• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1132-1140
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• 2007

As it recently appears that Life Cycle Cost Analysis may be considered as new methodology for economic valuation of infrastructure many researches have been made to assess LCC(Life Cycle Cost) of each facility based on a reasonable methods. In general, LCC is composed of construction cost and expected maintenance repair cost. And especially, maintenance repair cost must be estimated to enhance the reliability through systematic and reasonable methods. However in Korea, because high speed railway steel bridges are recently constructed no direct statistical data are available for the account of the maintenance cost and then their maintenance characteristics are not linear yet. Therefore, the approach proposed in the paper utilizes a theoretical determination and degradation of the corrosion and fatigue of the bridges based on Rahgozar et al.(2006)'s model on fatigue notch factor considering into the corrosion to incorporate the corrosion effect into the fatigue strength reduction model. And then, the corresponding probability of failure is calculated in terms of the reliability index using S-N curve to formulate the fatigue limit state. Therefore, this paper proposes the minimum Life Cycle Cost through optimum maintenance plan analysis of high-speed railway steel bridges under construction. Finally, this paper reviews the proposed model in oder to confirm the applicability and feasibility by appling it to high speed railway steel bridges under construction

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.118-125
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• 2024

Tamai zone 4 replantation, defined as the replantation at a level proximal to the flexor digitorum superficialis' insertion and distal to where the common digital artery branches into the proper digital artery, has poor functional results because making orthosis and rehabilitation protocols that protect the bone and the flexor and extensor tendons simultaneously difficult. Two cases of Tamai zone 4 replantation are presented: one case of an index finger replantation at the proximal phalanx and a case of ring finger replantation at the proximal interphalangeal joint. The author did not repair the flexor tendon intentionally in the primary replantation and performed two-stage flexor tendon reconstruction later. The total active motions (TAMs) at the last follow-up were 215 and 180 degrees, respectively, with the latter distal interphalangeal joint being an arthrodesis. Both cases had no extension lag in the proximal interphalangeal joint. These results were much better than those in previous reports, in which the mean TAM was 133 degrees or less. The good results appeared to be mainly due to the reasonable and clear postoperative rehabilitation protocols made by the proposed procedure. This procedure may be useful for obtaining reproducible functional results even in Tamai zone 4 replantation.

• Journal of Chest Surgery
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• v.49 no.2
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• pp.92-98
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• 2016

Background: We used an Abramson technique for minimally invasive repair of pectus carinatum in patients who preferred surgery to brace therapy, had been unsuccessfully treated via brace therapy, or were unsuitable for brace therapy because of a rigid chest wall. Methods: Between July 2011 and May 2015, 16 patients with pectus carinatum underwent minimally invasive surgery. Results: The mean age of the patients was $24.35{\pm}13.20years$ (range, 14-57 years), and all patients were male. The percentage of excellent aesthetic results, as rated by the patients, was 37.5%, and the percentage of good results was 56.25%. The preoperative and postoperative Haller Index values were $2.01{\pm}0.19$ (range, 1.60-2.31), and $2.22{\pm}0.19$ (range, 1.87-2.50), respectively (p-value=0.01), and the median hospital stay was $7.09{\pm}2.91days$ (range, 5-15 days). Only one patient experienced postoperative complications. Conclusion: Minimally invasive repair is effective for the treatment of pectus carinatum, even in adult patients.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.115-122
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• 2010

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.

• Journal of the Korean Geotechnical Society
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• v.38 no.12
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• pp.79-89
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• 2022

Every summer in our country, an accident occurs, in which the retaining wall on a steep slope collapses due to torrential rain. According to the data on the results of steep slope risk assessment in 2019, over 780 retaining walls are below grade C; therefore, preparing for countermeasures is urgent. However, due to the limited budget for the repair and reinforcement of these retaining walls, it is necessary to discuss the investment prioritization. In this study, a prioritization method was proposed at the network and project levels along with the review of the revised criteria of disaster risk assessment in the steep slope retaining wall, and an application research in the network level was conducted for six retaining walls. Moreover, it is proposed that the priority index was determined by using the actual cost for repair and reinforcement in determination of the project level prioritization.

• Korean Circulation Journal
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• v.53 no.6
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• pp.406-417
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• 2023

Background and Objectives: Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement. Methods: In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity. Results: Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO₂] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO₂ was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results. Conclusions: We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.67-72
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• 2011

Purpose: There are various known methods for arthroscopic rotator cuff repair. The purpose of this retrospective study is to report on the clinical results and anatomical results of UU repair surgery, which is a new repair method. Materials and Methods: We enrolled 156 patients (88 men and 68 women) who underwent UU repair for rotator cuff tears from January 2009 to May 2010 in our hospital. Their average age was 55 years old (range: 38~75 years old) and the average follow-up period was 12 months (range: 6~23 months). For determining the results, we evaluated the VAS for pain, the daily living index (ADL) in the ASES scores, the UCLA and KSS scores, and all these tests were conducted at the first hospital visit and 6 months and 1 year after surgery and at the final follow-up. During the follow-up period, MRI was performed 3 and 6 months after surgery only in the patients who consented to MRI scans to confirm the presence of re-rupture. Results: The average scores of the VAS as a pain indicator decreased from 7.0 before surgery to 2.7 after surgery (p<0.05). The UCLA and KSS scores increased from 22.2 to 32.5 and from 83.7 to 91.5, and the changes was significant (p<0.05). For the active joint range of motion, the average forward flexion was improved from 125 to 175 degrees, the average lateral external rotation was improved from 38 to 58 degrees, and the average abduction was improved from 104 to 169 degrees. Out of a total of 156 patients, re-rupture was observed in 4 cases (3%) of 117 cases (75%) for which MRI was performed (with consent) between 3 and 6 months after surgery. Conclusion: UU repair surgery as arthroscopic repair of rotator cuff tear is a good repair method that shows excellent clinical results and a low re-rupture rate.

• Journal of Chest Surgery
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• v.26 no.8
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• pp.591-594
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• 1993

To clarify the apparent hypoplasia of the descending aorta in infants with atrioventricular septal defect[AVSD] patients, we reviewed the catheterization data and angiograms of 34 consecutive patients with AVSD less than 1 year of age who underwent repair at our institution since 1985. We compared them to 10 patients with Atrial Septal Defect[ASD] and 10 patients with Ventricular Septal Defect[VSD] who were matched for age, size and Qp/Qs. The Descending Aorta Index [DAI] of the AVSD group was not different from the VSD or ASD groups, [147.9$\pm$ 34.8 mm2/m2 versus 158.6$\pm$ 31.5 mm2/m2 and 153.2$\pm$ 43.1 mm2/m2].However, the Pulmonary Artery Index [PAI] of the AVSD group was significantly larger than the other groups [684.3$\pm$ 170.7 mm2/m2 versus 454.1$\pm$ 109.1 mm2/m2 and 534.9$\pm$ 148.4 mm2/m2][p<0.05], as was the ratio of PAI/DAI in the AVSD group [4.99$\pm$ 1.77 versus 2.89$\pm$ 0.81 and 3.6$\pm$ 0.92][p<0.05]. Despite similar Qp/Qs ratios, both the mean PA pressure and the Rp/Rs in the AVSD group was higher than the VSD and ASD groups: 43.1$\pm$ 15.6 mmHg versus 29$\pm$ 11.6 mmHg and 24$\pm$ 18.1 mmHg [p<0.05], and 0.27$\pm$ 0.22 versus 0.14$\pm$ 0.03 and 0.11$\pm$ 0.05 [p<0.05] respectively. The apparent hypoplasia of the descending aorta in infants with AVSD is an illusion created by the abnormally large pulmonary arteries, which are significantly larger than in patients with ASDs or VSDs.

• Journal of Chest Surgery
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• v.50 no.2
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• pp.71-77
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• 2017

Background: Cardiac computed tomography (CT) has emerged as an alternative to magnetic resonance imaging (MRI) for ventricular volumetry. However, the clinical use of cardiac CT requires external validation. Methods: Both cardiac CT and MRI were performed prior to pulmonary valve implantation (PVI) in 11 patients (median age, 19 years) who had undergone total correction of tetralogy of Fallot during infancy. The simplified contouring method (MRI) and semiautomatic 3-dimensional region-growing method (CT) were used to measure ventricular volumes. Results: All volumetric indices measured by CT and MRI generally correlated well with each other, except for the left ventricular end-systolic volume index (LV-ESVI), which showed the following correlations with the other indices: the right ventricular end-diastolic volume index (RV-EDVI) (r=0.88, p<0.001), the right ventricular end-systolic volume index (RV-ESVI) (r=0.84, p=0.001), the left ventricular end-diastolic volume index (LV-EDVI) (r=0.90, p=0.001), and the LV-ESVI (r=0.55, p=0.079). While the EDVIs measured by CT were significantly larger than those measured by MRI (median RV-EDVI: $197mL/m^2$ vs. $175mL/m^2$, p=0.008; median LV-EDVI: $94mL/m^2$ vs. $92mL/m^2$, p=0.026), no significant differences were found for the RV-ESVI or LV-ESVI. Conclusion: The EDVIs measured by cardiac CT were greater than those measured by MRI, whereas the ESVIs measured by CT and MRI were comparable. The volumetric characteristics of these 2 diagnostic modalities should be taken into account when indications for late PVI after tetralogy of Fallot repair are assessed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.50-57
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• 2016

The present study proposed three inspection reliability indices which compared inspection results evaluated at in-depth(routine) inspection and in-depth safety inspection; Nominal inspection reliability index, Real inspection reliability index, and DS nominal inspection reliability index. The methods to improve the inspection reliability were also proposed. Since bridge inspection process is critical to ensuring the safety of bridges and identifying repair and maintenance needs, the quality of the inspection data produced from the inspection process is very important. Consequently, the inspection reliability indices were suggested to evaluate quality of current inspection practices. Specifically, approximately 85% of inspection errors evaluated by the DS nominal inspection reliability index are within 1 rating grade(equal to or less than damage score ${\pm}0.1$). In order to improve the inspection reliability, transportation agency should implement QC(Quality Control) practices and develop professional expertises of inspectors by higher requirements for inspectors, on-off line inspection training and etc.