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Time Paths (time + paths)

Distribution by Scientific Domains

Business, Economics, Finance and Accounting	50%

Selected Abstracts

Learning and Noisy Equilibrium Behavior in an Experimental Study of Imperfect Price Competition*

INTERNATIONAL ECONOMIC REVIEW, Issue 3 2002
C. Monica Capra
We consider a duopoly pricing game with a unique Bertrand,Nashequilibrium. The high-price firm has a nonvanishing market share, however, and intuition suggests that observed prices may be positively related to this market share. This relationship is implied by a model in which players make noisy (logit) best responses to expected payoff differences. The resulting logit equilibrium model was used to design an experiment in which the high-price firm's market share varies. The model accurately predicts the final-period price averages. A naive learning model predicts the observed differences in the time paths of average prices. [source]

Parallel Algorithms for Dynamic Shortest Path Problems

INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 3 2002
Ismail Chabini
The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of shortest path problems in dynamic networks. Recently, a sequential algorithm was developed to compute shortest paths in discrete time dynamic networks from all nodes and all departure times to one destination node. The algorithm is known as algorithm DOT and has an optimal worst-case running-time complexity. This implies that no algorithm with a better worst-case computational complexity can be discovered. Consequently, in order to derive algorithms to solve all-to-one shortest path problems in dynamic networks, one would need to explore avenues other than the design of sequential solution algorithms only. The use of commercially-available high-performance computing platforms to develop parallel implementations of sequential algorithms is an example of such avenue. This paper reports on the design, implementation, and computational testing of parallel dynamic shortest path algorithms. We develop two shared-memory and two message-passing dynamic shortest path algorithm implementations, which are derived from algorithm DOT using the following parallelization strategies: decomposition by destination and decomposition by transportation network topology. The algorithms are coded using two types of parallel computing environments: a message-passing environment based on the parallel virtual machine (PVM) library and a multi-threading environment based on the SUN Microsystems Multi-Threads (MT) library. We also develop a time-based parallel version of algorithm DOT for the case of minimum time paths in FIFO networks, and a theoretical parallelization of algorithm DOT on an ,ideal' theoretical parallel machine. Performances of the implementations are analyzed and evaluated using large transportation networks, and two types of parallel computing platforms: a distributed network of Unix workstations and a SUN shared-memory machine containing eight processors. Satisfactory speed-ups in the running time of sequential algorithms are achieved, in particular for shared-memory machines. Numerical results indicate that shared-memory computers constitute the most appropriate type of parallel computing platforms for the computation of dynamic shortest paths for real-time ITS applications. [source]

Two contrasted P,T,time paths of coronitic metanorites of the French Massif Central: are reaction textures reliable guides to metamorphic histories?

JOURNAL OF METAMORPHIC GEOLOGY, Issue 2 2005
C. NICOLLET
Abstract Metanorites from two eclogitized metagabbros of the Hercynian French Massif Central preserve coronitic textures of hornblende, garnet, quartz and/or kyanite produced at the expense of the primary magmatic assemblage orthopyroxene and plagioclase. Using a petrogenetic grid in the CFMASH system, two possible P,T evolutions for the origin of the coronas are evaluated. The sequence of reactions involving the formation of Hbl (,Ky) ± Grt and Qtz coronitic assemblages is consistent with an isobaric cooling at high pressure (c. 1,2 GPa) under hydrated conditions. However, this P,T path, inferred by using only petrographical observations, is inconsistent with the geochronological constraints: emplacement of the gabbro at 490 Ma and high-pressure metamorphism at 410 Ma. In order to reconcile petrographical observations with geochronological constraints, we propose a discontinuous two-stage evolution involving a change in water activity with time. (1) Emplacement and cooling of the norite at low pressure under anhydrous conditions, at 490 Ma. (2) During the Hercynian orogeny, the norite experienced an increase in pressure and temperature under fluid-present conditions. Adding water to the system implies a dramatic change in the petrogenetic grid topology, restricting the orthopyroxene,plagioclase assemblage only to high temperatures. Therefore, the breakdown of the unstable magmatic assemblage, through apparent retrograde reactions, occurred along the prograde P,T path which never crossed the equilibrium boundaries of these reactions. [source]

HOMEOWNERSHIP IN AN UNCERTAIN WORLD WITH SUBSTANTIAL TRANSACTION COSTS,

JOURNAL OF REGIONAL SCIENCE, Issue 5 2007
Margaret H. Smith
ABSTRACT This paper presents a dynamic model of residential real estate tenure decisions that takes into account the substantial transaction costs and the uncertain time paths of rents and prices. By temporarily postponing decisions, buyers and sellers obtain additional information and may avoid transactions that are costly to reverse. One implication is that the combination of high transaction costs and substantial uncertainty can create a large wedge between a household's reservation prices for buying and selling a home, which can explain why households do not switch back and forth between owning and renting as home prices fluctuate. [source]