The Evils of Complexity Jules J. Berman, Ph.D., M.D. Han-Mo Koo Memorial Seminar Series Van Andel Research Institute Grand Rapids, Michigan Wednesday, April 25, 2007

In an informatics world, you can easily create levels of complexity that exceed anything encountered in the physical world. Complex systems are actually easier to create than simple systems. Complex systems, despite what anyone tells you, are unpredictable by computers.

Specifications versus Standards RDF versus XML Classifications versus Ontologies Ruby versus Perl

Standards aren't very standard Many competing standards Standards come in multiple versions Complexity bad for interoperability Standards are often someone's intellectual property Standards may contain embedded patents The uses of Standards can be patented

DICOM is the image standard for radiology, and there's an effort to migrate it to pathology. DICOM is highly complex, few people outside of radiology understand it. It uses old byte-designated format, nothing like currently used Web (metadata) technologies. If a medical image standard were developed today, from scratch, it would probably not resemble DICOM. Some of the most important scientific uses of DICOM cannot be pursued without infringing on existing patents.

Specifications are just descriptions of your data. A specification requires a common language for describing data (so that you and your computer can understand what it's trying to convey). Beyond providing a language for describing data, specifications give you enormous freedom to create and describe new and unconventional data objects.

All data can be specified using RDF, developed by the W3C. RDF files are collections of statements expressed as data triples <identified subject><metadata><data> “Jules Berman” “blood glucose level” “85” “Mary Smith” “eye color” “brown” “Samuel Rice” “eye color” “blue” “Jules Berman” “eye color” “brown” When you bind a key/value pair to a specified object, you're moving from the realm of data structure (i.e., XML) into the realm of data meaning.

RDF permits data to be merged between different files Medical file: “Jules Berman” “blood glucose level” “85” “Mary Smith” “eye color” “brown” “Samuel Rice” “eye color” “blue” “Jules Berman” “eye color” “brown” Merged Jules Berman database: “Jules Berman” “blood glucose level” “85” “Jules Berman” “eye color” “brown” “Jules Berman” “hat size” “9” Hat file: “Sally Frann” “hat size” “8” “Jules Berman” “hat size” “9” “Fred Garfield” “hat size” “9” “Fred Garfield” “hat_type” “bowler”

RDF provides answers to the following 4 questions (required for implementation). 1. How does the triple convey the unique identity of its subject? In the triple, “Jules Berman” “blood glucose level” “85”, The name "Jules Berman" is not unique and may apply to several different people. 2. How do we convey the meaning of metadata terms? Perhaps one person's definition of a metadata term is different from another person's. For example, is "hat size" the diameter of the hat, or the distance from ear to ear on the person who is intended to wear the hat, or a digit selected from a pre-defined scale? 3. How can we constrain the values described by metadata to a specific datatype? Can a person have an eye color of 8? Can a person have an eye color of "chartreuse"? 4. How can we indicate that a unique object is a member of a class and can be described by metadata shared by all the members of a class?

JPEG is an image format that is used by millions of people in all types of professions, including the medical profession JPEG can now be used without worrying about IP issues You can put any information you want into the header of a JPEG image (including an RDF document) so that specified clinical/pathological information can be conveyed with the image Because images non-physical, it is usually easy to interconvert image formats

Why not just use JPEG with an RDF specification of your image? You can always port to DICOM when you need to. See: http://www.julesberman.info/jjb_gwm.pdf More on specifications at “Specified Life” blog: http://julesberman.blogspot.com/

Classifications versus Ontologies Our similarities are different – Yogi Berra