UPCommons
http://upcommons.upc.edu
UPCommons, the website that provides open access to the knowledge of UPC, is formed by the group of open institutional repositories of UPC and its aim is to guarantee the safeguarding of the material produced by lecturers and researchers at the University, to maximise that material’s visibility and, consequently, to increase its impact on education and research worldwide.2016-08-25T18:37:32ZNumerical implementation and computational results of nonlinear network optimization with linear side constraints
http://hdl.handle.net/2117/89385
Numerical implementation and computational results of nonlinear network optimization with linear side constraints
Heredia, F.-Javier (Francisco Javier); Nabona Francisco, Narcís
2016-08-25T13:03:53ZHeredia, F.-Javier (Francisco Javier)Nabona Francisco, NarcísDynamic modeling and controllability analysis of an ethanol reformer for fuel cell application
http://hdl.handle.net/2117/89384
Dynamic modeling and controllability analysis of an ethanol reformer for fuel cell application
García, Vanesa Mariel; Lopez Null, Eduardo; Serra, Maria; Llorca Piqué, Jordi; Riera Colomer, Jordi
This work presents a controllability analysis of a low temperature ethanol reformer based on a cobalt catalyst for fuel cell application. The study is based on a nonlinear dynamic model of a reformer which operates in three separate stages: ethanol dehydrogenation to acetaldehyde and hydrogen, acetaldehyde steam reforming, and water gas shift reaction. The controllability anal
ysis is focused on the rapid dynamics due to mass balances and is based on a linear
ization of the complex non-linear model of the reformer. RGA, CN and MRI analysis tools are applied to the linear model suggesting that a good performance can be
obtained with decentralized control for frequencies up to 0.1 rad/s.
2016-08-24T12:41:35ZGarcía, Vanesa MarielLopez Null, EduardoSerra, MariaLlorca Piqué, JordiRiera Colomer, JordiThis work presents a controllability analysis of a low temperature ethanol reformer based on a cobalt catalyst for fuel cell application. The study is based on a nonlinear dynamic model of a reformer which operates in three separate stages: ethanol dehydrogenation to acetaldehyde and hydrogen, acetaldehyde steam reforming, and water gas shift reaction. The controllability anal
ysis is focused on the rapid dynamics due to mass balances and is based on a linear
ization of the complex non-linear model of the reformer. RGA, CN and MRI analysis tools are applied to the linear model suggesting that a good performance can be
obtained with decentralized control for frequencies up to 0.1 rad/s.Exact interval propagation for the efficient solution of position analysis problems on planar linkages
http://hdl.handle.net/2117/89383
Exact interval propagation for the efficient solution of position analysis problems on planar linkages
Celaya Llover, Enric; Creemers, Tom Lambert; Ros Giralt, Lluís
This paper presents an interval propagation algorithm for variables in planar single-loop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, with out over-estimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branch-and-prune search scheme, in order to solve the position analysis of general planar multi-loop linkages. Experimental results are included, comparing the method’s perfor mance with that of previous techniques given for the same task.
2016-08-24T10:56:12ZCelaya Llover, EnricCreemers, Tom LambertRos Giralt, LluísThis paper presents an interval propagation algorithm for variables in planar single-loop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, with out over-estimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branch-and-prune search scheme, in order to solve the position analysis of general planar multi-loop linkages. Experimental results are included, comparing the method’s perfor mance with that of previous techniques given for the same task.Stock management in hospital pharmacy using chance-constrained model predictive control
http://hdl.handle.net/2117/89382
Stock management in hospital pharmacy using chance-constrained model predictive control
Jurado, Isabel; Maestre Torreblanca, José María; Velarde, Pablo; Ocampo-Martínez, Carlos; Fernandez, Isabel; Isla Tejera, Beatriz; del Prado, José Ramón
One of the most important problems in the pharmacy department of a hospital is stock management. The clinical needs of drugs must be satisfied with limited work labor while minimizing the use of economical resources. The complexity of the problem resides in the random nature of the drug demand and the multiple constraints that must be taken into account in every decision. In this article, chance-constrained model predictive control is proposed to deal with this problem. The flexibility of model predictive control allows taking into account explicitly the different objectives and constraints involved in the problem while the use of chance constraints provides a trade-off between conservativeness and efficiency. The solution proposed is assessed to study its implementation in two Spanish hospitals
2016-08-24T10:09:12ZJurado, IsabelMaestre Torreblanca, José MaríaVelarde, PabloOcampo-Martínez, CarlosFernandez, IsabelIsla Tejera, Beatrizdel Prado, José RamónOne of the most important problems in the pharmacy department of a hospital is stock management. The clinical needs of drugs must be satisfied with limited work labor while minimizing the use of economical resources. The complexity of the problem resides in the random nature of the drug demand and the multiple constraints that must be taken into account in every decision. In this article, chance-constrained model predictive control is proposed to deal with this problem. The flexibility of model predictive control allows taking into account explicitly the different objectives and constraints involved in the problem while the use of chance constraints provides a trade-off between conservativeness and efficiency. The solution proposed is assessed to study its implementation in two Spanish hospitalsOptimal location of fast charging stations in Barcelona: a flow-capturing approach
http://hdl.handle.net/2117/89381
Optimal location of fast charging stations in Barcelona: a flow-capturing approach
Cruz Zambrano, Miguel; Corchero García, Cristina; Igualada González, Lucía; Bernardo, Valeria
The aim of this paper is to find the optimal location of electric vehicle (EV) fast charging stations by means of two methodologies: a classical flow-capturing optimization model involving only mobility needs, and an advanced flow-capturing optimization model including distribution network and location costs. While the first model aims to maximize the public service provided by the fast charging stations, the second also considers the incurred cost for providing it. Results from both models are compared in order to analyse the effect of both planning approaches in total cost of installation. As a case study it has been chosen the city of Barcelona.
2016-08-24T08:57:52ZCruz Zambrano, MiguelCorchero García, CristinaIgualada González, LucíaBernardo, ValeriaThe aim of this paper is to find the optimal location of electric vehicle (EV) fast charging stations by means of two methodologies: a classical flow-capturing optimization model involving only mobility needs, and an advanced flow-capturing optimization model including distribution network and location costs. While the first model aims to maximize the public service provided by the fast charging stations, the second also considers the incurred cost for providing it. Results from both models are compared in order to analyse the effect of both planning approaches in total cost of installation. As a case study it has been chosen the city of Barcelona.IOStack: Software-Defined Object Storage
http://hdl.handle.net/2117/89380
IOStack: Software-Defined Object Storage
Gracia-Tinedo, Raúl; García-López, Pedro; Sánchez-Artigas, Marc; Sampé, Josep; Moatti, Yosef; Rom, Eran; Naor, Dalit; Nou, Ramon; Cortés, Toni; Oppermann, William; Michiardi, Pietro
The complexity and scale of today’s cloud storage systems is growing fast. In response to these challenges, Software-
Defined Storage (SDS) has recently become a prime candidate to simplify storage management in the cloud.
This article presents IOStack: The first SDS architecture for object stores (OpenStack Swift). At the control plane,
the provisioning of SDS services to tenants is made according to a set of policies managed via a high-level DSL. Policies may target storage automation and/or specific SLA objectives. At the data plane, policies define the enforcement of SDS services, namely filters, on a tenant’s requests. Moreover, IOStack is a framework to build a variety of filters, ranging from general-purpose computations close to the data to specialized data management mechanisms.
Our experiments illustrate that IOStack enables easy and effective policy-based provisioning, which can significantly
improve the operation of a multi-tenant object store.
2016-08-23T12:38:24ZGracia-Tinedo, RaúlGarcía-López, PedroSánchez-Artigas, MarcSampé, JosepMoatti, YosefRom, EranNaor, DalitNou, RamonCortés, ToniOppermann, WilliamMichiardi, PietroThe complexity and scale of today’s cloud storage systems is growing fast. In response to these challenges, Software-
Defined Storage (SDS) has recently become a prime candidate to simplify storage management in the cloud.
This article presents IOStack: The first SDS architecture for object stores (OpenStack Swift). At the control plane,
the provisioning of SDS services to tenants is made according to a set of policies managed via a high-level DSL. Policies may target storage automation and/or specific SLA objectives. At the data plane, policies define the enforcement of SDS services, namely filters, on a tenant’s requests. Moreover, IOStack is a framework to build a variety of filters, ranging from general-purpose computations close to the data to specialized data management mechanisms.
Our experiments illustrate that IOStack enables easy and effective policy-based provisioning, which can significantly
improve the operation of a multi-tenant object store.A bilevel programming formulation for modelling the location of information: points for traffic conditions
http://hdl.handle.net/2117/89379
A bilevel programming formulation for modelling the location of information: points for traffic conditions
Montero Mercadé, Lídia; Codina Sancho, Esteve; Marín, Angel
2016-08-23T11:36:25ZMontero Mercadé, LídiaCodina Sancho, EsteveMarín, AngelExploring interconnect energy savings under East-West traffic pattern of MapReduce clusters
http://hdl.handle.net/2117/89378
Exploring interconnect energy savings under East-West traffic pattern of MapReduce clusters
Fischer e Silva, Renan; Carpenter, Paul M.
An important challenge of modern data centers is to reduce energy consumption, of which a substantial proportion is due to the network. Energy Efficient Ethernet (EEE) is a recent standard that aims to reduce network power consumption, but current practice is to disable it in production use, since it has a poorly understood impact on real world application performance. An important application framework commonly used in modern data centers is Apache Hadoop, which implements the MapReduce programming model. This paper is the first to analyse the impact of EEE on MapReduce workloads, in terms of performance overheads and energy savings. We find that optimum energy savings are possible if the links use
packet coalescing. Packet coalescing must, however, be carefully configured in order to avoid excessive performance degradation.
2016-08-19T12:50:31ZFischer e Silva, RenanCarpenter, Paul M.An important challenge of modern data centers is to reduce energy consumption, of which a substantial proportion is due to the network. Energy Efficient Ethernet (EEE) is a recent standard that aims to reduce network power consumption, but current practice is to disable it in production use, since it has a poorly understood impact on real world application performance. An important application framework commonly used in modern data centers is Apache Hadoop, which implements the MapReduce programming model. This paper is the first to analyse the impact of EEE on MapReduce workloads, in terms of performance overheads and energy savings. We find that optimum energy savings are possible if the links use
packet coalescing. Packet coalescing must, however, be carefully configured in order to avoid excessive performance degradation.Impact of WRF model PBL schemes on air quality simulations over Catalonia, Spain
http://hdl.handle.net/2117/89377
Impact of WRF model PBL schemes on air quality simulations over Catalonia, Spain
Banks, Robert F.; Baldasano, Jose M.
Here we analyze the impact of four planetary boundary-layer (PBL) parametrization schemes from the Weather Research and Forecasting (WRF) numerical weather prediction model on simulations of meteorological variables and predicted pollutant concentrations from an air quality forecast system (AQFS). The current setup of the Spanish operational AQFS, CALIOPE, is composed of the WRF-ARW V3.5.1 meteorological model tied to the Yonsei University (YSU) PBL scheme, HERMES v2 emissions model, CMAQ V5.0.2 chemical transport model, and dust outputs from BSC-DREAM8bv2. We test the performance of the YSU scheme against the Assymetric Convective Model Version 2 (ACM2), Mellor-Yamada-Janjic (MYJ), and Bougeault-Lacarrère (BouLac) schemes. The one-day diagnostic case study is selected to represent the most frequent synoptic condition in the northeast Iberian Peninsula during spring 2015; regional recirculations. It is shown that the ACM2 PBL scheme performs well with daytime PBL height, as validated against estimates retrieved using a micro-pulse lidar system (mean bias = − 0.11 km). In turn, the BouLac scheme showed WRF-simulated air and dew point temperature closer to METAR surface meteorological observations. Results are more ambiguous when simulated pollutant concentrations from CMAQ are validated against network urban, suburban, and rural background stations. The ACM2 scheme showed the lowest mean bias (− 0.96 μg m− 3) with respect to surface ozone at urban stations, while the YSU scheme performed best with simulated nitrogen dioxide (− 6.48 μg m− 3). The poorest results were with simulated particulate matter, with similar results found with all schemes tested.
2016-08-11T09:35:21ZBanks, Robert F.Baldasano, Jose M.Here we analyze the impact of four planetary boundary-layer (PBL) parametrization schemes from the Weather Research and Forecasting (WRF) numerical weather prediction model on simulations of meteorological variables and predicted pollutant concentrations from an air quality forecast system (AQFS). The current setup of the Spanish operational AQFS, CALIOPE, is composed of the WRF-ARW V3.5.1 meteorological model tied to the Yonsei University (YSU) PBL scheme, HERMES v2 emissions model, CMAQ V5.0.2 chemical transport model, and dust outputs from BSC-DREAM8bv2. We test the performance of the YSU scheme against the Assymetric Convective Model Version 2 (ACM2), Mellor-Yamada-Janjic (MYJ), and Bougeault-Lacarrère (BouLac) schemes. The one-day diagnostic case study is selected to represent the most frequent synoptic condition in the northeast Iberian Peninsula during spring 2015; regional recirculations. It is shown that the ACM2 PBL scheme performs well with daytime PBL height, as validated against estimates retrieved using a micro-pulse lidar system (mean bias = − 0.11 km). In turn, the BouLac scheme showed WRF-simulated air and dew point temperature closer to METAR surface meteorological observations. Results are more ambiguous when simulated pollutant concentrations from CMAQ are validated against network urban, suburban, and rural background stations. The ACM2 scheme showed the lowest mean bias (− 0.96 μg m− 3) with respect to surface ozone at urban stations, while the YSU scheme performed best with simulated nitrogen dioxide (− 6.48 μg m− 3). The poorest results were with simulated particulate matter, with similar results found with all schemes tested.How experiments and molecular simulations can help understand selective C25-hydroxylation of vitamin D by fungal peroxygenases
http://hdl.handle.net/2117/89376
How experiments and molecular simulations can help understand selective C25-hydroxylation of vitamin D by fungal peroxygenases
Lucas, Fatima; Babot, Esteban D.; Cañellas, Marina; del Río, José C.; Kalum, Lisbeth; Ullrich, René; Hofrichter, Martin; Martínez, Angel T.; Gutiérrez, Ana
2016-08-09T12:39:58ZLucas, FatimaBabot, Esteban D.Cañellas, Marinadel Río, José C.Kalum, LisbethUllrich, RenéHofrichter, MartinMartínez, Angel T.Gutiérrez, Ana