Une étude de cas : examen de l’effet de la pluie sur neige à l’aide des micro-ondes passives

Abstract: The environmental and anthropocentric forcings have a significant impact on climate change and the rate at which it is happening. Even if the rain on snow (ROS) events are known to be an important part of the previously mentioned forcings, they are not taken into consideration in global climate models given the absence of a yet reliable empiric method for detecting their occurrence. Previous research has shown that the 19 GHz and 37 GHz passive microwave frequencies are highly sensitive to presence of liquid water within the snow column. By examining the normalized gradient (GR) of the polarized components, horizontal (H) and vertical (V), of the previously mentioned frequencies, we have created a ROS detection approach using the gradient ratios between GRV and GRH gradients. The validation of the approach using AMSR-E data over known ROS events (in-situ observed meteorological data) demonstrates the promising potential of the index and suggests that further research into this subject might allow us to create a reliable and operational remote sensing ROS detection method.L’Arctique est une des régions de notre planète les plus sensibles au réchauffement climatique. Les effets de pluie sur neige ne sont pas pris en considération dans les modèles climatiques globaux ainsi augmentant leurs incertitudes. La présence de l’eau dans une colonne de neige a un impact direct sur l’albédo ainsi que sur les propriétés diélectriques de la neige. Même si ces effets ont un impact direct sur les propriétés de la neige, ce qui contribue d’une manière positive au réchauffement climatique, il n’existe pas une méthode empirique de détection de ce phénomène. Des recherches précédentes sur ce sujet on démontrée que les fréquences de 19 et 37 GHz dans les micro-ondes passives sont d’une grande sensibilité a la présence de l’eau dans la neige. Cet essai propose, analyse et réalise un test validation d’une méthode qui met en relation les polarisations verticales et horizontales des fréquences mentionnées précédemment [...] pour les fins de détection de phénomène de pluie sur neige. La présence de l’eau dans une colonne de neige va augmenter la température de brillance dans le 19V, 37H et 37H, mais pas pour le 19H. La température de brillance de ce dernier va diminuer. En créant un ratio de gradient entre les deux polarisations [...] le phénomène de pluie sur neige va provoquer des valeurs négatives de ce dernier, tandis que les valeurs positives indiqueront des circonstances météorologiques normales ou de fonte (non liée à la pluie sur neige). La validation de cette méthode, en utilisant des données d’AMSR-E et des observations météorologique humaines de l’Environnement Canada, indique des résultats prometteurs avec des faibles valeurs d’omission, de commission, et d’inexactitude. Une étude plus poussée permettra de réduire l’inexactitude de l’index proposé et nous permettra d’obtenir une méthode empirique viable pour détecter le phénomène de pluie sur neige. [Symboles non conformes

Reiterating Asylum Archive: documenting direct provision in Ireland

Originally a coping mechanism for an artist housed in a Direct Provision Centres while seeking asylum in Ireland, Asylum Archive has become much more than that. In 2018, it is now a collaborative archive, interactive and intermedial online document, and a scholarly research project. This iteration includes five new images of Railway Direct Provision Centre in Kiltimagh

Supply Chain RFID Solution Evaluation Applying AHP and FAHP Methods: A Case Study of the Serbian Market

There has been a recent years tendency for replacing traditional supply chain data identifying and collecting systems with RFID (Radio Frequency Identification) technologies. There are different RFID solutions on the market and it is crucial to choose the solution that best suits the set of goals and desired scenarios. The choice of solution depends on a whole range of different factors and criteria. The present paper develops multi-criteria evaluation models based on the AHP (Analytic Hierarchy Process) and FAHP (Fuzzy Analytic Hierarchy Process) approach. There are no papers in the literature that solve the mentioned problem in this way, on a real example. Three RFID solutions are defined referring to different data identification levels in supply chains, namely: product level, level of packaging and the level of the pallet. Solutions are evaluated, and rated in relation to four criteria: investments, costs, participants\u27 visibility and participants\u27 privacy protection in supply chains. Developed models are tested and applied via a case study conducted in the Serbian market. The model is an excellent basis for decision-making in practice and for researchers in the literature, while with certain modifications, it can be used for other similar problems

A Reconfigurable Array Based Prototype of a Specialised String Lookup Chip

Different strategies for performing string lookups have been developed and deployed during the evolutionary scientific process. These are the results of both the development of technology and the need for improvement of previously existing solutions. Hence, the string lookup problem has been well studied and the respectful amount of good solutions is present. Due to nature of the problem, most of the solutions are software based. Nevertheless, in the modern computing environments, in which the amount of data to be searched trough is increasingly growing, the problem re-arises demanding for the different type of approaches that could target multi-gigabit throughput rates so as to perform close to real-time string lookups. In that light, this paper studies the potential of migrating, a well-known and widely used, Boyer-Moore string lookup algorithm to a hardware specific device capable of satisfying the demanded throughput, by proposing and characterising the initial implementation option on a reconfigurable platform

Rethinking Attention: Exploring Shallow Feed-Forward Neural Networks as an Alternative to Attention Layers in Transformers

This work presents an analysis of the effectiveness of using standard shallow feed-forward networks to mimic the behavior of the attention mechanism in the original Transformer model, a state-of-the-art architecture for sequence-to-sequence tasks. We substitute key elements of the attention mechanism in the Transformer with simple feed-forward networks, trained using the original components via knowledge distillation. Our experiments, conducted on the IWSLT2017 dataset, reveal the capacity of these "attentionless Transformers" to rival the performance of the original architecture. Through rigorous ablation studies, and experimenting with various replacement network types and sizes, we offer insights that support the viability of our approach. This not only sheds light on the adaptability of shallow feed-forward networks in emulating attention mechanisms but also underscores their potential to streamline complex architectures for sequence-to-sequence tasks.Comment: Accepted at AAAI24(https://aaai.org/aaai-conference/

Gibbs Sampling Approach to Markov Switching Models in Finance

In the present paper we apply the Gibbs Sampling approach to estimate the parameters of a MarkovSwitching Model which we use to model financial time series. In particular, we estimate the standard deviationof the time series in order to obtain an indicator similar to the VIX index. The Markov Switching technique hasbeen chosen because of the presence of exogenous factors which can have a large impact on the market, making itbehave differently in different time periods. We also perform a case study on the S&P500 index for the period 3January, 2007 - 29 December, 2014

Secondary schooling and rural youth transitions in Lesotho and Zimbabwe

Based on case studies centred on two rural secondary schools in Lesotho and Zimbabwe, this paper examines the gendered impacts of schooling on young people’s transitions to adulthood. School attendance is shown, first, to disrupt the conventional pathways to adulthood: young people attending school may leave home sooner than they otherwise would, and take responsibility for their day-to-day survival, while marriage and childbearing are often delayed. More significantly, secondary schooling reflects, and contributes to, a growing sense that adulthood itself is not fixed. An alternative version of adulthood is promoted through schools in which formal sector employment is central. Yet while young people are encouraged to opt for, and work towards, this goal, only a minority are able to obtain paid employment. The apparent possibility of determining one’s own lifecourse serves to cast the majority of young people as failures in their transitions to adulthood

GENTRIFICATION, CREATIVE CLASS AND PROBLEMS OF CONFLICT OF INTEREST IN CONTEMPORARY URBAN DEVELOPMENT

This paper considers modern city territories and analyzes neoliberal spatial city planning which is, among other things, mostly realized through gentrification. While explaining the modern transformation tendencies of cities the authors seek to find the link between the gentrification phenomenon and the rise of city inequality. In this context, marginality is not the result of economic underdevelopment but economic progress. The paper explores the reasons why contemporary urban politics leads to class segregation. The authors investigate a genetic connection of the capital and urbanization confirming Harvey’s paradigm that „capitalism is forced to urbanize in order to renew itself“. Furthermore, the paper investigates the relationship between creative class-creative city and to what extent it is reality and to what “a utopia for the chosen ones.