931 resultados para Control system design


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BACKGROUND: Primary care physicians are well positioned to provide counselling for overweight and obese patients, but no prospective study has assessed the effectiveness of this counselling in primary care. We aimed to evaluate weight reduction counselling by primary care physicians, and its relationship with weight change and patients' behaviour to control weight. DESIGN: A prospective cohort study. METHODS: We enrolled 523 consecutive overweight and obese patients from two Swiss academic primary care clinics. Physicians and patients were blinded to the study aims. We assessed the use of 10 predefined counselling strategies for weight reduction, and weight change and behaviour to control weight after 1 year. RESULTS: Sixty-five per cent of patients received some form of weight reduction counselling whereas 35% received no counselling. A total of 407 patients completed the 1-year follow-up. Those who received counselling lost on average (SD) 1.0 (5.0) kg after 1 year, whereas those who were not advised gained 0.3 (5.0) kg (P = 0.02). In multivariate analysis, each additional counselling strategy was associated with a mean weight loss of 0.2 kg (95% confidence interval 0.03-0.4, P = 0.02). Patients counselled by their physician had more favourable behaviour to control weight than those not counselled, such as setting a target weight (56 versus 36%) or visiting a dietician (23 versus 10%, both P < 0.001). CONCLUSIONS: Weight reduction counselling by primary care physicians is associated with a modest weight loss and favourable behaviour to control weight. However, many obese and overweight patients receive no advice on weight loss during primary care visits.

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Purpose: To determine dose thresholds, in term of CTDIvol, where subtle anatomical structures of pediatric CT images becomes no more detectable and compare them to the most recent Reference Dose Levels (DRL) proposed in the UK, Germany and Switzerland. Materials and methods: A GE LightSpeed-Ultra scanner (MSCT 8 slices) was used to perform chest and abdomen acquisitions on 8 patients (age range 2 to 16 years old) to provide a set of gold standard images. Dose reductions were then simulated by introducing image noise on raw data to provide simulated CT images with CTDIvol ranging from 2 to 22 mGy. All images were reviewed and scored independently by four experienced radiologists using the VGA methodology (Visual Grading Analysis) to determine the dose threshold where a significant loss of normal anatomy conspicuity appeared. Data were analyzed with ANOVA and Tukey HSD tests, a p >0.05 was considered to be significant. Results: No significant difference in VGA scoring appeared for CTDIvol leading to image noise levels lower than 10 and 25 HU for respectively abdominal and chest acquisitions. These data can thus be used to set the AEC (automatic exposure control) system of units having similar noise properties than the GE LightSpeed-Ultra used in this study. The present DRLs proposed for pediatric CT acquisitions are compatible with an excellent image quality level. Conclusion: The differences of DRL values proposed in Europe for pediatric acquisitions are marginal and assure a very good image quality level. The results of this study allow to further optimize the acquisition protocol by giving Noise Index value to set the AEC device.

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ABSTRACT Soil tillage that maintains the productivity of sugarcane plantations, providing an area for the root development and without traffic on crop rows, has given rise to new technologies in rural areas. The purpose of this study was to evaluate the soil physical properties in two sugarcane plantations, one of which was prepared with deep tilling and the other with conventional tillage. The experiment was conducted in Lençóis Paulista, São Paulo State. Soil penetration resistance and relative density were analyzed. The cone index was lower in deep-tilled soil without traffic in all layers, than in deep-tilled soil with traffic and in conventional tillage. In both tillage treatments, the relative density values were acceptable in the 0.00-0.15 m soil layer, but considered detrimental for sugarcane development in the 0.15-0.30 and 0.30-0.45 m layers.

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BACKGROUND: Black women are at greater risk of obesity than are white women, perhaps because of their lower levels of physical activity. OBJECTIVE: We compared free-living activity energy expenditure (AEE) in sedentary white and black women (in overweight and normal-weight states) and in never-overweight control subjects. DESIGN: Subjects included 46 women (23 white, 23 black) studied while overweight and after reaching a normal weight and 38 female control subjects (23 white, 15 black). Diet, without exercise training, resulted in a mean weight loss of 13 kg and a body mass index (in kg/m(2)) < 25. Body composition, sleeping energy expenditure, free-living total energy expenditure, and the energy cost of activity and aerobic capacity were assessed before and after weight loss under 4-wk, diet-controlled, weight-stable conditions and in the control subjects. AEE was defined as above-sleep energy expenditure. RESULTS: No significant racial differences in body composition, before or after weight loss, were found. After weight loss, AEE and aerobic capacity increased in the white women and decreased in the black women (P < 0.05 and P < 0.02, respectively). After weight loss, but not before, the white women had a significantly higher mean AEE than did the black women (2448 +/- 979 and 1728 +/- 1373 kJ/d, respectively; P < 0.05), approximating AEEs in the white (2314 +/- 1105) and black (2310 +/- 1251) control subjects. CONCLUSIONS: Relative to the responses of the white women to diet-induced weight loss, the black women became less fit and less physically active. Induction of a normal body weight in overweight black women appeared to produce a more obesity-prone state, favoring weight relapse.

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S’arriba a un acord entre el grup de recerca GREFEMA i ViCOROB per estudiar els propulsors de palesutilitzats fins a l’actualitat en el robot submarí Girona 500, de forma que el model creatserveixi d’eina per apoder estudiar qualsevol tipus de propulsor que es vulgui fer servir.Es crearà un model de simulació amb CFD d’ANSYS per tal de poder recrear qualsevol situació ambqualsevol model de propulsor que es vulgui emprar, estalviant en costos de compra o fabricació, a mésd’evitar un muntatge experimental que pot no ser del tot fiable.A partir de geometries de propulsors de pales comercials existents es realitzarà una simulació amb elprograma de dinàmica de fluids computacional (CFD) d’ANSYS.La informació proporcionada per l’eina de simulació es compararan amb els resultats obtinguts de formaempírica a les instal•lacions del Parc Científic i Tecnològic de la Universitat de Girona i amb el model teòric.D’aquesta forma, es comprovarà la bondat de la simulació i es validarà el model numèric utilitzat

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El grup VICOROB de la UdG té una àmplia experiència en l’àmbit dels vehicles irobots submarins, amb diferents prototips degudament validats experimentalment.L’interès d’aquest grup de recerca és anar més enllà i conèixer exactament elcomportament del vehicle dins de l’aigua.El grup VICOROB disposa d’un vehicle subaquàtic, l’anomenat GIRONA 500 que haestat dissenyat com una plataformad'investigació amb capacitat per tornara configurar-se per a moltes aplicacionsdiferents, que van des dels clàssicssonar i servei d’imatges de vídeo fins atasques d'intervenció autònomesdifícilsL’objectiu és d’aquest projecte és obtenir a partir de la geometria real del vehicleGIRONA 500 els coeficients hidrodinàmics del submarí complet i de solamentl’estructura per així conèixer l’efecte hidrodinàmic del nombre de propulsors acoblats alrespectiu vehicle aquàtic

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This report documents work undertaken in the demonstration of a low-cost Automatic Weight and Classification System (AWACS). An AWACS procurement specification and details of the results of the project are also included. The intent of the project is to support and encourage transferring research knowledge to state and local agencies and manufacturers through field demonstrations. Presently available, Weigh-in-Motion and Classification Systems are typically too expensive to permit the wide deployment necessary to obtain representative vehicle data. Piezo electric technology has been used in the United Kingdom and Europe and is believed to be the basic element in a low-cost AWACS. Low-cost systems have been installed at two sites, one in Portland Cement Concrete (PCC) pavement in Iowa and the other in Asphaltic Cement Concrete (ACC) pavement in Minnesota to provide experience with both types of pavement. The systems provide axle weights, gross vehicle weight, axle spacing, vehicle classification, vehicle speed, vehicle count, and time of arrival. In addition, system self-calibration and a method to predict contact tire pressure is included in the system design. The study has shown that in the PCC pavement, the AWACS is capable of meeting the needs of state and federal highway agencies, producing accuracies comparable to many current commercial WIM devices. This is being achieved at a procurement cost of substantially less than currently available equipment. In the ACC pavement the accuracies were less than those observed in the PCC pavement which is concluded to result from a low pavement rigidity at this site. Further work is needed to assess the AWACS performance at a range of sites in ACC pavements.

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This abstract presents how we redesigned, with user-centred design methods, the way we organize and present the content on the UOC Virtual Library website. The content is now offered in a way that is more intuitive, usable and easy to understand, based on criteria of customization, transparency and proximity.The techniques used to achieve these objectives included benchmarking, interviews and focus groups during the user requirement capture phase and user tests to assess the process and results.

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The GABAergic system modulates respiratory activity and undergoes substantial changes during early life. Because this maturation process is sensitive to stress, we tested the hypothesis that gestational stress (GS) alters development of GABAergic modulation of respiratory control in rat pups. The respiratory responses to the selective GABAA receptor agonist muscimol were compared between pups born to dams subjected to GS (bright light and predator odor; 20 min/day from G9 to G19) or maintained under standard (control) conditions. Respiratory activity was measured on 1 and 4 days old pups of both sexes using in vivo (whole body plethysmography) and in vitro (isolated brainstem-spinal cord preparation) approaches. In intact pups, muscimol injection (0.75 mg/kg; i.p.) depressed minute ventilation; this response was less in GS pups, and at P4, muscimol augmented minute ventilation in GS females. Bath application of muscimol (0.01-0.5 μM) onto brainstem preparations decreased inspiratory (C4) burst frequency and amplitude in a dose-dependent manner; the responsiveness decreased with age. However, GS had limited effects on these results. We conclude that the results obtained in vivo are consistent with our hypothesis and show that GS delays maturation of GABAergic modulation of respiratory activity. The differences in the results observed between experimental approaches (in vivo versus in vitro) indicate that the effect of prenatal stress on maturation of GABAergic modulation of respiratory control mainly affects the peripheral/metabolic components of the respiratory control system.

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This paper presents a simple and fast solution to the problem of finding the time variations of the forces that keep the object equilibrium when a finger is removed from a three contact point grasp or a finger is added to a two contact point grasp, assuming the existence of an external perturbation force (that can be the object weight itself). The procedure returns force set points for the control system of a manipulator device in a regrasping action. The approach was implemented and a numerical example is included in the paper to illustrate how it works.

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Line converters have become an attractive AC/DC power conversion solution in industrial applications. Line converters are based on controllable semiconductor switches, typically insulated gate bipolar transistors. Compared to the traditional diode bridge-based power converters line converters have many advantageous characteristics, including bidirectional power flow, controllable de-link voltage and power factor and sinusoidal line current. This thesis considers the control of the lineconverter and its application to power quality improving. The line converter control system studied is based on the virtual flux linkage orientation and the direct torque control (DTC) principle. A new DTC-based current control scheme is introduced and analyzed. The overmodulation characteristics of the DTC converter are considered and an analytical equation for the maximum modulation index is derived. The integration of the active filtering features to the line converter isconsidered. Three different active filtering methods are implemented. A frequency-domain method, which is based on selective harmonic sequence elimination, anda time-domain method, which is effective in a wider frequency band, are used inharmonic current compensation. Also, a voltage feedback active filtering method, which mitigates harmonic sequences of the grid voltage, is implemented. The frequency-domain and the voltage feedback active filtering control systems are analyzed and controllers are designed. The designs are verified with practical measurements. The performance and the characteristics of the implemented active filtering methods are compared and the effect of the L- and the LCL-type line filteris discussed. The importance of the correct grid impedance estimate in the voltage feedback active filter control system is discussed and a new measurement-based method to obtain it is proposed. Also, a power conditioning system (PCS) application of the line converter is considered. A new method for correcting the voltage unbalance of the PCS-fed island network is proposed and experimentally validated.

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Vanerin tai kertopuun valmistusprosessissaviilun kuivaukseen käytetään suurin osa koko valmistusprosessin primäärienergiasta. Viilunkuivauskoneessa viilun sisältämä vesi siirretään tyypillisesti prosessihöyryllä lämmitettyyn viilunkuivaajan kiertoilmaan höyrystämällä ja poistetaanviilunkuivaajasta poistoilman mukana. Viilunkuivaajan poistoilma on lämmintä jaerittäin suuren kosteuspitoisuutensa takia sisältää runsaasti energiaa. Tyypillisellä viilunkuivaajalla poistoilmaan sitoutunut lämpöteho vaihtelee prosessiolosuhteista riippuen välillä 2,7-5,7 MW. Diplomityössä tutkittiin viilunkuivaajan poistoilman sisältämän lämmön talteenottoa laitteistolla, johon kuuluu lämmöntalteenottopesuri, jossa poistoilmalla lämmitetään tuotantolaitoksen tukkipuun hautomon kiertovettä sekä ilma-ilma-lämmönsiirrin, jolla lämmitetään pesurista poistuvan ilman jäännöslämmöllä ulkoilmaa tehdassalin tuloilmakäyttöön. Työn tavoitteena oli kehittää lämmöntalteenottojärjestelmän suunnittelua, mitoitusta ja ajotapoja. Työssä analysoitiin teoreettisesti pesuria ja ilmalämmönsiirrintä, kehitettiin lämmöntalteenottopesurin simulointimenetelmä ja mitattiin toiminnassa olevia talteenottolaitteistoja. Tutkimuksessa todettiin lämmöntalteenottohyötysuhteen vaihtelevan lämmityskaudella välillä 50-70 %. Lämmöntalteenottolaitteiston pesurin veteen saatava teho riippuu ensisijaisesti viilunkuivaajan poistoilman lämpösisällöstä, joka on enimmäkseen kosteusriippuvainen ja ilmanvaihtoilmaan saatava teho ulkolämpö-tilan määräämästä tehontarpeesta. Pesurin vesijärjestelmän vaikutusmekanismit pesurin suorituskykyyn tunnistettiin ja niiden pohjalta annetaan suositukset mitoitukseen ja ajotapaan. Lämmöntalteenottolaitteiston lämpötehon tasapainottamiseen pesurin ja ilma-ilma-lämmönsiirtimen välillä mitoituksen avulla esitellään työkalut.

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Cooperative transmission can be seen as a "virtual" MIMO system, where themultiple transmit antennas are in fact implemented distributed by the antennas both at the source and the relay terminal. Depending on the system design, diversity/multiplexing gainsare achievable. This design involves the definition of the type of retransmission (incrementalredundancy, repetition coding), the design of the distributed space-time codes, the errorcorrecting scheme, the operation of the relay (decode&forward or amplify&forward) and thenumber of antennas at each terminal. Proposed schemes are evaluated in different conditionsin combination with forward error correcting codes (FEC), both for linear and near-optimum(sphere decoder) receivers, for its possible implementation in downlink high speed packetservices of cellular networks. Results show the benefits of coded cooperation over directtransmission in terms of increased throughput. It is shown that multiplexing gains areobserved even if the mobile station features a single antenna, provided that cell wide reuse of the relay radio resource is possible.

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Työn kirjallisuusosassa perehdytään paperikoneen online-mittarien toimintaan, poikkisuuntaisten profiilien säätämiseen ja kalanterointiin. Työn tavoitteena oli löytää syyt erään hienopaperikoneen heikkoon paksuusprofiiliin ja siitä aiheutuvaan suureen rullahylkymäärään. Syitä heikkoon paksuusprofiiliin on haettu kalanterin, päällystysasemien ja laatusäätöjärjestelmän toiminnoista. Työssä on tutkittu myös karheusprofiilin vaikutusta paksuusmittaukseen. Työssä löydettiin selvä yhteys paperin karheusprofiilin ja paperikoneen paksuusmittarin mittaaman paksuusprofiilin välille. Radan reuna-alueiden karheus suurentaa online-paksuusmittarin mittaustulosta. Karheusprofiili ei kuitenkaan vaikuta laboratoriomittareilla mitattuun paksuusprofiiliin. Paperikoneen onlinepaksuusmittarin mittausvirhe on kompensoitava, jotta paperin todellinen paksuusprofiili saadaan suoraksi. Työssä tehtyjen tutkimusten perusteella muodostettiin ajomalli, jolla ajettiin koeajojakso. Ajomallin päällimmäinen tarkoitus oli kompensoida paperikoneen online- paksuusmittarin mittausvirhe. Koeajo onnistui hyvin. Koeajojakson profiilivioista johtuva rullahylyn määräoli merkittävästi pienempi kuin referenssijakson profiilivioista johtuva rullahylyn määrä.

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Työn tavoitteena oli kuvata Artowood Oy:ssä toteutettu tuotannon kehittämishanke sekä arvioida sen nykyistä tuotantoa. Lisäksi käsiteltiin yrityksen asemaa alihankintayrityksenä. Teoriaosuudessa verrattiin eri tuotannonohjausteorioita, käsiteltiin tuotannon ajoitukseen liittyviä kysymyksiä sekä paneuduttiin tuotannon kehittämiseen ja laatuun. Johtopäätöksenä, kehitetty tuotannonohjausjärjestelmä on toimiva nykyisissä olosuhteissa, mutta yrityksen kasvaessaon kiinnitettävä enemmän huomiota tuotannon ajoitusongelmien hallintaan. Lisäksi tuotannon laatua on joka tapauksessa kehitettävä. Artowood Oy on käynnistänyt toimenpiteet oman suoran viennin aloittamiseksi, sillä kotimaan markkinat ovat epävakaat kausivaihteluiden ja kiristyneen kilpailun seurauksena. Vientiprojektinonnistuminen on tärkeää, sillä kotimaassa on liian vähän sellaisia asiakkaita, joilla on tarve Artowood Oy:n tuotantoteknologian kannalta riittävän suurille valmistuserille.