Soundly Handling Static Fields: Issues, Semantics and Analysis

Although in most cases class initialization works as expected, some static fields may be read before being initialized, despite being initialized in their corresponding class initializer. We propose an analysis which compute, for each program point, the set of static fields that must have been initialized and discuss its soundness. We show that such an analysis can be directly applied to identify the static fields that may be read before being initialized and to improve the precision while preserving the soundness of a null-pointer analysis.Comment: Proceedings of the Fourth Workshop on Bytecode Semantics, Verification, Analysis and Transformation (BYTECODE 2009

Hitting times for Gaussian processes

We establish a general formula for the Laplace transform of the hitting times of a Gaussian process. Some consequences are derived, and particular cases like the fractional Brownian motion are discussed.Comment: Published in at http://dx.doi.org/10.1214/009117907000000132 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

The three different phases in the dynamics of chemical reaction networks and their relationship to cancer

We investigate the catalytic reactions model used in cell modeling. The reaction kinetic is defined through the energies of different species of molecules following random independent distribution. The related statistical physics model has three phases and these three phases emerged in the dynamics: fast dynamics phase, slow dynamic phase and ultra-slow dynamic phase. The phenomenon we found is a rather general, does not depend on the details of the model. We assume as a hypothesis that the transition between these phases (glassiness degrees) is related to cancer. The imbalance in the rate of processes between key aspects of the cell (gene regulation, protein-protein interaction, metabolical networks) creates a change in the fine tuning between these key aspects, affects the logics of the cell and initiates cancer. It is probable that cancer is a change of phase resulting from increased and deregulated metabolic reactions.Comment: 5 pages, 2 figures, EPL, in pres

An Empirical Analysis of Income Convergence in the European Union

In this paper, we investigate the convergence process within the European Union (27 countries). More particularly, we study the convergence process of the new entrants from Central and Eastern Europe and of the 15 Western countries between 1990 and 2007. Applying a panel approach to the convergence equation derived by Mankiw et al. (1992) from the Solow model, we highlight the existence of heterogeneity in the European Union and show that new entrants and former members of the European Union can be seen as belonging to significantly differ ent groups of convergence. The existence of heterogeneity in the European Union or the Eurozone might affect their stability as the recent Greece’s sovereign debt crisis illustrates it.

Waves and instabilities in rotating free surface flows

The stability properties of the rotating free surface flow in a cylindrical container is studied using a global stability approach, considering succesively three models. For the case of solid body rotation (Newton’s bucket), all eigenmodes are found to be stable, and are classified into three families : gravity waves, singular inertial modes, and Rossby waves. For the case of a potential flow, an instability is found. The mechanism is explained as a resonance between gravity waves and centrifugal waves, and is thought to be at the origin of the ”rotating polygon instability” observed in experiments where the flow is driven by rotation of the bottom plate (see [9]). Finally, we give some preliminary results concerning a third model : the Rankine vortex

On the importance of prismatic/basal interfaces in the growth of (-1012) twins in hexagonal close-packed crystals

The growth process of of (-1012) twins is studied in Magnesium using atomistic simulations. Two twin seeds are considered and both cases, a specific interface, which places face-to-face prismatic and basal planes, plays an important role. This interface has a low energy corresponding to a cusp in the orientation-dependent interface energy of a twinned bicrystal. This interface appears in several published twin structures and for instance accommodates the large deviations of twin interfaces from (-1012) planes reported recently [Zhang et al., Scr. Mater. 67 (2012) 862].Comment: 11 pages, 4 figures, submitted to Scripta Materiali

A surplus and welfare analysis of asymmetric regulation

Some European regulators have decided to force competition in their nationalmarkets. They have decided to go beyond the second directive and apply asymmetric regulation. Gas release programs and market shares constraints are the two asymmetric decisions imposed to incumbents. When a regulator imposes a gas release program to an incumbent, this operator is compelled to release quantities of its long term contracts to its competitor. In this paper, we will focus on gas release and its impact on welfare, consumer surplus and on the level of released quantities set by regulators. The aim of a gas release program is to give access to natural gas to competitors. They become actives on the market and are in competition with the incumbent. These programs are time limited. They only help competitors in expecting the development of hubs or new investments in importation infrastructures. If competitors want to stay active after the program, they may find others supply sources to increase security of supply. The gas release can induce Raising Rival's Costs or "Self-Sabotage" strategies. We use a Cournot model with capacity constraints to answer two questions. First, we will study the impact of these strategies on consumer surplus and welfare. We will show that there are no impact on consumer surplus but the welfare decreases. The gas release program introduces a transfer of profit between competitor and incumbent, reduces welfare because of the increase in costs of supply, but has no impact on total consumed quantities. Then, we will suppose that the regulator is setting released quantities maximising welfare. Gas release price is often based on costs plus a bid or a fixed premium. Quantities are set with a less obvious process. We will demonstrate that the regulator must set released quantities :- that would not be so high if incumbent's supplies are small to avoid Self- Sabotage or RRC strategies ;- as a function of incumbent's supplies if they are in intermediate values to avoid strategies seen above and to optimise quantities sold on the market ;- at a sufficient level to let the two operators playing their Cournot best reply function. Finally, we will conclude that the regulator can avoid RRC or Self-Sabotage strategies in maximising the welfare when it decides gas released quantities. Gathering from empirical studies, these quantities should not be so high in order to let a significant difference between the capacities of both competitor and incumbent to avoid collusive behaviours.Energy market ; Gas release ; Regulation ; Optimal released quantities ; Efficiency ; Welfare

The impact of asymmetric regulation on surplus and welfare : the case of gas release programmes

Some European regulators have decided to force competition in their nationalmarkets. They have decided to go beyond the second directive and apply asymmetric regulation. Gas release programs and market shares constraints are the two asymmetric decisions imposed to incumbents. When a regulator imposes a gas release program to an incumbent, this operator is compelled to release quantities of its long term contracts to its competitor. In this paper, we will focus on gas release and its impact on welfare, consumer surplus and on the level of released quantities set by regulators. The aim of a gas release program is to give access to natural gas to competitors. They become actives on the market and are in competition with the incumbent. These programs are time limited. They only help competitors in expecting the development of hubs or new investments in importation infrastructures. If competitors want to stay active after the program, they may find others supply sources to increase security of supply. The gas release can induce Raising Rival's Costs or “Self-Sabotage” strategies. We use a Cournot model with capacity constraints to answer two questions. First, we will study the impact of these strategies on consumer surplus and welfare. We will show that there are no impact on consumer surplus but the welfare decreases. The gas release program introduces a transfer of profit between competitor and incumbent, reduces welfare because of the increase in costs of supply, but has no impact on total consumed quantities. Then, we will suppose that the regulator is setting released quantities maximising welfare. Gas release price is often based on costs plus a bid or a fixed premium. Quantities are set with a less obvious process. We will demonstrate that the regulator must set released quantities : - that would not be so high if incumbent's supplies are small to avoid Self- Sabotage or RRC strategies; - as a function of incumbent's supplies if they are in intermediate values to avoid strategies seen above and to optimise quantities sold on the market; - at a sufficient level to let the two operators playing their Cournot best reply function. Finally, we will conclude that the regulator can avoid RRC or Self-Sabotage strategies in maximising the welfare when it decides gas released quantities. Gathering from empirical studies, these quantities should not be so high in order to let a significant difference between the capacities of both competitor and incumbent to avoid collusive behaviours.REGULATION ; MARCHE INTERIEUR ; GAZ NATUREL ; MARCHE CONCURRENTIEL ; GAS RELEASE