Resource-constrained scheduling

Question 1

What are nonrenewable resources?

Answer 1

These are available on a total project basis, with a limited consumption availability for the entire project (money, energy, raw materials…)

Question 2

What are renewable resources?

Answer 2

These are available on a period-by-period basis, i.e. the available amount is renewed from period to period. Only the total resource use at every time instant is constrained. (manpower, machines, tools, space, …)

Question 3

When is a schedule feasible?

Answer 3

If the precedence and the renewable resource constraints are satisfied.

Question 4

What does RCPSP stands for?

Answer 4

Resource Constraint Project Scheduling Problem: Resolving the conflicts of resources by shifting activities forward in time

Question 5

How to schedule for maximizing the net present value?

Answer 5

Schedule the activities with a positive cash flow asap and the activities with a negative cash flow alap with respect to the precedence relations, resource constraints and the deadline.

Question 6

For what projects can maximizing NPV be relevant?

Answer 6

Big projects with high capitals and long durations.

Question 7

What is the lower bound of the duration of the critical chain?

Answer 7

The critical path

Question 8

What does RLPSP stands for?

Answer 8

Resource Leveling Project Scheduling Problem: Trying to schedule a precedence and resource feasible schedule within a predefined deadline with a resource use that is as level as possible within the project horizon.

Question 9

What does RCPSPDC stands for?

Answer 9

Resource Constrained Project Scheduling Problem Discounted Cash: Maximizing the NPV with respect to the precedence relations, resource use and deadline.

Question 10

What does RCPSPDC stands for?

Answer 10

Resource Constrained Project Scheduling Problem Discounted Cash: Maximizing the NPV with respect to the precedence relations, resource use and deadline.

Question 11

What is activity based priority rule?

Answer 11

Making a priority list based on characteristics of activities like duration.

Question 12

What is network based priority rule?

Answer 12

Making a priority list based on the network logic, i.e. set of activities and their precedence relations.

Question 13

What is critical path based priority rule?

Answer 13

Making a priority list using information from the critical path.

Question 14

What is resource based priority rule?

Answer 14

Making a priority list based on the network logic and the resource information.

Question 15

What does SSGS stands for?

Answer 15

Serial schedule generation scheme

Question 16

What does PSGS stands for?

Answer 16

Parallel schedule generation scheme

Question 17

What kinds of lower bounds are there?

Answer 17

1. Critical path lower bound
2. Resource based lower bound (sum of work content divided by total resources)
3. Critical sequence lower bound (combination 1 and 2)

Question 18

What types of cost are there?

Answer 18

Activity cost:
Fixed cost: Fixed amount independent of the duration and work content
Variable cost: cost per time unit dependent on the activity duration
Resource cost:
Cost per use: One time cost, independent
Cost per unit: Depends on quantity of resources
Fixed use: Quantity of resource is independent from duration
Variable use: Quantity varies with the duration

Question 19

What’s the different between a chain and a path?

Answer 19

A path is always a series of activities in a network defined by precedence relations.
A chain is not always a path, it can be linked by precedence relations but also by resource relations!

Question 20

The critical chain depends on:

Answer 20

1. Your own choices or quality used software
2. The available and used resources
3. The project objective

Question 21

What is the net present value?

Answer 21

Discounted value of money to the value it has today.

Question 22

What is a lump sum payment?

Answer 22

Big payment at the end of a project that is an incentive to determine the project as soon as possible if the net present value is the objective of the project. Otherwise the project will be postponed too much. Due to the lump sum payment, time becomes also important even if the objective is not time!

Question 23

Why is a lump sum payment needed?

Answer 23

To stimulate the contractor to finish the project in time as he will maximize the net present value.

Question 24

How to construct STP priority list?

Answer 24

Shortest Processing Time:

1. First make a list of the eligible activities
2. Select activity with shortest duration time
3. Update eligible list
4. Repeat
   NOTE: If duration is equal, choose lower ranking number

Question 25

Why do we need lower bounds for scheduling?

Answer 25

Scheduling gives a heuristic solution, we can validate the quality by measuring the percentage deviation from a lower bound