Chain recurrence and structure of ω-limit sets of multivalued semiflows (2020), Communications on pure and applied analysis 19 (4), pp. 2197–2217

Olexiy V. Kapustyan (Taras Shevchenko National University of Kyiv), Pavlo O. Kasyanov (Institute for Applied System Analysis National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute) and José Valero (Universidad Miguel Hernández de Elche)

Abstract: We study properties of ω-limit sets of multivalued semiflows like chain recurrence or the existence of cyclic chains. First, we prove that under certain conditions the ω-limit set of a trajectory is chain recurrent, applying this result to an evolution differential inclusion with upper semicontinous right-hand side. Second, we give conditions ensuring that the ω-limit set of a trajectory contains a cyclic chain. Using this result we are able to check that the ω-limit set of every trajectory of a reaction-diffusion equation without uniqueness of solutions is an equilibrium.


Defining a new graph inefficiency measure for the proportional directional distance function and introducing a new Malmquist productivity index (2020), European Journal of Operational Research 281, pp. 222-230

Jesus T. Pastor (University Miguel Hernandez of Elche), C. A. Knox Lovell (University of Queensland) and Juan Aparicio (University Miguel Hernandez of Elche)

Abstract: A natural multiplicative efficiency measure for the Constant Returns to Scale proportional directional distance function (pDDF) is derived, relating its associated linear program to that of the well-known output-oriented radial efficiency measurement model. Based on this relationship, a traditional CCD (Caves, Christensen and Diewert) Malmquist index is introduced to show that, when it is based on the new efficiency measure associated with the pDDF, rather than on a radial efficiency measure associated with an oriented distance function, it becomes a Total Factor Productivity (TFP) index. This constitutes a new result, because heretofore the traditional CCD Malmquist index has not been considered a TFP index. Additionally, a new decomposition of the CCD Malmquist index is proposed that expresses productivity change as the ratio of two components, productivity change due to output change in the numerator and productivity change due to input change in the denominator. In an Appendix the efficiency measure is extended to include any returns to scale pDDF.

Keywords: Data envelopment analysis; Proportional directional distance function; Efficiency measure; Malmquist productivity index

A Continuous Competitive Facility Location and Design Problem for Firm Expansion (2020), Springer Nature Switzerland, pp. 1013–1022,

Bogl ́arka G.-T ́oth (University of Szeged), Laura Anton-Sanchez (Miguel Hernández University), José Fernández (University of Murcia), Juana L. Redondo (University of Almería) and Pilar M. Ortigosa (University of Almería)

Abstract: A firm wants to expand its presence in a given geographical region. The available budget can be invested in opening a new facility and/or modifying the qualities of the existing firm-owned facilities. The firm can also close some of its existing facilities in order to invest the
money formerly devoted to them to its other facilities or to the new one (in case it is finally open). A MINLP formulation is proposed to model
this new problem. Both an exact interval branch-and-bound method and an ad-hoc heuristic are proposed to solve the model. Some computational results are reported

Keywords: Facility location; Competition; Quality; MINLP; Interval analysis; Heuristic

Customer eXperience: A Bridge Between Service Science and Human-Computer Interaction (2020), T. Ahram et al. (Eds.): IHSED 2019, AISC 1026, pp. 385–390.

Virginica Rusu (Universidad de Playa Ancha), Cristian Rusu (Pontificia Universidad Católica de Valparaíso), Federico Botella (Universidad Miguel Hernández de Elche), Daniela Quiñones (Pontificia Universidad Católica de Valparaíso), Camila Bascur (Pontificia Universidad Católica de Valparaíso) and Virginia Zaraza Rusu (Pontificia Universidad Católica de Valparaíso).

Abstract:  User eXperience (UX) and Usability are key concepts in Human-Computer Interaction (HCI). Customer eXperience (CX) is traditionally related to Service Science, but lately becomes a relevant topic in HCI. It offers a more comprehensive approach to the user as customer of several products, systems or services that a company offers. We focused for years our research on tourist as user of dedicated software systems and digital products. We are now focusing on tourist as customer, involving not only interactive software systems, but also the whole range of products and services that she or he interacts with. The paper examines CX as an extension of UX, and as a bridge between HCI and Service Science, focusing on tourist as customer.

Keywords: Customer experience; User experience; Service science; Tourism; Online travel agencies

Multi-objective evolutionary algorithms for a reliability location problem (2020), European Journal of Operational Research Volume 283, P. 83-93

Javier Alcaraz (University Miguel Hernández of Elche), Mercedes Landete (University Miguel Hernández of Elche), Juan F. Monge (University Miguel Hernández of Elche) and José L. Sainz-Pardo (University Miguel Hernández of Elche).

AbstractSome location problems with unreliable facilities present two different objectives, one consisting of minimizing the opening and transportation costs if none of the facilities fail and another consisting of minimizing the expected transportation costs. Usually, these different targets are combined in a single objective function and the decision maker can obtain some different solutions weighting both objectives. However, if the decision maker prefers to obtain a diverse set of non-dominated optimal solutions, then such procedure would not be effective. We have designed and implemented two multi-objective evolutionary algorithms for the realibility fixed-charge location problem by exploiting the peculiarities of this problem in order to obtain sets of solutions that are properly distributed along the Pareto-optimal frontier. The computational results demonstrate the outstanding efficiency of the proposed algorithms, although they present clear differences.

KeywordsLocation; Multi-objective location problems; Reliability models; Pareto frontier; Multi-objective evolutionary algorithms; Metaheuristics

Introducing cross-productivity: A new approach for ranking productive units over time in Data Envelopment Analysis (2020), Computers & Industrial Engineering Volume 144, 106456

Juan Aparicio (University Miguel Hernández of Elche), Lidia Ortiz (University Miguel Hernández of Elche), Jesus T. Pastor (University Miguel Hernández of Elche) and Jon M. Zabala-Iturriagagoitia (University of Deusto).

Abstract: Cross-efficiency has been developed for the evaluation of cross-sectional data in Data Envelopment Analysis. This paper extends cross-efficiency evaluation introducing the concept of cross-productivity. The extension proposed here is aimed at providing a dynamic peer-evaluation of decision making units, based on the standard Luenberger indicator, when the same set of units is observed over time. In particular, we show how to decompose the change in the ranking score of the different units into a component linked to catch-up and a term associated with technical change and innovation. As a result, we determine why the ranking provided by this novel cross-efficiency approach can vary period by period for the assessed set of units. Finally, the introduced cross-productivity approach is illustrated in the context of 28 national innovation systems in Europe, through the panel data included in the European Innovation Scoreboard for the years 2014 and 2015.

Keywords: Data Envelopment Analysis; Performance evaluation; Cross-efficiency; Productivity; Luenberger indicator; European Innovation Scoreboar