Luís M. S. Dias

Simulation as a tool for planning a material delivery system to manufacturing lines

This paper describes the procedures used during the planning of a material delivery system for the manufacturing lines of an electronic company. The paper describes the simulation experiments of a material delivery system for the manufacturing lines, using a logistic train. The main objective of this study is to make simulation experiments, regarding different amounts of equipment and logistic train programming methods, in order to identify and to propose changes that may lead to greater efficiency and precision of the logistic train functioning. The developed models were implemented with Arena simulation software. Experimental results are presented. Conclusions are discussed.

Solving the Team Orienteering Problem: Developing a Solution Tool Using a Genetic Algorithm Approach

Nowadays, the collection of separated solid waste for recycling is still an expensive process, specially when performed in large-scale. One main problem resides in fleet-management, since the currently applied strategies usually have low efficiency. The waste collection process can be modelled as a vehicle routing problem, in particular as a Team Orienteering Problem (TOP). In the TOP, a vehicle fleet is assigned to visit a set of customers, while executing optimized routes that maximize total profit and minimize resources needed. The objective of this work is to optimize the waste collection process while addressing the specific issues around fleet-management. This should be achieved by developing a software tool that implements a genetic algorithm to solve the TOP. We were able to accomplish the proposed task, as our computational tests have produced some challenging results in comparison to previous work around this subject of study. Specifically, our results attained 60% of the best known scores in a selection of 24 TOP benchmark instances, with an average error of 18.7 in the remaining instances. The usage of a genetic algorithm to solve the TOP proved to be an efficient method by outputting good results in an acceptable time.

Using simio for the specification of an integrated automated weighing solution in a cement plant

This paper focuses on the use of a discrete simulation tool (SIMIO) in the logistic system design of a cement plant. This research project specifies a proposal of using Discrete Event Simulation (DES) and innovative logistic methods for the correct specification of an integrated weighing solution in a cement plant. This specification will then help the design phase of the whole plant and will contribute for the rationalization of the use of cement plant resources. The proposed monitoring weighing system (Cachapuz - SLV Cement) together with the simulation model will evaluate different scenarios as far as the logistic system is concerned and will support important decisions in the design phase of a cement plant, contributing to the best use of the best set of resources.

Layout and process optimisation : using computer-aided design (CAD) and simulation through an integrated systems design tool

The design of production and logistic systems is a process of managing both technical and organisational variants in order to identify the best solution for a given system. This paper discusses design issues of production systems that are applied to an internal logistic system in the automotive industry. As far as the production systems design (PSD) is concerned, three basic classes of software tools usually pertain: computer-aided design (CAD), process simulation, and information systems. However, these software tools have been used with low levels of integration. Vik et al. (2010b, 2010c) proposed integrating these software resources in production systems and developed an advanced tool called integrated design of systems (IDS). The proposed IDS tool involves a wide set of functions for the most common tasks of PSD, from conceptualisation to implementation, including systems analysis (P-Q, cluster, and material flow analysis), automatic generation of simulation models, generation of alternatives for the layout of facilities and factories, material flows display, transportation system design, and iterative buffer size specification. The IDS approach takes advantage of simulation, CAD systems, and their integration. This paper will demonstrate the concept and functionalities of the proposed tool in a real industrial case study.

Non Emergency Patients Transport - A Mixed Integer Linear Programming

Fundacao para a Ciencia e Tecnologia; project GATOP - Genetic Algorithms for Team Orienteering Problem (Ref PTDC/EME- GIN/120761/2010), financed by national funds by FCT / MCTES, and co-funded by the European Social Development Fund (FEDER) through the COMPETE - Programa Operacional Fatores de Competitividade (POFC) Ref FCOMP-01-0124- FEDER-020609. This work has been partially supported by FCT – Fundacao para a Ciencia e Tecnologia within the Project Scope: PEst-OE/EEI/UI0319/2014 The authors would like to thank the NEOS Server at the University of Wisconsin in Madison for providing support to this study

Opinions on a car smoking ban: a needed guide for public health decision-makers

This study was supported through FEDER from the Operational Programme Factors of Competitiveness COMPETE and through national funding from the Foundation for Science and Technology FCT (Portuguese Ministry of Education and Science) (FCOMP-01-0124-FEDER-009117).

Micro Simulation to Evaluate the Impact of Introducing Pre-signals in Traffic Intersections

The resolution of problems related to the saturation of traffic intersections usually consists in the construction of infrastructure such as bridges or tunnels. These represent the most costly type of solutions. As such, it becomes necessary to ponder other types of solution, of lower cost. Thus, this paper intends to provide a way to significantly improve the performance of a traffic intersection, by using pre-signals, on its approaches. For this purpose, a traffic micro simulation model was developed, using Simio. The simulation experiments show that the implementation of pre-signals result in an increase of the intersection flows upper ceiling in over 10%, a decrease in the average waiting time per vehicle in 1 minute and a decrease of the queues average size. In addition, it was also found that there is always gain in the space occupied by the queues, taking into consideration the space investment needed to implement pre-signals.

Agent-Based Simulation to Assess the Performance of Intersections with Pre-signals: Comparison with Roundabouts

Solving traffic congestion problems in intersections is a complex logistic problem that usually consists in building infrastructures, such as bridges, tunnels, or roundabouts, which represent the costliest solutions. Concerning the case of roundabouts, many parameters influence its performance, e.g. geometry and size. Thus, other less costlier solutions should be pondered. This paper introduces a low-cost approach to traffic intersections, by using pre-signals; and conducts simulation experiments to verify if this approach could be used to improve the performance of traffic intersections. In this sense, an agent-based traffic simulation model was developed that applies the object modelling paradigm of Simio to model the individual behaviour of vehicles. The simulation experiments results indicate that the flow of vehicles can be increased up to 20%, reducing the average queue sizes and crossing time per vehicle and saving the fuel consumed up to 64%.

E-ducAtion: Multidisciplinary platform to support the teaching/learning process in Portuguese 1 st cycle schools

This work is focused on the development of a didactic platform to support the teaching/learning process in the 1st cycle of Portuguese education program. The platform has practical examples that should promote the competences taught in four areas: Mathematics, Portuguese, Science, and English. The specifications and the learning objectives were defined by the teachers and the research team. The final goal of this didactic tool is to motivate students to learn in a friendly way and to overcome the difficulties that some students have. In this paper are presented the requisites, the design and the implementation of the platform.

Inverted pendulum controlled by an analog PID controller: a framework for a laboratorial experiment

This paper presents the design of a framework for a didactic kit for control studies based on a rotary inverted pendulum. One of the challenges was to involve students in the design of the platform. This first version of the kit was developed by students of the Integrated Master on Industrial Electronics and Computers Engineering at the University of Minho. It considers the design and implementation of the control of the angular position of an inverted pendulum through an analog Proportional, Integral and Derivative (PID) controller. This Single Input Single Output (SISO) control system allows retrieving the equilibrium position of the pendulum when it is subjected to disturbances.