Development of a New 8-Parameter Muskingum Flood Routing Model with Modified Inflows

Flood routing can be subclassified into hydraulic and hydrologic flood routing; the former yields accurate values but requires a large amount of data and complex calculations. The latter, in contrast, requires only inflow and outflow data, and has a simpler calculation process than the hydraulic one. The Muskingum model is a representative hydrologic flood routing model, and various versions of Muskingum flood routing models have been studied. The new Muskingum flood routing model considers inflows at previous and next time during the calculation of the inflow and storage. The self-adaptive vision correction algorithm is used to calculate the parameters of the proposed model. The new model leads to a smaller error compared to the existing Muskingum flood routing models in various flood data. The sum of squares obtained by applying the new model to Wilson’s flood data, Wang’s flood data, the flood data of River Wye from December 1960, Sutculer flood data, and the flood data of River Wyre from October 1982 were 4.11, 759.79, 18,816.99, 217.73, 38.81 (m3/s)2, respectively. The magnitude of error for different types of flood data may be different, but the error may be large if the flow rate of the flood data is large.

Addressing Spatial Heterogeneity in the Discrete Generalized Nash Model for Flood Routing

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.

Consideration of Docker based network deployment for a data center: GSDC in Korea

For various operational reasons, this study presents a design and testbed environment for applying Docker-based system to a data center in Korea. We describe the design process of Docker based network. First, abstract structure is presented. Second, two conceptual routing models are provided. Third, the network plugin selection is stated. Then, we build Docker based system on a testbed environment as a pre-study for deployment to the entire system. There are plenty of factors to consider for the overall deployment. Representative factors include the routing method inside the server, the number of containers in a server, service arrangement by container, and response to equipment replacement. To evaluate those factors, various study should be performed with key system parameters. The proposed testbed environment can be utilized to obtain key system parameters. Applying Docker system to a data center can be remarkably efficient in terms of operations. The workload of operator will decrease, and scalability and flexibility will increase.

Quantitative Sediment Storage Chronology Associated with European Colonization of the Mid-Atlantic U.S. and its Application to Watershed Scale Sediment Routing

<p>As sediment is carried through watersheds, it may be stored in floodplains and other alluvial deposits, remaining in place for hundreds to millions of years before being remobilized and transported farther downstream.  Sediment routing models based on reservoir theory can account for time-varying sediment storage and predict lags in sediment delivery imposed by sediment storage, but observational data are needed to construct and validate these models.  Because of the long timescales involved, direct observations are rarely useful, but stratigraphic observations coupled with sediment dating techniques can be used to quantify the amount of sediment stored through time and its associated age and storage (or transit) time distributions. To illustrate this approach, a meta-analysis of published geologic data is used to quantify river corridor storage through time associated with European colonization of the mid-Atlantic U.S.  The history of floodplain growth from Holocene to the present is summarized by empirical distributions extracted from stratigraphic data; distributions were sampled to create thousands of synthetic age-depth curves.  Deposits predating European colonization range in age from >18,000 yrs. to 225 yrs. B.P. and with a median thickness of 40% of the total accumulation; sedimentation rates for these deposits are low (median = 0.06 cm/yr).  The median thickness of sediments deposited between 1750 and 1900 (“legacy sediments”) comprises 36% of the total; the median accumulation rate of legacy sediments is 0.32 cm/yr.  The median thickness of sediments deposited after 1950 represents 11% of total accumulation, and the median contemporary sedimentation rate of 0.26 cm/yr is statistically indistinguishable from that of legacy sediments.  Synthetic vertical sequences can be recast as age distributions, and when combined with geomorphic mapping and assessment of patterns of erosion through time, as storage time distributions as well.  Age and storage time distributions at 1000 yrs. B.P., in 1900 A.D., and at present are highly variable, and could be represented by many different mathematical functions, though averaged data appear to be heavy-tailed.   Records of mass accumulation through time and the present and past age and storage time distributions provide useful summaries of the history of sediment storage, and can be used to calibrate and verify watershed scale sediment routing models over millennial timescales.</p>

Intercomparison of surface meltwater routing models for the Greenland ice sheet and influence on subglacial effective pressures

Each summer, large volumes of surface meltwater drain off the Greenland ice sheet (GrIS) surface through moulins to the bed, impacting subglacial hydrology and ice flow dynamics. Supraglacial surface routing delays may propagate to englacial and subglacial hydrologic systems, requiring accurate assessment to correctly estimate subglacial effective pressures. We compare hourly supraglacial moulin discharge simulations from three surface meltwater routing models – the synthetic unit hydrograph (SUH), the bare-ice component of surface routing and lake filling (SRLF), and the rescaled width function (RWF) – for four internally drained catchments on the southwestern Greenland ice sheet surface. The routing models are forced identically using surface runoff from the Modèle Atmosphérique Régionale regional climate model (RCM). For each catchment, simulated moulin hydrographs are input to the SHAKTI subglacial hydrologic model to simulate diurnally varying subglacial effective-pressure variations in the vicinity of a single moulin. Overall, all three routing models produce more realistic moulin discharges than simply using RCM runoff outputs without surface routing but produce significant differences in peak moulin discharge and time to peak. In particular, the RWF yields later, smaller peak moulin discharges than the SUH or SRLF due to its representation of slow interfluve flow between supraglacial meltwater channels, and it can readily accommodate the seasonal evolution of supraglacial stream and river networks. Differences among the three routing models are reflected in a series of simple idealized subglacial hydrology simulations that yield different diurnal effective-pressure amplitudes; however, the supraglacial hydrologic system acts as short-term storage for surface meltwater, and the temporal mean effective pressure is relatively consistent across routing models.

Review and Analysis of Energy-Efficient Routing in Wireless Sensor Networks

This review paper focuses on different studies that have examined this subject involving the development and implementation of different energy-efficient routing protocols. Specifically, the paper seeks to unearth issues such as the methodologies adopted, the proposed energy-efficient routing models in different scenarios and applications, and the scholars’ results regarding the impact of the proposed algorithms on the network lifetime of WSNs. From the results, a common trend and emerging theme that have been established demonstrate that when energy-efficient routing systems are implemented, they are likely to minimize the energy consumption of WSN networks. With energy consumption minimized, the resultant efficiency with which the energy-efficient routing protocols are associated contributes to an increase in the network lifetime.