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2012

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Articles 11401 - 11430 of 12196

Full-Text Articles in Physical Sciences and Mathematics

Comparisons Of Observed And Modeled Oh And Ho2 Concentrations During The Ambient Measurement Period Of The Ho(X)Comp Field Campaign, Y. Kanaya, A. Hofzumahaus, H. -P. Dorn, T. Brauers, H. Fuchs, F. Holland Jan 2012

Comparisons Of Observed And Modeled Oh And Ho2 Concentrations During The Ambient Measurement Period Of The Ho(X)Comp Field Campaign, Y. Kanaya, A. Hofzumahaus, H. -P. Dorn, T. Brauers, H. Fuchs, F. Holland

USF St. Petersburg campus Faculty Publications

A photochemical box model constrained by ancillary observations was used to simulate OH and HO2 concentrations for three days of ambient observations during the HO(x)Comp field campaign held in Julich, Germany in July 2005. Daytime OH levels observed by four instruments were fairly well reproduced to within 33% by a base model run (Regional Atmospheric Chemistry Mechanism with updated isoprene chemistry adapted from Master Chemical Mechanism ver. 3.1) with high R-2 values (0.72-0.97) over a range of isoprene (0.3-2 ppb) and NO (0.1-10 ppb) mixing ratios. Daytime HO2(*) levels, reconstructed from the base model results taking into account the sensitivity …

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Crystal Structure Of Graphite Under Room-Temperature Compression And Decompression, Yuejian Wang, Joseph E. Panzik, Boris Kiefer, Kanani K. M. Lee Jan 2012

Crystal Structure Of Graphite Under Room-Temperature Compression And Decompression, Yuejian Wang, Joseph E. Panzik, Boris Kiefer, Kanani K. M. Lee

School of Geosciences Faculty and Staff Publications

Recently, sophisticated theoretical computational studies have proposed several new crystal structures of carbon (e.g., bct-C4, H-, M-, R-, S-, W-, and Z-carbon). However, until now, there lacked experimental evidence to verify the predicted high-pressure structures for cold-compressed elemental carbon at least up to 50 GPa. Here we present direct experimental evidence that this enigmatic high-pressure structure is currently only consistent with M-carbon, one of the proposed carbon structures. Furthermore, we show that this phase transition is extremely sluggish, which led to the observed broad x-ray diffraction peaks in previous studies and hindered the proper identification of the post-graphite phase in …

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Vapor-Liquid Phase Equilibria Using Monte Carlo Wang-Landau Simulations, Tsvetan Aleksandrov Jan 2012

Vapor-Liquid Phase Equilibria Using Monte Carlo Wang-Landau Simulations, Tsvetan Aleksandrov

Theses and Dissertations

The experimental determination of the critical point of metals is inherently connected with difficulties of measuring large temperatures and pressures. On the other hand, that of straight alkane chains larger than ten carbon atoms and branched chains larger than eight atoms is burdensome due to decomposition of the molecules while in the vapor phase. Therefore molecular simulations stand as an appropriate alternative for determining the critical point and phase coexistence properties of these fluids. Most simulation methods that are apt for this task rely on particles insertion and deletion moves that can significantly complicate the simulation, since high density in …

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Implementation Of A Middleware Architecture For Collaboration Among Mobile Devices In Opportunistic Networks., Samaya Madhavan Jan 2012

Implementation Of A Middleware Architecture For Collaboration Among Mobile Devices In Opportunistic Networks., Samaya Madhavan

Computer Science and Engineering Theses

Opportunistic networks provide a viable platform for mobile communications due to the ubiquity of smart phones. These networks are characterized by lack of end to-end reliable connections. In such networks, establishing collaboration among nodes is a challenge. In this thesis, a middleware architecture for opportunistic communication and collaboration has been designed, developed, and implemented. The middleware architecture supports a protocol for efficiently exchanging information between mobile nodes during an opportunistic contact. Message formats for differentiating the various kinds of messages that will be transferred across the network are defined to maintain consistency and reduce redundancy. The architecture consists of several …

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Subrosa 2 : An Experimental Evaluation Of Timing Analysis Attacks And Defenses In Anonymity Systems, Payap Sirinam Jan 2012

Subrosa 2 : An Experimental Evaluation Of Timing Analysis Attacks And Defenses In Anonymity Systems, Payap Sirinam

Computer Science and Engineering Theses

A circuit-based low-latency anonymous communication service such as Tor helps Internet users hide their IP addresses and thereby conceal their identities when communicating online. However, this kind of service is vulnerable to timing analysis attacks that can discern the relationship between incoming and outgoing messsages in order to find correlations between them. The attacker can use this information to reveal the idenity of the internet users without knowing the IP addresses concealed in the anonymous communication services.Dependent link padding (DLP) is a scheme propsed to enable anonymity systems to resist these attacks. However, DLP adds high overhead from dummy packets …

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System For Interpretation Of Reviewer Feedback On Social Web, Shrikant Desai Jan 2012

System For Interpretation Of Reviewer Feedback On Social Web, Shrikant Desai

Computer Science and Engineering Theses

The increasing popularity of social media web sites such as Amazon, Yelp and others has influenced our online decision making. Before making selection decisions on movies and restaurants, we investigate its reviewer feedback. Social media web sites provide reviewer feedback in the form of ratings, tags, and user reviews. However, overwhelming feedback details will leave the user in a quandary as to decide whether the item is desirable or not. Potential buyers either make a snap judgment based on the aggregate ratings/tags or spend a lot of time in reading reviews.In this thesis, we build a system that can analyse …

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Learning Partially Observable Markov Decision Processes Using Abstract Actions, Hamed Janzadeh Jan 2012

Learning Partially Observable Markov Decision Processes Using Abstract Actions, Hamed Janzadeh

Computer Science and Engineering Theses

Transfer learning and Abstraction are among the new and most interesting research topics in AI and address the use of learned knowledge to improve learning performance in subsequent tasks. While there has been significant recent work on this topic in fully observable domain, it has been less studied for Partially Observable MDPs. This thesis addresses the problem of transferring skills from the previous experiences in POMDP models using high-level actions (Options) in two different kind of algorithms: value iteration and expectation maximization. To do this, this thesis first proves that the optimal value function remains piecewise-linear and convex when policies …

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Selective Grouping Algorithm For Low Latency Anonymous Systems, Vishal Gupta Jan 2012

Selective Grouping Algorithm For Low Latency Anonymous Systems, Vishal Gupta

Computer Science and Engineering Theses

Low latency anonymous communications are prone to timing analysis attacks. It is a technique by which the adversary can de-anonymize the user by correlating packet timing patterns. A recent proposal to stop these attacks is called Dependent Link padding. However, it creates high dummy packets overhead in the network. In this work we propose selective grouping, a padding scheme that protects users in an anonymity system from those attacks with minimal overhead. The aim is to decrease overhead by dividing users in different groups while maintaining good anonymity. The key idea of our approach is to group clients with similar …

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Shaping And Maintenance Of Low-Latency Anonymity Systems, Harsha Doreswamy Jan 2012

Shaping And Maintenance Of Low-Latency Anonymity Systems, Harsha Doreswamy

Computer Science and Engineering Theses

Surveillance of users on the Internet is growing. This makes it increasingly important to protect users' identity when they communicate online, especially for users like journalists, whistleblowers, and military officials. Anonymity systems can conceal users' identities and provide anonymity for their online activities. Low-latency anonymity systems like Tor are designed to provide support for applications like Web browsing, video streaming, and online chat. To make the commutation between source and destination unlinkable, Tor routes all the traffic through three Tor relays, which are spread across the globe. These three relays are usually chosen without considering the delay to get from …

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Choices And Consequences: A Game-Based Risky Behavior Prevention Program, Amanda Michelle Vines Jan 2012

Choices And Consequences: A Game-Based Risky Behavior Prevention Program, Amanda Michelle Vines

Computer Science and Engineering Theses

Serious games have been defined as a mental contest played with a computer in accordance to specific rules that use entertainment to further government or corporate training, education, health, public policy and strategic communication objectives. There have been various studies done to gauge the effectiveness of serious games to teach and engage. In collaboration with professors in social work and computer science, we have designed a multiplayer, social, serious game called Choices and Consequences (C&C) in an effort to better reach the audience of pre-teens and teens in order to reduce the risk taking behaviors of youth today. The game …

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Reducing The Complexity Of Reinforcement Learning In Pomdps By Decomposition Into Decision And Perceptual Processes, Rasool Fakoor Jan 2012

Reducing The Complexity Of Reinforcement Learning In Pomdps By Decomposition Into Decision And Perceptual Processes, Rasool Fakoor

Computer Science and Engineering Theses

Markov Decision Processes (MDPs) and Partially Observable Markov Decision Processes (POMDPs) are very powerful and general frameworks to model decision and decision learning tasks in a wide range of problem domains. As a result, they are widely used in complex and real-world situations such as robot control tasks. However, the modeling power and generality of the frameworks comes at a cost in that the complexity of the underlying models and corresponding algorithms grows dramatically as the complexity of the task domain increases. To address this , this work presents an integrated and adaptive approach that attempts to reduce the complexity …

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Measurements Of A Latency-Biased Expander Topology In The Tor Anonymity System, Subhasish Dutta Chowdhuri Jan 2012

Measurements Of A Latency-Biased Expander Topology In The Tor Anonymity System, Subhasish Dutta Chowdhuri

Computer Science and Engineering Theses

Anonymous communication systems protect the privacy of their users by hiding who is communicating with whom. With the widespread use of the Internet, anonymity systems are all the more essential to support applications having strong privacy requirements such as intelligence gathering, military communications, or e-voting protocols. Anonymity systems must balance security and performance to remain popular with their users. In this work, we perform measurements on anonymity systems to improve their performance. We use the Vivaldi network coordinate system to efficiently map out the relative delays between hosts. Using this data, we create an overlay expander network topology that is …

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Point Of Gaze Applications For Assistive Interaction, Jonathan Walter Rich Jan 2012

Point Of Gaze Applications For Assistive Interaction, Jonathan Walter Rich

Computer Science and Engineering Theses

Eye tracking has many useful applications in human-machine interfaces and assistive technologies. Traditional input methods, such as the keyboard and mouse, are not practical in certain situations and can be completely ineffective for users with physical disabilities. Since many computing interfaces contain a strong visual component, it follows that knowledge of the user's point of gaze (PoG) can be extremely useful. Several approaches to PoG tracking have been described with various results and associated costs. Commercially available tracking devices have proven to be very useful for some disabled users, though often the systems can be cost prohibitive. Many computing applications …

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Development Of A Detached Vital Sign Home Monitoring Management System, Anderson John Jan 2012

Development Of A Detached Vital Sign Home Monitoring Management System, Anderson John

Computer Science and Engineering Theses

Patients coping with chronic illnesses are often inconvenienced with routine doctor visits for the sole purpose of conducting basic vital sign monitoring. Such visits tend to be disruptive, and are more so when the patient requires a lengthy commute or has a mobility disability. As technology progresses, advances in low powered integrated circuits and network connectivity has opened the doors to a new world of remote patient monitoring. This thesis explores the possibility of using low powered technology to develop a patient monitoring system that's completely detached, thus allowing patients to move around their homes while the monitoring continues. We …

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An Experiment In Developing Small Mobile Phone Applications Comparing On-Phone To Off-Phone Development, Tuan Anh Nguyen Jan 2012

An Experiment In Developing Small Mobile Phone Applications Comparing On-Phone To Off-Phone Development, Tuan Anh Nguyen

Computer Science and Engineering Theses

TouchDevelop represents a radically new mobile application development model, as TouchDevelop enables mobile application development on a mobile device. I.e., with TouchDevelop, the task of programming say a Windows Phone is shifted from the desktop computer to the mobile phone itself. We describe a first experiment on independent, non-expert subjects to compare programmer productivity using TouchDevelop vs. using a more traditional approach to mobile application development.

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Prominent Streaks Discovery On Blog Articles, Jijo John Philip Jan 2012

Prominent Streaks Discovery On Blog Articles, Jijo John Philip

Computer Science and Engineering Theses

We are surrounded by data in various forms such as instant messages, Twitter tweets, Facebook status updates, news, media, blogs and much more. Extracting meaning from such a massive collection of unstructured data would lead to interesting stories. Examples of such stories can be ``\emph{Who was the most popular actor in a particular month}''or ``\emph{Which diseases were people most concerned about in year 2008}''. In this thesis, we propose to discover popular entities mentioned in blog articles based on the concept of prominent streak. Given a sequence of values for a named entity (e.g., a person, a place, etc.), where …

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On Feasibility Of Fingerprinting Wireless Sensor Nodes Using Physical Properties, Xiaowei Mei Jan 2012

On Feasibility Of Fingerprinting Wireless Sensor Nodes Using Physical Properties, Xiaowei Mei

Computer Science and Engineering Theses

Fingerprinting wireless devices using physical properties has been recently suggested as an alternative for device identification and authentication. It has been found that the clock skew caused by the frequency discrepancy of the quartz crystals in different devices can be used as a reliable source for fingerprinting. Researchers have studied the application of the clock skew-based fingerprinting in sensor networks and claimed that it can detect fake identities, wormholes, and node replicas. However, the study in this paper draws a completely opposite conclusion, i.e., the clock skew of sensor nodes can be easily forged by adversaries to evade the detection. …

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Pushpop: A Card Game, Vishal Subramani Jan 2012

Pushpop: A Card Game, Vishal Subramani

Computer Science and Engineering Theses

In this thesis we have designed and implemented an Android card game called PushPop. This game is meant to stimulate the interest of kids in math learning. The Android game has cards with mathematical signs instead of the traditional suits. To reach the goal kids have to perform a lot of mathematical operations which helps them learn maths in a fun and effective way. A study was made to classify PushPop into the various games under the research umbrella of Game Theory. After the analysis we conclude that PushPop is a non-co-operative, symmetric, non-zero sum, simultaneously and imperfect information game …

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Comparing Web Application Scanners For Xss Attacks, Dengfeng Xia Jan 2012

Comparing Web Application Scanners For Xss Attacks, Dengfeng Xia

Computer Science and Engineering Theses

As software industry is paying increasing attention to web application security, various testing tools with black box testing feature have been developed. To better evaluate their performance, researchers have made efforts in several ways. Since XSS attack is one of the major attacks which can bring severe damages to victims, it is meaningful to pay specific attention to its testing process. However, many web application scanner evaluation projects make comparisons about various vulnerability types, and they are not dedicated to XSS issues enough. Their evaluations either use vulnerable applications in real life, or use test cases created by themselves, and …

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Shaping Network Topology For Privacy And Performance, Md Monjurul Hasan Jan 2012

Shaping Network Topology For Privacy And Performance, Md Monjurul Hasan

Computer Science and Engineering Theses

Anonymity systems provide privacy for Internet communication and are becoming popular. Unfortunately, users experience slow Internet connection through existing systems because paths used to route traffic are selected randomly without considering latency between nodes. In our work, we aim to design a better approach for selecting paths in anonymity systems with improved performance and without sacrificing privacy. We consider stratified topologies for our design where nodes are divided into three hops. We propose a scheme to build restricted network topologies on top of a stratified topology that maximizes throughput. First, we use Tabu Search to build latency-aware stratified restricted topologies …

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A Novel Scheme For Contact Predictions In Opportunistic Networks, Sujoy Kumar Bhattacharya Jan 2012

A Novel Scheme For Contact Predictions In Opportunistic Networks, Sujoy Kumar Bhattacharya

Computer Science and Engineering Theses

In the opportunistic network (ON) paradigm information is exchanged between two devices as they encounter each other. For such information exchange to take place the devices must know about the presence of other devices in the neighborhood. A very fundamental problem in ON is to predict the occurrence of a future opportunistic contact which is otherwise highly dynamic and unreliable. An accurate predictor which takes into account the long time history can benefit from multiple objectives. Such a predictor switches to the data transfer mode in anticipation of a contact. Also it maximizes the number of opportunistic contacts while spending …

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Control Framework Dynamic Walking Of A Bipedal Robot, Kishan Kumar Bhongale Prabhakar Prasad Jan 2012

Control Framework Dynamic Walking Of A Bipedal Robot, Kishan Kumar Bhongale Prabhakar Prasad

Computer Science and Engineering Theses

Despite significant progress in recent years, the capabilities of today's Humanoid robots still lack behind the walking abilities of humans in terms of competence, robustness, flexibility, and speed. Furthermore, unknown environmental conditions and related constraints imposed on the robot significantly increase the complexity of locomotion control and decision making for such systems, easily making planning-based approaches intractable. Part of the reason for this is that the control of a humanoid encompasses observation, processing the observed data, and decision making in terms of locomotion gait and body pose parameters. This key information derived from observations and internal robot information finally allows …

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Hydrological Visualization And Analysis System And Drought Related Feature Selection Based On Sectional Correlation Measurement, Piraporn Jangyodsuk Jan 2012

Hydrological Visualization And Analysis System And Drought Related Feature Selection Based On Sectional Correlation Measurement, Piraporn Jangyodsuk

Computer Science and Engineering Theses

Because of the larger data storage and the faster computational power, computer can process and store much finer resolution data. Aside from data analysis, data visualization is also an important task to understand the data. In this work, the Hydrological Visualization and Analysis System is developed to help both hydrologists and local people view and examine the high resolution hydrological data. Then, this data is analyzed to determine which variables are related to the change of drought condition in Arlington, Texas. A new correlation measurement method called sectional correlation is proposed and used as an objective function of the drought …

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Automatic Scheduler: A New Approach For Scheduling Rides, Amey Sudhir Bhalerao Jan 2012

Automatic Scheduler: A New Approach For Scheduling Rides, Amey Sudhir Bhalerao

Computer Science and Engineering Theses

Scheduling plays an important role in a person's life. Even computers use the concept of scheduling when it comes to processing jobs. Scheduling is important in cases normally when there is large data to process and manual scheduling is not an easy option to go for. A new concept of developing a scheduler has been discussed in this thesis. The algorithm was designed keeping in mind the Para Transit agencies that operate on federal funds to provide cheap transport service to the clients. The algorithm presented here is developed with the intention to reduce the delay faced by the client …

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Dynamic Cache Reconfiguration For Energy Optimization In Chip Multiprocessors, Gaurav Puri Jan 2012

Dynamic Cache Reconfiguration For Energy Optimization In Chip Multiprocessors, Gaurav Puri

Computer Science and Engineering Theses

Cache reconfiguration for chip multiprocessors (CMP) in order to reduce energy consumption is a challenging research problem. This thesis presents a dynamic scheme for level one cache design where the processing core can dynamically switch to a lower energy configuration. The proposed scheme is based on a heuristic that can either be executed as part of the firmware or implemented in hardware with very low additional overhead. The heuristic functions periodically after a pre-defined fixed interval for each processing core. The heuristic first examines the statistics calculated over the previous intervals and then switches the cache to an improved configuration …

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Querying Entity-Relationship Graphs By Example Tuples: Experimental Evaluation And User Study, Mahesh Gupta Jan 2012

Querying Entity-Relationship Graphs By Example Tuples: Experimental Evaluation And User Study, Mahesh Gupta

Computer Science and Engineering Theses

The World Wide Web today has evolved into a rich repository of entities where many knowledge bases containing entity-related information are directly available. Such knowledge bases are often in the form of entity-relationship graphs. To query entity-relationship graphs, users need to provide input entities, attributes and relationships by complex query graphs. To improve the usability of graph database systems, we study a novel mechanism that queriesentity-relationship graphs by example tuples. It allows users to express a query in the form of one or more tuples consisting of entities. The underlying query system automatically builds aquery graph based on the example …

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Charge Delocalization In Self-Assembled Mixed-Valence Aromatic Cation Radicals, Tushar Navale, Khushabu Thakur, Vijay Vyas, Shriya Wadumethrige, Ruchi Shukla, Sergey V. Lindeman, Rajendra Rathore Jan 2012

Charge Delocalization In Self-Assembled Mixed-Valence Aromatic Cation Radicals, Tushar Navale, Khushabu Thakur, Vijay Vyas, Shriya Wadumethrige, Ruchi Shukla, Sergey V. Lindeman, Rajendra Rathore

Chemistry Faculty Research and Publications

The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation …

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Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam Jan 2012

Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam

Electronic Theses and Dissertations

Vehicular ad hoc network (VANET) is a special case of mobile networks, where vehicles equipped with computing/communicating devices (called "smart vehicles") are the mobile wireless nodes. However, the movement pattern of these mobile wireless nodes is no more random, as in case of mobile networks, rather it is restricted to roads and streets. Vehicular networks have hybrid architecture; it is a combination of both infrastructure and infrastructure-less architectures. The direct vehicle to vehicle (V2V) communication is infrastructure-less or ad hoc in nature. Here the vehicles traveling within communication range of each other form an ad hoc network. On the other …

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Turtle Cam: Live Multimedia Interaction For Engaging Potential Visitor Population To Canaveral National Seashore, Brian Alfred Tortorelli Jan 2012

Turtle Cam: Live Multimedia Interaction For Engaging Potential Visitor Population To Canaveral National Seashore, Brian Alfred Tortorelli

Electronic Theses and Dissertations

This project expands the outreach of the Canaveral National Seashore to its visitors, potential visitors, and virtual visitors through its goals in conservancy and preservation of its natural resources. This paper is involved with the current iteration of a series of digital media projects, the Sea Turtle Nest Camera, also known as, Turtle Cam. It details how and why this project was designed to be an ongoing initiative to assist in those goals.

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Characterization And Application Of Isolated Attosecond Pulses, Michael Chini Jan 2012

Characterization And Application Of Isolated Attosecond Pulses, Michael Chini

Electronic Theses and Dissertations

Tracking and controlling the dynamic evolution of matter under the influence of external fields is among the most fundamental goals of physics. In the microcosm, the motion of electrons follows the laws of quantum mechanics and evolves on the timescale set by the atomic unit of time, 24 attoseconds. While only a few time-dependent quantum mechanical systems can be solved theoretically, recent advances in the generation, characterization, and application of isolated attosecond pulses and few-cycle femtosecond lasers have given experimentalists the necessary tools for dynamic measurements on these systems. However, pioneering studies in attosecond science have so far been limited …

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