Engineering Commons^™

Mobile Communications And Mobile Services, Keng Siau, Z. Shen

Research Collection School Of Computing and Information Systems

As wireless technologies evolve, the coming mobile revolution will bring dramatic and fundamental changes to the world. This revolution has already begun and is gaining momentum. The revolution will impact numerous facets of our daily lives and the way business is conducted. It will provide important data in real time to assist decision makers, exert great influence on communications between businesses and their customers, and transform the way we live our lives. This paper examines issues in providing services via wireless technologies, i.e. mobile services. The paper discusses the challenges facing mobile services, such as changes in business strategies, investment …

Mechanisms And Control Of Water Inflow To Wells In Gas Reservoirs With Bottom Water Drive, Miguel Armenta

LSU Doctoral Dissertations

Water inflow may cease production of gas wells, leaving a significant amount of gas in the reservoir. Conventional technologies of gas well dewatering remove water from inside the wellbore without controlling water at its source. This study addresses mechanisms of water inflow to gas wells and a new completion method to control it. In a vertical oil well, the water cone top is horizontal, but in a gas well, the gas/water interface tends to bend downwards. It could be economically possible to produce gas-water systems without water breakthrough. Non-Darcy flow effect (NDFE), vertical permeability, aquifer size, density of well perforation, …

Strength Properties Of Granular Materials, Brenda Novoa-Martinez

LSU Master's Theses

This thesis presents the results of the experimental work conducted on glass beads in order to investigate the effects of particle size, confining pressure, and surface roughness on the strength properties of the particulate media. Conventional triaxial compression tests were conducted to investigate those effects. Three different sizes of beads were tested: small (diameter = 0.75 – 1.00 mm), medium (diameter = 1.55 – 1.85 mm), and large (diameter = 3.30 – 3.60 mm). The glass beads were subjected to three different confining pressures: 25-, 100-, and 400-kPa. Smooth and etched beads were tested; the etched surface was achieved by …

An Analytical Model For Calculating Bounds On Call Blocking Probabilities In Leo Satellite Networks, A. Hali̇m Zai̇m

Turkish Journal of Electrical Engineering and Computer Sciences

We present an analytical model for calculating upper and lower bounds for call-blocking probabilities in a LEO satellite network that carries voice calls. The method is especially useful for large systems where calculation of call-blocking probabilities are too expensive. Our method calculates upper and lower bounds very easily and produces fairly accurate results.

Network Traffic Properties Of Bimodal Multicast Protocol, Öznur Özkasap, Mi̇ne Çağlar

Turkish Journal of Electrical Engineering and Computer Sciences

The popularity of large-scale distributed applications, such as videoconferencing, multimedia dissemination, electronic stock exchange and distributed cooperative work, has grown with the availability of high-speed networks and the expansion of the Internet. The key property of this type of applications is the need to distribute data among multiple participants together with an application-specific quality of service needs. This fact makes scalable multicast protocols an essential underlying communication structure. Although there exist several studies investigating the traffic characteristics of unicast communication, multicast traffic has not been examined extensively in previous studies. It is well known that the aggregate traffic properties of …

The \Mathcal{H}_\Infty Model Matching Problem With One Degree Of Freedom Static State Feedback, Murat Akin, Ati̇lla Bi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this paper is to develop a new approach for a solution of the continuous-time model matching problem by a static state feedback in the sense of \mathcal{H}_\infty optimality criterion by using Linear Matrix Inequalities (LMIs). The main contribution could briefly be described as to reformulate the model matching problem in LMI formulation, to present the solvability conditions and to give a design procedure for the one degree of freedom static state feedback control law. Finally, the results are applied to an example system.

New Approaches For On-Line Tuning Of The Linear Sliding Surface Slope In Sliding Mode Controllers, Sezai̇ Tokat, İbrahi̇m Eksi̇n, Müjde Güzelkaya

Turkish Journal of Electrical Engineering and Computer Sciences

The main objective of this study is to propose new approaches for on-line tuning of the linear sliding surface slope in sliding mode controllers. The new approaches are developed for a class of second order systems on new coordinate axes, one of which is the classical sliding surface and the other one is naturally chosen to be orthogonal to it. The control input of the sliding mode control law is then modified accordingly by applying the Lyapunov stability condition. The adjustment of the linear sliding surface slope defined in the new coordinate axes is achieved by tuning a new parameter …

Resonant Demagnetization Pwm Forward Converter, B. Bi̇lgi̇n, Işik Çadirci, R. Ergül, M. Ermi̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new approach to demagnetization process of a PWM forward converter (FC) is proposed. According to this approach, the demagnetization winding and diode of a conventional FC are removed, and an external capacitor is added in parallel with the secondary diode. This replacement changes the linear demagnetization process of a conventional FC into a resonant demagnetization process. The theoretical performance results of the proposed resonant demagnetization forward converter (RDFC) are compared with those of a conventional FC. A side by side comparison made between the two types of demagnetization strategies has shown that RDFC has some advantages …

Zero-Crossing Based Demodulation Of Minimum Shift Keying, Mi̇ne Kalkan, Feza Keresteci̇oğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Minimum shift keying (MSK) modulation has features such as constant envelope, compact spectrum and good error performance, which are all desirable in many digital applications including mobile radio. Numerous receiver structures to demodulate MSK have been suggested, such as correlation receivers, differential detectors and frequency discriminators. MSK is a form of biphase keying and can be detected by a zero-crossing based phase demodulator which gives near optimum performance. In this paper, the bit error performance of a zero-crossing based coherent MSK demodulator is theoretically investigated and a closed-form expression for the bit error rate is derived. The results indicate that …

Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In passive coherent locators (PCL) systems, noise and the precision of direction of arrival (DOA) estimation are key issues. This paper addresses the implementation of high-resolution DOA estimation methods, in particular the multiple signal classification (MUSIC) algorithm, the conventional beam forming (CBF) algorithm, and the algebraic constant modulus algorithm (ACMA). The goal is to compare the ACMA to the MUSIC and CBF algorithms for application to PCL. The results and analysis presented here support the use of constant modulus information, where available, as an important addition to DOA estimation. The ACMA offers many simple solutions to noise and separation related …

A Full Adaptive Observer For Dc Servo Motors, Ata Sevi̇nç

Turkish Journal of Electrical Engineering and Computer Sciences

An adaptive observer estimating all parameters and load torque is proposed for DC servo motors. The observer uses no direct feedback but the adaptation schemes use current and speed measurements. Both the observer and adaptations are simple to implement for real-time applications. Simulation results are satisfactory for the full adaptive observer. If the observer works in parallel with only load torque and armature resistance adaptations, the results are very good even if very low-quality sensors are used. In this simulation, only a single hall sensor is used as a rotational transducer, which produces a single pulse per revolution, and very …

New Infratechnologies In The Deregulated Power Sector, Jordan Shikoski, Vladimir Katic, Risto Rechkoski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper discusses new infratechnologies in the deregulated power sector. Most measurement and standardization techniques can be viewed as infratechnology. Infratechnologies are technical tools, including the measurement of data, test methods, and practices and technique. Standardization requirements are related to the measurement requirement. Although the system operation and market transactions concern many import aspects, they are insupportable and often complementary. This distinction between the technical and market information is important because the characteristics of information needs and the impact on economic efficiency and clean power are generally different. The present paper focuses on infratechnologies that can potentially increase the benefits …

Design Of A Tem-Cell With Increased Usable Test Area, Kresimir Malaric, Juraj Bartolic

Turkish Journal of Electrical Engineering and Computer Sciences

Transversal electromagnetic mode cells (TEM-cells) are used for electromagnetic compatibility measurements (emission and immunity), and for biomedical applications. Over the years, higher and higher frequencies are being used, which demands smaller transmission structures in order to obtain the homogeneous field distribution due to resonance. Such resonance destroys the TEM field, introducing higher order modes. The goal was to design the TEM-cell for GSM frequencies that will have a larger area with a homogeneous field used for testing, while still obtaining the characteristic impedance. Commercial TEM-cells used for frequencies of 900 MHz have only 2 cm in height available for testing, …

A New Simulator For Hvdc/Ac Systems-Part Ii, Baktiar Zangeneh, Abbas Shoulaie

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a performance comparison (the focus of numerical simulation) of traditional simulation (TCS,TSE) with an optimal step time simulator (SOST) for large HVdc systems.In SOST, a Detailed simulation of HVdc converter behavior has been modified to include the automatic selection of optimal integration steps, frequency-dependent effects of an ac system, ac system phase and magnitude dynamics of voltage (particularly weak ac systems), control assessment and temporary over-voltage consequences. SOST, via graphical interfaces,provides fast and accurate information of electromechanical and the electromagnetic-transients behavior of a large HVdc/HVac system.

Breakdown Probabilities For Thin Heterostructure Avalanche Photodiodes, Majeed M. Hayat, Ünal Sako ̆Glu, Oh-Hyun Kwon, Shuling Wang, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

The recurrence theory for the breakdown probability in avalanche photodiodes (APDs) is generalized to heterostructure APDs that may have multiple multiplication layers. The generalization addresses layer-boundary effects such as the initial energy of injected carriers as well as the layer-dependent profile of the dead space in the multiplication region. Reducing the width of the multiplication layer serves to both downshift and sharpen the breakdown probability curve as a function of the applied reverse-bias voltage. In structures where the injected carriers have an initial energy that is comparable to the ionization threshold energy, the transition from linear mode to Geiger-mode is …

Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …

Optimal Excess Noise Reduction In Thin Heterojunction Al0.6Ga0.4As-Gaas Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Shuling Wang, Joe C. Campbell, Archie L. Holmes, Yi Pan, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

It has been recently found that the initial-energy effect, which is associated with the finite initial energy of carriers entering the multiplication region of an avalanche photodiode (APD), can be tailored to reduce the excess noise well beyond the previously known limits for thin APDs. However, the control of the initial energy of injected carriers can be difficult in practice for an APD with a single multiplication layer. In this paper, the dead-space multiplication recurrence theory is used to show that the low noise characteristics associated with the initial-energy effect can be achieved by utilizing a two-layer multiplication region. As …

Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …

Kalman Filtering For Adaptive Nonuniformity Correction In Infrared Focal-Plane Arrays, Sergio N. Torres, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

A novel statistical approach is undertaken for the adaptive estimation of the gain and bias nonuniformity in infrared focal-plane array sensors from scene data. The gain and the bias of each detector are regarded as random state variables modeled by a discrete-time Gauss–Markov process. The proposed Gauss–Markov framework provides a mechanism for capturing the slow and random drift in the fixed-pattern noise as the operational conditions of the sensor vary in time. With a temporal stochastic model for each detector’s gain and bias at hand, a Kalman filter is derived that uses scene data, comprising the detector’s readout values sampled …

Rationalising The Construction Materials Purchasing Process, Louis Gunnigan, Alan V. Hore, Trevor Orr

Conference papers

This paper is concerned with the process used in locating and removing inefficiency in the construction materials purchasing process. In the first part, a case study is presented showing the build-up of costs involved in purchasing materials. Potential for substantial savings is revealed. The second part of the paper gives a status report on a rationalisation pilot project currently being undertaken by the Construction Information Technology Alliance (CITA). This project aims to show how greater effectiveness and efficiency can be applied to the administration of the construction materials purchasing process by the application of information technology already used widely in …

Fuel Consumption Modeling Of A Transport Category Aircraft: A Flight Operations Quality Assurance (Foqa) Analysis, Alan J. Stolzer

Publications

"Flight Operations Quality Assurance (FOQA)-derived data was used to develop parsimonious model(s) for fuel consumption on a Boeing 757 airplane using regression analysis. Using the model(s), it should be possible to identify outliers (specific flights) with respect to fuel consumption, which will enable the air carrier to investigate the cause of excessive fuel consumption and remedy the problem A major air carrier provided the database used for the study. Fuel flow was predicted by calibrated airspeed, gross weight, and n2 (ENG[1 or 2]n2). The models containing these three variables explained approximately 85% of the variation in fuel flow. A reporting …

Mechanisms Of Volatile Anesthetic-Induced Myocardial Protection, Lynda M. Ludwig, Judy R. Kersten, Katsuya Tanaka, Weidong Gu, John F. Ladisa, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Volatile anesthetics protect myocardium against reversible and irreversible ischemic injury. Experimental evidence from several in vitro and in vivo animal models demonstrates that volatile agents enhance the recovery of stunned myocardium and reduce the size of myocardial infarction after brief or prolonged coronary artery occlusion and reperfusion, respectively. This protective effect persists after the anesthetic has been discontinued, a phenomenon known as anesthetic-induced preconditioning (APC). Recent clinical data also demonstrates evidence of APC in patients during cardiac surgery. Thus, administration of volatile anesthetics may represent a novel therapeutic approach that reduces morbidity and mortality associated with perioperative myocardial ischemia and …

Sensitivity To Hand Path Curvature During Reaching, Kyle P. Lillis, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

People optimize reaching to make straight and smooth movements. We performed experiments characterizing human sensitivity to hand path deviations from a straight reach. Vision of the arm was blocked. Subjects either moved the hand along paths of constrained curvature, or a robot moved the relaxed limb along similar trajectories (active and passive conditions, respectively). Subjects responded after each trial whether or not they thought the movement curved convex right. In a series of three experiments, we tested the effects of modifying visual feedback of hand position to suppress curvature, isotonic muscle activation, and a distracter task on subjects ability to …

A Reflection On The Development, Activities And Deliverables Of The Construction It Alliance (Cita) In Ireland, Ken Thomas, Alan V. Hore

Conference papers

This paper reflects on the development, activities and deliverables of the Construction IT Alliance in the Republic of Ireland. This alliance was formed in 2001 with the vision of harnessing the potential of information and communication technologies in the Irish construction sector. CITA is a prime example of academia-industry-government collaboration in Ireland. A key driver in the development of CITA is the need to increase the extent of IT knowledge within the Irish construction sector. Membership of CITA includes leading architectural, engineering, surveying, management, construction, supplier, IT and academic organisations. The leading academic institutions in CITA are the Technological University …

Three-Dimensional Reconstruction Algorithm For A Reverse-Geometry Volumetric Ct System With A Large-Array Scanned Source, Taly Gilat Schmidt, Rebecca Fahrig, Norbert J. Pelc

Biomedical Engineering Faculty Research and Publications

We have proposed a CT system design to rapidly produce volumetric images with negligible cone beam artifacts. The investigated system uses a large array scanned source with a smaller array of fast detectors. The x-ray source is electronically steered across a 2D target every few milliseconds as the system rotates. The proposed reconstruction algorithm for this system is a modified 3D filtered backprojection method. The data are rebinned into 2D parallel ray projections, most of which are tilted with respect to the axis of rotation. Each projection is filtered with a 2D kernel and backprojected onto the desired image matrix. …

Report On The Third Acm/Ieee Joint Conference On Digital Libraries (Jcdl), Michael L. Nelson

Computer Science Faculty Publications

The Third ACM/IEEE Joint Conference on Digital Libraries (JCDL 2003) was held on the campus of Rice University in Houston, Texas, May 27 - 31. Regarding the merging of the ACM and IEEE conference series, in the JCDL 2002 conference report published last year in D-Lib Magazine Edie Rasmussen noted, "Perhaps by next year...no one will remember that it wasn't always so" [1]. Judging by the number of participants I met who did not know that the ACM and IEEE used to hold separate digital library conferences, Rasmussen's prediction has come to pass.

The Design And Evaluation Of A Plc-Based Model Predictive Controller For Application In Industrial Food Processes, Bryan T. Griffen

Dissertations and Theses @ UNI

Model Predictive Control (MPC) is a viable control strategy for industrial processes that display relatively large variations in the process variable, have complex process variable interactions, or display a large amount of process deadtime. The objective of using MPC in manufacturing is to reduce overall process variability, the result being an increase in process accuracy, precision and efficiency. This study focused on the implementation of model predictive control techniques on an industrial sugar cooking process. The goal was to implement a successful MPC solution directly on a programmable logic controller (PLC) rather than on a personal computer (PC). Although there …

An Air-Filter Sensor For Home-Used Air Conditioners, Cheng Y. Lin, Gary R. Crossman, Alok K. Verma

Engineering Technology Faculty Publications

This paper presents a successful senior project of instrumentation developed in a Mechanical Engineering Technology senior capstone course. Students were encouraged to approach the problem of designing an air-filter sensor and to propose an optimum and practical solution for the problem. Work includes conceptual design and analysis, implementation, tests and modifications. When an air filter is used in a home air conditioner, inhabitants often forget when to replace it until the cooling or heating capacity is obviously reduced. If the filter remains in service, the efficiency of the cooling/heating system will continue decreasing while the electricity bill will significantly increase. …

Active Learning In Distance Education, Carol Considine, Tony Dean

Engineering Technology Faculty Publications

Although there are many strategies for incorporating active learning exercises into the traditional classroom, incorporating active learning exercises in a distance education delivery format is more challenging. Active learning has been shown to enhance student performance and attitudes when used in conjunction with a traditional lecture format.¹ In order for students to be actively involved they must read, write, discuss, problem solve and engage higher-order thinking tasks such as analysis, synthesis, and evaluation.² The implementation of active learning exercises in distance education classes may help establish student rapport and enhance the feeling of community among the students in …

A Matlab-Based Upper Division Systems Analysis Course For Engineering Technology, William D. Stanley, Paul L. Kauffmann, Gary R. Crossman

Engineering Technology Faculty Publications

The Department of Engineering Technology at Old Dominion University offers TAC of ABET accredited baccalaureate programs in Civil Engineering Technology, Electrical Engineering Technology, and Mechanical Engineering Technology. All students are required to take traditional courses in algebra and trigonometry, as well as differential and integral calculus, at the freshman and sophomore levels. While these courses provided the necessary basic mathematical skills, it was difficult to justify the traditional upper-division mathematics courses such as differential equations, vector analysis, etc., as appropriate for the special needs of engineering technology students.

To address this issue, the Department has undertaken the development of a …