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Scale model validation of QUAYSIM and WAVESCAT numerical models of ship motionsEigelaar, Lerika Susan 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Various numerical modelling software packages are available for predicting moored ship motions
and forces. The focus of this study was to validate the numerical models QUAYSIM and
WAVESCAT and how these models together form a procedure for predicting moored ship motions
and forces under the impact of high and low frequency waves.
The validation procedure applied in the study involved numerical modelling of a given physical
model situation in which moored ship motions and forces were measured under both high and low
frequency wave conditions. A physical model with built-in bathymetry was provided by the Council
for Scientific and Industrial Research (CSIR) Hydraulics Laboratory in Stellenbosch. The model
consisted of a moored container vessel at a jetty, with various mooring lines and fenders. A
JONSWAP spectrum, which combines high and low frequency wave components, was used to
simulate wave conditions for the modelling of ship motions. The wave periods and wave heights
were measured at observation stations located at specific points in the basin. Other measurements
such as those of the forces in the fenders and mooring lines were also determined.
A multi-step approach was used to numerically predict the ship motions and forces. Firstly, the
coastal processes occurring within the basin, which was set up to simulate the physical model
wave behaviour, were measured to calibrate the SWAN Delft3D-WAVE model. The wave heights
and periods for the respective observation stations were obtained and compared to the physical
model measurements. The Delft3D-FLOW SURFBEAT model was used to calculate the low
frequency waves in the coastal area. Low frequency waves are the main cause of larger ship
motions and forces, therefore it is important to investigate them as part of the ship motion
prediction procedure.
After the waves had been computed, wave forces acting on the vessel needed to be determined
for both high and low frequency waves. These wave forces were modelled with the combinations
SURFBEAT/LF-STRIP (low frequency waves) and SWAN/WAVESCAT (high frequency waves).
LF-STRIP provided the link between low frequency wave models and ship motion models,
converting the low frequency waves into long wave forces acting on the vessel. WAVESCAT
converted the high frequency waves to short wave forces. The calculated long wave forces and
short wave forces served as the input required to run the ship motion model QUAYSIM to
determine the movements of the moored ship as well as the restraining forces in the lines and
fenders. The ship motions and forces were compared to the physical model, with the intention of possibly validating the QUAYSIM/WAVESCAT approach for predicting moored ship motions.
The study provides an overview of both the setup and results of the physical and numerical model.
A description of each of the numerical models SWAN, SURFBEAT, LF-STRIP, WAVESCAT and QUAYSIM is provided, along with a comparison between the physical and numerical models for
each procedure. The validation procedure provided useful documentation of the quality of these
numerical modelling approaches, already in use in some design projects.
The numerical models WAVESCAT and QUAYSIM models of ship motion have shown to provide a
good correlation between the physical model and the numerical approach. However, improvements
are still required. Good comparisons were obtained for the long wave motions (horizontal
movements - surge, sway and yaw). The surge and sway motions were slightly overestimated by
QUAYSIM. The magnitude of the yaw was comparable but the not well represented in spectral plots. / AFRIKAANSE OPSOMMING: Daar is verskeie numeriese modellering-sagtewareprogramme beskikbaar waarmee
skipbewegings en -kragte voorspel kan word. Die fokus van hierdie studie was om die numeriese
modelle QUAYSIM en WAVESCAT te valideer. Saam vorm hierdie twee modelle ’n prosedure om
vasgemeerde skipbewegings en -kragte veroorsaak deur lang- en kortgolfaksie te bepaal.
Die validasieprosedure wat in hierdie studie gebruik is, behels ’n numeriese modelering van ’n
fisiese situasie waar ’n vasgemeerde skip se bewegings en kragte onder kort- en langgolfkondisies
gemeet is. ’n Fisiese model met ingeboude batimetrie is voorsien deur die Council for Scientific
and Industrial Research (CSIR) se hidroliese laboratorium in Stellenbosch. Die model bestaan uit
’n vasgemeerde houerskip by ’n pier met verskeie ankerlyne en bootbuffers. ’n JONSWAPspektrum,
wat kort- en langgolfkomponente kombineer, is gebruik om golfomstandighede vir die
modellering van skipbewegings te simuleer. Golfperiodes en golfhoogtes is by spesifieke
waarnemingstasies in die gesimuleerde hawe-area gemeet. Verdere opmetings, soos dié van die
kragte in die bootbuffers en ankerlyne, is ook gedoen.
’n Stap-vir-stap benadering is gevolg om die skipbewegings numeries te voorspel. Eerstens is die
kusprosesse wat in die gesimuleerde hawe plaasvind, gekalibreer met die numeriese paket SWAN
Delft3D-WAVE. Die golfhoogtes en golfperiodes vir elke waarnemingstasie is bereken en vergelyk
met die fisiese model se opmetings. Die SURFBEAT-module van Delft3D-FLOW is gebruik om die
lae-frekwensie golwe in die kusarea te bereken. Lae-frekwensie golwe is die hoofoorsaak van
skipbewegings en daarom is dit belangrik om dit te ondersoek gedurende die
voorspellingsprosedure van skipbewegings.
Na die golwe bereken is, moes die kragte wat beide kort en lang golwe op die skip uitoefen ook
bereken word. Hierdie golfkragte is gemodelleer deur middel van die kombinasies SURFBEAT/LFSTRIP
(langgolwe) en SWAN/WAVESCAT (kortgolwe). LF-STRIP het die skakel tussen
golfmodelle en skipbewegingsmodelle verskaf en die lae-frekwensie golwe omgeskakel in
langgolfkragte wat op die skip uitgeoefen is. WAVESCAT het die hoë-frekwensiegolwe
omgeskakel in kortgolfkragte wat op die skip uitgeoefen is. Die berekende langgolf- en
kortgolfkragte is ingevoer op die skipbewegingsmodel QUAYSIM om die skipbewegings en
inperkingskragte in die bootbuffers en ankerlyne te bepaal sodat dit vergelyk kon word met die
fisiese model, met die doel om moontlik die QUAYSIM/WAVESCAT-prosedure om gemeerde
skipbewegings te voorspel te valideer.
Die studie verskaf ’n oorsig van die opstel en resultate van die fisiese en numeriese modelle. Elk
van die numeriese modelle SWAN, SURFBEAT, LF-STRIP, WAVESCAT en QUAYSIM word
beskryf en vergelykings word getref tussen die numeriese en fisiese modelle vir elke prosedure. Die validasieprosedure verskaf nuttige dokumentasie van die kwaliteit van hierdie numeriese
modeleringsprosedures wat reeds in sekere ontwerpprojekte gebruik word.
Die numeriese WAVESCAT en QUAYSIM modelle van skipbewegings het ’n goeie korrelasie
tussen die fisiese model en die numeriese benadering gelewer. Verbeteringe is wel steeds nodig.
Goeie vergelykings is verkry vir langgolfbewegings (horisontale bewegings – stuwing (“surge”),
swaai (“sway”) en gier (“yaw”)). Die stu- en swaaibewegings was effens oorskat met QUAYSIM.
Die grootte van die gier was wel vergelykbaar maar is nie grafies goed uitgebeeld nie.
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Effekterna av en kort färdighetsträning i valideringsteknik för läkarstudenter / The Effects of a Short Training in Validation Technique for Medical StudentsBraide, Lisa, Nilsson, Emma January 2015 (has links)
No description available.
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Dutch translation and cross-cultural validation of the Adult Social Care Outcomes Toolkit (ASCOT)van Leeuwen, Karen, Bosmans, Judith E., Jansen, Aaltje PD, Rand, Stacey E., Towers, Ann-Marie, Smith, Nick, Razik, Kamilla, Trukeschitz, Birgit, van Tulder, Maurits W, van der Horst, Henriette E., Ostelo, Raymond January 2015 (has links) (PDF)
Background: The Adult Social Care Outcomes Toolkit was developed to measure outcomes of social care in
England. In this study, we translated the four level self-completion version (SCT-4) of the ASCOT for use in the
Netherlands and performed a cross-cultural validation.
Methods: The ASCOT SCT-4 was translated into Dutch following international guidelines, including two forward
and back translations. The resulting version was pilot tested among frail older adults using think-aloud interviews.
Furthermore, using a subsample of the Dutch ACT-study, we investigated test-retest reliability and construct validity
and compared response distributions with data from a comparable English study.
Results: The pilot tests showed that translated items were in general understood as intended, that most items
were reliable, and that the response distributions of the Dutch translation and associations with other measures
were comparable to the original English version. Based on the results of the pilot tests, some small modifications
and a revision of the Dignity items were proposed for the final translation, which were approved by the ASCOT
development team. The complete original English version and the final Dutch translation can be obtained after
registration on the ASCOT website (http://www.pssru.ac.uk/ascot).
Conclusions: This study provides preliminary evidence that the Dutch translation of the ASCOT is valid, reliable and
comparable to the original English version. We recommend further research to confirm the validity of the modified
Dutch ASCOT translation. (authors' abstract)
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Modelling transport, accessibility and productivity in ÖresundPetersen, Tom January 2004 (has links)
<p>This licentiate thesis is about the provision of transportinfrastructure and the regional impacts of such provision.Three different techniques have been investigated that can beused for the assessment and forecasting of the effects ofinfrastructure: transport demand models and parametric andnon-parametric econometric estimation techniques. The maininterest is focused around the regional effects of theÖresund fixed link, which was opened on July 1, 2000.</p><p>The thesis is a collection of three papers plus a generalintroduction: papers 1 and 2 are concerned with the effect ofaccessibility in the transport networks on productivity on anindividual firm level. In paper 1, a translog cost function,extended with an accessibility variable, is estimated for 24business aggregates using panel data techniques and tests on adataset covering single workplaces in Scania over the years199098. The results are not conclusive, and cannot beused for forecasting of the after-situation. In paper 2, anon-parametric method, propensity score matching, is applied onthe same dataset to test if productivity differs in highaccessibiliby areas compared to those with low accessibility,while controlling for other differences between firms. Theresult here is the same as in the first paper: for no businessthere is a significant difference in productivity that can berelated to accessibility. In paper 3, a framework for theexternal validation of models of transport, landuse andenvironment is developed, with a focus on transport forecastmodels. The scenario assumptions and forecast results ofearlier models are presented and compared. A before-and-afterdatabase under construction for the Öresund region is alsopresented, to be used for validation of such models.</p><p><b>Key words:</b>infrastructure assessment, validation,Öresund, transport demand models, regionalconsequences.</p>
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Infrared Reflection-Absorption Spectrometry and Chemometrics for Quantitative Analysis of Trace Pharmaceuticals on SurfacesPerston, Benjamin Blair January 2006 (has links)
Cleaning validation, in which cleaned surfaces are analysed for residual material, is an important process in pharmaceutical manufacturing and research facilities. Current procedures usually consist of either swab or rinse-water sampling followed by analysis of the samples. The analysis step is typically either rapid but unselective (conductivity, pH, total organic carbon, etc.), or selective but time-consuming (HPLC). This thesis describes the development of an in situ surface-spectroscopic analysis that removes the need for swab sampling and is both rapid and selective. This method has the potential to complement existing analyses to increase the efficiency of cleaning-validation protocols. The spectrometric system consists of a Fourier-transform infrared (FTIR) spectrometer coupled to a fibre-optic grazing-angle reflectance probe, and allows the measurement of infrared reflection-absorbance spectra (IRRAS) from flat surfaces in ~10 s. Multivariate chemometric methods, such as partial least squares (PLS) regression, are used to exploit the high information content of infrared spectra to obtain selective analyses without physical separation of the analyte or analytes from whatever interfering species may be present. Multivariate chemometric models require considerably more effort for calibration and validation than do traditional univariate techniques. This thesis details suitable methods for preparing calibration standards by aerosol deposition, optimising and validating the model by cross- and test-set validation, and estimating the uncertainty by resampling and formula-based approaches. Successful calibration models were demonstrated for residues of acetaminophen, a model active pharmaceutical ingredient (API), on glass surfaces. The root-mean-square error of prediction (RMSEP) was ~0.07 µg cm⁻². Simultaneous calibration for acetaminophen and aspirin, another API, gave a similar RMSEP of 0.06 µg cm⁻² for both compounds, demonstrating the selectivity of the method. These values correspond to detection limits of ~0.2 µg cm⁻², well below the accepted visual detection limit of ~1-4 µg cm⁻². The sensitivity of the method with a stainless steel substrate was found to depend strongly on the surface finish, with highly polished surfaces giving more intense IRRAS. RMSEP values of 0.04- 0.05 µg cm⁻² were obtained for acetaminophen on stainless steel with three different finishes. For this system, severe nonlinearity was encountered for loadings 1.0 µg cm⁻². From the results presented in this thesis, it is clear that IRRAS has potential utility in cleaning validation as a complement to traditional techniques.
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Dietary intake and physical activity in severely obese pregnancy in ScotlandMohd Shukri, Nor Azwani January 2012 (has links)
Maternal obesity is associated with adverse effects for mothers and offspring. The primary aim of this thesis was to assess food intake and physical activity (PA) using validated self-administered questionnaires, and whether these were associated with gestational weight gain (GWG) and birthweight (BWT), in severely obese (body mass index, BMI≥40kg/m2) compared with lean pregnant women (BMI 20-25kg/m2). The secondary aims were to validate self-reports against food diary (FD) and accelerometry; to assess the prevalence of under or over-reporting of energy intake; and to carry out a pilot study to assess total energy expenditure, as well as self-reporting accuracy, by using doubly-labelled water (DLW) technique, in subgroups of participants. Pregnant women were recruited from an ongoing study of severe obesity in pregnancy at the Royal Infirmary of Edinburgh, UK. Assessments were done in early (12-20 weeks) and late (28-32 weeks) pregnancy. A subgroup of women also completed questionnaires on appetite, general nutrition knowledge, and eating behaviours. All results were adjusted for age, parity, ethnic origin and deprivation category score. Self-reported total energy intake was not significantly different between obese and lean during early (median 2,444 vs 2,312 kcal/day) and late (2,173 vs 2,354 kcal/day) pregnancy. However when validated with FD, the relative validity of the food frequency questionnaire was lower in obese compared to lean. Under-reporting of total energy intake was higher in obese compared to lean (49% vs 15%, P<0.01) through comparison of selfreported energy intake with estimated total energy expenditure, and this was supported by the DLW pilot study results. The DLW also showed possible over-reporting of PA by the obese group. Obese women reported significantly lower appetite than lean throughout pregnancy (P<0.01). They also had lower scores in general nutrition knowledge, but these were no longer significant after controlling for confounders. Obese women had significantly higher scores of restrained and emotional eating behaviours than, and similar scores of external eating behaviours to, lean. Appetite, nutrition knowledge, restraint and emotional eating behaviours scores were not associated with food intake in either obese or lean. On the other hand, increased intakes of total calories and fats were influenced by increasing score of external eating behaviour in both groups. Obese women reported doing similar amounts of total PA but significantly less of vigorous and sports and exercise activities than lean (P<0.05). Accelerometry showed obese women had lower average activity counts/day, although they did have significantly greater energy expenditure in light-intensity activity than lean (P<0.01). Obese women had less GWG than lean (Mean ± SD, 5.3± 52 vs 10.8±3.7kg, P<0.001). Increased GWG was associated with increased self-reported total energy intake in lean, but this was not seen in obese. GWG was not associated with PA in either group. BWT was not significantly different between obese and lean (3,547±549g vs 3,567±516g). In lean, increased BWT was associated with increased energy intake and total PA. BWT in obese was not associated with diet but with increased with PA in early pregnancy. In conclusion, self-reported methods were less reliable in assessment of diet and PA in severely obese compared to lean pregnant women. These exploratory studies found that obese women did not appear to have the same factors as lean women affecting GWG and BWT, though this may be complicated by the poor reliability of self-reports. Therefore, quantitative assessments such as measurement of serum micronutrient levels (to evaluate nutritional status), and accelerometry (to assess physical activity) may be necessary in this poorly understood population.
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A Validation Study of a Writing Skills Test for Police Recruit ApplicantsStolp, Shelly J. 12 1900 (has links)
This study evaluated the effectiveness of a direct test of higher-order and lower-order writing abilities needed for police report writing. This test was specifically designed to address report writing deficiencies experienced by police in the training academy. Descriptive statistics were examined, and relationships between this test and writing ability dimensions included on a separate, indirect, multiple choice test were investigated. Direct and indirect scores were correlated with training academy performance. Because both tests assessed higher-order and lower-order writing abilities, comparisons were made to determine which type of test was most appropriate for assessing the different types of writing skills. Results indicated that the direct test was a valid predictor of academy performance. Direct methods of measurement were found to be better than indirect methods for assessing higher-order writing skills. For lower-order writing skills, the indirect method appeared to be a better measure than the direct method.
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Job Embeddedness as a Predictor of Voluntary Turnover: Validation of a New InstrumentBesich, John S. 12 1900 (has links)
Voluntary turnover has become a problem for many organizations in today's society. The cost of this turnover reaches beyond organizational impact, but also affects the employees themselves. For this reason, there has been a plethora of research conducted by both academicians and practitioners on the causes and consequences of voluntary turnover. The purpose of this study is to test the validity and generalizability of the job embeddedness model of voluntary turnover to the information technology (IT) industry. The IT field has been plagued with high turnover rates in recent years. In this study, the job embeddedness model (Mitchell et al., 2001) is applied to a population sample consisting of health care information technology employees.
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Validation of diffusive samplers for nitrogen oxides and applications in various environmentsHagenbjörk-Gustafsson, Annika January 2014 (has links)
The overall aim of this thesis was to validate diffusive samplers for measurements of nitrogen dioxide (NO2) and nitrogen oxides (NOx). The Willems badge was validated for NO2 measurements both in laboratory tests and in field tests (Paper I-II). The sampling rate was 40.0 mL/min for ambient air concentrations and 46.0 mL/min for higher concentrations. No effects of different factors on sampling rate were found except for a reduced sampling rate at low wind velocity. The results of the laboratory validation were confirmed in field tests in ambient air and with personal sampling. The correlation between diffusive samplers and the reference monitor was good for ambient measurements. In conclusion, the Willems badge performs well at wind velocities down to 0.3 m/s, and this makes it suitable for personal sampling but less suitable for measurements in indoor air where the wind velocity is lower. Paper III reports about the field validation of the Ogawa diffusive samplers. Absolute humidity and temperature were found to have the strongest effect on sampling rate with lower uptake rates at low absolute humidity or temperature. The sampling rates above 0 °C were 8.6 mL/min for NO2 and 9.9 mL/min for NOx. NO2 and NOx concentrations that were determined using the manufacturer’s protocol were either underestimated or overestimated. The agreement between concentrations measured by the Ogawa sampler and the reference monitor was improved when field-determined sampling rates were used to calculate concentrations. Paper IV is based on a study with the aim of assessing the exposure of the Swedish general population to NO2 and some carcinogenic substances. The surveys were performed in one of five Swedish cities every year. In each survey, personal measurements of NO2 and some carcinogenic substances were conducted on 40 randomly selected individuals. In the study presented in this thesis, the NO2 part of the study is in focus and results were available for eight surveys conducted across the five cities. The estimated arithmetic mean concentration for the general Swedish population was 14.1 μg/m3. The exposure level for NO2 was higher for smokers compared with non-smokers, and the NO2 exposure levels were higher for people who had gas stoves at home or who were exposed at their workplace. The exposure was lower for those who had oil heating in their houses.
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A methodology for validation of high resolution combat modelsCoville, Michael Paul 06 1900 (has links)
Approved for public release; distribution is unlimited / Senior officers in the United States Army have a high degree of confidence that National Training Center simulated combat results are representative, under similar circumstances, of actual combat. A validation methodology for high resolution combat models, primarily based on data acquired from the National Training Center, is the focus of this thesis. The validation methodology, where appropriate, translates confidence in National Training Center realism, to confidence in the combat model. Theoretical issues, existing methodologies, and the impact of model purpose are considered in this research. The final product is a validation methodology that makes use of a realistic representation of combat, automatically updates validation criteria to account for changes in weapons and tactics, and is responsive to the purpose for which the model was designed. / http://archive.org/details/methodologyforva00covi / Captain, United States Army
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