Micro-Blog: Sharing and Querying Content Through Mobile Phones and Social Participation

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Micro-Blog Sharing and Querying Content Through
Mobile Phones and Social Participation

• Shravan Gaonkar, Jack Li, Romit Roy Choudhury,
  Landon Cox, Al Schmidt
• Presented by Gregory Teodoro

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A brief overview

• Mobile Computing
• Hardware is increasing in power, and decreasing
  in cost such that basic commodity devices will be
  able to perform work such as participatory
  sensing.
• Mobile phones especially, can be used by
  leveraging their camera, GPS, accelerometers, and
  other such sensors to gather information.
• Using a multitude of these phones over a large
  area it is possible to build a virtual
  information telescope. A visual large scale
  interface, that can quickly shift to small and
  more detailed specifics.
• Combined with these sensors, participating users
  can record multimedia blogs (video, voice,
  pictures, ect.).
• Deeper in, these blogs can be combined with a
  user-based query/answer . (ala services such as
  Cha-Cha, but less personal and more
  public/social)
• Combined, all of these factors form

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the Micro-Blog Service!

• Micro-blog stands to combine all of this
  information
• Idea being to create a network of easily
  accessible, localized information.

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Services - Querying

• Querying Service
• The Micro-blogs main goal is to offer a querying
  services, through use of the influx of sensor
  information, a user can gather information about
  temperature, weather, available Wi-Fi services
• Queries can also require human interaction.
• Questions can be sent out to an area about nearby
  restaurants, locations, the weather, attractions
  ect and then answered by people in the area.

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Services Location-Based

• Queries and blogs can also be superimposed on a
  virtual space (map) or a physical space (a part
  of a city). Float.
• Person A sends out micro-blog about Restaurant X
  in Area Y.
• Person B comes to Area Y and has set an interest
  in information on Restaurants. Since hes in
  Area Y, hed receive Person As microblog about
  the Restaurant X.
• Relies on social participation.

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Potential Applications

• Tourism
• On the fly information about attractions in an
  area, either through blogs or audio/videos.
• Can ask questions about services in an area
  (parking, hotels, ect)
• News Services
• Users send out and report events they see, or
  sensors information can create and offer weather
  announcements.
• Spontaneity of capturing information and easier
  publishing means immediate news reports

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Potential Applications (cont.)

• Micro-Alerts
• Location-aware alerts, an example being a college
  where microblogs can be placed directing users to
  specific buildings.
• Comparable best to floating sticky notes.
• Social Collaboration
• Ability to offer on the fly services, ala
  Craigslist.
• Car Pools and Healthcare Reports for example.
• Can post queries and questions, and qualified
  users can answer them.

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Architecture and Design

• Location based Micro-blogs require a localization
  service.
• GPS, GSM, WiFi, ect
• Issue of potential power consumption and accuracy
  balance.
• Blog are location-tagged then indexed by
  originator, access permissions, themes, ect.
• Client contacts webserver to access and retrieve
  a micro-blog.
• Users can also send queries to specific regions
  R.
• Using the localization, the database can see if
  it has any serviceable blogs to send to the user,
  and attempts to match time, location, and
  permissions.
• If it cannot find an answer, it will send a query
  to phones in the area that are declared
  available, and they may answer the query.
• Any answers are placed onto the map as a new
  micro-blog, and may be deleted after a
  pre-specified lifetime.
• Users will also automatically received
  micro-blogs pertaining to their interests and the
  region they are in, triggered when the phone
  updates its location.

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Block-Diagram of Micro-Blog
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Considerations

• Energy Aware Localization
• Constant running of GPS localization is a heavy
  drain on energy, and may not be required for
  acceptable accuracy.
• Energy Aware Applications
• Applications should adapt to energy needs and
  efficiency versus performance.
• Incentives
• Why would people answer queries if they dont
  have to?
• Location Privacy
• Location-based blogging reveals the bloggers
  general location, security and privacy concerns.
• Spam
• Malicious users may use the service to spam other
  users.
• Content Inaccuracy
• Not all query answers might be correct, and
  malicious users may outright lie.

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Energy Awareness

• Rather than using a single localization scheme,
  we can use a mix.
• Use GPS to find the general location once, then
  use the less expensive WiFi or GSM localizations
  to keep track.
• We only use GPS if we have too, or if the user
  has traveled a distance above a certain
  threshold.
• Using a technique called war-driving, a map of
  WiFi Aps can be created, and then used (by
  detecting if a user is in range) to device a
  users approximate location.

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Interpolated Path
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Problems with this

• Does not achieve optimal usage.
• Sharp turns in a path may not trigger a change in
  the WiFi-estimated distances.
• Will continue to extrapolate the original
  direction of movement, and not the sudden turns.
• Will not correct itself until a new WiFi
  fingerprint is created.

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Energy Aware Applications

• Only updates by GPS when required, or when a blog
  is actually created and placed.
• When not created a blog, it will only updated
  based on Wi-Fi or cell-based localizations, as
  exact location or accuracy may not be required.
• Delay updating and uploading blogs if battery
  power is below a certain threshold.
• Keeps power on the phone in case of an unforeseen
  emergency.

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Incentives

• Why should people answer queries if they dont
  need to?
• Queries can be restricted to social network
• A users friends would be far more likely to
  answer than a stranger.
• Alternatively a give and take approach
• Users would be given query credits based on how
  often they participate and answer other users
  queries.
• Issues with bogus queries, collusion, cliques,
  ect.
• Malicious or misbehaving users can be found
  through use of a direction node with a cost
  representation how often the two nodes query each
  other.
• Monetary costs for sending out queries and
  answers
• Plan is to piggy-back on a value package offered
  by phone providers.

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Locational Privacy

• Location-based blogging reveals the bloggers
  location!
• A trust is required between the users and the
  server administrators at Micro-Blog. A
  fundamental drawback.
• They make the assumption that users are willing
  to trust Micro-Blog.
• Offers a private, social, and a public mode as an
  alternative.

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Spam

• The network can be used send spam to users
• Proposed solution is to limit the amount of
  queries a single user can receive from each group
  (private, social, public) during a time period.
• Blocks any queries past this point
• Does not solve the issue!
• A user can be spammed to use up the number of
  queries they want to receive a day, preventing
  any future legitimate queries from being received.

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Content Inaccuracy

• Not all information will be correct.
• Users will receive a reputation based on other
  users ratings.
• Akin to other social services like Digg.
• The higher a reputation, the more confidence the
  micro-blog will have that their query answer is
  correct.
• Do not publish answers from sources that are not
  confident.
• PROBLEMS!
• A malicious user will be quickly locked out, as
  will unknowledgeable, but they will still be able
  to send out some disinformation
• No methods to stop a malicious user from acting
  legitimate to gather a good reputation, and then
  abusing it
• Ties into group/user collusion as well.

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Implementation

• The Micro-Blog program is placed onto a phone
  client.
• Designed specifically to interrupt the normal
  operations of a phone as little as possible.
• System State
• System begins in Idle mode
• User goes to send a blog
• When finished, blog is sent out, phone is tagged
  with location, and then switches to Sync mode
• Sync Mode
• Phone syncs information with the webserver and
  receives any new, relevant Micro-blogs, then
  returns to Idle
• Log State
• Entered periodically where phone updates its
  status based on sensor data (signal strength,
  temperatures, cameras, WiFi/GSM IDs, ect), then
  returns to Idle
• Query state
• A query was receive and appears on the users
  phone and waits for an action. Either reply or
  ignore. Sends it out, then returns to Idle
• This is also checked periodically.

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State Machine for Micro-Blog
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Web Infastructure

• Phone data is send to a database via TCP, and
  uploading into a MySQL database server, then
  indexed into proper relational tables.
• Blogs in response to an earlier query are sent
  out to the approriate users.
• Apache 2.0 is used to offer HTTP access to the
  Micro-Blog over a web browser, where users can
  request blogs, create blogs, and browse a region
  map.
• Server periodically checks all phones that have a
  live connection and their user-set constraints
  and send queries to them as appropriate.

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Battery Life and Localization

• A mix between localization techniques, and the
  use of battery must be found.
• Findings were done using a Nokia N95 phone.
• Main research was done through the use of
  localization trades off.
• Localization schemes included using combinations
  of WiFi, GPS, and GSM.

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Findings
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Findings (cont.)

• Battery life improved using a mix of the
  localization schemes as appropriate.
• This still had a negative effect on locational
  accuracy
• As far as the application is concerned the
  trade-off of accuracy is worth the improvement of
  battery life
• Methods Attempted
• Wifi with periodic GPS correction
• GSM with periodic WiFi Corrections
• Proposed accuracy error was a max of 125m,
  leading to a total of 25 hours of battery life.
• GSM with periodic WiFi offered the best battery
  life vs. localization error, and is used in the
  Micro-Blog program.

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Findings (Cont.)
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Reception

• Questionnaires were done on participants about
  the application and how they felt about it.
• Great for idling periods, but needs a better GUI.
• Privacy control is absolutely vital, and users
  appreciated the ability to control privacy.
• Incentives may not be an issue if program is
  fun.
• Strong correlation between voice blogs being
  personal, and text blogs being impersonal.
• Best time of day is between 500-900 PM
• Concerns about battery life minimal because
  recharging is easy or imminent.

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Paper Strengths

• Very good ideas about what the software should
  do, and some basic logistics behind it.
• Highly concerned with battery and location
  accuracy, and answers the question about what
  should be used well.
• Lots of future potential in the subject at hands.
• Does attempt hands-on testing and user-base
  interaction.

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Paper Weaknesses

• Ignores a lot of potential networking issues,
  such as sorting through data, dealing with
  traffic, packet loss, congestion, among other
  things
• Glazes over some of the privacy and malicious
  user issues, and does not fully solve them.
• Though it was a user study, not many users were
  involved (only 12), nor were these users varied
  in location, culture, or age.
• Needs a far more extensive study of a user-base
• Paper does admit this as a fault of the study.

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Future Work/Follow Ups

• Location-Privacy in the General Public
• A far broader audience needs to be approached
  with the software and tested.
• Accelerometer usage
• Accelerometers are not used in terms of gauging
  distance travel and localization techniques
• Has potential to be integrated into social
  networking applications (Facebook, MySpace,
  Google)
• Methods of identifying and blocking false content
  need to be developed.

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Questions?