共查询到20条相似文献，搜索用时 15 毫秒
1.
电铃在实际生活中应用广泛,但是手动控制打铃可靠性差,噪声多,而且单独布线浪费工时和成本,为了解决可靠性差、减少不必要的噪声及布线问题,该设计主要介绍了一种以EasyARN11138单片机为核心,以七段数码管显示年、月、日、时、分和星期,时钟芯片DS12887计时并校时的无线电铃控制器。单片机根据时钟信号及事先编好的打铃... 相似文献
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文章从视频服务器系统,数据库服务器,播出控制系统,系统防病毒措施,时钟及同步系统和供电系统等方面充分阐述广西电视台在系统安全性的设计上的考虑。 相似文献
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本文对时钟芯片DS1302的读时序进行了详细分析,设计了基于DS1302的数字钟,包括硬件电路的设计和软件程序的设计,并在Proteus软件中进行了仿真实验。结果表明,该数字钟具有工作可靠、结构简单等优点。 相似文献
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针对传统多带宽合成孔径雷达系统需要多个滤波器和多种采样时钟等问题,提出一种新的数字处理方法,并详细介绍了算法方案、仿真结果和基于现场可编程门阵列(FPGA)的算法实现.该方法仅需一个最高频率的采样时钟获取离散化数据,通过对数据的插值得到其他较低时钟频率的数据,而对不同带宽信号的滤波由数字滤波器来实现.这种方法简化了系统设计,提高了系统可靠性. 相似文献
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TTP／C在汽车网络中应用的研究 总被引：1，自引：0，他引：1
近年来,伴随着汽车电子系统网络化进程的加快,CAN作为一种事件驱动型的网络,无法提供下一代线控系统应用所需的容错功能或带宽,因此又有许多新型网络被开发出来。如以TFP／C（Time Triggered Protocol,Class C）为代表的X-线控（X—by—wire）技术在车载网络中的应用日益成熟,汽车“线控”系统对控制动作的实时性和系统可靠性要求非常高,因此,使用时间触发的协议对安全性要求高的转向和制动等方面是有利的。 相似文献
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《Journal of The Franklin Institute》2022,359(9):4260-4287
In this paper, we formulate and study a reliability-performance balancing problem (RPBP) for long-term operational and unattended control systems with degrading actuators. It preliminarily explores a new type of autonomous maintenance method to extend the useful lifetime of the control system. The actuator, as the crucial component of a control system, executes calculated control actions and thereby is often exposed to the high-load working environment. As the actuator degrades, the control action will gradually alter with increasing magnitude to maintain the desired control performance, but this will accelerate the actuator degradation and thus reduce the useful lifetime (use reliability) of the control system. Therefore, conditionally balancing the control performance and use reliability is meaningful, for which a novel dynamic regulation strategy under the model predictive control (MPC) framework is proposed. Specifically, we model the actuator degradation using a diffusion Wiener process coupled with the control action or system state, and the corresponding actuator reliability is derived. By fusing the degradation model and system dynamics, a degradation-incorporated state space (DISS) model is formulated, in which the basic idea is to consider the actuator degradation as an extended state variable and to control it accordingly. Based on the DISS model, a mixed-index nonlinear MPC integrated with a weight tuning strategy is proposed to achieve a satisfactory balance between control performance and use reliability in the presence of actuator degradation. Further, the reference curve and the upper bound of actuator degradation are given for constructing the objective function and the constraint in the MPC optimization problem. An illustrative example is presented to demonstrate the availability of the proposed method. 相似文献
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文章介绍了一种基于CPLD的高频电路的多路不同频率同步时钟输出模块的设计方法,采用单一高频时钟作为时钟源输入,通过CPLD的分频电路设计实现输出多路不同频率同步时钟,利用有限状态基设计实现CPLD的外部控制接口,实现对CPLD输出时钟频率的任意调节。有效满足复杂的高频电路设计中需要提供多路不同频率同步时钟的要求。 相似文献
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《Journal of The Franklin Institute》2021,358(15):7447-7467
Protection and reliability enactment of electrical systems are important and emerging in power system research. Nowadays, it is very evident that the implementation of an intelligent algorithm is found in the field of substation equipment protection and relaying purposes. Majority of the researches are based on single load connected to a single feeder line and validated using simulation. A hardware based implementation and validation system will be an additional aspects. In this paper, we have discussed an expert system based intelligent relaying scheme by incorporating fuzzy algorithm in microcontroller. Purpose is to control the moving contacts of the breaker part for controlling multiple loads connected to a single feeder line. This paper reports the entire performance of intelligent relaying mechanism only considering stage - I with respect to non-fuzzy based relaying scheme and successfully achieved fastest coordination time after validating it under IEEE 13 Bus system. We have also validated the cascaded fuzzy based system and a non-fuzzy based system using ATMEL microcontroller. 相似文献
9.
Zhou Gu Tao Zhang Fan Yang Huan Zhao Mouquan Shen 《Journal of The Franklin Institute》2019,356(4):1955-1974
This paper deals with the event-triggered control for networked cascade control systems. Unlike conventional event-triggered schemes that predetermine a fixed threshold to reduce the data-releasing rate, this paper proposes a novel event-triggered mechanism (ETM) in an adaptive way. Under this ETM, it has the following merits: (1) the data-releasing rate remains at a lower level so as to save limited network bandwidth; (2) the reliability of control systems can be improved since the threshold of ETM is increased gradually with the elapse of time till the next event is generated. An integrated model of networked cascade control systems with consideration of stochastic nonlinearity, actuator failures and ETM is established. Sufficient conditions are obtained to ensure the mean-square stability and stabilization of networked cascade control systems. Finally, two examples are exploited to show the effectiveness of the proposed method. 相似文献
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提出了一个结构系统可靠性分析的载荷传递路线并联模型,讨论了结构系统可靠度的计算、载荷传递路线集的枚举主要载荷传递路线集的鉴别。所举的两个算例表明,结构系统可靠性分析的载荷传递路线模型是有效的。 相似文献
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十字路口的交通管理是日常生活中最常见的一种交通管理模式。通过编写十字路口直行交通演示程序,可以帮助C#的初学者较熟练地掌握时钟控件的使用方法。十字路口直行交通演示程序的基本设计思想是设置3个时钟控件,分别控制十字路口的绿灯持续时间、黄灯闪烁时间、车辆驶停状态,达到模拟十字路口的直行交通状况的目的。 相似文献
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R.T Balmer 《Endeavour》1979,3(3):118-122
The simple draining liquid clepsydra (water clock) was in use in Egypt by 1500 B.C. The replacement of the liquid with a fine granulated material, thus converting the clepsydra into a clepsammia (sand clock), appears not to have occurred before the mediaeval period. What human need was then met by the sand clock that could not be met by a water clock or early mechanical clock? 相似文献
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机械零部件的安全可靠是机械设计的主要目的之一，由于工程材料性的离散性以及制造、安装误差等因素的影响，使机械零部件的参数具有固有的随机性，因此研究这种机械系统的可靠性问题有十分重要的意义，这种研究可以帮助工程设计人员合理地建立机械系统的安全容限和控制随机参数对机械系统安全的影响．将可靠性设计理论与灵敏度分析方法相结合，讨论了螺旋管簧的可靠性的参数灵敏度分析问题，提出了可靠性灵敏度设计的计算方法，研究了正态分布设计参数的改变对螺旋管簧可靠性的影响，给出了可靠性灵敏度的变化规律，根据编制的相关的实用程序，可以迅速准确地得到螺旋管簧的可靠性灵敏度设计信息，为螺旋管簧的可靠性设计提供了理论依据。 相似文献
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Finite-time stability involves dynamical systems whose trajectories converge to an equilibrium state in finite time. In this paper, we consider a general class of fully actuated mechanical systems described by Euler–Lagrange dynamics and the class of underactuated systems represented by mobile robot dynamics that are required to reach and maintain the desired trajectory in finite time. An approach known as the terminal sliding mode control (TSMC) involves non-smooth sliding surfaces such that, while on the sliding surface, the error states converge to the origin in finite time thus ensuring finite-time tracking. The main advantage of this control scheme is in fast converging times without excessive control effort. Such controllers are known to have singularities in some parts of the state space and, in this paper, we propose a method of partitioning the state space into two regions where the TSMC is bounded and its complement. We show that the region of bounded TSMC is invariant and design an auxiliary sliding mode controller predicated on linear smooth sliding surface for the initial conditions outside this region. Furthermore, we extend these results to address TSMC for underactuated systems characterized by the mobile robot dynamics. We demonstrate the efficacy of our approach by implementing it for a scenario when multiple dynamic agents are required to move in a fixed formation with respect to the formation leader. Finally, we validate our results experimentally using a wheeled mobile robot platform. 相似文献
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《Journal of The Franklin Institute》2022,359(14):7438-7457
This article investigates the adaptive regulation problem of uncertain delayed nonlinear systems. Remarkably, the systems have multiple delays in systems’ states and the input, and the nonlinear terms as a whole can belong to one of four different growing conditions. By introducing the dynamic-gain-based transformations, we obtain the new dynamic systems. By using homogeneous domination method, adaptive regulation strategy and by flexibly selecting the dynamic gain, two unified adaptive control methods are presented such that the obtained systems are globally asymptotic stable. Simulation results verify the effectiveness of the methods of this paper. 相似文献
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介绍罗克韦自动化公司Pico控制器的功能和特点，及其在煤炭装卸线控制系统中的应用，讨论系统的结构、工作原理、硬件组成和软件设计。该系统结构简单，可靠性高，特别适用于恶劣的工作环境。 相似文献
19.
《Research Policy》2023,52(6):104762
The Entrepreneurial Ecosystems (EE) approach makes specific predictions regarding how EE inputs are converted into high-growth firms (HGFs) as an output. A simulation model draws out our hypothesis of regional persistence in HGF shares. Based on intuitions that EEs are persistent, we investigate whether regional HGF shares are persistent, using census data for 2 European countries taken separately (Croatia for 2004–2019, and Slovenia for 2007–2019). Overall, there is no clear persistence in regional HGF shares – regions with large HGF shares in one period are not necessarily likely to have large HGF shares in the following period. This is a puzzle for EE theory. In fact, there seems to be more persistence in industry-level HGF shares than for regional HGF shares. We formulate a ‘broken clock’ critique – just as a broken clock is correct twice a day, EE recommendations may sometimes be correct, but are fundamentally flawed as long as time-changing outputs (HGF shares) are predicted using time-invariant variables (such as local universities, institutions, investments in R&D and infrastructure). 相似文献
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In this article we highlight temporal effects in information and communication technology-enabled organizational change. Examples of temporal effects are explored in the context of one organization's efforts to implement an enterprise-wide information system. Temporality is presented as having two aspects, with the first being the well-recognized, linear and measured clock time. The second aspect of time is that which is perceived--often as nonlinear--and socially defined. We find that temporal effects arise both in changes to the structure of work and in differences among groups in how time is perceived. Evidence suggests that both specific characteristics of the implementation and of the enterprise systems' technologies further exacerbate these temporal effects. We conclude with suggestions for how to incorporate a temporally reflective perspective into analysis of technology-enabled organizational change and how a temporal perspective provides insight into both the social and technical aspects of the sociotechnical nature of enterprise systems. 相似文献