• ETRI Journal
• /
• v.34 no.2
• /
• pp.184-189
• /
• 2012

In this paper, we propose a novel approach to statistical model-based voice activity detection (VAD) that incorporates a second-order conditional maximum a posteriori (CMAP) criterion. As a technical improvement for the first-order CMAP criterion in [1], we consider both the current observation and the voice activity decision in the previous two frames to take full consideration of the interframe correlation of voice activity. This is clearly different from the previous approach [1] in that we employ the voice activity decisions in the second-order (previous two frames) CMAP, which has quadruple thresholds with an additional degree of freedom, rather than the first-order (previous single frame). Also, a soft-decision scheme is incorporated, resulting in time-varying thresholds for further performance improvement. Experimental results show that the proposed algorithm outperforms the conventional CMAP-based VAD technique under various experimental conditions.

• Mass Spectrometry Letters
• /
• v.10 no.3
• /
• pp.93-101
• /
• 2019

Algorithms and software for predicting tandem mass spectra have been developed in recent years. In this work, we explore how distinct in silico $MS^2$ spectra are predicted for isomers, i.e. compounds having the same formula and similar molecular structures, to differentiate between them. We used the CFM-ID 2.0/3.0 predictor with regard to (a) test compounds, whose experimental mass spectra had been randomly sampled from the MassBank of North America (MoNA) collection, and to (b) the most widespread isomers of test compounds searched in the PubChem database. In the first validation test, in silico mass spectra constitute a reference library, and library searches are performed for test experimental spectra of "unknowns". The searches led to the true positive rate (TPR) of ($46-48{\pm}10$)%. In the second test, in silico and experimental spectra were interchanged and this resulted in a TPR of ($58{\pm}10$)%. There were no significant differences between results obtained with different metrics of spectral similarity and predictor versions. In a comparison of test compounds vs. their isomers, a statistically significant correlation between mass spectral data and structural features was observed. The TPR values obtained should be regarded as reasonable results for predicting tandem mass spectra of related chemical structures.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.28 no.1
• /
• pp.76-81
• /
• 2023

A new test circuit for an MMC-based valve HVDC power converter is proposed. The proposed scheme satisfies the required clauses from IEC-62501. The valve test current contains second harmonic component and DC offset as well as a fundamental component that is quite similar to the real operating arm current of MMC based HVDC power system. The structure of the proposed test circuit is simple compared to conventional test circuits. Furthermore, the power supply voltage rating of the proposed test circuit is reduced dramatically around 20% of the conventional scheme with the same current rating. The validity of the proposed test circuit is verified through simulation and experimental results.

• International Journal of Computer Science & Network Security
• /
• v.21 no.12
• /
• pp.335-343
• /
• 2021

The study aimed to elucidate how to design a learning environment on the premise of micro-learning (ML) and investigate its impact on website designing skills and achievement motivation among secondary school students. Adopting the experimental approach, data were collected through an achievement test, a product evaluation form, and a test to gauge motivation for achievement. The sample was divided into two experimental groups. Results revealed statistically significant differences at 0.05≥α between the mean scores of the two groups that experienced ML, irrespective of the two modes of presenting the video in the pre-test and post-test, as for the test of websites design skills, product evaluation form, and achievement motivation test. Besides, there have been statistically significant differences at 0.05≥α between the mean scores of the first experimental group that had exposure to ML using the split-video presentation style and the scores of the second experimental group that underwent ML using continuous video presentation style in the post cognitive test of website design and management skills in favor of the group that had segmented-video-presentation ML. Another salient finding is the nonexistence of significant differences at 0.05≥α between the mean scores of the first experimental group that underwent segmented-video-presentation ML and the grades of the second experimental group that received ML with continuous video presentation style in the post-application of the product scorecard of websites designing skills and the motivation test. In light of these salient findings, the study recommended using ML in teaching computer courses at different educational stages in Saudi Arabia, training computer and information technology teachers to harness ML in their teaching and using ML in designing courses at all levels of education.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.19 no.5
• /
• pp.1191-1194
• /
• 2005

The aim of this study was to investigate the change of Heart Rate Variability(HRV) that mild cold stimulus on the forehead of healthy men induces. 34 healthy male subjects participated in the experiments. On the first test series, 15 subjects were applied to the mild cold stimulus by the devise for cold stimulation. In the second test series, 10 subjects With heat Syndrome and 5 subjects With cold Syndrome were applied to the mild cold Stimulus. Aa a additional test, 4 subjects with cold syndrome were applied to the warm stimulus in the last test series. We analyzed the HRV through measuring electrocardiogram.(ECG). The result of this study is comparatively clear. In the first test series, mild cold stimulus made parasympathetic nervous system be activated. In the second test series, mild cold stimulus made parasympathetic nervous system be activated both in subjects with heat syndrome and subjects with cold syndrome, and heat syndrome shows more active parasympathetic nervous system rather than cold syndrome subjects do. In the last test series, 2 subjects with cold syndrome respond the mild cold stimulus. That means warm stimulus of cold condition subjects made parasympathetic nervous system active in 2 of 4 subjects. We found out that mild cold stimulus on forehead makes parasympathetic nervous system be activated in healthy male, and it can be interpreted that mild cold stimulus make healthy human be relaxed. Also, subjects have different fondness of thermal stimulus according to their Cold or Heat condition Preferences. Last test series shows that we need to investigate effect of the warm stimulus heat syndrome subjects.

• Communications of Mathematical Education
• /
• v.37 no.4
• /
• pp.697-715
• /
• 2023

The purpose of this study is to investigate the overall understanding of patterns by second- and third-grade elementary school students. For this purpose, 12 classes per grade were selected from 10 schools, and a 46-item test was administered to 216 second graders and 223 third graders. The results of the study showed that in most cases, there was no statistically significant difference in the understanding of patterns between second- and third-graders. The exception occurred regarding the 10 items of identifying the structure of a pattern: Second-graders did better than third-graders regarding 8 items, whereas vice versa regarding 2 items. The items that both second- and third-graders struggled with included finding multiple components of a given pattern, comparing the structures between patterns, and guessing a particular term in an open pattern. Based on these findings, this paper discusses second- and third-graders' understanding of patterns and suggestions for further instruction.

• Journal of the Korea Safety Management & Science
• /
• v.24 no.4
• /
• pp.117-124
• /
• 2022

This study collected powder extinguishers with 6-10 years of elapsed life from January 2012 to January 2017 in market, factory, and apartment areas to experiment with changes in fineness and to examine the characteristics of extinguishing power. First, in the case of ABC powder, 98.3 wt% of the 8-year market area and 98.6 wt% of the 10-year apartment complex were found to be inappropriate in the first, second, and third arithmetic average analysis of the powder extinguisher from 6 to 10 years. That is, the fine distribution and size of the powder extinguishing agent particles should be managed within an appropriate range. It is analyzed that the powder fire extinguisher may experience a change in the fineness of the powder depending on the external environment exposure, placement, management status, and age of use, resulting in a decrease in digestive power or inability to radiate. Second, the fire extinguisher cannot be used in the initial fire suppression depending on the place of deployment, the environment of deployment, the progress of the number of years of use, and maintenance, so it is necessary to strengthen the device that enables fire extinguisher maintenance and inspection. Third, in the manufacturing process, the charging method should also be reviewed in consideration of the conditions of the workplace, the humid season, and the rainy environment.

• CELLMED
• /
• v.14 no.10
• /
• pp.12.1-12.13
• /
• 2024

This study investigated the psychological effects of the creative music fairy tale 'I am a music creator' education program, which was implemented as the convergence educational program of the Seocho Innovation Education District in 2021 for a total of 8 weeks for elementary school students, on Musical Interest, Self-Efficacy, and Self-Esteem. Before verifying the effects after conducting the education program for a total of 8 weeks, a homogeneity verification of the group composition was conducted through a pre-measurement, and it was confirmed that the composition by gender and grade was homogeneous. The results of this study are as follows. First, the results of the pre-test/post-test by research subject showed that the post-test scores in Musical-Interest and Self-Efficacy were slightly higher than the pre-test scores, but there was no significant difference. When Self-Esteem was considered, There was a significant difference, and the post-test scores showed a higher average than the pre-test scores. Second, the results of the pre-test/post-test by gender of the research subject showed that the post-test scores in Musical-Interest, Self-Efficacy, and Self-Esteem for male students were slightly higher than the pre-test scores, but there was no significant difference. The post-test scores in Musical-Interest and Self-Efficacy for female students were slightly higher than the pre-test scores, but there was no real significant difference. Self-Esteem showed a significant difference, and the post-test scores showed a higher average than the pre-test scores. Third, the results of the pre-test/post-test by grade of the research subject showed that the post-test scores in Musical-Interest, Self-Efficacy, and Self-Esteem for second graders were slightly higher than the pretest scores, but there was no real significant difference. In the 3rd grade, there was a significant difference in the sub-factors of Musical-Interest, interest in music classes, and Self-Esteem, and the post-score showed a higher average than the pre-score. In the 4th grade, the post-scores were slightly higher than the pre-scores in Musical-Interest, Self-Efficacy, and Self-Esteem, but there was no significant difference. Through these results, it was confirmed that the integrated music activity approach has a positive influence on elementary school students' Musical-Interest, Self-Efficacy, and Self-Esteem, which are formed in the process of growth and development.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.1
• /
• pp.58-64
• /
• 2018

PURPOSE. The aim of this study was to design an intraoral environment simulator and to assess the accuracy of two intraoral scanners using the simulator. MATERIALS AND METHODS. A box-shaped intraoral environment simulator was designed to simulate two specific intraoral environments. The cast was scanned 10 times by Identica Blue (MEDIT, Seoul, South Korea), TRIOS (3Shape, Copenhagen, Denmark), and CS3500 (Carestream Dental, Georgia, USA) scanners in the two simulated groups. The distances between the left and right canines (D3), first molars (D6), second molars (D7), and the left canine and left second molar (D37) were measured. The distance data were analyzed by the Kruskal-Wallis test. RESULTS. The differences in intraoral environments were not statistically significant (P>.05). Between intraoral scanners, statistically significant differences (P<.05) were revealed by the Kruskal-Wallis test with regard to D3 and D6. CONCLUSION. No difference due to the intraoral environment was revealed. The simulator will contribute to the higher accuracy of intraoral scanners in the future.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.1
• /
• pp.23-29
• /
• 2016

The Second Shutdown Drive Mechanism (SSDM) provides an alternate and independent means of reactor shutdown. The Second Shutdown Rods (SSRs) of SSDMs are poised at the top of the core by the hydraulic force driven from a hydraulic system during normal operation. The rods drop by gravity when a trip is commended by a Reactor Protection System, Alternate Protection System, Automatic Seismic Trip System or operator by means of power off solenoid valves of hydraulic system. This paper describes the test results of seismic qualification of a prototype SSDM hydraulic system to demonstrate that its structural integrity and operability (functionality) are maintained during and after seismic excitations, that is, an adequacy of the SSDM design. From the results, this paper shows that the SSDM hydraulic system satisfies all its design requirements without any malfunctions during and after seismic excitations.