A Class of Decomposable Poverty Measures With Public Transfers

This paper proposes a class of decomposable poverty measures. It incorporates ideas of flexible minimum basic requirement norms, relative deprivation and the presence of public transfer systems. Public transfers oftentimes take the form of implicit transfers and are not usually reflected in the reported income figures. Depending on the access and usage of public transfer systems, real consumption possibility can be very different for different individuals. This paper demonstrates that a poverty measure can be used in a straightforward manner to derive a metric to evaluate the efficiency of the public transfer systems to reach their intended targets. Some of the policy implications are also provided.

Training a Feed-forward Neural Network with Artificial Bee Colony Based Backpropagation Method

Back-propagation algorithm is one of the most widely used and popular techniques to optimize the feed forward neural network training. Nature inspired meta-heuristic algorithms also provide derivative-free solution to optimize complex problem. Artificial bee colony algorithm is a nature inspired meta-heuristic algorithm, mimicking the foraging or food source searching behaviour of bees in a bee colony and this algorithm is implemented in several applications for an improved optimized outcome. The proposed method in this paper includes an improved artificial bee colony algorithm based back-propagation neural network training method for fast and improved convergence rate of the hybrid neural network learning method. The result is analysed with the genetic algorithm based back-propagation method, and it is another hybridized procedure of its kind. Analysis is performed over standard data sets, reflecting the light of efficiency of proposed method in terms of convergence speed and rate.Comment: 14 Pages, 11 figure

Enhanced Raman and photoluminescence response in monolayer MoS2_2 due to laser healing of defects

Bound quasiparticles, negatively charged trions and neutral excitons, are associated with the direct optical transitions at the K-points of the Brillouin zone for monolayer MoS$_2$. The change in the carrier concentration, surrounding dielectric constant and defect concentration can modulate the photoluminescence and Raman spectra. Here we show that exposing the monolayer MoS$_2$ in air to a modest laser intensity for a brief period of time enhances simultaneously the photoluminescence (PL) intensity associated with both trions and excitons, together with $\sim$ 3 to 5 times increase of the Raman intensity of first and second order modes. The simultaneous increase of PL from trions and excitons cannot be understood based only on known-scenario of depletion of electron concentration in MoS$_2$ by adsorption of O$_2$ and H$_2$O molecules. This is explained by laser induced healing of defect states resulting in reduction of non-radiative Auger processes. This laser healing is corroborated by an observed increase of intensity of both the first order and second order 2LA(M) Raman modes by a factor of $\sim$ 3 to 5. The A$_{1g}$ mode hardens by $\sim$ 1.4 cm$^{-1}$ whereas the E$^1_{2g}$ mode softens by $\sim$ 1 cm$^{-1}$. The second order 2LA(M) Raman mode at $\sim$ 440 cm$^{-1}$ shows an increase in wavenumber by $\sim$ 8 cm$^{-1}$ with laser exposure. These changes are a combined effect of change in electron concentrations and oxygen-induced lattice displacements.Comment: 15 pages, 5 figures, Journal of Raman Spectroscopy, 201

Strain-tunable charge carrier mobility of atomically thin phosphorus allotropes

We explore the impact of strain on charge carrier mobility of monolayer $\alpha$, $\beta$, $\gamma$ and $\delta$-P, the four well known atomically thin allotropes of phosphorus, using density functional theory. Owing to the highly anisotropic band dispersion, the charge carrier mobility of the pristine allotropes is significantly higher (more than 5 times in some cases) in one of the principal directions (zigzag or armchair) as compared to the other. Uniaxial strain (upto 6% compressive/tensile) leads to bandgap alteration in each of the allotropes, especially a direct to indirect bandgap semiconductor transition in $\gamma$-P and a complete closure of the bandgap in $\gamma$ and $\delta$-P. We find that the charge carrier mobility is enhanced typically by a factor of $\approx 5-10$ in all the allotropes due to uniaxial strain; notably among them a $\approx 250$ (30) times increase of the hole (electron) mobility along the armchair (zigzag) direction is observed in $\beta$-P ($\gamma$-P) under a compressive strain, acting in the armchair direction. Interestingly, the preferred electronic conduction direction can also be changed in case of $\alpha$ and $\gamma$-P, by applying strain.Comment: 9 pages and 6 figures; To appear in Phys. Rev.

City-Size and Health Outcomes: Lessons from the USA

In this paper, we compare health outcomes in cities of different sizes. Using 2001 National Health Interview Survey data for adult urban-US population, it is shown that individual health is better in bigger cities compared to small or medium sized ones. This result holds after controlling for potentially confounding variables including age, gender, education, marital status, smoking, income, asset-ownership, and race. Possible sources of selection bias are controlled using many model specifications and population sub-groupings. Although, stiff challenges for healthcare delivery exist for large cities, an aggressive urban health policy should also put strong emphasis on improving health in small and medium sized cities to reduce urban health disparities in the USA. Policy implications for other developed and developing countries are also hypothesized.

Convex optimization over intersection of simple sets: improved convergence rate guarantees via an exact penalty approach

We consider the problem of minimizing a convex function over the intersection of finitely many simple sets which are easy to project onto. This is an important problem arising in various domains such as machine learning. The main difficulty lies in finding the projection of a point in the intersection of many sets. Existing approaches yield an infeasible point with an iteration-complexity of $O(1/\varepsilon^2)$ for nonsmooth problems with no guarantees on the in-feasibility. By reformulating the problem through exact penalty functions, we derive first-order algorithms which not only guarantees that the distance to the intersection is small but also improve the complexity to $O(1/\varepsilon)$ and $O(1/\sqrt{\varepsilon})$ for smooth functions. For composite and smooth problems, this is achieved through a saddle-point reformulation where the proximal operators required by the primal-dual algorithms can be computed in closed form. We illustrate the benefits of our approach on a graph transduction problem and on graph matching