Linear Routing Research Articles

Performance improvement of the linear muskingum flood routing model using optimization algorithms and data assimilation approaches

Performance improvement of the linear muskingum flood routing model using optimization algorithms and data assimilation approaches

Spline approximation of multivalued functions in linear structures routing

Objectives. The theory and methods of spline approximation of plane curves given by a sequence of points are currently undergoing rapid development. Despite fundamental differences between used splines and those considered in the theory and its applications, results published earlier demonstrate the possibility of using spline approximation when designing routes of linear structures. The main difference here consists in the impossibility of assuming in advance the number of spline elements when designing the routes. Here, in contrast to widely use polynomial splines, the repeating element is the link “segment of a straight line + arc of a circle” or “segment of a straight line + arc of a clothoid + arc of a circle + arc of a clothoid.” Previously, a two-stage scheme consisting of a determination of the number of elements of the desired spline and subsequent optimization of its parameters was proposed. Although an algorithm for solving the problem in relation to the design of a longitudinal profile has been implemented and published, this is not suitable for designing a route plan, since, unlike a profile, a route plan is generally a multivalued function. The present paper aims to generalize the algorithm for the case of spline approximation of multivalued functions making allowance for the design features of the routes of linear structures.Methods. At the first stage, a novel mathematical model is developed to apply the dynamic programming method taking into account the constraints on the desired spline parameters. At the second stage, nonlinear programming is used. In this case, it is possible to analytically calculate the derivatives of the objective function with respect to the spline parameters in the absence of its analytical expression through these parameters.Results. An algorithm developed for approximating multivalued functions given by a discrete series of points using a spline consisting of arcs of circles conjugated by line segments for solving the first stage of the problem is presented. An additional nonlinear programming algorithm was also used to optimize the parameters of the resulting spline as an initial approximation. However, in the present paper, the first stage is considered only, since the complex algorithm of the second stage and its justification require separate consideration.Conclusions. The presented two-stage spline approximation scheme with an unknown number of spline elements is also suitable for approximating multivalued functions given by a sequence of points on a plane, in particular, for designing a route plan for linear structures.

Cyber‐physical network architecture for data stream provisioning in complex ecosystems

AbstractIntelligent fog cyber‐physical social systems (iFog CPSS) is a novel smart city project that uses intrinsic processes to automate microservices such as edge‐to‐fog or fog‐to‐cloud monitoring of complex real‐time activities. This article presents a dynamic cyber‐physical architecture that leverages iFog layers to map location‐based services (LBS) on a spine‐leaf datacenter clos topology. Individual edge clusters are connected to the edge‐fog layer, which communicates with iFog gateways for processing streams' requests. Use‐case application of artificial intelligence (AI) in vehicular ad‐hoc networks (VANETs) is introduced for data stream provisioning. In the validation study, a secure docker‐based iFog CPS experiment is carried out using traffic trace files from C++ modeller. iFog spine‐leaf architecture for fog‐computing and cloud‐computing are compared using two key metrics. For traffic workload utilization, the results show that 83.33% of the traffic workload is utilized at the Fog layer while 16.67% is consumed in the cloud layer. For latency profile, the results indicate that Fog and cloud streams had 20.31% and 77.69%, respectively. In terms of iFog VANET spine‐leaf congestion control, three distinct algorithms are studied, namely the proposed linear routing algorithm (LRA), LEACH, and collection tree protocol (CTP). In each case, the resource utilization for VANET gave 34.45%, 32.18%, and 33.37%, respectively. Latency response gave 11.76%, 82.35%, and 5.89%, respectively. Also, the throughput scenario offered 19.61%, 39.22%, and 41.17%, respectively. Consequently, the iFog scenario offers satisfactory LBS provisioning for VANETs clusters.

Two-stage spline-approximation in linear structure routing

In the article, computer design of routes of linear structures is considered as a spline approximation problem. A fundamental feature of the corresponding design tasks is that the plan and longitudinal profile of the route consist of elements of a given type. Depending on the type of linear structure, line segments, arcs of circles, parabolas of the second degree, clothoids, etc. are used. In any case, the design result is a curve consisting of the required sequence of elements of a given type. At the points of conjugation, the elements have a common tangent, and in the most difficult case, a common curvature. Such curves are usually called splines. In contrast to other applications of splines in the design of routes of linear structures, it is necessary to take into account numerous restrictions on the parameters of spline elements arising from the need to comply with technical standards in order to ensure the normal operation of the future structure. Technical constraints are formalized as a system of inequalities. The main distinguishing feature of the considered design problems is that the number of elements of the required spline is usually unknown and must be determined in the process of solving the problem. This circumstance fundamentally complicates the problem and does not allow using mathematical models and nonlinear programming algorithms to solve it, since the dimension of the problem is unknown. The article proposes a two-stage scheme for spline approximation of a plane curve. The curve is given by a sequence of points, and the number of spline elements is unknown. At the first stage, the number of spline elements and an approximate solution to the approximation problem are determined. The method of dynamic programming with minimization of the sum of squares of deviations at the initial points is used. At the second stage, the parameters of the spline element are optimized. The algorithms of nonlinear programming are used. They were developed taking into account the peculiarities of the system of constraints. Moreover, at each iteration of the optimization process for the corresponding set of active constraints, a basis is constructed in the null space of the constraint matrix and in the subspace – its complement. This makes it possible to find the direction of descent and solve the problem of excluding constraints from the active set without solving systems of linear equations. As an objective function, along with the traditionally used sum of squares of the deviations of the initial points from the spline, the article proposes other functions taking into account the specificity of a particular project task.

Copula-based modeling of hydraulic structures using a nonlinear reservoir model

Abstract Multivariate flood frequency analysis has been widely used in the design and risk assessment of hydraulic structures. However, analytical solutions are often obtained based on an idealized linear reservoir model in which a linear routing process is assumed, and consequently, the flood risk is likely to be over- or underestimated. The present study proposes a nonlinear reservoir model in which the relationships of reservoir water level with reservoir volume and discharge are assumed to be nonlinear in order to more accurately describe the routing process as it takes into consideration the interactions between hydrological loading and different discharge structures. The structure return period is calculated based on the copula function and compared with that based on the linear reservoir model and the bivariate return period based on the Kendall distribution function. The results show that the structure return period based on the linear model leads to an underestimation of the flood risk under the conditions of high reservoir water level. For the same reservoir, linear and nonlinear reservoir models give quite different reservoir volume-water level and discharge-water level curves; therefore, they differ substantially in the sensitivity to flood events with different combinations of flood peak and volume. We also analyze the effects of the parameters involved in the reservoir volume-water level and discharge-water level relationships on the maximum water level at different return periods in order to better understand the applicability and effectiveness of the proposed method for different hydraulic projects.

Channel-flow response function considering the downstream tidal effect and hydraulic characteristics

The channel impulse response function derived from the linearized Saint Venant equations has been widely applied to predict the streamflow discharge. Huang and Lee (2020) indicated that the distribution type of the impulse response function proposed by Dooge et al. (1987a) was restricted because of the constant reference parameters, therefore, they introduced the time-varying reference parameters according to the upstream inflow condition to reinforce the flexibility of adjusting the impulse response function. However, this model, called channel hydrological response function (CHARFU), was merely applicable to a channel under the assumption of a downstream open boundary. This study intended to apply the other impulse response function which was derived from the downstream disturbance and combine this function with the one derived from the upstream input to extend the model applicability in various channel states. To consider the temporal change of the downstream boundary condition, the time-varying reference parameters were also introduced in the function according to the tidal level at the estuary. A routing procedure that explained the integration of the two impulse responses for both upstream and downstream inputs was proposed as well for the runoff simulation of the entire river basin. A series of tests showed that the proposed model could even yield similar hydrographs with the comparative cases that applied the numerical model based on the Saint Venant equations owing to the revision of reference parameters. A practical case of a river basin was also provided to demonstrate the effectiveness of the proposed model to reflect the influence of the downstream tidal level on the simulated hydrograph. Although the proposed linear channel routing method still can not be applied to simulate a channel reach with flow transitions such as a sharp change of water surface elevation due to the assumption of gradually varied flow in the linearized governing equations, it can be more stable than a finite difference model and avoids the latter’s occasional numerical oscillations, especially when applied to a shallow channel with an irregular bed.

Non-linear Routing Scheme at Grid Cell Level for Large Scale Hydrologic Models: A Review

New tools and concepts in the form of mathematical models, remote sensing and Geographic Information System (GIS), communication and telemetering have been developed for the complex hydrologic systems that permit a different analysis of processes and allow watershed to be considered as an integrated planning and management unit. Hydrological characteristics can be generated through spatial analysis, and ready for input into a distributed hydrologic models to define adequately the hydrological response of a watershed that can be related back to the specific environmental, climatic, and geomorphic conditions. In the present paper, some recent development in hydrologic modeling will be reviewed with recognition of the role of horizontal routing scheme in large scale hydrologic modeling. Among others, these developments indicated the needs of alternative horizontal routing models at grid scale level that can be coupled to land surface parameterization schemes that presently still employed the linear routing model. Non-linear routing scheme will be presented and discussed in this paper as possible extension.

Surface Routing for Wireless Power Transfer Using 2-D Relay Resonator Arrays

Wireless power transfer via magnetic resonance coupling offers the prospect of autonomously charging connected devices. Previous work demonstrated that the system deployment can be facilitated by “routing” power on 2-D relay resonator arrays, using the multi-hop phenomenon. Power propagates through untethered relay resonators in such systems, and the routing strategy significantly affects the power transfer efficiency. However, most previous studies limit the routing to line-shaped routes, which compromises power transfer efficiency to preserve the simplicity of analysis. Here we show a surface routing approach, which can be orderly generated and is more efficient than linear routing. The confronting challenge is the complex representation of cross-coupled relays, which this work overcomes by conditioning the resonators’ current by appending additional loading conditions to the relays. Simulation-based evaluations show that the proposed approach improves the efficiency by up to 10% in 1.5 m range power delivery.

Channel hydrological response function considering inflow conditions and hydraulic characteristics

To bypass the problem of numerical instability in conducting the channel routing system, the application of an impulse response function based on the linearization of Saint Venant equations has been an alternative for predicting streamflow discharge. However, the distribution type of the impulse response function proposed by Dooge et al. (1987a) is restricted during a flood, so this approach cannot adequately describe flow response in practical applications. In considering that the flow response in a natural channel is usually influenced by the shape of the cross-section, the terrain of channel bed and the discharge of the moving flood, this study focuses on improving the original unit impulse function by conducting two aspects of analysis: (1) the distribution of unit impulse response function was changed with time by adjusting the reference parameters according to the inflow condition and the hydraulic variables; (2) the outcome of this modified linear approach was thoroughly examined by comparing the simulated results with that adopting the original linear channel method and the numerical scheme based on the nonlinear Saint Venant equations. Moreover, for achieving the simulation of a whole river basin, a complete executing procedure was provided to explain the connection between the upstream inflows, lateral flows, and the linear channel response of each channel reach. A series of tests showed that the proposed method can produce approximated hydrographs in comparison with numerical simulation results owing to the flexibility of the impulse response function although the linear channel routing adopts simplified mathematical operations. A case study of a natural river basin also demonstrated the applicability of the modified channel response system.

Refinement of the channel response system by considering time‐varying parameters for flood prediction

AbstractImpulse response functions derived from different types of flood wave equations (simplified shallow water equations) are continuously developed to conduct the linear channel routing (LCR), which is based on the linearized Saint Venant equation and has been widely applied to avoid any possibility of numerical instability. The impulse response function proposed by Dooge, Napiórkowski, and Strupczewski (1987) and derived from the dynamic wave equation with complete force terms has been acknowledged as a classic work to establish a good physical interpretation for the LCR model; however, the flexibility of altering the shape of impulse response still needs to be improved. Based on the concept of this work, this study intends to introduce the time‐varying parameters in the model, so the values of parameters can be adjusted according to the inflow condition, flood stage, and the cross‐sectional shape. Moreover, an integrated routing procedure is proposed to formulate the impulse response function for lateral‐flow inputs and then to connect multiple inputs from subwatersheds or alongside the main channel with the impulse response function of each channel segment to reflect the spatial variation of hydraulic characteristics among different segments. In the discussion of this article, the impulse response function is analysed to show its sensitivity to hydraulic variables with spatial and temporary variations. Flood‐event simulations of a studied watershed are also provided to verify the applicability of the proposed channel routing system.

MLPR-ASTP: Multipath Linear Propagation Routing based Improving Transmission in VANET Using Adaptive Sequence Transmission on Delay Path

MLPR-ASTP: Multipath Linear Propagation Routing based Improving Transmission in VANET Using Adaptive Sequence Transmission on Delay Path

Congruent routing protocols in diverse tree topology ZigBee built home area networks

At the residential level, the important services of smart grid namely Advanced metering infrastructure and Demand response are accomplished by the smart energy devices such as smart electrical appliances and smart meters to support dynamic price, bill, control from the utility and export of surplus power. To enhance the quality and reliability of smart grid services and power dispatch, ZigBee built smart energy home area networks are deployed as the last hop of smart grid networks to collect real-time home data. However, routing is the major issue in determining the efficacy of such networks. Moreover, ZigBee employs a tree addressing scheme that helps in assigning unique address to each node in network. This paper evokes congruent routing protocols such as ZigBee shortcut tree routing (ZSTR), ZigBee opportunistic STR, ZigBee directional OSTR, Energy Potent STR for tree topology and a Linear path cluster tree routing for long thin tree topology. Exclusively, this paper proposes a new routing named Energy potent ZigBee directional opportunistic short-cut routing and show its performances in routing, congestion management, bandwidth utilization enhancement, network lifetime expansion and power consumption reduction comparatively with other five diverse routings.

Агроекологічна ефективність ґрунтозахисних технологій у системі контурно-меліоративної організації землекористування

The purpose. To study the long-term impact of the application of the main tillage methods and fertilizer system of soil-protective crop rotation on the development of erosion-accumulation processes, flushing intensity of surface soil layer, sediment and nutrient removal, fertility indicators, erosion resistance of typical eroded chernozem, crop yields. Methods. Methods for assessing the intensity of erosion-accumulative processes, including stationary observations at runoff sites, experimental studies of the intensity of soil erosion and linear erosion, field routing, field and laboratory experiments, comparative analytical, calculation methods. Results. They present the results of the study of long-term impact of growing technologies for applying various cultivation and fertilizer methods to soil loss, nutrients as a result of erosion, runoff of surface water and sediment, productive moisture reserves in the 150 cm soil layer, humus content, and crop rotation crop yields. Conclusions. In the system of contour-reclamation organization of the land use territory, crop cultivation technologies based on long-term permanent application of non-subsurface multi-depth processing method and slitting of typical chernozem washed out on a slope of steepness of 5–6° are inherently soil-protective and provide reliable protection of soil cover from water erosion processes, improve moisture availability for plants in agrocenoses and water regime of the washed away soil, improve structural-aggregate composition and indicators of degradation fertility cationic chernozem, increase the productivity of cultures of protection crop rotation. In conditions of the high potential danger of erosion-accumulation processes, the introduction of soil-protection contour-reclamation organization of land use provides a significant reduction in degradation processes and loss of nutrients with surface runoff in sloping agro-landscapes.

Special Spline Approximation in CAD Systems of Linear Structure Routing

This article deals with the problem of approximation of plane curves defined by a sequence of points by a spline of a given type. This task arises when developing methods for computer-aided design of linear structures: railways and roads, trenches for laying pipelines, canals, etc. Its fundamental differences from the problems are considered in the theory of splines and its applications are as follows: spline elements are of various types (straight line segments and circles joined by clothoids), the boundaries of the elements and even their number is unknown; also there are restrictions - inequalities on the parameters of the elements. Continuity of the curve, the tangent, and the curvature is provided. Clothoids are missing if curvature continuity is not required, for example, when designing pipelines. The above mentioned features of the task do not allow using the achievements of the theory of splines and nonlinear programming. We cannot recognize the individual elements of the desired spline by a given sequence of points. Therefore, it is not possible to implement their selection separately. We must search for the spline as a whole. The article presents a mathematical model and a new algorithm for solving the problem using dynamic programming.

A Long–Term Response-Based Rainfall-Runoff Hydrologic Model: Case Study of The Upper Blue Nile

This study develops a response-based hydrologic model for long-term (continuous) rainfall-runoff simulations over the catchment areas of big rivers. The model overcomes the typical difficulties in estimating infiltration and evapotranspiration parameters using a modified version of the Soil Conservation Service curve number SCS-CN method. In addition, the model simulates the surface and groundwater hydrograph components using the response unit-hydrograph approach instead of using a linear reservoir routing approach for routing surface and groundwater to the basin outlet. The unit-responses are Geographic Information Systems (GIS)-pre-calculated on a semi-distributed short-term basis and applied in the simulation in every time step. The unit responses are based on the time-area technique that can better simulate the real routing behavior of the basin. The model is less sensitive to groundwater infiltration parameters since groundwater is actually controlled by the surface component and not the opposite. For that reason, the model is called the SCHydro model (Surface Controlled Hydrologic model). The model is tested on the upper Blue Nile catchment area using 28 years daily river flow data set for calibration and validation. The results show that SCHydro model can simulate the long-term transforming behavior of the upper Blue Nile basin. Our initial assessment of the model indicates that the model is a promising tool for long-term river flow simulations, especially for long-term forecasting purposes due to its stability in performing the water balance.

Address Assignment and Linear Path Cluster Tree Routing in ZigBee Built Wireless Sensor Networks

Address Assignment and Linear Path Cluster Tree Routing in ZigBee Built Wireless Sensor Networks

Multi Model Mitigation Approach for Network Threats on Cluster Based Linear Chain Routing Protocol in Wireless Sensor Networks at QoS Development

Consider the wireless sensor network (WSN) deployed in the motivation to perform data collection through the sensor nodes of the network deployed in different geographic region with same set of configuration where each can directly communicate to the base station. There are many routing protocols exists but the cluster based linear chain routing is focused towards reducing energy depletion by performing cooperative transmission to reach the destination. Because of the nodes has no mobility and the cluster formation is performed once, the linear chain routing protocol is more prone for variety of routing attacks which spoils the motivation of linear chain routing and reduce the lifetime of the network in rapid manner. We propose a multi model mitigation technique which handles variety of network threats happen in routing of packets increases the performance of WSN. This method performs flow estimation technique to identify the denial of service attacks and botnet based attacks. An light weight location verification protocol has been depicted to handle the sink hole attacks. The problem of packet dropping attack has been handled by one step verification process. The multi model mitigation techniques have produced efficient result in Quality of Service development and improve the performance of the linear chain routing.

An Investigation of Errors in Distributed Models' Stream Discharge Prediction Due to Channel Routing

AbstractOver the summer of 2015, the National Water Center hosted the National Flood Interoperability Experiment (NFIE) Summer Institute. The NFIE organizers introduced a national‐scale distributed hydrologic modeling framework that can provide flow estimates at around 2.67 million reaches within the continental United States. The framework generates discharges by coupling a given Land Surface Model (LSM) with the Routing Application for Parallel Computation of Discharge (RAPID). These discharges are then accumulated through the National Hydrography Dataset Plus stream network. The framework can utilize a variety of LSMs to provide the runoff maps to the routing component. The results obtained from this framework suggested that there still exists room for further enhancements to its performance, especially in the area of peak timing and magnitude. The goal of our study was to investigate a single source of the errors in the framework's discharge estimates, which is the routing component. The authors substitute RAPID which is based on the simplified linear Muskingum routing method by the nonlinear routing component the Iowa Flood Center have incorporated in their full hydrologic Hillslope‐Link Model. Our results show improvement in model performance across scales due to incorporating new routing methodology.

PLA Compression Schemes Assessment in Multi-hop Wireless Sensor Networks

Energy consumption is one of the most important factors to consider in the design of Wireless Sensor Networks (WSNs). Many research works have been focused on lowering the transmission of the raw data by adopting lossy compression methods in order to improve energy efficiency. In this paper, we perform a thorough energetic assessment of lossy compression scheme in multi-hop wireless sensor network. We present an evaluation of multi-hop network which adopts Piecewise Linear Approximation methods and Minimum Transmission Energy routing approach. A comparative analysis aims to evaluate the performance of the performed configuration in terms of energy consumption using real-world sensor datasets.

Robust routing and timetabling in complex railway stations

In nearly saturated station areas the limited capacity is one of the main reasons of delay propagation. Spreading the trains well in time and space in these areas has a big impact on the passenger robustness, i.e. the total travel time in practice of all passengers in the railway network in case of frequently occurring small delays. We focus on improving the performance in the bottleneck of the network in order to improve the performance of the whole railway network. This paper proposes a method that builds from scratch a routing plan and a cyclic timetable that optimizes the infrastructure occupation and the passenger robustness. An integer linear routing model assigns, without considering a timetable, every train to a route such that the maximal node usage is minimized and that the number of times that each node is used, is quadratically penalized. Thereafter, a mixed integer linear timetabling model assigns to each train the blocking times at which the nodes on its route, assigned by the routing model, are reserved and released. Different from other approaches is that we focus on the occupation of the railway infrastructure before constructing the timetable. The approach is validated on the complex railway station area of Brussels (Belgium). Our routing plan and timetable from scratch improve the passenger robustness up to 11% compared to a reference timetable and routing plan composed by the Belgian railway infrastructure manager Infrabel and by up to 2% compared to a reference timetable and routing plan from literature.