• Computers and Concrete
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• v.32 no.5
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• pp.475-486
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• 2023

Nondestructive evaluation (NDE) is an important task of civil engineering structure monitoring and inspection, but minor damage such as small cracks in local structure is difficult to observe. If cracks continued expansion may cause partial or even overall damage to the structure. Therefore, monitoring and detecting the structure in the early stage of crack propagation is important. The crack detection technology based on machine vision has been widely studied, but there are still some problems such as bad recognition effect for small cracks. In this paper, we proposed a deep learning method based on sweep signals to evaluate concrete surface crack with a width less than 1 mm. Two convolutional neural networks (CNNs) are used to analyze the one-dimensional (1D) frequency sweep signal and the two-dimensional (2D) time-frequency image, respectively, and the probability value of average damage (ADPV) is proposed to evaluate the minor damage of structural. Finally, we use the standard deviation of energy ratio change (ERVSD) and infrared thermography (IRT) to compare with ADPV to verify the effectiveness of the method proposed in this paper. The experiment results show that the method proposed in this paper can effectively predict whether the concrete surface is damaged and the severity of damage.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.4
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• pp.515-524
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• 1998

The purpose of this study was to evaluate the thermal properties of ceramics coated nylon fabrics by determining far infra-red emissive properties, heat storage/release and thermal insulation. Far IR emissivity and emissive power were measured for 7~ 140n at 50'C . Three types of ceramics such as cordierite with $\alpha$-alumina, a-alumina with titanium oxide and a-alumina were chosen as specimens. Cordierite with $\alpha$-alumina was chosen to treat on the fabrics due to the good emissive properties on the fabrics. Add-ons and contents of ceramics were analyzed for ceramics and/or polyurethane coated fabrics. For the physical properties, thickness and air permeability were measured. Results showed a difference in the emissive property between ceramics themselves and ceramics coated fabrics. In the ambient temperature, there was no diffenence in emissivity among the different ceramics contents. Thermography showed that when the fabric was heated with the light, surface mean temperatures of fabrics were increased as the contents of ceramics increased, and the heat storage property was confirmed. In case of same thickness and air permeability, the thermal insulation value increased as the contents of ceramics increased because of increasing heat storage and Far IR reflectivity. So there were absorption and heat storage of ceramics for Far IR from human and reflection to human between ceramics coated fabrics and human.

• The Korean Journal of Pain
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• v.27 no.4
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• pp.339-344
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• 2014

Background: The diagnostic criteria of complex regional pain syndrome (CRPS) have mainly focused on dichotomous (yes/no) categorization, which makes it difficult to compare the inter-patient's condition and to evaluate the intra-patient's subtle severity over the course of time. To overcome this limitation, many efforts have been made to create laboratory methods or scoring systems to reflect the severity of CRPS; measurement of the skin temperature asymmetry is one of the former, and the CRPS severity score (CSS) is one of the latter. However, there has been no study on the correlations among the CSS, temperature asymmetry and subjective pain score. The purpose of this study was to evaluate whether there is any correlation between the CSS, skin temperature asymmetry and subjective pain score. Methods: Patients affected with CRPS in a unilateral limb were included in this study. After making a diagnosis of CRPS according to the Budapest criteria, the CSS and skin temperature difference between the affected and unaffected limb (${\Delta}T$) was measured in each patient. Finally, we conducted a correlation analysis among the CSS, ${\Delta}T$ and visual analogue scale (VAS) score of the patients. Results: A total of 42 patients were included in this study. There was no significant correlation between the ${\Delta}T$ and VAS score (Spearman's rho = 0.066, P = 0.677). Also, the CSS and VAS score showed no significant correlation (Spearman's rho = 0.163, P = 0.303). Conclusions: The ${\Delta}T$ and CSS do not seem to reflect the degree of subjective pain in CRPS patients.

• Journal of Acupuncture Research
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• v.26 no.6
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• pp.171-178
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• 2009

Objectives : To investigate the correlation between DITI and assessment instruments of knee OA. Methods : Data were obtained from 127 subjects with OA of the knee. They were asked to answer VAS pain scale, LFI, WOMAC and KHAQ. Correlation was assessed by examing the pearson's correlation and spearman's rank correlation coefficients. Results : The thermal difference between the patella of knee was correlated with VAS, LFI and WOMAC. Age, duration, BMI and sex were not correlated with the thermal differences of each region. Conclusions : DITI value was useful for evaluating the severity of OA. And we should find out the standardization of analysis of DITI value for diagnosis of OA.

• Journal of Oriental Medical Thermology
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• v.6 no.1
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• pp.63-68
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• 2008

Purpose: We intended to researched the relations between abdominal temperature and leukorrhea. Methods: We selected the 26 leukorrhea patients and 17 control group. We measured 4 points abdominal temperature (Chung-wan(CV12), Kwan-won(CV4), Gui-rae(ST29)) by DITI. We checked the difference of temperature between CV12, CV4, ST29 of leukorrhea group and control group. And we checked the difference of temperature between CV12 and CV4 / Lt. ST29 and Rt. ST29 / CV12 and Lt. ST29 / CV12 and Rt. ST29 / CV4 and Lt. ST29 / CV4 and Rt. ST29. For statistics, we used Mann-Whitney test, SPSS 12.0 for windows. Results: The difference of temperature between CV12, CV4 and ST29 which are abdomen shows statistically insignificant result in this study. But, the difference of temperature between (${\Delta}T$) CV4 and Rt. ST29 which are abdomen shows statistically significant result. Conclusion: The leukorrhea patients show higher temperature CV12, CV4 and ST29 than control group. In lower abdomen, the temperature between leukorrhea and control group shows little difference.

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.132-140
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• 1995

Object : This study is designed to evaluate the correlation between the data of DITI(Digital Infrared Thermographic Imaging)examination and the changes of clinical symptom after the therapy of acupuncture in the patients with herniated cervical intervertebral disc. Content : The conservative therapy with acupuncture was performed during $4{\sim}5$ weeks, The acupuncture points of SI3, B62, TE3, G34, LI4, S36, GV26, G21, SII5 were used. In the pre- and post therapy, DITI examinations were performed in patients who had HIVD and were treated by acupuncture simultaneously, and then tried to correlate the results of clinical symptoms with the difference of thermographic findings at pre-acupuncture and post-acupuncture. Setting : The standard routine thermoghaphic examinations were performed with thermography(DITI) in the 15 patients with lumbar disc herniations at pre- and post acupuncture. Patient : Thermographic imaging of 15 cases were analyzed. They has disc herniations in X-ray, CT scan and MRI and they were treated by acupuncture theraphy in our hospital from March, 1994 to January, 1995. Result : 1) The causes were trauma(60%), retention of phlegm and fluid(8.7%) and cold & moisture(33.3%) 2) Levels of herniated cervical disc are C2/3(1 case). C3/4(2 cases), C5/6 & C6/7 (2 cases), C6/7(4 cases), Normal(6 cases). 3) Classifications of thermographic pattern are radiculopathy(80%), spot(13.3%), and nonspecific(6.7%) in order. 4) In evaluation Results of clinical symptom are Excellent(80%), Good(6.7%), and Poor(6.7%). Data of DITI are Excellent(80%), Good(6.7%), Fair(6.7%), and Poor(6.7%). Conclusion ; Acupuncture showed good results over 86.7% in clinical evaluation and 86.7% in DITI. Thermographic examination was valuable in the evaluation of therapeutic effect of acupuncture treatment.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.195-199
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• 1999

Background: At present, there is no reliable objective test for the diagnosis of myofascial trigger points (MFTP). We evaluated the usefulness of skin resistance point finder for the diagnosis of MFTP. Methods: 40 subjects with clinical MFTPs at the upper trapezius muscle were included in this study. Using skin resistance point finder (UNIQUE S-2010$^{(R)}$, Seik medical, Korea), we tried to find out the point of low skin resistance. At three different current level, sensitivity and specificity of this method for the diagnosis of clinically identified MFTP was evaluated. Pressure threshold for pain of low skin resistance point was measured using Pressure Threshold Meter$^{(R)}$ (Pain Diagnostics and Thermography, U.S.A.). 3 groups of point detected at different current were compared in mean pressure threshold. Results: Fixed single current of skin resistance point finder showed variable sensitivity and specificity. But, by adjusting current level, skin resistance point finder detected all of 40 clinically identified MFTPs. Although it is partially statistically significant, the mean pressure threshold of points detected at high current was high. Conclusion: Skin resistance finder can be used as objective diagnostic tool of MFTPs. There is possibility that it can be useful in evaluating treatment effect. However, more investigation is necessary.

• The Journal of Korean Medicine
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• v.33 no.1
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• pp.68-78
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• 2012

Objectives: The purpose of this study was to analyze the relationship between Yin-deficiency questionnaire score and various biofunctional signals in women. Methods: A retrospective chart review was performed on charts of 195 patients who visited Gangdong Kyung Hee Hospital between April 1st and September 30th, 2011. The subjects were categorized into two groups, a low Yin-deficiency group (n=118) and a high Yin-deficiency group (n=77). The authors analyzed the correlation between Yin-deficiency questionnaire score and biofunctional signals by Pearson's correlation coefficient test and the difference in biofunctional signals between the two groups by independent samples t-test using SPSS for windows. Results: 1. Negative correlations were observed between the temperature difference of back-humerus, standard deviation of all R-R intervals (SDNN), total power (TP), low frequency (LF), high frequency (HF) on heart rate variability parameters, and Yin-deficiency questionnaire score. A positive correlation was observed between the temperature difference of knee-humerus and Yin-deficiency questionnaire score. 2. The temperature difference of back-humerus in the high Yin-deficiency group was significantly higher than that in the low Yin-deficiency group. The temperature difference of knee-humerus, height, waist-hip ratio, SDNN, TP, LF, and HF of the high Yin-deficiency group were significantly lower than those of the low Yin-deficiency group. Conclusions: The results of this study suggest that the comprehensive diagnosis of Yin-deficiency and biofunctional signals is useful.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.3
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• pp.248-253
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• 2014

Camera calibration is an indispensable process for improving measurement accuracy in industry fields such as machine vision. However, existing calibration cannot be applied to the calibration of mid-wave and long-wave infrared cameras. Recently, with the growing use of infrared thermal cameras that can measure defects from thermal properties, development of an applicable calibration target has become necessary. Thus, based on heat conduction analysis using finite element analysis, we developed a calibration target that can be used with both existing visible cameras and infrared thermal cameras, by implementing optimal design conditions, with consideration of factors such as thermal conductivity and emissivity, colors and materials. We performed comparative experiments on calibration target images from infrared thermal cameras and visible cameras. The results demonstrated the effectiveness of the proposed calibration target.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.91-98
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• 2017

Recently, composite materials have been mainly used in the main wings, ailerons, and fuselages of aircraft and rotor blades of helicopters. Composite materials used in rapid moving structures are subject to impact by hail, lightning, and bird strike. Such an impact can destroy fiber tissues in the composite materials as well as deform the composite materials, resulting in various problems such as weakened rigidity of the composite structure and penetration of water into tiny cracks. In this study, experiments were conducted using a 2 kW halogen lamp which is most frequently used as a light source, a 2 kW near-infrared lamp, which is used for heating to a high temperature, and a 6 kW xenon flash lamp which emits a large amount of energy for a moment. CFRP composite sandwich panels using Nomex honeycomb core were used as the specimens. Experiments were carried out under impact damages of 1, 4 and 8 J. It was found that the detection of defects was fast when the xenon flash lamp was used. The detection of damaged regions was excellent when the halogen lamp was used. Furthermore, the near-infrared lamp is an effective technology for showing the surface of a test object.