Browsing by Author "Santithammarak, Vanlapha"
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Item Model for improving the logistics processes for propane delivery(2008-08) Santithammarak, Vanlapha; Smith, Milton L.; Simonton, James L.; Kobza, John E.The scheduling problem of service times and the method to provide service to customers by minimizing time, cost, and distance are important for service providers and are challenging research topics. This research problem concerns the scheduling of the delivery of propane to a large number of customers in a rural area. Prediction of customer demands must be done before service times are scheduled. In this research, there are two types of customer demands; one is regular customer demands and the other is call-in customer demands. This problem is similar to a situation having regular tasks and emergency tasks that come up to interrupt the regular tasks. The regular customer demands are scheduled and the regular service is assumed to be the routine every day. The data collection of regular customer demands are observed from historical demands of regular customers and separated by season as summer and winter. Afterwards, the proper mean (ë) number of call-in customers per day is calculated, and it is established that the Poisson distribution applies. Subsequently the call-in services are scheduled after these customers call for service. The challenge of this research is that each customer service time is scheduled in the time limit per day. In addition, the locations of regular customers are investigated before grouping regular customers together to provide service on the same day. This research focuses on the method to integrate the schedule containing regular customers with the call-in customers in each day.Item Vulnerability of electric power systems to terrorist attack(2011-12) Santithammarak, Vanlapha; Smith, Milton L.; Farias, Ismael R. d.; Simonton, James L.; Kobaz, John E.; Marcy, William M.Terrorist attacks designed to weaken the economy of the United States are of increasing concern since September 11, 2001. Electrical power generation and distribution systems should be regarded as likely targets of terrorists because electrical energy is essential to most economic activities. The objective of this research study is to investigate the possible methods of a successful terrorist attack in the electrical infrastructure and to reduce vulnerability in electric power system by evaluating the performance of protection systems and selecting the best effective protection method. This study might help to increase the protection measures and to decrease the probability of terrorist attack on the electric power system. The location and time of terrorist attack will not be forecasted; rather it is assumed that terrorists will want to attack the assets. Those assets can be generating stations, substations, and transmission lines but substations are the most likely target from terrorists’ view because of asset value, remoteness and being unmanned. There are many weapons that terrorists could use, but explosives or high powered rifles are the weapons considered in this research. One large substation will be used in this study as an example. This substation is very a large and damage to it may cause blackout in the region it serves. The protection approaches for this substation can be applied to other substations and generating plants. This research examines criteria for protection approaches and methods to evaluate effectiveness of protection systems.