midterm 1 specific practice

Question 1

Name the five elements of a descision model

Answer 1

decision variables, parameters, constraints, outputs, objective functions

Question 2

Describe decision variables

Answer 2

represents quantities that can control or change(things the solver finds and fills in yellow cells)

Question 3

Describe parameters

Answer 3

inputs that influence decision making but cannot control (blue colored cells, values given to us)

Question 4

Describe outputs

Answer 4

results that model predicts based on decision variables and parameters( i think all outputs the solver fills in)

Question 5

Describe objective function

Answer 5

outputs that represent measures of performance (the green revenue cell)

Question 6

Describe contraints

Answer 6

interaction of inputs that limit feasibility of decisions (the blue cells that have conditional operators with other blue cells typically)

Question 7

Optimization: describe optimization given a set of parameters

Answer 7

finding the best feasible combination of values for the decision variables

Question 8

Describe a feasible combination of values for the decision variables

Answer 8

one that meets all the constraints of the model

Question 9

The objective function determines what is best in terms of either ____ or ___ it’s value

Answer 9

maximizing or minimizing

Question 10

Not all mathematical models are optimization models, true or false?

Answer 10

true, some just descrbie logical relationship between inputs and outputs

Question 11

list the color of cells for Parameter, Decision Variable, Objective function (output), Calculation

Answer 11

blue, yellow, green, white

Question 12

What are the three key questions to ask first?
What are the ___ to be made?
What are the ___ on these descisions?
What is the overall _____ for these decisions?

Answer 12

decisions, constraints, measure of performance?

Question 13

Example Maximization and Feasibility: Regarding the diagram of feasibility range, what points would be the optimal solutions?

Answer 13

the corner points

Question 14

Regarding graph and Feasibility: What does it mean to have redundant constriants?

Answer 14

a feasibility line or constraint that is outside feasibility already, but could become relevant later

Question 15

Name the four Special conditions in LP Models

Answer 15

multiple optimal solutions, redundant constraints, unboundedness, infeasibility

Question 16

Describe multiple optimal solutions

Answer 16

graph, when there is a line segment same as objective function instead of point so it has multiple optimal solutions

Question 17

Describe redundant constraints

Answer 17

a feasibility line that doesnt effect current feasibility

Question 18

Describe unboundedness

Answer 18

no limits, goes to infinite

Question 19

Describe infeasibility

Answer 19

constraints to not define any feasible region, check sign of operation

Question 20

List the types of models: Allocation Model, Covering, Blending, Transportation and assignment, transshipment, multiperiod and inventory models, netwrok models with yield, cash flow problem,

Answer 20

Allocation Model, Covering, Blending, Transportation and assignment, transshipment, multiperiod and inventory models, netwrok models with yield, cash flow problem,

Question 21

List the types of models

Answer 21

Allocation Model, Covering, Blending, Transportation and assignment, transshipment, multiperiod and inventory models, netwrok models with yield, cash flow problem,

Question 22

Describe Allocation Model

Answer 22

Maximizing and objective, with less than constraints on capacity

Question 23

Describe Covering problems

Answer 23

minimizing, subject to greater than or equal constrains on coverage

Question 24

Describe Blending problems

Answer 24

nonlinear, convert to linear constraints

Question 25

Transportation and assignment models: Describe network models

Answer 25

linear programs with special structure, describes configurations of flow in a connected system (nodes and arcs)

Question 26

Describe transshipment model

Answer 26

Multiple stages of flow (multiple nodes) instead of just one

Question 27

Describe multiperiod and inventory models

Answer 27

flow and network but with multiple periods, with conservation of flow