Newer Publications

The Rime of the Ancyent Programmer
Association for Computing Machinery

"How one programmer's career, set adrift on the raging seas of technological change, has been tossed by the winds of fate."

Codysseus - Κοδυσσευς
Sys Admin Magazine

"A Geek Travesty by Erudil"

Concerning Interruptions
IEEE Computer Society

There's a harmless sounding, four-syllable question that causes much wailing and gnashing of teeth among programmers: "Got a minute?" I cringe if I hear those words while I'm coding, because by the time I've looked up and answered "No!", the damage is often already done.

Musings of an "Old-School" Programmer
Association for Computing Machinery

"A traditional style of software development can be just as productive as a more modern approach"

Debugging Heterogeneous Distributed Applications
Doctor Dobb's Journal

"A reliable logging system for recording software events"

A Web-Based System to Gather and Distribute Specifications for Wind Tunnel Tests
American Institute of Aeronautics and Astronautics

A web-based system to gather and distribute specifications for wind tunnel tests has been created at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. The test specification program has been written to provide a simple method of collecting and disseminating the information required by the technical support staff to properly install, configure, and conduct wind tunnel tests. Relying on Open Source Software (Linux, Apache, and Perl) for its implementation, this application takes advantage of three common technologies (the Web, email, and PDF files) to create a tool that is both powerful and easy to use.

Offline Programmatic Generation of Web Pages
YAPC

Making Servers Dynamically Configurable
The Perl Journal

"The best way to provide for (...) changes, is to make the servers dynamically configurable, rather than the traditional method of requiring the application to be stopped and restarted with new command-line or configuration-file values."

Offline Programmatic Generation of Web Pages
USENIX Association

As programmers, when we need to provide Web-accessible information, two methods usually come to mind: a static one - creating Web pages in an editor or Web development tool; and a dynamic one - creating CGI programs to generate HTML. There is however a third, often overlooked, option: offline programmatic generation of Web pages (OPG). By OPG, I mean writing programs to generate HTML documents at the time and location of your choosing, as opposed to CGI programs where the pages are generated at access time, on the computer hosting the Web server.

An Overview of the ISTARI System
National Research Council Canada

Limited distribution

Time-Lapse MPEG Animations
Doctor Dobb's Journal

"Generating time-lapse animations starts with acquiring and storing images, then combining them in a single file."

A Web-based Environment to Support Aerodynamic Testing
Institute of Electrical and Electronics Engineers

Over the past several years, a web-based environment to support aerodynamic testing has been under development at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. As a mechanism for interacting with users, the World Wide Web offers one significant advantage over other, more traditional techniques: it is "easy". More specifically, it is easy to use, easy to distribute, easy to expand, easy to develop for, and easy to maintain. The web-based testing environment at the Aerodynamics Laboratory currently consists of five primary applications, nine secondary applications, and a large number of web pages containing documentation, system status, and links to outside information. These resources may be accessed via "home pages" created for clients and staff. The five primary applications are a data file viewer, a plotting system, a configuration file editor, a dynamic data display system, and an event recording and display system. The secondary applications include a units conversion calculator, an electronic test specification form for use by the engineering staff, and several software support tools for use by the IT personnel.

Automatic Generation of Time-lapse Animations
  • yapc::Canada - Carleton University, Ottawa, Canada, May 2003
YAPC

A simple system for the automatic generation of time-lapse animations has been created at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada (NRC). The system consists of two small Perl programs and a static web page, and relies heavily on two open source software packages: LWP::Simple, and ImageMagick. The first program, tlget.pl, runs for several hours each weekday and is responsible for the periodic acquisition (and storage) of images from a web-based camera. The second program, tlmpeg.pl, is responsible for the conversion of groups of JPEG format images into MPEG format animations. Typically, tlmpeg.pl is executed each weekday night, and generates three animation files, one from the past day's images, one from the past week's images, and one from the past month's images. A static web page has been created to display the image most recently acquired by tlget.pl, and to provide links to each of the three animation files most recently generated by tlmpeg.pl.

A Description of the Software for a Cockpit Video Security System
National Research Council Canada

Limited distribution, classified

A Configuration File Editor for a Wind Tunnel Data System
YAPC

A configuration file editor has been created at the Aerodynamics Laboratory of the Institute for Aerospace Research. This program allows the clients and staff of the 2m x 3m wind tunnel to modify the files that control the data acquisition and reduction processes. Because modifications to the large quantity of "C" code that interacts with these files were deemed to be impractical, a solution has been devised that is compatible with the legacy file format, while providing the benefits of a web-based interface.

Generating JavaScript from Perl
Doctor Dobb's Journal

"The techniques Stephen presents here help you provide users with a better UI and reduce the load on web servers."

Wind Tunnel Testing Technologies at IAR - A Series of Lectures Delivered to Universiti Technologi Malaysia
  • With Dr. S.J. Zan (senior author), et al
  • Institute for Aerospace Research, Laboratory Memorandum LM-AL-2002-0020, Mar. 2002.
  • National Research Council of Canada
National Research Council Canada

Limited distribution

Open Source Software at the Aerodynamics Laboratory
Linux Journal

"Aerospace companies are the biggest customers of the Aerodynamics Laboratory of the Institute for Aerospace Research, Canada. A typical aircraft experiment includes 500,000 measurements resulting in 500Mb of data. That information needs to be accessed and manipulated by clients and engineers. Steve Jenkins tells us how he uses open-source software to make it all possible."

Run-time Generation of JavaScript Code by Perl CGI Programs
YAPC

Run-time generation of JavaScript code by Perl CGI programs is a technique that has been used with considerable success at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. After a brief introduction to the basic concept of dynamic code generation and its role within the data acquisition, data display and test-control software of the 2m x 3m wind tunnel, four specific examples will be presented each highlighting a different application of the technique. The first and simplest example will show the generation of trivial one-line JavaScript programs. The second example will show the run-time generation of JavaScript functions that modify groups of HTML checkbox elements. The third example will cover form validation in the browser, complete with pop-up alert boxes and dynamic images to prompt the user. The final, and most complex case, will show the creation of JavaScript code that produces dynamic behavior in HTML forms. These examples not only demonstrate the primary benefit of the technique - a more interactive user interface - but also show the secondary benefits: reduced load on both the web-server and web-client computers.

Using Perl to Create Web-based Software Tools for Wind Tunnel Testing
American Institute of Aeronautics and Astronautics

Over the past four years, significant effort has been expended to create and implement several web-based software tools for the 2m x 3m Low-Speed Wind Tunnel at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. These tools have been implemented through the use of three large open-source projects: the Perl programming language, the Apache web server, and the Linux operating system. Five individual software systems have been created: plotting; configuration file editing; data file viewing; event logging; and a dynamic data display. This paper briefly describes the reasoning behind the decisions to use Perl and the World Wide Web, as well as the function of each of the five tools and shows examples of the web pages used to interact with them.

A Dynamic Data-display System Using CGI and Server Push
  • Yet Another Perl Conference - Carnegie Mellon University, Pittsburgh, PA, June 2000
YAPC

A dynamic data-display system using CGI and server push techniques has been developed for the 2m x 3m Low-speed Wind Tunnel at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. The data acquisition environment in which the system runs dictated two fundamental design criteria. The first requirement was the need to simultaneously provide the users of several PCs and Unix workstations with a columnar text data display that could be updated dynamically and also retain a specified number of updates for comparative purposes. The second requirement was the need to accept asynchronous data from reporting processes on multiple remote computers. An additional design consideration was the adoption by the software development staff at the Aerodynamics Laboratory of a general policy of using open standards and open-source software, wherever possible. By using Perl to implement traditional client-server methods for gathering, processing and distributing the data to be displayed, and by using CGI.pm to implement the user interface, a simple, robust and platform-independent system has been created that meets the design criteria and also provides additional functionality. This paper is intended to present an overall description of the display system and its operating environment, as well as specific details of the design and implementation.

A System for Recording and Viewing Events in a Distributed Data Acquisition Environment
  • Yet Another Perl Conference - Carnegie Mellon University, Pittsburgh, PA, June 1999
YAPC

A system for recording and viewing events in a distributed data acquisition environment has been developed at the Aerodynamics Laboratory of the Institute for Aerospace Research, National Research Council of Canada. The system has been designed to capture and record asynchronous events generated by multiple programs and users, and to allow a simple, intuitive and platform-independent method of examining events of specific interest. The ease of use from the perspective of both software developers and end-users alike leads to rapid acceptance and utilization of this system. The result is the existence of an accurate record of the events occurring during a wind tunnel test that is of great value in carrying out the task of finding and eliminating problems caused by inconsistencies in software, hardware or operating procedures. This document is intended to provide an overall description of the system as well as specific details of its implementation.

A System for Logging and Displaying Software Events in a Distributed Computing Environment
  • Institute for Aerospace Research, Laboratory Technical Report LTR-A-031, Jan. 1999.
  • National Research Council of Canada
National Research Council Canada

Limited distribution

A Web-based System for Plotting Wind Tunnel Data
  • Institute for Aerospace Research, Laboratory Technical Report LTR-A-022, May 1998.
  • National Research Council of Canada
National Research Council Canada

Limited distribution

Older Publications

Large-Amplitude High-Rate Roll Experiments on a Delta and Double Delta Wing
American Institute of Aeronautics and Astronautics

A comprehensive wind-tunnel test program on both a 65° delta an 80°/65° double delta wing model has been recently completed. The program included static and dynamic force tests. A brief description of the various experiments is presented, as well as results that demonstrate the value of the previously proposed "hypersurface" representation of aerodynamic loads in the non-linear and unsteady regimes.

A Method for Non-linear Flight Mechanics Simulations
Institute of Electrical and Electronics Engineers

The severely non-linear and unsteady flow regimes encountered by modern high-performance aircraft lead to serious difficulties in predicting their dynamic behaviour. An approach for conducting flight mechanics simulations, intended to avoid some of the limitations of the currently used locally linearized models, is described. Single degree-of-freedom (roll) simulations based on wind-tunnel data obtained with a novel dynamic testing technique are compared with motion time histories obtained in free-to-roll tests.

Instrumentation and Other Issues in Non-linear Dynamic Testing in Wind Tunnels
Institute of Electrical and Electronics Engineers

A new wind-tunnel technique, specifically developed to measure instantaneous values of the aerodynamic loads acting on a moving model in terms of the corresponding values of the motion variables is briefly reviewed. The technique is particularly useful to obtain aerodynamic data for extreme flight conditions, where severe non-linearities render the data obtained from traditional dynamic tests inadequate as the basis for the modeling of aircraft behavior.


For more information contact Erudil@Erudil.com
Copyright © 2007 by Stephen B. Jenkins
Updated 2007-05-01
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