• Smart Structures and Systems
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• v.19 no.2
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• pp.225-236
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• 2017

Railroad bridges in North America are an integral but aging part of the railroad network and are typically only monitored using visual inspections. When quantitative information is required for assessment, railroads often monitor bridges using accelerometers. However without a sensor to directly measure displacements, it is difficult to interpret these results as they relate to bridge performance. Digital Image Correlation (DIC) is a non-contact sensor technology capable of directly measuring the displacement of any visible bridge component. In this research, a railroad bridge was monitored under load using DIC and accelerometers. DIC measurements are directly compared to serviceability limits and it is observed that the bridge is compliant. The accelerometer data is also used to calculate displacements which are compared to the DIC measurements to assess the accuracy of the accelerometer measurements. These measurements compared well for zero-mean lateral data, providing measurement redundancy and validation. The lateral displacements from both the accelerometers and DIC at the supports were then used to determine the source of lateral displacements within the support system.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.591-602
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• 2009

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport theory is presented for quantitative characterization of exfoliative corrosion through deconvolution procedure using a nonlinear least-square error minimization method. It produces practical information such as location and width of planar corrosion in layered structures of aircraft, which generally cannot be detected by conventional NDE techniques such as the ultrasonic method.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.9-18
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• 1998

In this paper, we present the degradation of focusing induced by velocity inhomogeneity in human tissue. For simulation, the fatty layer which is the major factor of degradation for its lower velocity, is modeled as a uniform velocity perturbation layer. And we simulate the degradation of resolution resulting from change of beam path due to refraction and the time delay due to velocity difference. We show that focusing error can be compensated for considering the velocity inhomogeneity only. The proposed compensation method can be operated in real time in the presently used digital focusing systems.

• Journal of Oriental Medical Thermology
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• v.2 no.1
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• pp.1-5
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• 2003

Dysmenorrhea is one of the common gynecologic disorders of menstruation women. Primary dysmenorrhea is menstrual pain without pelvic pathology. whereas secondary one is painful mestruation with underlying pathology. The cause of primary dysmenorrhea is increased endometrial prostaglandin. The mechanisims underlying secondary dysmenorrhea are not eluciated. There are many blood vessels under the skin and they play a very important role in the thermal control of peripheral part. The control of blood circulation is mainly controlled by autonomic nervous system and it is known that D.I.T.I. (digital infra-red thermographic imaging) is an objective method showing the body temperature. I observed the abdominal themerature of 49 patients complaning of dysmenorrhea who visited the gynecologic department of Pundang Oriental Medical Hospital during 1997. In order to rule out thermal abnormality due to obesity. the causes whose obesity index were above I. were excluded in this study. The mean temperature of lower abdomen of the dysmenorrhea group was $35.22{\pm}1.33^{\circ}C$ and control group was $36.01{\pm}0.74^{\circ}C$.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.209-216
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• 2019

Over the past decade, researchers were able to solve complex medical problems as well as acquire deeper understanding of entire issue due to the availability of machine learning techniques, particularly predictive algorithms and automatic recognition of patterns in medical imaging. In this study, a technique called transfer learning has been utilized to classify Magnetic Resonance (MR) images by a pre-trained Convolutional Neural Network (CNN). Rather than training an entire model from scratch, transfer learning approach uses the CNN model by fine-tuning them, to classify MR images into Alzheimer's disease (AD), mild cognitive impairment (MCI) and normal control (NC). The performance of this method has been evaluated over Alzheimer's Disease Neuroimaging (ADNI) dataset by changing the learning rate of the model. Moreover, in this study, in order to demonstrate the transfer learning approach we utilize different pre-trained deep learning models such as GoogLeNet, VGG-16, AlexNet and ResNet-18, and compare their efficiency to classify AD. The overall classification accuracy resulted by GoogLeNet for training and testing was 99.84% and 98.25% respectively, which was exceptionally more than other models training and testing accuracies.

• Journal of Acupuncture Research
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• v.20 no.4
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• pp.220-229
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• 2003

Objective : Cervical myelopathy is one of the most severe disease, as well as a common diesaes. However, its clinical study and report about efficiency of oriental treatment are absolutely insufficient. Therefore, we report the treatment about 1 case of Cervical myelopathy like followings. Methods : From November 27th, 2002 to January 11th, 2003, we observed patient hospitalized because of cervical myelopathy, and for its valuation, JOA score(Japanese Orthopedic Association score), Nutric grading, VAS(visual analog scale), and D.I.T.I(Digital Infrared Thermal Imaging)were used. Results : After being hospotalized for 50 days, the patients' JOA score, Nuric grading system, and VAS were improved each from 7 to 13, from grade IV to grade II, and from 8 to 2. Conclusions : We considered that oriental treatment has an useful effect on cervical myelopathy patients' treatment and recovery. But continuous studies, such as comparative studies accompanied by more treatment case.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.3
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• pp.127-136
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• 2015

Objectives This study was carried out to investigate the clinical effects of Korean medical treatment on acute peroneal nerve palsy caused by prolonged immobilization. Methods One patient with acute peroneal nerve palsy was treated with various korean medical techniques such as acupuncture, moxibustion, cupping and herbal medicine, bee-venom acupuncture for 12 weeks. Manual Muscle Test, Range of motion, Numerical Rating Scale, Ankle-hindfoot scale, Digital infrared thermographing imaging system were used to evaluate treatment effect. Results After treatment, all the scales mentioned above were improved significantly. Conclusions This result showed that Korean medical treatment is effective on acute peroneal nerve palsy caused by prolonged immoblization.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.438-444
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• 2003

A new method to measure residual stress in micron and nano scale films is described. In the theory it is based on Linear Elastic Fracture Mechanics. And in the techniques it depends on the combined capability of the focused ion beam (FIB) imaging system and of high-resolution digital image correlation (DIC) software. The method can be used for any film material (whether amorphous or crystalline) without thinning the substrate. In the method, a region of the film surface is highlighted and scanning electron images of that region taken before and after a long slot, depth a, is introduced using the FIB. The DIC software evaluates the displacement of the surface normal to the slot due to the stress relaxation by using features on the film surface. To minimize the influence of signal noise and rigid body movement, not a few, but all of the measure displacements are used for determining the real residual stress. The accuracy of the method has been assessed by performing measurements on a nano film of diamond like carbon (DLC) on glass substrate and on micro film of aluminum oxide thermally grown on Fecrally substrate. It is shown that the new method determines the residual stress ${\sigma}_R=-1.73$ GPa for DLC and ${\sigma}_R=-5.45$ GPa for the aluminum oxide, which agree quite well with ones measured independently.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1237-1244
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• 2001

An experimental study was carried out to identify the various regimes of natural convective pool boiling and to determine the boiling heat transfer curve and Critical Heat Flux(CHF) on a vertical square surface having a 70mm width and a 70mm height. The heater made of copper block with embedded cartridge heaters is submerged in a water tank at atmospheric pressure. As the heat flux increases from 100kW/㎡ to 1.2MW/㎡, the heat transfer regime migrates from the nucleate boiling to the film boiling. The boiling heat transfer data are fitted by Rohsenow type correlation. An explosive vapor generation on the heated surface, whose size and frequency are characterized by the heat flux, is visualized using a high speed digital imaging system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.877-879
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• 2013

Imaging device such as digital TV is being popular in a modern society based on communication technology. However, because of internal and external cause of system in the process of transmission, storage and acquisition, image is degraded by noise. Therefore, the importance of denoising technology is being increased, and a research for that is being actively made. In this paper, a weighted filter algorithm that considers different pixels of masks and estimated noise variance was proposed. in order to remove AWGN. And, PSNR(peak signal to noise ratio) was used to represent the excellence of proposed algorithm.