Use of Non-Commercial Software for UNIX in Undergraduate Engineering Education
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Use of Non-Commercial Software for UNIX in Undergraduate Engineering Education James S. McDonald Department of Engineering Science Trinity University, San Antonio, TX 78212 Abstract Engineering Software The Department of Engineering Science curriculum This paper discusses the use of non-commercial spans a broad range of engineering areas, and this software for UNIX in the undergraduate engineering section surveys packages from several: electrical laboratory and classroom. Two main categories of engineering, mechanical engineering, systems and software are addressed: engineering applications across control, and general-purpose engineering tools a variety of disciplines, and graphical user interface The main advantages that have been observed in using components. Engineering applications are surveyed, non-commercial packages such as those surveyed are: and it is argued the best of these have several important · They are often intended for solution of textbook-like advantages over similar commercial packages in the problems, even if they are not expressly designed for context of engineering education. Graphical user tutorial purposes. This is very appropriate for interface components which allow the presentation of undergraduate students and reinforces theory learned these applications to students in a “user-friendly’’ way in the classroom. are surveyed, and several example GUIs are described. · “Bells and whistles” which are often found in Introduction commercial packages and which allow novice users to “get results” with little knowledge are generally The UNIX operating system remains important in the absent. It is usually necessary to understand the engineering industry and in engineering education at fundamentals of the problem at hand to get anywhere. both the graduate and undergraduate levels. The · Students are not “trained” on a particular vendor’s Department of Engineering Science at Trinity University currently-hot software package. has operated a network of UNIX workstations, currently · Documentation is generally excellent, and apt to be a mix of HP 9000/700 series and SunSparc systems, for written more like a textbook than a user’s guide. the last five years. During that time, almost all · Packages are generally developed at universities or engineering and other software on these systems has been non-profit research laboratories, many international. non-commercial in origin. This paper surveys some of This gives students an invaluable glimpse into the the most useful such software in two main categories: world-wide research community in engineering and engineering applications suitable for undergraduate some of its contributions. education and graphical user interface components. · Package developers are often graduate or even Some of the advantages of using non-commercial undergraduate students. This provides very positive software in each category are discussed. The software “peer pressure” on student users of the software. surveys are by no means exhaustive, but focus mainly on packages which have been used extensively in our Electrical Engineering department. SPICE [1] is the direct ancestor of almost all available Engineering software is the topic of Section 2, and circuit simulators. It contains all functionality necessary graphical user interface (GUI) software, including several for introductory circuits and electronics courses, and complete GUI examples, are discussed in Section 3. familiarity with it gives students a strongbackground for Additional materials are included on the CD-ROM learning more sophisticated commercial simulation edition of these Proceedings: packages. Although its graphics capabilities are · screen captures of many surveyed applications and all becoming antiquated, raw SPICE files are supported by example GUIs and the excellent xmgr plotting program, described below. · a compendium of relevantURLs phasor , circuit , and periodic , all products of the INTERACT project [2] at Cambridge, Heriot-Watt, and Strathclyde Universities, are excellent tutorial programs computed and vortices shed from the trailing edge can be for circuits and systems courses.phasor allows animated. visualization of multiple rotatingphasors and their sums Systems and Control in the complex plane. Amplitude, phase, and frequency Scilab, developed at INRIA, is a MATLAB-like package. of each phasor is adjustable and the summation feature In addition to all MATLAB functionality likely to be can be used to visualizeFourier series decompositions. needed in undergraduate systems and control courses, it is similar, allowing visualization of input and circuit has data types such as lists, symbolic polynomials, and output phasors (or sums ofphasors) of simple RLC transfer matrices, and advanced computational tools such circuits. periodic is aimed specifically at as linear matrix inequality solution and nonlinear visualization of Fourier series representations of periodic optimization. Two- and three-dimensional color signals. graphics and animation are built in. Many demos are pcb, developed by ThomasNau at the University ofUlm, included, as is an excellent manual set. is a printed circuit board design tool supporting up to octave [5] is a more modest MATLAB-like package eight-layer boards. Placement and routing are strictly which nonetheless contains all functionality likely to be manual (probably an advantage for educational use), but needed at the undergraduate level. It is also largely it is otherwise quite sophisticated. A rich, easily- MATLAB-compatible, allowing m-files to be ported extensible parts library, an excellent user guide, and a painlessly back and forth. Graphics support is provided sophisticated example layout are included. through gnuplot (see below), and an excellent manual Mechanical Engineering and other documentation are included. FElt [3] is a suite of easy-to-use finite-element codes sysresp, rlocus , and lgraph [6] are companion intended for introductory courses in the finite-element programs which provide sophisticated GUIs for the method. It supports basic elements including three- investigation of linear systems and classical control dimensional truss elements, two- and three-dimensional methods. sysresp allows entry of plant and Euler beams, two-dimensionalTimoshenko beams, and compensator transfer functions and display of various an eight-node brick element. It can perform linear static properties of the open- and/or closed-loop system, and dynamic analyses and has limited support for three- including Bode plots, step and impulse responses, root dimensional problems. The mainFElt application, locus, and state-space realizations.rlocus focuses on velvet , is a GUI-based problem definition, solution, the root locus computation and includes a tutorial mode and post-processing environment. Ancillary applications illustrating the basic rules for graphical construction of include felt (a batch mode solver) andcorduroy (a loci. Both programs support continuous real-time mesh generation tool). Documentation is excellent and visualization of system properties as poles and zeros are many examples are provided. added, deleted, or dragged using the mouse.lgraph AERO [4] is a three-dimensional rigid-body simulator. allows system entry using linear graphs. All three Basic objects such as spheres,cuboids, and planes, can be programs are excellent tools for learning basic linear graphically interconnected via link elements such as systems and classical control concepts. rods, springs, dampers, and joints. Objects have General-Purpose Engineering Tools adjustable parameters including density, damping factor, xmgr, developed by Paul Turner at the Oregon Graduate and coefficients of static and dynamic friction, while Institute, is a powerful two-dimensional data-plotting links have adjustable lengths and/or spring and/or package. It supports user-defined scaling, tick marks, damping coefficients. The overall system can be labels, symbols, line styles, and colors; reading and simulated, wire-frame-animated, and finally ray-traced to writing of setup parameters; linear regression,splines, produce realistic MPEG animations. running averages, DFT/FFT, and cross/auto-correlation; promech and airfoil are INTERACT tutorial input and output in many formats (including raw SPICE programs useful in mechanical engineering courses. input); and a batch mode. Up to ten graphs with up to promech supports the study of two-dimensional thirty data sets each can be produced on a single page. mechanisms; most can be graphically constructed from gnuplot , developed by ThomasWilliams and Colin standard elements, then animated and variables of Kelley at Dartmouth University, is a command-line interest plotted. airfoil allows the user to graphically driven function- and data-plotting package. It supports define an airfoil geometry and solves for both theinviscid two- and three-dimensional plots including surface and flow field and velocity potential. The boundary layer contour plots. Many output formats are supported, momentum integral equation is solved along the airfoil including LaTeX macros. gnuplot is also used as the and separations are calculated. Lift and drag are plotting engine for various packages, notablyoctave. xopps , developed by the MCA team in the Operations GUI Components Engineering Laboratory at NASA, is a full-featured Commercial UNIX GUIs and those which can be built Gantt chart creation tool which supports activities and from non-commercial components offer the user a wide events, current status display,