The impact of the new airport of Athens on the land values of Eastern Attica

The analysis of the value of the area around "Eleftherios Venizelos", the new airport in Greater Athens area has been based on a survey of the international experience and followed by a quantitative data analysis. The figures of the database come from the Objective System of Assessment (O.S.A.) as well as the Relative Price System of the Local Revenue Offices (R.P.S.R.O.). The data was analysed according to the hierarchical tree method and there has been a detailed reference to the restrictions and the conditions of the data use. The analysis has been at a horizontal level, that is, we have tried to interpret the increasing decline between the O.S.A. or the R.P.S.R.O. prices and the real prices of land The ranking system has been based on the functionality of the specific areas. The analysis has been at a vertical level too, that is, a year by year analysis of the built-up areas which have been grouped geographically. These built-up areas come under the O.S.A. and R.P.S.R.O. systems. The analysis also, determines the perspective on the land use pattern of the study area.

A near-optimal approximation algorithm for Asymmetric TSP on embedded graphs

We present a near-optimal polynomial-time approximation algorithm for the asymmetric traveling salesman problem for graphs of bounded orientable or non-orientable genus. Our algorithm achieves an approximation factor of O(f(g)) on graphs with genus g, where f(n) is the best approximation factor achievable in polynomial time on arbitrary n-vertex graphs. In particular, the O(log(n)/loglog(n))-approximation algorithm for general graphs by Asadpour et al. [SODA 2010] immediately implies an O(log(g)/loglog(g))-approximation algorithm for genus-g graphs. Our result improves the O(sqrt(g)*log(g))-approximation algorithm of Oveis Gharan and Saberi [SODA 2011], which applies only to graphs with orientable genus g; ours is the first approximation algorithm for graphs with bounded non-orientable genus. Moreover, using recent progress on approximating the genus of a graph, our O(log(g) / loglog(g))-approximation can be implemented even without an embedding when the input graph has bounded degree. In contrast, the O(sqrt(g)*log(g))-approximation algorithm of Oveis Gharan and Saberi requires a genus-g embedding as part of the input. Finally, our techniques lead to a O(1)-approximation algorithm for ATSP on graphs of genus g, with running time 2^O(g)*n^O(1)

Minimum d-dimensional arrangement with fixed points

In the Minimum $d$-Dimensional Arrangement Problem (d-dimAP) we are given a graph with edge weights, and the goal is to find a 1-1 map of the vertices into $\mathbb{Z}^d$ (for some fixed dimension $d\geq 1$) minimizing the total weighted stretch of the edges. This problem arises in VLSI placement and chip design. Motivated by these applications, we consider a generalization of d-dimAP, where the positions of some of the vertices (pins) is fixed and specified as part of the input. We are asked to extend this partial map to a map of all the vertices, again minimizing the weighted stretch of edges. This generalization, which we refer to as d-dimAP+, arises naturally in these application domains (since it can capture blocked-off parts of the board, or the requirement of power-carrying pins to be in certain locations, etc.). Perhaps surprisingly, very little is known about this problem from an approximation viewpoint. For dimension $d=2$, we obtain an $O(k^{1/2} \cdot \log n)$-approximation algorithm, based on a strengthening of the spreading-metric LP for 2-dimAP. The integrality gap for this LP is shown to be $\Omega(k^{1/4})$. We also show that it is NP-hard to approximate 2-dimAP+ within a factor better than \Omega(k^{1/4-\eps}). We also consider a (conceptually harder, but practically even more interesting) variant of 2-dimAP+, where the target space is the grid $\mathbb{Z}_{\sqrt{n}} \times \mathbb{Z}_{\sqrt{n}}$, instead of the entire integer lattice $\mathbb{Z}^2$. For this problem, we obtain a $O(k \cdot \log^2{n})$-approximation using the same LP relaxation. We complement this upper bound by showing an integrality gap of $\Omega(k^{1/2})$, and an \Omega(k^{1/2-\eps})-inapproximability result. Our results naturally extend to the case of arbitrary fixed target dimension $d\geq 1$

Fiscal Policy in a Monetary Union in the Presence of Uncertainty about the Central Bank Preferences

In this paper, we examine the link between political transparency of a common central bank (CCB) and decentralized supply-side fiscal policies in a monetary union. We find that the opacity of a conservative CCB has a restrictive effect on national fiscal policies since each government internalizes the influence of its actions on the common monetary policy and thus reinforces the disciplinary effect of institutional constraints such as the Stability and Growth Pact on national fiscal authorities. However, more opacity could imply higher inflation and unemployment when the union is large enough and induce higher inflation and output-gap variability. An enlargement of the union incites national governments to increase tax rate, and weakens the disciplinary effects of opacity on member countries if fiscal policymaking is relatively decentralized and the CCB quite conservative. It induces an increase in the level of inflation and unemployment, and could increase inflation and output-gap variability.central bank transparency; supply-side fiscal policy; monetary union