Priority rules-conventional priority rules, Mechanical Engineering

Priority Rules

A main concern rule is an algorithm that evaluates a priority number PNj for all operation j which enters the queue in front of a station (processing, cell, workplace, machine unit). This computation can be based on any of the subsequent quantities:

taj           :         arrival time in the queue;

oj           :         duration of the operation;

tdj           :         due date of the operation (static);

tdj*         :         due date of the corresponding job;

nj*         :         number of future operations in the job; and

wj*        :         remaining work content of the job.

Now, tdj is computed via backwards scheduling from the due date of the job along with constant flow factor.

Priority rules can be categorized into:

  • Static or Dynamic Rules, and
  • A Priori or a Posteriori Rules.

For a static priori rule, the value of PN is fixed when the job is initiating upto a linear shift consequent to the clock of increment of systems. Dynamic priority rules depend upon the  actual  evolution  of  the  system  and  cannot  be  calculated  beforehand  with no any simulation. An easy dynamic priority rule is FIFO: PNj = taj; an easy static priority rule is SPT: PNj = oj. But also the slack rule as:

PNj = tdj* - t - wj*,

 Here, t "absolute time", is static as per to our definition.

A priori priority rules compute PNj from the information that is available concerning the operation j alone. Absolutely not, a posteriori rules identify the situation that would arise if operation j would be scheduled like the next operation. They produce a comparison of damage that is done to the operations that have to wait additionally, while priority rules only compare the advantage acquired for operation j. Clearly, a posteriori rules cannot be static.

The subsequent rules have been proposed and all were reported to be successful in the literature as:

 

Posted Date: 3/5/2013 7:57:59 AM | Location : United States







Related Discussions:- Priority rules-conventional priority rules, Assignment Help, Ask Question on Priority rules-conventional priority rules, Get Answer, Expert's Help, Priority rules-conventional priority rules Discussions

Write discussion on Priority rules-conventional priority rules
Your posts are moderated
Related Questions
Brazing Brazing is a group of welding processes, which produces, coalescence of materials by heating them to a specific temperature and by using a filler metal having a liquids a

What is the sequence of this problem Job- 1 2 3 4 5 6 7 M/c M1 4 13 16 7 11 12 10 M2 9 11 11 7 13 2 4

physical meaning of viscous damping

Explain the Hydrostatic Pressure Hydrostatic Pressure also called Pressure because of Depth of a Fluid. It is required to define the pressure exerted by a static fluid column o

Gudgeon Pin: It forms the link between the small end of the connecting rod and the piston. It is a small pin as shown in Figure 2.13. Figure : Gudgeon Pin

Incompletely Constrained Motion: While a connection among the elements, building a pair is such that the constrained motion is not done by itself, but by some other means. Such a

equivalent evaporation of boiler..?


Dear Sir, I wish to know the equation for finding the resultant of the axial stress and bending stress for beams. Can you please help me. thanx in advance, Krishna.