bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infinite-dimensional Sylvester equations: Basic theory and application to observer design
Authors: Emirsajłow Zbigniew 
Published: June 2012

Infinite-dimensional Sylvester equations: Basic theory and application to observer design
This paper develops a mathematical framework for the infinite-dimensional Sylvester equation both in the differential and the algebraic form. It uses the implemented semigroup concept as the main mathematical tool. This concept may be found in the literature on evolution equations occurring in mathematics and physics and is rather unknown in systems and control theories. But it is just systems and control theory where Sylvester equations widely appear, and for this reason we intend to give a mathematically rigorous introduction to the subject which is tailored to researchers and postgraduate students working on systems and control. This goal motivates the assumptions under which the results are developed. As an important example of applications we study the problem of designing an asymptotic state observer for a linear infinite-dimensional control system with a bounded input operator and an unbounded output operator.
An SQP trust region method for solving the discrete-time linear quadratic control problem
Authors: Mostafa El-Sayed 
Published: June 2012

An SQP trust region method for solving the discrete-time linear quadratic control problemIn this paper, a sequential quadratic programming method combined with a trust region globalization strategy is analyzed and studied for solving a certain nonlinear constrained optimization problem with matrix variables. The optimization problem is derived from the infinite-horizon linear quadratic control problem for discrete-time systems when a complete set of state variables is not available. Moreover, a parametrization approach is introduced that does not require starting a feasible solution to initiate the proposed SQP trust region method. To demonstrate the effectiveness of the method, some numerical results are presented in detail.
Adaptive control of cluster-based Web systems using neuro-fuzzy models
Authors: Zatwarnicki Krzysztof 
Published: June 2012

Adaptive control of cluster-based Web systems using neuro-fuzzy modelsA significant development of Web technologies requires the application of more and more complex systems and algorithms for maintaining high quality of Web services. Presently, not only simple decision-making tools but also complex adaptation algorithms using artificial intelligence techniques are applied for controlling HTTP request traffic. The paper presents a new LFNRD (Local Fuzzy-Neural Adaptive Request Distribution) algorithm for request distribution in cluster-based Web systems using neuro-fuzzy models of Web servers in the decision-making process. The neuro-fuzzy model which is applied is discussed in detail and a design of the Web switch using the proposed solution is presented. Finally, a testbed is described and the results of a comparative simulation study on the LFNRD algorithm, and other algorithms known from the literature and used in the industry, are presented and discussed.
Existence and determination of the set of Metzler matrices for given stable polynomials
Authors: Kaczorek Tadeusz 
Published: June 2012

Existence and determination of the set of Metzler matrices for given stable polynomialsThe problem of the existence and determination of the set of Metzler matrices for given stable polynomials is formulated and solved. Necessary and sufficient conditions are established for the existence of the set of Metzler matrices for given stable polynomials. A procedure for finding the set of Metzler matrices for given stable polynomials is proposed and illustrated with numerical examples.
Straight-lines modelling using planar information for monocular SLAM
Authors: Santana André , Medeiros Adelardo 
Published: June 2012

Straight-lines modelling using planar information for monocular SLAMThis work proposes a SLAM (Simultaneous Localization And Mapping) solution based on an Extended Kalman Filter (EKF) in order to enable a robot to navigate along the environment using information from odometry and pre-existing lines on the floor. These lines are recognized by a Hough transform and are mapped into world measurements using a homography matrix. The prediction phase of the EKF is developed using an odometry model of the robot, and the updating makes use of the line parameters in Kalman equations without any intermediate stage for calculating the distance or the position. We show two experiments (indoor and outdoor) dealing with a real robot in order to validate the project.
A general on-the-fly algorithm for modifying the kinematic tree hierarchy
Authors: Stępień Jakub , Polański Andrzej , Wojciechowski Konrad 
Published: June 2012

A general on-the-fly algorithm for modifying the kinematic tree hierarchyWhen conducting a dynamic simulation of a multibody mechanical system, the model definition may need to be altered during the simulation course due to, e.g., changes in the way the system interacts with external objects. In this paper, we propose a general procedure for modifying simulation models of articulated figures, particularly useful when dealing with systems in time-varying contact with the environment. The proposed algorithm adjusts model connectivity, geometry and current state, producing its equivalent ready to be used by the simulation procedure. Furthermore, we also provide a simple usage scenario—a passive planar biped walker.
Improving prediction models applied in systems monitoring natural hazards and machinery
Authors: Sikora Marek , Sikora Beata 
Published: June 2012

Improving prediction models applied in systems monitoring natural hazards and machineryA method of combining three analytic techniques including regression rule induction, thek-nearest neighbors method and time series forecasting by means of the ARIMA methodology is presented. A decrease in the forecasting error while solving problems that concern natural hazards and machinery monitoring in coal mines was the main objective of the combined application of these techniques. The M5 algorithm was applied as a basic method of developing prediction models. In spite of an intensive development of regression rule induction algorithms and fuzzy-neural systems, the M5 algorithm is still characterized by the generalization ability and unbeatable time of data model creation competitive with other systems. In the paper, two solutions designed to decrease the mean square error of the obtained rules are presented. One consists in introducing into a set of conditional variables the so-called meta-variable (an analogy to constructive induction) whose values are determined by an autoregressive or the ARIMA model. The other shows that limitation of a data set on which the M5 algorithm operates by thek-nearest neighbor method can also lead to error decreasing. Moreover, three application examples of the presented solutions for data collected by systems of natural hazards and machinery monitoring in coal mines are described. In Appendix, results of several benchmark data sets analyses are given as a supplement of the presented results.
The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry
Authors: Khamsan Sorachai , Liawruangrath Saisunee , Teerawutkulrag Aphiwat , Pyne Stephen , Garson Mary , Liawruangrath Boonsom 
Published: June 2012

The isolation of bioactive flavonoids from Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry
The paper describes the bioassay-guided isolation, structure elucidation and anticancer evaluation of five flavonoids (-)-liquiritigenin (1), (-)-neoliquiritin (2), isoliquiritigenin (3), isoliquiritin (4) and formononetin (5) from the twigs of Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry. The structures were elucidated based on 1H, 13C NMR, comprehensive 2D NMR, MS analyses and comparison with previously reported spectral data. Compounds 1 and 3 were demonstrated to be inhibitory in vitro against NCI-H187 (small cell lung cancer) with IC50 values of 30.1 and 16.6 μg mL-1, respectively. The isolates were non-cytotoxic to Vero cells (African green monkey kidney).
Simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium using mean centering of the ratio spectra method
Authors: Ali Nouruddin , Hegazy Maha , Abdelkawy Mohamed , Abdelaleem Eglal 
Published: June 2012

Simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium using mean centering of the ratio spectra method
Accurate and sensitive methods were developed for simultaneous determination of methocarbamol and ibuprofen or diclofenac potassium in their binary mixtures, and in the presence of a methocarbamol related substance (guaifenesin) using mean centering of the ratio spectra method. The results obtained were statistically compared with the reported HPLC methods; no significant difference between the proposed methods and the reported methods was found regarding either accuracy or precision.
Equivalence Scale in Terms of Polish Households' Source of Income
Authors: Ulman Paweł 
Published: June 2012

Equivalence Scale in Terms of Polish Households' Source of Income
The paper presents a comparison of the costs of Polish households by their main source of income. In order to compare these costs the author estimated three kinds of equivalence scales using the Engel method, ELES (Extended Linear Expenditure System), the demand equation and the Bernoulli well-being function. Estimation for household groups determined on account of the main source of income produced by the scales confirmed differences in households' maintenance costs compared to the costs of the reference household. A comparison of the values of equivalence scales revealed a similarity of the results produced by the ELES and the Bernoulli methods which differed from the results obtained by means of the Engel method.
Maximal isokinetic peak torque and emg activity determined by shorter ranges of motion
Authors: Oliveira Anderson S.C. , Corvino Rogério B. , Gonçalves Mauro , Caputo Fabrizio , Denadai Benedito S. 
Published: June 2012

PurposeIsokinetic tests are often applied to assess muscular strength and EMG activity, however the specific ranges of motion used in testing (fully flexed or extended positions) might be constrictive and/or be painful for patients with injuries or undergoing rehabilitation. The aim of this study was to examine the effects of different ranges of motion (RoM) when determining maximal EMG during isokinetic knee flexion and extension with different types of contractions and velocities.MethodsEighteen males had EMG activity recorded on the vastus lateralis, vastus medialis, semitendinosus and biceps femoris muscles during five maximal isokinetic concentric and eccentric contractions for the knee flexors and extensors at 60° · s<sup>–1</sup> and 180° · s<sup>–1</sup>. The root mean square of EMG was calculated at three different ranges of motion: (1) a full range of motion (90°–20° [0° = full knee extension]); (2) a range of motion of 20° (between 60°–80° and 40°–60° for knee extension and flexion, respectively) and (3) at a 10° interval around the angle where peak torque is produced. EMG measurements were statistically analyzed (ANOVA) to test for the range of motion, contraction velocity and contraction speed effects. Coefficients of variation and Pearson’s correlation coefficients were also calculated among the ranges of motion.ResultsPredominantly similar (<i>p</i> > 0.05) and well-correlated EMG results (<i>r</i> > 0.7, <i>p</i> < 0.001) were found among the ranges of motion. However, a lower coefficient of variation was found for the full range of motion, while the 10° interval around peak torque at 180° · s<sup>–1</sup> had the highest coefficient, regardless of the type of contraction.ConclusionsShorter ranges of motion at around the peak torque angle provides a reliable indicator when recording EMG activity during maximal isokinetic parameters. It may provide a safer alternative when testing patients with injuries or undergoing rehabilitation.
Analysis of body posture between young football players and their untrained peers
Authors: Grabara Małgorzata 
Published: June 2012

PurposeThe aim of this study was to analyze the body posture of young football players and their untrained peers.MethodsA group of 73 football players and 78 untrained boys, all aged between 11 and 14 years, were studied by measuring body posture indices with computer posturography (the MORIE technique). Spinal angles and curvatures in the sagittal plane and body posture asymmetry in the frontal and transversal plane were measured. Body height and mass and BMI were also determined.ResultsCompared to the untrained boys, the group of football players had lower BMI. The position of pelvis in the frontal plane was more symmetrical (<i>p</i> < 0.001) in football players, but the alignment of the remaining measured parameters was similar between the two groups except for the horizontal symmetry of the waist triangles (a higher incidence of symmetry in some ages groups of football players) and the horizontal symmetry of the shoulder blades (a higher incidence of asymmetry in some ages groups of football players). A postural symmetry index that was created for this study did not find any differentiation among the studied groups. The spinal alignment of the football players featured a more flattened lumbar lordosis.ConclusionsPreviously conducted studies on the body posture of young athletes are still not ample and complete, while the results do not clearly indicate the development of posture when subjected to sports training.
A comparative analysis of the anthropometric method and bioelectrical impedance analysis on changes in body composition of female volleyball players during the 2010/2011 season
Authors: Buśko Krzysztof , Lipińska Monika 
Published: June 2012

PurposeThe aim of this study was to observe the changes in body composition by using two measurement methods – anthropometric analysis and bioelectrical impedance analysis (BIA) – on a group female volleyball players and to compare the results of both methods.MethodsEleven female volleyball players participated in this study during the 2010/2011 season. Measurements of body composition were performed with an electronic body composition analyzer (BIA method) adjusted for STANDARD physical activity levels and then using the anthropometric method as per Piechaczek’s formula. Total lean body mass (LBM), total body fat content (FAT) and body water content were measured. Measurements were taken before preseason training (Measurement 0), one week before the end of preseason training (Measurement 1), after the first (Measurement 2) and the second (Measurement 3) half of the competitive season and four weeks after the seasons’ playoffs during the offseason (Measurement 4). Additionally, during Measurement 4, body composition measured by the BIA method was adjusted for ATHLETIC physical activity levels.ResultsBody mass, lean body mass and body water content did not change throughout the analyzed period. Body fat mass, as determined by BIASTANDARD, increased from 20.7 ± 5.3 kg (Measurement 0) to 22.2 ± 5.0 kg (Measurement 1) but subsequently decreased to 21.2 ± 5.7 kg (Measurement 2) and remained at this level until the end of the competitive season. In the case of body fat as measured by the anthropometric method, a significant increase in fat was observed from 18.4 ± 3.0 kg to 19.3 ± 3.4 kg and then from 19.5 ± 3.5 kg to 19.8 ± 3.6 kg. Analysis of LBM and FAT values found significant differences between the values obtained using the BIA method at the ATHLETIC physical activity level and the results registered at the STANDARD level and those recorded by use of the anthropometric method.ConclusionsThe results obtained using the BIA method set at the STANDARD mode of physical activity and those by the anthropometric method did not significantly differ. Significant correlation between the values obtained by the BIA method and anthropometric method was found.
Lake Engure catchment area as an example of the interaction of natural conditions, settlement pattern and economic activities
Authors: Strautnieks Ivars , Grīne Ineta 
Published: June 2012

Lake Engure catchment area as an example of the interaction of natural conditions, settlement pattern and economic activities
The authors have written this paper as an overview of the area, which includes earlier published data and the results of a new, original research. It covers the geological structure, including a characterisation of the geology of the Sub-Quaternary surface. Described in greater detail are the Quaternary cover and the surface relief, as well as the hypsometry, which in many locations directly influence the conditions of surface drainage, soil development and landscape characteristics. Based on the morphology and internal structure of the relief, the main stages in the formation of the relief are also outlined, in effect marking temporal differences in landscape development. The influence of these factors, as well as a string of other natural factors (groundwater and surface drainage, the proximity of the sea) within distinct parts of the study area, explain the character of human economic activities, the development of settlement and the traditions that have continued over the centuries. Several different areas are clearly distinguishable in functional terms: 1) the area where farming is the characteristic activity, 2) the area used for fishing and recreation, 3) forested areas, with soils unsuitable for agriculture. The form and intensity of land use also determine the distribution of settlements and population size.
Reconstruction of past anthropogenic impact intensity in Lake Engure using sedimentary record analysis
Authors: Kļaviņš Māris , Pujāte Agnese , Kokorīte Ilga , Kalniņa Laimdota , Rodinovs Valērijs , Ansone Linda , Mažeika Jonas , Jankēvica Maruta , Bogans Egils , Švāgere Anda 
Published: June 2012

Reconstruction of past anthropogenic impact intensity in Lake Engure using sedimentary record analysis
Environmental pollution with trace elements is considered as one of the most important environmental problems. Analysis of trace element accumulation in sedimentary phases of lakes may reflect the overall regional pollution level, and analysis of trace element accumulation patterns in sediment profiles can help to reconstruct the history of anthropogenic impact. The aim of this study was to analyse trace element concentrations in sediments of Lake Engure in Latvia and to determine factors influencing their availability. The metal concentrations in sediments of Lake Engure are at background levels, especially compared with metal concentrations in West European countries. However, the change in element concentration in sedimentary profiles provides information about trends of recent accumulation (within the last 100 years) and on the balance between natural and human-induced accumulation processes.
Influence of waste liquors of mildronate production on yield and quality of winter rapeseed
Authors: Bremanis Gunārs , Maļecka Solveiga 
Published: June 2012

Influence of waste liquors of mildronate production on yield and quality of winter rapeseed
The effect of mother liquors obtained in one production stage of the popular medicinal preparation Mildronate on yield and quality of winter rape (Brassica napus L.) grown for biofuel was tested. The mother liquors contain quaterine-type compounds, which are known to stimulate growth of lupines. In the three-year study, Mildronate mother liquors were sprayed on winter rape. The yield and fat content of rape was determined. Mother liquor contains small amounts of methyl acrylate. However, this compound was not found in rapeseed, stalks and soil. Mother liquors spray had a positive effect on soil microorganisms. In the period from initiation of flowering to maximum flowering stage, spraying with mother liquors, as well as with quaterine-M and isopropanol (basic substance of mother liquor), in most cases had a low (around 10%) positive effect on rape yield and a very small impact on the fat content in rape grain. The effects differed among years, suggesting interaction with weather conditions. The determined optimal mother liquors dosages were quite wide, from 0.4 to 10 L ha-1.
Results of monitoring of the population of Blumeria graminis f.sp. hordei in Latvia in 2009-2010
Authors: Kokina Inese , Rashal Isaak 
Published: June 2012

Results of monitoring of the population ofBlumeria graminisf.sp.hordeiin Latvia in 2009-2010In 2009-2010, random samples of the causal agent of barley powdery mildew were collected in Daugavpils (south-eastern Latvia, Latgale region), Stende (north-western Latvia, Kurzeme region) and Priekuļi (north-eastern Latvia, Vidzeme region). Virulence frequency, complexity and pathotypes were calculated in the pathogen populations. Significant differences of virulence detected by the genesVa1, Va3and Va13occurred among samples of the pathogen population collected in different parts of Latvia. Nei index, Müller's index, Kosman index, Shannon index and Simpson index showed considerably higher diversity in Daugavpils and Stende during 2009-2010. In Daugavpils, the population ofBlumeria graminisf.sp.hordei was particularly characterised by high diversity.
Casting Routes for Porous Metals Production
Authors: Lichy P. , Bednarova V. , Elbel T. 
Published: June 2012

Casting Routes for Porous Metals Production
The last decade has seen growing interest in professional public about applications of porous metallic materials. Porous metals represent a new type of materials with low densities, large specific surface, and novel physical and mechanical properties, characterized by low density and large specific surface. They are very suitable for specific applications due to good combination of physical and mechanical properties such as high specific strength and high energy absorption capability. Since the discovery of metal foams have been developed many methods and techniques of production in liquid, solid and gas phases. Condition for the use of metal foams - advanced materials with unique usability features, are inexpensive ways to manage their production. Mastering of production of metallic foams with defined structure and properties using gravity casting into sand or metallic foundry moulds will contribute to an expansion of the assortment produced in foundries by completely new type of material, which has unique service properties thanks to its structure, and which fulfils the current demanding ecological requirements. The aim of research conducted at the department of metallurgy and foundry of VSB-Technical University Ostrava is to verify the possibilities of production of metallic foams by conventional foundry processes, to study the process conditions and physical and mechanical properties of metal foam produced. Two procedures are used to create porous metal structures: Infiltration of liquid metal into the mold cavity filled with precursors or preforms and two stage investment casting.