Purchasing Power Parity among developing countries and their trade-partners. Evidence from selected CEECs and Implications for their membership of EU.

The purpose of the paper is twofold. Firstly, we test the validity of the PPP hypothesis for selected CEEC (Czech Republic; Hungary; Poland and Slovak Republic). Secondly, we attempt to define those countries’ trade linkages between Euro Area; US and the rest of the world. By applying both univariate unit root and a multivariate cointegration test, we find stronger evidence of PPP from the latter test. Moreover, any failure to accept PPP cannot be attributed to structural breaks, apart from one case (between Czech Republic and EU). In overall, there is evidence of strong-form PPP in 6 out of the 8 cases, while for the rest two, weak-form PPP is accepted. Thus, we confirm PPP as a long run equilibrium baseline for these exchange rates per EURO. Furthermore, the fact that PPP holds between these countries and Euro Area indicates absence of trade frictions and other barriers. The implied well-developed trade relations are consistent with those countries’ entry into EMU.PPP, Unit Root, Structural Breaks, Cointegration, Developing Countries

Fundamentals of Large Sensor Networks: Connectivity, Capacity, Clocks and Computation

Sensor networks potentially feature large numbers of nodes that can sense their environment over time, communicate with each other over a wireless network, and process information. They differ from data networks in that the network as a whole may be designed for a specific application. We study the theoretical foundations of such large scale sensor networks, addressing four fundamental issues- connectivity, capacity, clocks and function computation. To begin with, a sensor network must be connected so that information can indeed be exchanged between nodes. The connectivity graph of an ad-hoc network is modeled as a random graph and the critical range for asymptotic connectivity is determined, as well as the critical number of neighbors that a node needs to connect to. Next, given connectivity, we address the issue of how much data can be transported over the sensor network. We present fundamental bounds on capacity under several models, as well as architectural implications for how wireless communication should be organized. Temporal information is important both for the applications of sensor networks as well as their operation.We present fundamental bounds on the synchronizability of clocks in networks, and also present and analyze algorithms for clock synchronization. Finally we turn to the issue of gathering relevant information, that sensor networks are designed to do. One needs to study optimal strategies for in-network aggregation of data, in order to reliably compute a composite function of sensor measurements, as well as the complexity of doing so. We address the issue of how such computation can be performed efficiently in a sensor network and the algorithms for doing so, for some classes of functions.Comment: 10 pages, 3 figures, Submitted to the Proceedings of the IEE

Asymmetric Volatility Spillovers between Stock Market and Real Activity: Evidence from the UK and the US

This paper examines the short-run dynamic relationships between stock market and real activity, within a country, for the UK and the US. The Cross Correlation Function testing procedure is applied to test for causality in mean and in variance between the stock market and the real economic sector. Besides variance causation, volatility spillover effects are examined through the multivariate specification form of the Exponential GARCH model. There is evidence of significant reciprocal volatility spillovers between the two sectors within a country, implying stronger interdependencies in the UK rather than in the US and asymmetric behavior only in the case of the UK.Stock market, Real activity, Volatility spillovers, UK, US