Untitled

Funder

Organizational Unit

Publications

Hybrid system for simultaneous job shop scheduling and layout optimization based on multi-agents and genetic algorithm

Publication . Alves, Filipe; Varela, Maria Leonilde R.; Rocha, Ana Maria A.C.; Pereira, Ana I.; Barbosa, José; Leitão, Paulo

A challenge is emerging in the design of scheduling support systems and facility layout planning, both for manufacturing environments where dynamic adaptation and optimization become increasingly important on the efficiency and productivity. Focusing on the interactions between these two problems, this work combines two paradigms in sequential manner, optimization techniques and multi-agent systems, to better reflect practical manufacturing scenarios. This approach, in addition to significantly improve the quality of the solutions, enables fast reaction to condition changes. In such stochastic and very volatile environments, the manufacturing industries, the fast rescheduling, or planning, are crucial to maintain the system in operation. The proposed architecture was codified in MatLab and NetLogo and applied to a real-world job shop case study. The experimental results achieved optimized solutions, as well as in the responsiveness to achieve dynamic results for disruptions and simultaneously layout optimization

2020Conference object

Open access

Improving efficiency of a multistart with interrupted hooke-and-jeeves filter search for solving MINLP problems

Publication . Fernandes, Florbela P.; Costa, M. Fernanda P.; Rocha, Ana Maria A.C.; Fernandes, Edite M.G.P.

This paper addresses the problem of solving mixed-integer nonlinear programming (MINLP) problems by a multistart strategy that invokes a derivative-free local search procedure based on a filter set methodology to handle nonlinear constraints. A new concept of componentwise normalized distance aiming to discard randomly generated points that are sufficiently close to other points already used to invoke the local search is analyzed. A variant of the Hooke-and-Jeeves filter algorithm for MINLP is proposed with the goal of interrupting the iterative process if the accepted iterate falls inside an ϵ-neighborhood of an already computed minimizer. Preliminary numerical results are included.

2016Conference object

Open access

The relationship between smart cities and the internet of things in low density regions

Publication . Lopes, Isabel Maria; Guarda, Teresa

In these times of digital transformation, cities have overcome the challenges of the past and are building the future. The use of technological resources as a means of efficiently delivering various services and improving citizens’ quality of life has transformed regions and cities into smart regions and cities. There have been a remarkable amount of projects implemented by the Municipalities in the last years, taking the technologies to the cities. However, for a project to be interesting, it must have a positive impact on society, that is, citizens. This evidence gave rise to the present study whose goal was to find out if citizens living in inner cities, labeled as smart cities, actually consider them that way, and whether their city uses innovative solutions that optimize their daily lives. The results are discussed in the light of the literature and future work is identified with the aim of shedding some light on a field as emerging, promising and current as this of Intelligent Cities and the Internet of Things.

2018Conference object

Open access

Architecture of information security policies: a content analysis

Publication . Lopes, Isabel Maria; Oliveira, Pedro

The growing importance that Information Systems (IS) have in our companies naturally brings about a need to rely and trust in their use. There are a number of technologies which help ensure the security and trust in the IS use. However, technology alone does not solve all the problems, which is why there is a need for well-defined information systems security policies in order to ensure the data integrity and confidentiality. Nevertheless, there is a lack of information concerning the contents that such policies must have. This work aims to contribute to the filling of this gap. It presents a synthesis of the literature on information security policies content and it characterizes 15 Small and Medium Sized Enterprises (SMEs) information security policy documents as far as their features and components are concerned. The content analysis (CA) research technique was applied to characterize the information security policies. The profile of the policies is presented and discussed and propositions are made for possible future works.

2016Conference object

Open access

Applying attribute grammars to teach linguistic rules

Publication . Barros, Patrícia; Pereira, Maria João; Henriques, Pedro Rangel

An attribute grammar is a very well known formalism to describe computer languages but it can also be successfully used to describe linguistic phenomena. Since natural languages can also be expressed in grammars it is natural to describe rules using the same formalism. Linguistic teachers of the University Complutense of Madrid started using attribute grammars but they lack a tool that helps them to specify linguistic rules in a friendly and natural way. Therefore we propose a domain specific language (NLSdsl) carefully designed for non-programmers that will be implemented on an AnTLR based system.

2017Conference object

Open access