• Communications for Statistical Applications and Methods
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• 제16권3호
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• pp.519-528
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• 2009

This paper deals with nonparametric estimation of discontinuous regression curve. Quite number of researches about this topic have been done. These researches are classified into two categories, the indirect approach and direct approach. The major goal of the indirect approach is to obtain good estimates of jump locations, whereas the major goal of the direct approach is to obtain overall good estimate of the regression curve. Thus it seems that two approaches are quite different in nature, so people say that the comparison of two approaches does not make much sense. Therefore, a thorough comparison of them is lacking. However, even though the main issue of the indirect approach is the estimation of jump locations, it is too obvious that we have an estimate of regression curve as the subsidiary result. The point is whether the subsidiary result of the indirect approach is as good as the main result of the direct approach. The performance of two approaches is compared through a simulation study and it turns out that the indirect approach is a very competitive tool for estimating discontinuous regression curve itself.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.562-568
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• 2020

This study investigates the relationship between ultrasonic velocity and density in the direct method, the effect of distance between transducers in the indirect method, and the difference between the direct and indirect methods with transducers placed at a distance of 200 mm in nondestructive ultrasonic testing of spruce lumber. The direct method using 54 kHz ultrasonic transducers was applied to two planes, namely, radial section (LR) and tangential section (LT) of samples. The indirect method measurements were taken using the same transducers. Two velocities were measured at the top and bottom of the LT plane and at the two sides of the LR plane; the two values for each plane were averaged. The relationship between density and ultrasound velocity in the direct method demonstrated a positive correlation between the two variables. The difference between the two planes, LT and LR, was not statistically significant. Moreover, the distance between the transducers in the indirect method affected ultrasound velocity, with the ultrasonic velocity increasing as the distance between the transducers became larger. A transducer distance of 200 mm yielded a close approximation of the direct method results with a ratio of 0.87. Finally, no statistical evidence of a difference between the two planes in the indirect method was found. If the direct method, which requires access to two surfaces, is impractical, the indirect method can be applied.

• 기본간호학회지
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• 제8권3호
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• pp.366-378
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• 2001

Objective: The purpose of this study was to identify differences in measurement methods for blood pressure (Direct measurement, HP automatic indirect measurement, and SE 7000 Korean made indirect measurement), and to evaluate the clinical trial of the Korean made automatic indirect blood pressure measurement. Material & Methods: From June, 1999 to February, 2000, fifty five consecutive patients were randomized into hypertension group (n=20), normotension group (n=20), and hypotension group (n= 15). Measuring blood pressure by indirect methods (HP NIBP M 1008B and SE 7000 NIBP Korean made) was done simultaneously in the same arm with arterial line for direct blood pressure measurement (HP M1006A). The procedures were repeated ten times at intervals of 2 minutes. Statistical analysis was Performed using SPSS (version 8.0 for windows) software package. Values were expressed as means and standard deviation and means were compared using t-test. Statistical significance was considered present with a p value less than 0.05. Results: In the hypertension group and noromotension group, the disparity between HP direct measurement and indirect SE 7000 NIBP did not show any differences compared to the disparity between HP direct measurement and indirect HP NIBP. In the hypotension group, the disparity in the diastolic pressure between HP direct measurement and indirect SE 7000 NIBP was significantly different compared to the disparity between HP direct measurement and indirect HP NIBP (p<0.001), however, disparities in systolic pressure did not showed any differences. Conclusion: Direct blood pressure measurement (HP M1006A) can be replaced with indirect blood pressure measurements (HP NIBP M 1008B & SE 7000 NIBP) in normotension and hypertension patients. Korean made indirect measurement was found to be more accurate compared to HP indirect measurement in hypotension Patients, but more study is needed.

• Journal of Preventive Medicine and Public Health
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• 제56권4호
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• pp.303-311
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• 2023

Traditional mediation analysis, which relies on linear regression models, has faced criticism due to its limited suitability for cases involving different types of variables and complex covariates, such as interactions. This can result in unclear definitions of direct and indirect effects. As an alternative, causal mediation analysis using the counterfactual framework has been introduced to provide clearer definitions of direct and indirect effects while allowing for more flexible modeling methods. However, the conceptual understanding of this approach based on the counterfactual framework remains challenging for applied researchers. To address this issue, the present article was written to highlight and illustrate the definitions of causal estimands, including controlled direct effect, natural direct effect, and natural indirect effect, based on the key concept of nested counterfactuals. Furthermore, we recommend using 2 R packages, 'medflex' and 'mediation', to perform causal mediation analysis and provide public health examples. The article also offers caveats and guidelines for accurate interpretation of the results.

• 한국물환경학회지
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• 제26권6호
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• pp.963-968
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• 2010

This study has carried out to evaluate the performance of direct and indirect oxidation electrode for the purpose of decolorization of Rhodamine B (RhB) in water. Four kinds of electrodes were used for comparison: Pt and JP202 (indirect oxidation electrode), Pb and boron doping diamond (BDD, direct oxidation electrode). The effect of applied current (0.5 ~ 2.5 A), electrolyte type (NaCl, KCl, HCl, $Na_2SO_4$ and $H_2SO_4$) and electrolyte concentration (0.5 ~ 2.5 g/L), solution pH (3 ~ 11) and initial RhB concentration (25 ~ 125 mg/L) were evaluated. Experimental results showed that RhB removal efficiency were increased with increase of current, NaCl dosage and decrease of the pH. However, the effect of operating parameter on the RhB removal were different with the electrode type. JP202 electrode was the best electrode from the point of view of performance and energy consumption. The order of removed RhB concentration per energy lie in: JP202>Pt>Pb>BDD.

• Journal of Welding and Joining
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• 제29권4호
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• pp.93-99
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• 2011

This study was performed to compare the shear strength of the bondings between stainless steel crown/direct type composite resin and stainless steel crown/indirect type composite resin. Four groups of bonding conditions were prepared. Two groups of bonding conditions were made by the indirect type composite resin system and the other two groups were made by the direct type composite resin system. The shear strength tests were carried out using universal testing machine, Model 4465 of Instron Co.. It was indicated that the bond strength values of the indirect type composite resins were higher than those of the direct type composite resins. TE-SE group was superior to the TE-ONE in indirect type resin system. These results were thought to be the high degree of the polymerization accompanied with temperature and pressure of the resin of indirect type resin. It was also found that indirect composite resin contains less amount of porosity in resin.

• 응용통계연구
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• 제23권6호
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• pp.1245-1253
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• 2010

There are two main approaches for estimating the discontinuous regression function nonparametrically. One is the direct approach, the other is the indirect approach. The major goal of the two approaches are different. The direct approach focuses on the overall good estimation of the regression function itself, whereas the indirect approach focuses on the good estimation of jump locations. Apparently, the two approaches are quite different in nature. Gijbels et al. (2007) argue that the comparison of two approaches does not make much sense and that it is even difficult to choose an appropriate criterion for comparisons. However, it is obvious that the indirect approach also has the regression curve estimate as the subsidiary result. Therefore it is necessary to verify the appropriateness of the indirect approach as the estimator of the discontinuous regression function itself. Park (2009a) compared the performance of two approaches through a simulation study. In this paper, we consider a more general case and draw some useful conclusions.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.656-660
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• 2004

The Mobile Mapping System is an effective method to acquire the position and image data using vehicle equipped with the GPS (Global Positioning System), IMU (Inertial Measurement Unit), and CCD camera. It is used in various fields of road facility management, map update, and etc. In the general photogrammetry such as aerial photogrammetry, GCP (Ground Control Point)s are needed to compute the image exterior orientation elements (the position and attitude of camera). These points are measured by field survey at the time of data acquisition. But it costs much time and money. Moreover, it is not possible to make sufficient GCP as much as we want. However Mobile Mapping System is more efficient both in time and money because it can obtain the position and attitude of camera at the time of photographing. That is, Indirect Georeferencing must use GCP to compute the image exterior orientation elements, but on the other hand Direct Georeferencing can directly compute the image exterior orientation elements by GPS/INS. In this paper, we analyze about the positional accuracy comparison of ground point using the Direct Georeferencing and Indirect Georeferencing.

• Physical Therapy Rehabilitation Science
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• 제12권2호
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• pp.201-205
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• 2023

Objective: Resistance exercise is a necessary element to improve quality of life, and measurement and evaluation of muscle strength provide important information for prescription and management of rehabilitation and exercise programs. This study analyzed the correlation between direct and indirect 1RM for isokinetic maximum torque of the knee joint in order to provide useful information in the field of exercise programs. In addition, the flexion-extension ratio and the difference in left-right deviation were verified. Design: A cross-sectional study Methods: The subjects of this study were 33 healthy adult men and women without medical problems who participated in the health exercise class program at S University in Seoul. The correlation between isokinetic maximum torque and direct and indirect 1RM was analyzed, and a dependent t-test was performed to analyze the flexion-extension ratio and left-right deviation. Results: There was a high correlation between the isokinetic maximum torque and direct and indirect 1RM, and no statistically significant difference was shown between the test methods in the analysis of the flexion-extension ratio and left-right deviation. Conclusions: Isokinetic muscle function measuring equipment is expensive, so it is difficult to use it in local exercise rehabilitation and training sites. Through this study, it was found that direct and indirect 1RM isokinetic maximum torque showed a high correlation, and there was no difference in evaluating muscle function such as flexion-extension ratio and left-right deviation. Therefore, it is considered that the muscle function evaluation using 1RM in general field can be usefully utilized.

• 한국안전학회지
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• 제16권3호
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• pp.111-116
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• 2001

This study is conducted to review the ratio of direct and indirect cost accompanied by industrial accident in construction sites. It is surveyed that how to use safety cost in construction work is most efficient in comparison with several items of safety cost through the regression analysis.