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Development of analysis methods for the assessment of hull girder loading and strength of a turret moored FPSOAryawan, Iwan Darajat January 2000 (has links)
No description available.
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Thread Drifting by Juvenile Bivalves in the Coos Bay Estuary, Oregon: Species Identification and the Influence of Estuarine Hydrodynamics and Diel MigrationDlouhy, Brittney, Dlouhy, Brittney January 2012 (has links)
From September 2009 to July 2011 I collected vertically stratified zooplankton samples and recorded estuarine water parameters on a monthly basis in the Coos Bay estuary, Oregon during flood and ebb tides. I identified five taxa of juvenile bivalves in the plankton:
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Foraging efficiencies on drifting and benthic prey in juvenile salmonids - effect of light / Födosökseffektivitet på driftande och bentiska byten hos juvenila laxfiskar - effekt av ljusLarsson, Pia L. M. January 2016 (has links)
Stream living salmonids are generally regarded as drift feeders that rely upon their vision when foraging. It has been shown that salmonids become nocturnal at low water temperatures, but have a low foraging efficiency as light intensity is low, due to their dependence upon vision. Shifting from drift feeding to benthic feeding, has been suggested, and analyses of gut contents during winter have shown that the diet of salmonids mainly consists of benthic invertebrates. Most experimental studies of salmonid foraging have only offered the fish drifting prey or only given the fish access to benthic prey in total darkness. Such conditions rarely occur in nature and the importance of benthic foraging to salmonids may therefore have been underestimated. In this study I conducted a stream laboratory experiment to test if low light intensity caused juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) (age 0+) to forage more on benthic than drifting prey. The salmon foraged on both drifting and benthic prey during high light but consumed only benthic prey during low light (by one of six fish). Trout foraged on both drifting and benthic prey during both high and low light, but foraging efficiency was lower during low than high light and foraging efficiency was lower for benthic prey than for drifting prey. These results indicate that both species forage more opportunistically than previously thought. / Strömlevande laxfiskar anses generellt vara driftätare som förlitar sig på synen när de födosöker. Det har visats att laxfiskar blir nattaktiva vid låga vattentemperaturer, men har en låg födosökseffektivitet då ljusintensiteten är låg, på grund av sitt beroende av synen. Skifte från driftätande till att äta bentiska byten, har föreslagits, och analyser av maginnehåll under vintern har visat att laxfiskars diet huvudsakligen består av bentiska evertebrater. De flesta experimentella studier av laxfiskars födosök har endast erbjudit fisken driftande byten eller endast gett fisken tillgång till bentiska byten vid totalt mörker. Sådana förhållanden förekommer sällan i naturen och betydelsen av bentiskt födosök för laxfiskar kan därför ha underskattats. I den här studien utförde jag ett experiment i en laboratorieström för att testa om låg ljusintensitet fick juvenil Atlantlax (Salmo salar) och öring (Salmo trutta) (ålder 0+) att födosöka mer på bentiska än driftande byten. Laxen födosökte på både driftande och bentiska byten vid högt ljus men bara bentiska byten åts vid lågt ljus (av en av sex fiskar). Öringen födosökte på både driftande och bentiska byten vid både hög och låg ljusintensitet, men födosökseffektiviteten var lägre vid låg än hög ljusintensitet och födosökseffektiviteten var lägre för bentiska än förbiflytande byten. Dessa resultat indikerar att båda arterna födosöker mer opportunistiskt än vad man tidigare ansett.
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Single Pulse Studies Of Wide Profile Drifting Pulsars - A Probe Of Pulsar MagnetospheresBhattacharyya, Bhaswati 09 1900 (has links)
The detailed nature of radio emission processes of pulsars and the exact location and distribution of the pulse emitting regions are still shrouded with mystery. Pulsars with drifting subpulses are considered as an important key for unlocking the mystery of how radio pulsars work. The phenomenon of subpulse drifting (first reported by Drake & Craft (1968)) is manifested as an organized subpulse behavior - subpulses appear at progressively changing longitude in the pulse window following some particular path. The path followed by the subpulses is specific to the individual pulsar concerned and is known as drift band. Drifting is generally characterized by Pm2(horizontal separation between the drift bands, i.e. in pulse longitude) and Pm3(vertical separation between the drift bands, i.e. in pulse numbers). The subpulse drifting phenomenon finds a natural explanation in the model of Ruderman & Sutherland (1975). According to this model, the subpulse drifting is produced from a system of sub-beams (subpulse associated plasma columns). Sparks (sparking discharges within the vacuum gap) rotating around the magnetic axis under the action of an E x B drift, give rise to a circulating pattern of sub-beams, and the time for one full circulation is referred to as the carousel rotation period, which we designate as P4. As pulsar radiation beams are widely believed to be arranged in concentric cones, it is natural to expect the circulating sparks to be distributed in annular rings on the polar cap. Each of these rings gives rise to one cone in the nested cones of emission. It has been recently shown that, subpulse drift may be fairly common among pulsars (Weltevrede et al. (2006) and (2007)). Hence, the pulsar radio emission mechanism is most likely closely connected with mechanism for drifting. In spite of significant progress both in high quality observations of drifting (e.g. Weltevrede et al. (2006) and (2007)) and attempts for confronting the results from the observations with existing models (e.g. Deshpande & Rankin (1999) and Gupta et al. (2004) etc), the pulsar emission mechanism is still an unsolved puzzle.
Backer (1970b) first reported that emission from certain pulsars abruptly switches off for several periods, and suddenly comes back. This phenomenon is known as nulling. Nulling appears to be random, broadband and intrinsic to the concerned pulsar. Nulling is quite common in pulsars (Biggs, 1992). Although different aspects of the phenomenon of nulling are investigated in detail for many pulsars by several authors using high sensitivity observations, nulling is not yet explained by the existing theoretical models for pulsar radio radiation.
In this thesis, I have mainly studied phenomenon of subpulse drifting and nulling, with the aim to probe the radio emission processes of pulsars. Most of the pulsars have a narrow duty cycle of emission (5-10 % of pulsar period). This is generally consistent with the expectations of the angular width of the polar cap, for typical viewing geometries. However, there are small but significant number of pulsars with unusually wide profiles where the emission is seen for a wide range of longitude (≥ 90 degrees). These are expected to be pulsars which are highly aligned, i.e. the magnetic dipole axis is almost parallel to the spin axis. In such a case, the line of sight (LOS) is very close to both the rotation and the magnetic axes, and consequently, we sample a large region of the polar cap. This has the exciting potential to allow a detailed study of the distribution and behavior of emission regions located in an annular ring around the magnetic axis. The study of pulsars showing systematic subpulse drift patterns provides important clues for the understanding of the unsolved problems of pulsar emission mechanism. Constraints provided by such observations can have far reaching implications for the theoretical models, as exemplified by some of the recent results in this area (e.g. Deshpande & Rankin (1999) and Gupta et al. (2004)). In this context, wide profile drifting pulsars can provide extra insights because of the presence of simultaneous multiple drift bands. During the thesis period, I have mainly concentrated on the study of single pulse properties of two wide profile drifting pulsars, PSR B0818-41 and PSR B0826-34.
In depth study of PSR B0818-41
We have studied single pulse properties of a relatively less studied wide profile pulsar, B0818-41 using highly sensitive multi-frequency observations with the GMRT in full polar mode. Detailed investigation of PSR B0818-41 are reported in Chapters 2, 3 and 4 of this thesis. New results from our study are described in the following.
We estimate the mean flux of PSR B0818-41 at 5 different frequencies and show that the spectrum flattens at frequencies lower than 325 MHz (at 244 or 157 MHz), providing indication of a low frequency turn-over.
Significant linear polarization is observed at 325, 610 and 1060 MHz. Average linear polarization falls off much faster than the total intensity and decreases to zero near the outer edge of the profile. This can be explained by the orthogonal polarization mode jump at the edges of the profile observed at 325 MHz. Polarization angle sweep across the pulse profile evolves remarkably with frequency (between 325, 610 and 1060 MHz), which is not generally observed in other pulsars. Very less circular polarization without any signature of changing handedness is observed at 325 and 610 MHz. But circular polarization changes sign at the middle of the pulse profile at 1060 MHz.
We report the discovery of a remarkable subpulse drift pattern in PSR B0818-41, using the high sensitivity GMRT observations. We find simultaneous occurrence of three drift regions with two different drift rates: an inner region with steeper apparent drift rate flanked on each side by a region of slower apparent drift rate.
The closely spaced drift bands always maintain a constant phase relationship: the subpulse emission from the inner drift region is in phase with that from the outer drift region on the right hand side, and at the same time the emission in the inner drift region is out of phase with the outer drift region situated on the left hand side. This phase locked relationship (hereafter PLR) is maintained for the entire stretch of the data (for all the epochs of observations at 325 and 610 MHz) and does not appear to get perturbed after intermittent nulling or during changes in the drift rate.
We observe frequent changes of drift rates. We see extreme examples of changing drift rates such as transitions from negative to stationary or stationary to negative drift rates, many of which appear to have some connection with nulls. We investigate changes in drift rates for about 10,000 pulses from two different epochs of observations at 325 MHz and observe frequent occurrences of small changes in the drift rate, seven transitions from negative to stationary drift rates, five transitions from stationary to negative drift rates, and two possible signatures of curved drift bands.
In addition to the remarkable subpulse drift observed at 325 MHz, we report subpulse drifting at 244 and 610 MHz. At 244 MHz subpulse drifting is observed only in the leading and trailing outer regions, but not in the inner region. Though the drift bands are weaker, subpulse drifting is observed in both inner and outer region at 610 MHz.
Pm2, Pm3 and ΔΦs(subpulse width) are determined for the inner and the outer drift regions for different frequencies. Though Pm3 is observed to be the same for the inner and outer drift regions, pm2 and ΔΦsare different for different drift regions.
The unique drift pattern of this pulsar can be naturally explained as being created by the intersection of our LOS with two conal rings on the polar cap of a fairly aligned rotator. Based on the frequency evolution of the average profile, observed polarization angle (PA) swing and results from subpulse drifting, we converged on two possible choices of emission geometry: G-1 (inclination angle α= 11 deg and impact angle β= -5.4 deg; which incidentally reproduces the middle part of the PA sweep at 610 MHz) and G-2 (α=175.4 deg and β=- 6.9 deg; geometry derived from RVM fit to 325 MHz PA sweep). Pulsar radiation pattern simulated with both the geometries reproduces the average profile as well as the observed features in the drift pattern quite well. However, G-2 fits the PA sweep much better.
We report that the peaks of the emission from the trailing and leading outer regions, as a function of the pulse number, are offset by a constant interval, P5~9P1. We also report a phase locked relation (PLR) between the inner and outer drift regions for PSR B0818-41. A new technique is introduced by us for resolving aliasing, using this constant offset (P5 ~ 9P1) between the peak emission from the leading and trailing outer regions. From the result of this technique, we propose that the subpulse drifting for PSR B0818 -41 is most likely first order aliased, and the corresponding carousel rotation period 4 =10 s. This implies that PSR B0818 -41 has the fastest known carousel.
The drift pattern in the inner and outer rings are always phase locked for PSR B0818 -41. This could be a significant constraint for the theoretical models of pulsar radio emission, and favors a pan magnetospheric emission mechanism.
We observe frequent nulling for PSR B0818-41. We calculate a nulling fraction ~30% at 325 MHz for this pulsar. Lengths of neighboring nulls and bursts are found to be independent.
For the inner drift region, our investigations bring out the fact that the nature of the transitions from burst to null are different from the transitions from null to burst. Switching off of pulsar radiation during nulling for PSR B0818 -41 is not abrupt, but is gradual, whereas the transitions from null to burst are found to be rather abrupt for the inner drift region. This effect is not prominent in the outer drift regions. Although, the inner region of the last active pulses before nulls are dimmer, the first active pulses after nulls outshines the normal ones.
The intensity of the inner region is maximum for the average profile from the first active pulse immediately after the nulls and then gradually goes down. This is consistent with the behavior of the individual nulls described above. However, this is not the case for the leading and trailing outer regions.
The average profiles from the first active pulse immediately after the nulls follows similar shape as the normal profile but shows an increased intensity (in the form of a bump) in the inner region which is not present in the normal average profile. In addition, the leading and the trailing peaks appear to be of similar intensity, while trailing peak is significantly more intense for the normal profile. The average profiles from the pulses immediately after the nulls are wider than the normal profile.
The average profiles of the first active pulses after the nulls are drastically similar between two epochs of observations. This is a very unique result which is not reported for any other pulsar so far and may imply that the phenomenon of nulling is associated with some systematic energy re-distribution in the pulsar magnetosphere.
In depth study of PSR B0826-34
PSR B0826-34 is a pulsar with one of the widest known profile. The earlier studies of this pulsar (Durdin et al. (1979), Biggs et al. (1985) and Gupta et al. (2004)) have brought out some unique properties : strong evolution of the average profile with frequency, apparent nulling for 70% of time and a remarkable subpulse drift property- multiple curved drift bands with frequent changes and sign reversals of drift rate. We studied PSR B0826 -34 using the GMRT, simultaneously at 303 and 610 MHz, and individually at 157, 325, 610 and 1060 MHz. Detailed investigation of PSR B0826- 34 are reported in Chapter 5 of this thesis. Some of the interesting new results from our work are,
As a natural out-come of the simultaneous dual frequency observations, we obtain an accurate DM value, equal to 52.2(6) pc/cm3, for this pulsar. Unlike most normal pulsars the DM determination for this pulsar is a difficult and trick exercise, mainly because the profile is quite complex, very wide and strongly evolving with frequency. The advantage of our method of DM determination is that the observations at a single epoch are self sufficient for obtaining the DM value at that epoch.
Contrary to the earlier study by Esamdin et al. (2005), we find no evidence of weak emission during the typical long null states of this pulsar, simultaneously at 303 and 610 MHz, as well as from non simultaneous observations at 157, 325, 610 and 1060 MHz at separate epochs. We have also obtained absolute flux limits for the non-detection at various frequencies, which should be a useful comparison standard for any more sensitive studies in the future.
We present the average profiles at five different frequencies. Main pulse (MP) and inter pulse (IP) emission observed for this pulsar span over wide pulse longitude. There is a remarkable frequency-evolution of pulse profile: IP becomes stronger with increasing frequency.
We estimated the mean flux of the MP, IP and the full pulse region of PSR B0826- 34 at different frequencies of observation.
Significant correlation in the total intensity of the individual pulses between 303 and 610 MHz is reported from the simultaneous dual frequency observations, which is indicative of the broad-band nature of the emission. The intensity correlations are positive for large lags, indicating that there is some kind of memory in the underlying structure. This memory is the longest for PSR B0826- 34, amongst all known cases.
Our study of this pulsar brings out insight into simultaneous behavior of the single pulses from PSR B0826- 34 at 303 and 610 MHz, which has not been examined so far. We see about 6 -7 drift bands in the MP region at 303 and at 610 MHz. At 610 MHz we see about 2 -3 drift bands in the IP region. We observe wide variations in the drift rates, including positive and negative drift rates and curved drift bands, which are simultaneous for both frequencies. We have noticed coherence between simultaneous multiple drift bands - at some given instant of time all the drift bands (6 -7 drift bands) under the MP window show similar kind of drift.
Though we find the drift pattern to be very similar in the simultaneous 303 and 610 MHz data, we observe that the drift band separation (Pm2) evolves significantly between these two frequencies, and in a manner opposite to the average profile evolution. In addition, we confirm the dependence of Pm2 on pulse longitude at 303 MHz and find indications for the same at 610 MHz.
Significant linear polarization is observed in the MP region which drops abruptly at the edges of the pulse profile. Two orthogonal mode jumps are seen at the edges of the MP for both 325 and 610 MHz. We observe somewhat non orthogonal mode jump at the edges of IP for 610 MHz. Significant circular polarization in the MP along with the sense reversal near the center is observed for both the frequencies. The PA curve shows typical ”S” shaped swing (though there is some hint of a kink in the central part of the PA curve). RVM fit (Radhakrishnan & Cooke, 1969) to the PA curve is obtained with α~ 9.8 deg, β~3.2 deg, at both 325 and 610 MHz.
The detailed study of two unique wide profile pulsars, PSR B0818-41 and PSR B0826 -34, was very rewarding and provided fair amount of insight towards the emission properties of pulsars. We broadly conclude that the emission from simultaneous multiple drift bands are coherent. In other words the emission mechanism responsible for generation of the drift bands is heavily correlated in the whole on pulse window. Also the equispaced sparks argues for a more isotropic arrangement of sparks which is favored by the conal model (Rankin, 1983). Drifting from more than one rings are observed only for two pulsars, PSR B0818-41 and PSR B0826-34. For PSR B081841 we observe that the emission from different rings are always locked in phase. This constant phase relation is maintained even during sequences of irregular drifting as well as after nulling. PSR B0826 -34 is another wide profile pulsar for which presence of simultaneous multiple drift regions are observed. For this pulsar the MP and the IP emission are interpreted to be coming from two concentric rings of emission. The drift bands in these regions are locked in phase implying that the emission from the inner and the outer rings are in phase. For PSR B0826- 34 we observe frequent nulling and changes of drift rates which are simultaneous for both the inner and outer rings. Hence for all pulsars for which we know drifting from more than one ring, the drift pattern in the inner and outer rings are always phase locked. No counter example is observed. This requires common drift rate in the inner and outer rings, implying that emission in the two rings are not independent, and the conditions responsible for drifting are similar in both rings. Our finding of PLR between the emission from the inner and the outer rings puts constraints on the theoretical models of pulsar emission mechanism and favors a pan magnetospeheric radiation mechanism.
Preliminary study of single pulse properties of six other pulsars
Inspired by the success of our study of PSR B0818- 41 and PSR B0826-34 we carried out single pulse study of few other pulsars with diverse profile. Preliminary results from this study are presented in Chapter 6. However, some of the new results form this work are highlighted in the following. We report occasional nulling for PSR B0540+23 which is important in the sense that nulls are not commonly seen in the core components. We observe simultaneous two drift bands for B1819- 22 at 325 and 610 MHz. We observe some kind of mode changing between stronger and weaker modes with changes of drift rates, which are probably associated with occasional nulling observed in this pulsar. For PSR B1839 -04 subpulse drifting is observed under the two peaks of the profile. The emission under the leading and trailing peaks appear to be in phase.
Determination of the orbital parameters of binary pulsars
Apart from the above work, I got interested in determination of the orbital parameters of the binary pulsars. This work was triggered by the discovery of a binary pulsar PSR J0514- 4002 (the first known pulsar in the globular cluster NGC 1851) at the GMRT in 2004 (Freire et al., 2004). We present a novel method for determination of the orbital parameters of binary pulsars, using data on the pulsar period at multiple observing epochs in contrast to the method described by Freire, Kramer & Lyne (2001) which requires both pulsar period and period derivatives at particular observing epochs. This method uses the circular nature of the velocity space orbit of Keplerian motion and produces preliminary values based on two one dimensional searches. Preliminary orbital parameter values are then refined using a computationally efficient linear least square fit. This method works for random and sparse sampling of the binary orbit. Unlike the method used by Freire, Kramer & Lyne (2001), which works for nearly circular binary orbits, this method works for binary orbit with any eccentricity. We demonstrate the technique on (a) the highly eccentric binary pulsar PSR J0514- 4002 (the first known pulsar in the globular cluster NGC 1851) and (b) 47 Tuc T, a binary pulsar with a nearly circular orbit. Our result agrees with the earlier determination of the orbital parameters of the binary pulsars done with coherent multi-epoch timing (Freire, Kramer & Lyne (2001) and Freire et al. (2007)). In our method the computation involves only one dimensional searches and linear least square fits. This study is reported in Chapter 7.
The main conclusions and the possible future works are presented in Chapter 8.
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Vilka anpassningar av target costing har Ericsson Power Modules AB valt att göra?Barthel, Fredrik, Österberg, Emmelie January 2008 (has links)
<p>Sammanfattning</p><p>Datum:2008-06-15</p><p>Nivå: Magisteruppsats i företagsekonomi, 15 hp</p><p>Författare: Fredrik Barthel Emmelie Österberg</p><p>Eskilstuna Västerås</p><p>Handledare: Esbjörn Segelod</p><p>Titel: Vilka anpassningar av target costing har Ericsson Power Modules</p><p>AB valt att göra?</p><p>Problem: Den ökande globaliseringen har lett till att konkurrensen har ökat.</p><p>Detta ställer högre krav på företagen att minska kostnaderna. Då är</p><p>target costing en möjlighet att kostnadsminimera.</p><p>Syfte: Syftet med uppsatsen är att jämföra teoretisk referensram med</p><p>empiri från Ericsson Power Modules AB för att visa på hur olika</p><p>faktorer kan påverka och styr arbetet med target costing.</p><p>Metod: Metoder som används för denna uppsats är litteratursökning och</p><p>telefonintervjuer. Litteratursökningen valdes för att få den</p><p>teoretiska referensramen och sökorden för detta var target costing.</p><p>Resultat: Uppsatsförfattarna har funnit ett antal olika faktorer som påverkar</p><p>Ericsson Power Modules AB:s sätt att arbeta med target costing.</p><p>De påverkande faktorerna är produkten, komponenterna, lönerna</p><p>och konstruktionstiden. Däremot har det inte kunnat påvisas att det</p><p>skulle vara några kulturella betingelser som styr.</p>
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Vilka anpassningar av target costing har Ericsson Power Modules AB valt att göra?Barthel, Fredrik, Österberg, Emmelie January 2008 (has links)
Sammanfattning Datum:2008-06-15 Nivå: Magisteruppsats i företagsekonomi, 15 hp Författare: Fredrik Barthel Emmelie Österberg Eskilstuna Västerås Handledare: Esbjörn Segelod Titel: Vilka anpassningar av target costing har Ericsson Power Modules AB valt att göra? Problem: Den ökande globaliseringen har lett till att konkurrensen har ökat. Detta ställer högre krav på företagen att minska kostnaderna. Då är target costing en möjlighet att kostnadsminimera. Syfte: Syftet med uppsatsen är att jämföra teoretisk referensram med empiri från Ericsson Power Modules AB för att visa på hur olika faktorer kan påverka och styr arbetet med target costing. Metod: Metoder som används för denna uppsats är litteratursökning och telefonintervjuer. Litteratursökningen valdes för att få den teoretiska referensramen och sökorden för detta var target costing. Resultat: Uppsatsförfattarna har funnit ett antal olika faktorer som påverkar Ericsson Power Modules AB:s sätt att arbeta med target costing. De påverkande faktorerna är produkten, komponenterna, lönerna och konstruktionstiden. Däremot har det inte kunnat påvisas att det skulle vara några kulturella betingelser som styr.
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Observations et modélisation de la neige soufflée en Antarctique / Observations and modelisation of blowing and drifting snow over AntarcticaTrouvilliez, Alexandre 14 October 2013 (has links)
L'augmentation de l'accumulation de neige simulée en Antarctique de l'Est pour le siècle à venir est une contribution négative à la hausse du niveau moyen des mers. Les modèles climatiques simulant cette augmentation ne possèdent pas de paramétrisation du transport éolien de neige or ce dernier joue un rôle primordial sur l'accumulation d'après les observations. Les modèles climatiques régionaux possédant une paramétrisation du transport éolien permettent d'estimer l'incertitude des modèles climatiques sur la hausse du niveau moyen des mers en ne représentant pas ce processus. Cependant aucune donnée de transport ne permet une validation précise de ces modèles en Antarctique. Dans ce contexte, cette thèse décrit la constitution d'une base de données de transport éolien de neige en Antarctique ainsi qu'une validation d'un modèle climatique régional incluant le transport éolien de neige. Un instrument acoustique, le FlowCapt, a été choisi pour acquérir les données. Une comparaison avec un appareil de mesure optique du transport, le Snow Particle Counter, a été menée dans les Alpes françaises. Cette comparaison a permis de déterminer les limites des deux générations de FlowCapt existantes pour la détection des événements de transport et la quantification du flux de neige. Une base de données de trois années a été acquise en Terre Adélie, Antarctique, pour permettre une comparaison avec un modèle climatique régional. Elle a permis de calculer la hauteur de rugosité et la vitesse de frottement seuil avec leurs incertitudes. Les épisodes de transport éolien de neige et une borne inférieure de la quantité de neige déplacée en un point ont été estimés. Deux comparaisons ont été menées avec le Modèle Atmosphérique Régional, un modèle climatique régional incluant de nombreuses rétroactions du transport sur l'écoulement. Les deux simulations utilisées pour les comparaisons ont été faites sur un petit domaine à fine échelle sur une période d'un mois. Le modèle simule bien les épisodes de transport sauf lorsque de la fonte s'est produite juste avant un épisode ou lorsque les épisodes ont une hauteur maximale de transport inférieure à cinquante centimètres. Le modèle sous-estime les quantités de neige transportée. / Predicted accumulation by global numerical climate models for the next century increases in East Antarctica and negatively contributes to the mean sea level rise. None of the climate models integrates a blowing snow parametrisation. However few smaller scale regional climate models include a blowing snow parametrisation and thus can assess the climate models uncertainty on the mean sea level rise by not representing this process. Yet none of the blowing snow data available in Antarctica allows for a precise validation of a regional climate model. In this context, this PhD described the establishment of an Antarctica blowing snow database and the validation of a regional climate model including a blowing snow parametrisation. An acoustic blowing snow sensor, the FlowCapt, has been chosen to collect data in Antarctica. A comparison with an optic blowing snow sensor, the Snow Particle Counter, has been conducted in the French Alps. The capacity of the two existing FlowCapt generation has been determined on the blowing snow event and the flux quantification. A three years blowing snow model-oriented database is now available in Adélie Land, Antarctica. The threshold friction velocity and the roughness height have been calculated with their uncertainty. Blowing snow variability has been determined as well as the minimum transport rate at one field point. Two comparisons have been done with the Modèle Atmosphérique Regional (MAR), a regional climate model including a blowing snow parametrisation. Both simulations represent a small domain with a high vertical and horizontal resolution over one month. The model is able to reproduce the blowing snow event except when melting occurs or when the blowing snow height is encompassed within the first fifty centimetres above the ground. The model underestimate the snow quantity transported at the field measurement point.
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Sistemas de gestão empresarial : compreendendo o processo de implementação e identificando o drifting através da interação de atoresCanepa, Paola Carmen Valenzuela January 2010 (has links)
Existem diversas pesquisas que tratam o assunto do processo de implementação dos Sistemas de Gestão Empresarial (SGE) no setor empresarial. A maioria delas focalizada no planejamento e o controle do gerenciamento no contexto formativo e abrangente que as envolve. Contudo, ainda existe uma lacuna ao estudar o processo de implementação nas pequenas e médias empresas que tenham orientação empreendedora. Devido ao fato de que estas empresas encontram-se num ambiente descontrolado, evidenciando saídas de rumo diante qualquer planejamento (drifting), tornam-se interessante os estudos de caso neste setor. Sendo assim, compreender como acontece o processo de implementação de um SGE e quais são as práticas que podem ser executadas para promover sua utilização sucedida é o foco deste trabalho de pesquisa. Para tanto foram utilizados os conceitos teóricos trazidos pelo trabalho de Ciborra (2002, 2000, 1999) em conjunto com a abordagem da Teoria do Ator- Rede (TAR) proposta pelo Latour (2005), Callon (1998) e Law (1992). O trabalho mostra a forma de utilização da TAR, evidencia os conceitos trazidos pelo Ciborra (2002, 2000, 1999) e propõe práticas para promover a utilização dos SGE para a fornecedora do estudo. Além disso, demonstra a necessidade de fazer mais pesquisas, no setor empresarial objeto deste estudo, uma vez que este tipo de empresa não aplica as melhores práticas mostradas nas diversas pesquisas apresentadas na literatura. Assim também, sugere-se a continuação deste estudo analisando outros atores que introduzam o ambiente tecnológico, econômico e social desse setor para poder identificar outros motivos pelos quais os atores executaram e fizeram as escolhas relatadas, pois com a TAR estudou-se a interação entre os atores envolvidos no processo de implementação do SGE, apresentando uma descrição de como foi construído esse processo. / There are several researches that deal with the matter of ERP implementation process on enterprise sector. Most of them focused on planning management control on overarching formative context that involves them. However, there is still a gap when a study is made on implementation for small and medium sized companies with entrepreneur orientation. Because these companies are settled in a non-controlled environment, noticing miss-routing upon any planning (drifting), it is interesting to have case studies in this sector. Thus, understanding how ERP implementation process is made and which are the procedures that can be applied to promote a succeed utilization is the focus of this research work. For this, it has been used theorical concepts brought by the work of Ciborra (2002, 2000, 1999) and the theorical approach of actor-network theory (ANT) proposed by Latour (2005), Callon (1998) and Law (1992). This work has shown the utilization of the ANT, it has evidenced the concepts brought by Ciborra (2002, 2000, and 1999) and suggests practices to promote the utilization of ERP for the supplier followed on this study. Besides, it is suggested to continue this study by introducing actors that represents the technological, economical and social environment of the studied sector to identify others reasons for actors’ options, once with the ANT was shown the interaction between the actors during the implementation process as a description of how the process was constructed as a result of this interaction.
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Sistemas de gestão empresarial : compreendendo o processo de implementação e identificando o drifting através da interação de atoresCanepa, Paola Carmen Valenzuela January 2010 (has links)
Existem diversas pesquisas que tratam o assunto do processo de implementação dos Sistemas de Gestão Empresarial (SGE) no setor empresarial. A maioria delas focalizada no planejamento e o controle do gerenciamento no contexto formativo e abrangente que as envolve. Contudo, ainda existe uma lacuna ao estudar o processo de implementação nas pequenas e médias empresas que tenham orientação empreendedora. Devido ao fato de que estas empresas encontram-se num ambiente descontrolado, evidenciando saídas de rumo diante qualquer planejamento (drifting), tornam-se interessante os estudos de caso neste setor. Sendo assim, compreender como acontece o processo de implementação de um SGE e quais são as práticas que podem ser executadas para promover sua utilização sucedida é o foco deste trabalho de pesquisa. Para tanto foram utilizados os conceitos teóricos trazidos pelo trabalho de Ciborra (2002, 2000, 1999) em conjunto com a abordagem da Teoria do Ator- Rede (TAR) proposta pelo Latour (2005), Callon (1998) e Law (1992). O trabalho mostra a forma de utilização da TAR, evidencia os conceitos trazidos pelo Ciborra (2002, 2000, 1999) e propõe práticas para promover a utilização dos SGE para a fornecedora do estudo. Além disso, demonstra a necessidade de fazer mais pesquisas, no setor empresarial objeto deste estudo, uma vez que este tipo de empresa não aplica as melhores práticas mostradas nas diversas pesquisas apresentadas na literatura. Assim também, sugere-se a continuação deste estudo analisando outros atores que introduzam o ambiente tecnológico, econômico e social desse setor para poder identificar outros motivos pelos quais os atores executaram e fizeram as escolhas relatadas, pois com a TAR estudou-se a interação entre os atores envolvidos no processo de implementação do SGE, apresentando uma descrição de como foi construído esse processo. / There are several researches that deal with the matter of ERP implementation process on enterprise sector. Most of them focused on planning management control on overarching formative context that involves them. However, there is still a gap when a study is made on implementation for small and medium sized companies with entrepreneur orientation. Because these companies are settled in a non-controlled environment, noticing miss-routing upon any planning (drifting), it is interesting to have case studies in this sector. Thus, understanding how ERP implementation process is made and which are the procedures that can be applied to promote a succeed utilization is the focus of this research work. For this, it has been used theorical concepts brought by the work of Ciborra (2002, 2000, 1999) and the theorical approach of actor-network theory (ANT) proposed by Latour (2005), Callon (1998) and Law (1992). This work has shown the utilization of the ANT, it has evidenced the concepts brought by Ciborra (2002, 2000, and 1999) and suggests practices to promote the utilization of ERP for the supplier followed on this study. Besides, it is suggested to continue this study by introducing actors that represents the technological, economical and social environment of the studied sector to identify others reasons for actors’ options, once with the ANT was shown the interaction between the actors during the implementation process as a description of how the process was constructed as a result of this interaction.
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Sistemas de gestão empresarial : compreendendo o processo de implementação e identificando o drifting através da interação de atoresCanepa, Paola Carmen Valenzuela January 2010 (has links)
Existem diversas pesquisas que tratam o assunto do processo de implementação dos Sistemas de Gestão Empresarial (SGE) no setor empresarial. A maioria delas focalizada no planejamento e o controle do gerenciamento no contexto formativo e abrangente que as envolve. Contudo, ainda existe uma lacuna ao estudar o processo de implementação nas pequenas e médias empresas que tenham orientação empreendedora. Devido ao fato de que estas empresas encontram-se num ambiente descontrolado, evidenciando saídas de rumo diante qualquer planejamento (drifting), tornam-se interessante os estudos de caso neste setor. Sendo assim, compreender como acontece o processo de implementação de um SGE e quais são as práticas que podem ser executadas para promover sua utilização sucedida é o foco deste trabalho de pesquisa. Para tanto foram utilizados os conceitos teóricos trazidos pelo trabalho de Ciborra (2002, 2000, 1999) em conjunto com a abordagem da Teoria do Ator- Rede (TAR) proposta pelo Latour (2005), Callon (1998) e Law (1992). O trabalho mostra a forma de utilização da TAR, evidencia os conceitos trazidos pelo Ciborra (2002, 2000, 1999) e propõe práticas para promover a utilização dos SGE para a fornecedora do estudo. Além disso, demonstra a necessidade de fazer mais pesquisas, no setor empresarial objeto deste estudo, uma vez que este tipo de empresa não aplica as melhores práticas mostradas nas diversas pesquisas apresentadas na literatura. Assim também, sugere-se a continuação deste estudo analisando outros atores que introduzam o ambiente tecnológico, econômico e social desse setor para poder identificar outros motivos pelos quais os atores executaram e fizeram as escolhas relatadas, pois com a TAR estudou-se a interação entre os atores envolvidos no processo de implementação do SGE, apresentando uma descrição de como foi construído esse processo. / There are several researches that deal with the matter of ERP implementation process on enterprise sector. Most of them focused on planning management control on overarching formative context that involves them. However, there is still a gap when a study is made on implementation for small and medium sized companies with entrepreneur orientation. Because these companies are settled in a non-controlled environment, noticing miss-routing upon any planning (drifting), it is interesting to have case studies in this sector. Thus, understanding how ERP implementation process is made and which are the procedures that can be applied to promote a succeed utilization is the focus of this research work. For this, it has been used theorical concepts brought by the work of Ciborra (2002, 2000, 1999) and the theorical approach of actor-network theory (ANT) proposed by Latour (2005), Callon (1998) and Law (1992). This work has shown the utilization of the ANT, it has evidenced the concepts brought by Ciborra (2002, 2000, and 1999) and suggests practices to promote the utilization of ERP for the supplier followed on this study. Besides, it is suggested to continue this study by introducing actors that represents the technological, economical and social environment of the studied sector to identify others reasons for actors’ options, once with the ANT was shown the interaction between the actors during the implementation process as a description of how the process was constructed as a result of this interaction.
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