Model Documentation

Architecture *

The model uses a discrete-event simulation pattern built on Repast Simphony’s scheduling system.

Core Components *

builders/Builder.java     Entry point, parameter configuration, HCW creation
containers/Hospital.java  Patient/bed management, data collection
agents/                   Patient, Nurse, Doctor, Therapist classes
processes/                Admission, Discharge, Transfer, PatientVisit

Agent Types *

Patients move through the hospital via ADT processes. Each patient has:

  • Admission time and location (ICU or ward)
  • Scheduled discharge time (Gamma-distributed LOS)
  • MRSA colonization/infection status

Healthcare Workers include nurses, physicians, and therapists (RT, PT, OT). HCWs are assigned to either ICU or ward and visit patients stochastically based on Gamma-distributed inter-visit times.

Patient Flow *

Admission → [ICU or Ward] → Transfer (if ICU) → Discharge
              ↓                    ↓
         HCW Visits           HCW Visits
  1. Admission: Exponential inter-arrival times; patients assigned to ICU with probability icuAdmitProbability
  2. Length of Stay: Log-normal distributed, parameterized separately for ICU and ward
  3. Transfer: ICU patients may transfer to ward based on Gamma-distributed timing
  4. Discharge: Patient removed, DischargedPatient record created

Disease Transmission *

MRSA spreads via HCW-mediated contact:

  1. Importation: Patients may arrive colonized (probability admitImportationInfectionProbability)
  2. Transmission: During visits, MRSA can transfer:
    • Colonized patient → HCW hands (if no hand hygiene)
    • Contaminated HCW → susceptible patient
  3. Interventions: Hand hygiene before/after visits and PPE for contact precautions reduce transmission probability

Transmission Probability *

Per-visit transmission probability depends on:

  • Patient colonization status
  • HCW hand contamination status
  • Hand hygiene adherence (pre- and post-visit)
  • PPE adherence if patient on contact precautions
  • Hand hygiene efficacy (hhEfficacy)

Scheduling *

The model uses Repast’s ISchedule with:

  • Continuous time: Processes self-schedule using distribution samples
  • Daily operations (@ScheduledMethod(interval=1)): Reset therapy needs
  • Per-shift operations (interval=0.5): Reassign nurse-patient assignments
  • End of run (start=365): Write output files