Engineering Commons^™

Cylindrical Quasi-Cavity Waveguide For Static Wide Angle Pattern Projection, Kaveh Sahba, Kamal Alameh, Clifton Smith, Arie Paap

Research outputs pre 2011

Beam deflection methods such as rotary mirrors and motorized turning optical heads suffer from a variety of electro-mechanical related problems which affect laser scanning performance. These include wobble, jitter, wear, windage and synchronization issues. A novel optical structure consisting of two concentric and cylindrical interfaces with unique optical coating properties for the static projection of a laser spot array over a wide angle is demonstrated. The resulting ray trajectory through the waveguide is modeled using linear equations. Spot size growth is modeled using previously defined ray transfer matrices for tilted optical elements. The model is validated by comparison with experimental …

Fibre Bragg Grating Sensors For Acoustic Emission And Transmission Detection Applied To Robotic Nde In Structural Health Monitoring, Graham Wild, Steven Hinckley

Research outputs pre 2011

Distributed acoustic emission sensors are used in structural health monitoring (SHM) for the detection of impacts and/or strain, in real time. Secondary damage may result from the initial impact or strain. This damage may include surface pitting, erosion, or cracking. This type of damage may not be detectable by the SHM system, specifically in passive fiber optic based sensing systems. The integration of non-destructive evaluation (NDE) by robots into SHM enables the detection and monitoring of a wider variety of damage. Communicating via acoustic transmissions represents a wireless communications method for use by NDE inspection robots to communicate with an …

Adaptive Segregation-Based Mac Protocol For Real-Time Multimedia Traffic In Wlans, Hushairi Zen, Daryoush Habibi, Alexander Rassau, Justin Wyatt

Research outputs pre 2011

Wireless local area networks (WLANs) have become very popular both in private and public sectors. Despite the fast expansion of WLANs in various environments, quality of service (QoS) issues for multimedia applications in WLANs are not yet resolved. Multimedia applications contain traffic that are sensitive to delay and jitter and therefore a best-effort protocol such as the legacy IEEE 802.11 is not suitable. The 802.11e protocol provides prioritization and classification of traffic to offer better QoS for real-time services. However, it leaves the design and implementation of many important optimization features to vendors. In this paper we introduce a mechanism …

Providing Qos For Symmetrical Voice/Video Traffic In Wireless Networks, Justin Wyatt, Daryoush Habibi, Iftekhar Ahmad, Hushairi Zen

Research outputs pre 2011

Voice over IP (VoIP) and voice-video over IP (VIoIP) are becoming very popular and widespread. These types of real-time services produce streams that are almost symmetrical in nature. A new token passing media access control (MAC) developed by our group, called wireless token network (WTN), has been designed with QoS guarantees in mind. We have previously shown in our previous paper (2006) that WTN supports a higher number of VoIP clients compared to 802.11e due to its higher channel efficiency. In this paper we show that WTN also provides superior QoS for bidirectional streams such as VIoIP due to a …

Opto-Vlsi-Based Reconfigurable Free Space Optical Interconnects Architecture, Muhsen Aljada, Kamal Alameh, Yong Lee, I-S Chung

Research outputs pre 2011

This paper presents a short-distance reconfigurable high-speed optical interconnects architecture employing a Vertical Cavity Surface Emitting Laser (VCSEL) array, Opto-very-large-scale-integrated (Opto-VLSI) processors, and a photodetector (PD) array. The core component of the architecture is the Opto-VLSI processor which can be driven by digital phase steering and multicasting holograms that reconfigure the optical interconnects between the input and output ports. The optical interconnects architecture is experimentally demonstrated at 2.5 Gbps using high-speed 1×3 VCSEL array and 1×3 photoreceiver array in conjunction with two 1×4096 pixel Opto-VLSI processors. The minimisation of the crosstalk between the output ports is achieved by appropriately aligning …

Rerouting Technique For Faster Restoration Of Preempted Calls, Iftekhar Ahmad, Joarder Kamruzzaman, Daryoush Habibi

Research outputs pre 2011

In a communication network where resources are shared between instantaneous request (IR) and book-ahead (BA) connections, activation of future BA connections causes preemption of many on-going IR connections upon resource scarcity. A solution to this problem is to reroute the preempted calls via alternative feasible paths, which often does not ensure acceptably low disruption of service. In this paper, a new rerouting strategy is proposed that uses the destination node to initiate the rerouting and thereby reduces the rerouting time, which ultimately improves the service disruption time. Simulations on a widely used network topology suggest that the proposed rerouting scheme …

Optimization Of Liquid-Crystal Spatial Light Modulator For Precise Phase Generation, Seow-Hwang Eng, Dong Mei Cai, Zhenglin Wang, Kamal Alameh, Wenhan Jiang

Research outputs pre 2011

Spatial light modulators (SLMs) are recently emerging as wavefront generation or reconstruction devices. In this paper, we use a liquid-crystal SLM (LC-SLM) as a wavefront generation device through the modulation of the spatial phase distribution of an incident light beam. We characterize the phase modulation performance of the LC-SLM, and identified a polarization-configuration to minimize its amplitude modulation effects in order to maximize the contrast of reconstructed phase holograms. We also investigated the feasibility of determining the optical surface uniformity of the LC-SLM through computations of the interference fringes, and identified the disadvantages of this method. This new approach may …

Sampled Fiber Gratings For High-Resolution And High-Speed Photonic Signal Processing, Mingya Shen, Kamal Alameh

Research outputs pre 2011

A novel sampled grating for high-resolution, highspeed signal processing is presented. Simulation based on Sinc2 sampled and rational sampled fiber grating modeling show that a large number of sub-ps time delay steps are attainable, corresponding to a sampling frequency in excess of 1THz. Design method is described for deriving sampling functions that meet specific true-time-delay profile requirements.

Success? The Impact Of Involving Customers In E-Commerce Development, Julian Terry, Craig Standing

Research outputs pre 2011

In e-commerce, customers have become Information System users. In this environment of non-mandatory usage, remote, untrained users need to quickly feel comfortable and satisfied with a site encounter. Throughout the literature for four decades, a commonly cited factor pertaining to system success has been user participation in the systems development process. Among other things this is likely to lead to increased user satisfaction and the perceived usefulness of the application. This study uses findings from thirty cases of recently completed e-commerce sites in which project leaders accounts of customer participation in e-commerce development activities are analysed, along with their perceptions …

Stochastic Models For Enhancing Agility Of Supply Chains, Alok K. Verma

Engineering Technology Faculty Publications

This paper deals with the application of stochastic inventory model to the three-tier supply chain and verifying the values obtained by mathematical model with discrete event simulation. We investigate three-stage serial supply chain with stochastic demand and fixed replenishment lead-time. Inventory holding costs are charged at each stage, and each stage may incur a consumer backorder penalty cost charged by primary supplier to secondary supplier. The customer-demand follows Poisson distribution. We implement Base Stock model for inventory control at both suppliers. Computer simulation is then designed in such a way that it satisfied all the assumptions for mathematical model. Simulation …

Addressing Student Retention In Engineering And Engineering Technology Through The Use Of A Multidisciplinary Freshman Course, Anthony Dean, Bonita Anthony, Linda Vahala

Engineering Technology Faculty Publications

The Engineering Fundamentals Division of the Batten College of Engineering and Technology (BCET) at Old Dominion University administers a freshman engineering course sequence, along with four engineering departments (Mechanical Engineering, Civil and Environmental Engineering, Aerospace Engineering, and Electrical and Computer Engineering) and the Department of Engineering Technology (which offers degrees in Mechanical Engineering Technology, Civil Engineering Technology and Electrical Engineering Technology). The two course sequence, Exploring Engineering and Technology I and II, involve the five departments in teaching at least one five week module in each of the two courses. Each department generally involves the students in a basic design …

Introducing Freshmen To Construction Estimating And Scheduling Using K'Nex Bridge Kits, Carol Considine, Vernon Lewis

Engineering Technology Faculty Publications

The College of Engineering and Technology at Old Dominion University has developed project-based courses for freshmen engineering students in order to engage them in engineering early with the goal of increasing retention. The courses are divided into three five-week modules that are distributed among the various departments within the college. The Engineering Technology department is responsible for two of the five week modules. One module is comprised of all the engineering technology curriculums; civil, electrical and mechanical, and the other module is strictly a civil engineering technology project.

The civil engineering technology project is focused on the construction industry. Students …

Managing A Distance-Learning Eet Laboratory Course Using Collaboration Software, Steve Hsiung, John Hackworth, Richard Jones, June Ritchie

Engineering Technology Faculty Publications

Methods of managing various distance learning EET laboratory courses using collaboration software are detailed. Particular emphasis is given to different types of collaboration software, advantages and disadvantages of each, and student and faculty feedback on the effectiveness of each.

Identifying University Minors To Support The Construction Specialization Area Within A Civil Engineering Technology Program, Vernon Lewis, Carol Considine

Engineering Technology Faculty Publications

Construction programs at many universities are diversified and provide students with opportunities to examine topic areas that include mechanical and electrical systems, safety, business administration, residential construction, real estate, and management. It is impossible for small civil engineering technology programs with a construction emphasis to encompass all of these expertise areas. As industry looks for students with a knowledge base in these areas, it is incumbent upon programs to find avenues to provide these educational opportunities to their students.

To meet the upper division general education requirements for Old Dominion University, students must have either a minor, second major or …

Multi-Phase Flow Analysis In Oil And Gas Engineering Systems And Its Modelling, Orlando F. Ayala, Luis F. Ayala, Orlando M. Ayala

Engineering Technology Faculty Publications

[Introduction] Two-phase flow is very common in industrial processes and its applications were already in use in ages as remote as the era of Archimedes. At the present time, many industrial processes rely on multi-phase phenomena for the transport of energy and mass or for material processing. During the last century, the nuclear, chemical and petroleum industries propelled intense research activity in the area. Their efforts have been aimed at the demystification of the mechanisms taking place during this complex flow situation.

Using Building Energy Simulation And Geospatial Modeling Techniques In Determine High Resolution Building Sector Energy Consumption Profiles, Shem C. Heiple

Dissertations and Theses

A technique is presented for estimating hourly and seasonal energy consumption profiles in the building sector at spatial scales down to the individual taxlot or parcel. The method combines annual building energy simulations for cityspecific prototypical buildings and commonly available geospatial data in a Geographical Information System (GIS) framework. Hourly results can be extracted for any day and exported as a raster output at spatial scales as fine as an individual parcel (

Using Computational Fluid Dynamics Modeling To Improve The Performance Of A Solar Co2 Converter, Thomas H. Fletcher, Ralph J. Price, Reed J. Jensen

Faculty Publications

A solar collector to convert CO2 to CO at high temperature was previously developed, achieving a product with 4-6 mol % CO from pure CO2. Modeling results showed that reactions occurred in the thermal boundary layer of the heated zirconia rod at temperatures greater than 2300 K. This paper describes results of computer modeling of advanced designs meant to increase the conversion of CO from CO2. Several design modifications were tested using the model, including changing the cool-down region configuration, increasing the zirconia rod diameter, and changing the zirconia rod shape. Several operational adjustments were also modeled, including reducing the …

Aeronautical Telemetry Using Multiple-Antenna Transmitters, Michael A. Jensen, Michael D. Rice, Adam L. Anderson

Faculty Publications

The placement of multiple antennas on an air vehicle is one possible practice for overcoming signal obstruction created by vehicle maneuvering during air-to-ground transmission. Unfortunately, for vehicle attitudes where more than one of these antennas has a clear path to the receiving station, this practice also leads to self-interference nulls, resulting in dramatic degradation in the average signal integrity. This paper discusses application of unitary space-time codes such as the Alamouti transmit diversity scheme and unitary differential space-time codes to overcome the self-interference effect observed in such systems. The mathematical foundations of these techniques within the context of this application …

Machining Process Changes As A Function Of Surface Roughness, Specific To Machining Cylindrical Bores, Thomas Patrick Olsen

Dissertations and Theses @ UNI

Manufacturing professionals are challenged everyday to produce products to higher quality standards in a way that is economical and efficient. Manufacturing needs to minimize non value added costs such as reducing inventory, (non machined and finished goods), reduce work in process, and most of all eliminate waste. To exist, customers must be satisfied at the time of purchase and throughout the products lifecycle. To be competitive and remain a world class manufacture, companies must be flexible and be willing to change. Single point flexible manufacturing versus fixed spindle rigid machining greatly improves the ability to make changes. If a process …

Obstacle And Terrain Avoidance For Miniature Aerial Vehicles, Timothy Mclain, Jeff Saunders, Blake Barber, Randall W. Beard, Stephen R. Griffiths

Faculty Publications

Unmanned aerial vehicles (UAVs) are playing increasingly prominent roles in defense programs and strategy around the world. Technology advancements have enabled the development of large UAVs (e.g., Global Hawk, Predator) and the creation of smaller, increasingly capable UAVs. The focus of this Chapter is on smaller fixed-wing miniature aerial vehicles (MAVs), which range in size from % to 2 m in wingspan. As recent conflicts have demonstrated, there are numerous military applications for MAVs including reconnaissance, surveillance, battle damage assessment, and communications relays.

Heat And Mass Transport In Heat Pipe Wick Structures, Brian D. Iverson, Tyler W. Davis, Suresh V. Garimella, Mark T. North, Sukhvinder S. Kang

Faculty Publications

A novel experimental approach is developed for characterizing the performance of heat pipe wick structures. This approach simulates the actual operation of wick structures in a heat pipe. Open, partially submerged, sintered copper wicks of varying pore size are studied under the partially saturated conditions found in normal heat pipe operation. A vertical wick orientation, where the capillary lift is in opposition to gravity, is selected to test the wicks under the most demanding conditions. Mass transport measurements of the working fluid, in addition to the temperature field, are obtained for the porous wicks under the action of a discrete …