This thesis explores the rapidly growing phenomenon of equity crowdfunding from the perspective of professional investors. The aim was to contribute to the relatively thin aca-demic field of equity crowdfunding, shedding light on why it is yet to be recognized as an important instrument for raising capital and provide suggestions for improvement. The data was collected through semi-structured in-depth interviews with Angel Investors that through their experience could identify benefits and constraints with equity crowd-funding not obvious to the crowd. Benefits of using equity crowdfunding platforms were outweighed by the identified constraints such as corporate governance issues, uncertainties concerning laws and regulations, high risk, and lack of intellectual capital. This eventually led to suggestions for improvements that included channelling the crowd investments through a mutual fund, and allowing the crowd to co-invest with Angel Investors to get around the constraints. Conclusively, the Angel Investors were positive towards the underlying ideology of equity crowdfunding of helping more entrepreneurial ventures reaching their full potential by tapping a previously unutilized source of capital, the crowd. However, there is scepticism to how the phenomenon is currently working in practice.

The thesis investigates how Agent-Based Modeling and Simulation (ABMS) and Queueing Theory (QT) techniques help manage mass gathering (MG) crowds. The techniques are applied to Hajj MG, which is one of the most complex annual MG, with a focus on its challenging Tawaf ritual. The objective is to develop a Tawaf Decision Support System (DSS) to better understand Tawaf crowd dynamics and discover decisions that lead to superior performance. TawafSIM is an ABMS model in the DSS, which simulates macro-level Tawaf crowd dynamics through micro-level pilgrim modeling to explore the impact of crowd characteristics, facility layout, and management preferences on emergent crowd behaviours with respect to throughput, satisfaction, health, and safety. Whereas, TawafQT is a QT model in the DSS to explore the impact of pilgrim arrival rate and Tawaf throughput on expected arrival, departure, and waiting times along with average queue length in the Tawaf waiting area. The thesis provides several contributions, including the following. First, it is the only Tawaf research to use a hybrid ABMS and QT approach. Second, TawafSIM is a comprehensive Tawaf simulator. It incorporates features for pilgrim characteristics, facility design, and management preferences. It calculates eight metrics for Tawaf performance, which includes one for throughput, three for satisfaction, one for health, and three for safety. It is the only Tawaf simulator to estimate satisfaction and spread of infectious disease. It conducts 42 simulation experiments in 12 categories. It generates observations for emergent, tipping point, expected, and counter intuitive behaviours. It recommends a default scenario as the best decision along with a small subset of alternative scenarios, which provide above average Tawaf performance. It generates a Tawaf Crowd Management Guide to better understand Tawaf crowd dynamics and how to pursue above average Tawaf performance under different conditions. Third, TawafQT is the only study of the Tawaf waiting area. It uses an accurate queueing model with finite source, single service, and PH type distribution, which is not only applicable to the Tawaf and other Hajj related queueing systems but also to any queueing system, which has finite population and single service characteristics.

SILVA JÚNIOR, Erasmo Artur da. Método dinâmico para troca de representação em sistemas híbridos de renderização de multidões. 2013. 52 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Computação, Fortaleza-CE, 2013. / Submitted by guaracy araujo (guaraa3355@gmail.com) on 2016-06-21T19:52:02Z No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) / Approved for entry into archive by guaracy araujo (guaraa3355@gmail.com) on 2016-06-21T19:53:00Z (GMT) No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) / Made available in DSpace on 2016-06-21T19:53:00Z (GMT). No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) Previous issue date: 2013 / Environments populated with crowds are employed in various applications, such as games, simulators and editors. Many of these environments require not only a realistic and detailed rendering, but it must run smoothly in real-time. This task easily exhausts the system’s resources, even considering the current state-of-the-art hardware. Therefore, crowd rendering in real-time remains a challenge in computer graphics. Approaches exploiting levels of detail, visibility culling and image-based rendering are presented in order to facilitate this task. The first two increase the efficiency of rendering, but sometimes are not enough to keep an interactive frame rate. Some researches on this subject focus on image-based rendering techniques, specifically with the use of impostors. In this work it is proposed a method that balances the computational demand of rendering job by varying the threshold’s distance of the representation switch between full geometry (mesh) and image-based(impostors) models in accordance with the available resources. / Ambientes providos de multidões são empregados em diversas aplicações, como jogos, simuladores e editores. Muitas destas aplicações não requerem somente a renderização de agentes animados de forma realística e detalhada, mas que seja executada suavemente em tempo real, tarefa que facilmente esgota os recursos do sistema (mesmo considerando hardware no estado da arte). Por conta disso,a renderização de multidões em tempo real permanece como um desafio dentro da computação gráfica. Abordagens explorando nível de detalhe, descarte por visibilidade e renderização baseada em imagens foram propostas no intuito de viabilizar esta tarefa. As duas primeiras aumentam a eficiência da renderização, mas as vezes não são suficientes para manter taxas de quadros por segundo interativas. Grande parte dos estudos acerca do tema se concentra em técnicas de renderização baseadas em imagem, especificamente com o emprego de impostores. Neste trabalho é proposto um método que faz o balanço da demanda computacional da renderização através da variação da distância do limiar onde ocorre a troca de representação entre os modelos de geometria completa (malhas) e os baseados em imagem (impostores) de acordo com os recursos disponíveis.

SILVA JÚNIOR, Erasmo Artur da. Método dinâmico para troca de representação em sistemas híbridos de renderização de multidões. 2013. 61 f. Dissertação (Mestrado em ciência da computação)- Universidade Federal do Ceará, Fortaleza-CE, 2013. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-11T13:53:21Z No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2016-07-15T13:37:49Z (GMT) No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) / Made available in DSpace on 2016-07-15T13:37:49Z (GMT). No. of bitstreams: 1 2013_dis_easilvajunior.pdf: 12555422 bytes, checksum: fafd7f37a684a97a47f66846c82081ed (MD5) Previous issue date: 2013 / Environments populated with crowds are employed in various applications, such as games, simulators and editors. Many of these environments require not only a realistic and detailed rendering, but it must run smoothly in real-time. This task easily exhausts the system’s resources, even considering the current state-of-the-art hardware. Therefore, crowd rendering in real-time remains a challenge in computer graphics. Approaches exploiting levels of detail, visibility culling and image-based rendering are presented in order to facilitate this task. The first two increase the efficiency of rendering, but sometimes are not enough to keep an interactive frame rate. Some researches on this subject focus on image-based rendering techniques, specifically with the use of impostors. In this work it is proposed a method that balances the computational demand of rendering job by varying the threshold’s distance of the representation switch between full geometry (mesh) and image-based(impostors) models in accordance with the available resources. / Ambientes providos de multidões são empregados em diversas aplicações, como jogos, simuladores e editores. Muitas destas aplicações não requerem somente a renderização de agentes animados de forma realística e detalhada, mas que seja executada suavemente em tempo real, tarefa que facilmente esgota os recursos do sistema (mesmo considerando hardware no estado da arte). Por conta disso,a renderização de multidões em tempo real permanece como um desafio dentro da computação gráfica. Abordagens explorando nível de detalhe, descarte por visibilidade e renderização baseada em imagens foram propostas no intuito de viabilizar esta tarefa. As duas primeiras aumentam a eficiência da renderização, mas as vezes não são suficientes para manter taxas de quadros por segundo interativas. Grande parte dos estudos acerca do tema se concentra em técnicas de renderização baseadas em imagem, especificamente com o emprego de impostores. Neste trabalho é proposto um método que faz o balanço da demanda computacional da renderização através da variação da distância do limiar onde ocorre a troca de representação entre os modelos de geometria completa (malhas) e os baseados em imagem (impostores) de acordo com os recursos disponíveis.

Ao observar a situação atual, na qual atos de vandalismo e terrorismo tornaram-se frequentes e cada vez mais presentes ao redor do mundo, principalmente em grandes cidades, torna-se clara a necessidade de equipar as forças policiais com tecnologias de observação e monitoramento inteligentes, capazes de identificar e monitorar indivíduos potencialmente perigosos que possam estar infiltrados nas multidões. Ao mesmo tempo, com sua recente popularização, veículos aéreos não tripulados, também chamados VANTs e conhecidos popularmente como "drones", acabaram por tornar-se ferramentas baratas e eficientes para diversas aplicações, incluindo observação, fornecendo a seus utilizadores a capacidade de monitorar alvos, áreas, ou prédios de forma segura e quase imperceptível. Unindo estas duas tendências, este trabalho apresenta o desenvolvimento de um sistema multi-VANT para observção de alvos móveis em multidões, demonstrando a possibilidade de utilização de pequenos VANTs comerciais comuns para o monitoramento de grupos de pedestres. O principal objetivo de tal sistema é monitorar continuamente indivíduos de interesse em um grupo de pessoas, visitando cada um destes indivíduos alternadamente, de forma a manter um registro geral do estado de cada um deles Um sistema deste tipo poderia, por exemplo, ser utilizado por autoridades no controle de manifestações e outras atividades em que grandes grupos de pessoas estejam envolvidos, ajudando a polícia e outros órgãos a identificar indivíduos com comportamento suspeito ou agressivo mais rapidamente, evitando ou minimizando os efeitos de atitudes de vandalismo e de ataques terroristas. Com o intuíto de abordar tal problema da forma mais completa e adequada possível, esta tese apresenta a concepção e o desenvolvimento de um sistema híbrido composto de três diferentes algoritmos: um algoritmo de distribuição de alvos; um de roteamento; e um de repasse de alvos. Primeiramente, neste sistema, um algoritmo de distribuição de alvos baseado em um paradigma de mercado que simula um leilão distribui os alvos entre os VANTs da melhor forma possível. Os VANTs, por sua vez, utilizam um algoritmo genético de roteamento para resolver uma instância do Problema do Caixeiro Viajante e decidir a melhor rota para visitar cada alvo sob sua responsabilidade. Ao mesmo tempo, o sistema analisa a necessidade de redistribuição dos alvos, ativando um algoritmo capaz de realizar esta ação ao perceber sua necessidade quando na iminência de perder algum alvo de vista. Ao fim de seu desenvolvimento, o sistema proposto foi testado em uma série de experimentos especialmente desenvolvidos para avaliar seu desempenho em situações controladas e comprovar sua eficiência para realizar a missão pretendida. / Observing the current scenario, where terrorism and vandalism acts have become commonplace, particularly in big cities, it becomes clear the need to equip law enforcement forces with an efficient observation method, capable of identifying and observing potentially threatening individuals on crowds, to avoid or minimize damage in case of attacks. Moreover, with the popularization of small lightweight Unmanned Aerial Vehicles (UAVs), these have become an affordable and efficient tool, which can be used to track and follow targets or survey areas or buildings quietly, safely and almost undetectably. This work presents the development of a multi-UAV based crowd monitoring system, demonstrating a system that uses small Commercial Of The Shelf (COTS) UAVs to periodically monitor a group of moving walking individuals. The goal of this work is to develop a coordination system for a swarm of UAVS capable of continuously monitoring a large group of individuals (targets) in a crowd, alternately observing each of them at a time while trying to not lose sight of any of these targets. A system equipped with a group of UAVs running this proposal can be used for law-enforcement applications, assisting authorities to monitor crowds in order to identify and to follow suspicious individuals that can have attitudes that could be classified as vandalism or linked to terrorist attack attempts To address this problem a system composed of three parts is proposed and was developed in this thesis. First, an auction algorithm was put in place to distribute interest targets among the multiple UAVs. The UAVs, in turn, make use of a genetic algorithm to calculate the order in which they would visit each of the targets on their observation queue. Moreover, a target handover algorithm was also implemented to redistribute targets among the UAVs in case the system judged that a target was about to be lost by its current observer UAV. The proposed system was evaluated through a set of experiments set-up to verify and to demonstrate the system capabilities to perform such monitoring task, proving its efficiency. During these experiments, it is made clear that the system as a whole has a great potential to solve this kind of moving target monitoring problem that can be mapped to a Time Dependent Travel Salesman Problem (TDTSP), observing targets, and redistributing them among UAVs as necessary during the mission.

Ao observar a situação atual, na qual atos de vandalismo e terrorismo tornaram-se frequentes e cada vez mais presentes ao redor do mundo, principalmente em grandes cidades, torna-se clara a necessidade de equipar as forças policiais com tecnologias de observação e monitoramento inteligentes, capazes de identificar e monitorar indivíduos potencialmente perigosos que possam estar infiltrados nas multidões. Ao mesmo tempo, com sua recente popularização, veículos aéreos não tripulados, também chamados VANTs e conhecidos popularmente como "drones", acabaram por tornar-se ferramentas baratas e eficientes para diversas aplicações, incluindo observação, fornecendo a seus utilizadores a capacidade de monitorar alvos, áreas, ou prédios de forma segura e quase imperceptível. Unindo estas duas tendências, este trabalho apresenta o desenvolvimento de um sistema multi-VANT para observção de alvos móveis em multidões, demonstrando a possibilidade de utilização de pequenos VANTs comerciais comuns para o monitoramento de grupos de pedestres. O principal objetivo de tal sistema é monitorar continuamente indivíduos de interesse em um grupo de pessoas, visitando cada um destes indivíduos alternadamente, de forma a manter um registro geral do estado de cada um deles Um sistema deste tipo poderia, por exemplo, ser utilizado por autoridades no controle de manifestações e outras atividades em que grandes grupos de pessoas estejam envolvidos, ajudando a polícia e outros órgãos a identificar indivíduos com comportamento suspeito ou agressivo mais rapidamente, evitando ou minimizando os efeitos de atitudes de vandalismo e de ataques terroristas. Com o intuíto de abordar tal problema da forma mais completa e adequada possível, esta tese apresenta a concepção e o desenvolvimento de um sistema híbrido composto de três diferentes algoritmos: um algoritmo de distribuição de alvos; um de roteamento; e um de repasse de alvos. Primeiramente, neste sistema, um algoritmo de distribuição de alvos baseado em um paradigma de mercado que simula um leilão distribui os alvos entre os VANTs da melhor forma possível. Os VANTs, por sua vez, utilizam um algoritmo genético de roteamento para resolver uma instância do Problema do Caixeiro Viajante e decidir a melhor rota para visitar cada alvo sob sua responsabilidade. Ao mesmo tempo, o sistema analisa a necessidade de redistribuição dos alvos, ativando um algoritmo capaz de realizar esta ação ao perceber sua necessidade quando na iminência de perder algum alvo de vista. Ao fim de seu desenvolvimento, o sistema proposto foi testado em uma série de experimentos especialmente desenvolvidos para avaliar seu desempenho em situações controladas e comprovar sua eficiência para realizar a missão pretendida. / Observing the current scenario, where terrorism and vandalism acts have become commonplace, particularly in big cities, it becomes clear the need to equip law enforcement forces with an efficient observation method, capable of identifying and observing potentially threatening individuals on crowds, to avoid or minimize damage in case of attacks. Moreover, with the popularization of small lightweight Unmanned Aerial Vehicles (UAVs), these have become an affordable and efficient tool, which can be used to track and follow targets or survey areas or buildings quietly, safely and almost undetectably. This work presents the development of a multi-UAV based crowd monitoring system, demonstrating a system that uses small Commercial Of The Shelf (COTS) UAVs to periodically monitor a group of moving walking individuals. The goal of this work is to develop a coordination system for a swarm of UAVS capable of continuously monitoring a large group of individuals (targets) in a crowd, alternately observing each of them at a time while trying to not lose sight of any of these targets. A system equipped with a group of UAVs running this proposal can be used for law-enforcement applications, assisting authorities to monitor crowds in order to identify and to follow suspicious individuals that can have attitudes that could be classified as vandalism or linked to terrorist attack attempts To address this problem a system composed of three parts is proposed and was developed in this thesis. First, an auction algorithm was put in place to distribute interest targets among the multiple UAVs. The UAVs, in turn, make use of a genetic algorithm to calculate the order in which they would visit each of the targets on their observation queue. Moreover, a target handover algorithm was also implemented to redistribute targets among the UAVs in case the system judged that a target was about to be lost by its current observer UAV. The proposed system was evaluated through a set of experiments set-up to verify and to demonstrate the system capabilities to perform such monitoring task, proving its efficiency. During these experiments, it is made clear that the system as a whole has a great potential to solve this kind of moving target monitoring problem that can be mapped to a Time Dependent Travel Salesman Problem (TDTSP), observing targets, and redistributing them among UAVs as necessary during the mission.

The aim of this thesis is to study some of the challenges that the Kurdish language and its standardization face, and offer a bottom-up solution through the “collective intelligence” and “good faith collaboration” of Wikipedia. Therefore, the fragmentation in the Kurdish language—caused by both external factors and those that are inherent to the language itself— is discussed and analyzed. Furthermore, this thesis describes some of the efforts that have been made to unify the Kurdish language, its dialects and its different writing systems. Even though these issues exist both in the physical world as well as online, they are rendered more conspicuous on the Internet. As a result, the problems in Kurdish cross-dialect communication are more pronounced. In spite of that, web 2.0 and its favored platforms for online collaboration provide ample opportunity for the general user of the language to participate in solving such linguistic problems. An overview of Wikipedia, as the world’s most successful platform for online collaboration, is presented along with some of its rules and policies. Additionally, an account of the current Kurdish Wikipedia in three dialects of Kurdish: Kurmanji, Sorani and Zazaki is provided. The situation and shortcomings of Kurdish versions of Wikipedia are examined through two case studies based on two Wikipedia articles in Kurdish and their English and Persian counterparts. Moreover, I argue that a robust Kurdish Wikipedia can be a viable solution for standardizing the language, encouraging orthographic consistency, and unifying Kurdish writing systems and knowledge/information dissemination in Kurdish. / +46762801113

Co-creation is a new approach to the development of videogames, films, television, music and other creative services. It is a manifestation of open innovation paradigm where the firm collaborates with customers in new service development (NSD) activities. Firm can either co-create with individual customers, or with customer communities. Customers may substantially contribute to ideation, design, production, testing, marketing or distribution of a new or existing service. Customer networks, because of their intrinsic and extrinsic motivations, contribute to the development of services. They have a potential to innovate, as their ideas come from the outside of the organization and reflect their need-related knowledge. Via co-creation a firm can also learn about unarticulated or future customer needs, and what kind of service features they would pay the most for. Co-creation has also benefits for marketing. By inviting customers to participate in their activities, firms can capitalize on positive word of mouth and increased value ascribed to their services. They can also engage in new models of raising finance, i.e. crowdfunding. We studied thirteen videogames firms in North America and in Western Europe. Our goal was to gain insight into their NSD activities when customers were also involved. We observed those studios’ co-creation practices, tracked their communications with customers, and spoke to employees in all levels and functions of those firms. We also participated in various related events. We identified three ideal types of co-creation practice: structured, semi-structured, and loose, and ordered the firms into three cases according to these types. We investigate the main factors that determine co-creation’s practice in firms, as well as firms’ ability co-create. This includes a firm’s propensity for and style of co-creation. We identify four relevant co-creation competences which, together with funding arrangements and organizational culture, influence co-creation. We find that co-creation can occur via formal, as well as informal channels. Informal co-creation takes place on the level of individual interactions between employees and customers (and is linked to hidden innovation), while formal relies on the strategic use of contests, volunteer programs, as well as other legally-regulated exchanges. Firms can use co-creation in NSD to source ideas from the customers, as well as to enhance their marketing by redefining customer relationship. Still, co-creation also has a profound transformative effect on the organization itself. We identify the sites within a firm that are affected by co-creation. Those sites go beyond just the content of the service, and include functions of the firm that normally are hidden from customers (back-end and service design functions). The new service development is also affected. Similarly, the way that firm interacts with its customers is transformed, too.

Les chercheurs au travers de plusieurs domaines essaient de fournir des solutions pour intégrer les objets et les systèmes dans l’internet des objets (IdO ou IoT pour Internet of Things en anglais). Il y a deux domaines parmi les domaines les plus importants d’IdO. Le premier est de tester et évaluer l’IdO. Plusieurs milliards d’objets sont déjà connectés à l’internet. Ces objets peuvent communiquer entre eux directement sans intervention humaine. Les entreprises et les développeurs doivent être capable de tester et d’évaluer des scénarios différents dans plusieurs environnements. Ces environnements doivent être capable d’échanger des services entre eux. Nous présentons notre architecture IoTaaS (Internet of Things Testing As A Service). IoTaaS est un environnement distribué pour tester et évaluer l’IdO. Nous présentons aussi la première mise en oeuvre expérimentale qui est appelée CEMAT (Cloud Environment for Mobile Application Testing) qui permet de tester les applications mobiles et les objets connectés. Le deuxième domaine correspond aux méthodes de communication. Nous présentons notre conception de communications COLDE (Connectionless Data Exchange) pour échanger une petite quantité de données publiques entre les clients Wi-Fi et les points d’accès sans qu’ils aient besoin d’être associés. Alors que COLDE présente la méthode nécessaire pour échanger ces données, le concept de services Lightweight décrit les données échangées en utilisant le protocole COLDE. / Researchers across many domains are working to provide solutions that enable integration of objectsand systems into the Internet of Things (IoT). There are two domains which are among the mostimportant ones in IoT. First domain is IoT testing and evaluation. The billions of objects whichare connected to IoT would intercommunicate without any human intervention. Enterprises anddevelopers should be able to test and evaluate different operational scenarios of their systems indifferent environments. Testing environments should be able to exchange services. We present ourarchitecture IoTaaS (Internet of Things Testing As A Service). IoTaaS is a hierarchy of a distributedcloud for testing and evaluating IoT. We also present the pilot implementation of IoTaaS under thecode name CEMAT (Cloud Environment for Mobile Application Testing) which focuses on mobiledevices and their connected objects. The second domain is about communication methods andtechniques. Several IoT applications depend on public data exchange. We present our design toexchange small amount of public data on wireless network without establishing a connection. COLDE(Connectionless Data Exchange) is our extension to protocol the IEEE 802.11. COLDE utilizesthe management frames to allow Wi-Fi devices and access points to exchange small amounts ofdata without having any association. COLDE describes how we can exchange data without beingconnected. Lightweight services concept explains which data could be transferred using COLDE.Simulation experiments and real world implementation are presented along with their results.

Que ce soit dans une rue commerçante, un supermarché ou un aéroport, les phénomènes de foule sont incontournables et nous affecte au quotidien. Elle constitue un système complexe dont la dynamique collective, résultant des interactions individuelles, est difficile à appréhender et a toujours intrigué les scientifiques de différents domaines. Grâce au progrès technologique, il est aujourd'hui possible de modéliser les mouvements de foule et de les reproduire en simulation. Les simulations de mouvement de foule permettent aux chercheurs de plusieurs disciplines, comme les sciences sociales ou la biomécanique, de mieux étudier et comprendre les mouvements des piétons et leurs interactions. Quant aux sciences de la sécurité et du transport, ils y voient des applications concrètes comme le développement de modèles de foule capables de simuler l'évacuation d'un lieu public de moyenne ou de forte affluence, afin que les futures constructions ou aménagements publics puissent offrir une qualité de sécurité et de service optimale pour les usagers. Dans le cadre de cette thèse, nous avons travaillé sur le perfectionnement du modèle discret proposé et développé par l'équipe dynamique du laboratoire Navier. Dans ce modèle, les actions et les décisions de chaque piéton sont traitées individuellement. Trois aspects du modèle ont été traités dans cette thèse. Le premier concerne la navigation des piétons vers leurs destinations. Dans notre modèle, un piéton est représenté par une particule ayant une direction et une allure souhaitées. Cette direction est obtenue par la résolution d'une équation eikonale. La solution de cette équation permet d'obtenir un champ de vitesses qui attribue à chaque piéton, en fonction de sa position, une direction vers sa destination. La résolution de l'équation une fois ou à une période quelconque donne la stratégie du chemin le plus court ou le plus rapide respectivement. Les effets des deux stratégies sur la dynamique collective de la foule sont comparés. Le deuxième consiste à gérer le comportement des piétons. Après avoir choisi son chemin, un piéton doit interagir avec l'environnement (obstacles, topologie, ...) et les autres piétons. Nous avons réussi à intégrer trois types de comportement dans notre modèle: (i) la poussée en utilisant une approche originale, basée sur la théorie des collisions des corps rigides dans un cadre thermodynamique rigoureux, (ii) le passage agressif (forcer son chemin) modélisé par une force sociale répulsive et (iii) l'évitement ``normal'' en adoptant une approche cognitive basée sur deux heuristiques. Les performances des trois méthodes ont été comparées pour plusieurs critères. Le dernier aspect concerne la validation et la vérification du modèle. Nous avons réalisé une étude de sensibilité et validé le modèle qualitativement et quantitativement. À l'aide d'un plan d'expérience numérique nous avons réussi à identifier les paramètres d'entrée ayant les effets principaux sur les résultats du modèle. De plus, nous avons trouvé les différentes interactions entre ces paramètres. En ce qui concerne la validation qualitative, nous avons réussi à reproduire plusieurs phénomènes d'auto-organisation. Enfin, nous avons testé la capacité de notre modèle à reproduire des résultats expérimentaux issus de la littérature. Nous avons choisi le cas du goulot d'étranglement. Les résultats du modèle et ceux de l'expérience ont été comparés. Ce modèle de foule a également été appliqué à l'acheminement des piétons dans la gare de Noisy-Champs. L'objectif de cette application est d'estimer le temps de stationnement des trains dans la gare / Crowds are present almost everywhere and affect several aspects of our lives. They are considered to be on of the most complex systems whose dynamics, resulting from individual interactions and giving rise to fascinating phenomena, is very difficult to understand and have always intrigued experts from various domains. The technological advancement, especially in computer performance, has allowed to model and simulate pedestrian movement. Research from different disciplines, such as social sciences and bio-mechanics, who are interested in studying crowd movement and pedestrian interactions were able to better examine and understand the dynamics of the crowd. Professionals from architects and transport planners to fire engineers and security advisors are also interested in crowd models that would help them to optimize the design and operation of a facility. In this thesis, we have worked on the imporvement of a discrete crowd model developed by the researchers from the dynamics group in Navier laboratory. In this model, the actions and decisions taken by each individual are treated. In its previous version, the model was used to simulate urgent evacuations. Three main aspects of the model were addressed in this thesis. The first one concerns pedestrian navigation towards a final destination. In our model, a pedestrian is represented by a disk having a willingness to head to a certain destination with a desired direction and a desired speed. A desired direction is attributed to each pedestrian, depending on his position from the exit, from a floor field that is obtained by solving the eikonal equation. Solving this equation a single time at the beginning of the simulation or several times at during the simulation allows us to obtain the shortest path or the fastest path strategy respectively. The influence of the two strategies on the collective dynamics of the crowds is compared. The second one consists of managing pedestrian-pedestrian interactions. After having chosen his/her direction according to one of the available strategies, a pedestrian is bound to interact with other pedestrians present on the chosen path. We have integrated three pedestrian behaviors in our model: (i) pushing by using an original approach based on the theory of rigid body collisions in a rigorous thermodynamics context, (ii) forcing one's way by introducing a social repulsive force and (iii) "normal" avoidance by using a cognitive approach based on two heuristics. The three methods are compared for different criteria. The last aspect is the validation and verification of the model. We have performed a sensibility study and validated the model qualitatively and quantitatively. Using a numerical experimental plan, we identified the input parameters that are the most statistically significant and estimated the effects of their interactions. Concerning qualitative validation, we showed that our model is able to reproduce several self-organization phenomena such as lane formation. Finally, our model was validated quantitatively for the case of a bottleneck. The experimental results are very close to the ones obtained from simulations. The model was also applied to pedestrian movement in the Noisy-Champs train station. The objective of the study was to estimate the train dwell time. The simulation results were similar to the observations