14  Extended Radiology Clinic

14.1 Data

Table 14.1: List of Global Variables
Name Description Initial Value
NextPatIdNum The Id number that will be assigned to the next patient 1
NextReceptionistIdNum The Id number that will be assigned to the next receptionist 1
NextCTMachineIdNum The Id number that will be assigned to the next CT Machine 1
\(P\) The set of all patients \(\emptyset\)
\(R\) The set of all receptionists \(\emptyset\)
\(C\) The set of all CT Machines \(\emptyset\)
Table 14.2: List of Data Modules
Name Source Model Type Input Output
PatientInterarrivalTime Problem Description Poisson Process Stochastic Mean interarrival time Sample from distribution
PatientPriority Problem Description Discrete Distribution Stochastic Priority Probabilities Sample from distribution
NumReceptionists Problem Description Constant Deterministic - Value
NumCTMachines Problem Description Constant Deterministic - Value
CheckInTime Problem Description Uniform Distribution Stochastic Min and max time Sample from distribution
ScanTime Problem Description Log-normal Distribution Stochastic Mean and std. dev. Sample from distribution

14.2 Components

Table 14.3: List of Entities
Entity Attributes
Patient ID
CurrentActivity
CurrentStart
Priority[0]
Receptionist ID
CurrentActivity
CurrentStart
CT Machine ID
CurrentActivity
CurrentStart
NeedMaintenance[0]
Table 14.4: List of Transitions
Participant Name From Event To Event
Patient P.1 Arrive(P) Wait for check in.Start
P.2 Wait for check in.End Check in.Start
P.3 Check in.End Wait for scan.Start
P.4 Wait for scan.End Scan.Start
P.5 Scan.End Leave(P)
P.6 Arrive(P) Wait for scan.Start
Receptionist R.1 Arrive(R) Wait for task(R).Start
R.2 Wait for task(R).End Check in.Start
R.3 Check in.End Wait for task(R).Start
R.4 Wait for task(R).End Leave(R)
CT Machine CT.1 Arrive(CT) Wait for task(CT).Start
CT.2 Wait for task(CT).End Scan.Start
CT.3 Scan.End Wait for task(CT).Start
CT.4 Wait for task(CT).End Leave(CT)
CT.5 Wait for task(CT).End Maintenance.Start
CT.6 Maintenance.End Wait for task(CT).Start
Table 14.5: Activities
Activity Participants Event Type State Change
Wait for Check In Patient (p) Start Scheduled 
TRIGGER OnStartWaitForCheckIn WITH p
End Controlled
Check In Patient (p), Receptionist (r) Start Controlled 
SCHEDULE Check In.End at TIME + CheckInTime()
End Scheduled 
START Wait for Scan WITH p # TRANSITION P.3
START Wait for Task (R) WITH r # TRANSITION R.3
Wait for Scan Patient (p) Start Scheduled 
TRIGGER OnStartWaitForScan WITH p
End Controlled
Scan Patient (p), CTMachine (c) Start Controlled 
SCHEDULE Scan.End at TIME + ScanTime()
End Scheduled 
START Leave (P) WITH p # TRANSITION P.5
START Wait for Task (CT) WITH c # TRANSITION CT.3
Wait for Task (R) Receptionist (r) Start Scheduled 
TRIGGER OnStartWaitForTaskR WITH r
End Controlled
Wait for Task (CT) CTMachine (c) Start Scheduled 
TRIGGER OnStartWaitForTaskCT WITH c
End Controlled
Maintenance CTMachine (c) Start Controlled 
SCHEDULE Maintenance.End at TIME + 30 minutes
End Scheduled 
c.NeedMaintenance = 0
START Wait for Task (CT) WITH c # TRANSITION CT.6
Table 14.6: Events
Event Participants Type State Change
Simulation Start - Scheduled 
SCHEDULE Arrival (R) at TIME
SCHEDULE Arrival (CT) at TIME
SCHEDULE Arrival (P) at TIME + PatientInterArrival()
Arrival (P) Patient (p) Scheduled 
p.ID = NextPatIDNum
p.Priority = PatientPriority()
NextPatIDNum = NextPatIDNum + 1
SCHEDULE Arrival (P) at TIME + PatientInterArrival()
IF p.Priority <= 2 THEN
  START Wait for Scan WITH p # TRANSITION P.6
ELSE
  START Wait for Check In WITH p # TRANSITION P.1
END IF
Leave (P) Patient (p) Scheduled 
Calculate statistics for p
Arrival (R) Receptionist (r) Scheduled 
r.ID = NextReceptionistIDNum
NextReceptionistIDNum = NextReceptionistIDNum + 1
IF NextReceptionistIDNum <= NumReceptionists THEN
    SCHEDULE Arrival (R) at TIME
END IF
START Wait for Task (R) WITH r # TRANSITION R.1
Leave (R) Receptionist (r) Scheduled 
Calculate statistics for r
Arrival (CT) CT Machine (c) Scheduled 
c.ID = NextCTMachineIDNum
NextCTMachineIDNum = NextCTMachineIDNum + 1
IF NextCTMachineIDNum <= NumCTMachines THEN
    SCHEDULE Arrival (CT) at TIME
END IF
START Wait for Task (CT) WITH c # TRANSITION CT.1
Leave (CT) CT Machine (c) Scheduled 
Calculate statistics for c
Require Maintenance CT Machine (c) Scheduled 
c.NeedMaintenance = 1
TRIGGER OnRequireMaintenance WITH c

14.3 Activity Diagrams

Figure 14.1: Patient Activity Diagram
Figure 14.2: Receptionist Activity Diagram
Figure 14.3: CT Activity Diagram

14.4 Logic

Table 14.7: OnStartWaitForCheckIn
Triggered by: Patient p 
receps = {r FOR r IN R IF r.State = "Wait for task (R)"}
IF receps IS NOT empty THEN 
    r_hat = argmin{r.CurrentStart FOR r IN receps}
    START Check In WITH p, r_hat # TRANSITIONS P.2, R.2
END IF
Table 14.8: OnStartWaitForScan
Triggered by: Patient p 
cts = {c FOR c IN C IF c.State = "Wait for task (C)"}
IF cts IS NOT empty THEN 
    c_hat = argmin{c.CurrentStart FOR c IN cts}
    START Scan WITH p, c_hat # TRANSITIONS P.4, CT.2
END IF
Table 14.9: OnStartWaitForTaskR
Triggered by: Receptionist r 
patients = {p FOR p IN P IF p.State = "Wait for Check In"}
IF patients IS NOT empty THEN 
    p_hat = argmin{p.CurrentStart FOR p IN patients}
    START Check In WITH p_hat, r # TRANSITIONS P.2, R.2
END IF
Table 14.10: OnStartWaitForTaskCT
Triggered by: CTMachine c 
patients = {p FOR p IN P IF p.State = "Wait for Scan"}
IF c.NeedMaintenance = 1 THEN
  START Maintenance WITH c # TRANSITION CT.5
IF patients IS NOT empty THEN
    top_priority = max{p.Priority FOR p in patients}
    top_patients = {p FOR p IN patients IF p.Priority = top_priority}
    p_hat = argmin{p.CurrentStart FOR p IN top_patients}
    START Scan WITH p_hat, c # TRANSITIONS P.4, CT.2
END IF
Table 14.11: OnCTMachineArrive
Triggered by: CT Machine c 
SCHEDULE Require Maintenance WITH c at TIME + 8 hours
Table 14.12: OnRequireMaintenance
Triggered by: CT Machine c 
SCHEDULE Require Maintenance WITH c at TIME + 8 hours
IF c.CurrentActivity = "Wait for task (C)" THEN
  START Maintenance WITH c # TRANSITION CT.5
END IF