직류전동기는 속도제어가 간단하고, 출력 토크특성이 우수한 장점으로 윈치나 카고 펌프 모터 등으로 선박에서 많이 사용되었으며, 전기추진선박이 도입된 초기에는 선박용 추진전동기로도 적용되었다. 하지만 브러시와 정류기와 같은 기계적 정류장치의 단점으로 인해 최근에는 직류전동기와 전기적인 특성은 매우 유사하지만 기계적인 정류장치를 설치하지 않고 반도체 소자를 이용한 전자적인 정류장치를 사용하는 브러시리스 직류전동기의 사용이 증가하고 있다. 기존의 브러시리스 직류전동기를 구동하기 위한 인버터 시스템은 2 상여자방식을 사용하므로 역기전력파형이 사다리꼴모양으로 되며, 이로인해 전류가 흐르는 권선이 바뀌는 상전류 전환 구간에서 고조파와 토크리플이 발생하게 된다. 이러한 고조파와 토크리플을 저감하기 위한 다양한 방안이 연구되어 발표되었으며, 본 연구에서는 전력분 석프로그램을 이용하여 브러시리스 직류전동기의 구동회로에 비례적분 속도전류제어기 알고리즘을 구현한 Cascaded H-Bridge 멀티레벨 인버터를 적용하였다. 모델링한 브러시리스 직류전동기의 시뮬레이션을 통해 제안하는 전동기의 구동방식을 적용하는 경우에 기존의 구동방식에 비해 전동기 입력측 전압파형 개선과 고조파 및 토크리플이 현저히 저감되는 결과를 확인할 수 있었다.

Quality management has become an pervasive philosophy in most sectors of business. Specific movements such as statistical quality control, quality circle, total quality management, and quality management system have become embedded in business organizations. Only the companies with competitive edge can survive in the competition in global market. KSA(Korean Standards Association) established in 1962 has launched all kinds of quality education, quality standard certification service for business, and KNQA(Korean National Quality Award) system. This article considers quality competitiveness excellent company award among KNQA. We performed a statistical analysis of audit data for quality competitiveness excellent company for three years, from 2015 to 2017. By using ANOVA and two sample t-tests, the average scores of 13 evaluation fields were significantly different depending on company size and type. We proposed ways to improve the current hall of fame system. We discovered that the average scores of 13 evaluation fields in the audit data according to years and hall of fame status were not significantly different. We also showed linear relationships among 13 evaluation fields by correlation analysis and obtained an estimated linear regression equation : Business Performance, which is a comprehensive index, as a dependent variable was significantly related to Customer Focus and Product Liability as regressor variables among 13 evaluation fields by regression analysis.

Background: The hyoid bone is the only non-jointed structure among the skeletal tissues of the head and neck region, and its movement and posture depend on the attached muscle, ligament, and fascia. The location of the hyoid bone is important for airway maintenance, vocalization, chewing, swallowing, breathing, and head and scapular position. In general, the location of the hyoid bone is measured using radiographs and 3D computed tomography, and no studies have reported on clinical measurement methods. Objects: This study was performed to suggest clinical measurement methods for lateral deviation of the hyoid bone and to evaluate their reliability. Methods: In this study, 24 healthy volunteers (12 males, 12 females) in Cheongju-si participated. Two examiners performed the center point test and lateral motion test twice each to measure the lateral displacement of the hyoid bone. The reliability of the center point test was analyzed using intra-class correlation coefficients (ICC), and the reliability of the lateral motion test was analyzed using Cohen’s kappa coefficient. Results: The intra-rater reliability of the center point test was good, and the inter-rater reliability was moderate. The intra- and inter-rater reliability of the lateral motion test showed substantial reliability. Conclusion: Based on these results, the center point test and the lateral motion test can be used as an alternative methods of the measurement of lateral deviation of the hyoid bone for people who have musculoskeletal disorders of the head, neck, and scapula.

The purpose of this study was to evaluate the effect of addition of ethylene glycol, glycerol and sucrose to TCG (Tris, Citric Acid, Glucose, Egg Yolk) and DMSO Frozen. The extender containing Egg yolk concentration (10%, 20%) affects viability and acrosome morphology of rabbit sperm. Sperm viability was then assessed for the freezing extenders TCGD (Tris + Citricacid + Glucose + DMSO), TCGED (Tris + Citricacid + Glucose + Egg yolk + DMSO), TCGGD (Tris + Citricacid + Glucose + Glycerol + DMSO) and TCGSD Tris + Citricacid + Glucose + Sucrose + DMSO) during thawing at 38oC. for 20 seconds, respectively. TCG + 10% egg yolk (viability: 77.0 ± 0.8, NAI: 73.3 ± 0.9) was significantly (sperm viability and normal acrosome interaction (NAI)) higher than TCG + 20% egg yolk (70.7 ± 1.1, 70.0 ± 0.9) in the sperm normalcy analysis according to the yolk concentration. TCGGD (53.4 ± 0.1, 62.3 ± 0.4), TCGSD (61.3 ± 0.0, 67.1 ± 0.1) sperm viability and normal acrosome interaction (NAI) in frozen spermatozoa are TCGD (46.4 ± 2.8 and 56.3 ± 1. 4) and TCGED (23.0 ± 1.1 and 54.6 ± 1.4) extenders was thawed at 38oC for 20 seconds. According to the results from each frozen bulking agent, sperm membrane integrity by hypotonic swelling test (HOST) analysis in TCGGD (59.8 ± 0.7), TCGSD (59.3 ± 0.5) was significantly high compared to other experimental groups (p < 0.05). In conclusion, these results suggested that TCGGD and TCGSD extenders enhance survivability of rabbit sperm after frozen-thawing.