Engineering Commons^™

Scanless Fast Handoff Technique Based On Global Path Cache For Wlans, Weetit Wanalertlak, Ben Lee, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Wireless LANs (WLANs) have been widely adopted and are more convenient as they are inter-connected as wireless campus networks and wireless mesh networks. However, timesensitive multimedia applications, which have become more popular, could suffer from long end-to-end latency in WLANs.This is due mainly to handoff delay, which in turn is caused by channel scanning. This paper proposes a technique called Global Path-Cache (GPC) that provides fast handoffs in WLANs.GPC properly captures the dynamic behavior of the network andMSs, and provides accurate next AP predictions to minimize the handoff latency. Moreover, the handoff frequencies are treated as time-series data, thus GPC …

Minimal Medium For Optimal Growth And Lipid Production Of The Microalgae Scenedesmus Dimorphus, Colin Welter, Jacob Schwenk, Bahar Kanani, John Van Blargan, Joanne M. Belovich

Chemical & Biomedical Engineering Faculty Publications

The culture of Scenedesmus dimorphus at the laboratory scale has often been in standard microalgae media, such as 3N-Basal Bold medium (3N-BB), which contains 15 different chemicals. Given the extremely tight profit margins of large-scale production of biofuel from microalgae, it is important to identify the minimally sufficient quantities of nutrients necessary to maximize lipid productivity. The individual and interactive effects of six groupings of the components of 3N-BB medium on growth rate, lipid content, and total biomass yield of S. dimorphus were determined. Trace metal and vitamin concentrations were reduced to 1/6 the level of 3N-BB medium without adversely …

On The Equivalences And Differences Of Evolutionary Algorithms, Haiping Maa, Dan Simon, Minrui Feic, Zixiang Chen

Electrical and Computer Engineering Faculty Publications

Evolutionary algorithms (EAs) are fast and robust computation methods for global optimization, and have been widely used in many real-world applications. We first conceptually discuss the equivalences of various popular EAs including genetic algorithm (GA), biogeography-based optimization (BBO), differential evolution (DE), evolution strategy (ES) and particle swarm optimization (PSO). We find that the basic versions of BBO, DE, ES and PSO are equal to the GA with global uniform recombination (GA/GUR) under certain conditions. Then we discuss their differences based on biological motivations and implementation details, and point out that their distinctions enhance the diversity of EA research and applications. …

On The Uniqueness And Sensitivity Of Indentation Testing Of Isotropic Materials, J. K. Phadikar, T. A. Bogetti, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Instrumented indentation is a popular technique to extract the material properties of small scale structures. The uniqueness and sensitivity to experimental errors determine the practical usefulness of such experiments. Here, a method to identify test techniques that minimizes sensitivity to experimental erros is in indentation experiments developed. The methods are based on considering “shape functions,” which are sets of functions that describe the force–displacement relationship obtained during the indentation test. The concept of condition number is used to investigate the relative reliability of various possible dual indentation techniques. Interestingly, it was found that many dual indentation techniques can be as …

The Spatial Distribution Of Cancer Incidence In Fars Province: A Gis-Based Analysis Of Cancer Registry Data, Ali Goli, Mahbobeh Oroei, Mehdi Jalalpour, Hossein Faramarzi, Mehrdad Askarian

Civil and Environmental Engineering Faculty Publications

Background: Cancer is a major health problem in the developing countries. Variations of its incidence rate among geographical areas are due to various contributing factors. This study was performed to assess the spatial patterns of cancer incidence in the Fars Province, based on cancer registry data and to determine geographical clusters.

Methods: In this cross sectional study, the new cases of cancer were recorded from 2001 to 2009. Crude incidence rate was estimated based on age groups and sex in the counties of the Fars Province. Age standardized incidence rates (ASR) per 100,000 was calculated in each year. …

Role Of Programmed Proteolysis During Meiosis, Vincent Matthews, G. Valentin Borner Ph.D.

Undergraduate Research Posters 2013

Meiosis is the process which forms gametes and spores for reproduction in eukaryotic cells. During the pachytene phase of meiosis I, a protein structure, called the Synaptonemal Complex (SC), forms between homologous chromosomes and creates a scaffold for genetic recombination. In yeast, the Zip1 protein is a major structural component of the SC. At restrictive temperature for meiosis, ZIP1 is required for completion of meiotic divisions. At permissive temperature ZIP1 is required for proper chromosome segregation. We observed that chemical inhibition of the proteasome, with MG132, results in arrest at prophase of meiosis I. Based on these results, we questioned …

Adaptation Of Scenedesmus Dimorphus To Brackish Water, Dustin Bowden, Joanne M. Belovich

Undergraduate Research Posters 2013

Microalgae is a promising biofuel feedstock for replacement of conventional transportation fuels. Microalgae does not require arable land for cultivation, and the biofuel production rate per acre of land is an order of magnitude greater than that needed for crop-based production methods. Though microalgae to biofuel processes are attractive, none have proven commercially successful due to the high costs of algae dewatering. Moreover, the scarcity of fresh water in many parts of the world prevents development of this process because of competition with drinking water supplies. Our lab has developed an efficient dewatering method using an inclined gravity settler. It …

Using Ultrasonic Pulse Velocity (Upv) To Predict Properties And Performance Of Pervious Concrete, Jeremy Adato, Norbert Delatte

Undergraduate Research Posters 2013

Pervious concrete is a type of porous portland cement concrete with interconnected voids. This material has been increasingly used to reduce the amount of stormwater runoff from paved areas. It has also been shown to improve the water quality near low volume and low speed pavements as well as in parking lots. Due to the low compressive strength of pervious concrete associated with the high void content, it currently is not used in highway structures except perhaps as an overlay for conventional concrete pavement. The large, open pore structure of this material allows water to pass through its structure, thereby …

Design Optimization Of An Above-Knee Prosthesis With Energy Regeneration, Taylor Barto, Holly Warner, Rick Rarick, Dan Simon

Undergraduate Research Posters 2013

Above-knee amputees who use a prosthetic leg typically have to compensate for its shortcomings with unnatural hip motions. This compensation eventually leads to adverse health issues such as arthritis. We propose an active prosthesis to improve performance. The motor in our prosthetic knee allows the patient to move his hip normally, thus reducing the possibility of ancillary health issues. To improve the efficiency of the prosthesis, we use the braking phase of the prosthesis to regenerate energy. By storing energy in a supercapacitor during braking, the prosthesis lasts longer between each charge than it would without regenerative braking. We are …

Implementation Of A Plastically Dissipated Energy Criterion For Three Dimensional Modeling Of Fatigue Crack Growth, Parag G. Nittur, Anette M. Karlsson, Leif A. Carlsson

Mechanical Engineering Faculty Publications

Fatigue crack growth is simulated using three dimensional elastic-plastic finite element analysis. The crack extension per load cycle, da/dN, as well as crack front profile changes (crack tunneling) under cyclic loading is not specified as an input but evaluated based on a condition that relates plastically dissipated energy to a critical value. Simulation of cyclic crack propagation in a middle-crack tension M(T) specimen using this implementation captures the well established, experimentally obtained crack growth rate reduction accompanying a single overload event. The analysis predicts that the single overload also affects the crack front profile, where a tunneling crack propagates with …

Reliability-Based Topology Optimization Of Trusses With Stochastic Stiffness, Mehdi Jalalpour, James K. Guest, Takeru Igusa

Civil and Environmental Engineering Faculty Publications

A new method is proposed for reliability-based topology optimization of truss structures with random geometric imperfections and material variability. Such imperfections and variability, which may result from manufacturing processes, are assumed to be small in relation to the truss dimensions and mean material properties and normally distributed. Extensive numerical evidence suggests that the trusses, when optimized in terms of a displacement-based demand metric, are characterized by randomness in the stiffness that follow the Gumbel distribution. Based on this observation, it was possible to derive analytical expressions for the structural reliability, enabling the formulation of a computationally efficient single-loop reliability-based topology …

Conical Indentation Of A Viscoelastic Sphere, J. K. Phadikar, T. A. Bogetti, V. N. Kaliakin, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Instrumented indentation is commonly used for determining mechanical properties of a range of materials, including viscoelastic materials. However, most—if not all—studies are limited to a flat substrate being indented by various shaped indenters (e.g., conical or spherical). This work investigates the possibility of extending instrumented indentation to nonflat viscoelastic substrates. In particular, conical indentation of a sphere is investigated where a semi-analytical approach based on “the method of functional equations” has been developed to obtain the force–displacement relationship. To verify the accuracy of the proposed methodology selected numerical experiments have been performed and good agreement was obtained. Since it takes …

1976 Montreal Olympics: Case Study Of Project Management Failure, Ashish Patel, Paul A. Bosela, Norbert Delatte

Civil and Environmental Engineering Faculty Publications

A successful engineering project must include its timely and economic completion. A project management failure can lead to delays and cost overruns. One example of a project that greatly exceeded its projected budget is the construction of the multiple facilities for the 1976 Olympic Games in Montreal. These included the Olympic Stadium, a velodrome for bicycle events, and the Olympic Village to house the athletes. This case study reviews the circumstances of the cost increases and the design decisions and other circumstances that led to them. The difficulties were brought on by an unrealistic schedule to complete the facilities before …

Unified Forms For Kalman And Finite Impulse Response Filtering And Smoothing, Daniel J. Simon, Yuriy S. Shmaliy

Electrical and Computer Engineering Faculty Publications

The Kalman filter and smoother are optimal state estimators under certain conditions. The Kalman filter is typically presented in a predictor/corrector format, but the Kalman smoother has never been derived in that format. We derive the Kalman smoother in a predictor/corrector format, thus providing a unified form for the Kalman filter and smoother. We also discuss unbiased finite impulse response (UFIR) filters and smoothers, which can provide a suboptimal but robust alternative to Kalman estimators. We derive two unified forms for UFIR filters and smoothers, and we derive lower and upper bounds for their estimation error covariances.

Another Look At The Collapse Of Skyline Plaza At Bailey’S Crossroads, Virginia, Jeffrey Schellhammer, Norbert Delatte, Paul A. Bosela

Civil and Environmental Engineering Faculty Publications

On March 2, 1973, the Skyline Plaza apartment building in Bailey’s Crossroads, Virginia collapsed while under construction. The Occupational Health and Safety Administration (OSHA) requested an investigation from the National Bureau of Standards [(NBS); now the National Institute of Standards and Technology (NIST)]. The NBS team concluded that the most likely cause of the collapse was a punching shear failure of the 23rd floor slab. The two factors that contributed to this were premature removal of shores below the 23rd floor slab, and the low strength of the 23rd floor concrete in the area supporting the weight of the 24th …

Time-Dependent Mechanical Response Of A Composite Pfsa Membrane, Narinder S. Khattra, Zongwen Lu, Anette M. Karlsson, Michael H. Santare, F. Colin Busby, Thomas Schmiedel

Mechanical Engineering Faculty Publications

The mechanical response of a composite fuel cell membrane, made from layers of reinforced and unreinforced PFSA material, is investigated via both experimental and numerical means. First, the time-dependent mechanical properties for the reinforced layers are measured for a range of environmental and loading conditions. A three-network, viscoelastic-plastic constitutive model is developed to characterize the mechanical response of this reinforced membrane material. This constitutive model is then used in finite element simulations of a fuel cell unit (consisting of composite membrane, electrodes, gas diffusion layer and bipolar plates) where the effect of relative humidity (RH) cycling on the stress response …

An Active Disturbance Rejection Based Approach To Vibration Suppression In Two‐Inertia Systems, Shen Zhao, Zhiqiang Gao

Electrical and Computer Engineering Faculty Publications

This study concerns the resonance problems found in motion control, typically described in a two‐inertia system model as compliance between the motor and the load. We reformulate the problem in the framework of active disturbance rejection control (ADRC), where the resonance is assumed to be unknown and treated as disturbance, estimated and mitigated. This allows the closed‐loop bandwidth to go well beyond the resonant frequency, which is quite difficult using existing methods. In addition, such level of performance is achieved with minimum complexity in the controller design and tuning: no parameter estimation or adaptive algorithm is needed, and the controller …

Robust Controller Design For An Electrostatic Micromechanical Actuator, Lili Dong, Jason Edwards

Electrical and Computer Engineering Faculty Publications

In this paper, a robust feedback controller is developed on an electrostatic micromechanical actuator to extend the travel range of it beyond pull-in limit. The actuator system is linearized at multiple operating points, and the controller is constructed based on the linearized model. Two kinds of controller designs are developed for set-point tracking of the actuator despite the presences of sensor noise and external disturbance. One of them is a regular fourth order Active Disturbance Rejection Controller (ADRC) and is able to achieve 97% of the maximum travel range. And the other one is a novel multi-loop controller with a …

In Situ Analysis Of Fatigue Crack Propagation In Polymer Foams, Elio E. Saenza, Leif A. Carlsson, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This paper presents an in situ SEM experimental study on cyclic crack propagation in closed-cell polymer foams. The microscopic failure mechanisms in precracked PVC and PES specimens of 60 and 90 kg/m³ densities were examined under low-cycle fatigue loading. In the PVC foam, crack propagation occurred incrementally by successive failure of cell boundaries in front of the crack tip. The crack occasionally jumped to cell boundaries above or below the main crack resulting in non-self similar growth. Crack propagation in the PES foam occurred incrementally by extensive plastic tearing and subsequent tensile failure of the cell edge in front …

Influenza Forecasting With Google Flu Trends, Andrea Freyer Dugas, Mehdi Jalalpour, Yulia Gel, Scott Levin, Fred Torcaso, Takeru Igusa, Richard E. Rothman

Civil and Environmental Engineering Faculty Publications

Background: We developed a practical influenza forecast model based on real-time, geographically focused, and easy to access data, designed to provide individual medical centers with advanced warning of the expected number of influenza cases, thus allowing for sufficient time to implement interventions. Secondly, we evaluated the effects of incorporating a real-time influenza surveillance system, Google Flu Trends, and meteorological and temporal information on forecast accuracy.

Methods: Forecast models designed to predict one week in advance were developed from weekly counts of confirmed influenza cases over seven seasons (2004–2011) divided into seven training and out-of-sample verification sets. Forecasting procedures …

Variations Of Biogeography-Based Optimization And Markov Analysis, Haiping Ma, Daniel J. Simon, Minrui Fei, Zhikun Xie

Electrical and Computer Engineering Faculty Publications

Biogeography-based optimization (BBO) is a new evolutionary algorithm that is inspired by biogeography. Previous work has shown that BBO is a competitive optimization algorithm, and it demonstrates good performance on various benchmark functions and real-world optimization problems. Motivated by biogeography theory and previous results, three variations of BBO migration are introduced in this paper. We refer to the original BBO algorithm as partial immigration-based BBO. The new BBO variations that we propose are called total immigration-based BBO, partial emigration-based BBO, and total emigration-based BBO. Their corresponding Markov chain models are also derived based on a previously-derived BBO Markov model. The …

Biomechanics Of Prosthetic Knee Systems : Role Of Dampening And Energy Storage Systems, Hande Argunsah Bayram

ETD Archive

One significant drawback of the commercial passive and microprocessored prosthetic devices, the inability of delivering positive energy when needed, is due to the absence of the knee flexion during stance phase. Moreover, consequences such as circumduction and disturbed gait pattern take place due to the improper energy flow at the knee and the absence of the positive energy delivery during the swing phase. Current generation powered design has solved these problems by delivering the needed energy with heavy battery demanding motors, which increase the mass of the device significantly. Hence, the gait quality of transfemoral amputees has not improved significantly …

Scalp Eeg And Tms Based Electrophysiological Study Of Brain Function Of Motor Control In Aging, Mehmed Satuk Bayram

ETD Archive

Voluntary movements of human body are controlled by the brain through corticomuscular pathways. Although neuromuscular control mechanisms of voluntary movements have been studied extensively, many remain to be learned, especially neuromuscular adaptations related to clinical conditions such as neurological disorders and aging. This research aims at a better understanding of functional connection between the brain and muscle during voluntary motor activities in aging and the extent to which this connection can be changed by training the neuromuscular system. Three research projects were conducted to achieve this aim. The analyses in the first two projects are based on comparisons of non-invasive …

Electrochemical/Electroflotation Process For Dye Wastewater Treatment, Erick Benjamin Butler

ETD Archive

The use of dyes has become very significant across various industries such as textiles, paper, and clothing. The organic chemical composition of dyes is a major concern when discharging wastewater not only into the environment, but also within wastewater treatment plants. Dye effluent consists of high chemical oxygen demand (COD) and also color, components that require treatment before discharge. As a result, federal legislation has required industries that discharge high components in wastewater to undergo treatment within the plants. Within literature, authors have considered various biological, physical, and chemical methods of treating dye wastewater. Recently, electrocoagulation/electroflotation (ECF) has been an …

An In Silico Liver: Model Of Gluconeogenesis, Elie R. Chalhoub

ETD Archive

An in silico liver was developed in attempt to represent the in vivo state of the fasted liver. It featured two conceptual models. The first one represented carbohydrate metabolism of the human liver, which included the heterogeneous nature of the liver by incorporating spatial variation of key enzyme activities. This model was able to predict the overall fluxes in tissue and the effect of high intensity exercise on the various hepatic fluxes. A second model of hepatic metabolism was developed to represent the complex interplay between gluconeogenesis, lipid metabolism, and alcohol metabolism in the fasted rat liver. Biochemical pathways are …

A Robotic Neuro-Musculoskeletal Simulator For Spine Research, Robb W. Colbrunn

ETD Archive

An influential conceptual framework advanced by Panjabi represents the living spine as a complex neuromusculoskeletal system whose biomechanical functioning is rather finely dependent upon the interactions among and between three principal subsystems: the passive musculoskeletal subsystem (osteoligamentous spine plus passive mechanical contributions of the muscles), the active musculoskeletal subsystem (muscles and tendons), and the neural and feedback subsystem (neural control centers and feedback elements such as mechanoreceptors located in the soft tissues) [1]. The interplay between subsystems readily encourages "thought experiments" of how pathologic changes in one subsystem might influence another--for example, prompting one to speculate how painful arthritic changes …

Method For Determination Of Kinematic Sensor Position And Orientation From Magnetic Resonance Images, Caglar Ozturk

ETD Archive

Concussion and mild traumatic brain injury risk remain high for young athletes participating in helmeted and non-helmeted sports. Because of the short and potential long-term effects on young athletes and early onset Alzheimer's and Parkinson's disease, there is a dire need to correlate a relationship between head impact intensity, frequency, duration and athlete brain health. To address this need, the Cleveland Clinic is developing a custom mouthguard embedded with flexible circuitry and sensors, known as the 'Intelligent Mouthguard'(IMG). To accurately quantify peak values of head impacts or concussions, orientation and position of each sensor relative to CG (Center of Gravity) …

Radial Diffusion Of Florescein Molecules (376 Da) In Canine Bone Tissue, Daniel O'Conor

ETD Archive

No abstract provided.

Lipid Production By Scenedesmus Dimorphus: Comparison Of Extraction Techniques And Effect Of Sodium Nitrate Concentration, Bahareh Kanani

ETD Archive

No abstract provided.

Application Of Sliding Mode Controller And Linear Active Disturbance Rejection Controller To A Pmsm Speed System, Yang Zhao

ETD Archive

Permanent magnet synchronous motor (PMSM) is a popular electric machine in industry for its small volume, high electromagnetic torque, high reliability and low cost. It is broadly used in automobiles and aircrafts. However, PMSM has its inherent problems of nonlinearity and coupling, which are challenges for control systems design. In addition, the external disturbances such as load variation and noises could degrade the systems performance. Both sliding mode control (SMC) and active disturbance rejection control (ADRC) are robust against disturbances. They can also compensate the nonlinearity and couplings of the PMSM. Therefore, in this thesis, we apply both SMC and …