- A new problem and its solution is appended to basestockEx.pdf at 20:32 on May 3.

- Formula sheet for OPRE 6302 exams: Formula sheet.

- 2011 Spring quiz average=67%; max=88%; min=48%; StDev=10%.

- Updated on March 28: See some sample quiz questions including solutions to essay questions of Spring 2011 Quiz.

- Welcome to PortOM. Please read these announcements first whenever you have a question. If your question is not answered, e-mail me.

- See some sample final questions.

- See a finance prof's take on models.

- Midterm course evaluations/suggestions: Please fill out an evaluation form and put into my office. These evaluations are just for me to improve the course before it ends.

- Case grading will be more flexible than homework grading. In the case reports, your approach is as important as your result. So you will get plenty of marks even if you do not get exact answers. My policy is actually to make sure that no report receives less than 60%. A decent report easily gets at least 80%. Knowing this, do not worry much about getting some numbers that will exactly match mine.

- Question of week 7: How does the utilization of a queue server change when the variability (measured by standard deviation) of the service times go up?

- Question of week 6: Suppose f(x_1,x_2) is a nonlinear function of (x_1,x_2), is it ever possible that the inequality f(x_1,x_2) >= 1 can be converted into equivalent linear inequalities/equalities?

- Question of week 5: If we sum up to linear functions, is the sum still linear?

- Question of week 4: What is the derivative of C(Q)=2Q^2+3/Q?

- Question of week 3: If X has a normal distribution with mean 4 and variance 2, what is the distribution of (3X)?

- Question of week 2: If X has a normal distribution with mean 4 and variance 2, what is the distribution of (X+10)?

- Question of week 1: What is the variance of a sample made of two observations 4 and 6 if the sample is coming from a distribution whose mean is 5?

- Spring 2006 curve: A for more than (Average + StDev/2); C for less than (Average - 1.5 StDev); B for the remaining. 12 As, 15 Bs and 4Cs are given. Average and StDev are for the overall grade were 84.7 and 4.5. Note that Average increases and StDev decreases in the overall grades due to higher and less variable hw and case grades.

- 2007 Spring quiz: Average=67% and StDev=11.25%.

- 2006 Spring quiz: Average=78% and StDev=9.75%.

- If you wonder about skipping the formulation stage and writing the data into a spreadsheet. This shortcut may be ok for a small problem after you build enough experience with formulations. Otherwise, it is prone to errors. Moreover, in real life problems, the data are pulled from databases by using queries. They are not put into tables (unless you want to see a spreadheet with billion cells). Instead, the formulations and the data are used to build a "matrix" representing the constraints. That is, the data and the formulation file are joined to create a matrix in the computer memory. This join operation is somewhat similar to "join" in database theory. To understand more of this see an AMPL formulation file at www.ampl.com/EXAMPLES/MCDONALDS/diet1.mod and the associated data file in www.ampl.com/EXAMPLES/MCDONALDS/diet1.dat. Note that the same formulation file can be "joined" with different data files to obtain different instances of the same problem. You can download AMPL's student version at www.ampl.com/DOWNLOADS/index.html.

- If you are interested in the solution algorithm, "called Simplex", for LP formulations, I suggest that you go back to my teaching page, click on OPRE6201, use the password "ilikeor". This will take you to another course where Simplex is discussed with a numerical example. To get a sense of Simplex, please read Chapter 2 of course notes of OPRE 6201. If you want to hear a discussion on this, e-mail me. If there are more than 8 students interested in Simplex, I shall teach it during office hours in a classroom.

- The best way to learn about formulations is to do exercises: Some solved formulation exercises: 11 in LP slides, 7 in the document called "moreLPproblems", 9 in "some sample questions" below, more in the posted/solved exams of OPRE 6201 course (accessible with password ilikeor). These give you approximately 35 solved exercises.

- There are also unsolved problems at the end of the formulation notes. Coupled with the solved exercises mentioned above, if you just look at the notes I make available, you will be exposed to about 50-55 formulation exercises only for linear programming. You will also see integer programming formulations, which will bring the number of formulations you see to about 55-60. Unless these are enough, more solved and unsolved exercises can be found in operations management textbooks available in the library.

- Quizes are cumulative. The AACSB organization which accredits the SOM is enforcing some rules to improve student learning. Two of these rules are: i) Standardizing the content of the course over all OPRE 6302 sections. ii) Encouraging cumulative exams.

- Course materials can be updated during the course so do not print all of them. I reserve the right to modify course notes before I discuss them. Any modification after the discussion will be announced here.

- Your minimum hw grade will be dropped.

- When solving a case, think of yourself as a consultant who faces the problem definition. You are to show to the company employing you that you understand the problem. Impress them with some quick computations. Then make some suggestions. If you just repeat to the company people what they already know they would not hire you anymore.

- Your grades will be posted on eLearning under OPRE 6302. Go to www.utdallas.edu to access eLearning.

- You may want to join APICS, a US wide organization of operation management professionalls. I am told that student membership is $20/year and student members receive discounts from APICS certification tests. For more info e-mail: apicsutd@yahoo.com .

- Need counseling on effective Test Taking and Time Management, see Dr. Jennifer Hartman of UTD Student counseling center. For more info call 972.883.2575 or e-mail jhartman@utdallas.edu.

- Late hw submissions delay the process of grading and posting. Please do not submit late unless you get permission to do so. Unauthorized late submissions will be subject to grade adjustments.

- For supply chain issues/questions/discussion/job announcements, join Yahoo's Supply Chain Management Group.

- Since I have many students, I cannot possibly send personal e-mails to tell grades.

- What is the difference between notations A:=B and A=:B? You may see these rarely in the notes. A:=B means A is defined to be equal to B. A=:B means B is defined to be equal to A. In both cases, A=B. But := and =: tell us whether B existed first or A existed first. This is a kind of a chicken and egg issue. However the notation can be helpful in exposition.