Large Scale Particle Image Velocimetry - merenje urbanog oticaja

Measuring velocities and discharge in the field is well established hydrologic discipline essential for observing and studying the hydrological processes. Small discharges formed on urban areas during rain events are usually low-depth surface flows very difficult to measure with standard devices and procedures. New method, Large Scale Particle Image Velocimetry (LSPIV), based on image processing, is introduced in hydrological practice in recent years as non invasive method for measuring surface velocity in free surface streams. In this article Large Scale Particle Image Velocimetry is applied in the field measurement of an urban discharge during a moderate storm event in Belgrade. .Terenska merenja brzina i protoka je široko rasprostranjena i poznata hidrološka disciplina neophodna za osmatranje i proučavanje hidroloških procesa. Mali oticaji koji se formiraju u urbanim područjima za vreme i nakon kišnih epizoda obično su sa malim dubinama što otežava njihovo određivanje tradicionalnim metodama i uređajima. Nova metoda, Large Scale Particle Image Velocimetry (LSPIV), bazirana na procesiranju slike, je uvedena u hidrološku praksu poslednjih godina kao neinvazivna metoda koja se upotrebljava kod određivanja polja površinskih brzina otvorenih tokova. U ovom radu LSPIV je primenjena na terenskom merenju urbanog oticaja u rigoli za vreme jedne umerene kišne epizode u Beogradu.

Large Scale Particle Image Velocimetry - merenje urbanog oticaja

Measuring velocities and discharge in the field is well established hydrologic discipline essential for observing and studying the hydrological processes. Small discharges formed on urban areas during rain events are usually low-depth surface flows very difficult to measure with standard devices and procedures. New method, Large Scale Particle Image Velocimetry (LSPIV), based on image processing, is introduced in hydrological practice in recent years as non invasive method for measuring surface velocity in free surface streams. In this article Large Scale Particle Image Velocimetry is applied in the field measurement of an urban discharge during a moderate storm event in Belgrade. .Terenska merenja brzina i protoka je široko rasprostranjena i poznata hidrološka disciplina neophodna za osmatranje i proučavanje hidroloških procesa. Mali oticaji koji se formiraju u urbanim područjima za vreme i nakon kišnih epizoda obično su sa malim dubinama što otežava njihovo određivanje tradicionalnim metodama i uređajima. Nova metoda, Large Scale Particle Image Velocimetry (LSPIV), bazirana na procesiranju slike, je uvedena u hidrološku praksu poslednjih godina kao neinvazivna metoda koja se upotrebljava kod određivanja polja površinskih brzina otvorenih tokova. U ovom radu LSPIV je primenjena na terenskom merenju urbanog oticaja u rigoli za vreme jedne umerene kišne epizode u Beogradu.

Kalibracija matematičkih modela vodovodnih sistema primenom genetskog algoritma

Model calibration is an important step in the modelling of water distribution systems. Since calibration is a process of adjusting model parameters so that model results fit best the measured data, it becomes a complex task if there are great many model parameters and respective measured data. This paper presents the calibration of the water distribution model for the city of Becej, based on the optimisation method called 'genetic algorithms (GA)'.Važan korak u procesu matematičkog modeliranja vodovodnih sistema je kalibracija modela. Kalibracija modela podrazumeva usklašivanje rezultata modela sa merenim vrednostima podešavanjem parametara modela. U slučaju velikog broja parametara, rezultata i merenih vrednosti može biti izuzetno složen poduhvat. U ovom radu je prikazana primena genetskih algoritama (GA), optimizacione metode bazirane na prirodnoj evoluciji, u procesu kalibracije vodovodne mreže grada Bečej

Kalibracija matematičkih modela vodovodnih sistema primenom genetskog algoritma

Model calibration is an important step in the modelling of water distribution systems. Since calibration is a process of adjusting model parameters so that model results fit best the measured data, it becomes a complex task if there are great many model parameters and respective measured data. This paper presents the calibration of the water distribution model for the city of Becej, based on the optimisation method called 'genetic algorithms (GA)'.Važan korak u procesu matematičkog modeliranja vodovodnih sistema je kalibracija modela. Kalibracija modela podrazumeva usklašivanje rezultata modela sa merenim vrednostima podešavanjem parametara modela. U slučaju velikog broja parametara, rezultata i merenih vrednosti može biti izuzetno složen poduhvat. U ovom radu je prikazana primena genetskih algoritama (GA), optimizacione metode bazirane na prirodnoj evoluciji, u procesu kalibracije vodovodne mreže grada Bečej

Merenje protoka na kratkim objektima u hidraulički neregularnim uslovima na primeru HE 'Đerdap 2'

Hydraulic conditions at short structures in most cases prevents the existence of cross sections with parallel streamlines and fully developed turbulent flow profile. In such conditions the flow measurement is rather challenging. In spite of recent developments in flow measuring methods, there is no universal device that can be used in inappropriate hydraulic conditions with adequate accuracy. This paper gives the overview of the contemporary flow measuring methods with the focus on its usability in hydraulically difficult conditions. As a case study, the problem of flow measurements at the intake of the aggregates of Hydroelectric Power Plant (HE) 'Djerdap 2' is presented. Due to its position in Danube and leftovers of preconstruction works in river bed, there is a significant incoming angle of the water to the HE 'Djerdap' turbines. The streamlines angle is larger at the Serbian side then at the Rumanian side, resulting the worse efficiency of the Serbian turbines. To analyze the effect of the curved incoming stream to the turbine performance, the true flowrate has to be measured. Since the Kaplan's short turbines were used and no regular cross section where flow can be measured using standard methods exists, available measuring methods for velocity field measurement were analyzed in this paper. For selected method based on electromagnetic velocity measurement devices, the field check was performed and presented. The paper concludes with the assessment of accuracy and total costs for selected flow measurement method.Merenje protoka na objektima gde ne postoje uslovi za formiranje pravolinijskog razvijenog turbulentnog strujanja predstavlja poseban izazov. I pored značajnog napretka u razvoju merne tehnike, ne postoji univerzalna metoda kojom je moguće izmeriti protok sa u napred poznatom tačnošću. U ovom radu je napravljen presek trenutno raspoloživih metoda sa osvrtom na njihovu upotrebljivost u složenim uslovima kao što je slučaj prostornog rasporeda brzina. Kao primer, razmatran je problem merenja protoka na zahvatima agregata hidroelektrane HE 'Đerdap 2'. Zbog asimetričnog položaja elektrane u odnosu na maticu toka reke Dunava, kao i zbog toga što radovi na čišćenju dna uzvodno od brane nisu sprovedeni do kraja, voda na turbine dotiče pod izvesnim uglom. Taj ugao je veći kod turbina bližih sredini brane (kod srpskih turbina) dok je kod turbina postavljenih uz levu obalu (rumunsku) zanemarljiv. Da bi se analizirao uticaj kosog dostrujavanja na rad turbina, neophodno je izmeriti protoke. Kako su kod primenjenih kratkih cevnih agregata loši hidraulički uslovi za kvalitetno merenje protoka standardnim metodama, u radu se analiziraju moguće varijante snimanja prostornog rasporeda brzina. Za slučaj korišćenja elektormagnetnih sondi, obavljena je i provera uticaj a smetnji od strane magnetnog polja generatora. Na kraju, procenjena je moguća tačnost merenja protoka kao i cena takvog sistema

Validacija podataka hidrotehničkih procesa

The knowledge about hydraulic and hydrologic processes is based on the monitoring of environmental and technical systems where they take place. The result of monitoring are the data that can be transformed into some useful information and knowledge, but only if the level of data reliability and accuracy is known. A framework for data validation and check according some additional knowledge about observed processes is presented in this paper. The validation system is designed in a way that can be adjusted to different levels of data validation based on time when the validated data is needed (automatic, semi-automatic and manual) and on availability of additional data that can be used in validation process (technical characteristics of the monitoring system, experts knowledge about monitored process or existing relations between monitored variables). As a result of data validation, every data value is labeled with validation grade that shows how much the data value is representative for monitored hydraulic and hydrologic process.Spoznaja o hidrotehničkim procesima potiče od osmatranja prirodnih i tehničkih sistema u kojima se odvijaju. Proizvod osmatranja su podaci koje je dalje moguće pretvoriti u korisne informacije i znanje, ali samo ako se zna koliko su ti podaci pouzdani i tačni. Cilj ovog rada je da predloži sistem po kome bi se mogla sprovesti validacija i provera prikupljenih podataka na osnovu prethodnog znanja o osmatranom hidrotehničkom procesu. Sistem je osmišljen tako da se može prilagoditi različitim nivoima validacije u pogledu vremena kada su potrebni validovani podaci (automatska, poluautomatska ili ručna validacija) kao i u pogledu raspoloživosti hidrotehničkih simulacionih modela i dodatnih informacija (tehničkih karakteristika sistema za osmatranje, ekspertskog znanja o osmatranom procesu ili relacije između merenih veličina). Rezultat validacije je ocena koliko je svaki podatak reprezentativan za osmatrani hidrotehnički proces

Propagacija neodređenosti kod linijskih modela otvorenih tokova

Free surface flow is usually simulated by 1D numerical models. This approach assumes flow simplification and requires model calibration in order to reproduce flow characteristics in a realistic way. The calibration and input data are to some extent inherently erroneous. To check the influence of data errors on the model results, it is necessary to perform some additional analysis. This paper deals with the impact of input data uncertainty on model results, considering only compiled models (those that cannot be conceptually changed, or modified on the source code level). Three forms of data uncertainty representation are presented: intervals, fuzzy sets and statistical distribution.Tečenje u otvorenim tokovima se često modelira linijskim (1D) modelom. Takav pristup problematici podrazumeva da se složena strujna slika kod tečenja u otvorenim tokovima pojednostavljuje, a kalibracijom parametara modela se postiže da model verno simulira prirodni proces. I u fazi kalibracije, kao i kasnije u fazi korišćenja modela, moguće je da raspoloživi podaci o fenomenu u sebi nose određenu grešku. Da bi se proverio uticaj greške na rezultate proračuna, neophodno je sprovesti dodatne analize. U radu se prikazuje analiza neodređenosti rezultata usled neodređenih ulaznih vrednosti i parametara modela. U ovom radu se razmatraju zatvoreni numerički modeli (kojima se ne može menjati koncept ni programski kod) i na način kako se predstavljaju neodređene veličine (u obliku intervala, rasplinutog skupa i statističke raspodele)

Validacija podataka hidrotehničkih procesa

The knowledge about hydraulic and hydrologic processes is based on the monitoring of environmental and technical systems where they take place. The result of monitoring are the data that can be transformed into some useful information and knowledge, but only if the level of data reliability and accuracy is known. A framework for data validation and check according some additional knowledge about observed processes is presented in this paper. The validation system is designed in a way that can be adjusted to different levels of data validation based on time when the validated data is needed (automatic, semi-automatic and manual) and on availability of additional data that can be used in validation process (technical characteristics of the monitoring system, experts knowledge about monitored process or existing relations between monitored variables). As a result of data validation, every data value is labeled with validation grade that shows how much the data value is representative for monitored hydraulic and hydrologic process.Spoznaja o hidrotehničkim procesima potiče od osmatranja prirodnih i tehničkih sistema u kojima se odvijaju. Proizvod osmatranja su podaci koje je dalje moguće pretvoriti u korisne informacije i znanje, ali samo ako se zna koliko su ti podaci pouzdani i tačni. Cilj ovog rada je da predloži sistem po kome bi se mogla sprovesti validacija i provera prikupljenih podataka na osnovu prethodnog znanja o osmatranom hidrotehničkom procesu. Sistem je osmišljen tako da se može prilagoditi različitim nivoima validacije u pogledu vremena kada su potrebni validovani podaci (automatska, poluautomatska ili ručna validacija) kao i u pogledu raspoloživosti hidrotehničkih simulacionih modela i dodatnih informacija (tehničkih karakteristika sistema za osmatranje, ekspertskog znanja o osmatranom procesu ili relacije između merenih veličina). Rezultat validacije je ocena koliko je svaki podatak reprezentativan za osmatrani hidrotehnički proces

Improved real-time data anomaly detection using context classification

The number of automated measuring and reporting systems used in water distribution and sewer systems is dramatically increasing and, as a consequence, so is the volume of data acquired. Since real-time data is likely to contain a certain amount of anomalous values and data acquisition equipment is not perfect, it is essential to equip the SCADA (Supervisory Control and Data Acquisition) system with automatic procedures that can detect the related problems and assist the user in monitoring and managing the incoming data. A number of different anomaly detection techniques and methods exist and can be used with varying success. To improve the performance, these methods must be fine tuned according to crucial aspects of the process monitored and the contexts in which the data are classified. The aim of this paper is to explore if the data context classification and pre-processing techniques can be used to improve the anomaly detection methods, especially in fully automated systems. The methodology developed is tested on sets of real-life data, using different standard and experimental anomaly detection procedures including statistical, model-based and data-mining approaches. The results obtained clearly demonstrate the effectiveness of the suggested anomaly detection methodology