• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.67-73
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• 2001

Three dimensional, elastic-plastic finite element(FE) analyses for circumferential through-wall cracked pipes under combined tension and bending are performed using actual tensile data of stainless steel, for two purposes. The first one is to validate the recently-proposed enhanced reference stress (ERS) method to estimate the J-integral and COD for circumferential through-wall cracked pipes under combined tension and bending. The second one is to compare those results with the GE/EPRI estimations. The FE results of the J-integral and the COD, resulting from six cases of proportional and non-proportional combined tension and bending, compare very well with those estimated from the proposed method. Excellent agreements of the proposed method with the detailed FE results provide sufficient confidence in the use of the proposed method to the Leak-Before-Break(LBB) analysis of through-wall cracked pipes under combined tension and bending.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.184-188
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• 2006

The purpose of the recovery experiment in clinical chemistry is performed to estimate proportional systematic error. We must know all measurements have some error margin in measuring analytical performance. Proportional systematic error is the type of error whose magnitude increases as the concentration of analyte increases. This error is often caused by a substance in the sample matrix that reacts with the sought for analyte and therefore competes with the analytical reagent. Recovery experiments, therefore, are used rather selectively and do not have a high priority when another analytical method is available for comparison purposes. They may still be useful to help understand the nature of any bias revealed in the comparison of kit experiments. Recovery should be expressed as a percentage because the experimental objective is to estimate proportional systematic error, which is a percentage type of error. Good recovery is 100.0%. The difference between 100 and the observed recovery(in percent) is the proportional systematic error. We calculated the amount of analyte added by multiplying the concentration of the analyte added solution by the dilution factor(mL standard)/(mL standard + mL specimen) and took the difference between the sample with addition and the sample with dilution. When making judgments on method performance, the observed that the errors should be compared to the defined allowable error. The average recovery needs to be converted to proportional error(100%/Recovery) and then compared to an analytical quality requirement expressed in percent. The results of recovery experiments were total protein(101.4%), albumin(97.4%), total bilirubin(104%), alkaline phosphatase(89.1%), aspartate aminotransferase(102.8), alanine aminotransferase(103.2), gamma glutamyl transpeptidase(97.6%), creatine kinase(105.4%), lactate dehydrogenase(95.9%), creatinine(103.1%), blood urea nitrogen(102.9%), uric acid(106.4%), total cholesterol(108.5), triglycerides(89.6%), glucose(93%), amylase(109.8), calcium(102.8), inorganic phosphorus(106.3%). We then compared the observed error to the amount of error allowable for the test. There were no items beyond the CLIA criterion for acceptable performance.

• Journal of the Korean GEO-environmental Society
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• v.15 no.10
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• pp.35-42
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• 2014

This study is to evaluate Net Primary Production (NPP) using NDVI calculated by MODIS in the Nakdong river basin. This study is based on the method of using the fact that NPP is proportional to natural vegetation condition. This method is different from existing one, using remote sensed data. It is known that NPP of natural vegetation is proportional to the absorbed amount of visible light that is proportional to NDVI. Therefore, estimating NPP by using NDVI is one of the most highly useful methods. This method can be used in a wide range of areas where vegetation data can not be obtained easily or where there is not enough meterological data. This study proposes the estimating method for NPP that is based upon NDVI, which is obtained by MODIS, and verifies by comparing the NPP with empirical results.

• Korean Journal of Acupuncture
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• v.22 no.4
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• pp.175-185
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• 2005

Objective : The skill of locating acupoints accurately is an essential part of acupuncture treatment. Bone-scale has been used as a basic coordinates to locate acupoints and has been considered as an important factor of locating acupoints. This study was designed to stress the impotance of QieXunMenAn, which means pressing and rubbing softly the surface around the part pointed with proportional method, in locating acupoints. Methods and results : All expressions related with QieXunMenAn, among the descriptions of acupoint locations in ${\ulcorner}Zhenjiudacheng{\lrcorner}$, were investigated. The activity of QieXunMenAn has been regarded as an important method of locating acupoints since Neijing. QieXunMenAn means pressing and rubbing softly the surface around the part pointed with proportional method. It is a process of locating acupoint in detail by finger-sensation after locating the point with proportional method. Xianzhang, Dongmaiyingshou, and Wanwanzhong have been used to describe how to locate acupuncture-point through QieXunMenAn procedure. Xianzhong means a small depression or a pit on the surface of the body. Wanwanzhong describes that it feels very soft and tender. Descriptions related with QieXunMenAn procedures were found in around 87% of acupoint locations, thus stressing out its procedure. Conclusions : Bone-scale and QieXunMenAn do not mean different methods but the procedures that should be both performed every time when we locate most of the acupoints. Until recently, QieXunMenAn has been paid less attention that it should be. OieXunMenAn as well as bone-scale may be necessary to help locate acupoints accurately.

• Korean Journal of Oriental Medicine
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• v.16 no.2
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• pp.125-130
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• 2010

Objectives : The bone proportional cun and body cun have been used widely for the location of acupoints in oriental medical clinic. The aim of this study is to compare the two location methods. Methods : 21 students were examined for the location of 6 acupoints (each 2 points in the 3 parts of upper limb, abdomen, and lower limb) using the twe methods. The data of location were analyzed with t-test. Results : In the upper limb, the data from bone proportional cun and body cun were proved to be different significantly. However, there was no significant difference between the data from the two methods in the abdomen and lower limb. Conclusion : The results of this study demonstrate that the oriental medical doctors should be more careful in the choice of appropriate method for the location of acupoints in the upper limb, while it is not important whether they use bone proportional cun and body cun in the abdomen and lower limb.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.797-803
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• 2012

Proportional solenoid valves are a modulating type that can control the displacement of valves continuously by means of electromagnetic forces proportional to the solenoid coil current. Because the solenoid-type modulating valves have the advantages of fast response and compact design over air-operated or motor-operated valves, they have been gaining acceptance in chemical and power plants to control the flow of fluids such as water, steam, and gas. This paper deals with the auto tuning of the position controller that can provide the proportional and integral gain automatically based on the dynamic system identification. The process characteristics of the solenoid valve are estimated with critical gain and critical period at a stability limit based on implemented relay feedback, and the controller parameters are determined by the classical Ziegler-Nichols design method. The auto-tuning algorithm was verified with experiments, and the effects of the operating point at which the relay control is activated as well as the relay amplitude were investigated.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1555-1566
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• 2018

Proportional capacitor-current-feedback active damping (AD) is a common damping method for the resonance of LCL-type grid-connected inverters. Proportional capacitor-current-feedback AD behaves as a virtual resistor in parallel with the capacitor. However, the existence of delay in the actual control system causes impedance in the virtual resistor. Impedance is manifested as negative resistance when the resonance frequency exceeds one-sixth of the sampling frequency ($f_s/6$). As a result, the damping effect disappears. To extend the system damping region, this study proposes a virtual resistor-inductor-capacitor (RLC) AD method. The method is implemented by feeding the filter capacitor current passing through a band-pass filter, which functions as a virtual RLC in parallel with the filter capacitor to achieve positive resistance in a wide resonance frequency range. A combination of Nyquist theory and system close-loop pole-zero diagrams is used for damping parameter design to obtain optimal damping parameters. An experiment is performed with a 10 kW grid-connected inverter. The effectiveness of the proposed AD method and the system's robustness against grid impedance variation are demonstrated.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.49-55
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• 2019

This study proposes a robust control of a fin position servo system using the H-infinity loop-shaping method. The fin position control system has a proportional (P) position controller and a proportional-integral (PI) controller. In this work, the position control loop requires a wide bandwidth. No current control loop exists due to the compact design of the system. Hence, the controller parameters are difficult to determine using the traditional cascade design method. The $H_{\infty}$ controller design method is used to design the controller's gain to achieve good performance and robustness. First, the transfer function of the system, which can be divided into tunable and fixed parts, is derived. The tunable part includes the position P controller and speed PI controller. The fixed part includes the rest of the system. Second, the optimized controller parameters are calculated using Matlab $H_{\infty}$ controller design program. Finally, the system with optimized controller is tested by simulation and experiment. The control performance is satisfactory, and the $H_{\infty}$ controller design method is proven to be valid.

• Journal of Biosystems Engineering
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• v.8 no.2
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• pp.11-17
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• 1983

Stress distribution under a driving lugged wheel was obtained by photoelastic method. The distribution showed two distinct parts, one part is due to sinkage and other due to compression. Results of the study are summarized as follows. 1. The tangential reactions of sinkage as well as compressing parts were directly proportional to tangential load to the driving wheel, that's appeared to be thrust of the driving wheel. The normal reactions of both sinkage and compressing parts were directly proportional to the vertical load to the driving wheel, that's appeared to be resistance against wheel motion. 2. When the tangential load was constant, changing the vertical load did not show any significant thrust variation of the driving wheel. 3. Under the condition of this experiment, the ratio of vertical load to tangential load (T.L/V.L) must be greater than 1.0 in order for the wheel to roll.

• The Korean Journal of Applied Statistics
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• v.13 no.1
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• pp.197-206
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• 2000

For estimating missing cells in contingency table, we suggest an iterative method which extends IPF (Iterative Proportional Fitting) method. The suggested m~thod is not restricted by the number and the location of missing cells, and does not distort the given quasi-independency.