Engineering Commons^™

Indentifying And Understanding User Preferences In Generic Planning Tools, Grisel Ventura

Open Access Theses & Dissertations

Planning is an important cognitive work activity. To support this complex task, the development of planning tools is important to support people during decision-making and problem-solving tasks. Nowadays, a large number of manual and electronic tools support this complex activity; manual and electronic planning tools aid people in creating strategies for effective work performance. However, there is limited information on the design of generic planning tools people use for their activities, and why people choose to use the planning tool they do. Some examples of generic tools for planning are calendars, checklists, agendas, etc.

To answer this question, this research …

Theoretical Exploratory Investigation On Reliability Of Advanced Ceramics By Discrete Element Simulation, Ana Laura Quezada Lara

Open Access Theses & Dissertations

The increasing application of silicon nitride in biomedical and other engineering fields has elevated the necessity to understand its reliability. Due to the complexity of producing pure material researchers have been analyzing the behavior of the material with flaws. In this thesis several scenarios are simulated with the support of PFC2D to analyze microcrack propagation depending on the position, quantity and size of the voids to understand the effect each of the cases have on the material. A four point bending test was applied to each case twice recording the loading force. Having two runs allows doing a statistical analysis …

Optimization Models For The Economic And Non-Economic Level Of Repair Analysis, Carlos Marco Ituarte-Villarreal

Open Access Theses & Dissertations

Every component, equipment or system will eventually fail. All failures produce a maintenance cost and, repair costs are especially hard to estimate ahead of time. Research shows that maintenance costs are the most substantial costs of development and use of equipment, reason why the cost of the product or equipment through its life is a major concern. Therefore, the main objective of this thesis is to provide a new optimization model to determine the minimum cost maintenance policy for complex systems.

Renewable Energy Integration: An Approach For Micro-Grid Optimization., Nicolas Lopez

Open Access Theses & Dissertations

This thesis explores the Renewable Energy Integration Problem beginning with a literature review on the different sources of electrical energy classified as Non-Renewable and Renewable, stating that the integration of renewable sources within the pre-existing Power-Grids is a current worldwide problem that is being addressed with different approaches.

The impossibility to exactly model the different equations relating the electric output of the renewable energy sources as they relate with meteorological factors, makes the renewable sector a stochastic component of the overall mathematical model, where it can be concluded that most of the problem is in the area of the forecast. …

Observer-Dependent Model For Analyzing Subjective Parameters In Epidemiology, Milad Zarei

Open Access Theses & Dissertations

Although medical technologies for preventing the contagion and spread of infectious diseases have improved steadily throughout the last century, new infectious diseases are still emerging and spreading swiftly. The modeling of infectious disease spread is crucial in addressing the lack of predictive ability in epidemiology. Managing the spread of infectious diseases requires processing quantitative epidemiological data and the ability to capture the dynamics of the infectious disease in order to provide a measure of control.

In this thesis, I have introducing cognitive biases in diseases spread modeling. For the first time, to the author's knowledge, the human subjective experience has …

Component Replacement Analysis For Electricity Distribution Systems Using Evolutionary Algorithms, Vasukumar Chenna

Open Access Theses & Dissertations

The main objective of the electric power grid is to supply economical and reliable electricity to industrial, commercial, household, transportation, and other end-users, including agricultural, educational institutions and hospitals. The power system is a very large and complex network consisting of generation, transmission, and distribution systems. The main focus of the present research is in the area of power distribution systems. Almost all the areas of the power grid uses simpler radial distribution systems to distribute electricity to the end consumer, it is the final and therefore vital link between the consumer and the rest of the power grid. Therefore …

E-Quality: Using Dimensional Index Values Towards Improving Classification Accuracy, Prashanth Devaram

Open Access Theses & Dissertations

E-quality is a process through which inspection of the process and quality of the part produced is done online resulting in the improvement of the process and reduction in the amount of time consumed for the overall process. Automated quality control involves using a methodology to classify the parts based on the dimensions of the features on a part. However, achieving 100% classification accuracy is not an easy task, especially in area of quality control where small differences in dimensions result in part fall into a different category. In this study, a novel approach for modifying the data before being …

Nondestructive Testing For Finding Out The Displacement Of Crack In Silicon Nitride, Sriharsha Kurra

Open Access Theses & Dissertations

Nondestructive testing (NDT) has become an increasingly vital factor in the effective conduct of research, development, design and manufacturing. Only with the appropriate use of nondestructive testing techniques, the benefits of advanced materials science can be fully realized. NDT has a wide range of industrial applications and various methods and techniques are employed to perform the nondestructive testing. The current work aims to demonstrate the nondestructive testing technique applied to determine the damage in silicon nitride. Ceramics are brittle materials and non destructive evaluation methods are required to assess the quality and reliability of them. A nondestructive evaluation technique has …

Multiple Objective Optimization Of Performance Based Logistics, Delia Villanueva

Open Access Theses & Dissertations

This thesis presents a new Performance Based Logistics optimization model. Performance Based Logistics (PBL) is becoming increasingly important for manufacturers in mission critical environments that need to provide ultimate product availability at the lowest cost and with the highest level of customer satisfaction. The U.S. Department of Defense has mandated that Performance Based Logistics programs be adopted by its major weapon systems and equipment suppliers, is one of the newest support strategies to improve the weapon system readiness. This work presents a new multiple objective evolutionary approach that simultaneously optimizes objectives such as Reliability, Maintainability and Total Cost for Ownership. …

Hybrid Approach For Site Selection Using Impact Assessment And Principal Component Analysis, Ugandhar Reddy Kondamadugula

Open Access Theses & Dissertations

Principle component analysis (PCA) is used to analyze week data of emission of particulate material from the Residential community. In this Thesis we selected five sites maps where sensors are arranged to collect particulate materials PM0.25, PM 10.Impact Assessment on the site areas are done in the first case,the results Impact Assessment on the site shows that the Global warming potential is really high at the site when the analysis is run for hundred years the Global warming potential has a very high impact on Environment leading to various health hazards. Secondly Principal Component Analysis is used to find out …

Retention And Productivity In Industrial Search And Scan Tasks, Camilo Aguilera

Open Access Theses & Dissertations

An experiment was developed in order to study the interaction between individual factors (gender and mood) and the retention ability in search and scan activities. 54 subjects between 18 and 30 years old participated in a computer-based memory test from the North of Mexico area. A full factorial design was used to analyze the variables. Two factors, one with two levels (gender: male and female), and the second factor with three levels (mood: positive, neutral, and negative) were used in the analysis. The output was measured as the amount of characters memorized in a string of random alphanumeric characters. Data …

Novel Approach To Predict The Crash Testing Data Using Multiple Regression Analysis And Principal Component Analysis, Ravi Lochan Kallur

Open Access Theses & Dissertations

In the design process of vehicles, crash tests are very critical to determine the safety measures. Every motor manufacturing company has to maintain certain standards for their autos. This will lead to the design optimization of safety measures utilizing the data available from crash tests. The engineers perform various experiments to generate data from crash testing of vehicles in their manufacturing facility. With the help of simulators; they create a virtual environment to perform design changes. Hence the data obtained from the crash tests is vital in design optimization of safety systems. The present study deals with the technologies involved …

Electric Power Distribution Optimization Using Evolutionary Algorithms, Sowmya Parimi

Open Access Theses & Dissertations

In the present research, a new evolutionary algorithm is developed to solve the component allocation problem in electricity distribution systems. The problem addresses the upgrade/design of an electricity distribution system with the objective of minimizing expected system downtime subject to cost and repair time constraints. The algorithm is tested on the Dual Element Spot Network (DESN) configuration which is one of the most commonly used configurations by the power industry. This algorithm is demonstrated with two examples.

Discrete Element Modelling Of Silicon Nitride Ceramics: Crack Formation And Propagation In Indentation Test And Four Point Bending Test, Rajeev Senapati

Open Access Theses & Dissertations

Advanced ceramic materials have been extensively used in aerospace, automobile and other industries. However, the reliability of the advanced ceramics is the major concern because of the brittle nature of the materials. This work aims to model silicon nitride ceramics using Discrete Element Method (DEM) and simulating the crack formation and propagation. DEM software package PFC2D is used to simulate indentation test and four point bending test on silicon nitride ceramics and the behaviour of crack formation and propagation is identified. The numerical representation of ceramic materials is done by generating a densely packed particle system using the specimen genesis …

Multi-Objective Network Reliability Optimization Using Evolutionary Algorithms, Franciso Oswaldo Aguirre

Open Access Theses & Dissertations

This work presents a new multiple objective evolutionary algorithm to solve three well known network reliability allocation problems considering different conflicting objectives to be optimized simultaneously. The new algorithm is applied in the design of a telecommunication network that is formed for several stations or nodes interconnected by telecommunication links or paths. The problem presented in this work involves finding which links to activate in order to obtain connectivity in the nodes. The number of nodes that need to be connected depends of the case that is being evaluated. The three network reliability problems considered are: all-terminal, k-terminal, and two-terminal. …

Optimization Of Flow For Plastic Pbt With 45% Glass And Mineral Fiber Reinforcement In An Injection Over Mold Process Using Taguchi, Cpk And Mold Flow Simulation Software Approaches, Israel Sanchez

Open Access Theses & Dissertations

This Thesis analyze the plastic injection molding parameters in order to identify which parameters significantly affects the flow properties of Polibuthylen Thereptalate with 45% glass/mineral reinforcement, and which levels are the best to use for those parameters. With the purpose of optimizing the plastic flow conditions in an injection mold to obtain parts free from short shots (term used to describe a plastic part that is incomplete due to the poor plastic flow in the mold runners and cavities).

The used approach is Taguchi design of experiments to define which parameters have significant effect on the response variable, and the …

Comparison Of Older Mexican American Upper Extremity Reach Capabilities To Older Anglo Americans, Odi Mike Ikpe

Open Access Theses & Dissertations

The study aimed to investigate if there are upper extremity reach capability differences in older Mexican Americans and older Anglo Americans. The subjects were recruited and corresponded to the 2000 census track. Upper extremity reach capability was determined by analysis of 20 range of motion variables. A MANOVA analysis utilizing SPSS software was performed with age, gender and ethnicity as independent variables while height and 20 range of motion anthropometric measurements servings as dependent variables (responses). Ethnicity as a function of age was found to be significant in height, horizontal distance from buttock to hand, rotation of head to the …

Using The Taguchi Design And The Central Composite Design To Increase The Robustness Of A Process From Its Raw Material Variability, Alvaro Cuevas

Open Access Theses & Dissertations

This research presents an experimental study where four controllable and one noise factor are analyzed using the Taguchi approach and the Central Composite Design (CCD) in order to induce robustness in a process that is being designed to treat residual grease from small restaurants. Three response variables are analyzed separately to establish the parameters conditions to obtain the most robust process output. These suggested conditions are validated conducting confirmation runs that are compared statistically to the predictions from the Taguchi prediction model for the Taguchi approach, and the Response optimizer for the CCD. The accuracy of each method is measured …

E-Quality Control: A Support Vector Machines Approach, Kalyan Reddy Aleti

Open Access Theses & Dissertations

The web-enabled quality control process presents many benefits to industry, such as universal access, remote control capability, and integration of production equipment into information networks for improved efficiency. This capability has a great potential, since engineers can access and control the equipment anytime, anywhere as the design stages evolve. In this context, this work uses innovative methods in remote part tracking and quality control with the aid of the modern equipment and application of Support Vector machine learning approach to predict the outcome of the quality control process. The classifier equations are built on the data obtained from the experiments …