• Journal of the Korea Society of Computer and Information
• /
• v.21 no.9
• /
• pp.11-18
• /
• 2016

In this paper, we propose a gas classification method using combined features for an electronic nose system that performs well even when some loss occurs in measuring data samples. We first divide the entire measurement for a data sample into three local sections, which are the stabilization, exposure, and purge; local features are then extracted from each section. Based on the discrimination analysis, measurements of the discriminative information amounts are taken. Subsequently, the local features that have a large amount of discriminative information are chosen to compose the combined features together with the global features that extracted from the entire measurement section of the data sample. The experimental results show that the combined features by the proposed method gives better classification performance for a variety of volatile organic compound data than the other feature types, especially when there is data loss.

• Nuclear Engineering and Technology
• /
• v.54 no.12
• /
• pp.4644-4651
• /
• 2022

Due to its short half-life, thoron gas has been assumed to have negligible health hazards on humans compared to radon. But, one of the decay products with a long half-life can make it to be transported to a long distance and to cause a severe internal dose through respiration. Since most commercial radon detectors can not discriminate thoron signals from radon signals, it is very common to overestimate radon doses which in turn result in biased estimation of lung cancer risk in epidemiological studies. Though some methods had been suggested to measure thoron and radon separately, they could not be used for real-time measurement because of CR-39 or LR-115. In this study, an effective method was suggested to measure radon and thoron separately from the free air. It was observed that the activity of thoron decreases exponentially due to delay time caused by a long pipe between two chambers. Therefore from two ion chambers apart in time, it was demonstrated that thoron and radon could be measured separately and simultaneously. We also developed a collimated alpha source and with this source and an SBD, we could convert the ion chamber reading to count rate in cps.

• Nuclear Engineering and Technology
• /
• v.54 no.3
• /
• pp.1037-1048
• /
• 2022

A radioactive isotope identification algorithm is a prerequisite for a low-resolution scintillation detector applied to an unmanned radiation monitoring system. In this paper, a sparse representation with dictionary learning approach is proposed and applied to plastic gamma-ray spectra. Label-consistent K-SVD was used to learn a discriminative dictionary for the spectra corresponding to a mixture of four isotopes (¹³³Ba, ²²Na, ¹³⁷Cs, and ⁶⁰Co). A Monte Carlo simulation was employed to produce the simulated data as learning samples. Experimental measurement was conducted to obtain practical spectra. After determining the hyper parameters, two dictionaries tailored to the learning samples were tested by varying with the source position and the measurement time. They achieved average accuracies of 97.6% and 98.0% for all testing spectra. The average accuracy of each dictionary was above 96% for spectra measured over 2 s. They also showed acceptable performance when the spectra were artificially shifted. Thus, the proposed method could be useful for identifying radioisotopes in gamma-ray spectra from a plastic scintillation detector even when a dictionary is adapted to only simulated data. Furthermore, owing to the outstanding properties of sparse representation, the proposed approach can easily be built into an insitu monitoring system.

• 전기의세계
• /
• v.13 no.3
• /
• pp.28-37
• /
• 1964

It is the intention of this thesis to discriminate and investigate the cause of the shaft vibration of the vertical type hydroelectric power generator with respect to electrical, mechanical and hydraulic aspects, and to analyze the vibration which will occure by the each cause investigated above. In order to test the shaft vibration of No.1 generator in Hwachon, Korea new measurement method and measuring equipments were designed. In practice the shaft vibration of the generator was measured by above equipments and analyzed by the discriminative method. Detailed explanation for the designed measurement method and instruments is presented, and the results which I had tested three times for the generator No.1 in Hwachon power plant are added. As a appendix the mechanism and causes of the thrust bearing's wear and remarks for the runner are written.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.344-345
• /
• 2006

The linear intercept (LI) method was used to quantitatively measure the intercepts of WC grains in nano-grained WC-10Co hardmetal. When the surveyed intercept numbers of WC grain exceeded 200, the statistic data for the mean grain size of WC were reproduced. The discriminative minimal grain size of used LI method was 12 nm; the maximum intercept of WC grain was 109 nm; the average intercept of WC grains was 45 nm and the corresponding 3D mean grain size of WC was 70 nm which is agreeable with the XRD outcome.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.6
• /
• pp.625-632
• /
• 2001

Statement of Problem. Objective and quantitative measurement of implant stability is very important from implant installation to long-lasting maintenance period thereafter. Purpose of study. This study was to evaluate and compare two ISQ and PTVs on the implant stability measurements according to the increased effective implant length. Materials and methods. Twenty self-tapping fixtures were installed in the bovine scapula and in 10 of those for group I, ISQ and PTVs were obtained in the vertical/horizontal directions according to the increased effective implant length using $Osstell^{TM}$ and $Periotest^{(R)}$. After stability measurement, removal torques were measured between the after installation and after thread exposure group. Results. ISQ and PTVs showed decreased and increased values according to the increased abutment length. Apart from PTVs, ISQ values were shown higher in horizontal direction to the long axis of bone in both the after installation and the after thread exposure groups. Removal torque values were shown higher in after installation group. Conclusion. From the results of this study, implant stability measurement using resonance frequency analysis was more sensitive and discriminative than PTVs measurement.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.6
• /
• pp.3086-3103
• /
• 2017

Video images captured by vehicle cameras often contain blurry or dithering frames due to inadvertent motion from bumps in the road or by insufficient illumination during the morning or evening, which greatly reduces the perception of objects expression and recognition from the records. Therefore, a real-time electronic stabilization method to correct fuzzy video from driving recorders has been proposed. In the first stage of feature detection, a coarse-to-fine inspection policy and a scale nonlinear diffusion filter are proposed to provide more accurate keypoints. Second, a new antiblurry binary descriptor and a feature point selection strategy for unintentional estimation are proposed, which brought more discriminative power. In addition, a new evaluation criterion for affine region detectors is presented based on the percentage interval of repeatability. The experiments show that the proposed method exhibits improvement in detecting blurry corner points. Moreover, it improves the performance of the algorithm and guarantees high processing speed at the same time.

• Korean Journal of Acupuncture
• /
• v.24 no.2
• /
• pp.99-112
• /
• 2007

Objectives : It was to translate three neck and spinal pain disability questionnaires - the Neck Disability Index (NDI), the Neck Pain and Disability Scale (NPDS), and the Functional Rating Index (FRI) - into Korean language, and evaluate the psychometric properties of Korean versions of questionnaires to achieve a good cross-cultural adaptation. Methods : Forty (23 males, 17 females) subjects aged from 15 to 64 years old, participated to examine test-retest reliability. One hundred and eighty (76 males, 104 females) subjects with a primary diagnosis of non-specific neck pain and 81 healthy volunteers were undertaken to examine internal consistemcy, discriminative validity and longitudinal construct validity. Versions of each questionnaire in idiomatic modern Korean were developed using a procedure proposed by Beaton et al. (2000). To assess reliability, the Intraclass Correlation Coefficient (ICC $_{(2,1)}$) was calculated. Internal consistency was evaluated by Cronbach's alpha. Discriminative validity was examined with independent-group t-tests. Responsiveness was tested by calculating the effect size and standardized response mean for each questionnaire and using Pearson' s r and the area under the receiver operating characteristic curve analysis. Results : Test-retest reliability ofthe translated versions of the three disability questionnaires was excellent (ICC $_{(2,1)$ = 0.86-0.90). High internal consistency was found in the three disability questionnaires (Cronbach's alpha ranged from ${\alpha}=0.88$ for the FRI to ${\alpha}=0.96$ for the NPDS and 0.82 for the Short Form McGill Pain Questionnaire(SFMPQ)). the VAS subscale of the SFMPQ was found to be the most responsive of the subscales (ES=1.44, SRM=1.37). The VAS was also the most responsive pain and disability index in internal responsiveness analysis, although disability indices showed marginally better responsiveness when compared with external standards. No floor or ceiling effects were observed. Conclusions : It is concluded that the questionnaires were successfully translated and exhibit acceptable measurement properties, and may suggest that they are suitable for use in clinical and research application.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.45 no.5
• /
• pp.881-891
• /
• 2021

This study proposes a simple drape measurement method for the 3D virtualization of garments. The proposed method uses angles or disks of different diameters to evaluate the drape properties easily. We divided 710 fabrics into ten groups based on the drape coefficient, of which 49.6% had drape coefficients of 30 or less. The drape properties were measured to classify the groups into smaller clusters using the angle formed when the center of the fabric was fixed. Accordingly, three clusters were formed for 60° and 100° angles. A method was devised using ten disks of different diameters to classify the remaining two clusters, except the cluster containing only the D10 group (D1-D5 and D5-D9). Three criteria-grade match, a sum of deviation, and standardization of deviation-were used for the classifications. The discriminative ability between groups was high for D1-D5 with disks with 24.0 and 25.5 cm diameters. Furthermore, a disk with a diameter of 16.5 cm was effective for D5-D9. The three-dimensional drape shapes were unique for the ten groups, which can be utilized as fundamental data for 3D virtualization.

• Journal of Korean Academy of Nursing
• /
• v.52 no.1
• /
• pp.80-91
• /
• 2022

Purpose: This study developed an instrument to evaluate the health empowerment of North Korean women refugees and examined its validity and reliability. Methods: Through literature review and focused group interviews, 66 preliminary items with three constructs, including perceived control, perceived competence, and goal internalization were selected based on Menon's psychological health empowerment model. A questionnaire survey was conducted with 239 North Korean women refugees in the community from August 31 to September 4, 2020. Content, construct, convergent, and discriminative validity were evaluated. Cronbach's α was used to evaluate the reliability of scale. Results: The final instrument consisted of 31 items with three factors that were identified through confirmatory factor analysis. The convergent validity showed that the correlation coefficient was .52 (p < .001), which confirmed the validity of the developed measurement tool. Cronbach's α for all the items was .94, and Cronbach's α for the factors was .76~.91. Conclusion: This health empowerment scale has been developed to include aspects of health empowerment, provide a conceptual framework, and offer objective indicators to evaluate the effectiveness of a health education program.