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Articles 1 - 30 of 49
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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 …
Design Of Time-Phased Critical Path Scheduling Logic In Remanufacturing Material Requirements Planning, Gerald E. Tucker
Design Of Time-Phased Critical Path Scheduling Logic In Remanufacturing Material Requirements Planning, Gerald E. Tucker
Theses and Dissertations
This thesis develops and presents a new remanufacturing MRP time-phased scheduling algorithm utilizing a critical path concept, as in the project management field, for incorporation into remanufacturing production planning MRP calculations. The algorithm automates the remanufacturing lead time allowance calculation for child subassemblies and component parts in the form of Stack Time, and as such creates a linkage between the parent remanufacturing routing operation to which a remanufactured subassembly or component part is allocated for further processing, and the parent routing operation from which it is disassembled. This new MRP scheduling algorithm is optimal for calculating the total planned production …
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 …
The Asynchronous T-Step Approximation For Scheduling Batch Flow Systems, David R. Grimsman
The Asynchronous T-Step Approximation For Scheduling Batch Flow Systems, David R. Grimsman
Theses and Dissertations
Heap models in the max-plus algebra are interesting dynamical systems that can be used to model a variety of tetris-like systems, such as batch flow shops for manufacturing models. Each heap in the model can be identified with a single product to manufacture. The objective is to manufacture a group of products in such an order so as to minimize the total manufacturing time. Because this scheduling problem reduces to a variation of the Traveling Salesman Problem (known to be NP-complete), the optimal solution is computationally infeasible for many real-world systems. Thus, a feasible approximation method is needed. This work …
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 …
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, …
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 …
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 …
Modeling The Homeschool Timetabling Problem Using Integer Programming, Subhashini Srinivasan
Modeling The Homeschool Timetabling Problem Using Integer Programming, Subhashini Srinivasan
Theses and Dissertations
Home schooling has steadily been increasing in the past decade. According to a survey in 2007, about 2.5 million children were being home schooled in the US. Typically, parents provide education at the convenience of their home and in some cases an instructor is appointed for the same. The Home School Timetabling problem (HSTP) deals with assigning subjects, timeslots and rooms to every student. In doing so, there are certain hard and specialty constraints that are to be satisfied. Integer programming (IP) has been used in solving the HSTP as it has the advantage of being able to provide information …
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 …
Heuristic Approaches For Crane Scheduling In Ship Building, Charlie Hsiao Kuang Wen
Heuristic Approaches For Crane Scheduling In Ship Building, Charlie Hsiao Kuang Wen
Theses and Dissertations
This study provides heuristic approaches, including an ant colony optimization (ACO) inspired heuristic, to solve a crane scheduling problem that exists in most shipyards, where cranes are a primary means of processing and handling materials. Cranes move on a network of tracks, thus, blocking of crane movements is an issue. The crane scheduling problem consists of two major sub-problems: scheduling problem that determines the best overall order in which jobs are to be performed; the assignment problem that assigns cranes to jobs. The proposed heuristic consists of an Earliest Due Date sorting procedure in combination with an ACO assignment procedure …
Modeling Of An Adaptive Parallel System With Malleable Applications In A Distributed Computing Environment, Sheikh Khaled Ghafoor
Modeling Of An Adaptive Parallel System With Malleable Applications In A Distributed Computing Environment, Sheikh Khaled Ghafoor
Theses and Dissertations
Adaptive parallel applications that can change resources during execution, promise increased application performance and better system utilization. Furthermore, they open the opportunity for developing a new class of parallel applications driven by unpredictable data and events. The research issues in an adaptive parallel system are complex and interrelated. The nature and complexities of the relationships among these issues are not well researched and understood. Before developing adaptive applications or an infrastructure support for adaptive applications, these issues need to be investigated and studied in detail. One way of understanding and investigating these issues is by modeling and simulation. A model …
Use And Effectiveness Of Contract Schedule Incentives In Air Force Materiel Command, Rodrick A. Koch
Use And Effectiveness Of Contract Schedule Incentives In Air Force Materiel Command, Rodrick A. Koch
Theses and Dissertations
Are contract schedule incentives utilized by our acquisition contracting workforce, and if so what are their effectiveness? This research shows there is not widespread use of these types of incentives. There is also disagreement on their perceived effectiveness. Surveying, via email, the population of contracting officers and buyers within Air Force Materiel Command yielded responses from every center and many large acquisition systems. Only 8.5% of responses showed that they use schedule incentives. These respondents claim that schedule incentives are somewhat effective, yet of the 91.5 % that have not used them, 2-to-l say they would not be effective. The …
Data Analysis And Its Impact On Predicting Schedule & Cost Risk, Steven M. Cross
Data Analysis And Its Impact On Predicting Schedule & Cost Risk, Steven M. Cross
Theses and Dissertations
Many databases rely on documents (research) of the past to input data to create a comprehensive database. The Selected Acquisition Report (SAR) is one such document. The SARs are pervasive documents that have undergone decades of scrutiny by Congress and watchdog organizations such as the Government Accountability Office. Since the SAR has undergone such massive evolutionary changes, creating an accurate acquisition database presents a daunting task for the analyst and researcher alike. This research concerns itself with one such database. From this prior research database, we look to fill in missing data. We first conduct a literature review to determine …
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 …
Approximate Methods For Solving Flowshop Problems, Pramod Jain
Approximate Methods For Solving Flowshop Problems, Pramod Jain
Theses and Dissertations
The flow shop scheduling problem is a classical combinatorial problem being studied for years. The focus of this research is to study two variants of the flow shop scheduling problem in order to minimize makespan by scheduling n jobs on m machines. A solution approach is developed for the modified flow shop problem with due dates and release times. This algorithm is an attempt to contribute to the limited literature for the problem. Another tabu search-based solution approach is developed to solve the classical flow shop scheduling problem. This meta-heuristic (called 3XTS) allows an efficient search of the neighboring solutions …
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 …
Active Processor Scheduling Using Evolution Algorithms, David J. Caswell
Active Processor Scheduling Using Evolution Algorithms, David J. Caswell
Theses and Dissertations
The allocation of processes to processors has long been of interest to engineers. The processor allocation problem considered here assigns multiple applications onto a computing system. With this algorithm researchers could more efficiently examine real-time sensor data like that used by United States Air Force digital signal processing efforts or real-time aerosol hazard detection as examined by the Department of Homeland Security. Different choices for the design of a load balancing algorithm are examined in both the problem and algorithm domains. Evolutionary algorithms are used to find near-optimal solutions. These algorithms incorporate multiobjective coevolutionary and parallel principles to create an …
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 Group Theoretic Tabu Search Methodology For Solving The Theater Distribution Vehicle Routing And Scheduling Problem, John R. Crino
A Group Theoretic Tabu Search Methodology For Solving The Theater Distribution Vehicle Routing And Scheduling Problem, John R. Crino
Theses and Dissertations
The application of Group Theory to Tabu Search is a new and exciting field of research. This dissertation applies and extends some of Colletti's (1999) seminal work in group theory and metaheuristics in order to solve the theater distribution vehicle routing and scheduling problem (TDVRSP). This research produced a robust, efficient, effective and flexible generalized theater distribution model that prescribes the routing and scheduling of multi-modal theater transportation assets to provide economically efficient time definite delivery of cargo to customers. In doing so, advances are provided in the field of group theoretic tabu search and its application to difficult combinatorial …