Models and modeling: be careful and use your imagination

When not soldering, engineers continuously deal with models when analyzing, designing, and implementing. There are two phases in modeling: utilization, and creation. Model utilization is common practice, and does not necessitate further comment other than "make the right choice and use the model carefully." The tutorial addresses the first phase briefly and shows how erroneous results may occur when care is not exercised. The second phase is much more subtle: it requires delicate measurements, extreme perception, and/or excellent imagination. Memnristors and memnristive systems, a perfect illustration of "using imagination," are presented and discussed at length. Their recent realization as a nano-chip by HP is a very good example of "history repeating itself," and proof of how "an electrical element that was postulated almost fifty years ago to exist, became a reality." The tutorial concludes with some reactions to and comments about this new device.