• 천문학논총
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• 제30권2호
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• pp.593-594
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• 2015

We present our analysis results for an updated orbital ephemeris for the dipping low mass X-ray binary 4U 1624-49, using the light curve collected by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the Monitor of All-Sky X-ray Image (MAXI). To make clear dip profiles, the light curve from the ASM and the MAXI were divided into ten 500d segments and four 400d segments for ASM and MAXI light curves, respectively, and folded with the linear ephemeris proposed by Smale et al. (2001). The phases of dip centers were determined by the method adopted from Hu et al. (2008). The phase drift was then fitted with a linear function. We obtained an updated orbital period of 0.869896(1) d and a phase zero epoch of JD 2450088.6618(57). No clear orbital period derivative is detected with a 2-sigma upper limit of $1.4{\times}10^{-6}(yr)^{-1}$ from a quadratic curve fitting of the dip phase evolution.

• The Korean Journal of Medicine
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• 제93권6호
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• pp.509-517
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• 2018

A small number of viable tuberculosis bacilli can reside in an individual with latent tuberculosis infection (LTBI) without obvious clinical symptoms or abnormal chest radiographs. Diagnosis and treatment of LTBI are important for tuberculosis (TB) control in public and private healthcare facilities, particularly in high-risk populations. The updated 2017 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of them can be used for the diagnosis of LTBI, depending on the age and immune status of the patient as well as their TB contact history. For diagnosis of LTBI, exclusion of active TB is essential, and the possibility of healed TB in those without a history of treatment for TB but at risk of its development must be considered. The treatment options for LTBI include isoniazid, rifampicin, isoniazid/rifampicin, and isoniazid/rifapentine. The benefits and risks of these agents based on the age of the patient and their hepatotoxicity must be considered when selecting the appropriate drug. Standardized diagnosis and treatment of LTBI based on the updated 2017 guidelines will contribute to the control of TB in Korea as well as to further revisions of the guidelines.

• Structural Engineering and Mechanics
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• 제69권3호
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• pp.317-326
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• 2019

This research aims to assess the tight seismic risk curve of the intake tower at Geumgwang reservoir by considering the recorded historical earthquake data in the Korean Peninsula. The seismic fragility, a significant part of risk assessment, is updated by using Bayesian inference to consider the uncertainties and computational efficiency. The reservoir is one of the largest reservoirs in Korea for the supply of agricultural water. The intake tower controls the release of water from the reservoir. The seismic risk assessment of the intake tower plays an important role in the risk management of the reservoir. Site-specific seismic hazard is computed based on the four different seismic source maps of Korea. Probabilistic Seismic Hazard Analysis (PSHA) method is used to estimate the annual exceedance rate of hazard for corresponding Peak Ground Acceleration (PGA). Hazard deaggregation is shown at two customary hazard levels. Multiple dynamic analyses and a nonlinear static pushover analysis are performed for deriving fragility parameters. Thereafter, Bayesian inference with Markov Chain Monte Carlo (MCMC) is used to update the fragility parameters by integrating the results of the analyses. This study proves to reduce the uncertainties associated with fragility and risk curve, and to increase significant statistical and computational efficiency. The range of seismic risk curve of the intake tower is extracted for the reservoir site by considering four different source models and updated fragility function, which can be effectively used for the risk management and mitigation of reservoir.

• Geomechanics and Engineering
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• 제35권1호
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• pp.55-65
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• 2023

Soft clay is widely spread in nature and encountered in geotechnical engineering applications. The creep property of soft clay greatly affects the long-term performance of its upper structures. Therefore, it is vital to establish a reasonable and practical creep constitutive model. In the study, two updated hyperbolic equations based on the volumetric creep and deviatoric creep are respectively proposed. Subsequently, three creep constitutive models based on different creep behavior, i.e., V-model (use volumetric creep equation), D-model (use deviatoric creep equation) and VD-model (use both volumetric and deviatoric creep equations) are developed and compared. From the aspect of prediction accuracy, both V-model and D-model show good agreements with experimental results, while the predictions of the VD-model are smaller than the experimental results. In terms of the parametric sensitivity, D-model and VD-model are lower sensitive to parameter M (the slope of the critical state line) than V-model. Therefore, the D-model which is developed by incorporating the updated deviatoric creep equation is suggested in engineering applications.

• Smart Structures and Systems
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• 제32권6호
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• pp.371-382
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• 2023

Box girder bridges are now widely used in bridge construction, and it is necessary to perform load rating regularly to evaluate the load capacity of box girder bridges. Load testing is a common measure for load rating. However, the bridge must be loaded by many trucks under different loading conditions, which is time-consuming and laborious. To solve this problem, this paper proposes a load rating method for box girder bridges based on rapid moving loads testing. The method includes three steps. First, the quasi-influence factors of the bridge are obtained by crossing the bridge with rapidly moving loads, and the structural modal parameters are simultaneously obtained from the dynamic data to supplement. Second, an objective function is constructed, consisting of the quasi-influence factors at several measurement points and structural modal parameters. The finite element model for load rating is then updated based on the Rosenbrock method. Third, on this basis, a load rating method is proposed using the updated model. The load rating method proposed in this paper can considerably reduce the time duration of traditional static load testing and effectively utilize the dynamic and static properties of box girder bridges to obtain an accurate finite element model. The load capacity obtained based on the updated model can avoid the inconsistency of the evaluation results for the different structural members using the adjustment factors specified in codes.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.736-747
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• 2006

Simultaneous Localization and Map Building(SLAM) is one of the fundamental problems in robot navigation. The Extended Kalman Filter(EKF), which is widely adopted in SLAM approaches, requires extensive computation. The conventional particle filter also needs intense computation to cover a high dimensional state space with particles. This paper proposes an efficient SLAM method based on the recursive unscented Kalman filtering in an environment including a large number of landmarks. The posterior probability distributions of the robot pose and the landmark locations are represented by their marginal Gaussian probability distributions. In particular, the posterior probability distribution of the robot pose is calculated recursively. Each landmark location is updated with the recursively updated robot pose. The proposed method reduces filtering dimensions and computational complexity significantly, and has produced very encouraging results for navigation experiments with noisy multiple simultaneous observations.

• Journal of Computing Science and Engineering
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• 제4권1호
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• pp.53-79
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• 2010

This study proposes a framework to investigate the factors of mobile web success in the context of e-commerce, and the relative importance of these success factors in selecting the most preferred mobile web. First, the Updated Delone and Mclean IS success model (2003) is chosen to extract significant mobile web success factors in the context of e-commerce. Second, it is extended through applying an Analytic Network Process (ANP) approach for investigating the relative importance of each factor and ranking alternative mobile webs in the context of e-commerce. The choice of success measure is a function of the context, which is the objective of this study. Thus, the present study is aimed at evaluating the success of an e-commerce mobile web by customizing measures of the Updated Delone and McLean IS Success model according to the context.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1249-1255
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• 2004

A new parameter adaptation scheme for RBF Neural Network (NN) has been developed in this paper. Even though the RBF Neural Network (NN) based controllers are robust against both un-modeled dynamics and external disturbances, the performance is not satisfactory for a fast and precise mobile robot. To improve the tracking performance as well as robustness, all the parameters of RBF NN are updated in real time. The stability of this control law is rigorously proved by following the Lyapunov stability theory and shown by the experimental simulations. The fact that all of the weighting factors, width and center of RBF NN have been updated implies that this scheme utilizes all the possibilities in RBF NN to make the controller robust and precise while the mobile robot is following un-known trajectories. The performance of this new algorithm has been compared to the conventional RBF NN controller where some of the parameters are adjusted for robustness.

• 한국조리학회지
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• 제23권6호
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• pp.89-98
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• 2017

This research focused on recognizing and empirically testing a relationship between brand personality congruence and brand extension, which can lead to effective marketing strategies for the hotel industry. The objective of this research was to identify how customer's brand personality congruence affect brand extension and to then address what the most appropriate brand extension types for hotel brands are. This study offered a better approach to assess the broader impact of extension strategy for the marketer managers. The methodology for achieving these objectives were described in the following sections: developing measurements based on extensive reviews of literature and analyzing data utilized a exploratory factor analysis and a series of simple linear regression analyses. The result of this study showed customer's brand personality congruence had a great impact on the customer's positive attitude toward core brand. However, customer's attitude toward core brand had no impact on the updated attitude. The findings provided some theoretical and managerial implications for hotel operators.

• 응용통계연구
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• 제10권2호
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• pp.367-374
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• 1997

우리나라 정부나 주요 기관에서 실시하는 표본조사들 중 많은 조사가 패널조사이다. 패널조사에서는 시간의 경과에 따른 모집단구성의 변화를 표본에 적절히 반영해 주어야 하며 이러한 변화를 추정과정에서도 고려하여야 한다. 본 논문에서는 패널조사에서 표본에 일부 변화가 생길 경우 이 변화를 고려하지 않은 일반적인 추정량은 편의를 갖게 되며, 일반적으로 사용하고 있는 추정량의 분산의 식도 적절하지 않음을 보였다. 아울러 표본의 변화를 고려한 불편추정량과 그 분산을 제시하였다.