A major problem associated with air cargo transport is the assignment and scheduling of aircraft to routes that include several transloading points. This problem is complicated by the fact that shipping quantities vary at each terminal from one day to the next, and there are often wide fluctuations in demand for high priority cargo. Rapid delivery requirements calling for frequent flights to maintain satisfactory service often result in over-assignment and excess capacity. The balancing of capacity and service is a significant problem for air freight carriers. The problem investigated was to develop a means of evaluating various combinations of aircraft and route schedules taking into account the frequency of flights and the stochastic nature of shipping quantities. Key performance and cost variables were identified, and shipping data were analyzed to determine distribution parameters. A computer simulation model called CARGOSIM was developed to represent the air transport system and provide a tool for the evaluation of various alternatives. The simulation model allows for the stochastic behavior of cargo quantities and the detection of shipment delays due to random surges in demand. Accordingly, both the extent to which assigned aircraft can transport available cargo and the level of service at each terminal are determined through simulation. The simulation model is used in conjunction with a heuristic designed to search through aircraft types and flight frequency combinations until a least-cost solution is found. The cost function includes both the cost of operating the air transport system and the cost of service delays, thus a balance is achieved between capacity and service when an efficient solution is obtained. This feature represents a decision framework designed so that successive iterations of the simulation model will lead to a least-cost solution within statistically determined margins of error. / Ph. D.

This dissertation develops an economic equipment replacement model suitable for Flexible Manufacturing Systems (FMSs). An FMS represents an integrated machining system which produces multiple products and utilizes multiple inputs including avital materials handling system. The system's interactive nature defies traditional replacement works which are confined to one-for-one as well as like-for-like situations. The model developed in this work addresses the issue of multiple machine replacement. Considerations incorporated include layout, transportation, materials handling capacity, flexibility, capacity expansion/contraction, obsolescence and deterioration, inputs substitution, and equipment depreciation. This model is demand driven. The optimality criterion is the maximization of the after-tax future worth of the system at the end of a specified planning horizon. The 1983 ACRS rules are used. Illustrative examples are provided throughout. / Ph. D.

The purpose of this study was to propose and field test a cost-benefit analysis model to determine the profitability of secondary vocational education programs. The model consisted of costs, process, and benefits components. Instructional personnel, building, equipment, materials and supplies, administration, travel, services, utilities, and maintenance were the major components of the costs. Process implied the actual conduct of the program. Increased earnings from graduates' employment, earnings from cooperative placement, provision of services, and noneconomic benefits obtained by the graduates were the components of the benefits. Costs and benefits data for field testing the model were obtained from four programs from the four vocational service areas of trade and industrial, occupational home economics, business education, and marketing and distributive education selected from both a comprehensive high school and an area vocational education center in the Roanoke County School Division, Virginia. All graduates of 1983/84 of the four programs were surveyed to gather data on them. A 73.9% return was obtained from the survey. The difference between the graduates' current earnings and earnings determined by using the Federal minimum wage for the same number of work hours by employed graduates was considered as an income benefit. Actual differences between discounted benefits and the gross costs were used to determine the profitability of programs. The following conclusions were drawn from the findings of this study: 1. The trade and industrial, business education, and marketing and distributive education programs were economically profitable. 2. The occupational home economics program was not economically profitable. 3. Graduates in each program have obtained several noneconomic benefits. 4. The proposed cost-benefit analysis model was determined useable and transportable to other vocational education settings. Based on the findings and conclusions of this study, the following recommendations were drawn: 1. That local vocational administrative units use the concept of cost-benefit analysis as an evaluation technique for secondary vocational education programs. 2. That a research study be conducted to determine what other costs and benefits should be considered in the model. 3. That a research study be conducted to determine the economic value of noneconomic benefits. 4. That a longitudinal cost-benefit analysis is needed to determine economic earning and type of jobs held by graduates after graduation. 5. That a study be conducted using cost-benefit analysis with an appropriate comparison group to vocational graduates. 6. That an annual cost-benefit analysis of vocational programs be conducted for each school system to make comparative judgement of their programs. 7. That post-secondary vocational programs explore the possibility of using cost-benefit analysis for evaluating programs. / Ed. D.

Two types of heuristic capacity control policies a·re evaluated with a SLAM simulation model of a materials requirements planning production system. The control policy decisions are based solely on the size of the queue, as measured in standard hours of work, at each work center in the production system. Several classes of product mixes and product structures are investigated, as well as several levels of the control parameters of each control policy. The results indicate that each control policy gives rise to a unique population of weekly labor, work in process, and inventory level. Product structure is also identified as a major variable in Materials Requirements Planning systems performance. Sensitivity analysis of the cost functions for each policy indicate the conditions under which it will minimize the sum of labor costs, work in process holding costs, and inventory holding costs. The simulation model, MRPSIM, is included with a user's guide. / M.S.

Financial feasibility analysis is an essential component in the increasingly complex real estate development process. Participants in that process who expect to have an impact on the shape and nature of the built environment must develop a basic understanding of this form of analysis. This thesis will describe financial feasibility analysis, introduce a computer model that measures the financial performance of a proposed real estate development, and document the use of the computer model with a case study. It is a hoped that this thesis will be practical resource for the students. and faculty in the College. / M. Arch.

Educators considering implementing a computer simulation must decide on the optimum placement of the simulation in the unit of instruction to maximize student learning. This study examined student achievement using two different placements for the computer simulation, The Civil War, in a unit of instruction of 8th grade American History students in a suburban middle school.

Numerical simulations of waterjet inlets have been conducted in order to understand inlet performance during ship turning maneuvers. During turning maneuvers waterjet systems may experience low efficiency, cavitation, vibration, and noise. This study found that during turns less energy arrived at the waterjet pump relative to operating straight ahead, and that the flow field at the entrance of the waterjet pump exhibited a region of both low pressure and low axial velocity. The primary reason for the change in pump inflow uniformity is due to a streamwise vortex. In oblique inflow the hull boundary layer separates when entering the inlet and wraps up forming the streamwise vortex. These changes in pump inflow during turning maneuvers will result in increased unsteady loading of the pump rotor and early onset of pump rotor cavitation. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

A numerical study of fundamental aspects of turbulent mixing has been performed,with emphasis on the behavior of passive scalars of low molecular diffusivity (high Schmidt number Sc). Direct Numerical Simulation is used to simulate incompressible, stationary and isotropic turbulence carried out at high grid resolution. Data analyses are carried out by separate parallel codes using up to 1024^3 grid points for Taylor-scale Reynolds number (R_lambda) up to 390 and Sc up to 1024.Schmidt number of order 1000 is simulated using a double-precision parallel code in a turbulent flow at a low Reynolds number of R_lambda 8 to reduce computational cost to achievable level. The results on the scalar spectrum at high Schmidt numbers appear to have a k^{-1} scaling range. In the presence of a uniform mean scalar gradient, statistics of scalar gradients are observed to deviate substantially from Kolmogorov's hypothesis of local isotropy, with a skewness factor remaining at order unity as the Reynolds number increases. However, this skewness decreases with Schmidt number suggesting that local isotropy for scalars at high Schmidt number is a better approximation. Intermittency exponents manifested by three types of two-point statistics of energy and scalar dissipation, i.e., the two-point correlator (chi(x)chi(x+r)), the second-order moment of local scalar dissipation (chi_r^2) and the variance of the logarithmic local scalar dissipation sigma^2_{lnchi_r} are discussed. Several basic issues in differential diffusion between two scalars of different molecular diffusivities transported by the same turbule nt flow, the physical process of scalar spectral transfer and subgrid-scale transfer are also briefly addressed.

D. Tech. Electrical Engineering. / Aims of this study is to develop a residential customers' lighting profile ANFIS-based model. This model is expected to address lighting load usage estimation in relation to the dynamic occupancy presence in a residential dwelling, which will take into account the climatic condition (natural lighting) of such an environment (e.g. South Africa) and its income. The objectives are as follows: 1. Develop an ANFIS-based residential lighting load profile model for middle income, low income and high-income earners. 2. Error reduction in residential lighting demand profile model. Performance evaluation and validation of the model using correlation and trend analysis, regression model, South Africa power utility application lighting program, non-weighted approach and comparison with other research studies (methodology).3. Reduction in / or elimination of repeated models for occupant presence and assumptions that residences are occupied at certain periods. 4. Derive meaning from complexities (behavioural trends) associated with lighting usage and extract patterns in such circumstances.

D. Tech. Mechanical Engineering. / The level and quality of vibration experienced by motor vehicle occupants are issues of increasing concern and will probably be among the major challenges of the automotive industry in the twenty-first century. The vibration behaviour of door panels that enclose the passenger cabin can affect low-frequency noise in the cabin. This thesis presents the theory necessary for the development and simulation of a vibroacoustic door mount system and, thereafter, investigates its potential. Compared to the existing design, a perceivable noise reduction of 6.15 dB(A) was achieved by using the proposed sensitivity analysis procedure.