scholarly journals A Protocol for Aerial Survey in Coastal Areas Using UAS

2019 ◽  
Vol 11 (16) ◽  
pp. 1913 ◽  
Author(s):  
Michaela Doukari ◽  
Marios Batsaris ◽  
Apostolos Papakonstantinou ◽  
Konstantinos Topouzelis

Aerial surveys in coastal areas using Unmanned Aerial Vehicles (UAVs) present many limitations. However, the need for detailed and accurate information in a marine environment has made UAVs very popular. The aim of this paper is to present a protocol which summarizes the parameters that affect the reliability of the data acquisition process over the marine environment using Unmanned Aerial Systems (UAS). The proposed UAS Data Acquisition Protocol consists of three main categories: (i) Morphology of the study area, (ii) Environmental conditions, (iii) Flight parameters. These categories include the parameters prevailing in the study area during a UAV mission and affect the quality of marine data. Furthermore, a UAS toolbox, which combines forecast weather data values with predefined thresholds and calculates the optimal flight window times in a day, was developed. The UAS toolbox was tested in two case studies with data acquisition over a coastal study area. The first UAS survey was operated under optimal conditions while the second was realized under non-optimal conditions. The acquired images and the produced orthophoto maps from both surveys present significant differences in quality. Moreover, a comparison between the classified maps of the case studies showed the underestimation of some habitats in the area at the non-optimal survey day. The UAS toolbox is expected to contribute to proper flight planning in marine applications. The UAS protocol can provide valuable information for mapping, monitoring, and management of the coastal and marine environment, which can be used globally in research and a variety of marine applications.

Drones ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 73
Author(s):  
Michaela Doukari ◽  
Marios Batsaris ◽  
Konstantinos Topouzelis

Unmanned aerial systems (UAS) are widely used in the acquisition of high-resolution information in the marine environment. Although the potential applications of UAS in marine habitat mapping are constantly increasing, many limitations need to be overcome—most of which are related to the prevalent environmental conditions—to reach efficient UAS surveys. The knowledge of the UAS limitations in marine data acquisition and the examination of the optimal flight conditions led to the development of the UASea toolbox. This study presents the UASea, a data acquisition toolbox that is developed for efficient UAS surveys in the marine environment. The UASea uses weather forecast data (i.e., wind speed, cloud cover, precipitation probability, etc.) and adaptive thresholds in a ruleset that calculates the optimal flight times in a day for the acquisition of reliable marine imagery using UAS in a given day. The toolbox provides hourly positive and negative suggestions, based on optimal or non-optimal survey conditions in a day, calculated according to the ruleset calculations. We acquired UAS images in optimal and non-optimal conditions and estimated their quality using an image quality equation. The image quality estimates are based on the criteria of sunglint presence, sea surface texture, water turbidity, and image naturalness. The overall image quality estimates were highly correlated with the suggestions of the toolbox, with a correlation coefficient of −0.84. The validation showed that 40% of the toolbox suggestions were a positive match to the images with higher quality. Therefore, we propose the optimal flight times to acquire reliable and accurate UAS imagery in the coastal environment through the UASea. The UASea contributes to proper flight planning and efficient UAS surveys by providing valuable information for mapping, monitoring, and management of the marine environment, which can be used globally in research and marine applications.


Heritage ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 1404-1422 ◽  
Author(s):  
Apostolos Papakonstantinou ◽  
Dimitris Kavroudakis ◽  
Yannis Kourtzellis ◽  
Michail Chtenellis ◽  
Vasilis Kopsachilis ◽  
...  

Dynamic processes in coastal zones and human activities in the coastal environment produce pressure on cultural heritage, especially in touristic places. Unmanned aerial systems (UAS) are used as an additional tool for monitoring cultural heritage sites in sensitive coastal areas. UASs provide low-cost accurate spatial data and high-resolution imagery products in various spatial and temporal scales. The use of UAS for mapping cultural heritage sites in the coastal zone is of increasing interest among scientists and archaeologists in terms of monitoring, documentation, mapping, and restoration. This study outlines the integration of UAS data acquisition and structure from motion (SfM) pipeline for the visualization of selected cultural heritage areas (ancient harbors) in the coastal zone. The UAS-SfM methodology produces very detailed orthophoto maps for mapping and detecting cultural heritage sites. Additionally, a metadata cataloging system has been developed in order to facilitate online searching operations for all products of the data acquisition, SfM pipeline, and cartographic processes. For this reason, a specific metadata profile was implemented, based on the European INSPIRE framework. As a result, datasets reusability and catalogs interoperability are promoted.


Explanations are very important to us in many contexts: in science, mathematics, philosophy, and also in everyday and juridical contexts. But what is an explanation? In the philosophical study of explanation, there is long-standing, influential tradition that links explanation intimately to causation: we often explain by providing accurate information about the causes of the phenomenon to be explained. Such causal accounts have been the received view of the nature of explanation, particularly in philosophy of science, since the 1980s. However, philosophers have recently begun to break with this causal tradition by shifting their focus to kinds of explanation that do not turn on causal information. The increasing recognition of the importance of such non-causal explanations in the sciences and elsewhere raises pressing questions for philosophers of explanation. What is the nature of non-causal explanations—and which theory best captures it? How do non-causal explanations relate to causal ones? How are non-causal explanations in the sciences related to those in mathematics and metaphysics? This volume of new essays explores answers to these and other questions at the heart of contemporary philosophy of explanation. The essays address these questions from a variety of perspectives, including general accounts of non-causal and causal explanations, as well as a wide range of detailed case studies of non-causal explanations from the sciences, mathematics and metaphysics.


2013 ◽  
Vol 224 (7) ◽  
Author(s):  
Håkan Pleijel ◽  
Jenny Klingberg ◽  
Gunilla Pihl Karlsson ◽  
Magnuz Engardt ◽  
Per Erik Karlsson

2021 ◽  
Author(s):  
Pablo Lorente ◽  

<p>The Mediterranean Sea is considered a relevant geostrategic region and a prominent climate change hot spot. This semi-enclosed basin has been the subject of abundant studies due to its vulnerability to sea-level rise and other coastal hazards. With the steady advent of new technologies, a growing wealth of observational data are nowadays available to efficiently monitor the sea state and properly respond to socio-ecological challenges and stakeholder needs, thereby strengthening the community resilience at multiple scales.</p><p>Nowadays, High-Frequency radar (HFR) is a worldwide consolidated land-based remote sensing technology since it provides, concurrently and in near real time, fine-resolution maps of the surface circulation along with (increasingly) wave and wind information over broad coastal areas. HFR systems present a wide range of practical applications: maritime safety, oil spill emergencies, energy production, management of extreme coastal hazards. Consequently, they have become an essential component of coastal ocean observatories since they offer a unique dynamical framework that complement conventional in-situ observing platforms. Likewise, within the frame of the Copernicus Marine Environment Monitoring Service (CMEMS), HFR are valuable assets that play a key pivotal role in both the effective monitoring of coastal areas and the rigorous skill assessment of operational ocean forecasting systems.</p><p>The present work aims to show a panoramic overview not only of the current status of diverse Mediterranean HFR systems, but also of the coordinated joint efforts between many multi-disciplinary institutions to establish a permanent HFR monitoring network in the Mediterranean, aligned with European and global initiatives. In this context, it is worth highlighting that many of the Mediterranean HFR systems are already integrated into the European HFR Node, which acts as central focal point for data collection, homogenization, quality assurance and dissemination and promotes networking between EU infrastructures and the Global HFR network.</p><p>Furthermore, priority challenges tied to the implementation of a long-term, fully integrated, sustainable operational Mediterranean HFR network are described. This includes aspects related to the setting up of such a system within the broader framework of the European Ocean Observing System (EOOS), and a long-term financial support required to preserve the infrastructure core service already implemented. Apart from the technological challenges, the enhancing of the HFR data discovery and access, the boosting of the data usage as well as the research integration must be achieved by building synergies among academia, management agencies, state government offices, intermediate and end users. This would guarantee a coordinated development of tailored products that meet the societal needs and foster user uptake, serving the marine industry with dedicated smart innovative services, along with the promotion of strategic planning and informed decision-making in the marine environment.</p>


2020 ◽  
pp. 446-464
Author(s):  
Suhaila Ismail ◽  
Elena Sitnikova ◽  
Jill Slay

Past cyber-attacks on Supervisory Control and Data Acquisition (SCADA) Systems for Critical infrastructures have left these systems compromised and caused financial and economic problems. Deliberate attacks have resulted in denial of services and physical injury to the public in certain cases. This study explores the past attacks on SCADA Systems by examining nine case studies across multiple utility sectors including transport, energy and water and sewage sector. These case studies will be further analysed according to the cyber-terrorist decision-making theories including strategic, organisational and psychological theories based on McCormick (2000). Next, this study will look into cyber-terrorist capabilities in conducting attacks according to Nelson's (1999) approach that includes simple-unstructured, advance-structured and complex-coordinated capabilities. The results of this study will form the basis of a guideline that organisations can use so that they are better prepared in identifying potential future cybersecurity attacks on their SCADA systems.


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