• Title/Summary/Keyword: robust estimation

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Fast Noise Reduction Approach in Multifocal Multiphoton Microscopy Based on Monte-Carlo Simulation

  • Kim, Dongmok;Shin, Younghoon;Kwon, Hyuk-Sang
    • Current Optics and Photonics
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    • v.5 no.4
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    • pp.421-430
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    • 2021
  • The multifocal multiphoton microscopy (MMM) enables high-speed imaging by the concurrent scanning and detection of multiple foci generated by lenslet array or diffractive optical element. The MMM system mainly suffers from crosstalk generated by scattered emission photons that form ghost images among adjacent channels. The ghost image which is a duplicate of the image acquired in sub-images significantly degrades overall image quality. To eliminate the ghost image, the photon reassignment method was established using maximum likelihood estimation. However, this post-processing method generally takes a longer time than image acquisition. In this regard, we propose a novel strategy for rapid noise reduction in the MMM system based upon Monte-Carlo (MC) simulation. Ballistic signal, scattering signal, and scattering noise of each channel are quantified in terms of photon distribution launched in tissue model based on MC simulation. From the analysis of photon distribution, we successfully eliminated the ghost images in the MMM sub-images. If the priori MC simulation under a certain optical condition is established at once, our simple, but robust post-processing technique will continuously provide the noise-reduced images, while significantly reducing the computational cost.

Robust Object Pose Estimation for Dynamic Projection Mapping (동적 프로젝션 맵핑을 위한 안정적 객체 자세 추정)

  • Kim, Sang-Joon;Byun, Young-Ju;Choi, Yoo-Joo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2018.06a
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    • pp.105-106
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    • 2018
  • 본 논문에서는 동적 프로젝션 맵핑을 구현하기 위하여 3차원 공간의 깊이 정보와 대상 객체의 색상영상에서의 특징점을 추출하여 3차원 공간상에서 움직이는 2차원 평면 객체의 자세를 안정적으로 추정하는 기법을 제안한다. 제안 기법은 타겟 이미지를 출력하여 타겟 이미지 보다 큰 평면 패널에 부착하고, 이 평면 패널을 3차원 공간상에서 움직이는 환경에서 타겟 이미지의 자세를 안정적으로 추정하기 위하여 고안되었다. 제안 기법에서는 우선 패널이 움직일 수 있는 깊이 영역을 지정하여 해당 깊이 영역에 존재하는 2차원 패널을 추출하고, 패널의 사각영역을 추출한다. 또한, 색상 영상에 SURF 알고리즘을 적용하여 2차원 평면상에 부착된 타겟 이미지의 영역을 색상 특징을 기반으로 함께 추출하여 패널의 사각 영역과 타겟 이미지의 상대적인 위치 정보를 추출한다. 셋업 단계에서 추출된 타겟 이미지의 상대적인 위치 정보를 이용하여, 조명의 변화에 의하여 순간적으로 타겟 이미지의 특징점 추적에 실패한 경우, 패널의 사각 영역에 의해 계산된 타겟 이미지의 상대적 위치 정보를 계산하여 자세 추정에 사용함으로써 움직이는 타겟 이미지의 3차원 자세를 안정적으로 추정할 수 있도록 하였다.

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Education, Industry 4.0 and Earnings: Evidence from Provincial-Level Data of Vietnam

  • TU, Anh Thuy;CHU, Phuong Thi Mai;PHAM, Truong Xuan;DO, Ngoc Minh
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.675-684
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    • 2021
  • This paper aims to analyze factors influencing earnings of workers in Vietnam using provincial-level data from 2016 to 2018. We show the important determinants of earnings of workers of more than 15 years old including working hour, labor force, life expectancy, education, regulation measured by Provincial Competitiveness Index (PCI) and especially Industry 4.0, our major depart from literature proxies by government expenditure on science and technology, number of phone lines, and number of internet users. Working hours are a typical measurement of quantity of labor supplied. Labor force represents market size from the supply side. Life expectancy measures the health of laborers, a physical quality measure of workers. PCI stands for institutional status of the locality. Two most important factors of our interest are education, representing qualification of workers, and Industry 4.0, reflecting the new working environment of workers. By estimating a robust standard error fixed-effect model, we have evidence that all factors are significant in explaining earnings of Vietnamese workers. Education and IR4.0 play an important role in earnings of workers of Vietnam. Results also provide an estimation of Vietnam's labor supply in the context of Industry 4.0. In addition, findings contribute to explain the income discrepancy among Vietnamese provinces.

A New Measurement and Its Determinants for Corporate Environmental Management: An Empirical Study in Vietnam

  • TU, Anh Thuy;CHU, Phuong Thi Mai
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.8
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    • pp.487-496
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    • 2021
  • This study examines the environmental performance of firms in Vietnam and its determinants. The contribution of the paper is on both theoretical and empirical aspects. On the theoretical matter, the research proposes a new index measuring environmental management at the firm level, namely the Environmental Management Index with a clear illustration for the case of Vietnam. On the empirical matter, the study points out and estimates determinants of the corporate environmental performance of Vietnamese firms measured by the newly proposed index. Due to data availability and the impossibility of getting more updated data, the empirical analysis covers only the period from 2004-2009. However, findings are still meaningful because, on the one hand, it provides some evidence for Vietnamese policymakers; on the other hand, with the robust methodology proposed, when more recent data are available, researchers can easily replicate the estimation for more insights. Empirical results show that factors having positive impacts on the environmental performance of Vietnamese firms are profit, capital stock, and interestingly public pressure proxied by the population of the province where the firm is located. Firm ownership does also matter in explaining the corporate environmental performance of Vietnam.

Finite-time Adaptive Non-singular Terminal Sliding-mode Control for Robot Manipulator (로봇 매니퓰레이터에 적용을 위한 유한한 시간 적응 비특이 터미널 슬라이딩 모드 제어 기법)

  • Baek, Jae-Min;Yun, Kyeong-Soo;Kang, Min-Seok
    • IEMEK Journal of Embedded Systems and Applications
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    • v.16 no.4
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    • pp.137-143
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    • 2021
  • We propose an adaptive non-singular terminal sliding-mode control for the fast finite-time convergence (FANTSMC) in robot manipulator. The proposed FANTSMC approach is developed to be applied without singularity in robot manipulator, which has a new pole-placement control with the non-singular terminal sliding variable while generating the desirable control torque. Moreover, the switching gain is designed to suppress the time-delayed estimation error appropriately, which aims at providing the high robust tracking performance. Also, the proposed one employs one-sample delayed information to cancel out the system uncertainties and disturbances. For these reasons, it offers strong attraction within the finite time. It is shown that the tracking performance of the proposed FANTSMC approach is guaranteed to be uniformly ultimately bounded through the Lyapunov stability. The effectiveness of the proposed FANTSMC approach is illustrated in simulations, which is compared with that of the up-to-date control approach.

FDI Spillover Effects on the Productivity of the Indian Pharmaceutical Industry: Panel Data Evidence

  • DESAI, Guruprasad;SRINIVASAN, Palamalai;GOWDA, Anil B
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.8
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    • pp.109-121
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    • 2022
  • The study empirically examines the horizontal spillover effects of foreign direct investment (FDI) on the productivity of Indian pharmaceutical firms. Robust least squares and the Generalized Method of Moments estimators are applied for the firm-level panel data of Indian pharmaceutical companies whose shares were traded on the National Stock Exchange (NSE) and Bombay Stock Exchange (BSE). The information was collected from the Centre for Monitoring Indian Economy (CMIE) Prowess database from 2015 to 2019. Based on the regularity in data availability, the sample firms are limited to 112 companies, 100 of which are domestic firms and 12 international firms. Firms with more than 10 percent foreign equity are classified as FDI firms, while those with less than that are classified as domestic firms. Estimation results show that foreign ownership does not contribute to the productivity of domestic firms. Due to increased competition, the Indian pharmaceutical companies with foreign equity participation are not more productive than local ones. Moreover, the findings reveal a negative and insignificant horizontal spillover effect from FDI on the productivity of domestic enterprises. The absence of horizontal spillovers may be attributable to foreign enterprises' ability to prevent technological outflow to competitors in the same industry.

Linking nuclear energy, human development and carbon emission in BRICS region: Do external debt and financial globalization protect the environment?

  • Sadiq, Muhammad;Shinwari, Riazullah;Usman, Muhammad;Ozturk, Ilhan;Maghyereh, Aktham Issa
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3299-3309
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    • 2022
  • Nuclear energy has the potential to play an influential role in energy transition efforts than is now anticipated by many countries. Realizing sustainable human development and reducing global climate crises will become more difficult without significantly increasing nuclear power. This paper aims to probe the role of nuclear energy, external debt, and financial globalization in sustaining human development and environmental conditions simultaneously in BRICS (Brazil, Russia, India, China, and South Africa) countries. This study applied a battery of second-generation estimation approaches over the period from 1990 to 2019. These methods are useful and robust to cross-countries dependencies, slope heterogeneity, parameters endogeneity, and serial correlation that are ignored in conventional approaches to generate more comprehensive and reliable estimates. The empirical findings indicate that nuclear energy and financial globalization contribute to human development, whereas external debt inhibits it. Similarly, financial globalization accelerates ecological deterioration, but nuclear energy and external debt promote environmental sustainability. Moreover, the study reveals bidirectional feedback causalities between human development, carbon emissions and nuclear energy consumption. The study offers useful policy guidance on accomplishing sustainable and inclusive development in BRICS countries.

Structural health monitoring for pinching structures via hysteretic mechanics models

  • Rabiepour, Mohammad;Zhou, Cong;Chase, James G.;Rodgers, Geoffrey W.;Xu, Chao
    • Structural Engineering and Mechanics
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    • v.82 no.2
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    • pp.245-258
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    • 2022
  • Many Structural Health Monitoring (SHM) methods have been proposed for structural damage diagnosis and prognosis. However, SHM for pinched hysteretic structures can be problematic due to the high level of nonlinearity. The model-free hysteresis loop analysis (HLA) has displayed notable robustness and accuracy in identifying damage for full-scaled and scaled test buildings. In this paper, the performance of HLA is compared with seven other SHM methods in identifying lateral elastic stiffness for a six-story numerical building with highly nonlinear pinching behavior. Two successive earthquakes are employed to compare the accuracy and consistency of methods within and between events. Robustness is assessed across sampling rates 50-1000 Hz in noise-free condition and then assessed with 10% root mean square (RMS) noise added to responses at 250 Hz sampling rate. Results confirm HLA is the most robust method to sampling rate and noise. HLA preserves high accuracy even when the sampling rate drops to 50 Hz, where the performance of other methods deteriorates considerably. In noisy conditions, the maximum absolute estimation error is less than 4% for HLA. The overall results show HLA has high robustness and accuracy for an extremely nonlinear, but realistic case compared to a range of leading and recent model-based and model-free methods.

Effect of Social Norm on Consumer Demand: Multiple Constraint Approach

  • Choi, Sungjee;Nam, Inwoo;Kim, Jaehwan
    • Asia Marketing Journal
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    • v.22 no.1
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    • pp.41-60
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    • 2020
  • The goal of the study is to understand the role of social norm in purchase decisions where demand is revealed in the form of multiple-discreteness. Consumers are socially engaged in various activities through the expectation from others in their community. Actions or decisions are likely to reflect this influence. This implicit or explicit social norm is revealed as the rules, regulations, and standards that are understood, shared, endorsed, and expected by group members. When consumers' decisions are in distance from the norm, they come to face discomfort such as shame, guilt, embarrassment, and anxiety. These pressure act as a constraint as opposed to utility in their decision making. In this study, the effect of social norms on consumer demand is captured via multiple constraint model where constraints are not only from budget equation but also from psychological burden induced by the deviation from the norm. The posterior distributions of model parameters were estimated via conjoint study allowing for heterogeneity via hierarchical Bayesian framework. Individual characteristics such as age, gender and work experience are also used as covariates for capturing the observed heterogeneity. The empirical results show the role of social norm as constraint in consumers' utility maximization. The proposed model accounting for social constraint outperforms the standard budget constraint-only model in terms of model fit. It is found that people with longer job experience tend to be more robust and resistant to the deviation from the norm. Incorporating social norm into the utility model allows for another means to disentangle the reason for no-purchase as 'not preferred' and 'not able to buy'.

SIMULTANEOUS FAULT DETECTION AND CONTROL OF LINEAR TIME-INVARIANT SYSTEM VIA DISTURBANCE OBSERVER-BASED CONTROL APPROACH

  • PANG, GUOCHEN;JIAO, YU;ZHANG, HONGZI;CHEN, XIANGYONG;ZHANG, ANCAI;QIU, JIANLONG
    • Journal of applied mathematics & informatics
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    • v.40 no.1_2
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    • pp.47-59
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    • 2022
  • This paper concerns the problem of simultaneous fault detection and disturbance reject control(SFDDRC) for a class of linear time-invariant system. In the framework of fault detection, residual generators are required to be robust to disturbances existing in the system. Different from most of the existing simultaneous fault and control(SFDC) methods, SFDDRC rejects the influences of disturbances on residual generators by disturbance observer-based control(DOBC). This not only effectively improves the accuracy of fault detection, but also solves the problem that most of the existing SFDC methods require that the disturbance must be bounded. Finally, a numerical example is given to verify the validity of the method.