Tribute to Andy Sage, and a new taxonomy of model attributes

First let me render some recollections about Andy Sage, a wonderful human being to whom those of us calling ourselves system engineers owe a great deal. My first connection with Andy was in regard to IEEE Transactions. I had been Editor of IEEE Transactions on Human Factors in Electronics, starting around 1966. That publication changed its name in 1970 to IEEE Transactions on Man-Machine Systems. There was also an IEEE Transactions of Systems Science and Cybernetics existing from about 1964. In the early 1970s it was decided to combine the two IEEE Groups and hence their transactions as well, the combined publication being IEEE Transactions on Systems Man and Cybernetics. Andy Sage was chosen Editor of that new Transactions and served in that role for many years, doing an outstanding job. As is no doubt mentioned in other papers in this volume Andy took on a great many other editing and book-writing tasks, in addition to becoming the founding Dean of the School of Engineering at George Mason University. I always held Andy in the greatest esteem in terms of his energy, organizational skills and fairness. The results of his efforts were always of the highest quality.