Tuesday, March 13, 2007

It is still early on the West coast. Somehow the reports of the lab on Friday made it look like problems were our fault. We did not have RF nearly the entire day. I am going to have to stand up and get people to stop bickering. Anyway we arrived late yesterday for lab hear in Redmond. The objectives are getting a little muddy. We will see if we stay the entire week.

Got an urgent message from the plus program yesterday during our lab session. It was a fluke that my email program got the email requesting my attention immediately. So I called the PLuS program. It was difficult to get my party. I was hoping just to say that I would call back in the morning here. Well instead I had to lay out my story in front of my lab workers. It was kind of difficult. I had to talk in a non-secure area. Well that is how this thing goes. The whole world needs to know your business. I was a little upset at first but this thing needs to get done. The PLuS program agent needs to be able to discuss my case with the DePaul administration to be able to get me special treatment. So I let this thing go. Talking to me during work in a load lab setting was a must this time. Standing in front of my co-workers talking about my life is just something I had to do.

Study has been difficult. I brought both laptops. After using the one I use for study yesterday I found out that I did not bring the power cord. Bummer. So I only use it for short burst and then turn it off. I would much rather use it to study with. It has all my tools that I need for study. I am making do with my lab laptop. I copied all of my needed files to a 60Gb thumb drive that I have. After that I am using emacs on my lab laptop to write notes etc. No acrobat and I have all my documents in PDF. Lucky cygwin has xpdf installed. It will have to do. Old school tools sometimes just save your life. I am not able to put my notes on my iPod. That is going to make it difficult to listen or read them off of it. The plane ride is a wash. I though I could do some review. I have my hand written notes but they are not as big a help as my study laptop and my iPod. Some people would be complaining about the small keyboard. That is the lest of my problems.

I have suspended the look at the architecture question. I have gone back to review the Chidamber and Kemerer paper question on OO metrics. I always have trouble remembering these guys names. They don`t rhyme with anything and I am having trouble with the word associations. I have rewritten my notes this morning and I have noticed I botched the LCOM metric. I think that I got it right now. relearning this one may be hard. I learned it wrong the first time. It was a good catch. It is a shame to spend so much time learning something and then think you have it but then have it wrong. Glad I had this experience with moving things around on different computers. It made me look at this stuff again and I found and error.

LCOM - Lack of cohesion in methods Lack of Cohesion in Methods. This is best illustrated with an example. Say we have three methods M1, M2, and M3. The instant variables used by the class methods are this I1={a,b,c,d,e} I2={a,b,c}, I3={x,y,z}. The intersection of I1 and I2 is non-empty but the intersection of I1 and I3 and the intersection of I2 and I3 are empty sets. The interaction between instance variable sets is termed the similarity between the methods. The larger the number the more cohesive the class. The count of the number of methods pairs whose similarity is 0 minus the count of the method pairs whose similarity is greater than 0 is LCOM. So in this case LCOM=2-1=1. LCOM is a measure of cohesion. A small number indicates greater cohesion of methods. Cohesion is desirable because it promotes encapsulation. Lack of cohesion implies a need to split the class into sub-classes. Low cohesion increases complexity, thereby increasing the likelihood of errors during the development process.

The part I got wrong was whether it was a high or low number that was desirable. I think I got it right now.

One month until the test assuming that I take it on the same day as the others.