Performance evaluation of cloud-based publish/subscribe systems for the Internet of things : doctoral thesis - Antonić, Aleksandar; Podnar Žarko, Ivana (Zagreb : A. Antonić; Faculty of electrical engineering and computing, 2021)
The Internet of Things (IoT) is a concept that connects things and objects from the environment and everyday life into a global network and serves as a foundation for development of advanced, self-configuring services adapted to the user context. The thesis presents the CUPUS middleware, an open-source publish/subscribe solution for IoT environment. The CUPUS middleware is compared with other publish/subscribe solutions, and the thesis provides classification of publish/subscribe solutions reported in the literature in seven groups based on their capabilities and characteristics. The thesis proposes analytical modelling of aggregate input load of IoT services and modelling of processing times of publish/subscribe components using well-known distributions. Finally, a process to create a Queueing Theory model of publish/subscribe solution is proposed and demonstrated on the CUPUS middleware. The output of the model that estimates the processing time at individual component or in the system overall is in accordance with the results that were collected during the experimental evaluation of the middleware.

The scientific contribution of the proposed research in the doctoral thesis is the following:
- a taxonomy of cloud-based publish/subscribe systems for continuous processing of sensor data streams in the area of the IoT;
- analytical performance model of cloud-based publish/subscribe systems based on queueing theory;
- verification method of the analytical performance model which compares modelling results with the observed publish/subscribe system.
Internet stvari (IoT) je koncept koji povezuje stvari i objekte iz okoliša i svakodnevnog života u globalnu mrežu te omogućuje izgradnju naprednih, samo-konfigurirajućih usluga prilagođenih kontekstu korisnika. Rad predstavlja međuopremu CUPUS, rješenje otvorenog koda sustava objavi-pretplati za IoT. Međuoprema CUPUS uspoređuje se s drugim sustavima objavi-pretplati, a disertacija predstavlja klasifikaciju sustava objavi-pretplati iz literature u sedam skupina na temelju njihovih mogućnosti i karakteristika. U radu je predložen analitički model za određivanje ukupnog ulaznog opterećenja IoT usluga i modeliranje vremena obrade komponenti sustava objavi-pretplati pomoću poznatih distribucija. Predložen je proces stvaranja analitičkog modela temeljen na teoriji repova čekanja za sustave objavi-pretplati, a demonstriran je na međuopremi CUPUS. Rezultati analitičkih modela koji procjenjuju vrijeme obrade na pojedinačnoj komponenti ili u cjelokupnom sustavu u skladu su s rezultatima prikupljenim tijekom eksperimentalne evaluacije.
U radu su ostvareni sljedeći doprinosi:
- taksonomija sustava objavi-pretplati namijenjenih računalnom oblaku za kontinuiranu obradu tokova senzorskih podataka u području Interneta stvari;
- analitički model performanci sustava objavi-pretplati namijenjenih računalnom oblaku koji se temelji na teoriji repova čekanja i posluživanja;
- metoda verifikacije analitičkog modela performanci koja uspoređuje rezultate modeliranja s opaženim performancama sustava objavi-pretplati.
Bibliografija str. 193-214.