Department of Electrical and Computer Engineering

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GPU-OSDDA: A Bit-Vector GPU-based Deadlock Detection Algorithm for Single-Unit Resource Systems
(Taylor & Francis, 2015-09) Abell, Stephen; Nhan, Do; Lee, John J.; Department of Electrical and Computer Engineering
This article presents a GPU-based single-unit deadlock detection methodology and its algorithm, GPU-OSDDA. Our GPU-based design utilizes parallel hardware of GPU to perform computations and thus is able to overcome the major limitation of prior hardware-based approaches by having the capability of handling thousands of processes and resources, whilst achieving real-world run-times. By utilizing a bit-vector technique for storing algorithm ma- trices and designing novel, efficient algorithmic methods, we not only reduce memory usage dramatically but also achieve two orders of magnitude speedup over CPU equivalents. Additionally, GPU-OSDDA acts as an interactive service to the CPU, because all of the aforementioned computations and matrix management techniques take place on the GPU, requiring minimal interaction with the CPU. GPU-OSDDA is implemented on three GPU cards: Tesla C2050, Tesla K20c, and Titan X. Our design shows overall speedups of 6-595X over CPU equivalents.
Trash to Electricity
(Office of the Vice Chancellor for Research, 2013-04-05) Witte, Drew; Schubert, Peter J.
In 2009, America generated more than 243 million tons of trash, also known as Municipal Solid Waste (MSW). That generation rate was 275% greater than in 1960 when Americans generated 88.1 million tons of MSW. Today, landfills near urban areas are reaching their capacity and energy prices are soaring. Even after separating out recyclables from MSW, Americans’ trash still contains 11 MJ per kg. This energy value is stored as chemical energy in carbon based biomass and un-recyclable plastics. Many types of technologies exist that transform this trash energy into usable electrical energy. The status-quo for turning waste-to-energy is by combustion. There are 76 waste-to-energy combustion plants in the U.S. Another common way to transform waste to energy is by burning methane produced by landfills. Pyrolysis and gasification are two emerging technologies in the waste-to-energy field. These technologies are attractive because they are more controlled processes; therefore, pyrolysis and gasification is better for the environment and allows for greater rate of metal recycling after the process. Additionally, these emerging technologies show the potential to convert MSW into liquid fuels for transportation.
Hidden Wind Farms Potential for Residential Households Having Roofmounted Wind Arrester
(IEEE, 2015) Amini, Amin; Kamoona, Mustafa; Department of Electrical and Computer Engineering, Purdue School of Engineering and Technology
Small-scale energy-generating systems are being increasingly integrated into built environment, and the use of renewable energies is now spreading to old towns in developing countries. Despite the promise of free energy, the high-tech appearance of the harnessing tools of renewables has provoked criticism because of the incompatibility with the cultural/environmental characteristics of older towns in Iran. This paper presents a new concept of novel hidden wind farms in the residential households of Iranian desert-edge towns with roof-mounted wind-arresters. The results of this study show that a hidden wind farm integrated into old towns with the potential of tourism can eliminate the concern over the visibility and bird collisions as well as the use of land. In the present study, the old city of Ardakan, Yazd, with an arid climate located at the edge of a desert in the center of Iran, is selected as target case study. Calculations show that the application of one small-scale wind turbine per wind-arrester across the town can generate approximately 2.90 GWh a year. Moreover, the proposed concept could also be applied in other countries such as Afghanistan, Egypt, Pakistan, Iraq, UAE and some African countries.
Harmonic Analysis and Practical Implementation of a Two-Phase Microgrid System
(IEEE, 2015-03) Alibeik, Maryam; dos Santos, Euzeli C., Jr.; Yang, Y.; Wang, X.; Blaabjerg, F.; Department of Electrical and Computer Engineering, School of Engineering and Technology
This paper analyzes the harmonic contents of a non-linear load connected to a two-phase microgrid system. Although having the same harmonic content as the single-phase power system when supplying a non-linear load under balanced conditions, the two-phase microgrid system presents the following advantages: 1) constant power through the power line at the balanced condition; 2) two voltages i.e., line-to-line and phase voltages, available by using a three wire system; 3) optimized voltage utilization compared to a three-phase system; and 4) a direct connection of both symmetrical two-phase and single-phase electrical machines. This paper presents an approach for analyzing the harmonics of a two-phase non-linear load in a balanced and unbalanced cases. The mathematical model for the symmetrical component of an unbalanced two-phase system has also been presented in this paper. Finally, a practical implementation of the two-phase system has been performed, where different types of loads are connected to the two-phase power line to test the voltage control performance.
Solar Panel Efficacy vs. Altitude in an Urban City Environment
(American Society for Engineering Education, 2015-06) Elkhatib, Wiaam; Schubert, Peter J.; Zusack, Steven; Rosales, Emily; Stanforth, Austin; Department of Engineering Technology, Purdue School of Engineering and Technology, IUPUI
In light of current issues of global warming, pollution, and fossil fuel depletion, alternative and renewable energy sources are increasing in desirability. Among these, solar energy is a popular option. However, it is hypothesized that particulate pollution in urban atmospheres limits photovoltaic (PV) efficacy both in accumulated grime and also in altitude via sunlight attenuation. The objective of this study is to measure photovoltaic power output near solar noon at multiple heights within a city environment to determine the influence of altitude on power output. Building rooftops between 200 and 800 feet were sampled simultaneously with a ground level control within a broad university courtyard. Days having no cloud cover were preferentially chosen. Other factors to consider include the “urban heat island” effect and water vapor in the air, so meteorological parameters were measured simultaneously to reduce confounding errors. Multiple repeated tests were conducted to increase confidence, especially since the effect was anticipated to be small in magnitude. Additionally, students affiliated with the project completed surveys to assess how their involvement impacted their learning of experimental design and procedures. Students who chose not to participate were also surveyed to provide a control group. Comparisons in the data are drawn on a power to ambient light ratio to minimize bias between the PV panels used for testing. Preliminary analysis indicates the effect of altitude is minimal within the parameters of this study. Analysis of our data did not significantly demonstrate an improvement in solar productivity at increased altitudes. However, the rigorous test methodology developed provides a means for quantitative analysis in cities with greater levels of pollution relative to the city tested. The survey of students indicated a positive correlation between participation in the project and the amount students felt they learned during the process.
Bio-Hydrogen Refueling Station
(Office of the Vice Chancellor for Research, 2016-04-08) Schubert, Peter J.
Hydrogen fuel cell cars are now available for lease and for sale. Renewable hydrogen fuel can be produced from water via electrolysis, or from biomass via gasification. Electrolysis is powerhungry with high demand from solar or wind power. Gasification, however, can be energy selfsufficient using a recently-patented thermochemical conversion technology known as Indirectly- Heated Pyrolytic Gasification. I-HPG produces a tar-free syngas from non-food woody biomass. This means the balance of plant can be small, so the overall system is economical at modest sizes. This makes it possible to produce renewable hydrogen from local agricultural residues; sufficient to create distributed refueling stations wherever there is feedstock. This work describes the specifics of a novel bio-hydrogen refueling station whereby the syngas produced has much of the hydrogen extracted with the remainder powering a generator to provide the electric power to the I-HPG system. Thus the system runs continuously. When paired with another new technology, moderate-pressure storage of hydrogen in porous silicon, there is the potential to also power the refueling operation. Such systems can be operated independently. It is even possible to design an energy self-sufficient farm where all electric power, heat, and hydrogen fuel is produced from the non-food residues of agricultural operations. No water is required, and the carbon footprint is negative, or at least neutral.
Brownfield remediation powered by renewable energy
(Office of the Vice Chancellor for Research, 2016-04-08) Schubert, Peter J.
Subsurface contaminant plumes are a plague upon the earth. Some 1900 plumes remain after the go-fast atom bomb projects of the Cold War. Countless gasoline station sites dot our cities, leaching heavy metals and chlorinated solvents into drinking water. Superfund-type cleanup is so expensive that many sites languish while toxins continue to spread throughout the ecosystem. Federal funding for remediation research stopped 15 years ago. The only solution now is to move bad soil from one location to another. New advances in stem cell manipulation offer promise to clean up solvent-infused earth with a minimum of excavation at greatly reduced costs. Dielectrophoresis is the means by which polar molecules, in a matrix having a different dielectric constant, can be made to migrate along electric field gradients. A unique configuration called “pills and pillars” facilitates remediation of solvents. Electric field gradients originating in the deeply-driven “pillars” motivate solvents molecules towards the slightly-buried “pill”. When powered by renewable sources, such as solar panels, contaminants within a 1000 m3 volume can be concentrated within a 1 m3 volume at the pill, and then removed for disposal in a certified toxic waste repository. The pills and pillars are easily extracted for removal to a new site every 40 days. The solar panels are man-portable so that a single capital expenditure of a truckmounted kit can serve multiple sites simultaneously, and sequentially. The low labor overhead, the greatly reduced excavation, and the re-use of hardware contribute to make this novel method of brownfield remediation far cheaper than traditional, presently-available methods. Computer simulations including both vadose zone diffusion (natural spreading out) and drift via dielectrophoresis, demonstrate the effectiveness of this approach. The next research step is to build a benchtop model to validate the simulation model, followed by field trials with partners in the environmental remediation industry.
Solar power satellite with no moving parts
(Office of the Vice Chancellor for Research, IUPUI, 2016-04-08) Schubert, Peter J.
The only solution to the global energy mess is sunlight captured in space. No other technology scales as well, and is as clean as Space Solar Power. Best of all, this is baseload power – “always on” – without the intermittency which will always plague ground-based solar and wind. Although invented in 1968, SSP designs have been impractical until now. A novel design architecture, relying on use of materials already in space, enables SSP at costs competitive with existing baseload power sources. And all this without greenhouse gas emissions. This work describes the technology and economics. The “tin can” solar power satellite is comprised of a cylindrical shell of solar panels. This configuration has integral thermal management by using the non-illuminated portions of the shell as a radiating heat shield, maintaining the solar cells within workable temperature ranges. The tethers holding the shell to the central conductor spire present a complex radiative environment which is studied further herein to obtain a more precise measurement of high and low temperature limits. Heat generated by the transmitting antenna and its power electronics is also studied to understand its impact on the requirements imposed on components and subsystems. Achieving a slow rotation of a very large diameter cylindrical shell with minimal internal strength interacts with the assembly process through tradeoffs between propellant, assembly jigs, and construction spacecraft. Vibrations induced in the cylindrical shell are studied including transient behavior during spin-up. The panel-to-panel forces expected during spin-up, and during on-going operations as gravity gradients excite low-frequency modes are studied in order to derive specifications for linkage rotation and strength. Finally, the results of imperfect assembly, lost parts, and meteorite strikes are investigated to assess risk to other spacecraft. Solar wind pressure is evaluated to determine station-keeping requirements. Assembly in an orbit slightly higher than GEO may be selected to minimize collateral damages, and means of adjusting the orbit are studied to derive overall architecture propellant requirements, anticipating a mixture of in situ propellant options versus earth-sourced propellants. This work charts a pathway to the ultimate energy source for all mankind for all time to come.
Pedestrian Detection based on Clustered Poselet Models and Hierarchical And-Or Grammar
(IEEE, 2015-04) Li, Bo; Chen, Yaobin; Wang, Fei-Yue; Department of Electrical and Computer Engineering, Purdue School of Engineering and Technology
In this paper, a novel part-based pedestrian detection algorithm is proposed for complex traffic surveillance environments. To capture posture and articulation variations of pedestrians, we define a hierarchical grammar model with the and-or graphical structure to represent the decomposition of pedestrians. Thus, pedestrian detection is converted to a parsing problem. Next, we propose clustered poselet models, which use the affinity propagation clustering algorithm to automatically select representative pedestrian part patterns in keypoint space. Trained clustered poselets are utilized as the terminal part models in the grammar model. Finally, after all clustered poselet activations in the input image are detected, one bottom-up inference is performed to effectively search maximum a posteriori (MAP) solutions in the grammar model. Thus, consistent poselet activations are combined into pedestrian hypotheses, and their bounding boxes are predicted. Both appearance scores and geometry constraints among pedestrian parts are considered in inference. A series of experiments is conducted on images, both from the public TUD-Pedestrian data set and collected in real traffic crossing scenarios. The experimental results demonstrate that our algorithm outperforms other successful approaches with high reliability and robustness in complex environments.
A Dynamic Threshold Decryption Scheme Using Bilinear Pairings
(2015-11) King, Brian; Department of Electrical and Computer Engineering, Purdue School of Engineering and Technology
A dynamic threshold sharing scheme is one that allows the set of participants to expand and contract. In this work we discuss dynamic threshold decryption schemes using bilinear pairing. We discuss and analyze existing schemes, demonstrate an attack and construct a signi cantly more efficient secure scheme.

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