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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

A model ISM-MICMAC for managing risk in agri-food supply chain: An investigation from the Andean region of Peru

Ramos, Edgar, Pettit, Timothy J., Habib, Mamun, Chavez, Melissa 01 January 2021 (has links)
During recent years, supply chain risks have gained importance in the food supply chain. This study presents a methodology to analyse the risk in the agri-food supply chain belonging to the Andean region in Peru. It utilises the interpretive structural modelling (ISM) with matrice d' impacts croises multiplication appliqué an classement (cross-impact matrix multiplication applied to classification, abbreviated as MICMAC) to identify and understand relationships between risk types. Based on the empirical data collected from the food industry experts, ten risk factors were identified as relevant. Finally, the identified risks were classified using ISM-MICMAC methodology. The research findings demonstrated that natural disaster, environmental, and legal risks were the most substantial. The findings highlight that selected methods are capable of recognising the most substantial risks that are most critical to assess, manage with adequate mitigation actions from the practitioners in the agri-food industry.
22

Mezinárodní srovnatelnost postojových škál sociálního kapitálu a politického odcizení v Evropském sociálním výzkumu / Cross-Country Comparability of Social Capital and Political Disaffection Attitude Scales in the European Social Survey

Anýžová, Petra January 2014 (has links)
Petra A n ý ž o v á Doctoral thesis: Cross-Country Comparability of Social Capital and Political Disaffection Attitude Scales in the European Social Survey Abstract The doctoral thesis deals with the methodological perspectives of comparative cross-national research. Currently, in the globalization period, the importance of these perspectives has been increasing. Unfortunately, social scientists analyse attractive international data more and more often without realising the levels of data comparability. Therefore they are not fully aware the best approach to statistical analysis of these data and their convenient comparative interpretation. This thesis introduces the issue of data equivalence as one of the most important quality aspects of cross-national research and focuses especially on attitude scales owing to the fact that their comparability is endangered the most in comparative research. In particular, the subject of the analysis is the international comparability of two of the most frequent robust attitude scales: namely social capital and political disaffection scales as they are measured in the European Social Survey first data set. In sociology and political science, these two social science concepts are very significant and they have been studied both theoretically and empirically as social...
23

Stochastic Modelling of Flexible Pavement Performance

Dilip, Deepthi Mary January 2015 (has links) (PDF)
Stochastic analysis provides a rationale for the treatment of uncertainties, founded on the principles of probability theory and statistics, and is concerned with a quantifiable measure of the confidence or the reliability associated with any design process. In this thesis, a stochastic approach is employed in the design of flexible pavement structures, to facilitate the development of safe and reliable pavement structures. The important aspects that have been explored in sufficient detail include the system reliability and global sensitivity analysis, and the spatial and temporal uncertainties that pervade the life of pavements. Chapter 1 of the thesis provides an introduction to the stochastic modelling of flexible pavements and its significance in the present day. Highlighting the need for this study, this chapter also enumerates its objectives and presents an overview of the organization of the thesis. Chapter 2 provides a review of the existing literature of the design of flexible pavements and the approaches adopted to deal with the various sources of uncertainties in a probabilistic setting. The estimation of the uncertainties in fundamental pavement design inputs and their integration into the general performance prediction procedures has become a required component of the modern Mechanistic-Empirical pavement design methodology, which has been described in detail. This chapter also provides the scope of the thesis by identifying the areas of stochastic analysis that have received little attention in the flexible pavement design, which include the effect of spatial variability on the pavement structural responses and the techniques of global sensitivity analysis. Chapter 3 provides a detailed overview of the various methodologies adopted in this thesis to carry out the stochastic modelling of flexible pavements. The fundamental technique adopted for the analysis of reliability is the Monte Carlo Simulation (MCS), which relies upon a numerical/analytical model of the physical system, i.e. the pavement model and a probabilistic description of the design parameters represented by random variables or random fields. The high computational expense associated with the MCS, particularly in the case of random fields, is tackled by the use of meta-models based on the stochastic response surface methodology. The chapter outlines the steps followed to develop the meta-models in the form of Polynomial Chaos Equations (PCEs) and its extension to the Sparse PCE that can conveniently represent the spatial variability of the pavement fields. Chapter 4 deals with the probabilistic modelling of flexible pavements, where the design parameter and model uncertainties are quantified based on the available literature studies. The global sensitivity analysis, which aims to study the impact of the input uncertainty on the variation of a model output (critical pavement responses) through uncertainty propagation, is achieved by the construction of the Polynomial Chaos Equations (PCEs). To implement the global sensitivity analysis in a system reliability framework, a generalized approach based on Bayes’ theorem and the concept of entropy as a sensitivity measure, has been proposed in this chapter. Chapter 5 deals with the characterization of the spatial variability inherent in the pavement layer by employing random fields and analyzing the effect on the pavement responses. The discretization of the random field into a vector of random variables is achieved through the simple Midpoint Discretization and the efficient Expansion Optimal Linear Estimation method. Since the computational effort in stochastic problems is proportional to the number of random variables involved, it is desirable to use a small number of random variables to represent the random field. To achieve this, the principle of transformation of the original random variables into a set of uncorrelated random variables through an eigenvalue orthogonalization procedure is adopted. To further increase the computational efficiency of generating random fields for Monte Carlo Simulation, the variance reduction technique of Latin Hypercube Sampling and the meta-modelling technique using Sparse Polynomial Chaos Equations (SPCEs) are implemented. The primary focus of this chapter is to analyze the influence of the spatial variability of the pavement layer moduli, including its anisotropic characteristics on the pavement structural responses. Chapter 6 focuses on the time-dependent reliability of the pavement structures as they age in service, with due consideration given to degradation of strength with traffic loading. The study is concerned with the fatigue reliability and thereby only the decrease in the asphalt modulus with time is considered as a function of the accumulated damage due to repeated loading, whose uncertainty is determined by the uncertainties of material parameters and the traffic loading. The time-dependent model adopted in this chapter can be quite effortlessly embedded in the Mechanistic-Empirical design framework, and provides a tool to effectively schedule the maintenance of the pavement structure and ensure that the reliability level remains at the desired level for the entire design life of the structure. Chapter 7 summarizes the various studies reported in this thesis and highlights the important conclusions.
24

Identification and validation of putative therapeutic and diagnostic antimicrobial peptides against HIV: An in silico approach

January 2013 (has links)
Magister Scientiae (Medical Bioscience) - MSc(MBS) / Background: Despite the effort of scientific research on HIV therapies and to reduce the rate of HIV infection, AIDS remains one of the major causes of death in the world and mostly in sub-Saharan Africa. To date, neither a cure nor an HIV vaccine had been found and the disease can only be managed by using High Active Antiretroviral Therapy (HAART) if detected early. The need for an effective early diagnostic and non-toxic treatment has brought about the necessity for the discovery of additional HIV diagnostic methods and treatment regimens to lower mortality rates. Antimicrobial Peptides (AMPs) are components of the first line of defense of prokaryotes and eukaryotes and have been proven to be promising therapeutic agents against HIV. Methods: With the utility of computational biology, this work proposes the use of profile search methods combined with structural modeling to identify putative AMPs with diagnostic and anti-HIV activity. Firstly, experimentally validated anti-HIV AMPs were retrieved from various publicly available AMP databases, APD, CAMP, Bactibase and UniProtKB and classified according to super-families. Hidden Markov Model (HMMER) and Gap Local Alignment of Motifs (GLAM2) profiles were built for each super-family of anti- HIV AMPs. Putative anti-HIV AMPs were identified after scanning genome sequence databases using the trained models, retrieved AMPs, and ranked based on their E-values. The 3-D structures of the 10 peptides that were ranked highest were predicted using 1-TASSER. These peptides were docked against various HIV proteins using PatchDock and putative AMPs showing the highest affinity and having the correct orientation to the HIV -1 proteins gp120 and p24 were selected for future work to establish their function in HIV therapy and diagnosis. Results: The results of the in silica analysis showed that the constructed models using the HMMER algorithm had better performances compare to that of the models built by the GLAM2 algorithm. Furthermore, the former tool has a better statistical and probability explanation compared to the latter tool. Thus only the HMMER scanning results were considered for further study. Out of 1059 species scanned by the HMMER models, 30 putative anti-HIV AMPs were identified from genome scans with the family-specific profile models after the elimination of duplicate peptides. Docking analysis of putative AMPs against HIV proteins showed that from the 10 best performing anti-HIV AMPs with the highest E-scores, molecules 1,3, 8, and 10 firmly bind the gp120 binding pocket at the VIN2 domain and the point of interaction between gp120 and T cells, with the 1st and 3rd highest scoring anti-HIV AMPs having the highest binding affinities. However, all 10 putative anti-HIV AMPs bind to the N-terminal domain of p24 with large surface interaction, rather than the C-terminal. Conclusion: The in silica approach has made it possible to construct computational models having high performances, and which enabled the identification of putative anti-HIV peptides from genome sequence scans. The in silica validation of these putative peptides through docking studies has shown that some of these AMPs may be involved in HIV/AIDS therapeutics and diagnostics. The molecular validation of these findings will be the way forward for the development of an early diagnostic tool and as a consequence initiate early treatment. This will prevent the invasion of the immune system by blocking the VIN2 domain and thus designing of a successful vaccine with broad neutralizing activity against this domain.
25

Metodologický pohled na měření (anti)imigračních postojů (kvalita měření se zaměřením na jeho ekvivalenci) / Measurement of (anti)immigration Attitudes from the Methodological Perspective. Quality of Measurement with the Special Focus on Measurement Equivalence

Šarapatková, Anna January 2019 (has links)
Opportunities that we have in today's world are sharply evolving, and the world is changing all together with these changes. This development is noticeably observed within the topic of global movement of (not only) population, which has changed fundamentally, both economically, politically and socially. Today's so much diversified form of migration, which has lost its transparency it used to has, is a very up to date and debated topic currently almost all over the world. Because of high importance of the topic "migration" it is often subject of research and number of surveys. One of the most examined area within the topic migration is attitudes of people towards immigration and immigrant, oftentimes together with investigating cause leading to particular attitude. Due to the international reach of the topic, these attitudes are often subject of cross-national research or national research, which, however, use data from international surveys. There is a clear disparity across European states in these attitudes towards immigration and, above all, the immigrants themselves. Given this nature of cross-national surveys measuring attitudes towards immigrants, it is important to focus on the measurement quality, which is becoming increasingly complex in the perspective of international research. It is...

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