• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.16-24
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• 1993

During 7 years, from Jan. 1986 to Dec. 1992, authors studied 208 cases of the surgically managed thyroid nodules at the Department of General Surgery, Han Kang Sacred Heart Hospital and obtained the following results. 1) Among the total 208 cases, male to female ratio was 1:11.2 in benign thyroid diseases and 1:9 in malignant thyroid diseases. The benign disease was prevalent between second and forth decade comparing with malignant disease between third and fifth decade. 2) The most common duration of illness was 3 months(26.0%). 3) Palpable neck mass was the most common chief complaint(100%). Palpitation. fatigue, and sweating were common complaints in patient with benign disease, and fatigue, palpitation, and sweating in malignant disease in decreasing order of frequency. 4) 55.8 % of lesions were in right lobe, 33.2% in left lobe, 5.8% in diffuse type, 4.8% in bilateral lobes, and 0.5% in isthmus. 5) The most common size of nodule was between 2.0cm and 3.9cm in diameter, which consisted of 55.1% of benign disease and 48.0% of malignant disease. 6) 86.5% of thyroid function test showed euthyroidism, 10.1% hyperthyroidism, and 3.4% hypothyroidism. 7) Thyroid scanning of 176 patients revealed cold nodules in 92.5% of benign diseases and in 92.9% of malignant diseases. 8) The most common benign disease was adenomatous hyperplasia(62.7%), and the most common malignant disease was papillary adenocarcinoma(80.0%). 9) Fine needle aspiration cytology was performed in 91 cases, and it showed 69.0% of sensitivity, 90.3% of specificity, and 83.5% of accuracy. 10) Frozen biopsy was performed in 109 cases. and it showed 93.9% of sensitivity, 100.0% of specificity, and 98.2% of accuracy. 11) The most commonly performed operation was unilateral lobectomy(including unilateral lobectomy with isthmectomy)(79.1%) in benign disease. and total thyroidectomy(62.0%) in malignant disease. 12) Postoperative complication showed 5 cases of wound infection (2.4%), 3 cases of transient hypoparathyroidism(1.4%), 3 cases of transient hoarseness(1.4%), 2 cases of postoperative bleeding(1.0%), 1 case of permanent hypoparathyroidism(0.5%), 1 case of permanent hoarseness(0.5%), and 1 case of postoperative pneumonia (0.5%).

• Journal of Korean Medicine for Obesity Research
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• v.16 no.1
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• pp.36-49
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• 2016

Objectives: Two historical evidence supported the concept of Gamrosu. The first one was Jeho-tang, a selected thirst quencher in Chosun Dynasty and the second one was Saeng-Maek-san, Dongeuibogam's recommendation as one of the qi-vigorating summer beverages. Gamrosu is a modified fasting therapy beverage which is manufactured from those two prescriptions and the carbohydrates (420.6 kcal/d). A retrospective observational study was conducted to evaluate the clinical outcomes. Methods: Thirty-three cases were reviewed at three local Korean Medical clinics that each site's participant has finished the modified fasting for 10 consecutive days. Clinical outcomes were reviewed at pre- and post-fasting sessions by retrieving the changes of body composition, blood pressure, blood chemistries & urine tests, and subjective symptoms & fatigue scores. Results: Demographics of the observed participants were 17 of male and 16 of female. Post-Gamrosu session, -6.89% of body weight, -8.97% of body fat mass were reduced with the nutrition indices being improved (P<0.001). -8.72% of systolic blood pressure, -39.86% of serum triglyceride, -6.75% of fast blood sugar and -8.12% of waist circumference were improved (P<0.05). The levels of high sensitivity C-reactive protein (-58.34%), CRP (-43.55%) and eosinophil (-21.30%) showed the significant diminished profiles (P<0.05). Liver/kidney functions and the standard of electrolytes were maintained within normal range in stable manners. The fatigue scale scores indicated significant lower scores. Conclusions: Taken together, obesity-related clinical outcomes after a modified fasting therapy with Gamrosu were sufficiently feasible and the observed findings should be considered for further prospective clinical studies.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.111-120
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• 2009

This paper presents a fundamental findings of the functional and structural performance of the porous asphalt concrete coated with MMA resin. To evaluate the structural performance, cantabro, wheel tracking, moisture sensitivity and indirect tensile fatigue tests are performed. The tests results show that the cantabro loss is reduced three times and fatigue resistance is significantly increased after the specimens are coated with MMA resin. However there are little changes in the rutting and moisture damage resistances before and after the coating. Air voids, permeability and BPT(British Pendulum Test) tests are conducted to study the functional performance. It is observed form the tests that the air voids and permeability are slightly decreased after the coating. However, the changes in the air voids and permeability are negligible. The skid resistance of the coated specimens is lower than reference specimens. However, the skid resistance is maintained beyond the level of the reference specimens when silica sands are chipped on top of the coated surface.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.177-183
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• 2008

The typical heat-resisting rotor steels such as 2.25CrMo, 9CrMo and 12CrW steel were experimentally studied in order to understand their materials degradation under high temperature and pressure during the long-term service, and then use the basic studies for the structural health monitoring. In order to monitor the materials degradation, it was conducted by the isothermal aging for 2.25CrMo steel, creep-fatigue for 9CrMo steel and creep for 12Cr steel with the incremental step test. The ultrasonic wave properties, electrical resistivity and coercivity were interpreted in relation to microstructural changes at each material and showed strong sensitivity to the specific microstructural evolution.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.435-443
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• 2015

Offshore structure may be considerably vulnerable to fatigue failure while initial flaw propagates under cyclic loading, so crack propagation analysis/fracture/yield assessments about initial flaw detected by NDT are necessarily required. In this paper, case studies have been conducted by flaw assessment program using engineering criticality analysis (ECA) approach. Variables such as flaw geometry, flaw size, structure geometry, dynamic stress, static stress, toughness, crack growth rate, stress concentration factor (SCF) affected by weld are considered as analysis conditions. As a result, the safety of structure was examined during fatigue loading life. Also, critical initial flaw size was calculated by sensitivity module in the developed program. The flaw assessments analysis using ECA approach can be very useful in offshore industries owing to the increasing demand on the engineering criticality analysis of potential initial flaws.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.157-173
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• 2020

In the finite element modelling of long-span cable-stayed bridges, there are a lot of uncertainties brought about by the complex structural configuration, material behaviour, boundary conditions, structural connections, etc. In order to reduce the discrepancies between the theoretical finite element model and the actual static and dynamic behaviour, updating is indispensable after establishment of the finite element model to provide a reliable baseline version for further analysis. Traditional sensitivity-based updating methods cannot support updating based on static and dynamic measurement data at the same time. The finite element model is required in every optimization iteration which limits the efficiency greatly. A convenient but accurate Kriging surrogate model for updating of the finite element model of cable-stayed bridge is proposed. First, a simple cable-stayed bridge is used to verify the method and the updating results of Kriging model are compared with those using the response surface model. Results show that Kriging model has higher accuracy than the response surface model. Then the method is utilized to update the model of a long-span cable-stayed bridge in Hong Kong. The natural frequencies are extracted using various methods from the ambient data collected by the Wind and Structural Health Monitoring System installed on the bridge. The maximum deflection records at two specific locations in the load test form the updating objective function. Finally, the fatigue lives of the structure at two cross sections are calculated with the finite element models before and after updating considering the mean stress effect. Results are compared with those calculated from the strain gauge data for verification.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.126-131
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• 2010

The purpose of this study is to assess the condition of composites used in aircraft under varying temperature environment with ultrasound guided wave technique. Investigation of crucial influential factor on the composite health monitoring related to aircraft operational environments such as the number of thermal cycles and temperature deviation between ground level and flight altitude has been of a great concern for aircraft safety issue. In this study, ultrasonic guided wave health monitoring scheme is proposed to evaluate composite specimens damaged with the thermal fatigue simulating aircraft operational condition. Guided wave dispersion curves are used to select right modes which show a promising sensitivity to each different thermal fatigue damage level. The present approach can be also implemented as one of on-lines health monitoring tools for aircraft.

• Journal of Biomedical Engineering Research
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• v.26 no.2
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• pp.123-127
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• 2005

Compression Hip Screw (CHS) is one of the most widely-used prostheses for the treatment of intertrochanteric fractures because of its strong fixation capability. Fractures at the neck and screw holes are frequently noted as some of its clinical drawbacks, which warrant more in-depth biomechanical analysis on its design variables. The purpose of this study was to evaluate changes in the strength with respect to the changes in design such as the plate thickness and the number of screw holes. Both mechanical test and FEM analysis were used to systematically investigate the sensitivities of the above-mentioned design variables. For the first part of the mechanical test, CHS (n=20) were tested until failure. The CHS specimens were classified into four groups: Group Ⅰ was the control group with the neck thickness of 6-㎜ and 5 screw holes on the side plate, Group Ⅱ 6-㎜ thick and 8 holes, Group Ⅲ 7.5-㎜ thick and 5 holes, and Group Ⅳ 7.5-㎜ thick and 8 holes. Then, the fatigue test was done for each group by imparting 50% and 75% of the failure loads for one million cycles. For the FEM analysis, FE models were made for each group. Appropriate loading and boundary conditions were applied based on the failure test results. Stresses were assessed. Mechanical test results indicated that the failure strength increased dramatically by 80% with thicker plate. However, the strength remained unchanged or decreased slightly despite the increase in number of holes. These results indicated the higher sensitivity of plate thickness to the implant strength. No fatigue failures were observed which suggested the implant could withstand at least one million cycles of fatigue load regardless of the design changes. Our FEM results also supported the above results by showing a similar trend in stress as those of mechanical test. In summary, our biomechanical results were able to show that plate thickness could be a more important variable in design for reinforcing the strength of CHS than the number of screw holes.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.259-269
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• 2018

In this study, the second order bending moment induced by sea waves is calculated using the quadratic strip theory. The theory has the fluid forcing terms including the quadratic terms of the hydrodynamic forces and the Froude-Krylov forces. They are applied to a ship as the external forces in order to estimate the second order ship responses by fluid forces. The sensitivity of the second order bending moment is investigated by implementing the quadratic terms by varying the ship side angle for two example ships. As a result, it was found that the second order bending moment changes significantly by the variation of the ship side angle. It implies that increased flare angles at the bow and the stern of ships being enlarged would amplify their vertical bending moments considerably due to the quadratic terms and may make them vulnerable to the fatigue.

• Physical Therapy Korea
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• v.4 no.2
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• pp.59-65
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• 1997

To improve the effect of balance training, visual feedback is usually used. During the training process there are some factors which decrease the effect. Neurophysiologically, the main negative factor is thought to be synaptic fatigue which decreases the sensitivity of synapses. The purpose of this study was to find a more effective balance training method. In this study, a total of 60 normal subjects-19~30 years old young males and females(M=30, F=30)-participated, and they were randomized as A, B, and C group, each group containing 20 subjects. First, all groups had a pre-test of sway balance. One minute later, A group was trained in sway balance by continuous visual feedback for 2 minutes, B group by intermittent visual feedback which had 4 sessions of 30 seconds each and a one minute rest break. C group was not trained at all. All groups had a post-test. Only B group had improved balance compared with C group by ANOVA. On the other hand, intermittent visual feedback was more effective than continuous visual feedback in sway balance training with normal subjects.