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  • By Harry Kortnicki
  • In Blog
  • Posted 30/04/2021

In this guest blog, long-time WITNESS user Harry Kortnicki reflects on the role simulation has played over his long career as a mechanical engineer. 

I began my career as a Mechanical Engineer at a global Engineering and Construction company in 1975.Soon after I began my engineering career, I became involved with the application of Discrete Event Simulation (DES) in the design of material handling systems. In the late 1970’s and early 1980’s, I was using FORTRAN on mainframe computers for design of bulk material handling conveyors. With the introduction of PC’s in the early 1980’s, I started using DES character based programming software on PCs. I was one of the early users of WITNESS when it debuted in the early 1990’s as the first DES software to operate under the new MS Windows graphical interface.

The graphical interface provided in WITNESS had two major benefits for users worldwide. The first benefit was in verifying DES models during development. Prior to the graphical interface provided in WITNESS, users only had data produced by their models as a means of confirming that the operating logic of their models was realistically simulating the physicals systems being modeled. The ability to stop a model at a desired break point and visually confirm its operations provided a much faster and more confident means of verifying models. The second benefit for users was in presenting the operation and results of their models to management and clients. The ability for a client to see graphical elements moving across a plant background representing the operation of their plants conveyed a much higher level of confidence in the model results.

Although my company’s historical market had primarily been the oil and gas industry, it is now diversified into a very broad range of industries. This diversification has provided me with the opportunities to use WITNESS for projects in many of the company’s worldwide offices. With the advance of global networks and teleconferencing, most of these models were developed for other company offices without my need for extensive travel. The range of industries and applications in which I’ve used WITNESS include:

Oil & Gas

  • Oil Refinery Reliability Analysis
  • Natural Gas Processing
  • Natural Gas Storage & Pipeline Operations
  • Oil Sands Extraction and Processing


  • Port Management & Tanker Loading


  • Ore Processing
  • Ore Concentrate & Mining Supply Logistics
  • Aluminum Coil Processing
  • Copper Refining & Logistics


  • Nuclear Waste Processing
  • Spent Fuel Storage
  • Uranium Fuel Enrichment
  • Nuclear Weapons Production


  • Solar Panel Reliability Analysis
  • Municipal Waste to Ethanol Production

These range of these applications certainly demonstrate the versatility of WITNESS beyond its initial focus on conventional manufacturing plants. This versatility has helped create interesting, challenging and fulfilling experiences over my 45 year career, and I’m proud to reflect back on the value I’ve helped our clients realize through the use of WITNESS and discrete event simulation. 

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