RightChain Routing Transcript

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That's actually a constraint. This is not something you minimize or maximize. You meet a stipulated number of customers. You have [00:05:30] to visit that number of customers. That's a constraint. Meet all time window requirements. That's a constraint. You executed all the pickups and deliveries. That's a constraint. You're not trying to minimize or maximize that. That's something you have to do. Minimizes fuel consumption. Anytime you see that word right there, you should think that's an objective. [00:06:00] Minimizes the driver's time, minimizes the elapsed time meets hours of service requirements, meets safety requirements minimizes damage. That's an objective. Minimizes the probability of theft and hijacking. Dr. Frazelle (06:25): That's an objective. Maximizes the cube utilization. Balances [00:06:30] the workload. That's going to be a constraint. Meets the traffic guidelines, does not exceed speed limits. That's a constraint. It's not being adhered to, but does not exceed weight limits, does not violate one way. Streets minimizes wear and tear on equipment. I hope you're starting to pick up the difference. Now let's see if we can put that thing in the form of an optimization statement. I'm not doing this just [00:07:00] because we're at Georgia Tech. This is the hub of optimization in the whole world. What I have found is that if you look at ways to solve problems, especially in logistics, this is one of the best ways to solve it. We have an expression in our firm that says, don't philosophize optimize. Put it in this format, run the numbers with it and you usually wind up with a better solution. Let's try this. Let's make a table with constraints. [00:07:30] One was we visit every stop, make every pickup slash delivery. The hours for the route have to be less or equal to the hours that come from [00:08:00] government regulations. Now we're getting a little fancy less or equal to this is a good one. How could you write meets safety requirements in this form? You're going there. You're getting there. A, you might say that the probability of an accident is less than or equal to whatever target that you established. Dr. Frazelle (08:30): [00:08:30] You could also have the severity of the accident is less than or equal to some target. You can even multiply those things together that the probability of the accident times the severity of the accident is less than or equal to some target. That's how you start to convert these things [00:09:00] that are in laws and words into numbers. Can you calculate the probability of an accident on a route? Absolutely. And can you track the severity of accidents on a route? Absolutely. Okay. You want the probability of theft to be less than or equal to a target that's established speed limits. Dr. Frazelle (09:29): How can you enforce [00:09:30] speed limits in routing? You can literally force it with governors, with electronic speed regulators, and there's all kinds of things you can do there. I was driving up in Ohio one day this summer and there was a motorcycle doing wheelies in the middle of the interstate, so I called 9 1 1 and gave him the license plate and said, oh, you're not the first one who called? We have several officers on the way. That's how you start [00:10:00] to build a set of constraints. Now, let's try an objective function. One characteristic of a good objective function is the units of measure have to be the same. I can't say minimize hours plus, minimize gallons

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