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11 pages, 8050 KiB

Open AccessCommunication

An Igor Pro 8.01 Procedure to Analyze Pulse Oximetry during Acute Hypoxia Test in Aircrews

by Manuel Alvear-Catalán, Claudio Montiglio, Ignacio Perales, Ginés Viscor and Oscar F. Araneda

Sensors 2023, 23(4), 2327; https://doi.org/10.3390/s23042327 - 20 Feb 2023

Viewed by 1555

The recognition of hypoxia symptoms is a critical part of physiological training in military aviation. Acute exposure protocols have been designed in hypobaric chambers to train aircrews to recognize hypoxia and quickly take corrective actions. The goal of the acute hypoxia test is [...] Read more.

The recognition of hypoxia symptoms is a critical part of physiological training in military aviation. Acute exposure protocols have been designed in hypobaric chambers to train aircrews to recognize hypoxia and quickly take corrective actions. The goal of the acute hypoxia test is to know the time of useful consciousness and the minimal arterial oxygen saturation tolerated. Currently, there is no computer system specifically designed to analyze the physiological variables obtained during the test. This paper reports the development and analytical capabilities of a computational tool specially designed for these purposes. The procedure was designed using the Igor Pro 8.01 language, which processes oxygen saturation and heart rate signals. To accomplish this, three functional boards are displayed. The first allows the loading and processing of the data. The second generates graphs that allow for a rapid visual examination to determine the validity of individual records and calculate slopes on selected segments of the recorded signal. Finally, the third can apply filters to generate data groups for analysis. In addition, this tool makes it possible to propose new study variables that are derived from the raw signals and can be applied simultaneously to large data sets. The program can generate graphs accompanied by basic statistical parameters and heat maps that facilitate data visualization. Moreover, there is a possibility of adding other signals during the test, such as the oxygenation level in vital organs, electrocardiogram, or electroencephalogram, which illustrates the test’s excellent potential for application in aerospace medicine and for helping us develop a better understanding of complex physiological phenomena. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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24 pages, 3886 KiB

Open AccessArticle

Three Shaft Industrial Gas Turbine Transient Performance Analysis

by Waleligne Molla Salilew, Zainal Ambri Abdul Karim, Tamiru Alemu Lemma, Amare Desalegn Fentaye and Konstantinos G. Kyprianidis

Sensors 2023, 23(4), 1767; https://doi.org/10.3390/s23041767 - 04 Feb 2023

Cited by 3 | Viewed by 1960

Abstract

The power demand from gas turbines in electrical grids is becoming more dynamic due to the rising demand for power generation from renewable energy sources. Therefore, including the transient data in the fault diagnostic process is important when the steady-state data are limited [...] Read more.

The power demand from gas turbines in electrical grids is becoming more dynamic due to the rising demand for power generation from renewable energy sources. Therefore, including the transient data in the fault diagnostic process is important when the steady-state data are limited and if some component faults are more observable in the transient condition than in the steady-state condition. This study analyses the transient behaviour of a three-shaft industrial gas turbine engine in clean and degraded conditions with consideration of the secondary air system and variable inlet guide vane effects. Different gas path faults are simulated to demonstrate how magnified the transient measurement deviations are compared with the steady-state measurement deviations. The results show that some of the key measurement deviations are considerably higher in the transient mode than in the steady state. This confirms the importance of considering transient measurements for early fault detection and more accurate diagnostic solutions. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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12 pages, 4319 KiB

Open AccessArticle

Robust Wheel Detection for Vehicle Re-Identification

by Sally Ghanem and Ryan A. Kerekes

Sensors 2023, 23(1), 393; https://doi.org/10.3390/s23010393 - 30 Dec 2022

Viewed by 2172

Abstract

Vehicle re-identification is a demanding and challenging task in automated surveillance systems. The goal of vehicle re-identification is to associate images of the same vehicle to identify re-occurrences of the same vehicle. Robust re-identification of individual vehicles requires reliable and discriminative features extracted [...] Read more.

Vehicle re-identification is a demanding and challenging task in automated surveillance systems. The goal of vehicle re-identification is to associate images of the same vehicle to identify re-occurrences of the same vehicle. Robust re-identification of individual vehicles requires reliable and discriminative features extracted from specific parts of the vehicle. In this work, we construct an efficient and robust wheel detector that precisely locates and selects vehicular wheels from vehicle images. The associated hubcap geometry can hence be utilized to extract fundamental signatures from vehicle images and exploit them for vehicle re-identification. Wheels pattern information can yield additional information about vehicles in questions. To that end, we utilized a vehicle imagery dataset that has thousands of side-view vehicle collected under different illumination conditions and elevation angles. The collected dataset was used for training and testing the wheel detector. Experiments show that our approach could detect vehicular wheels accurately for 99.41% of the vehicles in the dataset. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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24 pages, 9398 KiB

Open AccessArticle

Evaluation of Doppler Effect Error Affecting the Radio Altimeter Altitude Measurements

by Marek Češkovič, Pavol Kurdel, Natália Gecejová, Ján Labun and Miroslav Laššák

Sensors 2023, 23(1), 177; https://doi.org/10.3390/s23010177 - 24 Dec 2022

Cited by 1 | Viewed by 1966

Abstract

The measurement of the real altitude of aircraft is usually done using an aviation radio altimeter (ALT). A radio altimeter provides crucial information about the instantaneous (radio) altitude of aircraft, helicopter, or unmanned aerial vehicle, to the pilot or another assistance system, such [...] Read more.

The measurement of the real altitude of aircraft is usually done using an aviation radio altimeter (ALT). A radio altimeter provides crucial information about the instantaneous (radio) altitude of aircraft, helicopter, or unmanned aerial vehicle, to the pilot or another assistance system, such as an autopilot or an anti-collision system. However, this flight altitude measurement is affected by several errors, methodological errors and the operating frequency and modulation parameters instability, or the Doppler shift error. This article is focused on the evaluation of how the Doppler effect error develops during the operation of an ALT and its potential use as an information carrier concerning a possible loss of radio altitude, leading to dangerous situations. This paper briefly explains in a theoretical and practical way how this error develops and how it can affect the process of creation of height impulses. Practical experiments were conducted and evaluated in this research, and a theoretical design of a simple circuit capable of signalization of radio altitude loss presented. As the Doppler shift error was previously recognized solely as a measurement error, it could be used in a new function as a source of supplemental warning information. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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13 pages, 2276 KiB

Open AccessArticle

Performance of the SABAT Neutron-Based Explosives Detector Integrated with an Unmanned Ground Vehicle: A Simulation Study

by Michał Silarski and Marek Nowakowski

Sensors 2022, 22(24), 9996; https://doi.org/10.3390/s22249996 - 19 Dec 2022

Cited by 5 | Viewed by 2113

Abstract

The effective and safe detection of illicit materials, explosives in particular, is currently of growing importance taking into account the geopolitical situation and increasing risk of a terrorist attack. The commonly used methods of detection are based predominantly on metal detectors and georadars, [...] Read more.

The effective and safe detection of illicit materials, explosives in particular, is currently of growing importance taking into account the geopolitical situation and increasing risk of a terrorist attack. The commonly used methods of detection are based predominantly on metal detectors and georadars, which show only the shapes of the possible dangerous objects and do not allow for exact identification and risk assessment. A supplementary or even alternative method may be based on neutron activation analysis, which provides the possibility of a stoichiometric analysis of the suspected object and its non-invasive identification. One such sensor is developed by the SABAT collaboration, with its primary application being underwater threat detection. In this article, we present performance studies of this sensor, integrated with a mobile robot, in terms of the minimal detectable quantity of commonly used explosives in different environmental conditions. The paper describes the functionality of the used platform considering electronics, sensors, onboard computing power, and communication system to carry out manual operation and remote control. Robotics solutions based on modularized structures allow the extension of sensors and effectors that can significantly improve the safety of personnel as well as work efficiency, productivity, and flexibility. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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14 pages, 5845 KiB

Open AccessArticle

Ship Berthing and Unberthing Monitoring System in the Ferry Terminal

by Teresa Abramowicz-Gerigk and Jacek Jachowski

Sensors 2022, 22(23), 9133; https://doi.org/10.3390/s22239133 - 24 Nov 2022

Cited by 2 | Viewed by 1482

Abstract

This paper presents a monitoring system designed to increase the safety of the quay structure in ferry terminals, in which, during berthing and unberthing maneuvers, propeller and thruster-generated jets may damage the seabed protection, threatening the stability of the berth structure. Direct measurement [...] Read more.

This paper presents a monitoring system designed to increase the safety of the quay structure in ferry terminals, in which, during berthing and unberthing maneuvers, propeller and thruster-generated jets may damage the seabed protection, threatening the stability of the berth structure. Direct measurement of flow velocity on the seabed is not possible due to the possibility of its damage, therefore dynamic pressure measurement of the quay wall was used within the system. The relationship between the pressure on the quay wall and flow velocity on the seabed was determined using real-scale CFD simulation of the flow field generated during berthing and unberthing maneuvers. The paper focuses on the computations of the pressure distribution generated by bow thrusters. These computations made it possible to determine the velocity field in the time domain. Their results, verified using real-scale measurements, are in line with generally accepted empirical methods. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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16 pages, 7596 KiB

Open AccessArticle

Oriented Vehicle Detection in Aerial Images Based on YOLOv4

by Tai-Hung Lin and Chih-Wen Su

Sensors 2022, 22(21), 8394; https://doi.org/10.3390/s22218394 - 01 Nov 2022

Cited by 5 | Viewed by 1892

Abstract

CNN-based object detectors have achieved great success in recent years. The available detectors adopted horizontal bounding boxes to locate various objects. However, in some unique scenarios, objects such as buildings and vehicles in aerial images may be densely arranged and have apparent orientations. [...] Read more.

CNN-based object detectors have achieved great success in recent years. The available detectors adopted horizontal bounding boxes to locate various objects. However, in some unique scenarios, objects such as buildings and vehicles in aerial images may be densely arranged and have apparent orientations. Therefore, some approaches extend the horizontal bounding box to the oriented bounding box to better extract objects, usually carried out by directly regressing the angle or corners. However, this suffers from the discontinuous boundary problem caused by angular periodicity or corner order. In this paper, we propose a simple but efficient oriented object detector based on YOLOv4 architecture. We regress the offset of an object’s front point instead of its angle or corners to avoid the above mentioned problems. In addition, we introduce the intersection over union (IoU) correction factor to make the training process more stable. The experimental results on two public datasets, DOTA and HRSC2016, demonstrate that the proposed method significantly outperforms other methods in terms of detection speed while maintaining high accuracy. In DOTA, our proposed method achieved the highest mAP for the classes with prominent front-side appearances, such as small vehicles, large vehicles, and ships. The highly efficient architecture of YOLOv4 increases more than 25% detection speed compared to the other approaches. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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20 pages, 4738 KiB

Open AccessArticle

Electrical Disturbances in Terms of Methods to Reduce False Activation of Aerial Fire Protection Systems

by Andrzej Żyluk, Mariusz Zieja, Andrzej Szelmanowski, Justyna Tomaszewska, Magdalena Perlińska and Krzysztof Głyda

Sensors 2022, 22(20), 8059; https://doi.org/10.3390/s22208059 - 21 Oct 2022

Cited by 2 | Viewed by 1558

Abstract

The paper presents an analysis of false triggers of fire protection systems installed on aircraft. They not only cause task interruption but also have a direct impact on flight safety, forcing the crew to land in a risky area. Simulation models of electronic [...] Read more.

The paper presents an analysis of false triggers of fire protection systems installed on aircraft. They not only cause task interruption but also have a direct impact on flight safety, forcing the crew to land in a risky area. Simulation models of electronic actuators were developed to determine the conditions under which false alarms occur. Testing of the simulation models was carried out in the computational package Matlab-Simulink and Circum-Maker for different electrical disturbance generation conditions. The simulation of overvoltage, voltage drops and voltage decays in the on-board electrical network supplying the fire protection system, occurring during the start-up of aircraft engines and during the switching on and off of on-board high-power devices, was studied. The conducted studies have practical applications since the simulation results are an important element for planning experimental tests of the SSP-FK-BI executive blocks under electrical disturbance conditions. Based on the simulation and experimental studies, the conditions causing false tripping of the fire protection system and the parameters for selected disturbance factors have been determined. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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20 pages, 2624 KiB

Open AccessArticle

Potential Benefit of Structural Health Monitoring System on Civil Jet Aircraft

by Vincenzo Cusati, Salvatore Corcione and Vittorio Memmolo

Sensors 2022, 22(19), 7316; https://doi.org/10.3390/s22197316 - 27 Sep 2022

Cited by 6 | Viewed by 6731

Abstract

Structural health monitoring represents an interesting enabling technology towards increasing aviation safety and reducing operating costs by unlocking novel maintenance approaches and procedures. However, the benefits of such a technology are limited to maintenance costs reductions by cutting or even eliminating some maintenance [...] Read more.

Structural health monitoring represents an interesting enabling technology towards increasing aviation safety and reducing operating costs by unlocking novel maintenance approaches and procedures. However, the benefits of such a technology are limited to maintenance costs reductions by cutting or even eliminating some maintenance scheduled checks. The key limitation to move a step further in exploiting structural health monitoring technology is represented by the regulation imposed in sizing aircraft composite structures. A safety margin of 2.0 is usually applied to estimate the ultimate loading that composite structures must withstand. This limitation is imposed since physical nondestructive inspection of composite structures is really challenging or even impossible in some cases. However, a structural health monitoring system represents a viable way for a real time check for the health status of a composite structure. Thus, the introduction of structural health monitoring should help into reducing the stringent safety margin imposed by aviation regulation for a safe design of composite structures. By assuming a safety margin reduction from 2.0 to 1.75 thanks to the installation of permanently attached sensors for structural health diagnostics, this paper assesses the potential fuel savings and direct operating costs through a multidisciplinary analysis on a A220-like aircraft. According to the foreseen level of technology, addressed through the number of sensors per square meter, a DOC saving from 2% up to 5% is achievable preserving, at the same time, all the key aircraft performance. Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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17 pages, 3775 KiB

Open AccessArticle

Announcement Signals and Automatic Braking Using Virtual Balises in Railway Transport Systems

by Enrique Santiso, José A. Jiménez, Manuel Mazo, Cristina Losada and Francisco J. Rodríguez

Sensors 2022, 22(5), 1943; https://doi.org/10.3390/s22051943 - 02 Mar 2022

Viewed by 2288

Abstract

In rail transport, various automatic protection systems are available to ensure the safe operation of trains and to facilitate automation and optimization tasks. For this purpose, a set of physical balises is used, which are placed at fixed points along the railway track. [...] Read more.

In rail transport, various automatic protection systems are available to ensure the safe operation of trains and to facilitate automation and optimization tasks. For this purpose, a set of physical balises is used, which are placed at fixed points along the railway track. Based on the information provided by these balises, different information is displayed to the driver, and control actions are generated. The use of physical balises located at fixed points does not allow for automatic protection actions on sections of track where they are not installed. This is a major drawback as in many cases, temporary automatic protection actions are necessary on sections of the railway line without balises due to various circumstances (work on the track, accidents, etc.). To solve this problem, this paper presents a solution called announcement signals and automatic braking using virtual balises (ASAB-VB). This proposal allows the incorporation of virtual balises at points on the track where it is necessary to temporarily perform automatic protection actions. For this purpose, the ASAB-VB system allows obtaining the train position in real-time and storing a digital map of the track that will be made by each train. This digital map includes geographic information about the balises (both physical and virtual ones) located on the track. At the same time, the train position is obtained by merging the information provided by a GNSS, an odometer, and an inertial system (gyro and accelerometers). Full article

(This article belongs to the Special Issue Monitoring System for Aircraft, Vehicle and Transport Systems)

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