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In this work, two approaches were employed for estimating the spatiotemporal distribution of seismicity density in Taiwan. With the use of the rate-and-state friction model, a model for short-term forecasting according to the fault-interaction-based rate disturbance due to seismicity was considered. Another long-term forecasting model that involves a smoothing Kernel function is proposed. The application of the models to Taiwan led to good agreement between the model forecast and actual observations. Using an integration of the two approaches, the application was found to be capable of providing a seismicity forecast with a higher accuracy and reliability. To check the stability related to the regression the bandwidth function, the forecasted seismicity rates corresponding to the upper and lower bounds of the 95% confidence intervals are compared. The result shows that deviations within the bandwidth functions had an insignificant impact on forecasting reliability. Besides, insignificant differences in the forecasted rate change were obtained when Aσ was assumed to be between 0.1 and 0.4 bars for the application of the rate-and-state friction model. By considering the maximum Coulomb stress change among the seismogenic depth, the model presents a better forecasting ability than that using any single fixed target depth. The proposed methodology, with verified applicability for seismicity forecasts, could be useful for seismic hazard analyses. [ABSTRACT FROM AUTHOR]

Abstract: Increasing our understanding of typhoon movements remains a priority in the western North Pacific. In this study, the trajectories of typhoons that affected Taiwan between 1986 and 2010 are used for clustering, where each trajectory consists of 6-hourly latitude-longitude positions over two days. We compare the performance of four statistical clustering methods, namely, k-means clustering, fuzzy c-means (FCM) clustering, hierarchical clustering, and normalized cut techniques. The results show that the FCM technique provides sufficient cluster efficiency with a relatively high degree of goodness of fit. FCM identifies six clusters according to the minimum coefficients of variation (CV). The hotspots of the typhoon centers in each cluster are determined by kernel density estimation (KDE). Moreover, the typhoon track belongs to six clusters with different membership degrees in FCM. The typhoon track density map is estimated by combining the KDE hotspot maps associated with the FCM weights. The information could be used in planning for disaster management. [Copyright &y& Elsevier]

Abstract: Finding an efficient method to detect counterfeit banknotes is an imperative task in business transactions. In this paper, we propose a system based on multiple-kernel support vector machines for counterfeit banknote recognition. A support vector machine (SVM) to minimize false rates is developed. Each banknote is divided into partitions and the luminance histograms of the partitions are taken as the input of the system. Each partition is associated with its own kernels. Linearly weighted combination is adopted to combine multiple kernels into a combined matrix. Optimal weights with kernel matrices in the combination are obtained through semi-definite programming (SDP) learning. Two strategies are adopted to reduce the amount of time and space required by the SDP method. One strategy assumes the non-negativity of the kernel weights, and the other one is to set the sum of the weights to be unity. Experiments with Taiwanese banknotes show that the proposed approach outperforms single-kernel SVMs, standard SVMs with SDP, and multiple-SVM classifiers. [Copyright &y& Elsevier]

Seismic attenuation parameters in Taiwan have been obtained by using a modified "MultipleLapse Time Window Analysis" approach in order to take into account the scatteringanisotropy. MLTWA method exploits the spatio-temporal dependence of the ratio betweencoherent and incoherent seismic intensity to determine the scattering and absorptionproperties of a heterogeneous medium. In addition to the mean free path l (or the scatteringquality factor Qsc), the seismic wave propagation is controlled by a parameter g(independent of l) which determines the angular redistribution of energy upon scattering(scattering anisotropy). Preferentially forward (resp. backward) scattering correspondsto g > 0 (resp. g < 0), with g = 0 for isotropic scattering. We use Monte-Carlosimulations to compute Green functions and sensitivity kernels for Qsc, Qi (absorptionquality factor) and g in media with an heterogeneous crust overlying a transparentmantle. We analyse seismic records of local earthquakes with magnitude greater than 3.5which occurred between 1994 and 2016. For each stations, we collect events withina radius of 100 km and a maximum depth of 40 km. About 350000 waveformswith a S/N ratio greater than 4 in the coda are selected. Seismic energy in three15 s time windows from the S-wave arrival are measured in 3 frequency bands(1-2, 2-4,4-8 Hz). To account for site amplification and source amplitude, wenormalize observed energy by the average energy in a late coda window at 65 s fromthe origin time of the earthquakes. For every station, we analyse the normalizedenergy in the three time widows as a function of the hypocentral distance. In order todetermine the attenuation parameters Qsc−1, Qi−1 and g with related errors, weimplement a Levenberg-Marquardt algorithm. To guide the inversion, we use thesensitivity kernels for the attenuation parameters computed with our Monte-Carloapproach. Overall, Taiwan is more attenuating than most orogens with a mean effective scatteringloss (Qsc∗)−1 = Qsc−1(1 − g) about 0.012 and a mean intrinsic absorption Qi−1 about0.009 at 1.5 Hz. Our maps reveals strong lateral variations of attenuation with scale lengthfrom 10 to 100 km. Scattering loss (Qsc∗)−1 varies over more than one order of magnitudeacross Taiwan (between 0.0022 and 0.16 at 1.5 Hz). By contrast, absorption fluctuations areabout 30%. The more attenuating zones are the Coastal Range and the Costal Plain wherescattering dominates over absorption at low frequency, and inversely at high frequency. Theseregions are also characterized by strong backscattering (g < −0.85) at 1.5 Hz and ratherhigh V P∕V S ratio. Scattering becomes much more isotropic at high frequency.We speculate that the observed strong backscattering at low frequency is relatedto strong impedance fluctuations in the crust induced by the presence of fluids. [ABSTRACT FROM AUTHOR]