• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.33-36
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• 2016

The investigation on the verification of availability simulation for small-scale plant has been carried out. This study focuses on the availability variation induced by number of equipment and iteration with failure density function. The equipment classification of small-scale plant and failure type and the methodologies on Monte-Carlo simulation are established. The availability deviation with programs showed under Max. 1.7% for the case of normal function. This method could be used to availability evaluation of small-scale plant, but calibration of the failure density function is necessary for general application.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.943-949
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• 2000

In object analysis, line and curve finding plays a universal role. And, it can be accomplished by detecting ridges and ravines in digital gray-scale images. In this paper, we present a new method of detecting ridges and ravines by using local min and max operations. This method uses erosion and dilation properties of these fuzzy logic operations and requires no information of ridge or ravine direction, so that the method is simple and easy in comparison with the conventional analytical methods. The experimental results show that the technique has a strong ability in finding ridges and ravines.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.8
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• pp.181-191
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• 1994

A new method for enhancing blurred images using fuzzy logic concepts is proposed. Blurred images contain blurred boundaries which make it difficult to detect edges and segment areas in images. In order to sharpen blurred edges local contrast information of an image and erosion/dilation properties of local min/max operations are used in which local min/max operations are fuzzy logic operations. so that given images are transformed to fuzzy images and then these operations are applied on them. In this method the sharpening operation can be iteratively applied to the image to get better deblurring effect and gray-scale "salt-and-pepper" noises are suppressed. the efficiency of our algorithm is demonstrated through experimental results obtained with artificially-made blurred images and real blurred images.

• Journal of Magnetics
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• v.9 no.3
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• pp.75-78
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• 2004

Magnetic transmission soft X-ray microscopy has been used to study element-specifically the magnetization reversal behavior of ${(Co_{84}Cr_{16})}_{87}Pt_{l3}$ alloy thin films with a lateral resolution of 35 nm. Our results indicate that the magnetization switching is carried out by a random nucleation process that can be attributed to the reversal of individual grains. We found evidence of a large distribution of the switching fields at the nanogranular length scale, which has to be considered seriously for applications of CoCrPt systems as magnetic high density storage materials.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.447-454
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• 2004

During the hierarchical formation of large scale structure in the universe, the progressive collapse and merging of dark matter should inevitably drive shocks into the gas, with nonthermal particle acceleration as a natural consequence. Two topics in this regard are discussed, emphasizing what important things nonthermal phenomena may tell us about the structure formation (SF) process itself. 1. Inverse Compton gamma-rays from large scale SF shocks and non-gravitational effects, and the implications for probing the warm-hot intergalactic medium. We utilize a semi-analytic approach based on Monte Carlo merger trees that treats both merger and accretion shocks self-consistently. 2. Production of $^6Li$ by cosmic rays from SF shocks in the early Galaxy, and the implications for probing Galaxy formation and uncertain physics on sub-Galactic scales. Our new observations of metal-poor halo stars with the Subaru High Dispersion Spectrograph are highlighted.

• The Korean Journal of Applied Statistics
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• v.1 no.2
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• pp.27-33
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• 1987

Let $\Pi_i, \cdots, \Pi_k$ denote k gamma distributions with a common known shape parameter (degrees of freedom) r and scale parameters $\theta_1, \cdots, \theta_k$, respectively. Kim proposed an improved lower bound LB$(\delta^*)$, which concerns a two-stage elimimation type procedure for selecting the population associated with the largest scale parameter $max_{1\leqi\leqk} \theta_i$. The design constants (nr, mr, c) are given for k=4(1)10, $p^*=.95,.90 and \delta^*=1.75,2.0$. With these design constants, a comparison study was made with the procedure of Lee and Choi. As can be seen from the table, these are moderate amount of savings in the expected total sample size. Thus, together with the result in Lee and Choi, the two-stage procedure can perform much better than a single stage procedure.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.114-123
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• 2003

The current paper proposes a new vertex selection scheme for polygon-based contour coding. To efficiently characterize the shape of an object, we incorporate the curvature information in addition to the conventional maximum distance criterion in vertex selection process. The proposed method consists of "two-step procedure." At first, contour pixels of high curvature value are selected as key vortices based on the curvature scale space (CSS), thereby dividing an overall contour into several contour-segments. Each segment is considered as an open contour whose end points are two consecutive key vortices and is processed independently. In the second step, vertices for each contour segment are selected using progressive vertex selection (PVS) method in order to obtain minimum number of vertices under the given maximum distance criterion ( $D_{max}$$^{*}$). Furthermore, the obtained vortices are adjusted using the dynamic programming (DP) technique to optimal positions in the error area sense. Experimental results are presented to compare the approximation performances of the proposed and conventional methods.imation performances of the proposed and conventional methods.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.976-986
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• 1996

BACKGROUND : Dyspnea is common among patients with cardiopulmonary disease, and "daily disability" is defined as a functional impairment resulting from exercise intolerance. The maximal oxygen uptake(VO2max) during exhausting work is not only the best single physical indicator of the capacity of a man for sustaining hard muscular work, but also the most objective method by which one can determine the physical fitness of an individual as reflected by his cardiovascular system. However, the expense, time and personnel requirements make this procedure prohibitive for testing large group. The walking test is well-known type of exercise and it cost nothing to perform and have good reproducibility. Thus we performed the walking test and investigated correlations with spirometry, ABG and exercise test. METHOD: We observed the walking test and exercise test by cycle ergometer in 37 patients who visited our hospital because of dyspnea. Arterial blood gas analysis and spiromety, dyspnea index were performed, too. RESULT : (1) The VO2max was significantly lower in patients with COPD and cardiovascular disease than asthma and dyspnea on exertion group(p<0.05). The walking test distance was also lower in former. (2) The 12 minute walking test was significantly correlated with VO2max, PaCO2, FVC(%), FEV1(%) in all patients(p<0.05), and the walking test was only conelated with VO2max in patients with COPD(p<0.05). (3) In COPD patients, the VO2max was best correlated with FEV1(%) and FVC(%) and significantly correlated with walking test. But there was no correlation between walking test and FEV1(%) & FVC(%). (4) The 6 minute walking test was well correlated with 12 minute walking test(r=0.92. p<0.01). CONCLUSION : The walking test is the simple method for assessing exercise performance in patient with cardiopulmonary disease and a reliable indicator for VO2max. And the walking test is practical method for assessing on everyday disability rather than maximal exercise capacity. The 6 minute walking test is highly correlated with 12 minute walking test and a less exhausting for the patients and a time-saving for the investigator.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.65-71
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• 2003

This research aims the production of anti-tumor substances through in vitro culture of hairy roots transformed by Agrobacterium rhizogenes in Artemisia sylvatica MAX and the effect of culture conditions on optimum growth of hairy roots. We investigated the optimum medium, pH, carbon source, sucrose, light, Fe and polyamine conditions of various lines of hairy roots (NK3, NK4, YX. NK3-10) induced from Artemisia sylvatica to increase the optimum growth of hairy roots. MS medium was the best for optimum growth of hairy root clone, NK3-S10. The optimum culture period was 4 weeks for NK3-S10. The optimum sucrose concentration was 3.5%. The optimum concentration of FeSO$_4$, spermine and spermidine was 0.1 mM, 10 mM and 100 mM, respectively.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.57-67
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• 1998

Purpose : This study was undertaken to determine the preoperative predictors of mortality and morbidity after lung cancer resection. Method: During the period from October 1, 1995 to August 31, 1996, a prospective study was conducted in 92 lung resection candidates diagnosed as lung cancer. For preoperative predictors of nonpulmonary factors, we considered age, sex, weight loss, hematocrit, serum albumin, EKG and concomitant illness, and for those of pulmonary factors, smoking history, presence of pneumonia, dyspnea scale(1 to 4), arterial blood gas analysis with room air breathing, routine pulmonary function test. And predicted postoperative(ppo) pulmonary factors such as PPO-$FEV_1$, ppo-diffusing capacity(DLco), predicted postoperative product(PPP) of ppo-$FEV_1%{\times}ppo$-DLco% and ppo-maximal $O_2$ uptake($VO_2$max) were also considered. Results: There were 78 men and 14 women with a median age of 62 years(range 42 to 82) and a mean $FEV_1$ of $2.37\pm0.06L$. Twenty nine patients had a decreased $FEV_1$ less than 2.0L. Pneumonectomy was performed in 26 patients, bilobectomy in 12, lobectomy in 54. Pulmonary complications developed in 10 patients, cardiac complications in 9, other complications(empyema, air leak, bleeding) in 11, and 16 patients were managed in intensive care unit for more than 48hours. Three patients died within 30 days after operation. The ppo-$VO_2$max was less than 10ml/kg/min in these three patients, but its statistical significance could not be determined due to small number of patients. In multivariate analysis, the predictor related to postoperative death was weight loss(p<0.05), and as for pulmonary complications, weight loss, dyspnea scale, ppo-DLco and extent of resection(p<0.05). Conclusions: Based on this study, preoperative nonpulmonary factors such as weight loss and dyspnea scale are more important than the pulmonary factors in the prediction of postoperative mortality and/or morbodity in lung resection candidates, but exercise pulmonary fuction test may be useful Our study suggests that ppo-$VO_2$max value less than 10ml/kg/min is associated with death after lung cancer resection but further studies are needed to validate this result.