3.1.1. Technologies and tools for citywide geodata collection and management
Geodata (also known as geospatial data) is the spatially referenced data or data that has a geographic or spatial component [
24]. Geo-spatial data encompasses a broad spectrum of data sets and formats, and its versatility makes it applicable to solving a wide range of tasks associated with all phases of disaster resilience management [
25]. Citywide geodata collection and management is vital for disaster resilience as it provides cities with valuable insights so that the cities could better prepare for, respond to, and recover from disasters. Below is a list of identified tools and technologies that are important for citywide geodata collection and management.
Cloud computing is a computing technique that delivers various IT services with low-cost computing units connected by IP networks so that users from anywhere with an internet connection can access these IT services on-demand without needing to install any hardware or software on their local devices [
26,
27]. As the cloud offers virtually unlimited resources by means of computing power and storage, geodata -and Web-GIS applications are naturally taking advantage of cloud computing technologies [
28]. While cloud computing provides the infrastructure and platform to enable the digital technologies that Smart Cities employ to improve the quality of life of their citizens, increase efficiency and enhance sustainability [
29]; its potential to revolutionise the Smart City landscape helps make them disaster resilient.
During disaster situations, cloud computing enables the data and computation (software being used, algorithms, etc.) to be saved (time snapshot) and relocated to another (safer) physical location swiftly, this includes system backup [
30]. Large amounts of disaster related data collected from different sources like sensors, satellite imagery, social media, etc. can be stored and analysed and that helps cities to preidentified hazards and disaster risks and prepare [
31]. Cloud computing also offers concurrent access to the cloud which may help increase community engagement [
32]. Most importantly, cloud computing serves as an underlying infrastructure that provides the on-demand computing resources to meet dynamic computing requirements of real-time disaster/hazard analysis, emergency response and disaster coordination [
33]. Cloud Computing also offers a finer solution for disaster modelling and simulation [
34] and eventually helps Smart City infrastructure to identify existing vulnerabilities so that resilient infrastructure could be better designed/ improved. However, during the actual disaster scenarios where power, electricity, and communication infrastructure are broken down, the use of cloud services becomes a challenge [
31]. To overcome the challenges to use cloud services during disasters, the involvement of evolving disruptive technologies including fog and edge computing, and network work is recommended [
10,
31]. According to the researchers, Ujjwal, Saurabh, James, Jagannath and Nicholas [
31] these technologies act as a transitional data delay for cloud’s further assessment. Further, some studies have also looked at the resiliency techniques in cloud computing infrastructures and applications [
35].
The Internet of Things (IoT) is a term used to describe the connection of physical objects like mobile devices, sensors, buildings, vehicles, etc. to the Internet, allowing them to collect and exchange data with each other [
36]. Some of the IoT implementations feature smart roads, smart grids, smart parking, tank levels, traffic congestion, smartphone detection, radiation levels, smart product management, landslide and avalanche prevention, snow level monitoring, etc. [
37]. With the development of Smart City solutions that employ IoT, the world was offered with more factual knowledge about urban systems with high spatial and temporal resolutions [
38]. The density and coverage of IoT devices and relatively low energy consumption allow large self-organising networks in emergency communication for longer periods [
39]. IoT-enabled disaster management systems that incorporate evolving data analytics and artificial intelligence tool can be used as early warning mechanisms and in finding the victim and possible rescue operations [
40].
Literature refers to Bigdata using 2 different defining characteristics 1) the massiveness of data and 2) complementing techniques and evolving technologies that are vital for the effective processing and conducting insightful analysis of massive volumes of data in a way that their hidden values can be discovered [
41,
42]. With advanced Big Data Analytics large disaster related datasets from multiple sources can be examined in real time during all the phases of disaster management (including preparedness, mitigation, response, and recovery) to extract valuable information that can help make informed decisions during the resilience journey [
41]. Multidimensional big data analytics including descriptive, prescriptive, predictive, and discursive analytics helps create and enhance resilience in the aforementioned phases of disaster management, especially in restoring normal life following a disaster [
43]. According to the authors Sarker, Peng, Yiran and Shouse [
43], descriptive analytics deals with the description of the status, condition and criticality of disasters while prescriptive analytics focuses on management policy related issues for disaster resilience. Likewise, predictive analytics focus on inferences related to imperceptible issues that could influence future tasks including early warning and forecasting while discursive analytics deals with community resilience related aspects such as raising awareness, timely response and collecting feedback based on big data [
43]. Hence, big data technologies improve the effectiveness and speed of linkages between disaster information and appropriate systemic response in Smart Cities [
44]. Compared to conventional cities, within Smart City contexts, rapid or real-time big data applications allows better mitigation and capacity enhancement to recover from extreme events relatively faster [
45]. One example is the development of ‘geospatial big data’ from location-enabled mobile communication devices and other sensor network-based geospatial data acquisition systems; yet, due to the requirements including high-speed Internet connections, advanced network infrastructure, and knowledge of cloud-based computing, use of cloud-based Big Data processing platforms is questionable in different Smart City contexts like developing countries [
46].
Geo-visualisation includes modern digital ways to represent geospatial data and plays an important role in disaster modelling, scenario development, post disaster analysis and during the execution of search and rescue operations [
11]. Geo visualisation is often driven through Geographical Information Systems (GIS). GIS tools are useful for the production and presentation of results obtained from spatial processing and analysis that are ultimately used for better decision-making [
31]. GIS has been broadly used widely used to produce hazard, risk and vulnerability maps to effectively understand and manage risks in cities [
47]. In addition to risk assessments, GIS plays an important role in emergency response and recovery and reconstruction, especially with its capability to analyse real-time data from cameras and sensors [
48]. GIS also assist in deploying location-based emergency services by facilitating the mapping of several contexts within the same area over a period of time so that it helps identify the environmental patterns/ changes in local risk levels [
49].
Sensor-connected buildings, critical infrastructure systems, vehicles, etc. are critical in capturing real-time information about potential vulnerabilities before catastrophic failure [
50]. By using a combination of sensors, for example, seismic sensors, flood sensors, air quality sensors, weather sensors, thermal sensors, motion sensors, and radiation sensors, disaster responders can swiftly assess the scenario, identify potential risks, and take suitable action to mitigate the larger impact [
51]. According to Adeel
, et al. [
52], Wireless Sensor Web (WSW) technology is useful in early warning and situational awareness to prepare communities and assets. Cheikhrouhou
, et al. [
53] highlighted the synergistic combination of wireless sensor networks and 3D graphics technologies where near-real-time 3D true-to-life scenarios can be generated based on sensor data received from the real environment. Sharma
, et al. [
54] explained the prominent use of low-power, low data rate wireless sensor networks (WSN) within the intelligent control system of Smart Cities and Khalifeh
, et al. [
55] highlighted the role of WSN in securing the Smart City from various hazards.
Smart Grid incorporates modern advanced technologies, intelligent algorithms, communication networks, and automation systems into the power system to enhance system efficiency, reliability, resiliency, power quality and cost-effectiveness while providing the customer’s tools to manage energy usage [
56]. In the case of Smart Cities, innovations in smart energy systems and grids are capable of efficient energy consumption/generation and hence are a popular choice especially when renewable energy such as solar and wind energy are integrated [
57]. Smart grid technologies can enhance a city resilience by reducing the length of power outages and consequently reducing the scale and severity of disaster impacts significantly [
50]. Similarly, microgrids can improve the post-disaster resilience significantly. With the ability to operate in ‘island mode’, microgrids continue to supply power in the event the large grid is damaged during an extreme event and they can be deployed rapidly [
58]. Similar benefits for resilience could be gained with the use of smart water grids use [
57].
Wireless Wide Area communication (WWAN) for example Long Term Evolution (LTE), Universal mobile telecommunication system (UMTS), Satellite Cellular, High-Speed Downlink Packet Access (HSDPA); or Wireless Local Area Networks (WLAN) for example, Wi-Fi, Bluetooth, etc. facilities interconnect a large number of heterogeneous mobile smart sensing devices which allows providing crisis management services ranging from first responder localisation to all on-site activities within the smart city area [
59]. Out of the above WWAN mechanisms, LTE/4G networks have the ability to provide technology agnosticism and provider independence, which is important to mitigate disruptions or outages in any one technology or operator [
60]. On the other hand, satellite communication provides reliable communication services in remote or disaster-affected areas where terrestrial communication networks may be unavailable; hence considering the strengths and weaknesses of both, research recommends the integration of satellite and LTE for disaster recovery [
61]. Over the recent decade, innovations in communication technology played a crucial role in terms of ensuring error-free connectivity in Smart Cities amidst the major challenge as a result of the coexistence of a high number of intelligent devices [
62].
The term Location-based services (LBS) is interchangeably used with location services, wireless location services, mobile location-based service, location-enabled services, and location-sensitive services refers to an innovative technology that provides information based on the geographical location (of the user) [
63]. The kinds of location-based technologies that offer consumer data services based on the position of the user are mainly used in emergency and rescue services, navigation and tracking and public alerting and warning [
64]. Supported by wireless communication technology, LBS technology has two approaches 1) the location data is processed on a server and the result is sent to a mobile device 2) location data can be used through an application on the mobile device [
65].
The satellite-based Global Position System (GPS) is the first global location system in use and currently, location-based data can be obtained with one or more of many outdoor and/or indoor positioning determination technologies, classified as terminal/ user-centric, network-centric, and hybrid solutions [
49]. Assisted GPS (AGPS) is an improvement to conventional GPS and was developed to compensate for the weakness of GPS. AGPS is a combination of mobile technology and GPS where it makes use of the local wireless networks for faster location acquisition than conventional GPS with enhanced accuracy[
66]. Besides, satellite-based technology the other popular technology is network-based which receives a signal from cell sites serving a mobile phone to determine the location some popular methods include, Angle Of Arrival (AOA), Time Of Arrival (TOA), Time Difference Of Arrival (TDOA) and hybrid methods [
63]. Positioning as a broad spatial computing area has a large potential in Smart Cities as a means to help re-imagine, review, redesign, and compare alternative infrastructure futures to address risks [
67].
Smart-city-based applications necessitate transparent transactions (verified data/information stored), no single point of failure, data protection and automatic decision-making to ensure the authorization and integrity of transactions and with the immutable decentralized ledger, blockchain technology serves that purpose in securing Smart Cities [
68]. Blockchain technology is able to revolutionise disaster resilience, especially in managing the funding/ aid to refugees [
69]. The smart contract functionality is highlighted in discussing the use of blockchain technology in disaster management as the city’s disaster management policy can be scripted and damages can be logged with costs being estimated early in the recovery process [
70].
A Data Warehouse (DW) is a database that stores an integrated and time-varying data collection derived from operational data and primarily used in strategic decision making [
71]. The evolved concept, of big data warehousing is more popular in the Smart City context which supports fact-based decision-making and is with streaming and predictive capabilities [
72]. Within the disaster resilience scenario DW can play an important role as it consolidates and (ad hoc) analyses data from different (for example emergency response systems, sensors, social media, etc.) while eliminating data redundancy for improved decision making [
73].
Digital twins facilitate comprehensive data exchange and contain simulations, models, and algorithms describing their counterpart (a physical asset, system, or process) including its characteristics and behaviour in the real world [
74]. Urban Digital Twins (UDT) in Smart Cities help them tackle urban complexities by visualizing complex processes in urban systems and their dependencies, simulating possible impacts/outcomes, with particular consideration of the heterogeneous requirements and needs of its citizens to enable collaborative and participatory planning [
12]. Smart Cities with digital twins have the capability to synthesise the unique conditions and characteristics of a community during an extreme event and anticipate the evolution of that community following a disaster [
75]. UDTs support decision makings when planning activities are synchronised, to improve infrastructure system performance, lower planning conflicts, and for the effective use of environmental and social resources [
76]. A digital twin paradigm plays a significant role in a disaster affected city, especially in terms of enhanced situation assessment and decision-making, coordination, and resource allocation [
77]. Linking every element in a city to a digital twin in the cloud allows better monitoring of the performance and detection of flaws [
78].
UAV path planning is envisioned to find the shortest and optimal path with minimum energy consumption and optimal resource utilisation [
79]. Drones have the capacity, responsiveness and portability to increase cellular coverage and bandwidth for disaster relief efforts, criminal surveillance, etc. and they often are considered as a timely solution during disaster rescue missions when regular wireless networks are disrupted [
80]. Information about the disaster-affected areas through aerial images from UAVs helps faster evacuations and delivery of supplies helps through a safe route to even inaccessible locations [
81].
Cyber-Physical Systems simply integrate the physical element and computational element in engineered systems where the sensors, actuators, and other devices are used to interact with the physical world and computer algorithms analyse and process data in real time [
82]. There is only few research that looked at the potential of CPS in disaster resilience which include those that studied about CPS based intelligent structural disaster prevention and reduction system [
83], emergency response [
84], pre-disaster response planning [
85], etc. Smart cities can be viewed as a large-scale implementation of CPS where sensors monitor the physical and cyber components and actuators change the Smart City ecosystem environment [
86]. However while improving the cyber infrastructures CPSs can also introduce security vulnerabilities when CPSs are interfaced with Smart Cities [
87]. Infrastructure risk is one of the most discussed and critical risks in Smart Cities given the physical world and cyber world are integrated (Baker et al., 2019). Therefore CPSs of smart cities should be designed with balancing the cybersecurity capabilities and proactive intelligence against infrastructure risks and vulnerabilities [
88].
BIM is a technology that allows the creation of a digital representation of the functional and physical characteristics of a building. Although the model mainly is used as a shared database to manage a building construction/ facilities throughout its entire project lifecycle it can provide a number of benefits for disaster resilience as well; especially in facilitating post-disaster damage assessment [
89]. It also helps in generating and running simulations of the operation of the building facility and the behaviour of occupants of that building, under normal and emergency scenarios [
90].
Compared to traditional disaster response systems, smart DRS deploy real time data to respond in an efficient and timely manner [
91]. Local communities as the major component of the smart DRS receive information from sensors and share them in order to obtain assistance [
92].
Early warning systems are developed for a range of threats including natural geophysical hazards, biological hazards, industrial hazards, complex socio-political events, human health concerns, and other threats within the urban disaster scenario many research have been carried out on early warning systems where real-time data is used to generate warnings for natural hazards [
93]. Early warning systems developed for Smart Cities often incorporate different technologies like Artificial Intelligence, IoT, and big data analytics to develop more reliable and resilient systems that are faster to predict and detect [
94].
Immersive technology is fundamentally a simulation of reality created by spatial, physical, and visual computers and Virtual Reality (VR), Augmented Reality (AR), And Mixed Reality (MR) have the supremacy to change human-computer relationships with an immersive experience in a digital environment and make digital information meaningful and powerful [
95]. With these technologies being able to capture the dynamic interactions in Smart Cities, the city can better prepare for hazards/ disasters [
96].
3.1.2. Artificial intelligence helps to reduce the cascading effects of the destruction of critical infrastructures and allows rapid recovery [97]. Artificial intelligence (AI) applications, including tracking and mapping, remote sensing techniques, geospatial analysis, robotics, machine learning, drone technology, telecom and network services, smart city urban planning, accident and hot spot analysis, environmental impact analysis, and transportation planning, are the technological components of societal change which drives the societal response to hazards and disasters [98]. Accordingly, machine learning and smart city planning are subsets of artificial intelligence. Studies have found prediction and forecasting, early warning systems, resilient infrastructure, financial instruments, and resilience planning as the AI application areas in disaster resilience [99]. With the speed and better ability to analyse large volumes of disaster related data (compared to humans), AI can generate acceptable forecasts to deploy resources and develop disaster plans [100].
The above reviewed are the most cited technologies and tools for citywide geodata collection and management suggest used for DRR and is linked with its potential applications in the Smart Cities. While technologies and tools ranges within a broad spectrum, there could be more which needs to be researched further to justify their potential in creating disaster resilience within Smart Cities. Below section discuss the technologies and tools focused on the public participation in creating disaster resilience within Smart Cities.
3.1.2. Technologies and Tools for public participation
Crowdsourcing refers to data (by means of ideas, content, services, or even funds) created by a large group of people as a response to an open call or invitation and is based on the underlying argument that a group can provide solutions to a problem more effectively than an expert [
101,
102]. Crowdsourcing applications can be of large importance in creating disaster resilience as they acknowledge a variety of data collection forms so that it broadens the information availability especially during disasters to impacted communities and at the same time allows the affected populations to communicate with the global community [
32]. Data collected through crowdsourcing platforms also help Smart Cities to identify the health conditions of their victimised citizens following a disaster, utilise the resources by better understanding the extent of the disaster, position rescue teams and also help minimise further damage to the environment/ ecosystem[
51]. Through active crisis crowdsourcing not only does the community receives a location-based warning and messages like evacuation routes but also offers benefits to all stages of the disaster life cycle as shown in
Figure 1 [
103].
Volunteered Geographic Information (VGI) is the creation of digital spatial data by groups of people reflecting on their views and geographical knowledge on the web [
104]. Some refer to this as a subset of the crowdsourcing mechanism. According to VGI is more detailed, timely, and of a higher quality in many cases compared to what was provided by the official institutions but at the same time the data quality and reliability are highly variable, undocumented and at times incomplete [
105,
106] and these inconsistencies could lead to errors in disaster related decision making and planning [
107].
Similar to crowdsourcing, web based participatory tools allow the general community to share their ideas, thoughts, views and collaborate over the internet. For example, the web-based participatory surveillance of infectious diseases collects collect real-time information on the distribution of influenza-like illness cases through web surveys [
108]. Other similar examples include a web-based participative decision support platform where the disaster experts, decision makers and the community brainstorm risk mitigation alternatives and select the most appropriate from the proposed [
109] and participatory GIS applications that incorporate local knowledge into GIS where public access and collaborative mapping is promoted [
110].
Social media is a powerful and natural extension of the human sensory system; it includes not only disaster related information shared by the general public but also more trustworthy sources like government authorities, research/ academic institutions and Non-Governmental Organisations (NGOs) [
111]. Social media have been primarily used for disaster management to detect extreme events and hazards, and for emergency responders and relief coordinators to obtain situational awareness through social media users’ feedback and monitoring [
112]. Researchers also study the social-mediated crisis communication patterns to understand the behaviour of social media users (people and community) during disasters which findings could advise on taking resilient measures [
113,
114]. Data from social media is vastly important as they overcome the data unavailability due to remote sensing data is lacking during disasters when geo-temporal gaps take place as a result of satellite revisit time limitations, atmospheric opacity, or other obstructions [
115].
Living Labs are a user-centric innovation setting built on everyday research and practice where stakeholders collaborate to design, test, and validate innovative technologies, solutions, and services [
116]. Living Labs is a platform to construct Smart City solutions including those aimed at disaster resilience [
117]. They help to provide a real-world environment to collaboratively explore, design, test, and implement innovative solutions for disaster resilience [
15].
The above review on tools and technologies that facilitate public engagement suggest that there is a potential to build innovative yet inclusive technologies for all. While there are technologies and tools serves the purpose of engaging society by different means, above mentioned are the most common/ mostly cited. The next section classifies the above discussed technologies and tools based on different criteria.