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Periodinių sistemų parametrų įvertinimas / Estimation of the parameters ofperiodically time-varying systemGajevski, Pavel 11 June 2004 (has links)
In this work are discussed a block parameter estimation method for linear periodically time varying system. The whole work consists of two parts: theoretical and practical. The theoretical part is based on model’s description, its creation and structure. There it is shown estimation Markova, or an estimation of the least squares generalized method and the description of the generalized model. The practical part is devoted to fulfilling experiments and their describing. The conclusion about estimation of block parameter method’s achievement was also made. The experiments have been fulfilled using Matlab program. In addition count correctly Matlab (matrica, period) have been used. The results of experiments are given in the tables and schedules.
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Curvelet-domain preconditioned "wave-equation" depth-migration with sparseness and illumination constraintsHerrmann, Felix J., Moghaddam, Peyman P. January 2004 (has links)
A non-linear edge-preserving solution to the least-squares migration problem with sparseness & illumination constraints is proposed. The applied formalism explores Curvelets as basis functions. By virtue of their sparseness and locality, Curvelets not only reduce the dimensionality of the imaging problem but they also naturally lead to a dense preconditioning that almost diagonalizes the normal/Hessian operator.
This almost diagonalization allows us to recast the imaging problem into a ’simple’ denoising problem. As such, we are in the position to use non-linear estimators based on thresholding. These estimators exploit
the sparseness and locality of Curvelets and allow us to compute a first estimate for the reflectivity, which approximates the least-squares solution of the seismic inverse scattering problem. Given this estimate,
we impose sparseness and additional amplitude corrections by solving a constrained optimization problem. This optimization problem is initialized and constrained by the thresholded image and is designed to remove remaining imaging artifacts and imperfections in the estimation and reconstruction.
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Optimization strategies for sparseness- and continuity- enhanced imaging : TheoryHerrmann, Felix J., Moghaddam, Peyman P., Kirlin, Rodney L. January 2005 (has links)
Two complementary solution strategies to the least-squares migration problem with sparseness- & continuity constraints are proposed. The applied formalism explores the sparseness of curvelets on the reflectivity and their invariance under the demigration migration operator. Sparseness is enhanced by (approximately) minimizing a (weighted) l1-norm on the curvelet coefficients. Continuity along imaged reflectors is brought out by minimizing the anisotropic difussion or total variation norm which penalizes variations along and in between reflectors. A brief sketch of the theory is provided as well as a number of synthetic examples. Technical details on the implementation of the optimization strategies are deferred to an accompanying paper: implementation.
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Investigation of wireless local area network facilitated angle of arrival indoor locationWong, Carl Monway 11 1900 (has links)
As wireless devices become more common, the ability to position a wireless
device has become a topic of importance. Accurate positioning through
technologies such as the Global Positioning System is possible for outdoor
environments. Indoor environments pose a different challenge, and research
continues to position users indoors. Due to the prevalence of wireless local
area networks (WLANs) in many indoor spaces, it is prudent to determine
their capabilities for the purposes of positioning. Signal strength and time
based positioning systems have been studied for WLANs. Direction or angle
of arrival (AOA) based positioning will be possible with multiple antenna
arrays, such as those included with upcoming devices based on the IEEE
802.11n standard. The potential performance of such a system is evaluated.
The positioning performance of such a system depends on the accuracy
of the AOA estimation as well as the positioning algorithm. Two different
maximum-likelihood (ML) derived algorithms are used to determine the
AOA of the mobile user: a specialized simple ML algorithm, and the space-
alternating generalized expectation-maximization (SAGE) channel parameter estimation algorithm. The algorithms are used to determine the error
in estimating AOAs through the use of real wireless signals captured in an
indoor office environment.
The statistics of the AOA error are used in a positioning simulation
to predict the positioning performance. A least squares (LS) technique as
well as the popular extended Kalman filter (EKF) are used to combine the
AOAs to determine position. The position simulation shows that AOA-
based positioning using WLANs indoors has the potential to position a
wireless user with an accuracy of about 2 m. This is comparable to other
positioning systems previously developed for WLANs.
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Analysis of Additive Risk Model with High Dimensional Covariates Using Partial Least SquaresZhou, Yue 09 June 2006 (has links)
In this thesis, we consider the problem of constructing an additive risk model based on the right censored survival data to predict the survival times of the cancer patients, especially when the dimension of the covariates is much larger than the sample size. For microarray Gene Expression data, the number of gene expression levels is far greater than the number of samples. Such ¡°small n, large p¡± problems have attracted researchers to investigate the association between cancer patient survival times and gene expression profiles for recent few years. We apply Partial Least Squares to reduce the dimension of the covariates and get the corresponding latent variables (components), and these components are used as new regressors to fit the extensional additive risk model. Also we employ the time dependent AUC curve (area under the Receiver Operating Characteristic (ROC) curve) to assess how well the model predicts the survival time. Finally, this approach is illustrated by re-analysis of the well known AML data set and breast cancer data set. The results show that the model fits both of the data sets very well.
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PRODUCT MANAGEMENT AS FIRM CAPABILITYRoach, David 22 August 2011 (has links)
Product management as an organizational system has a long history of practice, which predates most modern academic management research. Its activities span the external environment of the firm, while simultaneously spanning across internal functional specialties of the organization. Thus product management obtains, codifies, simplifies and stores external information making it available to a responsive organization, which uses it to establish competitive advantage and ultimately superior performance.
Building on the resource based view of the firm and boundary theory, these spanning activities, which are heterogeneously dispersed across firms, are considered organizational capabilities. Drawing upon the extant product management literature, this research uses product management as a proxy for boundary spanning capabilities of the firm. These capabilities are then empirically measured against two well established firm capabilities; market orientation and firm-level innovativeness.
This research addresses a gap in the literature by establishing product management as a set of firm-level capabilities, distinct from the well established constructs of market orientation and innovativeness. Results indicate that external product management capability, defined as channel bonding activities, fully mediates the market orientation – firm performance relationship, while firm level innovativeness continues to have a small mediating effect on performance. Internal product management capabilities, defined as market and technical integration are shown to negatively moderate the external product management capability - firm performance relationship.
Theoretical implications include establishing a link between boundary theory and the resource based view of the firm. Practical implications include the strong relationship between external spanning capabilities and firm performance and the dampening effect of cross-functional integration on firm performance. This empirical link between product management boundary spanning practices and how firms ultimately perform could assist practitioners in allocating resources and managing the relationship between the marketing and technological factions of the organization. Most importantly this research establishes the hereto untested link between product management capability and firm performance.
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State Estimation in Electrical NetworksMosbah, Hossam 08 January 2013 (has links)
The continuous growth in power system electric grid by adding new substations lead to construct many new transmission lines, transformers, control devices, and circuit breakers to connect the capacity (generators) to the demand (loads). These components will have a very heavy influence on the performance of the electric grid. The renewable technical solutions for these issues can be found by robust algorithms which can give us a full picture of the current state of the electrical network by monitoring the behavior of phase and voltage magnitude.
In this thesis, the major idea is to implement several algorithms including weighted least square, extend kalman filter, and interior point method in three different electrical networks including IEEE 14, 30, and 118 to compare the performance of these algorithms which is represented by the behavior of phases and magnitude voltages as well as minimize the residual of the balance load flow real time measurements to distinguish which one is more robust. Also to have a particular understanding of the comparison between unconstraint and constraint algorithms.
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Hepatic Gene Expression Profiling to Predict Future Lactation Performance in Dairy CattleDoelman, John 07 October 2011 (has links)
An experiment was conducted to obtain a hepatic gene expression dataset from postpubertal dairy heifers that could be fit to a computational model capable of predicting future lactation performance values. The initial animal experiment was conducted to characterize the hepatic transcriptional response to 24-hour total feed withdrawal in one-hundred and two postpubertal Holstein dairy heifers using an 8329-gene oligonucleotide microarray in a randomized block design. Plasma concentration of non-esterified fatty acids was significantly higher, while levels of beta-hydroxybutyrate, triacylglycerol, and glucose were significantly lower with the 24-hour total feed withdrawal. In total, 505 differentially expressed genes were identified and microarray results were confirmed by real-time PCR. Upregulation of key gluconeogenic genes occurred despite diminished dietary substrate and lower hepatic glucose synthesis. Downregulation of ketogenic genes was contrary to the non-ruminant response to feed withdrawal, but was consistent with a lower ruminal supply of short-chain fatty acids as precursors. Following the microarray experiment, the first series of regression analyses was employed to identify relationships between gene expression signal and lactation performance measurements taken over the first lactation of 81 of the subjects from the original study. Regression models were evaluated using mean square prediction error (MSPE) and concordance correlation coefficient (CCC) analysis. The strongest validated stepwise regression models were constructed for milk protein percentage (r = 0.04) and lactation persistency (r = 0.09). To determine if another type of regression analysis would better predict lactation performance, partial least squares (PLS) regression analysis was then applied. Selection of gene expression data was based on an assessment of the linear dependence of all genes in normalized datasets for 81 subjects against 18 dairy herd index (DHI) variables using Pearson correlation analysis. Results were distributed into two lists based on correlation coefficient. Each gene expression dataset was used to construct PLS models for the purpose of predicting lactation performance. The strongest predictive models were generated for protein percentage (r = 0.46), 305-d milk yield (r = 0.44), and 305-d protein yield (r = 0.47). These results demonstrate the suitability of using hepatic gene expression in young animals to quantitatively predict future lactation performance. / Ontario Centre for Agricultural Genomics, NSERC Canada, and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)
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Data analysis for the classification of gas-liquid and liquid-solid (slurry) flows using digital signal processingFedon S., Roberto J Unknown Date
No description available.
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Post-manoeuvre and online parameter estimation for manned and unmanned aircraftJameson, Pierre-Daniel 07 1900 (has links)
Parameterised analytical models that describe the trimmed inflight behaviour of classical
aircraft have been studied and are widely accepted by the flight dynamics community.
Therefore, the primary role of aircraft parameter estimation is to quantify the parameter
values which make up the models and define the physical relationship of the air vehicle with
respect to its local environment. Nevertheless, a priori empirical predictions dependent
on aircraft design parameters also exist, and these provide a useful means of generating
preliminary values predicting the aircraft behaviour at the design stage. However, at
present the only feasible means that exist to actually prove and validate these parameter
values remains to extract them through physical experimentation either in a wind-tunnel
or from a flight test. With the advancement of UAVs, and in particular smaller UAVs
(less than 1m span) the ability to fly the full scale vehicle and generate flight test data
presents an exciting opportunity. Furthermore, UAV testing lends itself well to the ability
to perform rapid prototyping with the use of COTS equipment.
Real-time system identification was first used to monitor highly unstable aircraft behaviour
in non-linear flight regimes, while expanding the operational flight envelope. Recent
development has focused on creating self-healing control systems, such as adaptive
re-configurable control laws to provide robustness against airframe damage, control surface
failures or inflight icing. In the case of UAVs real-time identification, would facilitate rapid
prototyping especially in low-cost projects with their constrained development time. In
a small UAV scenario, flight trials could potentialy be focused towards dynamic model
validation, with the prior verification step done using the simulation environment. Furthermore,
the ability to check the estimated derivatives while the aircraft is flying would
enable detection of poor data readings due to deficient excitation manoeuvres or atmospheric
turbulence. Subsequently, appropriate action could then be taken while all the
equipment and personnel are in place.
This thesis describes the development of algorithms in order to perform online system
identification for UAVs which require minimal analyst intervention. Issues pertinent
to UAV applications were: the type of excitation manoeuvers needed and the necessary
instrumentation required to record air-data. Throughout the research, algorithm development
was undertaken using an in-house Simulink© model of the Aerosonde UAV which
provided a rapid and flexible means of generating simulated data for analysis. In addition,
the algorithms were further tested with real flight test data that was acquired from
the Cranfield University Jestream-31 aircraft G-NFLA during its routine operation as a
flying classroom. Two estimation methods were principally considered, the maximum likelihood
and least squares estimators, with the aforementioned found to be best suited to
the proposed requirements. In time-domain analysis reconstruction of the velocity state
derivatives ˙W and ˙V needed for the SPPO and DR modes respectively, provided more statistically
reliable parameter estimates without the need of a α- or β- vane. By formulating
the least squares method in the frequency domain, data issues regarding the removal of
bias and trim offsets could be more easily addressed while obtaining timely and reliable
parameter estimates. Finally, the importance of using an appropriate input to excite the
UAV dynamics allowing the vehicle to show its characteristics must be stressed.
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