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Modeling ambulance dispatching rules for EMS-systems
KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
2016 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesisAlternative title
Modellering av dirigeringsstrategier för EMS-system (Swedish)
Abstract [en]

This thesis presents a study on efficient dispatching rules in ambulance dispatching. By efficient dispatching rules, we mean such dispatching rules that lower response times for priority 1 calls while keeping response times for priority 2 calls at an adequate level. A Markov process and a simulation model were developed in order to evaluate the performance of several existing and newly designed dispatching rules. On four different response areas, five different dispatching rules were tested and their performances were compared. Particular focus was put upon the dispatch rule currently used by the Swedish emergency service provider SOS Alarm; the Closest rule. Our findings indicate that the four priority-based dispatching rules all outperform the Closest rule in decreasing the mean response time for calls of priority degree 1. Furthermore, implementing restrictions on the travel time for priority 2 calls was proven an efficient way to control the trade-off between the mean response time of priority 1 and 2 calls. The conclusion was drawn that the possibilities for more efficient ambulance dispatching are many and that SOS Alarm should consider implementing priority-based dispatching rules, alike the ones presented in this thesis, in their dispatching process. A study of the ambulance operator and controller profession, and the operator’s and controller’s interplay with the decision support system used by SOS Alarm in the ambulance dispatching process, was conducted in parallel. The properties of the interaction dynamics between operator and automation and the dangers linked to it were mapped out, described and analyzed.

Abstract [sv]

Denna kandidatexamensuppsats behandlar effektiva dirigeringsstrategier inom ambulansdirigering. Effektiva dirigeringsstrategier åsyftar dirigeringsstrategier som lyckas sänka svarstiden för inkommande prioritet 1-samtal, samtidigt som svarstiden för prioritet 2-samtal hålls på en tillfredsställande nivå. I syfte att utvärdera olika dirigeringsstrategier utvecklades både en Markovsk modell och en simuleringsmodell. På fyra olika geografiska områden testades och jämfördes. Fem olika dirigeringsstrategier, varav två existerande och tre nyutvecklade. Särskilt fokus riktades mot Closest rule, vilket är den dirigeringsstrategi som används i SOS Alarms verksamhet idag. Från resultaten kunde utläsas att de prioritets-baserade dirigeringsstrategierna resulterade i en lägre genomsnittlig svarstid för prioritet 1-fall än Closest rule. Dessutom konstaterades det att en begränsning av svarstiderna för prioritet 2-samtal var ett effektivt sätt att kontrollera balansen mellan de genomsnittliga svarstiderna för samtal av prioritet 1, respektive 2. Slutsatsen drogs att möjligheterna för att utveckla nya effektiva dirigeringsstrategier är många och att SOS Alarm bör överväga att implementera prioritetsbaserade dirigeringsstrategier likt dem som presenterats i denna uppsats. Parallellt studerades ambulansoperatörens och -dirigentens yrkeskunnande, samt operatörens och dirigentens samspel med det beslutsstödssystem som används i SOS Alarms dirigeringsverksamhet. Interaktionen mellan operatör och automatisering samt de relaterade riskerna kartlades, beskrevs och analyserades.

Place, publisher, year, edition, pages
TRITA-MAT-K, 2016:35
Keyword [en]
Ambulance dispatching, Ambulance logistics, Emergency medical services, Priority-based dispatching rules, Markov process, Professional competencies
Keyword [sv]
Ambulansdirigering, Ambulanslogistik, Prehospital sjukvård, Prioritets-baserade dirigeringsstrategier, Markovprocess, Yrkeskunnande
National Category
URN: urn:nbn:se:kth:diva-189023OAI: diva2:942703
Subject / course
Optimization and Systems Theory
Educational program
Master of Science in Engineering - Industrial Engineering and Management
Available from: 2016-06-26 Created: 2016-06-26 Last updated: 2016-07-12Bibliographically approved

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