Information Spectrum Approach to the Source Channel Separation Theorem

A source-channel separation theorem for a general channel has recently been shown by Aggrawal et. al. This theorem states that if there exist a coding scheme that achieves a maximum distortion level d_{max} over a general channel W, then reliable communication can be accomplished over this channel at rates less then R(d_{max}), where R(.) is the rate distortion function of the source. The source, however, is essentially constrained to be discrete and memoryless (DMS). In this work we prove a stronger claim where the source is general, satisfying only a "sphere packing optimality" feature, and the channel is completely general. Furthermore, we show that if the channel satisfies the strong converse property as define by Han & verdu, then the same statement can be made with d_{avg}, the average distortion level, replacing d_{max}. Unlike the proofs there, we use information spectrum methods to prove the statements and the results can be quite easily extended to other situations

A Universal Decoder Relative to a Given Family of Metrics

Consider the following framework of universal decoding suggested in [MerhavUniversal]. Given a family of decoding metrics and random coding distribution (prior), a single, universal, decoder is optimal if for any possible channel the average error probability when using this decoder is better than the error probability attained by the best decoder in the family up to a subexponential multiplicative factor. We describe a general universal decoder in this framework. The penalty for using this universal decoder is computed. The universal metric is constructed as follows. For each metric, a canonical metric is defined and conditions for the given prior to be normal are given. A sub-exponential set of canonical metrics of normal prior can be merged to a single universal optimal metric. We provide an example where this decoder is optimal while the decoder of [MerhavUniversal] is not.Comment: Accepted to ISIT 201

On the calculation of the minimax-converse of the channel coding problem

A minimax-converse has been suggested for the general channel coding problem by Polyanskiy etal. This converse comes in two flavors. The first flavor is generally used for the analysis of the coding problem with non-vanishing error probability and provides an upper bound on the rate given the error probability. The second flavor fixes the rate and provides a lower bound on the error probability. Both converses are given as a min-max optimization problem of an appropriate binary hypothesis testing problem. The properties of the first converse were studies by Polyanskiy and a saddle point was proved. In this paper we study the properties of the second form and prove that it also admits a saddle point. Moreover, an algorithm for the computation of the saddle point, and hence the bound, is developed. In the DMC case, the algorithm runs in a polynomial time.Comment: Extended version of a submission to ISIT 201

An Estimated New Keynesian Model for Israel

We formulate and estimate a small New Keynesian model for the Israeli economy. Our goal is to construct a small but still realistic model that can be used to support the inflation targeting process. The model contains three structural equations: An open economy Phillips curve for CPI inflation (excluding the housing component), an aggregate demand curve for the output gap and an interest parity condition for the nominal exchange rate. The model is closed with an interest rate reaction function (Taylor-type rule) and an ad hoc equation for the housing component of the CPI, which is dominated by exchange rate changes. In the specification of the model we had to pay special attention to the crucial role of the exchange rate in the transmission of monetary policy in Israel, which has a direct effect on almost 60 percent of the CPI. The model is estimated by the GMM method, using quarterly data for the period 1992:I to 2005:IV. In the estimation of the structural equations we tried to remain as close as possible to the theoretical formulation by restricting the dynamics to one lag at most. We use the model to characterize an "optimal" simple interest rate rule. We find that the monetary authority should respond to an hybrid backward-forward looking rate of inflation and does not benefit from direct reaction to exchange rate measures.

Safety and Efficacy of Vaccination Against Influenza in Patients With Rheumatoid Arthritis

Vaccination against influenza is currently recommended for patients with rheumatoid arthritis (RA). The safety and efficacy of vaccination in patients suffering from rheumatic diseases is still a matter of debate. This review summarizes the studies performed on the safety and immunogenicity of influenza vaccination in patients with RA as well as the rheumatic complications of the vaccine in otherwise healthy persons. Several trials have shown that the vaccine induces an adequate humoral response and does not induce clinical exacerbation of RA. Rheumatic complications (mainly vasculitis) following influenza vaccination in the general population are scarce

A Path to Transformation: Asking “The Woman Question” in International Law

Methods matter, and the discussion over feminist methods in international law is an important one. As Kathrine Bartlett famously noted, “thinking about method is empowering.” It makes us more aware of the nature of what we do and what we aim to improve in the law. Consequently, we can act more effectively when we examine legal structures and do it with a stronger sense of commitment towards our feminist work. Methods are also the fundamental means by which we produce “valid knowing.” The discussion of feminist methods in international law is one that engages with the combination of rules and assumptions that shape and delimit our views about the exclusion of women’s experiences from this doctrine. Methods determine the ways within those limits by which we aim to assert truth claims, determine our possibilities and conclusions, and establish the grounds for legal reform. Our chosen method defines what we consider as evidence and what we accept as proof. Yet, it cannot guarantee a particular outcome or even the right one. Rather, it provides a sense of discipline in our analysis