Application of geospatial technologies in constructing a flash flood warning model in northern mountainous regions of Vietnam: a case study at TrinhTuong commune, Bat Xat district, LaoCai province

The model was constructed based on GIS spatial analyses, combined with Analytic Hierarchy Process (AHP) and Multi-Criterion Analysis method (MCA). The data gathered for the study were mainly from remote-sensing images, statistical data and surveys. Field experiments were conducted in Trinh Tuong Commune, Bat Xat District, Lao Cai province. This is a typical remote mountainous region of Vietnam in which flash floods often occur. The study analyzes and evaluates six primary factors that incite flash flood, namely: geomorphological characteristics, soil properties, forest and fractional vegetation cover types, local drainage basin slopes, maximum average rainfall of various years, and the river/stream density of the region. The zoning map showing flash flood potentials has determined that 19.91% of the area had an extremely high risk of flash flood occurrence, 64.92% of the area had a medium risk, and 15.17% had a low or very low risk. Based on the employment of daily maximum rainfalls as the primary factor, an online flash flood warning model was constructed for areas with a “high” or “very high” risk of flash flood occurrence.

FMI Compliant Approach to Investigate the Impact of Communication to Islanded Microgrid Secondary Control

In multi-master islanded microgrids, the inverter controllers need to share the signals and to coordinate, in either centralized or distributed way, in order to operate properly and to assure a good functionality of the grid. The central controller is used in centralized strategy. In distributed control, Multi-agent system (MAS) is considered to be a suitable solution for coordination of such system. However the latency and disturbance of the network may disturb the communication from central controller to local controllers or among agents or and negatively influence the grid operation. As a consequence, communication aspects need to be properly addressed during the control design and assessment. In this paper, we propose a holistic approach with co-simulation using Functional Mockup Interface (FMI) standard to validate the microgrid control system taking into account the communication network. A use-case of islanded microgrid frequency secondary control with MAS under consensus algorithm is implemented to demonstrate the impact of communication and to illustrate the proposed holistic approach.Comment: Proceedings of the IEEE PES ISGT Asia 2017 conferenc

OPTIMAL PLACEMENT AND ACTIVE VIBRATION CONTROL OF COMPOSITE PLATES INTEGRATED PIEZOELECTRIC SENSOR/ACTUATOR PAIRS

In this study, a finite element model based on first-order shear deformation theory is presented for optimal placement and active vibration control of laminated composite plates with bonded distributed piezoelectric sensor/actuator pairs. The model employs the nine-node isoparametric rectangular element with 5 degrees of freedom for the mechanical displacements, and 2 electrical degrees of freedom. Genetic algorithm (GA) is applied to maximize the fundamental natural frequencies of plates; and the constant feedback control method is used for the vibration control analysis of piezoelectric laminated composite plates. The results of this study can be used to aid the placement of piezoelectric sensor/actuator pairs of smart composite plates as well as for robust controller design

Distributed Orientation Localization of Multi-agent Systems in 3-dimensional Space with Direction-only Measurements

When a group of agents such as unmanned aerial vehicles are operating in 3-dimensional space, their coordinated action in pursuit of some group objective generally requires all agents to share a common coordinate frame or orientations of the coordinate axes of agents up to an unknown coordinate rotation common to all agents, which are simply referred to as having common coordinate axis orientations. Given coordinate axes that are initially unaligned, this paper considers the process of using direction measurements between agent pairs (obtained in their own coordinate frames) to achieve orientation localization, i.e. determination of common coordinate axis orientations, the calculations all being distributed. The process builds on the initial determination of relative orientations of agent pairs in a common coordinate basis. Distributed differential equations then allow determination of a common set of coordinate axis orientations, uniquely up to a common rotation transformation, which can itself be determined if and only if one or more agents have access to global coordinates.This work was supported, in part, by the National Research Foundation (NRF) of Korea under the grants NRF2016M1B3A1A01937575 and NRF-2017R1A2B3007034, and in part, by the Australian Research Council under grants DP-130103610 and DP-160104500, and Data61-CSIRO

VIBRATION ANALYSIS OF CROSS-PLY LAMINATED COMPOSITE DOUBLY CURVED SHALLOW SHELL PANELS WITH STIFFENERS

In this paper, the analytical solution for the cross-ply laminated composite double curved shell panels with stiffeners is presented. Based on the smeared stiffeners technique and the first shear deformation theory (FSDT), the motion equations are derived by applying the Hamilton’s principle. The Navier’s solution for the simply supported boundary condition for all edges is presented. The numerical results are verified with the known results in the literature. The effects of the number of stiffeners, dimensions of stiffeners, and lamination scheme of cross-ply laminated composite doubly curved shell panels on the natural fundamental frequencies are investigated