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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Tracking Pedestrians with Known/Unknown Interactions and Influences

Krishnan, Krishanth 11 1900 (has links)
This thesis addresses the problem of tracking multiple ground targets whose motion is dependent on one another. Multiple approaches which integrate the social force based motion model into different filtering algorithms are proposed. The social force concept has previously been used to model pedestrian motion where the interactions among pedestrians are described using social forces. First, the social force based motion model integrated into the Probability Hypothesis Density (PHD) framework is proposed. Two different implementations, namely, the Sequential Monte Carlo (SMC) technique and the Gaussian Mixture (GM) technique, are derived to implement the proposed Social Force PHD (SF-PHD) filter in ground target tracking scenarios. Next, a social-force-based motion model integrated into the stacked Kalman filter (stacked SF-KF) is developed and its multiple model (stacked IMM-SF-KF) variant is derived. Then, the assumption used in the proposed algorithms, that the actual values of the social force parameters are known, is not valid at all times and the assumption is relaxed. Hence, simultaneous parameter estimation techniques for the social force parameters during the tracking are proposed. Three approaches based on the state augmentation method, the Expectation Maximization (EM) method and the maximum likelihood method are derived. The maximum likelihood method can be implemented offline or online, depending on the requirement. The traditional Posterior Cramer Rao Lower Bound (PCRLB), which is the inverse of the Fisher information matrix, gives a bound on the optimal achievable accuracy of the estimated state of a target with independent motion. Subsequently, a modified performance measure based on the PCRLB for targets whose motion is dependent on each other is derived to validate the performance of the proposed algorithms. Finally, the PCRLB that accounts for unknown interactions is derived to validate the proposed simultaneous parameter estimation techniques. Simulated and real data are used to show the performance of the proposed algorithms and simultaneous parameter estimation techniques compared to the algorithms in the literature. / Thesis / Doctor of Philosophy (PhD) / This thesis addresses the problem of tracking multiple ground targets whose motion is dependent on one another. In target tracking literature, it is commonly assumed that a target’s motion follows a nearly constant velocity, constant turn or a constant acceleration model independent of the motion of other targets. But the actual behavior of a ground target may be more intricate than that and it is often affected by the motion of other targets, obstacles in the surrounding and its intended destination. Hence, a more sophisticated motion modeling technique, which integrates the various factors that affect the motion of ground targets, is needed. In this thesis, multiple approaches which integrate the social force based motion model into different filtering algorithms are proposed. The social force concept has previously been used to model pedestrian motion where the interactions among pedestrians are described using social forces. First, the social force based motion model integrated into the Probability Hypothesis Density (PHD) framework is proposed. Two different implementations, namely, the Sequential Monte Carlo (SMC) technique and the Gaussian Mixture (GM) technique, are derived to implement the proposed Social Force PHD (SF-PHD) filter in ground target tracking scenarios. Next, a social-force-based motion model integrated into the stacked Kalman filter (stacked SF-KF) is developed and its multiple model (stacked IMM-SF-KF) variant is derived. Then, the assumption used in the proposed algorithms, that the actual values of the social force parameters are known, is not valid at all times and the assumption is relaxed. Hence, simultaneous parameter estimation techniques for the social force parameters during the tracking are proposed. Three approaches based on the state augmentation method, the Expectation Maximization (EM) method and the maximum likelihood method are derived. The maximum likelihood method can be implemented offline or online, depending on the requirement. The traditional Posterior Cramer Rao Lower Bound (PCRLB), which is the inverse of the Fisher information matrix, gives a bound on the optimal achievable accuracy of the estimated state of a target with independent motion. Subsequently, a modified performance measure based on the PCRLB for targets whose motion is dependent on each other is derived to validate the performance of the proposed algorithms. Finally, the PCRLB that accounts for unknown interactions is derived to validate the proposed simultaneous parameter estimation techniques. Simulated and real data are used to show the performance of the proposed algorithms and simultaneous parameter estimation techniques compared to the algorithms in the literature.
2

Analysis of the influence of the characteristics of the environment on the time of pedestrian transhipment in a multimodal transport using the social force model

Asenjo, Christian, Tocas, Frank, Silvera, Manuel, Campos, Fernando 30 September 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The Highway Capacity Manual (HCM-2010) indicates in Volume III (Chapter 17) how the characteristics of the environment can represent obstacles that influence the determination of the average pedestrian space. However, the HCM does not specifically analyse in detail how these obstacles affect specifically the path, speed and average walking time of pedestrian. This article performs a comparative analysis between two microsimulations models where it is evidence how by not considering the characteristics of the fixed and mobile environment, the transhipment time and the speed of people are modified. As a case study, the obstacles present in the environment during the transhipment carried out by users in an integrated multimodal transport system in the city of Lima are identified. The comparative analysis between both cases shows the influence of the characteristics of the environment of the transhipment and variation in the average speed of the pedestrians. The proposed study methodology is calibrated and validated by microsimulations in Vissim Software. The comparative analysis reflects an increase in the transhipment time of 19.4% and a decrease in the average speed of the pedestrians by 14.8 %, reflecting in the microsimulation model values near to the real behaviour of pedestrians.
3

Microscopic Modeling of Crowds Involving Individuals with Physical Disability: Exploring Social Force Interaction

Stuart, Daniel S. 01 May 2015 (has links)
It has been shown that nearly one quarter of a population is affected by a disability which influences their interaction with the built environments, other individuals, and evacuation policies inhibiting their exit ability during an emergency evacuation. It is predicted that the number of individuals with a disability is on the rise. In the 21st century alone, there have been hundreds of events attributed to stampede or crowd crush, natural disaster, political revolt, terrorism, and other related emergencies. With an increase in the world's population, understanding emergency evacuations and how to best apply them is of growing importance. While research has investigated how crowds interact and evacuate, very little has been investigated in the impacts of how the disabled change an evacuation. While there are some beginnings to affect modeling with heterogeneous behaviors of disabled, little has been known in the analysis of crowds involving individuals with disabilities. There is a need to understand and model such interaction and how it impacts crowd movement. This dissertation implements and develops a novel video tracking system to study heterogeneous crowds with individuals with disabilities towards conducting a large-scale crowd experiment. A large-scale crowd experiment is conducted and the results are analyzed through a developed analysis graphical user interface for use with crowd dynamics experts. Preliminary results of the large-scale crowd experiment demonstrate differences in the velocities and overtaking perception of various groups with disabilities composed of the visually impaired, individuals with motorized and non-motorized wheelchairs, individuals with roller walkers, and individuals with canes or other stamina impairments. This dissertation uses these results to present a hybrid Social Force model that can capture the overall overtake behavior of the empirical data from our crowd experiments. Finally, future research goals are discussed in the eventual development of a Mass Pedestrian Evacuation system for crowds with individuals with disabilities. Lessons from this dissertation are discussed towards goals of crowd control.
4

Collective Pedestrian Motion Under Vehicle Influence: Social Force Based Modeling and Application in Intelligent Transportation

Yang, Dongfang January 2020 (has links)
No description available.
5

K diskurzivní tvorbě normových autorit na německých školách a její vliv na formování spisovné němčiny / On the Discursive Constitution of Language Norm Authorithies in German Schools and Their Influence on the Creation of the Standard Variety

Horbank, Olivia Josephine January 2014 (has links)
This master thesis analyzes the question, how norm authority constitutes itself in the context of school education. It is based on firsthand data from several adio- and audiovisual recordings of classes in two German schools (trade school and high school). The project provides a description of the mechanism by which the teacher establishes himself as the norm-authority and how he is able to assert this authority towards the student, the norm subject. At the same time, the reaction of the norm subjects towards the intervention of the norm authority into their language production is analyzed. Theoretically, the essay is embedded in the social force field of a standard-variety ("soziales Kräftefeld einer Standardvarietät") by Ulrich Ammon and the language management theory. By following the steps of the language management process, the handling of the language norm is described and an analysis is made of how language norms are actively adopted into the learning process. The analysis and evaluation of the class recordings underline the dynamic character of language norms and show the procedural nature of norm formation and their adoption. Key Words: norm, variety, social force field, language management, macro and micro level, norm authority, norm subject
6

DECISION-MAKING FOR AUTONOMOUS CONSTRUCTION VEHICLES

Marielle, Gallardo, Sweta, Chakraborty January 2019 (has links)
Autonomous driving requires tactical decision-making while navigating in a dynamic shared space environment. The complexity and uncertainty in this process arise due to unknown and tightly-coupled interaction among traffic users. This thesis work formulates an unknown navigation problem as a Markov decision process (MDP), supported by models of traffic participants and userspace. Instead of modeling a traditional MDP, this work formulates a Multi-policy decision making (MPDM) in a shared space scenario with pedestrians and vehicles. The employed model enables a unified and robust self-driving of the ego vehicle by selecting a desired policy along the pre-planned path. Obstacle avoidance is coupled within the navigation module performing a detour off the planned path and obtaining a reward on task completion and penalizing for collision with others. In addition to this, the thesis work is further extended by analyzing the real-time constraints of the proposed model. The performance of the implemented framework is evaluated in a simulation environment on a typical construction (quarry) scenario. The effectiveness and efficiency of the elected policy verify the desired behavior of the autonomous vehicle.
7

Another world is possible: Tourism, globalisation and the responsible alternative

Higgins-Desbiolles, B. Freya, Freya.HigginsDesbiolles@unisa.edu.au January 2006 (has links)
Utilising a critical theoretical perspective, this work examines contemporary corporatised tourism and capitalist globalisation. This analysis suggests that marketisation limits the understanding of the purposes of tourism to its commercial and “industrial” features, thereby marginalising wider understandings of the social importance of tourism. Sklair’s conceptualisation of capitalist globalisation and its dynamics, as expressed in his “sociology of the global system” (2002), is employed to understand the corporatised tourism phenomenon. This thesis explains how a corporatised tourism sector has been created by transnational tourism and travel corporations, professionals in the travel and tourism sector, transnational practices such as the liberalisation being imposed through the General Agreement on Trade in Services negotiations and the culture-ideology of consumerism that tourists have adopted. This thesis argues that this reaps profits for industry and exclusive holidays for privileged tourists, but generates social and ecological costs which inspire vigorous challenge and resistance. This challenge is most clearly evident in the alternative tourism movement which seeks to provide the equity and environmental sustainability undermined by the dynamics of corporatised tourism. Alternative tourism niches with a capacity to foster an “eco-humanism” are examined by focusing on ecotourism, sustainable tourism, pro-poor tourism, fair trade in tourism, community-based tourism, peace through tourism, volunteer tourism and justice tourism. While each of these demonstrates certain transformative capacities, some prove to be mild reformist efforts and others promise more significant transformative capacity. In particular, the niches of volunteer tourism and justice tourism demonstrate capacities to mount a vigorous challenge to both corporatised tourism and capitalist globalisation. Since the formation of the Global Tourism Interventions Forum (GTIF) at the World Social Forum gathering in Mumbai in 2004, justice tourism has an agenda focused on overturning corporatised tourism and capitalist globalisation, and inaugurating a new alternative globalisation which is both “pro-people” and sustainable. Following the development of these original, macro-level conceptualisations of tourism and globalisation, this thesis presents a micro-level case study of an Indigenous Australian tourism enterprise which illustrates some of these dynamics in a local context. Camp Coorong Race Relations and Cultural Education Centre established and run by the Ngarrindjeri Aboriginal community of South Australia has utilised tourism to foster greater equity and sustainability by working towards reconciliation through tourism. The Ngarrindjeri have also experienced conflicts generated from the pressures of inappropriate tourism development which has necessitated an additional strategy of asserting their Indigenous rights in order to secure Ngarrindjeri lifeways. The case study analysis suggests that for alternative tourism to create the transformations that contemporary circumstances require, significant political change may be necessary. This includes fulfilment of economic, social and cultural rights to which a majority of nations have committed but have to date failed to implement. While this is a challenge for nation-states and is beyond the capacities of tourism alone, tourism nonetheless can be geared toward greater equity and sustainability if the perspective that corporatised tourism is the only option is resisted. This thesis demonstrates that another tourism is possible; one that is geared to public welfare, human fulfilment, solidarity and ecological living.
8

Contextual information aided target tracking and path planning for autonomous ground vehicles

Ding, Runxiao January 2016 (has links)
Recently, autonomous vehicles have received worldwide attentions from academic research, automotive industry and the general public. In order to achieve a higher level of automation, one of the most fundamental requirements of autonomous vehicles is the capability to respond to internal and external changes in a safe, timely and appropriate manner. Situational awareness and decision making are two crucial enabling technologies for safe operation of autonomous vehicles. This thesis presents a solution for improving the automation level of autonomous vehicles in both situational awareness and decision making aspects by utilising additional domain knowledge such as constraints and influence on a moving object caused by environment and interaction between different moving objects. This includes two specific sub-systems, model based target tracking in environmental perception module and motion planning in path planning module. In the first part, a rigorous Bayesian framework is developed for pooling road constraint information and sensor measurement data of a ground vehicle to provide better situational awareness. Consequently, a new multiple targets tracking (MTT) strategy is proposed for solving target tracking problems with nonlinear dynamic systems and additional state constraints. Besides road constraint information, a vehicle movement is generally affected by its surrounding environment known as interaction information. A novel dynamic modelling approach is then proposed by considering the interaction information as virtual force which is constructed by involving the target state, desired dynamics and interaction information. The proposed modelling approach is then accommodated in the proposed MTT strategy for incorporating different types of domain knowledge in a comprehensive manner. In the second part, a new path planning strategy for autonomous vehicles operating in partially known dynamic environment is suggested. The proposed MTT technique is utilized to provide accurate on-board tracking information with associated level of uncertainty. Based on the tracking information, a path planning strategy is developed to generate collision free paths by not only predicting the future states of the moving objects but also taking into account the propagation of the associated estimation uncertainty within a given horizon. To cope with a dynamic and uncertain road environment, the strategy is implemented in a receding horizon fashion.
9

Simulação de multidões com agentes brownianos e modelo de forças sociais modificado / Crowd simulation with brownian agents and modified model of social forces

Saboia, Priscila Corrêa 16 August 2018 (has links)
Orientador: Siome Klein Goldenstein / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-16T21:25:11Z (GMT). No. of bitstreams: 1 Saboia_PriscilaCorrea_M.pdf: 2582894 bytes, checksum: 1645aa6b8b779ee7180adbbb04d23981 (MD5) Previous issue date: 2010 / Resumo: Atualmente, estima-se que a população mundial seja de cerca de seis bilhões e oitocentos milhões de habitantes (6.800.000.000), dos quais metade mora em aglomerados urbanos. Nestes centros, é corriqueiro o fen¿omeno da movimentação de multidões. Tecnicamente, entende-se multidão como um grande grupo de indivíduos em um mesmo ambiente físico, compartilhando um objetivo comum e podendo agir diferentemente do que quando estão sozinhos. Compreender a movimentação destas multidões é de vital import¿ancia para o planejamento e a melhoria dos locais públicos, não só no sentido de facilitar e agilizar o deslocamento dos cidadãos, mas também garantir-lhes segurança, especialmente em condições de perigo iminente, onde pode haver a necessidade de evacuação de tais locais. Além disso, existem várias áreas do conhecimento que têm potencial para se beneficiar do estudo do comportamento de multidões. Na indústria de entretenimento, por exemplo, simulações de multidões podem ser utilizadas na produção de animações e jogos de computador. No treinamento policial e militar, simulações podem ser usadas para demonstração e controle de rebeliões. Na área de engenharia de segurança, simulações podem ser utilizadas para estudo de desocupação emergencial de construções, navios e aviões. Em todas as áreas citadas, observa-se que a necessidade por simulações de multidões advém de duas situações que podem ocorrer no mundo real. Primeiramente, pode ser perigoso para os indivíduos realizar as ações objetivadas (como cair de um prédio em um filme, ou evacuar uma sala de cinema em chamas, por exemplo), bem como é antiético submetê-los a tais condições. Segundo, é muito complexo e oneroso lidar com um grande número de indivíduos no mundo real. Ambas as situações podem ser evitadas pela simulação computacional da situação real. Nestes termos, o objetivo desta dissertação é modelar a movimentação de multidões, tendo em vista a simulação em computador. Para tanto, sistemas multiagentes brownianos são introduzidos como uma alternativa tecnológica 'a implementação dos modelos encontrados na literatura, bem como 'a implementação de um novo modelo de movimentação de multidões, híbrido por reunir conceitos de modelos que lançam mão das chamadas forças sociais, com conceitos de modelos baseados na estratégia Lattice-Gas. Como resultado prático, um novo simulador de sistemas multiagentes construído para a tarefa de simulação de movimentação de multidões é apresentado / Abstract: Currently, it is estimated that world population is about six billion and eight hundred million inhabitants (6.8 billion), of whom half live in urban areas. In these centers, it is common the phenomenon of moving crowds. Technically, a crowd can be seen as a large group of individuals put in the same physical environment, sharing a common goal and acting differently than when they are alone. Understanding the movement of these crowds is very important for planning and improving public places, not only in order to facilitate and expedite the movement of citizens, but also in order to guarantee their safety, especially in conditions of imminent danger, where it can be necessary the evacuation of such sites. Furthermore, there are several areas of knowledge that can gain benefits from the study of crowd behavior. In the entertainment industry, for example, crowd simulations can be used to produce animations and computer games. In Police and military training, simulations can be used for demonstration and control of riots. In the area of safety engineering, simulations can be used to study the urgent evacuation of buildings, ships and aircrafts. In all mentioned areas, it is observed that the need for crowd simulations comes from two situations, taking into consideration the real world. First, it can be dangerous for individuals to perform the desired actions (like falling from a building in a movie, or evacuating the room on fire of a failing movie session). It is also unethical to expose them to such conditions. Second, it is very complex and expensive to handle a large number of individuals in the real world. Both situations can be dealt by simulating the real world into a computer. Thus, this dissertation aims to model the movement of crowds, always having in mind the computer simulation. For this, Brownian multi-agent systems are introduced as a technological alternative to implement the models found in literature, as well as to implement a new hybrid movement model, that gathers together concepts from solutions based on social forces, and solutions based on Lattice- Gas. As a practical result, a new simulator for multi-agent systems is presented, built for the task of simulating moving crowds / Mestrado / Sistemas de Informação / Mestre em Ciência da Computação
10

Microsimulation of Public Transport Stops for the Optimization of Waiting Times for Users Using the Social Force Model

Mendoza, Francis, Tong, Mayling, Silvera, Manuel, Campos, Fernando 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Cities in the world aim to ensure the mobility of people, through the implementation of efficient Integrated Transportation Systems (ITS). This aims to improve the transport of people, which guarantees that they can be mobilized safely and without delays in the terminals and bus stops of the public transport system. The present article proposes a design of public transport stops aimed at optimizing the waiting time of users when transferring from one bus to another. For the validity of the proposal, the social force model of the Vissim program was used, where the behavior of the users within the bus stops was reflected. The results showed that the waiting times in the calibrated and validated microsimulation model were optimized by approximately 20%, which generates an improvement in the efficiency of the public transport system. / Revisión por pares

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