• Steel and Composite Structures
• /
• v.1 no.4
• /
• pp.459-480
• /
• 2001

The damage suffered by steel structures during the Northridge (1994) and Kobe (1995) earthquakes indicates that the fully restrained (FR) connections in steel frames did not behave as expected. Consequently, researchers began studying other possibilities, including making the connections more flexible, to reduce the risk of damage from seismic loading. Recent experimental and analytical investigations pointed out that the seismic response of steel frames with partially restrained (PR) connections might be superior to that of similar frames with FR connections since the energy dissipation at PR connections could be significant. This beneficial effect has not yet been fully quantified analytically. Thus, the dissipation of energy at PR connections needs to be considered in analytical evaluations, in addition to the dissipation of energy due to viscous damping and at plastic hinges (if they form). An algorithm is developed and verified by the authors to estimate the nonlinear time-domain dynamic response of steel frames with PR connections. The verified algorithm is then used to quantify the major sources of energy dissipation and their effect on the overall structural response in terms of the maximum base shear and the maximum top displacement. The results indicate that the dissipation of energy at PR connections is comparable to that dissipated by viscous damping and at plastic hinges. In general, the maximum total base shear significantly increases with an increase in the connection stiffness. On the other hand, the maximum top lateral displacement $U_{max}$ does not always increase as the connection stiffness decreases. Energy dissipation is considerably influenced by the stiffness of a connection, defined in terms of the T ratio, i.e., the ratio of the moment the connection would have to carry according to beam line theory (Disque 1964) and the fixed end moment of the girder. A connection with a T ratio of at least 0.9 is considered to be fully restrained. The energy dissipation behavior may be quite different for a frame with FR connections with a T ratio of 1.0 compared to when the T ratio is 0.9. Thus, for nonlinear seismic analysis, a T ratio of at least 0.9 should not be considered to be an FR connection. The study quantitatively confirms the general observations made in experimental results for frames with PR connections. Proper consideration of the PR connection stiffness and other dynamic properties are essential to predict dynamic behavior, no matter how difficult the analysis procedure becomes. Any simplified approach may need to be calibrated using this type of detailed analytical study.

• Korean Journal of Remote Sensing
• /
• v.39 no.2
• /
• pp.183-192
• /
• 2023

The remotely sensed data, such as satellite imagery and aerial photos, can be used to extract and detect some objects in the image through image interpretation and processing techniques. Significantly, the possibility for utilizing digital map updating and land monitoring has been increased through automatic object detection since spatial resolution of remotely sensed data has improved and technologies about deep learning have been developed. In this paper, we tried to extract plastic greenhouses into aerial orthophotos by using fully convolutional densely connected convolutional network (FC-DenseNet), one of the representative deep learning models for semantic segmentation. Then, a quantitative analysis of extraction results had performed. Using the farm map of the Ministry of Agriculture, Food and Rural Affairsin Korea, training data was generated by labeling plastic greenhouses into Damyang and Miryang areas. And then, FC-DenseNet was trained through a training dataset. To apply the deep learning model in the remotely sensed imagery, instance norm, which can maintain the spectral characteristics of bands, was used as normalization. In addition, optimal weights for each band were determined by adding attention modules in the deep learning model. In the experiments, it was found that a deep learning model can extract plastic greenhouses. These results can be applied to digital map updating of Farm-map and landcover maps.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.245-248
• /
• 2002

Research on the high performance and strength thermoplastic/continuous fiber composites was performed. New concept of impregnating die for developing continuous strand and prepreg tape of engineering plastic/glass fiber was introduced and estimated. Fully impregnated prepreg strand and tape was successfully manufactured through the new pin structure of impregnating die and control of spreading variable. Also design variables for stability of increasing processing speed were shown. And tensile strength of prepreg tape manufactured in this study was much higher than composites made by other competition company.

• Archives of Craniofacial Surgery
• /
• v.17 no.1
• /
• pp.20-24
• /
• 2016

Background: Midface concavity is a relatively common facial feature in East Asian populations. Paranasal augmentation is becoming an increasingly popular procedure for patients with mild concavity and normal occlusion. In this study, we evaluate clinical outcomes following a series of paranasal augmentation. Methods: A retrospective review was performed for patients with Class I occlusion who had undergone bilateral paranasal augmentation using custom-made silicone implants, between October 2005 and September 2013. Patient charts were reviewed for demographic information, concomitant operations, and postoperative complications. Preoperative and postoperative (1-month) photographs were used to evaluate operative outcome. Results: The review identified a total of 93 patients meeting study criteria. Overall, aesthetic outcomes were satisfactory. Five-millimeter thick silicone implant was used in 81 cases, and the mean augmentation was 4.26 mm for this thickness. Among the 93 patients, 2 patients required immediate implant removal due to discomfort. An additional 3 patients experienced implant migration without any extrusion. Nine patients complained of transient paresthesia, which had resolved by 2 weeks. There were no cases of hematoma or infection. All patients reported improvement in their lateral profile and were pleased at follow-up. Complications that arose postoperatively included 9 cases of numbness in the upper lip and 3 cases of implant migration. All cases yielded satisfactory results without persisting complications. Sensations were fully restored postoperatively after 1 to 2 weeks. Conclusion: Paranasal augmentation with custom-made silicone implants is a simple, safe, and inexpensive method that can readily improve the lateral profile of a patient with normal occlusion. When combined with other aesthetic procedures, paranasal augmentation can synergistically improve outcome and lead to greater patient satisfaction.

• Archives of Plastic Surgery
• /
• v.43 no.6
• /
• pp.590-594
• /
• 2016

Recently, the number of cases of animal bite wounds has increased significantly in concordance with an increase in the pet population around the world. The authors report two rare cases of osteomyelitis of the phalanx following cat and dog bites. On initial physical examination, signs of a severe infection were observed. Radiographs of both patients showed the presence of osteomyelitis, and in one of the patients, the diagnosis was confirmed with a bone biopsy. After use of empirical antibiotics, intravenous antibiotic therapy that matched the identified bacterium's sensitivity was initiated, and at the same time, secure dressing including debridement was performed to induce secondary healing. In addition, the patients were closely monitored with serial X-rays, and culture and blood test follow-up. One patient fully recovered without sequelae, but the other patient suffered a loss of distal interphalangeal joint motion. When dealing with bite wounds located on the hand, it is important to visit the hospital as soon as possible and receive the appropriate treatment early. Moreover, to prevent severe complications such as osteomyelitis, it is important to administer antibiotic therapy to which the cultured bacteria are sensitive, along with proper wound management and prophylactic antibiotic treatment.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.4
• /
• pp.17-23
• /
• 2003

Accurate prediction of consolidation behaviors of the soft ground improved by plastic board drains is not easy because the consolidation characteristics of the improved ground has not been fully elucidated yet. The shape of drains is one of the most important factors which affect the consolidation characteristics of the improved ground. In this paper, a series of model consolidation tests of soft clay ground improved by plastic board drain were carried out, in order to investigate the effect of both plastic board width and stress level on consolidation characteristics of the improved ground. As the results, behaviors of both settlement and excess pore pressure dissipation were elucidated. Also, the non-uniform distribution of water content in the model ground was obtained. Then, in order to investigate the effect of vertical drainage on the consolidation behavior in the model tests, the comparison between experimental consolidation behaviors and Barron's theoretical ones were carried out. As the results, it was elucidated that the consolidation behavior in the model tests was affected not only by radial drainage but also by vertical drainage.

• Archives of Plastic Surgery
• /
• v.36 no.3
• /
• pp.306-310
• /
• 2009

Purpose: Owing to improvement of microscope, microsurgery implements, and microsuture, finger replantation has shown much development. With high success rate of microsurgery in children, positive results have been reported ever from distal amputation. Here, we report the patients demographics, methods, and results of the microsurgery performed in children in our hospital for the last 8 years. Methods: From the medical records of 21 patients who had given the treatment in our hospital from January 2000 to December 2007, we analyzed patients' sex, age, operative method, and complication retrospectively. Results: The number of male patients was twice as many as female, where most patients belong to the ages of five to ten years. Operative methods performed in this study included end - to - end anastomosis of artery and vein, vein graft, and epineurial suture. As a result, 19 out of 21 cases were successfully accomplished, and four of them went through the debridement of necrotic tissue due to the partial necrosis of the lesion. A one - year follow - up observation was done after surgery and most of them were almost fully recovered like in their previous state. Conclusion: The success rate of finger replantaion in children is continuously improving despite the difficulty of vessel anastomotic procedure, rehabilitation treatment and management after surgery. We report the satisfactory results of pediatric finger replantation technically and aesthetically.

• Archives of Plastic Surgery
• /
• v.33 no.5
• /
• pp.606-611
• /
• 2006

Purpose: Animal models of a chronic wound are yet to be fully developed, and animal studies on this subject has yet to take place. The purpose of this study is to create the foundation for research on chronic wound healing based on a swine model, the most similar to that of a human. Methods: Three female 2-3 month old 'yolkshires' were used. Total of eight full thickness skin defects, $6{\times}3cm$ sized, were created on the back of each pigs. Three groups were created for comparison; Group I (n=4) was left as they were after full skin thickness excision, while the excised tissues of Group II (n=3) were turned inside out and sutured so that the epidermis would come in contact with the fascia. Group III (n=3) were excised full skin thickness in depth and silicone blocks were implanted in them. Dressing was not practised so that the wounds would be vulnerable to infection. Results: In Group III, the skin contraction rate was the least among the three groups for each three weeks of observation respectively. Also during the three weeks, bacteral colonization was at the highest among the comparison. On the third week, inflammatory cells were still active, but the generations of epidermis and collagen synthesis were detected minimally. Conclusion: The Group III was relatively the most similar model of chronic wounds. and modification of the silicone blocks, could provide us with a very effective chronic skin wound model similar to human.

• Transactions of Materials Processing
• /
• v.29 no.2
• /
• pp.69-75
• /
• 2020

The plastic strain ratio is one of the factors that affect the deep drawability of metal sheets. The plastic strain ratio of fully annealed Cu sheet is low, due to its texture being {001}<100>. In this study, in order to increase the plastic strain ratio of Cu sheets we investigated the effect of two treatments: 1^st the sheet was asymmetrically rolled and annealed, and 2^nd the sheet was symmetrically and asymmetrically rolled and subsequently annealed. The average plastic strain ratio (R_m) of the initial Cu sheet was 0.95 and |Δr| was 1.27. After the 2^nd treatment of 5.3% symmetric rolling and annealing of Cu sheet at 1000℃ for 60 min in Ar gas condition, the R_m was 2.29 times higher and the |Δr| was 1.44 times higher than that of initial Cu sheet specimen. After the 2^nd treatment of 8.2% asymmetric rolling and annealing of Cu sheet at 1000℃ for 60 min in Ar gas conditions, the R_m was 2.51 times higher and |Δr| was 0.53 times lower than that of the initial Cu sheet specimen. These results can be attributed to the change in texture of the Cu sheets due to the differences in the two methods of rolling.

• Archives of Plastic Surgery
• /
• v.49 no.6
• /
• pp.760-763
• /
• 2022

The dorsal metacarpal artery perforator flap is a flap that rises from the hand dorsum. Owing to its reliability and versatility, this flap is used as a workhorse for finger defect. However, to cover the radial-volar defect of the proximal interphalangeal joint (PIPJ) of the index finger, a longer flap is required than before. Here, we introduce the oblique extended reverse first dorsal metacarpal artery (FDMA) perforator flap to cover the radial-volar aspect defect of the index finger. A 45-year-old man got injured to the radial-volar defect of PIPJ of the left index finger caused by thermal press machine. The wound was 2 × 1 cm in size, and the joint and bone were exposed. We used FDMA perforator from anastomosis with palmar metacarpal artery at metacarpal neck. Since the defect was extended to the volar side, the flap was elevated by oblique extension to the fourth metacarpal base level. The fascia was included to the flap, and the flap was rotated counterclockwise. Finally, PIPJ was fully covered by the flap. Donor site was primarily closed. After 12 months of operation, the flap was stable without complication and limitation of range of motion. The oblique extended reverse FDMA perforator flap is a reliable method for covering the radial-volar defect of the PIPJ of the index finger. This flap, which also has an aesthetic advantage, will be a good choice for hand surgeons who want to cover the PIPJ defect of the index finger using a nonmicrosurgical option.