## 4 Proposed Solution
### Decision Support System  
In this section, the main features of the proposed DSS are discussed. Each doctor in the hospital department has his own list of patients and the waiting list of a team is composed by the merged list of doctors belonging to the team. Each team must schedule the patients from its waiting list during the time blocks previously booked by the head of the department. Thus, the main objective of the DSS is to help medical doctors perform a fast efficient and dynamic scheduling of the elective patients. The DSS uses as a core for the scheduling of patients the SHA approach presented in the previous subsection. However, other features are also included which enable (a) managing the medical teams and the OR time-table; (b) updating the waiting lists; (c) dynamic planning; and (d) improving the problem parameter by updating the surgeries duration. _Manage medical team and OR time-table._ Normally, the medical teams are composed of the same medical doctors. However, sometimes medical doctors could move from one team to another. The head of the department is responsible for updating the medical teams and including this information in the DSS. Moreover, the head of the department should define the ORs time-table in the DSS. The OR, the date, the starting time, and the ending time of each time block assigned to each team is the information that must be included in the DSS. _Updating the waiting list._ Generally, the new arrived patients are included at the end of the waiting list. However, depending on medical criteria, the surgeon could decide to advance the patient into a higher position in the waiting list. The DSS automatically orders the waiting list of patients. There are two parameters influencing directly the position of the patient in the waiting list. 1. The first parameter is related to the waiting time for surgery. A score \(S_{1}\) of 10 is given to the patient with the highest number of waiting days, while the newest patient has a score of 0. A proportional score between 10 and 0 is given to other patients. In the calculation of total score (denoted \(S_{T}\)), the score \(S_{1}\) has a weight of \(p\). 2. The second parameter has to do with the surgery priority. Although non-urgent surgeries are scheduled with the DSS, three levels of priorities 1, 2, and 3 are considered by doctors depending on the urgency. A corresponding score (\(S_{2}\)) of 0, 5, and 10 is associated respectively. The final score is obtained as follows:  
\[S_{T}=p\cdot S_{1}+S_{2} \tag{7}\]  
Finally, the patients are ordered according to their total score. The patient with the highest total score will be the first, while the patient with the lowest punctuation will be the last one. _Iterative planning._ The scheduler of each medical team performs the scheduling for the next \(|\mathcal{B}|\) time blocks (this is done by using the SHA). The secretary calls the patients scheduled and asks them for their availability on the scheduled date. The secretary gives back this information to the team scheduler who should schedule the empty gaps again. This process is repeated until the \(|\mathcal{B}|\) time blocks are completely scheduled with all patients confirmed. During the iterative scheduling, if a patient confirms the attendance, she/he is fixed in the corresponding time block. However, in the case that a patient cannot be contacted or she/he cannot be hospitalized, then the patient is not considered for the scheduling of the next \(|\mathcal{B}|\) time blocks. Thus, in the next iteration, the patients previously confirmed and the patients who cannot be hospitalized are not considered in the waiting list. The SHA schedules new patients in the gaps of the uncompleted time blocks. _Updating and customizing the average duration._ The average duration and standard deviation of each type of surgery should be computed using historical data from the hospital department. Considering two years, a sufficiently high number of surgeries of each type is obtained, and the average duration is representative.