Engineering Commons^™

Wideband Voltage Variable Attenuator With Fewer Components, Chin-Leong Lim

Chin-Leong Lim

RF/microwave amplifying devices have unit-to-unit gain variability. So, in some critical applications such as the low noise amplifier (LNA) in cellular basestations, the gain has to be adjusted in production using a voltage-variable attenuators (VVA). Constant impedance VVAs such as the PI and the bridged-TEE topologies require between 14 to 18 components, including 2 to 4 active devices, but their large dynamic (attenuation) range is wasted in this amplifier gain adjustment application. To create a more economical and smaller VVA for amplifier gain adjustment, we investigated a new circuit configuration comprising one active and four passive components. This paper describes …

Interconnection Of Oman And Uae Electric Power Systems, Omar H. Abdalla, Rashid Al-Badwawi, Hilal S. Al-Hadi, Hisham A. Al-Riyami, Ahmed Al-Nadabi, Karim Karoui, Ariadne Szekut

Omar H. Abdalla

Anatomy Of A Nanoscale Conduction Channel Reveals The Mechanism Of A High-Performance Memristor, Feng Miao, John Strachan, Jianhua Yang, M Zhang, Ilan Goldfarb, Antonio Torrezan, Peter Eschbach, Ronald Kelley, Gilberto Medeiros-Ribeiro, R Stanley Williams

Jianhua Yang

Response Characterization Of Electroactive Polymers As Mechanical Sensors, G. Alici, Geoffrey M. Spinks, J. D. Madden, Y. Wu, G G. Wallace

Gordon Wallace

The characterization of the dynamic response (including transfer function identification) of trilayer polypyrrole (PPy) type conducting polymer sensors is presented. The sensor was built like a cantilever beam with the free end stimulated through a mechanical lever system, which provided displacement inputs. The voltage generated and current passing between the two outer PPy layers as a result of the input was measured to model the output/input behavior of the sensors based on their experimental current/displacement and voltage/displacement frequency responses. We specifically targeted the low-frequency behavior of the sensor as it is a relatively slowsystem. Experimental transfer function models were generated …

Wide Aea Protection (Wap) Systems: Benefits, Schemes, And Examples, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

No abstract provided.

A Tutorial On Bayesian Networks For System Health Management, Arthur Choi, Lu Zheng, Adnan Darwiche, Ole J. Mengshoel

Ole J Mengshoel

Bayesian networks have established themselves as an indispensable tool in artificial intelligence, and are being used effectively by researchers and practitioners more broadly in science and engineering. The domain of system health management, including diagnosis, is no exception. In fact, diagnostic applications have driven much of the developments in Bayesian networks over the past few decades. In this chapter, we provide a gentle and accessible introduction to modeling and reasoning with Bayesian networks, with the domain of system health management in mind.

Risk-Based Critical Infrastructure Priorities For Emp And Solar Storms, George H. Baker Iii

George H Baker

Two electromagnetic phenomena have the potential to create continental-scale disasters. The first, nuclear electromagnetic pulse (EMP), results from a nuclear detonation high above the tropopause. The second, a major solar storm, or "solar tsunami" occurs naturally when an intense wave of charged particles from the sun perturbs the earth's magnetic field. Both phenomena can debilitate electrical and electronic systems necessary for the operation of infrastructure systems and services. One reason why a U.S. protection program has yet to be initiated is that policy makers continue to wrestle with the question of where to begin, given the Department of Homeland Security’s …

Issues In Human Capital Development : Lessons For Public Administration And Governance, Deogratias Harorimana Mr

Dr Deogratias Harorimana

With few minerals or other natural resources, Rwanda believes that she can still achieve her ambitions by investing in human capital - her unique resource. If this ambition can be achieved, then is this the next role model for international development? We used a case study design and analysis methods to examine development models used elsewhere in recent decades, using both qualitative and quantitative data on Rwanda to establish the comparative advantages in relation to Singapore’s economic development model. The implications for international development are that (1) an effective human capital development strategy should be inclusive enough to respond to …

Semantic Geotagging: A Location-Based Hypermedia Approach To Creating Situational Awareness, Ray Bareiss, Martin Griss, Steven Rosenberg, Yu Zhang

Ray Bareiss

As emergency first responders and commanders increasingly use mobile phones, tablets, and social media to communicate, coordinate, and manage information during disasters, we see a need and opportunity to provide a mobile device-appropriate semantic layer to a geographically-based common operating picture. The challenge is to provide a simple, usable structure for a rapidly growing body of information to simplify the development of situational awareness in an unfolding disaster. We use a hyperlinked structure based on the ASK model to organize information in a readily accessible form. In this paper we describe our initial design and experience with an Android-based prototype, …

Semantic Geotagging: A Location-Based Hypermedia Approach To Creating Situational Awareness, Ray Bareiss, Martin Griss, Steven Rosenberg, Yu Zhang

Martin L Griss

As emergency first responders and commanders increasingly use mobile phones, tablets, and social media to communicate, coordinate, and manage information during disasters, we see a need and opportunity to provide a mobile device-appropriate semantic layer to a geographically-based common operating picture. The challenge is to provide a simple, usable structure for a rapidly growing body of information to simplify the development of situational awareness in an unfolding disaster. We use a hyperlinked structure based on the ASK model to organize information in a readily accessible form. In this paper we describe our initial design and experience with an Android-based prototype, …

Aluminum Nitride Reconfigurable Rf-Mems Front-Ends, Augusto Tazzoli, Matteo Rinaldi, Chengjie Zuo, Nipun Sinha, Jan Van Der Spiegel, Gianluca Piazza

Matteo Rinaldi

Aluminum Nitride based piezoelectric microelectromechanical systems (MEMS) technology has the potential to develop a fully integrated radio frequency (RF) platform that satisfies the requirements of next-generation communication standards: reconfigurability, miniaturization, and low power consumption. Here we report on the recent developments of this AlN thin-film based technology, namely resonators, filters, oscillators and switches. These examples highlight how MEMS will enable the mass manufacturing of reconfigurable RF front-ends.

Vva Extends Bw And Dynamic Range, Chin-Leong Lim

Chin-Leong Lim

Voltage-variable attenuators (VVAs) enable gain adjustment in a wide range of applications, including in cable-television (CATV), satellite-television (SATV) systems, and even test equipment and measurement systems. The PI VVA configuration using PIN diodes is ubiquitous in CATV and SATV systems owing to its low part count, small size, constant impedance, high linearity, and multi-decade bandwidth. Presently, this class of VVAs have been under severe miniaturization pressure in order to shrink end-product size. To create the industry's smallest CATV/SATV-suitable VVA, we integrated all necessary components into a multi-chip-on-board (MCOB) package measuring 3.8 x 3.8 x 1.0 mm (14 mm square footprint). …

Bayesian Software Health Management For Aircraft Guidance, Navigation, And Control, Johann M. Schumann, Timmy Mbaya, Ole J. Mengshoel

Ole J Mengshoel

Modern aircraft — both piloted fly-by-wire commercial aircraft as well as UAVs — more and more depend on highly complex safety critical software systems with many sensors and computer-controlled actuators. Despite careful design and V&V of the software, severe incidents have happened due to malfunctioning software.

In this paper, we discuss the use of Bayesian networks to monitor the health of the on-board software and sensor system, and to perform advanced on-board diagnostic reasoning. We focus on the development of reliable and robust health models for combined software and sensor systems, with application to guidance, navigation, and control (GN&C). Our …

Integrating Probabilistic Reasoning And Statistical Quality Control Techniques For Fault Diagnosis In Hybrid Domains, Brian Ricks, Craig Harrison, Ole J. Mengshoel

Ole J Mengshoel

Pandaa: Physical Arrangement Detection Of Networked Devices Through Ambient-Sound Awareness, Zheng Sun, Aveek Purohit, Kaifei Chen, Shijia Pan, Trevor Pering, Pei Zhang

Zheng Sun

Future ubiquitous home environments can contain 10s or 100s of devices. Ubiquitous services running on these devices (i.e. localizing users, routing, security algorithms) will commonly require an accurate location of each device. In order to obtain these locations, existing techniques require either a manual survey, active sound sources, or estimation using wireless radios. These techniques, however, need additional hardware capabilities and are intrusive to the user. Non-intrusive, automatic localization of ubiquitous computing devices in the home has the potential to greatly facilitate device deployments.

This paper presents the PANDAA system, a zero-configuration spatial localization system for networked devices based on …

Pandaa: Physical Arrangement Detection Of Networked Devices Through Ambient-Sound Awareness, Zheng Sun, Aveek Purohit, Kaifei Chen, Shijia Pan, Trevor Pering, Pei Zhang

Aveek Purohit

Future ubiquitous home environments can contain 10s or 100s of devices. Ubiquitous services running on these devices (i.e. localizing users, routing, security algorithms) will commonly require an accurate location of each device. In order to obtain these locations, existing techniques require either a manual survey, active sound sources, or estimation using wireless radios. These techniques, however, need additional hardware capabilities and are intrusive to the user. Non-intrusive, automatic localization of ubiquitous computing devices in the home has the potential to greatly facilitate device deployments.

This paper presents the PANDAA system, a zero-configuration spatial localization system for networked devices based on …

Steady-State And Dynamic Performance Of Oman Transmission System With Diesel-Engine Driven Distributed Generation, Omar H. Abdalla, Rashid Al-Badwawi, Hilal Al-Hadi, Hisham Al-Riyami, Ahmed Al-Nadabi

Omar H. Abdalla

The paper presents simulation studies of installing a number of diesel-engine driven generating units at selected locations in the main transmission system of Oman. A total of 300MW generator units are proposed on a temporary basis to aid in meeting the peak demand in summer 2011. A digital model is developed to simulate the system including central power plants, transmission system, loads and the proposed Distributed Generation (DG). The model includes representation of governor and excitation systems. The simulation studies are performed by using the DIgSILENT PowerFacrory software package. The objective of the studies is to demonstrate effects of the …

Patient Safety: What Can Be Done About It?, Steven Dain

Steven L Dain

Much is said and written about patient safety. In Canada, a small group of dedicated physicians, nurses and engineers participates in the Canadian Standards Association and Standards Council of Canada Advisory Committees writing basic safety and essential performance requirements for a large range of anesthesia, respiratory care and critical care equipment. Over the past several years, in recognition of the globalization of trade and the international nature of medical device design and manufacturing, Canadian Anesthesiologists’ Society members Dr Steven Dain, Dr Karen Brown, Dr Matt Kurrek, Dr Ken LeDez, and Dr Jeremy Sloan have primarily participated in Organization for International …

Led Street Light Research Project, Donald K. Carter, Stephen Quick

Stephen Quick

The City of Pittsburgh planned to replace its existing 40,000 street lighting fixtures with LED fixtures and engaged the Remaking Cities Institute (RCI) to investigate the full range of potential benefits of a replacement program in business districts. The study team investigated the technological potentials offered by LED lighting, best management practices (BMP) in LED lighting and lessons learned from cities where LED lighting has been installed, as well as the place-making and aesthetic impact of LED lighting and associated technologies. The team also investigated issues raised by the use of LEDs as the light source and issues of replacing …

Pandaa: A Physical Arrangement Detection Technique For Networked Devices Through Ambient-Sound Awareness, Zheng Sun, Aveek Purohit, Philippe De Wagter, Irina Brinster, Chorom Hamm, Pei Zhang

Zheng Sun

This demo presents PANDAA, a zero-configuration automatic spatial localization technique for networked devices based on ambient sound sensing. We will demonstrate that after initial placement of the devices, ambient sounds, such as human speech, music, footsteps, finger snaps, hand claps, or coughs and sneezes, can be used to autonomously resolve the spatial relative arrangement of devices, such as mobile phones, using trigonometric bounds and successive approximation.

Visualizing And Understanding Large-Scale Bayesian Networks, Michele Cossalter, Ole J. Mengshoel, Ted Selker

Ole J Mengshoel

Bayesian networks are a theoretically well-founded approach to represent large multi-variate probability distributions, and have proven useful in a broad range of applications. While several software tools for visualizing and editing Bayesian networks exist, they have important weaknesses when it comes to enabling users to clearly understand and compare conditional probability tables in the context of network topology, especially in large-scale networks. This paper describes a system for improving the ability for computers to work with people to develop intelligent systems through the construction of high-performing Bayesian networks. We describe NetEx, a tool developed as a Cytoscape plugin, which allows …

Software Health Management With Bayesian Networks, Ole J. Mengshoel, Johann M. Schumann

Ole J Mengshoel

No abstract provided.

Emp: A Brief Tutorial, George H. Baker Iii

George H Baker

A nuclear detonation at altitudes from about 30 to 500 kilometers generates a strong electromagnetic pulse (EMP) that propagates to points on the ground within the line-of-sight of the burst. For bursts above 100 kilometers, electronics can be affected over continental scale areas. The EMP induces large voltages and currents in antennas and cables of electronic systems that will upset operation or damage circuit components if protection measures are not present. The article provides a brief tutorial on EMP environments, effects and protection.

High Power Electromagnetic Weapons: A Brief Tutorial, George H. Baker Iii

George H Baker

High power electromagnetic weapons, also referred to as high power radiofrequency (HPRF) weapons, are a type of directed energy weapons. The system effects of high power electromagnetic environments are well recognized by world scientific and military communities. Former CIA Director John Deutch has said that, "the electron is the ultimate precision-guided weapon." In the course of the investigation ofnuclear EMP effects on electronics during the Cold War period, it became evident that garden variety, unprotected electronics would malfunction, in some cases burn out, in the presence of electromagnetic fields in the hundreds to thousands of volts per meter. The EMP …

Integrated Software And Sensor Health Management For Small Spacecraft, Johann Schumann, Ole J. Mengshoel, Timmy Mbaya

Ole J Mengshoel

Despite their size, small spacecraft have highly complex architectures with many sensors and computer-controlled actuators. At the same time, size, weight, and budget constraints often dictate that small spacecraft are designed as single-string systems, which means that there are no or few redundant systems. Thus, all components, including software, must operate as reliably. Faults, if present, must be detected as early as possible to enable (usually limited) forms of mitigation. Telemetry bandwidth for such spacecraft is usually very limited. Therefore, fault detection and diagnosis must be performed on-board. Further restrictions include low computational power and small memory.

In this paper, …

Design, Modeling And Control Strategy Of Pv/Fc Hybrid Power System, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

This paper describes development of a general methodology of an autonomous PV/FC system composed of photovoltaic (PV), electrolyzer, hydrogen storage tank and fuel cell (FC). The aim of this paper is to determine optimum design, control strategy, economic and performance of a PV/FC hybrid power generation system without battery storage taking into account all losses in the system. The paper also presents a computer program based on Matlab software to determine optimum design, control strategy, economic and performance of an autonomous PV/FC hybrid power generation system. The computer program develops to size system components in order to match the load …

Vuv Absorption Cross Section Of Benzene, Relevance For Titan’S Atmosphere, F-J. Capalbo, Y. Bénilan, N. Fray, M. Schwell, Et. Es-Sebbar, N. Champion, T. Koskinen, R. Yelle

Dr. Et-touhami Es-sebbar

Saturn's largest satellite, Titan, is the only one in the Solar System known to have a thick N2/CH4, planet like atmosphere. The dissociation of these principal components and the recombination of the products make this atmosphere to be rich in organic compounds of high interest for astrobiology. Solar and stellar occultations observed by the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft can be used to characterize the composition of Titan’s upper atmosphere (400 – 1400 km). The results depend strongly on the knowledge of the molecular absorption cross sections of the atmospheric constituents (Ferradaz et al. 2009). This …

Lna Lowers Noise, Raises Oip3 At 3.5 Ghz, Chin-Leong Lim

Chin-Leong Lim

A 3.5 GHz LNA with good noise figure, gain and linearity performances has been designed around a low-cost, QFN2x2-packaged monolithic integrated circuit (MMIC). Incorporation of bias regulator, ESD protection and stability network at chip-level reduces the external component count to 12. The proprietary 0.25 um EPHEMT process achieves +15-dB gain in single stage and less than 1 dB noise figure at 3.5 GHz.

Belief Propagation By Message Passing In Junction Trees: Computing Each Message Faster Using Gpu Parallelization, Lu Zheng, Ole J. Mengshoel, Jike Chong

Ole J Mengshoel

Compiling Bayesian networks (BNs) to junction trees and performing belief propagation over them is among the most prominent approaches to computing posteriors in BNs. However, belief propagation over junction tree is known to be computationally intensive in the general case. Its complexity may increase dramatically with the connectivity and state space cardinality of Bayesian network nodes. In this paper, we address this computational challenge using GPU parallelization. We develop data structures and algorithms that extend existing junction tree techniques, and specifically develop a novel approach to computing each belief propagation message in parallel. We implement our approach on an NVIDIA …

Direct Measurement Of Graphene Adhesion On Silicon Surface By Intercalation Of Nanoparticles, Zong Zong, Chia-Ling Chen, Mehmet R. Dokmeci, Kai-Tak Wan

Kai-tak Wan

We report a technique to characterize adhesion of monolayered/multilayered graphene sheets on silicon wafer. Nanoparticles trapped at graphene-silicon interface act as point wedges to support axisymmetric blisters. Local adhesion strength is found by measuring the particle height and blister radius using a scanning electron microscope. Adhesion energy of the typical graphene-silicon interface is measured to be 151±28 mJ/m2. The proposed method and our measurements provide insights in fabrication and reliability of microelectromechanical/nanoelectromechanical systems.