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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A benchmarking study on information management systems for water laboratories in South Africa

Broodryk, GJ, de Beer, WHJ 01 January 2003 (has links)
The increasing demand for the chemical monitoring of water qualities emphasises the importance of an efficient and workable laboratory management system to remain profitable and competitive in a fast growing industry. The management of information is therefore becoming increasingly important as the effectiveness and profitability of the water laboratory is largely measured against its management systems and continual improvement programmes. Effective information management forms an important part of laboratory management to ensure that data are updated and remain current. One way of proving its effectiveness, the laboratory must provide proof of a controlled and procedurised documentation system and the availability of updated data and information. The effective control of data and information in the water laboratory by using some kind of information management system is therefore essential. Laboratory managers are becoming aware of the need for an effective, computerised laboratory data and information management system as the entry of data and results into a manual system has several disadvantages. The laboratory manager is increasingly seeking for ways to improve the efficiency of his laboratory and more time must therefore be spent on managing the laboratory, rather than to facilitate the distribution and control of information.
2

Statistical properties of successive ocean wave parameters

Wist, Hanne Therese January 2003 (has links)
<p>For random waves the free surface elevation can be described by a number of individual wave parameters. The main objective of this work has been to study the statistical properties of individual parameters in successive waves; the wave crest height, the wave height and the wave period.</p><p>In severe sea states the wave crest heights exhibit a nonlinear behavior, which must be reflected in the models. An existing marginal distribution that uses second order Stokes-type nonlinearity is transformed to a two-dimensional distribution by use of the two–dimensional Rayleigh distribution. This model only includes sum frequency effects. A two-dimensional distribution is also established by transforming a second order model including both sum and different frequency effects. Both models are based on the narrow-band assumption, and the effect of finite water depth is included. A parametric wave crest height distribution proposed by Forristall (2000) has been extended to two dimensions by transformation of the two-dimensional Weibull distribution. </p><p>Two successive wave heights are modeled by a Gaussian copula, which is referred to as the Nataf model. Results with two initial distributions for the transformation are presented, the Næss (1985) model and a two-parameter Weibull distribution, where the latter is in best agreement with data. The results are compared with existing models. The Nataf model has also been used for modeling three successive wave heights. Results show that the Nataf transformation of three successive wave heights can be approximated by a first order autoregression model. This means that the distribution of the wave height given the previous wave height is independent of the wave heights prior to the previous wave height. The simulation of successive wave heights can be done directly without simulating the time series of the complete surface elevation. </p><p>Successive wave periods are modeled with the Nataf transformation by using a two-parameter Weibull distribution and a generalized Gamma distribution as the initial distribution, where the latter is in best agreement with data. Results for the marginal and two-dimensional distributions are compared with existing models. In practical applications, it is often of interest to consider successive wave periods with corresponding wave heights exceeding a certain threshold. Results show that the distribution for successive wave periods when the corresponding wave heights exceed the root-mean-square value of the wave heights can be approximated by a multivariate Gaussian distribution. When comparing the results with data, a long time series is needed in order to obtain enough data cases. Results for three successive wave periods are also presented. </p><p>The models are compared with field data from the Draupner field and the Japan Sea, and with laboratory data from experiments at HR Wallingford. In addition, data from numerical simulations based on second order wave theory, including both sum and frequency effects, are included.</p>
3

Statistical properties of successive ocean wave parameters

Wist, Hanne Therese January 2003 (has links)
For random waves the free surface elevation can be described by a number of individual wave parameters. The main objective of this work has been to study the statistical properties of individual parameters in successive waves; the wave crest height, the wave height and the wave period. In severe sea states the wave crest heights exhibit a nonlinear behavior, which must be reflected in the models. An existing marginal distribution that uses second order Stokes-type nonlinearity is transformed to a two-dimensional distribution by use of the two–dimensional Rayleigh distribution. This model only includes sum frequency effects. A two-dimensional distribution is also established by transforming a second order model including both sum and different frequency effects. Both models are based on the narrow-band assumption, and the effect of finite water depth is included. A parametric wave crest height distribution proposed by Forristall (2000) has been extended to two dimensions by transformation of the two-dimensional Weibull distribution. Two successive wave heights are modeled by a Gaussian copula, which is referred to as the Nataf model. Results with two initial distributions for the transformation are presented, the Næss (1985) model and a two-parameter Weibull distribution, where the latter is in best agreement with data. The results are compared with existing models. The Nataf model has also been used for modeling three successive wave heights. Results show that the Nataf transformation of three successive wave heights can be approximated by a first order autoregression model. This means that the distribution of the wave height given the previous wave height is independent of the wave heights prior to the previous wave height. The simulation of successive wave heights can be done directly without simulating the time series of the complete surface elevation. Successive wave periods are modeled with the Nataf transformation by using a two-parameter Weibull distribution and a generalized Gamma distribution as the initial distribution, where the latter is in best agreement with data. Results for the marginal and two-dimensional distributions are compared with existing models. In practical applications, it is often of interest to consider successive wave periods with corresponding wave heights exceeding a certain threshold. Results show that the distribution for successive wave periods when the corresponding wave heights exceed the root-mean-square value of the wave heights can be approximated by a multivariate Gaussian distribution. When comparing the results with data, a long time series is needed in order to obtain enough data cases. Results for three successive wave periods are also presented. The models are compared with field data from the Draupner field and the Japan Sea, and with laboratory data from experiments at HR Wallingford. In addition, data from numerical simulations based on second order wave theory, including both sum and frequency effects, are included.
4

Use of the SOAP analysis package at BSU with respect to experiment E781 at Fermi National Laboratory

Alkhalifah, Ahmed A. January 2000 (has links)
This project was done in the context of FNAL Experiment E781 (the charm baryon study), which took data during the 1996-97 "fixed-target" run, using the SELEX detector, and a 650-GeV sigma hyperon beam derived from a production target exposed to the 1-TeV ultra-high energy proton beam out of the FNAL TEVATRON accelerator.We used the SSH encrypted TELNET to penetrate the BSU firewall to gain access to the FNAL E781 computer system.We did SELEX VDC alignments of runs 5577, and 7413, via telnet to the E781 computer system, using E78 I's SOAP analysis package then broadcasted the results to E781 collaborators.Also, we installed REDHAT-6.2's distribution of the LINUX OS, and then studied, downloaded and investigated (installing/compiling/testing) the E781 SOAP analysis package on several local BSU PC's. We analyzed and displayed these local tests results with the PAW graphics software (itself downloaded from the CERN laboratory). / Department of Physics and Astronomy

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