合若干弹性函数得到更高弹性阶的弹性函数。讨论了拟仿射函数的构造,结果显示存在丰富的拟仿射函数 相似文献
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对非线性分数阶导数的带有积分边界条件的微分方程存在性的研究,首先通过确界定理和单调有界定理,结合构造方法对连续函数性质进行证明,并对连续函数进行构造,在给定分数阶导数存在的条件下,引入扰动方法,利用Green函数定义非线性分数阶导数的微分方程积分算子。最后引入Banach压缩映像理论,证明了非线性分数阶导数的带有积分边界条件的微分方程的存在性。 相似文献
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在数字电路中,触发器是一种基本的逻辑记忆单元,具有的两种逻辑状态分别为0和1,即通常所说的没电或有电。电路中的触发器所具备的功能主要有三种,包括恢复功能、屏蔽功能、记忆功能,其中最为重要的是记忆信号功能,这也是构成时序电路最为基本的逻辑单元。为了进一步对数字电路触发器的应用进行分析,文章以智力竞赛抢答器设计为例,对抢答器电路中的触发器功能及运用进行了认识和探究。 相似文献
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科技项目的评选越来越多采用专家评价的方式，评审专家的打分质量直接影响科技项目的立项结果。为了提升科技项目的评价效果，管理部门通常建立评审专家库，并动态调整。本研究从第三方的角度，借鉴元评价的概念，基于评审专家的匿名打分结果对评审专家进行评价以支持专家库的动态调整。专家评审质量从三个方面进行定义，包括单项得分，最终得分，排序得分等角度；具体选取偏差系数、秩相关系数和二值法系数等评价指标。基于某政府科技部门2015年的1634个项目，分析了99位评审专家的实际评价数据。基于实证分析结果引入变异系数、参与度和立项率等调整系数建立了元评价综合模型。由管理部门结合评价过程和专家的实际身份特征等信息对综合评价模型的得分进行了验证分析，结果表明本研究提出的综合模型的可靠性和实践性满足项目管理部门的需求。最后，基于该模型，对科技项目管理部门如何提升专家评审质量给出了具体建议。 相似文献
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传统的多模干涉结构已经被应用在模式分裂器或合成器应用方面上。在这里,多模干涉结构被最优化设计为一种边缘滤波器,应用在了一种集成比率式波长检测仪方面上。一种整体最优化的模拟退火设计法在这篇文章里面得到了介绍和应用,设计方法包括：多模光波导的长度和宽度,输入和输出光波导的位置等等。最优化设计后的器件的光谱响应非常适于波长测量。 相似文献
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Tao Qin Xu-Dong Zhang Ming-Feng Tsai De-Sheng Wang Tie-Yan Liu Hang Li 《Information processing & management》2008
Many machine learning technologies such as support vector machines, boosting, and neural networks have been applied to the ranking problem in information retrieval. However, since originally the methods were not developed for this task, their loss functions do not directly link to the criteria used in the evaluation of ranking. Specifically, the loss functions are defined on the level of documents or document pairs, in contrast to the fact that the evaluation criteria are defined on the level of queries. Therefore, minimizing the loss functions does not necessarily imply enhancing ranking performances. To solve this problem, we propose using query-level loss functions in learning of ranking functions. We discuss the basic properties that a query-level loss function should have and propose a query-level loss function based on the cosine similarity between a ranking list and the corresponding ground truth. We further design a coordinate descent algorithm, referred to as RankCosine, which utilizes the proposed loss function to create a generalized additive ranking model. We also discuss whether the loss functions of existing ranking algorithms can be extended to query-level. Experimental results on the datasets of TREC web track, OHSUMED, and a commercial web search engine show that with the use of the proposed query-level loss function we can significantly improve ranking accuracies. Furthermore, we found that it is difficult to extend the document-level loss functions to query-level loss functions. 相似文献
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Xinli Yin Bailong Yang Jianxiang Xi Xiaojun Yang 《Journal of The Franklin Institute》2019,356(7):4061-4075
The current paper addresses leader-following guaranteed cost synchronization with the cost budget given previously for the second-order wireless sensor networks. The published researches on guaranteed cost synchronization design criteria usually are based on the linear matrix inequality (LMI) techniques and cannot take the cost budget given previously into consideration. Firstly, the current paper proposes a guaranteed cost synchronization protocol, which can realize the tradeoff design between the battery power consumption and the synchronization regulation performance. Secondly, for the case without the given cost budget, sufficient conditions for leader-following guaranteed cost synchronization are presented and an upper bound of the cost function is shown. Thirdly, for the case that the cost budget is given previously, the criterion for leader-following guaranteed cost synchronization is proposed. Especially, the value ranges of control gains in these criteria are determined, which means that the existence of control gains in synchronization criteria can be guaranteed, but the LMI techniques can only determine the gain matrix and cannot give the value ranges of control gains. Moreover, these criteria are only associated with the minimum nonzero eigenvalue and the maximum eigenvalue, which can ensure the scalability of the wireless sensor networks. Finally, numerical simulations are given to illustrate theoretical results. 相似文献
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This paper presents a new transformation by which the stability-equation method can be applied for analysis and design of sampled-data systems. New stability criteria applicable to systems with transfer function having both real and complex coefficients are presented. Several kinds of examples are considered with computer results given. 相似文献
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Novel closed-form expressions for the probability density function and the average output signal-to-noise ratio at the output of a selection combiner in Weibull fading are derived. Using these expressions, the spectral efficiency of a direct sequence code division multiple access system is analytically obtained and performance evaluation results are presented. 相似文献
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Search engines and other text retrieval systems use high-performance inverted indexes to provide efficient text query evaluation. Algorithms for fast query evaluation and index construction are well-known, but relatively little has been published concerning update. In this paper, we experimentally evaluate the two main alternative strategies for index maintenance in the presence of insertions, with the constraint that inverted lists remain contiguous on disk for fast query evaluation. The in-place and re-merge strategies are benchmarked against the baseline of a complete re-build. Our experiments with large volumes of web data show that re-merge is the fastest approach if large buffers are available, but that even a simple implementation of in-place update is suitable when the rate of insertion is low or memory buffer size is limited. We also show that with careful design of aspects of implementation such as free-space management, in-place update can be improved by around an order of magnitude over a naïve implementation. 相似文献
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基于传输函数的信号流图模拟,一种新的具有最少元件 Ｏ Ｔ Ａ电容滤波器结构被提出⒚任何种类任何阶电压传输函数均可由该结构实现,设计公式简单⒚文中设计了各种二阶滤波器,分析了这种实现的电压传输函数的灵敏度,给出了三阶椭圆低通滤波器设计实例及计算机仿真结果⒚ 相似文献