Friday, August 17, 2018


I'm starting a new semester so I can't help but think about grading. I believe that grades serve the useful purpose of forcing students to work harder than they otherwise might. I think, however, that they are of limited usefulness in actually measuring anything. If a question shows us that some item of knowledge has been acquired by the student what is the likelihood that that knowledge will be retained a year from now? or two years from now? And no two items of knowledge will be of equal usefulness. How can we estimate that? And some items of knowledge will prove useful for one student but not for others. And these things will all change as time passes.

It would be interesting to search out roughly equivalent cases in the casebases from various Asa H agents and compare their vector utilities.

Wednesday, August 15, 2018

Machine learning

I just got a new pair of Widex EVOKE hearing aids from Denmark. I was anxious to try out the machine learning feature. I found it hard to make the “A” versus “B” choices. Should I prefer louder (more signal) but with noise or should I prefer softer (less signal) but with little background noise? I also found that one of the two aids stayed connected to my iPhone but the other one lost connection.

Tuesday, August 14, 2018

Learning what to ignore (attention again)

Humans learn to ignore stimuli that are not "important" to them. The ringing in my ears for example. In A.s.a. H. value/utility is typically a vector quantity. One component of this vector utility is a measure of how frequently A.s.a. sees that particular case reoccur. Another component of the vector utility measures how strongly that particular case is associated with "food," "reproduction," "pain," "health," or the like. Once A.s.a. H. has recorded a good number of similar cases it is possible to do a sensitivity analysis for each of the inputs to the cases in this cluster. One can identify any input that does not have a significant influence on the output (or next portion) of that case (or pattern sequence). One can then suppress the output from that case/cluster to the next level in the A.s.a. hierarchical memory as being common but unimportant. A given case ("stimuli") may turn out to be common but may not be important and once so identified can be ignored.

Sunday, August 12, 2018

More reliability issues

Admittedly I use mostly commodity computers in order to save money. I frequently use USB flash drives to store A.s.a. H.’s casebases and to store and transfer activation* from one level in the hierarchical memory to another and from one computer in the network to another. Sometimes one of the drives is not recognized. This is a random event and I’ve typically managed to fix it but it is a nuisance.

* I want to be able to examine the concepts being created and used.

Friday, August 3, 2018

A.s.a. H.’s early model of the world

Depending upon the environment its used in and the tasks it’s given an A.s.a. Agent typically begins learning a model of the world composed of concepts/sequences like:

near=>far, far=>near  (motion)
motion=>collision  (obstacle)
light=>dark, dark=>light  (day and night)
change in illumination angle
hot=>cold, cold=>hot

Thursday, August 2, 2018

Student evaluations

I have been critical of the use of student evaluations of instruction. (See, for example, R. Jones, Bull. Am. Phys. Soc., vol. 40, page 968, 1995) The July 2018 issue of American Journal of Physics has an article by Lee, et al, which states: "...Student Evaluations of Instruction do not correlate with conceptual learning gains..." and "...grading leniency by an instructor (i.e., giving easy A grades) does not correlate with increased student evaluations of instruction." (Am.J.Phys., vol. 86, no. 7, page 531, 2018) About 30 years ago I tried to tell our administrators and regents this but they would not listen. Some years back (~20?) I had a student admit to me that her fellow students would lie on student evaluations in order to "get rid" of or at least "make trouble for" professors they didn't like.

Thursday, July 26, 2018

Matches and lighters

Maybe we shouldn’t compare reusable rockets with airplanes. Reusable rockets need parachutes, wings, extra fuel, etc. and added design and maintenance costs. Their economics depends upon the number of launchs that can be expected over time. Just like we still manufacture and use both lighters and matches there may be room for both reusable and non reusable rockets in the world’s fleet. Certainly military rockets like ICBMs will be single use. And when they are decommissioned why not use them as space launchers as we have in the past?