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The evolutionary history of a set of species is represented by a phylogenetic tree, which is a rooted, leaf-labeled tree, where internal nodes represent ancestral species and the leaves represent modern day species. Accurate (or even boundedly inaccurate) topology reconstructions of large and divergent trees from realistic length sequences have long been(More)
PLAN (Packet Language for Active Networks) is a new language for programs that form the packets of a programmable network. These programs replace the packet headers (which can be viewed as very rudimentary programs) used in current networks. As such, PLAN programs are lightweight and of restricted functionality. These limitations are mitigated by allowing(More)
Media access control (MAC) mechanism design is a key problem in wireless networking. One problem is hidden nodes, which are allowed to transmit, but which interfere with a receiver causing a collision. Another problem is exposed nodes, which are not allowed to transmit although they would not interfere, thus limiting spatial reuse. MAC designs, like IEEE(More)
— Network survivability is fundamental to information security. Adversaries could compromise network functionality by attacking the physical layer, the medium access control (MAC) layer, or the network layer. Even though security mechanisms for the network layer have been extensively discussed, MAC layer security has not been deeply explored. Leveraging(More)
— We present PLANet: an active network architecture and implementation. In addition to a standard suite of Internet-like services, PLANet has two key programmability features: 1. all packets contain programs 2. router functionality may be extended dynamically Packet programs are written in our special purpose programming language PLAN, the Packet Language(More)
— Hydra is a flexible wireless network testbed being developed at UT Austin. Our focus is networks that support multiple wireless hops and where the network, especially the MAC, takes advantage of sophisticated PHY techniques, such as OFDM and MIMO. We argue that for this domain simulation alone is not adequate and that working prototypes are needed to(More)
A major computational problem in biology is the reconstruction of evolutionary trees for species sets, and accuracy is measured by comparing the topologies of the reconstructed tree and the model tree. One of the major debates in the field is whether large evolutionary trees can be even approximately accurately reconstructed from biomolecular sequences of(More)