Each year people are injured and even die in crowd related accidents, often during planned events. Recent studies have emphasized the need for using a systems approach to study these events. In this study the systems approach of resilience theory is combined with the crowd psychology-models Extended Social Identity Model and the Aggravation and Mitigation Model to examine event safety at a music festival, a domain previously largely unexplored by these perspectives. By using an ethnographic approach as well as interviewing visitors the study set out to answer questions about when and how the safety organization adjusted itself under conditions relating to crowds. Another goal was to study the social identity of the visitors as well as the interaction between the safety organization and the visitors at the festival to explain the presence or absence of crowd conflict. Using thematic analysis several situations were identified where the safety organization adjusted itself, as well as the strategies that the organization used in these different circumstances. It was also concluded that the absence of crowd conflict could best be explained by three factors. First of all, no history of crowd conflict existed between the safety organization and the visitors, secondly, there were no groups present with the goal of creating conflict, and thirdly, the social processes taking place between the safety organization and the visitors were all mitigating in nature. The mitigating nature of the social processes was partly attributable to the strategies identified for adjusting to crowd conditions.

Motion is an important cue in videos that captures the dynamics of moving objects. It helps in effective analysis of various event related tasks such as human action recognition, anomaly detection, tracking, crowd behavior analysis, traffic monitoring, etc. Generally, accurate motion information is computed using various optical flow estimation techniques. On the other hand, coarse motion information is readily available in the form of motion vectors in compressed videos. Utilizing these encoded motion vectors reduces the computational burden involved in flow estimation and enables rapid analysis of video streams. In this work, the focus is on analyzing motion patterns, retrieved from either motion vectors or optical flow, in order to do various event analysis tasks such as video classification, anomaly detection and crowd flow segmentation. In the first section, we utilize the motion vectors from H.264 compressed videos, a compression standard widely used due to its high compression ratio, to address the following problems. i) Video classification: This work proposes an approach to classify videos based on human action by capturing spatio-temporal motion pattern of the actions using Histogram of Oriented Motion Vector (HOMV) ii) Crowd flow segmentation: In this work, we have addressed the problem of flow segmentation of the dominant motion patterns of the crowds. The proposed approach combines multi-scale super-pixel segmentation of the motion vectors to obtain the final flow segmentation. iii) Anomaly detection: This problem is addressed by local modeling of usual behavior by capturing features such as magnitude and orientation of each moving object. In all the above approaches, the focus was to reduce computations while retaining comparable accuracy to pixel domain processing. In second section, we propose two approaches for anomaly detection using optical flow. The first approach uses spatio-temporal low level motion features and detects anomalies based on the reconstruction error of the sparse representation of the candidate feature over a dictionary of usual behavior features. The main contribution is in enhancing each local dictionary by applying an appropriate transformation on dictionaries of the neighboring regions. The other algorithm aims to improve the accuracy of anomaly localization through short local trajectories of super pixels belonging to moving objects. These trajectories capture both spatial as well as temporal information effectively. In contrast to compressed domain analysis, these pixel level approaches focus on improving the accuracy of detection with reasonable detection speed.

Aujourd’hui, les appareils mobiles sont présents dans le monde entier. Ces appareils permettent aux utilisateurs d'accéder à l’Internet notamment par l'intermédiaire des réseaux WiFi. La diversité et le nombre de déploiements sans coordination centrale (y compris les utilisateurs à leur domicile) conduit à des déploiements qu’on peut qualifier de chaotiques. En conséquence, les réseaux WiFi sont largement déployés avec une forte densité dans les zones urbaines. Dans ce contexte, les utilisateurs et les opérateurs tentent d’exploiter ces déploiements pour obtenir une connectivité omniprésente, et éventuellement d'autres services. Cependant, pour tirer parti de ces déploiements, il faut des stratégies pour identifier les réseaux utilisables et choisir les plus adaptés aux besoins. Pour cela, nous étudions le processus de découverte des réseaux dans le contexte de ces déploiements. Ensuite, nous présentons une plateforme de partage de mesures sans fil, un système d'information collaboratif où les stations mobiles recueillent des mesures du réseau et les envoient à un système central. En rassemblant mesures provenant de différents utilisateurs, la plateforme donne accès à des caractéristiques du déploiement précieuses. Nous évaluons l'utilité de cette plateforme collaborative grâce à deux applications : (1) l’ensemble minimal de points d'accès, afin de réduire l'énergie nécessaire pour offrir une couverture WiFi dans une zone donnée. (2) l'optimisation des paramètres de recherche de réseau, afin de réduire le temps nécessaire pour découvrir les réseaux existants. Ensuite, nous étudions une méthode passive pour déterminer si un réseau fonctionne dans un canal saturé. / Nowadays, mobile devices are present worldwide, with over 4.40 Billion devices globally. These devices enable users to access the Internet via wireless networks. Different actors (e.g., home users, enterprises) are installing WiFi networks everywhere, without central coordination, creating chaotic deployments. As a result, WiFi networks are widely deployed all over the world, with high accesspoint (AP) density in urban areas. In this context, end-users and operators are trying to exploit these dense network deployments to obtain ubiquitous Internet connectivity, and possibly other services. However, taking advantage of these deployments requires strategies to gather and provide information about the available networks. In this dissertation, we first study the network discovery process within the context of these deployments. Then, we present the Wireless Measurements Sharing Platform, a collaborative information system, to which mobile stations send simple network measurements that they collected. By gathering and processing several network measurements from different users, the platform provides access to valuable characteristics of the deployment. We evaluate the usefulness of this collaborative platform thanks to two applications: (1) the minimal access point set, to reduce the energy needed to offer WiFi coverage in a given area.(2) The optimization of the scanning parameters,to reduce the time a mobile station needs for the network discovery. Finally, we describe a method to identify whether an AP operates ina saturated channel, by passively monitoring beacon arrival distribution.

Submitted by PPG Ci?ncia da Computa??o (ppgcc@pucrs.br) on 2018-10-04T19:48:28Z No. of bitstreams: 1 Paulo_Ricardo_Knob_dis.pdf: 15412485 bytes, checksum: d5fc868fa02ec06b2e29e6848c4b37ae (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-10-08T14:18:54Z (GMT) No. of bitstreams: 1 Paulo_Ricardo_Knob_dis.pdf: 15412485 bytes, checksum: d5fc868fa02ec06b2e29e6848c4b37ae (MD5) / Made available in DSpace on 2018-10-08T14:37:58Z (GMT). No. of bitstreams: 1 Paulo_Ricardo_Knob_dis.pdf: 15412485 bytes, checksum: d5fc868fa02ec06b2e29e6848c4b37ae (MD5) Previous issue date: 2018-08-22 / A maioria das t?cnicas dispon?veis hoje em dia para simula??o de multid?es est? focada em uma situa??o espec?fica, por exemplo, evacua??o em eventos perigosos. Poucas t?cnicas consideram os aspectos culturais e de personalidade presentes em uma sociedade para determinar o comportamento dos agentes. Portanto, este trabalho tem como objetivo construir um framework capaz de lidar com diferentes teorias culturais e de personalidade como input, traduzindo-as em uma parametriza??o de grupo, que vai determinar o comportamento de grupos e multid?es em ambientes virtuais. Al?m disso, inclu?mos no BioCrowds uma resposta de conforto para os agentes, em termos de densidade e caracter?sticas t?rmicas do ambiente. Os resultados indicam que os mapeamentos culturais / psicol?gicos parecem promissores, uma vez que os agentes foram capazes de se comportar conforme o esperado. Al?m disso, os agentes foram capazes de reagir devido ao conforto t?rmico e de densidade, melhorando sua capacidade de reagir ?s mudan?as do ambiente. / Most of the techniques available nowadays for crowd simulation are focused on a specific situation, e.g. evacuation in hazardous events. Very few of them consider the cultural and personality aspects present in a society to determine the behavior of agents. Therefore, this work aims to build a framework able to deal with different cultural and personality theories as input, and translate them into a group parametrization, which is going to determine the behavior of groups and crowds in virtual environments. Also, we include in BioCrowds a comfort response for agents, in terms of density and thermal characteristics of the environment. Results indicate that the cultural/psychological mappings seem promising, since agents were able to perform as intended. Additionally, agents were able to react due to thermal and density comfort, improving their ability to react to environmental changes.

This thesis looks into the economics of crowdsourcing using game theoretic modeling. The art of aggregating information and expertise from a diverse population has been in practice since a long time. The Internet and the revolution in communication and computational technologies have made this task easier and given birth to a new era of online resource aggregation, which is now popularly referred to as crowdsourcing. Two important features of this aggregation technique are: (a) crowdsourcing is always human driven, hence the participants are rational and intelligent, and they have a payoff function that they aim to maximize, and (b) the participants are connected over a social network which helps to reach out to a large set of individuals. To understand the behavior and the outcome of such a strategic crowd, we need to understand the economics of a crowdsourcing network. In this thesis, we have considered the following three major facets of the strategic crowdsourcing problem. (i) Elicitation of the true qualities of the crowd workers: As the crowd is often unstructured and unknown to the designer, it is important to ensure if the crowdsourced job is indeed performed at the highest quality, and this requires elicitation of the true qualities which are typically the participants' private information. (ii) Resource critical task execution ensuring the authenticity of both the information and the identity of the participants: Due to the diverse geographical, cultural, socio-economic reasons, crowdsourcing entails certain manipulations that are unusual in the classical theory. The design has to be robust enough to handle fake identities or incorrect information provided by the crowd while performing crowdsourcing contests. (iii) Improving the productive output of the crowdsourcing network: As the designer's goal is to maximize a certain measurable output of the crowdsourcing system, an interesting question is how one can design the incentive scheme and/or the network so that the system performs at an optimal level taking into account the strategic nature of the individuals. In the thesis, we design novel mechanisms to solve the problems above using game theoretic modeling. Our investigation helps in understanding certain limits of achievability, and provides design protocols in order to make crowdsourcing more reliable, effective, and productive.

The global increase in the number of mass gatherings and crowded events has brought with it new emergencies and unintended consequences for public administrators and first responders. Crowd managers attempt to overcome these challenges by enhancing operations, alleviating financial losses, keeping event organizers safe from liability and, most importantly, keeping the attendees safe. Effective communication among and between officials and guests has been identified as a key element in this process. However, there is a lack of risk communication studies, especially about heterogeneous crowds that congregate at religious events. With this gap in mind, this research aims to investigate the use of major communication channels available and/or preferred by Muslim pilgrims in Makkah, Saudi Arabia during Hajj to gauge their effectiveness in communicating risk information. This annual religious pilgrimage was chosen because it attracts over 2 million pilgrims from more than 140 countries, most of whom speak different languages and belong to different cultures but perform the same rituals at the same time. This dissertation seeks to answer three broad research questions: “what are the most popular communication channels used by pilgrims,” “what are the weaknesses of the current communication strategies,” and “what can be done to improve risk communication among pilgrims, and between pilgrims and authorities to enhance crowd control and crowd management strategies.” The protective action decision model (PADM) is used as the theoretical framework to understand the influence of six factors (environmental cues, social cues, information sources, channel access and preferences, warning messages, and receiver characteristics) on risk communication. In collaboration with the Transportation and Crowd Management Center of Research Excellence (TCMCORE) of Saudi Arabia, a convenience sampling strategy was employed to interview 348 pilgrims in the Prophet’s Mosque area, during the Hajj of 2013. The surveys were conducted in Arabic and English and included pilgrims from different backgrounds and countries. Data analysis included an evaluation of the correlation between the use of risk communication channels and receiver characteristics, message content, and information sources. Findings highlight low percentages in the overall use of communication channels. It also demonstrated an over-dependence on channels that foster the passive top-down communication strategy (such as TV stations, messages at mosques, billboard, text messages, and pamphlets), while marginalizing channels that foster the horizontal and bottom-up strategies (such as bilingual staff outreach and social media). The findings also show the differences in risk communication channels used by pilgrims from different socio-demographic groups. The study concludes that adopting bottom-up and horizontal strategies is key to effective risk communication. Additionally, crowd managers must recognize the importance of social media and use this medium more proactively. They can also work towards increasing the overall effectiveness of risk communication channels by addressing the impact of information sources, channel access, and receiver characteristics to better suit the needs of pilgrims. Finally, the study states the limitations and future research directions.

The aim of this thesis is to inspect and identify available technologies and services in order to develop a prototype web application, based on acrowd funding idea, for a startup company. The prototype is going to be used for attracting investments, for further development, and it implements essential functionality such as social login, and a user interface focused on statistics and a payment service.The project was conducted in three main areas, a research phase, a development phase and a documentation phase. All the choices that have been made during the project have been considered with other possible solutions at the research phase by investigating the advantages and disadvantages of the solutions. In conclusion, the thesis examines the web application prototype as a final result, evaluates design decisions and solution choices made in there search phase and recommends possible extension routes of the system for further application development. The thesis hopes to offer useful information and a good starting point for students that are considering developing an application based on a crowd funding model or an Enterprise application using similar technologies. / Syftet med denna studien är att undersöka och identifiera tillgängligateknologiska lösningar och tjänster för utveckling av en webbapplikation prototyp, baserad på en crowdfunding idé, för ett nystartat företag. Prototypen kommer att användas för att locka inverterare som är villiga att vidareutveckla prototypen. De grundläggande funktionaliteten såsom social inloggning, och et tanvändargränssnitt med fokus på statistik och en betaltjänst är implementerat i prototypen. Projektet utfördes i tre huvudsakliga delar, en undersöknings fas, en utvecklins fas och dokumentations fas. Alla valen som har gjorts under projektets gång har övervägts med andra möjliga val under undersökningsfasen genom att ta fram för och nackdelar. Avslutningsvis undersöker studien den slutliga prototypen som ett slutresultat, utvärderar designbeslut och lösnings val som har gjorts under forskningsfasen och rekommenderar eventuella tilläggsmöjligheter för vidareutveckling. Studien förväntas kunna ge användbar information och en bra utgångspunkt för projekt som överväger att utveckla ett program som bygger på en crowdfunding modell eller ett Enterprise program med liknande teknologi.

Mobile Crowd Sensing (MCS) or Participatory Sensing (PS) are two emerging systems as smart mobile devices become ubiquitous. One of the advantages of such a sensing system is that almost anyone with a mobile device can become a moving "sensor". However, despite the convenience, the openness of such systems is a double-edged sword: participants can misbehave and pose a threat. Usually, current MCS or PS systems are relatively weak and lack effective data sources selection mechanisms. As a result, fake or forged data can be collected, representing wrongly the sensed conditions on the surroundings, i.e. noise, moisture, etc. Therefore, a Hardened Registration Process (HRP) is proposed to provide a pre-examination on participants that are chosen to collect sensing data. There is one previous work on such a topic. It targets device examination (root, emulator, bot-net detection, etc.) for Android devices, preventing attackers from managing to register not actual but emulated devices and thus manage to effectively manipulate the collected data. The focus of this project is on enhancing the previous work and extending it with complementary mechanisms. We proposed a two-step HRP process, comprising a client detection for identifying malicious devices and server-side detection for revealing Sybil devices. We improve the previous HRP by implementing detection mechanisms in C (native) code and such an enhanced device examination process is the first step: client detection. In addition, to detect adversaries that can bypass the client detection method, we proposed an additional server-side detection to eliminate emulators and Sybil devices, adopting peer-to-peer interaction with Bluetooth Low Energy to corroborate the physical presence of the registered devices. With this enhancement, we achieve higher detection performance. Adversaries cannot easily bypass the client-side detection with rooted or emulated devices. Moreover, even if some adversaries can bypass the client-side detection, the server-side detection can prevent adversaries from registering Sybil devices more than the number of devices they own. / Mobile Crowd Sensing (MCS) eller Participatory Sensing (PS) är två framväxande system när smarta mobila enheter blir allestädes närvarande. En av fördelarna med ett sådant avkänningssystem är att nästan alla med en mobil enhet kan bli en rörlig sensor". Men trots bekvämligheten är öppenheten i sådana system ett tveeggat svärd: deltagare kan missköta sig och utgöra ett hot. Vanligtvis är nuvarande MCS- eller PS-system relativt svaga och saknar effektiva valmekanismer för datakällor. Som ett resultat kan falska eller förfalskade data samlas in, som felaktigt representerar de avkända förhållandena i omgivningen, d.v.s. buller, fukt, etc. Därför föreslås en förstärkt registreringsprocess för att ge en förundersökning av deltagare som väljs för att samla in avkänningsdata. Det finns ett tidigare arbete om ett sådant ämne. Det är inriktat på enhetsundersökning (root, emulator, bot-net-detektion, etc.) för Android-enheter, vilket förhindrar angripare från att lyckas registrera inte faktiska utan emulerade enheter och på så sätt lyckas effektivt manipulera den insamlade informationen. Fokus för detta projekt ligger på att förbättra det tidigare arbetet och utöka det med kompletterande mekanismer. Vi föreslog en tvåstegs HRP-process, som omfattar en klientdetektering för att identifiera skadliga enheter och detektering på serversidan för att avslöja Sybil-enheter. Vi förbättrar den tidigare HRP genom att implementera detekteringsmekanismer i C (native) kod och en sådan förbättrad enhetsundersökningsprocess är det första steget: klientdetektering. Dessutom, för att upptäcka motståndare som kan kringgå klientdetekteringsmetoden, föreslog vi en extra detektering på serversidan för att eliminera emulatorer och Sybil-enheter, genom att använda peer-to-peer-interaktion med Bluetooth Low Energy för att bekräfta den fysiska närvaron av de registrerade enheterna. Med denna förbättring uppnår vi högre detektionsprestanda. Motståndare kan inte lätt kringgå upptäckten på klientsidan med rotade eller emulerade enheter. Dessutom, även om vissa motståndare kan kringgå upptäckten på klientsidan, kan detekteringen på serversidan förhindra att motståndarna registrerar Sybil-enheter mer än antalet enheter de äger.

The concert industry has been expanded enormously the last couple of years. At the same time as the increasing engagement for concerts, the digital market is growing rapidly. Today during concerts, people use their smartphones to send text messages, connect on social media, take photos, record film clips, and use the flashlight function in a replacement of a lighter. This behaviour may be perceived as a distracting moment and instead moves the person’s focus from the live performance to the phone. The distracting moment can be solved by making an application that makes the interaction more enjoyable through the study of user experience. This can lead to more focus on the music and therefore, enhance the concert experience. In this project, the work behind the development of designing prototypes is described. The method used in the thesis is the process of Design Thinking. The process is divided into a five-step model: empathize, define, ideate, prototype and test. The result presents three prototypes that are based on digital competitions that interact the audience during a concert experience. At the end of the thesis, a discussion about how to secure a positive outcome of interacting the audience and the artist is presented. The conclusion was that the interactions have good potential to work in a concert environment, but the interactions need to be additionally tested to secure a positive outcome. Another conclusion was that the time before a concert has more scope to make interactions work well and to not distract the users from the live performance. / Konsertindustrin har expanderat enormt de senaste åren. Samtidigt som det ökande engagemanget för konserter, växer den digitala marknaden snabbt. Idag använder publiken sina mobiltelefoner under en konsert för att skicka textmeddelanden, ansluta på sociala medier, ta foton, spela in filmklipp och använda ficklampans funktion som en tändare. Det här beteendet kan uppfattas som ett distraherande ögonblick och i stället flytta personens fokus från konserten till telefonen. Det distraherande ögonblicket kan undvikas genom en studie av användarupplevelse som gör att en mobilapplikation gör samspelet smidigare. Det kan leda till mer fokus på musiken och genom det förbättra konsertupplevelsen. I det här projektet beskrivs arbetet bakom utvecklingen av prototyper. Metoden som används i rapporten är processen Design Thinking. Processen är uppdelad i en femstegsmodell: sympatisera, definiera, föreställa, prototyp och testa. Resultatet presenterar tre prototyper som bygger på digitala tävlingar som interagerar publiken under en konsertupplevelse. I slutet av rapporten presenteras en diskussion om hur man kan få ett positivt resultat av att interagera publiken och artisten med varandra. Slutsatsen var att interaktionerna har god potential att fungera i en konsertmiljö, men interaktionerna måste testas ytterligare för att säkerställa ett positivt resultat. En annan slutsats var att tiden före en konsert har mer spelrum för interaktionerna att fungera bra och att inte distrahera användarna från konsertupplevelsen.

A large proportion of the farming in Kenya and Eastern Africa is performed by smallholding farmers. At the same time, consumers are expecting to find foodstuff more close by and in a more convenient way than most smallholding farmers can provide. Crowdsourcing can efficiently be applied to many problems where many small producers need to collaborate to create the complete product, without exposing much of the complex process to the end consumers. Using semi structured interviews, systematic literature review and prototyping, the application of crowdsourcing to reach and empower smallholding farmers was explored. The findings were used to create recommendations in the form of guidelines that are expected to serve as ground work and background to future studies within the area. In general, a mobile based platform for crowdsourcing was found to be viable while still having some problems with the intended target market. Three primary factors which affects the potential success were identified; The generally low availability of internet to smallholding farmers (limited by high prices), lacking education which can limit comprehension of more complicated processes, and smartphones with limited capacity for advanced applications. / En stor del av jordbruket i Kenya och östra Afrika utförs av småbönder. Samtidigt förväntar sig konsumenter att kunna hitta matprodukter närmare och på ett mer bekvämt sätt än de flesta småbönder kan erbjuda. Crowdsourcing kan effektivt tillämpas på många problem där flera små producenter behöver samarbeta för att skapa den kompletta produkten utan att utsätta slutkonsumenten för den komplexa processen. Med hjälp av semi-trukturerade intervjuer, systematisk litteratur studie och prototyping, undersöktes tillämpningen av crowdsourcing för att nå och förstärka småbönder. Resultaten användes för att skapa rekommendationer i form av riktlinjer som förväntas fungera som grundarbete och bakgrund till framtida studier inom området. I allmänhet visade sig en mobilbaserad plattform för crowdsourcing vara realistisk, samtidigt som den fortfarande hade några problem med den avsedda målmarknaden. Tre primära faktorer som påverkar den potentiella framgången identifierades. Dessa var den generellt låga tillgängligheten av internet till småbönder (begränsad av höga priser), avsaknad av utbildning som kan begränsa förståelsen av mer komplicerade processer, och smartphones med begränsad kapacitet för avancerade applikationer.