S costs and Ao is significant if the predicted reliability goals are not met. / US Army (USA) author

Several computational applications in stochastic operations research are presented, where, for each application, a computational engine is used to achieve results that are otherwise overly tedious by hand calculations, or in some cases mathematically intractable. Algorithms and code are developed and implemented with specific emphasis placed on achieving exact results and substantiated via Monte Carlo simulation. The code for each application is provided in the software language utilized and algorithms are available for coding in another environment. The topics include univariate and bivariate nonparametric random variate generation using a piecewise-linear cumulative distribution, deriving exact statistical process control chart constants for non-normal sampling, testing probability distribution conformance to Benford's law, and transient analysis of M/M/s queueing systems. The nonparametric random variate generation chapters provide the modeler with a method of generating univariate and bivariate samples when only observed data is available. The method is completely nonparametric and is capable of mimicking multimodal joint distributions. The algorithm is "black-box," where no decisions are required from the modeler in generating variates for simulation. The statistical process control chart constant chapter develops constants for select non-normal distributions, and provides tabulated results for researchers who have identified a given process as non-normal The constants derived are bias correction factors for the sample range and sample standard deviation. The Benford conformance testing chapter offers the Kolmogorov-Smirnov test as an alternative to the standard chi-square goodness-of-fit test when testing whether leading digits of a data set are distributed according to Benford's law. The alternative test has the advantage of being an exact test for all sample sizes, removing the usual sample size restriction involved with the chi-square goodness-of-fit test. The transient queueing analysis chapter develops and automates the construction of the sojourn time distribution for the nth customer in an M/M/s queue with k customers initially present at time 0 (k ≥ 0) without the usual limit on traffic intensity, rho < 1, providing an avenue to conduct transient analysis on various measures of performance for a given initial number of customers in the system. It also develops and automates the construction of the sojourn time joint probability distribution function for pairs of customers, allowing the calculation of the exact covariance between customer sojourn times.

With the growing interest in the Marcellus Shale and its natural gas deposits, there are opportunities to purchase and hold land for investment purposes. A robust decision tool is needed to help guide investors towards the most profitable properties. Artificial neural networks have many unique benefits that make them an ideal candidate for this purpose. The artificial neural networks created in this study had nine independent variables. Combinations of these nine variables were created to describe 300 theoretical properties available for purchase. Each of these properties were then evaluated by an expert in the field and given a score from one to five to rate its investment potential, which was the dependent variable. Sixteen different network architectures were used to create over 200 neural networks. However, none of these networks met the criteria established to determine success. This is likely due to the unreliability in the data used to train the network, evidenced by the expert’s inability to reproduce previously assigned scores.

It has become customary in electrical engineering to think of signal processing in terms of voltage variables to the exclusion of current variables. This tendency has resulted in voltage signal processing circuits such as voltage-controlled voltage sources (VCVS) and voltage-mode operational amplifiers. However, the VCVS operational amplifier has several limitations which prevent high performance operation. One of these limitations is that the product of the closed loop -3dB bandwidth and the closed loop voltage gain is approximately a constant. Thus, for a typical internally compensated operational amplifier the closed loop -3dB bandwidth decreases as the closed loop voltage gain increases. By taking advantage of a current-controlled current source (CCCS) to form a current-mode operational amplifier, this limitation can be overcome. / Graduation date: 1991

Thesis (M.S. in Management) Naval Postgraduate School, Dec. 2001. / "December 2001." Thesis advisor(s): Thom W. Crouch, Keebom Kang. Includes bibliographical references (p. 121-123). Also available online.

Includes bibliographical references. / Fund managers and investors are confronted with the problem of selecting a single investment portfolio from a large number of possible combinations of available assets. In South Africa the set of possible portfolios has become even larger with the gradual relaxing of the constraints on foreign investment from 1995 to the present day, thereby expanding the investment universe for South African investors. Moreover, portfolio selection in South Africa is being transformed increasingly from being the exclusive domain of high net worth individuals, trustees and their investment managers to being the domain and responsibility of the man on the street. The Unit Trust industry started in South Africa in 1965 and gave the lower net worth individual a vehicle with which to invest in a diverse investment portfolio. This industry has proved very popular and has expanded from only 8 funds in 1980 to 338 funds and 136 billion rands under management in November 2000. Moreover the past two years, 1999 and 2000, has seen a change in the pension fund industry from defined benefit (DB) to defined contribution (DC) pension funds, transferring more of the risk and the responsibility of portfolio selection onto pension fund members. With increasing demand for fund management and investment advice by pension fund members and individual investors alike, the financial services industry in South Africa has also expanded. The consequent competition for assets of all descriptions have led, one hopes, to a more efficient market in equity, fixed income and derivative products. Thus modern portfolio theory has come a long way and will have to go further in meeting the demand to assist investors in their decision making.

Understanding team behaviors and dynamics are important to better understand and foster better teamwork. The goal of this master's thesis was to contribute to understanding and assessing teamwork in small group research, by analyzing motion dynamics and team performance with non-contact sensing and computational assessment. This thesis's goal is to conduct an exploratory analysis of motion dynamics on teamwork data to understand current limitations in data gathering approaches and provide a methodology to automatically categorize, label, and code team metrics from multi-modal data. We created a coding schema that analyzed different teamwork datasets. We then produced a taxonomy of the metrics from the literature that classify teamwork behaviors and performance. These metrics were grouped on whether they measured communication dynamics or movement dynamics. The review showed movement dynamics in small group research is a potential area to apply more robust computational sensing and detection approaches. To enhance and demonstrate the importance of motion dynamics, we analyzed video and transcript data on a publicly available multi-modal dataset. We determined areas for future study where movement dynamics are potentially correlated to team behaviors and performance. We processed the video data into movement dynamic time series data using an optical flow approach to track and measure motion from the data. Audio data was measured by speaking turns, words used, and keywords used, which were defined as our communication dynamics. Our exploratory analysis demonstrated a correlation between the group performance score using communication dynamics metrics, along with movement dynamics metrics. This assessment provided insights for sensing data capture strategies and computational analysis for future small group research studies.

The traditional acquisition and development cycles of a weapon system by government agencies go through multiple stages throughout the product's life cycle. Over the last few decades, much of the United States military equipment has experienced acquisition cost growth. Many studies by the Department of Defense indicate that the cost growth is a result of multiple factors, including the development and manufacturing stages of the product. Organizations with multiple operation sites across multiple states, countries, and continents find it increasingly difficult to share informational databases to ensure corporate synergy between multiple sites or divisions. For such organizations, there exists a need to synchronize the operations and have a standard and common database where all relevant design and product data is stored and equally accessed by different sites with proper authorization. In one way, Digital transformation sounds exotic and futuristic and promises to reduce the operating costs of big organizations. Digital Transformation remains a challenging proposition that requires investment to set up the infrastructure for such a system to operate successfully. Along with the initial setup cost of the system, there needs to be a change in the culture of running the business in each entity to have that much-needed synergy across the multiple divisions or sites. In this study, we will examine the effect of Digital Transformation in general and utilize the Digital Thread specifically to mitigate the risk of the cost growth of military programs.

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

The exposure of companies to turbulence, uncertainty, and vulnerability in their supply chain results in supply chain disruption with an estimate cost of $10 million for each supply chain disruption. The purpose of this case study was to explore the strategies supply chain managers use to mitigate supply chain disruption on business performance in a pharmaceutical company in Maryland. Contingency theory of fit formed the conceptual framework for this study. Participant perceptions were elicited in interviews with 11 supply chain managers regarding strategies to mitigate risks associated with supply chain disruptions. Data from interviews and supporting documents were processed and analyzed using data source triangulation to discern emergent themes. Three main themes emerged: (a) supply chain design, planning, and forecasting; (b) flexible and multiple supplier base; and (c) resource allocation and demand management. The implications for positive social change include the potential of reducing supply chain risk, which could lead to lower prices of products for consumers, increased stakeholder satisfaction, and a higher standard of living.