• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.891-897
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• 1994

A method has been investigated for the determination of Selenium in Ginseng radix, Ganoderma Lucidum and Garlic using hydride generation atomic absorption spectrometry (HG-AAS). The effects of several acids and sodium tetrahydroborate concentration and their flow rate on the determination of Selenium for the hydride generation were investigated. The method of sample decomposition was also investigated using various mineral acids, such as nitric, perchloric and sulfuric acid in the closed system and foreign ion effects were studied. In the optimum conditions, we obtained calibration curve in the range 0-40 ppb. The analytical data of Garlic, Ganoderma Lucidum and Ginseng radix are 289, 296, 198 ppb, respectively.

• Physical Therapy Korea
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• v.23 no.2
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• pp.35-43
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• 2016

Background: The Functional Gait Assessment (FGA) was developed to measure of gait-related activities. The FGA was translated in Korean but only a few psychometric characteristics had been studied. Objects: The purpose of this study was to evaluate the validity and reliability of the Korean version of FGA scale using Rasch analysis. Methods: The study included 120 patients with stroke (age range=30~83 years; mean${\pm}$standard deviation=$58.3{\pm}11.1$). The FGA and Berg Balance Scale were performed, and were analysed for dimensionality of the scale, item difficulty, scale reliability and separation, and item-person map using Rasch analysis. Results: The 4 rating scale categories of FGA were satisfied with optimal rating scale criteria. The most items of the FGA showed sound item psychometric properties except 2 items ('gait with the horizontal head turns', and 'gait with narrow base of support'), and the 2 misfit items were excluded for all further analyses. The 8 items were arranged in order of difficulty. The most difficult item was 'gait with eyes closed', the middle difficult item was 'gait level surface', and the easiest item was 'gait with vertical head turns.' A person separation reliability was .93 and the person separation index was 3.57. Conclusion: This study suggests that the 8-item Korean FGA are valid measure of assess the gait-related balance performance, and to set the goal of rehabilitation plan in patient with stroke.

• ETRI Journal
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• v.35 no.5
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• pp.827-837
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• 2013

In this paper, we present wideband common-mode (CM) noise suppression using a vertical stepped impedance electromagnetic bandgap (VSI-EBG) structure for high-speed differential signals in multilayer printed circuit boards. This technique is an original design that enables us to apply the VSI-EBG structure to differential signals without sacrificing the differential characteristics. In addition, the analytical dispersion equations for the bandgap prediction of the CM propagation in the VSIEBG structure are extracted, and the closed-form expressions for the bandgap cutoff frequencies are derived. Based on the dispersion equations, the effects of the impedance ratio, the EBG patch length, and via inductances on the bandgap of the VSI-EBG structure for differential signals are thoroughly examined. The proposed dispersion equations are verified through agreement with the full-wave simulation results. It is experimentally demonstrated that the proposed VSI-EBG structure for differential signaling suppresses the CM noise in the wideband frequency range without degrading the differential characteristics.

• Journal of Forest and Environmental Science
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• v.25 no.2
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• pp.85-91
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• 2009

About 83% of the total population of Lao PDR lives in rural areas. People living near forest are highly dependent on the forest resources closed to their villages. Especially non-timber forest products (NTFPs) provide a wide range of subsistence needs and are the main source of their cash income. They also make a significant contribution to the country economy. The annual export value of NTFPs is considerably high. 708 edible NTFP species (238 edible plants and 470 animals) have been recorded so far, and about 400 plants have been reported and used as medicinal plants by Lao people. One hundred NTFP species are considered as commercial forest products. The striking trend in NTFP resources is the decline of some commercial species due to increased demand on them for commercialization, and the loss of forest by rapid population growth. To sustainablely manage the NTFPs resources, a number of new management systems are under development and support in progress by the government.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.397-400
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• 1996

In this paper, robust motion control of a flexible micro-actuator is presented. The actuator is made of a bimorph piezoelectric high-polymer material (PVDF). No mathematical model system can exactly model a physical system such a flexible micro-actuator. For this reason we must be aware of how modeling errors might adversely affect the performance of a control system for such a model. The H method addresses a wide range of the control problems, combining the frequency and time domain approaches. The design is an optimal one in the sense of minimization of the maximum of the closed-loop transfer function. It includes colored measurement and process noise. It also addresses the issues of robustness due to model uncertainties, and is applicable to the, flexible micro-actuator control problem. Therefore, we adopt the H control problem to the robust motion control of the flexible micro-actuator. Theoretical and experimental results demonstrate the satisfactory performance and the effectiveness of the designed controller. the effectiveness of the designed controller.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.1
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• pp.95-100
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• 2005

This paper proposes a DVS method which effectively reduces the power consumption of multimedia signal processor. Analytic derivations of effective range of its power saving factor are obtained with the assumption of a Gaussian distribution for the frame-based computational burden of the multimedia processor. A closed form equation of the power saving factor is derived in terms of the mean-standard deviation of the distribution. An MPEG-2 video decoder algorithm and AAC encoder algorithm are tested on ARM9 RISC processor for the experimental verification of the power saying of the proposed DVS approach. The experimental results with diverse MPEG-2 video and audio files show 50～30% power saving factor and show good agreement with those of the analytically derived values.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.12
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• pp.1267-1271
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• 2014

There have been many autonomous robot calibration methods which form closed loop structures through the various attached sensors and mechanical fixtures. Single point calibration among them has been used for on-site calibration due to its convenience of implementation. The robot can reach a single point with infinitely many configurations so that single point calibration algorithm can be set up and easily implemented relative to the other methods. However, it is not still easy to drive the robots' sharp edge to its corresponding edge of the fixture. This is error-prone process. In this paper, we propose a 3 dimensional small displacement measuring sensor and a robot calibration algorithm based on this sensor. This method relieves the difficulty of matching two edges in the single point calibration and improves the resulting robot accuracy. Simulated study is carried out on a Hyundai HA06 robot to show the effectiveness of the proposed method over the single point calibration. And also, the resulting robot accuracy is compared with that from 3D laser tracker based calibration to show the dependency of robot accuracy on range of the workspace where the measurement data are collected.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.425-432
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• 2001

Single-phase heat transfer coefficients and pressure drops of R-22 were measured in smooth, horizontal copper tubes with inner diameters of 3.36 mm, 5.35 mm, 6.54 mm and 8.12 mm, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables: Reynolds from 1000 to 20000. Single-phase heat transfer coefficients increased by $10{\sim}30%$ as the inner diameter of tube was reduced and it was found that a well-known previous correlation, Gnielinski's correlation, was not suitable for the small diameter tubes. But the pressure drop in the small diameter tubes have been shown slightly deviations with Blauius' correlation. Based on an analogy between heat and mass transfer, the new heat transfer correlation is proposed to predict the experimental data successfully.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.595-600
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• 2001

Thermal mass flow meter(TMF) and thermal mass flow controller(MFC) were used to measure and to control the mass flow rate of gases. TMF and MFC were designed for specified working pressure and gas. For the case of different working pressure and gases, the flow rate measurement accuracy decreased dramatically. In this study, a TMF and MFC was tested with three different gases and pressure range from 0.2 MPa up to 1.0 MPa. Effect of specific heat causes to increase flow measurement error as much as ratio of specific heat compared with reference gas. Changing of pressure causes to increase flow rate measurement error about -0.2% as the working pressure decreased 0.1 MPa. Response time of MFC was below 3.12 s for the case of increasing of flow rate. But the response time was increased up to 6.92 s for the case of decreasing of flow rate. When the solenoid valve was fully closed, a initial delay time of output of MFC was increased up to 1.36 s.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.748-753
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• 2001

The objective of the present study is to visualize the pulsatile flow fields by using three-dimensional computer simulation and the PIV system. A closed flow loop system was built for the steady and unsteady experiments. The Harvard pulsatile pump was used to generate the pulsatile pressure and velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow field. Two consecutive particle images were captured by a CCO camera for the image processing at several cross section. The range validation and the area interpolation methods were used to obtain the final velocity vectors with high accuracy. The finite volume predictions were used to analyze three-dimensional flow patterns in the bifurcation model. The results of the PIV experiment and the computer simulation are in good agreement and the results show the recirculation zones and formation of the paired secondary flow distal to the apex of the bifurcated model. The results also show that the branch flow is pushed strongly to the inner wall due to the inertial force effect and helical motions are generated as the flow proceeds toward the outer wall.