Wyniki wyszukiwania - BazTech

1

Description of Residual Stress Distribution in the Surface Layer After Heat Treatment and Shot Peening

Skalski Konstanty, Mońka Grzegorz, Filipowski Ryszard

Transactions on Aerospace Research

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2023

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Nr 3 (272)

28--39

EN

The stress distribution function in the surface layer is created as a result of using stress measurements on the surfaces of C45 steel samples after shot peening. Stresses were measured by X-ray diffraction with the use of the PSF-3M device from the Rigaku Company. For measuring residual stresses, subsequent layers of the top surface of the material were used as a basis, and these were obtained through electrochemical etching. The test results i.e. distance into the material, sample hardness, shot type, stress) were entered into the stepwise multiple regression program. A record of residual stresses was obtained in the form of the second-degree regression function of three independent variables with interactions. The obtained analytical form of the residual stress function was used in the FUNVAL3.EXE program to calculate the tabular values of stresses permeating into the material. For the analytical description of the stress distribution, the REGPOLY.EXE regression program was used, which creates a polynomial functional form of the residual stress distribution. The plot form of the residual stress distribution was obtained using the EXCEL Microsoft Office 2000 program.

2

Predicting Young’s modulus of Indian coal measure rock using multiple regression and artificial neutral network

Chakraborty Sayantan, Bisai Rohan, Roy Rohit, Palaniappan Sathish Kumar, Pal Samir Kumar, Rao Karanam Uma Maheshwar

Journal of Sustainable Mining

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2023

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Vol. 22, iss. 1

41--54

EN

Accurate information on Young’s modulus (E) is required for simulating rock deformation in mines; on the other hand, it is very cumbersome to obtain in the laboratory and collecting drilled cores in sufficient amounts, especially in the case of soft rocks, is quite impossible. Empirical equations were deducted for - from easily determinable rock properties, and the final model was selected through different statistical strength parameter tests. The generalization of the equation was verified through the normal distribution tests of residues of the equation. R2 came to be 0.609 and was validated using an artificial neural network with an improved value of 0.73.

3

Choosing Important Traits for the Model of High-Yielding Winter Wheat Variety Based on the Results of Regional Ecological Varietal Testing

Lykhovyd Pavlo

Journal of Ecological Engineering

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2023

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Vol. 24, nr 6

8--12

EN

Current study is devoted to the development of an ideotype of winter wheat variety for cultivation in the conditions of the South of Ukraine. The investigation is based on the results of regional ecological varietal testing, conducted in the Southern Steppe zone on the non-irrigated lands. Varietal traits, included in the study, embraced growing season duration, 1000 grains weight, plant height, and ear length. The results of the testing were further processed using statistical procedures of linear Pearson’s correlation analysis and multiple regression analysis. As a result, the model of a winter wheat variety for the non-irrigated lands of the South of Ukraine was developed. The developed model is characterized by very high fitting quality (R2 = 0.9476) and good prediction accuracy (MAPE = 23.27%). According to the model, the variety should be late ripening with moderate to high plant height to provide the highest grain yield. The trait of 1000 grains weight was found out to be unimportant. The main trait, providing for the grain yield increase, is growing season duration, which must be long enough. Further ecological varietal testing studies with inclusion of additional varietal traits, such as cold-resistance, drought-resistance, frost-resistance, tolerance to diseases, etc., are to be conducted to extend the ideotype of winter wheat.

4

Prediction of compression strength of bamboo reinforced low-density polyethylene waste (LDPEw) composites

Ndukwe Agha Inya, Umoh Solomon, Ugwochi Chimezie, Ogbuji Christian, Ngolube Chinedu, Aliegu Ferdinand, Izuegbu Lilian

Composites Theory and Practice

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2022

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R. 22, nr 3

142--149

EN

In this work, the compression strength of bamboo reinforced low-density polyethylene waste (water sachet waste) composites was predicted. The composites were produced using the compression moulding technique with the following formulations: LDPEw, 5, 10, 15, and 20 wt.% filler. The hardness and compression strength of the examined composites were found to increase when the amount of filler was raised, with the formulation containing 20 wt.% filler having the highest hardness and compression strength values of 59.37 HV and 12.72 MPa, respectively. The control (LDPEw) gave the lowest values of hardness (41.57 HV) and compression strength (8.6 MPa). Multiple regression (MR) and artificial neural networks (ANN) were utilized to predict the experimental compression strength of the produced composites with the hardness and filler composition as independent variables. The mean squared error results indicated that when compared with the multiple regression forecasts, the artificial neural network predictions not only had smaller errors but were also closer to the experimental compression strength values. It is recommended that other methods of producing composites, such as the pulverization process with a 40% higher filler content than what was used in this work, should be studied to ascertain if they provide better composite materials.

5

Sustainable deployment of crushed concrete aggregates strengthened with cement and sand

Sharma V., Kumar A., Kaur A.

Archives of Materials Science and Engineering

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2022

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Vol. 113, nr 1

19--34

EN

Purpose: Paper assessed the feasibility of crushed concrete aggregates (CCA), a subsidiary of construction and demolition (C&D) waste, blended with cement and sand to form a composite for civil engineering field applications. Design/methodology/approach: The compaction and strength characteristics of CCA were observed by conducting Proctor compaction and California Bearing Ratio (CBR) tests. Different proportions of CCA, sand and cement were used. Moreover, the effect of curing period (0, 4, 7, 14 and 28 days) was also studied. In addition, regression analyses were performed to develop empirical expressions to predict the compaction and strength characteristics of the CCA composite. Findings: Increasing the CCA content up to 50% increases the maximum dry unit weight (MDUW) and decreases the optimum moisture content (OMC). However, on further increasing its content the MDUW decreases and OMC increases. Percent increase in the CBR value can go up to 412% if the CCA content is increased up to 50%. However, the percent reduction in CBR of about 20% can take place if 100% CCA content is used. Moreover, multiple regression shows that the experimental results are in good agreement with the predicted values. Research limitations/implications: The results obtained are purely dependent on the type of material. However, they are in favour of the used material as a probable option for road sub-base layer, and also for reducing burden on available natural resources. Therefore, it is recommended to conduct some initial tests to confirm the feasibility of the material. Practical implications: The proposed study will guide the design Engineers to choose CCA as one of the potential materials for road construction. Originality/value: It was observed that there is a need to maximize the utilization of C&D waste without making any compromise with its mechanical properties. So keeping that in view, the present study was conducted.

6

Modelling and Analysis of the Synergistic Alloying Elements Effect on Hardenability of Steel

Sitek Wojciech, Trzaska Jacek, Gemechu W. F.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

102--108

EN

The paper presents a methodology of modeling relationships between chemical composition and hardenability of structural alloy steels using computational intelligence methods, that are artificial neural network and multiple regression models. Particularly, the researchers used unidirectional multilayer teaching method based on the error backpropagation algorithm and a quasi-newton methods. Based on previously known methodologies, it was found that there is no universal method of modeling hardenability, and it was also noted that there are errors related to the calculation of the curve. The study was performed on large set of experimental data containing required information on about the chemical compositions and corresponding Jominy hardenability curves for over 400 data steel heats with variety of chemical compositions. It is demonstrated that the full practical usefulness of the developed models in the selection of materials for particular applications with intended performance in the area of application.

7

Real estate valuation algorithm for large local markets

Bitner Agnieszka, Frosik Małgorzata

Advances in Geodesy and Geoinformation

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2022

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Vol. 71, no. 1

art. no. e20, 2022

EN

The article deals with issues related to the application of statistical methods used in the valuation process. The proposed algorithm for real estate valuation can be used in the statistical market analysis method in the process of mass appraisal. The algorithm uses a multiple linear regression model. Legal considerations indicate the need for such an algorithm for the determination of the value of representative properties. Due to the large size of the database of comparables, the proposed algorithm can be used only to appraise typical properties. A good statistical model is parsimonious, that is, it uses as few mathematical concepts as possible in a given situation. A model should extract what is systematic in the results observed, allowing for the presence of purely random deviations. The article discusses the basic principles of building a good statistical model. Attention is drawn to the number of market attributes that are entered into the model and the range of their values. As few explanatory variables as possible should be entered into the model to explain the phenomenon under study. Explanatory variables are only those characteristics of the property that differentiate prices in a given market defined and adopted by the appraiser as the basis for valuation. The article highlights the importance of taking into account market changes during the period under study.

8

Expert evaluation of road infrastructure management

Urbański Mariusz, Sudyka Jacek, Grondys Katarzyna

Roads and Bridges - Drogi i Mosty

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2021

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Vol. 20, no. 4

465--492

EN

A dense and modern road network determines the proper functioning of trade-in economically developed countries. The aim of this article is to assess the influence of individual road infrastructure components on their performance in terms of traffic flow. To obtain a complete and comprehensive description of the problem, a mixed method of quantitative data analysis was used based on available statistical databases including information on linear and nodal infrastructure operating in the European Union. In light of the problem under consideration, a multi-stage statistical analysis was conducted. Factor analysis and multiple linear regression were used to assess the heterogeneity of the data and estimate the parameters of the models to explain the various components of road infrastructure performance. In turn, based on the k-means classification analysis, groups of EU countries differing in road network performance were identified. The results indicated that the extracted road network factors contribute to improving the performance of road infrastructure in its various study areas.

PL

Gęsta i nowoczesna sieć drogowa warunkuje właściwe funkcjonowanie wymiany handlowej w krajach rozwiniętych gospodarczo. Celem pracy jest ocena wpływu poszczególnych składników infrastruktury drogowej na jej wydajność w aspekcie płynności ruchu przewozowego. Na potrzeby osiągnięcia kompletnego oraz kompleksowego opisu zagadnienia, w artykule zastosowano metodę mieszaną analizy danych ilościowych pozyskanych w oparciu o dostępne bazy statystyczne obejmujące informacje o infrastrukturze liniowej i punktowej funkcjonującej na terenie Unii Europejskiej. W świetle rozważanego problemu przeprowadzono wieloetapową analizę statystyczną. Do oceny heterogeniczności danych i do oszacowania parametrów modeli wyjaśniania poszczególnych składowych wydajności infrastruktury drogowej zastosowano analizę czynnikową oraz wielowymiarowej regresji liniowej. Z kolei w oparciu o przeprowadzoną analizę klasyfikacji metodą k-średnich zidentyfikowano grupy krajów unijnych różniące się wydajnością sieci drogowej. Wyniki wskazały, że wyodrębnione czynniki sieci drogowej przyczyniają się do poprawy wydajności infrastruktury drogowej w jej poszczególnych badanych obszarach.

9

Wyznaczanie funkcji trwałości ostrza przy toczeniu

Filipowski Ryszard, Ziętarski Stanisław

Obróbka Metalu

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2021

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nr 4

36--40

PL

Przedstawiono algorytm tworzenia metodą skróconą funkcji trwałości ostrza przy toczeniu. Funkcję trwałości ostrza dla toczenia określają trzy parametry (v,f, a). Ich przestrzeń badań jest ograniczona wartościami minimalną i maksymalną. c p. Materiałem obrabianym była stal C55, ostrze narzędzia wykonane było z węglika spiekanego S10. Przyjęto plan badań z punktami gwiezdnymi o ramieniu α=1,414. Liczba badań wynosi 24 punkty. W punkcie centralnym planu wykonuje się pełny eksperyment zużycia ostrza. Za pomocą programu regresji wielomianowej REG6IJ5 tworzy się bezwymiarową charakterystykę zużycia ostrza. W pozostałych punktach planu wykonuje się eksperymenty krótkie, mierząc przyrost zużycia ostrza (∆VB) i czas skrawania (∆t). Trwałość ostrza w punkcie centralnym planu badań T, jej charakterystykę bezwymiarową oraz rezultaty krótkiego eksperymentu skrawania wykorzystuje się do obliczenia trwałości Tw pozostałych punktach planu badań. Uzyskana funkcja i trwałości ostrza przy toczeniu ma formę wykładniczą lub wielomianową drugiego stopnia. Funkcję trwałości ostrza wykorzystuje się do obliczenia parametrów skrawania w badanej przestrzeni czynnikowej oraz do obliczenia normy czasu w operacji toczenia.

EN

An algorithm has been developed for creating the edge life function using the shortened method for turning. The edge life function for turning is defined by three parameters: v, f, a. Their test space is bounded by minimum c p and maximum values of parameters. The test material was C55 steel and the tool blade was carbide. A five-level survey plan with star points of arm =1,414 was adopted. The number of studies was 24. A full edge wear experiment was performed at the focal point of the plan. The dimensionless characteristics of edge wear were developed using the REG6IJ5 polynomial regression program. At other points in the plan, short experiments were performed, measuring the increment of edge wear and cutting time (∆B, t). The edge life T at the focal point i i of the test plan, its dimensionless characteristics, the results of a short cutting experiment were used to calculate the life T i at the other points of the test plan. Blade life T, i=1,2,… , 24 and i the corresponding cutting parameters (v, f, a) are entered into ci i pi the stepwise multiple regression program REGSTEP. The resulting function of edge life for turning T = f(v, f, a) has an c p exponential or polynomial form of second degree. The edge life function can be used to calculate the cutting parameters in the factor space under study and to calculate the time standard in a turning operation.

10

Szacowanie ilości materii organicznej na podstawie zawartości pierwiastków śladowych

Przelaskowska Anna, Zagórska Urszula, Mroczkowska-Szerszeń Maja, Ziemianin Konrad

Nafta-Gaz

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2021

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R. 77, nr 4

219--226

PL

Wiele pierwiastków śladowych wykazuje związki z materią organiczną TOC. Zależności te pozwalają na wykorzystanie pomiarów składu chemicznego do modelowania zawartości TOC. Celem przedstawionej pracy była ocena możliwości szacowania ilości materii organicznej na podstawie zawartości pierwiastków śladowych takich jak: Ni, Cu, Mo, U, V, Zn, Cr, Sr, Pb i Co dla głębokomorskich łupków sylurskich. Przebadano związki korelacyjne pomiędzy poszczególnymi pierwiastkami i zawartością materii organicznej. Następnie utworzono modele pozwalające na wyliczenie ilości materii organicznej na podstawie zawartości pierwiastków, dla których zaobserwowano znaczące związki z TOC. Wykorzystano zarówno bardziej dokładne badania składu chemicznego wykonane metodą spektrometrii masowej ICP-MS, jak i pomiary o niższej wykrywalności wykonane przenośnym spektrometrem fluorescencji rentgenowskiej EDXRF. Stwierdzono zależności pomiędzy zawartością pierwiastków śladowych a ilością materii organicznej TOC dla pierwiastków takich jak: V, Cu, U, Ni, Mo, Cr (metoda ICP-MS) oraz V, Cu, Cr i Ni (metoda XRF). Za pomocą metody regresji wielorakiej skonstruowano modele o współczynnikach determinacji R2 od 0,84 do 0,92 (dla metody ICP-MS) i od 0,75 do 0,78 (dla metody XRF) umożliwiające szacowanie ilości materii organicznej na podstawie zawartości pierwiastków śladowych. Uzyskane modele matematyczne pozwalają na wyliczanie zawartości materii organicznej TOC dla głębokomorskich, bogatych w materię organiczną łupków sylurskich na bazie pomiarów pierwiastków śladowych wykonanych metodą spektrometrii masowej ICP-MS oraz metodą fluorescencji rentgenowskiej XRF. Szczególnie istotna jest możliwość wykorzystania pomiarów przeprowadzonych przenośnym spektrometrem fluorescencji rentgenowskiej. Badania te są szybkie, mogą być prowadzone na próbkach okruchowych w trakcie trwania wiercenia. Modele oparte na wynikach XRF pozwalają więc w szybki sposób modelować zawartość TOC jeszcze w trakcie wiercenia.

EN

Many trace elements are associated with organic matter. The total organic carbon (TOC) content can be thus calculated basing on the chemical composition measurements. The aim of the presented paper was to evaluate the possibility of estimating the organic matter amount on the basis of trace elements such as: Ni, Cu, Mo, U, V, Zn, Cr, Sr, Pb and Co, for Silurian black shales. Correlations between individual elements and total organic carbon were analysed. Next, mathematical models allowing to calculate the amount of organic matter based on the content of elements significantly related to TOC were constructed. Both more accurate chemical composition analyses (ICP-MS mass spectrometry method) and measurements of lower detectability performed with portable X-ray fluorescence spectrometer EDXRF were used. The relationships between the content of trace elements and the total organic carbon content TOC were found for such elements as: V, Cu, U, Ni, Mo, Cr (ICP-MS) and V, Cu , Cr and Ni (XRF). Mathematical models allowing for TOC quantification based on trace elements, characterized by determination coefficients R2 from 0.84 to 0.92 (for ICP MS method) and from 0.75 to 0.78 (for XRF method) were obtained with the use of the multiple regression method. The mathematical models allow to calculate the content of organic matter TOC for Silurian black shales on the basis of trace element data obtained by both mass spectrometry ICP-MS and X-ray fluorescence spectrometry EDXRF. The possibility of using measurements made with a portable X-ray fluorescence spectrometer is particularly important. Such measurements are fast and can be carried out on cuttings during the drilling process. Models based on XRF results therefore allow for quick modelling of the TOC content during the drilling process.

11

Elementy uczenia maszynowego na zajęciach matematyki

Bartłomiejczyk Agnieszka, Ptach Dawid, Wata Marcin

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

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2020

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Nr 71

27--30

PL

W artykule omówiono związki między matematyką kursową a wybranymi zagadnieniami związanymi z uczeniem maszynowym. Pokazano w jaki sposób proste operacje na macierzach pomagają serwisom VOD w rekomendacji tytułów filmowych zgodnych z zainteresowaniami użytkowników na podstawie ich wcześniejszych wyborów. Zaprezentowano również uproszczoną wersję algorytmu regresji wielorakiej stosowaną do wyceny nieruchomości oraz wspomniano o zastosowaniu sieci neuronowych w problemach klasyfikacyjnych.

EN

The article discusses the relationship between academic mathematics course and selected topics of machine learning. It shows how simple matrix operations help VOD services to recommend film titles consistent with the interests of users, based on their previous choices. A simplified version of the multiple regression algorithm used for real estate valuation is also presented and the use of neural networks in classification problems is mentioned.

12

Assessment of the influence of selected factors on the punctuality of an urban transport fleet

Grzelak Małgorzata, Borucka Anna, Świderski Andrzej

Transport Problems

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2020

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T. 15, z. 4, cz. 2

311--323

EN

Urban transport systems operate according to fixed, strict timetables, which requires high timeliness and technical readiness of the fleet. Therefore, this article proposes a detailed study of the punctuality of the public transport system using a multiple regression model for the main modes of transport (trams, buses, and Warsaw Metro). The analysis made it possible to go beyond the framework of the overall assessment and to identify the factors that have a significant effect on the punctuality index and to indicate the degree of this effect. The obtained results are a universal tool to assess the punctuality level of the urban transport fleet and to support decision making in the scope of organization of their work, which can be implemented in any similar transport system. The specification of the number of breakdowns, road accidents, or unauthorized stopping of a vehicle as the main causes of delays is the basis for taking corrective measures related to the improvement of the fleet operation system, or for preventive measures. The development of such models is practical in both public transport systems and similar companies providing transport services. For such institutions, the parameter of punctuality is extremely important and affects the quality of the services offered and the reputation of the company, which translates into the numer of customers and potential profit. Therefore, it is important to investigate the factors that shape the punctuality of the tasks performed. It allows for shaping the processes of fleet control and management. It is also worth emphasizing the scientific aspect of the publication, which is the presentation of the possibilities of applying selected mathematical models in such analyses, indication of the conditions of their application, and presentation of possible results together with their interpretation.

13

Assessment of the Simultaneous Influence of Yarn Linear Mass and the Real/Service Loading Cycle on the Fatigue Life of Smooth and Flame Cotton Yarns

Drobina Robert, Rysiński Jacek

Fibres & Textiles in Eastern Europe

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2020

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Vol. 28, no. 2 (140)

21--28

EN

In the paper, the results of fatigue investigations on smooth and flame yarns are presented. The investigations were performed for yarns of the following types 25, 30, 40 and 50 tex, i.e. for thin yarns as well as for relatively thick ones made in spinning mills. An assessment of fatigue life was made based upon statistically analysed Wöhler curves. Aiming for a more complex presentation of changes over time taking place due to variable loading, we performed an assessment of the simultaneous influence of linear mass changes for smooth and flame cotton yarns as well as coefficients of the real loading cycle on the fatigue life of adequate yarns (represented by the number of loading/fatigue cycles). A statistical approach to the identification of characteristics of fatigue life was utilised. Experimental data were approximated via linear-square polynomials. Additionally, factor analysis was performed, which has not been considered till now, in relation to the fatigue phenomena modelling. Due to the wide and comprehensive plan of experiments as well as the number of trails and specimens utilised, such investigations are rarely described in references. Within the framework of the experiment program, a consecutive series of planned tests: 4 x 8 based upon 32 variants for 20 tests were taken into consideration for smooth yarns of every variant as well as an adequate number of tests performed separately for cotton flame yarns. This allowed us to make versatile statistical analyses and reliable identification of needed quantities and parameters. Utilisation of a pre-designed (planned) experiment allows for assessment of the average behaviour of a product in a real technological process, while methods considering characteristics in dependence on one variable are too simple for showing the ongoing changes. They could not fully represent the behaviour of an artifact/product in service conditions.

PL

W artykule przedstawiono wyniki badań zmęczeniowych przędz Smooth i Flame. Badania przeprowadzono dla przędz następujących typów 25, 30, 40 i 50 tex, tj. dla cienkich przędz oraz stosunkowo grubych wykonanych w przędzalniach. Ocenę trwałości zmęczeniowej przeprowadzono na podstawie analizowanych statystycznie krzywych Wöhlera. Dążąc do bardziej złożonej prezentacji zmian zachodzących w czasie w wyniku zmiennego obciążenia, przeprowadziliśmy ocenę równoczesnego wpływu zmian masy liniowej dla bawełnianych przędz Smooth i Flame, a także współczynników rzeczywistego cyklu obciążania na żywotność zmęczeniową odpowiednich przędz (reprezentowane przez liczbę cykli obciążenia/zmęczenia). Zastosowano statystyczne podejście do identyfikacji charakterystyk trwałości zmęczeniowej. Dane eksperymentalne aproksymowano za pomocą wielomianów liniowo-kwadratowych. Dodatkowo przeprowadzono analizę czynnikową, której dotychczas nie rozważano, w odniesieniu do modelowania zjawisk zmęczeniowych. Ze względu na szeroki i kompleksowy plan eksperymentów, a także liczbę wykorzystanych szlaków i okazów, takie badania są rzadko opisywane w odnośnikach. W ramach programu eksperymentu wzięto pod uwagę kolejną serię planowanych testów: 4 x 8 w oparciu o 32 warianty dla 20 testów dla gładkich przędz każdego wariantu, a także odpowiednią liczbę testów wykonanych osobno dla przędz bawełnianych. To pozwoliło nam na wykonanie wszechstronnych analiz statystycznych i niezawodną identyfikację potrzebnych ilości i parametrów. Wykorzystanie wcześniej zaprojektowanego (planowanego) eksperymentu pozwala na ocenę średniego zachowania produktu w prawdziwym procesie technologicznym, podczas gdy metody uwzględniające cechy zależne od jednej zmiennej są zbyt proste do pokazania zachodzących zmian. Nie mogły w pełni przedstawić zachowania artefaktu/produktu w warunkach użytkowania.

14

Analog circuits specification driven testing by the means of digital stream and non-linear estimation model optimized evolutionarily

Golonek T., Chruszczyk Ł.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1283--1299

EN

The method described in this work allows to determine the optimal distribution of pulses of digital signal as well as the non-linear mathematical model based on a multiple regression statistical analysis, which are specialized to an effective and low-cost testing of functional parameters in analog electronic circuits. The aim of this concept is to simplify the process of analog circuit specification validation and minimize hardware implementation, time and memory requirements during the testing stage. This strategy requires simulations of the analyzed analog electronic circuit; however, this effort is done only once – before the testing stage. Then, validation of circuit specification can be obtained after a quick, very low-cost procedure without time consuming computations and without expensive external measuring equipment usage. The analyzed test signature is a time response of the analog circuit to the stream of digital pulses for which distributions were determined during evolutionary optimization cycles. Besides, evolutionary computations assure determination of the optimal form and size of the non-linear mathematical formula used to estimate specific functional parameters. Generally, the obtained mathematical model has a structure similar to the polynomial one with terms calculated by means of multiple regression procedure. However, a higher ordered polynomial usage makes it possible to reach non-linear estimation model that improves accuracy of circuit parametric identification. It should be noted that all the evolutionary calculations are made only at the before test stage and the main computational effort, for the analog circuit specification test design, is necessary only once. Such diagnosing system is fully synchronized by a global digital signal clock that precisely determines time points of the slopes of input excitation pulses as well as acquired output signature samples. Efficiency of the proposed technique is confirmed by results obtained for examples based on analog circuits used in previous (and other) publications as test benchmarks.

15

Cerchar abrasivity index prediction using multi-proxy data. A case study from the Sagdere Formation (Denizli Molasse Basin, Turkey)

Dogruoz Cihan

Archives of Mining Sciences

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2020

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Vol. 65, no. 4

787--801

EN

The prediction of rock cuttability to produce the lignite deposits in underground mining is important in excavation. Moreover, the certain geographic locations of rock masses for cuttability tests are also significant to apply and compare the rock cuttability parameters. In this study, sediment samples of two boreholes (Hole-1 and Hole-2) from the Sagdere Formation (Denizli Molasse Basin) were applied to find out the cerchar abrasivity index (CAI), rock quality designations (RQD), uniaxial compressive strengths, Brazilian tensile strengths and Shore hardnesses. The Sagdere Formation deposited in the terrestrial to shallow marine conditions consists mainly of conglomerates, sandstones, shales, lignites as well as reefal limestones coarse to fine grained. A dataset from the fine grained sediments (a part of the Sagdere Formation) have been created using rock parameters mentioned in the study. Dataset obtained were utilized to construct the best fitted statistical model for predicting CAI on the basis of multiple regression technique. Additionally, the relationships among the rock parameters were evaluated by fuzzy logic inference system whether the rock parameters used in the study can be correlated or not. When comparing the two statistical techniques, multiple regression method is more accurate and reliable than fuzzy logic inference method for the dataset in this study. Furthermore, CAI can be predicted by using UCS, BTS, SH and RQD values based on this study.

16

Costs of facade systems execution

Leśniak Agnieszka, Wieczorek Damian, Górka Monika

Archives of Civil Engineering

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2020

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Vol. 66, nr 1

81--95

EN

Cost estimation in the pre-design phase both for the contractor as well as the investor is an important aspect from the point of view of budget planning for a construction project. Constantly growing commercial market, especially the one of public utility constructions, makes the contractor, at the stage of development the design concept, initially estimate the cost of the facade, e.g. office buildings, commercial buildings, etc., which are most often implemented in the form of aluminum-glass facades or ventilated elevations. The valuation of facade systems is of an individual calculation nature, which makes the process complicated, time-consuming, and requiring a high cost estimation work. The authors suggest using a model for estimating the cost of facade systems with the use of statistical methods based on multiple and stepwise regression. The data base used to form statistical models is the result of quantitative-qualitative research of the design and cost documentation of completed public facilities. Basing on the obtained information, the factors that shape the costs of construction façade systems were identified; which then constitute the input variables to the suggested cost estimation models.

PL

Celem artykułu jest próba oszacowania kosztów wykonania systemów elewacyjnych obiektów użyteczności publicznej z wykorzystaniem modeli matematycznych, a w szczególności regresji wielorakiej oraz regresji krokowej postępującej. Dane użyte do budowy funkcji regresji zostały opracowane przez autorów na podstawie analizy dokumentacji projektowych, wykonawczych i kosztorysowych obiektów użyteczności publicznej. Opracowano bazę danych zawierającą główne czynniki wpływające na kształtowanie się kosztów wykonania systemów elewacyjnych obiektów użyteczności publicznej. Systemy elewacyjne realizowane były w formie fasad aluminiowo-szklanych oraz elewacji wentylowanych.

17

Modeling of transport processes in terms of seasonality of transport

Świderski Andrzej

Scientific Journal of Polish Naval Academy

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2019

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R. 60 nr 1 (216)

103--116

EN

The company’s success depends on many factors. One of them is the ability to meet the customers’ expectations and adjust to the needs reported by market. Mathematical methods and tools are helpful in assessing demand. Forecasts should take into account all factors shaping the demand for goods and services, but they are often difficult to define, not only because of their large number, but also due to the impact of individual variables, which is difficult to determine. In many cases, the number of placed orders strongly depends on the time at which they are submitted. The needs can vary according to the time of day, week and year. Then we are dealing with the so-called seasonality, the inclusion of which is very important in the company and enables to better adapt its activity to the customers’ requirements. This article describes the seasonality of demand in a company providing domestic and road transport services with high-tonnage vehicles. The validity of such analyses and potential benefits were indicated.

PL

Sukces przedsiębiorstwa zależy od wielu czynników. Jednym z nich jest zdolność do spełnienia oczekiwań klientów i dopasowanie do potrzeb zgłaszanych przez rynek. Pomocne w ocenie popytu są metody i narzędzia matematyczne. Formułowane prognozy powinny brać pod uwagę wszystkie czynniki kształtujące zapotrzebowanie na dobra i usługi, jednak często są one trudne do zdefiniowania, nie tylko ze względu na znaczną ich liczbę, ale również na trudny do określenia wpływ poszczególnych zmiennych. W wielu przypadkach liczba złożonych zamówień silnie zależy od czasu, w którym są one składane. Potrzeby mogą być zróżnicowane w zależności od pory dnia, tygodnia czy roku. Wówczas uaktywnia się tzw. sezonowość, której uwzględnienie jest bardzo istotne w przedsiębiorstwie i pozwala lepiej dostosować jego działalność do wymagań klientów. W artykule dokonano charakterystyki sezonowości popytu w firmie świadczącej usługi transportu krajowego drogowego realizowanego pojazdami wysokotonażowymi. Wskazano zasadność prowadzenia takich analiz i potencjalne korzyści.

18

Analiza popytu na usługi pływalni z wykorzystaniem modelu regresji wielorakiej

Pawlisiak Mieczysław

Gospodarka Materiałowa i Logistyka

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2019

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nr 2

28--36

PL

Organizacja służby ratowniczej na pływalniach obejmuje aspekty związane z gotowością do podjęcia skutecznych działań zapewniających bezpieczeństwo użytkownikom kąpieliska oraz skuteczną i szybką reakcję na sytuacje wypadkowe, zagrażające życiu i zdrowiu. Właściwy poziom tej gotowości zapewniony jest przede wszystkim poprzez wyszkolonych ratowników wodnych. Aby jednak w pełni mogli oni zrealizować powierzone im zadania, ich liczba musi być właściwa czyli odpowiednia do grupy osób korzystających z pływalni. Ponieważ ustawodawca zdefiniował jedynie minimalną liczbę ratowników wodnych przypadającą na dany rodzaj obiektu w artykule zaproponowano metodę szacowania potencjalnej liczby klientów w zależności od dnia tygodnia czy miesiąca kalendarzowego, jako wsparcie procesu dostosowywania poziomu bezpieczeństwa obiektu do liczby odwiedzających. W tym celu wykorzystano metodę regresji wielorakiej.

EN

The organization of swimming pool emergency service shall include aspects relating to the preparedness for taking effective measures in order to ensure the safety of users of the bathing water and to respond effectively and rapidly to accidental, life-threatening and health-threatening situations. An appropriate level of preparedness is primarily ensured by trained lifeguards. However, for them to be able to fully carry out entrusted tasks there must be an appropriate number of them, adapted to the group of people using swimming pool. Since the legislator defined only a minimum number of water rescuers per type of facility, this paper proposes a method of estimating the potential number of clients depending on the day of week and the calendar month, as a support for the process of adjusting the safety level at the swimming pool to the number of visitors. For this purpose, a multiple regression method was used.

19

Forecasting the demand for transport services on the example of a selected logistic operator

Grzelak Małgorzata, Borucka Anna, Buczyński Zbigniew

Archives of Transport

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2019

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Vol. 52, iss. 4

81--93

EN

The number of shipments is growing every year, and as a result, new transport companies arise. The increase in competition requires from entrepreneurs to apply solutions increasing the level of services provided in order to best satisfy the needs of the customers. In this aspect, minimizing the time of deliveries is extremely important, and it can be achieved, for example, by implementing the cross-docking method. It consists in consolidation of cargo from different shipment locations that is delivered in the same direction. The main feature of the above method is to keep the labor intensity of operations and the interference in the cargo to the minimum. The purpose of this article is to present a research on a logistic operator working based on a cross-docking warehouse with a capacity significantly lower than the average daily quantity of shipments handled. This requires both effective management of the available space and minimizing the time spent on manipulation activities. Therefore, it is important to know the expected number of parcels that are planned to be received and shipped on a given day in order to coordinate the work in the warehouse. It is possible to estimate it by using mathematical methods of forecasting. One of them - the multiple regression - is presented in this article. The calculations were made on the basis of collected empirical observations concerning orders for pallet spaces placed by customers. Such a forecast allows for improvement of the processes of planning and management of the possessed resources. It allows to adjust the number of warehouse workers or vehicles necessary for internal transport to the expected needs. Ultimately, it may translate into more efficient functioning not only of the surveyed branch, but also of the whole network.

20

The Influence of Border Rejections and Official Controls on the Market on Alert Notifications in the RASFF

Pigłowski M.

Zeszyty Naukowe Akademii Morskiej w Gdyni

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2018

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nr 106

7--22

EN

The Rapid Alert System for Food and Feed (RASFF) was created in 1979 and allows for quick response to risks for public health. Alert notifications within the RASFF are sent when the product, which presents a serious risk, is already on the market and a rapid action is required. The explicit increase of alert notifications can be noticed since 1999 and particularly since 2003/2004, when official controls on the market began to be noted. While a decrease of alert notifications can be observed since 2008, when border rejections in the RASFF began to be noted. The influence of border rejections and official controls on the market (as two variables) on the number of alert notifications in the RASFF in 1999-2014 was examined with regard to products categories, hazards categories and the European Union (EU) countries, using multiple regression. In the case of the EU countries also the influence of additional variables was examined: the number of food audits, import of food, drinks and tobacco, average total population and total agriculture production of food in the gross production value. The variable official controls on the market was statistically significant and the relationship was very high or high in case of: bivalve molluscs and products thereof, dietetic food, food supplements, fortified food, fish and fish products, herbs and spices and soups, broths, sauces and condiments (products categories) and: allergens, composition, food additives and flavourings, heavy metals, migration, mycotoxins and pathogenic micro-organism (hazards categories). The variable number of border rejections was statistically significant and the relationship was very high or high in case of: dietetic food, food supplements, fortified food (products categories) and: allergens, composition, food additives and flavourings and mycotoxins (hazards categories). In the case of the EU countries the very high or high relationship was not found in models with the two variables and was high in case of France and Latvia in models with six variables. It can be assumed that variability of the number of alert notifications in the RASFF (especially within the EU countries) also can depend on other factors, such as: the amount of food on the market, the scope of food control, the level of preparedness of controllers or movement of people. However, it is difficult to quantify these factors (and take as variables) or the adopted variables would cause collinearity.

PL

System Wczesnego Ostrzegania o Niebezpiecznej Żywności i Paszach (RASFF) powstał w 1979 roku. Umożliwia on szybkie reagowanie na zagrożenia dla zdrowia publicznego. Powiadomienia alarmowe w ramach systemu RASFF są przesyłane wówczas, gdy produkt prezentujący poważne ryzyko już znajduje się na rynku i konieczne jest natychmiastowe działanie. Wyraźny wzrost powiadomień alarmowych można zauważyć od roku 1999, a szczególnie od roku 2003/2004, kiedy zaczęto odnotowywać urzędowe kontrole na rynku. Natomiast spadek powiadomień alarmowych można zaobserwować od roku 2008, kiedy w systemie RASFF zaczęły być odnotowywane odrzucenia na granicy. Wpływ odrzuceń na granicy i urzędowych kontroli na rynku (jako dwóch zmiennych) na liczbę powiadomień alarmowych w systemie RASFF w latach 1999–2014 został zbadany w odniesieniu do kategorii produktów, kategorii zagrożeń i krajów Unii Europejskiej (UE), z wykorzystaniem regresji wielorakiej. W przypadku krajów UE zbadano także wpływ dodatkowych zmiennych: liczbę auditów żywności, import żywności, napojów i tytoniu, przeciętną populację całkowitą i całkowitą produkcję żywności w rolnictwie w produkcji brutto. Zmienna urzędowych kontroli na rynku była statystycznie istotna, a zależność bardzo wysoka lub wysoka w przypadku: małży i produktów pochodnych, żywności dietetycznej, suplementów diety, żywności wzbogaconej, ryb i produktów rybnych, ziół i przypraw korzennych, zup, bulionów, sosów i przypraw (kategorie produktów) oraz: alergenów, składu, dodatków do żywności i środków aromatyzujących, metali ciężkich, migracji, mykotoksyn i mikroorganizmów patogennych (kategorie zagrożeń). Zmienna odrzucenia na granicy była statystycznie istotna, a zależność bardzo wysoka lub wysoka w przypadku: żywności dietetycznej, suplementów diety, żywności wzbogaconej (kategorie produktów) oraz: alergenów, składu, dodatków do żywności i środków aromatyzujących i mykotoksyn (kategorie zagrożeń). W przypadku krajów UE zależność bardzo wysoka lub wysoka nie wystąpiła (w modelach z dwiema zmiennymi), jednak zależność wysoka wystąpiła w modelach z sześcioma zmiennymi w przypadku Francji i Łotwy. Zmienność liczby powiadomień alarmowych w systemie RASFF (szczególnie w ramach krajów UE) może także zależeć od innych czynników, jak np.: ilość żywności na rynku, zakres kontroli żywności, poziom przygotowania inspektorów czy ruch ludności. Jednak trudno byłoby skwantyfikować te czynniki (i przyjąć jako zmienne) lub też przyjęte zmienne powodowałyby współliniowość.