• Journal of Chest Surgery
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• v.39 no.10 s.267
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• pp.765-769
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• 2006

Background: Nuss procedure is a minimally invasive technique for correcting the pectus excavatum. But there are some limitations of correcting the complex anomaly or grown-up patients. Material and Method: we retrospectively reviewed 135 consecutive patients who underwent repair of pectus excavatum by the Nuss procedure and its modifications between November 1999 and December 2004. We analyzed the computed tomography, age on operation, operative technique, and complications. Result: We operated 135 patients of pectus excavatum during 62 months. Total number of operations about Nuss procedure is 216, including bar removal procedure of 64 cases, redo Nuss procedures of 47 cases. We modified the point of bar insertion to the hinge point, made a shoulder in the bar to prevent a displacement. And then we changed the fixation material from Vicryl to steel wire. If the patients are old, we retract the sternum during bar rotation and fixation. Until 2002, the number of redo Nuss operations were 17, complications were 23. but, after modifications, the number of redo Nuss operation were 0, complications were 2. Conclusion: This result indicates that our modifications of Nuss operation is effective, and could decrease the number of redo Nuss operation and complications.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.255-260
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• 2003

Background: Stenosis of the left pulmonary artery (LPA) after repair of tetralogy of Fallot (TOF) is troublesome. A new technique of LPA angioplasty using an autologous MPA flap was performed in patients with TOF Material and Method: From October 1998 to January 2001, 24 patients (median age; 10 months, range; 4 to 145 months) underwent total correction of TOF with LPA angioplasty using the autologous MPA flap. Five patients underwent pulmonary angioplasty without any patch over the MPA and LPA. The patches were required to enlarge only the MPA in 4 patients, and transannular RVOT widening was performed in 15. Result: There were no operative or late deaths. During follow-up (range: 6~42 months), reoperation for LPA stenosis was not required in any patients, but balloon angioplasty for branch pulmonary artery stenosis was performed in 3 patients. Echocardiography and CT angiography at the recent follow-up showed an obtuse angle between the MPA and LPA. Conclusion: Although further follow-up is needed, the angioplasty using the autologous MPA flap can be easily performed, avoiding patch-related complications, and allowing growth of the MPA flap. This angioplasty technique creates a more natural and obtuse angle between the MPA and LPA, which can minimize kinking of the LPA, especially in the patients who underwent transannular patch widening.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.4
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• pp.253-263
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• 2021

Concrete structures are damaged by aging and external environmental factors. This type of damage is to appear in the form of cracks, to proceed in the form of spalling. Such concrete damage can act as the main cause of reducing the original design bearing capacity of the structure, and negatively affect the stability of the structure. If such damage continues, it may lead to a safety accident in the future, thus proper repair and reinforcement are required. To this end, an accurate and objective condition inspection of the structure must be performed, and for this inspection, a sensor technology capable of detecting damage area is required. For this reason, we propose a deep learning-based image processing algorithm that can detect spalling. To develop this, 298 spalling images were obtained, of which 253 images were used for training, and the remaining 45 images were used for testing. In addition, an improved loss function and data augmentation technique were applied to improve the detection performance. As a result, the detection performance of concrete spalling showed a mean intersection over union of 80.19%. In conclusion, we developed an algorithm to detect concrete spalling through a deep learning-based image processing technique, with an improved loss function and data augmentation technique. This technology is expected to be utilized for accurate inspection and diagnosis of structures in the future.

• Geophysics and Geophysical Exploration
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• v.25 no.4
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• pp.189-200
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• 2022

Ground subsidence on urban roads is a social issue that can lead to human and property damages. Therefore, it is crucial to detect underground cavities in advance and repair them. Underground cavity detection is mainly performed using ground penetrating radar (GPR) surveys. This process is time-consuming, as a massive amount of GPR data needs to be interpreted, and the results vary depending on the skills and subjectivity of experts. To address these problems, researchers have studied automation and quantification techniques for GPR data interpretation, and recent studies have focused on deep learning-based interpretation techniques. In this study, we described a hyperbolic event detection process based on deep learning for GPR data interpretation. To demonstrate this process, we implemented a series of algorithms introduced in the preexisting research step by step. First, a deep learning-based YOLOv3 object detection model was applied to automatically detect hyperbolic signals. Subsequently, only hyperbolic signals were extracted using the column-connection clustering (C3) algorithm. Finally, the horizontal locations of the underground cavities were determined using regression analysis. The hyperbolic event detection using the YOLOv3 object detection technique achieved 84% precision and a recall score of 92% based on AP50. The predicted horizontal locations of the four underground cavities were approximately 0.12 ~ 0.36 m away from their actual locations. Thus, we confirmed that the existing deep learning-based interpretation technique is reliable with regard to detecting the hyperbolic patterns indicating underground cavities.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.4
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• pp.203-214
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• 2023

In this study, the physical properties and fracture characteristics according to the tensile load are evaluated on the materials of the polymeric filler and carbon fiber-based composite sleeve technique. The polymeric filler and the composite sleeve technique are applied to areas where the pipe body thickness is reduced due to corrosion in large-diameter water pipes. First, the tensile strength of the polymeric filler was 161.48~240.43 kg_f/cm², and the tensile strength of the polyurea polymeric filler was relatively higher than that of the epoxy. However, the tensile strength of the polymeric filler is relatively very low compared to ductile cast iron pipes(4,300 kg_f/cm²<) or steel pipes(4,100 kg_f/cm²). Second, the tensile strength of glass fiber, which is mainly used in composite sleeves, is 3,887.0 kg_f/cm², and that of carbon fiber is up to 5,922.5 kg_f/cm². The tensile strengths of glass and carbon fiber are higher than ductile cast iron pipe or steel pipe. Third, when reinforcing the hemispherical simulated corrosion shape of the ductile cast iron pipe and the steel pipe with a polymeric filler, there was an effect of increasing the ultimate tensile load by 1.04 to 1.06 times, but the ultimate load was 37.7 to 53.7% compared to the ductile cast iron or steel specimen without corrosion damage. It was found that the effect on the reinforcement of the corrosion damaged part was insignificant. Fourth, the composite sleeve using carbon fiber showed an ultimate load of 1.10(0.61T, 1,821.0 kg_f) and 1.02(0.60T, 2,290.7 kg_f) times higher than the ductile cast iron pipe(1,657.83 kg_f) and steel pipe(2,236.8 kg_f), respectively. When using a composite sleeve such as fiber, the corrosion damage part of large-diameter water pipes can be reinforced with same level as the original pipe, and the supply stability can be secured through accident prevention.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.580-585
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• 2008

Background: Many types of tricuspid annuloplasty are used in surgical correction of functional tricuspid regurgitation (FTR). We evaluated the mid-term and long-term outcomes in patients treated with a posterior annular plication technique (a modified Davila technique) for FTR. Material and Method: Between January 1991 and August 2006, 58 adult patients (male, 22; female, 36) with FTR of grade 2/4 or more or with tricuspid annular dilatation of more than 5.0cm in diameter, even with an FTR of less than grade 2, had received a posterior annular placation. Preoperatively, 26 patients (44.8%) had a grade 3 or more FTR. All patients had received a mitral valve replacement, and 20 (34.5%) had concomitant aortic valve replacement. Result: During the mean follow-up period of $101.4{\pm}51.6$ months, FTR disappeared or remained trivial in 28 patients (49.1%), was grade $2{\sim}3$ (${\geq}$grade 2 and $2.66{\pm}0.73\;vs.\;0.82{\pm}0.89$; p<0.0001). Patients did not require a second surgery for FTR and did not show further FTR aggravation. Conclusion: The modified Davila posterior annular plication technique for FTR has reasonable mid-term and long-term results and is a useful surgical procedure.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.513-517
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• 2010

Background: Diaphragmatic plication through a thoracoscopic approach has been an effective modality to treat diaphragmatic enventration. However, the conventional technique for thoracoscopic plication has some disadvantages. We have developed an improved and simplified technique with utilizing the head up position, $CO_2$ insufflation and figure-of-eight sutures. Material and Method: Between October 2005 and September 2009, 9 patients with diaphragmatic paralysis underwent repair using our modified technique. The mean patient age was $38.5{\pm}53.0$ years (range: 2~76 years). Result: The mean operation time was $46.7{\pm}15.9$ min (range: 30~85 min). None of the patients died due to this procedure, but there was one case of prolonged air leakage, and a case of re-expansion pulmonary edema, which required 3 days of ventilator support after the procedure. The mean hospital stay was $6.22{\pm}2.04$ days (range: 4~11 days). The mean follow-up duration was $27.2{\pm}11.6$ months (range: 2~43 months). All the patients had their symptoms relieved and there was no recurrence of eventration except for one patient who developed more than 2 cm elevation of the diaphragm compared to the immediate post-operation status. Conclusion: With our technique, thoracoscopic diaphragmatic plication was feasible via using only three 5 mm ports and without a working window and the midterm results were favorable. Therefore, we advocate thoracoscopic diaphragmatic plication as a preferred technique to the conventional open plication technique.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.168-184
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• 2022

This paper examined the construction techniques of the earthen fortifications in the Hanseong Period of Baekje Kingdom, which has been researched most frequently among the Three Kingdoms. The construction processes of the Earthen Fortifications were reviewed and dividing into 'selection of location and construction of the base', 'construction of the wall', and 'finish, extension and repair'. The results show that various techniques were mobilized for building these earthen fortifications. Techniques which were adequate for the topography were utilized for reinforcing the base, and several other techniques were used for constructing the wall. In particular, techniques for wall construction may be clearly divided into those of the fill(盛土) and panchuk(版築) techniques. The fill method has been assumed since the 2000s to have been more efficient than the panchuk technique. This method never uses the structure of the panchuk technique and is characterized by a complex soil layer line, an alternate fill, use of 'earth mound(土堤)'/'clay clod(土塊)', and junctions of oval fill units. The fill method allows us to understand active technological sharing and application among the embankment structures in the period of the Three Kingdoms. The panchuk technique is used to construct a wall using a stamped earthen structure. This technique is divided into types B1 and B2 according to the height, scale, and extension method of the structure. Type B1 precedes B2, which was introduced in the late Hanseong Period. Staring with the Pungnap Earthen Fortification in Seoul, the panchuk technique seems to have spread throughout South Korea. The techniques of the fill and panchuk techniques coexisted at the time when they appeared, but panchuk earthen fortifications gradually dominated. Both techniques have completely different methods for the soil layers, and they have opposite orders of construction. Accordingly, it is assumed that both have different technical systems. The construction techniques of the earthen fortifications began from the Hanseong Period of Baekje Kingdom and were handed down and developed until the Woongjin-Sabi Periods. In the process, it seems that there existed active interactions with other nations. Recently, since studies of the earthen fortifications have been increasing mainly in the southern areas, it is expected that comparative analysis with neighboring countries will be done intensively.

• Journal of Chest Surgery
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• v.30 no.9
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• pp.869-875
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• 1997

Perimembranous ventri ular septal defects(PMVSDS) are the most common type of ventricular septal defects(VSDs) and consist morphologically of deficiency of the membranous septum and variable portions of the adjacent muscular septum. Repair of VSD has begun via a right ventriculotomy. Even with this exposure, however, it mght lead to ventricular dysfunction. Transatrial exposure of VSDs is luiown to a versatile approach to PMVSDS and even malaligunent defects can be repaired by this method. Although transatrial exposure can be improved by taking down'the atrioventricular valve at the annulus, surgeons have been hesitant to do so because of concern for valvular competence. Therefore, this study was undertaken to clarity the effects of transamlular approach of tricuspid valve (TATV) at operation of PMVSD. During last 5 years, twenty eight cases from 96 patients of PMVSD were closed by TATV and follow up study was done from 3 months to 33 months and results were obtained as follows. 1. Age at operation was fr m 4 months to 38 years and most patients(17, 62%) were above 5 years. 2. Preoperative pulmonary-systemic flow ratio(QPIQS) was ranged from 1 to 2.8 and 22 patients(79%) were less than 2. 3. Peak systolic pulmonary artery pressure was below 30mmHg in 8, 30-50mmHg in 17, above 50mmHg in 3 patients and 25 patients(89%) were less than 50mmHg. 4. Preoperative tricuspid regurgitation(TR) is none in 12, trivial in 6, mild in 3, moderate in 5, severe in 2 patients but postoperative TR was none in 18, trivial in 6, mild in 4 patients, so TR in most patients had decreased or not. 5. Indications for operation were based on the presence of a significant shunt. However, in patients with small shunts, indications for operation were included additional factors, tricuspid valve pouch, RVOT obstruction(right ventricular outflow tract obstruction), subacute bacterial endocarditis and associated anomalies. 6. There were no hospital deaths and residual shunts in postoperative echocardiography. Therefore TATV is especially a good method in PMVSn where patients have trcuspid valve pouch. And it is a safe and effective technique that improves exposure for PMVSD repair and does not adversely affect tricuspid valvular competence.

• Journal of Chest Surgery
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• v.39 no.5 s.262
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• pp.347-353
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• 2006

Background: Despite recent advances in surgical technique and perioperative care of total anomalous pulmonary venous return (TAPVR), post-repair pulmonary vein stenosis (PVS) remains as a serious complication. We thought that the most important factors of TAPVR repair to prevent PVS were good exposure, proper alignment, and sufficient stoma size. We analyzed our experience retrospectively. Material and Method: Between Jan. 1995 and Feb. 2005, we studied 74 patients diagnosed with TAPVR suitable for biventricular repair. Supra-cardiac type (n=41, 55.4%) was the most common. Mean CPB time, ACC time, and TCA (40.5%, 30/74) time were $92.1{\pm}25.9\;min,\;39.1{\pm}10.6\;min$, and $30.2{\pm}10.7\;min$, respectively. Mean follow-up duration was $41.4{\pm}29.1$ months and follow-up was possible in all patients. Result: The median age and body weight at operation were 28.5 days ($0{\sim}478$ days) and 3.4 kg $(1.4{\sim}9\;kg)$. Early mortality was 4.1% (3/74). Causes of death were pulmonary hypertensive crisis, sepsis, and sudden death. There was PR-PVS in 2 patients (early: 1, late: 1). Both patients were cardiac type TAPVR drained to coronary sinus. Re-operations were done but only one patient survived. Cumulative survival rate in 5 year and percent freedom from PVS were $94.5{\pm}2.7%\;and\;97.2{\pm}2.0%$, respectively. Conclusion: There was no PVS in patients who underwent extra-cardiac anatomosis between LA and CPVC. Therefore it could be said that our principle might be effective in preventing PR-PVS in patients suitable two-ventricle.