3 research outputs found
STRATEGIES TO IMPROVE THE EFFICIENCY OF EMERGENCY MEDICAL SERVICE (EMS) SYSTEMS UNDER MORE REALISTIC CONDITIONS
Emergency medical service (EMS) systems provide medical care to pre-hospital patients who need rapid response and transportation. This dissertation proposes a new realistic approach for EMS systems in two major focuses: multiple unit dispatching and relocation strategies. This work makes recommendations for multiple-unit dispatch to multiple call priorities based on simulation optimization and heuristics. The objective is to maximize the expected survival rate. Simulation models are proposed to determine the optimization. A heuristic algorithm is developed for large-scale problems. Numerical results show that dispatching while considering call priorities, rather than always dispatching the closest medical units, could improve the effectiveness of EMS systems. Additionally, we extend the model of multiple-unit dispatch to examine fairness between call priorities. We consider the potentially-life-threatening calls which could be upgraded to life-threatening. We formulate the fairness problem as an integer programming model solved using simulation optimization. Taking into account fairness between priorities improves the performance of EMS systems while still operating at high efficiency. As another focus, we consider dynamic relocation strategy using a nested-compliance table policy. For each state of the EMS systems, a decision must be made regarding exactly which ambulances will be allocated to which stations. We determine the optimal nested-compliance table in order to maximize the expected coverage, in the binary sense, as will be later discussed. We formulate the nested-compliance table model as an integer program, for which we approximate the steady-state probabilities of EMS system to use as parameters to our model. Simulation is used to investigate the performance of the model and to compare the results to a static policy based on the adjusted maximum expected covering location problem (AMEXCLP). Additionally, we extend the nested-compliance table model to consider an upper bound on relocation time. We analyze the decision regarding how to partition the service area into smaller sub-areas (districts) in which each sub-area operates independently under separate relocation strategies. We embed the nested-compliance table model into a tabu search heuristic algorithm. Iteration is used to search for a near-optimal solution. The performance of the tabu search heuristic and AMEXCLP are compared in terms of the realized expected coverage of EMS systems
Transportation and Production Lot-size for Sugarcane under Uncertainty of Machine Capacity
The integrated transportation and production lot size problems is important effect to total cost of operation system for sugar factories. In this research, we formulate a mathematic model that combines these two problems as two stage stochastic programming model. In the first stage, we determine the lot size of transportation problem and allocate a fixed number of vehicles to transport sugarcane to the mill factory. Moreover, we consider an uncertainty of machine (mill) capacities. After machine (mill) capacities realized, in the second stage we determine the production lot size and make decision to hold units of sugarcane in front of mills based on discrete random variables of machine (mill) capacities. We investigate the model using a small size problem. The results show that the optimal solutions try to choose closest fields and lower holding cost per unit (at fields) to transport sugarcane to mill factory. We show the results of comparison of our model and the worst case model (full capacity). The results show that our model provides better efficiency than the results of the worst case model
āļāļīāļāļāļīāļāļĨāļāļāļēāļāļāļĨāļ°āļāļāļāļĄāļ§āļĨāļĢāļ§āļĄāļāļĩāđāļŠāđāļāļāļĨāļāđāļāļāļģāļĨāļąāļāļĢāļąāļāđāļĢāļāļāļąāļāđāļĨāļ°āļāļēāļĢāļāļ°āļĨāļ°āļĨāļēāļĒāđāļĨāļŦāļ°āļŦāļāļąāļāļāļāļāļāļāļāļāļĢāļĩāļāļĄāļ§āļĨāđāļāļēāļāļŠāļĄāđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļInfluence of Aggregate Fineness Modulus on Compressive Strength and Heavy Metal Leaching of Lightweight Concrete Containing Recycled Melamine Waste
āļāļāļāļąāļāļĒāđāļ āļāļēāļāļ§āļīāļāļąāļĒāļāļĩāđāļĄāļĩāļ§āļąāļāļāļļāļāļĢāļ°āļŠāļāļāđāđāļāļ·āđāļāļĻāļķāļāļĐāļēāļāļīāļāļāļīāļāļĨāļāļāļēāļāļāļĨāļ°āđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļāļāđāļāļŠāļĄāļāļąāļāļīāđāļāļīāļāļāļĨāļāļāļāļāļāļāļāļĢāļĩāļāļĄāļ§āļĨāđāļāļēāđāļāļĨāļĨāļđāļĨāļēāļĢāđ āđāļāļĒāđāļāđāđāļāđāļāļ§āļąāļŠāļāļļāļĄāļ§āļĨāļĢāļ§āļĄāļĨāļ°āđāļāļĩāļĒāļāđāļāļāļēāļĢāđāļāļāļāļĩāđāļāļĢāļēāļĒāļĢāđāļāļĒāļĨāļ° 25 āđāļāļĒāļāđāļģāļŦāļāļąāļ āđāļāļĒāļĄāļĩāļāļąāļāļĢāļēāļŠāđāļ§āļāļ§āļąāļŠāļāļļāļāļĢāļ°āļŠāļēāļāļāđāļāļĄāļ§āļĨāļĢāļ§āļĄāļĨāļ°āđāļāļĩāļĒāļāđāļāđāļēāļāļąāļ 1.0 āđāļĨāļ° āļāļąāļāļĢāļēāļŠāđāļ§āļāļāđāļģāļāđāļāļ§āļąāļŠāļāļļāļāļĢāļ°āļŠāļēāļāđāļāđāļēāļāļąāļ 0.5 āđāļĨāļ°āļāļ§āļāļāļļāļĄāļāļ§āļēāļĄāļŦāļāļēāđāļāđāļāļāļāļāļāļāļāļāļĢāļĩāļāļŠāļ 1,300 āļāļīāđāļĨāļāļĢāļąāļĄ/āļĨāļđāļāļāļēāļĻāļāđāđāļĄāļāļĢ āļāļēāļĢāđāļāļāļāļĩāđāļāļĢāļēāļĒāļāđāļ§āļĒāđāļĻāļĐāđāļĄāļĨāļēāļĄāļĩāļāļāļĩāđāļĄāļĩāļāđāļēāđāļĄāļāļđāļĨāļąāļŠāļāļ§āļēāļĄāļĨāļ°āđāļāļĩāļĒāļāđāļāđāļēāļāļąāļ FM1.25 FM1.0 FM0.75 āđāļĨāļ° FM0.5āļāļēāļĢāļĻāļķāļāļĐāļēāļŠāļĄāļāļąāļāļīāļāđāļēāļ āđ āļāļāļāļāļēāļāļ§āļīāļāļąāļĒāļāļĢāļ°āļāļāļāļāđāļ§āļĒ āļāļģāļĨāļąāļāļĢāļąāļāđāļĢāļāļāļąāļ āļāļēāļĢāļāļđāļāļāļķāļĄāļāđāļģāđāļĨāļ°āļāļēāļĢāļāļ°āļĨāļ°āļĨāļēāļĒāđāļĨāļŦāļ°āļŦāļāļąāļ āļāļĨāļāļēāļĢāļĻāļķāļāļĐāļēāļāļāļ§āđāļē āļāļēāļĢāđāļāļāļāļĩāđāļāļĢāļēāļĒāļāđāļ§āļĒāđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļāļĢāđāļāļĒāļĨāļ° 25 āļŠāđāļāļāļĨāđāļŦāđāļāļģāļĨāļąāļāļĢāļąāļāđāļĢāļāļāļąāļāđāļĨāļ°āļāļēāļĢāļāļđāļāļāļķāļĄāļāđāļģāļāļāļāļāļāļāļāļĢāļĩāļāļĄāļ§āļĨāđāļāļēāđāļāļīāđāļĄāļāļķāđāļ āđāļāļĒāļāļĩāđāđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļāļāļĩāđāļĄāļĩāļāđāļēāđāļĄāļāļđāļĨāļąāļŠāļāļ§āļēāļĄāļĨāļ°āđāļāļĩāļĒāļāđāļāđāļē FM0.75 āđāļŠāļāļāļāđāļēāļāļģāļĨāļąāļāļĢāļąāļāđāļĢāļāļāļąāļāļŠāļđāļāļŠāļļāļ āļāļĩāļāļāļąāđāļāļāđāļēāļāļēāļĢāļāļđāļāļāļķāļĄāļāđāļģāļāļāļāļāļāļāļāļĢāļĩāļāļĄāļ§āļĨāđāļāļēāļĨāļāļĨāļāļāļēāļĄāļāđāļēāđāļĄāļāļđāļĨāļąāļŠāļāļ§āļēāļĄāļĨāļ°āđāļāļĩāļĒāļāļāļāļāđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļāļāļĩāđāđāļāļīāđāļĄāļāļķāđāļ āļŠāļģāļŦāļĢāļąāļāļāļēāļĢāļāļ°āļĨāļ°āļĨāļēāļĒāđāļĨāļŦāļ°āļŦāļāļąāļāļāļāļāđāļĻāļĐāļāļāļāđāļŠāļĩāļĒāđāļĄāļĨāļēāļĄāļĩāļāđāļāļāļāļāļāļĢāļĩāļāļĄāļ§āļĨāđāļāļēāđāļāļĨāļĨāļđāļĨāļēāļĢāđāļĄāļĩāļāđāļēāđāļĄāđāđāļāļīāļāļĄāļēāļāļĢāļāļēāļ U.S.EPA āđāļĨāļ°āļāļĢāļ°āļāļēāļĻāļāļĢāļ°āļāļĢāļ§āļāļāļļāļāļŠāļēāļŦāļāļĢāļĢāļĄ āļāļāļąāļāļāļĩāđ 6 āđāļĢāļ·āđāļāļ āļāļēāļĢāļāļģāļāļąāļāļŠāļīāđāļāļāļāļīāļāļđāļĨāļŦāļĢāļ·āļāļ§āļąāļŠāļāļļāļāļĩāđāđāļĄāđāđāļāđāđāļĨāđāļ§AbstractThis research aimed to investigate influence of aggregate fineness modulus on mechanical properties of cellular lightweight concrete containing melamine waste as fine aggregate. Melamine waste was used to partially replace sand at the rate of 25% by weight. The mixed ratio of cement: aggregate: water was set at 1:1:0.5 by weight. Density of fresh concrete was controlled at 1,300 kg/m3. The concrete specimens were varied by fineness modulus (FM) of the waste at FM1.25, FM1.0, FM0.75 and FM0.5. Compressive strength, water absorption and leaching test of heavy metal were investigated. The result was found that the melamine waste mixing yielded higher compressive strength and water absorption compared to reference lightweight concrete. The FM0.75 specimen resulted the highest compressive strength. It was also found that water absorption was slightly decrease with increasing fineness modulus of the waste. The leaching of heavy metals were determined by following the Toxicity Characteristic Leaching Procedure (TCLP). It was found that the concentration of As, Cd, and Pb were not exceed the limitation specified by the U.S.EPA and Ministry of Industry Announcement No. 6 (1997