Temat: multiple models - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Real-time implementation of multiple model based predictive control strategy to air/fuel ratio of a gasoline engine
Autorzy:: Wojnar, S
Polóni, T
Šimončič, P
Rohal’-Ilkiv, B
Honek, M
Csambál, J
Tematy:: model predictive control
multiple models
air/fuel ratio
spark ignition engine
ARX models; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/229632.pdf Link otwiera się w nowym oknie
Opis:: Growing safety, pollution and comfort requirements influence automotive industry ever more. The use of three-way catalysts in exhaust aftertreatment systems of combustion engines is essential in reducing engine emissions to levels demanded by environmental legislation. However, the key to the optimal catalytic conversion level is to keep the engine air/fuel ratio (AFR) at a desired level. Thus, for this purposes more and more sophisticated AFR control algorithms are intensively investigated and tested in the literature. The goal of this paper is to present for a case of a gasoline engine the model predictive AFR controller based on the multiple-model approach to the engine modeling. The idea is to identify the engine in particular working points and then to create a global engine's model using Sugeno fuzzy logic. Opposite to traditional control approaches which lose their quality beside steady state, it enables to work with satisfactory quality mainly in transient regimes. Presented results of the multiple-model predictive air/fuel ratio control are acquired from the first experimental real-time implementation on the VW Polo 1390 cm3 gasoline engine, at which the original electronic control unit (ECU) has been fully replaced by a dSpace prototyping system which execute the predictive controller. Required control performance has been proven and is presented in the paper.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Design of unknown input observers for non-linear stochastic systems and their application to robust fault diagnosis
Autorzy:: Witczak, M.
Korbicz, J.
Józefowicz, R.
Tematy:: fault diagnosis
unknown input
unscented Kalman filter
interactive multiple models
non-linear systems; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Badań Systemowych PAN
Powiązania:: https://bibliotekanauki.pl/articles/205987.pdf Link otwiera się w nowym oknie
Opis:: The paper deals with the problem of designing filters for non-linear discrete-time stochastic systems. In particular, it is shown how to design an unknown input filter for a single (constant) unknown input distribution matrix, which guarantees that the effect of a fault will not be decoupled from the residual. Subsequently, the problem of using one, fixed disturbance distribution matrix is eliminatek by using the interacting multiple models algorithm to select an appropriate unknown input distribution matrix from a predefined set of matrices. The final part of the paper shows an illustrative example, which confirms the effectiveness of the proposed approach.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Motor Control: Neural Models and Systems Theory
Autorzy:: Doya, K.
Kimura, H.
Miyamura, A.
Tematy:: adaptacyjny układ sterowania
model wielokrotny
inverse model
adaptive control
cerebellum
reinforcement learning
basal ganglia
multiple models; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/908323.pdf Link otwiera się w nowym oknie
Opis:: In this paper, we introduce several system theoretic problems brought forward by recent studies on neural models of motor control. We focus our attention on three topics: (i) the cerebellum and adaptive control, (ii) reinforcement learning and the basal ganglia, and (iii) modular control with multiple models. We discuss these subjects from both neuroscience and systems theory viewpoints with the aim of promoting interplay between the two research communities.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A method of estimating the Return on Housing Investment (ROHI)
Autorzy:: Derkacz, Arkadiusz J.
Tematy:: multiple equation models
multiple variables
verification of the ROE ratio
apartment rentals
Return on Housing Investment; Pokaż więcej
Wydawca:: Główny Urząd Statystyczny
Powiązania:: https://bibliotekanauki.pl/articles/59193272.pdf Link otwiera się w nowym oknie
Opis:: The aim of the study was to develop a method for estimating the profitability of housing investments. Market practice shows that the profitability of this type of investment is influenced by specific determinants that are absent in the classical approach to profitability analysis. The most commonly used method is the Return on Equity (ROE) ratio, which is dedicated to enterprises. However, housing investments are becoming increasingly popular among individuals, while the classical ROE method proved suboptimal for such ventures (i.e. those involving the purchase of residential property and its subsequent rental to third parties). In this context, we made an attempt to develop a method that would make the estimation of the profitability level of this type of investment possible. Through the decomposition of the ROE ratio, a model for the Return on Housing Investment (ROHI) was created. This model was verified using real market data. Ultimately, we found that the ROHI method allows the estimation of the profitability level while taking into consideration the most important determinants characteristic of this type of investment.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Wpływ nieefektywności rynku nieruchomości na dokładność opisu wartości nieruchomości za pomocą liniowych modeli regresji wielorakiej
The influence of inefficiency of property market on the accuracy of description of property value using linear models of multiple regression
Autorzy:: Meszek, W.
Dziadosz, A.
Tematy:: modele regresji wielorakiej
rynek nieruchomości
rynek nieefektywny
multiple regression models
real estate market
market inefficient; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/403159.pdf Link otwiera się w nowym oknie
Opis:: Szacowanie rynkowej wartości nieruchomości opiera się w głównej mierze na cenach transakcyjnych, które powinny w pełni odzwierciedlać charakterystyczne ich cechy. Rynek nieruchomości ze względu na swoją specyfikę jest jednak rynkiem nieefektywnym, na którym ceny transakcyjne w różnym (i nieznanym) stopniu są estymatorami wartości nieruchomości. Zakres referatu, w oparciu o eksperyment statystyczny, obejmuje analizę porównawczą pomiędzy efektami procesu wyceny zrealizowanego w warunkach rynku efektywnego i w warunkach rynku (w różnym stopniu) nieefektywnego.
The evaluation of the market value of the property is mainly based on transaction prices which should reflect its characteristic features. In the case of an efficient market, the property price reflects its true value. However, it is more often the case to deal with an inefficient market (within different scope and to a different degree) during the evaluation procedure, which determines its accuracy. This paper contains an example of statistical analysis of a selected property base with the emphasis put on previously mentioned issues concerning the inefficiency of the market using reliability evaluation coefficient.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Modele oceny zagrożenia przedsiębiorstwa upadłością jako narzędzie diagnozy stanu finansowego spółek rynku kapitałowego
Bankruptcy risk assessment models as a tool for diagnosing the financial condition of capital market companies
Autorzy:: Kopczyński, Paweł
Tematy:: financial situation
listed companies
corporate failure prediction
bankruptcy
multiple discriminant analysis models
financial crisis; Pokaż więcej
Wydawca:: Stowarzyszenie Księgowych w Polsce
Powiązania:: https://bibliotekanauki.pl/articles/1064877.pdf Link otwiera się w nowym oknie
Opis:: Purpose: The main purpose of this article is to examine the usefulness of multiple discriminant analysis models in assessing the financial condition of individual enterprises, the state of the economy, and its sectors. The study assessed the financial situation of Polish listed companies at the end of the global economic crisis that started in 2007. Methodology/approach: Seven discriminant functions were used to assess the actual changes in the finan-cial situation of listed companies during the period of 2009–2014. In order to diagnose the end of the crisis, the period in which countries emerged from the global economic crisis was taken into account. The study covered 175 Polish companies listed on the regulated market operated by the Warsaw Stock Exchange, whose standalone financial statements were used. These companies belong to 22 sectors of the economy. It was assumed that the number of companies at risk of bankruptcy should have decreased during this period. Findings: The study showed that it is difficult to determine when the crisis ended and stopped affecting Polish listed companies. Their financial condition gradually improved during the period 2013–2014. Multiple discriminant analysis models are useful in assessing the risk of bankruptcy, but the study results show that it is safer to use several models simultaneously and to eliminate outliers. Research limitations/implications: The discriminant models used in the study are suitable for conducting research on large populations within enterprises and can be used by state and financial institutions (including banks) and authorities in Poland to facilitate the conduct of economic statistics, forecasting economic situation, etc. Originality/value: In Poland, many studies have been carried out on the usefulness of multiple discrimi-nant analysis models for the purposes of forecasting the bankruptcy of individual enterprises. However, there are few studies devoted to assessing the usefulness of the models in conducting research on large populations within enterprises (i.e., assessing the state of the economy and its sectors). This research helps to explore and fill this research gap.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Land clayey deposits compressibility investigation using principal component analysis and multiple regression tools
Autorzy:: Berrah, Yacine
Chegrouche, Aymen
Brahmi, Serhane
Boumezbeur, Abderrahmane
Tematy:: compressibility index
geotechnical parameters
principal component analysis
PCA
multiple regression models
indeks ściśliwości
parametry geotechniczne
analiza głównych składowych
regresja wielokrotna; Pokaż więcej
Wydawca:: Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Powiązania:: https://bibliotekanauki.pl/articles/2201674.pdf Link otwiera się w nowym oknie
Opis:: The settlement and compressibility magnitude of the major clayey and marly sediments in Tebessa area (N-E of Algeria) depends on several geotechnical parameters such as compression Cc and recompression Cs indices. The aim of this study was to investigate the parameters related to soil compressibility through tools of statistical analysis, which save time in comparison to multiply repeated laboratory tests. The study also adopted the principal component analysis (PCA) method to eliminate a number of uncorrelated variables that have no influence on the compressibility magnitude, or their impact is insignificant. The highest mean correlation coefficients were obtained for different contributing parameters. Multiple regression analysis has been performed to obtain the best fit model of the output Cc parameter taking into account the best correlation by adding parameters as regressors to reach the highest coefficient of regression R2 . The final obtained model of the present case study gives the best fit model with R2 of 0.92 which is a better value compared to different published models in the literature (R2 of 0.7 as maximum). The chosen input parameters using PCA combined with multiple regression analysis allow identifying the most important input parameters that noticeably affect the soil compression index, and provide with the best model for estimating the Cc index.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Assessment applicability of selected models of multiple discriminant analyses to forecast financial situation of Polish wood sector enterprises
Autorzy:: Adamowicz, Krzysztof
Noga, Tomasz
Wydawca:: Forest Research Institute in Poland and Polish Academy of Sciences
Opis:: In the last three decades forecasting bankruptcy of enterprises has been an important and difficult problem, used as an impulse for many research projects (Ribeiro et al. 2012). At present many methods of bankruptcy prediction are available. In view of the specific character of economic activity in individual sectors, specialised methods adapted to a given branch of industry are being used increasingly often. For this reason an important scientific problem is related with the indication of an appropriate model or group of models to prepare forecasts for a given branch of industry. Thus research has been conducted to select an appropriate model of Multiple Discriminant Analysis (MDA), best adapted to forecasting changes in the wood industry. This study analyses 10 prediction models popular in Poland. Effectiveness of the model proposed by Jagiełło, developed for all industrial enterprises, may be labelled accidental. That model is not adapted to predict financial changes in wood sector companies in Poland. The generally known Altman model showed the greatest effectiveness in the identification of enterprises at risk of bankruptcy. However, that model was burdened with one of the greatest errors in the classification of healthy enterprises as sick. The best effectiveness in the identification of enterprises not threatened with bankruptcy was found for forecasts prepared using the Prusak 2 model. However, forecasts based on those models were characterised by erroneous classification of sick companies as healthy. The model best fit to predict the financial situation of Polish wood sector companies was the Poznań model Pz = 3.562 · X1 + 1.588 · X2 + 4.288 · X3 + 6.719 · X4) – 2.368 where: X1 – net income/total assets; X2 – (current assets – stock)/current liabilities; X3 – fixed capital/total assets X4 – income from sales/sales revenue).
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 9.

Tytuł:: Ocena zdolności do kontynuowania działalności polskich spółek giełdowych w czasie kryzysu z wykorzystaniem modeli wielowymiarowej analizy dyskryminacyjnej
Assessment of the viability of Polish listed companies during the crisis with the application of multivariate discriminant analysis models
Autorzy:: Kopczyński, Paweł
Tematy:: sytuacja finansowa
kryzys
przewidywanie upadłości
bankructwo
modele wielowymiarowej analizy dyskryminacyjnej
analiza finansowa
wskaźniki finansowe
financial situation
crisis
corporate failure prediction
bankruptcy
multiple discriminant analysis models
financial statement analysis
financial ratios; Pokaż więcej
Wydawca:: Stowarzyszenie Księgowych w Polsce
Powiązania:: https://bibliotekanauki.pl/articles/516230.pdf Link otwiera się w nowym oknie
Opis:: Ogólnoświatowy kryzys gospodarczy na rynkach finansowych, który rozpoczął się w 2007 roku miał ogromny wpływ na sytuację na światowych giełdach. Na zachowanie inwestorów często wpływa wiele czynników, które determinują ich decyzje inwestycyjne. Nie zawsze postępują oni w sposób racjonalny, często mają skłonność do przesadnych reakcji i kierują się emocjami, dlatego też trudno jest wyjaśnić ich zachowania i decyzje w czasie kryzysu, zwłaszcza te dotyczące nagłej sprzedaży akcji. Ogromny spadek cen akcji na światowych giełdach był widoczny zwłaszcza we wczesnych stadiach kryzysu, ale prawdopodobnie nie był uzasadniony adekwatnym pogorszeniem rzeczywistej sytuacji finansowej spółek giełdowych. Światowy kryzys finansowy wywołał falę paniki i doprowadził do wyprzedaży akcji spółek notowanych na Giełdzie Papierów Wartościowych (GPW) w Warszawie. Wahania cen akcji nie zawsze odzwierciedlają rzeczywistą sytuację spółki, dlatego warto zbadać, czy kondycja spółek notowanych na GPW w rzeczywistości się pogorszyła i czy liczba firm zagrożonych bankructwem wzrosła w czasie trwania kryzysu. Głównym celem artykułu jest ocena wpływu ogólnoświatowego kryzysu gospodarczego na rynkach finansowych i bankowych na sytuację finansową i wyniki polskich spółek giełdowych. Do oceny rzeczywistych zmian w sytuacji finansowej polskich spółek giełdowych w okresie poprzedzającym kryzys (2006 r.) i w czasie kryzysu (lata 2007–2011) wykorzystano osiem modeli wielowymiarowej analizy dyskryminacyjnej. Pozwalają one przewidywać upadłość przedsiębiorstwa i oceniać sytuację finansową firmy w sposób całościowy, z różnych punktów widzenia jednocześnie. Liczba firm zagrożonych bankructwem powinna – przynajmniej teoretycznie – wzrosnąć w czasie kryzysu. Badaniem objęto 175 polskich spółek notowanych na rynku regulowanym GPW w Warszawie. Ich dane finansowe pochodziły w całości z bazy danych Notoria Serwis, dostępnej poprzez stronę internetową Biblioteki Uniwersytetu Łódzkiego.
The Global Financial Crisis, which began in 2007, had a huge influence on the situation on world stock markets. The behavior of investors is often affected by various factors which can impact their investment decisions. As they do not always act rationally, have a tendency to overreact and cannot remove all emotional components from their decision-making process, it may be difficult to explain their behavior and investment decisions during the crisis, especially those concerning the sale of shares. The huge drop in share prices on world stock markets was visible in the early stages of the crisis, but it probably was not justified by actual deterioration of the financial situation of listed companies. The Global Financial Crisis triggered a wave of panic selling of shares on the Warsaw Stock Exchange (WSE). As the fluctuations in share prices do not always reflect the real economic situation of the companies, it is worth to examine whether the financial standing of companies listed on WSE actually deteriorated and whether the number of companies facing bankruptcy grew during the 2007 Crisis. The main purpose of this article is to evaluate the influence of the recent financial crisis on the financial situation and performance of Polish listed companies. Eight multiple discriminant analysis models were utilized to evaluate the real changes in the financial situation of Polish listed companies during the crisis (years 2006-2011). The aforementioned models enable prediction of corporate bankruptcy and measurement of financial health of companies. Theoretically, the number of companies facing bankruptcy should increase in time of crisis. As many as 175 joint-stock companies listed on the regulated market of the WSE were covered by the study. Their financial data were extracted from the Notoria Serwis database, which is available on the University of Lodz Library’s website.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Optimization of safety instrumented system design and maintenance frequency for oil and gas industry processes
Autorzy:: Redutskiy, Y.
Tematy:: emergency shutdown system
Markov models
multiple-criterion optimization
safety instrumented system
systems design
risk management; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/407133.pdf Link otwiera się w nowym oknie
Opis:: Oil and gas industry processes are associated with significant expenditures and risks. Adequacy of the decisions on safety measures made during early stages of planning the facilities and processes contributes to avoiding technological incidents and corresponding losses. Formulating straightforward requirements for safety instrumented systems that are followed further during the detailed engineering design and operations is proposed, and a mathematical model for safety system design is introduced in a generalized form. The model aims to reflect the divergent perspectives of the main parties involved in oil and gas projects, and, therefore, it is formulated as a multi-objective problem. Application of black box optimization is suggested for solving real-life problem instances. A Markov model is applied to account for device failures, technological incidents, continuous restorations and periodic maintenance for a given process and safety system configuration. This research is relevant to engineering departments and contractors, who specialize in planning and designing the technological solution.
Dostawca treści:: Biblioteka Nauki

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