Visualizing Information in Global Networks in Real TimeDesign, Implementation, Usability Study

Transparent Internet Caching (TIC)• A Research project at Ericsson

Research aiming to developing a prototype for demonstrating various algorithms to be used for caching in Content Delivery Networks (CDN).

• Content Delivery Networks are today used for distributing web content such as video in a decentralized fashion. This allows for more efficient utilization of bandwidth and localization of content.

Problem Definition• Demonstrate the TIC

prototype to clients.• A means to study the

algorithms in real time.• A graphical user interface

for visualizing the information in the caching system.

Goals and Research QuestionsImplementation and Design

• To propose a design for a visualization tool for visualizing data in nodes and links in a global computer network.

• Gain practical hands-on experience with implementing and evaluating the visualization tool.

• Which are the technical challenges or problems a developer must face when designing and implementing a visualization tool or a particular visualization technique? How can these problems be dealt with?

• Which modalities or visualization methods are most suitable for presenting the data supplied by the TIC prototype?

Usability Evaluation

• Perform a qualitative usability test focusing on gaining an understanding of the users behavior, their preferences for different display methods/modalities and the cognitive processes involved when users are tasked with using the visualization tool.

• What can we learn about the users of this particular type of system and how do we design for their specific needs and abilities?

• Which modalities or visualization methods do the users prefer and why?

Information Visualization• Information Visualization is

a human cognitive process.• Representation – the visual

encoding of data.• Presentation – the selection

and layout of encoded data.

• Interaction – manipulation of the users’ view of data.

...to form a mental model or mental image of something.

(Spence, 2007).

The Geographic Paradigm• Many Information

Visualization principles are rooted in the geographical paradigm, which is loosely related to the more generic use of spatial metaphors in information visualization and virtual environments.

• Example: Minard’s map of Napoleon’s march to and retreat from Moscow.

The Evolution of Internet Visualizations• The ARPANET in 1969. Only

four nodes.• Up until 1987 the ARPANET

is small enough to be visualized fully on a single sheet of paper.

• First visualizations of the network overlaid on a geographic map.

The Evolution of Internet Visualizations• Visualization of the Billion-

byte inbound traffic on the NSFNET T1 backbone in 1991 show only a subset of the network.

• Access requests to NCAA's WWW server complex in 1995 and Geographic visualization of the ”Mbone” show a globe map representation, curved links and cumulative bars.

Prototyping and Usability Testing• Five prototyping iterations.• Each iteration was followed

by a focus group meeting with 4-8 users.

• Paper prototyping was used during the first two iterations.

• The prototypes developed during iteration 3, 4 and 5 were done in software.

• Usability tests were held after the last two iterations.

• A total of seven users were tested during the two tests, one user participated in both tests.

Prototype 1 and 2: Paper Prototypes

Prototype 3, 4 and 5

Usability Tests

Results and Conclusions• The geographic

representation helps the users to communicate about the network by providing a geographic context.

• Usability tests reveal problems with insufficient feedback, confusion caused by non-standard behavior in the GUI, functionality that was accessible outside of its own context and bad default values.

• It is difficult to communicate for the users how a GUI using 3D-graphics and a lot of interaction will look like. Stop motion animation can be a useful and cost efficient tool for the interaction designer.

• 30-45 minutes to learn by exploration.

• Users perform well despite high cognitive load.

• Users adapt and refine their mental model.

• Users do not want to suppress information.

• 3D-view dependant on usable navigation.

Future Work• Evaluate how v1.0 stands

up against prototype 5.• Plotting scenarios side by

side.• Study users during a demo-

session.• Still missing some

important features such as legends.

• Port software to C++/Objective-C and evaluate how this affects performance.

Demowww.samimatilainen.com/thesis/