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1.
This paper concentrates on computing the stabilizing region
of PDμ controller for fractional order system with general interval uncertainties and an interval delay. The stabilizing region means the complete/approximate set of PDμ controllers that stabilize the given closed-loop control system. General interval uncertainties refer to both coefficients and orders of the fractional system suffer from interval uncertainties. Interval delay indicates that the delay also vary in a specified interval.Firstly, a method is presented to calculate the stabilizing region for general interval fractional system with an interval
time-constant delay. Based on a novel mapping function and the concept of critical controller parameters, the stabilizing region can be determined numerically. Secondly, the stabilizing region computation problem for general interval fractional system with an interval time-varyingdelay is considered. By applying a revised small-gain theorem, the stabilizing region can be calculated like the time-constant delay case. Thirdly, two alternative methods are proposed to improve the computational efficiency of stabilizing region calculation. Both methods can reduce the number of polynomials which are used to determine the stabilizing region. Examples are followed to illustrate the proposed results. 相似文献
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《Journal of The Franklin Institute》2023,360(9):6566-6584
This work concentrates on the control design of interval type-2 (IT2) T–S fuzzy systems under probabilistic saturation constraints. The actual control signals are allowed to exceed some preset thresholds with a certain frequency. Meanwhile, the sensors are governed by the multi-node round-robin scheduling protocol, which permits more than one sensors to transmit their information at every moment. The main objective is to synthesize a fuzzy controller such that the closed-loop system is locally stochastically stable under probabilistic saturated constraints and the multi-node round-robin scheduling protocol. To this end, the probabilistic saturation constraints are characterized by a Bernoulli-distributed stochastic process, and the received state at the controller side is formulated based on an updating rule and a compensation strategy. By constructing new membership functions, a token-dependent control law is subsequently designed. The stability analysis is facilitated by a modified sector condition dealing with the saturation nonlinearities. With suitable selection of initial states, sufficient conditions are derived to achieve the local stochastic stability of the closed-loop IT2 T–S fuzzy system. A larger domain of stochastic stability can be obtained via a searching algorithm. Finally, the proposed method is illustrated via a simulation example. 相似文献
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The sampled-data H∞ filtering for a continuous-time Takagi–Sugeno fuzzy system with an interval time-varying state delay is investigated, where the measurement outputs from the plant to the filter are assumed to be sampled at discrete instants with a variable period. Firstly, by means of a newly proposed inequality bounding technique and a new Lyapunov–Krasovskii functional, the fuzzy sampled-data H∞ filtering performance analysis is carried out such that the resultant filter error system is asymptotically stable with a prescribed H∞ attenuation performance index. Secondly, sufficient conditions on the existence of fuzzy sampled-data H∞ filters are derived in the simultaneous presence of the time-varying state delay and the variable sampling period. The proposed bounding inequality lies in its more tightness and alleviates the enlargement of some inverse “coefficients” resulting from the utilization of the well-known Jensen integral inequality . Compared with some existing Lyapunov–Krasovskii functionals, more information about the relationship among the current state and its delayed state is considered. The upper bound of the derivative of the time-varying state delay is not required to be less than one. Different from some existing results in the literature, by applying the proposed results, each different value of such an upper bound (greater than one) leads to a different H∞ disturbance attenuation level. Finally, a numerical example and a modified continuous stirred tank reactor system are given to show the effectiveness of the proposed results. 相似文献
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《中国科学院院刊(英文版)》2006,20(2):116-119
The Academy of Opto-Electronics (AOE) is an institution under the direct jurisdiction of the CAS headquarters. Organizationally, it has six components: the head office, the Changchun Institute of Optics, Fine Mechanics & Physics (CIOMP), the Shanghai Institute of Technical Physics (SITP), the Xi’an Institute of Optics & Precision Mechanics (XIOM), the Shanghai Institute of Optics & Fine Me- chanics (SIOM) and the Institute of Optics & Electron- ics (IOE) in Chengdu. The p… 相似文献
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In this paper we consider a class of fractional order linear time invariant (FO-LTI) interval systems with linear coupling relationships among the fractional order, the system matrix and the input matrix. We present the sufficient conditions for the robust stability and stabilization of such coupling FO-LTI interval systems with the fractional order α satisfying 0<α<1. All the results are proposed in terms of linear matrix inequalities (LMI). Two numerical examples show that our results are effective for checking the robust asymptotical stability and designing the stabilizing controller for FO-LTI interval systems. 相似文献
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《Endeavour》2020,44(1-2):100717
Mario Bunge, the centenarian Argentine/Canadian physicist/philosopher passed away in the loving company of his wife Marta and children Eric and Silvia on February 24, 2020 in Montréal, Ontario. This memoriam reviews his life and work, particularly his contributions to physics and philosophy of science. 相似文献
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《科学学与科学技术管理》2012,33(2)
创业企业通过嵌入战略联盟获取竞争优势,但合作绩效往往低于预期水平。综合社会网络、行为科学和公平性等理论基本思想,探明合作绩效主要影响因子,并通过Pearson相关分析构建了影响＂科技企业孵化器—风险投资—在孵企业＂三方合作绩效的路径概念模型。实证分析结果为三方合作绩效与合作成功率提出了加强合作方的参与度、促进合作网络结构优化,并关注科技企业孵化器的＂桥梁＂作用与战略伙伴选择的无形资源拟合的对策。 相似文献
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Concept,Characteristics and Future of Cold-type Wheat 总被引：1，自引：0，他引：1
Zhang Songwu 《中国科学基金》2007,21(1):51-57
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Byungchae Jin 《Research Policy》2019,48(1):385-400
This study investigates whether country-level technological disparities influence individual scientists’ choice of research agenda and, if so, how the effect of country-level technological disparities on individuals’ research activities differs before and after technology commercialization. To address these research questions, we use research proceedings published from the International Electric Vehicle Symposium (EVS) from 1990 to 2009. We find that a country’s technological capabilities tend to prevent its scientists from studying electric vehicles (defined as a disruptive technology) but encourage them to study hybrid vehicles (defined as a sustaining technology) before electric and hybrid vehicles are launched in the automobile market. We also find that a country’s technological capabilities do not subsequently help its scientists shift their research activities to the technologies that have received positive initial feedback from automobile markets. 相似文献
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《中国专利与商标》2011,(2):98-101
To deal with the new situation and address the new issues encountered by the Public Security Authorities, the People＇s Procuratorates and the People＇s Courts in recent years in handling criminal cases arising from intellectual property infringement, punish criminal activities of intellectual property infringement under the laws, and safeguard the order of the socialist market economy, these Opinions have been formulated as follows under the Criminal Law, the Criminal Procedure Law, and the relevant judicial interpretation on the basis of the practice of investigation, prosecution and trial. 相似文献
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Lazear (2005) suggests that entrepreneurs should be generalists, while those who work for others should be specialists. Many prospective entrepreneurs will develop varied skills by engaging in a variety of employment activities prior to becoming an entrepreneur, and incomes are higher for those that do so. An alternative view predicts that those with greater taste for variety are more likely to become entrepreneurs. Varied employment prior to becoming an entrepreneur is simply an expression of this taste, and is associated with lower earnings. Data from a survey of 830 independent inventors and 300 individuals from the general population are used to discriminate between these two theories. The results show that inventor-entrepreneurs typically have a more varied labor market experience, and that varied work experience is associated with lower household income. 相似文献
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《中国科学院院刊(英文版)》2004,(3)
Arecent study conducted by researchers from Hong KongandCASscientists hasuncovered the secret of spermmaturation. As reported recently by NatureCell Biology, the study has revealedthat Bin1b, a β-defensin gene foundin the head regionof the epididymis,can bind to a sperm head and induceprogressivespermmotility inanorigi-nally immotileimmature sperm. The investigation of the role ofthe novel epididymis-specific gene,Bin1b, is a collaborative project ofthe Epithelial … 相似文献
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Ronald Pethig 《Biomicrofluidics》2010,4(2)
A review is presented of the present status of the theory, the developed technology and the current applications of dielectrophoresis (DEP). Over the past 10 years around 2000 publications have addressed these three aspects, and current trends suggest that the theory and technology have matured sufficiently for most effort to now be directed towards applying DEP to unmet needs in such areas as biosensors, cell therapeutics, drug discovery, medical diagnostics, microfluidics, nanoassembly, and particle filtration. The dipole approximation to describe the DEP force acting on a particle subjected to a nonuniform electric field has evolved to include multipole contributions, the perturbing effects arising from interactions with other cells and boundary surfaces, and the influence of electrical double-layer polarizations that must be considered for nanoparticles. Theoretical modelling of the electric field gradients generated by different electrode designs has also reached an advanced state. Advances in the technology include the development of sophisticated electrode designs, along with the introduction of new materials (e.g., silicone polymers, dry film resist) and methods for fabricating the electrodes and microfluidics of DEP devices (photo and electron beam lithography, laser ablation, thin film techniques, CMOS technology). Around three-quarters of the 300 or so scientific publications now being published each year on DEP are directed towards practical applications, and this is matched with an increasing number of patent applications. A summary of the US patents granted since January 2005 is given, along with an outline of the small number of perceived industrial applications (e.g., mineral separation, micropolishing, manipulation and dispensing of fluid droplets, manipulation and assembly of micro components). The technology has also advanced sufficiently for DEP to be used as a tool to manipulate nanoparticles (e.g., carbon nanotubes, nano wires, gold and metal oxide nanoparticles) for the fabrication of devices and sensors. Most efforts are now being directed towards biomedical applications, such as the spatial manipulation and selective separation∕enrichment of target cells or bacteria, high-throughput molecular screening, biosensors, immunoassays, and the artificial engineering of three-dimensional cell constructs. DEP is able to manipulate and sort cells without the need for biochemical labels or other bioengineered tags, and without contact to any surfaces. This opens up potentially important applications of DEP as a tool to address an unmet need in stem cell research and therapy. 相似文献
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《中国科学院院刊(英文版)》2005,(4)
SCIENCE WATCHAgricultureA New Strain of High-yield Wheat…………………………133ArcheologyChinese People Make Wine 9,000 Years Ago…………………9Evidence of the Earliest Salt Production Found in China…215Earliest Yet Noodles Made 4,000 Years ago in China………216AstronomyAstronomers Put Forward New Theory of Galaxy Formation……22A Circumstellar Disk Observed around a Massive Star……197Atmospheric ScienceProgress in Aridification Studies……………………………12Automation… 相似文献
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Maienschein J Smith G 《Isis; an international review devoted to the history of science and its cultural influences》2008,99(2):318-321
This essay opens up the question of what difference the history of science makes. What is the value of the history of science, beyond its role as an academic pursuit that we historians of science know and love? It introduces the set of essays that follow as explorations that grew out of a seminar on this topic and that arise from the authors' particular concerns both that historians of science do not work hard enough to make their work of value and that others do not know of the potential. That seminar, at the Marine Biological Laboratory, was funded for nineteen years by the Dibner Institute and last year by Brent Dibner. It will continue and carry such discussions forward in new ways as the Arizona State University-Marine Biological Laboratory History of Biology Seminar Series. This set of focused essays seeks to invite lively discussion and response. 相似文献