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The User Centered Design methodology consists of an iterative cycle of analysis, ideation, prototyping, and evaluation. In this context, heuristic evaluations are valuable tools to identify usability problems in an interface from the earliest stages of design. However, there are few well-defined heuristics for Virtual Environments. Based on this, the objective of this research is to verify and improve...
In the paper, a characterization of the 868 MHz off-body radio channel in BANs is presented. Measurements were carried out in a ferry environment using a specific set-up. A method for path loss using radio distance measurements (RDMs) was developed. It allows to automate the measurements process and make it independent from the variable speed of a moving person. Based on the observed path loss as...
In this paper a detailed analysis of slow and fast fading effects in container terminal environments is presented, fading distribution parameters are evaluated and an analytical model is proposed. The model is composed of a set of analytical equations allowing to evaluate fading statistical distribution parameters for different system and environments conditions. Globally, it is observed that for...
This paper presents an off-body radio channel measurements in a ferry passenger cabin at 2.45 GHz band, for static sleeping scenarios with different body orientation and on-body antennas placements, and also for upper and lower sleeping berths. The measurements have been performed with two types of on-body wearable receiving antennas: FlexPIFA (flexible planar inverted F antenna), and FlexNotch (flexible...
Multiplayer Online Battle Arena (MOBA) games are very popular in the current eSport scenario, being highlighted in several competitions around the world. However, the domain of knowledge contained in these games is large, which makes it difficult to discover and predict the course of a match. The present work proposes the application of classification algorithms to determine the team with more chances...
Social networks are of significant analytical interest. This is because their data are generated in great quantity, and intermittently, besides that, the data are from a wide variety, and it is widely available to users. Through such data, it is desired to extract knowledge or information that can be used in decision-making activities. In this context, we have identified the lack of methods that apply...
This paper proposes a model for radio resource management in virtualised radio access networks, based on the criterion of proportional fairness, which is also adapted to deal with the situations when there is not enough capacity to serve all subscribers with an acceptable level of service, the so-called the extreme case. A single virtual network operator providing four different classes of services...
The process of Knowledge Discovery in Databases, or KDD for short, have been intensively used in tasks focused on searching useful information based on data. The reason is that such data is generated in significant volume, high speed and with a large variety, which makes it require accurate, efficient and scalable methods to handle them. Due to this scenario, several tools and methodologies have been...
The volume of data exchanged by computer networks is gradually increasing over time, which provides the need for performance and interoperability between different platforms and systems. In this line, there are several studies dedicated to service-oriented software architectures and resource consumption models. However, a few of them are focused on the development of generic tools for the dynamic...
This paper presents an analysis of the polarisation characteristics for the channel in dynamic off-body communications, and an empirical channel model, based on measurements performed at 2.45 GHz in an office environment. Body presence and propagation conditions have a strong influence on signal depolarisation. The model assumes three components for the total path loss: mean path loss, represented...
This paper presents an approach to the estimation of mean path loss model parameters in off-body Body Area Networks channels. In this approach, the path loss exponent is constrained to a value obtained from line-of-sight (LoS) propagation in the copolarised channel, considering a generalised static scenario. The proposed approach is compared to alternative ones, by evaluating the coefficient of determination...
The easyPET concept proposed here, protected under a patent by the University of Aveiro, aims to realize a simple and affordable small dimension Positron Emission Tomography (PET) scanner. This innovative system is based on a single pair of detectors and a rotating mechanism with two degrees of freedom reproducing the functionalities of an entire PET ring. A 2D imaging prototype has been designed,...
This paper addresses the analysis of LTE performance in order to assess the quality of data services provided by the network. Models were developed in order to characterise and analyse a sample of experimental measurements from a large service area of an operator's network. These models and algorithms establish a statistical classification for the cells, enabling a proper analysis of the quality of...
This work presents a study concerning the impact of Cloud Radio Access Network and virtualisation techniques in an operator's network, namely in terms of the necessary number of storage and processing nodes, and the links in between, taking increasingly network constraints into account (e.g., latency) as well as deployment ones (e.g., service area, deployment strategy, and expected proliferation of...
This paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were...
This paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location...
The use of wearable devices, like smartwatches and smartglasses, with wireless communication capabilities are now becoming common. The use of such devices, radiating electromagnetic waves close to the human body, is also becoming a matter of concern. The SAR assessment of Google Glasses for 0.9 GHz, 1.94 GHz, 2.43 GHz and 2.6 GHz bands, corresponding to cellular (GSM, UMTS and LTE) and wireless (Wi-Fi),...
Selective Laser Sintering (SLS) is an important branch of additive manufacturing ("3D printing") technologies. The SLS machines are processing powders so that they are selectively sintered by a CO2 or Nd:YAG laser beam. The SLS process was initially developed to produce polymer-based components. Then, SLS had a breakthrough toward the producing of structurally perfect parts directly from...
This paper presents an off-body fading channel model for Body Area Networks. The proposed model, based on both simulations and measurements at 2.45 GHz in a realistic indoor environment, consists of three components: mean path loss, body shadowing, and multipath fading. The first is modelled as a log function of distance, the path loss exponent being in between 0.4 and 1.6. A statistical perspective...
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