National Science and Technology Center for Disaster Reduction

Taipei, Taiwan

National Science and Technology Center for Disaster Reduction

Taipei, Taiwan

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Chen W.-B.,National Science and Technology Center for Disaster Reduction | Liu W.-C.,National United University | Liu W.-C.,Taiwan Typhoon and Flood Research Institute
Renewable Energy | Year: 2017

The influence of sea level rise on tidal power output and tidal energy dissipation is investigated by means of numerical simulations. The hydrodynamics in the Taiwan Strait were simulated using a new unstructured-grid, depth-averaged numerical model. Eight tidal constituents (M2, S2, N2, K2, K1, O1, P1, and Q1) were used to specify the open boundary conditions to drive the model. The observed data, including the time-series water level and tidal current, were used to validate the numerical model. The model results were in reasonable agreement with the measured data. The values of root mean square error (RMSE) for water level and tidal current are in the ranges of 0.06–0.19 m and 0.12–0.20 m/s, respectively. Moreover, the modeling amplitudes for eight tidal constituents determined using the present model were also similar to those determined using the regional inverse tidal model. The model predicted results indicated that the Penghu Channel is an appropriate location for deploying a tidal power plant because of its deep water (>100 m) and fast tidal current (>1.5 m/s). Furthermore, four sea level rise (SLR) scenarios were adopted to investigate the influence of SLR on tidal energy dissipation and tidal power output in the Penghu Channel. The simulation results showed that the total tidal energy dissipation was 11.23 GW for the baseline condition and increased corresponding to different SLR scenarios. The mean tidal power output was 42.15 MW when the additional turbine friction coefficient was set to 0.225. The extractable tidal energy increased by 1.62 MW, 2.09 MW, 2.63 MW, and 3.52 MW for SLR values of 0.87 m, 1.11 m, 1.40 m, and 1.90 m, respectively. We found that sea level rise increased tidal energy dissipation and energy output in the Penghu Channel. © 2016

Su Y.-F.,National Science and Technology Center for Disaster Reduction | Foody G.M.,University of Nottingham | Muad A.M.,National University of Malaysia | Cheng K.-S.,National Taiwan University
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2012

Combining super-resolution techniques can increase the accuracy with which the shape of objects may be characterised from imagery. This is illustrated with two approaches to combining the contouring and pixel swapping methods of super-resolution mapping for binary classification applications. In both approaches, the output of the pixel swapping method is softened to allow a contour of equal class membership to be fitted to it to represent the inter-class boundary. The accuracy of super-resolution mapping with the individual and combined techniques is explored, including an assessment of the effect of variation in the number of neighbors and zoom factor on pixel swapping based analyses. When combined, the error with which objects of varying shape were represented was typically greatly reduced relative to that observed from the application of the methods individually. For example, the root mean square error in mapping the boundary of an aeroplane represented in relatively fine spatial resolution imagery decreased from 14.41 m with contouring and 4.35 m with pixel swapping to 3.07 m when the approaches were combined. © 2008-2012 IEEE.

Su Y.-F.,National Science and Technology Center for Disaster Reduction | Foody G.M.,University of Nottingham | Muad A.M.,National University of Malaysia | Cheng K.-S.,National Taiwan University
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2012

The mixed pixel problem may be reduced through the use of a soft image classification and super-resolution mapping analyses. Here, the positive attributes of two popular super-resolution mapping methods, based on contouring and the Hopfield neural network, are combined. For a binary classification scenario, the method is based on fitting a contour of equal class membership to a pre-final output of a standard Hopfield neural network. Analyses of simulated and real image data sets show that the proposed method is more accurate than the standard contouring and Hopfield neural network based methods, with error typically reduced by a factor of two or more. The sensitivity of the Hopfield neural network based approaches to the setting of a gain function is also explored. © 2008-2012 IEEE.

Kuo Y.-L.,National Science and Technology Center for Disaster Reduction | Perrings C.,Arizona State University
Environmental and Resource Economics | Year: 2010

What makes recycling work? We study the factors driving household waste disposal and recycling in 18 cities in Taiwan and Japan in order to understand the impact of alternative waste management incentives. We show that this depends on the effect of distinct policies on the relative costs of the main alternative disposal methods: recycling, disposal to landfill and illegal dumping. The willingness both to recycle and to dispose to landfill depends on the relative costs of the waste collection regime, and these are dominated by the time cost of alternative disposal methods. The higher the frequency of waste collection, the less recycling and the more disposal to landfill there will be. This is because frequent collection reduces the marginal time-cost of disposal to landfill. Curbside collection of recyclable material, and the frequency of that collection, has a similar effect on the recycling rate. Although direct incentives, such as unit pricing are important in the waste disposal decision, recycling depends primarily on management of the time-costs it involves. © 2010 Springer Science+Business Media B.V.

Lee H.C.,National Science and Technology Center for Disaster Reduction
Disaster Advances | Year: 2011

This paper presents a method of integrating an environmental impact assessment (EIA) and a social impact assessment (SIA), designed to assist in the management of Taiwan's flood-prone areas. This method is disciplinarily integrative because it includes both an EIA and an SIA. It is methodologically integrative because it encourages both technocratic and participatory approaches and offers a precise way to carry out integrative calculations. The calculation method takes into consideration both how the criterion weights are evaluated and the project's performance scores evaluated based on each criterion. This study also introduces several ways of presenting the final assessment results, allowing appraisers to visualize the stakeholders' overall attitude and prioritize a list as to what aspects of the evaluated project should be improved first.

Lee H.-C.,National Science and Technology Center for Disaster Reduction
Disaster Advances | Year: 2013

This study develops a model that uses the DPSIR (Drivers, Pressures, States, Impacts and Responses) model to elucidate the relations between hazard, risk and society. The DPSIR model is used because it places emphasis on current state as well as time and change. In addition, it talks about chains of causation which helps us understand the different types of causes of disasters. This study compares its proposed model to similar models by UNEP etc. Three major advantages of the model proposed in this study are: (1) Theoretically, this study adds to the literature of disaster risk by combining the idea of DPSIR and disaster risk; (2) Practically, this study provides suggestions regarding how to implement the DPSIR model. It suggests starting from Impacts when analyzing historical cases and beginning from Drivers, Pressures and States when studying potential impacted zones without disaster experience; (3) Practically, the model helps researchers explore the causes of disaster and inspect risk management strategies from different angles (Drivers, Pressures, or States).

Chu J.-L.,National Science and Technology Center for Disaster Reduction | Chu J.-L.,National Cheng Kung University | Yu P.-S.,National Cheng Kung University
Journal of Geophysical Research: Atmospheres | Year: 2010

This study investigates the potential of projecting regional precipitation over Yunlin County using a singular-value-decomposition (SVD) based statistical downscaling scheme to cope with climate change; the change rate of local precipitation and its connection with the variability of large-scale circulation are also discussed. It is found that rainfall over Yunlin County is closely tied to the large-scale circulation over the East Asian monsoon region, and that general circulation models (GCMs) perform reasonably in simulating the mean states of sea level pressure (SLP) and meridional wind field at 850 hPa (V850) over this region. Consequently, the two large-scale variables, SLP and V850, both of which are taken from seven GCMs involving the 20C3M, A1B, and B1 scenarios, are used as predictors for downscaling. The result shows that the downscaling schemes based on these predictors show a skillful and stable performance in reproducing historical seasonal rainfall anomalies over Yunlin County, especially when the strategies of using two predictors and multiple model ensemble (MME) are considered. It also shows that comparing the mean states of 20C3M-downscaled and scenario-projected seasonal local rainfall in the coming 36 years with respect to the period of 1975-2000 reveals a suppressive pattern in the wet season and an increasing pattern in the dry season; the finding may be associated with the strength of large-scale circulation under different scenarios. Overall, this study demonstrates that useful information concerning the impact of climate change on regional precipitation can be obtained by downscaling schemes using outputs of GCMs as predictors. Copyright 2010 by the American Geophysical Union.

Su Y.-F.,National Science and Technology Center for Disaster Reduction
Remote Sensing Letters | Year: 2016

Self-similarity of fractal geometry refers to that a part of an object is similar to the whole. This scale-invariant feature has a certain role to play in super-resolution mapping which is a mapping technique across scale aiming at enhancing spatial resolution of remote-sensing imagery. Unlike other super-resolution mapping methods depending solely on spatial continuity, a self-similar pixel swapping (SSPS) method combining spatial continuity and self-similarity of fractal geometry into original pixel swapping (PS) algorithm is presented here. A self-similar weight function defined from the composition information at pixel scale within a predetermined window is added to the calculation of attractiveness in the standard PS method. The self-similar weight function guides the subpixels within a pixel to arrange spatially similar to the appearance of the composition information at pixel scale. Evaluating with synthetic images and satellite image, the performance of the SSPS is particularly obvious in reproducing objects with sharp corners, linear features and adjacent small objects. © 2016 Taylor & Francis.

Rodriguez-Nikl T.,California State University, Los Angeles | Rodriguez-Nikl T.,Oregon State University | Lee C.-S.,National Science and Technology Center for Disaster Reduction | Hegemier G.A.,University of California at San Diego | Seible F.,University of California at San Diego
Journal of Structural Engineering (United States) | Year: 2012

Measures to prevent progressive collapse of structures include protection of critical elements such as columns. In support of this goal, nine tests were conducted to assess the as-built performance of typical columns and the effectiveness of carbon fiber jackets in improving their performance. A quasi-static load protocol was developed to replicate in the laboratory the damage patterns observed in blast testing in the field. Load-deflection curves (resistance functions) and jacket strain were measured. Jackets were observed to change the failure mode from brittle shear to ductile flexure and to increase the load and displacement capacities of the column. Variations in jacket strain are discussed and experimental results are used to assess predictive models for shear capacity and resistance functions. The data support the use of these models for design but identify some limitations in the resistance functions. © 2012 American Society of Civil Engineers.

Chen P.-Y.,National Chung Hsing University | Chen C.-C.,National Chung Hsing University | Chu L.,National Science and Technology Center for Disaster Reduction | McCarl B.,Texas A&M University
Global Environmental Change | Year: 2015

This paper evaluates the global economic damage arising from the effects of climate change and associated carbon dioxide concentrations on the loss of coral reefs. We do this by first estimating the effects of sea surface temperature and carbon dioxide concentrations on coral cover. We develop a statistical relationship between coral coverage and sea surface temperature that indicates that the effects are dependent on the temperature range. For example, we find that increasing sea surface temperature causes coral coverage to decrease when sea surface temperature is higher than 26.85. °C, with the estimated reduction being 2.3% when sea surface temperature increases by 1%. In addition, we find that a 1% carbon dioxide increase induces a 0.6% reduction in global coral coverage. We also estimate the resultant loss in economic value based on a meta-analysis of the recreational and commercial value of reef coverage and a crude proportional approach for other value factors. The meta-analysis shows that the coral reef value decreases by 3.8% when coral cover falls by 1%. By combining these two steps we find that the lost value in terms of the global coral reef value under climate change scenarios ranges from US$3.95 to US$23.78 billion annually. © 2014 Elsevier Ltd.

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