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- Ant colony optimization routing mechanisms with bandwidth sensingPublication . Mapisse, J. M.; Cardoso, Pedro J. S.; Monteiro, J. M.The study and understanding of the social behavior of insects has contributed to the definition of some algorithms that are capable of solving several types of optimization problems. In 1997 Di Caro and Dorigo developed the first routing algorithm for wired networks, called AntNet, using an approach which was inspired in the behavior of ant colonies. At each node, AntNet, similar to others Ant Colony Optimization (ACO) based algorithms, forward ants based in the amount of pheromones present in the links and in response to the node's queue lengths. In this paper, an adaptation of the e-DANTE algorithm for discrete problems, as an IP based routing mechanism, was implemented. We also propose the inclusion of a new parameter for the computation of paths for both the AntNet and the newly proposed algorithm: the available bandwith. Those methods were tested in ns-2 using two dense network architectures and their efficiency is compared with the original AntNet and a Link-State routing algorithm, when considering the transmission of competing traffic flows between distinct nodes. © 2011 IEEE.
- A solution for a real-time stochastic capacitated vehicle routing problem with time windowsPublication . Cardoso, Pedro J. S.; Schütz, Gabriela; Mazayev, Andriy; Ey, Emanuel; Corrêa, TiagoReal-time distribution planning presents major difficulties when applied to large problems. Commonly, this planning is associated to the capacitated vehicle routing problem with time windows (CVRPTW), deeply studied in the literature. In this paper we propose an optimization system developed to be integrated with an existing Enterprise Resource Planning (ERP) without causing major disruption to the current distribution process of a company. The proposed system includes: a route optimization module, a module implementing the communications within and to the outside of the system, a non-relational database to provide local storage of information relevant to the optimization procedure, and a cartographic subsystem. The proposed architecture is able to deal with dynamic problems included in the specification of the project, namely: arrival of new orders while already optimizing as well as locking and closing of routes by the system administrator. A back-office graphical interface was also implemented and some results are presented.
- Artificial intelligence applications and innovations: day-to-day life impactPublication . Rodrigues, João; Cardoso, Pedro; Chinnici, MartaThe idea of an intelligent machine has fascinated humans for centuries. But what is intelligence? Some define it as the capacity for learning, reasoning, understanding or, from a different perspective, the aptitude to grasp truths, relationships, facts, or meanings. All these perspectives require the capacity to acquire data from the surrounding world and, possibly, act over that environment. In short, the building of more or less autonomous agents, served with sensors and actuators, capable of learning and producing educated answers has been long foreseen. New trends in intelligente systems comprise, among other aspects, pervasive robotization, ubiquitous online data access, empowered edge computing, smart spaces, and digital ethics. These trends build the research on “Artificial Intelligence Applications and Innovation”, impacting our day-to-day life, our cities, and even our free time. Nevertheless, artificial intelligence (AI) is still closely associated with some popular misconceptions that cause the public to either have unrealistic fears about it or to have unrealistic expectations about how it will change our workplace and life in general. It is important to show that such fears are unfounded and that new trends, innovations, technologies, and smart systems will be able to improve the way we live, benefiting society without replacing humans in their core activities.
- Mobile five senses augmented reality system: technology acceptance studyPublication . Rodrigues, João; Ramos, Celia; Pereira, Joao A. R.; Sardo, Joao D. P.; Cardoso, PedroThe application of the most recent technologies is fundamental to add value to tourism experiences, as well as in other economic sectors. Mobile Five Senses Augmented Reality (M5SAR) system is a mobile guide instrument for cultural, historical, and museum events. In order to realize the proclaimed five senses, the system has two main modules: a (i) mobile application which deals mainly with the senses of sight and hearing, using for that the mobile device camera to recognize and track on-the-fly (museum's) objects and give related information about them; and a (ii) portable device capable of enhancing the augmented reality (AR) experience to the full five senses through the stimulus of touch, taste, and smell, by associating itself to the users' smartphone or tablet. This paper briefly presents the system's architecture but, the main focus is on the analysis of the users' acceptance for this technology, namely the AR (software) application, and its integration with the (hardware) device to achieve the five senses AR. Results show that social influence, effort expectancy, and facilitating conditions are the key constructs that drive the users to accept and M5SAR's technology.
- Anomaly detection of consumption in Hotel Units: A case study comparing isolation forest and variational autoencoder algorithmsPublication . Mendes, Tomás; Cardoso, Pedro; Monteiro, Jânio; Raposo, JoãoBuildings are responsible for a high percentage of global energy consumption, and thus, the improvement of their efficiency can positively impact not only the costs to the companies they house, but also at a global level. One way to reduce that impact is to constantly monitor the consumption levels of these buildings and to quickly act when unjustified levels are detected. Currently, a variety of sensor networks can be deployed to constantly monitor many variables associated with these buildings, including distinct types of meters, air temperature, solar radiation, etc. However, as consumption is highly dependent on occupancy and environmental variables, the identification of anomalous consumption levels is a challenging task. This study focuses on the implementation of an intelligent system, capable of performing the early detection of anomalous sequences of values in consumption time series applied to distinct hotel unit meters. The development of the system was performed in several steps, which resulted in the implementation of several modules. An initial (i) Exploratory Data Analysis (EDA) phase was made to analyze the data, including the consumption datasets of electricity, water, and gas, obtained over several years. The results of the EDA were used to implement a (ii) data correction module, capable of dealing with the transmission losses and erroneous values identified during the EDA’s phase. Then, a (iii) comparative study was performed between a machine learning (ML) algorithm and a deep learning (DL) one, respectively, the isolation forest (IF) and a variational autoencoder (VAE). The study was made, taking into consideration a (iv) proposed performance metric for anomaly detection algorithms in unsupervised time series, also considering computational requirements and adaptability to different types of data. (v) The results show that the IF algorithm is a better solution for the presented problem, since it is easily adaptable to different sources of data, to different combinations of features, and has lower computational complexity. This allows its deployment without major computational requirements, high knowledge, and data history, whilst also being less prone to problems with missing data. As a global outcome, an architecture of a platform is proposed that encompasses the mentioned modules. The platform represents a running system, performing continuous detection and quickly alerting hotel managers about possible anomalous consumption levels, allowing them to take more timely measures to investigate and solve the associated causes.
- A decision-support system to Analyse Customer Satisfaction Applied to a Tourism Transport ServicePublication . Ramos, Celia; Cardoso, Pedro; Fernandes, Hortênsio C. L.; Rodrigues, JoãoDue to the perishable nature of tourist products, which impacts supply and demand, the possibility of analysing the relationship between customers’ satisfaction and service quality can contribute to increased revenues. Machine learning techniques allow the analysis of how these services can be improved or developed and how to reach new markets, and look for the emergence of ideas to innovate and improve interaction with the customer. This paper presents a decision-support system for analysing consumer satisfaction, based on consumer feedback from the customer’s experience when transported by a transfer company, in the present case working in the Algarve region, Portugal. The results show how tourists perceive the service and which factors influence their level of satisfaction and sentiment. One of the results revealed that the first impression associated with good news is what creates the most value in the experience, i.e., “first impressions matter”..
- LifeSpeeder: a web and mobile platform for events locationPublication . Cardoso, Pedro J. S.; Monteiro, J. M.; Dos Santos, J.; Baeza, N.; Tarazona, S.The use of smartphones and tablets as become almost banal in these days. Smartphones, besides serving their main purpose of making and receiving calls, come to be one of the main equipments to obtain information from the Internet, using the commonly installed browsers or through the use of dedicated applications. Furthermore, several other devices are also very frequent to the majority of the modern smartphones and tablets in the market (e.g., GPS - Global Positioning System). This devices give the current systems a very high potential of usage. One example of applicability, comes from the wish to find and navigate to events or activities which are or will soon be occurring near the user. The LifeSpeeder platform is one of the first applications in the mobile equipment market of applications which take into consideration exactly what we have just outlined, i.e., a mobile and desktop application which allows the users to locate events according with their preferences and to get help navigating to them. In this paper we briefly describe the LifeSpeeder's front and back-end. © 2014 Springer International Publishing.
- Ant colony algorithms for multiple objective combinatorial optimization: applications to the minimum spanning trees problemsPublication . Cardoso, Pedro J. S.The study of meta-heuristic solutions based on the Ant Colony Optimization (ACO) paradigm for the Multiple Objective Minimum Spanning Trees and related combinatorial problems is the main concern of this investigation. In the commonly accepted complexity scale for problems, the Multiple Objective Minimum Spanning Trees is rated as an $\NP$-complete problem. Furthermore, as in the generality of the multiple objective optimization problem, the solution of the Minimum Spanning Trees case is a set of trade-off solutions in the sense that to improve one of the objectives it is necessary to worse at least one of the others, which is a major concern in a practical point of view. In the first part of the investigation, a theoretical analysis of the problem is made to complement the known results. This analysis corroborates the fact that in practice the use of exact methods to solve the Multiple Objective Minimum Spanning Trees problems is only applied in specific circumstances. This implies that to solve the problem an approximation method must be considered as an alternative. In particular, two methods based on the ACO paradigm are proposed: the Multiple Objective Network optimization based on an ACO (MONACO) and the $\epsilon$-Depth ANT Explorer (e-DANTE). The MONACO method uses a set of pheromone trails and specific heuristics to approximate the Pareto set. The e-DANTE method is an improvement of the MONACO method that uses a depth search procedure, based on the best performing solutions, to deeply exploit the search space. The proposed methods are tested with selected multiple objective problems, improving the results previously obtained by other authors. To test the MONACO and e-DANTE algorithms over the Multiple Objective Minimum Spanning Trees problem is proposed a library/repository of multiple objective network problems established over a systematized set of networks generators. The results obtained with MONACO and e-DANTE are then compared with the results obtained with a Brute Force and the Weighted Sum method.
- Framework for the characterization of hotel websitesPublication . Correia, Marisol B.; Ramos, Célia M. Q.; Rodrigues, J. M. F.; Cardoso, Pedro J. S.Nowadays the importance of websites to the tourism and hospitality industries is fundamental. Hotels, for instance, spend a huge amount of money improving their websites to show all the activities and amenities that they can provide. There are studies to evaluate website performance based on functionality, usability and other factors; nevertheless, they are not exhaustive. This paper presents a framework for the characterization of hotel and resort websites, that was applied as a case study to the websites of 5-star hotels and resorts that operate in the tourism region of the Algarve, Portugal. This framework allows us to identify a set of features for the hotel and resort websites characterization. From these features, we propose a set of comprehensive indicators, grouping them into ten fundamental information dimensions, as well as the application of these indicators and information dimensions, which allows obtaining quantitative and qualitative results.
- Augmented reality and holograms for the visualization of mechanical engineering partsPublication . Figueiredo, Mauro; Cardoso, Pedro J. S.; Gonçalves, C. D. F.; Rodrigues, J. M. F.There is an increasing number of students using tablets in schools. Mobile devices gained popularity as an educational tool and there are many schools that use them frequently in educational activities to improve learning. We found that first year students of mechanical engineering in general have difficulties in understanding 3D shapes from 2D views. There are many Augmented Reality (AR) applications available that can be used to create educational contents for these mobile devices. On the other hand, there is an increasing interest in making holograms. In this paper we studied the most popular AR systems and show examples of using an AR system for the visualization of 3D models. We also present the creation of a low cost prototype, the EducHolo, that enables the visualization of holograms supported by tablets. With this prototype students can visualize the hologram of mechanical parts, providing a better perception of the model 3D shape and improving the ability of making the 2D orthographic views and perspectives that they study in the first year of mechanical engineer.