Dynamic inversion of underactuated systems via squaring transformation matrix

In this thesis, a novel method for control of non-square dynamical systems using a model following approach is developed. Control methodologies such as dynamic inversion and sliding mode control require an inversion of the input influence matrix. However, if the system input influence matrix is non-square direct inversion is not possible. Pseudo inversion of the input influence matrix may be performed for control allocation. However, pseudo inversion limits the control to states where the controller is directly applied. The pseudoinverse method does not permit the engineer to designate a particular state to control or track. When accurate tracking of states that are not directly controlled (“remaining states”) is required the pseudo inversion method is not useful. Current methods such as dynamic extension can be used to generate a square input influence matrix, essentially, creating an input influence matrix that is invertible. However, this method is tedious for large systems. In this work, a new transformation is applied to the original dynamical system model to develop an input influence matrix that is square. Assuming the system is controllable, the proposed transformation allows for accurate tracking of selectable states. Selection of the new transformation matrix is used to develop accurate tracking of certain states compared to the remaining states. A method based on optimal control theory is used to define the transformation matrix. The new approach is first applied to control a two mass system with simulation results presented showing the advantage of the proposed new control strategy. Finally, simulation results are presented for longitudinal control of an aircraft using one control input

Clustering and Classification of Multivariate Stochastic Time Series in the Time and Frequency Domains

The dissertation primarily investigates the characterization and discrimination of stochastic time series with an application to pattern recognition and fault detection. These techniques supplement traditional methodologies that make overly restrictive assumptions about the nature of a signal by accommodating stochastic behavior. The assumption that the signal under investigation is either deterministic or a deterministic signal polluted with white noise excludes an entire class of signals -- stochastic time series. The research is concerned with this class of signals almost exclusively. The investigation considers signals in both the time and the frequency domains and makes use of both model-based and model-free techniques. A comparison of two multivariate statistical discrimination techniques, one based on a traditional covariance statistic and one based on a more recently proposed periodogram based statistic, is carried out through simulation study. This investigation validates the utility of the periodogram based statistic over the covariance based statistic. The periodogram based statistic proves more useful in identifying statistical dissimilarities in multidimensional time series than the more traditional statistic. Attention is then focused on using the periodogram based statistic as a distance measure for clustering and classifying time series, which is motivated by the periodogram method\u27s increased discrimination capability. The test statistic is used in both clustering and classification algorithms, and the performance is evaluated though a simulation study. This measure proves capable of grouping like series together while simultaneously separating dissimilar series from one another. Finally, the techniques are adapted to the time-domain where they are used to cluster multidimensional, non-stationary, climatological data. The non-stationary model accounts for seasonal means, seasonal standard deviations, and stochastic components. The statistical approach results in the development of a level-α test for assessing signal equality. This improves upon typical dendrogram techniques by defining a level under which the distance should be considered zero. Climatological time series from the west coast, Gulf of Mexico, and east coast are analyzed using the aforementioned techniques. To complement the time series analysis work, some effort (Appendix A) is focused on improving the bachelor of science in the department of mechanical engineering via the undergraduate laboratories. This is accomplished by identifying desired outcomes and implementing specific improvements in the undergraduate laboratory courses over a period of four years. The effects of these improvements are quantified with survey results. Overall, the improvements are very well received and result in significant increases in student satisfaction

Molochansk Germans, Mennonites and the surroundings society: features of the land relationships

In article features of the land conflicts between ethnic Ger mans, Mennonites and the state peasants are considered. These conflicts can be divided into three types: conflicts resulting from incorrect demarcation of land, conflicts among ethnic groups and between them, conflicts with the government

Agricultural development in german-speaking settlements of the steppe zone of Southern Ukraine (mid-19th - early 20th century)

The article analyzes the issue of agricultural development of German-speaking colonists who lived in the steppe zone of Ukraine. The article analyzes the general features and main directions of development of this process and the reasons that caused it. The main attention is paid to the process of transformation of colonial agriculture. Until the 1860s, the most important and profitable branch of agriculture of the colonists was cattle breeding. However, due to rising grain prices, the importance of agriculture in Germanspeaking settlements is growing, which is now gradually becoming the basis of their economic development. Changing market needs have actually led to a complete restructuring of their internal structure. From now on it was reoriented to commodity production of grain crops. It was the need to achieve high profitability that forced colonists to use hired labor, agricultural machinery, and so on more widely than on other farms. This process also coincided with the widespread spread of colonial land tenure in the new territories of the region, which had an impact on certain changes in the natural environment. The methods of ecosystem analysis and synthesis used in our work are based on a comprehensive analysis of environmental components, identification of key factors in the functioning of an integrated agricultural system, identification of features that distinguish Mennonite colonies from others and determine the level of its uniqueness. The comparative research method is applied to the comparison of Mennonite agricultural landscapes with others. German-speaking colonists were the first to use 4 complete farming systems and actively used mineral and organic fertilizers. They carried out active reclamation work, for which cascades of ponds were created on the rivers. In the late 19th century, a number of publications noted the progressive agricultural methods of the colonists. This influenced the spread of progressive methods among other ethnic groups and denominations. In this way, the study of the historical experience of using nature makes it possible to assess the nature of the transformation of natural complexes, as well as to identify the features of the rationality of historical systems of nature management. Key words: agricultural machinery, agricultural implements, natural landscap

Altering textural properties of fermented milk by using surface-engineered Lactococcus lactis

Lactic acid bacteria are widely used for the fermentation of dairy products. While bacterial acidification rates, proteolytic activity and the production of exopolysaccharides are known to influence textural properties of fermented milk products, little is known about the role of the microbial surface on microbe-matrix interactions in dairy products. To investigate how alterations of the bacterial cell surface affect fermented milk properties, 25 isogenic Lactococcus lactis strains that differed with respect to surface charge, hydrophobicity, cell chaining, cell-clumping, attachment to milk proteins, pili expression and EPS production were used to produce fermented milk. We show that overexpression of pili increases surface hydrophobicity of various strains from 3-19% to 94-99%. A profound effect of different cell surface properties was an altered spatial distribution of the cells in the fermented product. Aggregated cells tightly fill the cavities of the protein matrix, while chaining cells seem to be localized randomly. A positive correlation was found between pili overexpression and viscosity and gel hardness of fermented milk. Gel hardness also positively correlated with clumping of cells in the fermented milk. Viscosity of fermented milk was also higher when it was produced with cells with a chaining phenotype or with cells that overexpress exopolysaccharides. Our results show that alteration of cell surface morphology affects textural parameters of fermented milk and cell localization in the product. This is indicative of a cell surface-dependent potential of bacterial cells as structure elements in fermented foods

Proceedings and Observations from a Climate Risks Event

In March 2015, in Delhi, India, CNA held a game and scenario-planning session in support of the Skoll Global Threats Fund and the United Kingdom's Foreign and Commonwealth Office. During the event, we explored the future effects of climate change as they relate to security around the world. Participants included renowned scientists, security experts, diplomats, and retired military personnel from Asia, Europe, the United Kingdom, and the United States. Based on game play and discussions, we identified four major findings: (1) climate change may increase nationalism and policies of internalization in developed countries; (2) large-scale climate-induced migration may impact a country's international policies, economic situation, and defining cultural attributes, changing the way they participate in global commons; (3) competition for limited resources may increase as a source of friction and shape policies and international relations; and (4) climate change technologies are not viewed in the same way by all countries, and there is potential for an emerging disparity between regions over the consensus and control of these technologies. This document gives an overview of the event and discusses why we identified each of these factors as a security risk that could result from climate change

Nonylphenol Polyethoxylates Enhance Adipose Deposition in Developmentally Exposed Zebrafish

Alkylphenol polyethoxylates (APEOs), such as nonylphenol ethoxylates (NPEOs), are high-production-volume surfactants used in laundry detergents, hard-surface cleaners, pesticide formulations, textile production, oils, paints, and other products. NPEOs comprise −80% of the total production of APEOs and are widely reported across diverse environmental matrices. Despite a growing push for replacement products, APEOs continue to be released into the environment through wastewater at significant levels. Research into related nonionic surfactants from varying sources has reported metabolic health impacts, and we have previously demonstrated that diverse APEOs and alcohol polyethoxylates promote adipogenesis in the murine 3T3-L1 pre-adipocyte model. These effects appeared to be independent of the base alkylphenol and related to the ethoxylate chain length, though limited research has evaluated NPEO exposures in animal models. The goals of this study were to assess the potential of NPEOs to promote adiposity (Nile red fluorescence quantification) and alter growth and/or development (toxicity, length, weight, and energy expenditure) of developmentally exposed zebrafish (Danio rerio). We also sought to expand our understanding of the ability to promote adiposity through evaluation in human mesenchymal stem cells. Herein, we demonstrated consistent adipogenic effects in two separate human bone-marrow-derived mesenchymal stem cell models, and that nonylphenol and its ethoxylates promoted weight gain and increased adipose deposition in developmentally exposed zebrafish. Notably, across both cell and zebrafish models we report increasing adipogenic/obesogenic activity with increasing ethoxylate chain lengths up to maximums around NPEO-6 and then decreasing activity with the longest ethoxylate chain lengths. This research suggests metabolic health concerns for these common obesogens, suggesting further need to assess molecular mechanisms and better characterize environmental concentrations for human health risk assessments