4,722 research outputs found

    Regularization and Kernelization of the Maximin Correlation Approach

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    Robust classification becomes challenging when each class consists of multiple subclasses. Examples include multi-font optical character recognition and automated protein function prediction. In correlation-based nearest-neighbor classification, the maximin correlation approach (MCA) provides the worst-case optimal solution by minimizing the maximum misclassification risk through an iterative procedure. Despite the optimality, the original MCA has drawbacks that have limited its wide applicability in practice. That is, the MCA tends to be sensitive to outliers, cannot effectively handle nonlinearities in datasets, and suffers from having high computational complexity. To address these limitations, we propose an improved solution, named regularized maximin correlation approach (R-MCA). We first reformulate MCA as a quadratically constrained linear programming (QCLP) problem, incorporate regularization by introducing slack variables in the primal problem of the QCLP, and derive the corresponding Lagrangian dual. The dual formulation enables us to apply the kernel trick to R-MCA so that it can better handle nonlinearities. Our experimental results demonstrate that the regularization and kernelization make the proposed R-MCA more robust and accurate for various classification tasks than the original MCA. Furthermore, when the data size or dimensionality grows, R-MCA runs substantially faster by solving either the primal or dual (whichever has a smaller variable dimension) of the QCLP.Comment: Submitted to IEEE Acces

    Naphthalimide Trifluoroacetyl Acetonate: A Hydrazine-Selective Chemodosimetric Sensor

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    The trifluoroacetyl acetonate naphthalimide derivative 1 has been synthesized in good yield. In acetonitrile solution, compound 1 reacts selectively with hydrazine (NH2NH2) to give a five-membered ring. This leads to OFF-ON fluorescence with a maximum intensity at 501 nm as well as easily discernible color changes. Based on a readily discernible and reproducible 3.9% change in overall fluorescence intensity, the limit of detection for 1 is 3.2 ppb (0.1 mu M), which is below the accepted limit for hydrazine set by the U.S. Environmental Protection Agency (EPA). Compound 1 is selective for hydrazine over other amines, including NH4OH, NH2OH, ethylenediamine, methylamine, n-butylamine, piperazine, dimethylamine, triethylamine, pyridine, and is not perturbed by environmentally abundant metal ions. When supported on glass-backed silica gel TLC plates, compound 1 acts as a fluorimetric and colorimetric probe for hydrazine vapor at a partial pressure of 9.0 mm Hg, with selectivity over other potentially interfering volatile analytes, including ammonia, methylamine, n-butylamine, formaldehyde, acetaldehyde, H2O2, HCl, and CO2 being observed. Probe 1 can also be used for the detection of hydrazine in HeLa cells and does so without appreciable interference from other biologically abundant amines and metal ions.U.S. National Science Foundation CHE-1057904Robert A. Welch Foundation F-1018CRI project grant from National Research Foundation of Korea (NRF)Korea government (MSIP) 2009-0081566Chemistr

    Precarious working youth and pension reform in the Republic of Korea and Italy

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    This paper focuses on two aspects of the welfare state: the old age pension system and the labor market, where the majority of youth are working in precarious jobs. We discuss the interplay between pension funds and the increase in young atypical workers by studying the case of Italy and the Republic of Korea, closely analyzing the projected benefit level of both standard and nonstandard workers among the youth population in Korea in order to assess where young workers will find themselves after retirement age and what Korea can learn from the case of Italy.This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012S1A3A2033416)

    Estimates of Discharge Coefficient in Levee Breach Under Two Different Approach Flow Types

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    The amount of released water (discharge) in a levee breach is a primary input variable to establish an emergency action plan for the area next to the levee. However, although several studies have been conducted, there is still no widely applicable discharge coefficient formula; this needs to be known to estimate discharge amount through an opening caused by a levee breach. Sometimes, the discharge coefficient developed for a sharp crested side weir is used to rate the discharge, but, in case of a levee breach, the resulting geometry and flow types are similar to that over a broad crested weir. Thus, in this study, two different openingsโ€”rectangular and trapezoidal shapeโ€”are constructed in the center of a levee at a height of 0.6m to replicate levee breach scenarios, and the effect of two different approach flow typesโ€”the river type approach and reservoir type approachโ€”are explored to suggest a discharge coefficient formula applicable for discharge rating for a levee breach. The results show that the ratio of head above the bottom of an opening and the opening width is a key variable for calculating the discharge coefficient of a reservoir type, but the approach Froude number should also be considered for a river type approach. The measured data are used to improve rating equations and will be useful in the future to validate computational fluid dynamics simulations of wave propagation during levee failure into the inundation area

    Special Report - Smart Projects in Smart Asia

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    What is Smart? What does Smart mean in todays context? Before technology, the term was used to refer to human excellence in our actions, mannerisms, facial expressions, languages and thoughts. More recently, its definition has been narrowed down to describe the capacity of artificial intelligence. Smart is the new thing. Products that are not Smart are now objects of the past and the future will be all about creating Smart-er products and services. The rapid development of personal or family friendly technology such as Smartphones, Smart tablets, Smart TV, etc. is analogous with the evolution from using a broom to clean the living room to handling an automatic vacuum cleaner. Smart scenarios and technological innovations of the future have already been extensively studied and explored. The idea that hundreds of remote sensors will receive information and analyze it with a microprocessor, and then carry out ones unconscious command, is one that we can largely relate with a desirable and Smart future. Yet are these complicated processes and automated actions really the Smart environment we are looking for? ์Šค๋งˆํŠธํ•˜๋‹ค๋Š” ๊ฒƒ ์˜ค๋Š˜๋‚  ์Šค๋งˆํŠธํ•˜๋‹ค๋Š” ๊ฒƒ์€ ๋ฌด์—‡์„ ์˜๋ฏธํ•˜๋Š”๊ฐ€? ํ–‰๋™, ์ •์„œ, ํ‘œ์ •, ์–ธ์–ด, ์ƒ๊ฐ ๋“ฑ ์ธ๊ฐ„์˜ ์ด์„ฑ๊ณผ ์ง€์„ฑ์˜ ๋ชจ๋“  ๋ถ€๋ถ„์— ๊ฑธ์ณ ์šฐ์ˆ˜ํ•จ ์ง€์นญํ•˜๋˜ ์ด ํ˜•์šฉ์‚ฌ๋Š” ์ธ๊ฐ„์ด ์•„๋‹Œ ์ธ๊ณต์ง€๋Šฅ์˜ ๊ธฐ๋Šฅ์˜ ์šฐ์ˆ˜ ์„ฑ์„ ๋œปํ•˜๋Š” ์ข์€ ์˜๋ฏธ๋กœ ๋ณ€ํ™”ํ–ˆ๋‹ค. ์Šค๋งˆํŠธ๊ฐ€ ๊ด€๊ฑด์ด๋‹ค. ์š”์ฆ˜ ์‹œ๋Œ€์— ์Šค๋งˆํŠธํ•˜์ง€ ์•Š์€ ๋ฌผ๊ฑด ์ด๋ฉด ์˜›๊ฒƒ์ด ๋˜๊ณ , ์Šค๋งˆํŠธํ•œ ์ •๋„๊ฐ€ ๋ฏธ๋ž˜๋ฅผ ๋งŒ๋“ค์–ด๋‚ด๋Š” ์ฒ™๋„๊ฐ€ ๋˜์—ˆ๋‹ค. ์Šค๋งˆํŠธํฐ, ์Šค๋งˆํŠธํƒ€๋ธ” ๋ ›, ์Šค๋งˆํŠธTV ๋“ฑ ๊ฐœ์ธ์šฉ, ๊ฐ€์ •์šฉ ์ „์ž์ œํ’ˆ์„ ์œ„์‹œํ•œ ์ƒํ™œ์ „๋ฐ˜์— ์†Œ์šฉ๋˜๋Š” ์Šค๋งˆํŠธํ•จ์˜ ์ง„ํ™” ๋Š” ๋งˆ์น˜ ์†์œผ๋กœ ๋งˆ๋ฃจ๋ฐ”๋‹ฅ์„ ํ›”์น˜๋˜ ์‹œ์ ˆ์—์„œ ์‚ฐ์—…์‚ฌํšŒ๋ฅผ ๊ฑธ์ณ ์ „๊ธฐ๊ธฐ๊ณ„๋ฅผ ๊ฐ€์ง„ ์ง„๊ณต์ฒญ์†Œ๊ธฐ์˜ ์ง„ํ™”์— ๊ฑธ๋งž๋‹ค. ์Šค๋งˆํŠธํ•œ ํ™˜๊ฒฝ์— ๋Œ€ํ•œ ๊ธฐ์ˆ ๊ฐœ๋ฐœ๊ณผ ๋ผ์ดํ”„์‹œ๋‚˜๋ฆฌ์˜ค๋Š” ์ด๋ฏธ ์˜ค๋ž˜์ „๋ถ€ํ„ฐ ์ง„ํ–‰๋˜ ์–ด ์™”๋‹ค. ์ˆ˜์‹ญ๊ฐœ, ์ˆ˜๋ฐฑ๊ฐœ์˜ ์„ผ์„œ๊ฐ€ ์ •๋ณด๋ฅผ ๋ฐ›์•„๋“ค์ด๊ณ  ๋งˆ์ดํฌ๋กœ ํ”„๋กœ์„ธ์„œ๊ฐ€ ์ด๋ฅผ ๋ถ„์„ํ•˜์—ฌ ๋‚ด ๊ฐ€ ์›ํ•˜๋Š” ๋™์ž‘์„ ์–ด๋–ค ๋ช…๋ น์–ด ์—†์ด๋„ ์›๊ฒฉ์œผ๋กœ ์ œ์–ดํ•˜๊ณ  ๋ผ์ดํ”„์Šคํƒ€์ผ์„ ๊ด€๋ฆฌํ•ด ์ฃผ๋Š” ๋˜‘๋˜‘ ํ•œ ํ™˜๊ฒฝ์ด ์ธ๋ฅ˜๊ฐ€ ์ถ”๊ตฌํ•˜๋Š” ๋ฏธ๋ž˜๋ผ๋Š” ๊ฒƒ์€ ์šฐ๋ฆฌ ๋ชจ๋‘๊ฐ€ ๋‹ค ์•Œ๊ณ  ์žˆ๋Š” ๋ฐ”์ด๋‹ค. ๊ทธ๋Ÿฐ๋ฐ ์šฐ๋ฆฌ๊ฐ€ ์›ํ•˜๋Š” ์Šค๋งˆํŠธํ•จ์€ ์ด๋ ‡๊ฒŒ ๋ณต์žกํ•œ ํ”„๋กœ์„ธ์Šค๊ฐ€ ์ง„ํ–‰๋˜๋Š” ํ™˜๊ฒฝ์—์„œ ๋ชจ๋“  ๊ฒƒ์ด ์ž๋™์œผ๋กœ ์ผ์–ด ๋‚˜๋Š” ๊ทธ๋Ÿฐ ํ™˜๊ฒฝ์ด ๋งž๋Š”๊ฐ€

    Lookalike Targeting on Others\u27 Journeys: Brand Versus Performance Marketing

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    Lookalike targeting is a widely used model-based ad targeting approach that uses a seed database of individuals to identify matching โ€œlookalikesโ€ for targeted customer acquisition. An advertiser has to make two key choices: (1) who to seed on and (2) seed-match rank range. First, we find that seeding on othersโ€™ journey stage can be effective in new customer acquisition; despite the cold start nature of customer acquisition using Lookalike audiences, third parties can indeed identify factors unobserved to the advertiser that move individuals along the journey and can be correlated with the lookalikes. Further, while journey-based seeding adds no incremental value for brand marketing (click-through), seeding on more downstream stages improves performance marketing (donation) outcomes. Second, we evaluate audience expansion strategies by lowering match ranks between the seed and lookalikes to increase acquisition reach. The drop in effectiveness with lower match rank range is much greater for performance marketing than for brand marketing. Performance marketers can alleviate the problem by making the ad targeting explicit, and thus increase perceived relevance; however, it has no incremental impact for higher match lookalikes. Increasing perceived targeting relevance makes acquisition cost comparable for both high and low match ranks

    Lookalike Targeting on Others\u27 Journeys: Brand Versus Performance Marketing

    Get PDF
    Lookalike Targeting is a widely used model-based ad targeting approach that uses a seed database of individuals to identify matching โ€œlookalikesโ€ for targeted customer acquisition. An advertiser has to make two key choices: (1) who to seed on and (2) seed-match rank range. First, we assess if and how seeding by othersโ€™ journey stages impact clickthrough (upstream behavior desirable for brand marketing) and donation (downstream behavior desirable in performance marketing). Overall, we find that lookalike targeting using otherโ€™s journeys can be effective-third parties can indeed identify factors unobserved to the advertiser merely from othersโ€™ journey stage to improve targeting. Further, while it is sufficient to seed on upstream journey stages for brand marketing, seeding on more downstream stages improves performance marketing outcomes. Second, we assess the effectiveness of expanding the target audience with lower match ranks between seed and lookalikes. The drop in effectiveness with lower match rank range is much greater for performance marketing (donation) than for brand marketing (click-through). However, performance marketers can alleviate the reduction in ad effectiveness for low match ranks by making targeting more salient; but increasing salience has little impact for high match rank. Overall, by increasing salience, performance marketers can make acquisition cost comparable for high and low match ranks
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