Search

In the monsoon season, sudden flood events occur frequently in urban areas, which hamper the social and economic activities and may threaten the infrastructure and lives. The use of an efficient large-scale waterlogging sensing and information system can provide valuable real-time disaster information to facilitate disaster management and enhance awareness of the general public to alleviate losses during and after flood disasters. Therefore, in this study, a visual sensing approach driven by deep neural networks and information and communication technology was developed to provide an end-to-end mechanism to realize waterlogging sensing and event-location mapping. The use of a deep sensing system in the monsoon season in Taiwan was demonstrated, and waterlogging events were predicted on the island-wide scale. The system could sense approximately 2379 vision sources through an internet of video things framework and transmit the event-location information in 5 min. The proposed approach can sense waterlogging events at a national scale and provide an efficient and highly scalable alternative to conventional waterlogging sensing methods., 19 pages, 14 figures, under submitting and patenting

For many, 2020 was a year of abrupt professional and personal change. For the aquatic sciences community, many were adapting to virtual formats for conducting and sharing science, while simultaneously learning to live in a socially distanced world. Understandably, the aquatic sciences community postponed or canceled most in-person scientific meetings. Still, many scientific communities either transitioned annual meetings to a virtual format or inaugurated new virtual meetings. Fortunately, increased use of video conferencing platforms, networking and communication applications, and a general comfort with conducting science virtually helped bring the in-person meeting experience to scientists worldwide. Yet, the transition to conducting science virtually revealed new barriers to participation whereas others were lowered. The combined lessons learned from organizing a meeting constitute a necessary knowledge base that will prove useful, as virtual conferences are likely to continue in some form. To concentrate and synthesize these experiences, we showcase how six scientific societies and communities planned, organized, and conducted virtual meetings in 2020. With this consolidated information in hand, we look forward to a future, where scientific meetings embrace a virtual component, so to as help make science more inclusive and global. Published version

This paper develops an automatic density-controlled 2-D and 3-D finite element mesh generation system to solve practical engineering applications in geology, hydraulics, hydrology, water resources, etc. The Delaunay triangulation method is adopted to create triangular meshes based on the required density specified by users. A triangle-to-quadrilateral conversion method is used to generate quadrilateral meshes adaptively. Density control algorithms of adaptive 2-D mesh generation are presented to satisfy the various requirements of the overland and subsurface hydrogeology and water resources in the actual target area. According to the alignment of boundary edges and distribution of surface nodes, this paper proposes the main algorithm and basic criteria to generate supplementary triangle and quadrilateral meshes for filling the water regions of river reaches and junctions with storage. A stretch mode is proposed to generate triangular prism and hexahedral meshes by stretching the 2-D mesh into 3-D space based on the materials of geometric regions. The 1-D/2-D/3-D correspondence between the finite element mesh and the river reaches, junctions with and without storage, ponds, lakes, control structures and fractures is established. Finally, practical 2-D and 3-D meshing applications are provided to demonstrate the accuracy and effectiveness of the finite element mesh generator developed in this paper.

This research developed an automatic two-dimensional finite element meshing system to resolve practical engineering problems in the fields of geology, hydrology, and water resources. This system first used the Delaunay triangulation method to create reasonable-density triangular mesh and then converted it into quadrilateral mesh by combining proper pairs of adjacent triangles. A series of combination patterns aiming at three cases were established. The effect of the number of boundary edges on the subsequent meshing procedures were studied and summarized. For the geometry with multiple domains an adjustment method is proposed to completely eliminate the residual triangles during quadrilateral meshing through adjusting the number of boundary edges in each loop to be even. A special boundary loop identification method is proposed for priority treatment. Corresponding treatment methods aimed at three different situations are established for common boundary loops. For a certain boundary loop with an odd number of boundary edges, the appropriate edge for new point insertion is determined by the position properties and relative density errors. Practical applications confirm that the method proposed in this paper could successfully implement the full conversion from the triangular mesh to the quadrilateral mesh.

With the increasing climatic extremes, the frequency and severity of urban flood events have intensified worldwide. In this study, image-based automated monitoring of flood formation and analyses of water level fluctuation were proposed as value-added intelligent sensing applications to turn a passive monitoring camera into a visual sensor. Combined with the proposed visual sensing method, traditional hydrological monitoring cameras have the ability to sense and analyze the local situation of flood events. This can solve the current problem that image-based flood monitoring heavily relies on continuous manned monitoring. Conventional sensing networks can only offer one-dimensional physical parameters measured by gauge sensors, whereas visual sensors can acquire dynamic image information of monitored sites and provide disaster prevention agencies with actual field information for decision-making to relieve flood hazards. The visual sensing method established in this study provides spatiotemporal information that can be used for automated remote analysis for monitoring urban floods. This paper focuses on the determination of flood formation based on image-processing techniques. The experimental results suggest that the visual sensing approach may be a reliable way for determining the water fluctuation and measuring its elevation and flood intrusion with respect to real-world coordinates. The performance of the proposed method has been confirmed, it has the capability to monitor and analyze the flood status, and therefore, it can serve as an active flood warning system.

This paper developed an automatic quadrilateral meshing system to resolve the numerical simulation problems in the fields of geological mechanics, hydraulics, hydrology, and water resources. An improved combination method was proposed to automatically convert Delaunay triangular meshes into quadrilateral meshes by combining adjacent pairs of triangles through searching advancing-front edges. In order to implement the full conversion, seven combination patterns were established to select appropriate pairs of adjacent triangles. To handle the residual triangles, each nearest pair of residual triangles were moved to each other along a proper path and recombined into a quadrilateral. The movement of residual triangles was implemented through the destruction and reconstruction of neighboring quadrilaterals. A transformation template was established to convert the only residual triangle in each domain into quadrilaterals. To ensure the geometric topology of the resulting mesh, nine topological optimization modes were proposed to improve the topological connections of the degenerated quadrilaterals especially those on the boundaries of the mesh. An area-weighted Laplacian method was used to smooth the interior nodes, and an objective function method was employed to adjust the positions of special nodes. Finally, practical examples of two treatment strategies for river and overland flows were provided to demonstrate the accuracy and reliability of the meshing and optimization algorithms proposed in this paper.

Large amount of video data is stored and distributed in wide variety of application. Due to the fast video material increases, manage and query of video become more and more important. In this paper, we address a temporal signature representation and similarity model to retrieval the similar video within database by video query. Experimental results on real date are presented. The experimental results show that the statistical approach permits accurate query of video clip, in particular, the performance of the approach was found extremely satisfactory with determine all similar video in database.

This paper focuses on flood-region detection using monitoring images. However, adverse weather affects the outcome of image segmentation methods. In this paper, we present an experimental comparison of an outdoor visual sensing system using region-growing methods with two different growing rules—namely, GrowCut and RegGro. For each growing rule, several tests on adverse weather and lens-stained scenes were performed, taking into account and analyzing different weather conditions with the outdoor visual sensing system. The influence of several weather conditions was analyzed, highlighting their effect on the outdoor visual sensing system with different growing rules. Furthermore, experimental errors and uncertainties obtained with the growing rules were compared. The segmentation accuracy of flood regions yielded by the GrowCut, RegGro, and hybrid methods was 75%, 85%, and 87.7%, respectively.

In the era of information explosion, the traditional approach to storing data have faced challenges due to the rapid growth of information. It becomes an important issue when we come to processing the large dataset and trying to retrieve the useful information from a big database. This paper presents an effective scheme which employs hybrid cache architecture on the existing database system to enhance the query performance without increasing the hardware cost. Our scheme can be applied to satisfy the traditional database query over the Internet. The experimental results collected from a practical application show that the data query can be speeded up to 26 times. Performance evaluation shows that the response time of queries is less than 0.02 seconds when the query hits the shared memory cache. The proposed architecture can be easily applied to the traditional SQL database to accelerate the database query without significant programing efforts.

This study proposes a real-time monitoring system to integrate the supportive flood-related information for hazard mitigation purposes. Through integrating photography, communication, geometric information display and network technology, this system can provide the real-time monitoring images at the critical gauge stations, inundation-prone areas and important hydraulic facilities during floods. With the development of mobile monitoring modules, the maneuverability of users and facilities could be significantly improved. Users can easily employ mobile phones to receive or report real-time flood-related information at any place and time. Furthermore, the water-level image recognition method is developed and applied to the selected monitoring stations for acquiring early warning of flood events. In final, an application scenario is given to illustrate how this system can greatly improve the effectiveness and efficiency of emergency responses to flood hazard mitigation for the decision-makers.

Flood hazard prevention and mitigation is an emergent environmental problem. Traditional flood monitoring devices operated under adverse environmental conditions are typically influenced by changes in weather conditions such as haze, fog and rain. Consequently, the video images obtained from such devices are often blurred or damaged, increasing the possibility of erroneous assessments in hazard mitigation processes. To ensure the efficient use of image analysis technology to improve degraded images captured under hazy weather conditions, this study proposes an automated single image dehazing method for flood monitoring. This method is based on the dark channel prior for the removal of haze from a single image. The concept of the dark channel prior is that most local patches in haze-free outdoor images contain some pixels having extremely low intensities in at least one colour channel. When this dark channel prior is used, the thickness of haze in the image can be directly estimated and a high-quality haze-free image can be obtained. The proposed method can be used to accurately improve flood detection and monitoring results. The ability to detect and remove haze from a single image is a crucial function when applying automated computer vision to disaster-monitoring applications. The experimental results show that the proposed method can efficiently alleviate the degradation of surveillance images and effectively identify flooded regions in particular areas.

SUMMARY 1. We used high-frequency in situ dissolved oxygen measurements to investigate the seasonal variability and factors regulating metabolism in a subtropical alpine lake in Taiwan between May 2004 and October 2005, specifically exploring how the typhoon season (from June or July to October) affects lake metabolism. 2. Gross primary production (GPP) and ecosystem respiration (R) both peaked in early summer and mid-autumn but dropped during the typhoon season and winter. Yuan-Yang Lake is a net heterotrophic ecosystem (annual mean net ecosystem production )39.6 lmole O2 m )3 ). 3. Compared to the summer peaks, seasonal averages of GPP and R decreased by approximately 50% and 25%, respectively, during the typhoon season. Ecosystem respiration was more resistant to external disturbances than GPP and showed strong daily variation during typhoon seasons. 4. Changes in the quality and quantity of dissolved organic carbon controlled the temporal dynamics and metabolic regulation. External disturbances (typhoons) caused increased allochthony, increasing DOC and water colour and influencing lake metabolism. 5. Seasonal winter mixing and typhoon-induced water mixing in summer and autumn play a key role in determining the extent to which the lake is a seasonal carbon sink or source to the atmosphere.

This paper illustrates a human-centered cyberinfrastructure (CI) for conducting scientific and engineering grid applications. CI comprises computing systems, data, information resources, networking, digitally enabled-sensors, instruments, observatories, and virtual organizations, along with an interoperable suite of software services and tools. The Taiwan Knowledge Innovation National Grid (KING) began with a human-centered, application-driven CI. In addition to the development of usual CI which covers the planning of required resources, technology development and forming the environment for research and education, our CI emphasizes how to connect experts and communities via collaborative technologies to work as a virtual organization. The approach technologically leads to bridging and balance between intensive computing which is the base of CI, and pervasive computing which allows a wide variety of access to remote and local intelligence. In applications, topics strongly related to people's living in Taiwan, such as epidemics alleviation support, medical care, flood mitigation and ecological conservation, are of interest and used to drive the CI development. It enables human-life related applications as a result. The accomplishments and social impacts associated with the applications are highlighted in this article. The Grid middleware and core technologies utilized by individual applications and impacts are also explored in this paper. It is found that pervasive computing technology plays a significant role in human-life related grid applications, and the demand for data grid support to applications is more than within the intensive computing category. With the accumulated capability, the human-centered CI can be extended to serve business and industry, and further developed to play a key position in the Asia Pacific cyber-education and research collaboration.

This book gives a start-to-finish overview of the whole Fish4Knowledge project, in 18 short chapters, each describing one aspect of the project. The Fish4Knowledge project explored the possibilities of big video data, in this case from undersea video. Recording and analyzing 90 thousand hours of video from ten camera locations, the project gives a 3 year view of fish abundance in several tropical coral reefs off the coast of Taiwan. The research system built a remote recording network, over 100 Tb of storage, supercomputer processing, video target detection and tracking, fish species recognition and analysis, a large SQL database to record the results and an efficient retrieval mechanism. Novel user interface mechanisms were developed to provide easy access for marine ecologists, who wanted to explore the dataset. The book is a useful resource for system builders, as it gives an overview of the many new methods that were created to build the Fish4Knowledge system in a manner that also allows readers to see how all the components fit together.

Gallium melting in a rectangular cavity heated from the side wall has been extensively studied. Since the previously simulated results were not consistent and the myth of a grid-converged solution remained, we reexamine this problem using the thermally driven mushy cell tracking method to clarify whether the solution is physically correct. In the study, the computational domain is separated into solid-phase and liquid-phase regions, with the mushy cell placed in between. The governing equations for the thermofluid transport are expressed in terms of the primitive variables and are discretized in the stationary unstructured grid using the finite-volume formulation. The mushy cell tracking equation is derived under the mass and energy balance laws to capture the mushy cell front. With the variables located in the cell centers, the distinguishing characteristic of the present tracking algorithm lies in the specification of constant melting or freezing temperature at the center of the mushy cells without cons...

Surface meshing plays a crucial role in mesh generation. Usually, surface meshing methods in three dimensions generate meshes relying on prescribed patch interpolation. In this study, an approach of surface meshing directly on a set of unorganized points is developed, which consists of a mesh triangulation and a conversion scheme for primary triangular and quadrilateral surface meshes, a high order C 1 surface function reconstruction, and a micro-genetic algorithm (MGA) to smooth the meshes. Practical cases are given to demonstrate its successful performance and its versatility. � 2006 Elsevier B.V. All rights reserved.

Electron tomography is a powerful technique for deriving 3D structural information from biological specimens. As advanced instrumentation, networking, and grid computing are applied to electron tomography and biological sciences in general, much work is needed to integrate and coordinate these advanced technologies in a transparent way to deliver them to the end user. The Telescience Portal (http://gridport.npaci.edu/Telescience) is a web-based solution for end-to-end electron tomography that centralizes applications and seamlessly interfaces with the grid to accelerate the throughput of data results. In this paper we will describe the architecture and design of the Telescience Portal in the context of our experiences leading up to and including the iGrid2002 workshop. We will examine the lessons learned in developing the production Telescience environment, leveraging a successful international collaboration with groups in Japan and Taiwan, building end-to-end native IPv6 networks across continents, and examining IPv6 enabled mechanisms for transferring large data from two unique, remotely accessible high performance scientific instruments. Traditional computer science communities develop next generation technologies. Applications like Telescience drive these next generation technologies into production quality applications for everyday research needs.