Frustrated systems: A love-hate relationship
By Dick Morley
Have you ever heard of frustrated systems – not in the social or emotional sense, but in the scientific sense? Academics suggest that frustrated systems exist everywhere. In the simplest sense, a frustrated system occurs when the system has to make many elements within the system happy simultaneously, but the system cannot change itself or the conditions to make everybody optimally happy. Some analogies may be necessary.
Feng shui is an ancient Chinese system aimed at optimizing the location of components (e.g. rearranging furniture) to please heaven and earth so that all are satisfied. This includes the inhabitants, the flow and the karma. It is interesting that this attempt to optimize the physical environment is ongoing and seems to be an endless high-cost endeavour.
Another analogy is the Morley family reunion. There is no way that we can put together a family reunion that satisfies all attendees. If we satisfy one person or group, the other groups are less happy. The degree of happiness is a constant across the entire system, independent of how we relate components (in-laws included) at a New Hampshire reunion. As a practical matter, I have two brothers, and we each take turns organizing the reunion.
Let’s get a little more into the meat of this subject. Imagine a pool table set up to explain the idea of frustrated systems. If you distribute as many golf balls and marbles as you can across the table, there will still be empty space. No matter how you move the marbles and golf balls, the empty space remains a constant. You are frustrated. If, on the other hand, you have cubic boxes all the same size, these can be put into an arrangement on the pool table that is not frustrated.
One more example: Honeybees have a cellular nest structure of hexagons. These pack well and do not leave open, unstructured space. We may think that this is an optimal system, but is it really? If the honeybees used square cells, they would still have full utilization of the acreage. Having both types, however, leaves open areas and unused total space, independent of how you arrange the hexagon or square elements. The honeybees are frustrated.
Most of the work done by analysing systems as frustrated systems occurs in atomic physics and biological cellular structures. There is no need to go into it here. You can find out more by surfing the term “frustrated systems” online. So why am I discussing this in an automation magazine?
Components in a SCADA system must speak with each other. A formal definition of a frustrated system suggests that when components in the system communicate, they have to make decisions as to the route taken to connect to nearby elements. If we buy components that are locally optimal, we make the interaction between those optimal components difficult and end up with “shapes” that do not adequately cover the system demands. This would imply that we should buy equipment from a single vendor, which would reduce physical frustration in the system. (As an aside, when we first invented the programmable controller, major chemical companies would pick one vendor for one system and a competing vendor for the next, but would not mix vendors inside a single system – better coverage over the Shannon space.)
This also applies to software, open systems and applications. Having internal operating systems compete for system allocations on a real-time dynamic basis is clearly a no-no. A good understanding of frustrated systems is to build applications that are clearly defined such that they all have a look-alike connection. To some extent, we can visualize the applications in an iPod as honeybee hexagons. What you put in one cell can vary (queen, worker, soldier), but all cells look alike. Us geeks don’t like that. We have to learn to deal with systems on a fundamental basis and not the local optimization.
A further example is my town’s Internet system, which we host for some portion of the town. My local communication techie wants to go to higher and higher speeds for each user. I do a lot of distance teaching and must have a robust system. Since we live in ski country with many pine tree dipoles, I can’t optimize each independently. I want to have service always, at a reasonable bandwidth, while the techies want infinite bandwidth that runs less reliably. Yeah, I know this is an exaggeration, but bear with me.
Now let’s talk about non-Lean manufacturing systems. The cost of the factory is not the cost of the product. Optimizing the factory to localize cost reduction can impede time to market and lust-to-dust costs. Lean should include the entire lust-to-dust concept. We need frustrated factories.
The message here is to optimize the system with the understanding that you can’t. You can move the various blocks around to apparently achieve local optimization, but only by penalizing the surrounding environment. Stay frustrated.
Dick Morley is the inventor of the PLC, an author, speaker, automation industry maverick and a self-proclaimed ubergeek. E-mail him at email@example.com.