• 대한기계학회논문집
• /
• 제12권6호
• /
• pp.1282-1289
• /
• 1988

본 연구에서는 형태와 특성이 다른 솔레노이드 밸브를 사용한 위치제어 시스 템에 위에서 언급한 두가지 단속적 제어 방법을 적용하여 이들 밸브의 형태와 특성이 시스템의 응답특성에 미치는 영향을 실험적으로 규명하고 실린더 내의 압력 변화에 미 치는 영향도 조사하였다.

• 음성과학
• /
• 제8권1호
• /
• pp.143-157
• /
• 2001

This paper focused on glottal parameters contributing to the perception of loud voices because energy of a voice is not the only effective factor. We used a formant synthesizer to synthesize loud voices. We divided F0 tilt (the tilt of F0 contour), SQ (Speed Quotient), OQ (Open Quotient) and TL (spectral Tilt Level) into three levels to get different combinations with default values for the other synthesizer parameters. Analysis of listening tests indicated that F0 tilt, SQ, OQ and TL in descending order had significant influence on the perception of loud voices. F0 tilt had a far more significant effect than the others. The influence of SQ increased greatly with the exclusion of F0 tilt as a factor. The interaction between parameters was not significant.

• 원예과학기술지
• /
• 제28권6호
• /
• pp.1066-1071
• /
• 2010

자기보고식 설문평가와 컴퓨터 기반 심박변이도(Heart rate variability, HRV) 분석평가를 통해 원예치료가 우울증 환자의 정서개선에 미치는 효과를 알아보았다. 자기보고식 설문 평가는 정신적 스트레스, 신체적 스트레스, 불안, 우울 등 4가지 평가도구를 사용하였다. HRV 분석평가는 standard deviation of the N-N intervals(SDNN), square root of mean squared difference of successive N-N intervals(RMSSD), total power(TP), low-frequency/high-frequency ratio(LF/HF ratio)의 4개 분석지표를 이용하였다. 동일한 병원 소속 우울증 환자 30명을 대상으로 실험을 수행하였다. 이 가운데 실험군 15명을 대상으로 주 1회씩 12회 원예치료 프로그램을 실시하였고, 대조군에는 실시하지 않았다. 그 결과, 원예치료를 실시 한 실험군의 경우 자기보고식 설문평가는 물론 HRV 분석평가에서도 원예치료 후 우울 정서 개선 효과가 확인되었다. 특히 자기보고식 평가에서는 정신적 스트레스, 불안, 우울 척도에서 통계적으로도 유의한 효과가 나타났으며($p$<0.001), HRV 분석평가의 경우 TP 지표에서 통계적 유의성이 확인되었다($p$<0.05). SDNN, RMSSD, LF/HF ratio 지표 역시 눈에 띄게 호전되었으나 통계적 유의성은 없었다. 비록 HRV의 모든 분석지표들이 통계적 유의성을 나타내지는 않았지만, 이 연구를 통해 HRV 측정으로 원예치료 효과를 객관화된 수치로 제시할 수 있는 가능성을 확인하였다. 또한 주관적 평가와 객관적 평가를 도입한 본 실험 결과 원예치료가 우울증 환자의 심리적, 신체적 재활에 효과적임이 입증되었다.

• 한국융합학회논문지
• /
• 제9권1호
• /
• pp.387-392
• /
• 2018

이 연구의 목적은 폐쇄성수면무호흡환자들의 수면단계, AHI, 연령대 간 심박변이도의 통계적 유의성을 결정하는 것이다. 이 연구는 수면무호흡 성인 환자 40명을 대상으로 시간영역 및 주파수 영역에서 심박변이도의 주요 파라메타를 평가하였다. 비 램수면 단계는 3개 그룹 수면무호흡증 환자의 AHI 등급을 비교하여 통계적으로 검증되었다. NN50(p=0.043), pNN50(p=0.044), VLF peak(p=0.022) 및 LF/HF(p=0.028) 매개변수들은 대조군에서 수면무호흡증환자의 R-R 간격에서 통계적으로 유의하였다. 수면무호흡 환자들의 비 램수면(수면2단계)과 램수면 사이의 LF/HF(p=0.045)과 HF power(p=0.0395)파라메타들은 대조군 그룹에서 통계적 유의하였다. 우리는 이 연구에서 폐쇄성 수면무홉증환자들의 AHI, 수면단계 및 연령이 심박변이도 상관관계를 이해하는데 근거를 제시 할 수 있을 것이다.

• Fibers and Polymers
• /
• 제7권4호
• /
• pp.450-456
• /
• 2006

The objectives of this study were to investigate physiological and psychological responses to the rustling sound of Korean traditional silk fabrics and to figure out objective measurements such as sound parameters and mechanical properties determining the human responses. Five different traditional silk fabrics were selected by cluster analysis and their sound characteristics were observed in terms of FFT spectra and some calculated sound parameters including level pressure of total sound (LPT), Zwicker's psychoacoustic parameters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z), and sound color factors such as ${\Delta}L\;and\;{\Delta}f$. As physiological signals, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, pulse volume (PV), heart rate (HR), and skin conductance level (SCL) evoked by the fabric sounds were measured from thirty participants. Also, seven aspects of psychological state including softness, loudness, sharpness, roughness, clearness, highness, and pleasantness were evaluated when each sound was presented. The traditional silk fabric sounds were likely to be felt as soft and pleasant rather than clear and high, which seemed to evoke less change of both LF/HF and SCL indicating a negative sensation than other fabrics previously reported. As fluctuation strength(Z) were higher and bending rigidity (B) values lower, the fabrics tended to be perceived as sounding softer, which resulted in increase of PV changes. The higher LPT was concerned with higher rating for subjective loudness so that HR was more increased. Also, compression linearity (LC) affected subjective pleasantness positively, which caused less changes of HR. Therefore, we concluded that such objective measurements as LPT, fluctuation strength(Z), bending rigidity (B), and compression linearity (LC) were significant factors affecting physiological and psychological responses to the sounds of Korean traditional silk fabrics.

• Journal of Animal Science and Technology
• /
• 제57권3호
• /
• pp.14.1-14.7
• /
• 2015

A feeding trial was carried out to determine the effects of chromium methionine (Cr-Met) chelate and forage level over two years, $1^{st}$ fattening and $2^{nd}$ fattening period on growth parameters, carcass characteristics and blood metabolites of 46 Korean native (Hanwoo, Bos Taurus, $BW=183{\pm}44kg$) steers. Treatments were: 1) Steers in the low forage (LF) group were fed diets that consisted of 60% concentrate and 40% forage; 2) Steers in the high forage (HF) group were fed diets that consisted of 40% concentrate and 60% forage. Following the $1^{st}$ fattening period, steers ($BW=480{\pm}37.6kg$) were randomly assigned to four treatment groups: LF (40 F plus no Cr-Met supplementation in the $2^{nd}$ fattening period), LFCM (40LF plus added 400 ppb of Cr-Met during the $2^{nd}$ fattening period), HF (60 F plus no added Cr-Met during the $2^{nd}$ fattening period) and HFCM (60 F plus added 400 ppb of Cr-Met in the $2^{nd}$ fattening period). Dry matter intake of the treatment diets did not differ during the raising and $1^{th}$ fattening period (P > 0.05). The ADG in the raising period showed no difference between the 40 F and 60 F groups (P > 0.05). Carcass characteristics including rib-eye area and meat yield index were higher in HF than the other treatment groups (P < 0.05). The HF group tended to show a higher (P = 0.08) marbling score than the LF group whereas the HFCM group showed a higher marbling score than the LFCM group (P < 0.05). HDL was higher and LDL lower in groups fed with Cr-Met than in other groups whereas glucose showed the lowest value in HF group (P < 0.05). Triglyceride (TG), Cholesterol, PUN and total protein (TP) were the same among all treatment groups (P > 0.05). The Insulin concentration in the blood was significantly higher for the HFCM group than for the LF, LFCM and HF groups (P < 0.05). It is concluded that supplementation of chromium-methionine chelate could improve meat quality in beef steers.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1998년도 제15회 음성통신 및 신호처리 워크샵(KSCSP 98 15권1호)
• /
• pp.238-241
• /
• 1998

성문파 신호로부터 음원변수들을 추출하는 방법과 그 전 단계에서 역 필터링 방법에 의해 구한 미분성문파 신호로부터 고주파 잡음을 제거하기 위해 음원구간에 따라 필터의 대역폭을 달리함으로서 음원변수 추출과정에서 저역통과 필터에 의해 발생할 수 있는 오차를 최소화하기 위한 선택적 저역통과 필터링 방법을 제안한다. 이 방법은 음원모델중 하나인 LF-model 펄스를 합성하여 필터링 함으로서 그 성능을 비교, 평가하였다.

• The Korean Journal of Pain
• /
• 제19권2호
• /
• pp.202-206
• /
• 2006

Background: Stellate ganglion block (SGB) might be associated with changes in the blood pressure (BP) and heart rate (HR). The heart rate variability (HRV) shows the balance state between sympathetic and parasympathetic activities of the heart. The changes in these parameters of the HRV were studied to evaluate the possible mechanism of SGB in changing the BP. Methods: SGB was performed on 26 patients, using a paratracheal technique at the C6 level, and 8 ml of 1% mepivacaine injected. The success was confirmed by check the Horner's syndrome. The BP, HR and HRV were measured before and 5, 15, 30, 45 and 60 minutes after the SGB. Results: The increases in the BP from the baseline throughout the study period were statistically, but not clinically significant. The HR and LF/HF (low frequency/high frequency) ratio were increased at 5 and 45 min, respectively, after the administration of the SGB. In a comparison of left and right SGB, no significant differences were found in the BP, HR and HRV. A correlation analysis showed that an increased BP was significantly related with the changes in the LF/HF ratio and LF at 15 and 30 minutes, respectively, after the SGB. Dividing the patients into two groups; an increased BP greater and less than 20% of that at the baseline INC and NOT groups, respectively, hoarseness occurred more often in the INC group (P = 0.02). Conclusions: It was concluded that SGB itself does not clinically increase the BP and HR in normal hemodynamic patients. However, the loss of balance between the sympathetic and parasympathetic nerve system, attenuation of the baroreceptor reflex and hoarseness are minor causes of the increase in the BP following SGB; therefore, further studies will be required.

• 융합신호처리학회논문지
• /
• 제6권4호
• /
• pp.191-197
• /
• 2005

2족 보행을 특징으로 하는 인간형 로봇은 구동해야할 관절의 수가 매우 많으며, 로봇의 보행 상태 등을 인식하기 위하여 다양한 센서의 활용이 필요하다. 본 논문에서는 21개의 RC 서보 모터를 사용한 소형의 2족 보행 로봇의 제어기의 구조를 제안하고 구현한다. 제안된 제어기는 호스트 PC와 DSP를 사용한 주 제어기, 그리고 FPGA를 사용한 보조 제어기의 계층 구조를 갖는다. 호스트 PC에서는 보폭, 보행 시간 등과 같은 보행 파라미터에 따른 로봇의 보행 데이터를 생성하여 주 제어기로 전송하고, TI사에서 제어용으로 출시된 DSP 칩인 TMS320LF2407A를 사용하여 구현된 주 제어기에서는 보조 제어기를 통하여 21개의 RC 서보 모터를 구동한다. 또한 주 제어기와 2축 가속도 센서를 인터페이스하여 보행 바닥면의 경사도에 따른 균형잡기 실험과 기울어진 바닥면의 기울기를 검출하여 경사면 보행이 가능함을 보인다.

• Journal of Korean Neurosurgical Society
• /
• 제64권6호
• /
• pp.901-912
• /
• 2021

Objective : In the cervical spine, many surgical procedures have been developed to achieve optimal results for various disorders, including degenerative diseases, traumatic injury, and tumor. In this study, we report our experience and follow-up results with a new surgical technique for cervical spine entitled posterior floating laminotomy (PFL) in comparison with conventional laminectomy and fusion (LF). Methods : Data for 85 patients who underwent conventional LF (n=66) or PFL (n=19) for cervical spine disorders between 2012 and 2019 were analyzed. Radiological parameters, including cervical lordosis (CL), T1 slope (T1S), segmental lordosis (SL), and C2-7 sagittal vertical axis (SVA), were measured with lateral spine X-rays. Functional outcomes, comprising the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and visual analog scale (VAS) scores, were also measured. For the patients who underwent PFL, postoperative magnetic resonance image (MRI) was performed in a month after the surgery, and the degree of decompression was evaluated at the T2-weighted axial image, and postoperative computed tomography (CT) was conducted immediately and 1 year after the operation to evaluate the gutter fusion. Results : There was no difference in CL, T1S, SL, and C2-7 SVA between the groups but there was a difference in the preoperative and postoperative SL angles. The mean difference in the preoperative SL angle compared with that at the last follow-up was -0.3° after conventional LF and 4.7° after PFL (p=0.04), respectively. mJOA, NDI, and VAS scores showed significant improvements (p<0.05) during follow-up in both groups. In the PFL group, postoperative MRI showed sufficient decompression and postoperative CT revealed gutter fusion at 1 year after the operation. Conclusion : PFL is a safe surgical method which can preserve postoperative CL and achieve good clinical outcomes.