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[en] Quantum entanglement is a crucial element of establishing the entangled network structure of the quantum Internet. Here we define a method to achieve controlled entanglement access in the quantum Internet. The proposed model defines different levels of entanglement accessibility for the users of the quantum network. The path cost is determined by an integrated criterion on the entanglement fidelities between the quantum nodes and the probabilities of entangled connections of an entangled path. We reveal the connection between the number of available entangled paths and the accessible fidelity of entanglement and reliability in the end nodes. The scheme provides an efficient model for entanglement access control in the experimental quantum Internet.
[en] The article Demonstration of entanglement purification and swapping protocol to design quantum repeater in IBM quantum computer, written by Bikash K. Behera, Swarnadeep Seth, Antariksha Das, Prasanta K. Panigrahi, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 1 March 2019 with open access.
[en] Analyzing shareability of correlations arising in any physical theory may be considered as a fruitful technique of studying the theory. Our present topic of discussion involves an analogous approach of studying quantum theory. For our purpose, we have deviated from the usual procedure of assessing monogamous nature of quantum correlations in the standard Bell-CHSH scenario. We have considered correlations arising in a quantum network involving independent sources. Precisely speaking, we have analyzed monogamy of nonbilocal correlations by deriving a relation restricting marginals. Interestingly, restrictions constraining distribution of nonbilocal correlations remain same irrespective of whether inputs of the nodal observers are kept fixed (in different bilocal networks) while studying nonbilocal nature of marginal correlations.
[en] A bidirectional fiber-free-space optical (FSO)/wireless convergent system that uses dual-polarization and one optical sideband transmission schemes for hybrid vestigial sideband (VSB)–four-level pulse amplitude modulation (PAM4)/millimeter-wave signal transmission is proposed and demonstrated. Using a dual-polarization scheme, one optical sideband that is modulated by a 56 Gb s−1 VSB–PAM4 signal (x-polarization) and another optical sideband that is modulated by a 10 Gbps data stream (y-polarization) are separated and polarized orthogonally. One optical sideband modulated by a 10 Gbps data stream (y-polarization) is delivered to efficaciously suppress the dispersion-induced limitation due to a span of 40 km single-mode fiber (SMF) and the distortion due to the beating among multiple sidebands. The proposed bidirectional fiber-FSO/wireless convergent system is a prominent one for providing broadband integrated services, such as the Internet, telecommunication, and 5G mobile networks. (paper)
[en] This study focuses on whether information and communication technology (ICT) contributes to economic growth in countries with better human development index as compared to those with a lower index. The study uses panel data estimation methods those are robust to dependencies across countries and heterogeneity from 1990 to 2016 in developing Asian countries. The results documented that countries with better human development index and mobile phone usage promote economic growth, whereas Internet users do not seem to do so. Despite that, human development index itself is a critical factor that contributes to economic growth in Asian countries. Finally, both mobile phone usages contribute to economic growth, but Internet usage does not seem to do. These new findings recommend that whereas better human development is regarded as crucial for mobile phone usage, it appears to be inappropriate for Internet usage. An additional feature is that the study uses the most robust panel data estimation method that produces more effective and reliable estimates.
[en] The article Cellular distribution of cadmium in two amaranth (Amaranthus mangostanus L.) cultivars differing in cadmium accumulation, written by Keyu Chi, Rong Zou, Li Wang, Wenmin Huo and Hongli Fan, was originally published electronically on the publisher’s internet portal (currently SpringerLink)
[en] Our understanding of how diseases spread has greatly benefited from advances in network modeling. However, despite of its importance for disease contagion, the directionality of edges has rarely been taken into account. On the other hand, the introduction of the multilayer framework has made it possible to deal with more complex scenarios in epidemiology such as the interaction between different pathogens or multiple strains of the same disease. In this work, we study in depth the dynamics of disease spreading in directed multilayer networks. Using the generating function approach and numerical simulations of a stochastic susceptible-infected-susceptible model, we calculate the epidemic threshold of synthetic and real-world multilayer systems and show that it is mainly determined by the directionality of the links connecting different layers, regardless of the degree distribution chosen for the layers. Our findings are of utmost interest given the ubiquitous presence of directed multilayer networks and the widespread use of disease-like spreading processes in a broad range of phenomena such as diffusion processes in social and transportation systems. (paper)
[en] With the increase in the number of Internet users and an explosion in mobile use, the digital sector is living a golden age which is reflected by an exponential growth in the number of devices connected to the Internet and by an explosion of IP traffic in telecom networks and data centers. However, this revolution is not without consequences for digital energy consumption, which is also growing at a sustained rate. According to the Shift Project, between 2013 and 2017, global digital consumption increased by 50 pc, from 2000 to 3000 TWh per year. By way of comparison, over this same period, global electricity consumption grew by just under 10 pc and reached 21,500 TWh in 2017. By 2025, digital energy consumption should continue to grow at an annual rate of 10 pc and could be between 5,700 and 7,300 TWh in 2025. While the growth in digital consumption is driven by all of its segments - terminal equipment, telecom networks, data centers and production of said equipment and infrastructure -, the production has been in recent years and will remain by 2025 the main item of digital consumption: it represents 45 pc of total consumption in the sector and this share should remain around 40 pc by 2025. The energy growth of digital is particularly strong compared to the growth in global energy consumption in all sectors: in 2017, digital technology represented around 2.7 pc of global final energy consumption at the global level and should represent in 2025 between 4.7 pc and 6 pc, almost doubling compared to 2017. The translation of this energy consumption into greenhouse gas emissions is also worrying: the digital represents 3.4 pc of total GHG emissions in 2017 or 1.8 GtCO2e and should represent 7.6 pc in 2025 or 3.7 GtCO2e. Two emerging technologies are also giving rise to strong fears in energy terms: cryptocurrencies and the Internet of Things. Cryptocurrencies based on public blockchains are indeed an engine of the growth of digital energy consumption, but to date represent a still small share of total consumption: between 60 and 200 TWh in 2018. This consumption is however often perceived as 'ineffective' with regard to the current social utility of cryptocurrencies and could be drastically reduced if 'proof of stake' systems were privileged. IoT equipment is the one whose consumption should increase the most by 2030. This growth should be mainly driven by the consumption of tens of billions of expected objects, while the additional consumption they induce upstream in telecom networks and data centers should remain weak. Production-related consumption, which is likely to be high, is not documented at this stage. In the end, the addition of a connection function to a multitude of objects should have an impact on the evolution of the overall digital consumption and the consumption of this new digital segment should therefore be studied. Faced with these challenges, the traditional response to the problems linked to the increasing energy consumption of digital technology relies mainly on energy gains linked to technological progress. Technological progress in large digital infrastructures (telecom networks and data centers) allows real unit energy gains: for example, concerning fixed access networks, PON optical fiber networks consume between 0.2 and 0.8 W / user against 3 and 5 W / user for VDSl copper networks. Nevertheless, the inefficiencies that persist in the management of infrastructures (in particular the existence in parallel of several generations of telecom networks and the non-optimization of the rate of use of equipment in data centers) and especially the increase in uses and fine internet traffic, do not allow overall consumption to be controlled. In addition, this lever does not act on energy consumption linked to the production of equipment and therefore leaves out a major item of digital consumption.
[fr]Avec un double phenomene d'augmentation du nombre des internautes et d'explosion des usages mobiles, le secteur numerique vit un age d'or qui se traduit dans les faits par une croissance exponentielle du nombre d'equipements connectes a internet et par une explosion du trafic IP dans les reseaux telecoms et les data centers. Cette revolution n'est cependant pas sans consequence sur la consommation energetique du numerique, qui croit elle aussi a un rythme soutenu. Ainsi, selon le Shift Project, en seulement cinq ans, entre 2013 et 2017, la consommation globale du numerique a augmente de 50 pc, passant de 2000 a 3000 TWh par an. A titre de comparaison, sur cette meme periode, la consommation electrique mondiale a cru d'un peu moins de 10 pc et atteignait 21 500 TWh en 2017. D'ici 2025, la consommation energetique du numerique devrait continuer a croitre a un rythme annuel de 10 pc et pourrait se situer entre 5700 et 7300 TWh en 2025. Si la croissance de la consommation du numerique est portee par l'ensemble de ses segments - equipements terminaux, reseaux telecoms, data centers et production desdits equipements et infrastructures -, la production a ete ces dernieres annees et restera a horizon 2025 le principal poste de consommation du numerique: elle represente 45 pc de la consommation totale du secteur et cette part devrait rester aux alentours de 40 pc d'ici 2025. La croissance energetique du numerique est particulierement forte comparee a la croissance de la consommation energetique mondiale tous secteurs confondus: en 2017, le numerique represente environ 2,7 pc de la consommation globale d'energie finale au niveau mondial et devrait en representer en 2025 entre 4,7 pc et 6 pc, soit un quasiment doublement par rapport a 2017. La traduction de cette consommation d'energie en emissions de gaz a effet de serre est elle aussi inquietante: le numerique represente 3,4 pc des emissions totales de GES en 2017 soit 1,8 GtCO2e et devrait representer 7,6 pc en 2025 soit 3,7 GtCO2e. Deux technologies emergentes suscitent par ailleurs de fortes craintes en termes energetiques: les crypto-monnaies et l'internet des objets. Les crypto-monnaies reposant sur des blockchains publiques constituent bien un moteur de la croissance de la consommation energetique du numerique, mais representent a ce jour une part encore faible de la consommation totale: entre 60 et 200 TWh en 2018. Cette consommation est cependant souvent percue comme 'non efficace' au regard de l'utilite sociale actuelle des crypto-monnaies et pourrait etre drastiquement reduite si les systemes de preuve de participation etaient privilegies. La consommation energetique de l'internet des objets est encore peu etudiee. On sait cependant que les equipements IoT sont ceux dont la consommation devrait croitre le plus a horizon 2030. Cette croissance devrait etre essentiellement portee par la consommation des dizaines de milliards d'objets attendus, tandis que la consommation supplementaire qu'ils induisent en amont dans les reseaux telecoms et les data centers devrait rester faible. La consommation liee a la production, qui risque d'etre elevee, n'est a ce stade pas documentee. Au final, l'adjonction d'une fonction de connexion a une multitude d'objets devrait avoir une incidence sur l'evolution de la consommation globale du numerique et la consommation de ce nouveau segment du numerique devrait, des lors, etre etudiee. Face a ces enjeux, la reponse traditionnelle aux problemes lies a la consommation energetique croissante du numerique a repose et repose encore essentiellement sur les gains energetiques lies au progres technologique. Le progres technologique dans les grandes infrastructures numeriques - reseaux telecoms et data centers - permet de reels gains energetiques unitaires: par exemple, concernant les reseaux d'acces fixe, les reseaux en fibre optique PON consomment entre 0,2 et 0,8 W/utilisateur contre 3 et 5W/utilisateur pour les reseaux cuivre VDSl. Neanmoins, les inefficacites qui perdurent dans la gestion des infrastructures (notamment l'existence en parallele de plusieurs generations de reseaux telecoms et la non-optimisation du taux d'utilisation des equipements dans les data centers) et surtout l'accroissement des usages et in fine du trafic internet, ne permettent pas de maitriser la consommation globale. Par ailleurs, ce levier n'agit pas sur la consommation energetique liee a la production des equipements et laisse donc de cote un poste majeur de la consommation du numerique. Ce document de travail, deuxieme d'une serie de trois documents, s'appuie sur les travaux presentes lors d'un cycle de seminaires sur l'impact environnemental du numerique qui s'est tenu a France Strategie en 2018-2019. (auteurs)
[en] Studying the topology of infrastructure communication networks (e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems (ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales (i.e., nodes, edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges (as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series, which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes, edges and components, and therefore our study represents an innovative approach to the subject. (paper)
[en] The article Temporal trends of contaminants in Arctic human populations, written by Khaled Abass, Anastasia Emelyanova and Arja Rautio, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 25 August 2018 without open access.