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本文介绍了随机共振现象,阐述了随机共振中添加噪声如何使信号增强。然后介绍了产生随机共振的经典实验和结果,并介绍了随机共振在阈下图像信号的检测、神经系统和脑电信号中的应用。最后,提出了随机共振研究中存在的一些问题和展望了随机共振的发展。 相似文献
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<正>直升机地面共振是一种涉及桨叶摆振运动和旋翼桨毂在旋转平面内运动耦合的动力不稳定现象,是直升机研制中必须加以克服和解决的问题。在进行其他飞行试验前,首先得通过专门的试验和分析计算,切实排除直升机发生地面共振的可能性。直升机地面共振试验一般包括地面共振计算分析所需的部件特性试验和地面共振外场开车试验。地面共振外场开车试验,应在地面共振分析之后,并表明直升机在旋翼全部工作转速范围内,不存在地面工作问题, 相似文献
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分析目前TV共振的主要原因和目前使用的一些对策,采用发明问题解决理论(TRIZ)手法,寻找解决共振问题的一些新方法,从而帮助我们减少共振发生的可能性,提高客户的满意度和降低市场的抱怨。同时,设计人员能够在设计初期就设计出理想的无共振的TV,提高产品的品质和降低成本。 相似文献
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介绍分布式共振模式扬声器的原理及特性,基于弯曲波原理进行声波辐射的换能器技术,不同于传统的活塞式换能器设计,利用平板材料的共振获得了扩散的、非相关的辐射特性,带来宽覆盖角和较少的声干涉,使分布式共振模式扬声器成为解决公共扩声环境下语言清晰度问题的新方案;并与传统扬声器进行对比。 相似文献
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利用数值模拟的方法研究了循环噪声对钙离子体系的积极影响。结果表明：在循环噪声的作用下,再注入噪声分数为ε=1时,随着噪声延迟时间的增加,钙离子体系表现出多重相干共振现象（Coherent Multiresonance,CMR）,且再注入噪声分数ε的正负不能改变相干共振的强度,只能改变相干共振极值的位置,但ε取值的大小对相干共振振幅有重要影响。若加入外信号,相干共振的峰值随着振幅的增大而增大,但不改变共振峰的个数;若振幅一定时,随着频率的变化相干共振的变化比较复杂。振幅和频率的改变,均使第一个相干共振的极值较大,说明在形成第一个相干共振峰时更容易使噪声能量集中在信号低频区域。 相似文献
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为了量化分析不同初始平衡磁剪切对共振磁扰动诱发的双撕裂模的影响,提出基于非线性多参数约束的不同初始平衡磁剪切对共振磁扰动诱发的双撕裂模控制模型。构建磁剪切对共振磁扰动诱发的控制约束参量模型,采用极低频外电场持续扰动方法进行不同初始平衡磁剪切对共振磁扰动建模,结合容积卡尔曼滤波方法进行共振磁扰动诱发的抑制处理,提取不同初始平衡磁剪切对共振磁扰动诱发的量化特征量。采用随机量化博弈和定量递归分析方法进行共振磁扰动诱发的双撕裂模自适应控制,分析共振磁扰动诱发对双撕裂模的稳定性控制因素,结合不同的刺激参数进行自适应参数估计和寻优,实现不同初始平衡磁剪切对共振磁扰动诱发的双撕裂模的定量递归分析。仿真结果表明,采用该方法进行共振磁扰动诱发双撕裂模的稳定性控制能力较好,收敛性较强,提高了双撕裂模的磁鲁棒性。 相似文献
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H.V. Putman 《Journal of The Franklin Institute》1924,197(5):603-621
The problem of calculating the resonance frequency and power pulsation of a synchronous motor direct connected to reciprocating apparatus is comparatively easy, provided the machine is operated from an infinite system, i.e., a system having constant voltage and frequency.In this paper a method is developed for calculating the resonance frequency of two synchronous machines electrically in parallel. It is also shown that in a system of n machines in parallel, there are (n - I) resonance frequencies. A general method of calculating these is given. Systems of three and four machines are treated as special examples of the general case. The theory is also given for calculating the actual power pulsations which occur in systems of two and three synchronous machines connected to reciprocating apparatus. With some approximation the theory is extended to four machines and a general method for n machines is suggested.Simple methods of calculating the correct sizes of flywheels necessary for the successful parallel operation of engine-driven generators are given. These are calculated directly from a knowledge of the resonance frequencies involved.In general the thesis is a mathematical treatment of the phenomena which occur in connection with hunting of synchronous machines, electrically in parallel and direct connected to reciprocating apparatus. Specific problems have been treated and illustrative examples presented which make quite clear not only the nature and causes of hunting, but also the methods of overcoming it. 相似文献
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The problem of reduced-order modelling is considered in connection with the design of restricted complexity controllers. The suggested reduction method develops in two phases: (i) a simple frequency response of the overall feedback control system is determined according to the design specifications; (ii) a reduced-order transference of the controlled plant is obtained by solving a linear set of equations in such a way that its behaviour approximates that of the original plant at frequencies which are meaningful for the overall transfer function derived in the first step (e.g. resonance and cutoff frequencies). An example shows how the procedure yields a reduced-order model suitable for designing robust controllers whereas other standard methods, based on properties of the plant only, fail. 相似文献
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《Information processing & management》2004,40(1):1-19
This paper presents a new adaptive filtering system called RELIEFS. This system is based on neural mechanisms underlying an information selection process. It is inspired from the cognitive model adaptive resonance theory [Biol. Cybernet. 23 (1976) 121] that proposes a neural explanation of how our brain selects information from its environment. In our approach, resonance, the key idea of this model is used to model the notion of relevance in information retrieval and information filtering (IF). The comparison of resonance with the previous models of relevance shows that resonance captures the very core of most existing models. Moreover, the notion of resonance provides a new angle to look at relevance and opens new theoretical perspectives. The proposed mechanism based on resonance has been directly implemented and tested on the TREC-9 and TREC-11 IF data. The experimental results show that this approach can result in a high effectiveness in practice. 相似文献
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《Research Policy》2019,48(9):103830
This paper depicts how cultural resonance for novel technologies is constructed as a gradual, interactive process. We adopt a cultural framing perspective and strive to understand how actors assign meaning to the novel technology and determine its appropriateness for the local context. Existing research has largely focused on the strategic and political aspects of field framing processes through depicting conscious framing struggles between protagonist and antagonist actors. In addition to such strategic framing activities, we examine how other socio-cultural factors, such as changes in actor positions, interaction between framing activities, and the cultural “repertoire” of frames interact in producing cultural resonance. For our empirical case study, we followed the emerging technological field of solar energy during an intensive period of change. Our study contributes to the growing number of studies that draw attention to the creation of cultural resonance as an interactive multi-actor process by offering in-depth understanding of the multifaceted interactions that constitute the meaning-making process for an emerging field. 相似文献
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传统的基于最小方差原理的反演结果依赖于初始模型选择,易陷入局部极小,针对以上问题,文章利用完全非线性反演方法-粒子群反演算法,对核磁共振探测地下水的数据资料进行反演解释,该算法具有操作简单,并行处理,不要求被优化的目标函数具有可微、可导、连续等性质的优点。将基本粒子群算法与模拟退火算法结合,加入非线性约束优化条件,使其适用于核磁共振探测地下水数据资料的反演解释。试验结果表明,混合粒子群反演算法反演结果精度较高,收敛速度较快,验证了粒子群优化算法在核磁共振反演应用中的可行性。 相似文献
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本文介绍了高频小信号LC谐振放大器的设计思路与具体电路实现,主要由衰减网络、LC谐振放大、电压跟随和电源四大模块组成。衰减器采用电阻式π型网络实现;LC谐振放大中选用功耗小的2N2222型三极管进行两级放大,LC谐振部分为放大器的负载;电压跟随采用集成运放OPA355,以实现电路阻抗的良好匹配;为了给放大器工作提供稳压电源,采用LM317稳压芯片设计了一个电源。经测试,放大器低功耗、高增益,具有良好的选择性。 相似文献
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Zois Boukouvalas Yuri Levin-Schwartz Vince D. Calhoun Tülay Adalı 《Journal of The Franklin Institute》2018,355(4):1873-1887
Because of its wide applicability in various disciplines, blind source separation (BSS), has been an active area of research. For a given dataset, BSS provides useful decompositions under minimum assumptions typically by making use of statistical properties—types of diversity—of the data. Two popular types of diversity that have proven useful for many applications are statistical independence and sparsity. Although many methods have been proposed for the solution of the BSS problem that take either the statistical independence or the sparsity of the data into account, there is no unified method that can take into account both types of diversity simultaneously. In this work, we provide a mathematical framework that enables direct control over the influence of these two types of diversity and apply the proposed framework to the development of an effective ICA algorithm that can jointly exploit independence and sparsity. In addition, due to its importance in biomedical applications, we propose a new model reproducibility framework for the evaluation of the proposed algorithm. Using simulated functional magnetic resonance imaging (fMRI) data, we study the trade-offs between the use of sparsity versus independence in terms of the separation accuracy and reproducibility of the algorithm and provide guidance on how to balance these two objectives in real world applications where the ground truth is not available. 相似文献
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《Research Policy》2022,51(3):104469
Strategic framing of a technology refers to activities that firms undertake to create favorable meaning for their technologies and foster their adoption. The success of such framing depends on the extent to which these technologies resonate with audiences within local settings. This paper examines how firms approach strategic framing activities to establish resonance in multiple local contexts when producing enabling technologies, i.e., novel technologies that address multiple and heterogeneous markets. Through a longitudinal case study of three companies that produce technologies to digitize smell and taste, this study offers a dynamic understanding of strategic framing by companies as they switch between different frames to establish resonance with audiences within and across markets. 相似文献
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采用数值模拟方法 ,研究了外部色噪音对蓝细菌生物钟体系的影响。结果表明,外噪音可以在体系的确定性稳态区诱导产生振荡和相干共振;在确定性振荡区,外噪音对振荡起到了破坏性作用,但是振荡的周期并没有随着外噪音的增加而明显变化,说明体系对外噪音具有鲁棒性;而在右侧分叉点附近的确定性振荡区,也发现了外噪音诱导相干共振现象。另外,研究了噪音相关时间的影响,发现其与噪音强度起相反的作用。 相似文献