• 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.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.65-72
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• 2018

The purpose of this study was to assess the intra-tester and inter-tester reliability and validity of elbow flexion range of motion using a smart phone used by the general public. Thirty-one general people participated in this study. The range of motion in active elbow flexion was measured with a goniometer and smart phone over two times by two observers. The intra-taster and inter-tester reliability were evaluated using the intraclass correlation coefficient(ICC). The validity was measured by Pearson's correlation coefficient. The intra-observer reliability was good in all measured items ICC>0.900. The inter-observer reliability was high with ICC>0.806. All correlation coefficients of android app and goniometer were greater than 0.868 and showed a significant positive correlation (p<0.01). The range of motion measurement with a smart phone showed acceptable reliability. Therefore, using a smartphone to measure the range of motion of the elbow joint could provide convenience and economic benefits.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.27-34
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• 2014

In this paper, we investigate the statistical correlation of the time series for temperature measured at the heat box in the automobile drying process. We show, in terms of the sample variance, that a significant non-linear correlation exists in the time series that consist of absolute temperature changes. To investigate further the non-linear correlation, we utilize the volatility, an important concept in the financial market, and induce volatility time series from absolute temperature changes. We analyze the time series of volatilities in terms of the de-trended fluctuation analysis (DFA), a method especially suitable for testing the long-range correlation of non-stationary data, from the correlation perspective. We uncover that the volatility exhibits a long-range correlation regardless of the window size. We also analyze the cross correlation between two (inlet and outlet) volatility time series to characterize any correlation between the two, and disclose the dependence of the correlation strength on the time lag. These results can contribute as important factors to the modeling of forecasting and management of the heat box's temperature.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2430-2432
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• 1998

Generally, in the best-known Pulse-type type and Frequency Modulated Continuous Wave(FM/CW)-type RF range measurement systems, the nearest measurable distance between antenna of system and targets is limited to several tens of meters. Moreover, in case of high-speed targets it is more difficult to measure the distance precisely. In this paper we design our own RF(X-band) range(up to 15 meters) measurement system usi code correlation for high- speed targets. It 0 the correlation value between transmitting receiving PN (Pseudo -Noise) codes. So we determine the distance between antenna of s and targets using this correlation value. We fabricated it using MIC techniques and experimental results show that the proposed syste fully qualified for a short range measurement syste

• Journal of muscle and joint health
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• v.5 no.2
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• pp.253-264
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• 1998

This study has done for the purpose of investigation among the degrees of pain coping strategies, pain, and depression of patients with rheumatoid arthritis. The subjects of this study were 214 patients diagnosed with rheumatoid arthritis. The data were collected from september 4 to 16, 1995 by questionnaires. The data were analysed by the use of frequency, t-test, Pearson Correlation Coefficients, ANOVA, and Duncan test. The results Were as follows ; 1. The mean score of pain was 213.5(range : 4-390) and that of depression was 21.4 (range : 1-50). The mean score of passive pain coping strategies was 30.2(range : 11-48) and that of active pain coping strategies was 18.6(range : 7-33) 2. The passive pain coping degree showed a positive correlation with the pain degree (r=.475, p=.0001) and the active pain coping degree showed a inversive correlation with that(r= -.296, p=.0001). The passive pain coping degree showed a positive correlation with the depression degree (r=.425, p=.0001) and the active pain coping degree showed a inversive correlation with that(r=-.299, p=.0001). The pain degree showed a positive correlation with the depression degree(r=.374, p=.0001).

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.175-181
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• 2021

Objectives: The correlation between the size of a leak hole, the volume of the leakage, and the range of influence was investigated for a hydrochloric acid tank-lorry. Methods: For the case of a tank-lorry chemical accident, KORA (Korea Off-site Risk Assessment Supporting Tool) was used to predict the leak rate and the range of influence according to the size of the leak hole. The correlation was studied using R. Results: As a result of analyzing the leak rate change according to the leak hole size in a 35% hydrochloric acid tank-lorry, as the size of the leak hole increased from 1 to 100 mm, the leak rate increased from 0.008 to 83.94 kg/sec, following the power function. As a result of calculating the range of influence under conditions ranging from 1 to 100 mm in size and 10 to 60 minutes of leakage time, it was found that the range spanned from a minimum of 5.4 m to a maximum of 307.9 m. As a result of multiple regression analysis using R, the quadratic function model best explained the correlation between the size of the leak hole, the leak time, and the range of influence with an adjected coefficient of determination of 0.97 and a root mean square error of 22.33. Conclusion: If a correlation database for the size of a leak hole is accumulated for various substances and under various conditions, the amount of leakage and the range of influence can easily be calculated, facilitating field response activities.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.2
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• pp.1-7
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• 2015

PURPOSE: The aims of this study were to assess the intra-tester and inter-tester reliability and validity of hip range of motion using a smart phone in hip operative patients. METHODS: Twenty-five patients (eight total hip arthroplasty and seventeen femur neck fracture) participated in this study. The range of motions in active and passive hip flexion, abduction and external rotation were measured with a goniometer and smart phone over two times by two observers. The intra-tester and inter-tester reliability were evaluated using the intraclass correlation coefficient (ICC2,1). The validity was measured by Pearson's correlation coefficient RESULTS: The intra-observer reliability was good in all measured items (ICC>0.78). The inter-observer reliability was high with ICC (>0.90). All correlation coefficients of smart phone and goniometer was greater than 0.85 and showed a significant positive correlation (p<0.01). CONCLUSION: The range of motion measurement with a smart phone showed acceptable reliability. Therefore, it could be convenient and have economical benefits to measure the range of motion of the hip joint using a smart phone.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2559-2564
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• 2016

Purpose: To compare Ki-67 index and microvessel density MVD) in multiple myeloma and non-myeloma patients and their correlation with each other and other prognostic markers. Materials and Methods: Forty patients were enrolled in this study between 2011-2013, 30 with multiple myelomas and 10 with non-malignant disease as controls. Proliferative activity was analyzed by Ki-67 and microvessel density (MVC) was assessed by CD34 and compared between two groups. In myeloma patients, correlation between Ki-67, MVD and other prognostic factors was assessed by Pearson correlation coefficient. Results: According to Durie Salmon staging criteria, 13 patients were of stage 1, 5 of stage II and 12 of stage III. Ki-67 expression showed a positive correlation with MVD (r=0.729, p<0.001) and was significantly higher (p<0.0001) in myeloma patients (range 35-80%, mean 60.1 %) as compared to controls (range 8-25%, mean 18.1%). $MVD/mm^2$ was also significantly (p<0.0001) higher in myeloma patients (range $62-237/mm^2$, mean $178.0/mm^2$) than controls (range $5.2-50/mm^2$, mean $18.3/mm^2$). Ki-67 and MVD, both increased progressively with increasing stage of myeloma. Ki-67 showed significant positive correlation with blood urea and lactate dehydrogenase and a significant negative correlation with serum albumin. MVD showed a significant positive correlation with blood urea, lactate dehydrogenase, serum creatinine, ${\beta}2$ microglobulin and skeletal lesions. Conclusions: Ki-67 and MVD are indicators of aggressiveness and poor prognosis having significant correlation with each other and other prognostic markers of multiple myeloma. Routine assessment of these markers may help to identify high risk patients, who may benefit from with more aggressive therapy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.985-990
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• 2004

Leak noise is a good source to identify the exact location of a leak point of underground water pipelines. Water leak generates broadband noise from a leak location and can be propagated to both directions of water pipes. This sound propagation due to leak in water pipelines is not a non-dispersive wave any more because of the surrounding pipes and soil. However, the necessity of long-range detection of this leak location makes to identify low-frequency acoustic waves rather than high frequency ones. Acoustic wave propagation coupled with surrounding boundaries including cast iron pipes is theoretically analyzed and the wave velocity was confirmed with experiment. The leak locations were identified both by the acoustic emission (AE) method and the cross-correlation method. In a short-range distance, both the AE method and cross-correlation method are effective to detect leak position. However, the detection for a long-range distance required a lower frequency range accelerometers only because higher frequency waves were attenuated very quickly with the increase of propagation paths. Two algorithms for the cross-correlation function were suggested, and a long-range detection has been achieved at real underground water pipelines longer than 300m.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.798-803
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• 2004

Leak noise is a good source to identify the exact location of a leak point of underground water pipelines. Water leak generates broadband sound from a leak location and this sound propagation due to leak in water pipelines is not a non-dispersive wave any more because of the surrounding pipes and soil. However, the necessity of long-range detection of this leak location makes to identify low-frequency acoustic waves rather than high frequency ones. Acoustic wave propagation coupled with surrounding boundaries including cast iron pipes is theoretically analyzed and the wave velocity was confirmed with experiment. The leak locations were identified both by the acoustic emission (AE) method and the cross-correlation method. In a short-range distance, both the AE method and cross-correlation method are effective to detect leak position. However, the detection for a long-range distance required a lower frequency range accelerometers only because higher frequency waves were attenuated very quickly with the increase of propagation paths. Two algorithms for the cross-correlation function were suggested, and a long-range detection has been achieved at real underground water pipelines longer than 300m.