Search results for "feature"

Dynamics of outgassing and plume transport revealed by proximal Unmanned Aerial System (UAS) measurements at Volcán Villarrica, Chile

2019

Volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing, and, on geological timescales, constitute an important source of volatiles to the Earth's atmosphere. Measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles. However, significant gaps remain in our global inventories of volcanic emissions, (particularly for CO2, which requires proximal sampling of a concentrated plume) for those volcanoes where the near‐vent region is hazardous or inaccessible. Unmanned Aerial Systems (UAS) provide a robust and effective solution to proximal sampling of …

A facies distribution model controlled by a tectonically inherited sea bottom topography in the carbonate rimmed shelf of the Upper Tithonian–Valangi…

2016

The Upper Tithonian–Valanginian shallow-water carbonates outcropping in the Palermo Mts (NW Sicily) consist of several facies associations reflecting different depositional environments of a carbonate rimmed shelf, pertaining to the Southern Tethyan continental margin. The reconstructed depositional model, based on the sedimentological features, cyclic facies arrangement and biota distribution, shows that a wide protected lagoon, dominated by algae, molluscs and scattered patch reefs, was bordered landward by a tidal flat, where stromatolitic algal mats were cyclically subaerial exposed, and seaward by a marine sand belt and reef complex. Oolitic packstone-grainstone lithofacies, cyclically…

Monthly Hydrological Indicators to Assess Possible Alterations on Rivers’ Flow Regime

2018

Assessing potential deviations of the fundamental river basins’ hydrological processes and streamflow characteristics from the “natural trajectory” represents a high-priority objective to understand the biological impact of altered flow regime on river ecosystems. Existing approaches are mainly based on the analysis of daily-based indicators of hydrologic alteration, which requires wide database, including “pre-impact” and “post-impact” daily flow data frequently unavailable. The hydrological modeling is commonly used to face data missing problems or reconstruct natural conditions, even if models, especially at the daily scales, are often complex and computationally intensive. The use of si…

Trans-boundary land cover changes and its influences on water crisis: Case study of the Aras River

2020

Abstract In a watershed, disturbing land covers (LCs) are one of the most important factors in the balance and flow rate of water. This study aimed to monitor and model LC changes in the upstream of the Aras River Basin in Turkey over 1984, 2002, 2010 and 2016. The main ground to conduct such an analysis was to mitigate severe economic, social and ecological consequences driven by agricultural activities and dam construction along with probable climate change, which would decrease the water flow from the Aras River to Caspian Sea. The study approach consisted of four main steps: 1) producing LC maps using Landsat satellite images, 2) performing the change analysis, 3) identifying the change…

2021

In COVID-19 related infodemic, social media becomes a medium for wrongdoers to spread rumors, fake news, hoaxes, conspiracies, astroturf memes, clickbait, satire, smear campaigns, and other forms of deception. It puts a tremendous strain on society by damaging reputation, public trust, freedom of expression, journalism, justice, truth, and democracy. Therefore, it is of paramount importance to detect and contain unreliable information. Multiple techniques have been proposed to detect fake news propagation in tweets based on tweets content, propagation on the network of users, and the profile of the news generators. Generating human-like content allows deceiving content-based methods. Networ…

Extracting Features from Social Media Networks Using Semantics

2016

This paper focuses on the analysis of social media content generated by social networks (e.g. Twitter) in order to extract semantic features. By using text categorization to sort text feeds into categories of similar feeds, it has been proved to reduce the overhead that is required to retrieve these feeds and at the same time, it provides smaller pools in which further investigations can be made easier. The aim of this survey is to draw a user profile, by analysing his or her tweets. In this early stage of research, being a pre-processing phase, a dictionary based approach is considered. Moreover, the paper describes an algorithm used in analysing the text and its preliminary results. This …

Individual habitat transitions of Atlantic herring Clupea harengus in a human-modified coastal system

2015

Published version of an article from the journal: Marine Ecology Progress Series. Also available from Inter Research. Http://dx.doi.org/10.3354/meps11103 Pelagic marine fish often display highly dynamic migration patterns. However, such movement behaviour is usually studied at the population or school level, while less is known about individual movement characteristics and habitat transitions. During March 2012 to June 2013, we used acoustic tags and moored receivers to monitor the behaviour of Atlantic herring Clupea harengus L. (N = 47) throughout a range of habitats on the Skagerrak coast in southern Norway. Five of the tagged herring entered a former lake transformed into an artificial …

An Algorithm for Discretization of Real Value Attributes Based on Interval Similarity

2013

Discretization algorithm for real value attributes is of very important uses in many areas such as intelligence and machine learning. The algorithms related to Chi2 algorithm (includes modified Chi2 algorithm and extended Chi2 algorithm) are famous discretization algorithm exploiting the technique of probability and statistics. In this paper the algorithms are analyzed, and their drawback is pointed. Based on the analysis a new modified algorithm based on interval similarity is proposed. The new algorithm defines an interval similarity function which is regarded as a new merging standard in the process of discretization. At the same time, two important parameters (condition parameterαand ti…

The impact of COVID ‐19 on franchising in emerging markets: An example from Brazil

2020

The outbreak of COVID‐19, the disease caused by the SARS‐CoV‐2 virus, has had significant economic, political, and social consequences worldwide. The franchising sector, consisting mostly of retail and service businesses, is an example of an industry that has been deeply affected. The experiences of franchising stakeholders in Brazil highlight the strengths of the franchising model in such situations. This investigation, based on primary data from webinars with food service, education, retail, and business‐to‐business service companies in Brazil, coupled with reports from commercial and franchising entities, reveals how the COVID‐19 outbreak has affected the franchising sector. It illustrat…

Automatic Relative Radiometric Normalization of Bi-Temporal Satellite Images Using a Coarse-to-Fine Pseudo-Invariant Features Selection and Fuzzy Int…

2022

Relative radiometric normalization (RRN) is important for pre-processing and analyzing multitemporal remote sensing (RS) images. Multitemporal RS images usually include different land use/land cover (LULC) types; therefore, considering an identical linear relationship during RRN modeling may result in potential errors in the RRN results. To resolve this issue, we proposed a new automatic RRN technique that efficiently selects the clustered pseudo-invariant features (PIFs) through a coarse-to-fine strategy and uses them in a fusion-based RRN modeling approach. In the coarse stage, an efficient difference index was first generated from the down-sampled reference and target images by combining…