• Communications for Statistical Applications and Methods
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• v.17 no.5
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• pp.713-724
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• 2010

Calculating or estimating the proper insurance premium is very important decision making process for both the policyholder and the insurance company. The credibility theory is one of the most important theories in actuarial science to get the proper premium. In this research, we introduce the rule of relative exposure volume, the square root rule and the B$\ddot{u}$hlmann credibility, and estimate the new premiums based on these methods. By real data analysis, the accuracy of these credibility methods are compared.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.97-103
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• 2001

Accuracy of a machined part is determined by the relative motion between the cutting tool and the workpiece. One of the important factors which affects the relative motion is the geometric errors of a machine tool. In this study, firstly, geometric errors are measured by laser interferometer, and the positioning error of each control point selected uniformly on the control surface CAD model can be estimated from th oirm shaping model and geometric error data base. Where a form shaping function is derived from the link of homogeneous transformation matrix. Secondly, control points are shifted to the estimated amount of positioning errors. A new control surface is modeled with NURBS(Non Uniform Rational B-Spline) surface approximation to the shifted control points. By generating tool paths to the redesigned control surface, we reduce the machining error quite.

• Journal of Nutrition and Health
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• v.23 no.2
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• pp.93-107
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• 1990

The purposes of this investigation were to determine the validity of various methods (available anthropometric equations and near-infrared light interactance) for estimating body fat and to develop multiple regression equations for the prediction of body fat. Thirty-eight healthy males(age: 20.87$\pm$7.17 yrs) and 12 females(19.58$\pm$2.19 yrs) underwent hydrostatic weighing to determine body fat. Anthropometric measurements were taken of height, weight, nin skinfolds and thirteen circumferences. The results obtained are summarized as follows: 1) Relative body fat determined by underwater weighing was 12.08$\pm$5.21% for the males and 17.97$\pm$5.75% for the females. 2) Circumference and skin fold that had the highest correlation with the body fat were waist girth in males and females(r=0.60, r=0.96, respectively), and subscapular in males(r=0.68) and triceps in females(r=0.96). 3) Corss-validation of 18 selected equations on males revealed total errors ranging from 3.76% to 5.06%. Among these equations, M3(Pollock et al.) demonstrated the least total error. Total error of estimation by near-infrared(NIR) was less than that of available anthropometric measurement equations. The results of the cross-validation of 12 equations on females revealed that F3(Sloan et al.) was clearly superior in accuracy of prediction. 4) Correlational analyses showed that estimation of body fat by NIR measurement seemed to be more closely associated with body fat determined by underwater weighing in women than men, in older subjects than younger ones, and in fatter subjects than leaner ones.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.385-390
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• 2003

Recently, use of Continuous Welded rail(CWR) is increased for structural, economical reason but new problem is caused accordingly and phenomenon that give threat in traveling by ship stability of train is led. According as rail is prolonged, excessive relative displacement and longitudinal force can happen to rail by temperature change and external force. Specially, buckling or fracture of rail can happen in railroad bridges because relative displacement by bridge and properties of matter difference between rail grows and additional axial force happens to rail by behavior of bridge. According to several study, longitudinal force of rail in bridge is influenced with ballast resistance, elongation length, boundary condition, stiffness of framework. Non-linear behavior of ballast acts by the most important factor in interaction between rail and bridge. Therefore, must consider stiffness of bridge construction with non-linear characteristic of ballast and stiffness of base for accuracy with longitudinal force calculation and analyze. In this study, perform material non-linear analysis for longitudinal force of CWR and three dimensional buckling analysis to decide buckling force.

• Structural Engineering and Mechanics
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• v.18 no.6
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• pp.709-729
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• 2004

This paper presents numerical and experimental investigations on damage detection of mono-coupled multistory buildings using natural frequency as only diagnostic parameter. Frequency equation of a mono-coupled multistory building is first derived using the transfer matrix method. Closed-form sensitivity equation is established to relate the relative change in the stiffness of each story to the relative changes in the natural frequencies of the building. Damage detection is then performed using the sensitivity equation with its special features and minimizing the norm of an objective function with an inequality constraint. Numerical and experimental investigations are finally conducted on a mono-coupled 3-story building model as an application of the proposed algorithm, in which the influence of modeling error on the degree of accuracy of damage detection is discussed. A mono-coupled 10-story building is further used to examine the capability of the proposed algorithm against measurement noise and incomplete measured natural frequencies. The results obtained demonstrate that changes in story stiffness can be satisfactorily detected, located, and quantified if all sensitive natural frequencies to damaged stories are available. The proposed damage detection algorithm is not sensitive to measurement noise and modeling error.

• Journal of the Korean Geophysical Society
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• v.4 no.2
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• pp.121-131
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• 2001

We have established 88 auxiliary gravity reference stations by using two gravitimeters at the observation offices of the Korean meteorological agency and measured the locations by using GPS. All gravity values have been calculated on the basis of the gravity reference point at Pusan National University, thus, they have been established to bge easily converted to new absolute gravity value later. The increased numbers of the gravity reference stations will minimize errors due to measurements, drift correction etc. and increase the accuracy of the gravity data. The result of this research will be used to verify the gravity data which calculated with the relative gravity meter and to inspect relative gravity meters.

• Journal of Communications and Networks
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• v.5 no.3
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• pp.187-196
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• 2003

We consider the use of error control coding in direct sequence-code-division multiple access (OS-COMA) systems that employ multiuser detection (MUO) and space diversity. The relative performance gain between Reed-Solomon (RS) code and convolutional code (CC) is well known in [1] for the single user, additive white Gaussian noise (AWGN) channel. In this case, RS codes outperform CC's at high signal-to-noise ratios. We find that this is not the case for the multiuser interference channel mentioned above. For useful error rates, we find that soft-decision CC's to be uniformly better than RS codes when used with DS-COMA modulation in multiuser space-time channels. In our development, we use the Gaussian approximation on the interference to determine performance error bounds for systems with low number of users. Then, we check their accuracy in error rate estimation via system's simulation. These performance bounds will in turn allow us to consider a large number of users where we can estimate the gain in user-capacity due to channel coding. Lastly, the use of turbo codes is considered where it is shown that they offer a coding gain of 2.5 dB relative to soft-decision CC.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.4
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• pp.461-467
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• 2009

Relative positioning technique by GPS that can obtain the high positioning accuracy has been used for generation of high precision positioning with elimination or the reduction of the common errors. This paper gives some algorithms for RTK and considers the filter to estimate the positioning information and integer ambiguities at each epoch in the whole algorithms. The extended kalman filter has been employed to estimate the state parameters and the modified LAMBDA to resolve the integer ambiguities. The data processing was performed by GPS single frequency and dual frequency in short baseline. The verification procedure of these positioning compared with results from Bernese 5.0 software. We presented some statistic values on positioning errors and the rates of integer ambiguity resolution.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.31-34
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• 2010

The rover positioning is performed by estimating the baseline vector components in doubledifference positioning mode. This means that relative displacement due to the tide effects can be neglected when the distance between the reference and rover station is relatively short. However, the tide effects should be carefully modeled and removed as the baseline length gets longer. In this study, the relative displacement over the Korean Peninsula due to tide effects are examined through the numerical analysis. The results show that the tide modeling is required for the precise GPS positioning at cm-level accuracy.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.129-131
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• 2010

This study is to measure 3d deformation of railroad-bridge of steel structure using the non-metric high-resolution digital camera. Measuring the deformation is to be utilized relative orientation using the coplanarity for reduction of the field survey and efficiency of the work. The results are compared with deformation by exterior orientation parameters, which are computed from 3d measurement of control points by the Total-station. Then accuracy of the utilized method will be verified.