Deterministic Operation Research Model Question. Please help. I\'m using LINDO O
ID: 673675 • Letter: D
Question
Deterministic Operation Research Model Question. Please help. I'm using LINDO
Often, a tooling machine is outfitted with different tools during a day to help produce different parts. There is a delay incurred during the changing from one tool to another. Suppose your tooling machine has eight different tools that are used during a given day. The matrix below gives the delay time t_ij (in minutes) of changing from tool i to tool j. Assuming that the order used during one day's operation is the same for the next day, and that once the final tool is used the operators must reinstall the first tool used before their shift ends, find the order the tools should be used on the machine in order to minimize the total changing time.Explanation / Answer
Model
The term, model, is itself challenging. There are many ways to use the word, two of which are particularly relevant for this discussion. The first meaning is “mathematical model, as a decision-making tool”. This is the one I am familiar with from years of teaching Operations Research. The second way is “way of thinking or representing an idea”. Or something like that. It seems to come from psychology.
Many models perform useful functions. My husband works as a land-surveyor, and his work involves making models on paper or in the computer, of phenomenon on the land, and making sure that specified marks on the model correspond to the marks placed in the ground. The purpose of the model relates to ownership and making sure the sewers run in the right direction. (As a result of several years of earthquakes in Christchurch, his models are less deterministic than they used to be, and unfortunately many of our sewers ended up running the wrong way.)
Our world is full of models:
When teaching mathematical models in entry level operations research/management science we would spend some time clarifying what we mean by a model. I have written about this in the post, “All models are wrong.”
In a simple, concrete incarnation, a model is a representation of another object. A simple example is that of a model car or a Lego model of a house. There are aspects of the model that are the same as the original, such as the shape and ability to move or not. But many aspects of the real-life object are missing in the model. The car does not have an internal combustion engine, and the house has no soft-furnishings. (And very bumpy floors). There is little purpose for either of these models, except entertainment and the joy of creation or ownership. (You might be interested in the following video of the Lego Parisian restaurant, which I am coveting. Funny way to say Parisian!)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.