2017
Authors
Soares, M; Viana, P;
Publication
RECENT ADVANCES IN INFORMATION SYSTEMS AND TECHNOLOGIES, VOL 1
Abstract
In movie/TV collaborative recommendation approaches, ratings users gave to already visited content are often used as the only input to build profiles. However, users might have rated equally the same movie but due to different reasons: either because of its genre, the crew or the director. In such cases, this rating is insufficient to represent in detail users' preferences and it is wrong to conclude that they share similar tastes. The work presented in this paper tries to solve this ambiguity by exploiting hidden semantics in metadata elements. The influence of each of the standard description elements (actors, directors and genre) in representing user's preferences is analyzed. Simulations were conducted using Movielens and Netflix datasets and different evaluation metrics were considered. The results demonstrate that the implemented approach yields significant advantages both in terms of improving performance, as well as in dealing with common limitations of standard collaborative algorithm.
2017
Authors
Nabizadeh, AH; Jorge, AM; Leal, JP;
Publication
ADJUNCT PUBLICATION OF THE 25TH CONFERENCE ON USER MODELING, ADAPTATION AND PERSONALIZATION (UMAP'17)
Abstract
Nowadays using E-learning platforms such as Intelligent Tutoring Systems (ITS) that support users to learn subjects are quite common. Despite the availability and the advantages of these systems, they ignore the learners' time limitation for learning a subject. In this paper we propose RUTICO, that recommends successful learning paths with respect to a learner's knowledge background and under a time constraint. RUTICO, which is an example of Long Term goal Recommender Systems (LTRS), a.er locating a learner in the course graph, it utilizes a Depth-first search (DFS) algorithm to find all possible paths for a learner given a time restriction. RUTICO also estimates learning time and score for the paths and finally, it recommends a path with the maximum score that satisfies the learner time restriction. In order to evaluate the ability of RUTICO in estimating time and score for paths, we used the Mean Absolute Error and Error. Our results show that we are able to generate a learning path that maximizes a learner's score under a time restriction. © 2017 ACM.
2017
Authors
Leao, E; Montez, C; Moraes, R; Portugal, P; Vasques, F;
Publication
SENSORS
Abstract
The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network.
2017
Authors
Pascoal, A; Gonçalves, J; Braz César, M;
Publication
COMPDYN 2017 - Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering
Abstract
Typical vehicle suspension systems are based on passive energy dissipation devices. This type of systems have proven to be a reliable and economic approach, however they are not capable to modify its behavior in accordance with the road conditions. On the other hand, active systems allow a continuous control of the suspension response although requiring sensors, actuators and controllers which represents a more complex and expensive system, usually demanding high power requirements. A middle-term vibration control approach is to use the so-called semi-active systems with the adaptability of active systems and lower energy consumption. This paper aims to evaluate the comfort ridding of a full suspension bicycle equipped with semi-active open loop controlled suspension system using a magneto-rheological (MR) damper. The assessment was carried out based on the analysis of real data, extracted from the instrumented bicycle prototype. The experimental tests were made in a smooth indoor pavement and a cobblestone road. Finally, the results obtained with the proposed semi-active suspension control system are presented and discussed.
2017
Authors
Giesteira, B; Mesquita, J; Fernandes, M; Silva, A;
Publication
International Journal of Interdisciplinary Social and Community Studies
Abstract
The ISOTYPE (International System of Typographic Picture Education) pictograms, a system that emerged as a response to a society driven by science and industrialization, as well as imbued with the belief that the modern spirit had what it takes to pursue the universal theories: The will to do a "utopia" universal communication. Otto Neurath (1882- 1945), developed the isotype in the early 20s of twentieth century, with the help of Gerd Arntz (1900-1988) and Marie Neurath (1898-1986). The frame used simplified forms to transmit social and economic information to the general public and applied in museums, books, posters, and educational material. Neurath hoped to create a global standard for education and unite humanity through an ordered, and universally readable language of vision. Their core principles: reduction, to determine the individual style signs; consistency, to give the whole an appearance of a coherent system. The reduction suggests that the "image has a natural, scientific relationship to its object" (Lupton 1989, 54), and formal consistency is linked to mass production, enabling the user to create a habit of how the information is presented. However, isotype did not advance "because of the difficulties related to the sheer size and complexity of the iconic representation" (Rajamanickam, 2005, 7) and tend to ignore the socio-economic and cultural contexts. The creation of language should rely on the context. And considering the context, currently, many of the 17 million Europeans who suffer from food allergies could benefit from a more direct information system in the identification of the fourteen allergens regulated by the Parliament and Council Regulation (EU) n° 1169/2011 in food products' packages. This study is aimed at creating pictograms representing these fourteen allergens along visual and tactile lines, through relief printing. Based on an Inclusive Design approach, the project is meant to overcome restrictions such as sight impairment or illiteracy. Making use of User Centered Design (UCD) methodology, and with the support of the SAED (Disabled Students Support Services of the University of Porto) and GAENEE-UP (Support Office for Students with Special Educational Needs of the University of Porto), it employed field observation processes, in which potential users recorded their tactile perception of the basic elements of visual communication. The result is the creation of a universal code, which is meant to satisfy the expectations and needs of potential users, namely people with impaired sight with a framework that systematize guidelines to support the development of new relief pictograms in the food allergies context. This project was developed with the purpose of creating a unique and universal code that could help two special groups of disabled people: Those,both adults and children, that suffer from food allergies and the visually impaired. The leading goal was the creation of relief signs that represent the fourteen allergens regulated by the European Union, under the Parliament and Council (EU) Regulation n° 1169/2011, as well as the development of a guideline framework to support future relief pictograms' designs. In this paper we explain the process of creating those, presenting some of the results, semiotic and technical requirements that underlie the framework that systematize the relief pictograms guidelines to visual impaired users. © Common Ground Research Networks, Bruno Giesteira, João Mesquita.
2017
Authors
Teixeira, FB; Oliveira, T; Lopes, M; Leocadio, C; Salazar, P; Ruela, J; Campos, R; Ricardo, M;
Publication
OCEANS 2017 - ABERDEEN
Abstract
The growth of the Blue Economy has been boosted by a set of traditional and new activities including maritime transportation, fisheries, environmental monitoring, deep sea mining, and inspection missions. These activities are urging for a cost-effective broadband communications solution capable of supporting both above and underwater missions at remote ocean areas, since many of them rely on an ever-increasing number of Autonomous Surface Vehicles (ASV), Autonomous Underwater Vehicles (AUV) and Remote Operated Vehicles (ROV), which need to transmit large amounts of data to shore. The BLUE-COM+ project has considered the usage of helium balloons to increase the antenna height, and overtake the earth curvature and achieve Fresnel zone clearance, combined with the use of sub-GHz frequency bands to enable long range communications. In this paper we present the results obtained in three sea trials. They show that the BLUECOM+ architecture is capable of supporting human and system activities at remote ocean areas by enabling Internet access beyond 50 km from shore, live video conference calls with the quality of experience available on land, and real-time data upload to the cloud by ASVs, AUVs and ROVs using standard access technologies with bitrates above 1 Mbit/s.
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