Browsing by Author "Aguiar, Ana"
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- Adulteração de suplementos alimentares por fármacos sintéticosPublication . Aguiar, Ana; Lima, Rita; Terroso, Sofia; Correia, Patrícia Carla dos SantosOs suplementos alimentares estão em constante expansão no mercado mundial, uma vez que a população em geral recorre cada vez mais à toma destes com os mais variados objetivos (Ribeiro, 2015). No entanto, nos últimos anos a adulteração de suplementos alimentares com compostos farmacologicamente ativos tem vindo a agravar-se. O principal objetivo deste projeto visou analisar e comparar os diferentes métodos analíticos descritos na literatura e expressar as quantidades detetadas de cada fármaco sintético nos suplementos alimentares para perda de peso, aumento da massa muscular e disfunção erétil.
- Characterization and Modeling of the Bicycle-Antenna System for the 2.4GHz ISM BandPublication . Pinto, Luis; M. Santos, Pedro; Almeida, Luis; Aguiar, AnaVehicular communication is rapidly becoming a standard reality, and precise models are necessary for accurate performance estimates. Alongside cars and trucks, smaller vehicles such as scooters and bicycles are also set to participate in V2X networking, but have received considerably less attention. In this work, we present an extensive characterization of the gain pattern of a bicycle and antenna system for the IEEE 802.11g standard. We measure the radiation patterns of the antenna of a commodity 2.4 GHz WiFi module mounted on six distinct positions on the body of six archetypal bicycles in an anechoic chamber. The RSSI sample set per angle and antenna position is characterized statistically and input into an empirical model of the gain pattern of the bicycle-antenna system. We define a bicycle-to-X propagation model that pairs the proposed bicycle-antenna gain and a log-distance shadowing path loss model, and conduct outdoor measurement campaign for evaluation. We observe that the gain model measured in chamber matches the measured RSSI at small distances, whereas at larger distances it provides less accuracy.
- Cooperative Bicycle Localization System via Ad Hoc Bluetooth NetworksPublication . Santos, Pedro Miguel; Rosa, Vera; Pinto, Luis; Aguiar, AnaBicycles are becoming increasingly more equipped with embedded connected devices, by design or through after market products, to support applications such as fitness monitoring and tracking. Bluetooth (BT) and BT Low Energy (BLE) technology is often embedded in such devices to support connectivity to a personal mobile device or a dock, when parked. BT/BLE transmit periodic beacons for node discovery that can be explored for V2X applications, such as safety and fleet management. We present a distributed system that explores periodic BT beacons sent by a module embedded in a bicycle to opportunistically locate nodes of interest (NOI). We address the particular application of stolen bicycle detection. In a scenario in which a bicycle is stolen and has its communication system tampered with but BLE remains functional, a service provider (e.g., fleet operator, authorities) is informed of this new NOI and shares an updated NOI list with the NOI detection-enabled bicycles. In turn, the bicycles flag contacts with stolen bicycles to the provider backoffice, at the earliest convenience (depending on available communications interfaces: immediately if cellular is available, or opportunistically when passing by a dock). We describe the operation and software architecture of the system, and an actual implementation in COTS equipment. Experimental measurements of the communication range and a demonstration of the system for oroof-of-concept are also reported.
- Determination of the radiochemical purity of 99mTc-Tetrofosmin: comparision between five methodsPublication . Aguiar, Ana; Oliveira, Marta; Teixeira, Dalila; Cunha, Lídia; Metello, Luís F.GOAL: The manufacturing and distribution of strips of instant thin - layer chromatography with silica gel (ITLC - SG) (reference method) is currently discontinued so there is a need for an alternative method f or the determination of radiochemical purity (RCP) of 99m Tc - tetrofosmin. This study aims to compare five alternative methods proposed by the producer to determine the RCP of 99m Tc - tetrofosmin. METHODS: Nineteen vials of tetrofosmin were radiolabelled with 99m Tc and the percentages of the RCP were determined. Five different methods were compared with the standard RCP testing method (ITLC - SG, 2x20 cm): Whatman 3MM (1x10 cm) with acetone and dichloro - methane (method 1); Whatman 3MM (1x1 0 cm) with ethyl acetate (method 2); aluminum oxide - coated plastic thin - layer chromatography (TLC) plate (1x10 cm) and ethanol (method 3); Whatman 3MM (2x20 cm) with acetone and dichloro - methane (method 4); solid - phase extraction method C18 cartridge (meth od 5). RESULTS: The average values of RCP were 95,30% ± 1,28% (method 1), 93,95 ± 0,61% (method 2), 96,85% ± 0,93% (method 3), 92,94% ± 0,99% (method 4) and 96,25% ± 2,57% (method 5) (n=12 each), and 93,15% ± 1,13% for the standard method (n=19). There we re statistical significant differences in the values obtained for methods 1 (P=0,001), 3 (P=0,000) and 5 (P=0,004), and there were no statistical significant differences in the values obtained for methods 2 (P=0,113) and 4 (P=0,327). CONCLUSION: From the results obtained, methods 2 and 4 showed a higher correlation with the standard method. Unlike method 4, method 2 is less time - consuming than the reference method and can overcome the problems associated with the solvent toxicity. The remaining methods (1, 3 and 5) tended to overestimate RCP value compared to the standard method.
- Experimental Evaluation of Urban Points-of-Interest as Predictors of I2V 802.11 Data TransfersPublication . Santos, Pedro M.; M. Sousa, Luís; Aguiar, AnaSmart Cities will leverage the Internet-of-Things (IoT) paradigm to enable cyber-physical loops over urban processes. Vehicular backhauls contribute to IoT platforms by allowing sensor/actuator nodes near roads to explore opportunistic connections to passing vehicles when other communication backhauls are unavailable. A placement process of nodes that includes vehicular networks as a connectivity backhaul requires estimates of infrastructure-to-vehicle (I2V) wireless service at potential deployment sites. However, carrying out I2V measurement campaigns at all potential locations can be very expensive; so, predictive models are necessary. To this end, qualitative characteristics of a potential site, such as infrastructural points-of-interest (POI) relating to traffic (i.e., traffic lights, crosswalks) and fleet activities (i.e., bus stops, garbage bins) can inform about the vehicles' mobility patterns and quality of the I2V service. In this paper, we show the contribution of POI (and site-specific information) to I2V transfers, leveraging a real-world dataset of geo-referenced I2V WiFi link measurements in urban settings. We present the distributions of throughput with respect to distance per POI class and site, and apply exponential regression to obtain practical throughput/distance models. We then use these models to compare I2V transfer estimation methodologies with different levels of POI-specific data and data resolution. We observe that I2V transfer estimate accuracy can improve from an average over-estimation of 18.3% with respect to measured values, if site or POI-specific information metrics are not used, to 9.3% in case such information is used.
- Feasibility of Gateway-Less IoT E-Health ApplicationsPublication . Pereira, Carlos; Guimarães, Diana; Mesquita, João; Santos, Frederico; Almeida, Luis; Aguiar, AnaMachine-to-Machine (M2M) communications are a key enabler of Internet of Things (IoT) applications. One domain with growing interest in M2M/IoT is e-health, either for self-monitoring, home monitoring, or hospital systems. However, current sensing devices in this domain rely on short-range communication protocols that require a gateway (GW) for Internet connection. Smartphones have been proposed as GWs in mobile M2M communications due to their enhanced connectivity and sensing capabilities. However, the GW functionality impacts on the smartphone usability, causing undesirable battery depletion and the smartphone itself increases the overall cost of e- health solutions. In this work, we propose converging e-health devices and Wi-Fi towards direct Internet access through the existing Wi-Fi infrastructure and by-passing current GWs. We use recent low-cost ultra low-power Wi-Fi modules and feature them with M2M capabilities supporting their integration in an interoperable e-health framework. We present results on end-to-end latency and power requirements within a concrete e-health use case that show the feasibility of the proposed GW-less solution.
- A Glimpse at Bicycle-to-Bicycle Link Performance in the 2.4GHz ISM BandPublication . Santos, Pedro M.; Pinto, Luis; Aguiar, Ana; Almeida, LuisBicycle-to-bicycle (Bi2Bi) communication can be implemented by well-established technologies in the 2.4GHz ISM band: IEEE 802.11, Bluetooth or IEEE 802.15.4. These technologies have distinct performance due to different physical and data link layers. In this paper, we characterize the mentioned 2.4 GHz-operating technologies over opportunistic links established between bicycles using commodity hardware. We find that, in Bi2Bi links, Blue-tooth, IEEE 802.11 at 24 Mbit/s, and IEEE 802.11 with automatic rate adaptation can communicate only in the immediate surroundings (under 15m of range), to maxima of 1.5 Mbit/s, 17 Mbit/s and 25 Mbit/s, respectively. IEEE 802.15.4 and IEEE 802.11 at 1 Mbit/s sustain connectivity up to 30 and 40 meters and peak transfer rates of 50 kbit/s and 800 kbit/s respectively. In addition, we observed that, in all measurement scenarios, link performance depended strongly on whether bicycles were approaching or moving away, rather than on whether one was at the front or back of the other.
- Influence of Soil Chemistry and Plant Physiology in the Phytoremediation of Cu, Mn, and ZnPublication . Pinto, Edgar; Aguiar, Ana; Ferreira, IsabelDifferent anthropogenic sources of metals can result from agricultural, industrial, military, mining and urban activities that contribute to environmental pollution. Plants can be grown for phytoremediation to remove or stabilize contaminants in water and soil. Copper (Cu), manganese (Mn) and zinc (Zn) are trace essential metals for plants, although their role in homeostasis in plants must be strictly regulated to avoid toxicity. In this review, we summarize the processes involved in the bioavailability, uptake, transport and storage of Cu, Mn and Zn in plants. The efficiency of phytoremediation depends on several factors including metal bioavailability and plant uptake, translocation and tolerance mechanisms. Soil parameters, such as clay fraction, organic matter content, oxidation state, pH, redox potential, aeration, and the presence of specific organisms, play fundamental roles in the uptake of trace essential metals. Key processes in the metal homeostasis network in plants have been identified. Membrane transporters involved in the acquisition, transport and storage of trace essential metals are reviewed. Recent advances in understanding the biochemical and molecular mechanisms of Cu, Mn and Zn hyperaccumulation are described. The use of plant-bacteria associations, plant-fungi associations and genetic engineering has opened a new range of opportunities to improve the efficiency of phytoremediation. The main directions for future research are proposed from the investigation of published results.
- MobiWise: Eco-routing decision support leveraging the Internet of thingsPublication . Aguiar, Ana; Fernandes, Paulo; Guerreiro, Andreia; Tomás, Ricardo; Agnelo, João; Santos, José Luís; Araújo, Filipe; Coelho, Margarida C.; Fonseca, Carlos M.; D'Orey, Pedro; Luís, Manuel; Sargento, SusanaEco-routing distributes traffic in cities to improve mobility sustainability. The implementation of eco-routing in real-life requires a diverse set of information, including different kinds of sensors. These sensors are often already integrated in city infrastructure, some are technologically outdated, and are often operated by multiple entities. In this work, we provide a use case-oriented system design for an eco-routing service leveraging Internet-of-Things (IoT) technologies. The methodology involves six phases: 1) defining an eco-routing use case for a vehicle fleet; 2) formulating a routing problem as a multi-objective optimisation to divert traffic at a relevant hub facility; 3) identifying data sources and processing required information; 4) proposing a microservice-based architecture leveraging IoT technologies adequate to a multi-stakeholder scenario; 5) applying a microscopic traffic simulator as a digital twin to deal with data sparsity; and 6) visually illustrating eco-routing trade-offs to support decision making. We built a proof-of-concept for a mid-sized European city. Using real data and a calibrated digital twin, we would achieve hourly total emissions reductions up to 2.1%, when applied in a car fleet composed of 5% of eco-routing vehicles. This traffic diversion would allow annual carbon dioxide and nitrogen oxides savings of 400 tons and 1.2 tons, respectively.