Supplier assessment and selection is critical in the world of international logistics and supply chain management. Despite this criticality, related processes and methodologies are largely subjective and anecdotal. A more quantitative empirical approach is needed. Improving the way government agencies and commercial businesses select suppliers can clearly result in cost savings, better schedule adherence, and higher-quality products. A key aspect of supplier selection for large government projects is effective evaluation and use of suppliers' past performance data. However, organisations continue to search for better ways to adequately assess and utilise that data. This study uncovers new ways to more effectively use the United States government's primary supplier performance evaluation system, called the Contractor Performance Assessment Reporting System. Based on the results of the study, a strong correlation has been shown to exist between contractors' past and subsequent scores in terms of cost, schedule, and technical performance. The findings further indicate that the global commercial logistics community can use similar quantitative measures of contractors' past performance to improve the effectiveness of their own supplier selection decisions.

Optical down-conversion techniques have become an increasingly popular architecture to realize Multi-band Enterprise Terminals (MET), Synthetic Aperture Radar (SAR), Optical Arbitrary Waveform Generation (OAWG), RF Channelizers and other technologies that need rapid frequency agile tunability in the microwave and millimeter RF bands. We describe recent SFDR, NF, Gain, and Noise modeling and measurements of Erbium-doped-fiber amplified analog RF optical links implementing all-optical down-conversion and balanced photodiode receivers. We describe measurements made on our newly designed extensive test-bed utilizing a wide array of high powered single and balanced photodiodes, polarization preserving output LN modulators, EAMs, LIMs, tunable lasers, EDFAs, RF Amplifiers, and other components to fully characterize direct and coherent detection techniques. Additionally, we compare these experimental results to our comprehensive MATLAB system modeling and optimization software tools.

Antennas in congested RF environments are susceptible to co-site interference. Interfering signals are usually stronger than the signal of interest by several orders of magnitude, and offset in frequency but within the bandwidth of the antenna. We present an optical technique to mitigate interfering signals by generating nulls at specific frequencies using a dual-output Mach-Zehnder modulator, optical delay, and balanced detectors. We demonstrate the nulling of interfering signals by over 40 dB without attenuating the signal of interest.

The use of optical interferometry within an optical waveguide structure for null frequencies is well understood. We demonstrate a useful application of a related technique using unbalanced outputs of a dual output Mach-Zehnder modulator combined with a balanced detector to provide frequency agile, dynamic co-site interference mitigation. We will show the extreme wideband performance of this all optical solution by rejecting interferer frequencies by over 40 dB. We initially apply this technique to the challenging sub-octave microwave communications environment and suggest that the utility of this technique actually improves up into the millimeter bands.

B-PPM formatting for trans-atmospheric optical communication is compared experimentally to OOK (NRZ) at a single channel data rate of 1.25Gbps in deep fading conditions. Unlike low data rate transmission using Wary PPM formatting, high-speed B-PPM formatting does not benefit from the theoretical improvement that has been realized at low data rate. Although B-PPM can indeed benefit from a threshold set to near-zero, the high speed transmission precludes the implementation of a traditional Maximum Likelihood Detection circuit that compares the integrated power of each slot. At high speed, one has to rely on signal strength alone within the bit period which degrades the contrast between a "one" and a "zero." Moreover, the need for twice the bandwidth for B-PPM significantly limits available components such as APDs. More important, however, is the fact that during deep fades clock resynchronization dominates at high data rate. The primary question to be addressed is: Does B-PPM formatting really provide sufficient margin compared to NRZ to merit its use in deep fading atmospheric conditions? By building a special dual transceiver system, we have been able to propagate both B-PPM and NRZ formatted signals co-linearly on two C-band wavelengths centered close to 1550nm. Under field testing we measured the BER, including signal resynchronization, using special InGaAs, high-speed, multimode pigtailed, APD-based detectors in the receiver. The data were collected on fully instrumented horizontal paths of I km and 500m with C-n(2) [m(-2/3)] ranging from 10(-15) to 10(-13).

Intensity fluctuations from a 532nm CW laser source were collected over an outdoor 1km path, 2m above the ground, with three different receiving apertures. The scintillation index was found for each receiving aperture and recently developed theory for all regimes of optical turbulence was used to infer three atmospheric parameters, Cn2, l0, and L0. Parallel to the three-aperture data collection was a commercial scintillometer unit which reported Cn2 and crosswind speed. There was also a weather station positioned at the receiver side which provided point measurements for temperature and wind speed. The Cn2 measurement obtained from the commercial scintillometer was used to infer l0, L0, and the scintillation index. Those values were then compared to the inferred atmospheric parameters from the experimental data. Finally, the optimal aperture sizes for data collection with the three-aperture receiver were determined.

We report on a set of measurements made in December 2005 by researchers from the University of Central Florida, SPAWAR's Innovative Science and Technology Experiment Facility (ISTEF), Harris Corporation, NASA Kennedy Space Center, and Northrop Grumman. The experiments were conducted on the Shuttle Landing Facility (SLF) at Kennedy Space Center (KSC) over terrestrial paths of 1, 2, and 5 km. The purpose of the experiments was to determine the atmospheric-induced beam spreading and beam wander at various ranges. Two lasers were used in the experiments. Both were a pulsed 1.06 mu m laser; however, one was single-mode and the other was multi-mode. Beam profiles were recorded near the target position. Simultaneous measurements of C-n(2), wind speed and direction, humidity, visibility, temperature, and surface temperature profiles were all recorded.

The Shuttle Landing Facility runway at the Kennedy Space Center in Cape Canaveral, Florida is almost 5 km long and 100 m wide. Its homogeneous environment makes it a unique and ideal place for testing and evaluating EO systems. An experiment, with the goal of characterizing atmospheric parameters on the runway, was conducted in June 2005. Weather data was collected and the refractive index structure parameter was measured with a commercial scintillometer. The inner scale of turbulence was inferred from wind speed measurements and surface roughness. Values of the crosswind speed obtained from the scintillometer were compared with wind measurements taken by a weather station.

We report on measurements made at the Shuttle Landing Facility (SLF) runway at Kennedy Space Center of receiver aperture averaging effects on a propagating optical Gaussian beam wave over a propagation path of 1,000 m. A commercially available instrument with both transmit and receive apertures was used to transmit a modulated laser beam operating at 1550 nm through a transmit aperture of 2.54 cm. An identical model of the same instrument was used as a receiver with a single aperture that was varied in size up to 20 cm to measure the effect of receiver aperture averaging on Bit Error Rate. Simultaneous measurements were also made with a scintillometer instrument and local weather station instruments to characterize atmospheric conditions along the propagation path during the experiments.