• 말소리와 음성과학
• /
• 제6권3호
• /
• pp.101-108
• /
• 2014

This study investigates the relation among pitch range differences, speech rate and realization of stress. To identify the realization of the stress, vowel formants and durational differences of stressed and unstressed vowels are measured. The Korean learners were asked to read a textbook passage which includes nine sentences. The major results indicate that: (1) Korean speakers' pitch range is less than 50% of the native speakers; (2) There is a significantly negative relation between high-low pitch range and speech rate; (3) The vowel qualities and durations of the stressed and unstressed vowels are related to the speech rate. But these are not related to the high-low pitch range.

• 소성∙가공
• /
• 제20권8호
• /
• pp.595-600
• /
• 2011

This paper investigates the effect of strain rate on the anisotropic deformation behavior of advanced high strength steel sheets. Uniaxial tensile tests were carried out on TRIP590 and DP780 steel sheets at strain rates ranging from 0.001/sec to 100/sec to determine yield stresses and r-values at various loading angles from the reference rolling direction. R-values were determined by the digital image correlation technique. Hill48 and Yld2000-2d yield functions were tested for their capability to describe the plastic deformation anisotropy of the materials. Initial yield loci were constructed using the Yld2000-2d yield function, which adequately described the anisotropic behavior of the materials. The shape of the initial yield loci was found to change with different strain rate, and the anisotropic behavior decreased with increasing strain rate.

• Journal of the Korean Data and Information Science Society
• /
• 제25권6호
• /
• pp.1531-1538
• /
• 2014

The causes of cancer are diverse, complex, and only partially understood. Many factors including health behaviors, socioeconomic environments and geographical locations can directly damage genes or combine with existing genetic faults within cells to cause cancerous mutations. Collecting the cancer data and reporting the statistics, therefore, are important to help identify health trends and establish normal health changes in geographical areas. In this article, we analyzed cancer data and demon-strated how spatial patterns of the age-standardized rate and health indicators can be examined visually and simultaneously using linked micromap plots. As a result of data analysis, the age-standardized rate has positive correlativity with thyroid and breast cancer, but the rate has negative correlativity with smoking and drinking. In addition, the regions with high age-standardized rate are located in southwest and the areas of high population density while the standardized mortality ratio is higher in southwest and northeast where there are lots of rural areas.

• 한국산학기술학회논문지
• /
• 제9권6호
• /
• pp.1673-1677
• /
• 2008

본 논문은 UHF 대역의 RFID(Radio frequency identification) 태그의 인식률에 대한 연구이다. RFID 태그 안테나가 고유전율을 가지는 제품에 부착되는 경우에 태그 안테나의 성능 변화 때문에 인식률 저하 문제가 발생 한다. 본 연구에서는 상용화 된 태그 안테나를 도자기 표면에 부착하였을 때 안테나의 전기적인 특성 변화를 살펴보았고 태그 안테나를 튜닝한 후 태그 인식률이 현저히 개선됨을 보였다.

• 통합자연과학논문집
• /
• 제14권4호
• /
• pp.155-158
• /
• 2021

To study the effects of hormones and neurotransmitters, zebrafish (Danio rerio) are a great substitute for water fleas (Daphnia). The zebrafish is an ideal vertebrate model because it has a transparent embryonic stage. It is easy to get consistent heart rate measurements in embryonic zebrafish when treating them with hormones and neurotransmitters. To observe the heart rate, two to three embryonic zebrafish are anesthetized with MS-222 and then transferred to a glass slide specifically designed for heart observation and easy application of various chemicals. After the heartbeats are counted for 2 minutes, apply either 100 µM epinephrine or 100 µM acetylcholine to the zebrafish. Wait 5, 10, and 20 minutes and count the heartbeats at each time point. All procedures are repeated three times. The final results are averaged and analyzed by using statistical methods. The above method which we have developed is practical enough for high school students to measure the heart rate in zebrafish under various conditions and to analyze the data set.

• 한국음향학회지
• /
• 제23권1호
• /
• pp.54-60
• /
• 2004

44.1 kHz 샘플링 비율의 표준 CD음질의 오디오 신호를 인터넷 상에서 전송 및 분배하기 위해서 네트워크 대역폭과 저장 공간의 제한점을 고려해야 한다. 이러한 제한은 오디오 신호의 샘플링 비율을 낮추거나 MP3와 같은 오디오 데이터 압축 기법을 이용하여 해결할 수 있지만, 공통적으로 고 주파수 (High frequency) 대역의 정보가 손실 된다는 문제가 발생한다. 이러한 고 주파수 손실은 결국 저 샘플링 비율의 오디오 신호를 생성하게 되며 표준 CD음질을 가지는 오디오 신호보다 제한된 저 주파수 대역만을 재생할 수 있게 된다. 일반적으로 오디오 신호의 고주파 성분은 위치정보와 명료도, 재생 환경 등에 대한 음의 풍부한 정보를 제공한다. 본 논문의 목적은 LMS 적응 필터링과 DWT 분석/합성을 이용하여 저 샘플링 비율을 가지는 오디오 신호로부터 고 주파수 대역의 정보를 효과적으로 추정하는 것이다. 제안된 알고리즘은 DWT 영역에서 LMS 적응 알고리즘을 이용하여 고 주파수 정보를 추정하고 DWT 합성을 이용하여 고 주파수 정보가 강화된 고음질의 오디오 신호를 재생한다. 제안된 알고리즘의 성능 평가를 위해 실제 음성신호와 음악 신호를 이용하여 컴퓨터 모의 실험과 청취 평가를 수행하여 기존 알고리즘과 비교하였으며, 실험 결과 제안된 알고리즘의 우수성을 확인하였다.

• 한국자동차공학회논문집
• /
• 제18권1호
• /
• pp.127-130
• /
• 2010

This paper deals with the formability of DP590 steel considering the strain rate. The strain hardening coefficient, elongation and r-value were obtained from the static and dynamic tensile test. As strain rate increases from static to 100/s, the strain hardening coefficient and the uniform elongation decrease and the elongation at fracture and r-value decrease to 0.1/s and increase again to 100/s. The high speed forming limit tests with hemi-spherical punch were carried out using the high speed crash testing machine and high speed forming jig. The high speed forming limit of DP590(order of $10^2$/s) decreases compared to the static forming limit(order of $10^{-3}$/s) and the forming limit band in high speed forming test is narrower than that in the static forming test. This tendency may be due to the development of brittleness with increase of stain rate.

• 대한기계학회논문집A
• /
• 제39권6호
• /
• pp.611-615
• /
• 2015

비행기 방어용 대공포는 저고도 방어체계로 사용되고 있으며, 방어능력 극대화를 위해 대부분 고발사율 대공포를 두개 이상 탑재하여 교전 시 명중률을 높이고 있다. 고 발사율 대공포의 경우, 포열진동 및 탄의 불균형 분산은 정확한 조준사격 및 명중률에 아주 결정적인 영향을 미치게 된다. 따라서 사격 진동 및 충격량을 감소하는 구조는 대공포 체계에서는 주요 설계 대상이다. 본 연구에서는 차량의 현가장치 특성에 따라 고발사율 대공포 체계에서 발사시스템의 진동충격으로부터 차단하는 능력을 향상시키고, Recurdyn 과 Adams 를 이용한 동적 거동해석과 실 사격 시험결과를 비교하여 명중률에 영향을 미치는 현가 형태, 위치 및 수량에 따른 체계 자세 흔들림을 예측하였다. 본 연구를 통하여 대공포에 적합한 현가장치와 포 스프링 등과 같은 구성품을 선정할 수 있는 기초연구를 수행하였다.

• 대한기계학회논문집B
• /
• 제26권3호
• /
• pp.448-457
• /
• 2002

Heat treatment such as quenching of a high-temperature cylinder is being used on steel to produce high strength levels. Especially, the mist cooling with the high and uniform surface heat flux rate s expected to contribute for better products. The experimental mist cooling curve is produced for better understanding, and two distinct heat transfer regions are recognized from the cooling curve produced. It is shown that the liquid film evaporation dominated region follows the film boiling-dominated region as decreasing the temperature of test cylinder by mist flow. Based on the intuitive view from some previous investigations, a simplified model with some assumptions is introduced to explain the mist cooling curve, and it is shown that the estimation agrees well with our experimental data. In the meanwhile, it is known that the wetting temperature, at which surface heat flux rate is a maximum, increases with mass flow rate ratio of water to air ($\varkappa$ < 10). However, based on our experimental data, it is explained that there exists a critical mass flow rate ratio, at which the wetting temperature is maximum, in the range of 3 < $\varkappa$ < 130. Also, it is described that despite of the same value of $\varkappa$, the wetting temperature may increase with mist velocity.

• Asian-Australasian Journal of Animal Sciences
• /
• 제18권8호
• /
• pp.1116-1124
• /
• 2005

The influence of fiber content of hay (low-fiber 47% NDF and high-fiber 62% NDF of DM) and concentrate level (high 50% and low 20% of ration DM) on chewing activity, passage rate and nutrient digestibility were tested on four restrict-fed (11.1 to 13.7 kg DM/d) Holstein cows in late lactation. Aspects of ruminal fermentation and digesta particle size distribution were also investigated on two ruminally cannulated (100 mm i.d.) cows of the same group of animals. All digestion parameters studied were more affected by the fiber content of the hay and its ratio to non structural carbohydrates than by the concentrate level. Giving a diet of high-fiber (62% NDF) hay and low concentrate level (20%) increased chewing activity but decreased solid passage rate and total digestibility of nutrients due to a limited availability of fermentable OM in the late cut fiber rich hay. A supplementation of high-fiber hay with 50% concentrate in the diet seems to improve the ruminal digestion of cell contents, whilst a depression of the ruminal fiber digestibility was not completely avoided. Giving a diet of low-fiber (47% NDF) hay and high concentrate level (50%) reduced markedly the chewing and rumination activity, affected negatively the rumen conditions and, consequently, the ruminal digestion of fiber. A reduction of the concentrate level from 50 to 20% in the diet of low-fiber hay improved the rumen conditions as reflected by an increase of the ruminal solid passage rate and of fiber digestibility and in a decrease of the concentration of large particles and of the mean particle size of the rumen digesta and of the faeces. Generally, it can be summarised that, (i) concentrate supplementation is not a strategy to overcome limitations of low quality (fiber-rich) hay, and (ii) increase of the roughage quality is an effective strategy in ruminant nutrition, especially when concentrate availability for ruminants is limited.