Search

[EN] This paper presents the potential of open source software for designing educational tools in the automatization field. In particular, this paper presents a complete tool that students can use for studying and testing nonlinear control algorithms. The system has three different parts that students can evaluate and modify. Firstly, a virtual model represents the physical model and, in this case, an inverted pendulum is used. Secondly, the controller is implemented by a real-time distributed control system. Finally, the system can be managed with a JAVA application. Therefore, students have all the necessary elements to practice using nonlinear and complex systems. The main tools applied in the design are open source software and the developed platform is Generalized Public License(GPL). © 2009 Wiley Periodicals, Inc.

[EN] This paper presents the potential of open source software for designing educational tools in the automatization field. In particular, this paper presents a complete tool that students can use for studying and testing nonlinear control algorithms. The system has three different parts that students can evaluate and modify. Firstly, a virtual model represents the physical model and, in this case, an inverted pendulum is used. Secondly, the controller is implemented by a real-time distributed control system. Finally, the system can be managed with a JAVA application. Therefore, students have all the necessary elements to practice using nonlinear and complex systems. The main tools applied in the design are open source software and the developed platform is Generalized Public License(GPL). © 2009 Wiley Periodicals, Inc.

European river basin authorities are responsible for the implementation of the new river basin management plans in accordance with the European Water Framework Directive. This paper presents a new methodology framework and approach to define and evaluate environmental flow regimes in the realistic complexities that exist with multiple water resource needs at a basin scale. This approach links river basin simulation models and habitat time series analysis to generate ranges of environmental flows (e-flows), which are evaluated by using habitat, hydropower production and reliability of water supply criteria to produce best possible alternatives. With the use of these tools, the effects of the proposed e-flows have been assessed to help in the consultation process. The possible effects analysed are impacts on water supply reliability, hydropower production and aquatic habitat. After public agreements, a heuristic optimization process was applied to maximize e-flows and habitat indicators, while maintaining a legal level of reliability for water resource demands. The final optimal e-flows were considered for the river basin management plans of the Duero river basin. This paper demonstrates the importance of considering quantitative hydrologic and ecological aspects of e-flows at the basin scale in addressing complex water resource systems. This approach merges standard methods such as physical habitat simulations and time series analyses for evaluating alternatives, with recent methods to simulate and optimize water management alternatives in river networks. It can be integrated with or used to complement other frameworks for e-flow assessments such as the In-stream Flow Incremental Methodology and Ecological Limits of Hydrologic Alteration.

The fat-tree is one of the most common topologies among the interconnection networks of the systems currently used for high-performance parallel computing. Among other advantages, fat-trees allow the use of simple but very efficient routing schemes. One of them is a deterministic routing algorithm that has been recently proposed, offering a similar (or better) performance than adaptive routing while reducing complexity and guaranteeing in-order packet delivery. However, as other deterministic routing proposals, this deterministic routing algorithm cannot react when high traffic loads or hot-spot traffic scenarios produce severe contention for the use of network resources, leading to the appearance of Head-of-Line (HoL) blocking, which spoils the network performance. In that sense, we describe in this paper two simple, cost-effective strategies for dealing with the HoL-blocking problem that may appear in fat-trees with the aforementioned deterministic routing algorithm. From the results presented in the paper, we conclude that, in the mentioned environment, these proposals considerably reduce HoL-blocking without significantly increasing switch complexity and the required silicon area.

European river basin authorities are responsible for the implementation of the new river basin management plans in accordance with the European Water Framework Directive. This paper presents a new methodology framework and approach to define and evaluate environmental flow regimes in the realistic complexities that exist with multiple water resource needs at a basin scale. This approach links river basin simulation models and habitat time series analysis to generate ranges of environmental flows (e-flows), which are evaluated by using habitat, hydropower production and reliability of water supply criteria to produce best possible alternatives. With the use of these tools, the effects of the proposed e-flows have been assessed to help in the consultation process. The possible effects analysed are impacts on water supply reliability, hydropower production and aquatic habitat. After public agreements, a heuristic optimization process was applied to maximize e-flows and habitat indicators, while maintaining a legal level of reliability for water resource demands. The final optimal e-flows were considered for the river basin management plans of the Duero river basin. This paper demonstrates the importance of considering quantitative hydrologic and ecological aspects of e-flows at the basin scale in addressing complex water resource systems. This approach merges standard methods such as physical habitat simulations and time series analyses for evaluating alternatives, with recent methods to simulate and optimize water management alternatives in river networks. It can be integrated with or used to complement other frameworks for e-flow assessments such as the In-stream Flow Incremental Methodology and Ecological Limits of Hydrologic Alteration.

The fat-tree is one of the most common topologies among the interconnection networks of the systems currently used for high-performance parallel computing. Among other advantages, fat-trees allow the use of simple but very efficient routing schemes. One of them is a deterministic routing algorithm that has been recently proposed, offering a similar (or better) performance than adaptive routing while reducing complexity and guaranteeing in-order packet delivery. However, as other deterministic routing proposals, this deterministic routing algorithm cannot react when high traffic loads or hot-spot traffic scenarios produce severe contention for the use of network resources, leading to the appearance of Head-of-Line (HoL) blocking, which spoils the network performance. In that sense, we describe in this paper two simple, cost-effective strategies for dealing with the HoL-blocking problem that may appear in fat-trees with the aforementioned deterministic routing algorithm. From the results presented in the paper, we conclude that, in the mentioned environment, these proposals considerably reduce HoL-blocking without significantly increasing switch complexity and the required silicon area.

Video streaming services have restrictive delay and bandwidth constraints. Ad hoc networks represent a hostile environment for this kind of real-time data transmission. Emerging mesh networks, where a backbone provides more topological stability, do not even assure a high quality of experience. In such scenario, mobility of terminal nodes causes link breakages until a new route is calculated. In the meanwhile, lost packets cause annoying video interruptions to the receiver. This paper proposes a new mechanism of recovering lost packets by means of caching overheard packets in neighbor nodes and retransmit them to destination. Moreover, an optimization is shown, which involves a video-aware cache in order to recover full frames and prioritize more significant frames. Results show the improvement in reception, increasing the throughput as well as video quality, whereas larger video interruptions are considerably reduced. Copyright © 2014 John Wiley & Sons, Ltd.

Video streaming services have restrictive delay and bandwidth constraints. Ad hoc networks represent a hostile environment for this kind of real-time data transmission. Emerging mesh networks, where a backbone provides more topological stability, do not even assure a high quality of experience. In such scenario, mobility of terminal nodes causes link breakages until a new route is calculated. In the meanwhile, lost packets cause annoying video interruptions to the receiver. This paper proposes a new mechanism of recovering lost packets by means of caching overheard packets in neighbor nodes and retransmit them to destination. Moreover, an optimization is shown, which involves a video-aware cache in order to recover full frames and prioritize more significant frames. Results show the improvement in reception, increasing the throughput as well as video quality, whereas larger video interruptions are considerably reduced. Copyright © 2014 John Wiley & Sons, Ltd.

This paper presents the results of an experimental research dealing with bond strength as a parameter for concrete quality control. To this end, a low-cost testing technique has been developed: the Bottle Bond Test (BBT). Specimens for the BBT are produced by casting concrete into empty plastic bottles (used as moulds) with a reinforcing bar longitudinally centred. The result is a bottle-shaped concrete specimen with an embedded rebar, which is pulled out to determine bond strength. Different parameters related to this test setup modify bond strength: their effect has been analyzed. An equation to relate the obtained bond strength values to concrete compressive strength is presented. This equation has been validated with real production data from a readymix concrete plant. Its accuracy and therefore the feasibility of BBT for concrete quality control have been verified. Therefore, the BBT can be an alternative to conventional concrete quality based on uniaxial compression tests.

This paper presents the results of an experimental research dealing with bond strength as a parameter for concrete quality control. To this end, a low-cost testing technique has been developed: the Bottle Bond Test (BBT). Specimens for the BBT are produced by casting concrete into empty plastic bottles (used as moulds) with a reinforcing bar longitudinally centred. The result is a bottle-shaped concrete specimen with an embedded rebar, which is pulled out to determine bond strength. Different parameters related to this test setup modify bond strength: their effect has been analyzed. An equation to relate the obtained bond strength values to concrete compressive strength is presented. This equation has been validated with real production data from a readymix concrete plant. Its accuracy and therefore the feasibility of BBT for concrete quality control have been verified. Therefore, the BBT can be an alternative to conventional concrete quality based on uniaxial compression tests.