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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

A secure user authentication scheme for critical mobile applications

Ben Tahayekt Ben Tahaikt, Chaimaa January 2017 (has links)
Smartphones have facilitated tasks in private and work life for its users. In business, employees often should manage sensitive data that unauthorised people cannot access, so some user authentication is needed to perform. Besides the normal user authentication, some employers give the right to access to the sensitive data only if the employees stay in specific locations. That makes sense for those businesses that have various construction sites and offices that are not necessarily located in the same geographical region. In those companies, the employees must be able to perform their tasks from different locations regardless of the available network infrastructure. To protect the data from intruders, this research presents a secure location-based user authentication scheme for mobile application that works offline. This research considers to enable access to the sensitive data using off-the-shelf mobile devices without adding any extra hardware and with no additional information from a fixed infrastructure. This Thesis firstly describes the architecture and attributes of the proposed solution. Then, the techniques used for the design and functionality of the solution are presented. The results of this study reveal that the proposed solution is more suitable for the applications that is used in outdoor locations. Finally, to alleviate the shortcoming of the presented technique for indoor locations, a new method has been discussed and tested. This report is a final Thesis in collaboration with SAAB. The purpose of this research is to examine the best way to protect sensitive data managed by the employees using their smartphones in different workplaces.
2

The use of ambient audio to increase safety and immersion in location-based games

KURCZAK, JOHN JASON 01 February 2012 (has links)
The purpose of this thesis is to propose an alternative type of interface for mobile software being used while walking or running. Our work addresses the problem of visual user interfaces for mobile software be- ing potentially unsafe for pedestrians, and not being very immersive when used for location-based games. In addition, location-based games and applications can be dif- ficult to develop when directly interfacing with the sensors used to track the user’s location. These problems need to be addressed because portable computing devices are be- coming a popular tool for navigation, playing games, and accessing the internet while walking. This poses a safety problem for mobile users, who may be paying too much attention to their device to notice and react to hazards in their environment. The difficulty of developing location-based games and other location-aware applications may significantly hinder the prevalence of applications that explore new interaction techniques for ubiquitous computing. We created the TREC toolkit to address the issues with tracking sensors while developing location-based games and applications. We have developed functional location-based applications with TREC to demonstrate the amount of work that can be saved by using this toolkit.In order to have a safer and more immersive alternative to visual interfaces, we have developed ambient audio interfaces for use with mobile applications. Ambient audio uses continuous streams of sound over headphones to present information to mobile users without distracting them from walking safely. In order to test the effectiveness of ambient audio, we ran a study to compare ambient audio with handheld visual interfaces in a location-based game. We compared players’ ability to safely navigate the environment, their sense of immersion in the game, and their performance at the in-game tasks. We found that ambient audio was able to significantly increase players’ safety and sense of immersion compared to a visual interface, while players performed signifi- cantly better at the game tasks when using the visual interface. This makes ambient audio a legitimate alternative to visual interfaces for mobile users when safety and immersion are a priority. / Thesis (Master, Computing) -- Queen's University, 2012-01-31 23:35:28.946
3

Enabling Locative Experiences

Sampat, Miten 19 December 2007 (has links)
The appropriate framework to capture and share location information with mobile applications enable the development of interfaces and interface techniques that empower users to obtain and share information on the go. As such, the work in this thesis makes two major contributions. First is the SeeVT framework, a locative backbone that uses currently-available data and equipment in the Virginia Tech and Blacksburg VA environments (e.g., wireless signal triangulation, GPS signals) to make available to applications the location of the device in use. Applications built on this framework have available knowledge of the region in which the user's device is located. Second is a set of four applications built on the SeeVT framework: SeeVT – Alumni Edition (a guide for alumni returning to campus, often after lengthy absences), the Newman Project (a library information system for finding books and other library resources), VTAssist (a information sharing system for disabled users), and SeeVT-Art (a guide for users in our local inn and conference center to learn about the art on display). Key in this contribution is our identification and discussion of three interface techniques that emerged from our development efforts: an images-first presentation of information, a lightweight mobile augmented reality style of interaction, and locative content affordances that provide ways to quickly input focused types of information in mobile situations. / Master of Science
4

Manikarnika : Proactive Crowd-Sourcing for Location Based Services

Vaidyanathan, NA January 2010 (has links)
This thesis presents the design and evaluation of the location of a cell phone user, to enable more effective performance monitoring. One of the end-uses I propose is in emergency management, by means of a framework that distributes its functionality between establishing data-set characteristics that are relevant to the problem and a visual tool to evaluate resource-scheduling proposals. Manikarnika is a modular framework, which finds translation in a prototype for Reverse 111. The first steps in the process were to establish whether the parameters I hypothesized as useful, indeed were. Using a statistically significant amount of traces, obtained from real calls placed on the network, the utility of the location metric was established. In order to investigate utilizing a second metric of reputation, a benchmark for evaluating ideas from Social Networks research was proposed, in order to move from arbitrary testing to a more systematic environment. This dissertation details the measurement, design and evaluation of an end-to-end and modular framework for Emergency Management, where the functionality is distributed in order to easily incorporate the changing parameters of sources of information, emergency events, resource requirements of these events and identifying callers that might be able to provide better insight into a situation that is essentially very dynamic. The chasm between research proposals for various end-uses and the application of the same to real life is one that I have tried to bridge in my work. By incorporating pieces from core Electrical Engineering measurements and simulation and extending the use of what was originally a tool built for training Emergency Responders to analyze various resource scheduling agents, which take into account a diversity of administrative domains, I lay the ground work for one possible solution, Reverse 111, which proposes the use of proactive crowd-sourcing for emergency response, with easy extensions to commercial location-based applications.
5

Prediction and influence maximization in location-based social networks.

January 2012 (has links)
基于地理位置的社交网络近年得到了非常多的关注。为了提升用戶粘性和吸引用戶,社交問路提供商会提供給用戶基于地理信息的广告和优惠券等服务。方了让广告和优惠券的投递更有效, 预测用戶下个可能访问的地点变得尤为重要。但是,预测地点一个不可避免的挑战就是數一百万计的候选地点构成了庞大的預測空间,使得整个预测过程变成复杂且缓慢。在本论文中,我們利用用戶签到的类別信息对潜在的用戶运动模式進行了建模并提出了一个混合隐马尔可夫模型去预测用戶下个可能访问的地点类别。基于预测出的类别,我們继而对用戶可能访问的地点进行了預測。在类別层次进行建模的好处是能有效地減少候选地点的个數并且能准确地描述用戶行动的实际意义。一般来說,用戶的行为会受到令人偏好的影响,基于这个現象,我們还运用分类的方法对用戶根据其令人愛好的不同進行了划分并对每个组群制定各自的隐马尔可夫模型。实验結果表示如果先预测用可能访问的地点类别,能使得地点预测空间极大地减少预测精度也会变高。 / 在预测用可能访问的地点之后,另外一个很重要的问题是选择将优惠券投递给哪些用从而将产品或地点的影响最大化。在实际运用中,这种将影响最大化的算法会遇到速度上的壁垒。在本论文中,我们研究了在基于地理位置的社交网络中的影响最大化问题,并提出了一个分割方法能有效地提升算法的运行速度。实验结果显示我们的算法在于业界标准方法达到几乎一致的影响力的前提下,能更快地运行。 / Location-based social networks have been gaining increasing popularity in recent years. To increase users’ engagement with location-based services, it is important to provide attractive features, one of which is geo-targeted ads and coupons. To make ads and coupons delivery more effective, it is essential to predict the location that is most likely to be visited by a user at the next step. However, an inherent challenge in location prediction is a huge prediction space, with millions of distinct check-in locations as prediction target. In this thesis we exploit the check-in category information to model the underlying user movement pattern. We propose a framework which uses a mixed hidden Markov model to predict the category of user activity at the next step and then predicts the most likely location given the estimated category distribution. The advantages of modeling on the category level include a significantly reduced prediction space and a precise expression of the semantic meaning of user activities. In addition, as user check-in behaviors are heavily influenced by their preferences, we take a clustering approach to group users with similar preferences, and train a separate hidden Markov model for each group. Extensive experimental results show that, with the predicted category distribution, the number of location candidates for prediction is much smaller, while the location prediction accuracy becomes higher. / Choosing the right users to deliver the coupons and maximizing the influence spread is also an important problem in LBSN, which is called influence maximization problem. In practice speed is an important issue to solve the influence maximization problem. In this thesis, we study the influence maximization problem in location-based social networks and propose a scalable partition approach to solve the influence maximization problem efficiently. Experimental results show that our partition approach achieves quite similar influence spread performance with the original influence maximization approach, while running much faster. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhu, Zhe. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 93-101). / Abstracts also in Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background Study --- p.11 / Chapter 2.1 --- Location prediction --- p.11 / Chapter 2.2 --- Influence maximization --- p.16 / Chapter 3 --- User Activity and Location Prediction in Location-based Social Networks --- p.20 / Chapter 3.1 --- Data Analysis --- p.20 / Chapter 3.1.1 --- Data Collection --- p.21 / Chapter 3.1.2 --- Dataset Properties --- p.22 / Chapter 3.2 --- User Activity Prediction --- p.26 / Chapter 3.2.1 --- Definitions --- p.27 / Chapter 3.2.2 --- Category Prediction based on HMM --- p.28 / Chapter 3.2.3 --- Mixed HMM with Temporal and Spatial Covariates --- p.34 / Chapter 3.2.4 --- User Preference Modeling --- p.41 / Chapter 3.3 --- Location Prediction --- p.43 / Chapter 3.4 --- Experimental Evaluation --- p.45 / Chapter 3.4.1 --- Data Preparation --- p.46 / Chapter 3.4.2 --- Category Prediction --- p.47 / Chapter 3.4.3 --- Location Prediction --- p.51 / Chapter 3.5 --- Summary --- p.58 / Chapter 4 --- A Partition Approach to Scalable Influence Maximization in Location-based Social Networks --- p.60 / Chapter 4.1 --- Problem definition --- p.60 / Chapter 4.2 --- Influence probability --- p.62 / Chapter 4.2.1 --- Base model --- p.62 / Chapter 4.2.2 --- Distance and similarity model --- p.65 / Chapter 4.2.3 --- Location entropy model --- p.72 / Chapter 4.3 --- Partition approach --- p.74 / Chapter 4.4 --- Evaluation --- p.79 / Chapter 4.4.1 --- Data preparation --- p.79 / Chapter 4.4.2 --- Precision evaluation --- p.80 / Chapter 4.4.3 --- Influence spread evaluation --- p.83 / Chapter 4.4.4 --- Running time --- p.86 / Chapter 4.5 --- Summary --- p.88 / Chapter 5 --- Conclusion --- p.90 / Bibliography --- p.93
6

Innovation and its influence in LBS industry : Jiepang in China

Ou, Yang, Zijian, Li January 2012 (has links)
Abstract Title: Innovation and its influence of LBS company: Jiepang in China Level: Final assignment for Master of Business Administration   Author: Yang OU, Zijian LI   Supervisor: Maria. Fregidou-Malama   Date: 2012-June   Aim: Chinese firms desire to win the market, and they should consider innovation. The aim of the study is to explore the effects of innovation for LBS firm to gain success in China. Method: The main research method is case study. Jiepang as our case company is a LBS firm in China. And we interview two persons from different department, and one is its co-founder. Result & Conclusions: Innovative action and behavior must cover whole organization, all employees should be participant. In China, LBS is a rising industry, but LBS firms face to many threats from competitors and substitutes too. Thereby in order to survive in the market and gain success, innovation is a very important strategy for LBS firm, but not the unique method.       Suggestions for future research: Open innovation process is becoming a hot topic currently, so how to innovate with customer or user, how to cooperate with them? And if the data collection can take from multi-cases, it would be make research result more convincing.         Contribution of the thesis: In this study, we introduce and popularize a new industry, LBS in China. And we give a deeper understanding of the importance of innovation and how innovation can improve the competitiveness of the company in this industry.
7

Hierarchical Cell-Structured Routing Scheme with GPS for Mobile Ad Hoc Networks

Huang, Shih-kai 01 February 2010 (has links)
Many location-based routing protocols have been developed recently, and have been demonstrated to be scalable and efficient for packet routing in mobile ad hoc networks. Using location-based routing requires that a node obtains the node position with which it wants to communicate. This task is generally achieved by a location service. This work presents a novel routing protocol, called Hierarchical Cell-Structured Routing (HCR) Scheme, with a location service. The network area is divided into a number of regular triangular regions, called cells. The nodes forward the packets by some chosen cells, and are classified to be three level hierarchical structures. The hierarchical approach of HCR makes it especially suitable for high network density. Moreover, the traffic loads in HCR are shared by all nodes rather than just by some specific nodes, thus the overhead is reduced at high traffic loads. Simulation results indicate that HCR has better performance than Location-Aid Routing (LAR), in terms of packet delivery ratio, end-to-end delay and overhead in high traffic load.
8

A filter-based protocol for continuous queries over imprecise locationdata

Jin, Yifan, 金一帆 January 2012 (has links)
In typical location-based services (LBS), moving objects (e.g., GPS-enabled mobile phones) report their locations through a wireless network. An LBS server can use the location information to answer various types of continuous queries, e.g., \Give me the ID of a battalion which is the closest to a military base within the next hour." Due to hardware limitations, location data reported by the moving objects are often uncertain. In this paper, we study efficient methods for the execution of Continuous Possible Nearest Neighbor Query (CPoNNQ) that accesses imprecise location data. A CPoNNQ is a standing query (which is active during a period of time) such that, at any time point, all moving objects that have non-zero probabilities of being the nearest neighbor of a given query point are reported. To handle the continuous nature of a CPoNNQ, a simple solution is to require moving objects to continuously report their locations to the LBS server, which evaluates the query at every time step. To save communication bandwidth and mobile devices' batteries, we develop two filter-based protocols for CPoNNQ evaluation. Our protocols install filter bounds" on moving objects, which suppress unnecessary location reporting and communication between the server and the moving objects. Through extensive experiments, we show that our protocols can effectively reduce communication and energy costs while maintaining a high query quality. / published_or_final_version / Computer Science / Master / Master of Philosophy
9

Spatial and temporal pricing support for consumer services

Ruedin, Joshua Charles 07 November 2011 (has links)
Consumer acceptance of buying goods and services online via the Internet is growing, although e-ecommerce has been mostly a mirror of traditional methods of pricing transactions – fixed price or auctions. The proliferation of personal mobile devices with pervasive Internet access and localization capability means a richer set of pricing parameters can be used. Allowing buyers and sellers to more explicitly price requests and filter offers, including information about time and place, allows for better transaction results for both parties. This paper examines the impacts of including the time and place of performance of a service as part of the price. A system for implementation is proposed, a simulation of the system is evaluated, and the results presented. / text
10

Human urban mobility in location-based social networks : analysis, models and applications

Noulas, Anastasios January 2013 (has links)
No description available.

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