Predicting encounter and colocation events

Although an extensive literature has been devoted to mine and model mobility features, forecasting where, when and whom people will encounter/colocate still deserve further research effort s. Forecasting people\u2019s encounter and colocation features is the key point for the success of many applications rang- ing from epidemiology to the design of new networking paradigms and services such as delay tolerant and opportunistic networks. While many algorithms which rely on both mobility and social informa- tion have been proposed, we propose a novel encounter and colocation predictive model which predicts user\u2019s encounter and colocation events and their features by exploiting the spatio-temporal regularity in the history of these events. We adopt a weighted features Bayesian predictor and evaluate its accuracy on two large scales WiFi and cellular datasets. Results show that our approach could improve prediction accuracy with respect to standard na\uefve Bayesian and some of the state of the art predictors

HUMAN MOBILITY IN URBAN SPACE

Nowadays we witness a rapid increase of people mobility as the world population has become more interconnected and is relying on faster transportation methods, simplified connections and shorter commuting times. Unveiling and understanding human mobility patterns have become a crucial issue to support decisions and prediction activities when managing the complexity of the today's social organization. The strict connections between human mobility patterns, the planning, deployment and management of a variety of public and commercial services have fueled the rise of a vast research activity. Throughout this work, we are more interested and mainly focusing on urban mobility because here most of the human interactions take place and mobility has the greatest impact on management and optimization of public and commercial services. In this thesis, we provided a general framework for dealing with the modeling importance of locations from a per-user perspective and identified a few novel properties of human mobility. Also through characterizing the transition patterns driving user movement among visited places, we pave the way to propose a new mobility model in urban spaces. Meanwhile relying on the relevance of visited places, we propose a new algorithm for detecting and distinguishing Home and Workplaces. And finally, we suggest a framework for predicting the different aspects of Encounter/Colocation events. By exploiting the weighted Bayesian predictor we could enhance the accuracy of prediction w.r.t. the standard naive Bayesian and also to some other state-of-the-art predictors

Impact of overlapping in the radio coverage areas of multiple Wi-Fi access points on detecting encounters

Understanding the potential role of Smartphones and other portable wireless devices as relay nodes in message dissemination and content delivery in Delay Tolerant and Opportunistic networks depend on the knowledge about patterns and the number of encounter events among mobile nodes. One of the main challenges for extracting encounters is overlapping in the radio coverage areas of nearby access points (APs). Data about the usage of Wi-Fi networks can be used to perform an analysis of encounters among mobile devices. A realistic estimation of the number of encounters among mobile nodes is now a big challenge. In this paper, the effects of overlapping of radio coverage area among multiple APs for extracting realistic encounters among mobile devices has been discussed, and also an analytical approach has been proposed for extracting realistic encounters from overlapping in the coverage areas of multiple nearby APs. A significant difference was observed between the number of encounters by considering and ignoring overlapping. Our study finds that Wi-Fi datasets are not reliable source to estimate the number of encounters when there are overlapping in radio coverage areas of multiple APs

Characterizing Communicability of Networks formed on Mobile Node

Smartphones have become extremely popular by launching wide ubiquitous networks. Nowadays studying of DTN Delay Tolerant Networks (DTN) and Opportunistic Networks where formed over these mobile nodes, is one of the interesting topics in the research community. In this paper, we measure communicability capacity of DTN Network formed over the mobile nodes at a university campus and also an area in Montreal city through exploiting static and temporal graphs. We observed a significant difference between communicability measures in static and temporal cases, especially for short snapshot windows. It implies that analyzing dynamic networks by considering a static model for them may lead to an unrealistic and even mislead results

LIPIcs, Volume 277, GIScience 2023, Complete Volume

LIPIcs, Volume 277, GIScience 2023, Complete Volum

The potential influence of cognitive linguistics in second language teaching

Treballs Finals del Grau d'Estudis Anglesos, Facultat de Filologia, Universitat de Barcelona, Curs: 2016-2017, Tutora: Rosanna Rión Tetas[eng] Any development in the field of linguistics has the potential to influence second language teaching. However, the applications of cognitive linguistics to second language teaching have not received much attention from scholars. This essay builds upon theories from cognitive linguistics, selecting the ideas that have the most potential to benefit second language teaching and suggesting some ways in which cognitive linguistics could be applied to second language teaching. Then this project analyzes some of the challenges that have to be overcome in order to apply cognitive linguistics to second language teaching in a more efficient way. Finally, this essay proposes task-based language teaching as the most suitable teaching approach to benefit from cognitive linguistics.[cas] Cualquier desarrollo en el campo de la lingüística puede, potencialmente, tener un efecto en la docencia de lenguas extranjeras. Sin embargo, las aplicaciones de la lingüística cognitiva en el campo de la docencia de lenguas extranjeras no han recibido demasiada atención por parte de los expertos en la materia. Este trabajo se basa en las teorías del campo de la lingüística cognitiva y selecciona las ideas que tienen más potencial para beneficiar a la docencia de lenguas extranjeras y propone cómo estas ideas se podrían aplicar. A continuación, este trabajo analiza algunos de los problemas que se han de tratar para poder aplicar la lingüística cognitiva de una manera más eficiente. Finalmente, este trabajo propone que el método de enseñanza basado en tareas es el método que encaja mejor con este movimiento lingüístico

Content Sharing in Mobile Networks with Infrastructure: Planning and Management

This thesis focuses on mobile ad-hoc networks (with pedestrian or vehicular mobility) having infrastructure support. We deal with the problems of design, deployment and management of such networks. A first issue to address concerns infrastructure itself: how pervasive should it be in order for the network to operate at the same time efficiently and in a cost-effective manner? How should the units composing it (e.g., access points) be placed? There are several approaches to such questions in literature, and this thesis studies and compares them. Furthermore, in order to effectively design the infrastructure, we need to understand how and how much it will be used. As an example, what is the relationship between infrastructure-to-node and node-to-node communication? How far away, in time and space, do data travel before its destination is reached? A common assumption made when dealing with such problems is that perfect knowledge about the current and future node mobility is available. In this thesis, we also deal with the problem of assessing the impact that an imperfect, limited knowledge has on network performance. As far as the management of the network is concerned, this thesis presents a variant of the paradigm known as publish-and-subscribe. With respect to the original paradigm, our goal was to ensure a high probability of finding the requested content, even in presence of selfish, uncooperative nodes, or even nodes whose precise goal is harming the system. Each node is allowed to get from the network an amount of content which corresponds to the amount of content provided to other nodes. Nodes with caching capabilities are assisted in using their cache in order to improve the amount of offered conten

Colocation aware content sharing in urban transport

People living in urban areas spend a considerable amount of time on public transport. During these periods, opportunities for inter-personal networking present themselves, as many of us now carry electronic devices equipped with Bluetooth or other wireless capabilities. Using these devices, individuals can share content (e.g., music, news or video clips) with fellow travellers that happen to be on the same train or bus. Transferring media takes time; in order to maximise the chances of successfully completing interesting downloads, users should identify neighbours that possess desirable content and who will travel with them for long-enough periods. In this thesis, a peer-to-peer content distribution system for wireless devices is proposed, grounded on three main contributions: (1) a technique to predict colocation durations (2) a mechanism to exclude poorly performing peers and (3) a library advertisement protocol. The prediction scheme works on the observation that people have a high degree of regularity in their movements. Ensuring that content is accurately described and delivered is a challenge in open networks, requiring the use of a trust framework, to avoid devices that do not behave appropriately. Content advertising methodologies are investigated, showing their effect on whether popular material or niche tastes are disseminated. We first validate our assumptions on synthetic and real datasets, particularly movement traces that are comparable to urban environments. We then illustrate real world operation using measurements from mobile devices running our system in the proposed environment. Finally, we demonstrate experimentally on these traces that our content sharing system significantly improves data communication efficiency, and file availability compared to naive approaches

Effect of co-location in the Johannesburg Securities Exchange (JSE)

Thesis (M.M.(Finance & Investment)--University of the Witwatersrand, Faculty of Commerce, Law and Management, Wits Business School, 2016Co-location on the JSE took place on the 14th of May 2014. This dissertation looks at the impact this event has had on the market. In order to measure the effects of colocation, market quality factors are examined before and after the event to see whether there were any significant changes. A regression is then undertaken to see the correlation between co-location, liquidity and volatility. Our results suggest that colocation benefits market liquidity but we are unable to assess the relationship with volatility. This means that the growing liquidity in the market can be used to attract more institutions and firms wishing to run trading algorithms and strategies. Trades originally meant for dark pools can be now traded on the JSE co-location servers. By moving trades from dark pools to co-location servers at the JSE and encouraging institutions to use these facilities, transparency can be increased. Exchanges should implement kill switches if it is apparent that they are being impaired or flooded with erroneous orders. The deployment of kill switches, circuit breakers and other system compliance will improve investor confidence and market stability. Subsequent research can lead to better understanding by investigating the correlation between colocation and volatility.MT 201

Anticipatory Mobile Computing: A Survey of the State of the Art and Research Challenges

Today's mobile phones are far from mere communication devices they were ten years ago. Equipped with sophisticated sensors and advanced computing hardware, phones can be used to infer users' location, activity, social setting and more. As devices become increasingly intelligent, their capabilities evolve beyond inferring context to predicting it, and then reasoning and acting upon the predicted context. This article provides an overview of the current state of the art in mobile sensing and context prediction paving the way for full-fledged anticipatory mobile computing. We present a survey of phenomena that mobile phones can infer and predict, and offer a description of machine learning techniques used for such predictions. We then discuss proactive decision making and decision delivery via the user-device feedback loop. Finally, we discuss the challenges and opportunities of anticipatory mobile computing.Comment: 29 pages, 5 figure