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Yearly Archives: 2018
CWBound: boundary node detection algorithm for complex non-convex mobile ad hoc networks
Efficient message forwarding in mobile ad hoc network in disaster scenarios is challenging because location information on the boundary and interior nodes is often unavailable. Information related to boundary nodes can be used to design efficient routing protocols as well as to prolong the battery power of devices along the boundary of an ad hoc network. In this article, we developed an algorithm, CWBound, which discovers boundary nodes in a complex non-convex mobile ad hoc (CNCAH) networks.
Experiments show that the CWBound algorithm is at least 3 times faster than other state-of-the-art algorithms, and up to 400 times faster than classical force-directed algorithms. The experiments also confirmed that the CWBound algorithm achieved the highest accuracy (above 97% for 3 out of the 4 types of CNCAH networks) and sensitivity (90%) among the algorithms evaluated.
The author’s version of a work that was accepted for publication can be downloaded from http://eric.lostcity-studio.com/wp-content/uploads/2019/08/CWBound.pdf. Se-Hang, Cheong, and Yain-Whar Si. "CWBound: boundary node detection algorithm for complex non-convex mobile ad hoc networks." The Journal of Supercomputing (2018): 1-20.
Design and Implementation of Lifeline Emergency Ad Hoc Network
There are real cases where mobile phones have been contributed for successful rescues in recent catastrophic disasters. Examples of such cases have been reported in history.
- http://mashable.com/2010/01/20/haiti-iphone-survivor/#mKSyzKKquiqy
- http://lubbockonline.com/filed-online/2011-10-24/5-earthquake-survivors-saved-rubble-turkey
- http://www.asiaone.com/News/Latest%2BNews/Asia/Story/A1Story20110224-265107.html
However, Public Switched Telephone Networks (PSTN), including cellular networks could be disrupted during natural disasters, such as earthquakes, hurricane, tsunami, etc.
In such situations, mobile phone users may not be able make emergency calls since cellular signal is likely to be unavailable due to the destruction of land-based network infrastructures. Although we cannot assume that all people trapped under debris will have access to their mobile phones, it is possible that some of them may still have access to their mobile phones when they are trapped under the debris or when they are waiting to be rescued.
This paper proposes a system for automatically forming ad hoc networks using mobile phones and battery-powered wireless routers for emergency situations. The system also provides functions to send emergency messages and identify the location of victims based on the network topology information.
The author’s version of a work that was accepted for publication can be downloaded from http://eric.lostcity-studio.com/wp-content/uploads/2019/08/Saving-Lives：Design-and-Implementation-of-Lifeline-Emergency-Ad-Hoc-Network.pdf. Se-Hang Cheong, Yain-Whar Si, Leong-Hou U. “Saving Lives: Design and Implementation of Lifeline Emergency Ad Hoc Network”, International Journal of Pervasive Computing and Communications, Accepted and to appear.
Architecture of Force-directed Algorithms
A graph layout problem, or visualization problem, refers to a set of nodes and a set of relationships (edges) built on top of this set of nodes, calculating the position of the nodes and drawing each edge as a line or curve.
One of the most important research directions in the visualization technology of graphs is the study of graph layout algorithms. The core content of the graph layout algorithm research is to study how to display the graph structure in a better way. E.g. force-directed algorithms.
The comprehensive workflow for classical force-directed algorithms are summarized below:
- Davidson and Harel Algorithm
- LinLog Algorithm
- Kamada-Kawai Algorithm
- Fruchterman Reingold Algorithm
- ForceAtlas2 Algorithm
1. Davidson and Harel Algorithm
2. LinLog Algorithm
3. Kamada-Kawai Algorithm
4. Fruchterman Reingold Algorithm
5. ForceAtlas2 Algorithm
