Open Access. Powered by Scholars. Published by Universities.®

Computer Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 123

Full-Text Articles in Computer Engineering

Multiframe Coded Computation For Distributed Uplink Channel Decoding, Brinell F. Monteiro May 2019

Multiframe Coded Computation For Distributed Uplink Channel Decoding, Brinell F. Monteiro

Theses

The latest 5G technology in wireless communication has led to an increasing demand for higher data rates and low latencies. The overall latency of the system in a cloud radio access network is greatly affected by the decoding latency in the uplink channel. Various proposed solutions suggest using network function virtualization (NFV). NFV is the process of decoupling the network functions from hardware appliances. This provides the exibility to implement distributed computing and network coding to effectively reduce the decoding latency and improve the reliability of the system. To ensure the system is cost effective, commercial off the shelf (COTS ...


Design, Analysis And Optimization Of Visible Light Communications Based Indoor Access Systems For Mobile And Internet Of Things Applications, Sihua Shao May 2018

Design, Analysis And Optimization Of Visible Light Communications Based Indoor Access Systems For Mobile And Internet Of Things Applications, Sihua Shao

Dissertations

No abstract provided.


Multi-Population-Based Differential Evolution Algorithm For Optimization Problems, Ishani Chatterjee May 2017

Multi-Population-Based Differential Evolution Algorithm For Optimization Problems, Ishani Chatterjee

Theses

A differential evolution (DE) algorithm is an evolutionary algorithm for optimization problems over a continuous domain. To solve high dimensional global optimization problems, this work investigates the performance of differential evolution algorithms


Decision Tree Rule-Based Feature Selection For Imbalanced Data, Haoyue Liu May 2017

Decision Tree Rule-Based Feature Selection For Imbalanced Data, Haoyue Liu

Theses

A class imbalance problem appears in many real world applications, e.g., fault diagnosis, text categorization and fraud detection. When dealing with an imbalanced dataset, feature selection becomes an important issue. To address it, this work proposes


Source-Channel Coding For Coordination Over A Noisy Two-Node Network, Sarah A. Obead Dec 2016

Source-Channel Coding For Coordination Over A Noisy Two-Node Network, Sarah A. Obead

Theses

Recently, the concept of coordinating actions between distributed agents has emerged in the information theory literature. It was first introduced by Cuff in 2008 for the point-to-point case of coordination. However, Cuff’s work and the vast majo


Subspace Methods For Portfolio Design, Onur Yilmaz May 2016

Subspace Methods For Portfolio Design, Onur Yilmaz

Dissertations

Financial signal processing (FSP) is one of the emerging areas in the field of signal processing. It is comprised of mathematical finance and signal processing. Signal processing engineers consider speech, image, video, and price of a stock as signals of interest for the given application. The information that they will infer from raw data is different for each application. Financial engineers develop new solutions for financial problems using their knowledge base in signal processing. The goal of financial engineers is to process the harvested financial signal to get meaningful information for the purpose.

Designing investment portfolios have always been at ...


Online Algorithms For Content Caching: An Economic Perspective, Ammar Gharaibeh Jan 2016

Online Algorithms For Content Caching: An Economic Perspective, Ammar Gharaibeh

Dissertations

Content Caching at intermediate nodes, such that future requests can be served without going back to the origin of the content, is an effective way to optimize the operations of computer networks. Therefore, content caching reduces the delivery delay and improves the users’ Quality of Experience (QoE). The current literature either proposes offline algorithms that have complete knowledge of the request profile a priori, or proposes heuristics without provable performance. In this dissertation, online algorithms are presented for content caching in three different network settings: the current Internet Network, collaborative multi-cell coordinated network, and future Content Centric Networks (CCN). Due ...


System Design And Performance Analysis Of Asymmetrically And Symmetrically Clipped Optical (Asco)-Ofdm For Im/Dd Optical Wireless Communications, Nan Wu May 2015

System Design And Performance Analysis Of Asymmetrically And Symmetrically Clipped Optical (Asco)-Ofdm For Im/Dd Optical Wireless Communications, Nan Wu

Dissertations

As the quantity of mobile communication devices, such as cellphones, tablets, and laptops, dramatically increase, the demand for high speed wireless service has been growing. Optical wireless communications (OWCs), which offer unlimited transmission bandwidth, have received a lot of attention and been studied in recent decades. They can be an effective alternative to radio frequency communications (RFCs) for indoor high speed data transmission. Intensity modulation direct detection (IM/DD) is a simple way to realize the transmission of optical wireless signals in an indoor environment. Information data streams are modulated into the intensity of optical carriers and transmitted by light ...


Novel Algorithms For Fair Bandwidth Sharing On Counter Rotating Rings, Mete Yilmaz Dec 2012

Novel Algorithms For Fair Bandwidth Sharing On Counter Rotating Rings, Mete Yilmaz

Dissertations

Rings are often preferred technology for networks as ring networks can virtually create fully connected mesh networks efficiently and they are also easy to manage. However, providing fair service to all the stations on the ring is not always easy to achieve.

In order to capitalize on the advantages of ring networks, new buffer insertion techniques, such as Spatial Reuse Protocol (SRP), were introduced in early 2000s. As a result, a new standard known as IEEE 802.17 Resilient Packet Ring was defined in 2004 by the IEEE Resilient Packet Ring (RPR) Working Group. Since then two addenda have been ...


Energy-Efficient Multi-Criteria Packet Forwarding In Multi-Hop Wireless Networks, Komlan Egoh May 2012

Energy-Efficient Multi-Criteria Packet Forwarding In Multi-Hop Wireless Networks, Komlan Egoh

Dissertations

Reliable multi-hop packet forwarding is an important requirement for the implementation of realistic large-scale wireless ad-hoc networks. However, packet forwarding methods based on a single criterion, such as the traditional greedy geographic forwarding, are not sufficient in most realistic wireless settings because perfect-reception-within-rangecannot be assumed. Furthermore, methods where the selection of intermediate relaying nodes is performed at the transmitter-side do not adapt well to rapidly changing network environments. Although a few link-aware geographic forwarding schemes have been reported in the literature, the tradeoffs between multiple decision criteria and their impact on network metrics such as throughput, delay and energy ...


Vector Coprocessor Sharing Techniques For Multicores: Performance And Energy Gains, Spiridon Florin Beldianu May 2012

Vector Coprocessor Sharing Techniques For Multicores: Performance And Energy Gains, Spiridon Florin Beldianu

Dissertations

Vector Processors (VPs) created the breakthroughs needed for the emergence of computational science many years ago. All commercial computing architectures on the market today contain some form of vector or SIMD processing.

Many high-performance and embedded applications, often dealing with streams of data, cannot efficiently utilize dedicated vector processors for various reasons: limited percentage of sustained vector code due to substantial flow control; inherent small parallelism or the frequent involvement of operating system tasks; varying vector length across applications or within a single application; data dependencies within short sequences of instructions, a problem further exacerbated without loop unrolling or other ...


High-Performance Matrix Multiplication On Intel And Fgpa Platforms, Gang Li May 2012

High-Performance Matrix Multiplication On Intel And Fgpa Platforms, Gang Li

Theses

Matrix multiplication is at the core of high-performance numerical computation. Software methods of accelerating matrix multiplication fall into two categories. One is based on calculation simplification. The other one is based on increasing the memory access efficiency. Also matrix multiplication can be accelerated using vector processors. In this investigation, various matrix multiplication algorithms and the vector-based hardware acceleration method are analyzed and compared in terms of performance and memory requirements. Results are shown for Intel and Xilinx FPGA platforms. They show that when the CPU is fast, Goto's algorithm runs faster than Strassen's algorithm because the data access ...


Energy Scavenging System For Indoor Wireless Sensor Network, David Andrew Crea Dec 2010

Energy Scavenging System For Indoor Wireless Sensor Network, David Andrew Crea

Theses

As wireless communication evolves wireless sensors have begun to be integrated into society more and more. As these sensors are used to a greater extent newer and better ways to keep them working optimally have begun to surface. One such method aims to further the sensors energy independence on humans. This technique is known as energy scavenging. The logic behind energy scavenging is to allow the device to have its own reliable source of energy that does not require upkeep, has a long life expectancy, and does not completely rely on an internal power source. The aim of this thesis ...


Modeling Next Generation Air Traffic Control System With Petri Net, Hang Wu Dec 2010

Modeling Next Generation Air Traffic Control System With Petri Net, Hang Wu

Theses

The Federal Aviation Administration (FAA) is one of the largest Air Navigation Service Providers, managing air traffic for more than 15% of the world's airspace. Today's Air Traffic Control (ATC) system cannot meet the growth of the air traffic activities, which brings with more unprecedented delays. At the same time, Air Traffic Controllers are facing higher workload than ever before. The FAA has declared that the existing ATC system will transition to a new system known as “Free Flight”. “Free Flight” will change today's ATC system by giving pilots increased flexibility to choose and modify their routes ...


Hardware Support For Real-Time Network Security And Packet Classification Using Field Programmable Gate Arrays, Nitesh Bhicu Guinde May 2010

Hardware Support For Real-Time Network Security And Packet Classification Using Field Programmable Gate Arrays, Nitesh Bhicu Guinde

Dissertations

Deep packet inspection and packet classification are the most computationally expensive operations in a Network Intrusion Detection (NID) system. Deep packet inspection involves content matching where the payload of the incoming packets is matched against a set of signatures in the database. Packet classification involves inspection of the packet header fields and is basically a multi-dimensional matching problem. Any matching in software is very slow in comparison to current network speeds. Also, both of these problems need a solution which is scalable and can work at high speeds. Due to the high complexity of these matching problems, only Field-Programmable Gate ...


Soft-Error Resilient On-Chip Memory Structures, Shuai Wang Dec 2009

Soft-Error Resilient On-Chip Memory Structures, Shuai Wang

Dissertations

Soft errors induced by energetic particle strikes in on-chip memory structures, such as L1 data/instruction caches and register files, have become an increasing challenge in designing new generation reliable microprocessors. Due to their transient/random nature, soft errors cannot be captured by traditional verification and testing process due to the irrelevancy to the correctness of the logic. This dissertation is thus focusing on the reliability characterization and cost-effective reliable design of on-chip memories against soft errors.

Due to various performance, area/size, and energy constraints in various target systems, many existing unoptimized protection schemes on cache memories may eventually ...


On Modeling And Mitigating New Breed Of Dos Attacks, Amey Bhaskar Shevtekar May 2009

On Modeling And Mitigating New Breed Of Dos Attacks, Amey Bhaskar Shevtekar

Dissertations

Denial of Service (DoS) attacks pose serious threats to the Internet, exerting in tremendous impact on our daily lives that are heavily dependent on the good health of the Internet. This dissertation aims to achieve two objectives:1) to model new possibilities of the low rate DoS attacks; 2) to develop effective mitigation mechanisms to counter the threat from low rate DoS attacks.

A new stealthy DDoS attack model referred to as the "quiet" attack is proposed in this dissertation. The attack traffic consists of TCP traffic only. Widely used botnets in today's various attacks and newly introduced network ...


Two Factor Authentication And Authorization In Ubiquitous Mobile Computing, Qing Zhu Dec 2007

Two Factor Authentication And Authorization In Ubiquitous Mobile Computing, Qing Zhu

Theses

Handheld devices, such as mobile phones, PDAs and others, have become an integrated part of our lives. They are perfectly suitable to become the first real-life platforms for mobile computing applications. A lightweight holistic authentication and authorization scheme is presented for this typical wireless scenario. It is shown that either SIM or Kerberos authentication has its limitations. A two-factor authentication method SIM-based Kerberos authentication is developed to implement the Secure Single Sign-on function with LDAP protocol realization for authorization and mobile directory services. Performance analysis and power consumption analyses for this protocol are presented as well. Our results show that ...


Kerberos Phone Secure Messenger, Nabeel Al-Saber Dec 2007

Kerberos Phone Secure Messenger, Nabeel Al-Saber

Theses

Security is becoming vital in today's open insecure Internet. While popular Internet enabled mobile devices are spreading widely, the security of such platforms is not maturely addressed. This research extends the popular Kerberos authentication protocol to run on mobile phones and builds a novel Kerberos Secure Phone Messenger (KSPM) on top of the protocol. Moreover, the Kerberos network authentication protocol provides user authentication and message privacy with the convenience of secret key cryptography. Such an advantage in mobile phones helps reduce the computational burden and power consumption if compared with public key cryptography. KSPM achieves high standards in terms ...


Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee Dec 2007

Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee

Theses

The problem of designing retransmission protocols based on Hybrid Automatic Repeat reQuest (HARQ) for moving networks over Ricean fading channels has been considered. The scenario of interest consists of one receiver traveling at a given speed while connected to a wireless network based on OFDM (e.g., WiMax) through several base stations located along the path. Five different retransmission protocols that combine HARQ with handover between adjacent base stations are considered. Their performance in terms of number of retransmissions per packet via numerical simulations, considering both frequency selective and nonselective channels are presented. The results obtained show the relevant advantage ...


Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin Dec 2007

Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin

Theses

With the continuous expansion of network infrastructure and deployment of applications sensitive to Quality-of-Service, network measurement plays a major role in both network planning and management. Accurate measurement of various network parameters, e.g., available bandwidth, link capacity, delay, packet loss and jitter, provides a positive impact for effective traffic engineering, Quality-of-Service (QoS) routing, optimization of end-to-end transport performance, and link capacity planning. For network measurement, there exists several proactive estimation tools based on either probe-gap model or probe-rate model that estimate path related attributes. Most of these tools that have been implemented can measure tight-link capacity (smallest available bandwidth ...


Route Recovery Schemes For Link And Node Failure And Link Congestion, Ibrahim Takouna Aug 2007

Route Recovery Schemes For Link And Node Failure And Link Congestion, Ibrahim Takouna

Theses

Link/Node failure occurs frequently causing service disruption in computer networks. Hardware techniques have been developed to protect the network from Link/Node failure. These techniques work in physical layer, therefore their convergence time is very small. On the other hand, many schemes have been proposed to mitigate the failure influence on the network. These schemes work in upper layers such as the network layer. However, hardware solutions faster than other schemes, but they are expensive. Link/Node failure causes all flows which were using the failed link/node are temporarily interrupted till a new path reestablished.

Three recovery algorithms ...


Development And Evaluation Of A Simultaneous Multithreading Processor Simulator, Carla Verena S. Nunez May 2007

Development And Evaluation Of A Simultaneous Multithreading Processor Simulator, Carla Verena S. Nunez

Theses

Modem processors are designed to achieve greater amounts of instruction level parallelism (ILP) and thread level parallelism (TLP). Simultaneous multithreading (SMT) is an architecture that exploits both LLP and TLP. It improves the utilization of the processor resources by allowing multiple independent threads to reside in the pipeline and dynamically scheduling the available resources among the threads.

The first part of this thesis presents the development of a simultaneous multithreading processor simulator. The SMT simulator is derived from SimpleScalar, a superscalar processor simulator widely used in the computer architecture research field. The basic pipeline is expanded to allow multiple threads ...


Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang Dec 2006

Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang

Dissertations

The Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of a mobile fading channel. Accurate estimation of the mobile speed is important in wireless mobile applications which require such as knowledge of the rate of channel variations. In this dissertation, first the performance of classical crossing- and covariance-based speed estimators is studied. Next, the problem of mobile speed estimation using diversity combining is investigated. Then, a nonparametric estimation technique is proposed that is robust to different channel variations. Finally, cyclostationarity-based speed estimators which can be applied either blindly or with the aid of pilot ...


Non-Repudiation Secure File Transfer Protocol (Nrsftp), Jerry Chen Dec 2006

Non-Repudiation Secure File Transfer Protocol (Nrsftp), Jerry Chen

Theses

Non Repudiation Secure File Transfer Protocol (NRSFTP) is designed to resolve three main concerns for today's electronic file transfer methodology. The three main concerns are Non-Repudiation, Secure, and Non-Real Time file transfer. Non-repudiation is to assure the receiver that the sender of the document is not an imposter. Secure document transfer is to assure the sender that only the intended receiver will be able to read the document. Non-real-time file transfer is to provide convenient and low cost transportability of the encrypted data from one party to another. With the above three concerns addressed, the NRSFTP protocol can be ...


On Mitigating Distributed Denial Of Service Attacks, Zhiqiang Gao Aug 2006

On Mitigating Distributed Denial Of Service Attacks, Zhiqiang Gao

Dissertations

Denial of service (DoS) attacks and distributed denial of service (DDoS) attacks are probably the most ferocious threats in the Internet, resulting in tremendous economic and social implications/impacts on our daily lives that are increasingly depending on the wellbeing of the Internet. How to mitigate these attacks effectively and efficiently has become an active research area. The critical issues here include 1) IP spoofing, i.e., forged source lIP addresses are routinely employed to conceal the identities of the attack sources and deter the efforts of detection, defense, and tracing; 2) the distributed nature, that is, hundreds or thousands ...


Fpga-Based Implementation Of Parallel Graph Partitioning, Mohammad Kharashgeh Aug 2006

Fpga-Based Implementation Of Parallel Graph Partitioning, Mohammad Kharashgeh

Theses

Graph partitioning is a very important application that can be found in numerous areas, from finite element methods to data processing and VLSI circuit design. Many algorithms have been developed to solve this problem. Of special interest is multilevel graph partitioning that provides a very efficient solution. This method can also be parallelized and implemented on various multiprocessor architectures. Unfortunately, the target of such implementations is often unavailable high-end multiprocessor systems. Here a parallel version of this method for an in-house developed multiprocessor system is implemented on an FPGA. The system designed provides a cost-effective solution.

The design is based ...


A Wireless Method For Monitoring Medication Compliance, Jeffrey Scott Jonas Aug 2006

A Wireless Method For Monitoring Medication Compliance, Jeffrey Scott Jonas

Theses

There are many devices on the market to help remind patients to take their pills, but most require observation by a caregiver to assure medication compliance. This project demonstrates three modes to detect pill removal from a pillbox: a switch under the pills, a reflective type photointerrupter and a transmissive "electric eye" photosensor. Each mode exhibited blind spots or other failures to detect pill presence, but by combining modes with complementary characteristics, the accuracy of pill detection is greatly increased.

Two methods of caregiver notification are demonstrated: text messages transmitted via an attached cellular phone, or the status is collected ...


Location Estimation In A 3d Environment Using Radio Frequency Identification Tags, Adwitiya Akash Jain May 2006

Location Estimation In A 3d Environment Using Radio Frequency Identification Tags, Adwitiya Akash Jain

Theses

RFID tag location estimation in a 3D environment is investigated. The location of the tag with unknown coordinates can be estimated with certain accuracy. However, accuracy can be improved using the knowledge based on measurement of additional reference tags with known location. This thesis studies the mathematical formulation and practical realization of location sensing using RFID tags.

Deviating from the standard use of RFID technology which employs one tag reader to identify the presence of tag, here multiple tag readers with known location are used to estimate the physical location of an individual tag, with/without the help of few ...


Classification, Testing And Optimization Of Intrusion Detection Systems, Javier Leon May 2006

Classification, Testing And Optimization Of Intrusion Detection Systems, Javier Leon

Theses

Modem network security products vary greatly in their underlying technology and architecture. Since the introduction of intrusion detection decades ago, intrusion detection technologies have continued to evolve rapidly. This rapid change has led to the introduction of a wealth of security devices, technologies and algorithms that perform functions originally associated with intrusion detection systems.

This thesis offers an analysis of intrusion detection technologies, proposing a new classification system for intrusion detection systems. Working closely with the development of a new intrusion detection product, this thesis introduces a method of testing related technologies in a production environment by outlining and executing ...