44 research outputs found
Planning and Scheduling of Business Processes in Run-Time: A Repair Planning Example
Over the last decade, the efficient and flexible management of business
processes has become one of the most critical success aspects. Furthermore, there
exists a growing interest in the application of Artificial Intelligence Planning and
Scheduling techniques to automate the production and execution of models of organization.
However, from our point of view, several connections between both
disciplines remains to be exploited. The current work presents a proposal for modelling
and enacting business processes that involve the selection and order of the
activities to be executed (planning), besides the resource allocation (scheduling),
considering the optimization of several functions and the reach of some objectives.
The main novelty is that all decisions (even the activities selection) are taken in
run-time considering the actual parameters of the execution, so the business process
is managed in an efficient and flexible way. As an example, a complex and representative
problem, the repair planning problem, is managed through the proposed
approach.Ministerio de Ciencia e Innovaci贸n TIN2009-13714Junta de Andaluc铆a P08-TIC-0409
A CSP model for simple non-reversible and parallel repair plans
Thiswork presents a constraint satisfaction problem
(CSP) model for the planning and scheduling of disassembly
and assembly tasks when repairing or substituting
faulty parts. The problem involves not only the ordering of
assembly and disassembly tasks, but also the selection of
them from a set of alternatives. The goal of the plan is the minimization
of the total repairing time, and the model considers,
apart from the durations and resources used for the assembly
and disassembly tasks, the necessary delays due to the change
of configuration in the machines, and to the transportation
of intermediate subassemblies between different machines.
The problem considers that sub-assemblies that do not contain
the faulty part are nor further disassembled, but allows
non-reversible and parallel repair plans. The set of all feasible
repair plans are represented by an extended And/Or graph.
This extended representation embodies all of the constraints
of the problem, such as temporal and resource constraints and
those related to the selection of tasks for obtaining a correct
plan.Ministerio de Educaci贸n y Ciencia DIP2006-15476-C02-0
Supporting the Optimized Execution of Business Processes through Recommendations
In order to be able to flexibly adjust a company鈥檚 business
processes (BPs) there is an increasing interest in flexible Process-Aware
Information Systems (PAISs). This increasing flexibility, however, typically
implies decreased user guidance by the PAIS and thus poses additional
challenges to its users. This work proposes a recommendation
system which assists users during process execution to optimize performance
goals of the processes. The recommendation system is based on a
constraint-based approach for planning and scheduling the BP activities
and considers both the control-flow and the resource perspective.Ministerio de Ciencia e Innovaci贸n TIN2009-1371
A Constraint-based Model for Multi-objective Repair Planning
This work presents a constraint based model for the
planning and scheduling of disconnection and connection
tasks when repairing faulty components in a system.
Since multi-mode operations are considered, the
problem involves the ordering and the selection of the
tasks and modes from a set of alternatives, using the
shared resources efficiently. Additionally, delays due to
change of configurations and transportation are considered.
The goal is the minimization of two objective functions:
makespan and cost. The set of all feasible plans
are represented by an extended And/Or graph, that embodies
all of the constraints of the problem, allowing non
reversible and parallel plans. A simple branch-and-bound
algorithm has been used for testing the model with different
combinations of the functions to minimize using the
weighted-sum approach.Ministerio de Educaci贸n y Ciencia DIP2006-15476-C02-0
Conformance checking and diagnosis for declarative business process models in data-aware scenarios
A business process (BP) consists of a set of activities which are performed in coordination in an organizational
and technical environment and which jointly realize a business goal. In such context, BP management
(BPM) can be seen as supporting BPs using methods, techniques, and software in order to design,
enact, control, and analyze operational processes involving humans, organizations, applications, and
other sources of information. Since the accurate management of BPs is receiving increasing attention,
conformance checking, i.e., verifying whether the observed behavior matches a modelled behavior, is
becoming more and more critical. Moreover, declarative languages are more frequently used to provide
an increased flexibility. However, whereas there exist solid conformance checking techniques for imperative
models, little work has been conducted for declarative models. Furthermore, only control-flow perspective
is usually considered although other perspectives (e.g., data) are crucial. In addition, most
approaches exclusively check the conformance without providing any related diagnostics. To enhance
the accurate management of flexible BPs, this work presents a constraint-based approach for conformance
checking over declarative BP models (including both control-flow and data perspectives). In addition,
two constraint-based proposals for providing related diagnosis are detailed. To demonstrate both
the effectiveness and the efficiency of the proposed approaches, the analysis of different performance
measures related to a wide diversified set of test models of varying complexity has been performed.Ministerio de Ciencia e Innovaci贸n TIN2009-1371
OptBPPlanner: Automatic Generation of Optimized Business Process Enactment Plans
Unlike imperative models, the specifi cation of business process (BP)
properties in a declarative way allows the user to specify what has to be done instead
of having to specify how it has to be done, thereby facilitating the human work
involved, avoiding failures, and obtaining a better optimization. Frequently, there
are several enactment plans related to a specifi c declarative model, each one
presenting specifi c values for different objective functions, e.g., overall completion
time. As a major contribution of this work, we propose a method for the automatic
generation of optimized BP enactment plans from declarative specifi cations. The
proposed method is based on a constraint-based approach for planning and scheduling
the BP activities. These optimized plans can then be used for different purposes
like simulation, time prediction, recommendations, and generation of optimized BP
models. Moreover, a tool-supported method, called OptBPPlanner, has been implemented
to demonstrate the feasibility of our approach. Furthermore, the proposed
method is validated through a range of test models of varying complexity.Ministerio de Ciencia e Innovaci贸n TIN2009-1371
Improving the Computational Efficiency in Symmetrical Numeric Constraint Satisfaction Problems
Models are used in science and engineering for experimentation,
analysis, diagnosis or design. In some cases, they can be considered
as numeric constraint satisfaction problems (NCSP). Many models
are symmetrical NCSP. The consideration of symmetries ensures that
NCSP-solver will find solutions if they exist on a smaller search space.
Our work proposes a strategy to perform it. We transform the symmetrical
NCSP into a newNCSP by means of addition of symmetry-breaking
constraints before the search begins. The specification of a library of possible
symmetries for numeric constraints allows an easy choice of these
new constraints. The summarized results of the studied cases show the
suitability of the symmetry-breaking constraints to improve the solving
process of certain types of symmetrical NCSP. Their possible speedup
facilitates the application of modelling and solving larger and more
realistic problems.Ministerio de Ciencia y Tecnolog铆a DIP2003-0666-02-
Optimized Time Management for Declarative Workflows
Declarative process models are increasingly used since they fit better
with the nature of flexible process-aware information systems and the requirements
of the stakeholders involved. When managing business processes, in addition,
support for representing time and reasoning about it becomes crucial. Given
a declarative process model, users may choose among different ways to execute
it, i.e., there exist numerous possible enactment plans, each one presenting specific
values for the given objective functions (e.g., overall completion time). This
paper suggests a method for generating optimized enactment plans (e.g., plans
minimizing overall completion time) from declarative process models with explicit
temporal constraints. The latter covers a number of well-known workflow
time patterns. The generated plans can be used for different purposes like providing
personal schedules to users, facilitating early detection of critical situations,
or predicting execution times for process activities. The proposed approach is
applied to a range of test models of varying complexity. Although the optimization
of process execution is a highly constrained problem, results indicate that
our approach produces a satisfactory number of suitable solutions, i.e., solutions
optimal in many cases
A Constraint-based Job-Shop Scheduling Model for Software Development Planning
This paper proposes a constraint-based model for the Job
Shop Scheduling Problem to be solved using local search techniques.
The model can be used to represent a multiple software process planning
problem when the different (activities of) projects compete for limited
sta庐. The main aspects of the model are: the use of integer variables
which represent the relative order of the operations to be scheduled, and
two global constraints, all different and increasing, for ensuring feasibility.
An interesting property of the model is that cycle detection in the sched-
ules is implicit in the satisfaction of the constraints. In order to test the
proposed model, a parameterized local search algorithm has been used,
with a neighborhood similar to the Nowicki and Smutnicki one, which
has been adapted in order to be suitable for the proposed model.Ministerio de Educaci贸n y Ciencia DIP2006-15476-C02-0