Interactive Graphical Tool Research Articles

The Role of Interactive Graphic Tools in Teaching Control Theory

The availability of commercial computer-aided design packages has had a substantial effect on teaching of control theory. Computer aids have become an essential part of modem control engineering curriculum. This paper discusses the role of recent interactive graphical tools in teaching control theory. These tools are normally used in conjunction with interactive computer-aided design packages. However, the use of interactive graphical tools is particularly significant because they provide practical insight into control system fundamentals. They make possible an early introduction of concepts such as linearization, effects of nonlinearities, integrator-windup, time delays etc. on the performance of a control system. At the same time, they allow for demonstration of design iterations interactively. Hence design iterations using classical methods (root locus, Bode) and modern methods (LQG, H ∞ ) may be carried out in a very instructive fashion. The use of interactive graphical oriented tools would reinforce active participation of students

Chaotic behavior of finite inertia particles in ABC flow

Lagrangian trajectories in ABC flow have been studied by Dombre et al.1 for the purpose of analyzing chaos in three-dimensional Hamiltonian systems. In this paper we report on the study of finite particles (i.e., particles with inertia and dissipation) embedded in an ABC flow. Both linear and nonlinear drag models were examined. Because the dynamics must be represented in a six-dimensional phase space (rather than three dimensions for the pure Lagrangian ABC flow), and such high dimension spaces are difficult to visualize, we use a three-dimensional projection to study individual particle trajectories. Specially developed interactive graphics tools were used to facilitate the search for strange attractor regions, and computations were done on a 128 processor hypercube computer. The system is dissipative, and the expected folding appears; trajectories fold in about the unstable stagnation points in the flow. These regions of folding are outside the principal vortices, and the folding regions appear to be bounded by the KAM surfaces that would be associated with the Hamiltonian ABC flow. Strange attractors are, observed in the steady-state trajectories. As the drag becomes very small, both the linear and nonlinear models approach the limiting case of ABC flow. While this seems reasonable, the ‘‘zero drag’’ limit is singular, in the sense that the six-dimensional phase space problem would have to become a three-dimensional problem in the limit of point particles. When released in a periodic or quasiperiodic region, a particle with a linear drag force retains trajectory regularity, even if it crosses a chaotic region. This was not true for the nonlinear drag model. The introduction of particles can be thought of as a perturbation of ABC flow, and as drag increases this perturbed flow exhibits increasing breakdown of KAM-like surfaces, leading to larger chaotic regions. Future work will concentrate on the particle perturbations to the base ABC flow, and more examination of the phase space projections which may possibly give information on basins of attraction.

PAWS: a performance evaluation tool for parallel computing systems

A description is given of PAWS (parallel assessment window system), a set of tools that provides an interactive user-friendly environment for analysis of existing, prototype, and conceptual machine architectures running a common application. PAWS consists of an application tool, an architectural characterization tool, a performance assessment tool, and an interactive graphical display tool. The application characterization tool provides a facility for evaluating the level and degree of an application's parallelism. The architecture characterization tool allows users to create, store, and retrieve descriptions of machines in a database. This approach permits users to evaluate conceptual machines before building any hardware. The performance assessment tool generates profile plots through the interactive graphical display tool. It shows both the ideal parallelism inherent in the machine-independent dataflow graph and the predicted parallelism of the partitioned dataflow graph on the target machine.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An interactive graphic tool to plot the structure of large sparse matrices

An interactive graphic tool to plot the structure of large sparse matrices

Decomposition; a strategy for judgemental forecasting

AbstractThis paper reports the results of studies concerning the accuracy and efficiency of time‐series extrapolation decisions made with the assistance of an interactive graphical tool called GRAFFECT. The tool facilitates the decomposition of the extrapolation task by permitting the serial decomposition of the cue data as the task proceeds. GRAFFECT uses an interactive graphical interface controlled substantially with the use of a mouse. The extrapolation task is divided into the following: (1) trend modelling and extrapolation, (2) seasonal pattern modelling, and (3) extrapolation from the noise residual series. As each component is modelled its effect is stored and the information is washed out of the cue series. The ultimate forecast is produced by automatic recomposition of the judgementally determined components. The results show a significant improvement in forecast accuracy over unaided judgment, resulting in a subjective extrapolation that betters deseasonalized single exponential smoothing.

A Design Tool for Distributed Man–Machine Interface of Real-time Power Systems and Power Plant Simulators

Development of man-machine interface (MMI) has been traditionally carried out writing a great deal of specific application software and, as a consequence, long development time with the associated high costs are observed. The interactive graphic tool described in this paper provides an opportunity for MMI designers to speed up the design of interactive and animated 2D graphics displays and, further, allows final users to customize the MMI to their needs.

A methodology for knowledge engineering using an interactive graphical tool for knowledge modelling

A basic feature of human nature is the propensity to construct boundaries which define territorial possession. Such assumed possessions are often jealously guarded by their owners, and a consequence of this primitive instinct is the emergence of subject specialists who exercise in-depth ‘lordship’ over their domain of expertise. For many years computer science has made attempts to relate to this phenomenon of expert intellectual property by developing mechanisms in software to emulate reasoning capability. Correspondingly this has resulted in the development of intelligent knowledge-based (or expert) systems, along with their attendant processes of knowledge elicitation, representation and exploitation. This paper attempts to define a context for knowledge engineering, the term being used to define spanning the void between domain expertise and the intelligent knowledge based system. It goes on to describe the systemic development of a particular solution to the knowledge engineering problem which is underpinned by a software environment called VEGAN (a Visual Editor for the Generation of Associative Networks). Many attempts have been made at bridging this gap, and VEGAN represents a significant aid to the knowledge engineering task, in the context of frame-based systems. Rather than attempt to create a unidirectional information path from expert to computer system (or knowledge engineer), VEGAN presents a common forum for discussion about, and exploration of, the expertise of the domain specialist. By doing so it helps the flow of information between the two parties. VEGAN represents an approach to a human-natured design of a software system which: 1. empathises with the ‘culpture’ of the expert, 2. provides a bridge between the expert and the computer system by shielfing the expert from the underlying complexity of the system, 3. aids the study of the organization of expertise, and thus induces further information.

Graphical postprocessing for 3‐D mesh quality evaluation

An important objective of 3‐D graphical finite element postprocessing is the facility to indicate to the engineer the accuracy of analysis results. The inclusion of mesh quality sensors permits a subjective evaluation of the adequacy of a single analysis being interpreted. For graphical approaches, both strain energy density gradients and discontinuities of unsmoothed responses and their gradients have proved to be effective sensors. Interactive graphical tools which can display discontinuity information effectively are described; these are essentially different from the ordinary methods used for the viewing of smoothed results.

Les apports respectifs des langages symboliques et de la cao en programmation des robots

SUMMARYA high-level robot programming language constitutes a general purpose interface for accessing the basic functional capabilities of a robot. On the other hand, CAD facilities give the possibility of using a subset of these capabilities in an easier fashion. In this paper, we show how a robot programming language and CAD facilities can be combined to obtain a robot programming system satisfying the need for generality, and allowing an easy connection with the basic robot programming functions. Such a connection is based on a “complete” simulator providing facilities for executing robot control programs on a graphic display, for describing manipulation tasks using interactive graphic tools, for simulating the physical world and its perception through sensors, and for displaying three-dimensional scenes as shaded pictures.

Development of a user friendly gate-level logic simulator

A design of a digital logic simulator is developed and presented. BASIC on an IBM Personal Computer using interactive graphics tools is employed to make the simulator easy to use. The simulator can handle gate level logic circuits, and can be used for both logic verification and fault testing. Efficient and correct simulation in a user-friendly environment was the main design objective. Concepts of interactive computer graphics are extensively applied to enable the drawing of the circuit. Menu structures have been used to simplify the interaction of user and computer. The foundation has been laid for a simulator that uses pattern recognition for circuit data acquisition. The simulator permits the verification of the logic of a circuit without fault. The design also includes provision for inserting delays and simulating to detect hazards. Test sequences to detect the presence of faults in the circuit can be generated using deductive simulation. The design provides a reliable basis for further research into logic simulation.

Interactive Tool with Transparent Real Time System Software for Process Control

An interactive graphical tool to define real time applications for process control is presented. Interactivity and graphical representation make the work of the user of the tool easy and the real time system software transparent to him. The task of the programmer is also simplified, roughly reduced to the writing of the controllers, all real time and communication aspects being solved.

Toward the design of an optimal filter for enhancement of dichromat monocular chromatic discrimination.

Based on Farnsworth's theories of color confusion and discrimination, "rose-colored" or "pink" filters such as the X-Chrom material of 0.16 mm in thickness or the Kodak Wratten no. 30 filter act as monocular chromatic enhancers for red/green color deficients by virtue of colorimetrically lengthening color space in a direction perpendicular to the dichromatic axis of color confusion. Using derived formulas for dichromat colorimetry, a set of representative isoluminant-isochroma spectral hues, and interactive computer graphic colorimetric tools, it is possible to determine an optimum spectrophotometric filter curve. Such a filter has minimal middle wavelength transmission and is optimal in terms of providing maximal monocular chromatic clues for discriminative tasks involving confused colors.

Modeling of experimental data with interactive graphics

An important aspect of modern chemical experimentation which is frequently overlooked is the rapid analysis of measured data. Computer programs used to perform this task are often laborious and noninteractive making the analysis process very painful and rigid. A good deal of reprogramming must be done to accommodate new models and analyze data sets. DMODEL is a program which provides the experimenter with flexible, highly interactive graphical data analysis tools. The program is extremely flexible and requires no reprogramming when new models are used. Models are entered into the program by typing them as input lines. Linear least-squares curve fitting can be easily carried out as can general interactive and exploratory data analysis.

Interactive microcomputer-based graphical tools for physician decision support. Aids to test selection and interpretation and use of Bayes' theorem.

Three microcomputer programs have been developed to give the practicing physician graphic aid in assessing the usefulness of obtaining a diagnostic test, to assist in interpreting the result after a test has been obtained, and to facilitate exploration of, and familiarity with, the use of Bayes' theorem in clinical practice. Each program uses a different representation for depicting the transformation of pretest to post-test probability produced by the various results of the test. Choice of representation depends on whether multiple tests or results are evaluated concurrently, on the probability range of interest, and on which model the user finds most intuitively appealing. A library of data on sensitivities and specificities of various tests and procedures can be used to select tests of interest from a menu, or data may be entered by the user.

OVIDE: A Software Package for Verifying and Validating Petri Nets

Managing with the increasing complexity of large scale systems, especIally real-time ones, become more and more difficult without the aid of a formal and powerful design methodology; the latter must be supported by automatic tools dealing with the resulting models in order to verify and validate these models. We introduce such a package based upon Petri-nets theory by which we can ensure the correctness of the specifications before the implementation phasis, mainly, concerning parallelism, synchronization, concurrency; OVIDE is an interactive graphic tool allowing different kinds of analysis: set of reachable markings, reductions, invariants,...