Architectures

Hybrid, integrated and composable architectures

• architecture: the overall structure and organization of the different parts of the information system
• modularity: the extent to which an information system can be constructed from independent software units with standardized or clearly defined functions
• interoperability: the ability of two or more information systems to share data, information, or processing capabilities
• hybrid gis architecture: store geospatial and non-geospatial separately
  • spatial data stored in a set of system files
  • non spatial data stored in a database
  • records in the spatial files are linked to tuples in the non spatial database using a set of common keys
  • pros: modular
  • cons: need to maintain integrity, security, and reliability more difficult
• Integrated architecture: store all data in a single databases
  • object-oriented databases

Syntactic and sematic heterogeneity

• exchanging, sharing and integrating data is fundamental for any GIS architecture
• barriers to data sharing
  • syntactic heterogeneity: systems use incompatible encoding of formats for information
    • data must be converted into compatible formats
  • semantic heterogeneity: systems use different of incompatible meanings
    • difficult to reconcile
• transfer formats address syntactic heterogeneity by providing a standard intermediate format for data conversion
• data dictionary can address semantic heterogeneity
  • spatial data transfer standard
• Spatial data infrastructures(SDI): strategies for sharing and coordinating geospatial data

Distributed Systems

• a collection of multiple information system connected via a digital communication network that synchronously co-operate to complete a computing task
  • mainframe network
  • Peer to peer network
• protocol is standard format for communication
  • HTTP
  • MQTT: lightweight publish-subscribe protocol for machine-to-machine in low bandwidth environments

Distributed databases

• pros
  • decentralization
  • availability and reliability
  • performance
  • modularity
• cons
  • complexity
  • security
  • integrity
• relational distributed databases
  • fragmentation
  • replication

location-aware Computing

• context aware computing: the use of sensors and other sources of information about a user's context to provide more relevant information and services
• location-aware computing: utilize information about a user's current location to provide more relevant information and services to that user
• pervasive computing
• mobile computing
• active: rely on signal transmitted from beacons
  • proximity (cell phones) determine location by identifying nearest beacon
  • triangulation (GPS) determine location using geometry of beacons
    • radio wave signals transmit exact time and that satellite's position
    • distance is determined by time it takes the signal to reach receiver
• passive: do not rely on signals transmitted from beacons
  • motion tracing(speed and direction sensors) track movement over time determine displacement
  • scene analysis (digital camera) analyze images from digital camera
• sensor accuracy and precision
  • accuracy: the closeness of data from a sensor to the correct value(s)
  • precision: the level of detail of the data generated by a sensor
• Location-based services(LBS): integrate and process information from a variety of sources: db, sensors, mobile
  • position
  • tracking
  • mobile resource allocation

How do we protect an individual's privacy when using location-aware services (blockchain)