Further Results on Geometric Properties of a Family of Relative Entropies

This paper extends some geometric properties of a one-parameter family of relative entropies. These arise as redundancies when cumulants of compressed lengths are considered instead of expected compressed lengths. These parametric relative entropies are a generalization of the Kullback-Leibler divergence. They satisfy the Pythagorean property and behave like squared distances. This property, which was known for finite alphabet spaces, is now extended for general measure spaces. Existence of projections onto convex and certain closed sets is also established. Our results may have applications in the R\'enyi entropy maximization rule of statistical physics.Comment: 7 pages, Prop. 5 modified, in Proceedings of the 2011 IEEE International Symposium on Information Theor

Loss of adiabaticity with increasing tunneling gap in non-integrable multistate Landau-Zener models

We consider the simplest non-integrable model of multistate Landau-Zener transition. In this model two pairs of levels in two tunnel coupled quantum dots are swept passed each other by the gate voltage. Although this 2 * 2 model is non-integrable, it can be solved analytically in the limit when the inter-level energy distance is much smaller than their tunnel splitting. The result is contrasted to the similar 2 * 1 model, in which one of the dots contains only one level. The latter model does not allow interference of the virtual transition amplitudes, and it is exactly solvable. In 2 * 1 model, the probability for a particle, residing at time t -> -\infty in one dot, to remain in the same dot at t -> \infty falls off exponentially with tunnel coupling. By contrast, in 2 * 2 model, this probability grows exponentially with tunnel coupling. The physical origin of this growth is the formation of the tunneling-induced collective states in the system of two dots. This can be viewed as manifestation of the Dicke effect.Comment: 8 pages, 3 figure

Black Box Variational Inference

Variational inference has become a widely used method to approximate posteriors in complex latent variables models. However, deriving a variational inference algorithm generally requires significant model-specific analysis, and these efforts can hinder and deter us from quickly developing and exploring a variety of models for a problem at hand. In this paper, we present a "black box" variational inference algorithm, one that can be quickly applied to many models with little additional derivation. Our method is based on a stochastic optimization of the variational objective where the noisy gradient is computed from Monte Carlo samples from the variational distribution. We develop a number of methods to reduce the variance of the gradient, always maintaining the criterion that we want to avoid difficult model-based derivations. We evaluate our method against the corresponding black box sampling based methods. We find that our method reaches better predictive likelihoods much faster than sampling methods. Finally, we demonstrate that Black Box Variational Inference lets us easily explore a wide space of models by quickly constructing and evaluating several models of longitudinal healthcare data

The Transformation of Microfinance in India: Experiences, Options and Future

The paper looks at the growth and transformation of microfinance organisations (MFO) in India. We first, define microfinance and identify its "value attributes". Having chosen only those MFOs that have microfinance as the core, we look at the transformation experiences. To understand the transformation experiences better, we identify issues that trigger transformation viz: size, diversity of services, financial sustainability, focus and taxation. Having identified these we look at transformation experiences internationally. We examine the Bolivian, Kenyan, Bangladeshi and the Indonesian experience. We then look at the Indian experiences. We argue that the transformation experiences in India are not large in number. However, we have found that there are three forms of organisations that seem to be popular in the microfinance sector - the Non-Banking Finance Companies, the Banks - both Local Area Banks and Urban Co-operative Banks and the Co-operatives. We then argue that in the Indian case, we find that the MFO spins off from the NGO rather than the NGO transforming itself. Having examined various options, we conclude that there is no ideal or easy path for MFOs to mainstream in India. This has implications for regulatory framework. We argue that there should be regulatory changes that allow smaller MFOs to get into more complex forms as they grow organically. We also argue that NGOs should be allowed to invest in the equity of MFOs and MFO promoted banks, as is the case in Bolivia and Africa. We maintain that entry norms on capitalisation for the current forms of organisations (NBFCs, Co-ops and Banks) need not be changed to ensure only genuine MFOs make use of the legislation and not other organisations masquerading as MFOs.

A Lightweight and Attack Resistant Authenticated Routing Protocol for Mobile Adhoc Networks

In mobile ad hoc networks, by attacking the corresponding routing protocol, an attacker can easily disturb the operations of the network. For ad hoc networks, till now many secured routing protocols have been proposed which contains some disadvantages. Therefore security in ad hoc networks is a controversial area till now. In this paper, we proposed a Lightweight and Attack Resistant Authenticated Routing Protocol (LARARP) for mobile ad hoc networks. For the route discovery attacks in MANET routing protocols, our protocol gives an effective security. It supports the node to drop the invalid packets earlier by detecting the malicious nodes quickly by verifying the digital signatures of all the intermediate nodes. It punishes the misbehaving nodes by decrementing a credit counter and rewards the well behaving nodes by incrementing the credit counter. Thus it prevents uncompromised nodes from attacking the routes with malicious or compromised nodes. It is also used to prevent the denial-of-service (DoS) attacks. The efficiency and effectiveness of LARARP are verified through the detailed simulation studies.Comment: 14 Pages, IJWM