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Articles 1 - 30 of 31
Full-Text Articles in Engineering
Optimal Scheduling Of Aircraft Test And Evaluation Fleets To Balance Availability For Testing And Training, Sarah E. Hoops
Optimal Scheduling Of Aircraft Test And Evaluation Fleets To Balance Availability For Testing And Training, Sarah E. Hoops
Theses and Dissertations
The 96th Test Wing at Eglin Air Force Base manually schedules a fleet of approximately 26 aircraft to conduct a range of missions over a one-to-two year planning period. This study automates the scheduling process, does so in a manner that optimizes multiple planning goals related to aircraft availability for training, and provides the 96th Test Wing with a software tool for the implementation that can be used by operational analysts within the command. We formulate the scheduling problem as a multiobjective, nonlinear, binary integer math program that seeks to maximize both the lowest percent of time any aircraft is …
Development Of Minimum Delta-V Trajectories To Service Geo Assets From Cislunar Space, Alexander C. Urban
Development Of Minimum Delta-V Trajectories To Service Geo Assets From Cislunar Space, Alexander C. Urban
Theses and Dissertations
Orbits around Earth are becoming increasingly congested and contested, posing potential future threats to space assets. Cislunar space may offer an effective solution to these problems by offering storage for servicing and replacement vehicles. This investigation explores how to minimize the dV costs required of a network of service vehicles traveling from cislunar space to GEO using in-situ resource utilization. In this investigation the arc costs of an event-driven generalized multicommodity network flow are generated for creation of a model to be used to develop a dynamic scheduler. High-thrust trajectories between various inclinations of GEO, an Earth-Moon L1 Lyapunov orbit …
Assessment Of Some Of The Common Practices Used In Scheduling Highway Projects, Jennifer Reyes
Assessment Of Some Of The Common Practices Used In Scheduling Highway Projects, Jennifer Reyes
Theses and Dissertations
There are several factors documented in the literature that can affect the accuracy of estimated project durations in highway construction, such as weather, location, and soil conditions. Recently, the Texas Department of Transportation (TxDOT) raised a concern regarding some of the practices used when estimating the contract time for projects. This research presents an assessment of the effect that two practices identified have on the estimated project duration. These two practices include: 1) the estimated lead/lag times in project schedules and 2) scheduling with only critical or controlling activities. The effect of these practices is measured, primarily, by using four …
Large-Scale Non-Linear Dynamic Optimization For Combining Applications Of Optimal Scheduling And Control, Logan Daniel Beal
Large-Scale Non-Linear Dynamic Optimization For Combining Applications Of Optimal Scheduling And Control, Logan Daniel Beal
Theses and Dissertations
Optimization has enabled automated applications in chemical manufacturing such as advanced control and scheduling. These applications have demonstrated enormous benefit over the last few decades and continue to be researched and refined. However, these applications have been developed separately with uncoordinated objectives. This dissertation investigates the unification of scheduling and control optimization schemes. The current practice is compared to early-concept, light integrations, and deeper integrations. This quantitative comparison of economic impacts encourages further investigation and tighter integration. A novel approach combines scheduling and control into a single application that can be used online. This approach implements the discrete-time paradigm from …
Methods To Support The Project Selection Problem With Non-Linear Portfolio Objectives, Time Sensitive Objectives, Time Sensitive Resource Constraints, And Modeling Inadequacies, Neil C. Ranly
Theses and Dissertations
The United States Air Force relies upon information production activities to gain insight regarding uncertainties affecting important system configuration and in-mission task execution decisions. Constrained resources that prevent the fulfillment of every information production request, multiple information requestors holding different temporal-sensitive objectives, non-constant marginal value preferences, and information-product aging factors that affect the value-of-information complicate the management of these activities. This dissertation reviews project selection research related to these issues and presents novel methods to address these complications. Quantitative experimentation results demonstrate these methods’ significance.
The Developmental Test Scheduling Problem, Joseph E. Schoenbeck
The Developmental Test Scheduling Problem, Joseph E. Schoenbeck
Theses and Dissertations
Developmental testing of aircraft systems in the United States Air Force requires a complex set of resources for each test. The optimal scheduling of those resources is the job of the 412th Test Wing at Edwards Air Force Base. With more than 20 different Combined Task Forces requesting resources for roughly 300 flying missions each week, manual scheduling is a difficult task. The current process takes a team of schedulers several days to get a workable result from which they can start tailoring the final schedule. While concepts and techniques can be taken from industry scheduling problems, the body of …
Impact Of Critical Path Method (Cpm) Of Scheduling On On-Time Completion Of Transportation Projects, Fahim Ahmed
Impact Of Critical Path Method (Cpm) Of Scheduling On On-Time Completion Of Transportation Projects, Fahim Ahmed
Theses and Dissertations
This study addresses the effectiveness of Critical Path Method (CPM) scheduling on project delivery. Specifically, the on-time completion of projects with and without a CPM schedule is explored. The paper uses data from 2,097 South Carolina transportation projects let after February 2008 and substantially completed by August 2015. The delay analysis uses the original contract completion date as well as the completion date adjusted by change orders. Chi-Squared tests are used to examine the relationship between CPM scheduled projects and delayed projects, and t-tests are used to compare the mean delay (in days) between CPM scheduled and unscheduled projects. The …
Project Management: Skills, Tools, And Knowledge Construction Professionals Consider Important For Keeping Projects On Schedule, Lyle Scott Davies
Project Management: Skills, Tools, And Knowledge Construction Professionals Consider Important For Keeping Projects On Schedule, Lyle Scott Davies
Theses and Dissertations
Project managers have a major role in the construction and completion of projects. Much of their work consists of reviewing, clarifying, and coordinating information required by the field management and subcontractors performing the work on the job site. The assistance they give with the transfer of information helps with successfully completing projects. For many people, the largest indicator that a project was successful is that construction activities were completed on schedule. While finishing on schedule may be the primary focus of those involved with construction activities, projects still struggle to finish on time. The purpose of this study is to …
Sortie Generation Simulation Of A Fighter Squadron, Abdurrahman Sevimli
Sortie Generation Simulation Of A Fighter Squadron, Abdurrahman Sevimli
Theses and Dissertations
The Turkish Air Force utilizes several fighter squadrons to enhance its military capabilities. One of the most critical challenges for these squadrons is generating sorties to meet the currency and demand during both peacetime and wartime. This sortie generation process directly affects the success of both training and operations. In this study, this process is assessed using a discrete event simulation. Air Force decision makers require a simulation tool to conduct “what-if” analysis on how potential changes in the environment affect an F-16 fighter squadron’s sortie generation process. Creating a usable simulation provides decision makers with a flexible tool to …
Increased Capacity Utilizing Aggregation And Consolidation Of Contingency Cargo, Cassidy L. Wilson
Increased Capacity Utilizing Aggregation And Consolidation Of Contingency Cargo, Cassidy L. Wilson
Theses and Dissertations
Maximizing use of limited airlift assets is a common problem during large contingency operations. Requirements often exceed airlift capacity and fiscal constraints driving the need to aggregate conveyance loads both within and across business lines (Unit Line Number (ULN), Special Assignment Airlift Mission (SAAM), and sustainment). Current methods of consolidation are completed by planners at the 618th Air Operations Center. This process is completed by piecing email correspondence and making individual localized decisions which are not always consistent with big picture efficiency. United States Transportation Command requested a study to create standard business rules or a methodology that can benefit …
Forensic Schedule Analysis Of Construction Delay In Military Projects In The Middle East, James W. Forbes
Forensic Schedule Analysis Of Construction Delay In Military Projects In The Middle East, James W. Forbes
Theses and Dissertations
This research performs forensic schedule analysis of delay factors that impacted recent large-scale military construction projects in the Middle East. The purpose of this study is to understand the most significant causes of project delay and how AFCEC might improve schedule management performance. The methodologies for analysis are adapted from the Professional Practice Guide to Forensic Schedule Analysis, particularly Method 3.7 Modeled/Additive/Multiple Base, or Time Impacted Analysis—Adjusted. The data is gathered from USACE and AFCEC, consisting of Primavera project schedules and project documents from the Resident Management System database. The project delays from two large-scale projects are apportioned as compensable, …
Scheduling Of Container Handling Equipment In Marine Container Terminals, Narges Kaveshgar
Scheduling Of Container Handling Equipment In Marine Container Terminals, Narges Kaveshgar
Theses and Dissertations
To improve the competitiveness of marine container terminals, it is critical to minimize the makespan of a container vessel. The makespan is defined as the latest completion time among all handling tasks of the container vessel. Lower makespan (i.e. lower vessel turn time) can be achieved through better scheduling of the container handling equipment during vessel operations. The scheduling of terminal equipment is an operational problem, and a detailed schedule for each type of equipment operating in the terminal is necessary. Several studies have applied operations research techniques to optimize the processes of equipment in a terminal. This dissertation investigates …
Heuristic Algorithms To Minimize Total Weighted Tardiness On The Single Machine And Identical Parallel Machines With Sequence Dependent Setup And Future Ready Time, Yue Xi
Theses and Dissertations
This study generates heuristic algorithms to minimize the total weighted tardiness on the single machine and identical parallel machines with sequence dependent setup and future ready time. Due to the complexity of the considered problem, we propose two new Apparent Tardiness Cost based (ATC-based) rules. The performances of these two rules are evaluated on the single machine and identical parallel machines. Besides of these two rules, we also propose a look-ahead identical parallel machines heuristic (LAIPM). When a machine becomes idle, it selects a job to process from available jobs and near future jobs. The proposed method, LAIPM, is evaluated …
Vehicle Minimization For The Multimodal Pickup And Delivery Problem With Time Windows, Benjamin A . Clapp
Vehicle Minimization For The Multimodal Pickup And Delivery Problem With Time Windows, Benjamin A . Clapp
Theses and Dissertations
The algorithm proposed here is used for heuristic solutions for the Multimodal Multiple Vehicle Routing Problem with Unloading Capacity, Pickup and Dropoff, and Time Windows, solved so as to minimize the number of vehicles used, subject to varying objective function values for each vehicle. The MVRP is simplified and split into a routing problem and a scheduling problem. The routing problem is addressed by Dijkstra's Algorithm. This generates a new network for the second stage of the algorithm. It is assumed that the shortest path is the correct path to use, and shipments each travel unimodally. The scheduling problem is …
The Pulled-Macro-Dataflow Model: An Execution Model For Multicore Shared-Memory Computers, Daniel Joseph Richins
The Pulled-Macro-Dataflow Model: An Execution Model For Multicore Shared-Memory Computers, Daniel Joseph Richins
Theses and Dissertations
The macro-dataflow model of execution has been used in scheduling heuristics for directed acyclic graphs. Since this model was developed for the scheduling of parallel applications on distributed computing systems, it is inadequate when applied to the multicore shared-memory computers prevalent in the market today. The pulled-macro-dataflow model is put forth as an alternative to the macro-dataflow model, having been designed specifically to accurately describe the memory bandwidth limitations and request-driven nature of communications characteristic of today's machines. The performance of the common scheduling heuristics DSC and CASS-II are evaluated under the pulled-macro-dataflow model and it is shown that their …
Project Scheduling To Maximize Positive Impacts Of Reconstruction Operations, Andrew D. Chaney
Project Scheduling To Maximize Positive Impacts Of Reconstruction Operations, Andrew D. Chaney
Theses and Dissertations
Since the decline of the Cold War, the risk of major conflict between powerful industrialized nations has significantly decreased. Insecurity in the twenty-first century is forecast to arise rather from the debris of imploding states. Such situations may require intervention | military or otherwise | by concerned states, and the frequency with which these interventions occur is increasing. To meet this new operational challenge, the US military must adapt its planning procedures to account for Security, Stabilization, Transition, and Reconstruction Operations (SSTRO). This research develops a project scheduling based framework for post-conflict reconstruction that prioritizes and schedules reconstruction activities in …
Improving Intercontinental Ballistic Missile Maintenance Scheduling Through The Use Of Location Analysis Methodologies, Dale L. Overholts Ii
Improving Intercontinental Ballistic Missile Maintenance Scheduling Through The Use Of Location Analysis Methodologies, Dale L. Overholts Ii
Theses and Dissertations
The events of September 11, 2001 have led to increased security requirements for all ICBM-related activities. Missile maintenance managers must explore new scheduling techniques to sustain weapon system readiness levels in light of published security enhancements. The problem of improving missile maintenance scheduling is modeled as a two-stage heuristic that utilizes the maximal covering location problem methodology. Maintenance activities are categorized and weighted according to published priority designation and mission impact. The model’s first stage seeks to select two security umbrellas that maximize the weighted sum of maintenance activities. Stage two seeks to determine a maintenance schedule comprised of launch …
Comparing F-16 Maintenance Scheduling Philosophies, Konstantinos Iakovidis
Comparing F-16 Maintenance Scheduling Philosophies, Konstantinos Iakovidis
Theses and Dissertations
In the F-16 fighter community it is believed that the flying schedule can make or break a wing's maintenance effort. Nevertheless, there is no published scientific support behind many commonly used maintenance scheduling philosophies. The problem is that a generally accepted overall scheduling philosophy to improve the long term health of the fleet does not exist. The purpose of this research is tri-fold: to identify the most important scheduling philosophies, to identify the most meaningful metrics that capture the long term health of the fleet and maintenance effectiveness, and to compare the various philosophies using the performance measures to help …
Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha
Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha
Theses and Dissertations
In the U.S. Air Force, a Logistic Readiness Squadron (LRS) provides material management, distribution, and oversight of contingency operations. Dispatchers in the LRS must quickly prepare schedules that meet the needs of their customers while dealing with real-world constraints, such as time windows, delivery priorities, and intermittent recurring missions. Currently, LRS vehicle operation elements are faced with a shortage of manpower and lack an efficient scheduling algorithm and tool. The purpose of this research is to enhance the dispatchers' capability to handle flexible situations and produce "good" schedules within current manpower restrictions. In this research, a new scheduling model and …
A Combined Adaptive Tabu Search And Set Partitioning Approach For The Crew Scheduling Problem With An Air Tanker Crew Application, Todd E. Combs
A Combined Adaptive Tabu Search And Set Partitioning Approach For The Crew Scheduling Problem With An Air Tanker Crew Application, Todd E. Combs
Theses and Dissertations
This research develops the first metaheuristic approach to the complete air crew scheduling problem. It develops the first dynamic, integrated, set-partitioning based vocabulary scheme for metaheuristic search. Since no benchmark flight schedules exist for the tanker crew scheduling problem, this research defines and develops a Java™ based flight schedule generator. The robustness of the tabu search algorithms is judged by testing them using designed experiments. An integer program is developed to calculate lower bounds for the tanker crew scheduling problem objectives and to measure the overall quality of solutions produced by the developed algorithms.
A Multiple Ant Colony Metaheuristic For The Air Refueling Tanker Assignment Problem, Ronjon Annaballi
A Multiple Ant Colony Metaheuristic For The Air Refueling Tanker Assignment Problem, Ronjon Annaballi
Theses and Dissertations
The performance of the Nuclear Facility (NFAC) incident module in modeling a nuclear reactor accident is evaluated. Fallout predictions are compared with air concentration measurements of I-131 in Europe over a five-day period. Two categories of source term specifications are used: NFAC-generated source terms based on plant conditions and accident severity, and user-defined source terms based on specifying the release of I-131. The Atmospheric Transport Model Evaluation Study report source term provided the needed detailed release information. The Air Force Combat Climatology Center provided weather data covering Europe during the release's 11-day duration. For the NFAC-generated source terms as few …
An Interactive Decision Support System For Scheduling Fighter Pilot Training, Cuong T. Nguyen
An Interactive Decision Support System For Scheduling Fighter Pilot Training, Cuong T. Nguyen
Theses and Dissertations
The U.S. Air Force is developing Modular Aircraft Support System (MASS) program to replace the current Aerospace Ground Equipment (AGE). AGE supplies electricity, nitrogen, hydraulics and other support equipment to maintenance activities at the flight line. Current AGE makes up one-third of the deployment footprint. AGE is also mostly aircraft specific, and has reliability problems. The MASS alternative focuses on modularity based on a plug-and-play approach. The technological improvements and possible reduction in the footprint make MASS a good alternative. The AF has to determine now, whether MASS can supply similar functionality and decrease the deployment footprint to theater, while …
Effects Of Shiftwork On Air Force Aircraft Maintenance Personnel, Craig A. Campbell
Effects Of Shiftwork On Air Force Aircraft Maintenance Personnel, Craig A. Campbell
Theses and Dissertations
This study examined the effects of converting a large aircraft maintenance squadron from 8-hour shifts to 12-hour shifts. The squadron studied converted its 24- hour maintenance work force from three 8-hour work shifts to two 12-hour work shifts incrementally, with one section converting to 12-hour shifts in January, 1996, and the remaining section converting in July, 1996. Both sections remained on 12-hour shifts until September, 1997, when both sections converted back to a three shift 8-hour operation. Health and well being, on- and off-duty accident rates, day shift vs. night shift accident rates, and the effects of stress and fatigue …
The Scheduling Process In A Depot From The Brazilian Air Force, Fabricio J. Saito
The Scheduling Process In A Depot From The Brazilian Air Force, Fabricio J. Saito
Theses and Dissertations
The Brazilian Air Force (BAF) in its logistic structure contains 5 Air Logistic Centers (depots). This thesis concentrates its analysis on one of the most important BAF depots located at Sao Paulo (PAMASP). This thesis explores the scheduling process currently used in PAMASP. This thesis adopted a managerial approach in a sense that it looked to take a big picture of the current process. The researcher performed field interviews with the goal of describing the process. During the visit to PAMASP, the researcher also gathered problems related to the process. The recommendations stated on this study were based on the …
A Value Focused Thinking Approach To Academic Course Scheduling, Shane A. Knighton
A Value Focused Thinking Approach To Academic Course Scheduling, Shane A. Knighton
Theses and Dissertations
In 1997, the School of Engineering of the United States Air Force Institute of Technology began exploring ways of automating the academic course scheduling process. The administration desired an expedient approach for course scheduling which supports the institute's mission of "providing scientific and technological education" to officers from all branches of military service, as well as international military forces. The scheduling approach needed to be flexible, efficient, and represent the institute's values and principles. Decision Analysis (DA) and specifically, Value Focused Thinking (VFT), is used to decompose the complex problem of academic course scheduling and determine the factors that are …
Scheduling And Sequencing Arrivals To A Stochastic Service System, Peter M. Vanden Bosch
Scheduling And Sequencing Arrivals To A Stochastic Service System, Peter M. Vanden Bosch
Theses and Dissertations
Optimization of scheduled arrival times to an appointment system is approached from the perspectives of both queueing and scheduling theory. The appointment system is modeled as a one-server, first-come-first-served, transient queue with independent, distinctly distributed service times and no-show rates. If a customer does show, it is assumed to be punctual. The cost of operating the appointment system is a convex combination of customers' waiting times and the server's overtime. While techniques for finding the optimal static and dynamic schedules of arrivals have been proposed by other researchers, they mainly have focused on identical customers and strictly punctual arrivals. This …
Crisis Airlift Management: Effective Scheduling, David C. Penny
Crisis Airlift Management: Effective Scheduling, David C. Penny
Theses and Dissertations
This is a report on the basis, data, findings, and models developed for US Transportation Command and Headquarters Air Mobility Command. Focusing on the dynamic scheduling problem that arises during management of airlift assets into space-constrained airfields during a crisis, this research explains the conditions surrounding this event, discusses several areas of potential cross-functional applications, presents analysis of current performance, and provides several modeling possibilities for schedule efficiency. Past research in the Flow Management Problem (an airline flow control issue) is extensive, but specific applications in crisis airlift are long in coming, primarily due to the complexity of the environment. …
Procedures For Testing Deterministic Scheduling Models: A Dakota Case Study, Keith H. Mccready
Procedures For Testing Deterministic Scheduling Models: A Dakota Case Study, Keith H. Mccready
Theses and Dissertations
The DAKOTA scheduling system has been proposed for use in the United States Air Forces Europe's (USAFE's) Operational Support Airlift (OSA) scheduling. This thesis examines the OSA scheduling topic and reviews the relevant literature on vehicle routing, concluding that exact methods are intractable for large problem sizes. Consequently, heuristic methods must be considered. This thesis takes a detailed look at the DAKOTA heuristic. It examines the concepts of Validation, Verification and Accreditation (VV&A), particularly as they apply to heuristics and algorithms. It then defines what measures of performance may prove useful in judging heuristics and algorithms in general, and details …
An Improved Heuristic For Intercontinental Ballistic Missile Crew Scheduling, Michael D. Shirley Jr.
An Improved Heuristic For Intercontinental Ballistic Missile Crew Scheduling, Michael D. Shirley Jr.
Theses and Dissertations
Creating monthly schedules for missile crews is a complex and time-consuming problem. Thousands of events must be scheduled for several hundred missile officers. The rules and regulations governing the problem are numerous, and there are currently no established measures for missile crew schedules. The scheduling software currently available only schedules a fraction of the events. The objectives of this research were to create a rule-based heuristic which could quickly produce feasible or near-feasible schedules, to make the scheduling process paperless, and to develop possible measures of effectiveness for missile crew schedules. The research was successful in each of these areas. …
Automating Satellite Range Scheduling, S. Michael Schalck
Automating Satellite Range Scheduling, S. Michael Schalck
Theses and Dissertations
The objective of this study was to develop a computer based satellite range scheduling SRS algorithm to create a 24 hour satellite support schedule. The algorithms goal was to schedule as many satellite support requests as possible. An iterative heuristic approach was used to schedule satellite support requests in three successive sub problems. The first sub problem involves scheduling low altitude satellite support requests using a mixed integer programming approach. The next two sub problems each involve scheduling 12 hour blocks of medium and high altitude satellite support requests, again using a mixed integer programming approach. Fourteen 24 hour schedules …