James J. Sluss

Reversing the Trend of Engineering Enrollment Declines With Innovative Outreach, Recruiting, and Retention Programs

This paper discusses an all-encompassing approach to increase the number of students in engineering through innovative outreach, recruiting, and retention programs. Prior to adopting these programs, the School of Electrical and Computer Engineering (ECE) at the University of Oklahoma (OU), Norman, experienced a reduction in engineering enrollment similar to the trend that has occurred across the U.S. over the last few years. As a result, the school investigated the key factors that influence selection of engineering as a career path and initiated a corrective program to reverse this trend. The program involves focusing on the present through retention, on the immediate future through recruiting, and on the distant future through outreach. The focus of all of these programs is to mobilize the OU-ECE faculty and student body to present advanced engineering technologies, innovative demonstrations, and hands-on activities at a level that the individual student can understand and appreciate. Student surveys and interviews are used to assess the program qualitatively, and OU-ECE enrollment numbers are used as a quantitative assessment.

Free-space optical wavelength diversity scheme for fog mitigation in a ground-to-unmanned-aerial-vehicle communications link

Atmospheric weather conditions adversely affect the performance of free-space optical communications systems. Fog present in the atmosphere has the largest impact on free-space optical systems. We use simulation techniques to investigate the performance of a slant-path, wavelength-diversified free-space optical link between a ground station and an unmanned aerial vehicle in the presence of radiation fog. The free-space optical link is configured to operate using the simultaneous transmission of three wavelengths, 0.85, 1.55, and 10 µm, connecting a ground station to an unmanned aerial vehicle operating at either a 4- or 8-km altitude. The link is further analyzed by combining the multiple carrier wavelengths into either an equal-gain diversity scheme or a selective diversity scheme. The simulation results are obtained using ALTM and PcModWin simulation software from Ontar Corporation. The results obtained demonstrate that the use of either an equal-gain diversity scheme or a selective diversity scheme enables the deployment of a ground-to-air free-space optical communications link. Furthermore, a selective diversity scheme demonstrates a received power approximately three times greater than an equal-gain diversity scheme.

The transmission of multiple RF signals in free-space optics using wavelength division multiplexing

Free-space optics (FSO) is a technology that uses modulated optical lasers to transmit information in a line-of-sight path through the atmosphere. To date, the major focus of FSO research and development has been toward the transmission of digital data, mostly for “last mile” applications. This paper investigates the simultaneous transportation of multiple analog radio frequency (RF) signals over a single FSO link using wavelength division multiplexing (WDM) technology. Experimental measurements of optical peak power and signal-to-noise ratio (SNR) indicate the suitability of FSO links for supporting WDM applications.

Wavelength diversity in free-space optics to alleviate fog effects

Free-space optical communication systems are adversely affected by weather conditions, especially fog. The objective of this paper is to examine the use of wavelength diversity in free-space optics to mitigate the effect of fog on the received optical signal strength. The source information was encoded and transmitted onto three carrier wavelengths obtained from different parts of the infrared spectrum: 0.85 μm, 1.55 μm, and 10 μm. The transmitted carriers traveled through two different simulated fog conditions, radiation and advection, before being detected and decoded by the receiver. Then, the multiple carriers were combined and processed using two diversity schemes: equal gain and selective diversity. The study was conducted using simulation software PcModWin by onTar Corporation. The results show an average power reception improvement in tens of percent, by comparison to the use of a single carrier. Hence, the increase of the received power translates into a distance improvement of at least fifteen percent.

Alignment and tracking of a free-space optical communications link to a UAV

This paper investigates the ability of a mechanical gimbal to perform alignment and tracking of a free-space optical communications link between a ground station and an unmanned aerial vehicle. The repeatability and accuracy of a mechanical gimbal are experimentally analyzed in order to generate probability distribution functions for the gimbals performance. A simulation portion investigates the amount of divergence present in the laser beam of the communications link in the presence of atmospheric turbulence along with the scintillation index of the laser beam and the probability of the signal fading below a required threshold. The data from the experimental and simulation portions are further analyzed to verify the ability of a gimbal to provide acquisition and tracking functions for a ground-to-air link along with the expected geometric loss associated with such a communications link.

Digital micromirror device for optical scanning applications

Recent mechanical and nonmechanical optical scanning devices do not meet the fast scanning requirements for contemporary and emerging applications and can only steer optical beams over relatively narrow angles. A variety of important applications require fast optical scanning devices that can steer laser beams rapidly to an arbitrary location and with no moving parts. We introduce a new optical scanning technique that can be used to collimate and steer optical beams for precision alignment in either 2-D free-space optical (FSO) communications links or image scanners. This nonmechanical technique is capable of rapidly redirecting the optical beams to arbitrary locations without greatly sacrificing other parameters such as aperture size, efficiency, and scanning range. A digital micromirror device (DMD) beam-steering system was successfully demonstrated and exhibited better performance results when compared with other available systems.

Atmospheric turbulence effects on a wavelength diversified ground-to-UAV FSO link

The use of free-space optical (FSO) communications links are envisioned as a viable option for providing a temporary high-bandwidth communications link between a ground station and an unmanned aerial vehicle (UAV). The presence of atmospheric turbulence causes three different phenomena to occur, namely beam wander, scintillation and beam spread, each of which is a wavelength dependent phenomenon. In this paper, simulation tools are used to investigate the effects of atmospheric turbulence on a wavelength diversified ground-to-UAV FSO communications link. This paper compares the effects of atmospheric turbulence on three different wavelengths, 1.55 μm, 0.85 μm and 10 μm. Each of these wavelengths has different advantages depending on prevalent weather conditions and atmospheric turbulence conditions. Based on the effects of atmospheric turbulence on each wavelength, a wavelength diversity scheme is proposed in order to optimize the performance of the FSO link. The largest problem associated with establishing a ground-to-UAV FSO link is alignment and tracking of the FSO link. For this reason, the wavelength diversity scheme is further analyzed as a method to optimize link acquisition and tracking of the ground-to-UAV link by exploiting various characteristics of each wavelength.

Vehicle Identification Via Sparse Representation

In this paper, we propose a system using video cameras to perform vehicle identification. We tackle this problem by reconstructing an input by using multiple linear regression models and compressed sensing, which provide new ways to deal with three crucial issues in vehicle identification, namely, feature extraction, online vehicle identification database buildup , and robustness to occlusions and misalignment. The results show the capability of the proposed approach.

Improved reliability of free-space optical mesh networks through topology design

We propose a method for the topology design of free-space optical (FSO) mesh networks in order to enhance network reliability under a defined degree constraint of each FSO node. The methodology presented enlarges the minimum angle between adjacent links at each node. Simulation results show that, compared to other methods, the proposed algorithm not only provides a higher connectivity and lower delay for FSO networks but also makes the constructed FSO networks more tolerant in a dynamic environment.

A low-cost distributed control architecture for intelligent transportation systems deployment in the State of Oklahoma

Cost is a major issue for ITS deployment in Oklahoma. We introduce a novel distributed control architecture that has totally eliminated the need for an expensive monolithic traffic management center, thereby dramatically reducing the overall system cost. Analog and digital video streams from the various metro areas are seamlessly integrated by a fault tolerant, dynamically reconfigurable peer-to-peer network of low-cost geographically distributed ITS Consoles operating under the philosophy that any console should be able to control any system resource at any time.