1,901 research outputs found
Scheduling with controllable processing times in a CNC environment
Cataloged from PDF version of article.Flexible manufacturing systems give a manufacturer some capabilities to consider
and solve different manufacturing problems simultaneously instead of one
by one in a sequential manner. Using those makes her more competitive in the
market. One of those capabilities is controllable processing times. By using this
capability, the due date requirements of customers can be satisfied much more effectively.
Processing times of the jobs in a CNC machine can be easily controlled
via machining conditions such that they can be increased or decreased at the expense
of tooling cost. In this study, we consider the problem of scheduling a set
of jobs by minimizing the sum of total weighted tardiness, tooling and machining
costs on a single CNC machine. This problem is NP-hard since the total weighted
tardiness problem is NP-hard alone. Moreover, the problem is non-linear because
of the nature of the tooling cost. We proposed a DP-based heuristic to solve the
problem for a given sequence and designed a local search algorithm that uses it
as a base heuristic.İlhan, TaylanM.S
Single machine scheduling problems with uncertain parameters and the OWA criterion
In this paper a class of single machine scheduling problems is discussed. It
is assumed that job parameters, such as processing times, due dates, or weights
are uncertain and their values are specified in the form of a discrete scenario
set. The Ordered Weighted Averaging (OWA) aggregation operator is used to
choose an optimal schedule. The OWA operator generalizes traditional criteria
in decision making under uncertainty, such as the maximum, average, median or
Hurwicz criterion. It also allows us to extend the robust approach to
scheduling by taking into account various attitudes of decision makers towards
the risk. In this paper a general framework for solving single machine
scheduling problems with the OWA criterion is proposed and some positive and
negative computational results for two basic single machine scheduling problems
are provided
Parameterized complexity of machine scheduling: 15 open problems
Machine scheduling problems are a long-time key domain of algorithms and
complexity research. A novel approach to machine scheduling problems are
fixed-parameter algorithms. To stimulate this thriving research direction, we
propose 15 open questions in this area whose resolution we expect to lead to
the discovery of new approaches and techniques both in scheduling and
parameterized complexity theory.Comment: Version accepted to Computers & Operations Researc
How the structure of precedence constraints may change the complexity class of scheduling problems
This survey aims at demonstrating that the structure of precedence
constraints plays a tremendous role on the complexity of scheduling problems.
Indeed many problems can be NP-hard when considering general precedence
constraints, while they become polynomially solvable for particular precedence
constraints. We also show that there still are many very exciting challenges in
this research area
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