3,508 research outputs found

    DSTP-AN: A Distributed System for Transaction Processing Based on Data Resource Migration in ATM Networks

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    The dynamic migration of data resources has become a strong tool for transaction processing in broadband networks such as ATM. In this paper, a distributed system that takes advantage of data resource migration for transaction processing in ATM networks has been proposed. The proposed system provides mechanisms to select the transaction processing method, to migrate data resources in a way that reduces the time delay and message traffic in locating and accessing them. The first mechanism selects one of the two transaction processing methods: the traditional method that uses two phase commit protocol and other new method based on data resource migration. The second mechanism attempts to improve performance by making each site follow a local policy for directing requests to locate and access data resources as well as migrating them through the system. For this, a new scheme that focuses on reducing the time delay and message traffic needed to access the migratory data resources is proposed. The performance of the proposed scheme has also been evaluated and compared with one of the existing schemes by a simulation study under different system parameters such as frequency of access to the data resources, frequency of data resource migrations, scale of network, etc

    An optimal data service providing framework in cloud radio access network

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    Much work has been conducted to design effective and efficient algorithms for quality of service (QoS)-aware service computing in the past several years. The wireless mobile computing and cloud computing environments have brought many challenges to QoS-aware service providing. Mobile cloud computing (MCC) and cloud radio accessing networks (C-RANs) are the new paradigms arising in recent years. This work proposes a wireless data service providing framework in C-RAN aiming to provide data service in C-RAN by a more efficient way. The efficiency is measured by cost with time constraint. An abstract formal model is built on the proposed framework, and the corresponding optimal solution is deduced theoretically using queuing theory and convex optimization. The simulation results show that the proposed optimal strategy on the optimal solution works well and has a better performance than compared one

    Smartphone-based crowdsourcing for estimating the bottleneck capacity in wireless networks

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    Crowdsourcing enables the fine-grained characterization and performance evaluation of today׳s large-scale networks using the power of the masses and distributed intelligence. This paper presents SmartProbe, a system that assesses the bottleneck capacity of Internet paths using smartphones, from a mobile crowdsourcing perspective. With SmartProbe measurement activities are more bandwidth efficient compared to similar systems, and a larger number of users can be supported. An application based on SmartProbe is also presented: georeferenced measurements are mapped and used to compare the performance of mobile broadband operators in wide areas. Results from one year of operation are included

    Network emulation focusing on QoS-Oriented satellite communication

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    This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication

    Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey

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    Wireless sensor networks (WSNs) consist of autonomous and resource-limited devices. The devices cooperate to monitor one or more physical phenomena within an area of interest. WSNs operate as stochastic systems because of randomness in the monitored environments. For long service time and low maintenance cost, WSNs require adaptive and robust methods to address data exchange, topology formulation, resource and power optimization, sensing coverage and object detection, and security challenges. In these problems, sensor nodes are to make optimized decisions from a set of accessible strategies to achieve design goals. This survey reviews numerous applications of the Markov decision process (MDP) framework, a powerful decision-making tool to develop adaptive algorithms and protocols for WSNs. Furthermore, various solution methods are discussed and compared to serve as a guide for using MDPs in WSNs

    Aika: A Distributed Edge System For Machine Learning Inference. Detecting and defending against abnormal behavior in untrusted edge environments

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    The edge computing paradigm has recently started to gain a lot of momentum. The field of Artificial Intelligence (AI) has also grown in recent years, and there is currently ongoing research that investigates how AI can be applied to numerous of different fields. This includes the edge computing domain. In Norway, there is currently ongoing research being conducted that investigates how the confluence between AI and edge computing can be used to hinder fish crime, by stationing surveillance equipment aboard fishing vessels, and perform all the monitoring directly on the vessel with support of AI. This is challenging for several reasons. First and foremost, the equipment needs to be stationed on the vessel, where actors may impose a threat to it and attempt to damage it, or interfere with the analytical process. The second challenge is to enable multiple machine learning pipelines to be executed effectively on the equipment. This requires a versatile computation model, where data is handled in a privacy preserving manner. This thesis presents Áika, a distributed edge computing system that supports machine learning inference in such untrusted edge environments. Áika is designed as a hierarchical fault tolerant system that supports a directed acyclic graph (DAG) computation model for executing machine inference on the edge, where a monitor residing in a trusted location can ensure that the system is running as expected. The experiment results demonstrate that Áika can tolerate failures while remaining operable with a stable throughput, although this will depend on the specific configuration and what computations that are implemented. The results also demonstrate that Áika can be used for both simple tasks, like counting words in a textual document, and for more complex tasks, like performing feature extraction using pre-trained deep learning models that are distributed across different workers. With Áika, application developers can develop fault tolerant and different distributed DAGs composed of multiple pipelines
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