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7 pp. / In this publication, we will make the case of what Precision Agriculture (PA) technologies can do to enhance the productivity of farming systems, with particular attention to the case of irrigated agriculture in the semi-arid Arizona. This guide is intended to aid growers to select the right technology when considering the need to acquire new, or upgrade existing equipment.

A point process model for the packet stream arising in teletraffic processes is the discrete, non-negative integer-valued, stationary process introduced by Neuts and Pearce. In this thesis, we examine an empirical approach to develop a monitoring scheme for that point process. Monitoring is a procedure of tracking a stochastic process to identify quickly the development of anomalous situations in the evolution of that process and detect their assignable causes. Further, a data-analytic scheme to evaluate the order of a Markov chain that quantifies the local dependence embedded in the point process and Walsh spectral techniques are examined.

In this thesis, we consider determining the economic lot sizes for a finite production rate assembly system with n facilities. Costs at each facility consist of a stationary positive echelon holding cost, and a fixed set up cost. The goal is to determine the production lot size at each facility in order to minimize the long-run total average cost of the system. Power-of-two policies, in which the lot size at each facility is a power of two times some base lot size, are considered. A 94%-effective power-of-two policy is determined from the optimal solution to a continuous relaxation problem by an O(n) algorithm, while a 98%-effective power-of-two policy is found using an O(n log n) algorithm. Near optimal solutions to the continuous relaxation problem are found by a subgradient optimization procedure and a cyclic coordinate descent method. Computational results suggest both methods are efficient for very large systems.

This thesis compares three approaches for assigning workers and scheduling the flow of jobs in a Group Technology (GT) cell. The performance measure considered is the throughput time of jobs. The performance of the three strategies is analyzed by varying the following factors: (1) The ratio of Batch processing time to setup time. (2) Utilization. (3) The number of operators assigned to the cell. The scheduling strategies considered are Individual Machine Loading, Cell Dedication and Worker Batch Assignment. Analytical queueing models as well as computer simulations are used to compare the performance of the scheduling strategies. The dedicated cells perform best with large batch sizes and moderate workloads. The Worker Batch Assignment strategy does as well as traditional batch handling techniques with respect to the throughput time measure. This may be important since this kind of job assignment strategy has the advantage of augmenting quality (due to direct accountability) and enhancing morale without adversely impacting throughput times.