Can wavelets improve the representation of forecast error covariances in variational data assimilation?

Two wavelet-based control variable transform schemes are described and are used to model some important features of forecast error statistics for use in variational data assimilation. The first is a conventional wavelet scheme and the other is an approximation of it. Their ability to capture the position and scale-dependent aspects of covariance structures is tested in a two-dimensional latitude-height context. This is done by comparing the covariance structures implied by the wavelet schemes with those found from the explicit forecast error covariance matrix, and with a non-wavelet- based covariance scheme used currently in an operational assimilation scheme. Qualitatively, the wavelet-based schemes show potential at modeling forecast error statistics well without giving preference to either position or scale-dependent aspects. The degree of spectral representation can be controlled by changing the number of spectral bands in the schemes, and the least number of bands that achieves adequate results is found for the model domain used. Evidence is found of a trade-off between the localization of features in positional and spectral spaces when the number of bands is changed. By examining implied covariance diagnostics, the wavelet-based schemes are found, on the whole, to give results that are closer to diagnostics found from the explicit matrix than from the nonwavelet scheme. Even though the nature of the covariances has the right qualities in spectral space, variances are found to be too low at some wavenumbers and vertical correlation length scales are found to be too long at most scales. The wavelet schemes are found to be good at resolving variations in position and scale-dependent horizontal length scales, although the length scales reproduced are usually too short. The second of the wavelet-based schemes is often found to be better than the first in some important respects, but, unlike the first, it has no exact inverse transform.

An evaluation of the use of Cottonseed cake in the diet of growing pigs

An experiment was conducted to determine the effects of including cottonseed cake in rations for weaned growing pigs. Thirty-two Landrace x Large White pigs, weighing 20-24 kg, were included in four blocks formed on the basis of initial weight within sex in an otherwise completely randomized block design. The pigs were killed when they reached a live weight of 75.0 +/- 2.0 kg and the half careases were analysed into cuts and the weights of the organs were recorded. An estimate of the productivity of the pigs on each diet was calculated. Cottonseed cake reduced the voluntary feed intake (p < 0.001) and live weight gains (p < 0.001) and increased the heart, kidney and liver weights (p < 0.01). The pigs on the soya bean-based control diet took the shortest time to reach slaughter weight. The result was probably in part due to lysine deficiency and in part to the effect of free gossypol. It was found that it is at present cost-effective to include cottonseed cake in pig weaner grower diets up to 300 g/kg in Cameroon.

Muscle hypertrophy driven by myostatin blockade does not require stem/precursor-cell activity

Myostatin, a member of the TGF-beta family, has been identified as a powerful inhibitor of muscle growth. Absence or blockade of myostatin induces massive skeletal muscle hypertrophy that is widely attributed to proliferation of the population of muscle fiber-associated satellite cells that have been identified as the principle source of new muscle tissue during growth and regeneration. Postnatal blockade of myostatin has been proposed as a basis for therapeutic strategies to combat muscle loss in genetic and acquired myopathies. But this approach, according to the accepted mechanism, would raise the threat of premature exhaustion of the pool of satellite cells and eventual failure of muscle regeneration. Here, we show that hypertrophy in the absence of myostatin involves little or no input from satellite cells. Hypertrophic fibers contain no more myonuclei or satellite cells and myostatin had no significant effect on satellite cell proliferation in vitro, while expression of myostatin receptors dropped to the limits of detectability in postnatal satellite cells. Moreover, hypertrophy of dystrophic muscle arising from myostatin blockade was achieved without any apparent enhancement of contribution of myonuclei from satellite cells. These findings contradict the accepted model of myostatin-based control of size of postnatal muscle and reorient fundamental investigations away from the mechanisms that control satellite cell proliferation and toward those that increase myonuclear domain, by modulating synthesis and turnover of structural muscle fiber proteins. It predicts too that any benefits of myostatin blockade in chronic myopathies are unlikely to impose any extra stress on the satellite cells.

The relative order and inverses of recurrent networks

Differential geometry is used to investigate the structure of neural-network-based control systems. The key aspect is relative order—an invariant property of dynamic systems. Finite relative order allows the specification of a minimal architecture for a recurrent network. Any system with finite relative order has a left inverse. It is shown that a recurrent network with finite relative order has a local inverse that is also a recurrent network with the same weights. The results have implications for the use of recurrent networks in the inverse-model-based control of nonlinear systems.

Causal evidence for frontal involvement in memory target maintenance by posterior brain areas during distracter interference of visual working memory

Dorsolateral prefrontal cortex (DLPFC) is recruited during visual working memory (WM) when relevant information must be maintained in the presence of distracting information. The mechanism by which DLPFC might ensure successful maintenance of the contents of WM is, however, unclear; it might enhance neural maintenance of memory targets or suppress processing of distracters. To adjudicate between these possibilities, we applied time-locked transcranial magnetic stimulation (TMS) during functional MRI, an approach that permits causal assessment of a stimulated brain region's influence on connected brain regions, and evaluated how this influence may change under different task conditions. Participants performed a visual WM task requiring retention of visual stimuli (faces or houses) across a delay during which visual distracters could be present or absent. When distracters were present, they were always from the opposite stimulus category, so that targets and distracters were represented in distinct posterior cortical areas. We then measured whether DLPFC-TMS, administered in the delay at the time point when distracters could appear, would modulate posterior regions representing memory targets or distracters. We found that DLPFC-TMS influenced posterior areas only when distracters were present and, critically, that this influence consisted of increased activity in regions representing the current memory targets. DLPFC-TMS did not affect regions representing current distracters. These results provide a new line of causal evidence for a top-down DLPFC-based control mechanism that promotes successful maintenance of relevant information in WM in the presence of distraction.

Estudo de estratégias de otimização para poços de petróleo com elevação por bombeio de cavidades progressivas

The progressing cavity pump artificial lift system, PCP, is a main lift system used in oil production industry. As this artificial lift application grows the knowledge of it s dynamics behavior, the application of automatic control and the developing of equipment selection design specialist systems are more useful. This work presents tools for dynamic analysis, control technics and a specialist system for selecting lift equipments for this artificial lift technology. The PCP artificial lift system consists of a progressing cavity pump installed downhole in the production tubing edge. The pump consists of two parts, a stator and a rotor, and is set in motion by the rotation of the rotor transmitted through a rod string installed in the tubing. The surface equipment generates and transmits the rotation to the rod string. First, is presented the developing of a complete mathematical dynamic model of PCP system. This model is simplified for use in several conditions, including steady state for sizing PCP equipments, like pump, rod string and drive head. This model is used to implement a computer simulator able to help in system analysis and to operates as a well with a controller and allows testing and developing of control algorithms. The next developing applies control technics to PCP system to optimize pumping velocity to achieve productivity and durability of downhole components. The mathematical model is linearized to apply conventional control technics including observability and controllability of the system and develop design rules for PI controller. Stability conditions are stated for operation point of the system. A fuzzy rule-based control system are developed from a PI controller using a inference machine based on Mandami operators. The fuzzy logic is applied to develop a specialist system that selects PCP equipments too. The developed technics to simulate and the linearized model was used in an actual well where a control system is installed. This control system consists of a pump intake pressure sensor, an industrial controller and a variable speed drive. The PI control was applied and fuzzy controller was applied to optimize simulated and actual well operation and the results was compared. The simulated and actual open loop response was compared to validate simulation. A case study was accomplished to validate equipment selection specialist system

Uma abordagem comportamental para inserção de robôs em ambientes culturais

In this work, we propose methodologies and computer tools to insert robots in cultural environments. The basic idea is to have a robot in a real context (a cultural space) that can represent an user connected to the system through Internet (visitor avatar in the real space) and that the robot also have its representation in a Mixed Reality space (robot avatar in the virtual space). In this way, robot and avatar are not simply real and virtual objects. They play a more important role in the scenery, interfering in the process and taking decisions. In order to have this service running, we developed a module composed by a robot, communication tools and ways to provide integration of these with the virtual environment. As welI we implemented a set of behaviors with the purpose of controlling the robot in the real space. We studied available software and hardware tools for the robotics platform used in the experiments, as welI we developed test routines to determine their potentialities. Finally, we studied the behavior-based control model, we planned and implemented alI the necessary behaviors for the robot integration to the real and virtual cultural spaces. Several experiments were conducted, in order to validate the developed methodologies and tools

Influência de fatores antinutricionais da leucena (Leucaena leucocephala e Leucaena cunningan) e do feijão guandu (Cajanus cajan) sobre o epitélio intestinal e o desempenho de frangos de corte

Um experimento foi conduzido para avaliar a influência de fatores antinutricionais de alguns alimentos sobre o epitélio intestinal e o desempenho de frangos de corte. Foram utilizados 480 pintos de um dia de idade, em um delineamento inteiramente casualizado com quatro tratamentos (A = ração testemunha à base de milho e soja; B = ração contendo Leucaena leucocephala - 6% [LL]; C = ração contendo Leucaena cunningan - 6% [LC] e D = ração contendo feijão guandu - Cajanus cajan - 20% [CC]), quatro repetições e 30 aves por unidade experimental. Houve redução de ganho de peso e aumento da conversão alimentar com a utilização de LL e LC, no período de 1a 21 e de 1a 42 dias de idade. Aos 21 dias de idade, observou-se aumento no tamanho dos vilos do jejuno e na relação vilo:cripta do jejuno e íleo, nas aves que receberam LC. Houve aumento significativo (P<0,05) das células caliciformes no duodeno e jejuno em aves de todos os tratamentos e apenas LL e LC aumentaram as células caliciformes do íleo. Aos 42 dias de idade, houve aumento no número de células caliciformes causado por CC no duodeno e por LL, LC e CC no íleo. O consumo de ração e a profundidade de cripta não foram influenciados. A alteração da morfologia da vilosidade do jejuno, bem como a alteração na relação vilo:cripta no período inicial, influenciou negativamente o ganho de peso e a conversão alimentar nos períodos inicial e total.

Estabilidade, desempenho e observação de estado de sistemas chaveados afins: aplicações aos conversores CC-CC

Pós-graduação em Engenharia Elétrica - FEIS

Desempenho da tilápia-do-Nilo arraçoada com dietas contendo farinha de sangue bovino atomizado ou convencional

The study evaluated the performance and carcass composition index of Nile tilapia (Oreochromis niloticus) fed with diets containing increasing levels of spray-dried blood meal (SDBM) and vat-dried blood meal (VDBM) and formulated based on digestible amino acids. Two hundred and fifty-two fingerlings were distributed in a completely randomized design, in a (2 x 4) + 1 factorial model, two types of blood meal with four levels of each blood meal in the diet, and a control diet (without blood meal), with four replications. The treatments consisted of soybean meal-based control diet, with 34% digestible protein (DP) and 3,200 kcal of digestible energy kg-1 (DE), plus four diets formulated with SDBM and four diets with VDBM, containing 5, 10, 15 and 20% of each meal in feed, maintaining identical DP, DE, phosphorus, calcium, lysine, methionine, threonine and tryptophan levels as those of the control diet. The results show that it is possible to use up to 15% VDBM in diets of Nile tilapia (O. niloticus) between 5 to 150 g of body weight.

Despacho ótimo de potências ativa e reativa de sistema elétricos multi-áreas considerando restrições físicas, econômicas e ambientais =: Envronmentally constrained active-reactive optimal power flow-a compromising strategy for economic-emission dispatch and a multi-area paradigm

Pós-graduação em Engenharia Elétrica - FEIS

Dynamic Routing in Translucent WDM Optical Networks

Translucent WDM optical networks use sparse placement of regenerators to overcome the impairments and wavelength contention introduced by fully transparent networks, and achieve a performance close to fully opaque networks with much less cost. Our previous study proved the feasibility of translucent networks using sparse regeneration technique. We addressed the placement of regenerators based on static schemes allowing only fixed number of regenerators at fixed locations. This paper furthers the study by proposing a suite of dynamical routing schemes. Dynamic allocation, advertisement and discovery of regeneration resources are proposed to support sharing transmitters and receivers between regeneration and access functions. This study follows the current trend in optical networking industry by utilizing extension of IP control protocols. Dynamic routing algorithms, aware of current regeneration resources and link states, are designed to smartly route the connection requests under quality constraints. A hierarchical network model, supported by the MPLS-based control plane, is also proposed to provide scalability. Experiments show that network performance is improved without placement of extra regenerators.

La qualità erogata da un'azienda di trasporto collettivo in ambito urbano: calcolo del livello di servizio delle principali linee di ATC (BO)

Oggetto di questa tesi è lo studio della qualità del servizio di trasporto erogato che condiziona la qualità percepita dall’utente, poiché spesso proprio a causa di un errato processo di pianificazione e gestione della rete, molte aziende non sono in grado di consolidare un alto livello di efficienza che permetta loro di attrarre e servire la crescente domanda. Per questo motivo, si è deciso di indagare sugli aspetti che determinano la qualità erogata e sui fattori che la influenzano, anche attraverso la definizione di alcuni indicatori rappresentativi del servizio erogato. L’area di studio considerata è stata quella urbana di Bologna, e sono state prese in esame due linee di ATC, la 19 e la 27, caratterizzate entrambe da una domanda di trasporto molto elevata. L’interesse è ricaduto in modo particolare sugli aspetti legati alla regolarità del servizio, ovvero al rispetto della cadenza programmata delle corse e alla puntualità, ossia il rispetto dell’orario programmato delle stesse. Proprio da questi due aspetti, infatti, dipende in larga misura la percezione della qualità che gli utenti hanno del servizio di trasporto collettivo. Lo studio è stato condotto sulla base di dati raccolti attraverso due campagne di rilevamento, una effettuata nel mese di maggio dell’anno 2008 e l’altra nel mese di settembre dello stesso anno. La scelta del periodo, della zona e delle modalità di rilevamento è strettamente connessa all’obiettivo prefissato. Il servizio è influenzato dalle caratteristiche del sistema di trasporto: sia da quelle legate alla domanda che da quelle legate all’offerta. Nel caso della domanda di trasporto si considera l’influenza sul servizio del numero di passeggeri saliti e del tempo di sosta alle fermate. Nel caso dell’offerta di trasporto si osservano soprattutto gli aspetti legati alla rete di trasporto su cui si muovono gli autobus, analizzando quindi i tempi di movimento e le velocità dei mezzi, per vedere come le caratteristiche dell’infrastruttura possano condizionare il servizio. A tale proposito è opportuno dire che, mentre i dati della prima analisi ci sono utili per lo studio dell’influenza del tempo di sosta sull’intertempo, nella seconda analisi si vuole cercare di effettuare ulteriori osservazioni sull’influenza del tempo di movimento sulla cadenza, prendendo in esame altri elementi, come ad esempio tratti di linea differenti rispetto al caso precedente. Un’attenzione particolare, inoltre, verrà riservata alla verifica del rispetto della cadenza, dalla quale scaturisce la definizione del livello di servizio per ciò che riguarda la regolarità. Per quest’ultima verrà, inoltre, determinato anche il LOS relativo alla puntualità. Collegato al problema del rispetto della cadenza è il fenomeno dell’accodamento: questo si verifica quando i mezzi di una stessa linea arrivano contemporaneamente ad una fermata uno dietro l’altro. L’accodamento ha, infatti, origine dal mancato rispetto della cadenza programmata tra i mezzi ed è un’evidente manifestazione del mal funzionamento di un servizio di trasporto. Verrà infine condotta un’analisi dei fattori che possono influenzare le prestazioni del servizio di trasporto pubblico, così da collocare i dati ottenuti dalle operazioni di rilevamento in un quadro più preciso, capace di sottolineare alcuni elementi di criticità e possibili rapporti di causalità.

Mobi - kids - rischio di tumori cerebrali ed esposizione a campi a radiofrequenza nei bambini e negli adolescenti

Introduzione. Il rapido e globale incremento dell’utilizzo dei telefoni cellulari da parte degli adolescenti e dei bambini ha generato un considerevole interesse circa i possibili effetti sulla salute dell’esposizione a campi elettromagnetici a radiofrequenza. Perciò è stato avviato lo studio internazionale caso-controllo Mobi-kids, all’interno del quale si colloca quello italiano condotto in 4 Regioni (Piemonte, Lombardia, Toscana, Emilia-Romagna). Obiettivi. Lo studio ha come obiettivo quello di valutare la stima del rischio degli effetti potenzialmente avversi di queste esposizioni sul sistema nervoso centrale nei bambini e negli adolescenti. Materiali e Metodi. La popolazione include tutte le persone di età compresa tra 10 e 24 anni residenti nelle 4 Regioni, con una diagnosi confermata di neoplasia cerebrale primitiva, diagnosticata durante il periodo di studio (3 anni). Sono stati selezionati due controlli - ospedalizzati per appendicite acuta - per ciascun caso. I controlli sono stati appaiati individualmente a ciascun caso per età, sesso e residenza del caso. Risultati. In Italia sono stati intervistati a Giugno 2014, 106 casi e 191 controlli. In Emilia-Romagna i casi reclutati sono stati fino ad ora 21 e i controlli 20, con una rispondenza del’81% e dell’65% rispettivamente. Dei 41 soggetti totali, il 61% era di sesso maschile con un’età media generale pari a 16,5 (±4,5) anni. Inoltre il 44% degli intervistati proveniva dalla classe di età più giovane (10-14). In merito allo stato di appaiamento, nella nostra Regione sono state effettuate 7 triplette (33%) - 1 caso e 2 controlli - e 6 doppiette (29%) - 1 caso ed 1 controllo. Conclusioni. Nonostante le varie difficoltà affrontate data la natura del progetto, l’esperienza maturata fin ad ora ha comunque portato alla fattibilità dello studio e porterà probabilmente a risultati che contribuiranno alla comprensione dei potenziali rischi di neoplasie cerebrali associati all'uso di telefoni cellulari tra i giovani.

ATP modeling of internal transformer faults for relay performance testing

Transformers are very important elements of any power system. Unfortunately, they are subjected to through-faults and abnormal operating conditions which can affect not only the transformer itself but also other equipment connected to the transformer. Thus, it is essential to provide sufficient protection for transformers as well as the best possible selectivity and sensitivity of the protection. Nowadays microprocessor-based relays are widely used to protect power equipment. Current differential and voltage protection strategies are used in transformer protection applications and provide fast and sensitive multi-level protection and monitoring. The elements responsible for detecting turn-to-turn and turn-to-ground faults are the negative-sequence percentage differential element and restricted earth-fault (REF) element, respectively. During severe internal faults current transformers can saturate and slow down the speed of relay operation which affects the degree of equipment damage. The scope of this work is to develop a modeling methodology to perform simulations and laboratory tests for internal faults such as turn-to-turn and turn-to-ground for two step-down power transformers with capacity ratings of 11.2 MVA and 290 MVA. The simulated current waveforms are injected to a microprocessor relay to check its sensitivity for these internal faults. Saturation of current transformers is also studied in this work. All simulations are performed with the Alternative Transients Program (ATP) utilizing the internal fault model for three-phase two-winding transformers. The tested microprocessor relay is the SEL-487E current differential and voltage protection relay. The results showed that the ATP internal fault model can be used for testing microprocessor relays for any percentage of turns involved in an internal fault. An interesting observation from the experiments was that the SEL-487E relay is more sensitive to turn-to-turn faults than advertized for the transformers studied. The sensitivity of the restricted earth-fault element was confirmed. CT saturation cases showed that low accuracy CTs can be saturated with a high percentage of turn-to-turn faults, where the CT burden will affect the extent of saturation. Recommendations for future work include more accurate simulation of internal faults, transformer energization inrush, and other scenarios involving core saturation, using the newest version of the internal fault model. The SEL-487E relay or other microprocessor relays should again be tested for performance. Also, application of a grounding bank to the delta-connected side of a transformer will increase the zone of protection and relay performance can be tested for internal ground faults on both sides of a transformer.