• Investigative Magnetic Resonance Imaging
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• 제20권4호
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• pp.207-214
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• 2016

Purpose: The purpose of this study was to investigate the effect of the number of measurement points on the calculation of transverse relaxation time (T2) with a focus on muscle T2. Materials and Methods: This study assumed that muscle T2 was comprised of a single component. Two phantom types were measured, 1 each for long ("phantom") and short T2 ("polyvinyl alcohol gel"). Right calf muscle T2 measurements were conducted in 9 healthy male volunteers using multiple-spin-echo magnetic resonance imaging. For phantoms and muscle (medial gastrocnemius), 5 regions of interests were selected. All region of interest values were expressed as the mean ${\pm}$ standard deviation. The T2 effective signal-ratio characteristics were used as an index to evaluate the magnetic resonance image quality for the calculation of T2 from T2-weighted images. The T2 accuracy was evaluated to determine the T2 reproducibility and the goodness-of-fit from the probability Q. Results: For the phantom and polyvinyl alcohol gel, the standard deviation of the magnetic resonance image signal at each echo time was narrow and mono-exponential, which caused large variations in the muscle T2 decay curves. The T2 effective signal-ratio change varied with T2, with the greatest decreases apparent for a short T2. There were no significant differences in T2 reproducibility when > 3 measurement points were used. There were no significant differences in goodness-of-fit when > 6 measurement points were used. Although the measurement point evaluations were stable when > 3 measurement points were used, calculation of T2 using 4 measurement points had the highest accuracy according to the goodness-of-fit. Even if the number of measurement points was increased, there was little improvement in the probability Q. Conclusion: Four measurement points gave excellent reproducibility and goodness-of-fit when muscle T2 was considered mono-exponential.

• Journal of Nutrition and Health
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• 제35권3호
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• pp.368-379
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• 2002

This study investigated the correlations among the health consciousness, nutrition knowledge, dietary habits and nutrition attitudes of school teachers. The subjects of this study were 75 male and 152 female leachers in elementary and middle schools in Masan city. The survey was conducted by using a questionnaire. Even though the average body mass index (BMI) and the obesity index were normal in both male and female subjects, 33.3% of the male subjects were overweight/obese, while 18.5% of the female subjects were underweight, according to the obesity index. The food components of most concern during mealtime were (in order of importance) salt, MSG and cholesterol by male subjects, and salt, fat and MSG by female subjects. The subjects considered self-relaxation as the most important factor in maintaining optimal health status, followed by resting, bathing or use ova sauna, moderation in diet, exercise, decreasing alcohol intake, and no smoking. Newspapers/magazines and TV/radio were the primary sources of nutrition and health information of the subjects. As the degree of health consciousness increased, scores of the dietary habits and nutrition attitudes increased. Nutrition knowledge scores and nutrition altitudes scores increased with subjects'increased level of perception of the importance of acquiring nutrition knowledge and nutrition information. There was a highly significant correlation between the degree of health consciousness and dietary habit score (${\gamma}$ : 0.3, p<0.001). The degree of health consciousness was also significantly correlated (${\gamma}$=0.6, p<0.001) with nutrition attitudes scores. But the correlation between the degree of health consciousness and nutrition knowledge was not statistically significant. The degree of the perception of the importance of nutrition knowledge showed a positive correlation with nutrition attitude (${\gamma}$:0.4, p<0.001) and dietary habit (${\gamma}$:0.3, p<0.001). The degree of perception about the importance of nutrition knowledge and nutrition information was positively correlated with nutrition knowledge (${\gamma}$:0.2, p<0.001) and nutrition attitudes (${\gamma}$:0.3, p<0.001).

• 한국콘텐츠학회논문지
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• 제11권4호
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• pp.42-50
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• 2011

생체신호인 뇌파를 이용하여 이러닝 학습자의 학습태도를 파악하고 그에 따른 적절한 피드백을 제공하여 학습자의 학습효율을 극대화하려는 연구의 일환으로 여대생을 대상으로 학습자의 학습태도와 뇌파를 분석하여 이들의 상관관계를 밝혀보고자 한다. 학습자가 학습에 집중하는 태도와 그렇지 않은 태도에 대해 뇌파의 파워 스펙트럼을 추출하여 학습자의 뇌파가 어떻게 반응하는지에 중점을 두어 연구하였다. 학습에 집중하는 태도의 대조군으로 산만한 태도와 눈감은 태도를 설정하여 실험을 진행하였다. 학습에 집중하는 태도에서는 집중도가 산만한 태도에 비하여 높게 나타나고 이완지표는 낮게 나타나며, 클릭과 눈굴림과 같은 산만한 태도에서는 주의지표와 잡파 비율이 높게 나왔다. 특히, 눈을 감았을 때는 알파 세타 비율이 1이하로 나타나 눈을 뜬 다른 상태와 뚜렷이 구분되었다.

• 한국지반환경공학회 논문집
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• 제4권2호
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• pp.77-91
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• 2003

연속체 해석을 위한 암반거동 모델로서 널리 이용되고 있는 Hoek-Brown 파괴기준은 1980년도에 발표된 이후 수차례의 수정 보완을 거쳐 1994년에 발표된 Generalized Hoek-Brown 파괴기준식을 토대로 현재 암반을 대상으로 한 지반구조물 해석에 많이 적용되고 있다. 그러나 지반구조물 수치해석시 Hoek-Brown 파괴기준의 적용은 일반적으로 등가의 Mohr-Coulomb 전단강도정수를 산정하여 간접적으로 이용하게 되는데, 이때 등가의 암반 전단강도정수를 암반내 주응력 분포와 상관없이 일정 상수로 적용함으로서 Hoek-Brown 파괴기준의 비선형성을 고려하지 못하는 단점이 있다. 따라서 본 연구에서는 암반사면의 안정성 평가를 위한 연속체 해석시 Hoek-Brown 파괴기준의 비선형성을 고려할 수 있는 해석기법을 검토하고, 수치해석기법에 의한 사면안정검토에 주로 이용되고 있는 강도감소법을 이용하여 암반사면의 안정성을 정량적으로 평가하고자 하였다. 특히 최근에 발표된 수정 Hoek-Brown 파괴기준을 토대로 수정된 등가 Mohr-Coulomb 강도정수 산정법과 사면굴착시 발파 및 응력이완에 의한 암반 교란/손상을 고려한 암반교란상수(Disturbance Factor) D을 이용하여 안정해석을 수행하였다.

• 융합정보논문지
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• 제11권3호
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• pp.250-260
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• 2021

본 연구는 투척 선수의 하지 훈련 자세를 이용한 전신진동 운동 훈련 시 근육 변화와 대칭 지수를 살펴보는데 목적이 있다. 20 대 10 명(남성 6명 여성 4명, 나이:24.60±0.92세, 신장:177.90±7.40cm, 체중:92.90±22.97kg)의 투척 선수를 대상으로 스쿼트, 카프 레이즈, 런지 동작으로 하지 훈련 자세를 이용한 전신진동 운동 훈련을 실시하였다. 하지 관절 근육(대퇴이두근, 비복근 외측, 비복근 내측, 대퇴직근, 전경골근, 외측광근, 내측광근) 부위를 Tensiomyography(TMG) 변인 Time Delay(Td), Time Contraction(Tc), Time Sustain(Ts), Time Relaxation(Tr), Displacement Maximumal(Dm)을 통해 측정하여 근 활성도, 근 피로도, 좌우 대칭을 Wilconxon의 순위 검사로 비교하였고, 이때 유의수준은 α= .05로 분석하였다. 연구결과는 Td에서 왼쪽 RF, VL, 오른쪽 VM(p<.05), Tc에서는 VM(p<.05), Ts 에서는 GM(p<.05), Tr 에서는 왼쪽 RF, 오른쪽 TA(p<.05)에서 변화를 보였다. 따라서 스쿼트, 카프 레이즈, 런지 동작의 전신진동 운동 훈련이 근 수축 변화가 있는 효과적인 운동임을 입증되었고, 좌·우 근육 대칭으로 코어의 안정성이 확보되었다. 이로 인해 전신진동운동은 재활훈련 긍정적인 영향을 미칠 것이고, 경기력 향상을 도모할 수 있을 것으로 판단된다.

• 한국정보전자통신기술학회논문지
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• 제16권5호
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• pp.272-278
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• 2023

사람의 인지기능을 구성하는 중요한 요소인 주의력은 감각기관을 통한 다양한 자극에서 필요한 자극에만 의식을 집중하는 중요한 인지기능이다. 다양한 환경 요건이 주의력에 영향을 미친다는 다양한 연구 결과가 있으나 피부에 직접 냉각요법을 적용하는 것이 주의력에 영향을 미치는 바는 많이 연구되지 않았다. 36명의 피평가자를 대상으로 학습 및 휴식 활동 중 냉동요법 적용 시점 및 여부에 따른 주의력의 차이를 살펴보았다. 시각적 주의력 평가도구인 FAIR 주의력 검사를 실시하였으며 해당 평가도구의 주의력 지수인 능력지수, 통제지수, 지속성지수 결과에 대한 통계적 분석을 실시하였다. 휴식 활동을 수행한 피평가자 사이에서는 냉동요법의 적용이 모든 하위지수에 영향을 미치지 않는 것으로 나타났다. 학습 활동을 수행한 피평가자 사이에서는 사전 냉동요법을 적용한 집단(P=469.0, C=435.4))과 사후 냉동요법을 적용한 집단(P=457.4, C=425.4)이 냉동요법을 실시하지 않은 집단(P=335.8, C=301.7)에 비해 능력지수와 지속성지수가 높게 나타났다. 이러한 결과로부터 냉동요법이 제한적으로나마 주의력의 수준을 유지 시켜주고, 주의를 환기해 준다는 결론 도출할 수 있다.

• 대한통합의학회지
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• 제9권4호
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• pp.271-281
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• 2021

Purpose : This study aimed to apply muscle relaxation exercise and ultrasound therapy as an effective treatment method for tension headache patients by comparatively analyzing the muscle mechanical properties, neck disorder index, and headache impact test. Method : The subjects were classified into three groups based on the intervention received: the therapeutic ultrasound (n=15, group I), placebo therapeutic ultrasound combined with the suboccipital release (n=15, group II), and therapeutic ultrasound combined with suboccipital release (n=15, group III) groups. The intragroup and intergroup differences in muscle mechanical properties, neck disability index, and headache impact test were compared and analyzed. Result : The comparison and analyses of the changes in muscle tone and post hoc analysis revealed statistically significant intragroup decreases in the suboccipitalis and upper trapezius in groups I and III. Furthermore, statistically significant intergroup differences in the upper trapezius with a greater change in group III than in group II and suboccipitalis with greater changes in group III than in groups I and II were observed. The comparison and analyses of the changes in muscle stiffness and post hoc analysis revealed statistically significant intragroup decreases in the upper trapezius in group I and suboccipitalis in group III. Moreover, statistically significant intergroup differences in both muscles with greater changes in group III than in group II for both cases were observed. The comparison and analyses of the changes in the neck disability index and post hoc analysis revealed statistically significant intragroup decreases in all three groups and statistically significant intergroup differences with greater changes in group III than in groups I and II. The comparison and analyses of the changes in the headache impact test and post hoc analysis revealed statistically significant intragroup decreases in all three groups and a statistically significant intergroup difference with greater changes in group III than in groups I and II. Conclusion : The therapeutic ultrasound and suboccipital muscle release exercise effectively increased the flexibility of the muscles around the cervical vertebrae and reduced muscle tension and stiffness in tension-type headache patients.

• 국제물리치료학회지
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• 제9권4호
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• pp.1683-1686
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• 2018

Low back pain (LBP) is the most common reason for seeking physical therapy (PT) care. Recent studies suggest that axial loading can have a positive impact on the intervertebral disc by improving its tensile strength. Further, whole body vibration (WBV) appears to improve spinal muscle relaxation. Therefore, this case study describes the use of axial loading using a mini-trampoline in a female with chronic LBP. This case report is a single subject design. This patient is a 29-year-old female with a six-month history of low back pain following a motor vehicle accident. MRI found herniated discs at L4 and L5, clinical tests were positive for pain in the L4 and L5 dermatome and myotome the slump test was positive for neural tension, and LBP was constant at 4-6/10 over the past four months. She received axial loading exercises using a mini-trampoline and performed six sessions that were, scheduled twice a week for three weeks. Her Oswestry Disability Index (ODI) score improved from 40% at the time of her first visit to 22% at her final visit. Pain measure on the Numeric Pain Rating Scale (NPRS) after the first treatment was 7/10, and her pain after the final treatment was 0/10. These changes in the pain scores are clinically significant and exceed the minimal clinically important difference (MCID). This patient had a significant improvement in her pain using the NPRS and the ODI. This case study suggests that axial loading may be an effective treatment for some individuals with discogenic chronic low back pain.

• 한국기계가공학회지
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• 제6권1호
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• pp.50-56
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• 2007

Exhaust manifold is generally subjected to thermal cycle loadings ; at hot condition, large compressive plastic deformations are generated, and at cold condition, tensile stresses are remained in highly deformed critical zones. These phenomena originate from the fact that thermal expansions of the runners are restricted by inlet flange clamped to the cylinder head, because the former is less stiff than the latter and, the temperature of the inlet flange is lower than that of the runners. Since the failure of an exhaust manifold is mainly caused by geometric constraints between the cylinder head and the manifold, the thermal stress can be controlled by geometric factors. The generic geometric factors include the inter distance (2R), the distance from the head to the outlet (L), the tube diameter(d) and the tube thickness (t). This criteria based on elastic analysis up to onset of yield apparently indicate that the pre-stress also reduces the factor; however, high temperature relaxation may reduce this effect at later operation stage.

• 한국염색가공학회지
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• 제7권2호
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• pp.24-31
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• 1995

The properties of carbon fibers made from PAN are controlled by the heat treatment conditions. The length changes of high strength homo-PAN and co-PAN (acrylonitrile/acrylamide= 98/2wt% ) fibers under constant tensile stress during heat treatment in nitrogen gas were investigated by measuring the shrinkage behavior. In order to elucidate the relation between the length and fine structure change, the measurements of the crystalline orientation and birefringence index etc. were made for the fibers treated under linear heating up to 27$0^{\circ}C$. There are two regions in the length change with heat treatment temperature. The change in the initial period is mainaly due to the relaxation of amorphous molecular chain confined by the fiber-manufacture process. The length change in later period is considered to arise as cyclization reactions. The co-PAN fibers caused a larger shrinkage, while the onset of the shrinkage change in later period is, shifted to lower temperature. Significant morphological changes are shown to precede onset of the cyclization reactions and also during these reactions.