U radu su provedene numeričke simulacije hidrauličkih tranzijenata u sustavu crpne hidroelektrane (CHE) Fužine pomoću nestacionarnog 1D modela strujanja pod tlakom u cijevi. Primjenom nekonzervativne ...formulacije modela nestacionarnog strujanja tekućine u cijevi pod tlakom i fluks-limitirane numeričke metode drugog reda postignuta je zadovoljavajuća točnost modela. Dobiveni numerički rezultati su pokazali dobro slaganje s izmjerenim podacima promatranog sustava.
Cilj je rada utvrditi doprinosi li opažanje promjena u prirodi i kritičko promišljanje uz simulacije promjena na Zemlji tijekom vremena, razumijevanju koncepta globalnih klimatskih promjena u nastavi ...Prirode. Istraživanje je provedeno 2022. godine na uzorku 76 učenika 6. razreda. Temeljem materijala za poučavanje i samostalno učenje na BUBO platformi, učenike se vodilo kroz terensko istraživanje i prikupljanje podataka od starijih sugrađana o opaženim promjenama u njihovu okolišu unazad nekoliko desetljeća te učenje uz simulacije procesa koji dovode do promjena. Provjerom predkoncepcija, uočena je miskoncepcija o učinku staklenika kao izrazito lošoj pojavi i mišljenje da su klimatske promjene isključivo posljedica antropogenog utjecaja. Pristup poučavanju o klimatskim promjenama temeljio se na uspoređivanju pozitivnih i negativnih posljedica učinka staklenika za opstanak života na Zemlji te kako razlučiti ljudski utjecaj na klimu i prirodne procese koji mogu doprinijeti promjeni klime. Rezultati završne pisane provjere ukazuju napredak u razumijevanju pojava i procesa vezanih uz globalno zatopljenje i klimatske promjene, uz ispravljanje miskoncepcija i bolje povezivanje opaženih promjena na lokalnoj razini s procesima koji se odvijaju na globalnoj razini. Učenjem su osviješteni načini kojima svaki učenik, a time i svaki pojedinac, može doprinijeti usporavanju globalnih klimatskih promjena.
U radu je demonstrirana primena metode automatizovanog ponavljanja nezavisnih simulacionih eksperimenata sa prikupljanjem statistike slučajnih procesa, u dostizanju i kontroli tačnosti simulacionih ...rezultata u simulaciji sistema masovnog opsluživanja Monte Karlo. Metoda se zasniva na primeni osnovnih stavova i teorema matematičke statistike i teorije verovatnoće. Tačnost simulacionih rezultata dovedena je u direktnu vezu sa brojem ponavljanja simulacionih eksperimenata. / The paper presents an application of the Automated Independent Replication with Gathering Statistics of the Stochastic Processes Method in achieving and controlling the accuracy of simulation results in the Monte Carlo queuing simulations. The method is based on the application of the basic theorems of the theory of probability and mathematical statistics. The accuracy of the simulation results is linked with a number of independent replications of simulation experiments.
U radu je opisana osnovna ideja metode pod nazivom 'Automatizovano ponavljanje nezavisnih simulacionih eksperimenata sa prikupljanjem statistike slučajnih procesa'. Data je matematička osnova metode ...i prikazane su preporuke za implementaciju metode u formu algoritma za računarski program. Pregledno su istaknuta potrebna ekspertska znanja za uspešan razvoj konceptualnih i simulacionih modela. Metoda je testirana u istraživanju sistema masovnog opsluživanja. / This paper presents a basic idea of the method entitled 'Automated Independent Replications with Gathering Statistics of Stochastic Processes'. The mathematical foundation of the method is offered, as well as some recommendations for practical implementation of the met hod in the form of a computer program algorithm. A set of different expert knowledge needed for a successful development of conceptual and simulation models is pointed out in a separate review. The method has been tested in the modeling and simulation of queuing systems. Multidisciplinary character of simulation modeling This paper presents a basic idea of the method entitled 'Automated Independent Replications with Gathering Statistics of Stochastic Processes'. A clear review of expert knowledge needed for successful development of a conceptual model as well as a simulation one is offered. Simulation modeling of systems and processes in any military branch assumes a multidisciplinary approach. This is not a consequence of a free choice, but of needs and problems which arise in a research process and which require synchronized use of knowledge from different areas and scientific disciplines. In studies of queuing systems, these disciplines are: queuing theory, probability theory, mathematical statistics, stochastic processes, mathematical analyses, Monte Carlo simulation modeling, computer programming, knowledge about a real system under study, etc. Specific features of real queuing systems Consistency, fidelity or agreement of the model with the real system under study is one of the most important characteristics of the model. This means that a conceptual model should present reality as it really is. In the context of queuing system modeling, this means the following: if a real system works for some finite time, then the same should be applied for a model as well; if there can be any traffic intensity including overloading, then a model should be conceived accordingly, etc. Mathematical basis of the AIRGSSP method The mathematical basis of the method is offered, as well as some recommendations for practical implementation of the method in a form of a computer program algorithm. Explicitly, the mathematical foundations of the AIRGSSP method are three statements; the first one, the Bernoulli law of large numbers, or the first limit theorem: the frequency of one random event in a many times repeated experiment tends to the probability of that event; the second one, the perception of the behavior of a queuing system as a kind of a stochastic process, and the support for the statistics of stochastic processes; and the third one, the use of an interval estimation of proportion for establishing the control of the simulation result accuracy. Description of the implementation of the AIRGSSP method The application of the AIRGSSP method includes the following: development of a conceptual model; definition of performance measures; development of the basic structure of the simulation model; implementation of a module for the stochastic process statistics; implementation of a module for automatization of independent replications of the simulation experiment; calculation of a number of replications of the simulation experiment; and translation of the model into the computer code. Conclusion A detailed description for the practical implementation of the method 'Automated Independent Replications with Gathering Statistics of Stochastic Processes' is given. The capacity and advantages of the AIRGSSP method are particularly clear in the cases of modeling and simulation of: heavy-loaded and overloaded systems, complex systems with a large number of possible system states as well as systems engaged for some finite time. These are exactly the systems and working conditions where other methods usually fail.
In Serbia there existed a period of investment growth, which reflected itself on the growth of stock market indices. The aim of this paper is to evaluate market risk at the Serbian market in period ...of investment growth, applying the method of historical simulation to a portfolio consisting of shares that are continuously traded at the Belgrade Stock Exchange, for which the data existed, since the Serbian stock exchange market is a young one, practically beginning. Method verification was carried out at different confidence levels, which demonstrated that the method underestimated the risk for the confidence level of 99%.
Erodirana tla karakteriziraju degradirana fizička, kemijska i biološka svojstva koja smanjuju produktivnost tla i predstavljaju veliku prijetnju okolišnoj sigurnosti i stabilnosti ekosistema. Cilj ...ovog rada je istražiti utjecaje upravljanja tlom na svojstva tla te eroziju tla u vinogradu, uspoređujući obrađeni (TV) i trajno zatravljeni vinograd (GCV). Istraživani vinograd nalazi se u Sisačko-Moslavačkoj županiji, Hrvatska (45°31’ S, 16°43’ I). Terenski rad sastojao se od 8 kišnih simulacija, uzorkovanja tla te prikupljanja erozijskog otjecanja. Rezultati ukazuju da su TV parcele imale niže (P<0.05) udjele organske tvari (SOM) (2.80%), srednje veličine strukturnih agregata (MWD) (2.56 mm) i udjele vodo-stabilnih strukturnih agregata (WSA) (53.1%) od GCV parcela. Vrijeme do površinskog stagniranja vode (PT) i vrijeme do početka otjecanja
(RT) bili su niži u TV što je uzrokovalo duže vrijeme otjecanja i povećalo otjecanje vode (WR) te gubitak sedimenata (SL). Na TV je zabilježeno 745.4 puta veći SL nego na GCV (TV 6.87 t/ha naspram 0.0092 t/ha). Viši SL uzrokovao je veće gubitke hraniva u TV. Obrada tla je prepoznata kao neodrživa praksa u području istraživanja te je ključni faktor povećane erodibilnosti tla kao i potencijalnih okolišnih opasnosti uzrokovanih visokim gubitkom sedimenata.
U središtu je interesa ovog rada ponašanje spojeva prirubnice i mekane gumene brtve koja je tipična vrsta brtve za isparivače. Montirana konstrukcija ispitala se prema normi EN 13445-3, a naprezanja ...su se mjerila tenzometrima. Numerička analiza u programskom paketu ABAQUS obuhvaćala je nekoliko modela s različitim detaljima. Ti su modeli bili podešeni u skladu sa zabilježenim podacima iz ispitivanja. U radu su prikazane i dokumentirane preporuke koje se tiču složenosti modela koji je potreban kako bi se postigla zadovoljavajuća razina predviđanja nelinearnog ponašanja spojeva prirubnica.
Digitalna i njoj pripadajuća tehnološka evolucija posljednjih godina pretvorila se u riječi kao Virtualna stvarnost i umjetna inteligencija. Šira upotreba ovih, ali i drugih tehnologija u arhitekturi ...dosta je ograničena zbog nedostatka IT alata s kojima su se arhitekti susretali s obzirom na to da su bili dostupni jedino u posljednjih nekoliko godina. Evolucija alata koju koriste arhitekti može biti komprimirana i pojednostavljena promatrajući je u tri faze: crtaća ploča, CAD sustavi, game enginei. Okviri ovih faza predstavnici su povijesnog konteksta u kojem su se koristili ili se još uvijek koriste. Ovo proučavanje koje se temelji na diplomskom radu nedavno obrađenom na Politecnico di Milano 14, ispituje ulogu koju game enginei mogu igrati u grafičkoj prezentaciji i procesu projektiranja. Konkretnije, bliže sagledava Unreal Engine kao alat za stvaranje okoline projektiranja u stvarnom vremenu i koristeći tehnologije Umjetne inteligencije predstavlja korisničko razmišljanje u prostoru kao korisnu podršku i važan dio strategija projektiranja s ciljem implementacije i evaluacije projektantskih opcija. Za ovu svrhu, brojne simulacije su izvedene uzimajući u obzir i protoke korisnika temeljene na konkretnom prostoru, ali i generiranje prostora temeljeno na protocima korisnika.
The key characteristics of entrepreneurs of the twenty-first century include the willingness to take responsibility, ability to develop strategic visions and objectives, and powerful motivation to ...succeed. The challenges of the entrepreneurial environment are mirrored in the higher education system that has the task of preparing students for the unpredictable and turbulent labour market. Business decisions are vital for the survival of an enterprise, together with the entrepreneurial functions of project planning, development and execution, as well as the ability to adapt to teamwork settings, be proactive and take risks. Accordingly, keeping abreast of innovative and interactive trends in teaching is a crucial element in the overall development of the skills and competencies of future entrepreneurs, in particular, and the teaching process, in general.
The purpose of this paper is to investigate the satisfaction of students with regard to the benefits derived from the application of active teaching methods in an undergraduate university study programme at the Faculty of Tourism and Hospitality Management of the University of Rijeka. Using business simulations in teaching the course “Entrepreneurial Management and Innovation” is an active learning method that allows students to experiment with business strategies, in a risk-free setting, in the strategic areas of managing human resources, capacities, investments, service quality, prices and marketing.
Research for the purposes of this paper was conducted among second-year, full-time students of the undergraduate university study programme, using the survey method and a pre-designed structured questionnaire. Research results point to a high level of student satisfaction with regard to the innovative approach to teaching and the benefits of active learning methods used, which the respondents distinctly prefer relative to traditional seminar-based teaching. The study indicates a high level of satisfaction with the benefits of simulations in the process of developing entrepreneurial spirit and managerial skills but also a lower level of satisfaction in the segment of complexity in connection with previously acquired knowledge.
The results of this study can contribute to improving the existing knowledge and to expanding the use of active learning through the application of a hybrid learning model that opens up opportunities for achieving the ultimate goal of enhancing the employability of students and increasing their competitiveness.
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