• Smart Structures and Systems
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• 제30권3호
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• pp.255-261
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• 2022

When no extensometer is available in a generic tensile-compression test carried out by a universal testing machine (for instance the model BIONIX from Material Testing Systems (MTS)), the test results only provide the relative displacement between the machine grips. The test does not provide any information on the local behaviour of the material. This contribution presents the potential of an application of Digital Image Correlation (DIC) toward the reconstruction of the behaviour along the specimen. In particular, the authors test a Ni-Ti shape memory alloys (SMA) specimen with emphasis on the coupling of the two measurement techniques.

• Physical Therapy Rehabilitation Science
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• 제11권3호
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• pp.311-320
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• 2022

Objective: To investigate the reliability and validity of static balance measurements using an acceleration sensor and a gyroscope sensor in smart phone inertial sensors. Design: Equivalent control group pretest-posttest. Methods: Subjects were forty five healthy adults aged twenty to fifty-years-old who had no disease that could affect the experiment. After pre-test, all participants wore a waist band with smart phone, and conducted six static balance measurements on the force plate twice for 35 seconds each. To investigate the test-retest reliability of both smart phone inertial sensors, we compared the intra-correlation coefficient (ICC 3, 1) between primary and secondary measurements with the calculated root mean scale-total data. To determine the validity of the two sensors, it was measured simultaneously with force plate, and the comparision was done by Pearson's correlation. Results: The test-retest reliability showed excellent correlation for acceleration sensor, and it also showed excellent to good correlation for gyroscope sensor(p<0.05). The concurrent validity of smartphone inertial sensors showed a mostly poor to fair correlation for tandem-stance and one-leg-stance (p<0.05) and unacceptable correlation for the other postures (p>0.05). The gyroscope sensor showed a fair correlation for most of the RMS-Total data, and the other data also showed poor to fair correlation (p<0.05). Conclusions: The result indicates that both acceleration sensor and gyroscope sensor has good reliability, and that compared to force plate, acceleration sensor has unacceptable or poor correlation, and gyroscope sensor has mostly fair correlation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.24-29
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• 1993

In this paper, the estimation of the structure of a logic circuit under test is made from the observation of the input-output correlation function by use of M-sequence, from which we can estimate whether or not any fault exist in the logic circuit. Especially, investigation was made in case of the 2_stage logic circuit. We checked theoretically the sequence of correlation function, and we have shown that the correlation function is a function of period of M-sequence only, land the appearing number of correlation function in a period is a constant value depending on the logic circuit only. And by computer simulations we have shown that the structure of the circuit under test can be estimated from the observation of sequence of correlation function.

• Journal of Advanced Marine Engineering and Technology
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• 제12권3호
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• pp.57-67
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• 1988

Although handicapped by the inability to bridge the size gap between small laboratory sample and large engineering component, the V charpy test sample method does possess certain advantages, such as each of preparation, simplicity of test method, speed, low cost in test machinery, and low cost per test. On the other hand, the COD test method does posses advantages, which reduce the size gap between the laboratory sample and actual engineering component. Consequently, the correlation between V charpy absorbed energy and the critical COD value is required for estimating critical COD value from the simple V charpy test results. In this paper, the high tensile strength steel AH36 plate specimens having a single edge cracked notch were investigated to find out the correlation between V charpy absorbed energy and critical COD value in the welded parts under such various welding methods as shielded metal arc welding, the submerged arc welding and the electro gas welding by means of V charpy impact test and static 3-point bending test. Main results obtained are as follow ; 1. The relationships between V charpy absorbed energy Wc' and critical COD value ($\delta_c$)show; $\delta_c$=0.0065 Wc'+0.1906. 2. Ductile- brittle transition behaviours can be estimated by means of fracture appearance and general yielding behaviours. 3. The V charpy absorbed energy of SMAW is higher than that of SAW, EGW and similar relationships are obtained in the COD tests.

• 한국건설순환자원학회논문집
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• 제4권2호
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• pp.203-208
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• 2016

본 논문에서는 침지내 환경을 재현한 철근부식촉진시험과 장기폭로시험을 실시하였다. 환경조건을 변수로 시험을 실시하였으며, 반전지전위법을 통한 철근부식 모니터링을 실시하였다. 부식촉진 시험결과 시험조건 별 상관계수 도출을 할 수 있었다. 촉진시험은 온도조건에 따라 인공해수의 온도가 $20^{\circ}C$인 case 1과 $65^{\circ}C$인 case 2로 구분하여 실시하였다. 고온 조건인 case 2가 1.7~1.8배 정도 상온조건인 case 1에 비해 부식을 촉진시키는 것으로 나타났으며, 해양환경시험장에서의 장기폭로시험결과와의 비교를 통해 case 1의 경우 2.45~2.94의 상관계수를 case 2의 경우 4.37~4.99의 상관계수를 나타내었다.

• 한국운동역학회지
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• 제12권2호
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• pp.245-257
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• 2002

이 연구의 목적은 간단하고 실용적이며, 타당성, 신뢰성, 객관성이 높은 체전굴 유연성 측정 도구를 개발하는데 있으며, D여자 대학교의 스포츠학 전공 여대생 44명이 자발적으로 연구의 피검자로 참여하였다. 새 측정 도구의 신뢰도와 객관도 검사는 재검법의 평균 측정값을 사용하여 이원 혼합효과 모델에 의한 급내 상관 계수를 산출하였다. 검사자별 1차와 2차의 급내 상관 계수는 L은 R = .994, Y는 R=.993, 1차와 2차 검사의 L과 Y검사자간 급내 상관 계수는 R = .985, R=.986으로 모두 상관도가 아주 높은 것으로 나타났다. 새로 개발한 체전굴 측정 도구의 타당도 검증을 위하여 Leighton-flexometer-tests의 원리를 이용한 Takei 의 flexometer를 준거 검사 도구로 사용하였으며, 1차 검사와 2차 검사에서의 새로운 체전굴 유연성 측정 도구와 준거 검사 도구 측정값의 Pearson 적률 상관계수는 각각 r = .962와 r = .960로 1, 2차 검사 모두 아주 높은 상관도를 나타냈다. 결론적으로 본 연구에서 새로 개발한 체전굴 검사는 타당도, 신뢰도, 객관도가 매우 높고 실용적인 것으로 평가될 수 있음이 밝혀졌다.

• 한국지반신소재학회논문집
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• 제10권3호
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• pp.33-41
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• 2011

본 논문에서는 국내 건설현장 29개 지점에서 국내 철도노반 다짐품질관리 방법인 반복평판재하시험과 LFWD(Light Falling Weight Deflection)에서 구한 변형률계수(Ev2)와 변형계수($E_{LFWD}$)에 대하여 응력보정을 통해 자갈재료와 사질토에 대하여 상관성을 비교하였다. 실험결과 대부분 다짐품질관리 기준을 만족하고 있으며, 입상재료의 경우 관리기준치에 약 3배이상 값을 나타내었다. 두 시험방법에 따른 상관성은 토사의 경우에는 서로 상관성이 높은 것으로 나타났지만, 강성이 상대적으로 큰 입상재료의 경우 두 시험간의 상관성이 적은 것으로 나타났다. 또한, 시험방법 별로 탄성계수를 구하여 응력상태를 보정한 후 회귀 분석한 결과 응력 보정하지 않는 조건보다 상관성이 더 높게 나타났다.

• 대한간호학회지
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• 제4권2호
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• pp.131-143
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• 1974

Antenatal care is zoomed toward3 assisting the Individual to achieve safe and wholesome state of health during pregnancy. Nature of fear is assumed to be rooted to complex interaction between past experiences, human relationship and present state of health, however. specific relationship between fear and the variables have not yet been ascertained. This study is designed to investigate the nature of fear of pregnancy, and the correlation between fear and the personal and environmental variables such as personal characteristics past experiences. and psycho-social factors. During the period from October 23 to November 5, 215 pregnant and 104 non-pregnant women of similar chronological are group residing in Seoul were interviewed according to check-list by random General anxiety test, general personality test and test for fear of pregnancy, family according to specific variables such as past experiences of Pregnancy and childbirth, structure of family, family relationship and month of pregnancy was done to the group of pregnant women. To non-pregnant group, general anxiety test was performed to compare with pregnant group. Results of the study are as follows; 1. Hypothesis 1; Degree of general anxiety will be higher e pregnant women compared to that of non-pregnant women. There is no significant difference between the general anxiety of pregnant women and that of non-pregnant women. Therefore, hypothesis I is rejected. 2. Hypothesis 2: Fear of pregnancy and general anxiety will be correlated with personality factors. Through test for fear of pregnancy and general anxiety, a meager contra-correlation between fear and only two personal factors (R and E factor) is revealed but there is no significant correlation between fear and other personal factors (A.S. and T factor). Degree of fear of pregnancy tends to b: higher in the group with low personality factors; responsibility and emotional stability expect the correlation between ascendancy, sociability, and confidence-inferiority. non-significant. Through general anxiety test, level of general anxiety tends to be higher in the group. with low personality factors; responsibility. emotional stability, and confidence except ascendency and sociability, non-significant. Hypothesis 2 is partially supported. 3. Hypothesis 3; General anxiety and fear of pregnancy will be correlated with the past experience-ol pregnancy, and child-birth experience. Though general anxiety test and test for fear of pregnancy, non-significant difference is revealed by P〉.05 level Hypothesis 3 is rejected. 4. Hypothesis 4: General anxiety and fear of pregnancy will be correlated with the month at pregnancy will be correlated with the month of pregnancy. Through tests of general anxiety and fear, significant correlation is revealed degree of fear by-P〈.05 level (CR=1.98) and level of general anxiety by P〈.005 level (CR=3. 11) is higher in the earlier stage of pregnancy. Hypothesis 4 is supported. 5. Hypothesis 5, 6, 7; General anxiety and fear of pregnancy will be correlated with socio-economic status, family structure, and family relationship. Through general anxiety test and tear of pregnancy test, non-significant is revealed by P〉.05 level. Hypothesis 3.6.7 are rejected. Conclusion and recommendation Level of general: anxiety and degree of fear of pregnancy is shown not to be correlated with variables of past experiencers of pregnancy and child-birth. and family factors except the month of - pregnancy. Personal characteristics are shown to be partially contra-correlated meagerly with genera anxiety and fear of pregnancy. This study revealed contrasted results, in regard to presence of correlation between general anxiety and fear of pregnancy to other thesis. In this context. further studies under controlled environment is recommended.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.371-376
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• 2003

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass-by-noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected.. The pass by noise test is executed according to a 2001/43/EC regulation. A]though the ISO surface has a very specific track composition, it does not reduce the variation of pass-by-noise measurements over the surface of test sites. This paper shows that the test results of pass-by-noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. 17he prediction value is range with an error within 1dB(A).

• 소음진동
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• 제6권3호
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• pp.305-315
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• 1996

Present paper aims at the correlation of modal characteristics of folding fin between test and analysis using an optimization theory. Folding fin is composed of a movable fin, a base fin, and many functional components related to the folding mechanism. Joint parts of folding fin in FEM are initially modeled as rigid elements resulting some difference between test and analysis in modal characteristics. Therefore, some equivalent springs representing joint parts are introduced to improve the FEM model. The springs were set as design variables, while the frequency difference between test and analysis was set as the object function. Bayesian procedure was ujsed for the minimization.