2,761 research outputs found

    Alternative measurement configurations for extracting bulk optical properties using an integrating sphere setup

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    The usual approach for estimating bulk optical properties using an integrating sphere measurement setup is by acquiring spectra from three measurement modes namely collimated transmittance (Tc), total transmittance (Td), and total diffuse reflectance (Rd), followed by the inversion of these measurements using the adding–doubling method. At high scattering levels, accurate acquisition of Tc becomes problematic due to the presence of significant amounts of forward-scattered light in this measurement which is supposed to contain only unscattered light. In this paper, we propose and investigate the effectiveness of using alternative sets of integrating sphere measurements that avoid the use of Tc and could potentially increase the upper limit of concentrations of suspensions at which bulk optical property measurements can be obtained in the visible–near-infrared (Vis-NIR) region of the spectrum. We examine the possibility of replacing Tc with one or more reflectance measurements at different sample thicknesses. We also examine the possibility of replacing both the collimated (Tc) and total transmittance (Td) measurements with reflectance measurements taken from different sample thicknesses. The analysis presented here indicates that replacing Tc with a reflectance measurement can reduce the errors in the bulk scattering properties when scattering levels are high. When only multiple reflectance measurements are used, good estimates of the bulk optical properties can be obtained when the absorption levels are low. In addition, we examine whether there is any advantage in using three measurements instead of two to obtain the reduced bulk scattering coefficient and the bulk absorption coefficient. This investigation is made in the context of chemical and biological suspensions which have a much larger range of optical properties compared to those encountered with tissue

    When Causal Intervention Meets Adversarial Examples and Image Masking for Deep Neural Networks

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    Discovering and exploiting the causality in deep neural networks (DNNs) are crucial challenges for understanding and reasoning causal effects (CE) on an explainable visual model. "Intervention" has been widely used for recognizing a causal relation ontologically. In this paper, we propose a causal inference framework for visual reasoning via do-calculus. To study the intervention effects on pixel-level features for causal reasoning, we introduce pixel-wise masking and adversarial perturbation. In our framework, CE is calculated using features in a latent space and perturbed prediction from a DNN-based model. We further provide the first look into the characteristics of discovered CE of adversarially perturbed images generated by gradient-based methods \footnote{~~https://github.com/jjaacckkyy63/Causal-Intervention-AE-wAdvImg}. Experimental results show that CE is a competitive and robust index for understanding DNNs when compared with conventional methods such as class-activation mappings (CAMs) on the Chest X-Ray-14 dataset for human-interpretable feature(s) (e.g., symptom) reasoning. Moreover, CE holds promises for detecting adversarial examples as it possesses distinct characteristics in the presence of adversarial perturbations.Comment: Noted our camera-ready version has changed the title. "When Causal Intervention Meets Adversarial Examples and Image Masking for Deep Neural Networks" as the v3 official paper title in IEEE Proceeding. Please use it in your formal reference. Accepted at IEEE ICIP 2019. Pytorch code has released on https://github.com/jjaacckkyy63/Causal-Intervention-AE-wAdvIm

    One-Class-at-a-Time Removal Sequence Planning Method for Multiclass Classification Problems

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    Using dynamic programming, this work develops a one-class-at-a-time removal sequence planning method to decompose a multiclass classification problem into a series of two-class problems. Compared with previous decomposition methods, the approach has the following distinct features. First, under the one-class-at-a-time framework, the approach guarantees the optimality of the decomposition. Second, for a K-class problem, the number of binary classifiers required by the method is only K-1. Third, to achieve higher classification accuracy, the approach can easily be adapted to form a committee machine. A drawback of the approach is that its computational burden increases rapidly with the number of classes. To resolve this difficulty, a partial decomposition technique is introduced that reduces the computational cost by generating a suboptimal solution. Experimental results demonstrate that the proposed approach consistently outperforms two conventional decomposition methods

    An Economy-wide Analysis of Impacts of WTO Tiered Formula for Tariff Reduction on Taiwan

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    In this study we use Taiwan as a case study to provide an economy-wide analysis of impacts on Taiwan of WTO tariff reduction schemes with different combinations of thresholds and reduction rates. The model we utilized in this study is Taiwan General Equilibrium Model with a WTO module (TAIGEM-WTO, hereafter) that is a multi-sectoral computable general equilibrium (CGE) model of the Taiwan's economy derived from Australian ORANI model (Dixon, Parmenter, Sutton and Vincent, 1982). Simulation results show that results are more sensitive to the scheme of tariff-reduction (i.e., Category 1, 2, and 3) than the tiered levels (i.e., A, B, C, and D) and as a strategy we should pay more attention to the arguments related to the amounts of tariff-reduction. Moreover, changes in nominal average tariff rates are more sensitive and shocks to the economy are more severe when we change the tariff reduction categories rather than the tiered levels. This conclusion also applies to the tiered reduction case when only sensitive products are considered. Finally, simulations with sector's bound rate calculated using arithmetic means have bigger effects than those using import values as weights. Therefore, sector's bound rate using import values as weights would be preferred.International Relations/Trade,

    Interactions Between Reinforcement Corrosion and Chloride Ion Diffusion in Mortar

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    This study explored the diffusion of the chloride ions influenced by the reinforcement corrosion in the mortar. It is believed that, during the corroding process, a small current is generated at the surface of the reinforcement. Such current is supposed to influence the diffusion of the chloride ions, but the relationship between both was not well studied in the literature. In this study, the corroded reinforcements were prepared by applied currents. Reinforced mortar specimens with w/c of 0.6 were then prepared and cured by either salt or fresh water. Results showed that the chloride ion distribution was likely associated with the reinforcement corrosion. During the early hydration, the chloride ions were attracted by the reinforcement corrosion in the specimens prepared with fresh water and cured in salt water. The concentration of the chloride ions near the surface of the reinforcement was increased with the increases of the charging time during the preparation for the corroded reinforcement. On the contrary, the chloride ions were likely bound in those specimens prepared with salt water and cured by saturated lime water. The concentration of the chloride ions near the surface of the reinforcement was higher than those near the outer surface. However, such influencing effects were not clear in the long term, possibly due to the hydration. The results of this study show that the reinforcement corrosion have influences on the diffusion of the chloride ions and such effect should be considered during the refinement of the traditional chloride ion diffusion models

    The Influence of Family Communication Patterns on Adolescents' Decision-Making Process

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    While studies around children and adolescents' influence on family purchasing have been greatly focused on, little investigation has been on family communication patterns influencing on children and adolescents' decision-making process. In order to fill the gap, this study examines the effect of family communication patterns on teenagers' (aged 16-18) decision-making process. The results indicate that in the information seeking stage, the adolescents in pluralistic and consensual family communications score higher in acquiring information from mothers than other teens. However, gaining information from fathers occurs to be less preferred in all types of family communication clusters. In the evaluation and purchasing stages, the teens in all family communication categories do not like to choose the products preferred by fathers and mothers; in addition, they are unlikely to ask fathers and mothers to purchase products with them either. With regard to the adolescents in protective and consensual family communications, they share some common ground in the entire decision-making process. To be more precise, they have higher desire to gain information from TV advertising, to assess products by well-known brand names, and to ask friends to go shopping with

    Asian Primate Species Richness Correlates with Rainfall

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    Previous studies of meta-analyses found significantly positive correlations between primate species richness and rainfall for Africa, Madagascar and the Neotropics, with the exception of Asia, leaving the open question whether that anomaly is the result of sampling bias, biogeography, or some other factor. This study re-examines the question using modelled data, with primate species richness data from the Southeast Asian Mammals Databank and rainfall data from the Climatic Research Unit. Data processing with Geographical Information Systems resulted in 390 sample points. Reduced major axis and ordinary least squares regressions were employed to examine the relationship for six regions, including the whole study area of Southeast Asia, and the subareas of Huxley West, Huxley East, Mainland Southeast Asia, Borneo, and Sumatra. The results showed a significant positive relationship between primate species richness and mean annual rainfall for Southeast Asia (r = 0.26, P,0.001). Comparing the results for the large islands and Mainland Southeast Asia showed that Sumatra had the highest correlation (r = 0.58; P,0.05). After controlling for the major biogeographic effect associated with Huxley’s Line, our results showed that primate species richness is positively associated with mean annual rainfall in Southeast Asia. Our findings contrast to prior studies of meta-analyses that showed no relationship between rainfall and primate species richness in Asia, and thereby bring Asia into agreement with results showing significant positive correlations between rainfall and primate species richness everywhere else in the world. The inference is that previous anomalous results for Asia were result of sampling bias in the meta-analysis

    A CONJOINT STUDY OF THE RELATIONSHIP BETWEEN WEBSITE ATTRIBUTES AND CONSUMER PURCHASE INTENTIONS

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    This paper extends and modifies the Schaupp and Belanger model (2005) to develop and propose a model of on-line shopping intentions. Four on-line websites were designed as the test platforms. Respondents of this study were asked to visit these web-sites that represent differing shopping scenarios before they completed our on-line survey. Findings of this study are as follows. First, on-line contract signing mechanism was ranked as the most desired option in building trust in on-line shopping websites by all respondents. Second, respondents of this study were found able to be categorized into three groups according to the website factors they valued most. The three were logistic/security, security/trust, and convenience/trust. The specific attributes of on-line shopping websites valued most within each of the three groups are discussed in this paper. This study presents findings that support the use of many existing on-line technologies that have been found little used in on-line shopping websites such as digital certificate and on-line contracting. The inclusion of these technologies in on-line shopping websites may increase the cost of building and maintaining them and may create worries about user inconvenience. However, it is important that these technologies increase the attractiveness of the on-line shopping website and web surfers purchase intentions
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