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EN
The paper deals with the design of equipment for verification and calibration of axle and crane weighing instruments. In its introduction, it discusses the basic concepts of axle and crane weighing instruments, their calibration, and verification. The paper briefly describes the original technical design solution used in the calibration and verification of these weighing instruments. Subsequently, the article describes the legislative, technical and functional requirements for metrological equipment being developed. The paper presents two design solutions for handling calibration weights. In both solutions, the construction and individual functional parts of the equipment are described. Both of these solutions were designed and tested in practical measurements in the Laboratory for Testing of Weighing Instruments of the Slovak Legal Metrology n.o. Finally, the paper presents the results of the development of a new measuring system at the University of Žilina.
EN
In this paper, the results of modeling of the burning process in the piston engines whose working process is realized on the basis of various conceptual approaches are presented: in diesel with direct injection of the fuel; in a gas engine with spark ignition; and in a two-fuel engine (in the gas-diesel), where the mixture of natural gas and air ignites with the help of the fuse dose of the diesel fuel. The models of burning based on the different in-principle approaches are analyzed and used. Verification of the models is performed by a comparison of the results of modeling with the experimental diagrams. The specific values of the empirical coefficients, used in modeling of the burning proces in the engines under study, are determined. The practical recommendations on the choice of the burning model depending on the working process conception are given.
PL
W erze cyfrowej jednym z popularnych źródeł szukania informacji stał się Internet. Zamieszczane tam informacje nie zawsze są wiarygodne. Celem artykułu jest określenie, w jakim stopniu odbiorcy weryfikują wiarygodność informacji znalezionych w Internecie, a także scharakteryzowanie kryteriów pomocnych przy ocenie ich wiarygodności. Realizacja celu opierała się na analizie literatury przedmiotu oraz raportów poświęconych zagadnieniom korzystania z Internetu. W artykule zamieszczono m.in. charakterystykę atrybutów informacji składających się na jej jakość, ponieważ stanowią one główne wyznaczniki przy określaniu kryteriów oceny informacji. Tematyka jest o tyle ważna, że świadomość oraz wiedza internautów, w jaki sposób korzystać z informacji zamieszczanych w Internecie, może zabezpieczać przed cyberatakami oraz ułatwiać podejmowanie decyzji i kształtować odpowiednie zachowanie. Literatura przedmiotu i tutoriale dostarczają wskazówek pomagających ocenić jakość informacji, ale jak wynika z badań, użytkownicy Internetu rzadko świadomie weryfikują prezentowane tam treści. Pewną trudnością jest też ustalenie, na ile cecha, jaką jest wiarygodność informacji, może być wystarczająca przy podejmowaniu decyzji.
EN
In the digital era, the Internet has become one of the popular sources of searching for information. The information contained therein is not always reliable. The aim of the article was to determine to what extent the recipients verify the credibility of information posted on the Internet and to characterize the criteria helpful in assessing the credibility of information posted on the Internet. The implementation of the goal was based on the analysis of the literature on the subject and reports on the use of the Internet. The article includes, among others characteristics of the information attributes that make up its quality, as they are the main determinants in determining the criteria for evaluating information. The subject matter is so important that the awareness and knowledge of Internet users on how to use information posted on the Internet may protect against cyber attacks and facilitate decision-making and appropriate behavior. The literature on the subject and tutorials provide guidelines to help assess the quality of information, but research has shown that Internet users rarely consciously verify the content presented there. It is also difficult to determine to what extent the quality of information credibility may be sufficient when making decisions.
PL
Scharakteryzowano zagadnienia związane z oceną nośności elementów ściskanych i zginanych eurokodową metodą ogólną. Omówiono kwestie związane z efektami wpływającymi na sprężysty stan krytyczny elementów ściskanych i zginanych. Przedstawiono ogólną zależność stanu krytycznego, która pozwala na bardziej ekonomiczne projektowanie elementów stalowych o przekrojach szerokostopowych. Zamieszczono jej zastosowanie w ocenie nośności prętów realnych. Podano wnioski praktyczne dotyczące normowej weryfikacji nośności wyboczeniowej.
EN
Problems related to the evaluation of beam-column resistance with the use of Eurocode's General Method are dealt with in this paper. Issues related to effects influencing the elastic critical state of beam-columns are discussed. The general relationship for the critical state is presented that allows for more economical design of steel elements of wide flange sections. Its application in the resistance evaluation of real members is presented. Practical conclusions are drawn with regard to codified verification of the buckling resistance.
EN
The Core Network Algebra (CNA) is a model for concurrency that extends the point-to-point communication discipline of Milner’s CCS with multiparty interactions. Links are used to build chains describing how information flows among the different agents participating in a multiparty interaction. The inherent non-determinism in deciding both the number of participants in an interaction, and how they synchronize, makes it difficult to devise verification techniques for this language. We propose a symbolic semantics and a symbolic bisimulation for CNA which are more amenable for automating reasoning. Unlike the operational semantics of CNA, the symbolic semantics is finitely branching and it represents, compactly, a possibly infinite number of transitions. We give necessary and sufficient conditions to efficiently check the validity of symbolic configurations. We also propose the Symbolic Link Modal Logic, a seamless extension of the Hennessy-Milner logic which is able to characterize the (symbolic) transitions of CNA processes. Finally, we specify both the symbolic semantics and the modal logic as an executable rewriting theory. We thus obtain several verification procedures to analyze CNA processes.
EN
Static type systems are usually not sufficient to express all requirements on function calls. Hence, contracts with pre- and postconditions can be used to express more complex constraints on operations. Contracts can be checked at run time to ensure that operations are only invoked with reasonable arguments and return intended results. Although such dynamic contract checking provides more reliable program execution, it requires execution time and could lead to program crashes that might be detected with more advanced methods at compile time. To improve this situation for declarative languages, we present an approach to combine static and dynamic contract checking for the functional logic language Curry. Based on a formal model of contract checking for functional logic programming, we propose an automatic method to verify contracts at compile time. If a contract is successfully verified, it can be omitted from dynamic checking. This method decreases execution time without degrading reliable program execution. In the best case, when all contracts are statically verified, it provides trust in the software since crashes due to contract violations cannot occur during program execution.
PL
W artykule przedstawiono wymagania norm odnoszące się do charakterystyki czasowo-prądowej wyłączników różnicowoprądowych o znamionowym prądzie różnicowym zadziałania równym 30 mA. Zaprezentowano wyniki badań laboratoryjnych czasu wyłączania takich wyłączników przy sinusoidalnym prądzie różnicowym i oceniono je z punktu widzenia tych wymagań. Badania wykazały, że czasy wyłączania dwóch lub większej liczby porównywanych wyłączników różnicowoprądowych mogą się znacznie różnić. W przypadku niektórych wyłączników duże różnice w tych czasach wystąpiły dla danego wyłącznika w kolejnych próbach prądem o takich samych parametrach. Jednak jest to zjawisko normalne i nie powinno być podstawą do negatywnej oceny stanu wyłącznika różnicowoprądowego, o ile nie są przekroczone dopuszczalne czasy określone w normie.
EN
The requirements of the standards regarding the time-current curve of residual current devices (RCDs) with a rated residual operating current of 30 mA are presented. The results of laboratory tests of the break time of such protection devices under sinusoidal current are discussed as well as evaluated from the point of view of the provisions of the standards. The presented studies have shown that break times of two or more compared RCDs can vary significantly. In the case of some devices, high differences in break times occurred for a given device in subsequent trials with the current waveform of the same parameters. However, this is normal behavior of RCDs and it should not be the reason for a negative assessment of the condition of the RCD, unless the permissible times specified in the standard are exceeded.
PL
W pracy analizie poddano wyniki badań przyczepności cementowych zapraw klejących do płytek ceramicznych wykonanych na zlecenie organów nadzoru budowlanego w latach 2016-2020. Znaczna ilość zbadanych cementowych zapraw klejących nie spełniła kryterium odbiorczego i zgodnie z regulacjami prawnymi ich producent zobowiązany był do niezwłocznego wycofania wyrobu z rynku. Przy ocenie zgodności wyników z kryteriami stosowana jest reguła prostej akceptacji, co oznacza, że wyrób został uznany za zgodny lub niezgodny w odniesieniu do wyniku, jeśli wynik ten, bez uwzględnienia zmienności wynikającej z niepewności pomiarowej, spełnił bądź nie spełnił wymagań progowych. Omówiono możliwe sytuacje, w których producent dokonał prawidłowej oceny i weryfikacji stałości właściwości użytkowych [AVCP] cementowej zaprawy klejącej, zaś ocena laboratorium była negatywna z powodu nie uwzględnienia zmienności wynikającej z niepewności pomiarowej lub specyfiki wieloetapowej metody badawczej. Analizę wyników badań przeprowadzono według podziału na cementowe zaprawy klejące klasy C1 i C2 oraz według podziału na laboratoria notyfikowane, w których wykonane zostały badania. Analizując proporcje pomiędzy wyrobami spełniającymi i niespełniającymi wymagań w dwóch laboratoriach wykonujących badania na zlecenie organów nadzoru budowlanego, stwierdzono duże różnice pomiędzy nimi.
EN
The paper analyzes the results of adhesion tests of cementitious adhesives to ceramic tiles, commissioned by construction supervision authorities in 2016-2020. A significant number of the tested cementitious adhesives did not meet the acceptance criteria. Following legal regulations, their manufacturer was obliged to withdraw the product from the market immediately. When assessing the compliance of the results with the requirements, the simple acceptance rule is applied. It means that the product is considered compliant only if the result met the threshold requirements. The results variability estimated from the measurement uncertainty is not taken under consideration. Possible situations in which the manufacturer correctly assessed and verified the constancy of performance [AVCP] of the cementitious adhesive, but the laboratory assessment was negative due to not including the variability resulting from measurement uncertainty, or the specificity of the multi-stage research methodology were discussed. The analysis of the test results was carried out according to the division into C1 and C2 class cementitious adhesives, and also according to the division into notified laboratories, where the tests were performed. When analyzing the number of products that meet or not the requirements, significant differences were found between laboratories carrying out tests commissioned by construction supervision authorities.
EN
The instability of the real structure of a firm is one of the fundamental problems in simulating microeconomic systems. This paper proposes a method, called ACV (abstraction – gradual concretization – verification) for constructing a flexible simulation model of a corporation. This method is based on the assumption that an effective approach to simulating a microeconomic system should take into account the structural instability of the modelled object. Practical implementation of the ACV method is illustrated using the EK_AN simulator of a firm. The purpose of the simulator as a scientific tool of operations research is to analyse the relations of given inputs (decisions) with the short- and mediumterm forecasts of a firm’s economic performance.
PL
W artykule przedstawiono studium przypadku weryfikacji poprawności wyników obliczeń generowanych przez model numeryczny rzeczywistej sieci kanalizacji sanitarnej. Do budowy modelu wykorzystano program SWMM 5.0. Badaniom poddano sieć podmiejską, której łączna długość przewodów, bez przykanalików, wynosi ok. 11 km. Sieć wyposażona jest w 8 przepompowni. Praca 4 spośród nich jest monitorowana: łączny czas pracy pomp oraz poziom napełnienia zbiorników. Zebrane dane z monitoringu stanowiły podstawę przeprowadzenia tytułowej weryfikacji wyników modelowych.
EN
In the article a case study of verification of calculation results generated by the numerical model of the existing sanitary sewage network has been presented. The numerical model was built using SWMM 5.0 software. The suburban network with the total length of approximately 11 km (without connections), was investigated. The network is equipped with 8 pumping stations. The total pump operation time and the tank filling level are monitored for the four pumping stations. The basis for verification of the model results was the monitoring data collected.
11
Content available Walidacja a weryfikacja metody pomiarowej
PL
Procedury walidacji i weryfikacji laboratoriów badawczych powinny być zgodne z wymogami prawnymi ujętymi w normach. Każde laboratorium badawcze musi dołożyć starań, aby badania i pomiary były wykonywane rzetelnie, zgodnie z aktualnym stanem wiedzy. W artykule przedstawiono wymogi norm, które dane laboratorium powinno przestrzegać.
EN
There are many indicators of the "quality" of laboratory tests confirming the competence of laboratory staff as well as the technologies used. Validation is the process of monitoring a test, procedure or method. It proves that the laboratory controls the method and gives reliable results. Verification, whereas, is a one-off process, carried out to establish or confirm the expected performance of the test before applying it in the lab. Verification means checking the test in a given laboratory. The laboratory, while testing a given product, should be sure of the results obtained. Its duty is to confirm laboratory staff competences and ensure the recipient of the results that the measurements methods are appropriate. The use of welldescribed and tested methods does not automatically give a guarantee of obtaining reliable results. Therefore, the laboratory should control the quality of performed tests in order to be able to prove that it is able to meet the acceptance criteria described in the methods used by it.
EN
The aim of the research presented in this paper was to solve one of the fundamental problems of modelling and simulation, i.e., verification of a model as a scientific tool of operations research. To attack this problem, certain crucial issues in the philosophy of science (the demarcation problem, the principle of verifiability) must be redefined. In discussing the question of verification, a procedure (the so called RAD-VER procedure) for verifying a model of a microeconomic system, in our case – a firm, is formulated. It is assumed that verification is a ceaseless process of evaluating a model’s scientificity from the standpoints of deductive reasoning, coherency and empiricism. Verification has been divided into two stages: the verification of the assumptions underlying the model of a firm and the verification of the simulator.
EN
Agility is a concept and practice with significant importance in managing and leading added value in products, services, projects, and organizations, although it’s usage can also be very risky due to its degree of fuzziness, if not properly understood and defined. This research re-defines agility, emphasizes the need for ontologies for its management and leadership applications and uses a new type of fuzzy logic-based software to measure the degree of agility inside a technology company. In our agility research, various definitions of agility were first gathered and presented for the creation of an agility ontology through a mind map, revealing the main characteristics of agility. Then as part of the Co-Evolute theory and methodology, the first agility ontology was developed as well as the first software application that evaluates the degree of agility in an organization. The application includes statements on which the respondents give opinions in their situation concerning the current and future desired states of agility and its importance in an evaluative way. Today the application has been fully tested in the real world and we have obtained the first test results. The positive verification and validation of the method are shown in this article.
EN
Diagnosability and opacity are two well-studied problems in discrete-event systems. We revisit these two problems with respect to expressiveness and complexity issues. We first relate different notions of diagnosability and opacity. We consider in particular fairness issues and extend the definition of Germanos et al. [ACM TECS, 2015] of weakly fair diagnosability for safe Petri nets to general Petri nets and to opacity questions. Second, we provide a global picture of complexity results for the verification of diagnosability and opacity. We show that diagnosability is NL-complete for finite state systems, PSPACE-complete for safe convergent Petri nets (even with fairness), and EXPSPACE-complete for general Petri nets without fairness, while non diagnosability is inter-reducible with reachability when fault events are not weakly fair. Opacity is ESPACE-complete for safe Petri nets (even with fairness) and undecidable for general Petri nets already without fairness.
EN
Hybrid automata are a well-established modelling approach. The formalism is used in many real-time and control systems engineering projects, which makes model composition an increasingly relevant topic. A well-defined composition support allows concurrent engineering activities and the validation of larger systems. However, many existing publications seldom consider it or make unrealistic assumptions on the model design. The article discusses the common problems with hybrid automata composition and presents a new formalism, called linear time-invariant hybrid automata (LTI-HA), which targets specifically these issues. Our approach considers the superposition principle for flow functions, which makes it specifically useful for practical modelling purposes in the spacecraft and control domain. We compare the approach to well-known related ideas, such as hybrid I/O automata. Several properties of composition, such as commutativity, are proven.
EN
The article presents a zero-dimensional mathematical model of a tubular fuel cell and its verification on four experiments. Despite the fact that fuel cells are still rarely used in commercial applications, their use has become increasingly more common. Computational Flow Mechanics codes allow to predict basic parameters of a cell such as current, voltage, combustion composition, exhaust temperature, etc. Precise models are particularly important for a complex energy system, where fuel cells cooperate with gas, gas-steam cycles or ORCs and their thermodynamic parameters affect those systems. The proposed model employs extended Nernst equation to determine the fuel cell voltage and steadystate shifting reaction equilibrium to calculate the exhaust composition. Additionally, the reaction of methane reforming and the electrochemical reaction of hydrogen and oxygen have been implemented into the model. The numerical simulation results were compared with available experiment results and the differences, with the exception of the Tomlin experiment, are below 5%. It has been proven that the increase in current density lowers the electrical efficiency of SOFCs, hence fuel cells typically work at low current density, with a corresponding efficiency of 45–50% and with a low emission level (zero emissions in case of hydrogen combustion).
17
Content available Towards optimal design of energy efficient buildings
EN
Buildings consume half of all energy use and are also responsible for a similar proportion of carbon dioxide emission. The heat transfer across the building envelope - the shell of a house that separates the inside and outside - should generally be minimized. In the paper validation and verification based on Building Energy Simulation Test (BESTEST) of Energy3D computer code is presented. Next, computations performed by means of Energy 3D and Energy Plus for BESTEST building are compared. In the last part of the paper results for computations for real building are presented. Program Energy 3D proved to be an excellent tool for qualitative and quantitative analysis of buildings with respect to energy consumption.
PL
W związku ze znaczącym udziałem budynków w globalnym zapotrzebowaniu na energię ich projektowanie staje się coraz bardziej ukierunkowane na efektywne wykorzystanie nieodnawialnych zasobów takich jak np. paliwa kopalne. Celem niniejszej publikacji jest prezentacja możliwości jakie daje wykorzystanie oprogramowania do symulacji energetycznych budynków przy ich projektowaniu. We współpracy z firmą Wienerberger, która udostępniła dane dotyczące ich budynku modelowego oraz wyniki symulacji przeprowadzonych przez Narodową Agencję Poszanowania Energii S.A. w ramach optymalizacji jego projektu, autorzy porównali możliwości przykładowych, dostępnych komercyjnie narzędzi symulacyjnych – Energy3D oraz EnergyPlus (Design Builder) oraz porównali z wynikami benchmarkowymi na przykładzie budynku BESTEST. Poza omówieniem założeń obliczeniowych, a także dostępnych funkcjonalności programów, niniejszy artykuł zawiera streszczenie zagadnień wymagających rozwiązania przy symulacjach dynamicznej wymiany ciepła w budynkach oraz wybrane metody obliczeniowe stosowane w komercyjnych programach komputerowych.
PL
W artykule omówiono zasady wykonywania prób i pomiarów w instalacjach elektrycznych niskiego napięcia. Dokonano przeglądu postanowień najnowszej normy dotyczącej sprawdzania instalacji i zwrócono uwagę na zmiany przez nią wprowadzone.
EN
In the paper principles of testing of safety in low voltage systems, according to the standard PN-HD 60364-6:2016-07, are presented. The new provisions of the standard are compared with the provisions presented in the previous version: PNHD 60364-6:2008. Main changes in these provisions are underlined. It may be concluded that the new standard introduces only slight modifications to the verification process.
19
PL
Artykuł dotyczy prawnej kontroli metrologicznej przyrządów pomiarowych. Podaje cel i sposób sprawowania prawnej kontroli metrologicznej, a także wymienia akty prawne regulujące prawną kontrolę metrologiczną w Polsce.
EN
This article deals with legal metrological control of measuring instruments. Presents the purpose and the methods of performing legal metrological control, specifies acts of law regulating legal metrological control in Poland. It also describes proofs of metrological verification and shows markings used in Poland on protecting and verification seals. As an example is given legal metrological control related to active electrical energy meters. There are also mentioned upcoming changes in legal metrological control, including possibility of performing subsequent verification using statistical control.
EN
The purpose of the present study is to evaluate gains through measurement and verification methodology adapted from the International Performance Measurement and Verification Protocol, from case studies involving Energy Efficiency Projects in the Goias State, Brazil. This paper also presents the stochastic modelling for the generation of future scenarios of electricity saving resulted by these Energy Efficiency Projects. The model is developed by using the Geometric Brownian Motion Stochastic Process with Mean Reversion associated with the Monte Carlo simulation technique. Results show that the electricity saved from the replacement of electric showers by solar water heating systems in homes of low-income families has great potential to bring financial benefits to such families, and that the reduction in peak demand obtained from this Energy Efficiency Action is advantageous to the Brazilian electrical system. Results contemplate also the future scenarios of electricity saving and a sensitivity analysis in order to verify how values of some parameters influence on the results, once there is no historical data available for obtaining these values.
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