Skocz do pozycji: 1.

Tytuł:

Principal Component Analysis in the Study of Structure of the Best Polish Decathlon Competitors from the Period between 1985–2015

Autorzy:

Dziadek, Bartosz
Iskra, Janusz
Przednowek, Krzysztof

Powiązania:

https://bibliotekanauki.pl/articles/1030587.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego

Tematy:

decathlon
principal component analysis
sport career

Opis:

The modern decathlon is a sport consisting of ten different events held over two days, played by men. Depending on the complexity of combined events, variety of events (runs, throws, jumps), the multi-stage, time-consuming and difficult training process the sport is considered as one of the most difficult. The analysis of careers of the best decathlon participants and applying advanced data-mining methods can help define the patterns occurring between each decathlon event and the final result. The research material encompasses career data of the 25 top competitors from Poland in years 1985–2015. Principal component analysis (PCA) was used in the research in order to designate new uncorrelated variables (components), representing input data across a new plane. Data analysis involved appointment of correlations between the events, determining the number of main components taken into account in further studies, analysis of the weight of each variable in formation of main components as well as visualisation and interpretation of results in the new plane described by the determined main components. Through the implementation of PCA method in the process of analysis it was possible to designate over 69% of compound data volatility with the use of the first three components. The first component, comprised of seven variables, displays the largest share in the total variability. The study of the relationship between variables in the new plane displayed strong correlations between sprint events (100 m, 110 m hurdles) and long jump and pole vault. No correlations between the 1500 m run and other events were found.

Źródło:

Central European Journal of Sport Sciences and Medicine; 2018, 23, 3; 77-87
2300-9705
2353-2807

Pojawia się w:

Central European Journal of Sport Sciences and Medicine

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:

Principal Component Analysis of Egg Quality Characteristics of Isa Brown Layer Chickens in Nigeria

Autorzy:

Ukwu, H. O.
Abari, P. O.
Kuusu, D. J.

Powiązania:

https://bibliotekanauki.pl/articles/1178566.pdf

Data publikacji:

2017

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Correlation
Egg
Isa brown
Principal component
Quality

Opis:

This study was designed to provide an objective description of egg quality of Isa brown layer chickens in Nigeria. 104 eggs were used for the study. The eggs were initially weighed individually using a sensitive electronic weighing balance with accuracy of 0.001g. Data were collected on egg weight, egg length, egg width, oblong circumference, egg shell weight, yolk height, albumen height, albumen length, Haugh unit, albumen index and egg shell thickness. Data were subjected to principal component analysis. Egg quality traits had three principal components (factors) that contributed 85.805% of the total variability of the original eleven egg characteristics tested. The three principal components had Eigen values of 4.73 (PC1), 3.656 (PC2) and 1.069 (PC3). The first factor (PC1) accounted for 42.84% of the total variance, the second factor (PC2) accounted for 33.24% of the total variance, while the third factor (PC3) accounted for 9.72% of the total variance. The moderate to large communalities (0.583 – 0.944) observed indicate that a large number of variance has been accounted for by the factor solution. The present principal component analysis provided a means for objective description of the interdependence in the original eleven egg quality characteristics of Isa Brown layer chickens.

Źródło:

World Scientific News; 2017, 70, 2; 304-311
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Principal Component Analysis and Cluster Analysis In Multivariate Assessment of Water Quality

Autorzy:

Jankowska, J.
Radzka, E.
Rymuza, K.

Powiązania:

https://bibliotekanauki.pl/articles/124319.pdf

Data publikacji:

2017

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

principal component analysis
water quality
cluster analysis

Opis:

This paper deals with the use of multivariate methods in drinking water analysis. During a five-year project, from 2008 to 2012, selected chemical parameters in 11 water supply networks of the Siedlce County were studied. Throughout that period drinking water was of satisfactory quality, with only iron and manganese ions exceeding the limits (21 times and 12 times, respectively). In accordance with the results of cluster analysis, all water networks were put into three groups of different water quality. A high concentration of chlorides, sulphates, and manganese and a low concentration of copper and sodium was found in the water of Group 1 supply networks. The water in Group 2 had a high concentration of copper and sodium, and a low concentration of iron and sulphates. The water from Group 3 had a low concentration of chlorides and manganese, but a high concentration of fluorides. Using principal component analysis and cluster analysis, multivariate correlation between the studied parameters was determined, helping to put water supply networks into groups according to similar water quality.

Źródło:

Journal of Ecological Engineering; 2017, 18, 2; 92-96
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

The use of some morphological traits for the assessment of genetic diversity in spinach (Spinacia oleracea L.) landraces

Autorzy:

Ebadi-Segheloo, Asghar
Asadi-Gharneh, Hossein ali
Mohebodini, Mehdi
Janmohammadi, Mohsen
Nouraein, Mojtaba
Sabaghnia, Naser

Powiązania:

https://bibliotekanauki.pl/articles/2199739.pdf

Data publikacji:

2014-06-19

Wydawca:

Instytut Hodowli i Aklimatyzacji Roślin

Tematy:

breeding
cluster analysis
diversity
landraces
principal component analysis

Opis:

Investigation of native accessions of spinach (Spinacia oleracea L.) would be aid in the development of new genetically improved varieties, so in this research 121 spinach landraces, collected from the various spinach growing areas of Iran, were evaluated to determine their diversity using several agro-morphological traits. High coefficients of variation (CV) were recorded in fresh yield, leaf area and dry yield. Using principal component (PC) analysis, the first three PCs with eigenvalues more than 0.9 contributed 80.56% of the variability among accessions. The first PC was related to leaf yield performance (fresh and dry yields, leaf numbers at flowering and lateral branches) while the PC2 was related to leaf characteristic (leaf width, petiole length, petiole diameter and leaf area). The third PC was related to seed characteristic (seed yield and 1000-seed weight) and was named as seed property component. The 121 spinach landraces were grouped into six clusters using cluster analysis. Each cluster had some specific characteristics of its own and the clusters I and II were clearly separated from clusters III and V and also from clusters IV and VI. The studied accessions are an important resource for the generation of a core collection of spinach in the world. The results of present research will support tasks of conservation and utilization of landraces in spinach breeding programs.

Źródło:

Plant Breeding and Seed Science; 2014, 69; 69-80
1429-3862
2083-599X

Pojawia się w:

Plant Breeding and Seed Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

The quality of public finance in the light of fiscal governance concept: implications for the European Union countries

Autorzy:

Kargol-Wasiluk, Aneta
Wildowicz-Giegiel, Anna

Powiązania:

https://bibliotekanauki.pl/articles/22446543.pdf

Data publikacji:

2018

Wydawca:

Instytut Badań Gospodarczych

Tematy:

public finance
quality
fiscal governance
principal component analysis

Opis:

Research background: The research area on the quality of public finance (QPF) appears to be intellectually attractive. In the light of the challenges of the 21st century, public finance should be characterized by adequate quality, ensuring effective implementation of the economic functions of government. The problem of QPF is increasingly more frequent in the face of a deteriorating fiscal situation of most countries in Europe and around the world. Hence, it is worth considering which factors determine the quality of public finance. Purpose of the article: This article aims to show the possibility of assessing the quality of public finance in the light of fiscal governance concept.  The identification of the key components of QPF seems to be useful from the point of view of empirical research, and can be implemented to assess the quality of public finance in the EU?28. Methods: Descriptive analysis along with principal component analysis (PCA) was implemented to indicate dimensions of QPF. Findings & Value added: The quality of public finance consists of a well-designed fiscal rules (numerical and non-numerical) and institutions, as well as structural reforms. The obtained results allow to characterize the quality of public finance through the prism of six identified principal components. They have a mixed character, two of them are partly or totally related to the institutional aspects of public finance, which proves their importance in the process of improving the quality of public finance. Improving the quality of public finance remains a key challenge for policy makers in the EU. The growing impact of globalization and the aging population also cause the need to improve the qualitative aspects of fiscal policy. The study contributes to the literature on public finance, particularly in the empirical dimension through broadening the knowledge on institutional factors which can be used to measure QPF index. The results of research have certainly enriched the existing knowledge on the phenomenon of QPF and the ways of its measurement.

Źródło:

Equilibrium. Quarterly Journal of Economics and Economic Policy; 2018, 13, 3; 411-426
1689-765X
2353-3293

Pojawia się w:

Equilibrium. Quarterly Journal of Economics and Economic Policy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

Geomorphic Control on Soil Erosion – a Case Study in the Subarnarekha Basin, India

Autorzy:

Kathwas, Amar Kumar
Patel, Nilanchal

Powiązania:

https://bibliotekanauki.pl/articles/2088182.pdf

Data publikacji:

2021

Wydawca:

Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej

Tematy:

geomorphological feature
soil erosion
USLE
principal component analysis

Opis:

Geomorphology depicts the qualitative and quantitative characteristics of both terrain and landscape features combined with the processes responsible for its evolution. Soil erosion by water involves processes, which removes soil particles and organic matter from the upper sheet of the soil surface, and then transports the eroded material to distant location under the action of water. Very few studies have been conducted on the nature and dynamics of soil erosion in the different geomorphologic features. In the present investigation, an attempt has been made to assess the control of geomorphologic features on the soil loss. Universal Soil Loss Equation (USLE) was used to determine soil loss from the various geomorphological landforms. Principal component analysis (PCA) was implemented on the USLE parameters to determine the degree of association between the individual principal components and the USLE-derived soil loss. Results obtained from the investigation signify the influence of the various landforms on soil erosion. PC5 is found to be significantly correlated with the USLE-derived soil loss. The results ascertained significant association between the soil loss and geomorphological landforms, and therefore, suitable strategies can be implemented to alleviate soil loss in the individual landforms.

Źródło:

Polish Journal of Soil Science; 2021, 54, 1; 1-24
0079-2985

Pojawia się w:

Polish Journal of Soil Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

The application of principal component analysis (pca) for the study of the spanish tourist demand

Autorzy:

González, María Jesús González
Pascual, María-Eva Vallejo

Powiązania:

https://bibliotekanauki.pl/articles/1051397.pdf

Data publikacji:

2018-12-30

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

Spain
autonomous communities
tourist demand
principal component analysis

Opis:

The objective of this study is the characterisation of the Spanish autonomous communities as tourist destinations for Spanish trips, based on the activities carried out, using the principal component method. The Spanish tourist is not only motivated by the sun and beach. This paper aims to clarify how Spanish people consider other tourist destinations. We contrast how frequently other types of tourism are valued when choosing their destination within the Spanish geography. Inland tourism, sports tourism, entertainment as well as gastronomy are becoming increasingly important.

Źródło:

Quaestiones Geographicae; 2018, 37, 4; 43-52
0137-477X
2081-6383

Pojawia się w:

Quaestiones Geographicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Taxonomic position of Pinus ceciliae (Pinaceae) endemic for Balearic Islands as revealed on needle characteristics

Autorzy:

Boratynska, K.
Tomaszewski, D.
Montserrat, J.M.
Marek, S.
Boratynski, A.

Powiązania:

https://bibliotekanauki.pl/articles/2077667.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Instytut Dendrologii PAN

Tematy:

biometry
discrimination analysis
Pinus halepensis
Principal Component Analysis

Opis:

The Cecilian pine (Pinus ceciliae) is endemic to Balearic islands (Spain). It is a small taxon, some- times treated as synonym of Aleppo pine (P. halepensis), to which is closely related, differing mainly with dense crown shape and upright branches. The other characteristics, which differ between P. ceciliae and P. halepensis concern the cone scale and needle length only. We examined biometrically needles of Cecilian pine from Mallorca (5 tress) and Menorca (9 trees) islands, and compared them to Aleppo pine populations rep- resented by 30 trees from each island. Each tree was represented by 5 needles, and they were studied with respect to 17 morphological and anatomical characteristics. We detected that needles of the Cecilian pine were smaller, but only when compared to the Aleppo pine from the same island. In general, this difference was also observed in the number of resin canals, number of stomata and stomatal rows. Interestingly, the proportions of the needle dimensions pattern were similar in both taxa. In conclusion we stated the results support the taxonomic rank of Cecilian pine as a variety, Pinus halepensis var. ceciliae (Llorens & L.Llorens) L.Llorens, Fl. Països Catalans, 1: 197 (1984)

Źródło:

Dendrobiology; 2019, 82; 8-16
1641-1307

Pojawia się w:

Dendrobiology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

A Water Quality Evaluation of Integrated Mangrove Aquaculture System for Water Treatment in Super-Intensive White Leg Shrimp Pond

Autorzy:

Mahmudi, Mohammad
Musa, Muhammad
Bunga, Alamanda
Wati, Nur Azlina
Arsad, Sulastri
Lusiana, Evellin Dewi

Powiązania:

https://bibliotekanauki.pl/articles/2086395.pdf

Data publikacji:

2022

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

coastal ecosystem
eco-aquaculture
pollution index
principal component

Opis:

White leg shrimp (Litopenaeus vannamei) is known as a prime aquacultural commodity in Indonesia. However, the rapid growth of shrimp farming has resulted in widespread destruction of coastal ecosystems, including mangrove swamps. Intensification of shrimp culture has led to many other environmental problems. Integration of mangroves into aquaculture systems (IMAS) should be considered as a way to preserve the mangrove ecosystem as well as sustainability of the aquaculture business by treating the influent and effluent water. This study aimed to assess the benefits of integrating mangroves into shrimp aquaculture, in terms of water quality. The results showed that temperature, dissolved oxygen (DO), and nitrite levels in the water significantly differed between sample sites. PCA analysis indicates that total organic matter (TOM), nitrates, nitrites, and ammonia were the principal factors in the overall water quality of the ponds. The highest pollution index was found in the super-intensive shrimp ponds ('moderately polluted'), while the other sites, including the mangrove area, were categorized as 'lightly polluted'. These findings suggest that the presence of mangroves may improve the quality of aquaculture wastewater, but the pollution index may still not reach the 'good' category. It is therefore recommended that a wastewater treatment plant be installed to support the integrated aquaculture system.

Źródło:

Journal of Ecological Engineering; 2022, 23, 4; 287--296
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

Spectral Mapping Using Kernel Principal Components Regression for Voice Conversion

Autorzy:

Song, P.
Zhao, L.
Bao, Y.

Powiązania:

https://bibliotekanauki.pl/articles/177529.pdf

Data publikacji:

2013

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

spectral mapping
overfitting
oversmoothing
discontinuity
kernel principal component regression

Opis:

The Gaussian mixture model (GMM) method is popular and efficient for voice conversion (VC), but it is often subject to overfitting. In this paper, the principal component regression (PCR) method is adopted for the spectral mapping between source speech and target speech, and the numbers of principal components are adjusted properly to prevent the overfitting. Then, in order to better model the nonlinear relationships between the source speech and target speech, the kernel principal component regression (KPCR) method is also proposed. Moreover, a KPCR combined with GMM method is further proposed to improve the accuracy of conversion. In addition, the discontinuity and oversmoothing problems of the traditional GMM method are also addressed. On the one hand, in order to solve the discontinuity problem, the adaptive median filter is adopted to smooth the posterior probabilities. On the other hand, the two mixture components with higher posterior probabilities for each frame are chosen for VC to reduce the oversmoothing problem. Finally, the objective and subjective experiments are carried out, and the results demonstrate that the proposed approach shows greatly better performance than the GMM method. In the objective tests, the proposed method shows lower cepstral distances and higher identification rates than the GMM method. While in the subjective tests, the proposed method obtains higher scores of preference and perceptual quality.

Źródło:

Archives of Acoustics; 2013, 38, 1; 39-45
0137-5075

Pojawia się w:

Archives of Acoustics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Quantum image classification using principal component analysis

Autorzy:

Ostaszewski, M.
Sadowski, P.
Gawron, P.

Powiązania:

https://bibliotekanauki.pl/articles/375706.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

some quantum algorithms
quantum image processing
principal component analysis

Opis:

We present a novel quantum algorithm for the classification of images. The algorithm is constructed using principal component analysis and von Neuman quantum measurements. In order to apply the algorithm we present a new quantum representation of grayscale images.

Źródło:

Theoretical and Applied Informatics; 2015, 27, 1; 1-12
1896-5334

Pojawia się w:

Theoretical and Applied Informatics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Association between dietary patterns and cardiovascular risk factors in a selected population of Lower Silesia (PURE Study Poland)

Autorzy:

Czekajlo, A.
Różańska, D.
Zatońska, K.
Szuba, A.
Regulska-Ilow, B.

Powiązania:

https://bibliotekanauki.pl/articles/2081935.pdf

Data publikacji:

2018

Wydawca:

Instytut Medycyny Wsi

Tematy:

risk factors
cardiovascular diseases
principal component analysis
dietary patterns

Opis:

Introduction. Dietary pattern analysis is used to describe the dietary habits of a selected population. In many studies, dietary patterns (DPs) have been associated with risk factors for cardiovascular disease (CVD). The aim of the study was to assess the association between dietary patterns identified in the population of Lower Silesia, Poland, with anthropometric and biochemical risk factors for CVD. Materials and method. The study group included 2,025 participants of the Prospective Urban Rural Epidemiological (PURE) Study. Dietary intake was evaluated based on data from the Food Frequency Questionnaire (FFQ). Dietary patterns were derived using principal component analysis (PCA). The relationship between DPs and body mass index (BMI), waist circumference, waist-hip ratio, blood pressure, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides and fasting glucose level, was assessed. Results. Three dietary patterns identified in the study explained 35.6% of total variance. The ‘fruit, vegetables & dairy’ DP, characterized by a high intake of vegetables, fruits, nuts, seeds, raisins, milk and low-fat dairy, was associated with improved lipid profile and anthropometric measures, lower diastolic blood pressure and lower fasting glucose concentration. ‘Traditional’ and ‘fat & sugar’ DPs were unfavourably associated with most of the risk factors for CVD presented in this study. Conclusions. Dietary patterns identified in this study were differently related to selected anthropometric and biochemical risk factors for CVD. ‘Fruit, vegetables & dairy’ DP was favourably associated with the biochemical and anthropometric CVD risk factors, and was characterized by higher nutritional value in comparison with ‘traditional’ and ‘fat & sugar’ DPs.

Źródło:

Annals of Agricultural and Environmental Medicine; 2018, 25, 4; 635-641
1232-1966

Pojawia się w:

Annals of Agricultural and Environmental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Wavelength-sensitive-function-based spectral reconstruction using segmented principal component analysis

Autorzy:

Wu, G.
Shen, X.
Liu, Z.
Zhang, J.

Powiązania:

https://bibliotekanauki.pl/articles/174199.pdf

Data publikacji:

2016

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

spectral reconstruction
wavelength-sensitive function
segmented principal component analysis

Opis:

Spectral images provide richer information than colorimetric images. A high-dimensional spectral data presents a challenge for efficient spectral reconstruction. In conventional reconstruction methods it is very difficult to obtain good spectral and colorimetric accuracy simultaneously. In this paper, a segmented principal component analysis (SPCA) method and a weighted segmented principal component analysis (wSPCA) method are proposed for efficient reconstruction of spectral color information. The methods require, firstly, partitioning the complete spectrum of wavelengths into two subgroups, considering the sensitivity of human visual system. Then the classical principal component analysis (PCA) carried out each subgroup of data separately. The results indicated that the spectral and colorimetric accuracy of the SPCA and wSPCA outperformed the PCA and weighted PCA, and wSPCA clearly retained more color visual information.

Źródło:

Optica Applicata; 2016, 46, 3; 365-374
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Principal component data processing in radon metrology

Autorzy:

Machaj, B.
Urbański, P.

Powiązania:

https://bibliotekanauki.pl/articles/147140.pdf

Data publikacji:

2002

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

principal component regression (PCR)
radon daughters measurement
radon measurement

Opis:

A gauge for the measurement of radon and radon daughters concentration was tested in a radon chamber. Count rate distribution in time at the output of radiation detectors was measured and registered. The count rate distribution in time was then processed employing Principal Component Analysis (PCA) and the Root Mean Square Error (RMSE) of the count rate was investigated. It was found that PCA processing removes great part of count rate random fluctuations originating from radiation statistics, which is resulting in a decrease of the count rate random error and in random error of concentration. The RMSE of radon daughters concentration is about 3 times lower when "raw" results are PCA processed. Such decrease of error, without PCA signal processing, would require 9 times higher air flow through the air filter on which the radon daughters are deposited. In case of the measurements of the radon concentration the drop of the error is 2-3 times higher in case of long counting time.

Źródło:

Nukleonika; 2002, 47, 1; 39-42
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Multi-trait evaluation of value for cultivation and use of early maturing edible potato cultivars registered in Poland

Autorzy:

Rymuza, K.

Powiązania:

https://bibliotekanauki.pl/articles/123780.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

edible potato
potato cultivar
principal component analysis
cluster analysis

Opis:

The work presents an analysis of diversity and comparison of value for cultivation and use of early maturing potato cultivars registered with the Polish National Register of Cultivars. The comparison was based on 17 yield and appearance traits and quality attributes of tubers as well as their resistance to diseases. The analysis employed the following multi-dimensional statistical methods: principal component analysis and cluster analysis. The principal component analysis revealed that over 70% of the total variation was associated with the first 6 principal components. Cluster analysis yielded 4 groups of genotypes. The first group consisted of the cultivars which produced tubers with the most shallow eyes, the best flavour and the least severe darkening of raw flesh. The cultivars in the second group produced high yields and were low in starch, dry matter and glycoalkaloids. The tubers of cultivars which were classified into the third group had the highest starch, dry matter and vitamin C contents. However, they produced the lowest yields and were quite susceptible to most diseases. The fourth group was made up of high-yielding cultivars which tended to accumulate glycoalkaloids but were most resistant to hollow heart in tubers.

Źródło:

Journal of Ecological Engineering; 2015, 16, 1; 50-56
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Optimal Stock Portfolio – Application of Multivariate Statistical Analysis
Optymalny portfel akcji – zastosowanie wielowymiarowej analizy statystycznej

Autorzy:

Konarzewska, Iwona

Powiązania:

https://bibliotekanauki.pl/articles/904809.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego

Tematy:

optimal portfolio models
principal component analysis of rates of return

Opis:

Investigating relationship between risk of the Markowitz optimal portfolio and the strength of interdependence for the set of rates of return for portfolio components we state (Konarzewska, 2008, 2012) that the risk measured as variance/standard deviation is slightly sensitive on small disturbance in data set when the series of data are strongly interrelated. What more, portfolio risk rises as the strength of interdependence declines. We have found that if strong linear relationship is present among series, it is important to control the direction between the portfolio weights vector and the eigenvector corresponding to maximal eigenvalue of the correlation/covariance matrix – the ideal situation being orthogonality of the two vectors. These results can be utilized in: the algorithm for pre-selection of investment portfolio components, construction of the optimal investment portfolio models. Both propositions utilize eigenvalue decomposition of the rates of return correlation or covariance matrix. Theoretical results are illustrated by empirical examples for medium-sized firms being components of mWIG40 index on Stock Exchange in Warsaw. We compare optimal portfolios obtained for Markowitz and PCA – aided models.
W artykule przedstawiamy wybrane wyniki teoretyczne na temat konstrukcji optymalnego portfela akcji z wykorzystaniem informacji dostepnej w wyniku przeprowadzenia analizy głównych składowych macierzy kowariancji czy też macierzy korelacji stóp zwrotu z akcji. Wyniki teoretyczne prowadzą do konstrukcji modeli optymalizacyjnych uwzględniajacych redukcję przestrzeni danych do określonej liczby głównych składowych, co udaje się skutecznie przeprowadzić w warunkach silnych związków o charakterze liniowym między szeregami stóp zwrotu z akcji. W pracy prezentujemy wyniki analiz dla modeli Markowitza oraz modeli opartych o analizę głównych składowych na przykładzie sektora średnich spółek na GPW w Warszawie w latach 2009-2011. Badanie empiryczne pokazuje różnice wyników optymalizacji oraz ryzyka portfeli w przypadkach, kiedy korzystamy z macierzy kowariancji albo korelacji.

Źródło:

Acta Universitatis Lodziensis. Folia Oeconomica; 2013, 286
0208-6018
2353-7663

Pojawia się w:

Acta Universitatis Lodziensis. Folia Oeconomica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Physicochemical characterization of synclinal spring water of Taoura, region of Souk Ahras – North East Algeria

Autorzy:

Bouhafs, Fatma
Laraba, Abdelaziz

Powiązania:

https://bibliotekanauki.pl/articles/1841971.pdf

Data publikacji:

2021

Wydawca:

Instytut Technologiczno-Przyrodniczy

Tematy:

chemistry
principal component analysis
PCA
pollution
springs
Taoura
water quality

Opis:

The springs of the Taoura region flow from a syncline shaped structure. All resources in the region were mobilized as a result of increased demand. However, the development of anthropic activities and population growth in the area pose risk for groundwater. Analytical results obtained from a series of samplings in November 2017–April 2018, express the quality of water suitable for the irrigation of agricultural land. The highest values are recorded in April 2018 at 20.5 to 21.6°C and pH of 8.0 to 8.2. The study recorded high electrical conductivity from 1390 to 1495 μS∙cm–1 and TDS from 1270 to 1500 mg∙dm–3 in November 2017, which shows important mineralization that characterizes spring water. Physical parameters were measured in situ using a HORIBA multi-parameter probe. Chemical analyses were carried out using NFT 90-005 titration, and nitrogen parameters by DIN 38405-D92 spectrophotometry. Maximum levels of nitrates and phosphates were recorded at 228 and 18.4 mg∙dm–3 respectively. The principal component analysis (PCA) showed a good correlation of the November 2017 period with mineralization parameters. Moreover, there is a strong correlation between the wet period and pollution factors. The two methods of analysis has allowed to distinguish three groups of geochemical water types: a bicarbonate calcium group typical for waters having transited in carbonate horizons. A second chloride calcium group shows basic exchange between water and clay levels, and the third chloride bicarbonate calcium group reveals an enrichment in calcium and chloride, which reflects water circulation with an exchange of the carbonated and evaporitic sedimentary rock matrix.

Źródło:

Journal of Water and Land Development; 2021, 50; 27-37
1429-7426
2083-4535

Pojawia się w:

Journal of Water and Land Development

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Electronic noses for monitoring benzene occupational exposure in biological samples of Egyptian workers

Autorzy:

Mohamed, Ehab I.
Khalil, Gihane I.
Abdel-Mageed, Samir M.
Bayoumi, Amani M.
Ramadan, Heba S.
Kotb, Metwally A.

Powiązania:

https://bibliotekanauki.pl/articles/2179801.pdf

Data publikacji:

2013-03-01

Wydawca:

Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi

Tematy:

phenol
muconic acid
exhaled air
blood
urine
principal component analysis

Opis:

Objectives: Benzene is commonly emitted in several industries, leading to widespread environmental and occupational exposure hazards. While less toxic solvents have been substituted for benzene, it is still a component of petroleum products and is a trace impurity in industrial products resulting in continued higher occupational exposures in industrial settings in developing countries. Materials and Methods: We investigated the potential use of an electronic nose (e-nose) to monitor the headspace volatiles in biological samples from benzene-exposed Egyptian workers and non-exposed controls. The study population comprised 150 non-smoking male workers exposed to benzene and an equal number of matching non-exposed controls. We determined biomarkers of benzene used to estimate exposure and risk including: benzene in exhaled air and blood; and its urinary metabolites such as phenol and muconic acid using gas chromatography technique and a portable e-nose. Results: The average benzene concentration measured in the ambient air of the workplace of all studied industrial settings in Alexandria, Egypt; was 97.56±88.12 μg/m³ (range: 4.69–260.86 μg/m³). Levels of phenol and muconic acid were signifi cantly (p < 0.001) higher in both blood and urine of benzene-exposed workers as compared to non-exposed controls. Conclusions: The e-nose technology has successfully classifi ed and distinguished benzene-exposed workers from non-exposed controls for all measured samples of blood, urine and the exhaled air with a very high degree of precision. Thus, it will be a very useful tool for the low-cost mass screening and early detection of health hazards associated with the exposure to benzene in the industry.

Źródło:

International Journal of Occupational Medicine and Environmental Health; 2013, 26, 1; 165-172
1232-1087
1896-494X

Pojawia się w:

International Journal of Occupational Medicine and Environmental Health

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

A game theoretical study of generalised trust and reciprocation in Poland. [Part] 2, A description of the study group

Autorzy:

Markowska-Przybyła, U.
Ramsey, D. M.

Powiązania:

https://bibliotekanauki.pl/articles/406286.pdf

Data publikacji:

2015

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

Bayesian networks
principal component analysis
social survey
experimental game theory

Opis:

The first article describing this project presented the three games that the participants played: the Ultimatum Game, the Trust Game and the Public Goods Game. This article describes the study group on the basis of a questionnaire regarding where they study and come from, their social contacts, interest in current issues, views on inequality and outlook on life. A description of the migratory decisions of students is given. In particular, two exploratory methods are used to investigate the data’s structure: Bayesian networks and principal component analysis. Bayesian networks are used to illustrate the associations between categorical variables. Principal component analysis is designed to describe latent variables which reflect the associations between numerical variables. We present the results of this analysis and discuss the advantages and disadvantages of these two methods.

Źródło:

Operations Research and Decisions; 2015, 25, 2; 51-73
2081-8858
2391-6060

Pojawia się w:

Operations Research and Decisions

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Unemployment rate for various countries since 2005 to 2012: comparison of its level and pace using functional principal component analysis

Autorzy:

Jaworski, Stanisław
Furmańczyk, Konrad

Powiązania:

https://bibliotekanauki.pl/articles/453714.pdf

Data publikacji:

2012

Wydawca:

Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki

Tematy:

B-splines basis system
functional principal component analysis,
unemployment rate

Opis:

We apply the functional principal component analysis to compare the unemployment rate in euro area, Japan and USA since 2005 to 2012. For preprocessing analysis we used B-splines system with roughness penalty for smoothing the data. The analysis enables to reveal the most important type of variation in unemployment rate and its pace's in examined countries.

Źródło:

Metody Ilościowe w Badaniach Ekonomicznych; 2012, 13, 2; 40-47
2082-792X

Pojawia się w:

Metody Ilościowe w Badaniach Ekonomicznych

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

THE INS AND OUTS OF UNEMPLOYMENT IN POLISH VOIVODESHIPS

Autorzy:

Jaworski, Stanisław

Powiązania:

https://bibliotekanauki.pl/articles/453208.pdf

Data publikacji:

2014

Wydawca:

Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki

Tematy:

unemployment rate
Poisson process
smoothing
functional principal component data analysis

Opis:

This paper measures and compares the job-finding and separation transition rates of Polish voivodeships from 2005:Q1 to 2014:Q2. It uses readily accessible data of Local Data Bank in Poland: registered unemployment person by duration of unemployment and registered unemployment rate. The method of measurement stems from influential paper by Shimer on "Reassesing the Ins and Outs of Unemployment". The main sources of variability between the rates are investigated in terms of functional principal components.

Źródło:

Metody Ilościowe w Badaniach Ekonomicznych; 2014, 15, 2; 349-358
2082-792X

Pojawia się w:

Metody Ilościowe w Badaniach Ekonomicznych

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Alarms management by supervisory control and data acquisition system for wind turbines

Autorzy:

Ramirez, Isaac Segovia
Mohammadi-Ivatloob, Behnam
Márqueza, Fausto Pedro García

Powiązania:

https://bibliotekanauki.pl/articles/1841786.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

alarm management
maintenance management
principal component analysis
SCADA
wind turbines

Opis:

Wind energy is one of the most relevant renewable energy. A proper wind turbine maintenance management is required to ensure continuous operation and optimized maintenance costs. Larger wind turbines are being installed and they require new monitoring systems to ensure optimization, reliability and availability. Advanced analytics are employed to analyze the data and reduce false alarms, avoiding unplanned downtimes and increasing costs. Supervisory control and data acquisition system determines the condition of the wind turbine providing large dataset with different signals and alarms. This paper presents a new approach combining statistical analysis and advanced algorithm for signal processing, fault detection and diagnosis. Principal component analysis and artificial neural networks are employed to evaluate the signals and detect the alarm activation pattern. The dataset has been reduced by 93% and the performance of the neural network is incremented by 1000% in comparison with the performance of original dataset without filtering process.

Źródło:

Eksploatacja i Niezawodność; 2021, 23, 1; 110-116
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Differences between technological and textural parameters of meat from farmed and wildlife red deer (Cervus elaphus) determined by PCA method
Różnice pomiędzy parametrami technologicznymi i teksturalnymi mięsa jeleni (Cervus elaphus) hodowlanych i dziko żyjących określone metodą składowych głównych

Autorzy:

Kral, M.
Snirc, M.
Tremlova, B.

Powiązania:

https://bibliotekanauki.pl/articles/825883.pdf

Data publikacji:

2018

Wydawca:

Polskie Towarzystwo Technologów Żywności

Tematy:

farmed deer
wildlife animal
red deer
Cervus elaphus
meat
difference
technological parameter
texture parameter
determination
PCA method zob.principal component analysis
principal component analysis

Źródło:

Żywność Nauka Technologia Jakość; 2018, 25, 3
1425-6959

Pojawia się w:

Żywność Nauka Technologia Jakość

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

A comparative analysis of the principal component method and parallel analysis in working with official statistical data

Autorzy:

Holubova, Halyna

Powiązania:

https://bibliotekanauki.pl/articles/10559806.pdf

Data publikacji:

2023-02-24

Wydawca:

Główny Urząd Statystyczny

Tematy:

principal components
principal component analysis
factor analysis
Kaiser criterion
рarallel analysis
simulation

Opis:

The dynamic development of the digitized society generates large-scale information data flows. Therefore, data need to be compressed in a way allowing its content to remain complete and informative. In order for the above to be achieved, it is advisable to use the principal component method whose main task is to reduce the dimension of multidimensional space with a minimal loss of information. The article describes the basic conceptual approaches to the definition of principle components. Moreover, the methodological principles of selecting the main components are presented. Among the many ways to select principle components, the easiest way is selecting the first k-number of components with the largest eigenvalues or to determine the percentage of the total variance explained by each component. Many statistical data packages often use the Kaiser method for this purpose. However, this method fails to take into account the fact that when dealing with random data (noise), it is possible to identify components with eigenvalues greater than one, or in other words, to select redundant components. We conclude that when selecting the main components, the classical mechanisms should be used with caution. The Parallel analysis method uses multiple data simulations to overcome the problem of random errors. This method assumes that the components of real data must have greater eigenvalues than the parallel components derived from simulated data which have the same sample size and design, variance and number of variables. A comparative analysis of the eigenvalues was performed by means of two methods: the Kaiser criterion and the parallel Horn analysis on the example of several data sets. The study shows that the method of parallel analysis produces more valid results with actual data sets. We believe that the main advantage of Parallel analysis is its ability to model the process of selecting the required number of main components by determining the point at which they cannot be distinguished from those generated by simulated noise.

Źródło:

Statistics in Transition new series; 2023, 24, 1; 199-212
1234-7655

Pojawia się w:

Statistics in Transition new series

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

A new method for detecting cross-inhibition effects in the environmental biocatalytic processes

Autorzy:

Herke, Z.
Maskow, T.
Nemeth, Z.I.

Powiązania:

https://bibliotekanauki.pl/articles/80851.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

biocatalysis
microorganism
enzyme
bioremediation
inhibition
modelling
regression analysis
principal component analysis

Źródło:

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2015, 96, 4
0860-7796

Pojawia się w:

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Elucidation of tidal spatial-temporal variation of physico-chemical and nutrient parameters of estuarine water at South Gujarat

Autorzy:

Desai, Nisheeth C.
Kukadiya, Nipul B.
Mehta1, Jignasu P.
Godhani, Dinesh R.
Lakhmapurkar, Jayendra
Dave, Bharti P.

Powiązania:

https://bibliotekanauki.pl/articles/1030123.pdf

Data publikacji:

2020

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Estuary water
Nutrients
Physico-chemical parameters
Principal component analysis
Tidal variation

Opis:

In the present study, the four estuaries were selected from the South Gujarat region to appraise the impact of industrial pollution in the estuarine water samples. The study focused on the tidal variation of nutrients, which disclosed that concentrations of NO2–N, NO3–N, NH4–N, TN, and reactive silicates were higher in low-tide whereas pH, salinity, and dissolved oxygen were higher in high-tide water samples. The results of high BOD and low DO expose the anthropogenic inputs in these estuaries during the low-tide. The results of physico-chemical and nutrients parameters of water showed that the pollution level is strongly influenced by tidal and seasonal changes. Pearson’s correlation matrix and principal component analysis (PCA) are applied to a hydrological and hydrographical dataset for finding the spatial-temporal variation during the tidal difference. This study suggested that there is an impact of industrial pollution and anthropogenic inputs on the estuarine water of the study area.

Źródło:

World Scientific News; 2020, 143; 79-102
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Wavelets and principal component analysis method for vibration monitoring of rotating machinery

Autorzy:

Bendjama, H.
Boucherit, M. S.

Powiązania:

https://bibliotekanauki.pl/articles/949212.pdf

Data publikacji:

2016

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

vibration
fault diagnosis
wavelet analysis
principal component analysis, squared
prediction error

Opis:

Fault diagnosis is playing today a crucial role in industrial systems. To improve reliability, safety and efficiency advanced monitoring methods have become increasingly important for many systems. The vibration analysis method is essential in improving condition monitoring and fault diagnosis of rotating machinery. Effective utilization of vibration signals depends upon effectiveness of applied signal processing techniques. In this paper, fault diagnosis is performed using a combination between Wavelet Transform (WT) and Principal Component Analysis (PCA). The WT is employed to decompose the vibration signal of measurements data in different frequency bands. The obtained decomposition levels are used as the input to the PCA method for fault identification using, respectively, the Q-statistic, also called Squared Prediction Error (SPE) and the Q-contribution. Clearly, useful information about the fault can be contained in some levels of wavelet decomposition. For this purpose, the Q-contribution is used as an evaluation criterion to select the optimal level, which contains the maximum information.Associated to spectral analysis and envelope analysis, it allows clear visualization of fault frequencies. The objective of this method is to obtain the information contained in the measured data. The monitoring results using real sensor measurements from a pilot scale are presented and discussed.

Źródło:

Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 659-670
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Trace elements in scalp hair of leukaemia patients

Autorzy:

Khuder, A.
Bakir, M. A.
Hasan, R.
Mohammad, A.
Habil, K.

Powiązania:

https://bibliotekanauki.pl/articles/971518.pdf

Data publikacji:

2014

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

leukaemia
principal component analysis
scalp hair
U-test
X-ray fluorescence

Opis:

The aim of this study was to determine the concentration of Fe, Ni, Cu, Zn and Pb in scalp hair of leukaemia patients and healthy volunteers, using the optimised XRF method. Leukaemia hair samples were classifi ed corresponding to type, growth and age of the participants. The results showed that the studied trace elements (TEs) in both of leukaemia and control groups were positively skewed. In comparison with the control group, lower Fe, Cu, Zn and Pb and higher of Ni medians were found in all studied leukaemia patients. The median rank obtained by Mann–Whitney U-test revealed insignifi cant differences between the leukaemia patients subgroups and the controls. An exact probability (α < 0.05) associated with the U-test showed signifi cant differences between medians in leukaemia patients and controls groups for Pb (lymphatic/control, acute/control), Cu (lymphatic/control, chronic/control), Ni (lymphatic/control, chronic/control) and Fe (chronic/control). Very strong positive and negative correlations (r > 0.70) in the scalp hair of control group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn, Pb/Fe-Pb, Cu/Ni-Zn/Ni, Cu/Ni-Pb/Ni, Zn/Ni-Pb/Ni, Zn/Fe-Zn/Cu, Pb/Ni-Ni and Ni/Fe-Pb/Ni, whereas only very strong positive ratios in the scalp hair of leukaemia patients group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn and Pb/Fe-Pb, all correlations were signifi cant at p < 0.05. Other strong and signifi cant correlations were also observed in scalp hair of both groups. Signifi cant differences between grouping of studied TEs in all classifi ed leukaemia groups and controls were found using principal component analysis (PCA). The results of PCA confi rmed that the type and the growth of leukaemia factors were more important in element loading than the age factor.

Źródło:

Nukleonika; 2014, 59, 3; 111-120
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

Factors of the development of organic farming in Poland at the voivodship level

Autorzy:

Nowak, Ewa
Jadczyszyn, Jan

Powiązania:

https://bibliotekanauki.pl/articles/2148092.pdf

Data publikacji:

2020-12-30

Wydawca:

Instytut Uprawy Nawożenia i Gleboznawstwa – Państwowy Instytut Badawczy

Tematy:

organic farming
Rural Development Program
Principal component analysis – PCA
voivodships
Polska

Opis:

The purpose of the research based on the data from the Report on the state of organic farming in Poland in 2015–2016 and environmental conditions, was to determine the impact of natural and economic factors and subsidies from EU programs on the level of organic production and to better understand the diver-sity of the spatial structure of organic farming within the system of provinces (voivodships). Nineteen structural, socio-economic and financial features, and 3 environmental features that charac-terize the quality of agricultural production and forms of nature protection for 16 voivodships, were used as assessment criteria.Principal component analysis allowed the basic factors of diver-sification to be discovered of the set of voivodships contained in the hidden structure defined by the features adopted for analysis. Homogeneous groups – organic farming types by voivodships were distinguished using the k-means method.The comparative analysis allowed the connections between the structure of organic farming and its place in voivodships to be highlighted in connection with support for organic farming, the number of producers of organic agricultural products, production of feed on arable land, production of cereals and vegetables. The location of organic farms is related to the occurrence of Natura 2000 areas. The first type includes two voivodships, Zachodnio-pomorskie and Warmińsko-Mazurskie – with the highest level of development of organic farming. In the second type, the fol-lowing voivodships were concentrated: Lubelskie, Łódzkie, Ma-zowieckie, Podlaskie and Świętokrzyskie, with a high level of or-ganic farming, where farms smaller in area, that focus on fruit and vegetable production are the predominant type. In the third type, the following voivodships were located in the region of western Poland: Pomorskie and Wielkopolskie with a medium level of organic farming and very diverse in characteristics, including the largest and smaller organic farms with a low level of fruit and vegetable production. The fourth type includes the Małopolskie and Podkarpackie voivodships with a very small farm area and a small number of producers. In the fifth type with the least developed organic farming with a small number of producers and low fruit and vegetable production, three voivodships focused on the average farm area: Śląskie, Opolskie and Kujawsko-Pomorskie.

Źródło:

Polish Journal of Agronomy; 2020, 43; 43-46
2081-2787

Pojawia się w:

Polish Journal of Agronomy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Fault diagnosis of rotating machines using vibration and bearing temperature measurements

Autorzy:

Nembhard, A. D.
Sinha, J. K.
Pinkerton, A. J.
Elbhbah, K.

Powiązania:

https://bibliotekanauki.pl/articles/328481.pdf

Data publikacji:

2013

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

vibration monitoring
condition monitoring
rotating machinery
fault diagnosis
principal component analysis

Opis:

Acquisition and subsequent processing of vibration data for fault diagnosis of rotating machinery with multiple bearings, such as Turbo-generator (TG) sets, can be quite involved, as data are usually required in three mutually perpendicular directions for reliable diagnosis. Consequently, the task of diagnosing faults on such systems may be daunting for even an experienced analyst. Hence, the current study aims to develop a simplified fault diagnosis (FD) method that uses just a single vibration and a single temperature sensor on each bearing. Initial trials on an experimental rotating rig indicate that supplementing vibration data with temperature measurements gave improved FD when compared with FD using vibration data alone. Observations made from the initial trials are presented in this paper.

Źródło:

Diagnostyka; 2013, 14, 3; 45-51
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Adult Participation in Evening Secondary Schools: The Findings of Empirical Research in the Greek Islands

Autorzy:

Papadimitriou, Achilleas

Powiązania:

https://bibliotekanauki.pl/articles/28409259.pdf

Data publikacji:

2023

Wydawca:

Uniwersytet Dolnośląski DSW. Wydawnictwo Naukowe DSW

Tematy:

adult participation
evening schools
Greek islands
quantitative research
principal component analysis

Opis:

The study of adult participation in education and the examination of the factors that influence their final decision is one of the most critical issues in the field. This article summarises the findings of empirical research on adult engagement in evening schools in Greece, with an emphasis on evening schools in the Greek islands. Evening schools started in Greece around 60 years ago. These schools, now part of the secondary education system, are primarily aimed towards those who work during the day (mostly adults). Their goal is to provide the opportunity for adults who, for some reason, interrupted their studies in Gymnasium (lower secondary/middle school) or Lyceum (upper secondary/high school) to complete it. There has never been a study on residents of Greek islands who participate in educational programmes of this nature. The presented research investigates factors that impact adult participation in all evening schools administratively situated in Greek islands. Between February and May 2022, 268 adult students participated in the study by completing a survey questionnaire that was quantitatively evaluated using SPSSs. The sample comes from all the islands where evening Lyceums operate. To determine the elements that influence participation, the data was submitted to component analysis using the Principal Component Analysis (PCA) approach. Four of the discovered factors are deemed critical (self-assessment, attitudes towards education, educational perspective and expectations), while others seem somewhat relevant and have a role.

Źródło:

Teraźniejszość – Człowiek – Edukacja; 2023, 25, 1(93); 9-32
1505-8808
2450-3428

Pojawia się w:

Teraźniejszość – Człowiek – Edukacja

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

Analysis of modern methods for increasing and managing the financial prosperity of businesses in the context of performance: a case study of the tourism sector in Slovakia

Autorzy:

Onuferová, Erika
Čabinová, Veronika
Dzurov Vargová, Tünde

Powiązania:

https://bibliotekanauki.pl/articles/19233492.pdf

Data publikacji:

2020

Wydawca:

Instytut Badań Gospodarczych

Tematy:

business performance
modern methods
performance benchmarking
travel agencies
Principal Component Analysis

Opis:

Research background: In the context of constantly changing business environment, the financial sector is focusing on new trends in financial management systems. Nowadays, there is a need to achieve long-term financial growth, so financial managers try to develop new models for managing and improving the financial performance of businesses in economic practice. Purpose of the article: This article aims to determine the financial performance of travel agencies by applying modern business performance evaluation methods in order to create a performance portfolio (ranking) for the years 2013-2017, subsequently to reveal the concordance rate of order of the selected business entities by comparing applied financial methods in the context of performance benchmarking. The research question is as follows: Does the multidimensional PCA method in the form of the performance portfolio of travel agencies provide similar financial results compared to the EVA indicator? Methods: For measuring the financial performance of businesses, the method of Principal Component Analysis (PCA) and the indicator Economic Value Added (EVA) were chosen. Spearman's rank-order correlation was applied in order to reveal the concordance rate of the analyzed travel agencies. Findings & Value added: The results indicate that by applying the PCA method, 6 key performance factors can be identified. Moreover, the findings revealed that the assessment of travel agencies using the PCA method and EVA indicator did not lead to the same financial results. Individual financial methods identified a different number of strong-performing and inefficient business entities. In this backdrop, we concluded that the business performance measurement based on the PCA method is not a suitable alternative to measuring performance using the EVA indicator.

Źródło:

Oeconomia Copernicana; 2020, 11, 1; 95-116
2083-1277

Pojawia się w:

Oeconomia Copernicana

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Forecasting of subjective comfort in tram using ordinal logistic regression and manifold learning

Autorzy:

Pietraszek, J.
Grzegożek, W.
Szczygieł, J.

Powiązania:

https://bibliotekanauki.pl/articles/246634.pdf

Data publikacji:

2012

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

rail transport
vibrations
ordinal logistic regression
principal component analysis
manifold learning

Opis:

Comfort in a vehicle has a very important role to play as one of the most important dynamic performance characteristics of rail vehicles. It is the factor of ever-increasing importance, even creating a specialized branch of engineering associated with relation between human limitations and designing of machines: human–factors engineering. The vibration is known to be a major factor that affects and deteriorates ride comfort. For evaluating ride comfort in rail vehicles, there have been developed methods resulting in the creation of many standards and multiple criteria used and even standardized in different countries. One of the authors, J. Szczygieł designed and performed a passive experiment to collect data describing physical conditions of ride and associated subjective assessments of comfort. Panel of fourteen people during the tram ride made synchronous subjective assessments of comfort, assessing it on a discrete ordinal scale of 0 to 5, using electronic panels connected to the computer. At the same time computer through sensors recorded values of acceleration in three perpendicular axes. It made possible to correlate the fuzzy subjective evaluations with objective physical measurements. Because of the discrete type of fuzzy ratings of comfort, natural way of modelling is the ordinal logistic regression. The classic form of the ordinal logistic regression assumes that in the space of explanatory factors there are parallel activation hyper-planes slightly disturbed by unknown or uncontrolled noise factors. In fact, the assumption of linearity is a very strong idealization and leads to considerable misclassifications. The original space of explanatory factors is 11-dimensional with ten continuous dimensions and one discrete. Then the multivariate method, principal component analysis (PCA), was used to identify principal components, which are responsible most to the variability of the studied set. The scree plot was used to identify the number of significant PCA factors. The use of PCA revealed that the area occupied by the data set is approximately 6-dimensional. However, the dimensionality reduction of explanatory variables set did not lead to better forecasting accuracy. A more subtle analysis involving discretization techniques showed that activation hyperplanes are highly curved in the six-dimensional area identified by PCA but their dimensionality is much lower. The details of the procedure are described in the article. The article conclusion is that is necessary to introduce curvilinear coordinate system embedded into the shapes of activation hyper-planes to obtain better classification.

Źródło:

Journal of KONES; 2012, 19, 2; 403-409
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Application of evaluation algorithm for port logistics park based on PCA-SVM model

Autorzy:

Hu, B.

Powiązania:

https://bibliotekanauki.pl/articles/260528.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

port logistics demand
support vector machine
principal component analysis
economic hinterland

Opis:

To predict the logistics needs of the port, an evaluation algorithm for the port logistics park based on the PCASVM model was proposed. First, a quantitative indicator set for port logistics demand analysis was established. Then, based on the grey correlation analysis method, the specific indicator set of port logistics demand analysis was selected. The advantages of both principal component analysis and support vector machine algorithms were combined. The PCA-SVM model was constructed as a predictive model of the port logistics demand scale. The empirical analysis was conducted. Finally, from the perspective of the structure, demand, flow pattern and scale of port logistics demand, the future logistics demand of Shenzhen port was analysed. Through sensitivity analysis, the main influencing factors were found out, and the future development proposals of Shenzhen port were put forward. The results showed that the port throughput of Shenzhen City in 2016 was 21,328,200 tons. Compared with the previous year, it decreased by about 1.74 %. In summary, the PCA-SVM model accurately predicts the logistics needs of the port.

Źródło:

Polish Maritime Research; 2018, S 3; 29-35
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Multivariate and Geostatistical Analyses of Groundwater Quality for Acid Rock Drainage at Waste Rock and Tailings Storage Site

Autorzy:

Adadzi, Patrick
Allwright, Amy
Fourie, Francois

Powiązania:

https://bibliotekanauki.pl/articles/2202307.pdf

Data publikacji:

2022

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

acid rock drainage
groundwater
correlation matrix
principal component analysis
geostatistical analysis

Opis:

A multi-disciplinary approach is indispensable for adequate acid rock drainage (ARD), mineral leaching impact, and groundwater management. Groundwater is a valuable resource, and it is critical to protect as well as mitigate the effects of pollution such as ARD in the mining environment. Mine waste storage facilities (waste rocks and tailings) are potential ARD sources capable of degrading groundwater reserves. This research investigated and reported the application of a case study of multivariate statistical and spatial variability of selected parameters associated with ARD in groundwater around WRD and TSF at mine sites. Water quality analysis data of seventy water samples from 10 boreholes located at the WRD and TSF mine were utilised in this study. The correlation matrix and principal components analysis was applied to the data set to determine the associated variability in groundwater in relation to ARD. Geostatistical analysis was used to produce contour maps to ARD principal components of the study site, using ordinary kriging of the best fit models. The application of multivariate statistical and geospatial analysis in groundwater quality assessment with coupled soil and groundwater modelling of flow and transport at waste rock dump and tailings storage sites provides an essential tool for exploratory data analysis, and spatial extent determination of the relationship between various data sets significant to acid rock drainage.

Źródło:

Journal of Ecological Engineering; 2022, 23, 12; 203--216
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Interrelationship and Determining Factors of Water Quality Dynamics in Whiteleg Shrimp Ponds in Tropical Eco-Green Aquaculture System

Autorzy:

Musa, Muhammad
Mahmudi, Mohammad
Arsad, Sulastri
Lusiana, Evellin Dewi
Sunadji
Wardana, Wisnu Angga
Ompusunggu, Magdalena Florensia
Damayanti, Dhea Novita

Powiązania:

https://bibliotekanauki.pl/articles/2202326.pdf

Data publikacji:

2023

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

aquaculture wastewater
intensive system
Litopenaeus vannamei
mangrove
PCA
principal component analysis

Opis:

Whiteleg shrimp (Litopenaeus vannamei) farming is a major activity in the coastal areas of many tropical countries. To meet the demand in this market, the culture system has expanded using intensive technology, which has resulted in the emission of effluents that threaten the surrounding aquatic ecosystem. Therefore, proper aquaculture management is needed to ensure both economic and ecological benefits. This led to the emergence of eco-green aquaculture. Water quality monitoring is a critical part of aquaculture management and when performed regularly, it yields a large and complex dataset. In this study, the authors aimed to analyse the dynamics of water quality characteristics and the relationships between these variables in whiteleg shrimp ponds in a tropical eco-green aquaculture system from 2020 to 2022. Since the data includes nine parameters and is quite complex, the principal component analysis (PCA) approach was used. This method enables to identify the factors that determine water quality, which will help ensure effective and efficient aquaculture management. Consequently, the water quality variables in the studied area were reduced to five dimensions and salinity, ammonia, and pH were found to be the key factors responsible for the changes in water quality characteristics. Hence, these variables should be the focus of farming management systems.

Źródło:

Journal of Ecological Engineering; 2023, 24, 1; 19--27
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Intelligent Prediction Model of the Thermal and Moisture Comfort of the Skin-Tight Garment

Autorzy:

Cheng, Pengpeng
Wang, Jianping
Zeng, Xianyi
Bruniaux, Pascal
Chen, Daoling

Powiązania:

https://bibliotekanauki.pl/articles/2056304.pdf

Data publikacji:

2022

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych

Tematy:

sportswear tights
thermal comfort
moisture comfort
principal component analysis
intelligent prediction model

Opis:

In order to improve the efficiency and accuracy of predicting the thermal and moisture comfort of skin-tight clothing (also called skin-tight underwear), principal component analysis (PCA) is used to reduce the dimensions of related variables and eliminate the multicollinearity relationship among variables. Then, the optimized variables are used as the input parameters of the coupled intelligent model of the genetic algorithm (GA) and back propagation (BP) neural network, and the thermal and moisture comfort of different tights (tight tops and tight trousers) under different sports conditions is analysed. At the same time, in order to verify the superiority of the genetic algorithm and BP neural network intelligent model, the prediction results of GA-BP, PCA-BP and BP are compared with this model. The results show that principal component analysis (PCA) improves the accuracy and adaptability of the GA-BP neural network in predicting thermal and humidity comfort. The forecasting effect of the PCA-GA-BP neural network is obviously better than that of the GA-BP, PCA-BP, BP model, which can accurately predict the thermal and moisture comfort of tight-fitting sportswear. The model has better forecasting accuracy and a simpler structure.

Źródło:

Fibres & Textiles in Eastern Europe; 2022, 1 (151); 50--58
1230-3666
2300-7354

Pojawia się w:

Fibres & Textiles in Eastern Europe

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

An identification source of variation on the water quality pattern in the Malacca River basin using chemometric approach

Autorzy:

Hua, A. K.

Powiązania:

https://bibliotekanauki.pl/articles/204612.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

hierarchical cluster analysis
discriminant analysis
principal component analysis
multiple linear
regression analysis

Opis:

The Malacca River basin experienced river water pollution which caused a major deterioration to the ecosystems and environmental health. This study is carried out to assess the water quality data and identify the pattern of water pollution sources in the study area, and also to develop a predictive performance of water quality in the Malacca River basin. A chemometric approach using a combination of HCA, DA, PCA, and MLR, was applied into twenty water quality variables from nine sampling stations that were collected from January until December of 2015 in the river basin. HCA pointed out three clusters, namely Cluster 1 (C1) with low pollution source, Cluster 2 (C2) with moderate pollution source, and Cluster 3 (C3) with high pollution source. In the DA analysis, the results showed 21 variables, 12 variables, and 9 variables for standard mode, forward stepwise mode, and backward stepwise mode, respectively. Meanwhile, the PCA indicated that the main source of pollutants is detected from residential, industrial, commercial, agricultural, animal livestock, as well as forest land. Among the three models developed from MLR analysis, C3 with a high pollution source is detected to be the most suitable model to be used for the prediction of Water Quality Index in the Malacca River basin. This study proposed for an effective river water quality management by having new water quality monitoring network to be designed for more practical use in order to reduce time and effort, as well as cost saving purposes.

Źródło:

Archives of Environmental Protection; 2018, 44, 4; 111-122
2083-4772
2083-4810

Pojawia się w:

Archives of Environmental Protection

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Music Recommendation System

Autorzy:

Hoffmann, P.
Kaczmarek, A.
Spaleniak, P.
Kostek, B.

Powiązania:

https://bibliotekanauki.pl/articles/308747.pdf

Data publikacji:

2014

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

feature vectors
music classification
music information retrieval
music parametrization
principal component analysis

Opis:

The paper focuses on optimization vector content feature for the music recommendation system. For the purpose of experiments a database is created consisting of excerpts of music files. They are assigned to 22 classes corresponding to different music genres. Various feature vectors based on low-level signal descriptors are tested and then optimized using correlation analysis and Principal Component Analysis (PCA). Results of the experiments are shown for the variety of feature vectors. Also, a music recommendation system is presented along with its main user interfaces.

Źródło:

Journal of Telecommunications and Information Technology; 2014, 2; 59-69
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Using chemometrics to identify water quality in Daya Bay, China

Autorzy:

Wu, M.-L.
Wang, Y.-S.
Sun, C.-C.
Wang, H.
Lou, Z.-P.
Dong, J.-D.

Powiązania:

https://bibliotekanauki.pl/articles/49096.pdf

Data publikacji:

2009

Wydawca:

Polska Akademia Nauk. Instytut Oceanologii PAN

Tematy:

robust principal component analysis
water quality
chemometrics
China
cluster analysis
Daya Bay

Opis:

In this paper, chemometric approaches based on cluster analysis, classical and robust principal component analysis were employed to identify water quality in Daya Bay (DYB), China. The results show that these approaches divided water quality in DYB into two groups: stations S3, S8, S10 and S11 belong to cluster A, which lie in Dapeng Cove, Aotou Harbor and the north-eastern part of DYB, where water quality is related mainly to anthropogenic activities. The other stations belong to cluster B, which lie in the southern, central and eastern parts of DYB, where the quality is related mainly to water exchange with the South China Sea. Cluster analysis yields good results as a first exploratory method for evaluating spatial difference, but it fails to demonstrate the relationship between variables and environmental quality on the one hand and the untreated data on the other. However, with the aid of suitable chemometric approaches, the relationship between samples or variables can be investigated. Classical and robust principal component analysis can provide a visual aid for identifying the water environment in DYB, and then extracting specific information about relationships between variables and spatial variation trends in water quality.

Źródło:

Oceanologia; 2009, 51, 2; 217-232
0078-3234

Pojawia się w:

Oceanologia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Wielocechowa analiza różnorodności fenotypowej mieszańców ziemniaka uzyskanych z krzyżowań tetraploid × diploid
Multivariate analysis of phenotypic diversity in the tetraploid × diploid hybrid progenies of potatoes

Autorzy:

Domański, Leszek
Mańkowski, Dariusz R.
Flis, Bogdan
Jakuczun, Henryka
Zimnoch-Guzowska, Ewa

Powiązania:

https://bibliotekanauki.pl/articles/2198318.pdf

Data publikacji:

2012-06-28

Wydawca:

Instytut Hodowli i Aklimatyzacji Roślin

Tematy:

analiza składowych głównych
zmienność wielocechowa
ziemniak
multivariable variation
potato
principal component analysis

Opis:

Osiemdziesiąt rodów ziemniaka uzyskanych z czterech interploidalnych krzyżowań 4x-2x zostało ocenione na 12 cech użytkowych, w tym morfologii bulw, w Instytucie Hodowli i Aklimatyzacji Roślin, Oddział Młochów w latach 2008–2009. Celem badań była ocena genotypowej różnorodności wśród rodów ziemniaka i uzyskanie wglądu w strukturę wielocechowej zmienności. Analiza składowych głównych (PCA) wyodrębniła pięć składowych głównych, które wyjaśniały 78,4% łącznej wariancji wśród rodów ziemniaka. Wykazana przez analizę PCA genotypowa różnorodność potomstwa 4x-2x daje szansę na wyselekcjonowanie wartościowych tetraploidalnych rodów zarówno na jadalny, jak i przetwórczy kierunek użytkowania. Spośród wyodrębnionych pięciu składowych głównych pierwsze trzy były najważniejsze. Pierwsza składowa (29,9% zmienności) była głównie skorelowana z regularnością kształtu, głębokością oczek i ciemnieniem enzymatycznym. Druga składowa, tłumacząca 16% łącznej zmienności była dodatnio skorelowana z plonem bulw, średnią masą bulwy i spłaszczeniem bulw. Trzecia składowa, wyjaśniająca 13,2% łącznej zmienności była pozytywnie skorelowana z zawartością skrobi i barwą chipsów.
Eighty potato clones derived from interploid crosses 4x-2x were evaluated for 12 tuber morphological and agronomic traits at the Plant Breeding and Acclimatization Institute — National Research Institute, Research Center Młochów during 2008–2009. The objective of the research was to assess the genotypic diversity among potato clones and to gain insight into the structure of multivariable variation. The principal component analysis (PCA) distinguished five principle components which explained 78.4% of the total variance among potato clones. The demonstrated genotypic diversity of 4x-2x progenies gives the chance for selecting valuable tetraploid clones for both table and processing use. Out of five PCs, the first three were the most important. The first PC (29.9% of total variance) was mostly correlated with shape regularity, depth of eyes and enzymatic browning. The second PC, that explained 16.2% of the total variance, was positively correlated with tuber yield, mean tuber weight and tuber flatness. The third PC explaining 13.2% of the total variance was positively correlated with starch content and chip colour.

Źródło:

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin; 2012, 264; 189-194
0373-7837
2657-8913

Pojawia się w:

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

A Multivariate Technique to Develop Hybrid Water Quality Index of the Bengawan Solo River, Indonesia

Autorzy:

Lusiana, Evellin Dewi
Mahmudi, Mohammad
Hutahaean, Sarah Mega
Darmawan, Arief
Buwono, Nanik Retno
Arsad, Sulastri
Musa, Muhammad

Powiązania:

https://bibliotekanauki.pl/articles/2026733.pdf

Data publikacji:

2022

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

principal component analysis
WQI
water quality index
variable selection
water quality assessment

Opis:

Surface water resource, such as river, is constantly contaminated by domestic and industrial pollutants. In order to properly manage the water resource, a composite index for water quality assessment, such as water quality index (WQI), has been designed to monitor and evaluate the properties of surface water. However, this index is quite subjective in terms of determination of relative weights. A principal component analysis (PCA) can be used to reduce the dimension and subjectivity of water quality variables. The purpose of this study was to implement the use of hybrid PCA and WQI methods to assess and monitor the water quality of the Bengawan Solo River, which is located in Java Island, Indonesia. The result suggested that COD, BOD, TSS, TDS, nitrate, nitrite, and ammonia were the main factors that determine water quality of the Bengawan Solo River. Furthermore, it was revealed that most samples from the river showed water quality status as slightly polluted. In addition to this, the seasonal variation of the PCWI values indicated a significant increase of water pollution in the Bengawan Solo River per year.

Źródło:

Journal of Ecological Engineering; 2022, 23, 2; 123-131
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

On the potential for using selected PCA-based methods to analyze the crime rate in Poland

Autorzy:

Misztal, Małgorzata

Powiązania:

https://bibliotekanauki.pl/articles/424843.pdf

Data publikacji:

2019

Wydawca:

Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu

Tematy:

crime
criminal offence
multivariate exploratory data analysis
principal component analysis
factorial maps

Opis:

The aim of the paper is to assess the potential for using some selected PCA-based methods to analyze the spatial diversity of crime in Poland during 2000-2017. Classical principal components analysis (PCA) deals with two-way matrices, usually taking into account objects and variables. In the case of data analyzed in the study, apart from two dimensions (objects – voivodships, variables – criminal offences), there is also the dimension of time, so the dataset can be seen as data cube: objects × variables × time. Therefore, this type of data requires the use of methods handling three-way data structures. In the paper the variability of some selected categories of criminal offences in time (2000- -2017) and space (according to voivodships) is analyzed using the between-class and the within-class principal component analysis. The advantage of these methods is, among others, the possibility of the graphical presentation of the results in two-dimensional space with the use of factorial maps.

Źródło:

Econometrics. Ekonometria. Advances in Applied Data Analytics; 2019, 23, 2; 15-32
1507-3866

Pojawia się w:

Econometrics. Ekonometria. Advances in Applied Data Analytics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Forecast of prices and volatility on the day ahead market

Autorzy:

Ganczarek-Gamrot, Alicja

Powiązania:

https://bibliotekanauki.pl/articles/425278.pdf

Data publikacji:

2013

Wydawca:

Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu

Tematy:

principal component analysis (PCA)
SARIMA model
DCC model
Value-at- -Risk
portfolio

Opis:

The subject of this paper is the forecast of prices and volatility on the Day Ahead Market (DAM). The analysis was made for two portfolios of four contracts from 30.03.2009 to 28.10.2011 for two fixings on DAM. Four out of 24 contracts noted on DAM were chosen by PCA. Prices were forecast by the SARIMA models incorporating autocorrelation and seasonality. Value-at-Risk calculated through the DCC model was used to forecast volatility. These models describe well the prices and volatility on the DAM and may be used for forecasting purposes. Prices on fixing 2 are characterized by higher volatility than prices on fixing 1.

Źródło:

Econometrics. Ekonometria. Advances in Applied Data Analytics; 2013, 1(39); 111-120
1507-3866

Pojawia się w:

Econometrics. Ekonometria. Advances in Applied Data Analytics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Major, minor, and trace elements in whole blood of patients with different leukemia patterns

Autorzy:

Khuder, A.
Bakir, M. A.
Solaiman, A.
Issa, H.
Habil, K.
Mohammad, A.

Powiązania:

https://bibliotekanauki.pl/articles/146612.pdf

Data publikacji:

2012

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

leukemia
principal component analysis
Student's t test
whole blood
X-ray fluorescence

Opis:

The elemental sensitivity method for X-ray fluorescence analysis was applied to determine S, Cl, K, Ca, Fe, Cu, Zn, Br, and Rb in the whole blood of leukemia patients and healthy volunteers. Leukemia samples were classified according to type, growth, and age of participants. Student’s t-test results showed that, the mean concentration of the studied elements was significantly lower in leukemia patients than that in controls. Strong mutual correlations (r greather than 0.50) in the whole blood of leukemia patients were observed between S-Ca, K-Fe, K-Ca, Fe-Zn, K-Zn, K-Rb, Fe-Rb, Zn-Rb, S-Cl, S-K, Ca-Fe, Cl-Ca, and Ca-Rb; whereas, S-K, S-Ca, S-Cl, Cl-K, Cl-Ca, Fe-Zn, Zn-Rb, Fe-Rb, K-Fe, and Zn-Br exhibited strong relationships (r greather than 0.50) in the whole blood of controls, all were significant at p less than 0.05. Significant differences between grouping of studied elements in the control group and all classified leukemia groups, except younger age-group, were obtained using principal component analysis. The study indicated appreciably different patterns of element distribution and mutual relationships in the whole blood of leukemia patients in comparison with controls.

Źródło:

Nukleonika; 2012, 57, 3; 389-399
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

Forecasting Yield Curves in an Adaptive Framework

Autorzy:

Chen, Ying
Li, Bo

Powiązania:

https://bibliotekanauki.pl/articles/483285.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

interest rates
functional principal component analysis
local parametric model
Nelson-Siegel model

Opis:

Forecasting yield curves with regime switches is important in academia and financial industry. As the number of interest rate maturities increases, it poses difficulties in estimating parameters due to the curse of dimensionality. To deal with such a feature, factor models have been developed. However, the existing approaches are restrictive and largely based on the stationarity assumption of the factors. This inaccuracy creates non-ignorable financial risks, especially when the market is volatile. In this paper, a new methodology is proposed to adaptively forecast yield curves. Specifically, functional principal component analysis (FPCA) is used to extract factors capable of representing the features of yield curves. The local AR(1) model with time-dependent parameters is used to forecast each factor. Simulation and empirical studies reveal the superiority of this method over its natural competitor, the dynamic Nelson-Siegel (DNS) model. For the yield curves of the U.S. and China, the adaptive method provides more accurate 6- and 12-month ahead forecasts.

Źródło:

Central European Journal of Economic Modelling and Econometrics; 2011, 3, 4; 237-259
2080-0886
2080-119X

Pojawia się w:

Central European Journal of Economic Modelling and Econometrics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

Stylistyka ceramiki grupy wschodniej kultury amfor kulistych – ujęcie strukturalne
Pottery style of the eastern group of the Globular Amphora culture – structural analysis

Autorzy:

Sieradzka, Elżbieta

Powiązania:

https://bibliotekanauki.pl/articles/567563.pdf

Data publikacji:

2017

Wydawca:

Uniwersytet Rzeszowski. Instytut Archeologii Uniwersytetu Rzeszowskiego. Muzeum Okręgowe w Rzeszowie

Tematy:

Globular Amphora culture
pottery style
statistical analysis
principal component analysis
network analysis

Opis:

In the classical approach presented by Marzena Szmyt, statistical analysis of the ceramic style of the eastern group of Globular Amphora Culture was based on detailed classification of ornaments and their co-occurrence within grave inventories. This paper introduces an alternative proposition, focusing on structural analysis of decoration of vessels. Additionally, in order to show the distribution of stylistic features among the graves, some elements of the network analysis were implemented.

Źródło:

Materiały i Sprawozdania Rzeszowskiego Ośrodka Archeologicznego; 2017, 38; 13-26
0137-5725

Pojawia się w:

Materiały i Sprawozdania Rzeszowskiego Ośrodka Archeologicznego

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 48.

Tytuł:

Slovak Creativity Index – A PCA Based Approach

Autorzy:

Hudec, Oto
Klasová, Slávka

Powiązania:

https://bibliotekanauki.pl/articles/623791.pdf

Data publikacji:

2016-07-07

Wydawca:

Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego

Tematy:

Slovak creativity index
urbanisation
principal component analysis
R11
C21
A13

Opis:

The article aims at transferring the European Creativity Index (ECI) assessment from the country to regional comparison basis, focusing on the case of Slovakia. The newly created Slovak Creativity Index (SCI) has the power to assess the creativity potential found in the Slovak regions. The Principal Component Analysis has been chosen as an advanced method for establishing a well-designed overall Index and six sub-indices to show differences and variability according to all dimensions of the creative potential. The research also explains several relations between creative performance of the regions by several factors such as urbanisation, cultural environment, human capital and tolerance.

Źródło:

European Spatial Research and Policy; 2016, 23, 1
1231-1952
1896-1525

Pojawia się w:

European Spatial Research and Policy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 49.

Tytuł:

Biometric watermarking for security enhancement in digital images

Autorzy:

Wójtowicz, W.

Powiązania:

https://bibliotekanauki.pl/articles/115437.pdf

Data publikacji:

2013

Wydawca:

Fundacja na Rzecz Młodych Naukowców

Tematy:

images security
watermarking technique
discrete wavelet transform (DWT)
biometrics
principal component analysis (PCA)

Opis:

In this paper some preliminary investigation on combination of watermarking technique with biometric data to increase security of digital images in case of medical images is proposed. Performance of watermarking algorithm, based on discrete wavelet transform (DWT) decomposition, that incorporates biometric watermark is elaborated. The frequency domain were chosen as it is proven, that this domain provides better robustness against attacks and leads to less perceptibility of an embedded watermark. To assure confidentiality of patient data their hand geometry features are embedded instead of patient’s name. Proposed system is evaluated by measuring the similarity between embedded and extracted biometric codes.

Źródło:

Challenges of Modern Technology; 2013, 4, 4; 7-11
2082-2863
2353-4419

Pojawia się w:

Challenges of Modern Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 50.

Tytuł:

Assessment of the influence of soil properties on 137Cs accumulation in Of horizon in forest soils

Autorzy:

Ziembik, Z.
Dołhańczuk-Śródka, A.
Wacławek, M.

Powiązania:

https://bibliotekanauki.pl/articles/148398.pdf

Data publikacji:

2010

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

137Cs
forest soil
physicochemical parameters
cluster analysis (CA)
principal component analysis (PCA)

Opis:

The work focuses on assessment of soil physicochemical parameters influence on 137Cs accumulation in Of soil horizon. Besides organic matter content and pH, the parameters related to sorption properties and mobile ions concentration were considered. The data were transformed using Box-Cox formula. To find mutual relationships between variables cluster analysis (CA) and principal components analysis (PCA) were used. It was found that the transformed physicochemical parameters in Of horizon are more or less related with each other but no linear or nearly linear relationships between 137Cs activity and physicochemical parameters were found.

Źródło:

Nukleonika; 2010, 55, 2; 205-212
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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