zCap: a zero configuration adaptive paging and mobility management mechanism

Today, cellular networks rely on fixed collections of cells (tracking areas) for user equipment localisation. Locating users within these areas involves broadcast search (paging), which consumes radio bandwidth but reduces the user equipment signalling required for mobility management. Tracking areas are today manually configured, hard to adapt to local mobility and influence the load on several key resources in the network. We propose a decentralised and self-adaptive approach to mobility management based on a probabilistic model of local mobility. By estimating the parameters of this model from observations of user mobility collected online, we obtain a dynamic model from which we construct local neighbourhoods of cells where we are most likely to locate user equipment. We propose to replace the static tracking areas of current systems with neighbourhoods local to each cell. The model is also used to derive a multi-phase paging scheme, where the division of neighbourhood cells into consecutive phases balances response times and paging cost. The complete mechanism requires no manual tracking area configuration and performs localisation efficiently in terms of signalling and response times. Detailed simulations show that significant potential gains in localisation effi- ciency are possible while eliminating manual configuration of mobility management parameters. Variants of the proposal can be implemented within current (LTE) standards

Electromagnetic decays of vector mesons as derived from QCD sum rules

We apply the method of QCD sum rules in the presence of external electromagnetic fields $F_{\mu\nu}$ to the problem of the electromagnetic decays of various vector mesons, such as $\rho\to\pi\gamma$, $K^\ast\to K\gamma$ and $\eta'\to\rho\gamma$. The induced condensates obtained previously from the study of baryon magnetic moments are adopted, thereby ensuring the parameter-free nature of the present calculation. Further consistency is reinforced by invoking various QCD sum rules for the meson masses. The numerical results on the various radiative decays agree very well with the experimental data.Comment: To appear in Phys. Lett.

Optimal monetary policy in an open macroeconomic model with rational expectation

This study is concerned with the choice of the optimal control of money supply for a linear stochastic discrete-time model of an open economy with rational expectations. Optimal control theory is applied to the setting of the stabilization policy. The linear and quadratic loss function is assumed to be the government objective function form. \u27Optimal\u27 indicates that the expected weighted sum of the squares of deviations of the state variables from the target values (or trend values) is minimized. The objectives of the study are (1) to examine the validity of the \u27policy ineffectiveness proposition\u27, (2) to investigate the comparative performances of alternative money supply rules--feedback versus fixed and superior information versus fixed, and (3) to determine whether the structure of the economy is crucial to the effectiveness of the setting of the money supply rule, in the sense that the economy is insulated from random shocks;It is shown that the derived optimal money supply has an effect on the probability distribution of output, price, and other endogenous variables even when public expectations are rational. The variance of endogenous variables will change as alternative money supply rules are applied. It indicates that either the feedback money supply rule or the superior information rule is effective in an economy with rational expectations. The structure of the economy does really matter when choosing the optimal money supply rule of stabilization policy

Umbilic hypersurfaces of constant sigma-k curvature in the Heisenberg group

We study immersed, connected, umbilic hypersurfaces in the Heisenberg group $H_{n}$ with $n$ $\geq$ $2.$ We show that such a hypersurface, if closed, must be rotationally invariant up to a Heisenberg translation. Moreover, we prove that, among others, Pansu spheres are the only such spheres with positive constant sigma-k curvature up to Heisenberg translations.Comment: 28 pages, 6 figure

Umbilicity and characterization of Pansu spheres in the Heisenberg group

For $n\geq 2$ we define a notion of umbilicity for hypersurfaces in the Heisenberg group $H_{n}$. We classify umbilic hypersurfaces in some cases, and prove that Pansu spheres are the only umbilic spheres with positive constant $p$(or horizontal)-mean curvature in $H_{n}$ up to Heisenberg translations.Comment: 32 pages, 2 figures; in Crelle's journal, 201

Price Stabilization in the Taiwan Hog and Broiler Industries: Evidence from a STAR Approach

The paper examines the effectiveness of the price stabilization mechanism for the broiler and poultry industry in Taiwan during the period 1999 to 2008. After presenting some background information on the domestic marketing system and price stabilization mechanisms for the broiler and pork industry in Taiwan, the paper discusses the smooth transition autoregressive (STAR) methodology. Monthly hog and broiler price data from 1999 to 2008 at farm, import and retail levels are analyzed using the nonlinear, non-asymmetric logistic STAR model in order to determine price transmission structure. A price threshold parameter is used so that price transmission levels can vary, thereby allowing an examination of the efficacy with which the hog and broiler price stabilization mechanisms take effect.Broiler industry, Pork industry, Price stabilization, Domestic marketing system, Smooth transition autoregressive (STAR) methodology

Plasmonic edge states: an electrostatic eigenmode description

We consider periodic arrangements of metal nanostructures and study the effect of periodicity on the localised surface plasmon resonance of the structures within an electrostatic eigenmode approximation. We show that within this limit, the collective surface plasmon resonances of the periodic structures can be expressed in terms of superpositions of the eigenmodes of uncoupled nanostructures that exhibit a standing--wave character delocalised across the entire periodic structure. The formalism derived successfully enables the design and accounts for the observation of plasmonic edge-states in periodic structures