• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1402-1412
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• 2021

Chronic lateral ankle instability (CLAI) is a major complication of acute ankle sprain that can cause discomfort in both daily and sports activities and may lead to degenerative changes in the ankle joint as the long-term sequelae. The precise cause of CLAI remains debatable and is most probably multifactorial. However, identifying chronic lateral ankle ligament injury is critical in determining the primary etiology and formulating an appropriate treatment plan. This review discusses the features and effectiveness of various imaging techniques in diagnosing chronic lateral ankle ligament injury.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.77-84
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• 2020

In this paper, we developed a damage evaluation technique that can determine the damage location of a long-sized structure such as a cable-stayed bridge, and verified the performance of the developed technique through experiments. The damage assessment method aims to extract data that can evaluate the damage of the structure without the undamage data and can determine the damage location only by analyzing the response data of the structure. To complete this goal, we developed a damage assessment technique that considers variability based on the IMD theory, which is a statistical pattern recognition technique, to identify the damage location. To complete this goal, we developed a damage assessment technique that considers variability based on the IMD theory, which is a statistical pattern recognition technique, to identify the damage location. To evaluate the performance of the developed technique experimentally, cable damage experiments were conducted on model cable-stayed bridges. As a result, the damage assessment method considering variability automatically outputs the damageless data according to external force, and it is confirmed that the performance of extracting information that can determine the damage location of the cable through the analysis of the outputted damageless data and the measured damage data is shown.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.153-165
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• 2006

A damage in a structure changes its dynamic characteristics such as natural frequencies, damping ratios, and the mode shapes. In this paper the effort has been spent in obtaining the characteristics of the reduction ratio in natural frequencies and the damage detection is performed using the reduction ratios. Most of the emphasis has been on using the artificial neural network to determine the location and the extent of the damage as well as the existence of the damage. The data for learning and verifying neural network were obtained from the analytical analysis. The data have no errors. Considering the real measurements the data including errors which are difference this study between other studies also were used for neural network. The position and extent of the damage can be detected using the neural network trained by reduction ratios of natural frequencies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.165-174
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• 2010

In this paper, a two-phase structural health monitoring system using acceleration response signatures are presented to firstly alarm the change in structural condition and to secondly detect the changed location for full-scale concrete girder bridges. Firstly, Mihocheon Bridge which is a two-span continuous concrete girder bridge is selected as the target structure. The dynamic response features of Mihocheon Bridge are extracted by forced vibration test using bowling ball. Secondly, the damage alarming occurrence and the damage localization techniques are selected to design two-phase structural health monitoring system for Mihocheon Bridge. As the damage alarming techniques, auto-regressive model using time-domain signatures, correlation coefficient of frequency response function and frequency response ratio assurance criterion are selected. As the damage localization technique, modal strain energy-based damage index method is selected. Finally, the feasibility of two-phase structural health monitoring systems is evaluated from static loading tests using a dump truck.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.183-192
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• 2022

Function and performance degradation in tunnel structure can cause road's function loss, proactive maintenance is needed to prevent the initial damage from progressing to intensified damage. Inspection and diagnosis are implemented in accordance with regulations, but it does not fully reflect maintenance processes such as inspection and diagnosis, planning rehabilitation and carrying out. It was carried out for 5,540 cases inspection and diagnosis result in 1,728 tunnels was analyzed to suggest rational maintenance plan in this study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.51-57
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• 2004

An intelligent performance diagnostic computer program of a gas turbine using the NN(Neural Network) was developed. Recently on-condition performance monitoring of major gas path components using the GPA(Gas Path Analysis) method has been performed in analyzing of engine faults. However because the types and severities of engine faults are various and complex, it is not easy that all fault conditions of the engine would be monitored only by the GPA approach Therefore in order to solve this problem, application of using the NNs for learning and diagnosis would be required. Among then, a BPN (Back Propagation Neural Network) with one hidden layer, which can use an updating learning rate, was proposed for diagnostics of PT6A-62 turboprop engine in this work.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.5 no.1
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• pp.46-49
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• 2012

Diagnoses of the acromial fractures are frequently delayed because most acromial fractures are non-displaced or minimally displaced patterns and the frequency are low. We report a case that a non-displaced acromial fracture of 74 years old male hit by the falling pipes could be diagnosed by the ultrasonography. For this case who had a pain, swelling, and the limitation of active elevation of the left shoulder after direct injury, the evaluation about the rotator cuff and the biceps long head tendon was required but the early diagnosis of the non-displaced acromial fracture was done by the easier ultrasonography before the additional studies. The ultrasonography has the advantage over the computed tomography in the aspect of evaluating the injury of the tendons of the shoulder joint.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.351-359
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• 2011

In a structure, damage can occur at several scales from micro-cracking to corrosion or loose bolts. This makes the identification of damage difficult with one mode of sensing. Hence, a multi-mode actuated sensing system is proposed based on a self-sensing circuit using a piezoelectric sensor. In the self sensing-based multi-mode actuated sensing, one mode provides a wide frequency-band structural response from the self-sensed impedance measurement and the other mode provides a specific frequency-induced structural wavelet response from the self-sensed guided wave measurement. In this study, an experimental study on the pipeline system is carried out to verify the effectiveness and the robustness of the proposed structural health monitoring approach. Different types of structural damage are artificially inflicted on the pipeline system. To classify the multiple types of structural damage, a supervised learning-based statistical pattern recognition is implemented by composing a two-dimensional space using the damage indices extracted from the impedance and guided wave features. For more systematic damage classification, several control parameters to determine an optimal decision boundary for the supervised learning-based pattern recognition are optimized. Finally, further research issues will be discussed for real-world implementation of the proposed approach.

• The Korean Journal of Nuclear Medicine
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• v.22 no.2
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• pp.205-207
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• 1988

이제까지 슬관절 파열의 진단에는 관절조영술이나 관절경검사가 주로 이용되어 왔다. 저자들은 골스캔을 이응해서 슬관절 반월판 파열의 진단을 시도하였다. 슬관절 조영술이나 관절경검사로 확진된 반월판 파열 환자 7명에 대해 $^{99m}Tc-MDP$와 $^{99m}Tc-PYP$, 20mCi를 주사해서 동적, 정적영상 및 바늘구명 조준기를 이용한 영상을 얻었다. 그 소견은 1) 동적영상에서 반월판 손상부위의 혈류가 국소적으로 증가되었고, 2) 정적영상 및 바늘구멍 조준기를 이용한 영상에서 손상 부위의 경골과(tibial plateau)를 따라 특징적으로 얇은판 모양의 방사능 집적을 관찰할 수 있었다. 슬관절의 골신티그래피는 반월판 파열의 유용한 진단 방법으로 사료된다.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.198-200
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• 1999

Esophageal perforation due to the air pressure generated by forcefully evaporating gas is seldomly reported. If the diagnosis is confined to the injury of the oral cavity and the pharynx, missing the injury of the esophagus, the result may be fatal. Cases like this must be managed by early diagnosis and appropriate surgical intervention. The most important thing for early diagnosis is suspicion of esophageal injury from history and physical examination. We report two cases of esophageal pneumatic perforation caused by an explosive gas from the carbonated beverage bottle.