An econometric analysis of the desktop computer hardware market

The purpose of this study was to compare six competing econometric models which depict the relationship between hardware characteristics and machine cost for the desktop computer market. The Box-Cox methodology and multiyear data were used to facilitate this comparison. The analysis validated that the Box-Cox methodology is a viable means for evaluating competing model formulations within the field of information systems research. The results were consistent with past research that suggested a double natural log model formulation for representing the functional relationships among variables when modeling machine cost as a function of hardware attributes. Further, the more complex power transformation model formulations suggested by the Box-Cox methodology did not significantly outperform the more traditional and simpler double natural log model. More specifically, the results indicated that variables related to primary memory and microchip tedinology have the largest impact on machine cost. Additionally, variables related to madiine connectivity, machine expandability, and year of observation were also found to be significant explanatory variables for machine cost

Peer Evaluation of Video Lab Reports in a Blended Introductory Physics Course

The Georgia Tech blended introductory calculus-based mechanics course emphasizes scientific communication as one of its learning goals, and to that end, we gave our students a series of four peer-evaluation assignments intended to develop their abilities to present and evaluate scientific arguments. Within these assignments, we also assessed students' evaluation abilities by comparing their evaluations to a set of expert evaluations. We summarize our development efforts and describe the changes we observed in student evaluation behavior.Comment: 4 pages, 1 table, 2 figures, submitted to Summer 2014 PERC Proceeding

The Initial State of Students Taking an Introductory Physics MOOC

As part of a larger research project into massively open online courses (MOOCs), we have investigated student background, as well as student participation in a physics MOOC with a laboratory component. Students completed a demographic survey and the Force and Motion Conceptual Evaluation at the beginning of the course. While the course is still actively running, we have tracked student participation over the first five weeks of the eleven-week course.Comment: Accepted to PERC Proceedings 201

Receptive Field Block Net for Accurate and Fast Object Detection

Current top-performing object detectors depend on deep CNN backbones, such as ResNet-101 and Inception, benefiting from their powerful feature representations but suffering from high computational costs. Conversely, some lightweight model based detectors fulfil real time processing, while their accuracies are often criticized. In this paper, we explore an alternative to build a fast and accurate detector by strengthening lightweight features using a hand-crafted mechanism. Inspired by the structure of Receptive Fields (RFs) in human visual systems, we propose a novel RF Block (RFB) module, which takes the relationship between the size and eccentricity of RFs into account, to enhance the feature discriminability and robustness. We further assemble RFB to the top of SSD, constructing the RFB Net detector. To evaluate its effectiveness, experiments are conducted on two major benchmarks and the results show that RFB Net is able to reach the performance of advanced very deep detectors while keeping the real-time speed. Code is available at https://github.com/ruinmessi/RFBNet.Comment: Accepted by ECCV 201

Nanoscale structure, dynamics and power conversion efficiency correlations in small molecule and oligomer-based photovoltaic devices

Photovoltaic functions in organic materials are intimately connected to interfacial morphologies of molecular packing in films on the nanometer scale and molecular levels. This review will focus on current studies on correlations of nanoscale morphologies in organic photovoltaic (OPV) materials with fundamental processes relevant to photovoltaic functions, such as light harvesting, exciton splitting, exciton diffusion, and charge separation (CS) and diffusion. Small molecule photovoltaic materials will be discussed here. The donor and acceptor materials in small molecule OPV devices can be fabricated in vacuum-deposited, multilayer, crystalline thin films, or spin-coated together to form blended bulk heterojunction (BHJ) films. These two methods result in very different morphologies of the solar cell active layers. There is still a formidable debate regarding which morphology is favored for OPV optimization. The morphology of the conducting films has been systematically altered; using variations of the techniques above, the whole spectrum of film qualities can be fabricated. It is possible to form a highly crystalline material, one which is completely amorphous, or an intermediate morphology. In this review, we will summarize the past key findings that have driven organic solar cell research and the current state-of-the-art of small molecule and conducting oligomer materials. We will also discuss the merits and drawbacks of these devices. Finally, we will highlight some works that directly compare the spectra and morphology of systematically elongated oligothiophene derivatives and compare these oligomers to their polymer counterparts. We hope this review will shed some new light on the morphology differences of these two systems

Removal of toxic contaminates from polluted soil and water via bioremediation utilizing bacillus spores [abstract]

Atrazine, a widely used herbicide in North America, is one of the known pollutants that pose a potential threat to human health. The addition of naturally occurring degradative bacteria that can remediate these pollutants has been promising. The soil bacterium Pseudomonas sp. strain ADP produces the enzyme AtzA which modifies atrazine to the benign hydroatrazine. However, the current use of bacteria in bioremediation is limited. These bacteria need to compete for nutrients with the native populations of microorganisms in the contaminated soil to survive and to maintain a degradative population. Bacterial endospores are naturally resistant to harmful environments, such as acidic soil, heat, and dessication; and have the ability to persist in soil for long periods of time. We wanted to utilize the Bacillus spore as a vehicle to deliver degradative enzymes, such as AtzA, into the soil and allow the tethered enzymes to persist over time. We utilized two methods for the tethering of enzymes to the spore surface. The first method being a genetic fusion of degradative enzymes to the exosporium of Bacillus endospores, and the second method being a chemical linkage to the outer layers of the Bacillus exosporium. INVENTOR(S): Brian M. Thompson; George C. Stewart; and Chun-Ho Lin CONTACT INFO: Harriet F. Francis, MS; J.D.; [email protected]; 573.884.0374 Per Stromhaug, Ph.D., MBA; [email protected]; 573.884.355

Nitric acid scavenging by mineral and biomass burning aerosols

The abundance of gas phase nitric acid in the upper troposphere is overestimated by global chemistry-transport models, especially during the spring and summer seasons. Recent aircraft data obtained over the central US show that mineral aerosols were abundant in the upper troposphere during spring. Chemical reactions on mineral dust may provide an important sink for nitric acid. In regions where the mineral dust abundance is low in the upper troposphere similar HNO3 removal processes may occur on biomass burning aerosols. We propose that mineral and biomass burning aerosols may provide an important global sink for gas phase nitric acid, particularly during spring and summer when aerosol composition in the upper troposphere may be greatly affected by dust storms from east Asia or tropical biomass burning plumes

Solar High-energy Astrophysical Plasmas Explorer (SHAPE). Volume 1: Proposed concept, statement of work and cost plan

The concept of the Solar High-Energy Astrophysical Plasmas Explorer (SHAPE) is studied. The primary goal is to understand the impulsive release of energy, efficient acceleration of particles to high energies, and rapid transport of energy. Solar flare studies are the centerpieces of the investigation because in flares these high energy processes can be studied in unmatched detail at most wavelenth regions of the electromagnetic spectrum as well as in energetic charged particles and neutrons