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The Need for Context in Information Exchange

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  1. Abstract
  2. How it Used to Be
  3. Current Situation
  4. Why Can't we Just Cut and Paste?
    1. Why we Need Context
  5. The Challenge
  6. Next


This section introduces the concept of Context. When we exchange plant information with traditional methods we rely on context to retain meaning.

Information in ISO 15926 format is rich enough that we no longer need context to retain meaning.

How it Used to Be

When your humble author started his career in plant design, computers were not commonly used by designers and engineers. Drafting was by pencil on paper. Specifications were written with a typewriter. When information was transferred from one document to another the only choice was for a human to read the original document, find the value to be transferred, then write it by hand on the target document. If the target document was something like a specification it was usually given to a secretary for typing.

Transferring information from one storage location to another was cumbersome, but conceptually simple--you would take all the specifications and drawings, sort them into some logical order, perhaps bind them into books, and move them to the new location. Data turnover to the client at the end of a plant design project was similar to the last scene of the movie Raiders of the Lost Arc. A forklift carried a wooden box down an aisle of identical wooden boxes and put it on a pile. It sometimes took years for the owner to review all the boxes and categorize the binders of information.

No one really liked this (as in: "I really liked that piece of chocolate cake, may I have another!"), but that was just the way it was. It started to change when computers made their way into the design office. Binders of data sheets gave way to spreadsheets and databases and people started to think there might be a better way.

Current Situation

There have been some improvements, but in our work processes for plant design or plant operations, a large proportion of an engineer's activities still involve manually transferring information from one document to another. For instance, after the engineer chooses, say, an instrument, the only practical way to record the information about the instrument is to read the manufacturer's data, interpret it to decide which of the data values to transcribe, then figure out where to put the data values in the plant design system. Some of the operations are simple transcription, such as transferring a model number from one spot to another. But some involve calculation, such as changing from one unit of measurement to another. Others involve interpretation ranging from ignoring the data value altogether to decisions involving judgment, such as orientation or handedness. The work is done on a computer, but often the only real difference is that you do the typing yourself instead of giving it to your secretary.

Why Can't we Just Cut and Paste?

The obvious reason we can't just use a simple Cut and Paste tool is because the data values we want to transfer seldom map to the same (x,y) coordinates on any two data sheets. But beyond that, re rely so much on context to convey meaning that we cannot trust machines to make the right decisions.

Why we Need Context

Suppose you have to transfer information from one data sheet to another and you see this?


This means nothing. So you "back up" and look for more context.

Pressure: 1034

OK, so you know a bit more, but still nothing usable.

Pressure: 1034 kPa

Now you expect other values to be in SI units, but you still really don't know what is going on, so you "back up" some more.

Seal Flush
Pressure: 1034 kPa

You still have questions so you continue to "back up".

Tag No: P-101
Service: Chemical Injection to D-101
Seal Flush
Pressure: 1034 kPa

Now you are getting a clearer picture. When you "back up" and read the entire data sheet you can finally put the initial value, 1034, into context.

Centrifugal Pump Data Sheet
Client: ABC Chemical Company
Tag No: P-101
Service: Chemical Injection to D-101
Seal Flush
Pressure: 1034 kPa

Without context, we are lost.

The Challenge

When we exchange information without context we make it difficult for others to understand what we mean.

[TO DO: Robin Benjamin's cartoon about putting information in a bag]

Fig. X - Putting Information in a Bag

Figure X starts with someone having a bright idea. To achieve some business result he has to pass the information to someone else. If he just sends the information without context, he is just throwing it all in a bag and hoping the person on the other end can figure it out.

The reason information exchange worked in the past was that the only medium of exchange was with entire sets of data (for instance, a complete data sheet) where context is preserved. but the disadvantage is precisely that, we have to exchange whole sets of data and have humans interpret them. What we want is to be able to let machines exchange information directly without relying on context to retain meaning.

ISO 15926 accomplishes just that.

[TO DO: Robin's cartoon exchanging information with ISO 15926 bag]

Fig. Y - Putting Information in an ISO 15926 Bag

When we encode information in ISO 15926 format, we include enough context that other ISO 15926-enabled tools will clearly understand what we mean.


Mapping Databases is Expensive

When we want to exchange information between two software applications, the traditional way is to map the respective databases together. This is expensive and only done in a few high-value situations.



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