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If a linear block code C of length n has a Tanner graph without cycles, then maximum-likelihood soft-decision decoding of C can be achieved in time O(n 2). However, we show that cycle-free Tanner graphs cannot support good codes. Specifically, let C be an (n, k, d) linear code of rate R = k/n that can be represented by a Tanner graph without cycles. We(More)
We consider the problem of efficiently reconciling two similar sets held by different hosts while minimizing the communication complexity , which we call the set reconciliation problem. We describe an approach to set reconciliation based on a polynomial encoding of sets. The resulting protocols exhibit tractable computational complexity and nearly optimal(More)
— The erasure resilience of rateless codes, such as Luby-Transform (LT) codes, makes them particularly suitable to a wide variety of loss-prone wireless and sensor network applications, ranging from digital video broadcast to software updates. Yet, traditional rateless codes usually make no use of a feedback communication channel, a feature available in(More)
— We propose a new framework for providing robust location detection in emergency response systems, based on the theory of identifying codes. The key idea of this approach is to allow sensor coverage areas to overlap in such a way that each resolvable position is covered by a unique set of sensors. In this setting, determining a sensor-placement with a(More)
We propose a novel framework for location detection with sensor networks, based on the theory of identifying codes. The key idea of this approach is to allow sensor coverage areas to overlap so that each resolvable position is covered by a unique set of sensors. In this setting, determining a sensor-placement with a minimum number of sensors is equivalent(More)
Modern Personal Digital Assistant (PDA) architectures often utilize a wholesale data transfer protocol known as " slow sync " for synchronizing PDAs with Personal Computers (PCs). This approach is markedly inefficient with respect to bandwidth usage, latency, and energy consumption, since the PDA and PC typically share many common records. We propose,(More)
— Modern Personal Digital Assistant (PDA) architectures often utilize a wholesale data transfer protocol known as " slow sync " for synchronizing PDAs with Personal Computers (PCs). This approach is markedly inefficient with respect to bandwidth usage and latency, since the PDA and PC typically share many common records. We propose, analyze, and implement a(More)
We consider the problem of finding a minimum identifying code in a graph, i.e., a designated set of vertices whose neighborhoods uniquely overlap at any vertex on the graph. This identifying code problem was initially introduced in 1998 and has been since fundamentally connected to a wide range of applications, including fault diagnosis, location detection,(More)
Wireless Sensor Networks (WSNs) provide an important means of monitoring the physical world, but their limitations present challenges to fundamental network services such as routing. In this work we utilize an abstraction of WSNs based on the theory of identifying codes. This abstraction has been useful in recent literature for a number of important(More)
—We experimentally investigate the benefits of multi-hop networking for intra-car data aggregation under the current state-of-the-art Collection Tree Protocol (CTP). We show how this protocol actively adjusts collection routes according to channel dynamics in various practical car environments, resulting in performance gains over single-hop aggregation.(More)