• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.400-407
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• 2019

In this paper, the shadow detection and reconstruction method are proposed using intrinsic image, which does not change the essential characteristics under the influence of various illuminance, and multi-scale gamma correction. The shadow detection was estimated by the pixel change information between a grayscale and an intrinsic image of the color image, and the brightness of the image were adjusted by gamma correction in the shadow restoration process. Multi-scale gamma correction is performed for each channel of a color image due to the fact that the saturation can be changed by nonlinear adjustment to individual pixel values. Multi-scale gamma values are estimated based on the information of the crossed edge between shadows and non-shadowed regions in the color image, as a result, the shadows are reconstructed by correcting different region features with multi-scale gamma values. Experimental results show that the proposed method effectively reconstructs shadows in a single natural image.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.281-296
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• 2021

The beneficial effects of hypoxic preconditioning are abolished in the diabetes. The present study was designed to investigate the protective effects and mechanisms of repeated episodes of whole body hypoxic preconditioning (WBHP) in db/db mice. The protective effects of preconditioning were explored on diabetes-induced vascular dysfunction, cognitive impairment and ischemia-reperfusion (IR)-induced increase in myocardial injury. Sixteen-week old db/db (diabetic) and C57BL/6 (non-diabetic) mice were employed. There was a significant impairment in cognitive function (Morris Water Maze test), endothelial function (acetylcholine-induced relaxation in aortic rings) and a significant increase in IR-induced heart injury (Langendorff apparatus) in db/db mice. WBHP stimulus was given by exposing mice to four alternate cycles of low (8%) and normal air O₂ for 10 min each. A single episode of WBHP failed to produce protection; however, two and three episodes of WBHP significantly produced beneficial effects on the heart, brain and blood vessels. There was a significant increase in the levels of brain-derived neurotrophic factor (BDNF) and nitric oxide (NO) in response to 3 episodes of WBHP. Moreover, pretreatment with the BDNF receptor, TrkB antagonist (ANA-12) and NO synthase inhibitor (L-NAME) attenuated the protective effects imparted by three episodes of WBHP. These pharmacological agents abolished WBHP-induced restoration of p-GSK-3β/GSK-3β ratio and Nrf2 levels in IR-subjected hearts. It is concluded that repeated episodes of WHBP attenuate cognitive impairment, vascular dysfunction and enhancement in IR-induced myocardial injury in diabetic mice be due to increase in NO and BDNF levels that may eventually activate GSK-3β and Nrf2 signaling pathway to confer protection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.8-14
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• 2019

In Korean traditional wooden architecture, joint performance varies with the material characteristics of timber, the form of joint, the precision of timber-trimming and the like. Case studies prove that the beam-to-column joint type has large influence on the degrees of deformation and spacing. This is not only true of single-story buildings, but also of large-scale multi-story buildings more apparently. Therefore, this study followed the process of examining to joint types, producing their specimens and testing their structural performance. As a consequence of structural test, the dovetail joint specimen showed the best outcomes of the maximum load and rigidity. Synthesizing the structural performances by respective forms of joints, the Doraegeoji dovetail joint specimen showed the higher performance, followed in order by the Doraegeoji mortise joint specimen and the Tongneoko dovetail joint specimen. The structural performance of a building varies with the characteristics by the shouldering forms of penetrating beams and with the joint types within the columns. This should be considered for the new construction or restoration of multi-story buildings, and be continuously researched henceforth.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.61-70
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• 2019

Objective : Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy. Methods : Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months. Results : The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected. Conclusion : The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior loadbearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.348-354
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• 2020

Purpose: Zirconia is differentiated from other ceramics because of its high resistance to corrosion and wear, excellent flexural strength (900~1400 MPa), and high hardness. Dental zirconia with proven mechanical/biological stability is suitable for the manufacture of implants. However, there are limited in vivo studies evaluating stress distribution in zirconia compared with that in titanium implants and studies analyzing finite elements. This study was conducted to evaluate the stress distribution of the supporting bone surrounding zirconia and titanium implants using the finite element analysis method. Methods: For finite element analysis, a single implant-supported restoration was designed. Using a universal analysis program, eight occlusal points were set in the direction of the occlusal long axis. The occlusal load was simulated at 700 N. Results: The zirconia implant (47.7 MPa) von Mises stress decreased by 5.3% in the upper cortical bone compared with the titanium implant (50.2 MPa) von Mises stress. Similarly, the zirconia implant (20.8 MPa) von Mises stress decreased by almost 4% in the cancellous bone compared with the titanium implant (21.7 MPa) von Mises stress. The principal stress in the cortical and cancellous bone exhibited a similar propensity to von Mises stress. Conclusion: In the supporting bone, the zirconia implant is able to reduce bone resorption caused by mechanically transferred stress. It is believed that the zirconia implant can be a potential substitute for the titanium implant by reinforcing aesthetic characteristics and improving stress distribution.

• International Area Studies Review
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• v.14 no.2
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• pp.3-23
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• 2010

The purpose of the study is to estimate value of the Eulsukdo that is attracting lots of birds. Eulsukdo became one of the most famous eco-tourism destinations worldwide and environmental restoration work is progressing with enormous budget. The input of the budget by policy judgement basically can be justified when the benefit excesses the cost in social aspect. Eulsukdo has external effect as cultural tourism resource but it is difficult to estimate the value in market. The study is to estimate the value of Eulsukdo through the single-bounded dichotomous CVM(Contingent Valuation Methods). According to analysis results, the mean WTP(Willingness to Pay) and the truncated mean WTP are estimated at 5,240 and 3,374 won in the log-normal model, and 5,888 and 3,232 won in the log-logistic model respectively. The annual total benefits value based on the truncated mean WTP is estimated at 3,870 million won in the log-normal model and 4,040 million won in log-logistic model. The result of this study will provide useful guide to policy makers and developers who fully realize the value of public goods.

• Journal of Technologic Dentistry
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• v.43 no.2
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• pp.42-47
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• 2021

Purpose: The purpose of this study was to evaluate the stability of abutment screws used with the zirconia fixture-based implant system and compare them with those used with the existing titanium fixture system via the finite element method. Methods: A single implant-supported restoration was designed for the finite element analysis. A universal analysis program was used to set 8 occlusal points along the direction to the long axis of the implant, and an occlusal load of 700 N was applied. Results: In all models (Zir and Ti-fixture model), the screw threads presented with the highest von Mises stress (VMS) values, whereas the head and end presented with the lowest VMS values. The VMS of the screw used in the zirconia-fixture model was 5.97% lower than that used in the titanium-fixture model (261.258 vs. 276.911 MPa, respectively) despite statistical significance. Furthermore, the zirconia fixture (352.912 MPa) had a higher stress value (8.42%) than the titanium fixture (332.331 MPa). In a completely tightened titanium fixture implant system, the stress was concentrated in the implant-abutment connection interface, the zirconia fixture presented with a stable stress distribution. Conclusion: Although the zirconia fixture demonstrated a high VMS value, owing to the stiffness and elasticity coefficients of the material, the stress generated in the abutment screws was similar in all models. In conclusion, the zirconia fixture-based implant system presented with a more stable stress distribution in the abutment screws than the titanium fixture-based implant system.

• Archives of Plastic Surgery
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• v.49 no.3
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• pp.304-309
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• 2022

Background Laminin 5, which is found in the basement membrane of dermal-epidermal junction (DEJ), is a major adhesive component and associated with proliferating and migrating keratinocytes. In this study, we hypothesized that the topical application of the skin care products containing the novel peptides might restore the DEJ structure by deriving deposition of laminin 5 and promoting the keratinocyte migration. Here, we evaluated the restoration of DEJ by measuring the skin thickness. Methods Single-center retrospective analysis was performed on a total of 13 patients who underwent skin care using Baume L.C.E. (France, Laboratories d' Anjou) between January and March 2021. All patients applied the skin care agent for 2 weeks only on their left hand dorsum. Before the initiation of the application and after 2 weeks, both their hands were evaluated on photography and ultrasound. And the patients were asked to rate their satisfaction with the questionnaire after 2 weeks. Results There was no obvious improvement in photographic assessment and questionnaire. The post-pre difference of skin thickness in ultrasound images was, in left hand, 0.1 ± 0.37 in distal point and 0.1 ± 0.35 in proximal point; and, in right hand, 0 ± 0.17 in distal point and 0 ± 0.15 in proximal point, respectively. The pre-post difference was statistically significant in proximal point (p = 0.035). Conclusion Topical application of novel peptide derivative comprising laminin 5 demonstrated cutaneous changes including skin thickness, as assessed by ultrasound. Further studies using other modalities including dermal density measurement, three-dimensional photography, optical coherence tomography, or skin biopsy would be helpful to determine the skin-improving effects.

• Ocean and Polar Research
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• v.44 no.3
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• pp.249-260
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• 2022

This mini review examines the habitat connectivity and effectiveness of Korean Marine Protected Areas (MPAs) in the Yellow Sea Large Marine Ecosystem (YSLME) region. We first reemphasize that the Korean region of the YSLME is a single ecosystem (ecoregion) given the biophysical distribution patterns. The MPAs within the YSLME contribute about 50% to the total MPAs in Korea, accounting for about 10% of the territorial sea waters of Korea and 20% of the waters of YSLME on the Korean side. By area, national parks account for nearly 45% of the MPAs, followed by the wetland protected areas at 25%, with other types of MPA comprising the remaining 30%. Large MPA (> 100 km²) is the dominant type of MPA, accounting for 90% of the total area. We find that MPAs in the region are connected physically and perhaps also genetically. However, the level of protection was found to be low, and a no-take zone is rarely implemented. In addition, interrupted freshwater discharge caused by river-mouth dams poses a major hindrance to the physical connectivity of the MPAs. Restoration of the river-mouth dams and strengthened regulation on MPAs, with further expansion of MPAs in line with the current development of post-2020 global biodiversity frameworks, should be priorities for better management of marine resources. The newly revised law incorporating the concept of "Marine Ecosystem Axis Management" would reinforce the processes, and their effectiveness together with overall management of MPAs in Korea should be evaluated by designing appropriate measurement tools.

• Archives of Plastic Surgery
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• v.49 no.2
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• pp.174-183
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• 2022

Management of traumatic skull base fractures and associated complications pose a unique reconstructive challenge. The goals of skull base reconstruction include structural support for the brain and orbit, separation of the central nervous system from the aerodigestive tract, volume to decrease dead space, and restoration of the three-dimensional appearance of the face and cranium with bone and soft tissues. An open bicoronal approach is the most commonly used technique for craniofacial disassembly of the bifrontal region, with evacuation of intracranial hemorrhage and dural repair performed prior to reconstruction. Depending on the defect size and underlying patient and operative factors, reconstruction may involve bony reconstruction using autografts, allografts, or prosthetics in addition to soft tissue reconstruction using vascularized local or distant tissues. The vast majority of traumatic anterior cranial fossa (ACF) injuries resulting in smaller defects of the cranial base itself can be successfully reconstructed using local pedicled pericranial or galeal flaps. Compared with historical nonvascularized ACF reconstructive options, vascularized reconstruction using pericranial and/or galeal flaps has decreased the rate of cerebrospinal fluid (CSF) leak from 25 to 6.5%. We review the existing literature on this uncommon entity and present our case series of n = 6 patients undergoing traumatic reconstruction of the ACF at an urban Level 1 trauma center from 2016 to 2018. There were no postoperative CSF leaks, mucoceles, episodes of meningitis, or deaths during the study follow-up period. In conclusion, use of pericranial, galeal, and free flaps, as indicated, can provide reliable and durable reconstruction of a wide variety of injuries.