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Performance based diagnostics of a twin shaft aeroderivative gas turbine: water wash schedulingBaudin Lastra, Tomas 05 1900 (has links)
Aeroderivative gas turbines are used all over the world for different applications
as Combined Heat and Power (CHP), Oil and Gas, ship propulsion and others.
They combine flexibility with high efficiencies, low weight and small footprint,
making them attractive where power density is paramount as off shore Oil and
Gas or ship propulsion. In Western Europe they are widely used in CHP small
and medium applications thanks to their maintainability and efficiency. Reliability,
Availability and Performance are key parameters when considering plant
operation and maintenance. The accurate diagnose of Performance is
fundamental for the plant economics and maintenance planning. There has been
a lot of work around units like the LM2500® , a gas generator with an
aerodynamically coupled gas turbine, but nothing has been found by the author
for the LM6000® .
Water wash, both on line or off line, is an important maintenance practice
impacting Reliability, Availability and Performance. This Thesis aims to select and
apply a suitable diagnostic technique to help establishing the schedule for off line
water wash on a specific model of this engine type. After a revision of Diagnostic
Methods Artificial Neural Network (ANN) has been chosen as diagnostic tool.
There was no WebEngine model available of the unit under study so the first step
of setting the tool has been creating it. The last step has been testing of ANN as
a suitable diagnostic tool. Several have been configured, trained and tested and
one has been chosen based on its slightly better response. Finally, conclusions
are discussed and recommendations for further work laid out.
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A Novel Method for Water irrigation System for paddy fields using ANNPrisilla, L., Rooban, P. Simon Vasantha, Arockiam, L. 01 April 2012 (has links)
In our country farmers have to face many difficulties
because of the poor irrigation system. During flood
situation, excessive waters will be staged in paddy field
producing great loss and pain to farmers. So, proper
Irrigation mechanism is an essential component of paddy
production. Poor irrigation methods and crop management
are rapidly depleting the country’s water table. Most small
hold farmers cannot afford new wells or lawns and they are
looking for alternative methods to reduce their water
consumption. So proper irrigation mechanism not only leads
to high crop production but also pave a way for water saving
techniques. Automation of irrigation system has the
potential to provide maximum water usage efficiency by
monitoring soil moistures. The control unit based on
Artificial Neural Network is the pivotal block of entire
irrigation system. Using this control unit certain factors like
temperature, kind of the soil and crops, air humidity,
radiation in the ground were estimated and this will help to
control the flow of water to acquire optimized results. / Water is an essential resource in the earth. It is also essential for
irrigation, so irrigation technique is essential for agriculture. To
irrigate large area of lands is a tedious process. In our country
farmers are not following proper irrigation techniques. Currently,
most of the irrigation scheduling systems and their corresponding
automated tools are in fixed rate. Variable rate irrigation is very
essential not only for the improvement of irrigation system but also
to save water resource for future purpose. Most of the irrigation
controllers are ON/OFF Model. These controllers cannot give
optimal results for varying time delays and system parameters.
Artificial Neural Network (ANN) based intelligent control system
is used for effective irrigation scheduling in paddy fields. The
input parameters like air, temperature, soil moisture, radiations and
humidity are modeled. Using appropriate method, ecological
conditions, Evapotranspiration, various growing stages of crops are
considered and based on that the amount of water required for
irrigation is estimated. Using this existing ANN based intelligent
control system, the water saving procedure in paddy field can be
achieved. This model will lead to avoid flood in paddy field during
the rainy seasons and save that water for future purposes.
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Forecasting Water Main Failures in the City of Kingston Using Artificial Neural NetworksNishiyama, Michael 22 October 2013 (has links)
Water distribution utilities are responsible for supplying both clean and safe drinking water, while under constraints of operating at an efficient and acceptable performance level. The City of Kingston, Ontario is currently experiencing elevated costs to repair its aging buried water main assets. Utilities Kingston is opting for a more efficient and practical means of forecasting pipe breaks and the application of a predictive water main break models allows Utilities Kingston to forecast future pipe failures and plan accordingly.
The objective of this thesis is to develop an artificial neural network (ANN) model to forecast pipe breaks in the Kingston water distribution network. Data supplied by Utilities Kingston was used to develop the predictive ANN water main break model incorporating multiple variables including pipe age, diameter, length, and surrounding soil type. The constructed ANN model from historical break data was utilized to forecast pipe breaks for 1-year, 2-year, and 5-year planning periods. Simulated results were evaluated by statistical performance metrics, proving the overall model to be adequate for testing and forecasting. Predicted breaks were as follows, 33 breaks for 2011-2012, 22 breaks for 2012-2013 and 35 breaks for 2013-2016. Additionally, GIS plots were developed to highlight areas in need of potential rehabilitation for the distribution system. The goal of the model is to provide a practical means to assist in the management and development of Kingston’s pipe rehabilitation program, and to enable Utilities Kingston to reduce water main repair costs and to improve water quality at the customer's tap. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-10-21 15:30:10.288
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Real time evolutionary algorithms in robotic neural control systemsJagadeesan, Ananda Prasanna January 2006 (has links)
This thesis describes the use of a Real-Time Evolutionary Algorithm (RTEA) to optimise an Artificial Neural Network (ANN) on-line (in this context “on-line” means while it is in use). Traditionally, Evolutionary Algorithms (Genetic Algorithms, Evolutionary Strategies and Evolutionary Programming) have been used to train networks before use - that is “off-line,” as have other learning systems like Back-Propagation and Simulated Annealing. However, this means that the network cannot react to new situations (which were not in its original training set). The system outlined here uses a Simulated Legged Robot as a test-bed and allows it to adapt to a changing Fitness function. An example of this in reality would be a robot walking from a solid surface onto an unknown surface (which might be, for example, rock or sand) while optimising its controlling network in real-time, to adjust its locomotive gait, accordingly. The project initially developed a Central Pattern Generator (CPG) for a Bipedal Robot and used this to explore the basic characteristics of RTEA. The system was then developed to operate on a Quadruped Robot and a test regime set up which provided thousands of real-environment like situations to test the RTEA’s ability to control the robot. The programming for the system was done using Borland C++ Builder and no commercial simulation software was used. Through this means, the Evolutionary Operators of the RTEA were examined and their real-time performance evaluated. The results demonstrate that a RTEA can be used successfully to optimise an ANN in real-time. They also show the importance of Neural Functionality and Network Topology in such systems and new models of both neurons and networks were developed as part of the project. Finally, recommendations for a working system are given and other applications reviewed.
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A computationally intelligent approach to the detection of wormhole attacks in wireless sensor networksShaon, Mohammad 29 July 2016 (has links)
This thesis proposes an innovative wormhole detection scheme to detect wormhole attacks using computational intelligence and an artificial neural network (ANN). The aim of the proposed research is to develop a detection scheme that can detect wormhole attacks (In-band, out of band, hidden wormhole attack, active wormhole attack) in both uniformly and non-uniformly distributed sensor networks. Furthermore, the proposed research does not require any special hardware and causes no significant network overhead throughout the network. Most importantly, the probable location of the wormhole nodes can be tracked down by the proposed ANN-based detection scheme.
We evaluate the efficacy of the proposed detection scheme in terms of detection accuracy, false positive rate, and false negative rate. The performance of the proposed model is also compared with other machine learning techniques (i.e. SVM and regularized nonlinear logistic regression (LR) based detection models) based detection schemes. The simulation results show that proposed ANN-based detection model outperforms the SVM and LR based detection schemes in terms of detection accuracy, false positive rate, and false negative rates. / February 2017
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Predicting the unpredictable - Can Artificial Neural Network replace ARIMA for prediction of the Swedish Stock Market (OMXS30)?Ferreira de Melo Filho, Alberto January 2019 (has links)
During several decades the stock market has been an area of interest forresearchers due to its complexity, noise, uncertainty and nonlinearity of thedata. Most of the studies regarding this area use a classical stochastics method,an example of this is ARIMA which is a standard approach for time seriesprediction. There is however another method for prediction of the stock marketthat is gaining traction in the recent years; Artificial Neural Network (ANN).This method has mostly been used in research on the American and Asian stockmarkets so far. Therefore, the purpose of this essay was to explore if ArtificialNeural Network could be used instead of ARIMA to predict the Swedish stockmarket (OMXS30). The study used data from the Swedish Stock Marketbetween 1991-07-09 to 2018-12-28 for the training of the ARIMA model anda forecast data that ranged between 2019-01-02 to 2019-04-26. The forecastdata of the ANN was composed of 80% of the data between 1991-07-09 to2019-04-26 and the evaluation data was composed of the remaining 20%. TheANN architecture had one input layer with chunks of 20 consecutive days asinput, followed by three Long Short-Term Memory (LSTM) hidden layers with128 neurons in each layer, followed by another hidden layer with RectifiedLinear Unit (ReLU) containing 32 neurons, followed by the output layercontaining 2 neurons with softmax activation. The results showed that theANN, with an accuracy of 0,9892, could be a successful method to forecast theSwedish stock market instead of ARIMA.
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Permeability estimation of fracture networksJafari, Alireza 06 1900 (has links)
This dissertation aims to propose a new and practical method to obtain equivalent fracture network permeability (EFNP), which represents and replaces all the existing fractures located in each grid block for the reservoir simulation of naturally fractured reservoirs. To achieve this, first the relationship between different geometrical properties of fracture networks and their EFNP was studied. A MATLAB program was written to generate many different realizations of 2-D fracture networks by changing fracture length, density and also orientation. Next, twelve different 2-D fractal-statistical properties of the generated fracture networks were measured to quantify different characteristics. In addition to the 2-D fractal-statistical properties, readily available 1-D and 3-D data were also measured for the models showing variations of fracture properties in the Z-direction.
The actual EFNP of each fracture network was then measured using commercial software called FRACA. The relationship between the 1-, 2- and 3-D data and EFNP was analyzed using multivariable regression analysis and based on these analyses, correlations with different number of variables were proposed to estimate EFNP. To improve the accuracy of the predicted EFNP values, an artificial neural network with the back-propagation algorithm was also developed.
Then, using the experimental design technique, the impact of each fracture network parameter including fracture length, density, orientation and conductivity on EFNP was investigated. On the basis of the results and the analyses, the conditions to obtain EFNP for practical applications based on the available data (1-D well, 2-D outcrop, and 3-D welltest) were presented. This methodology was repeated for natural fracture patterns obtained mostly from the outcrops of different geothermal reservoirs. The validity of the equations was also tested against the real welltest data obtained from the fields.
Finally, the concept of the percolation theory was used to determine whether each fracture network in the domain is percolating (permeable) and to quantify the fracture connectivity, which controls the EFNP. For each randomly generated fracture network, the relationship between the combined fractal-percolation properties and the EFNP values was investigated and correlations for predicting the EFNP were proposed. As before, the results were validated with a new set of fracture networks. / Petroleum Engineering
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On the evolution of autonomous decision-making and communication in collective roboticsAmpatzis, Christos 10 November 2008 (has links)
In this thesis, we use evolutionary robotics techniques to automatically design and synthesise
behaviour for groups of simulated and real robots. Our contribution will be on
the design of non-trivial individual and collective behaviour; decisions about solitary or
social behaviour will be temporal and they will be interdependent with communicative
acts. In particular, we study time-based decision-making in a social context: how the
experiences of robots unfold in time and how these experiences influence their interaction
with the rest of the group. We propose three experiments based on non-trivial real-world
cooperative scenarios. First, we study social cooperative categorisation; signalling and
communication evolve in a task where the cooperation among robots is not a priori required.
The communication and categorisation skills of the robots are co-evolved from
scratch, and the emerging time-dependent individual and social behaviour are successfully
tested on real robots. Second, we show on real hardware evidence of the success of evolved
neuro-controllers when controlling two autonomous robots that have to grip each other
(autonomously self-assemble). Our experiment constitutes the first fully evolved approach
on such a task that requires sophisticated and fine sensory-motor coordination, and it
highlights the minimal conditions to achieve assembly in autonomous robots by reducing
the assumptions a priori made by the experimenter to a functional minimum. Third, we
present the first work in the literature to deal with the design of homogeneous control
mechanisms for morphologically heterogeneous robots, that is, robots that do not share
the same hardware characteristics. We show how artificial evolution designs individual
behaviours and communication protocols that allow the cooperation between robots of
different types, by using dynamical neural networks that specialise on-line, depending on
the nature of the morphology of each robot. The experiments briefly described above
contribute to the advancement of the state of the art in evolving neuro-controllers for
collective robotics both from an application-oriented, engineering point of view, as well as
from a more theoretical point of view.
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Analysis of surface finish in drilling of composites using neural networksMadiwal, Shashidhar 07 1900 (has links)
Composite materials are widely used in the aerospace industry because of their high strength-to-weight ratio. Although they have many advantages, their inhomogeneity and anisotropy pose problems. Because of these properties, machining of composites, unlike conventional metal working, needs more investigation. Conventional drilling of composites is one such field that requires extensive study and research. Among various parameters that determine the quality of a drilled hole, surface finish is of vital importance. The surface finish of a drilled hole depends on speed, feed-rate, material of the work piece, and geometry of the drill bit. This project studied the effect of speed and feed on surface finish and also the optimization of these parameters. Experiments were conducted based on Design of Experiment (DOE) and qualitative verification using Artificial Neural Network (ANN). Relevant behavior of surface finish was also studied. In this project, holes were drilled using a conventional twist drill at different cutting speeds (2,000 to 5,000 rpm) and feed rate was varied from 0.001 to 0.01 ipr for solid carbon fiber laminate (composite material). The other material drilled is BMS 8-276 form 3 (toughened resin system). Also five different drill bits were used to conduct experiments on BMS 8-276 form 3. Speed values were 5,000, 3,000, and 2,000 rpm and feed rates were 0.004, 0.006, and 0.01 ipr. The effect of speed, feed rate, and different drill geometries was analyzed with respect to surface finish in the drilled composites. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering. / "July 2006." / Includes bibliographic references (leaves 79-81).
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A functional link network based adaptive power system stabilizerSrinivasan, Saradha 02 September 2011
<p>An on-line identifier using Functional Link Network (FLN) and Pole-shift (PS) controller for power system stabilizer (PSS) application are presented in this thesis. To have the satisfactory performance of the PSS controller, over a wide range of operating conditions, it is desirable to adapt PSS parameters in real time. Artificial Neural Networks (ANNs) transform the inputs in a low-dimensional space to high-dimensional nonlinear hidden unit space and they have the ability to model the nonlinear characteristics of the power system. The ability of ANNs to learn makes them more suitable for use in adaptive control techniques.</p>
<p>On-line identification obtains a mathematical model at each sampling period to track the dynamic behavior of the plant. The ANN identifier consisting of a Functional link Network (FLN) is used for identifying the model parameters. A FLN model eliminates the need of hidden layer while retaining the nonlinear mapping capability of the neural network by using enhanced inputs. This network may be conveniently used for function approximation with faster convergence rate and lesser computational load.</p>
<p>The most commonly used Pole Assignment (PA) algorithm for adaptive control purposes assign the pole locations to fixed locations within the unit circle in the z-plane. It may not be optimum for different operating conditions. In this thesis, PS type of adaptive control algorithm is used. This algorithm, instead of assigning the closed-loop poles to fixed locations within the unit circle in the z-plane, this algorithm assumes that the pole characteristic polynomial of the closed-loop system has the same form as the pole characteristic of the open-loop system and shifts the open-loop poles radially towards the centre of the unit circle in the z-plane by a shifting factor α according to some rules. In this control algorithm, no coefficients need to be tuned manually, so manual parameter tuning (which is a drawback in conventional power system stabilizer) is minimized. The PS control algorithm uses the on-line updated ARMA parameters to calculate the new closed-loop poles of the system that are always inside the unit circle in the z-plane.</p>
<p>Simulation studies on a single-machine infinite bus and on a multi-machine power system for various operating condition changes, verify the effectiveness of the combined model of FLN identifier and PS control in damping the local and multi-mode oscillations occurring in the system. Simulation studies prove that the APSSs have significant benefits over conventional PSSs: performance improvement and no requirement for parameter tuning.</p>
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