• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.1-8
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• 2019

Pintail (Anas acuta) is the major wintering bird in South Korea and known as a major mediator of the highly pathogenic avian influenza (HPAI). Pintail migrates long distances between Russian Siberia and Korea. This species prefers a rice paddy area as their winter habitat. The purpose of this study is to provide the data necessary for the conservation and management of bird habitats in Korea by understanding the wintering home-range and habitat of pintail in Korea. We captured six pintails using a cannon-net in the winter of 2015 and attached the GPS-mobile phone based telemetry (WT-300) on them to study the wintering home-range and wintering habitat. We analyzed the tracking location data using ArcGIS 9.0 Animal Movement Extension and calculated Kernel Density Estimation (KDE) and Minimum Convex Polygon (MCP). The average home-range in the wintering ground analyzed by MCP was $677.3km^2$ (SD=130.2, n=6) while the maximum and minimum were $847.7km^2$ and $467.5km^2$, respectively. Extents of home-range analyzed by KDE were $194.7km^2$ (KDE 90%), $77.4km^2$ (KDE 70%), and $35.3km^2$ (KDE 50%). The pintails mostly used both sea and paddy field as habitat in the winter season and utilized paddy fields more during the nighttime and than the daytime. We concluded that the home-range and habitat of pintails in the winter could be used as the reference data for the preservation of species, management of habitats, and coping with a breakout of HPAI.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.297-307
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• 2010

Recently, maintenance engineering and technology for civil and building structures have begun to draw big attention and actually the number of structures that need to be evaluate on structural safety due to deterioration and performance degradation of structures are rapidly increasing. When stiffness is decreased because of deterioration of structures and member cracks, dynamic characteristics of structures would be changed. And it is important that the damaged areas and extent of the damage are correctly evaluated by analyzing dynamic characteristics from the actual behavior of a structure. In general, typical measurement instruments used for structure monitoring are dynamic instruments. Existing dynamic instruments are not easy to obtain reliable data when the cable connecting measurement sensors and device is long, and have uneconomical for 1 to 1 connection process between each sensor and instrument. Therefore, a method without attaching sensors to measure vibration at a long range is required. The representative applicable non-contact methods to measure the vibration of structures are laser doppler effect, a method using GPS, and image processing technique. The method using laser doppler effect shows relatively high accuracy but uneconomical while the method using GPS requires expensive equipment, and has its signal's own error and limited speed of sampling rate. But the method using image signal is simple and economical, and is proper to get vibration of inaccessible structures and dynamic characteristics. Image signals of camera instead of sensors had been recently used by many researchers. But the existing method, which records a point of a target attached on a structure and then measures vibration using image processing technique, could have relatively the limited objects of measurement. Therefore, this study conducted shaking table test and field load test to verify the validity of the method that can measure multi-point displacement responses of structures using image processing technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.363-371
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• 2023

To construct a ship, blocks of various sizes must be moved and erected . In this process, lugs are used such that they match the block fastening method and various functions suitable for the characteristics of each shipyard facility. The sizes and shapes of the lugs vary depending on the weight and shape of the block structures. The structure is reinforced by welding the doubling pads to compensate for insufficient rigidity around the holes where the shackle is fastened. As for the method of designing lugs according to lifting loading conditions, a simple calculation based on the beam theory and structural analysis using numerical modeling are performed. In the case of the analytical method, a standardized evaluation method must be established because results may differ depending on the type of element and modeling method. The application of this ambiguous methodology may cause serious safety problems during the process of moving and turning-over blocks. In this study , the effects of various parameters are compared and analyzed through numerical structural analysis to determine the modeling conditions and evaluation method that can evaluate the actual structural response of the lug. The modeling technique that represents the plate part and weld bead around the lug hole provides the most realistic behavior results. The modeling results with the same conditions as those of the actual lug where only the weld bead is connected to the main body of the lug, showed a lower ulimated strength compared with the results obtained by applying the MPC load. The two-dimensional shell element is applied to reduce the modeling and analysis time, and a safety working load was verified to be predicted by reducing the thickness of the doubling pad by 85%. The results of the effects of various parameters reviewed in the study are expected to be used as good reference data for the lug design and safe working load prediction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.120-129
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• 2023

To evaluate the vertical loads on railway bridges, conventional load tests are typically conducted. However, these tests often entail significant costs and procedural challenges. Railway conditions involve nearly identical load profiles due to standardized rail systems, which may appear straightforward in terms of load conditions. Nevertheless, this study aims to validate load tests conducted under operational train conditions by comparing the results with those obtained from conventional load tests. Additionally, static and dynamic structural behaviors are extracted from the measurement data for evaluation. To ensure the reliability of load testing, this research demonstrates feasibility through comparisons of existing measurement data with sensor attachment locations, train speeds, responses between different rail lines, tendency analysis, selection of impact coefficients, and analysis of natural frequencies. This study applies to the Dongho Railway Bridge and verifies the applicability of the proposed method. Ten operational trains and 44 sensors were deployed on the bridge to measure deformations and deflections during load test intervals, which were then compared with theoretical values. The analysis results indicate good symmetry and overlap of loads, as well as a favorable comparison between static and dynamic load test results. The maximum measured impact coefficient (0.092) was found to be lower than the theoretical impact coefficient (0.327), and the impact influence from live loads was deemed acceptable. The measured natural frequencies approximated the theoretical values, with an average of 2.393Hz compared to the calculated value of 2.415Hz. Based on these results, this paper demonstrates that for evaluating vertical loads, it is possible to measure deformations and deflections of truss railway bridges through load tests under operational train conditions without traffic control, enabling the calculation of response factors for stress adjustments.

• Journal of Chest Surgery
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• v.41 no.3
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• pp.320-328
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• 2008

Background: Numerous surgical devices for mitral repair have been used in the past with good results. In this study we describe a simple annuloplasty technique with using a new device ($Mitracon^{(R)}$). The aim of this study was to assess its efficacy and surgical results with using $Mitracon^{(R)}$. Material and Method: From May 2003 to October 2005, 46 patients (21 women and 25 men (mean age of $51.4{\pm}17.8$ years) with mitral regurgitation from various causes were treated with either the $Mitracon^{(R)}$ (the $Mitracon^{(R)}$ group) or the Capentier Edward rigid ring (the CE group). The median follow-up duration was 18.9 months. Result: The mean grade of mitral regurgitation before and immediately after surgery in the $Mitracon^{(R)}$ group and the CE group decreased from $3.2{\pm}0.8$ to $0.6{\pm}0.7$ and $3.4{\pm}0.7$ to $0.3{\pm}0.5$, respectively. There were no significant changes in the ejection fraction either between the two groups or before and immediately after surgery. No deaths were seen in either group. Early postoperative echocardiography of all 46 patients showed only trivial mitral regurgitation or none at all. Echocardiography at a median of 18.9 months also showed no progression in mitral regurgitation. The mean grade of mitral regurgitation in the $Mitracon^{(R)}$ group at this time point decreased from $3.2{\pm}0.8$ to $0.8{\pm}0.7$ (p<0.05). The CE group also showed a similar degree of decrease from $3.4{\pm}0.7$ to $0.3{\pm}0.6$ (p<0.05). The mitral valve area in the $Mitracon^{(R)}$ group at 1 year follow-up was $3.3{\pm}0.9cm^2$. The mitral valve area in the CE group was $2.7{\pm}0.6cm^2$. The mean mitral pressure gradient in the $Mitracon^{(R)}$ group at 1 year follow-up was $3.1{\pm}1.3$ mmHg. The mean pressure gradient in the CE group was $4.5{\pm}2.1$ mmHg, although any statistical significant difference for this between the groups was not reached. Conclusion: The present study showed the described technique to be safe and effective in the intermediate term. Because long term results are unavailable, a more extensive prospective randomized multicenter trial may be warranted to determine whether this procedure should be generally applied for repair of mitral valve disease.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.30-41
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• 2007

Purpose: Bone metastasis in breast cancer patients are usually assessed by conventional Tc-99m methylene diphosphonate whole-body bone scan, which has a high sensitivity but a poor specificity. However, positron emission tomography with $^{18}F-2-deoxyglucose$ (FDG-PET) can offer superior spatial resolution and improved specificity. FDG-PET/CT can offer more information to assess bone metastasis than PET alone, by giving a anatomical information of non-enhanced CT image. We attempted to evaluate the usefulness of FDG-PET/CT for detecting bone metastasis in breast cancer and to compare FDG-PET/CT results with bone scan findings. Materials and Methods: The study group comprised 157 women patients (range: $28{\sim}78$ years old, $mean{\pm}SD=49.5{\pm}8.5$) with biopsy-proven breast cancer who underwent bone scan and FDG-PET/CT within 1 week interval. The final diagnosis of bone metastasis was established by histopathological findings, radiological correlation, or clinical follow-up. Bone scan was acquired over 4 hours after administration of 740 MBq Tc-99m MDP. Bone scan image was interpreted as normal, low, intermediate or high probability for osseous metastasis. FDG PET/CT was performed after 6 hours fasting. 370 MBq F-18 FDG was administered intravenously 1 hour before imaging. PET data was obtained by 3D mode and CT data, used as transmission correction database, was acquired during shallow respiration. PET images were evaluated by visual interpretation, and quantification of FDG accumulation in bone lesion was performed by maximal SUV(SUVmax) and relative SUV(SUVrel). Results: Six patients(4.4%) showed metastatic bone lesions. Four(66.6%) of 6 patients with osseous metastasis was detected by bone scan and all 6 patients(100%) were detected by PET/CT. A total of 135 bone lesions found on either FDG-PET or bone scan were consist of 108 osseous metastatic lesion and 27 benign bone lesions. Osseous metastatic lesion had higher SUVmax and SUVrel compared to benign bone lesion($4.79{\pm}3.32$ vs $1.45{\pm}0.44$, p=0.000, $3.08{\pm}2.85$ vs $0.30{\pm}0.43$, p=0.000). Among 108 osseous metastatic lesions, 76 lesions showed as abnormal uptake on bone scan, and 76 lesions also showed as increased FDG uptake on PET/CT scan. There was good agreement between FDG uptake and abnormal bone scan finding (Kendall tau-b : 0.689, p=0.000). Lesion showed increased bone tracer uptake had higher SUVmax and SUVrel compared to lesion showed no abnormal bone scan finding ($6.03{\pm}3.12$ vs $1.09{\pm}1.49$, p=0.000, $4.76{\pm}3.31$ vs $1.29{\pm}0.92$, p=0.000). The order of frequency of osseous metastatic site was vertebra, pelvis, rib, skull, sternum, scapula, femur, clavicle, and humerus. Metastatic lesion on skull had highest SUVmax and metastatic lesion on rib had highest SUVrel. Osteosclerotic metastatic lesion had lowest SUVmax and SUVrel. Conclusion: These results suggest that FDG-PET/CT is more sensitive to detect breast cancer patients with osseous metastasis. CT scan must be reviewed cautiously skeleton with bone window, because osteosclerotic metastatic lesion did not showed abnormal FDG accumulation frequently.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.44-49
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• 2005

Although thymomas are relatively common mediastinal tumors, to date not only has a universal system of pathologic classification not been established but neither has a clearly defined predictable relationship between treatment and prognosis been made. Recently, a new guideline for classification was reported by WHO, and efforts, based on this work, have been made to better define the relationship between treatment and pro­gnostic outcome. In the present study a comparative analysis between the WHO classification and Masaoka stage system with the clinical disease pattern was conducted. Material and Method: A total of 98 patients undergoing complete resection for mediastinal thymoma between Juanuary 1993 and June 2003 were included in the present study. The male female ratio was 48 : 50 and the mean age at operation was $49.6{\pm}13.9\;years.$ A retrospective analytic comparison studying the relationship between the WHO classification and the Masaoka stage system with the clinical disease pattern of thymoma was conducted. Pathologic slide specimens were carefully examined, details of postoperative treatment were documented, and a relationship with the prognostic outcome and recurrence was studied. Result: There were 7 patients in type A according to the WHO system of classification, 14 in AB, 28 in B 1, 23 in B2, 18 in B3, and 9 in type C. The study of the relationship between the Masaoka stage and WHO classification system showed 4 patients to be in WHO system type A, 7 in type AB, 22 in B 1, 17 in B2, and 3 in type B3 among 53 $(54{\%})$ patients shown to be in Masaoka stage I. Among 28 $(28.5{\%})$ patients in Masaoka stage II system, there were 2 patients in type A, 7 in AB, 4 in B 1, 2 in B2, 8 in B3, and 5 in type C. Among 15 $(15.3{\%})$ in Masaoka stage III, there were 1 patient in type B1, 3 in B2, 7 in B3, and 4 in type C. Finally, among 2 $(2{\%})$ patients found to be in Masaoka stage IV there was 1 patient in type B1, and 1 in type B2. The mean follow up duration was $28{\pm}6.8$ months. There were 3 deaths in the entire series of which 2 were in type B2 (Masaoka stages III and IV), and 1 was in type C (Masaoka stage II). Of the patients that experienced relapse, 6 patients remain alive of which 2 were in type B2 (Masaoka III), 2 in type B3 (Masaoka I and III) and 2 in type C (Masaoka stage II). The 5 year survival rate by the Kaplan-Meier method was $90{\%}$ for those in type B2 WHO classification system, $87.5{\%}$ for type C. The 5 year freedom from recurrence rate was $80.7{\%}$ for those in WHO type B2, $81.6{\%}$ for those in type B3, and $50{\%}$ for those in type C. By the Log-Rank method, a statistically significant correlation between survival and recurrence was found with the WHO system of classification (p<0.05). An analysis of the relationship between the WHO classification and Masaoka stage system using the Spearman correction method, showed a slope=0.401 (p=0.023), showing a close correlation. Conclusion: As type C of the WHO classification system is associated with a high postoperative mortality and recurrence rate, aggressive treatment postoperatively and meticulous follow up are warranted. The WHO classification and Masaoka stage system were found to have a close relationship with each other and either the WHO classification method or the Masaoka stage system may be used as a predict prognostic outcome of Thymoma.