Engineering Commons^™

Are We Ready To Live In An Uberveillance Society?, Uow Media Unit, Alexander Hayes, Katina Michael

Alexander Hayes Mr.

When Google Glass hits stores later this year, not only will it transform sunglasses from fashion accessory to wearable technology, it will cause a social revolution, says IEEE Technology & Society Magazine editor in chief, Associate Professor Katina Michael.

The Sci-Fi-looking, internet-connected eyewear can do everything a mobile phone can do (and more) with a simple voice command.

Beyond the obvious functions – snapping photos, recording video, send text messages and searching the internet – some of the most exciting uses include biofeedback (monitor your heart rate on your morning run), instruction (stream step-by-step video tutorials) and navigation (map out …

System Impact Of Silicon Carbide Power Electronics On Hybrid Electric Vehicle Applications, Burak Ozpineci

Burak Ozpineci

The emergence of silicon carbide- (SiC-) based power semiconductor switches with their superior features compared with silicon (Si) based switches has resulted in substantial improvements in the performance of power electronics converter systems. These systems with SiC power devices are more compact, lighter, and more efficient, so they are ideal for high-voltage power electronics applications including hybrid electric vehicle (HEV) power converters. In this dissertation, first, a power supply converter and a traction drive converter of an HEV are selected and then, the impact of SiC-based power devices on these converters is investigated. Reductions in heatsink size and device losses …

Conditions For Capacitor Voltage Regulation In A Five-Level Cascade Multilevel Inverter: Application To Voltage-Boost In A Pm Drive, John Chiasson, Burak Ozpineci, Zhong Du, Leon Tolbert

Burak Ozpineci

A cascade multilevel inverter is a power electronic device built to synthesize a desired AC voltage from several levels of DC voltages. Such inverters have been the subject of research in the last several years, where the DC levels were considered to be identical in that all of them were either batteries, solar cells, etc. Similar to previous results in the literature, the work here shows how a cascade multilevel inverter can be used to obtain a voltage boost at higher speeds for a three-phase PM drive using only a single DC voltage source. The input of a standard three-leg …

A Five-Level Three-Phase Hybrid Cascade Multilevel Inverter Using A Single Dc Source For A Pm Synchronous Motor Drive, John N. Chiasson, Burak Ozpineci, Leon M. Tolbert

Burak Ozpineci

The interest here is in using a single DC power source to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously maintain the regulation of the capacitor voltage while achieving an output voltage waveform which is 25% higher than that obtained using a standard 3-leg inverter by itself.

Fundamental Frequency Switching Strategies Of A Seven-Level Hybrid Cascaded H-Bridge Multilevel Inverter, Zhong Du, Leon Tolbert, Burak Ozpineci, John Chiasson

Burak Ozpineci

This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n − 1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose …

Pre-Amplifiers For A 15-Tesla Magnetic Resonance Imager, Chin-Leong Lim, Peter Serano, Jerome L. Ackerman

Chin-Leong Lim

High-field magnetic resonance imagers (MRI) give better signal-to-noise ratio (SNR) and image contrast. However clinical MRIs are currently limited to 3 Tesla (T) magnetic field strength. To create an uncommon 15 T scanner for research use, we evaluated several low-cost, intended for wireless communication, GaAs enhancement-mode pseudomorphic high electron mobility transistors (ePHEMT) in the critical preamplifier slot. This paper reports the experimental results that were obtained at both module and system levels. When evaluated in our prototype 15 T scanner front-end’s preamplifier slot, the candidate devices’ sub 1dB noise figures enabled image SNR ~ 110 in a water phantom (test …

Limiting And Transient Performances Of A Low Loss Pin-Schottky Limiter, Chin-Leong Lim

Chin-Leong Lim

The main cause of loss in the PIN-Schottky limiter is the diodes’ parasitic capacitances. Techniques to counter the parasitic capacitances include using bare chip, air cavity packaging, diode stacking, mesa construction, isolating the Schottky diode from the signal path and connecting the diodes to a low impedance node. But the aforementioned techniques either sacrifice cost, manufacturability, size, performances or thermal ruggedness. To reduce loss in the PIN-Schottky limiter, we re-configured its parasitics into a low pass ladder network. This paper reports on the new configuration’s changed large signal and transient performances. We observed improved isolation at 0.9 and 2.4 GHz, …

Computational Aspects Of The Three-Dimensional Feature-Scale Simulation Of Silicon-Nanowire Field-Effect Sesnsors For Dna Detection, Clemens Heitzinger, Gerhard Klimeck

Gerhard Klimeck

In recent years DNA-sensors, and generally biosensors, with semiconducting transducers were fabricated and characterized. Although the concept of so-called BioFETs was proposed already two decades ago, its realization has become feasible only recently due to advances in process technology. In this paper a comprehensive and rigorous approach to the simulation of silicon-nanowire DNAFETs at the feature-scale is presented. It allows to investigate the feasibility of single-molecule detectors and is used to elucidate the performance that can be expected from sensors with nanowire diameters in the deca-nanometer range. Finally the computational challenges for the simulation of silicon-nanowire DNAsensors are discussed.

Low Rank Approximation Method For Efficient Green's Function Calculation Of Dissipative Quantum Transport, Lang Zeng, Yu He, Michael Povolotskyi, Xiao Yan Liu, Gerhard Klimeck, Tillmann Kubis

Gerhard Klimeck

In this work, the low rank approximation concept is extended to the non-equilibrium Green’s function (NEGF) method to achieve a very efficient approximated algorithm for coherent and incoherent electron transport. This new method is applied to inelastic transport in various semiconductor nanodevices. Detailed benchmarks with exact NEGF solutions show (1) a very good agreement between approximated and exact NEGF results, (2) a significant reduction of the required memory, and (3) a large reduction of the computational time (a factor of speed up as high as 150 times is observed). A non-recursive solution of the inelastic NEGF transport equations of a …

Experimental And Theoretical Study Of Polarization-Dependent Optical Transitions In Inas Quantum Dots At Telecommunication-Wavelengths (1300-1500 Nm), Muhammad Usman, Susannah Heck, Edmund Clarke, Peter Spencer, Hoon Ryu, Ray Murray, Gerhard Klimeck

Gerhard Klimeck

observed, in contrast to recent reports for single QDJOURNAL OF APPLIED PHYSICS 109, 104510 (2011)The design of some optical devices, such as semiconductor optical amplifiers for telecommunication applications, requires polarization-insensitive optical emission at long wavelengths (1300–1550 nm). Self-assembled InAs/GaAs quantum dots (QDs) typically exhibit ground state optical emissions at wavelengths shorter than 1300 nm with highly polarization-sensitive characteristics, although this can be modified by the use of low growth rates, the incorporation of strain-reducing capping layers, or the growth of closely-stacked QD layers. Exploiting the strain interactions between closely stacked QD layers also affords greater freedom in the choice of …

Computing Entries Of The Inverse Of A Sparse Matrix Using The Find Algorithm, S Li, Gerhard Klimeck, E Darve

Gerhard Klimeck

An accurate and efficient algorithm, called fast inverse using nested dissection (FIND). for computing non-equilibrium Green's functions (NEGF) for nanoscale transistors has been developed and applied in the simulation of a novel dual-gate metal-oxide-semi conductor field-effect transistor (MOSFET) device structure. The method is based on the algorithm of nested dissection. A graph of the matrix is constructed and decomposed using a tree structure. An upward and downward traversal of the tree yields significant performance improvements for both the speed and memory requirements, compared to the current state-of-the-art recursive methods for NEGF. This algorithm is quite general and can be applied …

Design Concepts Of Terahertz Quantum Cascade Lasers: Proposal For Terahertz Laser Efficiency Improvements, Tillmann Kubis, Saumitra Raj Mehrotra, Gerhard Klimeck

Gerhard Klimeck

Conceptual disadvantages of typical resonant phonon terahertz quantum cascade lasers 􏰎THz-QCLs􏰍 are analyzed. Alternative designs and their combination within a concrete device proposal are discussed to improve the QCL performance. The improvements are 􏰎1􏰍 indirect pumping of the upper laser level, 􏰎2􏰍 diagonal optical transitions, 􏰎3􏰍 complete electron thermalization, and 􏰎4􏰍 materials with low effective electron masses. The nonequilibrium Green’s function method is applied to predict stationary electron transport and optical gain. The proposed THz-QCL shows a higher optical gain, a lower threshold current, and a higher operation temperature. Alloy disorder scattering can worsen the QCL performance.

Probabilistic Verification Of Coordinated Multi-Robot Missions, Sagar J. Chaki, Joseph A. Giampapa

Joseph Andrew Giampapa

Robots are increasingly used to perform a wide variety of tasks, especially those involving dangerous or inaccessible locations. As the complexity of such tasks grow, robots are being deployed in teams, with complex coordination schemes aimed at maximizing the chance of mission success. Such teams operate under inherently uncertain conditions -- the robots themselves fail, and have to continuously adapt to changing environmental conditions. A key challenge facing robotic mission designers is therefore to construct a mission -- i.e., specify number and type of robots, number and size of teams, coordination and planning mechanisms etc. -- so as to maximize …

Efficient Processing Of System Scenarios In Statistical And Machine Learning Studies For Power System Operational And Investment Planning, Venkat Kumar Krishnan

Venkat Kumar Krishnan

Power System security assessment and the associated planning studies are becoming more and more complex with ever increasing uncertainties in all time horizons. An effective means of performing operational and investment planning studies of network limitations associated with static or dynamic post-disturbance performance problems has been to take a Monte Carlo simulation based approach. The approach harnesses computing power to develop a database of post-contingency response over a wide range of different operating conditions, and then apply statistical or machine learning methods to extract useful planning and operational information from the database. Key to the machine learning based planning approach …

Impact Of Renewable Power Integration On Vq Stability Margin, H. W. K. M. Amarasekara, Lasantha Meegahapola, Sarath Perera, Ashish Agalgaonkar

Dr Lasantha G Meegahapola

With the increasing number of grid connected renewable energy sources in power systems, the requirements for in-depth studies to characterise the dynamics of power systems have also intensified. In this paper, the impact of renewable power generators on power system voltage stability is analysed. As the renewable power penetration increases, having adequate levels of reactive power generation in power systems for voltage support is a major challenge. Therefore, in this work, special attention was placed on VQ instability to investigate static voltage stability of a test network embedded with renewable power generation. The impact of different control strategies associated with …

Non-Coding Rna Covariance Model Combination Using Mixed Primary-Secondary Structure Alignment, Jennifer Smith

Jennifer A. Smith

Covariance models are very effective for finding new members of non-coding RNA sequence families in genomic data. However, the computation burden of applying CM-based search algorithms can be prohibitive. When annotating the genome of a newly sequenced organism it is usually desired to search the sequence data using a large number of ncRNA families. Computational burden can be reduced if the families are clustered into statistically similar models and a single cluster-average representative model produced. The database is then searched with the representative model for each cluster at a relatively low detection threshold. The output of this pre-filtered database is …

Distribution Free Prediction Interval For Uncertainty Quantification In Remaining Useful Life Prediction, Huimin Chen

Huimin Chen

Remaining useful life (RUL) prediction is an important component for system health monitoring and prognosis. Ideally, one expects the prediction algorithm to provide the complete distribution of the RUL prediction over time taking various uncertainties into account. However, the dynamic model being used to characterize state estimation and future loading uncertainties is often simplified through various approximations, leading to non-credible predicted distribution. Nevertheless, certain algorithm may only provide a point estimate of the RUL, making it difficult to quantify the uncertainty of the prediction. In this paper, we focus on interval prediction with high probability that guarantees finite sample validity …

Energy Modeling Of Wireless Sensor Nodes Based On Petri Nets, Ali Shareef, Yifeng Zhu

Yifeng Zhu

Energy minimization is of great importance in wireless sensor networks in extending the battery lifetime. Accurately understanding the energy consumption characteristics of each sensor node is a critical step for the design of energy saving strategies. This paper develops a detailed probabilistic model based on Petri nets to evaluate the energy consumption of a wireless sensor node. The model factors critical components of a sensor node, including processors with emerging energy-saving features, wireless communication components, and an open or closed workload generator. Experimental results show that this model is more flexible and accurate than Markov models. The model provides a …

Energy Modeling Of Processors Inwireless Sensor Networks Based On Petri Nets, Ali Shareef, Yifeng Zhu

Yifeng Zhu

Power minimization is a serious issue in wireless sensor networks to extend the lifetime and minimize costs. However, in order to gain an accurate understanding of issues regarding power minimization, modeling techniques capable of accurately predicting energy consumption are needed. This paper demonstrates that Petri nets are a viable option of modeling a processor. In fact, this paper shows that the Petri nets’ accuracy surpasses a Markov model utilizing supplementary variables to account for constant delays.

Effective Stochastic Modeling Of Energy-Constrained Wireless Sensor Networks, Ali Shareef, Yifeng Zhu

Yifeng Zhu

Energy consumption of energy-constrained nodes in wireless sensor networks (WSNs) is a fatal weakness of these networks. Since these nodes usually operate on batteries, the maximum utility of the network is dependent upon the optimal energy usage of these nodes. However, new emerging optimal energy consumption algorithms, protocols, and system designs require an evaluation platform. This necessitates modeling techniques that can quickly and accurately evaluate their behavior and identify strengths and weakness. We propose Petri nets as this ideal platform. We demonstrate Petri net models of wireless sensor nodes that incorporate the complex interactions between the processing and communication components …

Localization Using Extended Kalman Filters In Wireless Sensor Networks, Ali Shareef, Yifeng Zhu

Yifeng Zhu

Introduction: Localization arises repeatedly in many location-aware applications such as navigation, autonomous robotic movement, and asset tracking. Analytical localization methods include triangulation and trilateration. Triangulation uses angles, distances, and trigonometric relationships to locate an object. Trilateration, on the other hand, uses only distance measurements to identify the position of the target.

Efficient Superposition Of Communication And Radar Waveforms (Raytheon), Anton Frolenkov, Vidie Pong, Sasha Sproch, Amy Whitcombe

Sasha A Sproch

The goal of the Raytheon-Olin SCOPE team was to identify pairs of communication and radar waveforms that could be superimposed through a single nonlinear amplifier while still fulfilling primary communications and radar functions. The team investigated candidate performance using hardware experimentation and industry-standard simulation. The results of this study begin to define the conditions for successful simultaneous communications and radar transmission through a single non-linear amplifier.

Impact Of Capacity Value Of Renewable Energy Resources On Raps System Energy Management, Lasantha Meegahapola, Y Tan, K Muttaqi

Dr Lasantha G Meegahapola

Renewable energy resources are widely being utilised in remote area power supply (RAPS) systems. The capacity value of renewable energy resources in a RAPS system indicates the ability of renewable energy resources to serve the load demand in the RAPS systems. In this paper, the impact of capacity value of renewable resources on energy management of a RAPS system, while maintaining system reliability, is investigated. It is revealed that capacity value of renewable energy resources has direct influence on RAPS system energy management. By utilising storage in conjunction with renewable energy resources, the RAPS system can cater load demand while …

Power Quality Emission Assessment Of Photovoltaic Inverters Based On Iec Technical Report 61000-3-15:2011, Lasantha Meegahapola, D Perera, P Ciufo, S Perera

Dr Lasantha G Meegahapola

The International Electrotechnical Committee Technical Report IEC 61000-3-15:2011 provides electromagnetic compatibility requirements and test conditions for distributed generators up to 75 A per phase. In the current research, two commercially available photovoltaic (PV) inverters up to the capacity of 3600 W were tested following the guidelines proposed in IEC 61000-3-15 in relation to low order harmonic emission and flicker emission. In addition, the harmonic and flicker emission behaviour of the PV inverters were investigated under varying irradiation conditions. Both PV inverters were observed to comply with the emission requirements prescribed by the technical report under most conditions except for even …

A Droop Control Based Load Sharing Approach For Management Of Renewable And Non-Renewable Energy Resources In A Remote Power System, Lasantha Meegahapola, Y Tan, K Muttaqi

Dr Lasantha G Meegahapola

Droop control is a load sharing strategy applied in conventional power systems. In this paper, droop control strategy has been adopted for the generators in a remote area power supply (RAPS) system in order to share active and reactive power load based on the rated capacities of the generators. Different characteristics of conventional and inverter-based energy resources make it difficult to share load in proportion to the rated capacities of the generators in a RAPS system. Therefore, this paper investigates the load sharing performance of different combinations of conventional and inverter-based energy resources in RAPS systems. The study scenarios investigated …

Planning For Long Haul- Investment Strategies For National Energy And Transportation Infrastructures,” Ieee Power And Energy, James Mccalley, Venkat Krishnan

Venkat Kumar Krishnan

No abstract provided.

Balanced Uhf Lna Simplifies Cell Towers, Chin-Leong Lim

Chin-Leong Lim

Cellular basestations' low noise amplifiers (LNA) must have input impedances that are closely matched to the antennas. Unfortunately, the amplifier devices cannot be conjugate matched without sacrificing their noise performances. Current solutions such as the isolator and the balanced LNA can satisfactorily solve the matching problem but at the expense of increased cost, weight and size. On the other hand, the confined space atop cellular towers makes the current solutions unattractive. To shrink the balanced LNA for cellular infrastructure service, we pair a highly integrated dual-amplifier MMIC with miniature multilayer couplers. This MMIC also achieves the distinction of being the …

Brief Comparison Between 8051 And Avr, Ata Jahangir Moshayedi

Ata Jahangir Moshayedi

Brief comparison between 8051 and AVR

Magnetic And Microwave Properties Of Cofe/Ptmn/Cofe Multilayer Films, C. Pettiford, A. Zeltser, S. Yoon, V. Harris, C. Vittoria, N. Sun

Nian X. Sun

CoFe/PtMn/CoFe films were deposited on seed layers of Ru or NiFeCr with CoFe film compositions being either Co-10 at. %Fe or Co-16 at. %Fe. Eight periods of the CoFe/PtMn/CoFe trilayers were also prepared. The magnetic properties and ferromagnetic resonance (FMR) of these films were characterized with vibrating-sample magnetometer, and field-sweep FMR system at X band (∽9.5 GHz). The Ru-seeded CoFe/PtMn/CoFe sandwich films show excellent magnetic softness with a low hard axis coercivity of 2-4 Oe, an easy axis M_r/M_s of >98%, and a significantly enhanced in-plane anisotropy of 57-123 Oe when CoFe layer thickness is above 200 …

Room Temperature Magnetism In Semiconducting Films Of Zno Doped With Ferric Ions, S. D. Yoon, Y. J. Chen, D. Heiman, A. Yang, N. Sun, C. Vittoria, V. G. Harris

Nian X. Sun

Films consisting of Zn₁₋ₓFeₓO were prepared by alternating-target laser ablation deposition. The Fe doping levels ranged from x=0.016 to 0.125 at. %. X-ray diffraction and energy dispersive x-ray spectroscopy measurements showed only (002n) reflections of the ZnO host and confirmation of the Fe concentration, respectively. For films grown on (001) Al₂O₃ at 300 K, room temperature average saturation magnetization, < 4πMs >, measured from superconducting quantum interference device (SQUID) hysteresis loops for x=0.125 ± 0.025 was 172 G. Although SQUID measurements were sensitive to the average value of the saturation magnetization, ferrimagnetic resonance measurements appeared to be sensitive only to the saturation …