Towards accelerated agent-based crowd simulation for Hajj and Umrah

There are many scientific applications ranging from weather prediction to oil and gas exploration that requires high-performance computing. It aids industries and researchers to enrich further their advancements. With the advent of general purpose computing over GPUs, most of the applications above are shifting towards High-Performance Computing (HPC). Agent-based crowd simulation is one of the candidates that requires high-performance computing. This type of application is used to predict crowd movement in highly congested areas. One of the most crucial scenarios in which this application can be used is to mimic the movement of the multi-cultural crowd performing Hajj and Umrah in Masjid Al-Haram, Makkah. Adequate performance for an agent-based crowd system is a common problem in computer science. While the existing event planning software, specifically for Hajj and Umrah, are unable to provide the required performance. The main reason is the increasing amount of autonomous pilgrims every year. In this paper, we propose a high performance agent-based crowd simulation that represents pilgrim movement during these rituals. The performance is achieved by parallelizing an open source steering library called OpenSteer using CUDA over GPU. By using our technique, event organizers will be able to simulate large crowds and will also be able to predict whether the developed event plan is viable or not. We have also discussed the architecture and implementation of this parallel Hajj simulation

Velocity-based modeling of physical interactions in dense crowds

We present an interactive algorithm to model physics-based interactions in dense crowds. Our approach is capable of modeling both physical forces and interactions between agents and obstacles, while also allowing the agents to anticipate and avoid upcoming collisions during local navigation. We combine velocity-based collision-avoidance algorithms with external physical forces. The overall formulation produces various effects of forces acting on agents and crowds, including balance recovery motion and force propagation through the crowd. We further extend our method to model more complex behaviors involving social and cultural rules. We use nite state machines to specify a series of behaviors and demonstrate our approach on many complex scenarios. Our algorithm can simulate a few thousand agents at interactive rates and can generate many emergent behaviors

GPU-based optimization of pilgrim simulation for hajj and umrah rituals

Tawaf ritual performed during Hajj and Umrah is one of the most unique, large-scale multi-cultural events in this modern day and age. Pilgrims from all over the world circumambulate around a stone cube structure called Ka'aba. Disasters at these types of events are inevitable due to erratic behaviours of pilgrims. This has prompted researchers to present several solutions to avoid such incidents. Agent-based simulations of a large number of pilgrims performing different the ritual can provide the solution to obviate such disasters that are either caused by mismanagement or because of irregular event plans. However, the problem arises due to limited parallelisation capabilities in existing models for concurrent execution of the agent-based simulation. This limitation decreases the efficiency by producing insufficient frames for simulating a large number of autonomous agents during Tawaf ritual. Therefore, it has become very necessary to provide a parallel simulation model that will improve the performance of pilgrims performing the crucial ritual of Tawaf in large numbers. To fill in this gap between large-scale agent-based simulation and navigational behaviours for pilgrim movement, an optimised parallel simulation software of agent-based crowd movement during the ritual of Tawaf is proposed here. The software comprises parallel behaviours for autonomous agents that utilise the inherent parallelism of Graphics Processing Units (GPU). In order to implement the simulation software, an optimized parallel model is proposed. This model is based on the agent-based architecture which comprises agents having a reactive design that responds to a fixed set of stimuli. An advantage of using agents is to provide artificial anomaly to generate heterogeneous movement of the crowd as opposed to a singular movement which is unrealistic. The purpose is to decrease the execution time of complex behaviour computation for each agent while simulating a large crowd of pilgrims at increased frames per second (fps). The implementation utilises CUDA (Compute Unified Device Architecture) platform for general purpose computing over GPU. It exploits the underlying data parallel capability of an existing library for steering behaviours, called OpenSteer. It has simpler behaviours that when combined together, produces more complex realistic behaviours. The data-independent nature of these agent-based behaviours makes it a very suitable candidate to be parallelised. After an in-depth review of previous studies on the simulation of Tawaf ritual, two key behaviours associated with pilgrim movement are considered for the new model. The parallel simulation is executed on three different high-performance configurations to determine the variation in different performance metrics. The parallel implementation achieved a considerable speedup in comparison to its sequential counterpart running on a single-threaded CPU. With the use of parallel behaviours, 100,000 pilgrims at 10 fps were simulated

Increased prevalence of methicillin-resistant Staphylococcus aureus nasal colonization in household contacts of children with community acquired disease

<p>Abstract</p> <p>Background</p> <p>To measure Methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) nasal colonization prevalence in household contacts of children with current community associated (CA)-MRSA infections (study group) in comparison with a group of household contacts of children without suspected <it>Staphylococcus aureus </it>infection (a control group).</p> <p>Methods</p> <p>This is a cross sectional study. Cultures of the anterior nares were taken. Relatedness of isolated strains was tested using pulse field gel electrophoresis (PFGE).</p> <p>Results</p> <p>The prevalence of MRSA colonization in the study group was significantly higher than in the control group (18/77 (23%) vs 3/77 (3.9%); p ≤ 0.001). The prevalence of SA colonization was 28/77 (36%) in the study group and 16/77 (21%) in the control group (p = 0.032). The prevalence of SA nasal colonization among patients was 6/24 (25%); one with methicillin-susceptible <it>S. aureus </it>(MSSA) and 5 with MRSA. In the study (patient) group, 14/24 (58%) families had at least one household member who was colonized with MRSA compared to 2/29 (6.9%) in the control group (p = 0.001). Of 69 total isolates tested by PFGE, 40 (58%) were related to USA300. Panton-Valetine leukocidin (PVL) genes were detected in 30/52 (58%) tested isolates. Among the families with ≥1 contact colonized with MRSA, similar PFGE profiles were found between the index patient and a contact in 10/14 families.</p> <p>Conclusions</p> <p>Prevalence of asymptomatic nasal carriage of MRSA is higher among household contacts of patients with CA-MRSA disease than control group. Decolonizing such carriers may help prevent recurrent CA-MRSA infections.</p

Impact of suction with nanoparticles aggregation and joule heating on unsteady MHD stagnation point flow of nanofluids over horizontal cylinder

Significance of study: Nanofluids with aggregation effects mediated by nanoparticles, like geothermal panels and crossflow heat exchangers, ignite new industrial interests. Polymer and conversion processes have transport phenomena in the stagnation zone that must be continuously improved to raise the process quality standard. Aim of study: Hence, the current computational study examines a TiO2−C2H6O2 nanofluid's unsteady stagnation-point flow performance via a shrinking horizontal cylinder. In addition, the effects of a magnetic field, joule-heating viscous dissipation, nanoparticles aggregation and mass suction on the boundary layer flow are reflected. Method: ology: The RK-IV with shooting method is applied to resolve the simplified mathematical model numerically in computing software MATHEMATICA. In certain circumstances, comparing the current and prior findings indicates good agreement with a relative error of around 0%. Findings: The implementation of a heat transfer operation may be improved by increasing suction settings. Unsteadiness, nanoparticle volume fraction, magnetic, curvature, and Eckert number (implies the operating Joule heating and viscous dissipation) all influence heat transfer rate. The velocity and temperature profiles both increase as the unsteadiness, magnetic field, and nanoparticle volume fraction parameters increase, whereas the curvature and suction parameters show the opposite behavior. When the values of the suction parameters were changed from 2.0 to 2.5 with φ = 0.01, the heat transfer rates rose by 4.751%. A comparison shows that the model with aggregation has a better velocity profile, while the model without aggregation has a better temperature profile

Significance of entropy generation and nanoparticle aggregation on stagnation point flow of nanofluid over stretching sheet with inclined Lorentz force

It is well established that adding a certain number of nanoparticles to a nanofluid improves its thermal conductivity. The cause of this remarkable development is as of yet unidentified. Therefore, knowing the kinematics of nanoparticle aggregation is essential for determining the correct thermal impact of nanoscale particles. There are several potential technical and industrial uses for nanomaterials. From the perspective of these many application aspects, this paper examines the Al2O3-H2O nanofluid flow caused by a permeable stretching surface with the influence of an inclined Lorentz force and viscous dissipation. Entropy generation on nanofluid stagnation point flow with the influences of heat generation/absorption, nanoparticles aggregation with suction are also discussed in the current context. With and without nanoparticle aggregation, measurements of velocity, temperature, and entropy production are made. By applying the necessary transformations for heat and motion, ordinary differential equations may be derived from partial differential equations in certain circumstances. For the solution of ordinary differential equations, the Bvp4c technique is used. The effects of several dimensionless limitations on velocity, temperature, and entropy production, skin friction, and Nusselt number profiles are investigated, both when nanoparticle aggregation is present and when it is not. It is concluded that the velocity field is boosted for the velocity ratio and inclined Lorentz force parameters, while the temperature and entropy generation rise for the nanoparticle volume fraction, angle of inclination and Eckert number parameters. The rate of heat transmission improves as a result of the addition of ϕ and ε respectively. When the suction parameter of ε=0.5 is used for the aggregation model, it is claimed that there is an increase of roughly 13.2478% in the heat transfer rate. Temperature and entropy generation profiles for all pertinent parameters is higher for nanoparticles that have aggregated together as opposed to nanoparticles that have not aggregated together. This research was compared with previously published results to validate the findings, and great agreement was found

On green and energy-aware GPU computing for scientific applications

Recently, modern graphics processing unit (GPU) has gained the reputation of computational accelerator that can achieve a significant increase in performance by reducing execution time for the different type of scientific application that demand high performance computing. While modern GPUs reduce the execution time of a parallel application as compared to the CPU implementation, but this performance is sometimes achieved at an expense of considerable power and energy consumption. This paper seeks to characterize and explore the impression of high power consumption in a GPU. We examine this notion by reviewing techniques used by researchers to analyze the performance, power, and energy characteristics of GPUs that are utilized for scientific computing. These studies consider applications that run on a traditional CPU setup, and the transformed parallel applications, running on hybrid CPU+GPU environment. These studies indicated that the heterogeneous CPU+GPU environment delivers an energy-aware and sustainable product that is much better than a traditional CPU application

Mathematical analysis of mixed convective stagnation point flow over extendable porous riga plate with aggregation and joule heating effects

It is still not quite apparent how suspended nanoparticles improve heat transmission. Multiple investigations have demonstrated that the aggregation of nanoparticles is a critical step in improving the thermal conductivity of nanofluids. However, the thermal conductivity of the nanofluid would be greatly affected by the fractal dimension of the nanoparticle aggregation. The purpose of this research is to learn how nanoparticle aggregation, joule heating, and a heat source affect the behavior of an ethylene glycol-based nanofluid as it flows over a permeable, heated, stretched vertical Riga plate and through a porous medium. Numerical solutions to the present mathematical model were obtained using Mathematica's Runge-Kutta (RK-IV) with shooting technique. In the stagnation point flow next to a permeable, heated, extending Riga plate, heat transfer processes and interrupted flow phenomena are defined and illustrated by diagrams in the proposed mixed convection, joule heating, and suction variables along a boundary surface. Data visualizations showed how different variables affected temperature and velocity distributions, skin friction coefficient, and the local Nusselt number. The rates of heat transmission and skin friction increased when the values of the suction parameters were raised. The temperature profile and the Nusselt number both rose because of the heat source setting. The increase in skin friction caused by changing the nanoparticle volume fraction from φ=0.0 to φ=0.01 for the without aggregation model was about 7.2% for the case of opposing flow area (λ=−1.0) and 7.5% for the case of aiding flow region (λ=1.0). With the aggregation model, the heat transfer rate decreases by approximately 3.6% for cases with opposing flow regions (λ=−1.0) and 3.7% for cases with assisting flow regions (λ=1.0), depending on the nanoparticle volume fraction and ranging from φ=0.0 to φ=0.01, respectively. Recent findings were validated by comparing them to previously published findings for the same setting. There was substantial agreement between the two sets finding