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Full-Text Articles in Computer Engineering

Sequence Design Via Semidefinite Programming Relaxation And Randomized Projection, Dian Mo Jan 2019

Sequence Design Via Semidefinite Programming Relaxation And Randomized Projection, Dian Mo

Doctoral Dissertations

Wideband is a booming technology in the field of wireless communications. The receivers in wideband communication systems are expected to cover a very wide spectrum and adaptively extract the parts of interest. The literature has focused on mixing the input spectrum to baseband using a pseudorandom sequence modulation and recovering the received signals from linearly independent measurements by parallel branches to mitigate the pressures from required extreme high sampling frequency. However, a pseudorandom sequence provides no rejection for the strong interferers received together with weak signals from distant sources. The interferers cause significant distortion due to the nonlinearity of the ...


The Analysis And Deployment Of A Fully Open Monitoring System In The Sri Lankan Deduroya Basin: The 4onse Project, Massimiliano Cannata, Daniele Strigaro, Imran Shahid, Rangajeewa Ratnayake, B.H. Sudantha Jul 2018

The Analysis And Deployment Of A Fully Open Monitoring System In The Sri Lankan Deduroya Basin: The 4onse Project, Massimiliano Cannata, Daniele Strigaro, Imran Shahid, Rangajeewa Ratnayake, B.H. Sudantha

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

The 4onse project studies non-conventional monitoring systems fully based on open technologies (hardware, standard protocols, software and data) for the management of resources and natural hazards in developing countries. After the design of hydro-meteorological stations and software for the collection, management and distribution of data, the study involves the installation of 30 stations in the Deduroya Oya river basin in Sri Lanka. The system will be analysed to fully understand the real cost of ownership, data quality and applicability in real situations. If properly validated, these systems can provide an alternative solution, effective and sustainable for the protection of property ...


Inference In Networking Systems With Designed Measurements, Chang Liu Jan 2017

Inference In Networking Systems With Designed Measurements, Chang Liu

Doctoral Dissertations

Networking systems consist of network infrastructures and the end-hosts have been essential in supporting our daily communication, delivering huge amount of content and large number of services, and providing large scale distributed computing. To monitor and optimize the performance of such networking systems, or to provide flexible functionalities for the applications running on top of them, it is important to know the internal metrics of the networking systems such as link loss rates or path delays. The internal metrics are often not directly available due to the scale and complexity of the networking systems. This motivates the techniques of inference ...


User Interface Design And Forensic Analysis For Diorama, Decision Support System For Mass Casualty Incidents, Jun Yi Jan 2015

User Interface Design And Forensic Analysis For Diorama, Decision Support System For Mass Casualty Incidents, Jun Yi

Masters Theses

In this thesis we introduces the user interface design and forensic analysis tool for DIORAMA system. With an Android device, DIORAMA provides emergency personnel the ability to collect information in real time, track the resources and manage them. It allows the responders and commanders to mange multiple incidents simultaneously. This thesis also describes the implementations of commander app and responder app, as well as two different communication strategies used in DIORAMA. Several trials and simulated mass casualty incidents were conducted to test the functionalities and performance of DIORAMA system. All responders that participated in all trials were very satisfied with ...


Evaluation Of Two-Dimensional Codes For Digital Information Security In Physical Documents, Shuai Chen Jan 2015

Evaluation Of Two-Dimensional Codes For Digital Information Security In Physical Documents, Shuai Chen

Masters Theses

Nowadays, paper documents are still frequently used and exchanged in our daily life. To safely manage confidential paper information such as medical and financial records has increasingly become a challenge. If a patient's medical diagnosis get stolen or dumped without shredding, his or her private information would be leaked. Some companies and organizations do not pay enough attention to the problem, letting their customers suffer the loss. In the thesis, I designed a hybrid system to solve this problem effectively and economically. This hybrid system integrates physical document properties with digital security technology, which brings in a revolutionary idea ...


Design And Implementation Of A High Performance Network Processor With Dynamic Workload Management, Padmaja Duggisetty Jan 2015

Design And Implementation Of A High Performance Network Processor With Dynamic Workload Management, Padmaja Duggisetty

Masters Theses

Internet plays a crucial part in today's world. Be it personal communication, business transactions or social networking, internet is used everywhere and hence the speed of the communication infrastructure plays an important role. As the number of users increase the network usage increases i.e., the network data rates ramped up from a few Mb/s to Gb/s in less than a decade. Hence the network infrastructure needed a major upgrade to be able to support such high data rates. Technological advancements have enabled the communication links like optical fibres to support these high bandwidths, but the processing ...


Energy-Efficient Content Delivery Networks, Vimal Mathew Jan 2015

Energy-Efficient Content Delivery Networks, Vimal Mathew

Doctoral Dissertations

Internet-scale distributed systems such as content delivery networks (CDNs) operate hundreds of thousands of servers deployed in thousands of data center locations around the globe. Since the energy costs of operating such a large IT infrastructure are a significant fraction of the total operating costs, we argue for redesigning them to incorporate energy optimization as a first-order principle. We focus on CDNs and demonstrate techniques to save energy while meeting client-perceived service level agreements (SLAs) and minimizing impact on hardware reliability.

Servers deployed at individual data centers can be switched off at low load to save energy. We show that ...


Asymptotic Analysis Of Random Wireless Networks: Broadcasting, Secrecy, And Hybrid Networks, Cagatay Capar Sep 2014

Asymptotic Analysis Of Random Wireless Networks: Broadcasting, Secrecy, And Hybrid Networks, Cagatay Capar

Doctoral Dissertations

This thesis work is concerned with communication in large random wireless ad hoc networks. We mathematically model the wireless network as a collection of randomly located nodes, and explore how its performance scales as the network size increases. In particular, we study three important properties: broadcasting ability, rate of information exchange, and secret communication capability. In addition, we study connectivity properties of large random graphs in a more general context, where the graph does not necessarily represent a wireless communication network.

Broadcasting, i.e., delivering a message from a single node to the entire network in a wireless ad hoc ...


Interpreting, Stephanie Jo Kent May 2014

Interpreting, Stephanie Jo Kent

Doctoral Dissertations

What do community interpreting for the Deaf in western societies, conference interpreting for the European Parliament, and language brokering in international management have in common? Academic research and professional training have historically emphasized the linguistic and cognitive challenges of interpreting, neglecting or ignoring the social aspects that structure communication. All forms of interpreting are inherently social; they involve relationships among at least three people and two languages. The contexts explored here, American Sign Language/English interpreting and spoken language interpreting within the European Parliament, show that simultaneous interpreting involves attitudes, norms and values about intercultural communication that overemphasize information and ...


Techniques For Detection Of Malicious Packet Drops In Networks, Vikram R. Desai Jan 2012

Techniques For Detection Of Malicious Packet Drops In Networks, Vikram R. Desai

Masters Theses 1911 - February 2014

The introduction of programmability and dynamic protocol deployment in routers, there would be an increase in the potential vulnerabilities and attacks . The next- generation Internet promises to provide a fundamental shift in the underlying architecture to support dynamic deployment of network protocols. In this thesis, we consider the problem of detecting malicious packet drops in routers. Specifically, we focus on an attack scenario, where a router selectively drops packets destined for another node. Detecting such an attack is challenging since it requires differentiating malicious packet drops from congestion-based packet losses. We propose a controller- based malicious packet detection technique that ...


A Study Of The Impact Of Computational Delays In Missile Interception Systems, Ye Xu Jan 2012

A Study Of The Impact Of Computational Delays In Missile Interception Systems, Ye Xu

Masters Theses 1911 - February 2014

Most publications discussing missile interception systems assume a zero computer response time. This thesis studies the impact of computer response time on single-missile single-target and multiple- missile multiple-target systems. Simulation results for the final miss distance as the computer response time increases are presented. A simple online cooperative adjustment model for multiple-missile multiple-target system is created for the purpose of studying the computer delay effect.


Leveraging Multi-Radio Communication For Mobile Wireless Sensor Networks, Jeremy J. Gummeson Jan 2011

Leveraging Multi-Radio Communication For Mobile Wireless Sensor Networks, Jeremy J. Gummeson

Masters Theses 1911 - February 2014

An important challenge in mobile sensor networks is to enable energy-efficient communication over a diversity of distances while being robust to wireless effects caused by node mobility. In this thesis, we argue that the pairing of two complementary radios with heterogeneous range characteristics enables greater range and interference diversity at lower energy cost than a single radio. We make three contributions towards the design of such multi-radio mobile sensor systems. First, we present the design of a novel reinforcement learning-based link layer algorithm that continually learns channel characteristics and dynamically decides when to switch between radios. Second, we describe a ...


Addressing/Exploiting Transceiver Imperfections In Wireless Communication Systems, Lihao Wang Jan 2011

Addressing/Exploiting Transceiver Imperfections In Wireless Communication Systems, Lihao Wang

Masters Theses 1911 - February 2014

This thesis consists of two research projects on wireless communication systems. In the first project, we propose a fast inphase and quadrature (I/Q) imbalance compensation technique for the analog quadrature modulators in direct conversion transmitters. The method needs no training sequence, no extra background data gathering process and no prior perfect knowledge of the envelope detector characteristics. In contrast to previous approaches, it uses points from both the linear and predictable nonlinear regions of the envelope detector to hasten convergence. We provide a least mean square (LMS) version and demonstrate that the quadrature modulator compensator converges.

In the second ...


Simulating A Universal Geocast Scheme For Vehicular Ad Hoc Networks, Benjamin L. Bovee Jan 2011

Simulating A Universal Geocast Scheme For Vehicular Ad Hoc Networks, Benjamin L. Bovee

Masters Theses 1911 - February 2014

Recently a number of communications schemes have been proposed for Vehicular Ad hoc Networks (VANETs). One of these, the Universal Geocast Scheme (UGS) proposed by Hossein Pishro-Nik and Mohammad Nekoui, provides for a diverse variety of VANET-specific characteristics such as time-varying topology, protocol variation based on road congestion, and support for non line-of-sight communication. In this research, the UGS protocol is extended to consider inter-vehicle multi-hop connections in intersections with surrounding obstructions along with single-hop communications in an open road scenario. Since UGS is a probabilistic, repetition-based scheme, it supports the capacity-delay tradeoffs crucial for periodic safety message exchange. The ...


Hardware Implementation Of Queue Length Based Pacing On Netfpga, Abhishek Dwaraki Jan 2011

Hardware Implementation Of Queue Length Based Pacing On Netfpga, Abhishek Dwaraki

Masters Theses 1911 - February 2014

Optical packet switching networks are the foundation for next generation high speed Internet and are fast becoming the norm rather than an option. When such high speed optical networks are taken into account, one of the key considerations is packet buffering. The importance of packet buffering plays an even bigger role in optical networks because of the physical and technological constraints on the buffer sizes that can be implemented. Existing protocols, in many real world scenarios do not perform well in such networks. To eliminate such scenarios where there is a high possibility of packet loss, we use packet pacing ...


Web-Dinar: Web Based Diagnosis Of Network And Application Resources In Disaster Response Systems, Kartik Deshpande Jan 2010

Web-Dinar: Web Based Diagnosis Of Network And Application Resources In Disaster Response Systems, Kartik Deshpande

Masters Theses 1911 - February 2014

Disaster management and emergency response mechanisms are coming of age post 9/11. Paper based triaging and evacuation is slowly being replaced with much advanced mechanisms using remote clients (Laptops, Thin clients, PDAs), RFiDs etc. This reflects a modern trend to deploy Information Technology (IT) in disaster management. IT elements provide a great a deal of flexibility and seamlessness in the communication of information. The information flowing is so critical that, loss of data is not at all acceptable. Loss of data would mean loss of critical medical information portraying the disaster scenario. This would amount to a wrong picture ...


Implementation Of Data Path Credentials For High-Performance Capabilities-Based Networks, Kamlesh T. Vasudevan Jan 2009

Implementation Of Data Path Credentials For High-Performance Capabilities-Based Networks, Kamlesh T. Vasudevan

Masters Theses 1911 - February 2014

Capabilities-based networks present a fundamental shift in the security design of network architectures. Instead of permitting the transmission of packets from any source to any destination, routers deny forwarding by default. For a successful transmission, packets need to positively identify themselves and their permissions to the router. A major challenge for a high performance implementation of such a network is an efficient design of the credentials that are carried in the packet and the verification procedure on the router. A network protocol that implements data path credentials based on Bloom filters is presented in this thesis. Our prototype implementation shows ...