US: Researchers at the Northwestern University, US, introduced Crowd Soft Control (CSC) approach to exert limited control over the temporal and spatial movements of mobile users by leveraging the built-in incentives of location-based services (LBS) such as gaming and social applications.
Location-based applications rely on users’ position and orientation to enhance their game play or social networking experience. For instance, a class of games known as augmented reality games use a mobile device’s GPS location along with its camera and compass to overlay virtual information on top of a user’s camera view. Social networking games like Foursquare and Gowalla encourage users to “check-in” at locations to alert their friends to their whereabouts and collect virtual rewards. Researchers argued that by leveraging the incentives of such location-based applications (e.g. offering bonus points for visiting a certain location), users’ actions can be manipulated to achieve a network service’s goal (e.g. taking a measurement at that location).
A CSC deployment includes three key elements: a networked service, (e.g. a noise pollution monitoring service), the set of mobile devices taking part of a game or interacting through a social networking app, and the CSC manager mediating between them. The figure (featured above) illustrates these components and their interactions.
– Networked service: A third-party networked service that submits requests for assignment to participating devices.
– CSC participant devices: Participant mobile devices, such as those of players in a third-party location-based game, registered with the CSC manager and accepting requests from it.
– CSC manager: The manager, acting as a matchmaker, that assigns networked service requests to devices according to a device’s capabilities and physical and temporal location.
The CSC prototype – the mobile device middleware and the CSC manager – includes about 5,000 lines of code in both Python (1,020) and Java (4,258). Soon after the launch, the CSC middleware goes through a device registration procedure. It first determines the sensing capabilities of the device, recording the types and availability of different sensors. It then assigns the device a unique ID, which is stored for future device identification. This information is then uploaded to the CSC manager. The unique ID is used to provide anonymity to participating mobile users. Registration data is stored so that a device’s sensor capabilities, and therefore its ability to provide the requested sensing or action response, can be quickly determined.
To solicit location suggestions, the location-based app makes a call to the CSC middleware passing its current location, the maximum distance the points can be from the current location and number of points to be returned. These parameters limit the scope of the requested targets returned, as well as provide a way for the developer to tailor the results to their individual application. The middleware then contacts the CSC manager, and receives a set of network service targets for the area around the current location.
The library translates these requested targets into a set of points, each of which contain the following information:
– Location: The location desired stated in terms of latitude and longitude, and optionally altitude and heading.
– Action: The type of action to be triggered at the particular location and time.
– Expiration Time: The time when the request is no longer valid; this is used to control the timing and relevancy of actions.
– Ranking: The relative importance of the location. This can be used by the game to differentiate incentives by priority.
Source: Northwestern University