33 research outputs found
Robot Workspace Monitoring using a Blockchain-based 3D Vision Approach
Blockchain has been used extensively for financial purposes,
but this technology can also be beneficial in other
contexts where multi-party cooperation, security and decentralization
of the data is essential. Properties such as
immutability, accessibility and non-repudiation and the existence
of smart-contracts make blockchain technology very
interesting in robotic contexts that require event registration
or integration with Artificial Intelligence. In this paper,
we propose a system that leverages blockchain as a
ledger to register events and information to be processed
by Oracles and uses smart-contracts to control robots by
adjusting their velocity, or stopping them, if a person enters
the robot working space without permission. We show
how blockchain can be used in computer vision problems by
interacting with multiple external parties, Oracles, that perform
image analysis and how it is possible to use multiple
smart-contracts for different tasks. The method proposed is
shown in a scenario representing a factory environment, but
since it is modular, it can be easily adapted and extended for
other contexts, allowing for simple integration and maintenance.info:eu-repo/semantics/publishedVersio
Controlling Robots using Artificial Intelligence and a Consortium Blockchain
Blockchain is a disruptive technology that is normally used within financial
applications, however it can be very beneficial also in certain robotic
contexts, such as when an immutable register of events is required. Among the
several properties of Blockchain that can be useful within robotic
environments, we find not just immutability but also decentralization of the
data, irreversibility, accessibility and non-repudiation. In this paper, we
propose an architecture that uses blockchain as a ledger and smart-contract
technology for robotic control by using external parties, Oracles, to process
data. We show how to register events in a secure way, how it is possible to use
smart-contracts to control robots and how to interface with external Artificial
Intelligence algorithms for image analysis. The proposed architecture is
modular and can be used in multiple contexts such as in manufacturing, network
control, robot control, and others, since it is easy to integrate, adapt,
maintain and extend to new domains.info:eu-repo/semantics/submittedVersio
A QoS-aware architecture for mobile internet
Tese de doutoramento InformáticaHoje em dia, as pessoas pretendem ter simultaneamente mobilidade, qualidade de serviço e
estar sempre connectados à Internet. No intuito, de satisfazer estes clientes muito exigentes,
os mercados das telecomunicações estão a impor novos e dificeis desafios às redes móveis,
através da demanda, de heterogeneidade em termos de tecnologias de acesso rádio, novos
serviços, niveis de qualidade de serviço adequados aos requisitos das aplicações de tempo
real, elevada taxa de utilização do recursos disponiveis e melhor capacidade de desempenho.
A Internet foi concebida para fornecer serviços sem qualquer tipo de garantias de qualidade
à s aplicações, apenas se comprometendo em oferecer o melhor serviço possÃvel. No
entanto, nos útlimos anos diversos esforços foram levados a cabo no sentido de dotar a
Internet com o suporte à qualidade de serviço. Dos esforços desenvolvidos resultaram
dois paradigmas para o suporte da qualidade de serviço: o modelo de Serviços Integrados
(Integrated Services - IntServ) e o modelo de Serviços Diferenciados (Differentiated Services
- DiffServ). Todavia, estes modelos de qualidade de serviço (QoS) foram concebido antes
da existência da Internet móvel, portanto o desenvolvimento destes modelos não teve em
consideração a questão da mobilidade.
Por outro lado, o protocolo padrão actual para a Internet móvel, o MIPv6, revela algumas
limitações nos cenários onde os utilizadores estão constantemente a moverem-se para
outros pontos de acesso. Neste tipo de cenários, o MIPv6 introduz tempos de latência que
não são sustentáveis para aplicações com requisitos de QoS mais restritos. Os factos revelados,
demonstram que existe uma emergente necessidade de adaptar o actual protocolo de
mobilidade, e também de adaptar os modelos de QoS, ou então criar modelos alternativos
de QoS, para satisfazer às exigências do utilizador de hoje de redes móveis.
Para alcançar este objectivo o presente trabalho propõe melhorias no sistema de gestão
da mobilidade do protocolo MIPv6 e na gestão de recursos do modelo DiffServ. O MIPv6 foi
melhorado para os cenários de micro-mobilidade com a abordagem para micro-mobilidade do F-HMIPv6. Enquanto que, o modelo DiffServ foi melhorado para os ambientes móveis
com funcionalidades dinâmicas e adaptativas através da utilização de sinalização de QoS e
da gestão distribuida dos recursos.
A gestão da mobilidade e dos recursos foi também acoplada na solução proposta com o
propósito de optimizar a utilização dos recursos num meio onde os recursos são tipicamente
escassos.
O modelo proposto é simples, é de fácil implementação, tem em consideração os requisitos
da Internet móvel, e provou ser eficiente e capaz de fornecer serviços com QoS de
elevada fiabilidade às aplicações.Over the last few years, several network communication challenges have arisen as a
result of the growing number of users demanding Quality of Service (QoS) and mobility
simultaneously.
In order to satisfy these very demanding customers, the markets are imposing new
challenges to wireless networks by demanding heterogeneity in terms of wireless access
technologies, new services, suited QoS levels to real-time applications, high usability and
improved performance.
However, the Internet has been designed for providing application services without quality
guarantees. That explains why, in the last years several efforts have been made to
endow Internet with QoS support. From the developed efforts have resulted two QoS
paradigms: Integrated Services (IntServ) which offers the guaranteed service model and
the Differentiated Services (DiffServ) which offers the predictive service model.
Although these QoS models have been designed before the existence of mobile Internet,
so they do not consider the mobility issue. For instance, the guaranteed service model
requires that whenever a Mobile Node (MN) wants to move to a new location, the allocated
resources in the old path must be released and a new resource reservation in a new path must
be made, resulting in extra signaling overhead, heavy processing and state load. Therefore,
if handovers are frequent, large mobility and QoS signaling messages will be created in
the access networks. Consequently, significant scalability problems may arise with this type of
service model.
The predicted service model, on the other hand, requires an additional features such
as dynamic and adaptive resource management in order to be efficient in a very dynamic
network such as a mobile network.
A QoS solution for mobile environments must provide the capacity to adapt its resource
utilization to a changeable nature of wireless networks because they have a more dynamic behavior due to incoming or outgoing handovers. For this reason, a QoS signalization for
dynamic resource provisioning is necessary in order to supply adequate QoS levels to mobile
users.
On the other hand, the current standard protocol for mobile Internet, Mobile IPv6
(MIPv6), reveals limitations in scenarios where users are constantly moving to another
point of attachment. In these situations, MIPv6 introduces latency times that are not
sustainable for applications with strict QoS requirements.
All things considered, reveal the emerging need to adapt the current standard mobility
protocol and QoS models to satisfy today’s mobile user’s requirements.
To accomplish this goal, the present work proposes enhancements in terms of the MIPv6
protocol mobility management scheme as well as in DiffServ QoS model resource management.
The former was enhanced for micro-mobility scenarios with a specific combination of
FMIPv6 (Fast Mobile IPv6) and HMIPv6 (Hierarchical Mobile IPv6) protocols. Whereas,
the latter was enhanced for mobile environments with dynamic and adaptive features by
using QoS signalization as well as distributed resource management.
The mobility and resource management has also been coupled in the proposed solution
with the objective of optimizing the resource utilization in a environment where resources
are typically scarce.
In order to assess model performance as well as its parametrization, a simulation model
has been designed and implemented in the Network Simulator version two (NS-2).
The model´s performance evaluation has been conducted based on the respective data
acquired from statistical analysis in order to validate and consolidate the conclusions. Simulation
results indicate that the solution avoids network congestion and starvation of less
priority DiffServ classes.
Moreover, the results also indicate that bandwidth utilization for priority classes increases
and the QoS offered to MN’s applications, in each DiffServ class, remains unchangeable
with MN mobility.
The proposed model is simple and easy to implement. It considers mobile Internet
requirements and has proven to be effective and capable of providing services with highly
reliable QoS to mobile applications.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa SFRH/BD/35245/200
A QoS-enable solution for mobile environments
This paper addresses the problem of designing a suitable Quality of Service (QoS) solution for mobile environments. The proposed solution deploys a dynamic QoS provisioning scheme able to deal with service protection during node mobility within a local domain, presenting extensions to deal with global mobility. The dynamic QoS provisioning encompasses a QoS architecture that uses explicit and implicit setup mechanisms to request resources from the network for the purpose of supporting control plane functions and optimizing resource allocation.
Abstract--- For efficient resource allocation, the resource and mobility management schemes have been coupled resulting in a QoS/Mobility aware network architecture able to react proactively to mobility events. Both management schemes have been optimized to work together, in order to support seamless handovers for mobile users running real-time applications.
Abstract--- The analysis of performance improvement and the model parametrization of the proposed solution have been evaluated using simulation. Simulation results show that the solution avoids network congestion and also the starvation of less priority DiffServ classes. Moreover, the results also show that bandwidth utilization for priority classes is levered and that the QoS offered to Mobile Node's (MN's) applications, within each DiffServ class, is maintained in spite of MN mobility.
Abstract--- The proposed model is simple, easy to implement and takes into account the mobile Internet requirements. Simulation results show that this new methodology is effective and able to provide QoS services adapted to application requests
QoS-aware architecture for FHMIP micromobility
Wireless networks will certainly run applications with strict QoS requirements and so, micro-mobility protocols such as fast hierarchical mobile IPv6 (FHMIP) are useful tools to accomplish this new feature. The FHMIP is an effective scheme to reduce Mobile IPv6 handover disruption, however it does not support application's QoS requirements. Therefore, in order to provide QoS guarantees for real-time applications it is necessary to develop new traffic management schemes; this implies the optimization of network mobility support and also some network congestion control. A traffic management scheme of this type should take into account the QoS requirements of handover users and should implement a resource management (RM) scheme in order to achieve this. In this paper, a new RM scheme for the DiffServ QoS model is proposed. This new scheme is implemented by access routers as an extension to FHMIP micromobility protocol. In order to prevent QoS degradation of the existing traffic, access routers should evaluate the impact of admitting a new mobile node (MN), previously to the handover. This evaluation and sequent decision on wether admitting or refusing MN's traffic is based on a measurement-based admission control (MBAC) algorithm. This architecture, that has been implemented and tested using ns-2, includes a simple signaling protocol, a traffic descriptor and exhibits an adaptive behavior to traffic QoS requirements. All the necessary measurements are aggregated by class-of-service, thus avoiding maintaining state on the individual flows.(undefined
Evaluating rate-estimation for a mobility and QoS-aware network architecture
In a nearby future wireless networks will run applications with special QoS requirements. FHMIP is an effective scheme to reduce Mobile IPv6 handover disruption but it does not deal with any other specific QoS requirement. Therefore new traffic management schemes are needed in order to provide QoS guarantees to real-time applications and this implies network mobility optimizations and congestion control support. Traffic management schemes should deal with QoS requirements during handover and should use some resource management strategy in order to achieve this. In this article a new resource management scheme for DiffServ QoS model is proposed, to be used by access routers as an extension to FHMIP micromobility protocol. In order to prevent QoS deterioration, access routers pre-evaluate the impact of accepting all traffic from a mobile node, previous to the handover. This pre-evaluation and post decision on whether or not to accept any, or all, of this new traffic is based on a measurement based admission control procedure. This mobility and QoS-aware network architecture, integrating a simple signaling protocol, a traffic descriptor, and exhibiting adaptive behavior has been implemented and tested using ns-2. All measurements and decisions are based on DiffServ class-of-service aggregations, thus avoiding large flow state information maintenance. Rate estimators are essential mechanisms to the efficiency of this QoS-aware overall architecture. Therefore, in order to be able to choose the rate estimator that better fits this global architecture, two rate estimators - Time Sliding Window (TSW) and Exponential Moving Average (EMA) - have been studied and evaluated by means of ns-2 simulations in QoS-aware wireless mobility scenarios.Nuno V. Lopes was supported by an FCT Grant (SFRH/BD/35245/2007
A micro-mobility solution for supporting QoS in global mobility
Today, users want to have simultaneously mobility, Quality of Service (QoS) and be always connected to Internet. Therefore, this paper proposes a QoS micro-mobility solution able to provide QoS support for global mobility. The solution comprises enhancements in the mobility management of Mobile IPv6 (MIPv6) and in the resources management of Differentiated Services (DiffServ) QoS model. The mobility management of MIPv6 was extended with fast and local handovers to improve its efficiency in micro-mobility scenarios with frequent handovers. The DiffServ resource management has been extended with adaptive and dynamic QoS provisioning to improve resources utilization in mobile IP networks. Further, in order to improve resources utilization the mobility and QoS messages were coupled, providing a resource management able to, proactively, react to mobile events. The performance improvement of the proposed solution and the model parametrization was evaluated using a simulation model. Simulation results indicate that the solution avoids network congestion and starvation of less priority DiffServ classes. Moreover, the results also indicate that bandwidth utilization for priority classes increases and the QoS offered to MN's applications, in each DiffServ class, keeps up unchangeable with MN mobility.(undefined
Efficiency of PRI and WRR DiffServ scheduling mechanisms for real-time services on UMTS environment
The next generation of mobile phones will be probably all-IP based enabling users to access Internet services. In order to make this possible a satisfactory quality of service, at least equal to the fixed Internet, must be ensured. To achieve this goal an end-to-end QoS system must be constructed. Another fact is the dominance of IP over other technologies due, in large measure, to its characteristic of working with heterogeneous technologies. Consequently, being IP the common denominator on a heterogeneous environment, it is important to develop end-to-end IP QoS guarantees for the different applications over distinct access technologies. This is particularly important for cellular wireless networks due to the ever growing expansion of mobile phone users. One way to contribute to this goal is to apply DiffServ QoS mechanisms to UMTS technology in order to model an End-to-End QoS communication system. A mapping of DiffServ CodePoints into UMTS classes can be applied in order to get efficient PHB configurations. This paper proposes an architecture to support end-to-end quality of service to several application services running on mobile UMTS user agents and communicating with servers located in a wired internet. The proposed architecture is based on a DiffServ model, where QoS parameters are set either by the user agent or by the SGSN. In particular, RED queue management and PRI or WRR scheduling policies are enforced. Different UMTS traffic classes are mapped into different DiffServ parameters. The performance of this architecture has been evaluated by simulation using NS, assuming different network load scenarios. In particular, the delay and packet loss experienced by VoIP, Video, FTP and HTTP traffic are evaluated in the cases of PRI and WRR scheduling policies, and compared to those measured when DiffServ is not implemented. Finally, a revenue function to estimate the profits that an ISP could expect by using a DiffServ implementation on IP UMTS core routers is proposed.(undefined
Performance analysis of a new mobility/QoS-aware architecture
Ideally, the future Internet must provide acceptable Quality of Service (QoS) to mobile users that are running real-time applications and are moving across different access points at high speeds. The user mobility presents a great challenge to the network layer in order to maintain users on going connections. Currently, the Internet protocol that manages the user mobility at the network level is the Mobile Internet Protocol (MIP). This protocol, when a mobile user changes its point of attachment, maintains the same IP address for mobile node, so that user mobility became invisible to the application level and thus avoiding a connection interruption. Although, MIP standard allows the user mobility while maintaining an uninterrupted connection to an application, it does not have any concerns with the QoS support provided to applications with more strict performance requirements such as real-time applications. This paper addresses the issue of mobility and QoS management principles as well as the mobility and QoS management integration in the sense of build a QoS-aware architecture for mobile Internet. After covering the mobility and QoS management principles and integration, this paper also proposes a new QoS-aware architecture for mobile Internet. This new architecture takes into account the specific characteristics of mobile networks in order to design an integrated Mobility/QoS-aware management architecture suitable for real-time applications requirements. The simulation results indicate that the suggested architecture is able to provide acceptable QoS levels to real-time applications that are running in mobiles devices.(undefined