Tag Archives: operations research

Ant Colony Optimization – Coded and Testing

A few months ago I wrote a post about my interest in Ant Colony Optimization (ACO) and my goal to add it to my metaheuristic bag of tricks. I finally was able to code up a version of an ACO … Continue reading

Posted in Uncategorized | Tagged , | 1 Comment

Piecewise Linear Objective Functions in Mathematical Models

Sometimes when formulating a LP or MIP, you run into the scenario where it is better to have several small occurrences of a bad event (or good event) rather than a single, larger occurrence. Consider a basic machine scheduling problem … Continue reading

Posted in Uncategorized | Tagged , , | 3 Comments

Additional Constraints Can Sometimes Help Performance

In linear and mixed integer programming, constraints often have a bad reputation. If a model is a family, then the constraints are the parents – making sure everyone does their homework, brushes their teeth, and in general obeys the rules. … Continue reading

Posted in Uncategorized | Tagged , , | 2 Comments

Ant Colony Optimization – Optimizing the Search for Food

When I saw that the latest Informs blogging challenge was OR and food, I immediately thought of the diet problem and minimizing grocery bills while maximizing nutrition (a knapsack problem, perhaps). But I also thought about Ant Colony Optimization which … Continue reading

Posted in Uncategorized | Tagged , | 4 Comments

My New Year Resolution – Take a Second Look

In thinking about new year resolutions and how I can improve my model building in 2012, I looked back on some of the ways I made big improvements to models I developed this past year. I spent the majority of … Continue reading

Posted in Uncategorized | Tagged , , | 1 Comment

Optimizing Your Transportation Network can Reduce Your Carbon Footprint

In the past few years, I have worked on optimization models for different sectors of the Transportation industry that all have one thing in common: the goal always includes minimizing non-revenue trips, either explicitly defined as the objective function or … Continue reading

Posted in Uncategorized | Tagged , , , | Leave a comment

When the Data Changes Before the Model Even Finishes Solving

This month’s INFORMS blogging challenge topic is OR and analytics. Last Wednesday I was thinking seriously about this topic, in particular how OR and analytics, although separate fields, can benefit from each other, when I saw Michael Trick’s post outlining … Continue reading

Posted in Uncategorized | Tagged , , | Leave a comment