Engineering Commons^™

Ict For Poverty Alleviation In Pacific Island Nations: Study Of Icts4d In Fiji, Deogratias Harorimana, Opeti Rokotuinivono, Emali Sewale, Fane Salaiwai, Marica Naulu, Evangelin Roy

Dr Deogratias Harorimana

ICT for Poverty Alleviation in Pacific Island Nations: Study of ICTs4D in Fiji There has been a vague and little knowledge on the role or potential of Information and Communications Technologies (ICTs) in relation to addressing poverty in Fiji. This may be probably due to the newness of the technology in the South Pacific Region as a whole but also probably due to the fact that only 9.7% of the current Fiji 931,000 populations are internet users (ITC Figures 2011). This paper reports on finding how ICTs is contributing towards poverty alleviation in Fiji. On the basis of reviewed best …

Technical Comparison Of Harmonic Mitigation Techniques For Industrial Electrical Power Systems, Almoataz Abdelaziz

Almoataz Youssef Abdelaziz

Power system harmonics cause many problems like equipment failures, malfunctions and plant shutdowns. Accordingly, mitigation of these harmonics is considered an important target especially for the industrial applications where any short downtime period may lead to great economic losses. There are at least ten different mitigation techniques to choose from, each with specific technical advantages and disadvantages. Comparative studies for the harmonic mitigation techniques in industrial electrical systems are rarely found in the literature even though they are strongly needed. This paper, almost for the first time, provides comprehensive technical comparisons between the various practical harmonics mitigation techniques in the …

Detection Of Line Outage In Transmission Networks Using Phasor Measurement Units Aided By Support Vector Machine Algorithms, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

Many protection applications are based upon the Phasor Measurement Units (PMUs) technology. Therefore, PMUs have been increasingly widespread throughout the power network, and there are several researches have been made to locate the PMUs for complete system observability. This paper introduces an important application of PMUs in power system protection which is the detection of single line outage. In addition, a detection of the out of service line is achieved depending on the variations of phase angles measured at the system buses where the PMUs are located. Hence, a protection scheme from unexpected overloading in the network that may lead …

Protection Schemes Based On Support Vector Machine For Thyristor Controlled Series Compensated Transmission Line, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

Recently, series compensation is widely used in transmission. However, this creates several problems to conventional protection approaches. This paper presents overcurrent and distance protection schemes, for fault classification in transmission lines with thyristor controlled series capacitor (TCSC) using support vector machine (SVM). The fault classification task is divided into four separate subtasks (SVMa, SVMb, SVMc and SVMg), where the state of each phase and ground is determined by an individual SVM. The polynomial kernel SVM is designed to provide the optimal classification conditions. Wide variations of load angle, fault inception angle, fault resistance and fault location have been carried out …

Phasor Measurement Units (Pmus) Based Fault Location Of Series Compensated Transmission Lines, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

Phasor Measurement Units (PMUs) have gained a great popularity in the field of control and wide area protection during the last decade. One of the major protection applications based on PMUs technology is to determine the fault location in a transmission line. Therefore, several researches have been developed in the field of fault location. Some of the researches are based on one-end measurements. But, a greater accuracy has been achieved on the basis of two-end measurements. Many researchers suggested only voltage measurements to avoid the current transformers (CT) errors. While, others suggested methods depend on both voltages and current measurements …

Optimal Pmu Placement For Complete Observability Using Heuristic Methods, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

An essential tool for power system monitoring is state estimation. Phasor Measurement Units (PMUs) can greatly improve the state estimation process. However, for state estimation, the PMUs should be placed appropriately in the network. The problem of optimal PMU placement for full observability is analyzed in this paper. The objective of the paper is to minimize the size of the PMU configuration while allowing full observability of the network. At first, an optimal measurement set is determined to achieve full power system observability with ignoring zero injection buses. Then, the derived schemes are modified to maintain the observability after considering …

Transient Security Classification Using Gene Expression Programming Algorithm, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

No abstract provided.

Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine S. Ziemer, Nian X. Sun

Dr Guomin Yang

Strong magnetoelectric (ME) coupling was demonstrated in Fe₃O₄/PZN–PT (lead zinc niobate–lead titanate) multiferroic heterostructures obtained through a sputter deposition process. The dependence of the magnetic anisotropy on the electric field (E-field) is theoretically predicted and experimentally observed by ferromagnetic resonance spectroscopy. A large tunable in-plane magnetic anisotropy of up to 600 Oe, and tunable out-of-plane anisotropy of up to 400 Oe were observed in the Fe₃O₄/PZN–PT multiferroic heterostructures, corresponding to a large ME coefficient of 100 Oe cm/kV in plane and 68 Oe cm/kV out of plane, which match well with predicted results. In addition, the electric field manipulation of …

Tunable Miniaturized Rf Devices On Magneto-Dielectric Substrates With Enhanced Performance, Guomin Yang

Dr Guomin Yang

In this dissertation we have studied planar microstrip antennas and RF filters miniaturization and performance improvement with novel substrate, superstrate and hybrid substrate/superstrate structure. In particular, we have compared dielectric materials and magneto-dielectric materials, and used the magneto-dielectric materials to counteract the narrowing of bandwidth, and the impedance mismatch due to the use of high permittivity materials as antenna substrates. However, from materials perspective, it has been challenging to achieve self-biased magnetic materials for antenna substrate applications at frequencies>600 MHz range due to the well known Snoek limit. Magnetic thin films provide a unique opportunity for achieving self-biased magnetic …

Scaling Bayesian Network Parameter Learning With Expectation Maximization Using Mapreduce, Erik B. Reed, Ole J. Mengshoel

Ole J Mengshoel

Mapreduce For Bayesian Network Parameter Learning Using The Em Algorithm, Aniruddha Basak, Irina Brinster, Ole J. Mengshoel

Ole J Mengshoel

Recovery Time Of The Schottky-Pin Limiter, Chin-Leong Lim

Chin-Leong Lim

The Schottky-PIN limiter has a ~8dB lower limiting threshold than the self-biased PIN limiter. Following the cessation of overdrive, the limiter requires some time to return to a low-loss state. This transitory state, which is known as the recovery time or blind/dead time, disrupts communication and causes information loss. Unlike the self-biased PIN limiter, there is a dearth of information pertaining to the recovery time of the PIN-Schottky limiter. This work characterizes the most popular form of the PIN-Schottky limiter and also proposes a simple modification to speed up its recovery time. We measured recovery times of >2000uS and 130uS …

Reduce Losses In Rf Schottky-Pin Limiter Circuits, Chin-Leong Lim

Chin-Leong Lim

Limiters can protect wireless receivers from physical damage and information loss. The Schottky-PIN limiter is especially protective because its limiting threshold is ~10dB lower than that of the self-biased PIN limiter. Unfortunately, the limiter diodes have parasitic capacitances that create insertion loss. Moreover, the extra diode in the Schottky-PIN limiter increases its loss over that of the PIN diode-only limiter. Techniques to minimize 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 …

Mle+: A Tool For Integrated Design And Deployment Of Energy Efficient Building Controls, Willy Bernal, Madhur Behl, Truong Nghiem, Rahul Mangharam

Madhur Behl

We present MLE+, a tool for energy-efficient building automation design, co-simulation and analysis. The tool leverages the high-fidelity building simulation capabilities of EnergyPlus and the scientific computation and design capabilities of Matlab for controller design. MLE+ facilitates integrated building simulation and controller formulation with integrated support for system identification, control design, optimization, simulation analysis and communication between software applications and building equipment. It provides streamlined workflows, a graphical front-end, and debugging support to help control engineers eliminate design and programming errors and take informed decisions early in the design stage, leading to fewer iterations in the building automation development cycle. …

Green Scheduling For Radiant Systems In Buildings, Truong X. Nghiem, Madhur Behl, George J. Pappas, Rahul Mangharam

Madhur Behl

In this report we look at the problem of peak power reduction for buildings with electric radiant floor heating systems. Uncoordinated operation of a multi-zone radiant floor heating system can result in temporally correlated electricity demand surges or peaks in the building’s electricity consumption. As peak power prices are 200-400 times that of the nominal rate, this uncoordinated activity can result in high electricity costs and expensive system operation. We have previously presented green scheduling as an approach for reducing the aggregate peak power consumption in buildings while ensuring that indoor thermal comfort is always maintained. This report extends the …

Real-Time Heart Model For Implantable Cardiac Device Validation And Verification, Zhihao Jiang, Miroslav Pajic, Allison T. Connolly, Sanjay Dixit, Rahul Mangharam

Rahul Mangharam

Designing bug-free medical device software is difficult, especially in complex implantable devices that may be used in unanticipated contexts. Safety recalls of pacemakers and implantable cardioverter defibrillators due to firmware problems between 1990 and 2000 affected over 200,000 devices, comprising 41% of the devices recalled and are increasing in frequency. There is currently no formal methodology or open experimental platform to validate and verify the correct operation of medical device software. To this effect, a real-time Virtual Heart Model (VHM) has been developed to model the electrophysiological operation of the functioning (i.e. during normal sinus rhythm) and malfunctioning (i.e. during …

Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …

Voice Over Sensor Networks, Rahul Mangharam, Anthony Rowe, Raj Rajkumar, Ryohei Suzuki

Rahul Mangharam

Wireless sensor networks have traditionally focused on low duty-cycle applications where sensor data are reported periodically in the order of seconds or even longer. This is due to typically slow changes in physical variables, the need to keep node costs low and the goal of extending battery lifetime. However, there is a growing need to support real-time streaming of audio and/or low-rate video even in wireless sensor networks for use in emergency situations and shortterm intruder detection. In this paper, we describe a real-time voice stream-capability in wireless sensor networks and summarize our deployment experiences of voice streaming across a …

Meera: Cross-Layer Methodology For Energy Efficient Resource Allocation In Wireless Networks, Sofie Pollin, Rahul Mangharam, Bruno Bougard, Liesbet Van Der Perre, Ingrid Moerman, Ragunathan Rajkumar, Francky Catthoor

Rahul Mangharam

In many portable devices, wireless network interfaces consume upwards of 30% of scarce system energy. Reducing the transceiver’s power consumption to extend the system lifetime has therefore become a design goal. Our work is targated at this goal and is based on the following two observations. First, conventional energy management approaches have focused independently on minimizing the fixed energy cost (by shutdown) and on scalable energy costs (by leveraging, for example, the modulation, code-rate and transmission power). These two energy management approaches present a tradeoff. For example, lower modulation rates and transmission power minimize the variable energy component, but this …

Demo Abstract: Embedded Virtual Machines For Wiress Industrial Automation, Rahul Mangharam, Miroslav Pajic, Shivakumar Sastry

Rahul Mangharam

The factory of the future is the Wireless Factory - fully programmable, nimble and adaptive to planned mode changes and unplanned faults. Today automotive assembly lines loose over $22,000 per minute of downtime. The systems are rigid, difficult to maintain, operate and diagnose. Our goal is to demonstrate the initial architecture and protocols for all-wireless factory control automation. Embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology …

Optimizing Transmission And Shutdown For Energy-Efficient Packet Scheduling In Sensor Networks, Sofie Pollin, Bruno Bougard, Rahul Mangharam, Liesbet Van Der Perre, Francky Catthoor, Ragunathan Rajkumar, Ingrid Moerman

Rahul Mangharam

Energy-efficiency is imperative to enable the deployment of sensor networks with satisfactory lifetime. Conventional power management in radio communication primarily focuses independently on the physical layer, medium access control (MAC) or routing and approaches differ depending on the levels of abstraction. At the physical layer, the fundamental trade-off that exists between transmission rate and energy is exploited. This leads to the lazy scheduling approach, which consists of transmitting with the lowest power over the longest feasible duration. At MAC level, power reduction techniques tend to keep the transmission as short as possible to maximize the radio's power-off interval. Those two …

Size Matters: Size-Based Scheduling For Mpeg-4 Over Wireless Channels, Rahul Mangharam, Mustafa Demirhan, Ragunathan Rajkumar, Dipankar Raychaudhuri

Rahul Mangharam

For bursty traffic with a large peak-to-average ratio and a stochastic channel, is it possible to minimize the response time of every flow while maximizing the effective channel utilization and maintain fairness? This is the question we address in this paper. In wireless networks with a single shared channel, channel arbitration is a core issue for flows with throughput and timeliness requirements on the uplink and peer-to-peer links where the instantaneous demand is not known. This paper presents a link layer frame scheduling algorithm for delay-sensitive variable bit rate traffic, such as high-rate multimedia (MPEG-4), over a wireless channel. We …

Network Synthesis For Dynamical System Stabilization, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

Rahul Mangharam

We present our recent results in the area of distributed control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network acts as a decentralized structured controller. In this case, the network is not used only as a communication medium (as in traditional control paradigms), but instead as a fully distributed computational substrate. We show that the dynamics of the plant dictate the types of network topologies that can be used to stabilize the system. Finally, we describe how to obtain a stabilizing configuration for the WCN if the topological …

From Verification To Implementation: A Model Translation Tool And A Pacemaker Case Study, Miroslav Pajic, Zhihao Jiang, Insup Lee, Oleg Sokolsky, Rahul Mangharam

Rahul Mangharam

Model-Driven Design (MDD) of cyber-physical systems advocates for design procedures that start with formal modeling of the real-time system, followed by the model’s verification at an early stage. The verified model must then be translated to a more detailed model for simulation-based testing and finally translated into executable code in a physical implementation. As later stages build on the same core model, it is essential that models used earlier in the pipeline are valid approximations of the more detailed models developed downstream. The focus of this effort is on the design and development of a model translation tool, UPP2SF, and …

A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

Rahul Mangharam

We present a distributed scheme used for control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network itself, with no centralized node, acts as the controller. In this work, we show how the WCN can be modified to include observer style updates which substantially improves robustness of the closed-loop system to link failures. In addition, we analyze how the WCN simplifies extraction of the communication and computation schedules and enables system compositionality and scalability.

Spatio-Temporal Techniques For Anti-Jamming In Embedded Wireless Networks, Rahul Mangharam, Miroslav Pajic

Rahul Mangharam

Electromagnetic jamming results in a loss of link reliability, increased energy consumption and packet delays. In the context of energy-constrained wireless networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This coordination results in statistical and predictable activity patterns that may be easily detected and jammed. To eliminate spatio-temporal patterns of communication in the link and network layers, we present WisperNet, an energy-efficient anti-jamming protocol.WisperNet employs hardware-based time synchronization and lightweight cryptographic hashing for coordinated temporal randomization of slot schedules at the link layer and adapts routes to avoid static jammers …

The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam

Rahul Mangharam

We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. Traditional networked control schemes are designed with one of the nodes in the network acting as a dedicated controller, while the other nodes simply route information to and from the controller and the plant. We introduce the concept of a Wireless Control Network (WCN) where the entire network itself acts as the controller. Specifically, at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire …

Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …

Autoplug: An Architecture For Remote Electronic Controller Unit Diagnostics In Automotive Systems, Yash Vardhan Pant, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

In 2010, over 20.3 million vehicles were recalled. Software issues related to automotive controls such as cruise control, anti-lock braking system, traction control and stability control, account for an increasingly large percentage of the overall vehicles recalled. There is a need for new and scalable methods to evaluate automotive controls in a realistic and open setting. We have developed AutoPlug, an automotive Electronic Controller Unit (ECU) architecture between the vehicle and a Remote Diagnostics Center to diagnose, test, update and verify controls software. Within the vehicle, we evaluate observerbased runtime diagnostic schemes and introduce a framework for remote management of …

A Framework For Validation Of Implantable Medical Devices, Miroslav Pajic, Zhihao Jiang, Allison Connolly, Rahul Mangharam

Rahul Mangharam

Designing bug-free medical device software is difficult, especially in complex implantable devices used for rhythm management of the cardiac or the neurological system. There is currently no formal methodology or open experimental platform to validate the correct operation of implantable medical device software. We describe our recent work on heart modeling for the validation and verification of artificial cardiac pacemakers. As we extend this platform to more complex devices such as cardioverter-defibrillators, there are several significant challenges in the modeling of biological systems and their patient-specific response to external stimulus. Our goal over the longer term is to explore the …