• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.322-331
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• 2017

District heating was first introduced in Korea in 1985. As the service life of the underground thermal piping network has increased for more than 30 years, the maintenance of the underground thermal pipe has become an important issue. A variety of complex technologies are required for periodic inspection and operation management for the maintenance of the aged thermal piping network. Especially, it is required to develop a model that can be used for decision making in order to derive optimal maintenance and replacement point from the economic viewpoint in the field. In this study, the analysis was carried out based on the repair history and accident data at the operation of the thermal pipe network of five districts in the Korea District Heating Corporation. A failure probability model was developed by introducing statistical techniques of qualitative analysis and binomial logistic regression analysis. As a result of qualitative analysis of maintenance history and accident data, the most important cause of pipeline damage was construction erosion, corrosion of pipe and bad material accounted for about 82%. In the statistical model analysis, by setting the separation point of the classification to 0.25, the accuracy of the thermal pipe breakage and non-breakage classification improved to 73.5%. In order to establish the failure probability model, the fitness of the model was verified through the Hosmer and Lemeshow test, the independent test of the independent variables, and the Chi-Square test of the model. According to the results of analysis of the risk of thermal pipe network damage, the highest probability of failure was analyzed as the thermal pipeline constructed by the F construction company in the reducer pipe of less than 250mm, which is more than 10 years on the Seoul area motorway in winter. The results of this study can be used to prioritize maintenance, preventive inspection, and replacement of thermal piping systems. In addition, it will be possible to reduce the frequency of thermal pipeline damage and to use it more aggressively to manage thermal piping network by establishing and coping with accident prevention plan in advance such as inspection and maintenance.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.22-27
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• 2015

We evaluated outcomes of dogs surgically treated for grade 2 or 3 medial patellar luxation (MPL) with and without trochleoplasty. A retrospective study of 63 dogs with grade 2 or 3 MPL surgically treated with or without trochleoplasty was performed. Results of radiographic evaluation were expressed numerically as degenerative joint disease score and were compared between the groups with and without trochleoplasty. The study included 7 (7/68, 10.3%) cases of reluxation and 1 case of tibial tuberosity transposition implant failure. Reluxation and complications requiring additional surgery were confirmed in 3 cases (3/47, 6.4%) in trochleoplasty group and in 1 case (1/21, 4.8%) in nontrochleoplasty group. The nontrochleoplasty group showed a shorter recovery time than the trochleoplasty group (P < 0.05). There was a significant difference in degenerative joint disease scores over time between the groups, with nontrochleoplasty group having lower scores (P < 0.05). This study suggests that surgical treatment without trochleoplasty results in favorable outcomes compared to treatment with trochleoplasty. It is not mandatory to exclude trochleoplasty when performing surgery for grade 2 or 3 MPL, but we propose that surgical treatment without trochleoplasty is one option when choosing a combination of surgical techniques.

• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.366-370
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• 2005

Background: In general, cardiac surgery has been performed via median sternotomy. During the past decade, improvements in endoscopic equipment and operative techniques have resulted in development of minimally invasive cardiac operation using small incisions. With the advent of a voice controlled camera-holding robotic arm (AESOP 3000, Automated Endoscope System for Optimal Positioning), cardiac surgery entered the robotic age. Material and Method: Between April 2004 and December 2004, a total of seventy eight patients underwent robotic cardiac surgery, of whom sixty four patients underwent robot-assisted minimally invasive cardiac surgery via 5cm right lateral minithoracotomy using voice controlled robotic arm, femoral vessels cannulation, percutaneous internal jugular cannulation, transthoracic aortic cross clamp. Other fourteen patients underwent MIDCAB via internal mammary artery harvesting using AESOP. Result: Robotic cardiac surgery were mitral valve repair in 37 cases, mitral valve replacement in 10 cases, aortic valve replacement in 1 case, MIDCAB in 14 cases, ASD operation in 9 cases, and isolated Maze procedure in 1 case. In mitral operation, mean CPB time was $165.3\pm43.1$ minutes and mean ACC time was $110.4\pm48.2$ minutes. Median length of hospital stay was 6 days (range 3 to 30) in mitral operation, 4 days (range 2 to 7) in MIDCAB, and 4 days (range 2 to 6) in ASD operation. For complications, 3 patients were required by reoperation for bleeding. There was no hospital mortality. Conclusion: Our experience of robot cardiac surgery suggests that many cardiovascular surgeons will be able to perform minimally invasive cardiac operations through small incisions with robot-assisted video-direction. Well-designed studies and close long-term follow-up will be required to analyze the benefits of robot-assisted operation.

• Journal of Chest Surgery
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• v.35 no.2
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• pp.102-112
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• 2002

This study was undertaken to analyze the outcome of composite valve graftreplacement(CVGR) for the treatment of aneurysms of the ascending aorta involving the aortic root. Material and Method: Between April 1995 and June 2001, 56 patients had replacement of the ascending aorta and aortic root with a composite graft valve and were reviewed retrospectively. Aortic regurgitation was present in 50 patients(89%), Marfan's syndrome in 18 patients(32%), and bicuspid aortic valve in 7(12.5%). The indications for operation were annuloaortic ectasia(AAE) in 30 patients(53.6%), aortic dissection in 13(23.2%), aneurysms of the ascending aorta involving aortic root in 11(19.6%), and aortitis in 2(3.6%). Cardiogenic shock due to the aortic rupture was present in 2 patients. Nine patients(16%) had previous operations on the ascending aorta or open heart surgery. The operative techniques used for CVGR were the aortic button technique in 51 patients(91%), the modified Cabrol technique in 4, and the classic Bentall technique in 1. The concomitant procedures were aortic arch replacement in 24 patients(43%), coronary artery bypass graft in 8(14.3%), mitral valve repair in 2, redo mitral valve replacement in 1, and the others in 7 The mean time of circulatory arrest, total bypass, and aortic crossclamp were 21$\pm$14 minutes, 186$\pm$68 minutes, and 132$\pm$42 minutes, respectively. Result: Early mortality was 1.8%(1/56). The postoperative complications were left ventricular dysfunction in 16 patients(28.6%), reoperation for bleeding in 7(12.5%), pericardial effusion in 2, and the others in 7. Fifty-three patients out of 55 hospital survivors were followed up for a mean of 23.2 $\pm$ 18.7 months(1-75 months). There were two late deaths(3.8%) including one death due to the traumatic cerebral hemorrhage, and CVGR-related late mortality was 1.9%. The 1- and 6-year actuarial survival was 98.1$\pm$1.9% and 93.2$\pm$5.1%, respectively. Two patients required reoperation for complication of CYGR(3.8%) and two other patients required subsequent operations for dissection of the remaining thoracoabdominal aorta. The 1- and 6-year actuarial freedom from reoperation was 97.8$\pm$2.0% and 65.3$\pm$26.7%, respectively.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.812-819
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• 2003

Background: Left ventricular dysfunction is one of the important prognostic factors of early mortality and long-term survival after valve operation. We studied the intermediate term results of mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction. Material and Method: Forty four patients who underwent mitral valve reconstruction with a left ventricular ejection fraction (EF) of <45% or less (20∼45%) from April 1995 through July 2001 were reviewed retrospectively. Ages ranged from 10 to 67 years (46∼14 years) and 32 patients were in NYHA class III-IV. The mitral valve diseases were regurgitation (MR) in 28 patients, stenosis(MS) in 10, and mixed lesion in 5. The etiologies of mitral valve disease were rheumatic in 20 patients, degenerative in 14, ischemic in 5, annular dilatation in 2, congenital in 2, and endocarditis in 1. Operatively, all patients had annuloplasty and/or various valvuloplasty techniques, and a total of 52 procedures were concomitantly performed. Total cardiopulmonary bypass and aortic crossclamp time were 160$\pm$57 minutes and 112$\pm$45 minutes respectively. Result: Two operative deaths occurred as a result of left ventricular failure (4.5%). After the mean follow-up of 39 months (range, 10∼83 months), there was no late death. Transthoracic echocardiography revealed no or grade I of MR in 29 patients (72.5%) and no or mild MS in 35 patients (87.5%). The actuarial survival at 5 years was 100%. Four patients required mitral valve replacement due to progressive mitral valvular disease. The actuarial freedom from valve-related reoperation at 5 years was 84$\pm$9%. Conclusion: This study suggests that mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction offers good early and intermediate survival and acceptable freedom from valve-related reoperation, and it is the strategy for effective management for these patients.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.243-263
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• 2022

The royal court of Joseon had a tradition of mounting the Irworobongdo, a painting of the sun, the moon and the five sacred peaks, symbols of the king's immortal presence and authority, on a folding screen and placing it in special spaces within the palace that were reserved for the king. While the Irworobongdo is generally accepted as the important ceremonial object of the royal palaces of Joseon, there have been few studies on the various folding screens used in the royal palaces, largely because the official records about such screens do not match the remaining original relics. In this study, the main discussion is focused on the diversity of the shapes and mounting materials of the Irworobongdoused for various ceremonies held in the royal palaces of Joseon based on the Uigwe, the official records of the royal protocols of the Joseon dynasty. The discussion also extends to the theme rarely studied so far, namely the original form of the Irworobongdo and its evolution in the following period. The ceremonial "five peak" folding screens (Obongbyeong) used at a number of important palace buildings, including the crown hall (Jeongjeon), royal funerary hall (Binjeon), spirit hall (Honjeon) and portrait shrine (Jinjeon), differed in shape and size from the folding screens used in royal celebratory events such as banquets, although the paintings themselves and the style of mounting them were essentially the same. The paintings were mounted on screens bordered with green silk and ornamented with floral gilt designs. The folding screens used in royal ceremonies were produced according to strict guidelines that required the ceremonies and mounting materials to be graded on the basis of the status of each screen. It was not until the 1960s that these ceremonial folding screens of the Joseon dynasty, which had been neglected during the period of Japanese colonial rule of Korea, began to undergo conservation treatment provided as part of a heritage preservation program. Unfortunately, many of the screens repaired in this period lost some of their original features - largely due to the use of non-traditional mounting techniques. Considering, however, that significant achievements have since been made in the heritage preservation field based on the use of historical evidence, it is now necessary to systematically use the repair history of the information about the remaining royal ceremonial folding screens to ensure that they are preserved and managed more effectively in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.2
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• pp.110-126
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• 2024

This study conducted a classification of small-scale biological habitats created in Seoul to analyze and synthesize location characteristics, habitat structure, biological habitat functions, and threat factors of representative sites, as well as derive creation and management problems according to the ecological characteristics. The aim was to suggest improvement measures and management items. Data collected through a field survey was used to categorize 39 locations, and 8 representative sites were selected by dividing them into location, water system, and size as classification criteria for typification. Due to the characteristics of each type, the site was created in an area where amphibian movement was disadvantageous due to low or disconnected connectivity with the hinterland forest, and the water supply was unstable in securing a constant flow and maintaining a constant water depth. The habitat structure has a small area, an artificial habitat structure that is unfavorable for amphibians, having the possibility of sediment inflow, and damage to the revetment area. The biological habitat function is a lack of wetland plants and the distribution of naturalized grasses, and threats include the establishment of hiking trails and decks in the surrounding area. Artificial disturbances occur adjacent to facilities. When creating habitats according to the characteristics of each type, it was necessary to review the possibility of an artificial water supply and introduce a water system with a continuous flow in order to connect the hinterland forest for amphibian movement and locate it in a place where water supply is possible. The habitat structure should be as large as possible, or several small-scale habitats should be connected to create a natural waterfront structure. In addition, additional wetland plants should be introduced to provide shelter for amphibians, and facilities such as walking paths should be installed in areas other than migration routes to prevent artificial disturbances. After construction, the management plan is to maintain various water depths for amphibians to inhabit and spawn, stabilize slopes due to sediment inflow, repair damage to revetments, and remove organic matter deposits to secure natural grasses and open water. Artificial management should be minimized. This study proposed improvement measures to improve the function of biological habitats through the analysis of problems with previously applied techniques, and based on this, in the future, small-scale biological habitat spaces suitable for the urban environment can be created for local governments that want to create small-scale biological habitat spaces, including Seoul City. It is significant in that it can provide management plans.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.845-855
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• 2004

Background: No general consensus has been available regarding the necessity of postoperative radiation therapy (PORT) and its optimal techniques in the patients with chest wall invasion (pT3cw) and node negative (N0) non-small cell lung cancer (NSCLC). We did retrospective analyses on the pT3cwN0 NSCLC patients who received PORT because of presumed inadequate resection margin on surgical findings. And we compared them with the pT3cwN0 NSCLC patients who did not received PORT during the same period. Material and Method: From Aug. of 1994 till June of 2002, 22 pT3cwN0 NSCLC patients received PORT-PORT (＋) group- and 16 pT3cwN0 NSCLC patients had no PORT-PORT (-) group. The radiation target volume for PORT (＋) group was confined to the tumor bed plus the immediate adjacent tissue only, and no regional lymphatics were included. The prognostic factors for all patients were analyzed and survival rates, failure patterns were compared with two groups. Result: Age, tumor size, depth of chest wall invasion, postoperative mobidities were greater in PORT (-) group than PORT (＋) group. In PORT (-) group, four patients who were consulted for PORT did not receive the PORT because of self refusal (3 patients) and delay in the wound repair (1 patient). For all patients, overall survival (OS), disease-free survival (DFS), loco-regional recurrence-free survival (LRFS), and distant metastases-free survival (DMFS) rates at 5 years were 35.3%, 30.3%, 80.9%, 36.3%. In univariate and multivariate analysis, only PORT significantly affect the survival. The 5 year as rates were 43.3% in the PORT (＋) group and 25.0% in PORT (-) group (p=0.03). DFS, LRFS, DMFS rates were 36.9%, 84.9%, 43.1 % in PORT (＋) group and 18.8%, 79.4%, 21.9% in PORT(-) group respectively. Three patients in PORT (-) group died of intercurrent disease without the evidence of recurrence. Few suffered from acute and late radiation side effects, all of which were RTOG grade 2 or lower. Conclusion: The strategy of adding PORT to surgery to improve the probability not only of local control but also of survival could be justified, considering that local control was the most important component in the successful treatment of pT3cw NSCLC patients, especially when the resection margin was not adequate. Authors were successful in the marked reduction of the incidence as well as the severity of the acute and late side effects of PORT, without taking too high risk of the regional failures by eliminating the regional lymphatics from the radiation target volume.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.200-211
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• 2022

The celadon stools with an openwork ring design which consist of four items as one collection were excavated from Gaeseong, Gyeonggi-do Province. The celadon stools were designated and managed as treasures due to their high arthistorical value in the form of demonstrating the excellence of celadon manufacturing techniques and the fanciful lifestyles during the Goryeo Dynasty. However, one of the items, which appeared to have been repaired and restored in the past, suffered a decline in aesthetic value due to the aging of the treatment materials and the lack of skill on the part of the conservator, raising the need for re-treatment as a result of structural instability. An examination of the conservation condition prior to conservation treatment found structural vulnerabilities because physical damage had been artificially inflicted throughout the area that was rendered defective at the time of manufacturing. The bonded surfaces for the cracked areas and detached fragments did not fit, and these areas and fragments had deteriorated because the adhesive trickled down onto the celadon surface or secondary contaminants, such as dust, were on the adhesive surface. The study identified the position, scope, and conditions of the bonded areas at the cracks UV rays and microscopy in order to investigate the condition of repair and restoration. By conducting Fourier-transform infrared spectroscopy(FT-IR) and portable x-ray fluorescence spectroscopy on the materials used for the former conservation treatment, the study confirmed the use of cellulose resins and epoxy resins as adhesives. Furthermore, the analysis revealed the addition of gypsum(CaSO₄·2H₂O) and bone meal(Ca₁₀ (PO₄)₆(OH)₂) to the adhesive to increase the bonding strength of some of the bonded areas that sustained force. Based on the results of the investigation, the conservation treatment for the artifact would focus on completely dismantling the existing bonded areas and then consolidating vulnerable areas through bonding and restoration. After removing and dismantling the prior adhesive used, the celadon stool was separated into 6 large fragments including the top and bottom, the curved legs, and some of the ring design. After dismantling, the remaining adhesive and contaminants were chemically and physically removed, and a steam cleaner was used to clean the fractured surfaces to increase the bonding efficacy of the re-bonding. The bonding of the artifact involved applying the adhesive differently depending on the bonding area and size. The cyanoacrylate resin Loctite 401 was used on the bonding area that held the positions of the fragments, while the acrylic resin Paraloid B-72 20%(in xylene) was treated on cross sections for reversibility in the areas that provided structural stability before bonding the fragments using the epoxy resin Epo-tek 301-2. For areas that would sustain force, as in the top and bottom, kaolin was added to Epo-tek 301-2 in order to reinforce the bonding strength. For the missing parts of the ring design where a continuous pattern could be assumed, a frame was made using SN-sheets, and the ring design was then modeled and restored by connecting the damaged cross section with Wood epos. Other restoration areas that occurred during bonding were treated by being filled with Wood epos for aesthetic and structural stabilization. Restored and filled areas were color-matched to avoid the feeling of disharmony from differences of texture in case of exhibitions in the future. The investigation and treatment process involving a variety of scientific technology was systematically documented so as to be utilized as basic data for the conservation and maintenance.