共查询到20条相似文献，搜索用时 578 毫秒
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赵凡 《科技成果管理与研究》2013,(7):80-81
2013年1月18日,2012年度国家科学技术奖励大会在人民大会堂隆重举行,中科院生物物理研究所沈钧贤研究员主持的“凹耳蛙声通讯行为与听觉基础研究”项目荣获2012年度国家自然科学奖二等奖。该项研究证实了中国凹耳蛙是首个被发现独立进化、具有超声通讯能力的非哺乳脊椎动物,这是蛙声通讯研究领域的重大发现,同时,将启发探索许多物种未知的通讯方式,丰富动物通讯知识。Nature对此成果进行了评论,指出该项成果对研究动物声通讯具有重要意义。 相似文献
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人们将低等动物称无脊椎动物，高等动物则称脊椎动物。脊椎骨是生物在漫长进化过程中由脊索演化而来的。脊索动物中的典型代表是头索动物文昌鱼。头索动物主要特点是：脊索向前延伸至脑前部：没有特殊的发达感觉器官：循环系统闭锁式，没有心脏：分统器官分节明显；有中胚层发展而成的一些骨骼系统， 相似文献
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据对脊椎动物化石的研究,最早的脊椎动物可能出现于晚寒武世的海洋中,但可肯定的脊椎动物出现时期是奥陶纪。 脊椎动物进化过程中最大的进化事件之一是从水生到陆生。探讨这一问题是脊椎动物学中最重要,也最吸引人的课题之一。最原始的陆生脊椎动物是两栖动物,因 相似文献
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从高空俯瞰大地，森林似乎是这个嘈杂星球的最僻静之处。然而，这只是一种假象，实际上，森林并不安静，如果你仔细观察，你就会发现，密林深处到处弥漫着动物的各种通讯信号，尤其是一种由昆虫发射的，通过枝干和树叶传播的振动信号显得尤其怪异。事实上，有很多动物能发送通过植物传播的通讯信号，其数量之多可能超过了所有其他动物发送的信息信号。如果你能偷听它们之间的这些悄悄语，你一定会大吃一惊，这些看似简单的小虫子原来竞有如此丰富的信息词汇。 相似文献
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《Journal of The Franklin Institute》2021,358(15):7761-7785
This paper is dedicated to the stochastic bipartite consensus issue of discrete-time multi-agent systems subject to additive/multiplicative noise over antagonistic network, where a stochastic approximation time-varying gain is utilized for noise attenuation. The antagonistic information is characterized by a signed graph. We first show that the semi-decomposition approach, combining with Martingale convergence theorem, suffices to assure the bipartite consensus of the agents that are disturbed by additive noise. For multiplicative noise, we turn to the tool from Lyapunov-based technique to guarantee the boundedness of agents’ states. Based on it, the bipartite consensus with multiplicative noise can be achieved. It is found that the constant stochastic approximation control gain is inapplicable for the bipartite consensus with multiplicative noise. Moreover, the convergence rate of stochastic MASs with communication noise and antagonistic exchange is explicitly characterized, which has a close relationship with the stochastic approximation gain. Finally, we verify the obtained theoretical results via a numerical example. 相似文献
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The coordinated tracking problem where a group of followers intercepts a dynamic leader is studied. It is shown in this paper that reduction of inter-agent communication is obtained and improved performance is achieved when each follower implements dynamical models of neighbors and by using an event-triggered control strategy that requires each agent to send measurement updates only when necessary. The results in this paper consider directed graphs and the possible existence of cycles. Performance bounds on the tracking error have been obtained, which are functions of the communication topology and the event thresholds. This approach is extended to consider measurement noise and similar bounds are presented for this case. 相似文献
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体外循环心内直视手术时，工作人员和使用的仪器比其它手术时更多，手术室内的噪声比较大．通过五次心内直视手术时手术室内噪声的现场监测，最大噪声达１０５ｄＢ（Ａ），最小为４４．２ｄＢ（Ａ），平均为６３．８３±１０．２ｄＢ（Ａ）．手术室内的人声、人为噪声、医疗器械声（如吸引器、电锯、报警器声等）是噪声的主要来源．为减少开心手术室内的噪声污染，建议改进医疗仪器设备，提高手术人员的技术水平，并对用于大型手术的建筑设计应考虑到吸声措施． 相似文献
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Y.C. Jenq 《Journal of The Franklin Institute》1979,307(5):291-303
Data transmission via optical fiber is a new discipline of communication theory. The principal difference from conventional baseband data transmission, which is characterized by a signal independent additive Gaussian noise, is the existence of a signal dependent shot noise.This paper presents a technique for estimating the error probability performance of digital systems with inter-symbol interference and signal dependent additive noise. For binary antipodal (±1) systems, the approximate upper bound to the error probability is twice the lower bound. Hence either can be taken as a good approximation to the actual error probability. The technique is then applied to a model of some promising optical data communication systems and a good approximation to the error probability is obtained. Some observations about the effect of various system parameters on the error probability and some numerical examples are presented. 相似文献
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危机信息的传播模式与影响因素研究 总被引：14，自引：0，他引：14
本文利用Shannon和Weaver的信息传播模式建立了危机事件的信息模式，这种模式易于解释危机信息传播过程中所受到的影响因素。并从危机事件的属性、危机编码、通道、危机解码、噪声、危机反馈环节分析了影响危机信息传播效果的因素。 相似文献
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Xi-Sheng Zhan Ling-Li Cheng Jie Wu Huai-Cheng Yan 《Journal of The Franklin Institute》2019,356(12):6401-6418
This paper investigates the modified tracking performance limitation of the networked time-delay systems with two-channel constraints. We consider both the white Gaussian noise and packet dropout constraints in the communication channels. In the plant, the non-minimum phase, unstable poles and time-delay are considered. The modified tracking performance limitation expressions will be achieved using the co-prime factorization and the spectral decomposition technique, and the two-parameter controller is adopted. The results show that the modified tracking performance limitation is related to the intrinsic properties of the given plant, including the non-minimum phase zeroes, the unstable poles and the time-delay. Furthermore, the network communication parameters, e.g. the white Gaussian noise, the packet-dropouts probability and the modified factor affect the modified tracking performance limitation of the networked time-delay systems. Finally, some particular examples are provided to illustrate the efficiency of the proposed method. 相似文献
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Chaotic waveforms are natural information carriers since a correspondence can be established between the symbolic dynamics of a chaotic oscillator and the symbols of a message. Message symbols can be efficiently encoded in a chaotic waveform by applying vanishingly small perturbations to an oscillator to guide its symbolic dynamics to follow a desired course. Recently, two chaotic hybrid dynamical systems were shown to have matched filters enabling robust reception of chaotic communication waveforms in the presence of noise. The first of these, the exact shift oscillator, produces waveforms with desirable properties similar to antipodal signaling, but a physical implementation may be difficult to control using small perturbations. The second oscillator, the exact folded-band oscillator, produces less optimal waveforms but is more easily controlled. Here we introduce a method for generating waveforms of the exact shift oscillator by summing waveforms from a bank of easily controlled exact folded-band oscillators. We show that any solution of the exact shift oscillator can be so constructed using only three folded-band oscillators. Thus, this scheme allows us to realize the advantages of both chaotic systems while overcoming their individual disadvantages, thereby enabling practical chaos communications. 相似文献
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We propose a coding scheme for the stabilization of continuous linear scalar systems under a communication channel with finite data rate, lossy observations and network-induced delay. Owing to the network-induced delay, uncertain control input is introduced to the corresponding discrete time systems. Furthermore, since the system state is quantized to finite-bit signals and may be randomly lost in the communication, under the proposed coding scheme, the considered scalar system is described by a switched system of more than one dimension with arbitrary switchings. We derive the conditions for first moment stability of the systems, characterizing the relations on quantization cell boundaries, packet loss probabilities, and the network-induced delay. Further, we derive the condition for almost sure stability of the systems. A numerical method is proposed to search the infimum of the data rate for first moment stability under the given condition. It is shown that for the quantizer with the infimum of the data rate for first moment stability, although the quantization cells have different lengths, the matrices corresponding to these quantization cells have the same maximum eigenvalue. 相似文献
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MPEG-2是目前在视频通信中广泛应用的视频标准,由于其使用了VLC编码,增加了每个码流比特的重要性,而在某些复杂的传输环境中会引入很多噪声,这对视频解码的质量和完成都是有很大影响的。所以错误检测与掩盖技术在MPEG-2视频解码中非常重要。文章主要讨论MPEG-2解码器的噪声检测与错误掩盖的方法及其实现。 相似文献