Analysis of low density codes and improved designs using irregular graphs
STOC '98 Proceedings of the thirtieth annual ACM symposium on Theory of computing
An information-theoretic approach to traffic matrix estimation
Proceedings of the 2003 conference on Applications, technologies, architectures, and protocols for computer communications
Network loss inference with second order statistics of end-to-end flows
Proceedings of the 7th ACM SIGCOMM conference on Internet measurement
Decoding by linear programming
IEEE Transactions on Information Theory
IEEE Transactions on Information Theory
Near-Optimal Signal Recovery From Random Projections: Universal Encoding Strategies?
IEEE Transactions on Information Theory
Network Tomography of Binary Network Performance Characteristics
IEEE Transactions on Information Theory
On the Uniqueness of Nonnegative Sparse Solutions to Underdetermined Systems of Equations
IEEE Transactions on Information Theory
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This paper investigates conditions for an underdetermined linear system to have a unique nonnegative solution. A necessary condition is derived which requires the measurement matrix to have a row-span intersecting the positive orthant. For systems that satisfy this necessary condition, we provide equivalent characterizations for having a unique nonnegative solution. These conditions generalize existing ones to the cases where the measurement matrix may have different column sums. Focusing on binary measurement matrices especially ones that are adjacency matrices of expander graphs, we obtain an explicit threshold. Any nonnegative solution that is sparser than the threshold is the unique nonnegative solution. Compared with previous ones, this result is not only more general as it does not require constant degree condition, but also stronger as the threshold is larger even for cases with constant degree.