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Object-Oriented Programming in LabVIEW
Published in Rick Bitter, Taqi Mohiuddin, Matt Nawrocki, LabVIEW™ Advanced Programming Techniques, 2017
Rick Bitter, Taqi Mohiuddin, Matt Nawrocki
An abstract class available to the LabVIEW programmer is the Instrument abstract class we designed in Section 10.3. This class requires several methods be supported. Methods to read and write should be required of all instrument derivatives, but serial instruments have different write implementations than GPIB instruments. Therefore, the Write method should be specified as a pure virtual function in the instrument base class. A pure virtual function is defined, but not implemented. This means that we have said this class has a function, but we will not tell you how it works. When a pure virtual function is defined in a class, the class cannot be instantiated into an object. A subclass may be instantiated, but the subclass must also provide implementation for the method.
C++ and Objective C
Published in Paul W. Ross, The Handbook of Software for Engineers and Scientists, 2018
Virtual functions are made so by prefacing their declaration within a base class by the keyword virtual. These functions are designed to be implemented by a derived class in a way meaningful to the derived class (i.e., a specialization over the general base class). A virtual function may optionally have an implementation in the base class. If so, and if the derived class does not implement this function, then the implementation in the base class serves as a default implementation for the derived class.
P
Published in Phillip A. Laplante, Dictionary of Computer Science, Engineering, and Technology, 2017
pure virtual function in C++ language, abstract classes (for which an implementation cannot exist) define some functions as virtual, but when no implementation can be provided, they became pure virtual by the means of “=0” initialization.
An energy-efficient and reliable data gathering infrastructure using the internet of things and smart grids
Published in Automatika, 2023
T. Vinothkumar, S.S. Sivaraju, Anuradha Thangavelu, S. Srithar
Price is another crucial aspect of cloud and fog. The two price-determining factors are the cost of information transport and the cost of virtual machines. U is a common factor and β is the transmission price per gigabyte. The cost factor with the given time is denoted in Equation (7). The cost function of distribution transmission, microgrid and the virtual machine are expressed . The cost function of the virtual function is denoted in Equation (8). The finish time of the virtual machine and the initial time of the virtual machine are denoted as . The constant factor is denoted .The cost function of the delay time is expressed in Equation (9). The total time is denoted , the user data is denoted , and the transfer cost is denoted .
Rapid transition of traditionally hands-on labs to online instruction in engineering courses
Published in European Journal of Engineering Education, 2022
Dominik May, Beshoy Morkos, Andrew Jackson, Nathaniel J. Hunsu, Amy Ingalls, Fred Beyette
The VISIR virtual workbench was designed to emulate the tactile learning experience that students receive when they build, power, and test a circuit in reality. The VISIR platform replicates the appearance and operational functionality of physical electronics lab bench equipment (i.e. moving components and rotating instrument knobs as you would on at physical lab bench). However, each students’ virtual lab bench can be accessed from any internet connection. Student users access the VISIR workbench (see Figure 1) remote lab environment through a web interface that enables them to use virtual versions of familiar benchtop instruments. In the VISIR workbench, students can access a virtual breadboard for building circuits with virtual wires and a set of basic discrete electronic components (e.g. resistors, capacitors, wires) to move onto their breadboard. A virtual power supply or a virtual function generator is used to power the circuits. Once properly wired, students can use additional instruments like a virtual multimetre or a virtual oscilloscope to take measurements and test the performance circuit. The developed virtual circuits are replicated using the VISIR technical back-end, which responds with real measurement data based on physically existing experimentation equipment.
Finite-time dynamic surface control using a novel nonlinear filter for nonlinear systems with input saturation and output constraint
Published in International Journal of Control, 2022
Yang Guo, Shaobo Wang, Shicheng Wang, Lixin Wang, Yanhua Tao
Step 1: Let and , where is a the stabilising virtual function. The Lyapunov function is chosen as where is the constraint on , that is, we require . It can be shown that is positive definite and continuous in the set , and thus a valid Lyapunov function candidate. It can be seen from Equation (30) that is the disturbance estimation error. The constructed stabilising virtual function as input passes through the novel nonlinear filter and obtains the virtual function . where , are the time constants of the filter. And the filter error of the nonlinear filter can be obtained which is , and the following equations can also be obtained as The time derivative of is given by