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A Novel algorithm to Delineate Surface Water Paths on Digital Elevation Model Image With Boundary Element Method

IEEE ACCESS 2022年 10卷 60189-60212页

作者： Chantaveerod, Ajalawit Woradit, Kampol Seagar, Andrew D. Limpiti, Thunyawat Walailak Univ Sch Engn & Technol Dept Elect Engn Ctr Excellence Sustainable Disaster Management Tha Sala 80161 Nakhon Si Thamm Thailand Chiang Mai Univ Dept Comp Engn Fac Engn Optimizat Theory & Applicat Engn Syst OASYS Res G Chiang Mai 50200 Thailand Grif th Univ Sch Engn & Built Environm Gold Coast Qld 4222 Australia Walailak Univ Sch Engn & Technol Dept Elect Engn Tha Sala 80161 Nakhon Si Thamm Thailand

It is well-known that the delineated surface water paths (SWP) from a DEM image are essential in hydrology. Both grid-based and contour-based algorithms were proposed in the literature to improve the delineated SWP position's accuracy. Compared to the grid-based algorithm, the contour-based algorithms usually give more accurate results but require higher computation resources, especially in case of the wide catchment. This paper introduces a new contour-based algorithm which is formulated with the semi-analytical solution of Laplace's partial differential equation with boundary element method. This approach allows the algorithm to determine the SWP in any direction in order to keep the delineated SWP smooth. The proposed algorithm was validated with the standard synthetic surfaces, where theoretical SWPs are known for accuracy evaluation. The obtained SWPs are more accurate than that of the popular grid-based algorithms. Moreover, the proposed algorithm requires less computation resources when considering very long contour lines. In experimentation with a real DEM image, all delineated SWPs are absolute (no broken part) when the contour interval is equal to or less than 20 meters, and the spacing between adjacent discrete elevation data is 20 meters or narrower. This algorithm helps the hydrologists estimate the catchment area, which is useful for water management in flood and drought prevention.

关键词： Prediction algorithms Water resources Surface topography Silicon Electrical engineering Disaster management Computational modeling flow direction algorithm digital elevation model (DEM) surface water path (SWP) boundary element method (BEM)

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An algorithm-Independent Definition of Effective Contour Length and Its Impacts on Pixel-Scale Specific Catchment Area

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WATER RESOURCES RESEARCH 2023年第8期59卷 e2022WR034036-e2022WR034036页

作者： Li, Zhenya Lai, Xijun Shi, Pengfei Yang, Tao Chinese Acad Sci Nanjing Inst Geog & Limnol Key Lab Watershed Geog Sci Nanjing Peoples R China Hohai Univ Natl Key Lab Water Disaster Prevent Nanjing Peoples R China Hohai Univ Yangtze Inst Conservat & Dev Nanjing Peoples R China

Specific catchment area (SCA) is crucial terrain attribute extensively-adopted in topographically-driven modelings, which is function of total contributing area (TCA) and effective contour length (EL). Despite of numerous studies about SCA and TCA, none has focused on the investigation of existing EL definitions and adaption of point-scale SCA concept to two-dimensional pixel of digital elevation model (DEM). This work conducts a systematic research on rationality of existing EL definitions, proposal of new EL definition and concept of pixel-scale SCA on gridded DEM. To overcome the defects of existing EL definitions, a new EL definition based on Triangular Discretization and Spatial Geometry (TDSG) is proposed in this work. SCA concept is extended from point scale to pixel scale for adapting to context of gridded DEM. The solutions of true pixel-scale SCA, TCA, and EL in integral forms are deduced based on the solutions of point-scale SCAs obtained by method of Zhou and Liu (2002, ) or Gallant and Hutchinson (2011, ). Besides, true pixel-scale SCA, TCA, and EL are solved analytically for several synthetic surfaces. Numerical experiments indicate that (a) TDSG definition is superior to all existing EL definitions in physical mechanism, spatial characteristics, and computational precisions on synthetic surfaces and a real-world DEM. (b) Spatial characteristics of SCA are controlled mainly by TCA and tuned slightly by EL, while overall precision of SCA is affected seriously by both TCA and EL. (c) TDSG definition is the only EL definition of responding accurately and sensitively to convergent and dispersive characteristics of local terrains.

关键词： effective contour length (EL) specific catchment area analytical solution EL definition flow direction algorithm

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FD-DBN: flow directed deep belief network for accurate anomaly detection in cloud computing

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2023年第16期36卷 e5592-e5592页

作者： Rajarao, Banavathu Sreenivasulu, Meruva Jawaharlal Nehru Technol Univ Anantapur Dept Comp Sci & Engn Ananthapuramu Andhra Pradesh India JNTUA Ananthapuramu KSRM Coll Engn Dept Comp Sci & Engn Kadapa Andhra Pradesh India Jawaharlal Nehru Technol Univ Anantapur Ananthapuramu 515002 Andhra Pradesh India

Security becomes the key concern in a cloud environment, as the servers are distributed throughout the globe and involve the circulation of highly sensitive data. Intrusions in the cloud are common because of the huge network traffic that paves the way for intruders to breach traditional security systems with sophisticated software. To avoid such problems, intrusion detection systems (IDSs) have been introduced by various researchers. Each IDS was developed to achieve a particular objective, that is, providing security by detecting intrusions. Most of the available IDS are inefficient and are unable to provide accurate classification. Also, some of them are computationally expensive to be implemented in practical scenarios. This article proposes a new and efficient IDS framework that can accurately classify the intrusion type through effective training to address the existing drawbacks. The proposed framework, named flow directed deep belief network (FD-DBN), involves three main phases: pre-processing, clustering, and classification. In pre-processing, certain data mining operations are carried out to clean the data. The clustering phase is carried out using the game-based k-means (GBKM) clustering algorithm. The clustered data is then provided as input to the FD-DBN classification framework, where the training process is carried out. The deep belief network (DBN) training is performed with dataset features, and the flow direction algorithm is adopted for tuning the weight parameters of DBN. Through tuning, the model yielded accurate classification outcomes. The simulations are done in Python 3.6, and the results proved that the proposed framework is much more effective than the existing IDS frameworks.

关键词： classification clustering data mining deep belief network deep learning flow direction algorithm intrusion detection system

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Information gap decision theory with risk aversion strategy for robust planning of hybrid photovoltaic/wind/battery storage system in distribution networks considering uncertainty

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ENERGY 2023年第PartA期278卷

作者： Boroumandfar, Gholamreza Khajehzadeh, Alimorad Eslami, Mahdiyeh Syah, Rahmad B. Y. Islamic Azad Univ Dept Elect Engn Kerman Branch Kerman Iran Univ Medan Area Fac Engn CoE PUIN Medan Indonesia

In this paper, robust planning of hybrid photovoltaic/wind/battery storage (PV/WT/Battery) system is performed in the distribution network to minimize power losses cost, purchasing power cost from the hybrid system as well as purchasing power cost from the upstream network considering uncertainties of network demand and renewable generation using information gap decision theory (IGDT) based on risk aversion strategy (RAS). The decision variables are considered as the optimal installation location and capacity of the hybrid system components in the network as well as the uncertainty radius of the uncertain parameters, which is determined using the flow direction algorithm (FDA), which is inspired by the movement of surface water flow to the pond outlet. The planning problem is implemented with deterministic and robust-based IGDT approaches. The proposed methodology is performed on the IEEE 33- and 69-bus distribution networks. The deterministic results indicate that the optimal hybrid PV/WT/Battery system planning in the networks significantly reduces system costs by injecting the optimal renewable power into the network and the battery power reserve management. The better capability of the FDA in deterministic planning is confirmed compared to the particle swarm optimization (PSO), crow search algorithm (CSA), and moth-flame optimizer (MFO) in achieving lower system cost. Moreover, in the IGDT robust approach, the maximum uncertainty radius of the renewable generation and network load is determined for the different uncertainties budget. The IGDT effectiveness is proved compared with deterministic and Monte Carlo simulation (MCS) methods. The total cost of the 33-bus network in deterministic, IGDT, and MCS is obtained at $ 17978.18, $ 20996.19, and $ 26178.02, respectively, and for the 69-bus network are achieved at $ 16846.26, $ 20215.39, and $ 20597.84, respectively. A comparison of the results showed that the MCS strongly depends on the defined scenarios, is very

关键词： Distribution network Hybrid PV WT Battery system Robust planning Information gap decision theory flow direction algorithm

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An Improved D8-LTD for the Extraction of Total Contributing Area (TCA) by Adopting the Strategies of Path Independency and Local Dispersion

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WATER RESOURCES RESEARCH 2022年第2期58卷 e2021WR030948-e2021WR030948页

作者： Li, Zhenya Shi, Pengfei Yang, Tao Wang, Chao Yong, Bin Song, Ying Hohai Univ State Key Lab Hydrol Water Resources & Hydraul En Ctr Global Change & Water Cycle Nanjing Peoples R China Hohai Univ Sch Earth Sci & Engn Nanjing Peoples R China Yangtze Inst Conservat & Dev Nanjing Peoples R China New Mexico Inst Min & Technol Dept Earth & Environm Sci Hydrol Program Socorro NM 87801 USA

D8-LTD is a path-based flow direction algorithm for estimating total contributing area (TCA). However, the precision of D8-LTD TCA is seriously challenged by the incorporation of flow paths and basic hypothesis of allowing only one receiving pixel. To solve above problems, this work proposes an improved D8-LTD by adopting the strategies of path independency and local dispersion (i.e., LTD-PI-LD). Two indicators are adopted to quantify size and extent precisions of estimated TCAs relative to theoretical TCA. Then, LTD-PI-LD is compared with several typical single-flow-direction (SFD) algorithms (i.e., D8, D8-LTD, LTD-PI) and multiple-flow-direction (MFD) algorithms (i.e., MFD-Quinn, D infinity) on synthetic surfaces. Results indicate that (1) TCA maps of D8 and D8-LTD contain too many singular high-TCA tubes and source pixels, which are caused by the incorporation of flow paths and converging characteristics of SFD algorithms. (2) In MFD algorithms, the problem of artificial dispersion triggers the mechanisms of cross compensation and mutual amplification, leading to high size precision but low extent precision in estimated TCAs. (3) Strategy of path independency prevents the occurrence of high-TCA tubes and effectively reduces the number of source pixels. (4) Both size and extent precisions of D8-LTD TCAs are largely improved by introducing the strategies of path independency and local dispersion. Of all algorithms, LTD-PI-LD obtains the highest/second-highest size precision and the highest extent precision in estimated TCAs. As a whole, LTD-PI-LD shows advantages of high precision in estimated TCAs, low computation cost, high efficiency and robustness to DEM (Digital elevation model) resolution and terrain type.

关键词： flow direction algorithm total contributing area improved D8-LTD path independency local dispersion

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A Method for Dynamical Sub-Watershed Delimitating by No-Fill Digital Elevation Model and Defined Precipitation: A Case Study of Wuhan, China

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WATER 2020年第2期12卷 486-486页

作者： Zhang, Hongping Cheng, Xinwen Jin, Lei Zhao, Dong Feng, Tianjing Zheng, Kun China Univ Geosci Fac Informat Engn Wuhan 430074 Peoples R China Wuhan Univ Engn Sci Fac Informat Engn Wuhan 430200 Peoples R China Yangtze Univ Coll Geophys & Petr Resources Wuhan 434023 Peoples R China

Watershed delimitation is very important in flood control management. The traditional sub-watersheds delimitated by a filling digital elevation model (DEM) may change the real sink area, such that it may not be the best choice in studies sensitive to sub-watershed storage. This paper proposes a dynamical watershed delimitation method using a no-fill DEM and precipitation. it considers a closed sink area containing cells that fully flow into a large special cell, which can flow out when its water level is "higher than outlet". We took Wuhan City as a study area and defined the precipitation in return periods of 1, 5, 20, or 100 years to derive the sub-watersheds. it is found that, in the four delimitations, the ratio of isolated basic units which could not flow outside were 27%, 9%, 5%, and 1%, respectively, as the precipitation increased. The results show that the provided method satisfies the assumption that the sink area might overflow with increased precipitation. The sub-watershed delimitated by the proposed method has higher correlation with the distribution of waterlogging points than those delimitated according to the D8 algorithm. These findings indicate that the proposed method can derive reasonable sub-watershed delimitation and that it may be helpful in the practice of urban flood control management.

关键词： urban flood source flood watershed delimitation sink area flow direction algorithm

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Numerical simulation for run-out extent of debris flows using an improved cellular automaton model

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BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT 2017年第3期76卷 961-974页

作者： Han, Zheng Li, Yange Huang, Jianling Chen, Guangqi Xu, Linrong Tang, Chuan Zhang, Hong Shang, Yonghui Cent South Univ Sch Civil Engn 68 Shaoshan Rd Changsha 410075 Hunan Peoples R China Kyushu Univ Dept Civil & Struct Engn Fukuoka 8190395 Japan Chengdu Univ Technol State Key Lab Geohazard Prevent & Geoenvironm Pro Chengdu 610000 Sichuan Peoples R China Tongji Univ Coll Civil Engn Dept Hydraul Engn Shanghai 200092 Peoples R China

Numerical simulation of the debris-flow process is commonly based on the shallow water equations. However, as a two-phase anisotropic mixture, debris flows display complex rheological behavior, making it difficult to model or to simulate these using standard approaches. In this paper, an improved cellular automaton (CA) model is developed for simulating the extent of debris-flow run-out. The CA model consists of three essential components: cellular space, lattice relation, and transition function. A two-dimensional rectangular cellular space is generated from mesh grid in the digital terrain model data, and the Moore neighborhood type is selected as the lattice relation. We also use a transition function based on a Monte Carlo iteration algorithm to automatically search the flow direction and flow routine. Specifically, this new transition function combines the topography function and persistence function (due to the flow inertia), and is advanced in its ability to avoid certain illogical lateral spreading due to abrupt changes in topography. In addition, in contrast to previous studies, in the present work, we regressed the persistence function from a well-documented flume experiment, rather than using a manipulated constant value as described in earlier empirical studies. Our results show that the debris-flow persistence function is closely related to the channel slope. It approximates the law of cosines at a steep slope and Gamma law at a gentle slope. To illustrate the performance of the improved CA model, we selected the 2010 Yohutagawa debris-flow event in Japan as a case study. Our results show that the simulated deposition perimeter pattern and run-out distance are in high accordance with the data from in situ investigation.

关键词： Debris flow Numerical simulation Cellular automaton model Transition function flow direction algorithm

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Comparison of flow direction algorithms in the Application of the CTI for Mapping Wetlands in Minnesota

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WETLANDS 2014年第3期34卷 513-525页

作者： Rampi, Lian P. Knight, Joseph F. Lenhart, Christian F. Univ Minnesota St Paul MN 55108 USA Dept Forest Resources St Paul MN 55108 USA

Topography has been traditionally used as a surrogate to model spatial patterns of water distribution and variation of hydrological conditions. In this study, we investigated the use of light detection and ranging (lidar) data to derive two Single flow direction (SFD) and five Multiple flow direction (MFD) algorithms in the application of the compound topographic index (CTI) for mapping wetlands. The CTI is defined here as ln [(alpha)/(tan (beta)], where alpha represents the local upslope contributing area and beta represents the local slope gradient. We evaluated the following flow direction algorithms: D8, Rho8, DEMON, D-a MD-a, Mass Flux, and FD8 in three ecoregions in Minnesota. Numerous studies have found that MFD algorithms better represent the spatial distribution of water compared to SFD algorithms. CTI maps were compared to field collected and image interpreted reference data using traditional remote sensing accuracy estimators. Overall accuracy results for the majority of CTI based algorithms were in the range of 81-92 %, with low errors of wetland omission. The results of this study provide evidence that 1) wetlands can be accurately identified using a lidar derived CTI, and 2) MFD algorithms should be preferred over SFD algorithms in most cases for mapping wetlands.

关键词： Wetland mapping Lidar flow direction algorithm Compound topographic index

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Artificial surfaces simulating complex terrain types for evaluating grid-based flow direction algorithms

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INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE 2013年第6期27卷 1055-1072页

作者： Qin, Cheng-Zhi Bao, Li-Li Zhu, A-Xing Hu, Xue-Mei Qin, Biao Chinese Acad Sci Inst Geog Sci & Nat Resources Res State Key Lab Resources & Environm Informat Syst Beijing Peoples R China Univ Wisconsin Dept Geog Madison WI 53706 USA

This article presents a set of artificial surfaces simulating complex terrain types for evaluating the performances of grid-based flow direction algorithms. The proposed artificial surfaces were developed based on sine and cosine functions and thus can simulate four complex terrain types: a convex-centred slope, concave-centred slope, saddle-centred slope and straight-ridge slope;such features are typical and widespread in real landscapes. We analytically solved the theoretical values of specific catchment area (SCA) for the proposed artificial surfaces. Compared with existing artificial surfaces for evaluating flow direction algorithms, the proposed artificial surfaces provide a better representation of common terrain types in the real world. To analyse the feasibility of the proposed artificial surfaces, two sets of artificial digital elevation models (DEMs) were created by sampling the proposed artificial surfaces with different reliefs at a series of resolutions (i.e. 1, 5, 10 and 20m). Four representative flow direction algorithms were applied to these artificial DEMs: D8, D-inf, FD8 and MFD-md. The root mean square error, mean error and standard deviation in the computed SCA from flow direction algorithm show that MFD-md generally yielded lower error under simulated terrain conditions than D8, D-inf and FD8. The cumulative frequency distributions of errors from the tested flow direction algorithms with the proposed artificial DEMs can effectively reflect the inherent characteristics of each algorithm. MFD-md performed more similarly to FD8 in low-relief terrains and more similarly to D-inf in high-relief terrains. The map of errors from each tested algorithm is available for a spatially explicit evaluation of the occurrence of errors. Over most of the area, the D-inf algorithm underestimated the SCA when FD8 overestimated the SCA.

关键词： artificial surface error assessment specific catchment area flow direction algorithm gridded digital elevation models

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