ICHG Posters

an iPad application


This project produced an Apple iOS application for navigating the poster venue of the 61st Annual Meeting of the American Society of Human Genetics (ICHG) 2011 in Montreal. It was initially thought of by Moore so that the group can communicate with each other at the conference to efficiently browse posters. It turns out that the devices's capability of using the Bluetooth short-range radios also forms an example of Delay-Tolerant Network (DTN). Collection and analysis of data yields interesting real-life observation for studying such networks. The app can be downloaded from the Apple App Store.


  • Yuanzhu Chen — Memorial University of Newfoundland, Canada
  • Jason Moore — Dartmouth College, USA
  • Walter Taylor — Dartmouth College, USA
  • Sam Coxon


This iPad application has a map-centric user interface and runs on iOS version 4.2 or later. It allows users to browse information about posters presented at the conference and facilitates commenting on the posters and sharing these comments. It uses the Bluetooth radio of the device to transfer messages in a peer-to-peer fashion. As it is used, it records how messages propagate among devices in the XML format. In its "Settings" panel, the user can submit the collected data to a server side program to a Web server.
  • User interface

    The user interface consists of a map and a toolbar. The map portion displays a PDF map published on the ICHG Web site. It supports touch gestures including pinch zooming, panning, and tapping. The user can reposition the viewport by zooming in and out and by panning. The posters areas are on the left and right hand thirds on the map. It responds to tapping by presenting a pop-over window containing the poster's abstract. In addition, it also shows how many messages there are related to this poster. It can also disclose a list of such messages for further reading. A user can compose a message about this particular poster from here, e.g. their <PosterID> field have the value of 325F.

    The toolbar provides access to the Message Center, Peer List, Day Picker, and Settings Panel. They are activated by button pressing to achieve the following.

    1. Message Center — To view a list of all user-generated messages and to provide a message composition window. Messages composed here are generic messages and their <PosterID> field have the value of (generic).
    2. Peer List — To provide a list of which other users are on and off line. This is a table view of three sections. The first section is a list of peers who are currently online. The second section is a list of offline peers who were visible before. The third section only contains the peer's own name. This can later be extended to allow the user to show or hide messages from a particular user on the map user interface,
    3. Day Picker — To select which of the three days when posters are presented. The 2011 ICHG has three poster sessions, i.e. 2-4pm on Wednesday, Thursday, and Friday. There are over 500 poster boards at the venue, each can display two posters of a given day. With the day picker, a user can decide which day's posters should be shown in window after tapping the board.
    4. Settings Panel — To change basic settings and submit recorded data to the server. In the current implementation, changing the value of the group or peer name is disabled. The user can reset the Bluetooth data connection here to achieve a clean state. The data submission sends the recorded message propagation records to our server side program.

  • Messaging

    Users are grouped according to their group names session ID in iOS development terms). By default, all devices from our group share the same group name of "MooresLab". Other groups attending the conference can use their own group names to establish intra-group messaging. A user can generate generic messages or ones specific to a poster. In either case, these messages are intended for all other group members.

    To do this, the app uses the Bluetooth radio on the iPad to achieve short-range wireless communication. Since it does not rely on any infrastructure at the conference venue, such as Wi-Fi access points or cellular base-stations, it can function in a wider scope of settings. The Bluetooth radio on-board of the iPad has a transmission range of up to 100 meters in a not-so-"noisy" environment. At conference venues, however, its range will be a fraction of that. In general, two devices can be out of range of each other frequently, depending on where the users are and how they move. Thus, a device will "mechanically" transport messages from one location to another as its user moves around. When the app detects other group members within range, it swaps messages with them. As a result, a message propagates among devices belonging to the same group until it reaches everybody. Apparently, messages delivered as such are not "instant".

  • Recording and submission

    The user-generated messages and their metadata, such as the time it is generated and received, are recorded on the device. After the conference, the user can submit these data to the server side program running on the Web server of Computer Science Department, Memorial University. In addition to user-generated messages, the app also automatically generates dummy messages to ensure sufficient messages are injected to the network. These robot messages are also recorded and submitted along with the user-generated ones.
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Copyright by Yuanzhu Chen ©