Nominal Rigidities and The Real Effects of Monetary Policy in a Structural VAR Model

The paper proposes an empirical VAR for the UK open economy in order to measure the effects of monetary policy shocks from 1981 to 2003. The identification of the VAR structure is based on short-run restrictions that are consistent with the general implications of a New Keynesian model. The identification scheme used in the paper is successful in identifying monetary policy shocks and solving the puzzles and anomalies regarding the effects of monetary policy shocks. The estimated dynamic impulse responses and the forecast error variance decompositions show a consistency with the New Keynesian approach and other available theories.Structural VAR; Nominal Rigidities; Monetary Policy Shocks; New Keynesian Theory

Trade-off between trade and the environment : a study from Vietnam

A summary of EEPSEA research report 2008-RR5 "The Impact of Trade liberalization and Industrial Pollution: Empirical Evidence from Vietriam" by Pham Thai Hung, Bui Anh Tuan and Nguyen The Chinh, c/o National Economics University

シールド工法におけるセグメント設計法の境界条件に関する研究

国立大学法人長岡技術科学大

Exploration efficace de l'espace d'état pour les programmes distribués asynchrones: Adaptation de l’UDPOR aux programes MPI.

Distributed message passing applications are in the mainstream of information technology since they exploit the power of parallel computer systems to produce higher performance. Designing distributed programs remains challenging because developers have to reason about concurrency, non-determinism, data distribution… that are main characteristics of distributed programs. Besides, it is virtually impossible to ensure the correctness of such programs via classical testing approaches since one may never successfully reach the execution that leads to unwanted behaviors in the programs. There is thus a need for more powerful verification techniques. Model-checking is one of the formal methods that allows to verify automatically and effectively some properties on models of computer systems by exploring all possible behaviors (states and transitions) of the system model. However, state spaces increase exponentially with the number of concurrent processes, leading to “state space explosion”.Unfolding-based Dynamic Partial Order Reduction (UDPOR) is a recent technique mixing Dynamic Partial Order Reduction (DPOR) with concepts of concurrency theory such as unfoldings to efficiently mitigate state space explosion in model-checking of concurrent programs. It is optimal in the sense that each Mazurkiewicz trace, i.e. a class of interleavings equivalent by commuting adjacent independent actions, is explored exactly once. And it is applicable to running programs, not only models of programs.The thesis aims at adapting UDPOR to verify asynchronous distributed programs (e.g. MPI programs) in the setting of the SIMGRID simulator of distributed applications. To do so, an abstract programming model of asynchronous distributed programs is defined and formalized in the TLA+ language, allowing to precisely define an independence relation, a main ingredient of the concurrency semantics. Then, the adaptation of UDPOR, involving the construction of an unfolding, is made efficient by a precise analysis of dependencies in the programming model, allowing efficient computations of usually costly operation. A prototype implementation of UDPOR adapted to distributed asynchronous programs has been developed, giving promising experimental results on a significant set of benchmarks.Distributed message passing applications are in the mainstream of information technology since they exploit the power of parallel computer systems to produce higher performance. Designing distributed programs remains challenging because developers have to reason about concurrency, non-determinism, data distribution… that are main characteristics of distributed programs. Besides, it is virtually impossible to ensure the correctness of such programs via classical testing approaches since one may never successfully reach the execution that leads to unwanted behaviors in the programs. There is thus a need for more powerful verification techniques. Model-checking is one of the formal methods that allows to verify automatically and effectively some properties on models of computer systems by exploring all possible behaviors (states and transitions) of the system model. However, state spaces increase exponentially with the number of concurrent processes, leading to “state space explosion”.Unfolding-based Dynamic Partial Order Reduction (UDPOR) is a recent technique mixing Dynamic Partial Order Reduction (DPOR) with concepts of concurrency theory such as unfoldings to efficiently mitigate state space explosion in model-checking of concurrent programs. It is optimal in the sense that each Mazurkiewicz trace, i.e. a class of interleavings equivalent by commuting adjacent independent actions, is explored exactly once. And it is applicable to running programs, not only models of programs.The thesis aims at adapting UDPOR to verify asynchronous distributed programs (e.g. MPI programs) in the setting of the SIMGRID simulator of distributed applications. To do so, an abstract programming model of asynchronous distributed programs is defined and formalized in the TLA+ language, allowing to precisely define an independence relation, a main ingredient of the concurrency semantics. Then, the adaptation of UDPOR, involving the construction of an unfolding, is made efficient by a precise analysis of dependencies in the programming model, allowing efficient computations of usually costly operation. A prototype implementation of UDPOR adapted to distributed asynchronous programs has been developed, giving promising experimental results on a significant set of benchmarks

Linking first occurrence polynomials over F_p by Steenrod operations

This paper provides analogues of the results of [G.Walker and R.M.W. Wood, Linking first occurrence polynomials over F_2 by Steenrod operations, J. Algebra 246 (2001), 739--760] for odd primes p. It is proved that for certain irreducible representations L(lambda) of the full matrix semigroup M_n(F_p), the first occurrence of L(lambda) as a composition factor in the polynomial algebra P=F_p[x_1,...,x_n] is linked by a Steenrod operation to the first occurrence of L(lambda) as a submodule in P. This operation is given explicitly as the image of an admissible monomial in the Steenrod algebra A_p under the canonical anti-automorphism chi . The first occurrences of both kinds are also linked to higher degree occurrences of L(lambda) by elements of the Milnor basis of A_p.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-27.abs.htm