• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.2
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• pp.116-127
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• 2002

Most of finite difference numerical models for the simulation of tsunami propagation developed so for are based on the shallow-water equations which are frequently solved by the leap-frog scheme. If the grid size is properly selected, this numerical scheme gives a correct dispersion effect fur constant water depth. However, if the water depth changes, the dispersion effect of tsunamis can not be accurately considered at every grid point in the whole computational domain. In this study we improved the existing two-dimensional dispersion-correction finite difference numerical scheme. The present scheme satisfies the local dispersion relationships of tsunamis propagating over a slowly varying topography while using uniform grid size and time step. To verify the applicability of the improved numerical model, a tsunami due to 1983 East Sea central earthquake is simulated for Korean harbors with the tide gage records such as Sokcho, Mukho, Pohang and Ulsan in the East Sea. Numerical results of the 1983 tsunami are compared with the measured data and the accuracy of the present numerical model is evaluated.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.341-350
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• 2003

Objective: The purpose of this study was to identify dietary factors related to infertility in Korean women through a case-control study. Methods: The case group was composed of 236 women who had been diagnosed as infertility in hospital. The control group of 181 healthy women with children were recruited from local immunization centers. Socio-economic status, medical history, dietary intakes using food frequency questionnaire and stress were surveyed by interview. Anthropometric measurements were made and the causes of infertility were identified through medical records. Fasting blood samples were taken from subgroup of the subjects. Results: The mean age of infertile and control groups was 31.1 and 32.4 years, respectively and the difference was statistically significant. The mean Body Mass Index of infertile women was not significantly different from control women, however, Waist/ Hip Ratio and Triceps Skinfolds Thickness were significantly lower in infertile women than in control women. The dietary intake status was generally satisfactory in both groups. The intakes of energy, protein, fat, carbohydrate, retinol, vitamin B2 and niacin were lower in infertile women than in control women. The infertile women also showed lower intakes of animal foods. No differences were found between two groups in serum concentrations of albumin, hemoglobin, Fe, TIBC, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride, C3, IgA, IL-2, however, infertile women showed higher levels of Zn and IgG. The stress score was higher in infertile women. Conclusions: From the results of this study, dietary factors and nutritional status do not seem to be directly related to infertility. However, the intertile women have lower nutrient intake and lower body fat content than control women. Further researches are needed according to the causes of infertility for long term to establish the relationship between dietary factors and infertility.

• Water for future
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• v.27 no.3
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• pp.45-54
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• 1994

Basic theory of fractal dimension is introduced and performed for the generated time series using the water balance model. The water balance equation over a large area is analyzed at seasonal time scales. In the generation and modification of mesoscale circulation local recycling of precipitation and dynamic effects of soil moisture are explicitly included. Time delay is incorporated in the analysis. Depending on the parameter values, the system showed different senarios in the evolution such as fixed point, limit cycle, and chaotic types of behavior. The stochastic behavior of the generated time series is due to deterministic chaos which arises from a nonlinear dynamic system with a limited number of equations whose trajectories are highly sensitive to initial conditions. The presence of noise arose from the characterization of the incoming precipitation, destroys the organized structure of the attractor. The existence of the attractor although noise is present is very important to the short-term prediction of the evolution. The implications of this nonlinear dynamics are important for the interpretation and modeling of hydrologic records and phenomena.

• Archives of Craniofacial Surgery
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• v.19 no.3
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• pp.194-199
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• 2018

Background: Cases of simultaneous multiple skin cancers in a single patient have become more common. Due to the multiplicity of lesions, reconstruction in such cases is more difficult than after a single lesion is removed. This study presents a series of patients with multiple facial skin cancers, with an analysis of the surgical removal, reconstruction process, and the results observed during follow-up. Methods: We reviewed 12 patients diagnosed with multiple skin cancers on the face between November 2004 and March 2016. The patients' medical records were retrospectively reviewed to identify the type of skin cancer, the site of onset, methods of surgical removal and reconstruction, complications, and recurrence during follow-up. Results: Nine patients had a single type of cancer occurring as multiple lesions, while three patients had different skin cancer types that occurred together. A total of 30 cancer sites were observed in the 12 patients. The most common cancer site was the nose. Thirteen defects were reconstructed with a flap, while 18 were reconstructed with skin grafting. The only complication was one case of recurrence of basal cell carcinoma. Conclusion: Multiple skin cancers are removed by performing Mohs micrographic surgery or wide excision, resulting in multiple defect sites. The authors emphasize the importance of thoroughly evaluating local lesions surrounding the initially-identified lesions or on other sites when reconstructing a large defect which can not be covered by primary closure. Furthermore, satisfactory results can be obtained by using various methods simultaneously regarding the condition of individual patients, the defect site and size, and the surgeon's preference.

• Advances in environmental research
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• v.2 no.2
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• pp.81-98
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• 2013

Mercury (Hg) dynamics in the boreal environment have been a subject of concern in recent decades, due to the exposure of local populations to the contaminant. Land use, because of its impact on mercury inputs, has been highlighted as a key player in the sources and eventual concentrations of the heavy metal. In order to evaluate the impact of watershed disturbances on Hg dynamics in frequently fished, large boreal lakes, we studied sediment cores retrieved at the focal point of eight large lakes of Qu$\acute{e}$bec (Canada), six with watersheds affected by land uses such as logging and/or mining, and two with pristine watersheds, considered as reference lakes. Using a Geographical Information System (GIS), we correlated the recent evolution of land uses (e.g., logging and mining activities) and morphological characteristics of the watershed (e.g., mean slope of the drainage area, vegetation cover) to total Hg concentrations (THg) in sedimentary records. In each core, THg gradually increased over recent years with maximum values between 70 and 370 ng/g, the lowest mercury concentrations corresponding to the pristine lake cores. The Hg Anthropogenic Sedimentary Enrichment Factor (ASEF) values range from 2 to 15. Surprisingly, we noticed that the presence of intense land uses in the watershed does not necessarily correspond to noticeable increases of THg in lake sediments, beyond the normal increment that can be attributed to Hg atmospheric deposition since the beginning of the industrial era. Rather, the terrestrial Hg inputs of boreal lakes appear to be influenced by watershed characteristics such as mean slopes and vegetation cover.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.166-175
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• 2006

Since many years ago and in spite of the existence of national regulations and international conventions ratified by the countries that are conformed the Central American Region (CAR), the seagoing maritime sector of this Region, has developed its activity without any type of safety measures. Therefore, a large number of people are known to die, disappear and suffer from serious injuries each year. These maritime casualties devastate the families affected by these events, and severely impact the local social and economic well-being. While all these accidents occurred in this Region, non government or any other official records are available recording these casualties Due to the lack of any historical written reports about maritime casualties occurred in this Region, the compilation of this type of accidents information and data was carried out directly by the researchers in the field. Also, all the information about the CAR Maritime Organization Components was too compiled by the authors from the respective National Maritimes Authorities. From the compiled information was elaborated the CAR maritime casualties data base and from the analysis of the above data base were determined the main causes of the maritime accidents occurred in the CAR. The lack of safety measures onboard and the ignorance of the presence and influence of atmospheric phenomena were among main factors that had been caused the maritime casualties in this Region. By other hand, from the analysis of the CAR maritime organization components, the existence of one level of organization very similar among them was determinate. The objective of this research was to analyze the role of the CAR maritime organization in the prevention of the occurrence of maritime casualties. The results of this study provides general understanding of the causes of this type of accidents in the CAR and basis for support in improving safety navigation system and measures so that the number of fatalities and maritime accidents may be reduced in the future.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.621-626
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• 2011

Purpose: Implant-based breast reconstruction has multiple advantages such as decreased morbidity, shorter operative time and faster recovery. However, postoperative infection with tissue expander increases medical cost and causes a delay in concurrent antineoplastic treatment. To reduce tissue expander infection, it is important to identify related risk factors and minimize them when possible. Methods: A retrospective review of patient records in a single breast cancer center was performed. Eighty-six tissue expanders were placed in 80 women for postmastectomy breast reconstruction. Variables including patients'age, body mass index (BMI), preoperative breast volume, operation time, drain indwelling time, postoperative seroma/hematoma formation, chemotherapy, and radiation therapy were evaluated. Infection was defined as the status that shows any symptom of local inflammation and identification of pathogens. Representative values were compared through Student's t-test and univariate and multivariate analyses. Results: We examined 86 postmastectomy tissueexpanders which were placed between June 2004 and April 2010. Seven cases of tissue expander infection (8.1%) were identified. The infected tissue expander was removed in three of the cases. The relationship between BMI, and preoperative breast volume and that between infection and non-infection groups were significant ($p$ <0.05). Univariate analysis showed significant association between BMI ($p$=0.023) and preoperative breast volume ($p$=0.037). Multivariate analysis revealed that BMI and preoperative breast volume were independent variables regarding tissue expander infection. Conclusion: Certain characteristics of implant-based breast reconstruction patients increase infection rate of tissue expander. These risk factors should be monitored and evaluated before surgeries for more successful outcome.

• Archives of Plastic Surgery
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• v.47 no.1
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• pp.42-48
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• 2020

Background Methods for identifying local lymph node metastasis in malignant melanoma include sentinel lymph node biopsy (SLNB) and lymph node dissection (LND). In particular, SLNB has been widely used in recent years. This study aimed to retrospectively confirm the adequacy of the current indication criteria for SLNB by applying those criteria to a mixed group of patients who previously received SLNB and LND. Methods This study included 77 patients with malignant melanoma of the extremities and trunk who were monitored for >24 months. The patients were classified according to whether the current indication criteria for SLNB were applicable. The sentinel lymph nodes were evaluated for each group. Patients for whom the indication criteria for SLNB and LND were applicable were analyzed according to whether SLNB or LND was performed. Finally, the outpatient records of these patients were reviewed to evaluate recurrence, metastasis, and prognosis. Results Of the 77 patients, SLNB was indicated according to the current criteria in 60 cases. Among the 60 patients for whom SLNB was indicated, 35 survived the follow-up period disease-free, 21 died during the follow-up period, and four experienced metastasis. The 17 patients for whom SLNB was not indicated had no recurrence or metastasis. Conclusions Patients for whom SLNB was not indicated had no recurrence or metastasis. In cases where SLNB is indicated, the possibility of metastasis and recurrence may be high even if SLNB is negative or LND is performed, so more aggressive treatment and careful follow-up are crucial.

• Journal of Chest Surgery
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• v.44 no.1
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• pp.39-43
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• 2011

Background: Pulmonary sclerosing hemangioma is a rare thoracic tumor, and pathophysiology or clinical course of this tumor is not yet fully described. Furthermore, there is no consensus on the standard operative procedure for this tumor. Material and Methods: Medical records of thirty-two patients, who underwent surgical resection of pulmonary sclerosing hemangioma from 1996 to 2007, were retrospectively reviewed. Results: Nineteen patients underwent lobectomy and thirteen patients underwent limited resection. Video-assisted thoracoscopic surgery was performed in 9 patients in the latter group. Lymph node dissection was done in 21 patients, and one patient was found to have lymph node metastasis of the tumor. There was no postoperative complication, no early death and no tumor-related late mortality. The mean follow-up duration was 39.3 months (2 months~129 months), and all patients were free of local recurrence and distant metastasis during this period. There was no significant difference in patient's characteristics between the two groups, except that the mean hospital stay was shorter in limited resection group than in lobectomy group (p=0.0031). Conclusion: Pulmonary sclerosing hemangioma usually requires surgical resection for both diagnosis and treatment. Limited resection can decrease hospital stay with a surgical outcome comparable to lobectomy, and may be preferred to lobectomy if sufficient resection margin can be achieved.

• Korean Journal of Hydrosciences
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• v.7
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• pp.37-49
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• 1996

This study aims at suggesting an alternative to improve flood controling capacity according to the cument design criteria for the existing Soyanggang Multi-purpose Dam which was constructed 20 years ago as the largest dam in Korea. The peak inflow of the adopted probable maximum flood (PMF) at the time of construction was 13,500 $m^3$/s. However, the newly estimated peak inflow of the PMF is 18,000 $m^3$/s which is 1.34 times bigger than the original one. This is considered to be due to the accumulation of the reliable flood and storm event records after construction, and due to the increasing tendency of the local flood peaks according to the influence of world-wide weather change. The new estimation of the probable maximum precipitation (PMP) was based on the hydro-meteorological method suggested by the guideline of the World Meteorological Organization (WMO). The unit hydrograph which was applied for the estimation of PMF was derived through linear programming algorithm by minimizing the sum of absolute deviations of the calculated and recorded flood hydrographs. In order to adopt the newly estimated PMF as a design flood, following four alternatives were compared : (1) allocation of more flood control space by lowering the normal high water level, (2) construction of a new spillway in addition to the existing spillway, (3) construction of a new dam which has relevant flood control storage at the upstream of the Soyanggang dam, (4) raising the existing dam crest. The preliminary evaluation of these alternatives resulted in that the second alternative is most economic and feasible. So as to stably cope with the newly estimated PMF by meeting all the current functions of the multipurpose dam, a detailed study of an additional spillway tunnel has to be followed.