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Articles 61 - 90 of 103

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Districting And Dispatching Policies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems, Damitha Bandara Aug 2012

Districting And Dispatching Policies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems, Damitha Bandara

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The major focus of Emergency Medical Service (EMS) systems is to save lives and to minimize the
effects of emergency health incidents. The efficiency of the EMS systems is a major public concern. Thus,
over the past three decades a significant amount of research studies have been conducted to improve the performance
of EMS systems. The purpose of this study is also to improve the performance of EMS system.
The contribution of this research towards improving the performance of EMS systems is twofold. One area
is to implement optimal or near optimal dispatching strategies for EMS systems and the other …


Thermo-Mechanical Modeling Of The Electrically-Assisted Manufacturing (Eam) Technique During Open Die Forging, Wesley Salandro Aug 2012

Thermo-Mechanical Modeling Of The Electrically-Assisted Manufacturing (Eam) Technique During Open Die Forging, Wesley Salandro

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This thesis contains all of the steps which allow the Electrically-Assisted Manufacturing (EAM) technique to be experimentally explored and analytically modeled for an electrically-assisted forging operation. Chapter 1 includes the problem statement, proposed solution, and literature reviews on EAM. Chapter 2 describes a thorough background on the EAM technique, highlights prior EAM research, and explains the research approach taken for this thesis. The coupled thermo-mechanical modeling strategy, along with the introduction of the Electroplastic Effect Coefficient (EEC) is provided in Chapter 3. Chapter 4 explains the two different approaches to determine the EEC profiles when modeling a particular metal. The …


Prognostic And Health-Management Oriented Fuel Cell Modeling And On-Line Supervisory System Development, Xian Zhang Aug 2012

Prognostic And Health-Management Oriented Fuel Cell Modeling And On-Line Supervisory System Development, Xian Zhang

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Of the fuel cells being studied, the proton exchange membrane fuel cell (PEMFC) is viewed as the most promising for transportation. Yet until today, the commercialization of the PEMFC has not been widespread in spite of its large expectation. Poor long term performances or durability, and high production and maintenance costs are the main reasons. For the final commercialization of fuel cells in the transportation field, durability issues must be addressed, while costs should be further brought down. At the same time, health-monitoring and prognosis techniques are of great significance in terms of scheduling condition-based maintenance (CBM) to minimize repair …


Algebraic Approaches To Stochastic Optimization, Katherine Hastings May 2012

Algebraic Approaches To Stochastic Optimization, Katherine Hastings

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The dissertation presents algebraic approaches to the shortest path and maximum flow problems in stochastic networks. The goal of the stochastic shortest path problem is to find the distribution of the shortest path length, while the goal of the stochastic maximum flow problem is to find the distribution of the maximum flow value. In stochastic networks it is common to model arc values (lengths, capacities) as random variables. In this dissertation, we model arc values with discrete non-negative random variables and shows how each arc value can be represented as a polynomial. We then define two algebraic operations and use …


Research And Development Effort In Developing The Optimal Formulations For New Tablet Drugs, Zhe Li May 2012

Research And Development Effort In Developing The Optimal Formulations For New Tablet Drugs, Zhe Li

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Seeking the optimal pharmaceutical formulation is considered one of the most critical research components during the drug development stage. It is also an R&D effort incorporating design of experiments and optimization techniques, prior to scaling up a manufacturing process, to determine the optimal settings of ingredients so that the desirable performance of related pharmaceutical quality characteristics (QCs) specified by the Food and Drug Administration (FDA) can be achieved. It is widely believed that process scale-up potentially results in changes in ingredients and other pharmaceutical manufacturing aspects, including site, equipment, batch size and process, with the purpose of satisfying the clinical …


A Comprehensive Human Factors Analysis Of Off-Duty Motor Vehicle Crashes In The United States Military, Rebecca Iden May 2012

A Comprehensive Human Factors Analysis Of Off-Duty Motor Vehicle Crashes In The United States Military, Rebecca Iden

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Researchers have always had great interest in traffic safety and the phenomenon of motor vehicle crashes (MVCs). Though scores of service members are severely injured or killed in off-duty MVCs each year, few studies have addressed the MVC phenomenon within the military population and none have conducted a comprehensive evaluation of the causal factors associated with MVCs involving military personnel.
The main purpose of this dissertation was to gain a greater understanding of the causal factors associated with serious and fatal off-duty personal MVCs for military service members with the ultimate goal of preventing future losses. The HFACS-MVC framework was …


Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi Jan 2012

Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi

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This dissertation presents a scientific based approach for the analysis of folded sheet metal products. Such analysis initializes the examination in terms of topological exploration using set of graph modeling and traversal algorithms. The geometrical validity and optimization are followed by utilizing boundary representation and overlapping detection during a geometrical analysis stage, in this phase the optimization metrics are established to evaluate the unfolded sheet metal design in terms of its manufacturability and cost parameters, such as nesting efficiency, total welding cost, bend lines orientation, and maximum part extent, which aides in handling purposes. The proposed approach evaluates the design …


The Effects Of Weather Recognition Training On General Aviation Pilot Situation Assessment And Tactical Decision Making When Confronted With Adverse Weather Conditions, Chansik Kim Aug 2011

The Effects Of Weather Recognition Training On General Aviation Pilot Situation Assessment And Tactical Decision Making When Confronted With Adverse Weather Conditions, Chansik Kim

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Previous general aviation (GA) accident studies showed that decision errors were more associated with fatal GA accidents than other kinds of human errors, and weather related accidents, especially continued visual flight rules (VFR) flight into instrument meteorological conditions (IMC), remained the major cause of fatal GA accidents. Thus, finding the underlying causes of GA pilots' decision errors and continued VFR flight into adverse weather conditions are needed to reduce weather related GA accidents as well as fatal GA accidents.
Causal factors and hypotheses of weather related GA accidents show that knowledge, experience, motivation, and weather information frequently have been referred …


Metaheuristics For Hub Location Models, Ornurai Sangsawang Aug 2011

Metaheuristics For Hub Location Models, Ornurai Sangsawang

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In this research, we propose metaheuristics for solving two p-hub median problems.. The first p-hub median problem, which is NP-hard, is the uncapacitated single p-hub median problem (USApHMP). In this problem, metaheuristics such as genetic algorithms, simulated annealing and tabu search, are applied in different types of representations. Caching is also
applied to speed up computational time of the algorithms. The results clearly demonstrate that tabu search with a permutation solution representation, augmented with caching is the highest performing method, both in terms of solution quality and computational time among these algorithms for the USApHMP. We also investigate the performance …


Anticipating U.S. Population-Level Health And Economic Impacts Using Discrete-Event Simulation To Guide Health Policy Decisions, Odette Reifsnider Aug 2011

Anticipating U.S. Population-Level Health And Economic Impacts Using Discrete-Event Simulation To Guide Health Policy Decisions, Odette Reifsnider

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This dissertation presents two applications of discrete-event simulation (DES) to represent clinical processes: (1) a model to quantify the risk of the maternal obese and diabetic intrauterine environment influence on progression to adult obesity and diabetes, and (2) a model to evaluate health and economic outcomes of different smoking cessation strategies. The first application considers the public health impact of the diabetic and obese intrauterine environment's effect on the prevalence of diabetes and obesity across subsequent generations. We first develop a preliminary DES model to investigate and characterize the epidemiology of diabetes during pregnancy and birth outcomes related to maternal …


Improving Quality Of Service In Ems Systems By Reducing Disparities Between Service Zones, Sunarin Chanta Aug 2011

Improving Quality Of Service In Ems Systems By Reducing Disparities Between Service Zones, Sunarin Chanta

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Emergency medical service (EMS) systems respond to emergency or urgent calls so as to provide immediate care, such as pre-hospital care and/or transportation, to hospitals. Care must be provided in a timely manner; in fact quality of service is usually directly associated with response time. To reduce the response time, the number and location of vehicles within the service area are important variables. However with limited capacity, increasing the number of vehicles is often an infeasible alternative. Therefore, a critical design goal is to decide at which facilities stations should be located in order to serve as much demand as …


In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard May 2011

In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard

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The automotive marketplace is a volatile and dynamic system driven by consumer desires, marketing, fuel prices, technology, and legislation. Recently many of these factors have culminated in a common effort to encourage hybrid and electric vehicle development. The technology for electric vehicles has finally found enough maturity to be implemented into consumer based vehicles from hybrid SUVs to high performance sports cars. This expansion in available propulsion systems and vehicle architectures has spurred research and development into new and novel approaches for propulsion as well as systems to provide increased ride comfort.
This work presents a dual electric motor drive …


Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron May 2011

Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron

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The purpose of this study is to determine the effect of social pressure on general aviation (GA) pilots' weather decision making. Data have shown that GA accidents associated with visual flight rules (VFR) flight into instrument meteorological conditions (IMC) are more likely to result in fatalities than other types of GA accidents. This problem is compounded by the addition of passengers, who have been found to be present onboard during VFR into IMC accidents more frequently than in other types of GA accidents. The question is whether passengers influence a pilot's decision to continue flight into adverse weather. The extent …


Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals May 2011

Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals

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For quality engineering researchers and practitioners, a wide number of statistical tools and techniques are available for use in the manufacturing industry. The objective or goal in applying these tools has always been to improve or optimize a product or process in terms of efficiency, production cost, or product quality. While tremendous progress has been made in the design of quality optimization models, there remains a significant gap between existing research and the needs of the industrial community. Contemporary manufacturing processes are inherently more complex - they may involve multiple stages of production or require the assessment of multiple quality …


A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang May 2011

A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang

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This dissertation focuses on the use of passenger conveyance systems and modeling passenger flow in airport terminals. The successfully designed airport concourse must perform at a level that meets the needs of its users - the passengers. In this research, we propose a database design methodology that allows key conveyance statistics to be analyzed within specific locations across the airport terminal. Using passenger conveyance observations collected at five North American airports, the database enables airport planners, operators and consultants to assess passenger behavior and conveyance device performance. Results from this section of the research were in direct support of the …


Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens May 2011

Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens

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In metal injection molding (MIM), fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density.
The obstacle to sinter bonding a MIM part to a conventional (solid) substrate lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. It is …


Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry May 2011

Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry

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This research effort focuses on the acquisition of polyhedral outer-approximations to the convex hull of feasible solutions for mixed-integer linear and mixed-integer nonlinear programs. The goal is to produce desirable formulations that have superior size and/or relaxation strength. These two qualities often have great influence on the success of underlying solution strategies, and so it is with these qualities in mind that the work of this dissertation presents three distinct contributions.
The first studies a family of relatively unknown polytopes that enable the linearization of polynomial expressions involving two discrete variables. Projections of higher-dimensional convex hulls are employed to reduce …


A Meta-Analysis Of Human Factors Analysis And Classification System Causal Factors: Establishing Benchmarking Standards And Human Error Latent Failure Pathway Associations In Various Domains, Katherine Berry Dec 2010

A Meta-Analysis Of Human Factors Analysis And Classification System Causal Factors: Establishing Benchmarking Standards And Human Error Latent Failure Pathway Associations In Various Domains, Katherine Berry

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Many models of accident investigation have been created and have served as the basis for other tools and techniques. One of the most prominent techniques, Reason's Swiss Cheese Model (1990), is based on the idea of active and latent failures. Expanding on this idea, the Human Factors Analysis and Classification System (HFACS) was created with the idea to associate contributing factors and errors (Wiegmann & Shappell, 2003).
While HFACS has been frequently applied in the field of aviation in literature, other industry types are under-represented. Seventeen data sources encompassing various industry types were collected and included in this dissertation analysis. …


An Investigation Of Metaheuristics Using Path- Relinking On The Quadratic Assignment Problem, Thashika Rupasinghe Dec 2010

An Investigation Of Metaheuristics Using Path- Relinking On The Quadratic Assignment Problem, Thashika Rupasinghe

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The Quadratic Assignment Problem (QAP) is a widely researched, yet complex, combinatorial optimization problem that is applicable in modeling many real-world problems. Specifically, many optimization problems are formulated as QAPs. To resolve QAPs, the recent trends have been to use metaheuristics rather than exact or heuristic methods, and many researchers have found that the use of hybrid metaheuristics is actually more effective. A newly proposed hybrid metaheuristic is path relinking (PR), which is used to generate solutions by combining two or more reference solutions. In this dissertation, we investigated these diversification and intensification mechanisms using QAP. To satisfy the extensive …


Order Picking And Storage Using Stackable Pallets In A Warehouse, Ahmed Hassan Aly Dec 2010

Order Picking And Storage Using Stackable Pallets In A Warehouse, Ahmed Hassan Aly

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Quarter Billion dollars could be saved annually by double stacking pallets. A forklift storing 100 double stacked pallets saves 2.5 working hours versus single pallets. More than one billion pallets and cases handled between Wal-Mart distribution centers according to BEA White Paper (2006) [1], assume only 500 million were stackable pallets. This translates to 12.5 million working hours. If a forklift driver earns $20 per hour, then $250 million can be saved.
Moreover, handling double stacked pallets takes up to 46 % of total time to pick and store. This is a significant element that was ignored in literature. All …


Assortment Planning For Multiple Quality Levels Using Locational Choice, Mark Mcelreath Dec 2010

Assortment Planning For Multiple Quality Levels Using Locational Choice, Mark Mcelreath

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Assortment planning is the process in which a retailer selects a product line to offer to customers and is a key determinant of a retailer's profit. We consider the assortment planning problem using a locational choice model for customer product selection and allow for both horizontal and vertical product differentiation. When the distribution of customer preference is unimodal, the optimal solutions for this problem are unknown. We propose two solution philosophies for generating product assortments. First, we introduce a metaheuristic representation for the problem and test the performance of three metaheuristic techniques. We suggest that a tabu search or genetic …


Comprehensive Thermal Modeling Of Power Split Hybrid Power-Train And Electronics, Abdel Mayyas Dec 2010

Comprehensive Thermal Modeling Of Power Split Hybrid Power-Train And Electronics, Abdel Mayyas

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Hybrid electric vehicle (HEV) uses both internal combustion engine (ICE) with an electric system. The combination of the electric power train with the ICE is intended to achieve both better fuel economies than the conventional vehicles and better performance. Several types of HEV exist with different layouts. Recent HEVs' make use of regenerative braking, which converts the vehicles' kinetic energy into electric energy instead of wasting it as heat as conventional brakes do. A hybrid-electric is more fuel efficient than ICE and has less environmental impact.
The new HEV with its new Key Characteristics and Configurations (i.e. Mechanical complexity, Multiple …


Modeling Microbial And Nutrient Dynamics In Zero-Discharge Aquaculture Systems, Kendall Kirk Dec 2010

Modeling Microbial And Nutrient Dynamics In Zero-Discharge Aquaculture Systems, Kendall Kirk

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A finite element, finite difference model was developed to predict nutrient and microbial dynamics in recirculating aquaculture systems. Total ammonia nitrogen, nitrite, nitrate, chemical oxygen demand, and dissolved oxygen concentrations are predicted in addition to growth and decay of algae, Nitrosomonas, Nitrobacter, denitrifying heterotrophs, and aerobic heterotrophs. Inputs to the model include temperature, photosynthetically available radiation, feed application rate, pH, aeration/mixing energy, water exchange configuration, water exchange rate, tilapia biomass, and dissolved oxygen concentration. Up to 10 exchanged units may be included, user-definable as continuous stirred tank reactors or sequencing batch reactors. Demonstration of the model's utility was demonstrated through …


Simulation And Mathematical Modeling To Support Community-Wide Evacuation Decisions For Multiple Population Groups, Jun Duanmu Aug 2010

Simulation And Mathematical Modeling To Support Community-Wide Evacuation Decisions For Multiple Population Groups, Jun Duanmu

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Evacuating a large population from an at-risk area has been the subject of extensive research over the past few decades. In order to measure trip completion and total evacuation times accurately, most researchers have implemented some combination of simulation and optimization methods to provide vehicular flow and congestion data. While the general at-risk population comprises the majority of travelers on the road network, there are often specific groups to consider when assessing the ability to evacuate an entire population. In particular, healthcare facilities (e.g., hospitals) may require evacuation, and the trip times may become an important health issue for patients …


Principal Component Analysis Based Image Fusion Routine With Application To Stamping Split Detection, Yi Zhou Aug 2010

Principal Component Analysis Based Image Fusion Routine With Application To Stamping Split Detection, Yi Zhou

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This dissertation presents a novel thermal and visible image fusion system with application in online automotive stamping split detection. The thermal vision system scans temperature maps of high reflective steel panels to locate abnormal temperature readings indicative of high local wrinkling pressure that causes metal splitting. The visible vision system offsets the blurring effect of thermal vision system caused by heat diffusion across the surface through conduction and heat losses to the surroundings through convection. The fusion of thermal and visible images combines two separate physical channels and provides more informative result image than the original ones.
Principal Component Analysis …


Prioritizing Patients For Emergency Evacuation From A Healthcare Facility, Ashley Childers Aug 2010

Prioritizing Patients For Emergency Evacuation From A Healthcare Facility, Ashley Childers

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The success of a healthcare facility evacuation depends on communication and decision-making at all levels of the organization, from the coordinators at incident command to the clinical staff who actually carry out the evacuation. One key decision is the order in which each patient is chosen for evacuation. While the typical planning assumption is that all patients are to be evacuated, there may not always be adequate time or resources available to move all patients. In these cases, prioritizing or ordering patients for evacuation becomes an extremely difficult decision to make. These decisions should be based on the current state …


Estimation And Control Of Robotic Radiation-Based Processes, Fan Zeng Aug 2010

Estimation And Control Of Robotic Radiation-Based Processes, Fan Zeng

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This dissertation presents a closed-loop control and state estimation framework for a class of distributed-parameter processes employing a moving radiant actuator. These radiation-based processes have the potential to significantly reduce the energy consumption and environmental impact of traditional industrial processes. Successful implementation of these approaches in large-scale applications requires precise control systems. This dissertation provides a comprehensive framework for: 1) integration of trajectory generation and feedback control, 2) online distributed state and parameter estimation, and 3) optimal coordination of multiple manipulated variables, so as to achieve elaborate control of these radiation-based processes for improved process quality and energy efficiency.
The …


Human Error In Mining: A Multivariable Analysis Of Mining Accidents/Incidents In Queensland, Australia And The United States Of America Using The Human Factors Analysis And Classification System Framework, Jessica Patterson Dec 2009

Human Error In Mining: A Multivariable Analysis Of Mining Accidents/Incidents In Queensland, Australia And The United States Of America Using The Human Factors Analysis And Classification System Framework, Jessica Patterson

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Historically, mining has been viewed as an inherently high-risk industry. Nevertheless, the introduction of new technology and a heightened concern for safety has yielded marked reductions in accident and injury rates over the last several decades. In an effort to further reduce these rates, the human factors associated with incidents/accidents need to be addressed. A modified version of the Human Factors Classification and Analysis System (HFCAS-MI) was used to analyze lost time accidents and high-potential incidents from across Queensland, Australia and fatal accidents from the United States of America (USA) to identify human factor trends and system deficiencies within mining. …


An Investigation On The Use And Flexibility Of Genetic Algorithms For Logistic Regression, Sara Yoder Dec 2009

An Investigation On The Use And Flexibility Of Genetic Algorithms For Logistic Regression, Sara Yoder

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Social scientists and other users of large data sets often desire a model to predict the probability that some condition exists, such as the probability that a person has diabetes or that a credit card transaction will be fraudulent. In general, this can be done by data mining techniques, which allow multiple records of data composed of numerous independent variables and one dependent variable to be examined in a statistical fashion to make a predictive model. One particular technique used is logistic regression. Logistic regression forms a predictive model based on a set of independent variables by assigning coefficients to …


A Scanpath Comparison Of The Salient Features Of Weather Among General Aviation Pilots Based On Training And Experience, Michael Sawyer Dec 2009

A Scanpath Comparison Of The Salient Features Of Weather Among General Aviation Pilots Based On Training And Experience, Michael Sawyer

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Over the last 20 years the number of annual accidents in general aviation has seen a steady decline. The annual number of fatal accidents, however, has remained relatively stable. Adverse weather is consistently cited as a leading cause of fatal accidents in general aviation; weather accidents have a fatality rate nearly four times that of other general aviation accidents. Reviews of accident data reveal that often these accidents occur when inexperienced pilots who are certified only for visual flight rules flight continue into adverse weather. The Situation Assessment Hypothesis suggests these accidents occur when pilots fail to accurately recognize weather …