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1997

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Adaptive Search And The Preliminary Design Of Gas Turbine Blade Cooling Systems, Rajkumar Roy Jan 1997

Adaptive Search And The Preliminary Design Of Gas Turbine Blade Cooling Systems, Rajkumar Roy

School of Engineering, Computing and Mathematics Theses

This research concerns the integration of Adaptive Search (AS) technique such as the Genetic Algorithms (GA) with knowledge based software to develop a research prototype of an Adaptive Search Manager (ASM). The developed approach allows to utilise both quantitative and qualitative information in engineering design decision making. A Fuzzy Expert System manipulates AS software within the design environment concerning the preliminary design of gas turbine blade cooling systems. Steady state cooling hole geometry models have been developed for the project in collaboration with Rolls Royce plc. The research prototype of ASM uses a hybrid of Adaptive Restricted Tournament Selection (ARTS) …

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Steiner Trees Over Generalized Checkerboards, Meta M. Voelker '97 Jan 1997

Steiner Trees Over Generalized Checkerboards, Meta M. Voelker '97

Honors Projects

To minimize the length of a planar network, we can build a Steiner minimal tree that is, a tree consisting of the original network points, as well as additional, strategically-placed (Steiner) points. Chung, Gardner and Graham [2] investigated building Steiner trees over grids of unit squares. We generalize their ideas to grids of rhombuses, and show that two near-optimal Steiner trees exist for each grid, one built from Steiner trees over rhombuses and one built from Steiner trees over isosceles triangles. Further, we conjecture that for grids with an odd number of layers, only the small angle of the rhombus …

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The Dit Examiner: The Newspaper Of The Dublin Institute Of Technology Students' Union May, 1997, Dit:Students' Union Jan 1997

The Dit Examiner: The Newspaper Of The Dublin Institute Of Technology Students' Union May, 1997, Dit:Students' Union

DIT Student Union

No abstract provided.

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Diffraction From Polarization Holographic Gratings With Surface Relief In Side-Chain Azobenzene Polyesters, Izabela Naydenova, Ludmila Nikolova, Todor Todorov, N.C.R. Holme, P.S. Ramanujam, S. Hvilsted Jan 1997

Diffraction From Polarization Holographic Gratings With Surface Relief In Side-Chain Azobenzene Polyesters, Izabela Naydenova, Ludmila Nikolova, Todor Todorov, N.C.R. Holme, P.S. Ramanujam, S. Hvilsted

Articles

We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical model is proposed to explain the experimental results, making it possible to understand the influence of the different photoinduced effects. It is shown that at low intensity the polarization properties of the diffraction at these gratings are determined by the interaction of the linear and circular photobirefringences, and at larger intensity the influence of the surface …

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Applications Of Acousto-Optic Demodulation And Decoding Techniques, Matthew Graham Hicks Jan 1997

Applications Of Acousto-Optic Demodulation And Decoding Techniques, Matthew Graham Hicks

School of Engineering, Computing and Mathematics Theses

This thesis describes the operation and performance of an acousto-optic demodulator system consisting of a laser source, an acousto-optic cell and a bi-cell detector. The bi-cell detector is made up of two photodiodes positioned side by side, separated by a small gap. Theory is developed to predict the following; the linear operating range for different gap sizes, absolute frequency sensitivity, system output in response to discrete phase changes, optimum gap size for phase demodulation, absolute descrete phase change sensitivity, the performance of the system in the presence of carrier noise and the effect of clipping the carrier signal on both …

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A Geometric Approach To Modelling Interacting Populations, Jennifer M. Sharp Jan 1997

A Geometric Approach To Modelling Interacting Populations, Jennifer M. Sharp

School of Engineering, Computing and Mathematics Theses

The purpose of this thesis is to present a different approach to the formulation of differential equation mathematical models for interacting populations. It does this through considering a geometric method. The solution to the differential equations are forced, through theuformulation, to lie on the surface of well known three-dimensional shapes. It is this that allows detailed analysis of how, and why, the solution of the equations behave as they do. The thesis firstly reviews some of the skills and techniques used in the formulation and alysis of differential equation models to give a background for some of the analysis used …

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Design With Attitude: A Key World Class Method, Aj Robotham, Gn Blount Jan 1997

Design With Attitude: A Key World Class Method, Aj Robotham, Gn Blount

School of Engineering, Computing and Mathematics

World Class Design by implication can best be achieved by adopting world class methods. ICED conferences continue to disseminate methodologies to help make designers and design teams more effective and efficient. At ICED 95 we introduced our PAKTS model (Figure 1.) which identified the total educational needs of young engineering designers [Robotham 1995]. The five key elements of the model are Processes, Attitudes, Knowledge, Tools and Skills. Of these elements, the least developed in terms of methodologies is that of “Attitude”. This paper will give further consideration to this element and identify the qualities that a designer must develop to …

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Feedforward Artificial Neural Network Design Utilising Subthreshold Mode Cmos Devices, Dominique Xavier Henri Leon Coue Jan 1997

Feedforward Artificial Neural Network Design Utilising Subthreshold Mode Cmos Devices, Dominique Xavier Henri Leon Coue

School of Engineering, Computing and Mathematics Theses

This thesis reviews various previously reported techniques for simulating artificial neural networks and investigates the design of fully-connected feedforward networks based on MOS transistors operating in the subthreshold mode of conduction as they are suitable for performing compact, low power, implantable pattern recognition systems. The principal objective is to demonstrate that the transfer characteristic of the devices can be fully exploited to design basic processing modules which overcome the linearity range, weight resolution, processing speed, noise and mismatch of components problems associated with weak inversion conduction, and so be used to implement networks which can be trained to perform practical …

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Random Effect Models For Repairable System Reliability, John Nicholas Baker Jan 1997

Random Effect Models For Repairable System Reliability, John Nicholas Baker

School of Engineering, Computing and Mathematics Theses

The practical motivation for the work described in this thesis arose from the development of a new Jaguar car engine. Development tests on prototype engines led to multiple failure time data which are modelled as a non-homogeneous Poisson process in its log-linear form. Initial analysis of the data using failure time plots showed considerable differences between prototype engines and suggested the use of models incorporating random effects for the engine effects. These models were fitted using the method of maximum likelihood. Two random effects have been considered: a proportional effect and a time dependent effect. In each case a simulation …

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System Identification Theory Approach To Cohesive Sediment Transport Modelling, Huixin Chen Jan 1997

System Identification Theory Approach To Cohesive Sediment Transport Modelling, Huixin Chen

School of Engineering, Computing and Mathematics Theses

Two aspects of the modelling sediment transport are investigated. One is the univariate time series modelling the current velocity dynamics. The other is the multivariate time series modelling the suspended sediment concentration dynamics. Cohesive sediment dynamics and numerical sediment transport model are reviewed and investigated. The system identification theory and time series analysis method are developed and applied to set up the time series model for current velocity and suspended sediment dynamics. In this thesis, the cohesive sediment dynamics is considered as an unknown stochastic system to be identified. The study includes the model structure determination, system order estimation and …

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Improved Heterogeneous Distance Functions, Tony R. Martinez, D. Randall Wilson Jan 1997

Improved Heterogeneous Distance Functions, Tony R. Martinez, D. Randall Wilson

Faculty Publications

Instance-based learning techniques typically handle continuous and linear input values well, but often do not handle nominal input attributes appropriately. The Value Difference Metric (VDM) was designed to find reasonable distance values between nominal attribute values, but it largely ignores continuous attributes, requiring discretization to map continuous values into nominal values. This paper proposes three new heterogeneous distance functions, called the Heterogeneous Value Difference Metric (HVDM), the Interpolated Value Difference Metric (IVDM), and the Windowed Value Difference Metric (WVDM). These new distance functions are designed to handle applications with nominal attributes, continuous attributes, or both. In experiments on 48 applications …

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Role Of Calcium And Other Cations On Contractile Vacuole Activity Of Tetrahymena Thermophila, Robert William Bird Jan 1997

Role Of Calcium And Other Cations On Contractile Vacuole Activity Of Tetrahymena Thermophila, Robert William Bird

Dissertations and Theses @ UNI

The contractile vacuole (CV) of Tetrahymena removes fluids from the cell and maintains cellular integrity. Although many studies have been done, it is not fully understood what controls its function. Therefore, this study sought to further elucidate an understanding of what controls the activity of the CV. The effect of calcium on CV activity was studied. Twenty-four hour cultures of Tetrahymena were centrifuged, washed in an experimental solution and isolated. Single cells were measured and analyzed using computer video imaging and analysis programs. Compared to control cells, cells treated with calcium have statistically significant differences (P < 0.00001) in the following parameters: smaller overall cell volume, CV volume, and the interval between contractions. Calcium has an effect on CV activity. Increases in calcium result in decreases in cell volume and CV volume. Cadmium treated cells differed (P < 0.00001) from control cells in cell volume, CV volume, kinetics (slope) of contraction, and the interval between contractions. Increases in cadmium, relative to calcium, result in increased cell and CV volumes. Taken together, these results indicate that the control of CV activity in Tetrahymena is through stretch-activated ion selective calcium channels.

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Preservice Teachers’ Use Of Curriculum-Based Measurement In An Informal Assessment Based Reading Clinic, Tina M. Schroeder Jan 1997

Preservice Teachers’ Use Of Curriculum-Based Measurement In An Informal Assessment Based Reading Clinic, Tina M. Schroeder

Dissertations and Theses @ UNI

This study investigated 13 preservice regular education reading teachers' use of curriculum-based measurement (CBM) data under specified conditions. Conditions included: (a) providing preservice teachers with 75 minutes of training in the use of CBM in reading, (b) biweekly CBM administration and graphing during a 10-week practicum experience, and (c) concomitant use of other reading measures [e. g., Reading Miscue Inventory (RMI), Running Records (RR)]. Exit interviews indicated that preservice teachers made use of CBM data in some, but not all, of the important ways suggested in the research literature. Preservice teachers provided the following positive ratings of CBM: (a) CBM …

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Field Dependence-Independence And Sports With A Preponderance Of Closed Or Open Skills, Wenhao Liu Jan 1997

Field Dependence-Independence And Sports With A Preponderance Of Closed Or Open Skills, Wenhao Liu

Dissertations and Theses @ UNI

The focus of much research on field dependence-independence in sport settings has been on the relationship of field dependence-independence to sports with a preponderance of closed or open skills since 1970s. Although most of the previous research supported the claim that field dependence is of greater advantage to sports with a preponderance of open skills and field independence an advantage to sports with a preponderance of closed skills, several studies provided inconsistent and contradictory results. In addition, few of those studies involved adequate sports and sample size and some used a different sport classification. Little comparison, if any, of field …

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An Examination Of Environmental Sensitivity Among Supporters Of An Outdoor Recreation Area, Rodney James Blackman Jan 1997

An Examination Of Environmental Sensitivity Among Supporters Of An Outdoor Recreation Area, Rodney James Blackman

Dissertations and Theses @ UNI

The environment as an issue has been prominently before the public for over three decades. Yet the question of how much people know about the natural environment and how committed they are to the environment has seldom been considered in research literature. Research of this nature is needed because without it individuals interested in the preservation and conservation of the environment cannot be sure how their efforts to increase people's environmental sensitivity should be applied. The purpose of this study was to examine the level and extent of environmental sensitivity among supporters of an outdoor recreation area/facility in northeast Iowa. …

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Development Of A Tire Pyrolysis Process And Apparatus Using Steam Displacement Of The Combustible Atmosphere, Timothy Whitney Burrell Jan 1997

Development Of A Tire Pyrolysis Process And Apparatus Using Steam Displacement Of The Combustible Atmosphere, Timothy Whitney Burrell

Dissertations and Theses @ UNI

It is the purpose of this research to convert a batch vacuum pyrolysis process into a pyrolytic process that operates at ambient air pressure with the capabilities of a continuous material flow operation. Further, it is important to optimize the conditions of the pyrolysis process so as to reduce costs of operation and to reasonably maximize products that have value. Steam will be used to displace the combustible atmosphere which enables ambient air pressure operation and elimination of need for inert carrier gasses or evacuation of the apparatus. The use of steam also allows water traps to be used as …

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Numerical Simulations Of Full- Scale Corroded Pipe Tests With Combined Loading, Samit Roy, S. Grigory, M. Smith, M. F. Kanninen, M. Anderson Jan 1997

Numerical Simulations Of Full- Scale Corroded Pipe Tests With Combined Loading, Samit Roy, S. Grigory, M. Smith, M. F. Kanninen, M. Anderson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The ANSI/ASME B31G guideline has been useful to pipeline operators in assessing the integrity of corroded line pipe. Because large safety margins have had to be incorporated, the guidelines can be excessively conservative, which in turn can force costly repairs and replacements that may not actually be necessary. On the other hand, because the current guidelines consider only pressure loading and neglect bending and axial compression, they could give nonconservative failure predictions when combined loading exists. Therefore, a study was initiated to develop a theoretically sound methodology for assessing the integrity of corroded line pipe subjected to combined loading. A …

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Integrating Design Into The Sophomore And Junior Level Mechanics Courses, Douglas R. Carroll Jan 1997

Integrating Design Into The Sophomore And Junior Level Mechanics Courses, Douglas R. Carroll

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Engineering schools across the country are developing ways of integrating design into their curriculum, and a question that often arises is how to best integrate design into the sophomore and junior level courses. Freshman design projects or mechanical dissection courses are designed to give the students hands-on experience in conceptual design and construction, with little if any of the mathematical modeling normally used in engineering design. The capstone senior design project is a true engineering design experience, where students draw from their background to conceptualize, analyze, model, refine, and optimize a product to meet design, manufacturing, and life cycle cost …

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Eigenvalue And Eigenvector Determination For Damped Gyroscopic Systems, D. P. Malone, Don L. Cronin, Timothy W. Randolph Jan 1997

Eigenvalue And Eigenvector Determination For Damped Gyroscopic Systems, D. P. Malone, Don L. Cronin, Timothy W. Randolph

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

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Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas Jan 1997

Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A new method is presented for the measurement of the mean lepton lifetime using events in which are pair-produced and both's decay to hadrons.

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Production Of Orbitally Excited Charm Mesons In Semileptonic B Decays, D. Buskulic, M. Thulasidas Jan 1997

Production Of Orbitally Excited Charm Mesons In Semileptonic B Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

A sample of 3.6 million hadronic Z decays recorded between 1991 and 1995 with the ALEPH detector at LEP is used to investigate semileptonic decays of B mesons into final states involving orbitally excited charm mesons. Topological vertex criteria are used to search for decays involving narrow D** states as well as wide D** resonances and non-resonant D(*)π final states. The sum of the branching ratios for these processes is measured to be ${⤪ Br}({⩈erline {⤪ B}}⌝ghtarrow {⤪ D}≪ ⫑l^{-}{⩈erline v}) + {⤪ Br}({⩈erline {⤪ B}}⌝ghtarrow {⤪ D}^{⇒t}≪ ⫑l^{-}{⩈erline v})↦op =(2.26 pm 0.29({⤪ stat}) pm 0.33({⤪ syst}))%,$which accounts for a …

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Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas Jan 1997

Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The time dependence of B0 d {B 0 d oscillations is measured by the ALEPH experiment at LEP, using three techniques, two of which are updates of previous measurements. In all cases the charge of the decaying b quark and its decay time are measured in one hemisphere of the event; the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a D and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the …

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Droplet Concentration And Size Distribution In Haze And Fog, Josef Podzimek Jan 1997

Droplet Concentration And Size Distribution In Haze And Fog, Josef Podzimek

Physics Faculty Research & Creative Works

Fog (haze) droplet concentrations and size distributions were measured at five sampling sites representing rural and urban regions and a highly polluted marine-urban environment. Droplet imprints in a thin gelatine layer were evaluated and compared to the measurement by light scattering instruments. This enabled conditions for the application of the logarithmic-normal size distribution and for the classification of typical fog droplet size distributions to be established. In particular, the parameters featuring the width and asymmetry of a size distribution were suggested and calculated. Advantages and drawbacks of the applied droplet sampling and evaluation technique are discussed in more detail. © …

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Velocity Space "Snapshots" Of Continuum Electrons Produced By Slow, Bare, Highly Charged Ions: Saddle-Point Electrons?, M. Abdallah, S. Kravis, C. L. Cocke, Y. D. Wang, M. Stöckli, Ronald E. Olson Jan 1997

Velocity Space "Snapshots" Of Continuum Electrons Produced By Slow, Bare, Highly Charged Ions: Saddle-Point Electrons?, M. Abdallah, S. Kravis, C. L. Cocke, Y. D. Wang, M. Stöckli, Ronald E. Olson

Physics Faculty Research & Creative Works

Comprehensive velocity-space "snapshots" of the electron continua produced by the impact of ions on He at a projectile velocity of 1.63 a.u. have been measured for the bare projectiles of p, He, C, O and Ne. For the three highly charged ions, this velocity lies in the "ionization threshold" region where electron capture dominates the reaction. The experimental technique projects the distribution of soft continuum electrons onto a two-dimensional detector in such a way that the velocity-space distribution for all electrons with laboratory energies in the range from 0-30eV is accurately imaged. The data show no evidence for a saddle-point …

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Curriculum Development And Evaluation For A Computer Literacy Course, Molly J. Fagan Jan 1997

Curriculum Development And Evaluation For A Computer Literacy Course, Molly J. Fagan

Dissertations and Theses @ UNI

This paper describes a curriculum that was developed and used for a computer literacy course at the University of Northern Iowa. The curriculum included a unit of computer programming, which has not been included as part of the computer literacy course in recent years at the University of Northern Iowa. Surveys were given at the beginning of the semester to determine the approximate level of students' prior knowledge. The same survey was given at the end of the semester and the results of both were compared to see how much more comfortable each individual student felt using the various computer …

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An Object-Based Evolutionary Algorithm For Solving Rectangular Piece Nesting Problems, Kanchitpol Ratanapan, Cihan H. Dagli Jan 1997

An Object-Based Evolutionary Algorithm For Solving Rectangular Piece Nesting Problems, Kanchitpol Ratanapan, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Nesting problems have been tackled by researchers using a vast number of algorithms in the past. Most of the algorithms, however, need to perform on a one-dimensional space. Therefore, the problem must be transformed into a one-dimensional space problem similar to the travelling salesman problem. Consequently, loss of solutions due to the dimensional reduction may occur. In this study, an object-based evolutionary algorithm for rectangular piece nesting problems is proposed. This methodology is created on truly two-dimensional space, allowing new mechanisms (i.e., individual representation, initialization, etc.) and new object-based genetic operators (i.e., hill-climbing, mutation, and recombination operators) to perform effectively …

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High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin Jan 1997

High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin

Computer Science Faculty Research & Creative Works

The integration of object oriented modeling and structured analysis (SA) for developing a well structured object oriented software system is a challenge for requirements analysts and software designers. Some of the existing object oriented modeling techniques adopt approaches that are very different from SA, and others have clumsily stayed with SA after a few modifications. Our High Order Object Modeling Technique (HOOMT) however, attempts to strike a mean between both extremes while at the same time provides an effective modeling method. HOOMT consists of two models, the High Order Object Model and the Object Information Flow Model. By using the …

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Rmesh Algorithms For Parallel String Matching, Hsi-Chieh Lee, Fikret Erçal Jan 1997

Rmesh Algorithms For Parallel String Matching, Hsi-Chieh Lee, Fikret Erçal

Computer Science Faculty Research & Creative Works

String matching problem received much attention over the years due to its importance in various applications such as text/file comparison, DNA sequencing, search engines, and spelling correction. Especially with the introduction of search engines dealing with tremendous amount of textual information presented on the world wide web and the research on DNA sequencing, this problem deserves special attention and any algorithmic or hardware improvements to speed up the process will benefit these important applications. In this paper, we present three algorithms for string matching on reconfigurable mesh architectures. Given a text T of length n and a pattern P of …

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Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria Jan 1997

Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

We present a timestamp based algorithm for the detection of both write-write and read-write conflicts for a single file in distributed systems during network partitions. Our algorithm allows operations to occur in different network partitions simultaneously. When the sites from different partitions merge, the algorithm detects and resolves both read-write and write-write conflicts without taking into account the semantics of the transactions. Once the conflicts have been detected some reconciliation steps for the resolution of conflicts have also been proposed. Our algorithm will be useful in real-time systems where timeliness of operations is more important than response time (delayed commit)

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Short-Term Resource Scheduling With Ramp Constraints [Power Generation Scheduling], Chung-Li Tseng, Chao-An Li, A. J. Svoboda, R. B. Johnson Jan 1997

Short-Term Resource Scheduling With Ramp Constraints [Power Generation Scheduling], Chung-Li Tseng, Chao-An Li, A. J. Svoboda, R. B. Johnson

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper describes a Lagrangian relaxation-based method to solve the short-term resource scheduling (STRS) problem with ramp constraints. Instead of discretizing the generation levels, the ramp rate constraints are relaxed with the system demand constraints using Lagrange multipliers. Three kinds of ramp constraints, startup, operating and shutdown ramp constraints are considered. The proposed method has been applied to solve the hydro-thermal generation scheduling problem at PG&E. An example alone with numerical results is also presented

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