A mixed-integer programming methodology to design tidal current farms integrating both cost and benefits: A case study in the Chacao Channel, Chile

2021 ◽  
Vol 294 ◽  
pp. 116980
Author(s):  
Maichel M. Aguayo ◽  
Pablo E. Fierro ◽  
Rodrigo A. De la Fuente ◽  
Ignacio A. Sepúlveda ◽  
Dante M. Figueroa
2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Li Luo ◽  
Jialing Li ◽  
Xueru Xu ◽  
Wenwu Shen ◽  
Lin Xiao

Beds are key, scarce medical resources in hospitals. The bed occupancy rate (BOR) amongst different departments within large tertiary hospitals is very imbalanced, a situation which has led to problems between the supply of and the demand for bed resources. This study aims to balance the utilization of existing beds in a large tertiary hospital in China. We developed a data-driven hybrid three-stage framework incorporating data analysis, simulation, and mixed integer programming to minimize the gaps in BOR among different departments. The first stage is to calculate the length of stay (LOS) and BOR of each department and identify the departments that need to be allocated beds. In the second stage, we used a fitted arrival distribution and median LOS as the input to a generic simulation model. In the third stage, we built a mixed integer programming model using the results obtained in the first two stages to generate the optimal bed allocation strategy for different departments. The value of the objective function, Z, represents the severity of the imbalance in BOR. Our case study demonstrated the effectiveness of the proposed data-driven hybrid three-stage framework. The results show that Z decreases from 0.7344 to 0.0409 after re-allocation, which means that the internal imbalance has eased. Our framework provides hospital bed policy makers with a feasible solution for bed allocation.


Author(s):  
Oguzhan Ahmet Arik

This paper proposes a mixed integer programming approach for seasonal anomalies in stock markets and presents a case study for the XU030 index in the stock market of Istanbul Stock Exchange (BIST). Stock markets are significant for economies of countries all over the world. Investors get economical wealth or lose some of their investment by selling and buying stocks. Therefore, buying and selling times of stocks are so important. This paper investigates a well-known effect called as ‘Sell in May and Go Away’ by proposing a MIP approach that searches best times for buying and selling of stocks in a year. Furthermore, this paper includes a numerical example of XU030 stock prices for the past 5 years and shows that most of the XU030 stocks have seasonal anomalies.Keywords: First keyword, second keyword, third keyword, forth keyword.


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