Abstract
Cities are multifaceted and highly complex interconnected systems of people, objects, and machines, bringing endless design, construction, and operational challenges. To be intelligent, the parts of a city and the relationships and connectivity among them need to be smart. Much work has been done on models and reference architectures for intelligent cities to achieve the smart integration of city domains. Nevertheless, a universally complete smart city reference architecture does not exist. This chapter aims to discuss accepted dimensions of an intelligent city and the best arrangement for connectivity of them. Through literature review of relevant studies from academia, international organizations, and standards organizations that analysed contributions ranging from enunciations of smart cities' relevant dimensions, conceptual models, reference architectures, and urban platforms, this chapter aggregates the dimensions to align the reference model for intelligent cities that reflects the importance of the core relevant dimensions.
TopIntroduction
Intelligent Cities, also known as Smart Cities, are multidimensional and highly complex interconnected systems of people, software, machines, smart objects, and data. Systems with this high level of complexity and connectivity have been studied from diverse perspectives and are referred to by numerous different designations e.g. system of systems (SoS) (Maier, 1998); cyber-physical systems (Lee, 2008), (Griffor, Greer, Wollman, & Burns, 2017); cyber-physical-social systems (Wang, 2010); socio-technical systems (Fischer & Herrmann, 2011); and multi-scale systems (Kevrekidis, Gear, & Hummer, 2004).
Besides intelligent cities have attracted extensive and emerging interest from both academia and industry with an increasing number of international examples and use cases emerging from all over the world. There is no unique and consensual definition for what constitutes a smart city, though the most common characteristic among all definitions is the strong recurrence to Information and Communications Technology (ICT), including latest tecknological paradigms such as Cloud Computing, Internet of Things (IoT), Indjustrial IoT, connectivity protocols, and Social Media offerings.
These emerging complex and interactive connected systems, based on latest technologies, that constitute different aspects and components of the cities ecosystem, bring new design, construction, and operational challenges. A significant challenge of these types of evolving projects, related to the improvement of the quality of life for citizens, is how to manage complexity, including interoperability, in an SoS with many continuously changing components.
If there is still no single definition of what an intelligent (or smart) city is, even less is there a unified reference model, a description of the basic arrangement and connectivity of the parts of the city. There still is missing a complete broader overview and skeleton of the interlinked items, which might constitute an all-encompassing architecture that provides guidance, design patterns, common vocabulary, and enables an end-to-end information flow, lowering barriers to interoperability; and thereby enabling stakeholders of smart city projects to perform more and faster implementations.
The infrastructures of a city were often developed and provided through stand-alone (silo-vertical) systems. Now, however, enhanced smart services interworking across domains, in combination with data analytics, is required to leverage the opportunities of digitalization. Current architectural standardization efforts have not yet converged, exhibiting a lack of consensus on a common language/taxonomy and architectural principles. Thus, the interworking across multiple urban infrastructures requires a coordinated approach avoiding that the different management systems are all dealing independently.
Dedicated domain-specific systems are still required to operate the related urban infrastructures, thus such urban systems need to follow an open design approach, e.g. with open interfaces, supporting open standards for exchanging urban data and supporting new urban services extending the scope of the Intelligent City services over time by increased use of digitalization. To provide this SoS like approach, requires interoperability of systems at all levels as a core principle.
A reference architecture provides the common framework around which more detailed discussions can centre. By staying at a higher level of abstraction, it enables the identification and comprehension of the most important issues and patterns across its applications in many different use cases. An intelligent city reference architecture will contribute to alleviate real-world deployment of intelligent cities, bringing advantages like interoperability assurance, integration facilitation, reuse, risk reduction, better quality, and knowledge transfer.
As said before, there is no single definition for smart cities, neither is there a single global and unified reference model, nor a reference architecture that permeates the entire operation of a smart city. However, several models for understanding and conceptualizing smart cities have been developed, which aim to define their definition, scope, objectives, benefits, and architectures.
Key Terms in this Chapter
Framework: This refers to a structure for content or process that represents a broad overview, skeleton, or outline, of interlinked items which supports a particular approach to a specific objective, and serves as a guide that can be modified as required by adding or deleting items.
Reference Model: A reference model describes both types of entities or domains and their relationships, including a description of the problem that it solves, and the concerns of the stakeholders who need the problem to be solved. A reference model is intended to promote understanding of a class of problems, not to provide specific solutions for those problems, being technology agnostic. In addition, a reference model provides a more complete view of, or templates for, the overall setup and its domain implementation.
Design Principle: Design principles provide a systemization of knowledge describing the constituents of a phenomenon. They support practitioners in developing appropriate solutions and from an academic perspective. These principles form the foundation of a design theory.
Concern: Concerns refer to an interest in a system relevant to one or more of its stakeholders. They may relate to the system’s functioning, development, or operation, including considerations related to non-functional requirements.
Reference Architecture: A reference architecture is an architecture where the structures and respective elements and relations provide templates for concrete architectures in a particular domain or family of systems. It provides a template solution for an architecture, delivering a common vocabulary with which to discuss implementations, and stressing commonality.
Urban Platform: This refers to a system that facilitates the exploitation of city data and intelligent monitoring and control of the cities infrastructures and assets, and that enables new and improved services for public and private ends and stakeholders. Desirably should utilise open standards and interfaces to guarantee compatibility and interoperability with other systems.
Conceptual Model: It refers to a generic, abstract and simple structure and definitions for describing the concepts of, and the relationships among, the entities within systems. In order to achieve this goal, it is important to clarify the fundamentals of the systems by asking for the overall model of entities and their relationships, the key concepts in a typical system, and who and where are the actors.
Requirement: In systems engineering, a requirement can be defined as something that needs to be conceived. It refers to the properties that the systems (under consideration) shall possess when designed and built, and express the users’ necessities and restrictions that are placed on the system and that must be considered during the development.
Architecture: The architecture of a system is a metaphor analogous to the architecture of a building, in the sense that it functions as a blueprint for the system and the development. This refers to a description of the arrangement and connectivity of the parts of a system, their relationships to one another and to the environment and the principles guiding its design and evolution.
Aspect: It refers to the high-level grouping of conceptually equivalent or related concerns that manifest interest in a system relevant to at least one of its stakeholders.