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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.
21

Cooperative UAV Search and Intercept

Sun, Andrew 22 September 2009 (has links)
In this thesis, a solution to the multi-Unmanned Aerial Vehicle (UAV) search and intercept problem for a moving target is presented. For the search phase, an adapted diffusion-based algorithm is used to manage the target uncertainty while individual UAVs are controlled with a hybrid receding horizon / potential method. The coordinated search is made possible by an uncertainty weighting process. The team intercept phase algorithm is a behavioural approach based on the analytical solution of Isaac's Single-Pursuer/Single-Evader (SPSE) homicidal chau ffeur problem. In this formulation, the intercepting control is taken to be a linear combination of the individual SPSE controls that would exist for each of the evader/pursuer pairs. A particle swarm optimizer is applied to find approximate optimal weighting coefficients for discretized intervals of the game time. Simulations for the team search, team intercept and combined search and intercept problem are presented.
22

Cooperative UAV Search and Intercept

Sun, Andrew 22 September 2009 (has links)
In this thesis, a solution to the multi-Unmanned Aerial Vehicle (UAV) search and intercept problem for a moving target is presented. For the search phase, an adapted diffusion-based algorithm is used to manage the target uncertainty while individual UAVs are controlled with a hybrid receding horizon / potential method. The coordinated search is made possible by an uncertainty weighting process. The team intercept phase algorithm is a behavioural approach based on the analytical solution of Isaac's Single-Pursuer/Single-Evader (SPSE) homicidal chau ffeur problem. In this formulation, the intercepting control is taken to be a linear combination of the individual SPSE controls that would exist for each of the evader/pursuer pairs. A particle swarm optimizer is applied to find approximate optimal weighting coefficients for discretized intervals of the game time. Simulations for the team search, team intercept and combined search and intercept problem are presented.
23

Exploiting temporal redundancy for the detection and estimation of low probability of intercept radar /

Oke, C. Wesley. January 1900 (has links)
Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 83-86). Also available in electronic format on the Internet.
24

Bayesian D-Optimal Design Issues and Optimal Design Construction Methods for Generalized Linear Models with Random Blocks

January 2015 (has links)
abstract: Optimal experimental design for generalized linear models is often done using a pseudo-Bayesian approach that integrates the design criterion across a prior distribution on the parameter values. This approach ignores the lack of utility of certain models contained in the prior, and a case is demonstrated where the heavy focus on such hopeless models results in a design with poor performance and with wild swings in coverage probabilities for Wald-type confidence intervals. Design construction using a utility-based approach is shown to result in much more stable coverage probabilities in the area of greatest concern. The pseudo-Bayesian approach can be applied to the problem of optimal design construction under dependent observations. Often, correlation between observations exists due to restrictions on randomization. Several techniques for optimal design construction are proposed in the case of the conditional response distribution being a natural exponential family member but with a normally distributed block effect . The reviewed pseudo-Bayesian approach is compared to an approach based on substituting the marginal likelihood with the joint likelihood and an approach based on projections of the score function (often called quasi-likelihood). These approaches are compared for several models with normal, Poisson, and binomial conditional response distributions via the true determinant of the expected Fisher information matrix where the dispersion of the random blocks is considered a nuisance parameter. A case study using the developed methods is performed. The joint and quasi-likelihood methods are then extended to address the case when the magnitude of random block dispersion is of concern. Again, a simulation study over several models is performed, followed by a case study when the conditional response distribution is a Poisson distribution. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2015
25

Detekce nestabilit v některých panelových datech / Detection of instabilities in some panel data

Láf, Adam January 2018 (has links)
This thesis deals with the detection of change in the intercept in panel data re- gression model. We are interested in testing a null hypothesis that there was no change in the intercept during the observation period in case with no depen- dency between panels and with the number of panels and observations in each panel going to infinity. Based on the results for simplified case with no additional regressors we propose a statistical test and show its properties. We also derive a consistent estimate of the parameter of change based on the least squares me- thod. The main contribution of the thesis is the derivation of theoretical results of the proposed test while variances of errors are known and its modification for unknown variance parameters. A large simulation study is conducted to examine the results. Then we present an application to real data, particularly we use four factor CAPM model to detect change in monthly returns of US mutual funds during an observation period 2004-2011 and show a significant change during the sub-prime crisis in 2007-2008. This work expands existing results for de- tecting changes in the mean in panel data and offers many directions for further beneficial research. 1
26

QUALITY OF TACSI PLATELETS AND THEIR EFFECT ON THROMBOCYTOPENIA PATIENTS

Lundin, Ann-Sofie January 2010 (has links)
Conclusion:Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.     Methods: A new approach that pools 8 buffy coats (TACSI platelets) that were separated into 2 units instead of 4-6 buffy coats pooled to 1 unit was investigated in this study. After the platelets were extracted from the buffy coats their quality was controlled and subsequently the platelet product was evaluated in 96 patients.   Results: The results showed that 80 % of the platelet units passed the European quality requirements. Further, the platelet count was increased in most patients that received TACSI platelets. Conclusion: Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.
27

Analysis of energy based signal detection

Lehtomäki, J. (Janne) 29 November 2005 (has links)
Abstract The focus of this thesis is on the binary signal detection problem, i.e., if a signal or signals are present or not. Depending on the application, the signal to be detected can be either unknown or known. The detection is based on some function of the received samples which is compared to a threshold. If the threshold is exceeded, it is decided that signal(s) is (are) present. Energy detectors (radiometers) are often used due to their simplicity and good performance. The main goal here is to develop and analyze energy based detectors as well as power-law based detectors. Different possibilities for setting the detection threshold for a quantized total power radiometer are analyzed. The main emphasis is on methods that use reference samples. In particular, the cell-averaging (CA) constant false alarm rate (CFAR) threshold setting method is analyzed. Numerical examples show that the CA strategy offers the desired false alarm probability, whereas a more conventional strategy gives too high values, especially with a small number of reference samples. New performance analysis of a frequency sweeping channelized radiometer is presented. The total power radiometer outputs from different frequencies are combined using logical-OR, sum and maximum operations. An efficient method is presented for accurately calculating the likelihood ratio used in the optimal detection. Also the effects of fading are analyzed. Numerical results show that although sweeping increases probability of intercept (POI), the final probability of detection is not increased if the number of observed hops is large. The performance of a channelized radiometer is studied when different CFAR strategies are used to set the detection threshold. The proposed iterative methods for setting the detection threshold are the forward consecutive mean excision (FCME) method with the CA scaling factors in final detection decision (FCME+CA), the backward consecutive mean excision (BCME) method with the CA scaling factors in detection (BCME+CA) and a method that uses the CA scaling factors for both censoring and detection (CA+CA). Numerical results show that iterative CFAR methods may improve detection performance compared to baseline methods. Finally, a method to set the threshold of a power-law detector that uses a nonorthogonal transform is presented. The mean, variance and skewness of the decision variable in the noise-only case are derived and these are used to find a shifted log-normal approximation for the distribution of the decision variable. The accuracy of this method is verified through simulations.
28

Rychlé rozpoznání aplikačního protokolu / Fast Recognition of Application Protocol

Adámek, Michal January 2012 (has links)
This thesis focuses on methods for fast recognition of application protocols. Fast recognition is recognition with minimal delay from the time of capturing the first data packet sent  from the source node. This thesis describes possible techniques and methods for recognition of application protocols and basic information and description of reference system for lawful interception in computer networks. Furthermore, the thesis describes analysis, design and implementation phase of a tool for fast recognition of application protocols. The conclusion of this thesis describes the results of tests performed by the tool and shows its limitations and possible extensions.
29

The Time Slot Interchange in a Digital Central Office

Al-Maalouf, Khalil George 01 January 1988 (has links) (PDF)
The invention of the telephone and the telegraph opened the door to worldwide corrmunications. Over the years, complex and versatile corrmunication systems have evolved involving many devices and technologies. Switching protocols between switching offices have been established in accordance with the nature of the machines and with the capabilities of the transmission medium and its environment. Switching systems are now stored program oriented, providing a more generalized and digitally oriented internal switching capability. This report will discuss the Time Slot Interchange ( TSI), an important component of the Digital Central Office (DCO). The operation of the send section and the receive section and their relationship to the port group highways and cross office highways are presented in detail. The various TSI corrmands for performing the necessary operations are discussed. The TSI considered is that designed by Stromberg-Carlson, and future design trends in the design are presented.
30

Semiklasická energie eliptické Nambuovy-Gotovy struny / Semi-classical energy of elliptic Nambu-Goto string

Kozoň, Marek January 2018 (has links)
Po zhrnutí potrebných teoretických základov a predošlého výskumu v ob- lasti, prezentujeme semi-klasickú kvantovaciu schému pre uzavretú Nambuovu- Gotovu strunu. Týmto zovšeobecňujeme predošlú prácu, ktorá bola vykonaná pre otvorenú strunu a uzavretú strunu kruhového tvaru. Pomocou metód kvan- tovej teórie po©a v zakrivených priestoročasoch počítame strednú hodnotu vo©- ného Hamiltoniánu struny rotujúcej v dvoch na seba kolmých priestorových rovinách v priestoročase všeobecnej dimenzie. Táto hodnota je priamo úmerná kvantovej korekcii k celkovej energii struny, ktorá má formu tzv. Reggeovho interceptu. Výslednú hodnotu Reggeovho interceptu porovnávame s predošlým výskumom. Taktiež uvádzame porovnanie získaného spektra fyzikálnych stavov struny kvantovanej našou metódou so spektrom odvodeným pomocou kovariant- ného kvantovania. 1

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