Wyniki wyszukiwania - Biblioteka Nauki

1

Analysis of pole coordinate data predictions in the Earth Orientation Parameters Combination of Prediction Pilot Project

100%

Kosek W. , Luzum B. , Kalarus M. , Wnęk A. , Zbylut M.

Artificial Satellites : Journal of Planetary Geodesy

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2011

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tom Vol. 46, No. 4

139--150

EN

In October 2010 the US Naval Observatory together with the Space Research Centre in Warsaw initiated the Earth Orientation Parameters Combination of Prediction Pilot Project, which was accepted by the IERS Directing Board. The goal of this project is to determine the feasibility of combining Earth Orientation Parameters (EOP) predictions on an operational basis. The ensemble predictions of EOPs are more accurate than the results from individual predictions. The pole coordinate data predictions from different prediction contributors and ensemble predictions computed by the U.S. Naval Observatory are studied to determine the statistical properties of polar motion forecasts by looking at second, third and fourth moments about the mean. The increase of prediction errors in pole coordinate data can be due to the change of phase of the annual oscillation in the joint atmospheric-ocean excitation function.

2

A new methodology that surpasses current bridging theories to efficiently seal a varied pore throat distribution as found in natural reservoir formations

100%

Vickers S. , Cowie M. , Jones T. , Twynam A. J.

Wiertnictwo, Nafta, Gaz

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2006

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tom R. 23/1

501-515

EN

This paper presents a new method (model) for predicting the most efficient way to create a particle bridge on a formation face having a wide spread of pore throat sizes. Laboratory data, based on particle bridging distributions using this new model, are shown to be an improvement over two current industry methods. The improvement using this design has been effective in the field and has resulted high productivity

PL

W artykule przedstawiono mową metodę (model) przewidywania najbardziej skutecznych sposobów tworzenia mostków utworzonych z cząstek na czole formacji o szerokim rozkładzie kanalików w przestrzeni porowej. Badania laboratoryjne nad tym modelem wykazały, że ma on istotną przewagę nad dwom dotychczas stosowanymi w przemyśle metodami. Nowa metoda okazała się skuteczna w warunkach terenowych i zaowocowała zwiększoną produkcją

3

Employing combination procedures to short-time EOP prediction

100%

Malkin Z.

Artificial Satellites : Journal of Planetary Geodesy

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2010

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tom Vol. 45, No. 2

87--93

EN

A well known problem with Earth Orientation Parameters (EOP) prediction is that a prediction strategy proved to be the best for some testing time span and prediction length may not remain the same for other time intervals. In this paper, we consider possible strategies to combine EOP predictions computed using different analysis techniques to obtain a final prediction with the best accuracy corresponding to the smallest prediction error of input predictions. It was found that this approach is most efficient for ultra-short-term EOP forecast.

4

Machine learning and traditional econometric models : a systematic mapping study

80%

Pérez-Pons M. E. , Parra-Dominguez J. , Omatu S. , Herrera-Viedma E. , Corchado J. M.

Journal of Artificial Intelligence and Soft Computing Research

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2022

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tom Vol. 12, No. 2

79--100

EN

Machine Learning (ML) is a disruptive concept that has given rise to and generated interest in different applications in many fields of study. The purpose of Machine Learning is to solve real-life problems by automatically learning and improving from experience without being explicitly programmed for a specific problem, but for a generic type of problem. This article approaches the different applications of ML in a series of econometric methods. Objective: The objective of this research is to identify the latest applications and do a comparative study of the performance of econometric and ML models. The study aimed to find empirical evidence for the performance of ML algorithms being superior to traditional econometric models. The Methodology of systematic mapping of literature has been followed to carry out this research, according to the guidelines established by [39], and [58] that facilitate the identification of studies published about this subject. Results: The results show, that in most cases ML outperforms econometric models, while in other cases the best performance has been achieved by combining traditional methods and ML applications. Conclusion: inclusion and exclusions criteria have been applied and 52 articles closely related articles have been reviewed. The conclusion drawn from this research is that it is a field that is growing, which is something that is well known nowadays and that there is no certainty as to the performance of ML being always superior to that of econometric models.

5

Critical infrastructure operation process

80%

Kołowrocki K. , Soszyńska-Budny J.

Journal of Polish Safety and Reliability Association

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2017

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tom Vol. 8, No. 2

1--6

EN

The operation process of the critical infrastructure is considered and its operation states are introduced. The semi- Markov process is used to construct a general probabilistic model of the critical infrastructure operation process.

6

Taxonomic and Econometric Analysis of Road Transport Development in Poland – The Voivodship Approach

80%

Czech A. , Lewczuk J.

Ekonomia i Zarzadzanie

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2016

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tom 8

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nr 3

79-88

EN

Transport is considered one of the basic aspects of the movement of people, raw materials as well as goods from the place of origin to the destination. Moreover, in the wider sense, transport includes economic bodies that aim to achieve goals similar to those of businesses that produce a wide range of goods required by customers. Hence, the efficient operations of basic branches of the transportation system determine the entire national economy. Furthermore, transport is considered a basic factor of development, both on the macro- and microeconomic scales. The aim of the paper is to attempt the assessment of the road transport in Poland as an important element of macro logistics. Furthermore, one of the aims of the investigation was the explanation of its influence on the level of economic development in Poland. As the source of information, the research used the data drawn from the Central Statistical Office of Poland. The main methods implemented in this study were both classic and order synthetic measure construction. Further, these measures were used in econometric models as well as for the prediction of their values. The main result of the analysis indicates that the development level of the widely considered infrastructure is strictly correlated with the socio-economic development of particular voivodships. The study on the level of road transport development can lead to a better understanding of the socio-economic development of particular areas of Poland as well as the more efficient use of the support funds.

7

Estimation of VO2MAX According to The 3’Bike Test

80%

Rexhepi A. M. , Brestovci B.

Human Movement

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2012

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tom 13

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nr 4

367-371

EN

Purpose. The aim of this study was to derive the regression equation for predicting VO2max of athletes by the relatively new submaximal 3'Bike Test. Methods. This test was conducted on 1501 active football male players, aged 16÷35 years. A medical anamnesis was administered and then the athletes’ weight was measured. Afterwards, the athletes performed the 3'Bike Test followed by the Astrand Bike Test for comparison reasons. Results. Linear regression of the data indicated that the produced regression model, as a whole, is statistically significant. In addition, the system of predictive variables was able to explain for 48% of total variability of the criterion variable VO2maxAST. According to the regression coefficients that had been derived, a regression equation that could predict VO2max was created. A significant high correlation (r = 0.688) and a non-significant paired t-test (p = 0.782) found between the measured VO2max (Astrand test) and the predicted VO2max (3'Bike Test) indicates a large similarity between the predicted and measured VO2max values. Conclusions. The 3'Bike Test was found to be a capable measurement tool of aerobic endurance, more reliable and valid than the Astrand submaximal test, as well as being shorter, more easily executed and a better predictor of VO2max.

8

Improving the Performance of Cognitive Radios through Classification, Learning, and Predictive Channel Selection

80%

Höyhtyä M. , Pollin S. , Mämmelä A.

Advances in Electronics and Telecommunications

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2011

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tom Vol. 2, no. 4

28--38

EN

Prediction of future idle times of different channels based on history information allows a cognitive radio (CR) to select the best channels for control and data transmission. In contrast to earlier work, the proposed method works not only with a specific type of traffic but learns and classifies the traffic type of each channel over time and can select the prediction method based on that. Different prediction rules apply to partially deterministic and stochastic ON-OFF patterns. New prediction methods for both traffic classes are developed in the paper. A CR predicts how long the channels are going to be idle. The channel with the longest predicted idle time is selected for secondary use. Simulations show that the proposed classification method works well and redictive channel selection method outperforms opportunistic random channel selection both with stochastic and deterministic ON-OFF patterns. Weibull, Pareto, and exponentially distributed traffic patterns are used in stochastic simulations to show general applicability of the proposed method. The classification-based method has even a higher gain when channels of interest include both stochastic and deterministic traffic. The collision rate with primary user over a given time interval can drop by more than 70% compared to the predictive system operating without classification.

9

Future of Earth orientation predictions

80%

Luzum B.

Artificial Satellites : Journal of Planetary Geodesy

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2010

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tom Vol. 45, No. 2

107--110

EN

Earth orientation prediction has undergone a number of changes over the last few decades in response to changing conditions in the Earth orientation parameter user community. However, considering the recent pace of change, it is likely that the rate at which innovations are introduced into the prediction process will increase. Potential drivers for change are discussed and possible directions for change are outlined.

10

Experimental and Predicted Thermodynamic Properties of Mixtures Containing Corn Oil with Ketones and Alkanes Employed in Their Refine

80%

Resa J. , Gonzales C. , Concha R. , Goenaga J.

Polish Journal of Chemistry

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2006

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tom Vol. 80, nr 1

129-141

EN

We present new experimental data of density, refractive index, speed of sound and viscosity for the binaries of corn oil + (n-hexane,n-heptane, n-octane, 2-butanone, 3-pentanone and 4-methyl-2-pentanone) at T = 298.15 K and standard conditions, and the corresponding computed derived magnitudes (change of isentropic compressibility, change of refractive index on mixing and excess molar volume). A good agreement among experimental data and the values estimated by theoretical procedures was obtained.

11

Application of grey model GM(1, 1) to ultra short-term predictions of universal time

80%

Lei Y. , Guo M. , Zhao D. , Cai H. , Hu D.

Artificial Satellites : Journal of Planetary Geodesy

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2016

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tom Vol. 51, No. 1

19--29

EN

A mathematical model known as one-order one-variable grey differential equation model GM(1, 1) has been herein employed successfully for the ultra short-term (<10days) predictions of universal time (UT1-UTC). The results of predictions are analyzed and compared with those obtained by other methods. It is shown that the accuracy of the predictions is comparable with that obtained by other prediction methods. The proposed method is able to yield an exact prediction even though only a few observations are provided. Hence it is very valuable in the case of a small size dataset since traditional methods, e.g., least-squares (LS) extrapolation, require longer data span to make a good forecast. In addition, these results can be obtained without making any assumption about an original dataset, and thus is of high reliability. Another advantage is that the developed method is easy to use. All these reveal a great potential of the GM(1, 1) model for UT1-UTC predictions.

12

Critical infrastructure operation process related to climate-weather change process including extreme weather hazard

80%

Kołowrocki K. , Soszyńska-Budny J. , Torbicki M.

Journal of Polish Safety and Reliability Association

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2017

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tom Vol. 8, No. 2

25--40

EN

The operation process of the critical infrastructure is considered and its operation states are introduced. The semi-Markov process is used to construct a general probabilistic model of the critical infrastructure operation process. The semi-Markov process is used to construct a general probabilistic model of the climate-weather change process for the critical infrastructure operating area.

13

Influence of tool wear on material flow

80%

Schindlerová V. , Šajdlerová I.

Advances in Science and Technology. Research Journal

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2017

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tom Vol. 11, no 1

161--165

EN

The cold bulk forming is a technology that is commonly used in many industrial enterprises. Even though nowadays high demands are posed on labour productivity, quality and own production costs, the findings from practice suggest that not sufficient attention is paid to the issue of tool management. Also, theoretical backgrounds and knowledge in this area are not processed in a sufficiently detailed and comprehensive way. This paper deals with the issue of prediction of the wear surface of the forming tools and their subsequent renewal. The research at selected materials was focused on the course of their straining in contact of the blank with the tool in the process of cold bulk forming. The experiments were based on a simple performance of the conventional upsetting test. On the basis of analysis of the results the mechanism of tool wear by abrasion was determined and its impact on the service life time of the tool and also the possibility of influencing the quality of final parts were evaluated.

14

Wykorzystanie sztucznych sieci neuronowych do prognozowania wyników meczów piłkarskich

80%

BARTMAN J. , BAJDA K.

Edukacja-Technika-Informatyka

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2014

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tom 5

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nr 2

425-431

PL

W pracy zaprezentowano koncepcję wykorzystania Sztucznych Sieci Neuronowych do prognozowania wyników meczów. Przedstawiono architekturę sieci oraz skuteczność realizowanych przez nią prognoz. Uzyskane wyniki zestawiono z wynikami otrzymanymi przy wykorzystaniu innych metod.

EN

The paper presents the concept of using Artificial Neural Networks to predict the results of football matches. Autors presents the architecture of the network and the effectiveness of the implementation by the forecasts. The results were compared with results obtained using other methods

15

Characterization of Propagation Models in Wireless Communications for 4G Network

80%

Al-Aamri N. , Nadir Z. , Al-Lawati H. , Suwailam M. B.

International Journal of Electronics and Telecommunications

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2022

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tom Vol. 68, No. 1

137--143

EN

Estimating the pathloss and signal strength of the transmitted signal at specific distances is one of the main objectives of network designers. This paper aims to provide generalized pathloss models appropriate for urban areas in Muscat the capital city of the Sultanate of Oman environment. The research includes studying different models of pathloss for the 4G cellular network at Muttrah Business District (MBD) at Muscat. Different models (Free Space model, Okumura Hata, Extended Sakagami, Cost231 Hata, ECC-33 Hata – Okumura extended, Ericsson, Egli, and SUI) are used with 800MHz. The results of the prediction models are compared with real measured data by calculating RMSE. The generalized models are created by modified original models to get accepted RMSE values. Different cells at MBD are tested by modified models. The RMSE values are then calculated for verification purposes. To validate the modified pathloss models of 4G, they are also applied at different cells in a different city in the capital. It has approximately the same environment as MBD. The modified pathloss models provided accepted predictions in new locations.

16

EU-CIRCLE: A pan-European framework for strengthening critical infrastructure resilience to climate change Project taxonomy and methodology : Critical infrastructure accident consequences terminology and methodology

80%

Bogalecka M. , Kołowrocki K.

Journal of Polish Safety and Reliability Association

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2017

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tom Vol. 8, No. 1

247--258

EN

The paper presents critical infrastructure accident consequences terminology, used in the project titled “A panEuropean framework for strengthening Critical Infrastructure resilience to climate change – EU-CIRCLE”, realized under the European Union’s Horizon 2020 research and innovation program. The methodology concerned with EU-CIRCLE project Case Study 2, investigating chemical spill due to extreme surges related to critical infrastructure accident consequences modelling in the scope of project issues is proposed as well.

17

Tree crown ratio model for Hevea brasiliensis (A. juss.) plantation in Rubber Research Institute of Nigeria (RRIN) Edo State, Nigeria

80%

Oyebade B. A. , Onyeoguzoro T. C.

World Scientific News

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2017

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tom 70

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nr 2

97-110

EN

Crown ratio is a term used to describe the ratio of the crown length to the total tree height. The crown length emphasizes the distance between the crown apex and the crown point while the distance between the tree apex and the ground level defines the total tree height. The tree crown ratio are predicted by the use of empirical models which assist in the provision of accurate estimates for both individual, stand growth as well as yield that are veritable tools for evaluating numerous management and utilization decision. However, no single type of model can provide sufficient information effectively for all levels of decision making, thus the essence of modeling tree crown ratio for Hevea brasiliensis plantation in Rubber Research Institute of Nigeria (RRIN). Tree growth variables are such as diameter at the base (DB), diameter at the breast height (DBH), crown diameter (CD), crown length (CL), total tree height (THT) were measured from a six year old plantation of 402 trees, while tree attributes such as crown projection area (CPA), basal area (BA), tree slenderness coefficient (TSC), crown ratio (CR) were estimated using their empirical formula. The data collected from the plantation was analyzed using descriptive and inferential statistics such as correlation and regression analyses with non-linear models used in fitting the data into CR equations and other growth attributed with individual data fitted to evaluate the robustness of the models using the fit indices. The result of the study reveals that there were significant variations in the growth attributes within the plantation in the study area. The result of the correlation analysis between CR and other growth characteristics revealed significant associations. The best adjudged CR model was the logistics model which is represented as CR=a_0/(1-e^(^(1-a_(1 ) CL+a_2 THT)) ) ; (R2 = 0.96 and SSE = 0.1177). The study has shown that crown ratio models developed has significant relationship with CL and THT and this can be successfully used for predictive studies on crown attributes for Hevea brasiliensis plantations in Nigeria.

18

Vehicle navigation in populated areas using predictive control with environmental uncertainty handling

80%

Skrzypczyk K. , Mellado M.

Archives of Control Sciences

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2017

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tom Vol. 27, no. 2

351--359

EN

This paper addresses the problem of navigating an autonomous vehicle using environmental dynamics prediction. The usefulness of the Game Against Nature formalism adapted to modelling environmental prediction uncertainty is discussed. The possibility of the control law synthesis on the basis of strategies against Nature is presented. The properties and effectiveness of the approach presented are verified by simulations carried out in MATLAB.

19

Unbiased Recursive Partitioning Algorithm in Regression Trees

80%

Rozmus D. , Department of Statistics T. K. A. U. o. E.

Acta Universitatis Lodziensis. Folia Oeconomica

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2009

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tom 228

PL

Drzewa klasyfikacyjne i regresyjne są bardzo popularnym narzędziem predykcji. Budowa takiego modelu polega na stopniowym podziale wielowymiarowej przestrzeni cech na rozłączne obszary aż do uzyskania maksymalnej ich homogeniczności ze względu na wartość zmiennej objaśnianej y. Podział ten kontynuowany jest w kolejnych krokach, w oparciu o wartości wybranych zmiennych objaśniających. Istnieje wiele możliwych sposobów wyboru tych zmiennych, a jednym z najpopularniejszych jest algorytm wyczerpującego przeszukiwania (ang. exhaustive search) opracowany przez Breimana (Breimana et al., 1984). Zaproponowany przez Hothoma, Hornika i Zeileisa, (2006) sposób doboru zmiennych znany pod nazwą nieobciążonej metody rekurencyjnego podziału (ang. unbiased recurcive partitioning) opierający się na zastosowaniu testów permutacyjnych miał na celu ominięcie podstawowej wady tradycyjnego podejścia, jakim jest tendencja do wyboru zmiennych dających wiele potencjalnych możliwości podziału. Okazuje się, że w przypadku dyskryminacji to nowatorskie podejście prowadzi do uzyskania modeli zapewniających bardzo zbliżone wyniki klasyfikacji jak podejście tradycyjne, a w podejściu wielomodelowym może doprowadzić do pogorszenia poprawności klasyfikacji. Zasadniczym celem referatu jest przedstawienie wyników badań, które mają na celu porównanie dokładności predykcji na podstawie drzew regresyjnych, które doboru zmiennych objaśniających dokonują za pomocą algorytmu wyczerpującego przeszukiwania oraz za pomocą podejścia bazującego na testach permutacyjnych. Ponadto porównane zostaną wyniki predykcji modeli zagregowanych, w których modelami składowymi będą te dwa rodzaje drzew regresyjnych.

EN

Classification and regression trees are very popular tool for prediction. The construction of these models is based on recursive partitioning of multidimensional attribute space into disjoint homogenous regions till gaining the maximum homogeneity from the point of view of the dependent variable value. The main aim of this research is to apply in regression trees unbiased recursive partitioning algorithm proposed by Hothom, Homik and Zeileis (2006), which is based on permutation tests. The research takes into consideration both single and aggregated approach and compare the results with classical method of tree model construction based on exhaustive search algorithm proposed by Breiman et al. (1984).

20

On Time Series Prediction Based on Control Chart

80%

Polko D. , Kończak G. , Katowice University of Economics D. o. S. , Katowice University of Economics D. o. S. , dpolko@gmail.com , grzegorz.konczak@ue.katowice.pl

Acta Universitatis Lodziensis. Folia Oeconomica

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2013

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tom 286

EN

Control charts are the most commonly used quality control tools. These tools are dedicated to monitoring processes characteristic over time. Control charts may be successfully applied in other statistical areas. The non-classical use of control charts for time series prediction has been presented by Z. Pawłowski in the paper Predykcja za pomocą kart kontrolnych (Control Chart Based Prediction, 1969). The forecasts obtained by this method are quantitative or qualitative. The modification of this method is presented in the paper. It leads to quantitative predictions in all cases. The proposal was compared to some well-known classical prediction methods in the Monte Carlo study.

PL

Metody statystyczne opracowane na potrzeby kontroli jakości produktów z powodzeniem mogą być stosowane w analizie innych zagadnień. Do najczęściej wykorzystywanych narzędzi kontroli jakości należy zaliczyć karty kontrolne. Nieklasyczne zastosowanie kart kontrolnych związane z wykorzystaniem ich do prognozowania przedstawił Z. Pawłowski w artykule Predykcja za pomocą kart kontrolnych (1969). Prognozy otrzymywane tą metodą mają charakter ilościowy lub jakościowy. W artykule przedstawiono propozycję modyfikacji tej metody w celu uzyskania wszystkich prognoz o charakterze ilościowym. Proponowaną metodę porównano symulacyjnie z wybranymi metodami predykcji.