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Articles 1 - 30 of 35
Full-Text Articles in Engineering
Markovian Decision Control For Traffic Signal Systems, Xiao-Hua Yu, Allen R. Stubberud
Markovian Decision Control For Traffic Signal Systems, Xiao-Hua Yu, Allen R. Stubberud
Electrical Engineering
Setting signals at intersections to minimize the queue length and vehicle delay time is a key goal in traffic management. In this paper, a new control strategy for a signalized traffic intersection is developed by applying Markovian decision control theory. Statistical analysis of simulation results with different arrival rates indicate the excellent potential of this approach.
Determination Of A Flexibility Range For Cellular Manufacturing Systems Under Product Mix Variations, Hamid Seifoddini, Manocher Djassemi
Determination Of A Flexibility Range For Cellular Manufacturing Systems Under Product Mix Variations, Hamid Seifoddini, Manocher Djassemi
Industrial Technology and Packaging
One of the underlying assumptions in cellular manufacturing is that product mix is relatively stable over time. In this paper, a procedure for the sensitivity analysis of the performance of a cellular manufacturing system with respect to changes in the product mix is presented and a flexibility range representing the capability of the system in dealing with these changes is determined using simulation modelling. The simulation results in this study show that as the changes in the product mix increase the superiority of the performance of the cellular manufacturing system to the corresponding job shop system diminishes.
Formation Of A Metastable Bcc Solid Solution And Decomposition To A C15 Laves Phase In Melt-Spun Crnb10Ti10, Katherine C. Chen, P. G. Kotula, F. Chu, Dan J. Thoma
Formation Of A Metastable Bcc Solid Solution And Decomposition To A C15 Laves Phase In Melt-Spun Crnb10Ti10, Katherine C. Chen, P. G. Kotula, F. Chu, Dan J. Thoma
Materials Engineering
A metastable, disordered bcc phase has been formed from the melt in a Cr-rich alloy of the Nb-Cr-Ti system, where large volume fractions of the Laves phase would develop under equilibrium solidification conditions. X-ray diffraction (XRD) studies and lattice constant determinations confirm that the melt-spun ribbons contain a bcc phase beyond its terminal solid solution limits. Solidification pathways are proposed based upon metastable and equilibrium phase diagrams. Microstructures have been studied using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cross-sectional TEM reveals tiny, dispersed Laves phase precipitates within the metastable bcc grains near the chill (wheel) …
A New Control Strategy For A Signalized Traffic Intersection, Allen R. Stubberud, Xiao-Hua Yu
A New Control Strategy For A Signalized Traffic Intersection, Allen R. Stubberud, Xiao-Hua Yu
Electrical Engineering
A traffic control problem can be formulated as a decision-making problem for a stochastic dynamic system. Optimal traffic signal settings at intersections can minimize the vehicle delay time or the queue length at a stop line. In this paper, a new adaptive control strategy for signalized intersections is developed and tested by simulation. The simulation results show significant improvement over the traditional fully actuated control algorithm, especially for the case of high volume traffic demand.
Seismic Response Of Asymmetric Systems: Energy-Based Approach, Rakesh K. Goel
Seismic Response Of Asymmetric Systems: Energy-Based Approach, Rakesh K. Goel
Civil and Environmental Engineering
An energy-based approach has been used to investigate the seismic behavior of code-designed asymmetric-plan systems. The systems considered in this investigation had large eccentricities in both directions, were designed for bidirectional earthquake loading, and their responses were computed with both components of ground motion acting simultaneously. The presented results demonstrate that the total input energy is about the same whether the system plan is symmetric or asymmetric. Furthermore, flexible-side elements in asymmetric- plan systems may be more vulnerable to earthquakes than the same elements in symmetric-plan systems if they are not designed to accommodate the higher hysteretic-energy demands. This observation …
Period Formulas For Moment-Resisting Frame Buildings, Rakesh K. Goel, Anil K. Chopra
Period Formulas For Moment-Resisting Frame Buildings, Rakesh K. Goel, Anil K. Chopra
Civil and Environmental Engineering
Most seismic codes specify empirical formulas to estimate the fundamental vibration period of buildings. Evaluated first in this paper are the formulas specified in present U.S. codes using the available data on the fundamental period of buildings "measured" from their motions recorded during eight California earthquakes, starting with the 1971 San Fernando earthquake and ending with the 1994 Northridge earthquake. It is shown that, although the code formulas provide periods that are generally shorter than measured periods, these formulas can be improved to provide better correlation with the measured data. Subsequently, improved formulas for estimating the fundamental periods of reinforced …
Earthquake Characteristics Of Bridges With Integral Abutments, Rakesh K. Goel
Earthquake Characteristics Of Bridges With Integral Abutments, Rakesh K. Goel
Civil and Environmental Engineering
Earthquake analysis of bridges requires that the period and damping ratio be determined for each significant mode of vibration. Data on these vibration properties, identified from motions of bridges recorded during actual earthquake events, provide the most direct means of verifying and improving the current guidelines. Thus, the aim of this investigation was to measure the vibration properties of a two-span concrete bridge from its motions recorded during actual earthquake events. These data were then used to investigate how abutment participation affected the vibration properties of bridges with integral abutments. It is shown that the vibration period elongated and the …
Accuracy Of Irrigation Efficiency Estimates, A. J. Clemmens, Charles M. Burt
Accuracy Of Irrigation Efficiency Estimates, A. J. Clemmens, Charles M. Burt
BioResource and Agricultural Engineering
Evaluation of actual irrigation system performance should rely on an accurate hydrologic water balance over the area considered. In a companion paper, water uses are categorized as consumptive or nonconsumptive, and beneficial or nonbeneficial. Real performance is based on water uses over a specified period of time, rather than observation of a single irrigation event (with associate potential, but not yet actual, consumptive and/or beneficial uses). Once the components in the water balance have been determined, it is shown that the accuracy of irrigation performance parameters can be determined from the accuracy of the components in the water balance, using …
Irrigation Performance Measures: Efficiency And Uniformity, Charles M. Burt, Albert J. Clemmens, Theodor S. Strelkoff, Kenneth H. Solomon, Ronald D. Bliesner, Leland A. Hardy, Terry A. Howell, Dean E. Eisenhauer
Irrigation Performance Measures: Efficiency And Uniformity, Charles M. Burt, Albert J. Clemmens, Theodor S. Strelkoff, Kenneth H. Solomon, Ronald D. Bliesner, Leland A. Hardy, Terry A. Howell, Dean E. Eisenhauer
BioResource and Agricultural Engineering
It is essential to standardize the definitions and approaches to quantifying various irrigation performance measures. The ASCE Task Committee on Defining Irrigation Efficiency and Uniformity provides a comprehensive examination of various performance indices such as irrigation efficiency, application efficiency, irrigation sagacity, distribution uniformity, and others. Consistency is provided among different irrigation methods and different scales. Clarification of common points of confusion is provided, and methods are proposed whereby the accuracy of numerical values of the performance indicators can be assessed. This issue has two companion papers that provide more detailed information on statistical distribution uniformity and the accuracy of irrigation …
Motion-Compensating Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod
Motion-Compensating Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod
Electrical Engineering
Motion-compensating long-term memory prediction extends the spatial displacement utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensation. The long-term memory covers the decoded frames of some seconds at encoder and decoder. We investigate the influence of memory size in our motion compensation scheme and analyze the trade-off between the bit-rates spent for motion compensated prediction and residual coding. Simulation results are obtained by integrating long-term memory prediction into an H.263 codec. PSNR improvements up to 2 dB for the Foreman sequence and 1.5 dB …
Block-Based Hybrid Video Coding Using Motion-Compensated Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod
Block-Based Hybrid Video Coding Using Motion-Compensated Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod
Electrical Engineering
Our new approach extends the spatial displacement vector utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensation. The longterm memory covers the decoded frames of some seconds at the encoder's as well as the decoder's side. This scheme is well suited in cases of repetition in the sequence, e.g. a head is rotating back into its old position, or if the camera is shaking. However, transmission of the variable time delay requires additional bit-rate which may be prohibitive when the size of the long-term …
Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Materials Engineering
No abstract provided.
Field Evaluation Of Ultrasonic Method For Assessing Well Seals, Nazli Yesiller, Craig H. Benson, Tuncer B. Edil
Field Evaluation Of Ultrasonic Method For Assessing Well Seals, Nazli Yesiller, Craig H. Benson, Tuncer B. Edil
Civil and Environmental Engineering
Field tests were conducted in three boreholes using an ultrasonic testing method to evaluate its ability to assess contact between the seal and riser (casing). The ultrasonic method is used inside the riser without disturbing the riser, seal, or formation soil. The risers were 50-mm-diameter (2-inch) Schedule 40 steel pipes that are used for ground water monitoring wells. Different types of seals were placed around the risers and defects were purposely introduced in the seals to test the ultrasonic method. The ultrasonic response changed as the neat-cement seals cured or hydration of the bentonite seals changed. When adequate moisture was …
Studying Initiation And Growth Of Shear Cracks In Reinforced Concrete Beams Using Full-Field Digital Imaging, Daniel C. Jansen, Sokhwan Choi, Surendra P. Shah
Studying Initiation And Growth Of Shear Cracks In Reinforced Concrete Beams Using Full-Field Digital Imaging, Daniel C. Jansen, Sokhwan Choi, Surendra P. Shah
Civil and Environmental Engineering
The mechanisms which lead to shear failure of longitudinally reinforced concrete beams are complex and often misunderstood. In this paper, a combination of a special closed loop test technique and machine vision are applied to tests on two reinforced concrete beams failing in shear: one made of normal strength concrete and the second of high strength concrete. To control the progression of the shear crack, a closed-loop test technique was devised and employed such that the crack propagation was stable even during the post peak. To locate the crack and to measure the crack displacements, machine vision, a nondestructive measuring …
Model Of Flexural Fatigue Damage Accumulation For Cortical Bone, L. V. Griffin, J. C. Gibeling, R. B. Martin, V. A. Gibson, S. M. Stover
Model Of Flexural Fatigue Damage Accumulation For Cortical Bone, L. V. Griffin, J. C. Gibeling, R. B. Martin, V. A. Gibson, S. M. Stover
Biomedical Engineering
Analytical models that predict modulus degradation in cortical bone subjected to uniaxial fatigue loading in tension and compression are presented. On the basis of experimental observations, damage was modeled as self-limiting for tension but not for compression. These mechanistic uniaxial damage models were then developed into a model for flexural fatigue of cortical bone based on laminated beam theory. The unknown coefficients in the uniaxial damage models were obtained by successfully fitting the resulting equations to uniaxial fatigue data from the literature on human cortical bone in tension and compression. Then, the predictions of the flexural model for the behavior …
Improved Biquad Structures Using Double-Output Transconductance Blocks For Tunable Continuous-Time Filters, Vladimir I. Prodanov, Micheal M. Green
Improved Biquad Structures Using Double-Output Transconductance Blocks For Tunable Continuous-Time Filters, Vladimir I. Prodanov, Micheal M. Green
Electrical Engineering
A family of gm −C biquad structures is derived. These biquads require only a pair of grounded capacitors and three transconductors. It is shown that a pair of complex zeros can be realized simply by replicating the output stage of the transconductance block, thereby constructing a second output current that is proportional to the original output current. Although these biquad structures are very compact, they allow independent programming of the filter’s center frequency and Q. IC simulations and measurements are presented using a fifth-order tunable filter as an example.
Drip Irrigation Technology: A Resource Management Tool For Farmers, John C. Roberts, Stuart W. Styles
Drip Irrigation Technology: A Resource Management Tool For Farmers, John C. Roberts, Stuart W. Styles
BioResource and Agricultural Engineering
No abstract provided.
Fertigation Chemicals, Charles M. Burt
Fertigation Chemicals, Charles M. Burt
BioResource and Agricultural Engineering
When deciding what chemicals to inject, there are numerous considerations to be made. This paper addresses some of the more common factors which should be considered, but which are often overlooked. Because nitrogen fertilizer is injected more widely than any other nutrient, special attention is given to it
A Model For General Periodic Excitation With Random Disturbance And Its Application, Y. K. Zhou, Z. K. Hou, M. F. Dimentberg, Mohammad N. Noori
A Model For General Periodic Excitation With Random Disturbance And Its Application, Y. K. Zhou, Z. K. Hou, M. F. Dimentberg, Mohammad N. Noori
Office of the Dean (CENG) Scholarship
Many vibration problems involve a general periodic excitation such as those of a triangular or rectangular waveform. In practice, the periodic excitation may become disordered due to uncertainties. This paper presents a stochastic model for general periodic excitations with random disturbances which is constructed by introducing random amplitude and phase disturbances to individual terms in the Fourier series of the corresponding deterministic periodic function. Mean square convergence of the random Fourier series are discussed. Monte Carlo simulation of disordered sawtooth, triangular, and quadratic wave forms are illustrated. An application of the excitation is demonstrated by vibration analysis of a single-degree-of-freedom …
Development Of A Mechatronics Design Studio, Sema E. Alptekin
Development Of A Mechatronics Design Studio, Sema E. Alptekin
Industrial and Manufacturing Engineering
Mechatronics is a combination of mechanics, electronics and information technology intended to raise the intelligence level and flexibility of products and devices. There is a need to develop programs and laboratories in Mechatronics to create an understanding of how new technologies influence the traditional methods of designing products and manufacturing systems. A model "Mechatronics Design Studio" has recently been developed to support the Mechatronics and Manufacturing Automation courses offered at Cal Poly's Industrial and Manufacturing Engineering Department. Laboratory experiments have been developed and several student projects have been completed. In this paper, an overview of the design studio and select …
Design Techniques And Paradigms Toward Design Of Low-Voltage Cmos Analog Circuits, Vladimir I. Prodanov, Michael M. Green
Design Techniques And Paradigms Toward Design Of Low-Voltage Cmos Analog Circuits, Vladimir I. Prodanov, Michael M. Green
Electrical Engineering
Techniques for the design of robust low-voltage CMOS analog circuits are given. It is shown that both Vt-independence and proper alignment between the input and output swings are crucial for effective design of low-voltage circuits.
Environmental Engineering Design, Harold M. Cota, Samuel A. Vigil
Environmental Engineering Design, Harold M. Cota, Samuel A. Vigil
Civil and Environmental Engineering
This paper outlines the capstone environmental engineering design course that has been used effectively at California Polytechnic State University. Senior level students work in teams on a multi-media industrial problem. The experience involves literature review, problem formulation, proposal writing, time management, technical and economic analysis and an oral and written presentation of the results. Feedback from alumni and employers has been positive.
Determination Of Drag From Three-Dimensional Viscous And Inviscid Flowfield Computations, David L. Hunt, Russell M. Cummings, M. B. Giles
Determination Of Drag From Three-Dimensional Viscous And Inviscid Flowfield Computations, David L. Hunt, Russell M. Cummings, M. B. Giles
Aerospace Engineering
A momentum balance approach is used to extract the drag from flowfield computations for wings and wing/bodies in subsonic/transonic flight. The drag is decomposed into vorticity, entropy, and enthalpy components which can be related to the established engineering concepts of induced drag, wave and profile drag, and engine power and efficiency. This decomposition of the drag is useful in formulating techniques for accurately evaluating drag using computational fluid dynamics calculations or experimental data. A formulation for reducing the size of the region of the crossflow plane required for calculating the drag is developed using cut-off parameters for viscosity and entropy. …
Energy Based Approach To Earthquake Response Of Asymmetric Systems, Rakesh K. Goel
Energy Based Approach To Earthquake Response Of Asymmetric Systems, Rakesh K. Goel
Civil and Environmental Engineering
No abstract provided.
Evaluation Of Code Period Formula For Concrete Mrf Buildings, Rakesh K. Goel, Anil K. Chopra
Evaluation Of Code Period Formula For Concrete Mrf Buildings, Rakesh K. Goel, Anil K. Chopra
Civil and Environmental Engineering
The empirical formula specified in US building codes for fundamental vibration period of concrete moment resisting frame buildings is evaluated using periods of buildings measured from their strong motion records. The presented results show that the current code formula may lead to fundamental periods that are much shorter than the measured periods. In order to obtain better correlation between measured and computed periods, regression analysis technique has been used. The results indicate that the value of C, in the current code formula should be increased from its present value of 0.030 to 0.035.
A Differential Active Load And Its Applications In Cmos Analog Circuit Designs, Vladimir I. Prodanov, Michael M. Green
A Differential Active Load And Its Applications In Cmos Analog Circuit Designs, Vladimir I. Prodanov, Michael M. Green
Electrical Engineering
In this paper we describe a CMOS differential active load and show how it can be used to create various useful structures. Tunable current gain stages and current squaring circuits are discussed. Their connection to a differential pairbased transconductor results in broad-range tunable transconductor structures suitable for adaptive continuous-time filtering applications and a four-quadrant voltage multiplier.
Permeability Study Of Cracked Concrete, Kejin Wang, Daniel C. Jansen, Surendra P. Shah, Alan F. Karr
Permeability Study Of Cracked Concrete, Kejin Wang, Daniel C. Jansen, Surendra P. Shah, Alan F. Karr
Civil and Environmental Engineering
Cracks in concrete generally interconnect flow paths and increase concrete permeability. The increase in concrete permeability due to the progression of cracks allows more water or aggressive chemical ions to penetrate into the concrete, facilitating deterioration. The present work studies the relationship between crack characteristics and concrete permeability. In this study, feedback controlled splitting tests are introduced to generate crack width-controlled concrete specimens. Sequential crack patterns with different crack widths are viewed under a microscope. The permeability of cracked concrete is evaluated by water permeability tests. The preliminary results indicate that crack openings generally accelerate water flow rate in concrete. …
Ultrasonic Method For Evaluation Of Annular Seals For Wells And Instrument Holes, Nazli Yesiller, Tuncer B. Edil, Craig H. Benson
Ultrasonic Method For Evaluation Of Annular Seals For Wells And Instrument Holes, Nazli Yesiller, Tuncer B. Edil, Craig H. Benson
Civil and Environmental Engineering
An ultrasonic testing method employing the pulse-echo inspection technique was developed to assess the integrity of annular seals surrounding casings (i.e., instrument tubes or well casings). This nondestructive testing method permits testing a seal from inside a casing without disturbing the casing, seal, or formation. Seals constructed with cement-based and bentonite-based sealants surrounding various types and sizes of casings can be evaluated using the method. An evaluation is conducted by sending and receiving ultrasonic waves using a single piezoelectric transducer and commercially available hardware (a pulser receiver and a waveform analyzer). A probe was designed and constructed for downhole testing. …
Residual Strength Of Equine Bone Is Not Reduced By Intense Fatigue Loading: Implications For Stress Fracture, R. B. Martin, V. A. Gibson, S. M. Stover, J. C. Gibeling, L. V. Griffin
Residual Strength Of Equine Bone Is Not Reduced By Intense Fatigue Loading: Implications For Stress Fracture, R. B. Martin, V. A. Gibson, S. M. Stover, J. C. Gibeling, L. V. Griffin
Biomedical Engineering
Fatigue or stress fractures are an important clinical problem in humans as well as racehorses. An important question in this context is, when a bone experiences. fa!igue damage ~uring e~treme use, how much is it weakened compared to its original state? Since there are very ltmtted data on thts quesuon and stress fractures are common in racehorses, we sought to determine the effect of fatigue loading on the monotonic l:trength of equine cortical bone. Beams were machined from the dorsal, medial and lateral cortices of the third metacarpal bones of six thoroughbred racehorses. Beams from left and right bones were …
Bipolar/Cmos (Weak Inversion) Rail-To-Rail Constant-G M Input Stage, Vladimir I. Prodanov, Michael M. Green
Bipolar/Cmos (Weak Inversion) Rail-To-Rail Constant-G M Input Stage, Vladimir I. Prodanov, Michael M. Green
Electrical Engineering
A rail-to-rail constant-gm input stage suitable for bipolar or weak inversion CMOS implementation is presented. To achwe rail-to rail operation, two complementary differential pairs driven in parallel are used. To guarantee constant net transconductance each differential pair is augmented with a suitable biasing circuit. The biasing circuits are implemented without current mirrors, which results in low sensitivity to process variations and potentially higher bandwidth.