Several alternative definitions of extreme events are proposed. As the first step a statistical analysis of daily precipitation measurement time series from the Hurbanovo SHMI Observatory and elaboration of potentially dangerous precipitation events is carried out. Then, combined characteristics based on daily temperature, daily air humidity and daily precipitation totals are computed. The drought index based on normalized deviations from long-term averages is defined. Alternatively, to define extreme events ''Data envelopment analysis'' (DEA) is employed with K-day periods of values of temperature, humidity and precipitation corresponding to decision making units. In this paper we have used the period of K = 10 days for both methodologies for identification of extreme events. The results of all definitions of extreme events are compared. and V článku navrhujeme niekoľko definícií extrémnych udalostí. Ako prvý krok je vypracovaná štatistická analýza denných úhrnov zrážok z observatória SHMÚ v Hurbanove, na základe ktorej označujeme extrémne udalosti. Následne počítame kombinované charakteristiky období sucha založené na denných údajoch teploty, vlhkosti vzduchu a denných úhrnoch zrážok. Index sucha je založený na normalizovaných odchýlkach od dlhodobých priemerov. Alternatívne definujeme extrémne udalosti na základe DEA analýzy, kde K-denné periódy teploty, vlhkosti a zrážok slúžia ako rozhodovacie jednotky. V tomto článku sme na identifikáciu extrémnych udalostí pre obe metodológie použili periódu K = 10 dní. Výsledky všetkých prístupov nakoniec porovnávame.
In the Southeastern Black Sea Region, rivers are dammed for hydroelectric power and irrigation. The natural course of fluvial alluvium transport is almost completely altered because of planned and constructed dams and coastal protection measures. Decreasing volume of sediment carried to the sea cause intensification of the shore erosion. The Black Sea Rivers and coastal areas of Turkey and Georgia are under heavy anthropogenic pressure because of the bed material extraction and coastal erosion rate. In this study, environmental effects of dams and related effects of sediment transport on coastal erosion in the Eastern Black Sea region are discussed. and Rieky v juhovýchodnej časti regiónu Čierneho mora sú prehradené priehradami, ktoré slúžia na výrobu elektrickej energie a na závlahy. Prirodzený transport plavenín a splavenín sa v dôsledku výstavby plánovaných a realizovaných priehrad takmer úplne zmenil. Znížený objem sedimentov dopravovaných do mora spôsobuje intenzifikáciu erózie brehov riek. Rieky ústiace do Čierneho mora v oblasti pobrežia Turecka a Gruzínska sú výrazne ovplyvnené ľudskou činnosťou, ako je ťažba materiálu z riek a eróziou brehov. V tejto práci sa analyzuje vplyv priehrad na životné prostredie krajiny vo východnej časti Čierneho mora.
In the paper, I discuss Robert Kirk’s attempt to refute the zombie argument against materialism by demonstrating, “in a way that is intuitively appealing as well as cogent”, that the idea of phenomenal zombies involves incoherence. Kirk’s argues that if one admits that a world of zombies z is conceivable, one should also admit the conceivability of a certain transformation from such a world to a world z* that satisfies a description D, and it is arguable that D is incoherent. From which, Kirk suggests, it follows that the idea of zombies is incoherent. I argue that Kirk’s argument has several minor deficiencies and two major flaws. First, he takes for granted that cognitive mental states are physical (cognitive physicalism), although a zombist is free to—and would better—reject this view. Second, he confuses elements of different scenarios of transformation, none of which results in the incoherent description D.
This study deals with uncertainty, stability and robustness in reservoirs operation. These properties of control currently represent a new aspect in the utilization of water resources and their systems in changing conditions. The study is based on the modern control theory of dynamic systems. It also explains the aims and exacting nature of methodical approaches. Instead of analytical methods, simulation models were used for the solution of runoff stability during different flood situations. The flood protection effect of the reservoir was solved on the basis of a set of generated synthetic flood waves. Then, the stability of the runoff was investigated in different hydrological situations. The study concludes that the stability of the runoff from the reservoir is possible to reach only within certain limits, while in a catastrophic flood situation, it is unrealistic. It also concludes that the combination of different flood protection measures is purposeful, e.g. a larger flood-control storage, predischarge, intensification of the hydrometeorological forecast, stream-channel regulation, etc. Finally, the study suggests themes for further investigation in this field. and Studie se zabývá neurčitostí, stabilitou a robustností při operativním řízení nádrží. Tyto vlastnosti řízení se dnes stávají novými hledisky při využívání vodních zdrojů a jejich soustav v měnících se podmínkách. Studie vychází z moderní teorie řízení dynamických systémů, objasňuje její cíle a matematickou náročnost metodických postupů. Místo analytických metod byly ve studii využity pro řešení stability odtoku z nádrží za povodňových situací simulační modely. Ochranný účinek nádrže se řešil variantně na podkladě souborů generovaných syntetických povodňových vln. Stabilita odtoku se tak mohla zkoumat v různých hydrologických situacích. Studie dospěla k závěru, že stabilitu odtoku u vybudovaných nádrží lze zabezpečit zpravidla jen v jistých mezích, v katastrofálních situacích je tento požadavek nereálný. Účelná je tu kombinace různých protipovodňových opatření, např. většího ochranného prostoru nádrže, předvypouštění z nádrže, prohloubení hydrometeorologické předpovědi, úpravy koryta pod nádrží a j. Studie uvádí v závěru náměty na další výzkum v této oblasti.
The second part of the study presents the results of the control stability judgement of the Lipno reservoir in the flood situations. For this solution were used the generated synthetic flood waves. This part is the continuation of the first part with methodology, published in 1/2008 of the JHH. and Tato část studie uvádí výsledky posouzení stability řízení nádrže Lipno za povodňových situací. K tomu byly využity soubory generovaných syntetických povodňových vln. Navazuje na první část s metodickými postupy, publikovanou v č. 1/2008 Journal of Hydrology and Hydromechanics.
Knowledge of the distribution of plant roots in a soil profile (i.e. root density) is needed when simulating root water uptake from soil. Therefore, this study focused on evaluating barley and wheat root densities in a sand-vermiculite substrate. Barley and wheat were planted in a flat laboratory box under greenhouse conditions. The box was always divided into two parts, where a single plant row and rows cross section (respectively) was simulated. Roots were excavated at the end of the experiment and root densities were assessed using root zone image processing and by weighing. For this purpose, the entire area (width of 40 and height of 50 cm) of each scenario was divided into 80 segments (area of 5x5 cm). Root density in each segment was expressed as a root percentage of the entire root cluster. Vertical root distributions (i.e. root density with respect to depth) were also calculated as a sum of root densities in each 5 cm layer. Resulting vertical root densities, measured evaporation from the water table (used as the potential root water uptake), and the Feddes stress response function model were used for simulating substrate water regime and actual root water uptake for all scenarios using HYDRUS-1D. All scenarios were also simulated using HYDRUS-2D. One scenario (areal root density of barley sown in a single row, obtained using image analysis) is presented in this paper (because most scenarios showed root water uptakes similar to results of 1D scenarios). The application of two root detecting techniques resulted in noticeably different root density distributions. Differences were mainly attributed to the fact that fine roots of high density (located mostly at the deeper part of the box) had lower weights in comparison to the weight of few large roots (at the box top). Thus, at the deeper part, higher root density (with respect to the entire root zone) was obtained using the image analysis in comparison to that from the gravimetric analysis. Conversely, lower root density was obtained using the image analysis at the upper part in comparison to that from the gravimetric analysis. On the other hand, fine roots overlapped each other and therefore were not visible in the image, which resulted in lower root density values from image analysis. Root water uptakes simulated with HYDRUS-1D using diverse root densities obtained for each cereal declined differently from the potential root water uptake values depending on water scarcity at depths of higher root density. and Usually, an earlier downtrend associated with gradual root water uptake decreases and vice versa. Similar root water uptakes were simulated for the presented scenario using the HYDRUS1D and HYDRUS-2D models. The impact of the horizontal root density distribution on root water uptake was, in this case, less important than the impact of the vertical root distribution resulting from different techniques and sowing scenarios.