• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1225
  • 305
  • 123
  • 100
  • 67
  • 60
  • 42
  • 24
  • 22
  • 18
  • 14
  • 13
  • 8
  • 7
  • 7
  • Tagged with
  • 2420
  • 878
  • 404
  • 335
  • 301
  • 245
  • 238
  • 204
  • 196
  • 190
  • 178
  • 170
  • 166
  • 152
  • 148
  • 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.
51

INTELLIGENT SYSTEM FOR MONITORING PHYSIOLOGICAL PARAMETERS USING CAMERA

Karim, Kh Nafis January 2015 (has links)
Measuring physiological parameters or vital sign using camera has become popular in recent years. Contact-less monitoring and extraction of vital signs can be important source of information in situations like medical care system and safety control system. This paper presents the implementation of real-time, non-contact method for extraction of vital signs, heart rate in this case. A better face tracking method is used for efficient face detection. This study extends some of the previous works done and have a comparison study with several methods. The developed system used filtering with window over the green channel of the signal and then Converted to frequency domain to analyze the signal to detect heart rate. The developed system achieved high correlation and showed small error while referencing with actual heart signal from ECG. This method delivers better result in better light condition but gives fairly good result on lower light as well.
52

A moving boundary problem in a distributed parameter system with application to diode modeling

Zhang, Hanzhong 14 April 2011 (has links)
Not available / text
53

Parameter estimation in small extensive air showers

周志堅, Chow, Chi-kin. January 1993 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
54

Parameter estimation in ordinary differential equations

Ng, Chee Loong 30 September 2004 (has links)
The parameter estimation problem or the inverse problem of ordinary differential equations is prevalent in many process models in chemistry, molecular biology, control system design and many other engineering applications. It concerns the re-construction of auxillary parameters by fitting the solution from the system of ordinary differential equations( from a known mathematical model) to that of measured data obtained from observing the solution trajectory. Some of the traditional techniques (for example, initial value technques, multiple shooting, etc.) used to solve this class of problem have been discussed. A new algorithm, motivated by algorithms proposed by Childs and Osborne(1996) and Z.F.Li's dissertation(2000), has been proposed. The new algorithm inherited the advantages exhibited in the above-mentioned algorithms and, most importantly, the parameters can be transformed to a form that are convenient and suitable for computation. A statistical analysis has also been developed and applied to examples. The statistical analysis yields indications of the tolerance of the estimates and consistency of the observations used.
55

Self adaptation in evolutionary algorithms

Smith, James Edward January 1998 (has links)
Evolutionary Algorithms are search algorithms based on the Darwinian metaphor of “Natural Selection”. Typically these algorithms maintain a population of individual solutions, each of which has a fitness attached to it, which in some way reflects the quality of the solution. The search proceeds via the iterative generation, evaluation and possible incorporation of new individuals based on the current population, using a number of parameterised genetic operators. In this thesis the phenomenon of Self Adaptation of the genetic operators is investigated. A new framework for classifying adaptive algorithms is proposed, based on the scope of the adaptation, and on the nature of the transition function guiding the search through the space of possible configurations of the algorithm. Mechanisms are investigated for achieving the self adaptation of recombination and mutation operators within a genetic algorithm, and means of combining them are investigated. These are shown to produce significantly better results than any of the combinations of fixed operators tested, across a range of problem types. These new operators reduce the need for the designer of an algorithm to select appropriate choices of operators and parameters, thus aiding the implementation of genetic algorithms. The nature of the evolving search strategies are investigated and explained in terms of the known properties of the landscapes used, and it is suggested how observations of evolving strategies on unknown landscapes may be used to categorise them, and guide further changes in other facets of the genetic algorithm. This work provides a contribution towards the study of adaptation in Evolutionary Algorithms, and towards the design of robust search algorithms for “real world” problems.
56

A parameter optimisation tool for excitable cell mathematical models based on CellML

Hui, Ben Bunny Chun Bun, Graduate School of Biomedical Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Mathematical models are often used to describe and, in some cases predict, excitable cellular behaviour that is based on observed experimental results. With the increase of computational power, it is now possible to solve such models in a relatively short time. This, along with an increasing knowledge of cellular and subcellular processes, has led to the development of a large number of complex cellular models, capable of describing a broad range of excitable cell behaviour. But the use of complex models can also lead to problems. Most models can accurately reproduce results associated with the data on which the models are based. However, results from complicated models, with large numbers of variables and parameters, are less reliable if the model is not placed under the same physiological conditions as defined by the model author. In order to test a model??s suitability and robustness over a range of physiological conditions, one needs to fit model parameters against experimental data observed under those conditions. By using the modelling standard and repository offered by CellML, model users can easily select and adapt a large number of models to set up their own applications to fit model parameters against user-supplied experimental data. However, currently there is a lack of software that can utilise CellML model for parameter fitting. In this thesis, a Java-based utility has been developed, capable of performing least square parameter optimisation for a wide range of CellML models. Using the developed software, a number of parameter fits and identifiability analyses were performed on a selected group of CellML models. It was found that most of the models were ill-formed, with larger numbers of parameters worsening model identifiability. In some cases, the usage of multiple datasets and different objective functions can improve model identifiability. Finally, the developed software was used to perform parameter optimisation against two sets of action potentials from a sinoatrial node experiment, in the absence and presence of E9031, a specific ion channel blocker.
57

A parameter optimisation tool for excitable cell mathematical models based on CellML

Hui, Ben Bunny Chun Bun, Graduate School of Biomedical Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Mathematical models are often used to describe and, in some cases predict, excitable cellular behaviour that is based on observed experimental results. With the increase of computational power, it is now possible to solve such models in a relatively short time. This, along with an increasing knowledge of cellular and subcellular processes, has led to the development of a large number of complex cellular models, capable of describing a broad range of excitable cell behaviour. But the use of complex models can also lead to problems. Most models can accurately reproduce results associated with the data on which the models are based. However, results from complicated models, with large numbers of variables and parameters, are less reliable if the model is not placed under the same physiological conditions as defined by the model author. In order to test a model??s suitability and robustness over a range of physiological conditions, one needs to fit model parameters against experimental data observed under those conditions. By using the modelling standard and repository offered by CellML, model users can easily select and adapt a large number of models to set up their own applications to fit model parameters against user-supplied experimental data. However, currently there is a lack of software that can utilise CellML model for parameter fitting. In this thesis, a Java-based utility has been developed, capable of performing least square parameter optimisation for a wide range of CellML models. Using the developed software, a number of parameter fits and identifiability analyses were performed on a selected group of CellML models. It was found that most of the models were ill-formed, with larger numbers of parameters worsening model identifiability. In some cases, the usage of multiple datasets and different objective functions can improve model identifiability. Finally, the developed software was used to perform parameter optimisation against two sets of action potentials from a sinoatrial node experiment, in the absence and presence of E9031, a specific ion channel blocker.
58

Orthogonal statistics and some sampling properties of moment estimators for the negative binomial distribution /

Myers, Raymond Harold, January 1963 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute, 1963. / Vita. Abstract. Includes bibliographical references (leaves 124-126). Also available via the Internet.
59

Modeling and parameter estimation of cardiopulmonary dynamics /

Choi, Younhee. January 2005 (has links)
Thesis (Ph.D.)--University of Rhode Island, 2005. / Includes bibliographical references (leaves 90-95).
60

A framework for distributed applications on systems with mobile hosts

Skawratananond, Chakarat. January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Page generated in 0.1011 seconds