Routing in delay tolerant networks with periodic connections

In delay tolerant networks (DTNs), the network may not be fully connected at any instant of time, but connections occurring between nodes at different times make the network connected through the entire time continuum. In such a case, traditional routing methods fail to operate because there are no contemporaneous end-to-end paths between sources and destinations. This study examines the routing in DTNs where connections arise in a periodic nature. We analyze various levels of periodicity in order to meet the requirements of different network models. We propose different routing algorithms for different kinds of periodic connections. Our proposed routing methods guarantee the earliest delivery time and minimum hop-count, simultaneously. We evaluate our routing schemes via extensive simulation experiments and compare them to some other popular routing approaches proposed for DTNs. Our evaluations show the feasibility and effectiveness of our schemes as viable routing methods for delay tolerant networks. © 2015, Mergenci and Korpeoglu

AutopaR: An Automatic Parallelization Tool for Recursive Calls

Manycore systems are becoming more and more powerful with the integration of hundreds of cores on a single chip. However, writing parallel programs on these manycore systems has become a problem since the amount of available parallel tools and applications are limited. Although exploiting parallelism in software is possible, it requires different design decisions, significant programmer effort and is error prone. Different libraries and tools try to make the transition to parallelism easier, however there is no concrete system to make it transparent to software developer. To this end, our proposed tool is a step forward to improve the current state. Our approach, Autopar, specifically aims at achieving automatic parallelization of recursive applications using static program analysis. It first decides on the recursive functions of a given program. Then, it performs analysis and collects information about these recursive functions. Our analysis module automatically collects program information without requiring any modification in the program design or developer involvement. Finally, it achieves automatic parallelization by introducing necessary OpenMP pragmas in appropriate places in the application. © 2014 IEEE