Search results for "Network model"
showing 9 items of 69 documents
Energy balance in single exposure multispectral sensors
2013
International audience; Recent simulations of multispectral sensors are based on a simple Gaussian model, which includes filters transmittance and substrate absorption. In this paper we want to make the distinction between these two layers. We discuss the balance of energy by channel in multispectral solid state sensors and propose an updated simple Gaussian model to simulate multispectral sensors. Results are based on simulation of typical sensor configurations.
Overlapping Community Structure in Co-authorship Networks: A Case Study
2014
Community structure is one of the key properties of real-world complex networks. It plays a crucial role in their behaviors and topology. While an important work has been done on the issue of community detection, very little attention has been devoted to the analysis of the community structure. In this paper, we present an extensive investigation of the overlapping community network deduced from a large-scale co-authorship network. The nodes of the overlapping community network represent the functional communities of the co-authorship network, and the links account for the fact that communities share some nodes in the co-authorship network. The comparative evaluation of the topological prop…
Modeling and predicting the Spanish Bachillerato academic results over the next few years using a random network model
2016
[EN] Academic performance is a concern of paramount importance in Spain, where around of 30% of the students in the last two courses in high school, before to access to the labor market or to the university, do not achieve the minimum knowledge required according to the Spanish educational law in force. In order to analyze this problem, we propose a random network model to study the dynamics of the academic performance in Spain. Our approach is based on the idea that both, good and bad study habits, are a mixture of personal decisions and influence of classmates. Moreover, in order to consider the uncertainty in the estimation of model parameters, we perform a lot of simulations taking as t…
Distribution of oxygen partial pressure in a two-dimensional tissue supplied by capillary meshes and concurrent and countercurrent systems
1969
Abstract For the calculations of oxygen partial pressure in a two-dimensional tissue model supplied by a capillary network (inhomogeneously perfused tissue), two differential equations are given that describe the process in the tissue and capillaries. The differential equations are coupled by the boundary conditions. Results obtained by using the method of successive displacements are given for the two-dimensional problem. This method exhibits a satisfactory convergence. The accuracy of the results is about ±5% based on the initial concentration. The results for the network model are compared with those for equivalent concurrent and countercurrent systems. Equivalence means in this connecti…
Closed Form Approximation of Swap Exposures
2013
This paper provides closed form lower and upper bounds for the price of European swaption on cross currency basis swap with the presence of dynamic basis spreads. Cross currency basis spreads are treated as integrals of spot spreads, approach familiar from interest rate models. The spot spread is modelled by two-factor mean reverting Gaussian model that is equivalent to two-factor Hull-White model introduced by [Hull and White(1994)]. This model allows closed form approximations and relatively well fitting and simple calibration to the spread term structure.
Social network analysis: the use of graph distances to compare artificial and criminal networks
2021
Aim: Italian criminal groups become more and more dangerous spreading their activities into new sectors. A criminal group is made up of networks of hundreds of family gangs which extended their influence across the world, raking in billions from drug trafficking, extortion and money laundering. We focus in particular on the analysis of the social structure of two Sicilian crime families and we used a Social Network Analysis approach to study the social phenomena. Starting from a real criminal network extracted from meetings emerging from the police physical surveillance during 2000s, we here aim to create artificial models that present similar properties. Methods: We use specific tools of s…
Pressure Dependence of the Band Gaps and Charge Densities in Si
1994
The empirical local and nonlocal pseudopotentials of Si which can describe the electronic energy structure over a wide energy range of more than 20 eV from the bottom of the valence band is determined for different pressures. The nonlocality of the potential is described by the Gaussian model. The predictions for the linear and quadratic pressure coefficients are consistent with the experiment. The valence charge densities of Si under high pressure are studied. The forbidden X-ray factor F(222) is very stable under pressure and changes by less than 3% under volume changes of the order of 5%.
Data from: Species’ ecological functionality alters the outcome of fish stocking success predicted by a food-web model
2018
Fish stocking is used worldwide in conservation and management but its effects on food-web dynamics and ecosystem stability are poorly known. To better understand these effects and predict the outcomes of stocking, we used an empirically validated network model of a well-studied lake ecosystem. We simulate two stocking scenarios with two native fish species valuable for fishing. In the first scenario, we stock planktivorous fish (whitefish) larvae in the ecosystem. This leads to 1% increase in adult whitefish biomasses and decreases the biomasses of the top predator (perch). In the second scenario, we also stock perch larvae in the ecosystem. This decreases the planktivorous whitefish and t…
Terahertz Absorption change in Photosynthetic Reaction Center upon photoactivation
2012
Photosynthetic reaction center is a membrane protein which plays an important role in converting solar energy into chemical energy. Upon continuous illumination a charge separation occurs within the protein which is stable for several seconds [1]. The stability of this state is very important to protect the protein against the release of excess heat and an instable radical due to charge recombination. Absorption of terahertz radiation corresponds to the excitation of large vibrations in the protein and is thus suitable for studying its different dynamical states. Here we recorded terahertz absorption spectra of the dark and illuminated state of reaction centre from the purple membrane bacte…