In the present work, the proximate compositions, minerals and trace element contents of zander (S... more In the present work, the proximate compositions, minerals and trace element contents of zander (Sander lucioperca) caught from two lakes (Beyşehir Lake and Seyhan Dam Lake) of Turkey were compared. There were significant differences between moisture and lipid contents, ...
High demand but limited staffs within some services of a hospital require a proper scheduling of ... more High demand but limited staffs within some services of a hospital require a proper scheduling of staff and patients. In this study, a hierarchical mathematical model is proposed to generate weekly staff scheduling. Due to computational difficulty of this scheduling problem, the entire model is broken down into manageable three hierarchical stages: (1) selection of patients, (2) assignment of patients to the staff, (3) scheduling of patients throughout a day. The developed models were tested on the data collected in College of Medicine Research Hospital at Cukurova University using GAMS and MPL optimization packages. From the results of the case study, the presented hierarchical model provided a schedule that ensures to maximize the number of selected patients, to balance the workload of physiotherapist, and to minimize waiting time of patients in their treatment day.
Physical therapy, hemodialysis and radiation oncology departments in which patients go through le... more Physical therapy, hemodialysis and radiation oncology departments in which patients go through lengthy and periodic treatments need to utilize their limited and expensive equipment and human resources efficiently. In such departments, it is an important task to continue to treat current patients without any interruption along with incoming patients. In this study, a patient scheduling approach for a university radiation oncology department is introduced to minimize delays in treatments due to potential prolongations in treatments of current patients and to maintain efficient use of the daily treatment capacity. A simulation analysis of the scheduling approach is also conducted to assess its efficiency under different environmental conditions and to determine appropriate scheduling policy parameter values. Also, the simulation analysis of the suggested scheduling approach enables to determine appropriate scheduling parameters under given circumstances. Therefore, the system can perform more efficiently.
Influenza pandemics have occurred intermittently throughout the 20th century and killed millions ... more Influenza pandemics have occurred intermittently throughout the 20th century and killed millions of people worldwide. It is expected that influenza pandemics will continue to occur in the near future. Huge number of deaths and cases is the most troublesome aspect of the influenza pandemics, but the other important trouble is the economic impact of the influenza pandemics to the countries. In this study, we try to detect the cost of a possible influenza pandemic under different scenarios and attack rates. We include the vaccination and antiviral treatment cost for direct cost and we add the work absenteeism cost to the calculations for indirect cost of influenza pandemics. As a case study, we calculate the economic impact of pandemic influenza for Turkey under three different scenarios and three different attack rates. Our optimistic estimation shows that the economic impact of pandemic influenza will be between 1.364 billion dollars and 2.687 billions dollars to Turkish economy depending on the vaccination strategies.
International Journal of Production Research, 2010
In this paper, we deal with the problem of determining the optimal product mix and production qua... more In this paper, we deal with the problem of determining the optimal product mix and production quantities based on expanded ABC (activity-based costing) approach in the presence of obscure estimation of parameters for the capacities of the activities and the demands of each product. First, we give the mixed zero-one programming model such that the profit is maximised subject to capacities of activities and demand of products. Second, to handle vagueness of capacity and demand in real-life production systems in fuzzy environments, fuzzy programming is presented. We employ linear membership functions for the capacity of each activity and demand of each product. Using the data in the study of Kee (1995), we show the usefulness of the fuzzy model.
In the present work, the proximate compositions, minerals and trace element contents of zander (S... more In the present work, the proximate compositions, minerals and trace element contents of zander (Sander lucioperca) caught from two lakes (Beyşehir Lake and Seyhan Dam Lake) of Turkey were compared. There were significant differences between moisture and lipid contents, ...
High demand but limited staffs within some services of a hospital require a proper scheduling of ... more High demand but limited staffs within some services of a hospital require a proper scheduling of staff and patients. In this study, a hierarchical mathematical model is proposed to generate weekly staff scheduling. Due to computational difficulty of this scheduling problem, the entire model is broken down into manageable three hierarchical stages: (1) selection of patients, (2) assignment of patients to the staff, (3) scheduling of patients throughout a day. The developed models were tested on the data collected in College of Medicine Research Hospital at Cukurova University using GAMS and MPL optimization packages. From the results of the case study, the presented hierarchical model provided a schedule that ensures to maximize the number of selected patients, to balance the workload of physiotherapist, and to minimize waiting time of patients in their treatment day.
Physical therapy, hemodialysis and radiation oncology departments in which patients go through le... more Physical therapy, hemodialysis and radiation oncology departments in which patients go through lengthy and periodic treatments need to utilize their limited and expensive equipment and human resources efficiently. In such departments, it is an important task to continue to treat current patients without any interruption along with incoming patients. In this study, a patient scheduling approach for a university radiation oncology department is introduced to minimize delays in treatments due to potential prolongations in treatments of current patients and to maintain efficient use of the daily treatment capacity. A simulation analysis of the scheduling approach is also conducted to assess its efficiency under different environmental conditions and to determine appropriate scheduling policy parameter values. Also, the simulation analysis of the suggested scheduling approach enables to determine appropriate scheduling parameters under given circumstances. Therefore, the system can perform more efficiently.
Influenza pandemics have occurred intermittently throughout the 20th century and killed millions ... more Influenza pandemics have occurred intermittently throughout the 20th century and killed millions of people worldwide. It is expected that influenza pandemics will continue to occur in the near future. Huge number of deaths and cases is the most troublesome aspect of the influenza pandemics, but the other important trouble is the economic impact of the influenza pandemics to the countries. In this study, we try to detect the cost of a possible influenza pandemic under different scenarios and attack rates. We include the vaccination and antiviral treatment cost for direct cost and we add the work absenteeism cost to the calculations for indirect cost of influenza pandemics. As a case study, we calculate the economic impact of pandemic influenza for Turkey under three different scenarios and three different attack rates. Our optimistic estimation shows that the economic impact of pandemic influenza will be between 1.364 billion dollars and 2.687 billions dollars to Turkish economy depending on the vaccination strategies.
International Journal of Production Research, 2010
In this paper, we deal with the problem of determining the optimal product mix and production qua... more In this paper, we deal with the problem of determining the optimal product mix and production quantities based on expanded ABC (activity-based costing) approach in the presence of obscure estimation of parameters for the capacities of the activities and the demands of each product. First, we give the mixed zero-one programming model such that the profit is maximised subject to capacities of activities and demand of products. Second, to handle vagueness of capacity and demand in real-life production systems in fuzzy environments, fuzzy programming is presented. We employ linear membership functions for the capacity of each activity and demand of each product. Using the data in the study of Kee (1995), we show the usefulness of the fuzzy model.
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Papers by Esra Koyuncu