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Bayesian statistical modelling
Vilikus, Ondřej ; Hebák, Petr (advisor) ; Berka, Petr (referee) ; Militký, Jiří (referee)
Conjoint analysis is a popular method in consumer preferences research. One of the factors that caused the increasing popularity of this method in recent years is wide use of hierarchical Bayesian models which has been found invaluable in solving the problem of how to obtain reliable estimates of individual preferences without need for overloading respondents with too many conjoint tasks. First goal of my dissertation was to confirm whether the use of Bayesian models is the best choice under all circumstances or whether there are some limitations of this approach. For this purpose I conducted a study based on simulated datasets. Algorithm used enabled generation of datasets that differed in several parameters of interest but which were most comparable in other aspects. Results show that hierarchical models represent choice leading to highest accuracy in predicting respondents' choices in holdout tasks. Use of hierarchical models is most beneficial in the situation of strongly heterogeneous population yet limited amount of available data. In these cases we are able to capture the structure of heterogeneity with significantly lower number of choice task necessary from each respondent. Second goal of the dissertation was to answer the question whether we can increase also the effectiveness of the questioning in conjoint analysis by adding several direct questions. Suggested hybrid choice-based conjoint method (HCBC) combines conjoint analysis tasks with direct questions regarding the preference of levels for each attribute. These are used during the estimation of the model and for increasing the effectiveness if the conjoint analysis tasks design. The HCBC was compared with traditional choice-based conjoint (CBC) and adaptive choice-based conjoint (ACBC) based on practical study involving 421 respondents randomly assigned in one of three test groups. Suggested method has been found as useful alternative that can help with reducing number of choice task needed and as a solution for some situations when diverse importance of the attributes tested does not allow for indirect estimation of preferences with respect to all attributes tested.
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Personal informatics in practice
Gušiliková, Nina ; Střížová, Vlasta (advisor) ; Toman, Prokop (referee)
The diploma thesis deals with the issue of management system support and human resources development through the use of personal information system in particular company. The main purpose of the thesis is to analyze benefits of human resources information system to increase efficiency, quality of human resource operations accuracy and to decrease human resources operations time consumption. The secondary purpose of the thesis is the knowledge generalisation and the identification of mistakes made by the company during the system implementation. Text of the diploma thesis is divided into two separate sections. First one is theoretically focused and contains three chapters where algorithm of basic activities of human control and new human resources is analysed, which at the end justifies the needs of support of all the personal information system processes. Characteristic of personal information systems and typology of personal information follows. Practical part of thesis deals with critical analysis of implementation of new personal system process in automotive company. The contribution of this thesis includes the summary of know-how gained within human resources system implementation. Conclusions of diploma thesis are based on results of basic pair methods of scientific work. Data for critical analysis were gained by analysis of project documentation, content analysis of company documents, interviews with company managers and form research between managers and company employees.
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Zeemanův jev v polovodičových kvantových strukturách
Stráský, Josef ; Grill, Roman (advisor) ; Výborný, Karel (referee)
This theoretical thesis presents detailed study of negatively charged excitons - trions - confined in single quantum well in presence of perpendicular magnetic field. Complex valence band of GaAs/GaAlAs compound is described within Luttinger Hamiltonian framework. Singlet and triplet states of negative trion are introduced. Advanced theoretical analysis of Zeeman effect for different states of trion is performed. Landau gauge of magnetic field and unusual wavefunctions basis is chosen and its accuracy is tested. Evolution of ground state energy and photoluminescence spectra with magnetic field is evaluated for different values of Landé g-factors. Probability of occurrence of electrons with respect to the hole position and their spatial correlation function are investigated.
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Evaluation of influence of interpolation methods on coregistration of radar images
Slačíková, Jana ; Potůčková, Markéta (advisor) ; Hlaváčová, Ivana (referee)
Evaluation of influence of interpolation methods on coregistration of radar images Abstract SAR interferogram processing requires subpixel coregistration of SAR image pair for accurate phase differencing. Errors in alignment introduce phase noise in SAR interferogram. Last step in coregistration is resampling one of SAR images. Also this step introduces errors in SAR interferogram. The resampling algorithms Nearest Neighbor, Bilinear interpolation, Cubic Convolution and advanced methods such as Raised Cosine kernel, Knab interpolation kernel and Truncated Sinc were tested on ERS tandem data and compared. The results were compared with the theory and simulations of earlier investigations (Hanssen, Bamler, 1999), (Migliaccio, Bruno, 2003) and (Cho ... [et al.], 2005). The main experiment in this work was to examine and compare resampling methods on real data to evaluate their effect on the interferometric phase quality and DEM generation. The coregistration performance was evaluated by the coherence (Touzi ... [et al.], 1999) and the sum of phase differences (Li ... [et al.], 2004). No evidence showed that computationally intensive algorithms produced better quality of interferogram than Cubic Convolution. The possibilities of evaluating by means of the accuracy of the final InSAR DEM (Li, Bethel, 2008) were...
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Language recognition performed on a short text sample
Zahornadský, Ján ; Raab, Jan (referee) ; Bejček, Eduard (advisor)
This paper extends the work of Cavnar and Trenkle N-gram text categorization [2], enhances the study of statistics application on document language recognition as simplier variant of categorization. Proposed program shows qualities like modular design or running on one universal character set. As an enhancement of the original work is presented an automatic text sample filtration algorithm altogether with Internet text extraction and iterative improvement for this purpose. Presented paper studies accuracy development, concentrating on short samples. Similar work was not found in available literature, as categorization (and in corollary language recognition) usually assumes long enough input. In conclusion, a discussion about using the learned data and algorithms created here to mark foreign phrases. To be specific, we study the application on Prague Dependency Treebank [8], where the foreign phrases are not recognized, only their occurences specified.
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Tuned semiconductor laser for the diagnostic of the channel waveguides
Ondráček, František ; Skalský, Miroslav ; Čtyroký, Jiří
In contribution is described new measuring set up with tuned semiconductor laser and there are given first results of spectral losses and group refractive index in various channel waveguides by using a resonator method. The waveguides were prepared in special glasses by ion exchanges method and in LiNbO.sub.3./sub. crystal by proton exchange and also by titan difusion. Experimental results have demonstrated accuracy and rate of this arangement. In conclusion we have shown the possibility of the next research.
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Analytical determination of active compounds by liquid chromatography.
Janurová, Catherine ; Sochor, Jaroslav (advisor) ; Kastner, Petr (referee)
Analytical determination of active compounds by liquid chromatography Diploma Thesis Catherine Janurová Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Chemistry and Drug Control, Heyrovského 1203, Hradec Králové This paper deals with the HPLC evaluation of dexamethasone in ointment base. Dexamethasone was analysed by the use of a C-18 column, a water: acetonitrile (40:60) mobile phase, flow rate of 0,6 ml/min and a UV detector set at 239 nm. An internal standard was used for quantitative determination. Acetonitrile was shown to be the best solvent for the isolation of dexamethasone from the ointment base. A calibration curve was constructed and verified, by means of which the concentration of dexamethasone in ointment was determined. The elaborated method was validated. Validation parameters: precision, accuracy, selectiveness, linearity, detection limit, quantitative limit and robustness were evaluated.
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Determination of adrenaline and noradrenaline in plasma by HPLC
Kučerová, Tereza ; Klapková, Eva (advisor) ; Kotaška, Karel (referee)
The target of this bacalary work was to validate the metod for determination of adrenaline and noradrenaline in plasma by high performance liquid chromatography with electrochemical (coulometric) detection. The metod was first necessary to optimize for the coulometric detection because it was used the Bio-Rad kit, which was designed to determine with amperometric detection. The principle of this metod is the chromatographic separation of substances with subsequent oxidation of the determined analyte passes through the analytic cell with coulometric detection. The part of the analytical procedure is the solid phase extraction. The part of this work was the optimization of the metod for the coulometric detector. For the analysis were selected following potentials: channel 1 - 350 mV with range 100 nA, channel 2 - 0 mV with range 50 nA, guard channel 0 mV with range 50 nA. Furthermore, the chromatographic metod was fully validated (accuracy, precision, limit of detection, robustness). In the conclusion was made interlaboratory comparison of results of 42 patients samples with those obtained in the hospital Šternberk.
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Employment of separation methods in the field of drug analysis II.
Ferebauerová, Markéta ; Kastner, Petr (referee) ; Kučera, Radim (advisor)
Employment of separation methods in the field of drug analysis II Diploma Thesis Markéta Ferebauerová Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Drug Control This diploma thesis summarizes findings of both drug analysis done by gas chromatography and validation of analytical method. The mixture of glycerol, 1,3-butanediol and two other substances was studied. Specifity, linearity, precision and accuracy were studied and verified. In terms of robustness, the following parameters of the method were changed: the flow rate of carier gas, spit ratio, carier gas, stability of the sample, the temperature of detector, the temperature of injection port and the temperature of column. Further, the author demonstrate that the method is mostly influenced by the flow rate of carier gas and the temperature of column of the first part. Finally,the 24-hour stability of the sample was confirmed.
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