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University of Nebraska - Lincoln

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Articles 781 - 810 of 1069

Full-Text Articles in Computer Engineering

Wireless Embedded Smart Cameras: Performance Analysis And Their Application To Fall Detection For Eldercare., Alvaro Pinto Jul 2011

Wireless Embedded Smart Cameras: Performance Analysis And Their Application To Fall Detection For Eldercare., Alvaro Pinto

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Wireless Embedded Smart Camera Networks has received a lot of attention from academia and industry because they are small in size and easy to deploy, and they offer a multitude of attractive applications. They can be used for embedded single unit applications, or can be networked for multi-camera applications.

We first analyze three different operation scenarios for a wireless vision sensor network wherein different levels of local processing is performed. A detailed quantitative comparison of three operation scenarios are presented in terms of energy consumption and latency. This quantitative analysis provides the motivation for performing high-level local processing and decision …


Molecular Dynamics Simulation Based On Hadoop Mapreduce, Chen He Jul 2011

Molecular Dynamics Simulation Based On Hadoop Mapreduce, Chen He

School of Computing: Dissertations, Theses, and Student Research

Molecular Dynamics (MD) simulation is a computationally intensive application used in multiple fields. It can exploit a distributed environment due to inherent computational parallelism. However, most of the existing implementations focus on performance enhancement. They may not provide fault-tolerance for every time-step.

MapReduce is a framework first proposed by Google for processing huge amounts of data in a distributed environment. The simplicity of the programming model and fault- tolerance for node failure during run-time make it very popular not only for commercial applications but also in scientific computing.

In this thesis, we develop a novel communication-free and each time-step fault- …


Real-Time Divisible Load Scheduling For Cluster Computing, Anwar Mamat Jul 2011

Real-Time Divisible Load Scheduling For Cluster Computing, Anwar Mamat

School of Computing: Dissertations, Theses, and Student Research

Cluster computing has become an important paradigm for solving large-scale problems. However, as the size of a cluster increases, so does the complexity of resource management and maintenance. Therefore, automated performance control and re- source management are expected to play critical roles in sustaining the evolution of cluster computing. The current cluster scheduling practice is similar in sophistication to early supercomputer batch scheduling algorithms, and no consideration is given to desired quality-of-service (QoS) attributes. To fully avail the power of computational clusters, new scheduling algorithms that provides high performance, QoS assurance, fault-tolerance, energy savings and streamlined management of the cluster …


Enhancement Of Optical Emission From Laser-Induced Plasmas By Combined Spatial And Magnetic Confinement, L. B. Guo, W. Hu, B. Y. Zhang, X. N. He, C. M. Li, Y. S. Zhou, Z. X. Cai, X. Y. Zeng, Yongfeng Lu Jul 2011

Enhancement Of Optical Emission From Laser-Induced Plasmas By Combined Spatial And Magnetic Confinement, L. B. Guo, W. Hu, B. Y. Zhang, X. N. He, C. M. Li, Y. S. Zhou, Z. X. Cai, X. Y. Zeng, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Within the past decades, laser-induced breakdown spectroscopy (LIBS) has become a well-established and powerful optical emission spectroscopy (OES) analytical technique [1–5]. As a useful analytical tool, LIBS is used extensively in various areas such as remote detection, hostile environment monitoring, and cultural heritage conservation [6–10]. Researchers are paying more attention to LIBS as a diagnostic method for elemental analysis as it is characterized by fast, real-time, in situ, low invasiveness, and multi-elemental diagnosis, normally without the need for sample preparation [11,12]. However, one of its major drawbacks is its low sensitivity, which seriously hinders further improving the limit of detection …


Apparatus For Dispensing Material, Peter Werner Sutter, Eli Anguelova Sutter Jul 2011

Apparatus For Dispensing Material, Peter Werner Sutter, Eli Anguelova Sutter

Department of Electrical and Computer Engineering: Faculty Publications

An apparatus capable of dispensing drops of material with volumes on the order of Zeptoliters is described. In some embodiments of the inventive pipette the size of the droplets so dispensed is determined by the size of a hole, or channel, through a carbon shell encapsulating a reservoir that contains material to be dispensed. The channel may be formed by irradiation with an electronbeam or other high-energy beam capable of focusing to a spot size less than about 5 nanom eters. In some embodiments, the dispensed droplet remains attached to the pipette by a small thread of material, an atomic …


A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio Jul 2011

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …


A Reservation-Based Smart Parking System, Hongwei Wang Jul 2011

A Reservation-Based Smart Parking System, Hongwei Wang

School of Computing: Dissertations, Theses, and Student Research

In metropolitan areas, parking management influences drivers search time and cost for parking spaces, parking revenue, and traffic congestion. The wide deployment of wireless parking meters with sensing and communications capabilities allows the parking authority to monitor the state of each parking space in real time and optimize the parking management.

In this thesis, we study state-of-the-art parking policies in smart parking systems, and show that the smart parking system needs to be "smarter". Our design goals of the smart parking systems include: (1) simplify the operations of parking systems, (2) improve drivers' satisfaction, (3) increase parking revenue, and (4) …


Quantifying Performance Of Cooperative Diversity Using The Sampling Property Of A Delta Function, Won Mee Jang Jul 2011

Quantifying Performance Of Cooperative Diversity Using The Sampling Property Of A Delta Function, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, we present a simple approach to evaluating the performance of amplify-and-forward cooperative diversity. The �-function can be asymptotically reduced to a delta (impulse) function. We extend the result to cooperative networks in fading channels. The proposed approach introduces a simple technique to evaluate the performance of complex networks by sampling.


Study Of Cellular Phone Detection Techniques, Nicholas W. Scott Jun 2011

Study Of Cellular Phone Detection Techniques, Nicholas W. Scott

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

This thesis studies techniques for detecting cellular phones.  It examines existing technology currently available on the open market, an existing design that utilizes mostly discrete components, and a design approach using a down converter in conjunction with a bandpass filter.

The existing technologies available on the open market are examined and discussed. These technologies are not adequate, because they are inaccurate and expensive.

The first signal detection technique, an existing design utilizing discrete components is difficult to implement.  They are very affordable to construct, but require precision tuning.  This design is analyzed and found to be inaccurate.

The second signal …


Generation Of High-Temperature And Low-Density Plasmas For Improved Spectral Resolutions In Laser-Induced Breakdown Spectroscopy, X. N. He, W. Hu, C. M. Li, L. B. Guo, Yongfeng Lu May 2011

Generation Of High-Temperature And Low-Density Plasmas For Improved Spectral Resolutions In Laser-Induced Breakdown Spectroscopy, X. N. He, W. Hu, C. M. Li, L. B. Guo, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Improved spectral resolutions were achieved in laser-induced breakdown spectroscopy (LIBS) through generation of high-temperature and low-density plasmas. A first pulse from a KrF excimer laser was used to produce particles by perpendicularly irradiating targets in air. A second pulse from a 532 nm Nd:YAG laser was introduced parallel to the sample surface to reablate the particles. Optical scattering from the first-pulse plasmas was imaged to elucidate particle formation in the plasmas. Narrower line widths (full width at half maximums: FWHMs) and weaker self-absorption were observed from time-integrated LIBS spectra. Estimation of plasma temperatures and densities indicates that high temperature and …


Campus Grids: A Framework To Facilitate Resource Sharing, Derek J. Weitzel May 2011

Campus Grids: A Framework To Facilitate Resource Sharing, Derek J. Weitzel

School of Computing: Dissertations, Theses, and Student Research

It is common at research institutions to maintain multiple clusters. These might fulfill different needs and policies, or represent different owners or generations of hard- ware. Many of these clusters are under utilized while researchers at other departments may require these resources. This may be solved by linking clusters with grid mid- dleware. This thesis describes a distributed high throughput computing framework to link clusters without changing security or execution environments. The framework initially keeps jobs local to the submitter, overflowing if necessary to the campus, and regional grid. The framework is implemented spanning two campuses at the Holland Computing …


Exploration Of Spatial Diversity In Multi-Antenna Wireless Communication Systems, Shichuan Ma May 2011

Exploration Of Spatial Diversity In Multi-Antenna Wireless Communication Systems, Shichuan Ma

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

With increasing demand on wireless internet and personal multimedia, the data rate of wireless communications is expected to increase dramatically. Future wireless networks face challenges of supporting data rates higher than one gigabits per second. Among various technologies, multi-antennas, also known as multiple-input multiple-output (MIMO), are undoubtedly the most promising to enable higher data rates. By employing the extra degrees of freedom in the spatial domain, multi-antenna techniques enhance the wireless communication systems through array gain, spatial diversity, and spatial multiplexing. Although multi-antenna systems have been utilized for more than ten years, a thorough analysis of various aspects of multi-antenna …


Protein Structure-Based Method For Identification Of Horizontal Gene Transfer In Bacteria, Swetha Billa May 2011

Protein Structure-Based Method For Identification Of Horizontal Gene Transfer In Bacteria, Swetha Billa

School of Computing: Dissertations, Theses, and Student Research

Horizontal Gene Transfer is defined as the movement of genetic material from one strain of species to another. Bacteria, being an asexual organism were always believed to transfer genes vertically. But recent studies provide evidence that shows bacteria can also transfer genes horizontally.

HGT plays a major role in evolution and medicine. It is the major contributor in bacterial evolution, enabling species to acquire genes to adapt to the new environments. Bacteria are also believed to develop drug resistance to antibiotics through the phenomenon of HGT. Therefore further study of HGT and its implications is necessary to understand the effects …


Ontology For Psychophysiological Dysregulation Of Anger/Aggression, Swathi Vasanthapuram May 2011

Ontology For Psychophysiological Dysregulation Of Anger/Aggression, Swathi Vasanthapuram

School of Computing: Dissertations, Theses, and Student Research

The advancement of Information Technology in the last four decades led to the use of computers in medicine. A new area called Medical Informatics has emerged. This area comprises the application of IT to healthcare with the aim of creating tools that help healthcare personnel diagnose and treat patients more accurately and efficiently. IT not only provides tools for storing, integrating, and updating patient information base but also for processing information efficiently. One of such tools is a Clinical Decision Support System. Ontologies are an integral part of clinical decision support systems because they help formalize and integrate domain knowledge. …


Understanding User Generated Content Characteristics : A Hot-Event Perspective, Miao Wang, Guodong Li, Jie Feng, Lisong Xu, Byrav Ramamurthy, Wei Li, Xiaohong Guan Apr 2011

Understanding User Generated Content Characteristics : A Hot-Event Perspective, Miao Wang, Guodong Li, Jie Feng, Lisong Xu, Byrav Ramamurthy, Wei Li, Xiaohong Guan

School of Computing: Conference and Workshop Papers

Nowadays, millions of Internet users watch and upload a large number of videos on User Generated Content (UGC) sites (e.g., Youtube) everyday. Moreover, online videos about hot events, such as breaking news and Olympic games, attract lots of users. In this paper, we study the characteristics of hot-event videos by collecting video traces of the largest UGC site in China for 28 days. We first empirically study statistical properties of such videos and find that hot-event videos contribute a large number of views, even though the total number of hotevent videos is relatively small. In addition, there exist extremely active …


Using Textual Features To Predict Popular Content On Digg, Paul H. Miller Apr 2011

Using Textual Features To Predict Popular Content On Digg, Paul H. Miller

Department of English: Dissertations, Theses, and Student Research

Over the past few years, collaborative rating sites, such as Netflix, Digg and Stumble, have become increasingly prevalent sites for users to find trending content.  I used various data mining techniques to study Digg, a social news site, to examine the influence of content on popularity.  What influence does content have on popularity, and what influence does content have on users’ decisions?  Overwhelmingly, prior studies have consistently shown that predicting popularity based on content is difficult and maybe even inherently impossible.  The same submission can have multiple outcomes and content neither determines popularity, nor individual user decisions.  My results show …


Optimized Delay-Sensitive Multimedia Communications Over Wireless Networks, Haiyan Luo Apr 2011

Optimized Delay-Sensitive Multimedia Communications Over Wireless Networks, Haiyan Luo

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

Multimedia communication is expected to be the major application of the next-generation wireless networks. However, providing delay-sensitive, loss-tolerant and resource-guzzling multimedia services over the current resource-limited wireless networks is still a very challenging task. In addition to their heterogeneous nature and resource limitation, wireless networks also suffer from channel variations and environmental changes. In this dissertation, we study the optimization techniques for wireless multimedia communications and address the issues from different theoretical and practical perspectives.

To solve the issues resulting from the increasingly heterogeneous wireless networks, we propose a framework for error resilient source coding and distributed application-layer error control, …


Multi-Channel Peer-To-Peer Streaming Systems As Resource Allocation Problems, Miao Wang Apr 2011

Multi-Channel Peer-To-Peer Streaming Systems As Resource Allocation Problems, Miao Wang

School of Computing: Dissertations, Theses, and Student Research

In the past few years, the Internet has witnessed the success of Peer-to-Peer (P2P) streaming technology, which has attracted millions of users. More recently, commercial P2P streaming systems have begun to support multiple channels and a user in such systems is allowed to watch more than one channel at a time. We refer to such systems as multi-channel P2P streaming systems. In this dissertation, we focus on designing multi-channel P2P streaming systems with the goal of providing optimal streaming quality for all channels, termed as system-wide optimal streaming quality. Specifically, we design the systems from the perspective of how to …


Offline Optimization Of Advance Reservation Of Bandwidth Over Dynamic Circuit Networks, Pragatheeswaran Angu Apr 2011

Offline Optimization Of Advance Reservation Of Bandwidth Over Dynamic Circuit Networks, Pragatheeswaran Angu

School of Computing: Dissertations, Theses, and Student Research

E-science projects require very high-speed and reliable networks to transfer data across various destinations in the world. Dynamic Circuit Network (DCN) is a networking service to make advance reservation of bandwidth between a source and a destination in a network. In this thesis we solve the problem of advance reservation of bandwidth in next-generation wavelength-division multiplexing (WDM) networks using a simulation based approach.
We implement a greedy algorithm and a genetic algorithm in parallel, in separate threads. The request for advance reservation is processed by both but the user gets the response only from the greedy algorithm. The genetic algorithm …


Polygonal Spatial Clustering, Deepti Joshi Apr 2011

Polygonal Spatial Clustering, Deepti Joshi

School of Computing: Dissertations, Theses, and Student Research

Clustering, the process of grouping together similar objects, is a fundamental task in data mining to help perform knowledge discovery in large datasets.  With the growing number of sensor networks, geospatial satellites, global positioning devices, and human networks tremendous amounts of spatio-temporal data that measure the state of the planet Earth are being collected every day.  This large amount of spatio-temporal data has increased the need for efficient spatial data mining techniques.  Furthermore, most of the anthropogenic objects in space are represented using polygons, for example – counties, census tracts, and watersheds.  Therefore, it is important to develop data mining …


Propeller: A Scalable Metadata Organization For A Versatile Searchable File System, Lei Xu, Hong Jiang, Xue Liu, Lei Tian, Yu Hua, Jian Hu Mar 2011

Propeller: A Scalable Metadata Organization For A Versatile Searchable File System, Lei Xu, Hong Jiang, Xue Liu, Lei Tian, Yu Hua, Jian Hu

School of Computing: Technical Reports

The exponentially increasing amount of data in file systems has made it increasingly important for users, administrators and applications to be able to fast retrieve files using file-search services, instead of replying on the standard file system API to traverse the hierarchical namespaces.  The quality of the file-search services  is significantly affected by the file-indexing overhead, the file-search performance and the accuracy of search results.  Unfortunately, the existing file-search solutions either are so poorly scalable that their performance degrades unacceptably when the systems scale up, or incur so much crawling delays that they produce acceptably inaccurate results.  We believe that …


Quantifying Performance In Fading Channels Using The Sampling Property Of A Delta Function, Won Mee Jang Mar 2011

Quantifying Performance In Fading Channels Using The Sampling Property Of A Delta Function, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We apply the sampling property of a delta function to obtain the probability of error in fading channels. Our approach reduces the integration to a sampling. The sampling point is obtained in terms of fading parameters and the average signal-to-noise ratio (SNR) to provide the closed form solution of the performance.


Identifying Horizontal Gene Transfer Using Anomalies In Protein Structures And Sequences, Venkat Ram B. Santosh Feb 2011

Identifying Horizontal Gene Transfer Using Anomalies In Protein Structures And Sequences, Venkat Ram B. Santosh

School of Computing: Dissertations, Theses, and Student Research

Genetics has traditionally focused on vertical gene transfer, which is the passing of the genetic material of an organism to its offspring. However, recent studies in genetics increased the awareness that horizontal gene transfer, which is the passing of the genetic material of an organism to another organism that is not its offspring, is also a significant phenomenon. Horizontal gene transfer is thought to play a major role in the natural evolution of bacteria, such as, when several different types of bacteria all suddenly develop the same drug resistance genes. Artificial horizontal gene transfer occurs in genetic engineering.

This thesis …


A Simple Upper Bound Of The Gaussian �-Function With Closed-Form Error Bound, Won Mee Jang Feb 2011

A Simple Upper Bound Of The Gaussian �-Function With Closed-Form Error Bound, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

We present a simple upper bound of the Gaussian Q-function with its closed-form error bound. The proposed approximation can be applied to the evaluation of the average error probability of digital modulations with its error bound. Our bit error rate (BER) bound can be easily applied to fading channels.


Nano-Particle/Quantum Dot Based Optical Dode, Dennis R. Alexander, John C. Bruce, Craig A. Zuhlke, Brandon E. Koch, Jitender S. Deogun, Haitham S. Hamza Jan 2011

Nano-Particle/Quantum Dot Based Optical Dode, Dennis R. Alexander, John C. Bruce, Craig A. Zuhlke, Brandon E. Koch, Jitender S. Deogun, Haitham S. Hamza

Department of Electrical and Computer Engineering: Faculty Publications

A particle based optical diode having at least two cavities or at least two regions of a single cavity, wherein the regions contain different types of particles.


A Midsummer Night’S Dream (With Flying Robots), Robin Murphy, Dylan Shell, Amy Guerin, Brittany Duncan, Benjamin Fine, Kevin Pratt, Takis Zourntos Jan 2011

A Midsummer Night’S Dream (With Flying Robots), Robin Murphy, Dylan Shell, Amy Guerin, Brittany Duncan, Benjamin Fine, Kevin Pratt, Takis Zourntos

School of Computing: Faculty Publications

Seven flying robot “fairies” joined human actors in the Texas A&M production of William Shakespeare’s A Midsummer Night’s Dream. The production was a collaboration between the departments of Computer Science and Engineering, Electrical and Computer Engineering, and Theater Arts. The collaboration was motivated by two assertions. First, that the performing arts have principles for creating believable agents that will transfer to robots. Second, the theater is a natural testbed for evaluating the response of untrained human groups (both actors and the audience) to robots interacting with humans in shared spaces, i.e., were believable agents created? The production used two types …


Performance Analysis Of Mimo-Sess With Alamouti Scheme Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Yaoqing Lamar Yang, Won Mee Jang Jan 2011

Performance Analysis Of Mimo-Sess With Alamouti Scheme Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Yaoqing Lamar Yang, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading sequence from the random input data stream rather than through the use of the traditional pseudo-noise code generator. It has been incorporated with multiple-input multiple-output (MIMO) systems as a means to combat fading in wireless channels. In this paper, we present the analytical study of the bit-error rate (BER) performance of MIMO-SESS systems under Rayleigh fading. The BER expressions are derived in closed form, and the veracity of the analysis is confirmed by numerical calculations that demonstrate excellent agreement with simulation results. The performance analysis shows that …


All-Dielectric Invisibility Cloaks Made Of Batio3-Loaded Polyurethane Foam, Di Bao, Khalid Z. Rajab, Yang Hao, Efthymios Kallos, Wenxuan Tang, Christos Argyropoulos, Yongzhe Piao, Shoufeng Yang Jan 2011

All-Dielectric Invisibility Cloaks Made Of Batio3-Loaded Polyurethane Foam, Di Bao, Khalid Z. Rajab, Yang Hao, Efthymios Kallos, Wenxuan Tang, Christos Argyropoulos, Yongzhe Piao, Shoufeng Yang

Department of Electrical and Computer Engineering: Faculty Publications

Transformation optics has led the way in the development of electromagnetic invisibility cloaks from science fiction to engineering practice. Invisibility cloaks have been demonstrated over a wide range of the electromagnetic spectrum, and with a variety of different fabrication techniques. However, all previous schemes have relied on the use of metamaterials consisting of arrays of sub-wavelength inclusions. We report on the first cloaking structure made of a high-k dielectric-loaded foam mixture. A polyurethane foam mixed with different ratios of barium titanate is used to produce the required range of permittivities, and the invisibility cloak is demonstrated to work for all …


Battery Capacity Footprinting And Optimization Analysis For Wireless Multimedia Communication, Jianxin Sun, Dalei Wu, Song Ci Jan 2011

Battery Capacity Footprinting And Optimization Analysis For Wireless Multimedia Communication, Jianxin Sun, Dalei Wu, Song Ci

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Micro-electronic industry has been boosting the capability of wireless mobile devices on full-scale. However, battery, as the only power source of most mobile devices, is experiencing a relatively slow development. Therefore, how to optimally utilize the limited battery energy on mobile devices under a predefined performance requirement becomes a critical issue. On the other hand, it is still unclear that how the battery capacity consumption is allocated on different working pattern of a specific video codec under various tempo-spatial scales and parameters, which has posed a design challenge on power management on multimedia communication system. Furthermore, an optimization method is …


Distributed Mimo Technologies In Cooperative Wireless Networks, Shichuan Ma, Yaoqing (Lamar) Yang, Hamid Sharif Jan 2011

Distributed Mimo Technologies In Cooperative Wireless Networks, Shichuan Ma, Yaoqing (Lamar) Yang, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Multiple-input multiple-output techniques enhance wireless communications performance by taking advantage of spatial diversity. However, most traditional MIMO systems hardly achieve large spatial diversity because of limited terminal size. In this article, we present recent advances of the distributed MIMO technologies in cooperative wireless networks. We also compare and discuss various relay protocols and cooperative strategies. Our simulation results indicate that distributed MIMO systems can provide larger spatial diversity, and the data rate in cooperative networks can be significantly increased.