Teaching Spreadsheet-Based Numerical Analysis with Visual Basic for Applications and Virtual Instruments

LabVIEW, EXCEL and VBA are currently used in a number of engineering schools and industries for simulation and analysis. By introducing virtual instrumentation (LabVIEW) and EXCEL/VBA to the existing laboratory facilities and course(s) the students can be well trained with the latest design techniques and computer aided instrumentation, design and process control used throughout industry. This will also allow the students greater interaction with the subject matter and improve his/her skills in the use of number of applied engineering software packages. This paper will discuss design and development of interactive instructional modules for Numerical Analysis Course using LabVIEW, EXCEL and VBA. Introduction The students’ over reliance upon formulas and routine use of technique in problem solving too often lead to poor performance in advanced courses and a high attrition rate in the engineering, technology, and science programs. The students’ lack of comprehension of mathematical concepts results in time wastage during laboratory experiments, misinterpretations of lab data and underachievement in standardized science and engineering tests that stress the fundamentals 1, 2, 3, 4 . This problem can be effectively addressed by improving the student’s conceptual understanding and comprehension of the topics covered in introductory science and technology courses. One way to achieve this is through interactive learning and teaching and upgrading the existing laboratories with modern equipment. This will require increased funding and resources. But in recent years there is a decrease in resource allocation making it increasingly difficult to modernize the laboratories to provide adequate levels of laboratory and course work and universities are under pressure to look for alternative cost effective methods. One way to achieve this is through interactive learning and teaching through the use of software packages like LabVIEW (Virtual Instruments), Excel and Visual Basic for Applications (VBA). These programs along with MatLAB, Mathematica and Maple are used to teach courses such as Numerical Analysis and Engineering Problem Solving. This paper discusses some of the numerical analysis instructional modules using LabVIEW, EXCEL and VBA. Numerical Analysis Instructional Modules using LabVIEW Approximately 10 to 15 years ago, National Instruments Corporation introduced a new program called LabVIEW. The acronym stands for Laboratory Virtual Instrumentation Engineering Work Bench. Originally designed for test and measurement applications, the program has been modified over the years to design and analyze various complex systems. LabVIEW is a graphical programming environment and is based on the concept of data flow programming. The data flow programming concept is different from the sequential nature of traditional programming languages, and it cuts down on the design and development time of an application. It is widely accepted by industry, academia, and research laboratories around the world as a standard for data acquisition and instrument control software. Since LabVIEW is based on graphical programming, users can build instrumentation called virtual instruments (VIs) using software objects. With proper hardware, these VIs can be used for remote data acquisition, P ge 22402.2 analysis, design, and distributed control. The built-in library of LabVIEW has a number of VIs that can be used to design and develop any system. LabVIEW can be used to address the needs of various courses in a technology and science curriculum 6, 7, 8, 9 . LabVIEW Application Areas LabVIEW is extremely flexible and some of the application areas of LabVIEW are Simulation, Data Acquisition, and Data Processing. The Data Processing library includes signal generation, digital signal processing (DSP), measurement, filters, windows, curve fitting, probability and statistics, linear algebra, numerical methods, instrument control, program development, control systems, and fuzzy logic. These features of LabVIEW will help provide an interdisciplinary, integrated teaching and learning experience that integrates team-oriented, hands-on learning experiences throughout the engineering technology and sciences curriculum, engaging students in the design and analysis process beginning with their first year. The Mathematics VIs of LabVIEW are located on the Functions»Analyze»Mathematics palette. These VIs can be used to perform many different kinds of mathematical calculations. The following is a listing of VIs in LabVIEW: 1D and 2D Evaluation VIs, Linear Algebra VIs, Array Operations VIs, Numeric Functions VIs Calculus VIs, Optimization VIs, Curve Fitting VIs Probability and Statistics VIs Formula VIs, and Zeroes VIs. The user has to provide appropriate inputs and outputs in the LabVIEW Control Panel and make required connections in the LabVIEW diagram panel to simulate these VIs. Example VI to solve system of linear equations This VI solves the following linear equations: 5x1 + x2 + 3x3 = 5 2x1 + 7x2 + 9x3 = 4 8x1 + 6x2+ 4x3 = 9 The linear equations are written in Matrix Form (Ax = B) form and then A and B (known vector) are supplied as inputs to the VI. The VI solves for the roots and displays the results as shown in Figure 1. The VI is flexible and can be easily modified to accommodate more number of equations by simply changing the dimension of A, B, and solution vector.