A replication and migration strategy on the hierarchical architecture in the fog computing environment

2020 ◽  
Vol 16 (3) ◽  
pp. 291-307
Author(s):  
Ahmed Berkennou ◽  
Ghalem Belalem ◽  
Said Limam
Keyword(s):  
Fog Computing ◽  
Hierarchical Architecture ◽  
Computing Environment ◽  
Huge Amount ◽  
Migration Strategy ◽  
Replication Strategy ◽  
Promising Solution ◽  
Network Usage ◽  
And Migration ◽  
Do So

Connecting objects have increasingly become popular in recent years, leading to the connection of more than 50 billion objects by the end of 2020. This large number of objects will generate a huge amount of data that is currently being processed and stored in the cloud. Fog Computing presents a promising solution to the problems of high latency and huge network traffic encountered in the cloud. As Fog’s infrastructures are dense, heterogeneous and geo-distributed, managing the data in order to satisfy users demand in such context is very complicated. In this work, we propose a data management strategy called ‘RMS-HaFC’ in which we consider the characteristics of Fog Computing environment. To do so, we proposed a hierarchical multi-layer model, on which we designed a migration and replication strategy based on data popularity. These strategies duplicate files dynamically and store them in different locations to improve the response time of users requests and minimize the system energy consumption without loading network usage. The strategy was evaluated using the iFogSim simulator and the experimental results obtained are very promising.

scholarly journals Support Mobile Fog Computing Test in piFogBedII

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1900
Author(s):  
Qiaozhi Xu ◽  
Junxing Zhang ◽  
Bulganmaa Togookhuu
Keyword(s):  
Smart Cities ◽  
Fog Computing ◽  
Research Field ◽  
Smart Devices ◽  
Production Environment ◽  
Migration Strategy ◽  
Smart Transportation ◽  
Simulation Tools ◽  
And Migration ◽  
New Research

IoT and 5G technologies are making smart devices, medical devices, cameras and various types of sensors become parts of the Internet, which provides feasibility to the realization of infrastructure and services such as smart homes, smart cities, smart medical technology and smart transportation. Fog computing (edge computing) is a new research field and can accelerate the analysis speed and decision-making for these delay-sensitive applications. It is very important to test functions and performances of various applications and services before they are deployed to the production environment, and current evaluations are more based on various simulation tools; however, the fidelity of the experimental results is a problem for most of network simulation tools. PiFogBed is a fog computing testbed built with real devices, but it does not support the testing of mobile end devices and mobile fog applications. The paper proposes the piFogBedII to support the testing of mobile fog applications by modifying some components in the piFogBed, such as extending the range of end devices, adding the mobile and migration management strategy and inserting a container agent to implement the transparent transmission between end devices and containers. The evaluation results show that it is effective and the delay resulting from the migration strategy and container agent is acceptable.

Denmark-Norway as a Potential World Power in the Early Seventeenth Century

Itinerario ◽  
2009 ◽  
Vol 33 (2) ◽  
pp. 17-27 ◽  
Author(s):  
Már Jónsson
Keyword(s):  
Foreign Affairs ◽  
The Political ◽  
Military Operations ◽  
Huge Amount ◽  
Northern Germany ◽  
Lower Saxony ◽  
One Year ◽  
Council Of State ◽  
Standing Army ◽  
Do So

On 2 January 1625, the English ambassador Robert Anstruther met with King Christian IV of Norway and Denmark and requested his participation in a union of Protestant states against Emperor Ferdinand II and the Catholic League in Germany. Within three days, King Christian proposed to contribute five thousand soldiers for one year, as part of an army of almost thirty thousand men. In early June, despite opposition from the Danish Council of State, reluctant to put a huge amount of money into foreign affairs, Christian decided to join what he called “the war for the defence of Lower Saxony”. He then headed an army of mercenaries southwards through Lower Saxony, secured all crossings over the river Weser and prepared to confront the Catholic forces. On 29 November, it was decided that Denmark would be in charge of military operations in Northern Germany, whereas England and the United Provinces would provide a monthly subsidy. The political and military prospects for Denmark were excellent, to say the least. It had the fourth strongest navy in Europe (after Spain and the two new allies), and only a few years before the Danish warships had been described by a French observer as “merveilles de l'océan”. A small standing army of two regiments had recently been established and Denmark was the fourth European state to do so after France, Spain and the neighbouring Sweden.

scholarly journals Prevalence and genetic diversity of avian haemosporidian parasites in wild bird species of the order Columbiformes

2021 ◽  
Author(s):  
Yvonne R. Schumm ◽  
Dimitris Bakaloudis ◽  
Christos Barboutis ◽  
Jacopo G. Cecere ◽  
Cyril Eraud ◽  
...  
Keyword(s):  
Host Species ◽  
Large Scale ◽  
Phylogenetic Reconstruction ◽  
Bird Species ◽  
Avian Species ◽  
Blood Parasites ◽  
Migration Strategy ◽  
Haemosporidian Parasites ◽  
Multiplex Pcr Assay ◽  
And Migration

AbstractDiseases can play a role in species decline. Among them, haemosporidian parasites, vector-transmitted protozoan parasites, are known to constitute a risk for different avian species. However, the magnitude of haemosporidian infection in wild columbiform birds, including strongly decreasing European turtle doves, is largely unknown. We examined the prevalence and diversity of haemosporidian parasites Plasmodium, Leucocytozoon and subgenera Haemoproteus and Parahaemoproteus in six species of the order Columbiformes during breeding season and migration by applying nested PCR, one-step multiplex PCR assay and microscopy. We detected infections in 109 of the 259 screened individuals (42%), including 15 distinct haemosporidian mitochondrial cytochrome b lineages, representing five H. (Haemoproteus), two H. (Parahaemoproteus), five Leucocytozoon and three Plasmodium lineages. Five of these lineages have never been described before. We discriminated between single and mixed infections and determined host species-specific prevalence for each parasite genus. Observed differences among sampled host species are discussed with reference to behavioural characteristics, including nesting and migration strategy. Our results support previous suggestions that migratory birds have a higher prevalence and diversity of blood parasites than resident or short-distance migratory species. A phylogenetic reconstruction provided evidence for H. (Haemoproteus) as well as H. (Parahaemoproteus) infections in columbiform birds. Based on microscopic examination, we quantified parasitemia, indicating the probability of negative effects on the host. This study provides a large-scale baseline description of haemosporidian infections of wild birds belonging to the order Columbiformes sampled in the northern hemisphere. The results enable the monitoring of future changes in parasite transmission areas, distribution and diversity associated with global change, posing a potential risk for declining avian species as the European turtle dove.

Security challenges in fog-computing environment: a systematic appraisal of current developments

2019 ◽  
Vol 5 (4) ◽  
pp. 209-233 ◽  
Author(s):  
Jimoh Yakubu ◽  
Shafi’i Muhammad Abdulhamid ◽  
Haruna Atabo Christopher ◽  
Haruna Chiroma ◽  
Mohammed Abdullahi
Keyword(s):  
Fog Computing ◽  
Computing Environment ◽  
Security Challenges ◽  
Systematic Appraisal
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