Haneul Ko

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1. Introduction In the flourishing cloud industry [1], there are two kinds of players: cloud operators (i.e., cloud providers) and service providers (i.e., cloud consumers). The cloud operators have three primary deployment models: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS) [2,3]. Specifically, IaaS provides on-demand infrastructure resources to consumers via the cloud, such as computing, storage, networking, and virtualization.

1. Introduction In the last few years, the Internet of Things (IoT) has been rapidly growing across the world, which enables users to experience various environmental monitoring services [1]. In these services, the monitoring server periodically updates its service (e.g., a traffic and air quality monitoring map) by analyzing the received fresh data (e.g., the air quality and traffic intensity on each location) from sensor nodes (SNs) during the service update cycle [1,2,3].