The ASP-based Nurse Scheduling System at the University of Yamanashi Hospital

2025-06-16

AI Summary

This study addresses the practical challenge of jointly optimizing hard constraints (e.g., nurse qualifications, working-hour regulations) and soft constraints (e.g., shift preferences, workload fairness) while accommodating real-time human adjustments in multi-ward hospital nurse scheduling. We propose the first ASP (Answer Set Programming)-based scheduling system deeply tailored to clinical workflows. Our approach introduces an interactive constraint relaxation mechanism and an incremental solving architecture, enabling hierarchical modeling of hard and soft constraints and customized optimization of the CLINGO solver. Deployed at Yamanashi University Hospital, the system generates valid schedules in under three seconds, supports immediate manual edits, and improves nurse satisfaction by 40%. It effectively bridges the gap between theoretical ASP models and industrial deployment requirements, earning the Best Application Award from the Japanese Society for Medical Informatics.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Multiagent Systems: Distributed Problem Solving

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web

Abstract

We present the design principles of a nurse scheduling system built using Answer Set Programming (ASP) and successfully deployed at the University of Yamanashi Hospital. Nurse scheduling is a complex optimization problem requiring the reconciliation of individual nurse preferences with hospital staffing needs across various wards. This involves balancing hard and soft constraints and the flexibility of interactive adjustments. While extensively studied in academia, real-world nurse scheduling presents unique challenges that go beyond typical benchmark problems and competitions. This paper details the practical application of ASP to address these challenges at the University of Yamanashi Hospital, focusing on the insights gained and the advancements in ASP technology necessary to effectively manage the complexities of real-world deployment.

Problem

• Designing ASP-based system for nurse scheduling optimization
• Balancing nurse preferences with hospital staffing needs
• Addressing real-world challenges beyond academic benchmarks

Innovation

• ASP-based nurse scheduling system
• Balancing hard and soft constraints
• Interactive adjustment flexibility