ISEP – CISTER – Pósteres apresentados a eventos científicos
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- Performance analysis of a VLC system applied to a hospital environment for IoT- based smart patient monitoringPublication . Fernández, Benjamín; Játiva, Pablo Palacios; Azurdia Meza, Cesar A.; Boettcher, Nicolás; Zabala Blanco, David; Gutiérrez Gaitán, Miguel; Soto, IsmaelThis article discusses the deployment of effective communication networks for smart IoT-based smart patient monitoring in medical facilities, advocating for the adoption of Visible Light Communication (VLC) technology. Initially, the physical scenario is analyzed, taking into account factors such as line-of-sight (LOS) and nonline-of-sight (NLOS) channel components. Furthermore, a transmitter is designed to offer a substitute in the event of potential disruptions due to patient motion or loss of line-of-sight elements. The performance of the proposed system is verified under certain performance metrics, such as the Channel Impulse Response (CIR) and the Cumulative Distribution Function (CDF), with respect to power measurements at different points. The results highlight the effects that NLOS rays have on the received data and the received power. Therefore, this study serves as a step towards the development of more sophisticated systems for patient monitoring using enabling technologies such as VLC.
- NB-IoT path loss experimental measurements in urban outdoor environmentsPublication . Moreno, Martín; Oxman, Daniela; Sandoval, Jorge; Meza, Cesar A. Azurdia; Gutiérrez Gaitán, Miguel; Játiva, Pablo Palacios; Firoozabad, Ali DehghanThis paper presents a performance analysis of the Narrowband Internet of Things (NB-IoT) network coverage in urban outdoor environments, focusing on experimental measurements toward path loss modeling. Conducted in a major Latin American city, the study explores the deployment of NB-IoT in LTE guardband 28 (700 MHz), offering valuable information on the network characteristics and coverage performance within this narrow spectrum. Four path loss models are considered, including comparisons between alpha-beta-gamma (ABG) and close-in (CI) empirical models. The end goal is to provide practical tools to optimize the deployment of the NB-IoT network in various urban environments. The results obtained offer a fresh perspective on the importance of experimental validation to accurately predict NB-IoT network coverage and signal quality in a real-world setting. Notably, the work has been carried out in collaboration with a Chilean telecom operator.
- Improved memory contention analysis for the 3-Phase task modelPublication . Arora, Jatin; Rashid, Syed Aftab; Nelissen, Geoffrey; Maia, Cláudio; Tovar, EduardoIn multiprocessor-based real-time systems, main memory is identified as a major bottleneck in the worst-case timing analysis of tasks. Phased execution models such as the 3-phase task model, i.e., that divides the execution of tasks into distinct computation and memory phases, have shown to be a good candidate to tackle the memory contention problem. The 3-phase execution model in particular has gained much attention from both academia and industry as it limits when tasks can access main memory to pre-defined phases. Information on when those phases may happen and their length can then be leveraged to build a fine-grained memory contention analysis. However, the existing work that focus on the memory contention analysis for 3-phase tasks may overestimate the memory contention caused by interfering write requests. This yields pessimistic bounds on the total memory contention suffered by tasks which in turn leads to pessimistic worst-case execution time (WCET) and worst-case response time (WCRT) bounds. In this work, we improve the state-of-the-art memory contention analysis for 3-phase tasks by (i) tightly bounding the memory contention that can be suffered due to write requests; and (ii) providing a new memory contention-aware WCET analysis.
- Complex Intersections with a Dedicated Road Lane per Crossing DirectionPublication . Reddy, Radha; Almeida, Luis; Santos, Pedro M.; Tovar, EduardoComplex intersections are often busier with a separate road lane per crossing direction, i.e., left, straight, and right. These intersections eliminate the diverging and merging conflicts; thus, vehicles only fall under crossing conflicts within intersections. However, the traditional way of serving vehicles from one road at a time increases traffic congestion and hinders performance. To address this issue, we extended the synchronous framework for complex intersections with a separate road lane per crossing direction, which was initially presented for single-lane and two-lane intersections in which roads are shared among vehicles with different crossing directions. We compare the performance of our synchronous framework against the traditional Round-Robin (RR) intersection management approach.
- An Experimental Localization Testbed based on UWB Channel Impulse Response MeasurementsPublication . Li, Kai; Ni, Wei; Zhang, PeiIn this paper, we demonstrate a new ultra-wideband (UWB) localization testbed, which tracks a UWB tag and estimates locations of obstacles based on channel impulse response measurements. Anchor nodes that are developed with off-the-shelf Decawave DW1000 UWB transceivers are deployed to cover the area of interest. The testbed is implemented and preliminary experiments are carried out to estimate the location of the object by analyzing channel impulse response strength of the UWB tag.
- Improving WiFi communication with surface nodes at near-shore on tidal watersPublication . Gutiérrez Gaitán, Miguel; d'Orey, Pedro; Santos, Pedro Miguel; Ribeiro, Manuel; Pinto, Luis; Almeida, Luís; de Sousa, J. BorgesWireless radio links deployed in aquatic areas (e.g., sea, rivers, lakes, estuaries) are affected by the conductive properties of the water surface, strengthening signal reflections and increasing destructive interference. Recurrent natural phenomena (e.g. tides or waves) cause shifts in water levels further impairing propagation over water surfaces. In this work, we aim to mitigate the detrimental impact of tides on link quality by providing tailored link distance/height-design regions that minimize average path losses. We focus on line-of-sight (LOS) over-water links between onshore stations and different types of surface nodes, namely AUVs, buoys, or USVs, using 2.4 GHz and 5 GHz frequency bands. Analytical results targeting mission data transfer scenarios demonstrate that the proposed method outperforms, in both frequency bands, the common practice of placing (i) onshore antennas at the largest possible height and/or (ii) surface nodes at a short but arbitrary distance from the shore. A longer version of this summary was presented at IEEE/MTS OCEANS 2021.
- Poster Abstract: Multi-Drone Assisted Internet of Things Testbed Based on Bluetooth 5 CommunicationsPublication . Li, Kai; Lu, Ning; Zhang, Pei; Ni, Wei; Tovar, EduardoIn this paper, a multi-hop airborne system is built based on Bluetooth 5 connected autonomous drones to relay real-time data of Internet of Things (IoT). A new lightweight Onboard Bluetooth Transceiver (OBT) is developed for reliable drone-to-drone and drone-to-ground communications. A graphical user interface is presented to monitor real-time flight trajectory of the drones and end-to-end data delivery. Outdoor experiments are conducted in real world to test autonomous flight control of the drones and received signal strength of the OBT communications.
- Wi-Fi-based network systems design over freshwater: Experimental evaluation using COTS devicesPublication . Gutiérrez Gaitán, Miguel; Santos, Pedro Miguel; Pinto, Luis; Almeida, LuísTo experimentally assess the impact of surface reflection on the received signal strength of a set of short-andmedium-range shore-to-shore links (<200 m) that use antennas installed at two heights, at a few meters above surface (<3 m).
- Development of the trajectory planner and control system of a spherical robot manipulator embedded in a FPGA boardPublication . Filho, Ênio; Llanos Quintero, C H; Carvalho, G C deThis work describes the development and implementation of a linear trajectory controller in a five degree of freedom (DOF) robot manipulator (Filho and Quintero 2013). An open loop control architecture was designed and embedded in a Field Programable Gate Array (FPGA), for the first threeDOF. In this paper, we present the direct and inverse kinematics and the Jacobian of the manipulator, used to extract the control equations of the system (Motta, Llanos-Quintero, and Coral Sampaio 2016). This model aims the trajectory planning in a rectilinear path, described in Cartesian Coordinates. For the control implementation embedded in the FPGA, was used the NIOS II microprocessor. This one is responsible for the path planning and for the speed control of the manipulator joints, with some accelerated functions in hardware. The validation of the equations and path planning were done using software simulation. The final structure and experiments of the manipulator are also presented.
- Low Cost IOT system for Residential Automation using Open Hardware and Open Software with a Focus on DisabilitiesPublication . Prado, Felipe Oliveira; Silva Neto, Joiro Gomes da; Filho, ÊnioThe quest for comfort and practicality is commonplace in contemporary society, but such benefits are still not offered satisfactorily to all. Among these, special attention is given to people with Disabilities, who often do not enjoy the latest technologies in applications and automated systems because they do not have their needs covered by these technologies (Domingo 2012). The aim of this work was to develop an automation system that would increase the level of inclusion. Tis work also propose a low cost residential automated system, developed using electronic waste, open hardware and open software, to increase the application of the system. There were used platforms of easy access, and easy replication, aiming at the dissemination of technology (Trihinas, Pallis, and Dikaiakos 2018). Among these platforms, it is possible to highlight the Google Assistant (Chatterjee, n.d.). All the platforms used helps the development of an Internet of Things (IOT) system, with multiple capabilities. Finally, functional tests were performed of three physical modules to control a door, a set of sockets and some lamps, using RFID, cellular and voice cards for its activation.