live as a pig at the end of 2006

Maybe florida is too warm. I caught the cold right back to Bethlehem. Now everyday, I sleep, eat, sleep. Today, I finally try to do something different and played monopoly. As usually, I defeat computer players with my perfect preformance in stock market. If it were real money, oh...

Hope tomorrow 2007, I can recover and go back to normal status.

Two OR applications in Florida Trip

The first one is queueing theory.
When I was in Magic Kingdom, I found an interesting application of queueing theor - Fast Pass. The procedure is the following. 1) When you see a waiting line is quite long at one attraction say Space Mountain, you can insert your ticket in one machine to get a fast pass which indicates you return during the specific time usually one or two hours laters. 2) Then when you return after playing other stuffs, you can go through the fast pass line.
There are several key points. 1) Once you get your fast pass for one attraction, you cannot get fast pass for another attraction until your current fast pass expire. For example, if I get fast pass for Space Mountain from 1pm to 2pm. I can only get fast pass for Splash Mountain after 2pm. 2) The number of fast pass in one attraction must be limited. Since the available time for the fast pass is different at different attraction, the hotter the attraction is, the longer time difference between available time of fast pass and current will be. In the last attraction-Jungle Cruise we go at 5pm, its fast pass is unavailable. We need to wait 40mins to play.
The decision to make for the visitor. 1) What is the sequence of attraction I should follow. 2) Which attraction should I get the fast pass.
The decision to make for the Theme Park. 1) How much fast passes to available at each attraction and each time periods.
Game theory might not be suitable in this case. Probably, something like priority queue plus abandon and other customer behavior can be used to formulate the problem.

My experience of fast pass in Unversal Studio at CA is different. We got the fast pass after we experienced a half hour technique difficulty at Jurassic Park. Then we can get into fast pass line for every attraction. But actually, you need to spend 30$ to get one fast pass. So the decision for the theme park is how much fast pass to offer and how much to charge.

The second one is network flow. It is very wise decision to buy a GPS just before this trip. We don't need to print every map. And we can avoid the traffic jam in the high way by going through the local. It was very crucial when we tried to catch up our flight back. And the calculation of route is very fast, it is much faster than O(A) I learned last semester. But actually it can only calculate the route from two points. If I want to go several points a day, I need to manually choose the sequence of points I need to goal. If GPS can provide the function of solve small TSP problem such as 5 points, it will be wonderful. Since real map satisfy triangle inequality, there is heuristic to get solution within 1.5 time of optimal solution. So the calculation time won't increase a lot.

Final week is over

This should be my second last final week. Now I am enjoying the final quarter of game between Rocket and Laker, two of my favorite NBA teams. As usual, I don't have mood to study once there is two or three weeks to final week. This year this mood is especially strong cause Rocket comes strong this season. After I finish the trip to Florida, I should use my time sheet again to do my time management which I haven't done after INFORMS.

Textbook: Convex Analysis and Optimization

Today I want to search how to prove a function is unimodal. I get the following book, Convex Analysis and Optimization by Dimitri P. Bertsekas. What I like Dimitri P. Bertsekas most is that he always post his class slide accompanying his book. Another example is his book Dynamic Programming and Optimal Control.

How to Bring Our Schools Out of the 20th Century

Time shows the views how American people would like education to be in the 21th century. Let's compare to Chinese education I received

• Knowing more about the world. (China: Almost all high school will teach English and we learn history of world. USA: where fewer than half of high school students are enrolled in a foreign-language class and where the social-studies curriculum tends to fixate on U.S. history.)
• Thinking outside the box. (This is weakness of Chinese education. But it seems with no child left behind(NCLB), American goes to Asian type education more and more.)
• Becoming smarter about new sources of information. (This one is hard to tell. Only thing I can say is that more knowledge I have, the smarter I can deal with new information)
• Developing good people skills. (This is also a weakness of Chinese people. There is a saying that 'three monk don't have water'. And I found the counterpart in English:Everybody's business is nobody's business. So it is also a problem in USA. I think it is due to how people get measured. Maybe in USA, there is fairer measure of team work than China. For example, almost every teacher ask students to put down name of people who help their homework)

One surprising thing is to see the following question for a second grade student: How many ways can you combine nickels, dimes and pennies to get 20¢? This question can be solved by recursion. It would be interesting to see how teachers tell students the way to solve the problem.

Three Major Assumptions in Marketing and my customerized assumptions for MS/OR

It is interesting to know the major assumptions in marketing.

• The customers are complete. It means that they can compare any two items. 'complete' here is similar to the definition in the math. There is no hole
• The customers are transitive. If the customer prefer A to B and B to C, then they prefer A to C.
• The more choices, the better.

Is any major assumption in MS/OR field? I never see anything like those three major assumptions in Marketing. But we can have similar one.

• The decision makers are complete. It means that they can compare any two solutions.
• The decision makers are transitive. If the decision makers prefer A to B and B to C, then they prefer A to C.
• The larger decision variable sets, the better result the decision makers can get.

Don't need to get up at 8:30 every weekday now

This week is the final week. During the whole semester, I have classes beginning around 9:00 everyday. Now everything is over and I can get up whenever I am awake.

Bless T-Mac!

Although YM got 23pt in the fourth quater and hit the clutch shot, it cannot make me happy. It is because T-Mac got hurt his back in today's game with Wizards. Rocket has very good beginning of this season. All we need is to wait for T-Mac get recovered with 80% degree compared with his status vs Dallas during the playoff at 04-05.

I really like T-Mac this season. He changes his style from scoring to controling the game. His basket IQ is a key for the success of Rocket. With T-Mac and YM, I can spend almost 3 hours every game day. But now it seems Rocket will go to lottery again with this injury, even though YM has very strong performance this season. Let's hope it is just minor injury and nothing is related to old one.

My current efficiency drops so fast!

Maybe towards the end of the semester, I become stupid. Or I look too much NBA and related news. My instinct is gone very quickly. Even one set network homework takes me almost the whole sunday. And I still haven't finished it. I am looking foward winter break now and need to control online time.

Future is Present

This is one of the beautiful thing you can learn from math course. In financial calculus class, the first half class is devoted to binomial tree model. In that model, you rebalance your portfolio in the near future (Delta t_i) based on the information you know during Delta t. But in continuous model, Delta t becomes delta, future collapses to present. You need to do rebalance all the time. If not, you will be arbitraged by others.

If you don't want others to arbitrage you, you'd better to know future is present and try you best continuously.