• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.232-235
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• 2002

An 150 kV gas cluster ion accelerator was fabricated and assessed. The change of surface morphology and surface roughness were examined by an atom force microscope (AFM) after irradiation of $CO_2$ gas clusters on Si (100) surfaces at the acceleration voltages of 50 kV. The density of hillocks induced by cluster ion impact was gradually increased with the dosage up to 5$\times$10$^{11}$ ions/$\textrm{cm}^2$. At the boundary of the ion dosage of 10$^{12}$ ions/$\textrm{cm}^2$, the density of the induced hillocks was decreased and RMS (root mean square) surface roughness was not deteriorated further. At the dosage of 5x10$^{13}$ ions/$\textrm{cm}^2$, the induced hillocks completely disappeared and the surface became very flat. In addition, the irradiated region was sputtered. $CO_2$ cluster ions are irradiated at the acceleration voltage of 25 kV to remove hillocks on indium tin oxide (ITO) surface and thus to attain highly smooth surfaces. $CO_2$ monomer ions are also bombarded on the ITO surface at the same acceleration voltage to compare sputtering phenomena. From the AFM results, the irradiation of monomer ions make the hillocks sharper and the surfaces rougher On the other hand, the irradiation of $CO_2$ cluster ions reduces the hight of hillocks and planarize the ITO surfaces. From the experiment of isolated cluster ion impact on the Si surfaces, the induced hillocks m high had the surfaces embossed at the lower ion dosages. The surface roughness was slightly increased with the hillock density and the ion dosage. At higher than a critical ion dosage, the induced hillocks were sputtered and the sputtered particles migrated in order to fill valleys among the hillocks. After prolonged irradiation of cluster ions, the irradiated region was very flat and etched.

• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.467-478
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• 2016

The accelerated failure time model or accelerated life model relates the logarithm of the failure time linearly to the covariates. The parameters in the model provides a direct interpretation. In this paper, we review some newly developed practically useful estimation and inference methods for the model in the analysis of right censored data.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.872-898
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• 2007

Pantograph sliding plate abrasion auto-detect system, one of the electric rail car auto-detecting devices, is a system that decides how much abrasion and when to replace without an inspector physically looking at the abrasion on the wet plate using machine vision, a cutting-edge technology. This paper covers the cause of deteriorating reliability that affects pantograph wet plate edge detection due to noise added to the video when it rains. In order to remove such noise, problems should be checked through Smoothing, Averaging mask and Median filter using filtering technique and stable edge detection without being affected by noise should be induced in video measurement used in machine vision technology.

• Journal of Acupuncture Research
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• v.20 no.5
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• pp.187-207
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• 2003

Objective: Recently, many studies have showed the evidences of the effect of the acupuncture treatment through scientific methods. One of these methods is functional MRI. We performed electro-acupuncture on Liv3 and observed the change of brain activation using fMRI. Methods: To see the effect of electro-acupuncture stimulation on Liv3. the experiment was carried out on 12 healthy volunteers. using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right Liv3. 2 Hz of electric stimulation was given for 30 seconds. repeated five times. with 30 seconds' intervals. The Image analysis including motion correction, talairach transformation. and smoothing was done with SPM99. Results : 1. Group averaged brain activation induced by bilateral electro-acupuncture stimulation on Liv3 activates Brodman Area 6, 13, 18, 19, 22, 31, 39, 44, 2. Group averaged brain deactivation induced by bilateral Electro-acupuncture stimulation on Liv3 activates Brodman Area 4, 6, 9, 19, 36, 37, 39. 3. Group averaged brain activation induced by unilateral(right side) electro-acupuncture stimulation on Liv3 activates Brodman Area 2, 3, 6, 9, 10, 22, 40, 42, 43. 4. Group averaged brain deactivation induced by unilateral(right side) electro-acupuncture stimulation on Liv3 activates Brodman Area 6, 18, 19, 28, 30, 31, 35, 37. 5. Brain region activated by motor stimulation activates Brodman Area 4, 6, 13, 19, 42.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.86-103
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• 2003

Objective : Recently, many studies have showed the evidences of the effect of the acupunture treatment through scientific methods. One of these methods is functional MRI. We performed electro-acupunture on Sp6 and observed the changes of brain activation using fMRI. Methods : To see the effect of electro-acupunture stimulation on Sp6, the experiment was carried out on 12 healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right Sp6, 2Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. The Image analysis including motion correction, talairach transformation, and smoothing was done with SPM99. Results : 1. Group averaged brain activation induced by bilateral eletro-acupunture stimulation on Sp6 activates Brodman Area 3, 7, 13. 2. Group averaged brain deactivation induced by bilateral eletro-acupunture stimulation on Sp6 activates Brodman Area 6, 38, 47. 3. Group averaged brain activation induced by unilateral(right side) eletro-acupunture stimulation on Sp6 activates Brodman Area 5, 6, 13, 17, 18, 19, 31, 38, 40 ptoms, back pain(32.5%) was the 4. Group averaged brain deactivation induced by unilateral(right side) eletro-acupunture stimulation on Sp6 activates Brodman Area 3, 4, 18, 21, 36, 38, 39. 5. Brain region activated by motor stimulation activates Brodman Area 3, 4, 6, 18, 19.

• Smart Structures and Systems
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• v.33 no.3
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• pp.189-199
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• 2024

To properly extract the strain components under varying operational conditions is very important in bridge health monitoring. The abnormal sensor readings can be correctly identified and the expected operational performance of the bridge can be better understood if each strain components can be accurately quantified. In this study, strain components under varying load conditions, i.e., temperature variation and live-load variation are evaluated based on field strain measurements collected from a real concrete box-girder bridge. Temperature-induced strain is mainly regarded as the trend variation along with the ambient temperature, thus a smoothing technique based on the wavelet packet decomposition method is proposed to estimate the temperature-induced strain. However, how to effectively extract the vehicle-induced strain is always troublesome because conventional threshold setting-based methods cease to function: if the threshold is set too large, the minor response will be ignored, and if too small, noise will be introduced. Therefore, an autoencoder framework is proposed to evaluate the vehicle-induced strain. After the elimination of temperature and vehicle-induced strain, the left of which, defined as the model error, is used to assess the operational performance of the bridge. As empirical techniques fail to detect the degraded state of the structure, a clustering technique based on Gaussian Mixture Model is employed to identify the damage occurrence and the validity is verified in a simulation study.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.153-159
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• 2020

Purpose: This study was conducted evaluate the influence of reconstruction parameters of micro-computed tomography (micro-CT) images on bone mineral density (BMD) analyses. Materials and Methods: The sample consisted of micro-CT images of the maxillae of 5 Wistar rats, acquired using a SkyScan 1174 unit (Bruker, Kontich, Belgium). Each acquisition was reconstructed following the manufacturer's recommendations(standard protocol; SP) for the application of artifact correction tools(beam hardening correction [BHC], 45%; smoothing filter, degree 2; and ring artifact correction [RAC], level 5). Additionally, images were reconstructed with 36 protocols combining different settings of artifact correction tools (P0 to P35). BMD analysis was performed for each reconstructed image. The BMD values obtained for each protocol were compared to those obtained using the SP through repeated-measures analysis of variance with the Dunnett post hoc test(α=0.05). Results: The BMD values obtained from all protocols that used a BHC of 45% did not significantly differ from those obtained using the SP (P>0.05). The other protocols all yielded significantly different BMD values from the SP(P<0.05). The smoothing and RAC tools did not affect BMD values. Conclusion: BMD values measured on micro-CT images were influenced by the BHC level. Higher levels of BHC induced higher values of BMD.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3865-3869
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• 2013

Background: Cigarette per day (CPD) use is a key smoking behaviour indicator. It reflects smoking intensity which is directly proportional to the occurrence of tobacco induced cancers. Self reported CPD assessment in surveys may suffer from digit bias and under reporting. Estimates from such surveys could influence the policy decision for tobacco control efforts. In this context, this study aimed at identifying underlying factors of digit bias and its implications for Global Adult Tobacco Surveillance. Materials or Methods: Daily manufactured cigarette users CPD frequencies from Global Adult Tobacco Survey (GATS) - India data were analyzed. Adapted Whipple Index was estimated to assess digit bias and data quality of reported CPD frequency. Digit bias was quantified by considering reporting of '0' or '5' as the terminal digits in the CPD frequency. The factors influencing it were identified by bivariate and logistic regression analysis. Results: The mean and mode of CPD frequency was 6.7 and 10 respectively. Around 14.5%, 15.1% and 15.2% of daily smokers had reported their CPD frequency as 2, 5 and 10 respectively. Modified Whipple index was estimated to be 226.3 indicating poor data quality. Digit bias was observed in 38% of the daily smokers. Heavy smoking, urban residence, North, South, North- East region of India, less than primary, secondary or higher educated and fourth asset index quintile group were significantly associated with digit bias. Discussion: The present study highlighted poor quality of CPD frequency data in the GATS-India survey and need for its improvement. Modeling of digit preference and smoothing of the CPD frequency data is required to improve quality of data. Marketing of 10 cigarette sticks per pack may influence CPD frequency reporting, but this needs further examination. Exploring alternative methods to reduce digit bias in cross sectional surveys should be given priority.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.432-438
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• 2009

In this paper, we evaluated the performance of the automatic classifier applied for the discrimination of acute alcoholic liver injury and chronic liver fibrosis. The classifier uses the discriminant peaks of the preprocessed Raman spectrum as a feature set. In preprocessing step, we subtract baseline and apply Savitzky-Golay smoothing filter which is known to be useful at preserving peaks. After identifying discriminant peaks from the spectra, we carried out the classification experiments using MAP and neural networks. According to the experimental results, the classifier shows the promising results to diagnosis alcoholic liver injury and chronic liver fibrosis. Classification results over 80% means that the peaks used as a feature set is useful for diagnosing liver disease.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.51-64
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• 2000

This paper presents a procedure of calculating a safety factor of the unsaturated slope suffering from the rainfall infiltration. The process of infiltration into a slope due to rainfall and its effect on the behavior of the soil slope are examined by using a two dimensional finite element flow-deformation coupled analysis. A factor of safety is calculated at various elapsed times after the commencement of rainfall as in the following procedure. First, stresses are estimated at each Gaussian point from the coupled finite element analysis. Then, the global stress smoothing method is applied to get a continuous stress field. Based on this stress field, a factor of safety is calculated for a specified slip surface by a stress integration scheme. Then, a search strategy is used to find out a critical slip surface which is associated with the minimum factor of safety. Some numerical examples are analyzed in order to study the effect of hydraulic conductivity on the slope stability during rain-induced infiltration. According to the results, local failure zone can be formed near the slope surface due to inhomogeneous distribution of hydraulic conductivity If the failure zone is once formed, then the region extends until a large amount of slide activates. Therefore the local failure can be neglected no longer in the stability analysis.