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 Educación 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 Innovación TIN2009-1371

Diagnosing Errors in DbC Programs Using Constraint Programming

Model-Based Diagnosis allows to determine why a correctly designed system does not work as it was expected. In this paper, we propose a methodology for software diagnosis which is based on the combination of Design by Contract, Model-Based Diagnosis and Constraint Programming. The contracts are specified by assertions embedded in the source code. These assertions and an abstraction of the source code are transformed into constraints, in order to obtain the model of the system. Afterwards, a goal function is created for detecting which assertions or source code statements are incorrect. The application of this methodology is automatic and is based on Constraint Programming techniques. The originality of this work stems from the transformation of contracts and source code into constraints, in order to determine which assertions and source code statements are not consistent with the specification.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

Constraint satisfaction techniques for diagnosing errors in Design by Contract software

Design by Contract enables the development of more reliable and robust software applications. In this paper, a methodology that diagnoses errors in software is proposed. This is based on the combination of Design by Contract, Modelbased Diagnosis and Constraint Programming. Contracts are specified by using assertions. These assertions together with an abstraction of the source code are transformed into constraints. The methodology detects if the contracts are consistent, and if there are incompatibilities between contracts and source code. The process is automatic and is based on constraint programming.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

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®. 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 Educación y Ciencia DIP2006-15476-C02-0

Automating correctness verification of artifact-centric business process models

Context: The artifact-centric methodology has emerged as a new paradigm to support business process management over the last few years. This way, business processes are described from the point of view of the artifacts that are manipulated during the process. Objective: One of the research challenges in this area is the verification of the correctness of this kind of business process models where the model is formed of various artifacts that interact among them. Method: In this paper, we propose a fully automated approach for verifying correctness of artifact-centric business process models, taking into account that the state (lifecycle) and the values of each artifact (numerical data described by pre and postconditions) influence in the values and the state of the others. The lifecycles of the artifacts and the numerical data managed are modeled by using the Constraint Programming paradigm, an Artificial Intelligence technique. Results: Two correctness notions for artifact-centric business process models are distinguished (reachability and weak termination), and novel verification algorithms are developed to check them. The algorithms are complete: neither false positives nor false negatives are generated. Moreover, the algorithms offer precise diagnosis of the detected errors, indicating the execution causing the error where the lifecycle gets stuck. Conclusion: To the best of our knowledge, this paper presents the first verification approach for artifact-centric business process models that integrates pre and postconditions, which define the behavior of the services, and numerical data verification when the model is formed of more than one artifact. The approach can detect errors not detectable with other approaches.Ministerio de Educación y Ciencia TIN2009-1371

Contract-based Diagnosis for Business Process Instances using Business Compliance Rules

In order to increase the quality of business pro cesses when they are automated, the correctness of the activities can be checked by means of an analysis of the corresponding business compli ance rules. By analyzing the trace of an instance of a business process, it is possible to detect the correctness of the process and to determine which activity is faulty. Each activity or set of activities is related to a set of business compliance rules, which work as contracts that the activities must satisfy throughout the dataflow. In order to diagnose a business process instance, not all the activities participate in every single execution, since there are control flows that per mit the execution of several branches for a varied number of times. We propose to automate the di agnosis of these executions of a business process taking into account the involved activities and their business compliance rules. Our main contri butions are related to the construction of the cor responding framework using several techniques related to the constraint programming paradigm to obtain the incorrect activities. The two differ ent proposals consider the tradeoff between the obtaining of the minimal diagnosis and the per formanceJunta de Andalucía P08-TIC-04095Ministerio de Ciencia y Tecnología TIN2009-1371

Using Distributed CSPs to Model Business Processes Agreement in Software Multiprocess

A business process consists of a set of activities which are performed in a coordination way to obtain an objective. Sometimes the definition of this objective using only a classic business processes management is not possible. When the choreography of the processes cannot be defined with a combination of tasks using sequences, conditions, ’xor’, ’or’ and ’split’ control flow patterns, another representation and solution are necessary to be used. This problem makes difficult the decision making in software management projects. In this paper a way to describe a process agreement is described where the execution and the number of tasks execution order of the Web Services cannot be defined. As a case study, the resource distribution in a multiproject development environment is used. In this case, the processes have to achieve an agreement in function of the business rules that relate the processes. In order to achieve this objective, the Distributed Constraint Satisfaction Problems are used to model and solve this type of problemsJunta de Andalucía P08-TIC-04095Ministerio de Ciencia y Tecnología TIN2009-1371

Constraint-Driven Approach to Support Input Data Decision-Making in Business Process Management Systems

A business process consists of a set of activities that are performed in coordination in an organizational and technical environment (Weske 2007). The base of business process management systems (BPMS) is the explicit representation of business processes with their activities and the execution constraints between them. Compliance rules represent a natural step to include requirements between business functionality and data. For the design of a whole business process management (van der Aalst et al. 2003), it is necessary to design the model of activities and define the causal and temporal relationships between them (Walzer et al. 2008). Compliance rules can help to complete this information, since they can be used to validate business data (Chesani et al. 2008).Junta de Andalucía P08-TIC-04095Ministerio de Ciencia y Tecnología TIN2009-1371

Computing alignments with constraint programming : the acyclic case

Conformance checking confronts process models with real process executions to detect and measure deviations between modelled and observed behaviour. The core technique for conformance checking is the computation of an alignment. Current approaches for alignment computation rely on a shortest-path technique over the product of the state-space of a model and the observed trace, thus suffering from the well-known state explosion problem. This paper presents a fresh alternative for alignment computation of acyclic process models, that encodes the alignment problem as a Constraint Satisfaction Problem. Since modern solvers for this framework are capable of dealing with large instances, this contribution has a clear potential. Remarkably, our prototype implementation can handle instances that represent a real challenge for current techniques. Main advantages of using Constraint Programming paradigm lie in the possibility to adapt parameters such as the maximum search time, or the maximum misalignment allowed. Moreover, using search and propagation algorithms incorporated in Constraint Programming Solvers permits to find solutions for problems unsolvable with other techniques.Ministerio de Economía y Competitividad TIN2015-63502-C3-2-RMinisterio de Economía y Competitividad TIN2013-46181-C2-1-