OR-NET 2017

Papers presented at National Operations Research Network Conference (OR-NET) 2017, March 2017, Nakhon Ratchasima, Thailand.

Assessing Agricultural Supply Chain Flexibility by Stochastic Programming: A Case Study of Cassava in Thailand
ปารียา ศิริวัฒนพันธ์ & สราวุธ จันทร์สุวรรณ

The agricultural supply chain and logistics has been more focused by the government. The capacity building on agricultural supply chain is also integrated into the national strategies. It extensively emphasizes on the enhancement of the efficiency and the competitiveness of agricultural products from farm (farmers) to forks (midstream or downstream producers or consumers) by providing ways to improve the overall management in the supply chain. The traditional performance indicators usually consider the factors such as cost, lead time, and reliability. However, the supply chain flexibility which is defined as the ability of all players in the supply chain can accommodate the additional demand which possibly varied from reasons such as pricing change or subsidy from government. The objective of this study is to develop a mathematical programming model to
assess the supply chain flexibility. The case study of cassava and starch producers in Thailand is adopted to demonstrate the applicability of the model. In this study, the proposed model is stochastic programming with two stage approach of profit maximization model is used to assess the capacity flexibility. The first stage is to assess the base pattern of demand flow along the supply chain networks. The second stage is to evaluate the reserve capacity using the pattern obtained from the first stage. The models could be further used to identify the bottlenecks and also be used to evaluate the effectiveness of the policy and budget allocation for improving the cassava supply chain.
Keywords: supply chain flexibility, agricultural supply chain, cassava, stochastic programming


A hybrid saving-sweep algorithm for vehicle routing problem model: case study of automobile part manufacturer in Thailand
ลักษณ์พิเชษฐ คชวัตร และ สราวุธ จันทร์สุวรรณ
The objective of this study is to develop an alternative algorithm for vehicle routing problem (VRP) for managing the automotive stamping part transportation. This study explores the heuristics algorithms for solving the VRP model including saving, sweep, sweep skipping and applies for the real case study. An alternative hybrid saving-sweep algorithm is introduced to overcome the disadvantages of saving and sweep algorithm. As expected, the saving algorithm performs better than sweep algorithm but the derived VRP plans are not practical which may be ignored by the drivers. However, the results obtained from hybrid saving-sweep algorithm indicate the more practical advantage as it can better reflect the VRP plan for picking the automotive parts from several suppliers.
Keywords: VRP, Hybrid Saving-Sweep Algorithm, Sweep Algorithm , Saving Algorithm, Heuristics


Room allotment and overbooking: Case Study for Hotel
ณัฐ พงศ์ไทย  & กาญจ์นภา อมรัชกุล
In this article, we determine a suitable allotment for hotel reservations in order to maximize the expected total profit.
Hotel customers can be divided into three groups, namely 1) a contracted agency with allotment, 2) an agency without allotment,
and 3) an online travel agency. The three groups face different demands, and they are charged based on different prices. On
average, the last group is charged with the highest price, whereas the first group with the lowest price. After the suitable allotment
for each group is determined, an overbooking limit is calculated in order to minimize the expected total cost. In order to find an
optimal overbooking limit, we assume that demand follows a Poisson distribution with a different mean for each group. From our
numerical result, if our policy had been implemented in 2015, the expected profit would have been increased by 10,782,604.50
THB, which would have been equivalent to 5.99% profit increase, compared to the policy the hotel actually implemented. Also,
the compensation from hotel denied services would have been reduced by 7,920,000 THB annually.
Keywords: Room allotment, booking limit, protection level, overbooking