• Title/Summary/Keyword: correlation measurement

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A Study on Development of a Prediction Model for the Sound Pressure Level Related to Vehicle Velocity by Measuring NCPX Measurement (NCPX 계측 방법에 따른 속도별 소음 데시벨 예측 모델 개발에 대한 연구)

  • Kim, Do Wan;An, Deok Soon;Mun, Sungho
    • International Journal of Highway Engineering
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    • v.15 no.4
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    • pp.21-29
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    • 2013
  • PURPOSES : The objective of this study is to provide for the overall SPL (Sound Pressure Level) prediction model by using the NCPX (Noble Close Proximity) measurement method in terms of regression equations. METHODS: Many methods can be used to measure the traffic noise. However, NCPX measurement can powerfully measure the friction noise originated somewhere between tire and pavement by attaching the microphone at the proximity location of tire. The overall SPL(Sound Pressure Level) calculated by NCPX method depends on the vehicle speed, and the basic equation form of the prediction model for overall SPL was used, according to the previous studies (Bloemhof, 1986; Cho and Mun, 2008a; Cho and Mun, 2008b; Cho and Mun, 2008c). RESULTS : After developing the prediction model, the prediction model was verified by the correlation analysis and RMSE (Root Mean Squared Error). Furthermore, the correlation was resulted in good agreement. CONCLUSIONS: If the polynomial overall SPL prediction model can be used, the special cautions are required in terms of considering the interpolation points between vehicle speeds as well as overall SPLs.

Study on the Measurement of Flexural Strain Using the Digital Image Correlation in the Three-Point Bending Test (이미지 상관법을 이용한 휨 변형률 측정에 관한 연구)

  • Choi, In Young;Kang, Young June;Hong, Kyung Min;Ko, Kwang Su;Lee, Hak Sung
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.5
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    • pp.498-504
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    • 2014
  • Displacements and strains are very important for material evaluation as critical factors to a machine's life cycle and safety. Typically, the strain gauge has been employed to measure displacement and strain. However, this contact-type measurement method has disadvantages that are not quantified under the test conditions of a specific object shape, surface roughness, and temperature. In this paper, the measurement of deflection and flexural strain due to the three-point bending test is presented, employing Digital Image Correlation (DIC) methods. In order to ensure measurement reliability, DIC and universal test machine methods were compared by measuring the deflections and flexural strains developed by such bending tests.

Correlation of Gender/Age and Measurement Indices of Transcranial Doppler Ultrasonography (경두개 도플러 초음파의 측정지표와 성/연령의 상관성)

  • Jin, Bok-Hee
    • Korean Journal of Clinical Laboratory Science
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    • v.42 no.3
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    • pp.155-160
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    • 2010
  • Transcranial Doppler ultrasonography (TCD) allows measurement of blood flow velocity to be made from the basal intracerebral vessels. Blood flow velocity in TCD is highly affected not only by blood vessel diameter, blood flow volume, blood viscosity, but also age and sex. Therefore, the study is focused on the correlation between TCD measurement index and sex/age. Subjects were 214 (male 147, famale 67) who had TCD for headache and stroke evaluations at Dongguk University Ilsan Hospital neurology department from December 2009 to April 2010. Sex did not show significant differences with mean flow velocity (MFV), peak systolic flow velocity (PSFV), end diastolic flow velocity (EDFV), pulsatility index (PI) and resistance index (RI) in middle cerebral artery (MCA). Although age also did not show significant differences with MFV and PSFV, EDFV has statistically decreased with age, and PI and RI has statistically increased with age. In addition, age showed significant correlation with MFV, EDFV, PI and RI, but not with PSFV. Therefore, TCD is definitely correlated with age and sex, so that those influencial factors must be considered when being tested.

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Research on Factors Affecting South Korea's OFDI Based on a Spatial Measurement Model

  • Su, Shuai;Zhang, Fan
    • Journal of Korea Trade
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    • v.26 no.1
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    • pp.99-112
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    • 2022
  • Purpose - This paper empirically investigates via a spatial lag model from the perspective of space economy to find the influencing factors of South Korea's OFDI along with 60 countries. Design/methodology - In the study of regional economic phenomena, we must first test the corresponding spatial correlation, and on this basis, complete the construction of the spatial model. For the target research object, after testing the spatial correlation, if there is spatial correlation, a spatial measurement model is needed. This paper uses the global Moran's I index for calculation. Based on the characteristics and research needs of the research object, this paper selects the spatial lag model to verify the existence of the spatial effect and factors affecting OFDI. Findings - Our results show that export scale, infrastructure, technology level, political stability, resource endowment, market size, distance and labor cost have a certain impact on Korea's OFDI, but at present the distance and market size factors are the most important influencing factors for South Korea's OFDI, The technical level and political stability have little effect on South Korea's OFDI, and are not main factors determining South Korea's OFDI. Originality/value - Through spatial measurement verification, it was found that the spatial effect has a significant impact on OFDI, along with more than 60 countries. On this basis, relevant suggestions are put forward, which have strong practical significance for South Korea's OFDI to achieve healthy and sustainable development.

A study on the development of long time exposure $SO_2$ sampler (장기 노출 $SO_2$ 간이 샘플러 개발에 관한 연구)

  • 이동인
    • Journal of Environmental Science International
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    • v.2 no.3
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    • pp.207-216
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    • 1993
  • The concentrations of $SO_2$ and $SO_3$ were measured to estimate a new developed long time exposure $SO_2$ sampler at Onsan industrial area considering the meteorological factors from June to October, 1992. The mean concentration of $SO_3$ by $PbO_2$ method was 0.924 mg $SO_3 / 10cm^2$ $PbO_2$/day and their high values were shown in the center of the industrial area, which show potential pollution due to the increase of industrial activities and micrometeorological factors in and around the sites. As a result of statistical correlation between $SO_2$ concentration by new sampling method and $SO_3$ concentration by $PbO_2$ method in July and August, 1992, correlation coefficients were high (r=0.87, 0.91) and shown more than 0.83 value in the high concentration data set, which was arbitrarily divided into 7~10${\mu}l$$SO_2$ concentration in an attempt to further investigate these relationships. Therefore, use of new developed long time exposure TEX>$SO_2$ sampler is good for TEX>$SO_2$ measurement and valuable for estimation of air quality in the urban and industrial area. Key Words : a new developed long time exposure TEX>$SO_2$ sampler, correlation coefficients, high, $SO_2$ measurement, estimation of air Quality.

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Mediating Effects of Resilience on the Relationship between Stress and Therapeutic Compliance in Patients with Systemic Lupus Erythematosus (루푸스 환자의 스트레스와 치료지시이행의 관계에 미치는 극복력의 매개효과)

  • Lee, Mi Hye;Min, Hye Sook
    • Journal of muscle and joint health
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    • v.24 no.3
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    • pp.196-204
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    • 2017
  • Purpose: This study was conducted to explore the mediating effect of resilience in the relationship between stress and therapeutic compliance in patients with systemic lupus erythematosus. Methods: The subject (N=145) was a systemic lupus erythematosus patient who visited the D Hospital in B city. Data collection was conducted from January 2016 to August 2016. Twenty-five resilience measurement tools, 20 stress measurement tools, 39 therapeutic compliance measurement tools used to measure resilience, stress and therapeutic compliance levels. The collected data were analyzed using descriptive analysis, Pearson correlation, 3-step regression analysis of Baron and Kenny, and Sobel test in SPSS/WIN 21.0. Results: There was a significant negative correlation between stress and therapeutic compliance, a significant negative correlation between stress and resilience, and significant positive correlation between resilience and therapeutic compliance. Resilience showed a direct effect on therapeutic compliance through stress as a mediating variable. Conclusion: It is necessary to develop appropriate resilience enhancement program to improve therapeutic compliance with systemic lupus erythematosus.

A Study on the Limit of Dynamic Rrange Improvement of Complementary Con-elation OTDR Caused by the Increased Measurement Cycle at Long Code Length (Complementary Correlation OTDR에서의 긴 코드 길이에 따른 측정시간 증가에 의한 Dynamic Range 증가 제한에 대한 연구)

  • 김동선;박재홍
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.11
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    • pp.19-28
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    • 2003
  • The limitation on the dynamic range improvement of the complementary correlation optical time domain reflectometer(CCOTDR) is presented. In CCOTDR, the improvement of dynamic range is function of both the averaging number of measurement cycles and the length of codes. The trade off between the averaging number and the code length restricts the improvement of the dynamic range and a very long code is not effective to improve the dynamic range. In this paper, the improvement limitation on dynamic range caused by the trade off between the averaging number and the code length is presented. For derivation of the trade off, the number of one measurement cycles employing a conventional single pulse method and employing a complementary code method are presented and compared. And the effective maximum code length is presented in addition.

Experimental Validation on Underwater Sound Speed Measurement Method Using Cross-Correlation of Time-Domain Acoustic Signals in a Reverberant Water Tank (잔향 수조에서의 시간 이력 수음 신호 간 교차상관을 이용한 수중 음속 계측 방법에 관한 실험적 검증)

  • Joo-Yeob Lee;Kookhyun Kim;Sung-Ju Park;Dae-Seung Cho
    • Journal of the Society of Naval Architects of Korea
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    • v.61 no.1
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    • pp.1-7
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    • 2024
  • Underwater sound speed is an important analysis parameter on an estimation of the underwater radiated noise (URN) emitted from vessels. This paper aims to present an underwater sound speed measurement procedure using a cross-correlation of time-domain acoustic signals and validate the procedure through an experiment in a reverberant water tank. For the purpose, time-domain acoustic signals transmitted by a Gaussian pulse excitation from an acoustic projector have been measured at 20 hydrophone positions in the reverberant water tank. Then, the sound speed in water has been calculated by a linear regression using 190 cross-correlation cases of distances and time lags between the received signals and the result has been compared with those estimated by the existing empirical formulae. From the result, it is regarded that the presented experimental procedure to measure an underwater sound speed is reliably applicable if the time resolution is sufficiently high in the measurement.

A Study for Testing Validity of Korean Pain Measurement Tool (국어통증척도의 타당도 연구)

  • 김주희
    • Journal of Korean Academy of Nursing
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    • v.16 no.1
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    • pp.81-88
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    • 1986
  • The main purpose of this study was to clarify the validity with patient's general background of Korean Pain Measurement tool. The subjects of this study were 195 patient from the 8 Med-Surgical wards in H. University Hospital in Seoul. The study was conducted over a 40 day period from Oct. 5, 1985 to Nov. 15, 1985. All patients had pain. Korean Pain Measurement tool and simple discriptive pain scale as Graphic Rating Scale were used to measure the pain, The Pearson Correlation Coefficient test was exercised to measure the correlation between the two kinds of pain tools. To clarify the Sensitivity of Korean Pain tool was used frequency with patient's response. To compare the difference in Pain levels with patient's general background, ANOVA and t-test was employed. To compare the difference in pain levels existed due to pain area of the body used mean numbers. The outcome of the study was as follows : 1. A positive correlation did exist between two pain measurement tools. (r=.2028∼.7768, p <0.002) 2. The sensitive subclass in Korean Pain Measurement tools was 7 subclass. The 7 subclass are inflammatory repeated pain, simple stimulating, traction pressure, dull pain, cavity pain, digestion related pain, suffering. related pain. 3. The existence of levels of pain in accordance with patient's general background, the department of hospital, pain area of the body and school age was supported. Age, sex, religion, marrital status, economic status, acute or chronic status was not supported. 4. The existence of higher pain levels of the body area was anus, chest, and lower pain levels of the body area was eye, ear, nose and throat. Based on the above results, it was found that sensitive subclasses of the Korean Pain Measurement tool was 7 subclass among all of 20 subclass. Thus it can be concluded that Korean Pain Mea-surement tool when partialy used and supplemented, can be an effective tool of pain measurement for the patient in Korea.

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Study on the Development of the Displacement and Strain Distribution Measurement Algorithm to the Open Hole Tension Test by Using the Digital Image Correlation (이미지 상관법을 이용한 원공 인장 시편 변위 및 변형율 측정을 위한 알고리즘 개발에 관한 연구)

  • Choi, In Young;Kang, Young June;Hong, Kyung Min;Lee, Hak Seong;Kim, Seong Jong
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.2
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    • pp.121-128
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    • 2016
  • The mechanical jointing method is very important in the machine parts and structure. They are used by the bolts and rivet because it is very convenient to replace the parts and the structure. However, the mechanical jointing methods using the bolt and rivet needed the open hole. The machine parts life cycle is reduced because this open hole created the stress concentration. Therefore, the measurement methods are needed to evaluate phenomenon of the stress concentration. This paper discusses the development of the measurement algorithm using the digital image correlation methods to measure the strain distribution of the open hole. To implement the measurement algorithm using the DIC, the LabVIEW 2010 programming tool was used. To measure the strain distribution of the open hole, the tensile specimens having an open hole are made by using the aluminum 6061-T6. To secure the reliability of measurement result using the DIC, the DIC measurement results and FEM analysis results were compared.