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Full-Text Articles in Physical Sciences and Mathematics
Rethinking Privacy And Security Mechanisms In Online Social Networks, Xin Ruan
Rethinking Privacy And Security Mechanisms In Online Social Networks, Xin Ruan
Dissertations, Theses, and Masters Projects
With billions of users, Online Social Networks(OSNs) are amongst the largest scale communication applications on the Internet. OSNs enable users to easily access news from local and worldwide, as well as share information publicly and interact with friends. On the negative side, OSNs are also abused by spammers to distribute ads or malicious information, such as scams, fraud, and even manipulate public political opinions. Having achieved significant commercial success with large amount of user information, OSNs do treat the security and privacy of their users seriously and provide several mechanisms to reinforce their account security and information privacy. However, the …
The Impact Of Surface Normals On Appearance, Kathleen Dorothy Moore
The Impact Of Surface Normals On Appearance, Kathleen Dorothy Moore
Dissertations, Theses, and Masters Projects
The appearance of an object is the result of complex light interaction with the object. Beyond the basic interplay between incident light and the object's material, a multitude of physical events occur between this illumination and the microgeometry at the point of incidence, and also beneath the surface. A given object, made as smooth and opaque as possible, will have a completely different appearance if either one of these attributes - amount of surface mesostructure (small-scale surface orientation) or translucency - is altered. Indeed, while they are not always readily perceptible, the small-scale features of an object are as important …
Enhancing The Sensing Capabilities Of Mobile And Embedded Systems, Daniel George Graham
Enhancing The Sensing Capabilities Of Mobile And Embedded Systems, Daniel George Graham
Dissertations, Theses, and Masters Projects
In this work, we aim to develop new sensors and sensing platforms that facilitate the development of new mobile and embedded devices. Mobile and embedded devices have become an integral part of our everyday lives and the sensing capabilities of these devices have improved throughout the years. Developing new and innovative sensors and sensing platforms will provide the building blocks for developing new sensing systems. In an effort to facilitate these innovations we have developed two new in-air sonar sensors and a new reconfigurable sensing platform. The first in-air sonar sensor is designed for ranging applications and uses the phone's …
Methods For Estimating The Diagonal Of Matrix Functions, Jesse Harrison Laeuchli
Methods For Estimating The Diagonal Of Matrix Functions, Jesse Harrison Laeuchli
Dissertations, Theses, and Masters Projects
Many applications such as path integral evaluation in Lattice Quantum Chromodynamics (LQCD), variance estimation of least square solutions and spline ts, and centrality measures in network analysis, require computing the diagonal of a function of a matrix, Diag(f(A)) where A is sparse matrix, and f is some function. Unfortunately, when A is large, this can be computationally prohibitive. Because of this, many applications resort to Monte Carlo methods. However, Monte Carlo methods tend to converge slowly. One method for dealing with this shortcoming is probing. Probing assumes that nodes that have a large distance between them in the graph of …
Protecting Web Contents Against Persistent Crawlers, Shengye Wan
Protecting Web Contents Against Persistent Crawlers, Shengye Wan
Dissertations, Theses, and Masters Projects
Web crawlers have been developed for several malicious purposes like downloading server data without permission from website administrator. Armored stealthy crawlers are evolving against new anti-crawler mechanisms in the arms race between the crawler developers and crawler defenders. In this paper, we develop a new anti-crawler mechanism called PathMarker to detect and constrain crawlers that crawl content of servers stealthy and persistently. The basic idea is to add a marker to each web page URL and then encrypt the URL and marker. By using the URL path and user information contained in the marker as the novel features of machine …
Supporting Evolution And Maintenance Of Android Apps, Mario Linares-Vasquez
Supporting Evolution And Maintenance Of Android Apps, Mario Linares-Vasquez
Dissertations, Theses, and Masters Projects
Mobile developers and testers face a number of emerging challenges. These include rapid platform evolution and API instability; issues in bug reporting and reproduction involving complex multitouch gestures; platform fragmentation; the impact of reviews and ratings on the success of their apps; management of crowd-sourced requirements; continuous pressure from the market for frequent releases; lack of effective and usable testing tools; and limited computational resources for handheld devices. Traditional and contemporary methods in software evolution and maintenance were not designed for these types of challenges; therefore, a set of studies and a new toolbox of techniques for mobile development are …
Enhancing Mobile Device System Using Information From Users And Upper Layers, Dung Nguyen Tien
Enhancing Mobile Device System Using Information From Users And Upper Layers, Dung Nguyen Tien
Dissertations, Theses, and Masters Projects
Despite the rapid hardware upgrades, a common complaint among smartphone owners is the poor battery life. to many users, being required to charge the smartphone after a single day of moderate usage is unacceptable. Moreover, current smartphones suffer various unpredictable delays during operation, e.g., when launching an app, leading to poor user experience. In this dissertation, we provide solutions that enhance systems on portable devices using information obtained from their users and upper layers on the I/O path. First, we provide an experimental study on how storage I/O path upper layers affect power levels in smartphones, and introduce energy-efficient approaches …
Managing Micro Vms In Amazon Ec2, Jiawei Wen
Managing Micro Vms In Amazon Ec2, Jiawei Wen
Dissertations, Theses, and Masters Projects
Micro instances (t1.micro) are the class of Amazon EC2 virtual machines (VMs) offering the lowest operational costs for applications with short bursts in their CPU requirements. as processing proceeds, EC2 throttles CPU capacity of micro instances in a complex, unpredictable, manner. This thesis aims at making micro instances more predictable and efficient to use. First, we present a characterization of EC2 micro instances that evaluates the complex interactions between cost, performance, idleness and CPU throttling. Next, we define adaptive algorithms to manage CPU consumption by learning the workload characteristics at runtime and by injecting idleness to diminish host-level throttling. Experimental …
Algorithms For Large Scale Problems In Eigenvalue And Svd Computations And In Big Data Applications, Lingfei Wu
Algorithms For Large Scale Problems In Eigenvalue And Svd Computations And In Big Data Applications, Lingfei Wu
Dissertations, Theses, and Masters Projects
As ”big data” has increasing influence on our daily life and research activities, it poses significant challenges on various research areas. Some applications often demand a fast solution of large, sparse eigenvalue and singular value problems; In other applications, extracting knowledge from large-scale data requires many techniques such as statistical calculations, data mining, and high performance computing. In this dissertation, we develop efficient and robust iterative methods and software for the computation of eigenvalue and singular values. We also develop practical numerical and data mining techniques to estimate the trace of a function of a large, sparse matrix and to …
Security Supports For Cyber-Physical System And Its Communication Networks, Zhengrui Qin
Security Supports For Cyber-Physical System And Its Communication Networks, Zhengrui Qin
Dissertations, Theses, and Masters Projects
A cyber-physical system (CPS) is a sensing and communication platform that features tight integration and combination of computation, networking, and physical processes. In such a system, embedded computers and networks monitor and control the physical processes through a feedback loop, in which physical processes affect computations and vice versa. In recent years, CPS has caught much attention in many different aspects of research, such as security and privacy. In this dissertation, we focus on supporting security in CPS and its communication networks. First, we investigate the electric power system, which is an important CPS in modern society. as crucial and …
Workload Interleaving With Performance Guarantees In Data Centers, Feng Yan
Workload Interleaving With Performance Guarantees In Data Centers, Feng Yan
Dissertations, Theses, and Masters Projects
In the era of global, large scale data centers residing in clouds, many applications and users share the same pool of resources for the purposes of reducing energy and operating costs, and of improving availability and reliability. Along with the above benefits, resource sharing also introduces performance challenges: when multiple workloads access the same resources concurrently, contention may occur and introduce delays in the performance of individual workloads. Providing performance isolation to individual workloads needs effective management methodologies. The challenges of deriving effective management methodologies lie in finding accurate, robust, compact metrics and models to drive algorithms that can meet …
Security And Privacy For Ubiquitous Mobile Devices, Edmund Novak
Security And Privacy For Ubiquitous Mobile Devices, Edmund Novak
Dissertations, Theses, and Masters Projects
We live in a world where mobile devices are already ubiquitous. It is estimated that in the United States approximately two thirds of adults own a smartphone, and that for many, these devices are their primary method of accessing the Internet. World wide, it is estimated that in May of 2014 there were 6.9 billion mobile cellular subscriptions, almost as much as the world population. of these 6.9 billion, approximately 1 billion are smart devices, which are concentrated in the developed world. In the developing world, users are moving from feature phones to smart devices as a result of lower …
Understanding Security Threats In Cloud, Zhang Xu
Understanding Security Threats In Cloud, Zhang Xu
Dissertations, Theses, and Masters Projects
As cloud computing has become a trend in the computing world, understanding its security concerns becomes essential for improving service quality and expanding business scale. This dissertation studies the security issues in a public cloud from three aspects. First, we investigate a new threat called power attack in the cloud. Second, we perform a systematical measurement on the public cloud to understand how cloud vendors react to existing security threats. Finally, we propose a novel technique to perform data reduction on audit data to improve system capacity, and hence helping to enhance security in cloud. In the power attack, we …