214 research outputs found

    Performance evaluation of cooperation strategies for m-health services and applications

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    Health telematics are becoming a major improvement for patients’ lives, especially for disabled, elderly, and chronically ill people. Information and communication technologies have rapidly grown along with the mobile Internet concept of anywhere and anytime connection. In this context, Mobile Health (m-Health) proposes healthcare services delivering, overcoming geographical, temporal and even organizational barriers. Pervasive and m-Health services aim to respond several emerging problems in health services, including the increasing number of chronic diseases related to lifestyle, high costs in existing national health services, the need to empower patients and families to self-care and manage their own healthcare, and the need to provide direct access to health services, regardless the time and place. Mobile Health (m- Health) systems include the use of mobile devices and applications that interact with patients and caretakers. However, mobile devices have several constraints (such as, processor, energy, and storage resource limitations), affecting the quality of service and user experience. Architectures based on mobile devices and wireless communications presents several challenged issues and constraints, such as, battery and storage capacity, broadcast constraints, interferences, disconnections, noises, limited bandwidths, and network delays. In this sense, cooperation-based approaches are presented as a solution to solve such limitations, focusing on increasing network connectivity, communication rates, and reliability. Cooperation is an important research topic that has been growing in recent years. With the advent of wireless networks, several recent studies present cooperation mechanisms and algorithms as a solution to improve wireless networks performance. In the absence of a stable network infrastructure, mobile nodes cooperate with each other performing all networking functionalities. For example, it can support intermediate nodes forwarding packets between two distant nodes. This Thesis proposes a novel cooperation strategy for m-Health services and applications. This reputation-based scheme uses a Web-service to handle all the nodes reputation and networking permissions. Its main goal is to provide Internet services to mobile devices without network connectivity through cooperation with neighbor devices. Therefore resolving the above mentioned network problems and resulting in a major improvement for m-Health network architectures performances. A performance evaluation of this proposal through a real network scenario demonstrating and validating this cooperative scheme using a real m-Health application is presented. A cryptography solution for m-Health applications under cooperative environments, called DE4MHA, is also proposed and evaluated using the same real network scenario and the same m-Health application. Finally, this work proposes, a generalized cooperative application framework, called MobiCoop, that extends the incentive-based cooperative scheme for m-Health applications for all mobile applications. Its performance evaluation is also presented through a real network scenario demonstrating and validating MobiCoop using different mobile applications

    A Resilient and Energy-saving Incentive System for Resource Sharing in MANETs

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    Despite of all progress in terms of computational power, communication bandwidth, and feature richness, limited battery capacity is the major bottleneck for using the resources of mobile devices in innovative distributed applications. Incentives are required for motivating a user to spend energy on behalf of other users and it must be ensured that providing these incentives neither consumes much energy by itself nor allows for free-riding and other types of fraud. In this paper, we present a novel incentive system that is tailored to the application scenario of energyaware resource-sharing between mobile devices. The system has low energy consumption due to avoiding the use of public key cryptography. It uses a virtual currency with reusable coins and detects forgery and other fraud when cashing coins at an off-line broker. A prototype-based measurement study indicates the energy-efficiency of the system, while simulation studies show its resilience to fraud. Even in scenarios with 75% of fraudulent users that are colluding to disguise their fraud only 3.2% of them get away with it while the energy overhead (about 3%) for the incentive system is still moderat

    Hybrid FPMS: A New Fairness Protocol Management Scheme for Community Wireless Mesh Networks

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    Node cooperation during packet forwarding operations is critically important for fair resource utilization in Community Wireless Mesh Networks (CoWMNs). In a CoWMN, node cooperation is achieved by using fairness protocols specifically designed to detect and isolate malicious nodes, discourage unfair behavior, and encourage node participation in forwarding packets. In general, these protocols can be split into two groups: Incentive-based ones, which are managed centrally, and use credit allocation schemes. In contrast, reputation-based protocols that are decentralized, and rely on information exchange among neighboring nodes. Centrally managed protocols inevitably suffer from scalability problems. The decentralized, reputation-based protocols lacks in detection capability, suffer from false detections and error propagation compared to the centralized, incentive-based protocols. In this study, we present a new fairness protocol management scheme, called Hybrid FPMS that captures the superior detection capability of incentive-based fairness protocols without the scalability problems inherently expected from a centralized management scheme as a network's size and density grows. Simulation results show that Hybrid FPMS is more efficient than the current centralized approach and significantly reduces the network delays and overhead.Comment: KSII Transactions on Internet and Information Systems, 201

    Collaboration Enforcement In Mobile Ad Hoc Networks

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    Mobile Ad hoc NETworks (MANETs) have attracted great research interest in recent years. Among many issues, lack of motivation for participating nodes to collaborate forms a major obstacle to the adoption of MANETs. Many contemporary collaboration enforcement techniques employ reputation mechanisms for nodes to avoid and penalize malicious participants. Reputation information is propagated among participants and updated based on complicated trust relationships to thwart false accusation of benign nodes. The aforementioned strategy suffers from low scalability and is likely to be exploited by adversaries. To address these problems, we first propose a finite state model. With this technique, no reputation information is propagated in the network and malicious nodes cannot cause false penalty to benign hosts. Misbehaving node detection is performed on-demand; and malicious node punishment and avoidance are accomplished by only maintaining reputation information within neighboring nodes. This scheme, however, requires that each node equip with a tamper-proof hardware. In the second technique, no such restriction applies. Participating nodes classify their one-hop neighbors through direct observation and misbehaving nodes are penalized within their localities. Data packets are dynamically rerouted to circumvent selfish nodes. In both schemes, overall network performance is greatly enhanced. Our approach significantly simplifies the collaboration enforcement process, incurs low overhead, and is robust against various malicious behaviors. Simulation results based on different system configurations indicate that the proposed technique can significantly improve network performance with very low communication cost

    Policy-Based Immunization Framework for MANET

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    Mobility is one of the most important driving forces of hyper-interconnected world that we are living in. Mobile computing devices are becoming smaller, more ubiquitous and simultaneously providing more computing power. Various mobile devices in diff rent sizes with high computing power cause the emergence of new type of networks\u27 applications. Researchers in conferences, soldiers in battlefields, medics in rescue missions, and drivers in busy high- ways can perform more efficiently if they can be connected to each other and aware of the environment they are interacting with. In all mentioned scenarios, the major barrier to have an interconnected collaborative environment is the lack of infrastructure. Mobile Ad hoc Networks (MANETs) are very promising to be able to handle this challenge. In recent years, extensive research has been done on MANETs in order to deliver secure and reliable network services in an infrastructure-less environment. MANETs usually deal with dynamic network topologies and utilize wireless technologies, they are very susceptible to different security attacks targeting different network layers. Combining policy-based management concepts and trust evaluation techniques in more granular level than current trust management frameworks can lead to interesting results toward more secure and reliable MANETs
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