529 research outputs found
Time Series Forecasting and Analysis: A Study of American Clothing Retail Sales Data
This paper serves to address the effect of time on the sales of clothing retail, from 2010 to May 2019. The data was retrieved from the US Census, where N=113 observations were used, which were plotted to observe their trends. Once outliers and transformations were performed, the best model was fit, and diagnostic review occurred. Inspections for seasonality and forecasting was also conducted. The final model came out to be an ARIMA (2,0,1). Slight seasonality was present, but not enough to drastically influence the trends. Our results serve to highlight the economic growth of clothing retail sales for the past 8 years, cementing the significance of the production economy\u27s stability. The quarterly GDP data was collected in order to find out the relationship with the differenced clothing data. Some observations of GDP data were affected by the clothing data before removing the seasonality. After removing the seasonality, the clothing expense is white noise and not predictable from the historical GDP
Optimal orbit transfers for satellite formation flying applications
Title from PDF of title page (University of Missouri--Columbia, viewed on July 29, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Craig A. KlueverIncludes bibliographical references.Vita.Ph. D. University of Missouri--Columbia 2012."July 2012"This dissertation focused on trajectory optimization problems arising from the application of satellite formation flying, and obtained three major results. First, the dissertation proposed an algorithm for finding a multi-impulse, fuel-optimal trajectory, based on relative motion dynamics, and the necessary conditions from the Pontryagin Maximal Principle. Second, the dissertation derived sufficient conditions, verifying the optimality of the impulsive trajectories obtained in the first part. Third, the dissertation presented an analytic linearization method, termed the “primer vector approximation method,” for solving nonlinear continuous-thrust trajectory optimization problems.Includes bibliographical reference
Inequalities for generalized matrix function and inner product
We present inequalities related to generalized matrix function for positive
semidefinite block matrices. We introduce partial generalized matrix functions
corresponding to partial traces and then provide an unified extension of the
recent inequalities due to Choi [6], Lin [14] and Zhang et al. [5,19]. We
demonstrate the applications of a positive semidefinite block
matrix, which motivates us to give a simple alternative proof of Dragomir's
inequality and Krein's inequality.Comment: 12 pages. This paper was originally written on Nov. 02, 2019;
Recently, we make a new revision. Any commennts are wellcom
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