MultiTrack: A Delay and Cost Aware P2P Overlay Architecture

The rapid growth of peer-to-peer (P2P) networks in the past few years has brought with it increases in transit cost to Internet Service Providers (ISPs), as peers exchange large amounts of traffic across ISP boundaries. This ISP oblivious behavior has resulted in misalignment of incentives between P2P networks|that seek to maximize user quality|and ISPs|that would seek to minimize costs. Can we design a P2P overlay that accounts for both ISP costs as well as quality of service, and attains a desired tradeoff between the two? We design a system, which we call MultiTrack, that consists of an overlay of multiple kinds of Trackers whose purpose it is to align these goals. We have mTrackers that form an overlay network among themselves, and split demand from users among different ISP domains while trying to minimize their individual costs (delay plus transit cost) in their ISP domain. We design the signals in this overlay of mTrackers in such a way that potentially competitive individual optimization goals are aligned across the mTrackers. The system could also have a tTracker that acts as a gateway into the system, and ensures that users who are from different ISP domains have a fair chance of being admitted into the system, while keeping costs in check. We prove analytically that our system is stable and achieves maximum utility with minimum cost. We validated our system design using Matlab simulations, and implemented the system on ns-2 in order to conduct more realistic experiments. We showed that our system significantly outperforms two types of systems, one in which user delay is the only control dimension (forwarding traffic without considering the transit prices) and a second system in which transit prices are the only control dimension (localized traffic only). Thus, we conclude that our system, that operates in two dimensions: (1) user delay and (2) transit prices, results in minimum cost and maximum utility for fixed capacity of the system

Evaluating the sustainability of urban agriculture projects

Evaluating the sustainability of urban agriculture projects. 5. International Symposium for Farming Systems Design (AGRO2015

Viral processes by random walks on random regular graphs

We study the SIR epidemic model with infections carried by $k$ particles making independent random walks on a random regular graph. Here we assume $k\leq n^{\epsilon}$, where $n$ is the number of vertices in the random graph, and $\epsilon$ is some sufficiently small constant. We give an edge-weighted graph reduction of the dynamics of the process that allows us to apply standard results of Erd\H{o}s-R\'{e}nyi random graphs on the particle set. In particular, we show how the parameters of the model give two thresholds: In the subcritical regime, $O(\ln k)$ particles are infected. In the supercritical regime, for a constant $\beta\in(0,1)$ determined by the parameters of the model, $\beta k$ get infected with probability $\beta$, and $O(\ln k)$ get infected with probability $(1-\beta)$. Finally, there is a regime in which all $k$ particles are infected. Furthermore, the edge weights give information about when a particle becomes infected. We exploit this to give a completion time of the process for the SI case.Comment: Published in at http://dx.doi.org/10.1214/13-AAP1000 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

SMART - IWRM - Sustainable Management of Available Water Resources with Innovative Technologies - Integrated Water Resources Management in the Lower Jordan Rift Valley : Final Report Phase II (KIT Scientific Reports ; 7698)

SMART was a multi-lateral research project with partners from Germany, Israel, Jordan and the Palestinian Territories. The overall goal was to develop a transferable approach for Integrated Water Resources Management (IWRM) in the water shortage region of the Lower Jordan Valley. The innovative aspect addressed all available water resources: groundwater and surface waters, but also wastewater, brackish water and flood water that need to be treated for use

Transboundary water management in Africa: challenges for development cooperation

"In the past the joint use of transboundary rivers was often seen as entailing major security-related conflict potentials. In the late 1980s and particularly during the 1990s blaring headlines like 'Water Wars,' 'Water More Precious than Gold,' or 'Water Seen as Fuel for Military Conflicts' drew the public's attention to potential or existing use conflicts along transboundary water bodies. Rising consumption and the asymmetrical hydropolitical relations between countries fuelled the assumption that water shortages would just about inevitably lead to violent conflict. A much-cited example was conflict among the riparian countries along the Nile and Euphrates- Tigris; the relations between the riparian countries of Southern Africa were likewise seen as a potential source of conflict." (excerpt). Contents: Lars Wirkus, Volker Böge: Transboundary water management on Africa's international rivers and lakes: current state and experiences (11-102); Axel Klaphake, Olivia Voils: Cooperation on international rivers from an economic perspective: the concept of benefit-sharing (103-172); Malte Grossmann: Cooperation on Africa's international waterbodies: information needs and the role of information-sharing (173-236); Erik Mostert: How can international donors promote transboundary water management? (237-288); Waltina Scheumann, Susanne Neubert: Recommendations on development cooperation in transboundary water management (289-319)