# Digital Systems in Smart City and Infrastructure: Digital as a Service
## 5 Digital Systems
### Information Technology Systems  
Information Technology (IT) systems enable the required services for the Smart Infrastructure business, operators and managers to perform their tasks. IT systems have gradually become more flexible; rather than dedicated access from a fixed computer, currently IT services can be accessed by mobile phones via specific apps. Although the boundaries of user accessibility are expanded, CyberSecurity risks and identity theft also increases as any attacker can get access remotely to private hosted systems.  
Email Systems transmit digital information in the form of messages using Simple Mail Transfer Protocol (SMPT) protocols with additional calendar and event management applications. Email Systems permits remote computer or Mobile phone server access via Webmail, Internet Message Access Protocol (IMAP) or Post Office Protocol (POP); the difference between them is the synchronization with the email server.  
Ticketing Systems invoices users of the Smart Infrastructure for accessing its services such as Railway Stations or Airports. Tickets are gradually evolving from paper based to Smart Cards or Mobile Apps. Usually ticketing required a physical Gateline, however with Digital technologies such as RFID and video analytics; those physical barriers are becoming virtual. In addition, the integration of private ticketing system and banking IT infrastructure enables the outsourcing of contactless bank debit cards.  
Document Management System (DMS) stores digitally documents in the cloud for resilience; the documents can be shared and accessed simultaneously by a group of users in collaborativelyworking with automatic revisions. Although DMS systems manage documents in their native file format (.DOC,.XLS,.PDF), their Web interface also interacts content with a.HTML extension.  
Timesheets System is used for automatic time management, billing and payroll. The Smart Infrastructure users can book holiday time, time off, sick days with integration to a digital calendar. Timesheet system enables integration with other online systems such as accounting, billing project management systems, payroll systems and resource scheduling.  
Database Warehouse Systems (DWS) stores data from different resources of the Smart Infrastructure Business, produces reports and performs data analytics. The Smart Infrastructure Leadership is based on Data warehouse Systems to make the final management decisions.  
Enterprise Resource Planning (ERP) System performs integrated management of Smart Infrastructure Business processes, functions and applications enabling data information flows between them. Enterprise Resource Planning Systems provides a real time and continuous updated monitoring of business parameters such as cash flow, asset management, purchase orders, and payroll.  
Intranet System enables a shared Web Portal where information is stored and accessed via Web Pages. The Intranet provides the Smart Infrastructure with the interface for internal communication and collaboration, although Intranets have a vast amount of growing information where it is difficult to find relevant information. Intelligent Search methods can be developed and integrated as Interfaces to personalize information to user while providing search functionality.