• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.4
• /
• pp.312-319
• /
• 2014

When distributed generation such as a wind power system is connected to the grid, it should meet grid requirements like IEEE Std. 1547, which regulates the anti-islanding method. Since the islanding may cause damage on electrical equipments or safety hazards for utility line worker, a distributed generation should detect it as soon as possible. This paper proposes a hybrid anti-islanding method coupled with the active and passive detection methods. To enhance the harmonic extraction capability for an active harmonic injection method, cascaded second-order band-pass filter and signal processing scheme are employed. Simulation and experiments are carried out under the islanding test condition specified in IEEE Std. 1547. Passive over/under voltage and over/under frequency methods are combined with the active method to improve the detection speed under certain condition. The simulation and experimental results are presented to verify that the proposed hybrid anti-islanding method can effectively detect the islanding.

• Journal of Animal Science and Technology
• /
• v.61 no.1
• /
• pp.41-46
• /
• 2019

Different methodologies in hair cortisol extraction may alter the final output. Thus finding the standard methodology according to a laboratory facilities is pivotal. This study was carried out to validate the feasibility of two methods of grinding hair for cortisol extraction in Korean native (Hanwoo) cattle. Hair from nine cattle including mature cows, heifers, and calves were assigned to one of the following methods for grinding hair; 1) using bead beater (BB) and 2) using surgical scissors (SS). Hair samples (> 1 g) were harvested from forehead of each individual twice (first and second measurement) to validate the results. To improve the accuracy of the obtained data, each sample was duplicated into two wells during enzyme immunoassay (EIA) analysis. Overall comparison of hair cortisol concentration (HCC) showed that the data within the range (out of the range) of standards provided by the EIA kit were 88.9% (11.1%) and 66.7% (33.3%) for BB compared with SS, respectively. In the first measurement, application of BB was tended to show higher (p = 0.056) amount of HCC compared with SS. In the second measurement application of BB showed higher (p = 0.0028) amount of HCC compared with SS. Among the cattle, calves showed higher HCC using BB compared with SS (p < 0.05). Application of BB in hair grinding methodology for Hanwoo cattle may improve cortisol extraction in comparison to application of SS method, with more consistency. Thus, it would be the preferable method to use.

• The korean journal of orthodontics
• /
• v.52 no.4
• /
• pp.258-267
• /
• 2022

Objective: This study aimed to evaluate the superimposition accuracy of digital modes for measuring tooth movement in patients requiring anterior retraction after premolar extraction based on the proposed reference regions. Methods: Forty patients treated with bilateral maxillary first premolar extraction were divided into two groups: moderate retraction (< 7.0 mm) and maximum retraction (≥ 7.0 mm). Central incisor displacement was measured using cephalometric superimpositions and three-dimensional (3D) digital superimpositions with the 3rd or 4th ruga as the reference point. The Wilcoxon signed-rank test and linear regression analyses were performed to test the significance of the differences and relationships between the two measurement techniques. Results: In the moderate retraction group, the central incisor anteroposterior displacement values did not differ significantly between 3D digital and cephalometric superimpositions. However, in the maximum-retraction group, significant differences were observed between the anteroposterior displacement evaluated by the 3rd ruga superimposition and cephalometric methods (p < 0.05). Conclusions: This study demonstrated that 3D digital superimpositions were clinically as reliable as cephalometric superimpositions in assessing tooth movements in patients requiring moderate retraction. However, the reference point should be carefully examined in patients who require maximum retraction.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.5
• /
• pp.653-662
• /
• 2022

Recently, various researches have been made on a fingerprint classification method using Convolutional Neural Networks (CNN), which is widely used for multidimensional and complex pattern recognition such as images. The CNN-based fingerprint classification method can be executed by integrating the two-step process, which is generally divided into feature extraction and classification steps. Therefore, since the CNN-based methods can automatically extract features of fingerprint images, they have an advantage of shortening the process. In addition, since they can learn various features of incomplete or low-quality fingerprints, they have flexibility for feature extraction in exceptional situations. In this paper, we intend to identify the research trends of CNN-based fingerprint classification and discuss future direction of research through the analysis of experimental methods and results.

• Journal of Korean Dental Science
• /
• v.16 no.2
• /
• pp.204-210
• /
• 2023

Lesch-Nyhan syndrome is a rare X-linked recessive disorder characterized by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyl transferase, which is important in the metabolism of purines. Prevalence of Lesch-Nyhan syndrome is 1:100,000 to 1:380,000 live births, and Lesch-Nyhan syndrome mainly affects males. It is characterized by neurologic dysfunction, uric acid overproduction, and cognitive and behavioral disturbances. The self-mutilation is the most distinctive symptom in Lesch-Nyhan syndrome, appearing about 1 year of age. It is expressed as persistent bites in the oral mucosa, tongue, lips, and fingers, which leads to the total or partial destruction of the affected tissues. Several medical and dental management methods might be performed in Lesch-Nyhan syndrome patients. Dental approaches to prevent injuries caused by self-mutilation include treatments with oral appliances such as mouth guards or lip bumpers, extraction, and orthognathic surgery. This report described two brothers with Lesch-Nyhan syndrome, who injured themselves on oral tissues. The methods of tooth reduction and extraction were performed to prevent injuries caused by self-mutilation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.3
• /
• pp.439-445
• /
• 2014

This study aimed to determine the quality characteristics of ginseng seed oil as well as evaluate the efficacy of ginseng seed oil as a food resource. Ginseng seed oil was obtained by different extraction methods; from solvent extraction oil, supercritical fluid extraction oil, and screw pressed extraction oil. Total unsaturated fatty acids were present at 97.72~97.92%. Oleic acid (80.13~81.16%) was the highest, followed by linoleic acid (14.98~15.69%). The total phenol content (mg gallic acid equivalent/100 g oil) was higher in screw pressed extraction oil ($56.32{\pm}1.47$) compared to others. ${\gamma}$-Tocopherol was only present in ginseng seed oil and screw pressed extraction oil showed the highest levels of ${\gamma}$-tocopherol ($5.95{\pm}0.25$ mg/100g oil) among the tested samples. Screw pressed extraction oil showed the greatest oxidative stability with an induction time of 16.58 hours. Acid values and peroxide values of ginseng seed oil increased with increasing storage period. The total phenol and ${\gamma}$-tocopherol contents were higher in screw pressed extraction oil than in other ginseng seed oils, which suggests that screw pressed extraction oil has the greatest oxidative stability.

• Proceedings of the IEEK Conference
• /
• 2001.06d
• /
• pp.269-272
• /
• 2001

In speech recognition technology, the utterance of every talker have special resonant frequency according to shape of talker's lip and to the motion of tongue. And utterances are different according to each talker. Accordingly, we need the superior moth-od of speech feature parameter extraction which reflect talker's characteristic well. This paper suggests the modified-MfCC combined existing MFCC with gammatone filter. We experimented with speech data from telephone and then we obtained results of enhanced speech recognition rate which is higher than that of the other methods.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.765-768
• /
• 1998

Level set method is used for extracting a shape within an image. This method is based on the ideas developed by osher and sethian to model propagating solid/liquid interfaces moving with curvature-dependent speeds. In this paper, we propose the new generalized formulation and stopping function of evolution for more accurate extraction of shape. Our method shows good results in some cases compared with the conventional ones.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.578-581
• /
• 2006

This study was performed to develop acid-soluble extraction solution and water-soluble extraction solution for hardened concrete. By use of this potentiometric method one can determinate chloride ion concentration in hardened concrete without pre-treatment and it can be used on-site.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.5
• /
• pp.71-81
• /
• 1997

This paper proposes noun and affix extraction methods using conjunctive information for making an automatic indexing system thorugh morphological analysis and syntactic analysis. The korean language has a peculiar spacing words rule, which is different from other languages, and the conjunctive information, which is extracted from the rule, can reduce the number of multiple parts of speech at a minimum cost. The proposed algorithms also solve the problem that one word is seperated by newline charcter. We show efficiency of the proposed algorithms through the process of morhologica analyzing.