Pedro Gómez-Gasquet

An agent-based genetic algorithm for hybrid flowshops with sequence dependent setup times to minimise makespan

This paper deals with a variant of flowshop scheduling, namely, the hybrid or flexible flowshop with sequence dependent setup times. This type of flowshop is frequently used in the batch production industry and helps reduce the gap between research and operational use. This scheduling problem is NP-hard and solutions for large problems are based on non-exact methods. An improved genetic algorithm (GA) based on software agent design to minimise the makespan is presented. The paper proposes using an inherent characteristic of software agents to create a new perspective in GA design. To verify the developed metaheuristic, computational experiments are conducted on a well-known benchmark problem dataset. The experimental results show that the proposed metaheuristic outperforms some of the well-known methods and the state-of-art algorithms on the same benchmark problem dataset.

A collaborative scheduling GA for products-packages service within extended selling chains environment

The theory of network coordination provides theoretical foundations to explain how companies can overcome organizational boundaries and constraints to jointly manage business processes across their selling chains. In particular, this work focuses on Collaborative Scheduling, a collaboration process whereby selling chain trading partners activate either on-line or off-line inter-firm coordination mechanisms to jointly plan production activities in order to deliver the final products to end customers each one of them, being the delivery date as close to the date desired as possible. The problem of collaborative scheduling is formally defined by means of a mathematical model. In the model, the defined objective function has the goal to minimize the total weighted tardiness of the package of products acquired by the clients to be delivered in a specific date. The delivery date of each Product-Package is conditioned by the latest date established by each supplier for each product that forms part of the same one. Besides, having different process times for each product and different penalties for each Product-Package, each supplier can offer a different mix of additional products with different due date. Due to the complexity of the problem a Genetic Algorithm has been the approach taken for its resolution. The GA elements and procedures are defined and the parameters are tuned. Although the major contribution of this work focuses on the algorithmic development of a proposal in the context of operations research that could help to solve the problem also is discussed the environment in which this occurs and that justifies our interest. In order to validate the proposed solutions diverse configurations are presented and the results obtained by means of the GA and some heuristics rules are compared.

Towards a Modeling Framework for Service-Oriented Digital Ecosystems

Reference modeling for collaborative networks has been identified as a key topic in consolidating this new scientific discipline. Earlier contributions on this field have provided a solid initial framework and they are considered starting points for this work. Based on two well-known approaches, the CIMOSA and ARCON modeling frameworks, what this work proposes is a set of modeling constructs for CNO modeling under a service-orientation perspective. Service Entities are incorporated as a third approach that may be considered if service ecosystems are being modeled.

Service-Oriented Approach Supporting Dynamic Manufacturing Networks Operations

In the current economic crisis, also the manufacturing sector is asked to evolve towards more dynamic organizational structures within which, composing manufacturing processes, almost in real time, will become a need. This work aims at introducing flexibility and dynamisms to current manufacturing processes by separating its tasks from its final performers. With the proposed approach, the performers’ replacement can be done almost seamlessly. Additionally, the approach shows how dynamic negotiation and contracting, either for a whole process or a single activity, can be smoother if the task specification is based on a standard service interface defined at the ecosystem level. At the end, a prototype implementation is briefly described.In the current economic crisis, also the manufacturing sector is asked to evolve towards more dynamic organizational structures within which, composing manufacturing processes, almost in real time, will become a need. This work aims at introducing flexibility and dynamisms to current manufacturing processes by separating its tasks from its final performers. With the proposed approach, the performers’ replacement can be done almost seamlessly. Additionally, the approach shows how dynamic negotiation and contracting, either for a whole process or a single activity, can be smoother if the task specification is based on a standard service interface defined at the ecosystem level. At the end, a prototype implementation is briefly described.

Open Ecosystems, Collaborative Networks and Service Entities Integrated Modeling Approach

This paper introduces an integrated modeling approach that has been used to design and implement the ColNet platform. ColNet is the result of creating an integrated system, supporting distributed business processes design and execution in a Collaborative Network (CN) belonging to an Open Ecosystem (VBE). The work has been carried out as a part of the FP7 REMPLANET European Project, which aims at providing methods and tools for better decision-making in non-hierarchical collaborative networks. The functional alignment of Open Service Ecosystems, Collaborative Networks and Services Entities lifecycles is adopted as main functional requirements for the platform design and implementation while, at the same time, they raise an integrated modeling need. Both constitute the underlying approach followed when designing and implementing ColNet and are briefly described here.

Integrated Approach for Interoperability in Collaborative Networks and Service-based Ecosystems

Companies are increasingly spending their budget in IT solutions supporting their current operations. Efficiency of their internal business processes is almost achieved with ERP systems or Business Process Management systems. However, when they need to interoperate at collaborative networks (CN) level, by contributing to extended business processes, most of times point-to-point solutions connecting two companies are designed and implemented. Digital business ecosystems are emerging as enablers of future CNs where interoperability barriers are expected to be lower due to the fact of being based on commonly agreed reference models that will rule the network design and operation. In addresing this issue, this paper introduces an integrated framework for the integrated modelling of digital ecosystems, collaborative networks, and service entities. Last section briefly describes an IT platform which is being implemented by applying it.

A makespan minimization in an m-stage flow shop lot streaming with sequence dependent setup times: MILP model and experimental approach.

This paper considers the recent growing interest the scientific community has put over the use of Lot Streaming technics (LS) or lot splitting. Implications are highlighted, from the scheduling point of view. It is presented this consideration and a MILP mathematical model to minimize makespan in an n-job flow shop problem with sequence dependent setup times (SDST). At the same time, the model is resolved, for the two- and three-machine flow shop, with the purpose of analyzing, through a design of experiments, which is the achieved makespan reduction and computation time increment regarding to no LS consideration used. Finally, it will be reflected about the use of non-optimum technics relating makespan values and expected calculation time.

Formative Assessment for the Analysis and Problem Solving Transversal Competence in Master Degree

The Universitat Politecnica de Valencia has introduced thirteen transversal competences in the curricula of undergraduate and graduate degrees. One of the transversal competences is “Analysis and Problem Solving”. This competence had been assessed non-uniformly in the Master Degree in Advanced Engineering Production, Logistics and Supply Chain due to the fact that the assessment lacked a comprehensive and accessible tool to the students that exposed the indicators and levels of achievement of the competence. In addition, it was important to design a tool where all the instructors agreed on the main features so that the tool could be used in both semesters by instructors aiding to support the formative assessment of the competence. This paper presents a methodology and the design of a tool to perform formative assessment of analysis and problem solving competence. It had been implemented in three courses (three pilot applications) and five learning activities to support the formative assessment as well as to update the tool with the feedback collected by each pilot application. The analysis of the pilot applications show the positive results obtained and the recommendation of students for its implementation.

Service Entities in Manufacturing Networks

Service Entities have been proposed as a relevant approach that may help to support structural and functional Collaborative Networks modeling and deployment, especially when they are engineered inside Virtual Breeding Environments. This work is intended to explore the suitability of such approach to next-generation manufacturing networks. By means of a supporting case, the paper identifies main service entities of the problem domain, exemplifies how service interfaces can be defined and how can they be used to compose abstract collaborative processes definitions.

The Design of an Agent-Based Production Scheduling Software Framework for Improving Planning-Scheduling Collaboration

In the operation management environment, the process of production scheduling is responsible for detailing operating activities by indicating a set of methods and tools that are conditioned, among other restrictions, by the tactical decisions that are made in the production planning environment. Although, theoretically, a bi-directional flow of information should exist among both environments of decisions that permit those who are involved to coordinate both levels in practice, such does not occur because of a structured decision-making tool gap. This document proposes an architecture that is based on agents software designed with INGENIAS methodology and proposed from an analysis of requirements that is based on CIMOSA. Once it is implemented, a prototype that employs JADE has been carried out to test and verify its suitable operation.