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1352. Design of a new hybrid artificial neural network method based on decision trees for calculating the Froude number in rigid rectangular channels

Creator:
Ebtehaj, Isa, Bonakdari, Hossein, Zaji, Amir Hossein, Bong, Charles Hin Joo, and Ghani, Aminuddin Ab
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
decision tree, incipient motion, Multilayer perceptron (MLP), and Froude number
Language:
Slovak
Description:
A vital topic regarding the optimum and economical design of rigid boundary open channels such as sewers and drainage systems is determining the movement of sediment particles. In this study, the incipient motion of sediment is estimated using three datasets from literature, including a wide range of hydraulic parameters. Because existing equations do not consider the effect of sediment bed thickness on incipient motion estimation, this parameter is applied in this study along with the multilayer perceptron (MLP), a hybrid method based on decision trees (DT) (MLP-DT), to estimate incipient motion. According to a comparison with the observed experimental outcome, the proposed method performs well (MARE = 0.048, RMSE = 0.134, SI = 0.06, BIAS = -0.036). The performance of MLP and MLP-DT is compared with that of existing regression-based equations, and significantly higher performance over existing models is observed. Finally, an explicit expression for practical engineering is also provided.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1353. Detection of changes in flow regime of rivers in Poland

Creator:
Wrzesiński, Dariusz and Sobkowiak, Leszek
Type:
article, model:article, and TEXT
Subject:
flow regime, detection of changes, empirical distribution function, typological classification, and Ward’s hierarchical clustering method
Language:
Slovak
Description:
The aim of this study is to detect changes in flow regime of rivers in Poland. On the basis of daily discharges recorded in 1951–2010 at 159 gauging stations located on 94 rivers regularities in the variability of the river flow characteristics in the multi-year period and in the annual cycle were identified and also their spatial uniformity was examined. In order to identify changes in the characteristics of river regime, similarities of empirical distribution functions of the 5-day sets (pentads) of discharges were analyzed and the percent shares of similar and dissimilar distributions of the 5-day discharge frequencies in the successive 20-year sub-periods were compared with the average values of discharges recorded in 1951–2010. Three alternative methods of river classification were employed and in the classification procedure use was made of the Ward’s hierarchical clustering method. This resulted in identification of groups of rivers different in terms of the degree of transformation of their hydrological regimes in the multi-year and annual patterns.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1354. Determinants of change in the duration of ice phenomena on the Vistula River in Toruń

Creator:
Pawłowski, Bogusław
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
ice phenomena, Vistula River, natural factor, and human impact
Language:
Slovak
Description:
Winter season temperatures are becoming warmer. However, the transformation of the ice regime on the Vistula River in Toruń has also been affected by river engineering. In particular, the construction and operation of the Włocławek Dam had a significant impact on ice processes. The article presents the results of an analysis determining the contribution of natural and anthropogenic factors to the duration of ice phenomena and ice cover on the Vistula River in the city of Toruń. Compared to the end of the nineteenth century, there has been a reduction in the duration of ice phenomena from 88 to 53 days and of ice cover from 40 to 7 days (in the period of 1882-2011). The article compares the duration of ice cover and winter temperature in three different periods: before the completion of river engineering works (1882-1907); for the controlled river (1908-1969), and for the controlled river with the Włocławek Dam upstream of Toruń (1970-2011). The results showed a significant role of these anthropogenic factors in the changes of the ice cover duration on the Vistula River in Toruń.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1355. Determination of different types of sediments in a river reservoir and computation of their volumes

Creator:
Rudiš, Miroslav, Hájek, Radvan, and Hrubec, Karel
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
river reservoir, different type of sediments, radar, volumes of polluted and non-polluted sediments, říční nádrž, různé typy sedimentů, and objemy znečištěných a neznečistěných sedimentů
Language:
Slovak
Description:
Paper deals with sediments settled in the Elbe reservoir Les Království (King´s Forest) between 1914 and 2005. This reservoir is laid on upper Elbe closing the mountain watershed of Krkonoše (Giant Mountains) with the source of the river. To this profile, watershed can be taken as mountain and foothill area. The sediments, before approximately 1950, were non-polluted by heavy metals and specific organic matter because of the undisturbed natural environment. After that time, the conditions of sedimentation became worse. With the industrial boom and ploughing of the grazing land away there, the amount of sediments settled in the reservoir increased much times and high pollution appeared. To this point, the badly treated sewage waters and washing outs of the soil with pesticides and herbicides from the new high-sloped cropland contributed for many years. With this, the amount of sediments increased up to 21 % of the total volume of the reservoir, i.e., approximately, to 2 mil. m3 . It was decided in 1984 that the sediments have to be removed from reservoir. Up to this time, the quality of sediments was followed in the surface layers only and this quality was applied to all layers of sediments. Thus the wrong idea appeared that all sediments are polluted. On the contrary, the authors suppose that the old layers are not polluted and, in the case of cleaning of the reservoir, these need not be stored in a protected dump. Differentiating the sediments to polluted and non-polluted would bring a considerable increase in economy of cleaning. Thus the authors looked for a method to distinguish the sediment components one another. Among others, the method of the radar search of sediments appeared to be promising enough to describe the sediment layers from the actual bottom down to the original bedrock. To this aim, a new radar antenna working in two regimes was applied. In shallow parts of the reservoir, it was towed in cross profiles on water surface while in the deep ones it was moved along the bottom escorted by a diver. Using this, we were able to distinguish 5 components of sediment (i.e. the non-consolidated and cohesive sediment, the sandy loam, sandy silt and the gravel), to fix their positions and to estimate, in accordance to their apparent grain distribution, if they could be polluted or not. Moreover the mathematical method just presented here was worked out to compute volumes of different sediment components directly from radar signals. This method enables to compute the sediment volumes in relatively straight parts of the valley and the meandering ones., Thus the authors have presented a method enabling the estimate of component volumes on one side and to fix their positions to take samples for quality analyses on the other side., and Příspěvek se zabývá sedimenty usazenými v labské nádrži Les Království v období od r. 1914 do současnosti. Nádrž byla vybudovaná na horním Labi a prakticky uzavírá horskou a podhorskou část povodí, v němž je i pramen Labe. Sedimenty usazené v nádrži řekněme do r. 1950 nevykazují znečistění ani těžkými kovy, ani specifickými organickými látkami. Potom se však podmínky sedimentace zhoršily. S tehdejší extensivní industrializací a rozšířením rostlinné výroby i na svažité pozemky dřívějších luk a pastvin došlo k masivnímu zvýšení množství sedimentů přinesených do nádrže a podstatně se zhoršila jejich kvalita díky špatně čištěným odpadním vodám a intenzivnímu užívání chemie s pesticidy a herbicidy na nových velmi svažitých polích. Do r. 1984 stoupl pak objem sedimentů na cca 21 % objemu nádrže, tj. na téměř 2 mil. m3 . Až donedávna se uskutečňovaly kvalitativní analýzy pouze v povrchových vrstvách sedimentů a tak vznikl chybný názor, že celý objem sedimentů je silně znečistěný. Naproti tomu autoři předpokládají, že sedimenty usazené před r. 1950 nejsou znečistěné a nemusí být uloženy na zajištěné skládky. Rozlišení sedimentů na znečištěné a neznečištěné povede k velkým úsporám při čistění nádrže. K tomu cíli autoři hledali vhodnou metodu. Byla zvolena geofyzikální metoda radarového průzkumu dna, která může rozlišit jednotlivé složky sedimentů od jejich současné úrovně až po skalní podklad. K tomu byla použita radarová anténa pracující ve dvou režimech, a to tažením po hladině v malých hloubkách nádrže a tažením po dně za doprovodu potápěče ve větších hloubkách. Touto metodou jsme rozlišili 5 složek sedimentů (tj. nezpevněný sediment, kohesivní sediment, písčité hlíny, písčité bahno a štěrk), zjistili polohu vrstev a následně podle jejich granulometrie mohli odhadnout, jestli mohou obsahovat význačné znečištění. Tyto výsledky byly porovnány se všemi dosažitelnými kvalitativními analýzami a s jejich využitím jsme mohli rozlišit, které vrstvy je při čistění nádrže nutno uložit na zajištěnou skládku a které je možno využít jako výplňový materiál při zemních pracích. Tímto rozlišením je možno ušetřit značné náklady při čistění nádrže.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1356. Determination of hydraulic conductivity of a suspension

Creator:
Petrova, Marketa and Mls, Jiri
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
hydraulic conductivity, kaolin, suspension, and gravity thickening
Language:
Slovak
Description:
The process of sedimentation and subsequent gravity compression of kaolin and water suspensions was investigated experimentally. 45 batch tests were carried out and the time dependence of the height of the suspension column was measured. The one-dimensional equations of Darcian mechanics of two-phase porous media are applied to formulate the studied process mathematically. A very natural assumption makes it possible to find a solution of the forward problem for a starting period of the process. Analysis of the theoretical function and the experimental data gives hydraulic conductivity as a function of the suspension concentration. The obtained results are presented and discussed.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1357. Determination of potential damage to representatives of real estate property in areas afflicted by flooding

Creator:
Korytárová, Jana, Šlezingr, Miloslav, and Uhmannová, Hana
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
construction work, flood, water level, water management, value of assets in the area, flooding damage, anti-flooding measures, efficiency of investment in construction, stavební objekt, povodeň, hladina vody, vodní hospodářství, hodnota majetku v území, povodňová škoda, protipovodňová opatření, and efektivnost stavebních investic
Language:
Slovak
Description:
The article is aimed at identifying the basic approaches for assessing the economic efficiency of public projects and their application whilst assessing the efficiency of preventive anti-flooding measures. One of the important things when deciding about applying these measures is information on what value of real estate assets these measures protect and what level of potential damages they are able to prevent. Within the research assignment, therefore, the issue of property indicators in the area is dealt with, based on which the value of real estate assets in the area can be determined, and subsequently the amount of damage can be specified for when the area is hit by potential natural disasters (flood) by using damage curves processed for individual representatives of real estate property. This problem is solved in the ''Procedures for supporting decision-making in the field of securing the stability of the area in terms of possible flooding'' grant project No. 103/05/0016 with support of the Czech Science Foundation. More information about this methodology is on www.fce.vutbr.cz/ekr, the final report of this project will carried in February 2008 also on http://pala.gacr.cas.cz/. and Článek je zaměřen na identifikaci základních přístupů pro hodnocení ekonomické efektivnosti veřejných projektů a jejich uplatnění při posuzování efektivnosti preventivních protipovodňových opatření. Pro rozhodování o uskutečnění těchto opatření je mimo jiné důležitá informace, jakou hodnotu nemovitého majetku tato opatření chrání, případně jak vysokým škodám jsou schopna zabránit. V rámci výzkumného projektu je proto řešena problematika územních majetkových ukazatelů, na základě kterých lze stanovit hodnotu nemovitého majetku v území a následně při zasažení území potenciální živelní pohromou - povodní s využitím křivek poškození zpracovaných pro jednotlivé reprezentanty nemovitého majetku vyčíslit výši škody. Tato problematika je řešena v grantovém projektu č. 103/05/0016 s názvem ''Postupy pro podporu a rozhodování v oblasti stavebních investic při zajištění stability území z pohledu možného zaplavení'' za podpory Grantové agentury České republiky. Více informací o vyvinuté metodice lze nalézt na www.fce.vutbr.cz/ekr; závěrečná zpráva projektu bude uveřejněna také na http://pala.gacr.cas.cz/.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1359. Detský element v zrkadle archeologických prameňov včasného stredoveku /

Creator:
Molnárová, Martina
Type:
text and studie
Subject:
Archeologie, středověk raný, dětství, hroby, ritus pohřební, archeologie, nálezy, Slovensko od příchodu Slovanů do r. 1301, ženská otázka, rodina, děti, životní úroveň, and archeologické výzkumy, archeologie v muzeích a archivech
Language:
Slovak
Description:
Das Element des Kindes im Spiegel der archäologischen Quellen des frühen Mittelalters.
Rights:
unknown

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