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2009-09-15 QBE, Google Maps crowdsourcing

posted Sep 18, 2009, 5:16 PM by Unknown user   [ updated Sep 18, 2009, 6:17 PM by Eddie Woo ]

Query By Example (QBE)

A query is an operation to match criteria. QBE is a competitor/complement to SQL from the 1970s - while QBE and SQL compete as methods of query, QBE relies on SQL to operate.

Field Example
Due date




This QBE form is sent to a QBE Parsing Enegine (parsing means to interpret, and an engine is something that converts input to output) for analysing and ultimately the construction of an SQL query. In this way, QBE is effectively a shell for SQL.

Advantages of QBE include:
  • Less time needed to make a query
  • Less technical training required for use

Google Maps crowdsourcing

For further details, see IPT: Live Traffic Data

Crowdsourcing is the practice of relying on the end users of an information system to provide content – usually each user provides a small portion. It is a form of collaboration, and is generally beneficial to all who are involved. The compiled content is usually provided back to the contributors. A familiar mainstream example of Crowdsourcing is the system of collaborative editing used on the website Wikipedia. It is a play on the word outsourcing.

Hardware used in this system include:
  • Google web servers
  • GPS devices
  • Visual display units
  • Satellites
  • Transponders
  • Cabling
  • Base towers for mobile phone cell networks
  • Wireless network interface cards
People in the environment include vehicle drivers who send data about the traffic but do not use the content provided by the system. Participants include system developers, maintainers, engineers, and employees of Google corporation. End users include everyone who uses the system, using computers and using GPS devices.

Data flow diagram:

The resulting data could be rendered inaccurate under these circumstances:
  • A car is intentionally moving slowly on a road, and it is the only car with the Crowdsourcing to Google Maps capacity on that road
  • Google intentionally corrupts the data (e.g. under pressure from governments)
  • Technical problems / faulty technology  – miscalculation, incorrect use of units, incorrectly calibrated clocks (and hence incorrect timestamps for calculation)
  • Miscommunication – traffic is colour-coded, but what criteria is used to colour-code is questionable, as it may cause problems if colour-coding is relative, and two very different roads are being compared.
  • Confusion with satellite imagery (colour-coding)
Social issues and ethical issues raised by this system include:
  • Privacy. Although Google insists that data is largely stripped of any personally identifiable data, whether or not they fulfil this promise is unknown to end users and people in the environment. It is an ethical issue if Google stores personally identifiable data without consent.
  • Accuracy. As aforementioned, there are many ways in which the data can become biased or inaccurate. If the data is indeed inaccurate/biased, it is unreliable; however, end users may be unaware and continue to trust the system. This may raise social problems – for example, an ambulance may rely on the system to find the quickest route to an emergency, but then discover that the system was faulty, and ultimately fail to arrive to the emergency on time.
  • Cost. This system requires a lot equipment and software, and relies heavily on infrastructure. Google insists that it will provide the service for free, but whether or not they will be able to continue to do so under a changing economy is a social issue.
  • Public safety. Terrorists could easily use this system to target roads as part of a strategy to cause mass destruction. For example, they could target congested roads to maximise the amount of casualties, or use these roads to limit the speed of which emergency vehicles can access an accident site. This is an ethical issue.
  • Road safety. This system could easily encourage people to look at their GPS screen while driving, and hence cause accidents as a result of vehicle drivers failing to look at the road.
  • Changing nature of work. Many radio stations currently provide a similar service in the form of “traffic updates”. These people may find their jobs endangered.