The objectives of this research were to find the distribution of food demand for laying hens and to find the optimum amount of that food production which had minimum cost. The data consisted of customer purchase orders for the food of laying hens price of food for laying hens cost per unit for the food inventory cost related to food of laying hens in which the food was out of stock such as fine overtime urgent purchase for material. They were collected in 2008-2009 form a factory in Nakhonratchasima province. The collected data were analized in order to explore the distribution of the monthly food demand for the laying hens and to see the rate of inventory per unit. The results were used in the stochastic linear programming model for aggregate planning in which the optimum production minimum cost could be obtained. Programming algorithm in MATLAB and tools in Linprog software were used to get the solution. The distribution of the food demand for laying hens and the random numbers were used in the model. The study found that the distribution of food demand for laying hens every month has normal distribution (January to December). The monthly average amount of production from January to December were 10936.94 12913.74 11898.12 13096 15443.26 14916.33 10322.64 10818.21 11393.11 11700.72 9706.05 and 11702.05 respectively. The minimum total cost average for 12months was Baht 62422386.98.

The objectives of the study were to find the arrival rate of applicants who applied to study at Rajamangala of Technology Pra Nakhon North Bangkok Campus the service rate of admission officers and to analyze queuing system in order to improve the admission system. The sample was 1722 technical students who applied to study in 10 divisions in 2007 and 2008. The plication date was collected every 10 minutes in each one-hour period from 09.00 am. to 16.00 pm. For 6 days. The study found that the distribution of the number of applicants was Poisson distribution. The highest arrival rate 1.29 student/min was at the second period and the lowest arrival rate 0.06 students/min was at the sixth period. The Distribution of service time at each station was exponential distribution. The highest service rate 0.67 min/student or 1.49 students/min was at the second station entering data into a computer. Queuing analysis in this study was series network. The analysis found that the highest expected number of applicants in the system 150 student/hour was at the first station in the second period and in the sixth period there was almost none. The highest expected number of applicants in the queuing system107.40 student/hour was at the first station in the second period The highest expected waiting time in the system.1.92 min/student and in the queuing system 1.37 min/student were at the first station. The probabilities of none of applicants in the system at the first the second and the third station in the sixth period were high 0.97 0.95 and 0.98 respectively. The proper value of the expected number of applicants in the system set in this study was not more than 60 student/hour and not less than 30 student/hour. The proper value of the waiting time in the system was not more than 1 min/student and not less than 0.5 min/student for stations for stations with more than one servers. The analysis found that at the first station one more server should be added in the second the third and the forth period and one less server should be reduced in the sixth period.