Search results for "Computer network"
showing 10 items of 1634 documents
INTEGRATED SFM TECHNIQUES USING DATA SET FROM GOOGLE EARTH 3D MODEL AND FROM STREET LEVEL
2017
Abstract. Structure from motion (SfM) represents a widespread photogrammetric method that uses the photogrammetric rules to carry out a 3D model from a photo data set collection. Some complex ancient buildings, such as Cathedrals, or Theatres, or Castles, etc. need to implement the data set (realized from street level) with the UAV one in order to have the 3D roof reconstruction. Nevertheless, the use of UAV is strong limited from the government rules. In these last years, Google Earth (GE) has been enriched with the 3D models of the earth sites. For this reason, it seemed convenient to start to test the potentiality offered by GE in order to extract from it a data set that replace the UAV …
A2Ba: Adaptive Background Modelling for Visual Aerial Surveillance Conditions
2015
International audience; Background modelling algorithms are widely used to define a part of an image that most time remains stationary in a video. In surveillance tasks, this model helps to recognize those outlier objects in an area under monitoring. Set up a background model on mobile platforms (UAVs, intelligent cars, etc.) is a challenging task due camera motion when images are acquired. In this paper, we propose A2Ba, a robust method to support instabilities caused by aerial images fusing different information about image motion. We used frame difference as first approximation, then age of pixels is estimated. This latter gives us an invariability level of a pixel over time. Gradient di…
Analysis and Performance Evaluation of the IEEE 802.16 ARQ Mechanism
2008
The IEEE 802.16 standard defines the ARQ mechanismas a part of the MAC layer. The functioning of the ARQmechanism depends on a number of parameters. The IEEE802.16 specification defines them but it does not provide concrete values and solutions. This paper studies the key features and parameters of the 802.16 ARQ mechanism. In particular, we consider a choice for the ARQ feedback type, an algorithm to build block sequences, the ARQ feedback intensity, a scheduling of the ARQ feedbacks and retransmissions, the ARQ block rearrangement, ARQ transmission window and the ARQ block size. We ran simulation scenarios to study these parameters and how they impact the performance of application protoc…
Comparative Analyses between the Zero-Inertia and Fully Dynamic Models of the Shallow Water Equations for Unsteady Overland Flow Propagation
2018
The shallow water equations are a mathematical tool widely applied for the simulation of flow routing in rivers and floodplains, as well as for flood inundation mapping. The interest of many researchers has been focused on the study of simplified forms of the original set of equations. One of the most commonly applied simplifications consists of neglecting the inertial terms. The effects of such a choice on the outputs of the simulations of flooding events are controversial and are an important topic of debate. In the present paper, two numerical models recently proposed for the solution of the complete and zero-inertia forms of the shallow water equations, are applied to several unsteady f…
The environmental information report in the annual accounts: An analysis of the main ports in Spain
2019
The aim of this work is to present the content analysis on the intelligibility of the environmental information that is reported in the annual accounts of the main Port Authorities in Spain. The annual accounts are related to documents that contain primarily financial information, and thus meet the needs of users (especially external users) in the decision-making process; in this sense, the work analyzes the environmental aspects presented in them. The data analyzed lead us to conclude that the Port Authorities of Castellón, Gijón and Valencia are the ones that provide the most information about their activities and environmental actions in their annual reports; however, with regard to the …
Virtual Reality and Games
2018
The concept of Virtual Reality (VR) dates back to around 1930, where different technologies and concepts arise. For instance, in 1929 Edward Link created the Link Trainer (further patented in 1931), reported to be the first example of a commercial flight simulator, being entirely electromechanical. Also, in the 1930s, the visionary, science fiction writer Stanley G. Weinbaum brings a story (Pygmalion’s Spectacles) that introduces the early idea of a pair of goggles that makes the wearer experience a fictional world through holograms, smell, taste, and touch. Weinbaum describes uncanny experiences for those wearing the goggles, aligned with the modern experiences of VR. It is in the mid 1950…
Strategies for Improving Optimal Positioning of Quality Sensors in Urban Drainage Systems for Non-Conservative Contaminants
2021
In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network is necessary to promptly detect and contain the event of contamination. Sensor location is usually an optimization exercise that is based on probabilistic or black-box methods and their efficiency is usually dependent on the initial assumption made on possible eligibility of nodes to become a monitoring point. It is a common practice to establish an initial non-informative assumption by considering all network…
How perceived value drives the use of mobile financial services apps
2019
Mobile information services have revolutionized business models and service delivery methods by facilitating consumer access to information and order placement via mobile apps. In developed markets, mobile banking (m-banking) and mobile payment (m-payment) applications have replaced text-based mobile services. However, extant research has not addressed these mobile financial services apps (MFSAs) adequately from the perspective of consumer behavior. Thus, the present study developed and tested a series of hypotheses related to the antecedents of perceived value of MFSA use; it also examined how such use affects the development of customers’ overall relationships with banks. Our hypotheses w…
Role of situational context in use continuance after critical exergaming incidents
2019
Use continuance is crucial in terms of information systems (IS) success. Previous research has shown that situational context can be central for IS use continuance but has paid limited attention to its specific characteristics. Furthermore, the link between situational context and use continuance has remained unexplored in the novel area of “exergames,” which are defined as digital games requiring physical effort from the player that determines the outcome of the game. Studying exergames is deemed important due to their potential in providing health benefits for users, revenues for providers, and well‐being for societies. However, their potential remains unreached because users tend to disc…
Altered EEG Oscillatory Brain Networks During Music-Listening in Major Depression
2021
To examine the electrophysiological underpinnings of the functional networks involved in music listening, previous approaches based on spatial independent component analysis (ICA) have recently been used to ongoing electroencephalography (EEG) and magnetoencephalography (MEG). However, those studies focused on healthy subjects, and failed to examine the group-level comparisons during music listening. Here, we combined group-level spatial Fourier ICA with acoustic feature extraction, to enable group comparisons in frequency-specific brain networks of musical feature processing. It was then applied to healthy subjects and subjects with major depressive disorder (MDD). The music-induced oscil…