Journal articles on the topic 'Tidal basins Mathematical models'
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R., Bustami, Hong C., and Lim D. "River Bedup Catchment Water Level Prediction Using Pre-developed ANN Model of Siniawan Catchment." Journal of Civil Engineering, Science and Technology 2, no. 1 (March 1, 2011): 36–41. http://dx.doi.org/10.33736/jcest.86.2011.
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This study proposes the application of Artificial Neural Network (ANN) in the prediction of hourly water level under tidal influence for Sadong Basin. An ANN is undoubtedly a robust tool for forecasting various non-linear hydrologic processes, including the water level prediction. It is a flexible mathematical structure which is capable to generalize patterns in imprecise or noisy and ambiguous input and output data sets. In this study, ANN models were developed specifically to forecast the hourly water level for River Bedup Station. Distinctive networks were trained, validated and simulated using hourly data obtained from Department of Irrigation and Drainage, Sarawak in Kuching. The performances of ANN were evaluated based on the coefficient of efficiency, E2 and the coefficient of correlation, R. The back propagation algorithm was adopted for this study. Models used in this study is trained, validated and simulated with scaled conjugate gradient algorithm (trainscg) with two hours of antecedent data, learning rate and the number of neurons in the hidden layer of 0.8 and 40 respectively. In this study, the models generated an accuracy of 100% for all training, validating and simulating stages. It has been found that the ANN has the potential to solve the problems of water level prediction.
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FEDORCHUK, A. "Analysis of modern models of counterfeiting surfaces for determination of heights by GNSS-leveling method." Modern achievements of geodesic science and industry 2, no. 44 (September 1, 2022): 31–41. http://dx.doi.org/10.33841/1819-1339-2-44-31-41.
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This paper discusses various sources of information related to the issue of determining heights by GNSS-leveling. Implementation of the GNSS leveling method requires the presence of geoid or quasi-geoid heights, which today can be obtained from the corresponding models. In recent decades, scientists from around the world have developed many global, regional and local models of geoid and quasigeoid. This has contributed to the emergence of numerous publications on GNSS leveling. The purpose of the work is to perform the analysis of modern models of reference surfaces on the basis of materials of scientific publications according to the criteria that have a significant impact on research in the field of determining the height by GNSS-leveling. Method. The paper considers 44 publications published in the period 2001–2021. Among the research in this direction, there are three types of work: 1) 13 publications on methods of constructing the models themselves; 2) 12 works on their accuracy analysis and 3) 19 works on “adjustment” of model heights. At the first stage of the research the analysis was performed according to criteria related to geoid and quasi-geoid surface modeling, including Stokes and Molodensky theory, mathematical methods of data analysis and processing, tidal systems, zero-order geoid undulation and scale levels of geoid and quasi-geoid models. In the second stage, the frequency of publications by years was analyzed and the activity of publications of existing geoid and quasigeoid models on the sample of countries, which was made on the basis of all selected works in this study, was established. At the third stage, a quantitative analysis of official published models of geoid and quasi-geoid on the frequency of publications for the study period. The ratio of the accuracy of the heights of global geoid models in relation to the magnitude of the degree and order of their calculation is established. Results. In 58 % of the analyzed works, the authors use Stokes’ theory in their research, and in 42 % – Molodensky’s theory. Among the mathematical methods of data analysis and processing, 27 % use the method of mean square collocation, 20 % use the least squares method, the “delete-restore” method and the method of modifying Stokes’ formula with least squares (or KTH-method). The Fast Fourier transform method was used in 13 % of the works. Publications on the creation of global models of the Earth mostly use the parameters of the tide free tidal system in their calculations – a total of 40 % works. No less important criterion (33 % of works) should be taken into account the parameter of undulation of the geoid of zero order (“zero degree term”). In total, 41 % of research is aimed at creating and analyzing quasi-geoid models on a regional scale. During the study period, most works were published in 2012 and 2018. Leading countries in the development of quasi-geoid models are Canada, Poland, Sweden and the United States, and global geoid models are Germany, the United States and China. For the period 2001–2021, 99 global geoid models of various degree and order were officially presented, among which GOCO, EIGEN and EGM series models are most often used for research. Also during this period, 177 quasi-geoid models were presented, the most of which were published in 2019. Based on these data, the relationship with the frequency of publications in 2008–2021 can be traced. The accuracy of global geoid models in relation to the degree and order of their calculation is systematic in the range of 0.52–1.92 m, 0.38–0.50 m, 0.23–0.38 m and 0.12–0,14 m for models 60-220, 220-260, 260-720 and 720-2190 degree and order respectively. Scientific novelty. It is shown that the analysis of modern models of reference surfaces on the basis of materials of scientific publications in the field of GNSS-leveling method allows establishing the existing advantages and disadvantages of research in this field. Practical significance. The data of such analysis can be used to solve key problems in determining the height of the GNSS-leveling method, which require further research and to find modernized solutions.
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Ellis, Kathryn K., Timothy Callahan, Dianne I. Greenfield, Denise Sanger, Joshua Robinson, and Martin Jones. "Measuring and Modeling Flow Rates in Tidal Creeks: A Case Study from the Central Coast of South Carolina." Journal of South Carolina Water Resources, no. 4 (June 1, 2017): 21–39. http://dx.doi.org/10.34068/jscwr.04.03.
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The purpose of this study was to collect site- and condition-specific hydrology data to better understand the water flow dynamics of tidal creeks and terrestrial runoff from surrounding watersheds. In this paper, we developed mathematical models of tidal creek flow (discharge) in relation to time during a tidal cycle and also estimated terrestrial runoff volume from design storms to compare to tidal creek volumes. Currently, limited data are available about how discharge in tidal creeks behaves as a function of stage or the time of tide (i.e., rising or falling tide) for estuaries in the southeastern United States, so this information fills an existing knowledge gap. Ultimately, findings from this study will be used to inform managers about numeric nutrient criteria (nitrogen-N and phosphorus-P) when it is combined with biological response (e.g., phytoplankton assemblages) data from a concurrent study. We studied four tidal creek sites, two in the Ashepoo-Combahee-Edisto (ACE) Basin and two in the Charleston Harbor system. We used ArcGIS to delineate two different watersheds for each study site, to classify the surrounding land cover using the NOAA Coastal Change Analysis Program (C-CAP) data, and to analyze the soils using the NRCS Soil Survey Geographic database (SSURGO). The size of the U.S. Geological Survey’s Elevation Derivatives for National Application (EDNA) watersheds varied from 778 to 2,582 ha; smaller geographic watersheds were delineated for all sites (except Wimbee) for stormwater modeling purposes. The two sites in Charleston Harbor were within the first-order Horlbeck Creek and the second-order Bulls Creek areas. The ACE Basin sites were within the third-order Big Bay Creek and the fourth-order Wimbee Creek areas. We measured the stage and discharge in each creek with an acoustic Doppler current profiler (ADCP) unit for multiple tide conditions over a 2-year period (2015–2016) with the goal of encompassing as large of a range of tide stage and discharge data measurements as possible. The Stormwater Runoff Modeling System (SWARM) was also used to estimate the potential water entering the creeks from the land surface; this volume was very small relative to the tide water volume except for the more-developed Bulls Creek watershed. The results show that the peak discharge occurred on the ebb tide and that the duration of the flood tide spanned a longer period of time; both of these observations are consistent with traits associated with an ebb-dominated tidal creek system. The tidal inflow and outflow (flood and ebb tides, respectively) showed an asymmetrical pattern with respect to stage and discharge; peak discharge during the flood (rising) tide occurred at a higher stage than for the peak discharge during the ebb (falling) tide. This is not an unexpected result, as the water on an ebb tide is moving down gradient funneled through the creek channel toward the coast. Furthermore, water moving with the rising flood tide must overcome frictional losses due to the marsh bank and vegetation; i.e., the peak discharge can only happen when the water has risen above these impediments. We infer from the flow dynamics data that faster water velocities during ebb tide imply that more erosive energy could transport a larger mass of suspended solids and associated nutrients (e.g., orthophosphate) from the estuary to the coastal ocean. However, the discharge and runoff modeling indicate that land-based flux was important in the developed Bulls Creek watershed, but not at the larger and less-developed Big Bay Creek watershed. At Big Bay Creek, the relatively large tidal discharge volume compared to the smaller potential runoff generated within the watershed indicates that the creek could potentially dilute terrestrial runoff contaminants. Smaller, more-urbanized tidal wetland systems may not benefit from such dilution effects and thus are vulnerable to increased runoff from adjacent developed landscapes.
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Wang, Zheng Bing, Edwin P. L. Elias, Ad J. F. van der Spek, and Quirijn J. Lodder. "Sediment budget and morphological development of the Dutch Wadden Sea: impact of accelerated sea-level rise and subsidence until 2100." Netherlands Journal of Geosciences 97, no. 3 (September 2018): 183–214. http://dx.doi.org/10.1017/njg.2018.8.
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AbstractThe Wadden Sea is a unique coastal wetland containing an uninterrupted stretch of tidal flats that span a distance of nearly 500km along the North Sea coast from the Netherlands to Denmark. The development of this system is under pressure of climate change and especially the associated acceleration in sea-level rise (SLR). Sustainable management of the system to ensure safety against flooding of the hinterland, to protect the environmental value and to optimise the economic activities in the area requires predictions of the future morphological development.The Dutch Wadden Sea has been accreting by importing sediment from the ebb-tidal deltas and the North Sea coasts of the barrier islands. The average accretion rate since 1926 has been higher than that of the local relative SLR. The large sediment imports are predominantly caused by the damming of the Zuiderzee and Lauwerszee rather than due to response to this rise in sea level. The intertidal flats in all tidal basins increased in height to compensate for SLR.The barrier islands, the ebb-tidal deltas and the tidal basins that comprise tidal channels and flats together form a sediment-sharing system. The residual sediment transport between a tidal basin and its ebb-tidal delta through the tidal inlet is influenced by different processes and mechanisms. In the Dutch Wadden Sea, residual flow, tidal asymmetry and dispersion are dominant. The interaction between tidal channels and tidal flats is governed by both tides and waves. The height of the tidal flats is the result of the balance between sand supply by the tide and resuspension by waves.At present, long-term modelling for evaluating the effects of accelerated SLR mainly relies on aggregated models. These models are used to evaluate the maximum rates of sediment import into the tidal basins in the Dutch Wadden Sea. These maximum rates are compared to the combined scenarios of SLR and extraction-induced subsidence, in order to explore the future state of the Dutch Wadden Sea.For the near future, up to 2030, the effect of accelerated SLR will be limited and hardly noticeable. Over the long term, by the year 2100, the effect depends on the SLR scenarios. According to the low-end scenario, there will be hardly any effect due to SLR until 2100, whereas according to the high-end scenario the effect will be noticeable already in 2050.
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Li, Wen Dan, and Meng Guo Li. "Suspension-Diffusion Mathematical Model Calculation for Wenzhou Shoal in Construction Period." Advanced Materials Research 1065-1069 (December 2014): 453–56. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.453.
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By means of natural condition and mathematical models of tidal flow and sediment, numerical study is carried out on suspension-diffusion in construction period after the reclamation project of Wenzhou shoal at Oujiang estuary in this paper. The main conclusions are: the suspension-diffusion is controlled by tidal current. The range of suspended sediment concentration more than 10mg/L is mostly in Wenzhou shoal area during filling sand construction, which is the continuous operation. Riprap construction is Instantaneous work; the range of scatter is limited.
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Lim, Sin Liang, and B. S. Daya Sagar. "Derivation of Geodesic Flow Fields and Spectrum in Digital Topographic Basins." Discrete Dynamics in Nature and Society 2008 (2008): 1–26. http://dx.doi.org/10.1155/2008/312870.
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We present a framework to characterize terrestrial functions—surficial and bottom topographic regions that are represented, respectively, as raster digital elevation models (DEMs) and digital bathymetric models (DBMs)—through analysis of flow fields that are simulated via geodesic morphology. Characterization of such functions is done via a new descriptor. Computation of this new descriptor involves the following steps: (i) basin in digital form representing topographic fluctuations as an input, (ii) threshold decomposition of basin—that consists of channelized and nonchannelized regions—into sets, (iii) proper indexing of these sets to decide the marker set(s) and its (their) corresponding mask set(s), (iv) performing geodesic propagation that provides basic flow field structures, and (v) finally providing a new basin descriptor—geodesic spectrum. We demonstrated this five-step framework on five different synthetic and/or realistic DEMs and/or DBMs. This study provides potentially invaluable insights to further study the travel-time flood propagation within basins of both fluvial and tidal systems.
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Côté, Jessica, and Kathryn Ketteridge. "TIDAL CHANNEL GEOMETRY OF BARRIER EMBAYMENT SYSTEMS IN PUGET SOUND." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 76. http://dx.doi.org/10.9753/icce.v36.currents.76.
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This paper will present the first year of findings from a research project with the objective of producing empirically based models of tidal channel characteristics that can be broadly applied to design estuary restoration projects in Puget Sound. A combination of field data collection methods and desktop analysis are being utilized to calculate tidal prism, channel dimensions, marsh extent, and water surface elevations to parameterize well-functioning barrier embayments in Puget Sound. The tidal channel data will be used to conduct a regression analysis and develop hydraulic geometry scaling relationships. The goal of the study is to develop one set of regression lines for the Puget Sound basin; however, if the data collection reveals important differences between sub-basins, then two or more regressions may be developed. For example, Hood (2015) found wave exposure contributed to differences in tidal channel geometry in the major river deltas within Puget Sound. Differences in wave exposure and tide range among the sub-regions of Puget Sound could create a need for creating more than one set of scaling relationships (e.g. North Sound and South Sound).
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Yiew, Lucas J., and Allan R. Magee. "Deriving tidal currents from AIS data." Journal of Physics: Conference Series 2311, no. 1 (July 1, 2022): 012003. http://dx.doi.org/10.1088/1742-6596/2311/1/012003.
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Abstract In this study, a method is proposed to derive ocean surface current conditions using only information available through AIS – mainly speed over ground (SOG), course over ground (COG) and vessel heading. This method allows the mapping of current conditions over large areas, in doing so gives seafarers better awareness and advance warning of local environmental conditions. This also helps in route planning and management of voyage-related resources. In the proposed method, current speeds and directions are solved through a system of equations containing the resolved SOG, COG and heading of multiple ships. This method was tested using mathematical manoeuvring models, and then subsequently using AIS data collected from vessel traffic in the Western Singapore Straits. Current predictions using this method are validated against physics-based depth-averaged hydrodynamic models driven by astronomical tidal forcing.
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Yu, Feng, and Yong Yin. "Oil Spill Visualization Based on the Numeric Simulation of Tidal Current." International Journal of Virtual Reality 8, no. 2 (January 1, 2009): 71–74. http://dx.doi.org/10.20870/ijvr.2009.8.2.2727.
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This paper proposes an approach to implement the 3D visualization of oil spill based on tidal hydrodynamic model. It simulates tidal current of M2 component tide in Jiaozhou Bay. The simulation results conform to the tidal theory and probably conform to the flow measurement report of crude oil pier Phase III at Qingdao Harbor. Based on tidal current and eye-point related adaptive ocean surface mesh model, by analyzing the drift and diffusion mathematical models of oil spill on the sea, the dynamic visualization of drift and diffusion course of oil on the sea were implemented, the visualization result is satisfactory.
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Savvidis, Y. G., C. G. Koutitas, and Y. N. Krestenitis. "Modelling the water mass exchange through navigational channels connecting adjacent coastal basins - application to the Channel of Potidea (North Aegean Sea)." Annales Geophysicae 23, no. 2 (February 28, 2005): 231–38. http://dx.doi.org/10.5194/angeo-23-231-2005.
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Abstract. The research objective is the detection of the mechanism of the water mass exchange through a navigational channel connecting two adjacent coastal basins. The research involves the application of a mathematical model in parallel to in-situ measurements. The hydrodynamic circulation in the greater area of the NW Aegean Sea is modeled by means of a barotropic circulation model. Wind, Coriolis and Tide are the main forcings taken into account. The flow through the channel is resolved at a subgrid scale by means of a local open channel flow model. The comparison between field measurements, recorded during a limited period, and the model results supports the model verification. The study is integrated by an operational application of the model under various realistic forcings. The results help to gain a better understanding of the mechanisms regulating the water mass exchange and the consequent interaction between two adjacent connected coastal basins. From the case study of the Potidea channel it is revealed that the water mass exchange under mean wind forcing is of the same order as the one induced by the tidal forcing.
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Cárdenas Gutiérrez, Javier Alfonso, Jose Leonardo Jacome Carrascal, and Mawency Vergel Ortega. "Determination of potential and actual evapotranspiration in watershed, using mathematical models." Revista Boletín Redipe 10, no. 3 (March 1, 2021): 225–31. http://dx.doi.org/10.36260/rbr.v10i3.1230.
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In this research, it is analyzed the calculation of real evapotranspiration in hydrographic basins, it is taken as a reference the Aguablanca Creek, located in the municipality of Bochalema, North of Santander-Colombia, where it is evaluated the hydrologic balance of this basin from the determination of detailed calculations of four mathematical models, to later evaluate the hydrologic balance of this basin, with the purpose of being able to make a better administration of these resources, as well as the use of the soil, betting on the development of an ecologically sustainable society with low environmental impact. The values of potential and real evapotranspiration, according to the most optimal model ETP Thorwaite 874 mm/year ETR 43712 mm/year, Cenicafe 712.81 mm/year ETR 612.1 mm/year Turc ETR 884.83 mm/year quota ETR 825 mm/year.
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Murphy, Enda, Mathieu Deiber, and Sylvain Perrin. "SHEAR-DRIVEN FLUSHING OF MICRO-TIDAL MARINAS." Coastal Engineering Proceedings 1, no. 33 (December 15, 2012): 59. http://dx.doi.org/10.9753/icce.v33.currents.59.
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Flushing or residence times are typically used as a first step in assessing water quality in marinas, harbours and coastal basins. Recent publications have offered guidance in relation to optimal marina basin and entrance geometries to help achieve rapid renewal. However, these guidelines have been developed for the particular case where water exchange is strongly tide-driven and are not widely applicable, particularly in micro-tidal regions. Where water renewal rates are dominated by shear-driven circulation and lateral transfer of momentum at the interface between the marina and the adjacent water body (i.e. a mixing layer), there is a strong analogy to groyne fields and other cases involving flows containing quasi-stagnant peripheral areas (dead zones). A series of numerical hydrodynamic models, developed in the TELEMAC system, were used to investigate the potential for the dead zone model of water exchange to provide a
better means to guide optimization of basin and entrance geometry under such conditions. Real-world marina case
studies were used to identify any constraints affecting the practical implementation of such an approach. The numerical model results demonstrate particular conditions under which the dead zone model of water exchange can be used effectively to optimize marina basin and entrance geometry.
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Hadi, Safwan, Arthur J. Hanson, Koesoebiono, Musrefinah Mahlan, Mulia Purba, and Santoso Rahardjo. "TIDAL PATTERNS AND RESOURCE USE IN THE MUSI-BANYUASIN COASTAL ZONE OF SUMATRA." Marine Research in Indonesia 19 (May 10, 2018): 109–35. http://dx.doi.org/10.14203/mri.v19i0.376.
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Tidal influence extends 100 km upriver in the coastal swamplands of Sumatra and Kalimantan. In planning development or resource use, description of local tidal variation is important since tides interact with river flow to zone the land and waters into a series of distinctive environments. The coastal swamps are being opened for rice cultivation with tidally-influenced irrigation and drainage canals. There are also forestry and fishery activities plus major shipping activities in these delta areas. The tidal patterns arc studied in the South Sumatra coastal portion of the Musi and Banyuasin River basins. The tides are mixed, predominantly diurnal with a maximum range of 3.5 m near the coast. Significant differences in tidal amplitude and phase exist between rivers separated by deltas often less than 10 km in width. Differences in river water flow atributed to season or basin characteristics influence tidal patterns. On the Musi river the relationship between tidally-influenced resource uses and distance from the sea suggests the greatest variety of activities occurs within the zone of maximum tidal range 0 to 30 km from the delta fronts. This zone should therefore be considered a region of special ecological concern. A mechanism is needed for coordinated planning of infrastructure changes likely to influence hydrology or resource uses. Predictive models should be developed for measuring the likely impact of such development on coastal hydrology.
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CHOQUET, CATHERINE. "PARABOLIC AND DEGENERATE PARABOLIC MODELS FOR PRESSURE-DRIVEN TRANSPORT PROBLEMS." Mathematical Models and Methods in Applied Sciences 20, no. 04 (April 2010): 543–66. http://dx.doi.org/10.1142/s0218202510004337.
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We consider two models of flow and transport in porous media, the first one for consolidational flow in compressible sedimentary basins, the second one for flow in partially saturated media. Despite the differences in these physical settings, they lead to quite similar mathematical models with a strong pressure coupling. The first model is a coupled system of pde's of parabolic type. The second one involves a coupled system of pdes of degenerate parabolic–hyperbolic type. We state an existence result of weak solutions for both models.
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Hernandez, E. S., and D. M. Jezek. "Determination of basins of attraction for SU(2) dissipative models." Journal of Physics A: Mathematical and General 21, no. 13 (July 7, 1988): 2899–909. http://dx.doi.org/10.1088/0305-4470/21/13/014.
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Gardner, E. "Optimal basins of attraction in randomly sparse neural network models." Journal of Physics A: Mathematical and General 22, no. 12 (June 21, 1989): 1969–74. http://dx.doi.org/10.1088/0305-4470/22/12/002.
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Li, Wei, and Zhenghua Su. "EFFECTS OF HYPERCONCENTRATION-RELATED DRAG REDUCTION ON TIDAL PROPAGATION IN THE QIANTANG ESTUARY." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 70. http://dx.doi.org/10.9753/icce.v36.currents.70.
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The Qiantang Estuary (QE) in the east coast of China is famous for its hyperconcentrated tidal bore with the highest sediment concentration up to about 80 kg/m3 (Pan et al., 2013). Recent research for some European estuaries has indicated that hyperconcentrated environment may affect tidal propagation through hydraulic drag reduction, resulting in an enlarged tidal range and even a regime shift in the estuary (Winterwerp and Wang, 2013). However, this water-sediment interactions have not been considered in the tidal prediction of the Qiantang Estuary in the past. Instead, a bed roughness even smaller than that of glossy glass has often been used to fit the observed tidal data in the mathematical modelling.
Therefore, the present study aims to reveal whether the hyperconcentration-related drag reduction can explain the mechanism of very small bed roughness in the Qiantang Estuary and to what extent it can affect the tidal propagation especially for the tidal range. First, an analytical model is used to predict the tidal range along the QE (from Wenyan to Ganpu stations) for different methods of bed friction. Then, mathematical modelling is conducted to shed light on the processes of tidal wave propagation for the corresponding approaches. The results of the two models are compared together with the field observations to further verify the ability of the analytical model and the significance of the effects of hyperconcentration-related drag reduction.
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Mańko, Robert, and Norbert Laskowski. "Comparative analysis of the effectiveness of the conceptual rainfall-runoff hydrological models on the selected rivers in Odra and Vistula basins." ITM Web of Conferences 23 (2018): 00025. http://dx.doi.org/10.1051/itmconf/20182300025.
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Identification of physical processes occurred in the watershed is one of the main tasks in hydrology. Currently the most efficient hydrological processes describing and forecasting tool are mathematical models. They can be defined as a mathematical description of relations between specified attributes of analysed object. It can be presented by: graphs, arrays, equations describing functioning of the object etc. With reference to watershed a mathematical model is commonly defined as a mathematical and logical relations, which evaluate quantitative dependencies between runoff characteristics and factors, which create it. Many rainfall-runoff linear reservoirs conceptual models have been developed over the years. The comparison of effectiveness of Single Linear Reservoir model, Nash model, Diskin model and Wackermann model is presented in this article.
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Paterson, Lincoln. "A REVIEW OF COMPUTER MODELS TO CHARACTERISE HETEROGENEITY IN PETROLEUM BASINS." APPEA Journal 33, no. 1 (1993): 322. http://dx.doi.org/10.1071/aj92023.
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Heterogeneity is a major problem in the evaluation of petroleum reservoirs. Yet the search for oil requires increasingly complex reservoirs to be evaluated. It is often necessary to interpolate sparse data, which may be performed inaccurately.One approach to this problem has resulted in the development of a number of computer models that produce statistically correct interpolation of data. Two types of models exist, namely process and response. Process models attempt to build sedimentary formations from the physical processes involved in deposition, such as aggradation, avulsion, compaction and tectonism. Response models are founded on existing data, and use purely mathematical techniques to interpolate values, such as kriging and fractal methods.It is the aim of this paper to review these computer models for description of stratal geometries in petroleum basins, pointing out their strengths and weaknesses. Most of the process models have historically focussed on marine clastics and carbonate deposits, and are limited to two dimensions, or treat the third dimension simplistically. Response models on the other hand do not consider depositional processes, and have tended to smooth the data. Fractal statistics have attempted to overcome the smoothing problem, but many formations do not appear to be described by simple fractals.Compared to other topics in numerical simulation, modelling of sedimentary deposition is in its infancy. However, great opportunities exist to make significant developmental advances. Adequate description of reservoir geometry should improve success rates in exploration and assist in development strategies.
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Sukhinov, A., A. Chistyakov, S. Protsenko, and E. Protsenko. "Study of 3D discrete hydrodynamics models using cell filling." E3S Web of Conferences 224 (2020): 02016. http://dx.doi.org/10.1051/e3sconf/202022402016.
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Modern methods and tools for coastal hydrodynamics modeling indicate the necessity of constructing discrete analogs of models for ones the properties: balance and conservation laws (for mass, flows, impulse), stability, convergence and etc. have been fulfilled. The paper considers a continuous three-dimensional mathematical model of the hydrodynamics of water basins and its discretization. The pressure correction method at variable water medium density was used to solve the problem of hydrodynamics. The considered discrete mathematical models of hydrodynamics take into account the filling of control cells on rectangular grids. This increased the accuracy of the solution in the case of complex geometry by improving the boundary approximation. From the obtained estimates of the components of the velocity vector, it follows that there are no two or more stationary regimes in which all forces are balanced, and the solution to the discrete problem exists and is unique and tends to the solution of the continuous problem upon reaching the stationary regime. Also the balance of the flows for the discrete model has been proved as well as absence of non-conservative dissipative terms.
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Kanakis-Pegios, Alkiviadis, and Charalampos Moustakidis. "Constraints on neutron stars equation of state using the tidal deformability derived from BNS mergers." HNPS Proceedings 27 (April 17, 2020): 95. http://dx.doi.org/10.12681/hnps.2989.
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The purpose of this work is the study of neutron stars (NS) equation of state (EOS) using constraints on tidal deformability derived from observation of binary neutron star (BNS) mergers, such as GW170817. The mathematical formalism is introduced, and then for a variety of EOS the system is solved numerically, allowing us to determine the mass, the radius, the tidal love number and the tidal deformability of the NS, each one of them unique for each EOS. Moreover, for a fixed value of chirp mass under the assumption that m2<m1 (where m1 is the heavier component mass of BNS system), the effective (mass-weighted) tidal deformability of the binary system is determined for each EOS. We consider both an upper limit (GW170817) and a lower limit (AT2017gfo) for the effective tidal deformability. Also, we construct the Λ1-Λ2 space and we compare the behavior of EOS with the most recent LIGO’s data. We found out that the most EOS models give values for the effective tidal deformability less than the upper limit and that the most stiff EOS are excluded.
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SCHÄFER, BJÖRN MALTE. "GALACTIC ANGULAR MOMENTA AND ANGULAR MOMENTUM CORRELATIONS IN THE COSMOLOGICAL LARGE-SCALE STRUCTURE." International Journal of Modern Physics D 18, no. 02 (February 2009): 173–222. http://dx.doi.org/10.1142/s0218271809014388.
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I review the theory of angular momentum acquisition of galaxies by tidal torquing, the resulting angular momentum distribution and the angular momentum correlation function, and discuss the implications of angular momentum alignments for weak lensing measurements. Starting from linear models for tidal torquing, I summarize perturbative approaches and the results from n-body simulations of cosmic structure formation. Then I discuss the validity of decompositions of the tidal shear and inertia fields, the effects of angular momentum biasing, the applicability of parametrized angular momentum correlation models and the consequences of angular momentum correlations for shape alignments. I compile the results of observations of shape alignments in recent galaxy surveys as well as in n-body simulations. Finally, I review the contamination of weak lensing surveys by spin-induced shape alignments and methods for suppressing this contamination.
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Chen, Anqing, Shenglin Xu, Shuai Yang, Hongde Chen, Zhongtang Su, Yijiang Zhong, and Sihan Hu. "Ordovician deep dolomite reservoirs in the intracratonic Ordos Basin, China: Depositional model and Diagenetic evolution." Energy Exploration & Exploitation 36, no. 4 (May 23, 2018): 850–71. http://dx.doi.org/10.1177/0144598718778171.
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Recent natural gas discoveries indicate that non-karstification-dominated reservoirs exist in the intracratonic Ordos Basin. This study examines the sedimentological and geochemical characteristics needed to clarify the depositional model and diagenetic evolution process of this newly discovered reservoir type. The depositional environment of the dolomite reservoir can be characterized as a tidal flat that grew from the Central Paleo-uplift to the eastern depression by cyclic progradation on an epeiric platform. A tidal flat sequence can extend laterally as a progradational wedge in each cycle of sea level fluctuation. The sheet-shaped peritidal shoal facies associations patched on the wedge represent potential dolomite reservoirs and can be recognized by the presence of doloarenite that has been altered into a vaguely relict grained-texture by diagenesis. Although continuing destructive diagenesis has led to reservoir densification, burial dolomitization and burial dissolution with facies selectivity have tended to occur in peritidal shoal facies associations, thus improving the quality of the dolomite reservoirs. These models provide new insights for targeting deep dolomite hydrocarbon reservoirs in intracratonic basins.
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Pani, Paolo, and Andrea Maselli. "Love in extrema ratio." International Journal of Modern Physics D 28, no. 14 (October 2019): 1944001. http://dx.doi.org/10.1142/s0218271819440012.
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The tidal deformability of a self-gravitating object leaves an imprint on the gravitational-wave signal of an inspiral which is paramount to measure the internal structure of the binary components. We unveil here a surprisingly unnoticed effect: in the extreme mass-ratio limit the tidal Love number of the central object (i.e. the quadrupole moment induced by the tidal field of its companion) affects the gravitational waveform at the leading order in the mass ratio. This effect acts as a magnifying glass for the tidal deformability of supermassive objects but was so far neglected, probably because the tidal Love numbers of a black hole (the most natural candidate for a compact supermassive object) are identically zero. We argue that extreme mass-ratio inspirals detectable by the future laser interferometric space antenna (LISA) mission might place constraints on the tidal Love numbers of the central object which are roughly eight orders of magnitude more stringent than current ones on neutron stars, potentially probing all models of black hole mimickers proposed so far.
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Li, Wen Dan, and Meng Guo Li. "Effectiveness Analysis of Promoting Deposition for Submerged Dike in Wenzhou Shoal." Advanced Materials Research 1065-1069 (December 2014): 449–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.449.
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By means of natural condition、scour and silting evolution and mathematical models of wave, tidal flow and sediment, numerical study is carried out on deposit-promoting schemes in the reclamation project of Wenzhou shoal at Oujiang estuary in this paper. The main conclusions are:The scouring and silting reached equilibrium is 0.1~1.2 m in west side and 0.1~0.9 m in east side.
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Melet, Angélique, Sonya Legg, and Robert Hallberg. "Climatic Impacts of Parameterized Local and Remote Tidal Mixing." Journal of Climate 29, no. 10 (April 28, 2016): 3473–500. http://dx.doi.org/10.1175/jcli-d-15-0153.1.
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Abstract Turbulent mixing driven by breaking internal tides plays a primary role in the meridional overturning and oceanic heat budget. Most current climate models explicitly parameterize only the local dissipation of internal tides at the generation sites, representing the remote dissipation of low-mode internal tides that propagate away through a uniform background diffusivity. In this study, a simple energetically consistent parameterization of the low-mode internal-tide dissipation is derived and implemented in the Geophysical Fluid Dynamics Laboratory Earth System Model with GOLD component (GFDL-ESM2G). The impact of remote and local internal-tide dissipation on the ocean state is examined using a series of simulations with the same total amount of energy input for mixing, but with different scalings of the vertical profile of dissipation with the stratification and with different idealized scenarios for the distribution of the low-mode internal-tide energy dissipation: uniformly over ocean basins, continental slopes, or continental shelves. In these idealized scenarios, the ocean state, including the meridional overturning circulation, ocean ventilation, main thermocline thickness, and ocean heat uptake, is particularly sensitive to the vertical distribution of mixing by breaking low-mode internal tides. Less sensitivity is found to the horizontal distribution of mixing, provided that distribution is in the open ocean. Mixing on coastal shelves only impacts the large-scale circulation and water mass properties where it modifies water masses originating on shelves. More complete descriptions of the distribution of the remote part of internal-tide-driven mixing, particularly in the vertical and relative to water mass formation regions, are therefore required to fully parameterize ocean turbulent mixing.
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Toda, Keiichi. "Urban Flooding and Measures." Journal of Disaster Research 2, no. 3 (June 1, 2007): 143–52. http://dx.doi.org/10.20965/jdr.2007.p0143.
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Urban flood disasters occur often worldwide, and Japan is no exception, as indicated by the 1999 Fukuoka flood. Urban floods result from changes in the urban environment influenced by the specific features of the city involved. We review recent urban floods, their causes and characteristics, together with the results of recent studies. Focusing on two mathematical models -- the integrated urban flood model of urban river basins and the underground inundation model -- we discuss their simulation results. To demonstrate the dangers of underground inundations, we introduce evacuation experiments conducted using full-scale staircase and door models. Based on these studies, we propose comprehensive measures against urban floods, including underground inundations.
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Lampe, C., M. Person, S. Noth, and W. Ricken. "Episodic fluid flow within continental rift basins: some insights from field data and mathematical models of the Rhinegraben." Geofluids 1, no. 1 (February 2001): 42–52. http://dx.doi.org/10.1046/j.1468-8123.2001.11005.x.
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Schuerch, Mark, Tobias Dolch, Karsten Reise, and Athanasios T. Vafeidis. "Unravelling interactions between salt marsh evolution and sedimentary processes in the Wadden Sea (southeastern North Sea)." Progress in Physical Geography: Earth and Environment 38, no. 6 (September 12, 2014): 691–715. http://dx.doi.org/10.1177/0309133314548746.
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Salt marshes in the Wadden Sea constitute about 20% of all salt marshes along European coasts. They are of immense importance for coastal protection reasons and as habitat for coastal plant, bird, and invertebrate species. The Wadden Sea is a coastal sedimentary ecosystem in the southeastern North Sea. Besides salt marshes, it is composed of tidal flats, high sands, and sandy shoals, dissected by (sub)tidal channels and located behind barrier islands. Accelerated global sea-level rise (SLR) and changes in storm climate have been identified as possible threats for the persistence of the Wadden Sea ecosystem including its salt marshes. Moreover, it is known that the amount and composition of the sediment available for salt marshes are the most important parameters influencing their ability to adapt to current and future SLR. Assessing these parameters requires a thorough understanding of the sedimentary system of the salt marshes and the adjacent tidal basins. In the present review, we investigate and unravel the interactions of sedimentary processes in the Wadden Sea with the processes taking place on the salt marshes. We identify the most crucial processes and interactions influencing the morphological development of salt marshes in the Wadden Sea. A conceptual model is proposed, intended as a framework for improved understanding of salt marsh development and for incorporation into new salt marsh models. The proposed model may also be applicable to regions other than the Wadden Sea.
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Koycegiz, Cihangir, Meral Buyukyildiz, and Serife Yurdagul Kumcu. "Spatio-temporal analysis of sediment yield with a physically based model for a data-scarce headwater in Konya Closed Basin, Turkey." Water Supply 21, no. 4 (January 19, 2021): 1752–63. http://dx.doi.org/10.2166/ws.2021.016.
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Abstract There are many empirical, semi-empirical and mathematical methods that have been developed to estimate sediment yield by researchers. In the last decades, the advancement in computer technologies has increased the use of mathematical models as they can solve the system more rapidly and accurately. The Soil and Water Assessment Tool (SWAT) is one of the physically based hydrological models that is preferred to compute sediment yield. In this study, spatial and temporal analysis of sediment yield in the Çarşamba Stream located at the Konya Closed Basin has been investigated using the SWAT model. Streamflow and sediment data collected during the 2003–2015 time period have been used in the analysis. Consequently, the SWAT presented satisfactory results compared with R2 = 0.68, Nash–Sutcliffe Efficiency (NSE) = 0.68 in calibration and R2 = 0.76, NSE = 0.66 in validation. According to the model results, spatial asymmetry in terms of sediment yield was determined in the sub-basins of the study area.
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Kovalchuk, P. I., O. S. Demchuk, V. P. Kovalchuk, and Н. A. Balykhina. "Combined system of extreme control of mineralized water dilution in river basins." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 2 (December 23, 2021): 33–44. http://dx.doi.org/10.31073/mivg202102-296.
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The theory of combined systems of extreme control, which is used in technical systems, was developed and adapted in socio-ecological-economic systems. For example, river basins are such systems. A combined extreme control system has been formalized to control the dilution of mineralized mine waters in river sections. A mathematical model of the distribution of water masses and pollution in river beds from point and diffuse sources is proposed on the basis of a system of difference balance equations under the influence of stochastic uncontrolled disturbances. With regard to such conditions as adequate instrumentation, a combined control system has been developed that uses decision-making according to environmental and economic criteria based on the analysis of input and output data simultaneously, identification and tracking of the optimum in conditions of displacement under the influence of the disturbances of extreme characteristics of the system. The structural and functional diagram is represented by the open-loop diagram, the identification of which is carried out on the basis of modeling the process of water dilution in various situations at a specific object. A closed part with a recognition system as a corrector provides feedback. Formalized mathematical models of the dynamics of water masses and pollution from point and diffuse sources are of a general nature and can be used for the basins of other rivers. The extreme control system can adapt to the hydrological conditions and water quality parameters of a particular river.
A mathematical model has been formalized for the combined extreme control of mine water dilution in the section of the Ingulets river. The water for dilution comes from a storage pond in the Svystunov gully. Regulatory actions that maintain water quality without exceeding the normative values of maximum permissible discharge are determined. At the same time, water consumption for dilution is minimized. The scenario analysis of the options showed a saving of up to 30% of water resources, namely 17.5 million m3, compared to the dilution carried out in February-March 2021 according to the existing individual regulations.
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Gusev, E. M., and O. N. Nasonova. "Simulating of snow cover formation by the model of interaction between the land surface and the atmosphere (SWAP)." Ice and Snow 59, no. 2 (June 11, 2019): 167–81. http://dx.doi.org/10.15356/2076-6734-2019-2-401.
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In framework of the project «The Earth system Models – Snow Models Intercomparison Project» (ESMSnowMIP), calculations of snow storages were carried out on ten experimental sites organized for longterm monitoring of the snow cover variability in various regions of the globe. The calculation method is based on the physical and mathematical description of heat and moisture exchange processes occurring within the system «ground water – soil – vegetation cover/snow cover – surface layer of the atmosphere», and it is implemented in the form of the model of interaction between the land surface and the atmosphere (SWAP). The model was developed at the Institute of water problems (IWP) of Russian Academy of Sciences. The model makes possible to calculate components of water and heat balances and different characteristics of the hydrological regime of terrestrial ecosystems and river basins having different spatial scales and located in different natural conditions. Good quality of reproduction of the snow storages variability on all considered sites is reached that allows consideration of the SWAP model as one of the best models of the snow cover formation. Thus, the SWAP model has a sufficiently optimal degree of complexity of the algorithm for reproducing the dynamics of snow cover, which is necessary and sufficient in global and regional hydrological models describing formation of the water balance of the land in the cold regions of the planet, and can be used to create scenario forecasts of snow dynamics (as the important part of the cryosphere). This conclusion is verified by the results of using the SWAP model to reproduce long-term variability of snow storages in basins of the River Lena and the River Ob (with its tributary Irtysh) which are the two largest rivers of the Russian Federation. The calculated and measured characteristics of snow cover dynamics for these basins are shown to be in good agreement.
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Kleinhans, Maarten G., Maarten van der Vegt, Jasper Leuven, Lisanne Braat, Henk Markies, Arjan Simmelink, Chris Roosendaal, Arjan van Eijk, Paul Vrijbergen, and Marcel van Maarseveen. "Turning the tide: comparison of tidal flow by periodic sea level fluctuation and by periodic bed tilting in scaled landscape experiments of estuaries." Earth Surface Dynamics 5, no. 4 (November 28, 2017): 731–56. http://dx.doi.org/10.5194/esurf-5-731-2017.
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Abstract. Analogue models or scale experiments of estuaries and short tidal basins are notoriously difficult to create in the laboratory because of the difficulty to obtain currents strong enough to transport sand. Our recently discovered method to drive tidal currents by periodically tilting the entire flume leads to intense sediment transport in both the ebb and flood phase, causing dynamic channel and shoal patterns. However, it remains unclear whether tilting produces periodic flows with characteristic tidal properties that are sufficiently similar to those in nature for the purpose of landscape experiments. Moreover, it is not well understood why the flows driven by periodic sea level fluctuation, as in nature, are not sufficient for morphodynamic experiments. Here we compare for the first time the tidal currents driven by sea level fluctuations and by tilting. Experiments were run in a 20 × 3 m straight flume, the Metronome, for a range of tilting periods and with one or two boundaries open at constant head with free inflow and outflow. Also, experiments were run with flow driven by periodic sea level fluctuations. We recorded surface flow velocity along the flume with particle imaging velocimetry and measured water levels along the flume. We compared the results to a one-dimensional model with shallow flow equations for a rough bed, which was tested on the experiments and applied to a range of length scales bridging small experiments and large estuaries. We found that the Reynolds method results in negligible flows along the flume except for the first few metres, whereas flume tilting results in nearly uniform reversing flow velocities along the entire flume that are strong enough to move sand. Furthermore, tidal excursion length relative to basin length and the dominance of friction over inertia is similar in tidal experiments and reality. The sediment mobility converges between the Reynolds method and tilting for flumes hundreds of metres long, which is impractical. Smaller flumes of a few metres in length, on the other hand, are much more dominated by friction than natural systems, meaning that sediment suspension would be impossible in the resulting laminar flow on tidal flats. Where the Reynolds method is limited by small sediment mobility and high tidal range relative to water depth, the tilting method allows for independent control over the variables flow depth, velocity, sediment mobility, tidal period and excursion length, and tidal asymmetry. A periodically tilting flume thus opens up the possibility of systematic biogeomorphological experimentation with self-formed estuaries.
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Sultana, Mariam, Fareeha Sami Khan, M. Khalid, Areej A. Al-moneef, Ali Hasan Ali, and Omar Bazighifan. "Comparison of Predator-Prey Model and Hawk-Dove Game for Modelling Leukemia." Computational Intelligence and Neuroscience 2022 (September 22, 2022): 1–11. http://dx.doi.org/10.1155/2022/9957514.
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Game theory is an excellent mathematical tool to describe the interaction between the immune system and cancerous leukocytes c . l e u . The feature of cancerous leukocytes to differentiate and mutate to give rise to leukemia is in the domain of ecological models as well. In this work, the dynamic of leukemia is described and compared by two models: firstly by a simple probabilistic mathematical model using the zero-sum two player game of Hawk and Dove, and secondly by Leslie Predator Prey model of ecology. The main goal of this study is to compare the results of both models and then discuss the treatment of leukemia i.e., Hematopoietic Stem cell transplant with the best model among them. Hawk and Dove model also describes the cell to cell interaction of cancerous leukocytes and healthy leukocytes l e u after diagnoses and the condition of the patient before and after treatments. In this work, Hematopoietic Stem cell transplant is discussed by using concepts of a zero-sum three player game. Also, both models will be characterized by determining the stability properties, identifying basins of attraction, and locating the equilibrium points to see, at what extent the patient’s survival is possible with leukemia in its body. Results for both models will be presented graphically.
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Chentnik, Brenton M., Cari L. Johnson, Julia S. Mulhern, and Lisa Stright. "Valleys, Estuaries, and Lagoons: Paleoenvironments and Regressive–Transgressive Architecture of the Upper Cretaceous Straight Cliffs Formation, Utah, U.S.A." Journal of Sedimentary Research 85, no. 10 (October 1, 2015): 1166–96. http://dx.doi.org/10.2110/jsr.2015.70.
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Abstract: The John Henry Member of the Upper Cretaceous Straight Cliffs Formation preserves deposition of four regressive–transgressive (R-T) cycles in 350 m of strata of the Sevier foredeep in south-central Utah, USA. Each cycle is discussed in detail, with emphasis on the transgressive phases of deposition. Regressive intervals comprise wave-dominated shorefaces and coastal-plain strata, whereas transgressive intervals record tide-influenced coastal-margin and low-energy-bay and lagoonal deposits. One R-T cycle in the lower John Henry Member preserves a compound incised-valley system filled with a complex assemblage of tidal and estuarine facies. In contrast, overlying R-T cycles are not associated with valley formation, but instead preserve sandstone-rich back-barrier platform deposits that transition landward into tidal-creek, tidal-flat, and marsh depositional settings. Excellent outcrop expression permits detailed examination of the complex internal architecture of the compound incised-valley, and demonstrates that: 1) tidal ravinement significantly modified the initial valley shape during transgression, a process not fully recognized in most conceptual models of valley formation and fill; 2) the valley system incised in a basin-axial position (NNE–SSW), subparallel to the thrust front and oblique to the orientation of pre-valley-formation shorefaces, which prograded from west to east. Axial systems are well-known transporters of large volumes of sediment in foreland basins, and yet most incised-valley models imply a direct and oversimplified relationship between up-dip (source area and tectonics) and down-dip (base level) controls; 3) the major subaerial unconformity and bypass surface occurred at a higher (younger) stratigraphic position than previously interpreted, and is herein renamed the lower John Henry Member sequence boundary. The changes in regional correlations necessitated by this discovery have several broader implications for sequence stratigraphic models; 4) finally, correlations down dip along the axial valley system indicate a steep topographic gradient of 0.011, with 47% vertical, compacted expansion of the whole John Henry Member over 14 km from south to the north. This suggests structural control on sediment transport and deposition, with significant lateral variability in accommodation parallel to the fold-thrust belt. This study adds to the growing body of literature documenting the complex nature of transgressive deposits, which will aid in the interpretation, prediction, and management of analogous subsurface reservoirs.
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Orlob, G. T., A. E. Bale, H. Rajbhandari, and M. Malagoli. "Modeling Effects of Tidal Barrier Closure of Venice Lagoon." Water Science and Technology 24, no. 6 (September 1, 1991): 149–55. http://dx.doi.org/10.2166/wst.1991.0151.
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As a combined result of land subsidence and sea level rise in the vicinity of the City of Venice there has been a net decrease in the difference between the mean elevations of land and sea of about 30 centimetres over the past century. This has resulted in an increased incidence of flooding in Venice with occasional disastrous consequences, as in November 1966 when storm and tide conditions combined to flood the Piazza San Marco to depths exceeding one metre. Among the solutions proposed to solve the flooding problem is a modular tidal barrier that is designed to close the three major entrances to the shallow lagoon in which Venice is situated. Because the lagoon is highly eutrophic and circulation is driven primarily by the tide in the Adriatic Sea, there is concern that operation of the barriers could exacerbate an already serious problem of pollution. The lagoon currently receives the untreated waste water from Venice with an organic loading equivalent to more than 400,000 persons during the tourist season, industrial discharges from the Port of Marghera, and non-point accretions of nutrients from adjacent agricultural areas. Preliminary investigation of the effects of the proposed barrier scheme using mathematical hydrodynamic and water quality models suggests that prolonged isolation of the lagoon from the sea, if this should become necessary for flood protection, may enhance primary production and induce unfavorable water quality conditions. This paper presents results of this investigation and offers suggestions for further refinement and application of the models to assist in the environmental impact assessment which must be performed prior to barrier construction.
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Villena-Martínez, Esteban Manuel, Paola Andrea Alvizuri-Tintaya, Jaime Lora-Garcia, Juan Ignacio Torregrosa-López, and Vanesa Gladys Lo-Iacono-Ferreira. "A Comparative Analysis of Statistical Models and Mathematics in Reverse Osmosis Evaluation Processes as a Search Path to Achieve Better Efficiency." Water 14, no. 16 (August 12, 2022): 2485. http://dx.doi.org/10.3390/w14162485.
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An effective alternative for water purification is reverse osmosis (RO). Laboratory-scale RO modeling is widely applied worldwide, and allows the evaluation of the behavior of the system to find the most convenient operating variables to be applied in future industrial scale-ups. Statistical models provide a wide range of information that allows a statistical prediction of the operation of the plant, and allows us to obtain efficiency indices in its development; these are useful in the planning, operation and monitoring process in RO plants. The mathematical models describe the physical behavior of the membrane and allow the identification of optimal operating conditions, taking into account economic aspects, guaranteeing a greater implementation of RO technology in developing countries which have problems with water contaminated with toxic heavy metals. The present work shows a review of different statistical and mathematical models, and the suitability of these in the analysis of RO in the separation of heavy metals in drinking water that can be applied in countries with serious environmental problems. Bolivia and several river basins, such as the Guadalquivir and Milluni, present this type of problem. A comparative method is proposed to establish the advantages and selection criteria to apply the different models in RO.
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Osadchaya, L. I., and L. A. Nichkova. "CONSTRUCTIVE-GEOGRAPHICAL APPROACH IN THE MANAGEMENT OF THE IMPACT OF THE DISCHARGE OF WATER FROM STORAGE PONDS TO THE LIMITS OF RIVER BASINS." Construction economic and environmental management 79, no. 2 (2022): 17–26. http://dx.doi.org/10.37279/2519-4453-2021-2-17-26.
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The article is devoted to the development of a constructive and geographical approach to regulating the impact of the discharge of water from storage ponds within river basins with reference to the real situation of a particular large watercourse. It is established that the solution of the problem of minimizing the influence of the storage pond within the natural geographical stage is possible by optimizing the functioning of the natural-man-made system «mine-storage pond-natural watercourses». The management of the functioning of this system involves the regulation of the volume of discharge of highly mineralized water in accordance with the hydrological and hydrochemical features of natural watercourses. The optimization problem is solved by: creating a specialized bank of hydroecological data; developing an expert system of normative indicators, taking into account the criteria for their evaluation; constructing optimization mathematical models to describe the main laws of the functioning of the system under consideration. These structures are combined into a generalized information and expert system for assessing the impact of storage pond waters on the state of surface waters of river basins
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Stiefvater, T., and K. R. Muller. "A finite-size scaling investigation for Q-state Hopfield models: storage capacity and basins of attraction." Journal of Physics A: Mathematical and General 25, no. 22 (November 21, 1992): 5919–29. http://dx.doi.org/10.1088/0305-4470/25/22/019.
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Zotov, L. "Dynamical Modeling and Excitation Reconstruction as Fundamental of Earth Rotation Prediction." Artificial Satellites 45, no. 2 (January 1, 2010): 95–106. http://dx.doi.org/10.2478/v10018-010-0010-y.
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Dynamical Modeling and Excitation Reconstruction as Fundamental of Earth Rotation Prediction Though pure mathematical approximations such as regression models and neural networks show good results in Earth rotation forecasting, dynamical modeling remains the only base for the physically meaningful prediction. That assumes the knowledge of cause-effect relationships and physical model of the rotating Earth. Excitation reconstruction from the observed Earth orientation parameters (EOP) is a crucial stage, needed for comparison with known causes, such as tidal forcing, atmospheric (AAM), oceanic (OAM) angular momentum changes, and uncovering unknown ones. We demonstrate different approaches, which can be used to avoid ill-conditionality and amplification of noises during the inversion. We present amplitude and phase studies of the model and reconstructed excitations of Chandler wobble. We found out, that modulation of Chandler excitation is synchronous with 18-yr tidal effects in the Earth's rotation rate changes. The results of the study can be used for excitation and EOP forecast. The key issues of the EOP prediction are discussed.
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Tiago Damas, MARTINS, VIEIRA Bianca Carvalho, FERNANDES Nelson Ferreira, OKAFIORI Chisato, and MONTGOMERY David R. "Application of the SHALSTAB model for the identification of areas susceptible to landslides: Brazilian case studies." Revista de Geomorfologie 19, no. 1 (December 30, 2017): 136–44. http://dx.doi.org/10.21094/rg.2017.015.
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Since the 1960s, catastrophic and generalized events of hazardous mass movements caused millions of dollars in economic losses and resulted in thousands of fatalities and homelessness in Brazil. To understand these processes and attempt to predict them, mathematical models have been utilized world-wide describing the physics of the process through mathematical equations. The objective of this study was to present two areas widely affected by shallow landslides where the SHALSTAB model was applied to understand the process and to predict potentially unstable areas in several hydrographic basins. Simulations utilized the types of distinct data that were available in each area. From both areas, geotechnical data collected in the field, topographical data from digital topographical maps and Digital Terrain Models (DTM) from Light Detection and Ranging (LiDAR) were utilized. Susceptibility maps were validated using two indexes, scar concentration (SC) and landslide potential (LP), based on landslides that occurred in 1985 and 2011. Both indexes showed satisfactory results given that the unconditionally unstable category described more than 45% of the landslide events, and the LP index displayed the highest values for the most unstable categories.
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Tarantini, Francesco, Ilaria Milesi, Xabier Murgia, Federico Bianco, and Raffaele L. Dellacà. "A Compartment-Based Mathematical Model for Studying Convective Aerosol Transport in Newborns Receiving Nebulized Drugs during Noninvasive Respiratory Support." Pharmaceutics 12, no. 10 (September 30, 2020): 936. http://dx.doi.org/10.3390/pharmaceutics12100936.
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Nebulization could be a valuable solution to administer drugs to neonates receiving noninvasive respiratory support. Small and irregular tidal volumes and air leaks at the patient interface, which are specific characteristics of this patient population and are primarily responsible for the low doses delivered to the lung (DDL) found in this application, have not been thoroughly addressed in in vitro and in vivo studies for quantifying DDL. Therefore, we propose a compartment-based mathematical model able to describe convective aerosol transport mechanisms to complement the existing deposition models. Our model encompasses a mechanical ventilator, a nebulizer, and the patient; the model considers the gas flowing between compartments, including air leaks at the patient–ventilator interface. Aerosol particles are suspended in the gas flow and homogeneously distributed. The impact of breathing pattern variability, volume of the nebulizer, and leaks level on DDL is assessed in representative conditions. The main finding of this study is that convective mechanisms associated to air leaks and breathing patterns with tidal volumes smaller than the nebulizer dramatically reduce the DDL (up to 70%). This study provides a possible explanation to the inconsistent results of drug aerosolization in clinical studies and may provide guidance to improve nebulizer design and clinical procedures.
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HRISSANTHOU, V., and A. PSILOVIKOS. "Distributed modeling of soil erosion and sediment transport." Bulletin of the Geological Society of Greece 34, no. 2 (August 1, 2018): 763. http://dx.doi.org/10.12681/bgsg.17354.
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A mathematical model is used for the estimation of the annual sediment yield resulting from rainfall and runoff at the outlet of Nestos River basin (Toxotes, Thrace, Greece), where the ecologically interesting Nestos delta exists. The model is applied to that part of Nestos River basin (838 km2) which lies downstream of three dams. Two dams (Thissavros and Platanovryssi) have been already constructed, while the third one (Temenos) is under construction. The model consists of three sub-models: a rainfall-runoff sub-model, a surface erosion sub-model and a sediment transport sub-model for streams. This model is also capable of computing the annual erosion amount and sediment yield in the individual sub-basins
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Li, Zhuang, Zhilin Long, Shan Lei, Xiaowei Liu, Lingming Yang, Wei Zhang, and Ting Zhang. "Evaluating the corrosion resistance of marine steels under different exposure environments via machine learning." Physica Scripta 98, no. 1 (December 2, 2022): 015402. http://dx.doi.org/10.1088/1402-4896/aca43a.
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Abstract The corrosion behavior of marine engineering steels in marine environment is an extremely complex process, which poses great challenge to accurately evaluate the corrosion resistance of various stees in different marine environment. Owing to the wide application of machine learning (ML) approaches and the accumulation of corrosion data of different steels in natural marine environment, herein, we reported eXtreme Gradient Boosting (XGBoost) ML models for predicting the corrosion rate in submerged, tidal and splash zones. By taking material composition, environmental factors and exposure time as inputs, the developed prediction models can well predict the corrosion rate with the accuracy of 93%, 96% and 93% for submerged, tidal and splash zones, respectively. In addition, we identified the key factors affecting the corrosion resistance of steels in different marine zones, and analyzed the relationship between these factors and corrosion rate by applying SHapley Additive exPlanations (SHAP) method. This work demonstrates that ML model combined with SHAP method are efficient in evaluating corrosion behavior of various steels in different marine environment.
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Roberts, W., P. Le Hir, and R. J. S. Whitehouse. "Investigation using simple mathematical models of the effect of tidal currents and waves on the profile shape of intertidal mudflats." Continental Shelf Research 20, no. 10-11 (July 2000): 1079–97. http://dx.doi.org/10.1016/s0278-4343(00)00013-3.
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Zemel, Richard S., and Michael C. Mozer. "Localist Attractor Networks." Neural Computation 13, no. 5 (May 1, 2001): 1045–64. http://dx.doi.org/10.1162/08997660151134325.
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Attractor networks, which map an input space to a discrete output space, are useful for pattern completion—cleaning up noisy or missing input features. However, designing a net to have a given set of attractors is notoriously tricky; training procedures are CPU intensive and often produce spurious attractors and ill-conditioned attractor basins. These difficulties occur because each connection in the network participates in the encoding of multiple attractors. We describe an alternative formulation of attractor networks in which the encoding of knowledge is local, not distributed. Although localist attractor networks have similar dynamics to their distributed counterparts, they are much easier to work with and interpret. We propose a statistical formulation of localist attractor net dynamics, which yields a convergence proof and a mathematical interpretation of model parameters. We present simulation experiments that explore the behavior of localist attractor networks, showing that they yield few spurious attractors, and they readily exhibit two desirable properties of psychological and neurobiological models: priming (faster convergence to an attractor if the attractor has been recently visited) and gang effects (in which the presence of an attractor enhances the attractor basins of neighboring attractors).
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Zhang, H., G. D. Egbert, A. D. Chave, Q. Huang, A. Kelbert, and S. Y. Erofeeva. "Constraints on the resistivity of the oceanic lithosphere and asthenosphere from seafloor ocean tidal electromagnetic measurements." Geophysical Journal International 219, no. 1 (July 11, 2019): 464–78. http://dx.doi.org/10.1093/gji/ggz315.
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SUMMARY The electromagnetic (EM) field generated by ocean tidal flow is readily detectable in both satellite magnetic field data, and in ocean-bottom measurements of electric and magnetic fields. The availability of accurate charts of tidal currents, constrained by assimilation of modern satellite altimetry data, opens the possibility of using tidal EM fields as a source to image mantle electrical resistivity beneath the ocean basins, as highlighted by the recent success in defining the globally averaged lithosphere–asthenosphere boundary (LAB) with satellite data. In fact, seafloor EM data would be expected to provide better constraints on the structure of resistive oceanic lithosphere, since the toroidal magnetic mode, which can constrain resistive features, is a significant component of the tidal EM field within the ocean, but is absent above the surface (in particular in satellite data). Here we consider this issue in more detail, using a combination of simplified theoretical analysis and 1-D and 3-D numerical modelling to provide a thorough discussion of the sensitivity of satellite and seafloor data to subsurface electrical structure. As part of this effort, and as a step toward 3-D inversion of seafloor tidal data, we have developed a new flexible 3-D spherical-coordinate finite difference scheme for both global and regional scale modelling, with higher resolution models nested in larger scale solutions. We use the new 3-D model, together with Monte Carlo simulations of errors in tidal current estimates, to provide a quantitative assessment of errors in the computed tidal EM signal caused by uncertainty in the tidal source. Over the open ocean this component of error is below 0.01 nT in Bz at satellite height and 0.05 nT in Bx on the seafloor, well below typical signal levels. However, as coastlines are approached error levels can increase substantially. Both analytical and 3-D modelling demonstrate that the seafloor magnetic field is most sensitive to the lithospheric resistance (the product of resistivity and thickness), and is more weakly influenced (primarily in the phase) by resistivity of the underlying asthenosphere. Satellite data, which contain only the poloidal magnetic mode, are more sensitive to the conductive asthenosphere, but have little sensitivity to lithospheric resistance. For both seafloor and satellite data’s changes due to plausible variations in Earth parameters are well above error levels associated with source uncertainty, at least in the ocean interior. Although the 3-D modelling results are qualitatively consistent with theoretical analysis, the presence of coastlines and bathymetric variations generates a complex response, confirming that quantitative interpretation of ocean tidal EM fields will require a 3-D treatment. As an illustration of the nested 3-D scheme, seafloor data at five magnetic and seven electric stations in the northeastern Pacific (41○N, 165○W) are fit with trial-and-error forward modelling of a local domain. The simulation results indicate that the lithospheric resistance is roughly 7 × 108 Ωm2. The phase of the seafloor data in this region are inconsistent with a sharp transition between the resistive lithosphere and conductive asthenosphere.
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Li, Tilai, Xiangyu Gao, Xinzhou Zhang, and Yinshuang Wang. "IMPACT OF RUNOFF ON SALT INTRUSION OF YANGTZE ESTUARY." Coastal Engineering Proceedings 1, no. 32 (February 2, 2011): 49. http://dx.doi.org/10.9753/icce.v32.management.49.
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Based on one-dimensional and two-dimensional mathematical coupling models of tidal current and salinity from Datong to Yangtze estuary, the impacting scope of salt intrusion are calculated when the runoff of Datong from 4,500m3/s to 30,000m3/s, and the maximum and average value of salinity at each representative point of the estuary are given. When flow of Datong is less than 10,000 m3/s, if projects of water transfer, pumping and diversion are not taken into account at the lower reaches of Datong, the maximum salinity at the downstream reaches of Xuliujing and the average salinity at the downstream reaches of Baimaosha will exceed drinking water criteria.
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Yan, Bao-Wei, Yi-Xuan Zou, Yu Liu, Ran Mu, Hao Wang, and Yi-Wei Tang. "Addressing Spatial Heterogeneity in the Discrete Generalized Nash Model for Flood Routing." Water 13, no. 21 (November 7, 2021): 3133. http://dx.doi.org/10.3390/w13213133.
Full textAbstract:
River flood routing is one of the key components of hydrologic modeling and the topographic heterogeneity of rivers has great effects on it. It is beneficial to take into consideration such spatial heterogeneity, especially for hydrologic routing models. The discrete generalized Nash model (DGNM) based on the Nash cascade model has the potential to address spatial heterogeneity by replacing the equal linear reservoirs into unequal ones. However, it seems impossible to obtain the solution of this complex high order differential equation directly. Alternatively, the strict mathematical derivation is combined with the deeper conceptual interpretation of the DGNM to obtain the heterogeneous DGNM (HDGNM). In this work, the HDGNM is explicitly expressed as a linear combination of the inflows and outflows, whose weight coefficients are calculated by the heterogeneous S curve. Parameters in HDGNM can be obtained in two different ways: optimization by intelligent algorithm or estimation based on physical characteristics, thus available to perform well in both gauged and ungauged basins. The HDGNM expands the application scope, and becomes more applicable, especially in river reaches where the river slopes and cross-sections change greatly. Moreover, most traditional routing models are lumped, whereas the HDGNM can be developed to be semidistributed. The middle Hanjiang River in China is selected as a case study to test the model performance. The results show that the HDGNM outperforms the DGNM in terms of model efficiency and smaller relative errors and can be used also for ungauged basins.
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DEL POPOLO, ANTONINO. "IMPROVEMENTS TO THE SPHERICAL COLLAPSE MODEL." International Journal of Modern Physics D 15, no. 07 (July 2006): 1067–88. http://dx.doi.org/10.1142/s0218271806008553.
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We study the joint effect of dynamical friction, tidal torques and cosmological constant on clusters of galaxy formation. We show that within high-density environments, such as rich clusters of galaxies, both dynamical friction and tidal torques slow down the collapse of low-ν peaks producing an observable variation in the time of collapse of the perturbation and, as a consequence, a reduction in the mass bound to the collapsed perturbation. Moreover, the delay of the collapse produces a tendency for less dense regions to accrete less mass, with respect to a classical spherical model, inducing a biasing of over-dense regions toward higher mass. We show how the threshold of collapse is modified if dynamical friction, tidal torques and a non-zero cosmological constant are taken into account and we use the Extended Press–Schecter (EPS) approach to calculate the effects on the mass function. Then, we compare the numerical mass function given in D. Reed, Mon. Not. R. Astron. Soc.346, 565 (2003) with the theoretical mass function obtained in the present paper. We show that the barrier obtained in the present paper gives rise to a better description of the mass function evolution with respect to other previous models, R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.308, 119 (1999) and R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.329, 61 (2002).