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Abstract

The article presents briefly several methods of working time estimation. However, three methods of task duration assessment have been selected to investigate working time in a real construction project using the data collected from observing workers laying terrazzo flooring in staircases. The first estimation has been done by calculating a normal and a triangular function. The next method, which is the focus of greatest attention here, is PERT. The article presents a way to standardize the results and the procedure algorithm allowing determination of the characteristic values for the method. Times to perform every singular component sub-task as well as the whole task have been defined for the collected data with the reliability level of 85%. The completion time of the same works has also been calculated with the use of the KNR. The obtained result is much higher than the actual time needed for execution of the task calculated with the use of the previous method. The authors argue that PERT is the best method of all three, because it takes into account the randomness of the entire task duration and it can be based on the actual execution time known from research.
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Abstract

Autor niniejszego artykułu postanowił zbadać skuteczność wykorzystania metod łączenia oraz selekcji klasyfikatorów w prognozowaniu upadłości przedsiębiorstw w Polsce. Przeprowadzone badanie pozwoliło na porównanie jakości stawianych prognoz przez cztery klasyfikatory indywidualne: liniowa analiza dyskryminacyjna, regresja logistyczna, sztuczna sieć neuronowa oraz las losowy z wynikami dziewięciu metod łączenia oraz selekcji, bazujących na zbiorze powyższych klasyfikatorów. Autor artykułu przeprowadził także analizę wpływu liczby uwzględnianych zmiennych na poprawność klasyfikacji poszczególnych metod.
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Abstract

The paper presents the statical research tests of rod bolt made of plastic with a length of 5.5 m, which were performed in a modern laboratory test facility at the Department of Underground Mining of the University of Science and Technology. Innovative The Self-excited Acoustic System (SAS) used to measure stress changes in the bolt support was characterized. The system can be used for the non-destructive evaluation of the strain of the bolt around the excavations as well as in tunnels. The aim of the study was to compare the re-sults recorded by two different measuring systems, thanks to which it will be possible to assess the load of long bolt support by means of the non-destructive method. The speed and simplicity of measurement, access to the sensors, accuracy of measurement and reading should be kept in mind in determining the load of rock bolt support . In addition, the possibility of damage to the sensor as a re-sult of technological or natural hazards should also be taken into account. In economic conditions, the „technical - balance laws of production”, which ex-cludes the use of load sensors on each bolt must be preserved. The use of indi-vidual load sensors of rock bolt support for the boundary state, allows appro-priate protection actions of the mining crew against sudden loss of excavation stability to be taken. The paper presents two basic effects used in the ultrasonic measurement sys-tem. The first result was the existence of stable limit cycle oscillations for posi-tive feedback. This effect is called the self-excited effect. The second effect is called the elasto-acoustic effect. It means that with the change of elastic stress-es in the material bring the change of the speed of propagation of the wave. In this connection, the propagation time between measuring heads is also changed. This effect manifests itself in the change in the oscillation frequency of the self-excited system. For this reason, by measuring the frequency of self-excited oscillation, it is possible to indirectly determine the level of effort of the tested material.
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Abstract

Due to the changing social and program expectations teachers more often look for new and better solutions in the field of education and teaching. Among many teaching methods, the storyline method is a very popular one and is gaining now more and more recognition from pedagogues around the world. The method starts to have its supporters in Poland as well. This article will be devoted to the description of this innovative strategy.
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Abstract

Niniejsza publikacja przedstawia metodykę DEA jako narzędzie do oceny efektywności technologii energetycznych. W pierwszej części pracy ukazano podstawowe narzędzia wykorzystywane do oceny portfela projektów inwestycyjnych w przemyśle energetycznym. W dalszej części scharakteryzowano metody Data Envelopment Analysis (DEA), czyli nieparametryczne procedury ustalania efektywności technologicznej badanych obiektów pod względem analizowanych czynników. W części praktycznej – wykorzystując analizę DEA – dokonano przykładowej oceny efektywności trzynastu technologii energetycznych, w tym technologii nadkrytycznego spalania węgla, zgazowania węgla połączonego z turbiną gazową oraz samodzielnego układu turbiny gazowej. Do analizy wykorzystano model nadefektywności nieradialnej z uwzględnieniem podziału na nakłady decyzyjne, niedecyzyjne oraz produkty pożądane i niepożądane. Dodatkowo przeprowadzona została analiza wyników dla przykładowej technologii. Zostały wytłumaczone możliwe sposoby interpretacji wyników końcowych z punktu widzenia obiektów efektywnych, jak i nieefektywnych. W tym drugim przypadku przedstawiono także kalkulację rozwiązania wzorcowego dla danej instalacji wraz z wnioskami co do skali działalności.
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Abstract

W opracowaniu podjęto po raz kolejny zagadnienie wyboru metody porządkowania liniowego jako odpowiedź na propozycję procedury przedstawionej w pracy Kisielińskiej (2016). Pokazano na dwóch przykładach, że ranking zależy od zastosowanej metody, a różnice są istotne. Podkreślono tym samym konieczność zastosowania kilku metod przed budową ostatecznego rankingu oraz wyeliminowaniu rankingów „odstających”. W artykule zaproponowano procedurę ich eliminacji. Oparto ją na średniej arytmetycznej i odchyleniu przeciętnym miar podobieństwa rankingów uzyskanych z wykorzystaniem kilku metod porządkowania liniowego. Z przedstawionych badań wynika, że dokonując wyboru metody porządkowania liniowego należy przeprowadzić obliczenia z zastosowaniem kilku procedur i dokonać wyboru wykorzystując już istniejące rozwiązania w literaturze lub zweryfikować z ekspertami badanej tematyki.
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Abstract

In this stud y, we attempt to analyse free nonlinear vibrations of buckling in laminated composite beams. Two new methods are applied to obtain the analytical solution of the nonlinear governing equation of the problem. The effects of different parameters on the ratio of nonlinear to linear natural frequencies of the beams are studied. These methods give us an agreement with numerical results for the whole range of the oscillation amplitude.
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Abstract

The problem of research undertaken in the article concerns the adaptation of traditional models of calculating the cost of capital to the specifics of mining companies. Solutions known from the literature do not give reasonable results. This is due to the uniqueness of the activities of mining companies, in which case we are dealing with a lack of reference to the typical market situations. The aim of this article is to identify solutions that allow rational and reliable results to be obtained. One of the proposals is a modified Fama-French method. The article was tested by calculating the cost of capital in the largest Polish mining enterprises. The problem of calculation of the cost of capital is particularly important in the area of assessing the effectiveness of investment projects. The cost of capital is used as the discount rate in dynamic measures of performance, such as NPV.
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Abstract

The purpose of this paper is to present and analyse the decision-making problem faced by a future house owner - selection of the optimal solution of building thermal insulation in relation to the selected criteria, both related to costs and future benefits. The problem of selecting the best solutions in the construction sector is widely discussed in the science literature. In this paper, the authors decided to solve the raised problem by using the Entropy method.
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Abstract

The paper present the concept of stability assessing the of solutions which are construction schedules. Rank have been obtained through the use of task scheduling rules and the application of the KASS software. The aim of the work is the choice of the equivalent solution in terms of the total time of the project. The selected solution optimization task should be characterized by the highest resistance to harmful environmental risk factors. To asses the stability of schedule simulation technique was used.
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Abstract

As a machining technology, welding can cause serious accidents by overloading or operation mistakes. Through analyzing the causes of various welding accidents, we found that the major cause for damage imposed after welding parts are loaded is the fracture of materials. Therefore, studying the influence of welding residual stress on the fracture property of materials is of great significance. This paper applied the digital image correlation technique to study the fracture property of welding parts under the influence of welding residual stress. In addition, standard parts and welding parts were selected to carry out a contrast experiment. Room temperature tensile tests were performed on both standard parts and test pieces after residual stress measurement. Using displacement field and strain field data obtained through VIC-2D software, the stress intensity factor around the crack tip of each specimen under the conditions of small load was calculated and corresponding analysis was carried out.
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Abstract

In the time of calling for a new evangelization in the Church as a result is at least the creation of the Papal Council for New Evangelization and the convoking of the XIII Ordi-nary Gathering of Bishops Synod under the watchword “New Evangelization for spreading the Christian faith“, one should be aware of the different types of evangelization. Only on this base can one point to the different aims of evangelization in the church connected with choosing the proper ways to carry it into effect. Speaking about three basic types, which are: missionary evangelization, pastoral evangelization and reevangelization or new evan-gelization one can speak about several basic methods of evangelization. You can describe it as a kerygmatic method, a missionary ministry method, bringing back to life faith for the members of the Church connected with self-evangelization and inculturation, a method connected precisely with pre-evangelization and new evangelization which should always have a joyful character.
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Abstract

Artykuł rozwija teoretyczny potencjał koncepcji trajektorii oraz wprowadza pojęcie trajektorii bezrobocia, jak również zwraca uwagę na wartość pamiętnikarskiego materiału badawczego. Dociekania bazują na dokumentach osobistych nadesłanych w wyniku konkursów na pamiętniki bezrobotnych – w 1931, 2000 i 2017 roku, które badamy za pomocą metody biograficznej, posiłkując się narzędziem do analizy jakościowej MAXQDA. Trajektorię definiujemy jako przebieg jakiegoś zjawiska i jego ewolucję w czasie, przede wszystkim pod wpływem silnego działania struktur i mechanizmów zewnętrznych, wobec których jednostka pozostaje w ograniczonym stopniu sprawcza. Natomiast w węższym rozumieniu traktujemy ją jako sekwencję przemian w życiu człowieka, wyznaczających zmiany statusu lub pozycji. Wychodzimy od logiki trzystopniowego schematu trajektorii – upadku, trwania oraz sukcesu, aby wskazać na znajdujące się „pomiędzy” nimi trajektoryjne typy. Położenie jednostki na trajektorii sugerujemy określać ze względu na dwie zmienne. Po pierwsze, status i związane z nim punkty zwrotne. Po drugie, Bourdieuowskie kapitały.
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics. Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points. Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.
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Abstract

The subject of the paper is the analysis of factors determining the value of multi-entity organizations in the energy sector and their ranking according to the degree of impact on this value. For this purpose, statistical methods were used, which are best suited to determine the order of diagnostic features according to a specific criterion. The survey covered companies from the Polish energy sector, while the process itself is based on aggregated data, which represents the financial data of capital groups currently operating in the Polish energy sector. The first part of the article presents a short description of the Polish energy sector, paying particular attention to the organizational structure of the sector, i.e. companies operating on the domestic energy market. The nature of a multi-entity enterprise as a typical economic unit in the sector is described. The second part of the article describes the assumptions of multidimensional comparative analysis (MCA) as a tool for comparing multifunctional units. The MCA makes it possible to find the most important parameters or indicators having the greatest impact on the value of a multi-entity organization, i.e. a capital group. The survey covered four companies from the Polish energy sector: TAURON Polska Energia SA, ENEA SA, ENERGA SA and PGE Polska Grupa Energetyczna SA. The study with the use of MCA was conducted in three stages: - in the first stage, on the basis of information contained in the financial statements, a matrix of diagnostic features was created, describing the financial condition of the examined entity, - in the second stage, the values of diagnostic variables were normalized/unified; two methods of normalization were applied: the method of standardization and zero unitization, - in the third stage, the diagnostic variables were grouped using two methods: the model measure of Hellwig’s development and the non-standard measure of development. The results of the analysis are illustrated by tables and figures.
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Abstract

Underground mining extraction causes the displacement and changes of stress fields in the surrounding rock mass. The determination of the changes is extremely important when the mining activity takes place in the proximity of post-flotation tailing ponds, which may affect the stability of the tailing dams. The deterministic modeling based on principles of continuum mechanics with the use of numerical methods, e.g. finite element method (FEM) should be used in all problems of predicting rock mass displacements and changes of stress field, particularly in cases of complex geology and complex mining methods. The accuracy of FEM solutions depends mainly on the quality of geomechanical parameters of the geological strata. The parameters, e.g. young modulus of elasticity, may require verification through a comparison with measured surface deformations using geodetic methods. This paper presents application of FEM in predicting effects of underground mining on the surface displacements in the area of the KGHM safety pillar of the tailing pond of the OUOW Żelazny Most. The area has been affected by room and pillar mining with roof bending in the years 2008-2016 and will be further exposed to room-and-pillar extraction with hydraulic filling in the years 2017–2019.
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Abstract

Cel artykułu to pokazanie, że badania z zakresu socjologii cyfrowej są ważnym uzupełnieniem większości projektów badań społecznych oraz wprowadzenie systematyzacji pojęciowej. Omawiam różnice znaczeniowe i kategoryzacyjne pojęć. Przedstawiam podstawowe zalety badań ilościowych i Big Data, argumentując, że pełne ich wykorzystanie jest możliwe przede wszystkim dzięki uzupełnieniu badań ilościowych o thick data pochodzące z pogłębionych badań jakościowych. Postuluję, że dostęp do Big Data w większym stopniu wymusza umiejętną triangulację metodyczną i stosowanie etnografii cyfrowej. Twierdzę również, że socjologia w niedalekiej przyszłości będzie musiała nie tylko uwzględniać badania społeczności internetowych w niemal każdym projekcie badawczym, oraz nie tylko wchłonąć znaczną część warsztatu badawczego z zakresu analizy danych rozwiniętego w naukach ścisłych, ale także wypracować metody łączenia Big Data z etnografią cyfrową.
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Abstract

On the 14th of February, 2015, a huge fire broke out on Łazienkowski Bridge; a five span bridge, 423 m long and 28 m wide, built in the years 1972-74. It was a fully steel structure with four plate girders and orthotropic deck. The fire started under the first span during the replacement of wooden service decks. The next day, the Department of Bridges of the Warsaw University of Technology was designated to conduct an expertise material investigation, geometrical verification, and FEM model analysis. The subject of this paper concentrates on geometrical issues. The main difficulty of this task was the lack of full reference data regarding the bridge's original structure. The old design was incomplete and there was no actual surveying results for the undamaged structure. As a conclusion, some remarks focused on surveying measurements and on the final decision regarding this bridge are given. It was eventually exchanged into a brand new one and put into public use on the 28th of October, 2015.
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Abstract

This paper addresses the tensile and flexural strength of HPC (high performance concrete). The aim of the paper is to analyse the efficiency of models proposed in different codes. In particular, three design procedures from: the ACI 318 [1], Eurocode 2 [2] and the Model Code 2010 [3] are considered. The associations between design tensile strength of concrete obtained from these three codes and compressive strength are compared with experimental results of tensile strength and flexural strength by statistical tools. Experimental results of tensile strength were obtained in the splitting test. Based on this comparison, conclusions are drawn according to the fit between the design methods and the test data. The comparison shows that tensile strength and flexural strength of HPC depend on more influential factors and not only compressive strength.
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Abstract

The model concept, as presented in this paper, is an original solution created by the author, and can be used as a proposal to build an innovative mechanism to increase the effectiveness of programming and implementation of the development policy, and improve the quality of functioning of a building research institute. The development management system included in this model is a set of actions targeting at the effective use of human and tangible resources, undertaken in a coordinated manner and leading to the achievement of previously established objectives. The market activity of building research institutes is directly or indirectly involved in construction projects, which translates into market mechanisms, such as innovation and competitiveness. In addition, it indicates the participation of a building research institute in the engineering of construction projects as a key to entrepreneurship and implementations.
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Abstract

Laplace Transform is often used in solving the free vibration problems of structural beams. In existing research, there are two types of simplified models of continuous beam placement. The first is to regard the continuous beam as a single-span beam, the middle bearing of which is replaced by the bearing reaction force; the second is to divide the continuous beam into several simply supported beams, with the bending moment of the continuous beam at the middle bearing considered as the external force. Research shows that the second simplified model is incorrect, and the frequency equation derived from the first simplified model contains multiple expressions which might not be equivalent to each other. This paper specifies the application method of Laplace Transform in solving the free vibration problems of continuous beams, having great significance in the proper use of the transform method.
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Abstract

Zasadniczym celem artykułu jest przedstawienie rekonstrukcji, krytyki i reinterpretacji jednej z metod konstrukcyjnych zastosowanych przez Leszka Nowaka do budowy negatywistycznej metafizyki unitarnej. Twierdzenie Nowaka, że podstawową stosowaną przez niego metodą jest metoda idealizacji i konkretyzacji, nie da się utrzymać z następujących powodów: postulowana przez Nowaka struktura doktryn metafizycznych jest niezgodna z procedurą konkretyzacji na gruncie metafizyki unitarnej, sekwencja modeli jest w kilku przypadkach dowolna, kolejność wprowadzanych do koncepcji pojęć jest do pewnego stopnia dowolna oraz stosowana metoda nie prowadzi do zmniejszenia stopnia spekulatywności systemu. Ze swej strony proponuję uznać powyższą metodę za metodę abstrakcji i odabstrakcyjniania, i scharakteryzować odmienny sposób rozumienia metody idealizacji i konkretyzacji. W wyniku tych zabiegów zawartość Bytu i myśli uznana zostaje za spekulatywny pierwszy model metafizyki negatywistycznej
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Abstract

The basic element of a project organizing construction works is a schedule. The preparation of the data necessary to specify the timings of the construction completion as indicated in the schedule involves information that is uncertain and hard to quantify. The article presents the methods of building a schedule which includes a fuzzy amount of labour, time standards and number of workers. The proposed procedure allows determining the real deadline for project completion, taking into account variable factors affecting the duration of the individual works.
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Abstract

The paper presents a certain way which determines the critical buckling force for a micro-heterogeneous FGM plate band. A stiffness matrix of an individual cell of such band, different for various cells, has been determined. The obtained matrix can also be treated as a variable stiffness matrix of a “superelement” in the Finite Element Method. A computational algorithm for the critical force as well as the way of testing of its correctness has also been presented. The results obtained for various support conditions have been compared to the values known from the literature. The influence of the number of cells on the critical buckling force has been investigated.
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