7,290 research outputs found
Impact of Coupling an Ocean Model to WRF Nor’easter Simulations
No full textThe impact of ocean–atmosphere coupling and its possible seasonal dependence upon Weather Research and Forecasting (WRF) Model simulations of seven, wintertime cyclone events was investigated. Model simulations were identical aside from the degree of ocean model coupling (static SSTs, 1D mixed layer model, full-physics 3D ocean model). Both 1D and 3D ocean model coupling simulations show that SSTs following the passage of a nor’easter did tend to cool more strongly during the early season (October–December) and were more likely to warm late in the season (February–April). Model simulations produce SST differences of up to 1.14 K, but this change did not lead to significant changes in storm track ( 1) and have low-to-moderate threat scores (0.31–0.59). Analysis of the storm environment and the overall simulation failed to reveal any statistically significant differences in model error attributable to ocean–atmosphere coupling. Despite this result, ocean model coupling can reduce dynamical field error at a single level by up to 20%, and this was slightly greater (1%–2%) with 3D ocean model coupling as compared to 1D ocean model coupling. Thus, while 3D ocean model coupling tended to generally produce more realistic simulations, its impact would likely be more profound for longer-term simulations.© Copyright 2015 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or [email protected] reviewe
Impact of coupling an ocean model to WRF nor’easter simulations
No full textThe impact of ocean-atmosphere coupling and its possible seasonal dependence upon Weather Research and Forecasting (WRF) model simulations of seven, winter-time cyclone events was investigated. Model simulations were identical aside from the degree of ocean model coupling (static SSTs, 1D mixed-layer model, full-physics 3D ocean model). Both 1D and 3D ocean model coupling simulations show that SSTs following the passage of a nor’easter did tend to cool more strongly during the early season (Oct-Dec) and were more likely to warm late in the season (Feb-Apr). Model simulations produce SST differences of up to 1.14 K, but this change did not lead to significant change in storm track ( 1) and have low-to-moderate threat scores (0.31 – 0.59). Analysis of the storm environment and the overall simulation failed to reveal any statistically significant differences in model error attributable to ocean-atmosphere coupling. Despite this result, ocean model coupling can reduce dynamical field error at a single level by up to 20%, and this was slightly greater (1-2%) with 3D ocean model coupling as compared to 1D ocean model coupling. Thus, while 3D ocean model coupling tended to generally produce more realistic simulations, its impact would likely be more profound for longer-term simulations.© Copyright 2015 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or [email protected] reviewe
A Cross-Layer Multicast-Push Unicast-Pull (MPUP) Architecture for Reliable File-Stream Distribution
No full textThe growing deployment of OpenFlow/SDN networks makes it increasingly possible to leverage network multi-cast services. This work proposes a novel cross-layer Multicast- Push Unicast Pull (MPUP) architecture that includes functionality in the application, transport and link layers to offer users a reliable file-stream distribution service to multiple subscribers. A prototype implementation of the MPUP architecture was realized in a new version of Local Data Manager (LDM), LDM7, a software program that has been in use since 1994 for real-time meteorology data distribution. LDM6, the currently deployed version, uses application-layer multicast. Experiment were run on the GENI infrastructure to compare LDM7 and LDM6. The two main findings are (i) LDM7 can be run at a higher sending rate than LDM6 allowing for improved performance (lower file-delivery latency), and (ii) to achieve the same performance, LDM7 uses significantly lower bandwidth and compute capacity. A three-fold improvement in performance improvement was possible with LDM7, and a bandwidth reduction from 350 Mbps to 21.4 Mbps was observed with 24 receivers.Peer reviewe
Controlled adsorption orientation for double-decker complexes
No full textControl of the molecular orientation of double-decker complexes comprised of rare-earth metals sandwiched with naphthalocyanine and porphyrin/phthalocyanine, at the interface of a graphite surface and I-phenyloctane solution, has been demonstrated for the future application of molecular rotor assembly. Scanning tunneling microscope images clarified the internal structures of the top ligands. The observed images indicate that naphthalocyanine ligands were selectively adsorbed onto the graphite surface and the counterpart ligands of porphyrin/phthalocyanine were oriented off the surface. Control of the orientation of monolayers of mixed double-decker complexes has also been demonstrated
Einsatzmöglichkeiten der Diskriminanzanalyse in der Marktforschung
No full textDecker R, Temme T. Einsatzmöglichkeiten der Diskriminanzanalyse in der Marktforschung. Discussion Paper No. 403. Faculty of Economics and Business Administration, Bielefeld University; 1998
Validação de modelos de simulação em sistemas elétricos utilizando medição fasorial sincronizada
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2015.A qualidade dos modelos tem sido uma constante preocupação dos engenheiros de planejamento, desde que a tarefa atribuída é o de predizer o desempenho do sistema de potência por meio de simulações digitais. Baseados nestes estudos são estabelecidos limites de transferências e políticas operativas que buscam preservar a segurança do sistema. O nível de confiança das simulações, como resposta esperada às perturbações, é principalmente influenciado pela qualidade dos modelos das unidades geradoras. Neste trabalho, é proposta uma nova metodologia para a validação de modelos de unidades geradoras utilizando registros obtidos de unidades de medição sincrofasorial. Das três fases propostas para o procedimento de validação, contribuições importantes são feitas na verificação e calibração. Na verificação é proposta uma nova função de discrepância global GDI (Global Discrepancy Indicator) para quantificar objetivamente a qualidade do modelo. A identificação dos parâmetros causadores das discrepâncias, factíveis de serem ajustados, é fundamental para o sucesso da calibração, devido à grande quantidade de parâmetros e as poucas variáveis registradas. Neste trabalho é mostrada a necessidade de se estabelecer, primeiro, quais parâmetros são observáveis; segundo, quais são os problemáticos e, terceiro, quais são determináveis de maneira única. Para cada um destes passos são propostas estratégias novas, baseadas nas propriedades da função GDI e nas sensibilidades das trajetórias do sistema. Para melhorar a observabilidade e validar cada um dos modelos componentes da unidade geradora é proposto o projeto de um tipo especial de unidade de medição sincrofasorial, com capacidade de registrar medidas fasoriais e medidas não fasoriais sincronizadas. Assim, é desenvolvida uma extensão da metodologia proposta envolvendo a ampliação do escopo de aplicação da simulação dinâmica híbrida, bem como da função GDI e de suas propriedades. A metodologia é validada realizando-se experimentos computacionais com registros virtuais e registros reais de uma unidade geradora de 270 MVA. Os resultados obtidos evidenciam as vantagens das propostas feitas e são considerados satisfatórios, aplicáveis e reproduzíveis para qualquer outro subsistema.Abstract : The quality of models has been a constant concern of planning engineers, since their main goal is to predict the performance of electrical power system through digital simulations. Based on these studies both transfer limits and operational policies are established in order to preserve system security. The confidence level of the simulations, measured as the system's fit to expected disturbances, is mainly influenced by the quality of the models that represent the generating units. This initiative proposes a new methodology to validate the model of generating units by using digital records sampled in synchrophasor measurement units. From the three stages proposed for the validation procedure, important contributions are made in the verification and calibration phases. In the verification, a new discrepancy function GDI (Global Discrepancy Indicator) is proposed to quantify in an objective way the quality of the model. The identification of the causative parameters of feasible discrepancies to be adjusted, define the final success of calibration, due to the large set of parameters and the few recorded variables. This work shows the need to establish, first, what parameters are observable; second, which ones are problematic, and third, which ones are determinable in a unique way. For each of these steps new strategies are proposed, based on GDI characteristics and trajectory sensitivities. To improve the observability and validate each model of the generator unit is proposed the design a special type of synchrophasor measurement unit with the ability to record synchronized phasor measurements and not phasor measurements. Additionally, it is proposed to extend the methodology in conjunction with the extended dynamic hybrid simulation and extended GDI functions. The methodology is verified by performing computational experiments with virtual records and real records of a 270 MVA generating unit. The results show the advantages of the proposals made and are considered satisfactory, applicable and reproducible for any other subsystem. Furthermore, when the special synchrophasor measurement unit proposed is used, the calibration phase performance is higher, due to the increase of observabilit
Lipid oxidation in emulsified food products
No full textMost lipids in food exist as colloidal dispersions stabilized by surface active agents that slow down the gravitational separation of oil and water. The surface active agents in emulsion create an oil-water interface that has major impacts on the distribution of the components in foods that impact lipid oxidation. This includes location and reactivity of prooxidative factors such as transition metals, lipid hydroperoxides and minor lipid components and antioxidants such as free radical scavengers and metal chelators. Understanding of how the physical properties of the lipid-oil interface in food emulsions impacts the chemistry of lipid oxidation has lead to new strategies to inhibit oxidation such as creating charged surfaces that electrostatically repel metals and thick interfaces that inhibit lipid-prooxidant interactions. As food formulations continue to move towards inclusion of more polyunsaturated fatty acids and the use of traditional antioxidants becomes more limited due to increased consumer demand for all natural foods, it is important to have a better understanding of the mechanisms of lipid oxidation in foods dispersion so that novel antioxidant technologies can be developped
Fine-tuning the Jurisprudence: The ECJ's Judicial Activism and Self-restraint
No full textLegal and political science scholars omit an important variable in explaining compliance with ECJ rulings: the fine-tuning in the follow-up cases. This paper shows with the Kohll/Decker social policy jurisprudence that, first, the Court applied the principles of free movement of services and goods to the Luxembourg health care system in the initial rulings in this series of cases and thereby challenged the institutional configuration of national welfare states. Step by step the ECJ extended the legal principles to other Member States and to similar cases. At the same time, however, the Court exercised self-restraint by narrowing the principles and by thus limiting the impact of its decisions largely to the less costly ambulatory sector. This fine-tuning of the jurisprudence influenced implementation processes and ultimately facilitated Member State compliance.European Court of Justice; European Court of Justice; judicial review; social policy; Luxembourg; free movement; health policy; welfare state; political science
A Measured Evolution of Database Integrity
No full text[EN] Inconsistency in large database systems is commonplace and therefore must be controlled in order to not get out of hand. Consistency in database systems is encoded by integrity constraints. Inconsistency thus corresponds to constraint violations. Database system services need to function in spite of extant integrity violations, but inconsistency should not increase beyond control in the course of the evolution of such systems. Evolution is effected by updates that may involve insertions and deletions of relational facts as well as schema updates. We show how to determine the causes of violations. Knowledge about such causes can be used to control inconsistency: an increase of integrity violations by updates can be prevented, while tolerating extant inconsistencies, even if the database schema is altered, and even if the schema is unsatisfiable.Supported by ERDF/FEDER and the Spanish MEC grant TIN2012-37719-C03-01.Decker, H. (2013). A Measured Evolution of Database Integrity. Lecture Notes in Computer Science. 8216:78-91. https://doi.org/10.1007/978-3-642-41366-7_7S78918216Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison-Wesley (1995)Arenas, M., Bertossi, L.E., Chomicki, J.: Consistent query answers in inconsistent databases. In: Proceedings of PODS, pp. 68–79. ACM Press (1999)Bertossi, L., Hunter, A., Schaub, T. (eds.): Inconsistency Tolerance. LNCS, vol. 3300. Springer, Heidelberg (2005)Clark, K.: Negation as failure. In: Gallaire, H., Minker, J. (eds.) Logic and Data Bases, pp. 293–322. Plenum Press (1978)Curino, C., Moon, H., Deutsch, A., Zaniolo, C.: Update rewriting and integrity constraint maintenance in a schema evolution support system: Prism++. PVLDB 4, 117–128 (2010)Decker, H.: Towards a dynamic inconsistency-tolerant schema maintenance. In: Song, I.-Y., et al. (eds.) ER Workshops 2008. LNCS, vol. 5232, pp. 89–98. Springer, Heidelberg (2008)Decker, H.: Basic causes for the inconsistency tolerance of query answering and integrity checking. In: Proc. 21st DEXA Workshops, pp. 318–322. IEEE CSP (2010)Decker, H.: Toward a uniform cause-based approach to inconsistency-tolerant database semantics. In: Meersman, R., Dillon, T., Herrero, P. (eds.) OTM 2010. LNCS, vol. 6427, pp. 983–998. Springer, Heidelberg (2010)Decker, H.: Answers that have integrity. In: Schewe, K.-D. (ed.) SDKB 2010. LNCS, vol. 6834, pp. 54–72. Springer, Heidelberg (2011)Decker, H.: Causes for inconsistency-tolerant schema update management. In: Proc. 27th ICDE Workshops, pp. 157–161. IEEE CSP (2011)Decker, H.: Consistent explanations of answers to queries in inconsistent knowledge bases. In: Roth-Berghofer, T., Tintarev, N., Leake, D. (eds.) Proc. IJCAI 2011 Workshop ExaCt, pp. 71–80 (2011)Decker, H.: Partial repairs that tolerate inconsistency. In: Eder, J., Bielikova, M., Tjoa, A.M. (eds.) ADBIS 2011. LNCS, vol. 6909, pp. 389–400. Springer, Heidelberg (2011)Decker, H.: Measure-based inconsistency-tolerant maintenance of database integrity. In: Schewe, K.-D., Thalheim, B. (eds.) SDKB 2013. LNCS, vol. 7693, pp. 149–173. Springer, Heidelberg (2013)Decker, H., de Marín, R.J.: Enabling business rules for concurrent transactions. In: Proc. Int. Conf. on P2P, Parallel, Grid, Cloud and Internet Computing, pp. 207–212. IEEE CPS (2001)Decker, H., Martinenghi, D.: Classifying integrity checking methods with regard to inconsistency tolerance. In: Proceedings of the 10th International ACM SIGPLAN Conference on Principles and Practice of Declarative Programming, pp. 195–204. ACM Press (2008)Decker, H., Martinenghi, D.: Inconsistency-tolerant integrity checking. IEEE Transactions of Knowledge and Data Engineering 23(2), 218–234 (2011)Gupta, A., Sagiv, Y., Ullman, J.D., Widom, J.: Constraint checking with partial information. In: Proceedings of PODS 1994, pp. 45–55. ACM Press (1994)Meliou, A., Gatterbauer, W., Moore, K., Suciu, D.: The complexity of causality and responsibility for query answers and non-answers. In: Proc. 37th VLDB, pp. 34–45 (2011)Türker, C.: Schema evolution in SQL-99 and commercial (object-)relational DBMS. In: Balsters, H., De Brock, B., Conrad, S. (eds.) FoMLaDO 2000 and DEMM 2000. LNCS, vol. 2065, pp. 1–32. Springer, Heidelberg (2001
- …
