Solving a Sequencing Problem: Allocating Cost Savings

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SUMMARY

This discussion focuses on a sequencing problem involving three players and six jobs, specifically analyzing the allocation of cost savings based on processing times. The processing times are defined as follows: pA = 8, pB = 10, pC = 15, pD = 5, pE = 6, and pF = 12. The optimal job order identified is (EFD), leading to a new sequence of (EFDCBA). The calculated values of gij are provided, with gAB = 16 and gAE = 32 among others. The discussion also raises questions about the correctness of the EGS value, specifically EGS1 = 102.

PREREQUISITES
  • Understanding of sequencing problems in operations research
  • Familiarity with processing time calculations and job scheduling
  • Knowledge of cost allocation methods in optimization
  • Proficiency in LaTeX for mathematical notation
NEXT STEPS
  • Research the principles of job scheduling algorithms in operations research
  • Explore cost allocation techniques in optimization problems
  • Learn about the EGS (Expected Gain from Scheduling) method and its applications
  • Study LaTeX formatting for clearer mathematical presentations
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Operations researchers, optimization analysts, and students studying scheduling algorithms will benefit from this discussion, particularly those interested in cost allocation strategies within sequencing problems.

Cyn
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<Moderator's note: LaTeX code edited.>

1. Homework Statement

Hi, I have a question.
I have a sequencing problem ##(N, \sigma_{0}##, ##\{p_{j}\}_{j\in J}, \{c_{i}\}_{i\in N})## with ##N = \{1,2,3\}## the set of players, and ##J = \{A,B,C,D,E,F\}## the set of jobs. The processing times of the jobs are:
$$p_{A} =8\\
p_{B} =10 \\
p_{C} = 15\\
p_{D} = 5 \\
p_{E}=6\\
p_{F}= 12$$
De set jobs van de spelers, ##J(i)##, zijn:
$$J(1) = \{B,E\}, J(2) = \{A,D\}, J(3) =\{C,F\},$$
##c_{1}(\sigma) = 7min\{C_{B}(\sigma),C_{E}(\sigma)\}##,
##c_{2}(\sigma) = 4min\{C_{A}(\sigma),C_{D}(\sigma)\}##,
##c_{3}(\sigma) = 12min\{C_{C}(\sigma),C_{F} (\sigma)\}##,
##\sigma_{0} = (A B C D E F).##

Homework Equations


What is the allocation of the cost savings?

The Attempt at a Solution


I have calculated the $\alpha$'s and the optimal order begins with (EFD). Now I want to calculate an allocation of the cost savings.
I have said that my new order becomes ##(EFDCBA)##. So ##MP(\sigma_{0})=\{(A,B), (A,C), (A,D), (A,E), (A,F), (B,C), (B,D), (B,E), (B,F), (C,D), (C,E), (C,F), (D, E), (D,F)\}##
Then, I have calcultated ##g_{ij}. (g_{ij} = \alpha_{j}p_{i}-\alpha_{i}p_{j}).##

##g_{AB} = 16;
g_{AE} = 32;
g_{BC} = 15;
g_{BD} = 5;
g_{BE} = 28;
g_{BF} = 36;
g_{CE} = 33;
g_{DE} = 11##
If we use EGS, is it correct that ##EGS_{1}= 102##?​
 
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Cyn said:

Homework Statement


Hi, I have a question.
I have a sequencing problem (N, $\sigma_{0}$, $\{p_{j}\}_{j\in J}, \{c_{i}\}_{i\in N}$) with N = \{1,2,3\} the set of players, and J = \{A,B,C,D,E,F\} the set of jobs. The processing times of the jobs are:
$$p_{A} =8\\
p_{B} =10 \\
p_{C} = 15\\
p_{D} = 5 \\
p_{E}=6\\
p_{F}= 12$$
De set jobs van de spelers, $J(i)$, zijn:
$$J(1) = \{B,E\}, J(2) = \{A,D\}, J(3) =\{C,F\},$$
$c_{1}(\sigma) = 7min\{C_{B}(\sigma),C_{E}(\sigma)\}$,
$c_{2}(\sigma) = 4min\{C_{A}(\sigma),C_{D}(\sigma)\}$,
$c_{3}(\sigma) = 12min\{C_{C}(\sigma),C_{F} (\sigma)\}$,
$\sigma_{0}$ = (A B C D E F).

Homework Equations


What is the allocation of the cost savings?

The Attempt at a Solution


I have calculated the $\alpha$'s and the optimal order begins with (EFD). Now I want to calculate an allocation of the cost savings.
I have said that my new order becomes (EFDCBA). So MP($\sigma_{0}$)={(A,B), (A,C), (A,D), (A,E), (A,F), (B,C), (B,D), (B,E), (B,F), (C,D), (C,E), (C,F), (D, E), (D,F)}
Then, I have calcultated $g_{ij}$. ($g_{ij} = \alpha_{j}p_{i}-\alpha_{i}p_{j}$).

$g_{AB} = 16;
g_{AE} = 32;
g_{BC} = 15;
g_{BD} = 5;
g_{BE} = 28;
g_{BF} = 36;
g_{CE} = 33;
g_{DE} = 11$
If we use EGS, is it correct that $EGS_{1}= 102?​
Your problem statement is very difficult to understand.
1) One thing that would help a lot would be to use "##" instead of "$" to delimit your LaTeX notation. Then it would display correctly.
2) Please give definitions of the variables. What do p, c, g, σ and α represent?
3) You give as your goal that you want to allocate cost savings, but you have not clearly defined your objective in mathematical terms. Cost savings relative to what? What are you optimizing?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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