Interactive Channel Capacity Revisited

We provide the first capacity approaching coding schemes that robustly simulate any interactive protocol over an adversarial channel that corrupts any $\epsilon$ fraction of the transmitted symbols. Our coding schemes achieve a communication rate of $1 - O(\sqrt{\epsilon \log \log 1/\epsilon})$ over any adversarial channel. This can be improved to $1 - O(\sqrt{\epsilon})$ for random, oblivious, and computationally bounded channels, or if parties have shared randomness unknown to the channel. Surprisingly, these rates exceed the $1 - \Omega(\sqrt{H(\epsilon)}) = 1 - \Omega(\sqrt{\epsilon \log 1/\epsilon})$ interactive channel capacity bound which [Kol and Raz; STOC'13] recently proved for random errors. We conjecture $1 - \Theta(\sqrt{\epsilon \log \log 1/\epsilon})$ and $1 - \Theta(\sqrt{\epsilon})$ to be the optimal rates for their respective settings and therefore to capture the interactive channel capacity for random and adversarial errors. In addition to being very communication efficient, our randomized coding schemes have multiple other advantages. They are computationally efficient, extremely natural, and significantly simpler than prior (non-capacity approaching) schemes. In particular, our protocols do not employ any coding but allow the original protocol to be performed as-is, interspersed only by short exchanges of hash values. When hash values do not match, the parties backtrack. Our approach is, as we feel, by far the simplest and most natural explanation for why and how robust interactive communication in a noisy environment is possible

Interactive Coding Resilient to an Unknown Number of Erasures

We consider distributed computations between two parties carried out over a noisy channel that may erase messages. Following a noise model proposed by Dani et al. (2018), the noise level observed by the parties during the computation in our setting is arbitrary and a priori unknown to the parties. We develop interactive coding schemes that adapt to the actual level of noise and correctly execute any two-party computation. Namely, in case the channel erases T transmissions, the coding scheme will take N+2T transmissions using an alphabet of size 4 (alternatively, using 2N+4T transmissions over a binary channel) to correctly simulate any binary protocol that takes N transmissions assuming a noiseless channel. We can further reduce the communication to N+T by relaxing the communication model and allowing parties to remain silent rather than forcing them to communicate in every round of the coding scheme. Our coding schemes are efficient, deterministic, have linear overhead both in their communication and round complexity, and succeed (with probability 1) regardless of the number of erasures T

Reframing technical change: Livestock Fodder Scarcity Revisited as Innovation Capacity Scarcity: Part 3. Tools for Diagnosis and Institutional Change in Innovation Systems

The exploration of fodder innovation capacity requires tools to undertake the following tasks: (i) Diagnosis of fodder innovation capacity to identify project starting points, including micro and macro elements (ii) Socio-economic benchmarking, and follow-up studies (iii) Pilot innovation cloud process learning/ process-driven intervention correction (iv) Comparative analysis of institutional change processes (iv) Project team process learning And (iv) Project evaluation. There is a wide range of existing tools available to investigate institutional change. This paper reviews these and recommends that an eclectic approach of mixing and matching tools to the emerging circumstances of the research is the best way forward.Technological Change, Agricultural Technology, Livestock, Poverty Reduction, Evaluation, Benchmarking

Next Generation High Throughput Satellite System

This paper aims at presenting an overview of the state-of-the-art in High Throughput Satellite (HTS) systems for Fixed Satellite Services (FSS) and High Density-FSS. Promising techniques and innovative strategies that can enhance system performance are reviewed and analyzed aiming to show what to expect for next generation ultra-high capacity satellite systems. Potential air interface evolutions, efficient frequency plans,feeder link dimensioning strategies and interference cancellation techniques are presented to show how Terabit/s satellite myth may turn into reality real soon

Reframing technical change: Livestock Fodder Scarcity Revisited as Innovation Capacity Scarcity: Part 2. A Framework for Analysis

This is the second in a series of three papers that develop a conceptual framework for a project on livestock fodder innovation. The paper begins by reviewing the evolving paradigms of agricultural research and innovation over the last 30 years or so and explains the emergence and relevance of the innovation systems concept to agricultural development. The paper then presents a framework for exploring fodder innovation capacity. This framework gives particular emphasis to the patterns of interaction needed for innovation and the policy and institutional settings needed to enable these processes. The paper concludes with some comments on the difficulties of measuring institutional change and the desirability of tracking institutional change and its relationship to welfare outcomes.Technological Change, Agricultural Technology, Livestock, Poverty Reduction, Institutional Change, Welfare Outcomes