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Electrical and Computer Engineering

Selected Works

2013

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Articles 181 - 195 of 195

Full-Text Articles in Engineering

A Survey Of Transmission Technologies For Planning Long Distance Bulk Transmission Overlay In Us, Venkat Krishnan, James Mccalley Dec 2012

A Survey Of Transmission Technologies For Planning Long Distance Bulk Transmission Overlay In Us, Venkat Krishnan, James Mccalley

Venkat Kumar Krishnan

No abstract provided.


Voltage Unbalance Emission Assessment In Interconnected Power Systems, Upuli Jayatunga, Sarath Perera, Philip Ciufo, Ashish P. Agalgaonkar Dec 2012

Voltage Unbalance Emission Assessment In Interconnected Power Systems, Upuli Jayatunga, Sarath Perera, Philip Ciufo, Ashish P. Agalgaonkar

Dr Philip Ciufo

The International Electrotechnical Commission (IEC) Technical Report IEC/TR 61000-3-13:2008 considers voltage unbalance (VU) emission assessment as a key aspect of the VU management of power systems. Compliance assessment of unbalanced installations at the post connection stage is essential to ensure that the limits set by the IEC VU emission allocation methodology in the pre-connection stage are met. Although, VU is known to be caused by load asymmetries and inherent network asymmetries, locating all VU emission sources is not a straightforward process, especially in a network with interconnections. Such assessment methodologies should ensure that the contributions from various sources of unbalance …


Point Of Common Coupling (Pcc) Voltage Control Of A Grid-Connected Solar Photovoltaic (Pv) System, Brian Perera, Philip Ciufo, Sarath Perera Dec 2012

Point Of Common Coupling (Pcc) Voltage Control Of A Grid-Connected Solar Photovoltaic (Pv) System, Brian Perera, Philip Ciufo, Sarath Perera

Dr Philip Ciufo

In future low voltage grids, with multiple inverter interfaced sources connected, voltage regulation may become a necessary task. The potential exists for inverter interfaced sources to be deployed to regulate the voltage at the point of common coupling (PCC) of each inverter interfaced sources. The PCC voltage regulation is attainable with inverter interfaced sources by dynamically controlling the amount of reactive power injected to the power distribution grid by individual systems. In the current research, a closed-loop controller is proposed to regulate the PCC voltage of a solar photovoltaic (PV) system that is connected to a single-phase power distribution feeder …


Analysis Of Sensor Data In Cyber-Physical System, Xianglong Kong Dec 2012

Analysis Of Sensor Data In Cyber-Physical System, Xianglong Kong

Xianglong Kong

Cyber-Physical System (CPS) become more and more importance from industrial application (e.g., aircraft control, automation management) to societal challenges (e.g. health caring, environment monitoring). It has traditionally been designed to one specific application domain and to be managed by a single entity, implemented communication between physical world and computational world. However, it still just work within its domain, and not be interoperability. How to make it into scalable? How to make it reusing? These questions become more and more necessary. In this paper, we are trying to developing a common CPS infrastructure, let it be an innovative CPS crossing multiple …


Point Of Common Coupling (Pcc) Voltage Control Of A Grid-Connected Solar Photovoltaic (Pv) System, Brian Perera, Philip Ciufo, Sarath Perera Dec 2012

Point Of Common Coupling (Pcc) Voltage Control Of A Grid-Connected Solar Photovoltaic (Pv) System, Brian Perera, Philip Ciufo, Sarath Perera

Dr Philip Ciufo

In future low voltage grids, with multiple inverter interfaced sources connected, voltage regulation may become a necessary task. The potential exists for inverter interfaced sources to be deployed to regulate the voltage at the point of common coupling (PCC) of each inverter interfaced sources. The PCC voltage regulation is attainable with inverter interfaced sources by dynamically controlling the amount of reactive power injected to the power distribution grid by individual systems. In the current research, a closed-loop controller is proposed to regulate the PCC voltage of a solar photovoltaic (PV) system that is connected to a single-phase power distribution feeder …


Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq Dec 2012

Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq

Dr. Et-touhami Es-sebbar

Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296–529 K. The VUV measurements are performed between 115 and 205 nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25 μm (∼6500–400 cm−1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A′→X1A′) around 150–205 nm …


Design And Practical Implementation Of A Simple Data Acquisition System For Photovoltaic Applications, Dr. Adel A. Elbaset Dec 2012

Design And Practical Implementation Of A Simple Data Acquisition System For Photovoltaic Applications, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

There are several commercial systems for testing PV modules under field conditions but they are expensive. This paper presents a design and implementation of a simple, low cost and high efficient data acquisition system for testing the photovoltaic modules under different operating conditions (different solar radiation levels and surface temperatures). It has been designed to be the laboratory basic element for the photovoltaic generators characterization. This data acquisition system is designed to acquire and then records the signals from the different sensors that are used for measuring the different parameters of the PV system. These measurements of the different parameter …


Connectivity Of Wireless Ad Hoc Networks: Impacts Of Antenna Models, Qiu Wang, Hong-Ning Dai, Qinglin Zhao Dec 2012

Connectivity Of Wireless Ad Hoc Networks: Impacts Of Antenna Models, Qiu Wang, Hong-Ning Dai, Qinglin Zhao

Hong-Ning Dai

This paper concerns the impact of various antenna models on the network connectivity of wireless ad hoc networks. Existing antenna models have their pros and cons in the accuracy reflecting realistic antennas and the computational complexity. We therefore propose a new directional antenna model called Approx-real to balance the accuracy against the complexity. We then run extensive simulations to compare the existing models and the Approx-real model in terms of the network connectivity. The study results show that the Approx-real model can better approximate the best accurate existing antenna models than other simplified antenna models, while introducing no high computational …


On Busy-Tone Based Mac Protocol For Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu Dec 2012

On Busy-Tone Based Mac Protocol For Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

The application of directional antennas in wireless ad hoc networks offers numerous benefits, such as the extended communication range, the increased spatial reuse, the improved capacity and the suppressed interference. However, directional antennas can cause new location-dependent carrier sensing problems, such as new hidden terminal and deafness problems, which can severely degrade the network performance. Recently, a few schemes have been proposed to address these problems. However, most of these existing methods can only partially solve the hidden terminal and deafness problems. Some of them even bring significant performance overhead. In this paper, we propose a novel MAC protocol, in …


Eavesdropping Security In Wireless Ad Hoc Networks With Directional Antennas, Qiu Wang, Hong-Ning Dai, Qinglin Zhao Dec 2012

Eavesdropping Security In Wireless Ad Hoc Networks With Directional Antennas, Qiu Wang, Hong-Ning Dai, Qinglin Zhao

Hong-Ning Dai

The eavesdropping security of wireless ad hoc networks has attracted considerable attention recently. However, most of current studies only consider OMN networks, where each node is mounted with a single omni-directional antenna, which radiates radio signals in all directions and consequently leads to the high eavesdropping possibility. Compared with an omnidirectional antenna, a directional antenna can concentrate the radio signals on some desired directions so that it can potentially reduce the eavesdropping possibility. This paper investigates the eavesdropping security of wireless ad hoc networks equipped with directional antennas. In particular, we study the eavesdropping possibility of OMN networks, SDA networks …


An Overview Of Using Directional Antennas In Wireless Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu Dec 2012

An Overview Of Using Directional Antennas In Wireless Networks, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

Compared with omni-directional antennas, directional antennas have many merits, such as lower interference, better spatial reuse, longer transmission range and the improved network capacity. Directional antennas enable numerous emerging outdoor and indoor applications, which have been addressed in many recent studies. Despite the advances in wireless networks with directional antennas (DAWNs), there are many research challenges in all layers of DAWNs. This paper presents a detailed study on recent advances and open research issues on DAWNs. Firstly, we briefly introduce the classification of directional antennas, antenna radiation patterns, antenna modes as well as the challenges in the physical layer of …


Channel Allocation In Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu Dec 2012

Channel Allocation In Wireless Networks With Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

In this paper, we study the channel allocation in multi-channel wireless ad hoc networks with directional antennas. In particular, we investigate the problem: given a set of wireless nodes equipped with directional antennas, how many channels are needed to ensure collision-free communications? We derive the upper bounds on the number of channels, which heavily depend on the node density and the interference ratio (i.e., the ratio of the interference range to the transmission range). We construct several scenarios to examine the tightness of the derived bounds. We also take the side-lobes and back-lobes as well as the signal path loss …


On Eavesdropping Attacks In Wireless Sensor Networks With Directional Antennas, Hong-Ning Dai, Qiu Wang, Dong Li, Raymond Chi-Wing Wong Dec 2012

On Eavesdropping Attacks In Wireless Sensor Networks With Directional Antennas, Hong-Ning Dai, Qiu Wang, Dong Li, Raymond Chi-Wing Wong

Hong-Ning Dai

The eavesdropping attack is a serious security threat to a wireless sensor network (WSN) since the eavesdropping attack is a prerequisite for other attacks. Conventional WSNs consist of wireless nodes equipped with omnidirectional antennas, which broadcast radio signals in all directions and are consequently prone to the eavesdropping attacks. Different from omnidirectional antennas, directional antennas radiate radio signals on desired directions and potentially reduce the possibility of the eavesdropping attacks. In this paper, we propose a model to analyze the eavesdropping probability in both single-hop WSNs and multihop WSNs with omnidirectional antennas and directional antennas. We verify the correctness of …


Neural Control Of Hypersonic Flight Vehicle Model Via Time-Scale Decomposition With Throttle Setting Constraint, Bin Xu Dec 2012

Neural Control Of Hypersonic Flight Vehicle Model Via Time-Scale Decomposition With Throttle Setting Constraint, Bin Xu

Bin Xu

Considering the use of digital computers and samplers in the control circuitry, this paper describes the controller design in discrete time for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) with Neural Network (NN). Motivated by time-scale decomposition, the states are decomposed into slow dynamics of velocity, altitude and fast dynamics of attitude angles. By command transformation, the reference command for γ − θp − q subsystem is derived from h − γ subsystem. Furthermore, to simplify the backstepping design, we propose the controller for γ − θp − q subsystem from prediction function without virtual controller. For …


Flexibility And Efficiency Of New Analytical Method For Solving Systems Of Linear And Nonlinear Differential Equations, Habibolla Latifizadeh Dec 2012

Flexibility And Efficiency Of New Analytical Method For Solving Systems Of Linear And Nonlinear Differential Equations, Habibolla Latifizadeh

H. L. Zadeh

No abstract provided.