1,494 research outputs found

    Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections

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    Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay networ

    An Experimental Evaluation of the Computational Cost of a DPI Traffic Classifier

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    A common belief in the scientific community is that traffic classifiers based on deep packet inspection (DPI) are far more expensive in terms of computational complexity compared to statistical classifiers. In this paper we counter this notion by defining accurate models for a deep packet inspection classifier and a statistical one based on support vector machines, and by evaluating their actual processing costs through experimental analysis. The results suggest that, contrary to the common belief, a DPI classifier and an SVM-based one can have comparable computational costs. Although much work is left to prove that our results apply in more general cases, this preliminary analysis is a first indication of how DPI classifiers might not be as computationally complex, compared to other approaches, as we previously though

    Phosphorus, Sulphur and Micronutrients on Grassland Improvement with White Clover (\u3ci\u3eTrifolium repens\u3c/i\u3e L.) on Basaltic Soils in Uruguay

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    Grasslands improvement with legumes is a promising technology for increasing forage quality and productivity on basaltic soils, but requires the correction of nutrient deficiencies. Phosphorus is a key element, but usual techniques of soil analysis are not good predictors. An experimental work was conducted in the northern region of the country. Evaluating the response of an improvement with white clover to P. Citric Acid showed a good association between soil P status and legume behavior. In addition there was a positive trend in forage production, in relation to S application, even though this effect was only significant in legume yield during the second year. Neither Mo nor B resulted in significant effects on forage yield. Results should be considered as preliminary, due to climatic problems that limited the experimental work

    CrownLabs - A Collaborative Environment to Deliver Remote Computing Laboratories

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    The coronavirus pandemic hit the entire education sector hard. All students were sent home and lectures started to be delivered through video-conferencing systems. CrownLabs is an open-source project providing an answer to the problem of delivering remote computing laboratories. Simplicity is one of its main characteristics, requiring nothing but a simple web browser to interact with the system and being all heavyweight computations performed at the university premises. Cooperation and mentoring are also encouraged through parallel access to the same remote desktop. The entire system is built up using components from the Kubernetes ecosystem, to replicate a "cloud grade" infrastructure, coupled with custom software implementing the core business logic. To this end, most of the complexity has been delegated to the infrastructure, to speed up the development process and reduce the maintenance burden. An extensive evaluation has been performed in both real and simulated scenarios to validate the overall performance: the results are encouraging, as well as the feedback from the early adopters of the system

    Comparing P2PTV Traffic Classifiers

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    Peer-to-Peer IP Television (P2PTV) applications represent one of the fastest growing application classes on the Internet, both in terms of their popularity and in terms of the amount of traffic they generate. While network operators require monitoring tools that can effectively analyze the traffic produced by these systems, few techniques have been tested on these mostly closed-source, proprietary applications. In this paper we examine the properties of three traffic classifiers applied to the problem of identifying P2PTV traffic. We report on extensive experiments conducted on traffic traces with reliable ground truth information, highlighting the benefits and shortcomings of each approach. The results show that not only their performance in terms of accuracy can vary significantly, but also that their usability features suggest different effective aspects that can be integrate

    Simplified evaluation of energetic complementarity based on monthly average data

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    Energetic complementarity is a subject that has been holding more and more attention from researchers in recent years, being a concept that can be applied both in energy planning stages and in phases of operation of energy systems based on renewable energy resources. The complementarity between two renewable sources of energy has three components: time-complementarity, energy-complementarity and amplitude-complementarity, and can be determined between raw energy availabilities or between energy generated by power plants. Complementarity can be evaluated between two renewable resources in the same place or between two renewable resources in different places and these two types can be denominated respectively as temporal and spatial complementarity. This method allows simplified evaluation of the energy complementarity between two renewable resources by comparing basic parameters obtained from series of monthly average values that characterize these resources. Finally, an application example clarifies the application of the method
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