Civil engineering is one of the many fields of occurrences of uncertain parameters. The present paper in an attempt to present and describe the most common methods used for inclusions of uncertain parameters . These methods can be applied in the area of civil engineering as well as for a larger domain. Definitions and short explanations of methods based on probability, interval analysis, fuzzy sets, and convex sets are presented. Selected advantages, disadvantages, and the most common fields of implementation are indicated.
An example of a cantilever beam presented in this paper shows the main differences between the methods. Results of the performed analysis indicate that the use of convex sets allows us to obtain an accuracy of results similar to stochastic models. At the same time, the computational speed characteristic for interval methods is maintained.
Positively invariant sets play an important role in the theory and applications of dynamical systems. The stability in the sense of Lyapunov of the equilibrium x = 0 is equivalent to the existence of the ellipsoidal positively invariant sets. The constraints on the state and control vectors of dynamical systems can be formulated as polyhedral positively invariant sets in practical engineering problems. Numerical checking method of positive invariance of polyhedral sets is addressed in this paper. The validation of the positively invariant sets can be done by solving LPs which can be easily done numerically. It is illustrated by examples that our checking method is effective. Compared with the now existing algebraic methods, numerical checking method is an attractive method in that it’s easy to be implemented.
The article outlines how to use the convergence of collections to determine the position of a mobile device based on the WiFi radio signal strength with the use of fuzzy sets. The main aim is the development of the method for indoor position determination based on existing WiFi network infrastructure indoors. The approach is based on the WiFi radio infrastructure existing inside the buildings and requires operating mobile devices such as smartphones or tablets. An SQL database engine is also necessary as a widespread data interface. The SQL approach is not limited to the determination of the position but also to the creation of maps in which the system dening the position of the mobile device will operate. In addition, implementation issues are presented along with the distribution of the burden of performing calculations and the benets of such an approach for determining the location. The authors describe how to decompose the task of determining the position in a client-server architecture.
The article presents the results of the second part of an eye-tracking study conducted on Polish secondary school students working with a textbook for learning English. 20 dyslexic and 20 non- dyslexic school students worked with two sets of materials that had different graphic layouts but the same content. Their eye movements were recorded. The analysed data show that the arrangement of the material and images on the textbook page influence both the way the students (especially dyslexic ones) work with the book and their results.
A group of old apartment houses with the age over 100 years (that is those carried out before the First World War) takes an important place in polish building resources. Technical maintenance of apartment houses, traditional methods erected, is nowadays and will be a valid problem in the nearest future. The results of the work refer to the general population, estimated for 600 objects, that is about 20% of municipal downtown apartment houses in Wrocław.
The purpose of the research was to identify an influence of widely considered maintenance of apartment houses on a degree and intensity of their elements’ deterioration. The goal of the work has been fulfilled by symptoms’ analysis of declining of inspected elements’ exploitation values, that is identification of mechanics of their defects arising.
The range of the work has required creation of original qualitative model of pinpointed defects and its transfer into quantitative one. It has made possible to analyse the reason - effect phenomena „defect - technical wear” relevant to the most important elements of Wroclaw downtown district’s apartment houses. The research procedure has been conducted in accordance of fuzzy sets theory which made possible to describe qualitative model of pinpointed defects and its transfer into a quantitative one.
In this paper, we randomly select 75 sets data of calcium sulfate hemihydrate (CSH) content and initial setting time, and the traditional test method of CSH and analyses initial setting time was used by complexometric titration. So the close relationship between them was studied in depth, which classification fitting data to be analyzed by regression analysis. The result shows that this regression analysis method can accurately determine CSH content in modified industrial by-product gypsum. The determination method has the advantages of simplification and rapid operation. As well as, the XRF quantitative analytical method was used to test the CSH content, which verified the accuracy of regression analysis method. The results also show that this method has high accuracy, and can simplify the traditional experimental process. The method developed is easier and more convenient and has broad prospects in application.
The problem of setting out in civil engineering applications has been addressed in the literature for a long time. However, technological development has provided researchers with an opportunity of having other procedures in line with modern techniques in surveying sciences. One of the most important procedures in erecting steel structures, bridges, and precast columns of a building is the accurate placement of the anchorage system in concrete. The traditional method for staking out anchor bolts relies on sight rails, string lines, and tape measure. The precision of this art depends not only on the accuracy of observed offset distances during layout operations but also on the centerline of the anchoring template itself. Nowadays, the process of designing structures is executed using software that can perform a digital plan in CAD environment, where the coordinates of each anchor bolt can be defined. This research presents an accurate approach of positioning anchor bolts based on the second problem in surveying and total station. Error analysis and field application are described to evaluate the performance of the proposed method. However, the results indicate that the developed technique increases productivity, reduces the cost, and improves the positional accuracy.
Works connected with execution of geodesic and photogrammetric surveys and with setting up maps in the scale of 1:5000 of environs of the Polish Polar Station on the Isbjörnhamna Bay and in the scale of 1:500 of the area covered with buildings of the Station are discussed.
Two formal types of models of living processes, especially evolutionary ones, may be distinguished: the well-known mathematical type and the less-known logical one. The latter applies the terms “class” or “set”; both the terms are understood either in a collective sense (in mereology) or in a distributive sense (in set theory). These formal terms may be used among others to such organic multiplicities as populations or species of organisms, and to organic constituents (molecules, cells, organs) of living organism. Collective concepts refer to objects existing in nature, whereas distributive concepts refer to the linguistic and research constructions of models of natural objects, developed to cognitively grasp natural regularities.
Overseas mining investment generally faces considerable risk due to a variety of complex risk factors. Therefore, indexes are often based on conditions of uncertainty and cannot be fully quantified. Guided by set pair analysis (SPA) theory, this study constructs a risk evaluation index system based on an analysis of the risk factors of overseas mining investment and determines the weights of factors using entropy weighting methods. In addition, this study constructs an identity-discrepancycontrary risk assessment model based on the 5-element connection number. Both the certainty and uncertainty of the various risks are treated uniformly in this model and it is possible to mathematically describe and quantitatively express complex system decisions to evaluate projects. Overseas mining investment risk and its changing trends are synthetically evaluated by calculating the adjacent connection number and analyzing the set pair potential. Using an actual overseas mining investment project as an example, the risk of overseas mining investment can be separated into five categories according to the risk field, and then the evaluation model is quantified and specific risk assessment results are obtained. Compared to the field investigation, the practicability and effectiveness of the evaluation method are illustrated. This new model combines static and dynamic factors and qualitative and quantitative information, which improves the reliability and accuracy of risk evaluation. Furthermore, this evaluation method can also be applied to other similar evaluations and has a certain scalability.
The paper presents the experience of using the ŁPrP, ŁPKO, ŁPSp, ŁPSpA i ŁPSp3R types of flattened supports for longwall entries in the conditions of the JSW S.A. Knurów-Szczygłowice coal mine. The article concentrates on the support solutions applied in the conditions of the mine and the results in terms of stability and usefulness of the structures of the supports. An analysis of the load bearing capacity and technological conditions has been conducted for various flattened supports solutions, with special consideration given to the ŁPSp and ŁPrPJ support sets. Comparing these two, the ŁPSp exhibits a load bearing capacity that is 21% higher while using 31% less steel mass. The experiment results allowed to determine that the ŁPSpA and ŁPSp3R support types are an advantageous solutions in case of longwall set-up rooms.
Theoretical and experimental research indicates that radial loads have a significant influence on the value of belt-on-idler rolling resistances. Computational models discussed in literature use the notion of unit rolling resistance, i.e. rolling resistance per unit length of the idler. The total value of the rolling resistance of belt on a single idler is determined by integrating unit rolling resistance with respect to the length of the contact zone between the belt and the idler. This procedure requires the knowledge of normal load distribution along the contact zone between the belt and the idler. Loads acting on the idler set have been the object of both theoretical analyses and laboratory tests. Literature mentions several models which describe the distribution of normal loads along the contact zone between the belt and the idler set (Krause & Hettler, 1974; Lodewijks, 1996; Gładysiewicz, 2003; Jennings, 2014). Numerous experimental tests (Gładysiewicz & Kisielewski, 2017; Król, 2017; Król & Zombroń, 2012) demonstrated that the resultant normal loads acting on idlers are approximate to the loads calculated in theoretical models. If the resultant normal load is known, it is possible to assume the distribution of loads acting along the contact zone between the belt and the idler. This paper analyzes various hypothetical load distributions calculated for both the center idler roll and for the side idler roll. It also presents the results of calculations of belt rolling resistances for the analyzed distributions. In addition, it presents the results of calculations with allowance for load distribution along the generating line of the idler.
The basis for a mineral deposit delimitation is a qualitative and quantitative assessment of deposit parameters, qualifying a deposit as an economically valuable object. A conventional approach to the mineral deposit recognition and a deposit detailed parameters qualification in the initial stages of development work in the KGHM were presented in the paper. The goals of such recognition were defined, which through a gradual detailed expansion, resulting from the information inflow, allows for the construction of a more complete decision-making model. The description of the deposit parameters proposed in the article in the context of fuzzy logic, enables a presentation of imprecise statements and data, which may be a complement to a traditional description. Selected non-adjustable and adjustable s-norm and t-norm operators were demonstrated. Operators effects were tested for selected ore quality parameters (copper content and deposit thickness) by constructing adequate membership functions. In a practical application, the use of chosen fuzzy logic operators is proposed for the assessment of the qualitative parameters of copper-silver ore in the exploitation blocks for one of the mines belonging to KGHM Polish Copper S.A. The considerations have been extended by including the possibility of using compensation operators.
In this paper the new synthesis method for reversible networks is proposed. The method is suitable to generate optimal circuits. The examples will be shown for three variables reversible functions but the method is scalable to larger number of variables. The algorithm could be easily implemented with high speed execution and without big consuming storage software. Section 1 contains general concepts about the reversible functions. In Section 2 there are presented various descriptions of reversible functions. One of them is the description using partitions. In Section 3 there are introduced the cascade of the reversible gates as the target of the synthesis algorithm. In order to achieve this target the definitions of the rest and remain functions will be helpful. Section 4 contains the proposed algorithm. There is introduced a classification of minterms distribution for a given function. To select the successive gates in the cascade the condition of the improvement the minterms distribution must be fulfilled. Section 4 describes the algorithm how to improve the minterms distributions in order to find the optimal cascade. Section 5 shows the one example of this algorithm.
Sound intensity measurements using special sensors in a form of pressure-velocity and pressure-pressure probes are becoming more and more often the method of choice for characterization of sound sources. Its wider usability is blocked by the probes’ costs. This paper is on a possible modification of the well-known pressure-pressure sound intensity measurement method. In the proposed new approach a synchronized measurement procedure using only single microphone is used. The paper presents the basics of the sound intensity theory, a review of currently usedmethods of intensity measurement and requirements and limitations of the new method. In the proposed approach one microphone and a properly designed positioning system is used. The application of the method to study the directional characteristics of an active loudspeaker system have been described in detail. The obtained results were compared with those of measurements performed with a commercial p–u probe. The paper contains conclusions indicating advantages of the applied method in comparison with standard pressure measurement methods.