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

Tracking Individual Targets in High Density Crowd Scenes Analysis of a Video Recording in Hajj 2009

In this paper we present a number of methods (manual, semi-automatic and automatic) for tracking individual targets in high density crowd scenes where thousand of people are gathered. The necessary data about the motion of individuals and a lot of other physical information can be extracted from consecutive image sequences in different ways, including optical flow and block motion estimation. One of the famous methods for tracking moving objects is the block matching method. This way to estimate subject motion requires the specification of a comparison window which determines the scale of the estimate. In this work we present a real-time method for pedestrian recognition and tracking in sequences of high resolution images obtained by a stationary (high definition) camera located in different places on the Haram mosque in Mecca. The objective is to estimate pedestrian velocities as a function of the local density.The resulting data of tracking moving pedestrians based on video sequences are presented in the following section. Through the evaluated system the spatio-temporal coordinates of each pedestrian during the Tawaf ritual are established. The pilgrim velocities as function of the local densities in the Mataf area (Haram Mosque Mecca) are illustrated and very precisely documented.Comment: 20 pages, 17 figures, correction of some reference

Simulation of high density pedestrian flow : a microscopic model

In recent years, modelling crowd and evacuation dynamics has become very important, with increasing huge numbers of people gathering around the world for many reasons and events. The fact that our global population grows dramatically every year and the current public transport systems are able to transport large amounts of people heightens the risk of crowd panic or crush. Pedestrian models are based on macroscopic or microscopic behaviour. In this paper, we are interested in developing models that can be used for evacuation control strategies. This model will be based on microscopic pedestrian simulation models, and its evolution and design requires a lot of information and data. The people stream will be simulated, based on mathematical models derived from empirical data about pedestrian flows. This model is developed from image data bases, so called empirical data, taken from a video camera or data obtained using human detectors. We consider the individuals as autonomous particles interacting through social and physical forces, which is an approach that has been used to simulate crowd behaviour. The target of this work is to describe a comprehensive approach to model a huge number of pedestrians and to simulate high density crowd behaviour in overcrowding places, e.g. sport, concert and pilgrimage places, and to assist engineering in the resolution of complicated problems through integrating a number of models from different research domains

List of parameters influencing the pedestrian movement and pedestrian database

In this paper we present a list of factors influencing the pedestrian behaviour in different situations and conditions. In crowd simulation input we must consider at least two simulation conditions. The first is the normal condition and the second is the emergency condition or panic situation. In panic situations most parameters will be changed and the time factor becomes very important. Both emotion and personality clearly have a strong and considerable impact on individual behaviours in such situations. However, most existing approaches in their attempt to model the behaviour of individuals and for guiding an agent to interact with its environment and other agents, consider the individual as an autonomous agent or autonomous particle that obeys some human-like behaviour modules such as locomotion, perception, and decision making. Other models treat the crowd as a collection of homogeneous particles interacting through physical forces. Today with the enormous knowledge development in computer science, many models try to improve themselves. There seems to be an evolution in crowd simulation to model each individual as some kind of intelligent agent with attempts to incorporate more and more social and psychological factors into the agent behaviour model. However, to reproduce more realistic simulation behaviours many factors and attributes influencing pedestrians must be considered. The actual shortcoming of the existing models is the absence of modelling the social group process and its impact on human behaviour. One way to gain a better understanding of human behaviour in this area is to enrich the tools available for planning, such as pedestrian micro simulation in case of panic situations and emergency conditions. In this work a pedestrian database called PedGUI containing a lot of information about pedestrians is developed, this have a significant impact on the simulation input at least two mean pedestrian characteristics like age and gender can be considered

Reperfusion therapy in renal dysfunction patients presenting with STEMI: Which is better in the Tunisian context?

BackgroundPatients with renal insufficiency experience worse prognosis after STEMI. Current guidelines do not clearly draw specific strategies for renal dysfunction (RD) patients, and most clinical trials exclude them from the study population.Aim of the studyTo compare primary PCI (PPCI) and thrombolysis (using Strepokinase) results as well as in-hospital mortality after successful reperfusion between patients with or without RD.MethodsFrom January 1995 to October 2011, 1388 patients admitted for STEMI were enrolled in the MIRAMI (MonastIR’s Acute Myocardial Infarction) registry. Two reperfusion groups were identified: PPCI (315 patients) and thrombolysis (379 patients). Patients who underwent rescue PCI were excluded. Due to lacking clearance data, we used a serum creatinine level >130μmol/l to define RD patients. We compared in each reperfusion group: (1) The success of revascularization (TIMI III flow restoring with <20% residual stenosis after PPCI, pain relief with ST regression >50% 60min after thrombolysis) and (2) the in-hospital mortality rate after reperfusion success between the RD patients (RD+) and normal renal function patients (RD−).ResultsNinety patients (13%) had RD, 50% of which underwent PPCI, and 50% received thrombolytics. Among RD+ and RD- groups, baseline characteristics were similar between the two reperfusion groups.In the PPCI group, although TIMI flow was similar before angioplasty (p=0.82), TIMI III restoring was significantly lower in the RD+ group (78.6% vs 91.8%, p=0.013). Suboptimal result was also higher in the RD+ group (13.6% vs 2.7%, p<0.001), but ST regression after TIMI III achievement was similar in the 2 groups (p=0.43) reflecting probably no microvascular damage.In the thrombolysis group, successful reperfusion was also significantly lower when RD exists (58% vs 74%, p=0.03).After successful reperfusion, in-hospital mortality is higher among RD+ patients in the PPCI group (33.3% vs 4.3%, p<0.001), whereas it is similar after successful thrombolysis (2.6% vs 0%, p=0.42).ConclusionRD reduces either PPCI or thrombolysis success, with no proven microvascular damage after PPCI. In-hospital prognosis is however worse in RD group only after successful PPCI, but not after successful Streptokinase thrombolysis

Physiological and Biochemical behaviours and antioxidant response of Helianthus annuus under Lanthanum and Cerium Stress

The continuous progress of global manufacturing and anthropogenic activities has resulted in excessive environmental metallic pollution, particularly with rare earth elements (REEs) which have become a prevalent issue of global concern due to their high toxicity and widespread existence. REEs-contaminated soils could ruin agriculture by inducing plant physiology disturbances in various crops that are considered the principal link of the human food chain. The main purpose of the present work is to assess the phytotoxicity of two light REEs, lanthanum (La) and cerium (Ce), in Helianthus annuus after 14 days of exposure to different concentrations of La and Ce (0, 1, 2.5, 5, and 10 µM). Plants showed different variations in shoot and root lengths at the end of the trial period. The accumulation of photosynthetic pigments, such as chlorophylls and carotenoids, as well as the photosynthetic efficiency, the non-photochemical quenching, the photosynthetically active radiation, and the electron transport rate, increased in the two REE treatments. Hydrogen peroxide significantly increased in all applied concentrations of La and Ce. A significant increase in malondialdehyde content was noticed only when plants were exposed to 2.5 µM La and 10 µM Ce. Results also demonstrated that La and Ce induced an increase in the activity of superoxide dismutase, peroxidase, and catalase (only the highest concentration of La decreased catalase activity). The exposure to different REE concentrations induced the accumulation of La and Ce in the plants, mainly in roots. Helianthus annuus showed an effective resistance behaviour facing La- and Ce-induced stresses

057 A simple prediction score for significant renal artery stenosis in patients with coronary artery disease

BackgroundRenal artery stenosis (RAS) is a strong independent predictor of mortality in patients (pts) with coronary artery disease (CAD).Aim of studyTo develop and validate a score predicting RAS in patients with CAD.MethodsThree hundred consecutive pts (50 females) with significant CAD underwent abdominal aortography following coronary angiography to screen for significant RAS defined as luminal narrowing of > 50%. Univariate and multivariate analyses were performed comparing pts with and without RAS. Significant factors associated with RAS were included in constructing a score that predicts RAS.The score was internally validated in pts randomly selected from the entire study group (validation group; n=103), using ROC curves and the Hosmer-Lemeshow goodness-of-fit test.ResultsTwenty-seven pts (9%) had a significant RAS. Univariate predictors of significant RAS were: age > 65 years (OR=4.5, p < 0.0001), hypertension (OR=3.6, p=0.001), and female gender (OR=3.6, p=0.015). We found a tendency of more prevalent renal insufficiency (37.1% vs. 21.5%; p=0.05) and the presence of 2 or more significant CAD lesions (70.4% vs. 50.9%; p=0.05) in pts with RAS.Multivariate analysis showed that age > 65 years (OR=4.1%, 95% CI=1.6-10.3, p=0.003) and hypertension (OR=3.1, 95% CI=1.2-7.7, p=0.015) were independent predictors of RAS. The ranged from 0 to 7: 2 points for age > 65 years and hypertension 1 point for female gender, renal insufficiency, and > 3-vessel disease). Internal validation showed a good performance (ROC curve = 0.79 and Chi2 Lemeshow = 3.45). For a score < 2, the negative predictive value is 98%. Applying this criteria, 48.3% of our population would not require systematic abdominal angiography.ConclusionThe performance of our predictive score was good, and significant reduction in the need to perform systematic abdominal aortography could be expected with the use of this score

Single Crystal X-Ray Structural Investigation of Alluaudite Related Monophosphate Na2FeMn2(PO4)3

The compound Na2FeMn2(PO4)3 has been successfully isolated with the alluaudite structural type. Accurate single crystal X-ray diffraction has allowed solving the structure with reliability factors of R1 and Rw equal to 0.0322 and 0.0790 respectively. It was found that the symmetry is monoclinic with a space group of C2/c and lattice parameters: a = 12.180(2) Å, b = 12.660(2) Å, c = 6.500(2) Å, B = 114.528(3)(°), unit cell volume = 911.8(3) Å3, Z = 8 and dcal.=3.618 g.cm-3. Three-dimensional network is formed by the [MnO6] octahedra linked in pairs to form Mn-based octahedral dimers: ([Mn2O10]). Each dimer shares six vertices with six tetrahedra [P(2)O4] to form sheets within the plane (100). The latter are connected by tetrahedra [P(1)O4] delimiting cages and tunnels which house either Fe3+ or Na+ cations. Each [FeO6] octahedron is linked to two [Mn2O10] dimers belonging to two adjacent sheets to form mixed Fe-Mn chains of the type: - Fe3+ - Mn2+ - Mn2+ - Fe3+ - Mn2+ - Mn2+ - Fe3+ - ..., running along the direction [101]