• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.460-469
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• 2006

It is widely known that the temperature variation introduces the axial force along a CWR(Continuous Welded Rail) in the railway bridges. Additional axial forces are generated due to many other reasons. These includes the interaction between the bridge girder and the CWR; acceleration or deceleration of the vehicles; support rotation (or deflection) of the girder. Among aforementioned reasons, this study investigates the influence of the support rotation on additional axial forces throughout the numerical study and the field test. Several strains gauges are installed along the CWR and the strains are measured under passing trains. It is expected that the elaborated estimation of the axial force on CWR will be beneficial for future railway maintenance.

• Communications for Statistical Applications and Methods
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• 제22권5호
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• pp.445-462
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• 2015

This article deals with the problem of estimation of the population mean in presence of multi-auxiliary information in two occasion rotation sampling. A multivariate exponential ratio type estimator has been proposed to estimate population mean at current (second) occasion using information on p-additional auxiliary variates which are positively correlated to study variates. The theoretical properties of the proposed estimator are investigated along with the discussion of optimum replacement strategies. The worthiness of proposed estimator has been justified by comparing it to well-known recent estimators that exist in the literature of rotation sampling. Theoretical results are justified through empirical investigations and a detailed study has been done by taking different choices of the correlation coefficients. A simulation study has been conducted to show the practicability of the proposed estimator.

• 한국구조물진단유지관리공학회 논문집
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• 제6권4호
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• pp.219-223
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• 2002

The actual behavior of joint is traditionally disregarded in steel frame design. In fact, the structural analysis of steel frames is generally carried out by assuming that joints fulfil the ideal condition of either a hinge or a fixed-end restraints. In this way, calculations are made somewhat simpler, but the structural model is not able to reflect the actual structural response. Therefore, steel frame classification system for estimation or analysis about behavior of steel frame should be established, and range that each connections belongs should be divided definitely. This research presents realistic and practical moment-rotation relation through investigation and analysis of steel frame beam-to-column classification system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2385-2388
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• 2005

In this paper, we propose the estimation method for the image affine information for computer vision. The first estimation method is given based on the XYS image normalization and the second estimation method is based on the image normalization by Pei and Lin. The XYS normalization method turns out to have better performance than the method by Pei and Lin. In addition, we show that rotation and aspect ratio information can be obtained using the central moments of both the original image and the sensed image. Finally, we propose the modified version of the normalization method so that we may control the size of the image.

• Journal of Information Processing Systems
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• 제18권3호
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• pp.293-301
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• 2022

Direction of arrival (DOA) estimation of space signals is a basic problem in array signal processing. DOA estimation based on the multiple signal classification (MUSIC) algorithm can theoretically overcome the Rayleigh limit and achieve super resolution. However, owing to its inadequate real-time performance and accuracy in practical engineering applications, its applications are limited. To address this problem, in this study, a DOA estimation algorithm with high parallelism and precision based on an analysis of the characteristics of complex matrix eigenvalue decomposition and the coordinate rotation digital computer (CORDIC) algorithm is proposed. For parallel and single precision, floating-point numbers are used to construct an orthogonal identity matrix. Thus, the efficiency and accuracy of the algorithm are guaranteed. Furthermore, the accuracy and computation of the fixed-point algorithm, double-precision floating-point algorithm, and proposed algorithm are compared. Without increasing complexity, the proposed algorithm can achieve remarkably higher accuracy and efficiency than the fixed-point algorithm and double-precision floating-point calculations, respectively.

• 전자공학회논문지B
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• 제31B권12호
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• pp.59-71
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• 1994

This paper proposes a motion estimation method in video sequences based on the feature based matching and anistropic propagation. It measures translation and rotation parameters using a relaxation scheme at feature points and object orinted anistropic propagation in continuous and discontinuous regions. Also an iterative improvement motion extimation based on the strongly coupled module fusion and adaptive smoothing is proposed. Computer simulation results show the effectiveness of the proposed algorithm.

• The Journal of Korean Physical Therapy
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• 제24권5호
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• pp.334-339
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• 2012

Purpose: This study was conducted in order to compare the ability to control postural sway during perturbation when stroke patients received postural sway induced by head rotation. Methods: This study included 15 stroke patients and 15 healthy adults. Each group was measured by 3D motion analysis for determination of the angle of the neck in static position and by balance performance monitor for estimation of swaying angle in both neutral posture and head rotation position. These results were then analyzed in order to compare the healthy control group and the stroke patients group. Results: In both static posture ($60.7{\pm}4.81$) and dynamic posture ($51.46{\pm}6.87$, $70.8{\pm}6.55$), significant decreases were observed in the angle of head rotation of the patient group, compared to the healthy group (p<0.05), and significant decreases were observed in the sway angle of the patient group when in the neutral position ($3.62{\pm}7$, $24{\pm}0.60$) and head rotation ($3.04{\pm}0.80$, $51.46{\pm}6.87$), compared to the healthy group (p<0.05). Conclusion: According to these findings, patients with stroke tend to restrict the ROM of head rotation and swaying angle in dynamic posture and maintain their posture instability using limitation of head movement relative to the trunk and sway angle of area which is larger than that of affected side in unaffected side.

• 아태비즈니스연구
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• 제12권4호
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• pp.193-209
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• 2021

Purpose - The purpose of this study is to specify the relationship between demographic cohesion and firm performance by examining the roles of HR practices, such as job rotation and flexible work arrangement. Design/methodology/approach - This study samples 1,093 firms in Korea and collects their data between 2007 and 2017 from Workplace Panel Survey, a database from Korea Labor Institute. The demographic cohesion is measured using the Herphindal-Hershman index and the firm performance is measured with net incomes. This study employs a fixed-effects model for the estimation of firm performance with respect to demographic cohesion, job rotation, and flexible work arrangement. Findings - There is a positive relationship between demographic cohesion and net incomes. And the relationship is positively moderated by job rotation. However, flexible work arrangement shows a mixed moderation. Research implications or Originality - Differentiated from the studies on demographic diversity, this study shows that demographic cohesion has a mixed impact on firm performance. While demographic cohesion can improve firm performance through trust building, in-group favoritism, and collective identity it entails internal conflicts. However the link between demographic cohesion and firm performance is moderated by job rotation and flexible work arrangement. While there is a positive moderation of job rotation, there is a negative moderation of flexible work arrangement.

• Steel and Composite Structures
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• 제18권4호
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• pp.873-887
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• 2015

The continuous composite I-girder should have a sufficient rotation capacity (or ductility) to redistribute the negative bending moment into an adjacent positive bending moment region. However, it is generally known that the ductility of the high strength steel is smaller than that of conventional steel, and application of high strength steel can cause ductility problems in a negative moment region of the I-girder. In this study, moment redistribution of the continuous composite I-girder with high strength steel was studied, where high strength steel with yield stress of 690 MPa was considered (the ultimate stress of the steel was 800 MPa). The available and required rotation capacity of the continuous composite I-girder with high strength steel was firstly derived based on the stress-strain curve of high strength steel and plastic analysis, respectively. A large scale test and a series of non-linear finite element analysis for the continuous composite I-girder with high strength steel were then conducted to examine the effectiveness of proposed models and to investigate the effect of high strength steel on the inelastic behavior of the negative bending moment region of the continuous composite I-girder with high strength steel. Finally, it can be found that the proposed equations provided good estimation of the requited and available rotation capacity of the continuous composite I-girder with high strength steel.

• Structural Engineering and Mechanics
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• 제87권1호
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• pp.19-28
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• 2023

This paper describes the experimental investigation of steel pallet rack beam-to-column connec-tions. Total behavior of moment-rotation (M-φ) curve and the effect of particular characteristics on the behavior of connection were studied and the associated load strain relationship and corre-sponding failure modes are presented. In this respect, an estimation of SPRBCCs moment and rotation are highly recommended in early stages of design and construction. In this study, a new approach based on Support Vector Machines (SVMs) coupled with discrete wavelet transform (DWT) is designed and adapted to estimate SPRBCCs moment and rotation according to four input parameters (column thickness, depth of connector and load, beam depth,). Results of SVM-WAVELET model was compared with genetic programming (GP) and artificial neural networks (ANNs) models. Following the results, SVM-WAVELET algorithm is helpful in order to enhance the accuracy compared to GP and ANN. It was conclusively observed that application of SVM-WAVELET is especially promising as an alternative approach to estimate the SPRBCCs moment and rotation.