• 폴리머
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• 제26권6호
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• pp.812-820
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• 2002

본 연구에서는 나노입자인 카본블랙을 고분자에 분산시킨 복합체를 각각 용액혼합과 용융혼합을 이용하여 positive temperature coefficient (PTC) 특성을 연구하였다. 전도성 나노입자인 카본블랙과 고분자 복합체의 저항 통전 (threshold)은 용융혼합하였을 때 카본블랙의 함량이 35wt% 이상에서 나타났으며. 용액혼합에서는 카본블랙 함량이 40 wt% 이상에서 나타났다. Ethyl-one vinylacetate copolymer (EVA)의 경우, 온도의 변화에 따라서 저항이 서서히 증가하다가 용융점 근처에서 극대값을 나타내었지만, high density polyethylene (HDPE)의 경우는 저항이 온도의 변화에 따라 일정하다가 용융점 근처에서 증가하기 시작하여 용융점에서 극대값을 나타내었다. 통전 후의 낮은 저항과, scanning electron microscopy (SEM)으로 관찰한 결과로부터 전도성 나노입자의 카본블랙 분산방법에서 용액혼합의 분산 정도가 용융혼합 못지않게 나타났다. PTC 소재에 전류인가시 큐리온도에서 1차적으로 저항이 증가하였으며, 고분자의 용융점에서 2차적으로 트립온도가 될 때까지 저항이 증가하다가 트립온도 이후에는 저항이 일정하게 유지됨을 알 수 있었다.

• 한국정보통신학회논문지
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• 제13권10호
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• pp.2205-2210
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• 2009

본 논문에서 제안하는 잡음제거 방법은 hard 임계치 방법의 문제점을 개선한 제로점의 탄젠트 곡선 보간에 의한 잡음제거 기술이다. 자연계에서 관측되는 대기 전기변동량과 같은 신호의 시간적 변동량이나 가상현실을 이용하여 추출한사람의 빠른 움직임의 동작 곡선 등은 실제로 복잡하다. 따라서 이러한 신호의 관측파형에 대하여 변곡점에 대한 특징을 정확히 결정하는 것이 매우 중요하다. 특히 자연계의 측정 신호는 잡음이 포함되어 있어서 잡음을 제거하고 특징을 추출하는 것이 필요하다. 본 논문에서 제안한 새로운 방식에 의하여 잡음을 제거하고 변곡점을 추출하며 종래의 방식인 hard 임계치에 비하여 잡음지수가 5인 경우의 noise II 변곡점 신호에 대하여 SNR이 3.4dB 개선된 결과를 얻을 수 있음을 보였다.

• 대한임상전기생리학회지
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• 제8권1호
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• pp.23-29
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• 2010

Purpose : This study is to offer clinical primary data that examines the change of imaging structure and the quantitative evaluation of muscle activity on myofascial trigger points. This study examines neuromuscular physiological characteristic by comparing the differences in physical findings, pressure pain threshold, imaging, and electrophysiological characteristics in latent and active myofascial trigger points muscle and normal muscle through the following experimental procedures. Methods : The participants for the study were thirty-three adults in their twenties. We divided three groups into normal, latent and active myofascial trigger points groups by physical findings. We analyzed the results of measured pressure pain, threshold for pain, ultrasound imaging perform for structure characteristic of muscle, surface EMG according to type of muscle contraction for function of muscle contraction. Results : Significant differences were indicated in pressure pain threshold (p<0.05). Significant differences were discovered in the ultrasound imaging analysis. There were increases in muscle Echogenicity white area index (p<0.001). There were significant differences that decrease in %MVIC (p<0.05), increase in MDF (p<0.05). Conclusion : From these results, active rnyotascial trigger points muscle showed quality deterioration on ultrasound imaging and decreased function of muscle contraction, increased motor unit action potential of II type fiber, and electrophysiologically. Imaging structure and neuromuscular physiological characteristic can be diagnostic and quantitative analytical techniques for myofascial pain syndrome and a primary factor that reflected in physical therapy intervention.

• 한국인터넷방송통신학회논문지
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• 제15권3호
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• pp.107-112
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• 2015

스마트폰과 많은 무선단말기들이 이동성의 특성상 AP간 이동하게 되어 무선단말들과 AP(Access Point)간 많은 호 절체가 이루어지게 된다. AP에서 각 무선단말기마다 처리되는 호 처리는 상대적으로 많은 무선트랙픽을 유발하여 무선대역의 효율적인 활용을 저해하는 요인이 되고 있다. 따라서 본 논문에서는 무선단말기와 AP간의 트래픽 발생요인이 되고 있는 AP간 호 절체 트래픽양을 줄이기 위해서 무선단말기에 수신되는 AP들의 전력세기임계치와 임계타이머를 사용하여 AP에서 효과적으로 무선트랙픽을 활용할 수 있는 방안을 제안하였다. 제안된 방식과 기존의 방식을 시뮬레이션을 통하여 AP에서 처리하는 무선트래픽 양이 개선되어 전체적으로 무선대역의 활용을 효율적으로 할 수 있었다.

• 한국대기환경학회지
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• 제15권5호
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• pp.599-611
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• 1999

Now that the plume of point source was suspected to have strong impact on visibility impairment in Pusan, we evaluated visibility impairment impact of the pulme from Pusan Thermo Electric Power Plant in Pusan. Level-1 and-2 analyses were carried out using VISCREEN(Visual Impact Screen model). The emission rates for this Pusan Thermo Electric Power Plant was projected to be 116g/s of nitrogen oxides(as $NO_2$). The source fails the level-1 test with a Plume perceptibility(ΔE) of 30, nearly 15 times the screeing threshold. To characterize worstcase meteorological conditions for level-2 screening, we obtained meteorological data from Mar., 1996 to Feb., 1997 of Pusan Thermo Electric Power Plant. The source fails the level-2 test with a ΔE of 17, nearly 8.5 times the screening threshold. These analyses indicated that adverse visibility impairment could not be ruled out. Therefore a Level-3 analysis was performed using PLUVUE II(Plume Visibility model). As a result, maximum reduction of visual range for 0900LST in winter was 0.9%. Visual impact of the plume from vast point source was judged to be considerable in terms of background visibility of urban area.

• International Journal of Contents
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• 제7권2호
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• pp.59-63
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• 2011

The aim of our study was to evaluate the immediate effects of an 830-nm Aluminium gallium arsenide (GaAlAs) laser, by examining the changes, in pressure-pain threshold (PPT) and tenderness at 3 kg of the myofascial trigger point (MTrP) of the upper trapezius muscle in visual display terminal (VDT) workers in comparison with placebo treatment. Thirty VDT workers (13 males, 17 females) with complaints of upper trapezius muscle were recruited. All participants were given either active GaAlAs laser (830 nm wavelength, 450 mW, 9 J at point) or placebo GaAlAs laser, according to the double-blinded and placebo-controlled trial. Both active and placebo low-level laser therapy (LLLT) treatments showed no significant effect on PPT and tenderness at 3 kg. These results suggest that a higher dosage may be necessary to produce immediate effects when applying LLLT to the MTrP of relatively large muscles such as the upper trapezius muscle.

• 대한한방내과학회지
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• 제33권4호
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• pp.498-510
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• 2012

Objectives : This study was designed to find out whether there is a correlation between qi-stagnation score and pressure pain threshold (PPT) on acupuncture point $CV_{17}$ in burning mouth syndrome (BMS) patients. Methods : Thirty BMS patients who newly visited Oral Disease Clinic at the Kyung Hee University Korean Medicine Hospital were surveyed. The subjects were evaluated on age, illness duration, sex, self-assessed severity of BMS, qi-stagnation score, and PPT on 3 acupuncture points ($CV_{17}$, Rt. $SP_9$, Lt. $SP_9$). Results : There was significant correlation between age and PPT on $CV_{17}$ (p=0.005). Therefore, partial correlation analysis with age as control variable was done, and the result showed significant correlation between qi-stagnation score and PPT on $CV_{17}$ (p=0.001). Qi-stagnation diagnostic point by PPT on $CV_{17}$ was suggested as 3.8056 $kg/cm^2$ based on the fact that diagnostic score is 28.50 in the qi-stagnation questionnaire. Furthermore, considering that PPT is effected by age, we could attain qi-stagnation diagnostic equation of PPT on $CV_{17}$, that is suggested as $0.047{\times}(age)+0.848kg/cm^2$. PPT of 3 acupuncture points ($CV_{17}$, Rt. $SP_9$, Lt. $SP_9$) was compared, and the result showed that PPT was significantly lower on $CV_{17}$ (w/Rt $SP_9$: p=0.022, w/Lt. $SP_9$: p=0.012). Also, significance and correlation coefficient with qi-stagnation were higher on $CV_{17}$ (p<0.001, r=-0.620) than Rt. $SP_9$ (p=0.023, r=-0.413) or Lt. $SP_9$ (p=0.014, r=-0.444). Conclusions : The result of this study suggested that PPT on $CV_{17}$, measured quantitatively by algometer, had a strong correlation with qi-stagnation score in BMS patients. Therefore, the study showed that $CV_{17}$ can be a useful acupuncture point in diagnosing qi-stagnation by measuring PPT in BMS patients.

• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.969-974
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• 1998

The effects of $La_2O_3$on the microstructure and electrical characteristics of Pr-based ZnO varistors were investigated. The average grain size increased in the range of 21.9~56.3$\mu$ m with increasing $La_2O_3$additive content(0.0~2.0 mol%). La was, of course grain boundary, largely segregated at the nodal point. As $La_2O_3$additive content increases, threshold voltage and nonlinear coefficient decreased and leakage current increased. In particular, 2.0 mol% $La_2O_3$-added varistor exhibited low threshold voltage 17.0V/mm and nonlinear coefficient of about 6. Based on these results, this varistor can be said to be used as low-voltage varistor, if nonlinear coefficient is somewhat improved forward.

• 정보보호학회논문지
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• 제7권1호
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• pp.15-32
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• 1997

본 논문에서는 스트림 암호 시스템에서 사용이 되는 LFSR 을 이용한 이진 수열 발생기중 하나인 Threshold 발생기에 대한 광학적 구현 방법을 새로이 제안하였다. 광학적 구현을 위하여 LCD를 이용하므로서 LFSR 및 Mod 덧셈 연산을 위한 각 비트 값을 표현, 2차원 처리가 가능하게 하였다. Thredshold 발생기의 LFSR기능은 Shdow Casting 기법을 이용하여, 또한 XOR 연산 및 내적 계산을 위한 MOD덧셈 연산은 LCD 가 갖고 있는 편광 특성을 이용하여 광학적으로 구현하였다. 특히 본 논문에서는 Mod 2 덧셈 연산을 위한 새로운 광학적 구현 방법인 RSPM 을 제안하므로서 연산 결과 값 측정과 LCD 상의 데이타 값 표현 과정을 제외한 전 부분을 완전한 광학적 방법으로 처리가 가능하게 하였다. 본 논문에서 제안한 광 Threshold 암호 시스템은 기존의 전자적인 H/W 구현 방법에서 문제가 되어오던 Tapping Point의 개수에 대한 한계성을 극복할 수 있는 장점을 지니고 있으며, 또한 2차원 데이타인 영상용 암호화 시스템의 광학적 구현에 그 응용이 가능하다.

• The Journal of Korean Physical Therapy
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• 제6권1호
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• pp.85-93
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• 1994

The purposes of this study were 1) to examine the effects of microcurrent electrical neuromuscular stimulation 2) to compare surface electrode with needle electrode at somatic acupuncture points on experimental pain threshold measured at the distal end of the radius 3) to determine the changes in effect over time. A total of sixty healthy adult male and female subjects were assigned randomly to one of two experimental group or to a control group. Group 1(n=20) received MENS(Microcurrent Electrical Neuromuscular Stimulation) with surface electrode. Group 2(n=20) received HENS with needle electrode. Group 3(n=20) received no MENS. It measured experimental pain threshold at the wrist on pretreatment, 0 min after treatment. 15 min after treatment, 30 min after treatment in two experimental group. The results were as follows: 1. Experimental pain thresholds were higher in males than females(P<0.01). 2. Only the experimental group exhibited a significant increased in pain threshold after MENS treatment(P<0.05). 3. Surface electrode group increased significant pain threshold 0 min, 15 min after treatment, but greatly decrease 30 min after treatment. 4. Needle electrode group increased significant pain threshold 0 min, 15 min after treatment, but decrease 30 min after treatment. The results suggest that MENS applied to appropriate somatic acupuncture point can increase pain threshold. Further research is needed to assess the effects of greatly variety intensity of MENS of pain sufferes.