An actuator is a device responsible for moving or controlling other mechanisms, systems or equipment. Actuators can control parameters such as lights, temperature, and humidity in order to improve the level of comfort of public buildings and to reduce the costs of heating or cooling (Zanella et al. 2014).


A digital tool, monitoring application, application module, or another deployable component, designed to perform a group of coordinated functions, tasks, or activities for the benefit of the city users (Hefnawy et al. 2016).

Application back-end:

The back-end includes application components to support the business processes that do not directly involve customer interactions. The main objective of the back-end is to process the information efficiently (Kuk & Janssen 2011).

Application front-end:

The front-end includes application components to support the business processes that are used to interact directly with citizens and/or businesses. The main objective of the front-end is to ensure demand-driven service delivery (Kuk & Janssen 2011).

City Service:

A city service is a service offered to the citizens by the city government (e.g. air-quality service, transport service, health service, etc.) (Anon 2014)(Nesi et al. 2016)

Cloud storage services:

Cloud storage is a cloud computing model in which data is stored on remote servers accessed from the internet using virtualization techniques. Cloud computing offers large-scale data storage and computational services to smart cities (Mohamed et al. 2017).

Data Entity:

A data entity is an encapsulation of data that is related to specific real-world things (e.g. sensors, mobile phones, city zones, etc.) (Cox et al. 2016)


A document provides information generated by public agencies or private sector in accordance with data protection regulations for personal and confidential information (Anthopoulos & Tsoukalas 2006).


A smart city domain such as education, health, mobility, living, environment, etc (Gaur et al. 2015)(Neirotti et al. 2014).


A gateway is a computer that links the smart devices at the edges of the network to a core network infrastructure. Gateways allow the communication and connectivity between the devices and the network and the management of these devices (Sánchez et al. 2013).


Goals represent what multiple stakeholders of a city aim to achieve as a common outcome; e.g., reducing energy consumption and CO2 emissions. (McGinley & Nakata 2015)


The information represents the data processed, interpreted, organized and structured to be meaningful to the users. The information provides a context for the data. In a Smart City, devices, services, and applications are connected through the Internet to collect and produce useful information (Jin et al. 2014).


A place where the activities of the city are carried out (e.g. roads, bridges, airports, tunnels, buildings, etc.) (Bellini et al. 2014)(Gil-Garcia et al. 2015).


A middleware is a software that offers common services for applications and easy application development by integrating heterogeneous computing and communications devices. A middleware supports the interoperability of diverse applications and services running on such devices (Razzaque et al. 2016).


A notification describes a city event (e.g., earth motion detection) produced by sensors according to the requirements of the stakeholders. Notifications are published through the enabled client applications (Filipponi et al. 2010).

Public and Private Data:

The data of smart cities contain several types of data entities that provide a common operating framework of the city. A data entity is an encapsulation of data that is related to specific real-world things (e.g. sensors, mobile phones, city zones, etc.), (Cox et al. 2016).


A sensor is a device that detects events or changes in the environment and sends the information to other electronics, frequently a computer processor (e.g. gateway). Sensors impact the quality of life for the citizens in terms of their transportation, activities and wellbeing (Samaras et al. 2013).

Software Modules:

A module is part of a program or a software component that contains one or more routines in order to provide the data requested by the user in a transparent means (Massana et al. 2017).

Software Service:

A software functionality or a set of software functionalities which provide useful information to the citizens (e.g., number of people in different places of interest, location of nearby hospitals, amount of Carbon dioxide CO2 in the street, etc) (Santana et al. 2016).


A stakeholder is a person, group or organization with an interest or concern in the operations of the city and its agencies or institutions (e.g. city authorities, citizens, communities, retailers, etc.) (Comerio et al. 2013) (Lnenicka et al. 2017)



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