1,392 research outputs found
Dynamic RPL for Multi-hop Routing in IoT Applications
The Routing Protocol for Low Power and Lossy Networks (RPL) has become the standard routing protocol for the Internet of Things (IoT). This paper investigates the use of RPL in dynamic networks and presents an enhanced RPL for different applications with dynamic mobility and diverse network requirements. This implementation of RPL is designed with a new dynamic Objective-Function (D-OF) to improve the Packet Delivery Ratio (PDR), end-to-end delay and energy consumption while maintaining low packet overhead and loop-avoidance. We propose a controlled reverse-trickle timer based on received signal strength identification (RSSI) readings to maintain high responsiveness with minimum overhead and consult the objective function when a movement or an inconsistency is detected to help nodes make an informed decision. Simulations are done using Cooja with random waypoint mobility scenario for healthcare applications considering multi-hop routing. The results show that the proposed dynamic RPL (D-RPL) adapts to the nodes mobility and has a higher PDR, slightly lower end-to-end delay and reasonable energy consumption compared to related existing protocols
Delay Contributing Factors and Strategies Towards Its Minimization in IoT
Internet of Things (IoT) refers to various interconnected devices, typically supplied with limited computational and communication resources. Most of the devices are designed to operate with limited memory and processing capability, low bandwidth, short range and other characteristics of low cost hardware. The resulting networks are exposed to traffic loss and prone to other vulnerabilities. One of the major concerns is to ensure that the network communication among these deployed devices remains at required level of Quality of Service (QoS) of different IoT applications. The purpose of this paper is to highlight delay contributing factors in Low Power and Lossy Networks (LLNs) since providing low end-to-end delay is a crucial issue in IoT environment especially for mission critical applications. Various research efforts in relevance to this aspect are then presente
Youth Unemployment, Ageing and Regional Welfare: The Regional Labour Market Policy Response to Ageing in Sweden
The aim of this paper is to discuss the regional labour market policy response to demographic ageing in Sweden and its consequences on the labour supply of young adults. Regions with ageing problems already experience significant problems at the labour market. The overall conclusion is that labour market policies in Sweden addressing the consequences of ageing fail to include young adults and the policies do not address regional heterogeneity regarding e.g. ageing and youth unemployment
Performance Assessment of Routing Protocols for IoT/6LoWPAN Networks
The Internet of Things (IoT) proposes a disruptive communication paradigm that allows
smart objects to exchange data among themselves to reach a common goal. IoT application
scenarios are multiple and can range from a simple smart home lighting system to fully controlled
automated manufacturing chains. In the majority of IoT deployments, things are equipped with
small devices that can suffer from severe hardware and energy restrictions that are responsible
for performing data processing and wireless communication tasks. Thus, due to their features,
communication networks that are used by these devices are generally categorized as Low Power
and Lossy Networks (LLNs).
The considerable variation in IoT applications represents a critical issue to LLN networks,
which should offer support to different requirements as well as keeping reasonable
quality-of-service (QoS) levels. Based on this challenge, routing protocols represent a key issue
in IoT scenarios deployment. Routing protocols are responsible for creating paths among devices
and their interactions. Hence, network performance and features are highly dependent
on protocol behavior. Also, based on the adopted protocol, the support for some specific requirements
of IoT applications may or may not be provided. Thus, a routing protocol should be
projected to attend the needs of the applications considering the limitations of the device that
will execute them.
Looking to attend the demand of routing protocols for LLNs and, consequently, for IoT
networks, the Internet Engineering Task Force (IETF) has designed and standardized the IPv6
Routing Protocol for Low Power and Lossy Networks (RPL). This protocol, although being robust
and offering features to fulfill the need of several applications, still presents several faults and
weaknesses (mainly related to its high complexity and memory requirement), which limits its
adoption in IoT scenarios. An alternative to RPL, the Lightweight On-demand Ad Hoc Distancevector
Routing Protocol – Next Generation (LOADng) has emerged as a less complicated routing
solution for LLNs. However, the cost of its simplicity is paid for with the absence of adequate
support for a critical set of features required for many IoT environments. Thus, based on the
challenging open issues related to routing in IoT networks, this thesis aims to study and propose
contributions to better attend the network requirements of IoT scenarios. A comprehensive survey,
reviewing state-of-the-art routing protocols adopted for IoT, identified the strengths and
weaknesses of current solutions available in the literature. Based on the identified limitations,
a set of improvements is designed to overcome these issues and enhance IoT network performance.
The novel solutions are proposed to include reliable and efficient support to attend
the needs of IoT applications, such as mobility, heterogeneity, and different traffic patterns.
Moreover, mechanisms to improve the network performance in IoT scenarios, which integrate
devices with different communication technologies, are introduced.
The studies conducted to assess the performance of the proposed solutions showed
the high potential of the proposed solutions. When the approaches presented in this thesis
were compared with others available in the literature, they presented very promising results
considering the metrics related to the Quality of Service (QoS), network and energy efficiency,
and memory usage as well as adding new features to the base protocols. Hence, it is believed
that the proposed improvements contribute to the state-of-the-art of routing solutions for IoT
networks, increasing the performance and adoption of enhanced protocols.A Internet das Coisas, do inglês Internet of Things (IoT), propõe um paradigma de
comunicação disruptivo para possibilitar que dispositivos, que podem ser dotados de comportamentos
autónomos ou inteligentes, troquem dados entre eles buscando alcançar um objetivo
comum. Os cenários de aplicação do IoT são muito variados e podem abranger desde um simples
sistema de iluminação para casa até o controle total de uma linha de produção industrial. Na
maioria das instalações IoT, as “coisas” são equipadas com um pequeno dispositivo, responsável
por realizar as tarefas de comunicação e processamento de dados, que pode sofrer com severas
restrições de hardware e energia. Assim, devido às suas características, a rede de comunicação
criada por esses dispositivos é geralmente categorizada como uma Low Power and Lossy Network
(LLN).
A grande variedade de cenários IoT representam uma questão crucial para as LLNs,
que devem oferecer suporte aos diferentes requisitos das aplicações, além de manter níveis
de qualidade de serviço, do inglês Quality of Service (QoS), adequados. Baseado neste desafio,
os protocolos de encaminhamento constituem um aspecto chave na implementação de
cenários IoT. Os protocolos de encaminhamento são responsáveis por criar os caminhos entre
os dispositivos e permitir suas interações. Assim, o desempenho e as características da rede
são altamente dependentes do comportamento destes protocolos. Adicionalmente, com base
no protocolo adotado, o suporte a alguns requisitos específicos das aplicações de IoT podem
ou não ser fornecidos. Portanto, estes protocolos devem ser projetados para atender as necessidades
das aplicações assim como considerando as limitações do hardware no qual serão
executados.
Procurando atender às necessidades dos protocolos de encaminhamento em LLNs e,
consequentemente, das redes IoT, a Internet Engineering Task Force (IETF) desenvolveu e padronizou
o IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). O protocolo, embora
seja robusto e ofereça recursos para atender às necessidades de diferentes aplicações, apresenta
algumas falhas e fraquezas (principalmente relacionadas com a sua alta complexidade e
necessidade de memória) que limitam sua adoção em cenários IoT. Em alternativa ao RPL, o
Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng)
emergiu como uma solução de encaminhamento menos complexa para as LLNs. Contudo, o
preço da simplicidade é pago com a falta de suporte adequado para um conjunto de recursos
essenciais necessários em muitos ambientes IoT. Assim, inspirado pelas desafiadoras questões
ainda em aberto relacionadas com o encaminhamento em redes IoT, esta tese tem como objetivo
estudar e propor contribuições para melhor atender os requisitos de rede em cenários IoT.
Uma profunda e abrangente revisão do estado da arte sobre os protocolos de encaminhamento
adotados em IoT identificou os pontos fortes e limitações das soluções atuais. Com base nas debilidades
encontradas, um conjunto de soluções de melhoria é proposto para superar carências
existentes e melhorar o desempenho das redes IoT. As novas soluções são propostas para incluir
um suporte confiável e eficiente capaz atender às necessidades das aplicações IoT relacionadas
com suporte à mobilidade, heterogeneidade dos dispositivos e diferentes padrões de tráfego.
Além disso, são introduzidos mecanismos para melhorar o desempenho da rede em cenários IoT
que integram dispositivos com diferentes tecnologias de comunicação.
Os vários estudos realizados para mensurar o desempenho das soluções propostas mostraram
o grande potencial do conjunto de melhorias introduzidas. Quando comparadas com
outras abordagens existentes na literatura, as soluções propostas nesta tese demonstraram um aumento do desempenho consistente para métricas relacionadas a qualidade de serviço, uso de
memória, eficiência energética e de rede, além de adicionar novas funcionalidades aos protocolos
base. Portanto, acredita-se que as melhorias propostas contribuiem para o avanço do estado
da arte em soluções de encaminhamento para redes IoT e aumentar a adoção e utilização dos
protocolos estudados
A single tDCS session can enhance numerical competence
While numerical skills are increasingly important in modern life, few interventions have been developed to support those with numeracy skills difficulties. Previous studies have demonstrated that applying transcranial Direct Current Stimulation (tDCS) can improve numerical skills. However, tDCS interventions designed to induce lasting changes typically involve reapplying brain-stimulation over several days. Repeated tDCS application can increase the risks associated with the procedure, as well as restricts the transferability of the method to a wider population, particularly those who may experience mobility issues, such as stroke survivors with acalculia. The current study investigated whether a single session of tDCS (anodal to right parietal lobe and cathodal to left parietal lobe), followed by four self-practice sessions without tDCS, could result in enhancement of numerical skills. Nineteen healthy adults (n = 10 tDCS, n = 9 sham control) implicitly learnt the magnitude association of nine arbitrary symbols, previously used by Cohen Kadosh et al. (2010). Numerical proficiency was assessed using number-to-space task, while automaticity was assessed with numerical Stroop. Results revealed that single-session tDCS had a significant effect on participants' accuracy on the number-to-space tasks, but not on the numerical Stroop task's congruity effect, implying automaticity may require longer practice. We conclude that a single session of tDCS should be considered as an avenue for interventions
Cross-border Previous Learning Recognition: Enhancing Lifelong Learning and Social Inclusion
[EN] Regarded as a social advancement tool, Previous Learning Recognition (RPL) processes' development in cross-border regions should enable the transferring of qualified and Higher Education graduated workforce across territories. Within the project LLL-Transversalis, French universities have been establishing RPL assessement events with international participants (Spanish and Andorran) in order to build a cross-border RPL system in the Pyrenees region. This paper exposes the characteristiques of these unique RPL processes and the results obtained. So far, eleven events have been developed, accrediting students in the domains of Engineering, Tourism and Management. Jurys were compounded on average of 7 members from both academic and professional worlds and observers from Spain and Andorra were present. Feedback from international participants is highly positive. Due to the economic and social crisis caused by Covid-19, cross-border and national RPL could turn out to be an effective way to galvanize human capital growth in the following years, hence the value of this project's actions. Taking advantage of mobility restrictions caused by the sanitary crisis, the first online cross-border RPL events will take place later this year, setting a starting point for further research and innovation on these practices in Spain and Andorra with the help of French institutions.Cobos Rius, H.; Boumeggoti, D.; Fortó Areny, J.; Sabrià Bernadó, B. (2021). Cross-border Previous Learning Recognition: Enhancing Lifelong Learning and Social Inclusion. En 7th International Conference on Higher Education Advances (HEAd'21). Editorial Universitat Politècnica de València. 473-480. https://doi.org/10.4995/HEAd21.2021.12972OCS47348
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