Digital Communications and Networking Commons^™

Implementation Requirements For The Notice Architecture In Vehicular Communications, Dusadee Treeumnuk

Electrical & Computer Engineering Theses & Dissertations

Many studies have been focusing on Vehicular Ad-Hoc Networking (VANET) in order to increase the quality of traffic and life on the road. An important aspect in vehicular communications is maintaining the privacy and security of VANET. NOTICE is an emerging architecture promising efficient traffic notification as well as strong immunity to malicious attacks, leading to improvement of safety and reduction of traffic congestion on roadways. To enable secure traffic notification, the NOTICE system employs vehicle-to-infrastructure (V2I) communication rather than vehicle-to-vehicle (V2V) communication like in traditional VANET. The infrastructure consists of sensor belts which are embedded in the roadway and …

Decisive Routing And Admission Control According To Quality Of Service Constraints, Cindy C. Reese

Theses and Dissertations

This research effort examines, models, and proposes options to enhance command and control for decision makers when applied to the communications network. My goal is to research the viability of combining three students’ past research efforts and expanding and enhancing those efforts. The area of this research is predicting a snapshot of the communications network, context-aware routing between network nodes, and Quality of Service-based routing optimization in order to create an intelligent routing protocol platform. It will consolidate efforts from an Intelligent Agent Based Framework to Maximize Information Utility by Captain John Pecarina, Dialable Cryptography for Wireless Networks by Major …

Using A Multiobjective Approach To Balance Mission And Network Goals Within A Delay Tolerant Network Topology, Anthony L. Larweck

Theses and Dissertations

This thesis investigates how to incorporate aspects of an Air Tasking Order (ATO), a Communications Tasking Order (CTO), and a Network Tasking Order (NTO) within a cognitive network framework. This was done in an effort to aid the commander and or network operator by providing automation for battlespace management to improve response time and potential inconsistent problem resolution. In particular, autonomous weapon systems such as unmanned aerial vehicles (UAVs) were the focus of this research This work implemented a simple cognitive process by incorporating aspects of behavior based robotic control principles to solve the multi-objective optimization problem of balancing both …

The Benefits Of A Network Tasking Order In Combat Search And Rescue Missions, Murat Gocmen

Theses and Dissertations

Networked communications play a crucial role in United States Armed Forces operations. As the military moves towards more network centric (Net-Centric) operations, it becomes increasingly important to use the network as effectively as possible with respect to the overall mission. This thesis advocates the use of a Network Tasking Order (NTO), which allows operators to reason about the network based on asset movement, capabilities, and communication requirements. These requirements are likely to be derived from the Air Tasking Order (ATO), which gives insight into the plan for physical assets in a military mission. In this research we illustrate the benefit …

Voice Traffic Over Mobile Ad Hoc Networks: A Performance Analysis Of The Optimized Link State Routing Protocol, Lady Noreen P. Santos

Theses and Dissertations

This thesis investigates the performance of the Optimized Link State Routing (OLSR) protocol on Voice over Internet Protocol (VoIP) applications in Mobile Ad hoc Networks (MANETs). Using VoIP over MANETs takes advantage of the mobility and versatility of a MANET environment and the flexibility and interoperability a digital voice format affords. Research shows that VoIP-like traffic can be routed through an ad hoc network using the Ad hoc On-demand Distance Vector routing protocol. This research determines the suitability of OLSR as a routing protocol for MANETs running VoIP applications. Representative VoIP traffic is submitted to a MANET and end-to-end delay …

Optimized Robust Adaptive Networks In Supervisory Control And Data Acquisition Systems, Luis A. Oquendo Class

Theses and Dissertations

This thesis investigates the application of a Exponential Weighted Moving Average (EWMA) to be used as a memory buffer in conjunction with Special Protection Schemes (SPS) using the Electric Power and Communication Synchronizing Simulator (EPOCHS). It is proposed that using an SPS incorporating EWMA can compensate for the network layer lack of guarantee of packet delivery and provide for the stability and integrity of the power grid under a catastrophic event. The performance of the proposed SPS is evaluated using a discrete event computer simulation developed using the NS2 network simulator and the Power System Simulator for Engineering (PSS/E) power …

Stochastic Estimation And Control Of Queues Within A Computer Network, Mingook Kim

Theses and Dissertations

Captain Nathan C. Stuckey implemented the idea of the stochastic estimation and control for network in OPNET simulator. He used extended Kalman filter to estimate packet size and packet arrival rate of network queue to regulate queue size. To validate stochastic theory, network estimator and controller is designed by OPNET model. These models validated the transient queue behavior in OPNET and work of Kalman filter by predicting the queue size and arrival rate. However, it was not enough to verify a theory by experiment. So, it needed to validate the stochastic control theory with other tools to get high validity. …

The Evaluation Of Rekeying Protocols Within The Hubenko Architecture As Applied To Wireless Sensor Networks, Cory J. Antosh

Theses and Dissertations

This thesis investigates the impact of using three different rekeying protocols–pair-wise, hierarchical, and Secure Lock within a wireless sensor network (WSN) under the Hubenko architecture. Using a Matlab computer simulation, the impact of the three rekeying protocols on the number of bits transmitted across the network and the amount of battery power consumed in WSN nodes during rekey operations is investigated. Baseline pair-wise rekeying performance can be improved by using either Secure Lock or hierarchical rekeying. The best choice depends on the size of the WSN and the size of the key used. Hierarchical rekeying is the best choice for …

Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez

Theses and Dissertations

Adaptive optics applies advanced sensing and control to improve the ability of optical systems to collect images through a turbulent atmosphere. The results of this research effort demonstrate that the combination of two recent approaches improves the performance of adaptive optics in directed energy and laser communication scenarios. The first approach is adaptive control, which offers improved performance over fixed-gain controllers in the presence of rapidly changing turbulence. The second approach incorporated into the study is a dual-mirror system. The two mirrors are a high-bandwidth, low-actuator-stroke (tweeter) mirror and a low-bandwidth, large actuator-stroke (woofer) mirror. The woofer-tweeter combination allows for …

Subjective Audio Quality Over A Secure Ieee 802.11n Draft 2.0 Wireless Local Area Network, Benjamin W. Ramsey

Theses and Dissertations

This thesis investigates the quality of audio generated by a G.711 codec and transmission over an IEEE 802.11n draft 2.0 wireless local area network (WLAN). Decline in audio quality due to additional calls or by securing the WLAN with transport mode Internet Protocol Security (IPsec) is quantified. Audio quality over an IEEE 802.11n draft 2.0 WLAN is also compared to that of IEEE 802.11b and IEEE 802.11g WLANs under the same conditions. Audio quality is evaluated by following International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation P.800, where human subjects rate audio clips recorded during various WLAN configurations. The Mean …

Minimizing Spatial And Time Reservation With Collision-Aware Dcf In Mobile Ad Hoc Networks, Lubo Song, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Carrier sensing is widely adopted in wireless communication to protect data transfers from collisions. For example, distributed coordination function (DCF) in IEEE 802.11 standard renders a node to defer its communication if it senses the medium busy. For the duration of deferment, each frame carries, in its MAC header, a 16-bit number in microseconds during which any overhearing node must defer. However, even if the carrier signal is detected, both ongoing and a new communication can be simultaneously successful depending on their relative positions in the network or equivalently, their mutual interference level. Supporting multiple concurrent communications is …

High-Performance Broadcast And Multicast Protocols For Multi-Radio Multi-Channel Wireless Mesh Networks, Jun Wang

Electrical & Computer Engineering Theses & Dissertations

Recently, wireless mesh networks (WMNs) have attracted much attention. A vast amount of unicast, multicast and broadcast protocols has been developed for WMNs or mobile ad hoc networks (MANETs). First of all, broadcast and multicast in wireless networks are fundamentally different from the way in which wired networks function due to the well-known wireless broadcast/multicast advantage. Moreover, most broadcast and multicast protocols in wireless networks assume a single-radio single-channel and single-rate network model, or a generalized physical model, which does not take into account the impact of interference. This dissertation focuses on high-performance broadcast and multicast protocols designed for multi-radio …

A Three-Dimensional Pattern-Space Representation For Volumetric Arrays, William C. Barott, Paul G. Steffes

Publications

A three-dimensional pattern-space representation is presented for volumetric arrays. In this representation, the radiation pattern of an array is formed by the evaluation of the three-dimensional pattern-space on a spherical surface. The scan angle of the array determines the position of this surface within the pattern-space. This pattern-space representation is used in conjunction with a genetic algorithm to minimize the sidelobe levels exhibited by a thinned volumetric array during scanning.

Optimisation Of Multicast Routing In Wireless Mesh Networks, Brian Keegan, Karol Kowalik, Mark Davis

Conference papers

In recent years Wireless Mesh Networks have been deployed and grown in popularity in many metropolitan areas. The deployment of such networks has allowed clients to gain access to publicly available broadband networks. The implementation of wireless mesh networks requires that backhaul services (traditionally carried by wired networks) be maintained via wireless mesh points. Because of their structure, wireless mesh networks provide an excellent means for targeting a large group of end users or simply to relay data. This may be achieved by means of broadcasting or more specifically multicasting. The lack of standards and support for multicasting over wireless …

Biomarker Identification For Prostate Cancer Using An Efficient Feature Selection Algorithm, Vamsi Krishnam Raju Mantena

Electrical & Computer Engineering Theses & Dissertations

In recent years, there has been an increased interest in using protein mass spectrometry to identify biomarkers that discriminate diseased from healthy individuals. A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathological processes, or pharmacological responses to a therapeutic intervention. Identifying biomarkers will be an important step towards disease characterization and patient management. One challenge of biomarker identification is how to handle the high dimensional mass spectral data. In this thesis, we applied an efficient feature selection algorithm to mass spectrometry data obtained from prostate tissue samples to identify prostate …

Performance Of Adaptive Wireless Systems With Feedback, Sirisha Koduri

Electrical & Computer Engineering Theses & Dissertations

Future generations of wireless systems will employ versatile transmitters and receivers based on software defined radios that are capable of adapting in response to changes in the operating environment to meet the specified quality of service requirements. In adaptive wireless systems, transmitters use feedback from the receiver to update characteristics of the transmitted signal to changing patterns of interference. In this thesis, the performance of transmitter adaptation algorithms with limited feedback and the system performance as a function in which the interference information is quantized for transmission over the feedback channel are analyzed. The results of this thesis were presented …

Congestion Mitigation In Wireless Sensor Networks Using Single-Hop Backpressure Algorithm, Vijay Shekar Mangilipalli Gangu Sham

Electrical & Computer Engineering Theses & Dissertations

Wireless sensor networks consist of a group of small components with limited resources allocated to sense the environment and transmit data to the user or interpreter. This concept is technically evolved from Sensors that are basically used to sense the environment around and collect data based on the sensing application incorporated in them. An extension to functionality of the sensors leads to the concept of sensor networks, where, in addition to gathering information at individual sensors, the data is processed and transmitted to a central station or Base station. This concept of transmitting the information from one node to the …

Resource Sharing Via Planed Relay For Hwn, Chong Shen, Susan Rea, Dirk Pesch

NIMBUS Articles

We present an improved version of adaptive distributed cross-layer routing algorithm (ADCR) for hybrid wireless network with dedicated relay stations () in this paper. A mobile terminal (MT) may borrow radio resources that are available thousands mile away via secure multihop RNs, where RNs are placed at pre-engineered locations in the network. In rural places such as mountain areas, an MT may also communicate with the core network, when intermediate MTs act as relay node with mobility. To address cross-layer network layers routing issues, the cascaded ADCR establishes routing paths across MTs, RNs, and cellular base stations (BSs) and provides …

Antennas For Portable Communications In The Uwb And Gps Spectra., Giuseppe Ruvio

Doctoral

The thesis describes a study of antennas for solutions in emerging systems. An account of the fundamental principles of these antennas is given together with an outline of the basic electromagnetic theory on which the designs are based. While the main focus is on antennas for Ultra Wideband (UWB) systems, some additional work was carried out on enhancing performance of circularly polarised antennas for satellite navigation systems. The study focussed on the design of highly efficient broadband antennas with particular requirements for size compactness, gain stability, phase-linearity, and the use of low-cost materials. These requirements are particularly important for UWB …

The Effects Of Contention Among Stations On Video Streaming Applications Over Wireless Local Area Networks: An Experimental Approach, Nicola Cranley, Tanmoy Debnath

Conference papers

Multimedia streaming applications have a large impact on the resource requirements of the WLAN. There are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management and the provision of QoS guarantees extremely difficult. For video streaming applications, packet loss and packets dropped due to excessive delay are the primary factors that affect the received video quality. In this paper, we experimentally analyse the effects of contention on the performance of video streaming applications with a given delay constraint …

Distributed Cluster-Based Outlier Detection In Wireless Sensor Networks, Swetha Gali

Electrical & Computer Engineering Theses & Dissertations

Wireless sensor networks find several potential applications in a variety of fields, such as environmental monitoring and control, battlefields, surveillance, smart buildings, human health monitoring, etc. These sensor networks consist of a large number of very tiny, inexpensive, and low power sensor nodes, which are deployed in a variety of harsh environments that may result in the sensor data getting corrupted. It is thus critical to detect and report these abnormal values in the sensor data, in order to have a better understanding of the monitored environment. Detection of the abnormal values is of special interest for the sensor network …

Performance Analysis Of Ieee 802.11b Devices In The Presence Of Interference Aware Scheduling-Adaptive Frequency Hopping Enabled Bluetooth Devices, Deepthi Gopalpet

Electrical & Computer Engineering Theses & Dissertations

Wireless Local Area networks (WLAN) and Wireless Personal Area Networks (WPAN) provide complimentary services using the same unlicensed radio frequency band of operation. The 802.11b WLAN operates in the 2.4 GHz band and uses a Direct Sequence Spread Spectrum technique. It is designed to cover large areas ranging up to 100 meters in diameter, which may connect hundreds of computers. Bluetooth (BT) WPAN also operates in the same frequency band as the IEEE 802.lib and it uses a Frequency Hopping Spread Spectrum technique. BT is primarily used for communications between notebooks, palm units and other personal computing devices within relatively …

Maximizing Communication Concurrency Via Link-Layer Packet Salvaging In Mobile Ad Hoc Networks, Chansu Yu, Kang G. Shin, Lubo Song

Electrical and Computer Engineering Faculty Publications

Carrier-sense medium access control (MAC) protocols such as the IEEE 802.11 distributed coordination function (DCF) avoid collisions by holding up pending packet transmission requests when a carrier signal is observed above a certain threshold. However, this often results in unnecessarily conservative communication, thus making it difficult to maximize the utilization of the spatial spectral resource. This paper shows that a higher aggregate throughput can be achieved by allowing more concurrent communications and adjusting the communication distance on the fly, which needs provisions for the following two areas. On the one hand, carrier sense-based MAC protocols do not allow aggressive communication …

Detecting Compromised Nodes In Wireless Sensor Networks, Mary Lisa Mathews

Electrical & Computer Engineering Theses & Dissertations

While wireless sensor networks are proving to be a versatile tool, many of the applications in which they are utilized have sensitive data. Therefore, security is crucial in many of these applications. Once a sensor node has been compromised, the security of the network degrades quickly if measures are not taken to deal with this event. There have been many approaches researched to tackle the issue. In this thesis, an anomaly-based intrusion detection protocol is developed to detect compromised nodes in wireless sensor networks.

The proposed protocol is implemented after the sensors are deployed into the environment in which they …

Fault Arrangements And Their Effect On The Performance Of Wireless Sensor Networks, Dwayne Sayone Blai

Electrical & Computer Engineering Theses & Dissertations

Wireless sensor networks face many reliability challenges. The networks are deployed in open, hostile environments, making them easily susceptible to network failure. As a result, there are countless faults that can occur in sensor networks, from component failure to outside attacks. Outside attacks take place when an adversary gains control over a node or set of nodes in the network. Outside attackers can destroy a network in numerous ways such as random attacks, clustering attacks, search-based attacks, etc. The method and strategy used in each of these attacks directly affects the network's reliability. Understanding how these adversaries are positioned is …

An Operational Model For Mobile Sensor Cloud Management, Indrajeet Kalyankar

Electrical & Computer Engineering Theses & Dissertations

Mobile sensors provide a safe, cost effective method for gathering information in hazardous environments. When the hazardous environment is either unexplored, such as the surface of Mars, or unanticipated, such as the result of chemical contamination, it is desirable for a system to gather information with a minimal amount of outside control (localization, decision control, etc.) and prepositioned sensors. If one takes a look at the number of the sensors deployed on a scale, at the lower end is the sole, multipurpose sensor unit. The upper end deals with hordes of inexpensive, expendable sensors. In the middle, a cluster of …

An Experimental Analysis Of The Call Capacity Of Ieee 802.11b Wireless Local Area Networks For Voip Telephony, Brian Keegan, Mark Davis

Conference papers

In this paper we present the results from an experimental study of the call capacity of an IEEE 802.11b network when using VoIP telephony. Experiments include increasing the number of VoIP users in a wireless test-bed and increasing the level of background traffic until network saturation occurs. The experiments allow us to perform an analysis of the access point (AP) buffer dynamics. Results show that the network is capable of supporting up to 16 VoIP stations (STAs). Due to the operation of the IEEE 802.11 medium access control (MAC) mechanism, the AP acts as a bottleneck for all traffic destined …

End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith

Electrical and Computer Engineering Faculty Publications

This paper presents an evaluation of the end-to-end latency of a fault-tolerant CORBA infrastructure that we have implemented. The fault-tolerant infrastructure replicates the server applications using active, passive and semi-active replication, and maintains strong replica consistency of the server replicas. By analyses and by measurements of the running fault-tolerant infrastructure, we characterize the end-to-end latency under fault-free conditions. The main determining factor of the run-time performance of the fault-tolerant infrastructure is the Totem group communication protocol, which contributes to the end-to-end latency primarily in …

The Reliability Of The Computer Communication Networks Including Mobile Nodes, Sahin Yasar

Electrical & Computer Engineering Theses & Dissertations

The wireless computer networks have an uncertainty in their structures aside from their big advantages for the users. The environmental conditions, changing locations of the mobile hosts and the changing components in the system can easily affect their reliability. In order to know a system capability performing its functions, keep the reliability at a certain level and/or detect the deficiency of the system, it is necessary to analyze the reliability of a computer communication network including the wired and wireless parts. But the above reasons also make the analysis and a unique solution difficult so a set of algorithms is …

Supplementing An Ad-Hoc Wireless Network Routing Protocol With Radio Frequency Identification (Rfid) Tags, Leroy S. Willemsen

Theses and Dissertations

Wireless sensor networks (WSNs) have a broad and varied range of applications, yet all of these are limited by the resources available to the sensor nodes that make up the WSN. The most significant resource is energy. A WSN may be deployed to an inhospitable or unreachable area, leaving it with a non-replenishable power source. This research examines a way of reducing energy consumption by augmenting the nodes with radio frequency identification (RFID) tags that contain routing information. It was expected that RFID tags would reduce the network throughput, the ad hoc on-demand distance vector (AODV) routing traffic sent, and …