Pedestrian Flow Simulation Validation and Verification Techniques

For the verification and validation of microscopic simulation models of pedestrian flow, we have performed experiments for different kind of facilities and sites where most conflicts and congestion happens e.g. corridors, narrow passages, and crosswalks. The validity of the model should compare the experimental conditions and simulation results with video recording carried out in the same condition like in real life e.g. pedestrian flux and density distributions. The strategy in this technique is to achieve a certain amount of accuracy required in the simulation model. This method is good at detecting the critical points in the pedestrians walking areas. For the calibration of suitable models we use the results obtained from analyzing the video recordings in Hajj 2009 and these results can be used to check the design sections of pedestrian facilities and exits. As practical examples, we present the simulation of pilgrim streams on the Jamarat bridge. The objectives of this study are twofold: first, to show through verification and validation that simulation tools can be used to reproduce realistic scenarios, and second, gather data for accurate predictions for designers and decision makers.Comment: 19 pages, 10 figure

Internet Auctions: Description, Bidders' Profiles and Implications

The increasing quantity of items bough and sold over the internet led to the success of internet auctions, to the introduction of new auction rules and the creation of new businesses and merger among existing ones. In this paper, we present a description of existing internet auction rules and typical profile of consumers who use them. We found that bidders are most likely located in the U.S., have some internet experience and skills and that they belong to the 26-50 years old age group. We also discuss the implication of online auctions on resource allocation.Internet Auctions, Online Auctions

Bullish-Bearish strategies of trading: A non-linear equilibrium.

In this paper, we study a financial market where risk neutral traders are endowed with a signal which is perfectly revealing of the direction (but not the exact amount) of the liquidation value of a normally distributed risky asset. This type of information is known as bullish or bearish. When the signal is positive (negative) the traders buy (sell) the asset. This type of information is different with the type of information which is classically considered in the literature where informed traders are endowed with a perfect or a noisy signal. In this model, since the optimal trading strategy is not linear, the pricing schedule is also a non-linear function of the volumes. The main results are the following i) the price function is a non-linear Sigmo¨ıd-shaped function. ii) A monopolistic bullish-bearish type trader makes nearly thirty six percent of the profits she would have made with a perfect signal in a linear model `a la Kyle (1985). iii) In the presence of competition, the market reveals his private information quicker than in a noisy informed strategic oligopoly. Moreover, liquidity is no longer a monotonic increasing function of the number of competitors

Semi-Parametric Indirect Inference

We develop in this paper a generalization of the Indirect Inference (II) to semi-parametric settings and termed Semi-parametric Indirect Inference (SII). We introduce a new notion of Partial Encompassing which lays the emphasis on Pseudo True Values of Interest. The main difference with the older notion of encompassing is that some components of the pseudo-true value of interest associated with the structural parameters do correspond to true unknown values. This enables us to produce a theory of robust estimation despite mis-specifications in the structural model being used as a simulator. We also provide the asymptotic probability distributions of our SII estimators as well as Wald Encompassing Tests (WET) and advocate the use of Hausman type tests on the required assumptions for the consistency of the SII estimators. We illustrate our theory with examples based on semi-parametric stochastic volatility models.Indirect inference, partial encompassing, pseudo-true value of interest, structural models, instrumental models, Wald encompassing tests.