Search results for "Network"
showing 10 items of 7718 documents
Empirical Study on the Relationship between the Cross-Correlation among Stocks and the Stocks' Volatility Clustering
2013
In this paper we discuss univariate and multivariate statistical properties of volatility with the aim of understanding how these two aspects are interrelated. Specifically, we focus on the relationship between the cross-correlation among stock's volatilities and the volatility clustering. Volatility clustering is related to the memory property of the volatility time-series and therefore to its predictability. Our results show that there exists a relationship between the level of predictability of any volatility time-series and the amount of its inter-dependence with other assets. In all considered cases, the more the asset is linked to other assets, the more its volatility keeps memory of …
UAV-Aided Secure Short-Packet Data Collection and Transmission
2023
Benefiting from the deployment flexibility and the line-of-sight (LoS) channel conditions, unmanned aerial vehicle (UAV) has gained tremendous attention in data collection for wireless sensor networks. However, the high-quality air-ground channels also pose significant threats to the security of UAV aided wireless networks. In this paper, we propose a short-packet secure UAV-aided data collection and transmission scheme to guarantee the freshness and security of the transmission from the sensors to the remote ground base station (BS). First, during the data collection phase, the trajectory, the flight duration, and the user scheduling are jointly optimized with the objective of maximizing t…
Inverse problems and invisibility cloaking for FEM models and resistor networks
2013
In this paper we consider inverse problems for resistor networks and for models obtained via the finite element method (FEM) for the conductivity equation. These correspond to discrete versions of the inverse conductivity problem of Calderón. We characterize FEM models corresponding to a given triangulation of the domain that are equivalent to certain resistor networks, and apply the results to study nonuniqueness of the discrete inverse problem. It turns out that the degree of nonuniqueness for the discrete problem is larger than the one for the partial differential equation. We also study invisibility cloaking for FEM models, and show how an arbitrary body can be surrounded with a layer …
The Riverine Organism Drift Imager: A new technology to study organism drift in rivers and streams
2023
1. Drift or downstream dispersal is a fundamental process in the life cycle of many riverine organisms. In the face of rapidly declining freshwater biodiversity, there is a need to enhance our capacity to study the drift of riverine organisms, by overcoming the limitations of traditional labour-intensive sampling methods that result in data of low temporal and spatial resolution. 2. To address this need, we developed a new technology, the Riverine Organism Drift Imager (RODI), which combines in situ imaging with machine-learning classification. This technique expands on the traditional methodology by replacing the collection cup of a drift net with a camera system that continuously images r…
Promoting the Flexibility of Thermal Prosumers Equipped with Heat Pumps to Support Power Grid Management
2023
The increasing share of renewable energy sources in energy systems will lead to unpredictable moments of surplus/deficit in energy production. To address this issue, users with heat pumps can provide support to power grid operators through flexible unit operation achieved via Demand Response programs. For buildings connected to low-temperature heating networks with ensured third-party access, further room for flexibility can be explored by investigating the production of surplus heat that can be sold to the network. A key aspect lies in the identification of the energy pricing options that could encourage such flexible operation of a heat pump by “thermal prosumers”. To this aim…
A cost efficiency analysis of flood proofing measures for hydraulic risk mitigation in an Urbanized riverine area
2020
Non-structural measures for flood risk mitigation are often more economically accessible, easier to implement, and are highly effective, especially in view of the pursuit of risk resilience objectives. Among the non-structural measures, more importance is increasingly being attributed to flood proofing interventions. There are two main types of flood proofing: dry proofing and wet proofing. An example of dry proofing is shielding, which involves the use of flood barriers that can be installed in the entrances of buildings or outside the buildings in order to avoid contact with the houses and deviate the water flow. Their use must be supported by a detailed hydraulic analysis to ensure the c…
A deep learning segmentation approach to calories and weight estimation of food images
2019
Master's thesis Information- and communication technology IKT590 - University of Agder 2019 Today’s generation is very aware of what they are eating and the amountof calories in their food. Eating too many calories can lead to increasedweight, which has become a big health issue. A study from 2016 states thatmore than 1,9 billion adults are overweight where almost one third of theseare obese. Statistics from Norway show that 1 of 4 men and 1 of 5 womenare obese.Artificial Intelligence in general and deep learning in particular can be usedto help understand the content of eaten food. In this master thesis, wepropose a network to estimate the weight of food from a single image. Thisis done in…
Search strategies in innovation networks: The case of the Hungarian food industry
2020
In the food sector, open innovation has become of particular interest. This paper considers open innovation search strategies in the food and beverages industry and examines the probability of using different innovation sources with respect to the type of innovation. Although the information search for new ideas, tools and solutions in the innovation process regarding the scope and depth is well explored and interpreted in the literature, the probability of using the different sources with respect to type of innovation is rarely investigated. To answer these questions, first a probit, then OLS regression model is adopted, in order to understand the chance of a specific source of information…
Agri-Food Markets towards Sustainable Patterns
2020
In recent decades, the confluence of different global and domestic drivers has led to progressive and unpredictable changes in the functioning and structure of agri-food markets worldwide. Given the unsustainability of the current agri-food production, processing, distribution and consumption patterns, and the inadequate governance of the whole food system, the transition to sustainable agriculture and food systems has become crucial to effectively manage a global agri-food market able in supporting expected population growth and ensuring universal access to sufficient, safe, and nutritious food for all. Based on a critical review of the existing international literature, the paper seeks to…
Impact of electron beam irradiation on fish gelatin film properties
2016
International audience; The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino aci…