• Archives of Plastic Surgery
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• v.45 no.2
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• pp.146-151
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• 2018

Background A persistent problem in autologous breast reconstruction in skin-sparing mastectomies is skin restoration after skin necrosis or secondary oncological resection. As a solution to facilitate reconstruction, skin banking of free-flap skin has been proposed in cases where the overlying skin envelope must be resected, as this technique spares the patient an additional donor site. Herein, we present the largest series to date in which this method was used. We investigated its safety and the possibility of skin banking for prolonged periods of time. Methods All skin-sparing mastectomies and immediate autologous breast reconstructions from December 2009 until June 2013 at our institution were analysed. Results We identified 31 patients who underwent 33 free flap reconstructions in which skin banking was performed. Our median skin banking period was 7 days, with a maximum duration of 171 days. In 22.5% of cases, the banked skin was used to reconstruct overlying skin defects, and in 9.6% of cases to reconstruct the nipple-areolar complex. Microbiological and histological investigations of the banked skin revealed neither clinical infections nor malignancies. Conclusions In situ skin banking, even for prolonged periods of time, is a safe and cost-effective method to ensure that skin defects due to necrosis or secondary oncological resection can be easily reconstructed.

• The Journal of Engineering Geology
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• v.13 no.2
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• pp.227-238
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• 2003

Understanding of a creep behavior in rocks under a constant load, due to visco-elastic properties of rock, is an essential element to predict a long term ground deformation. In order to clarify the creep characteristics of the mudstone in Duho formation at Pohang basin, deposited during Tertiary, a series of laboratory tests including physical properties, unconfined compressive strength and uniaxial creep tests, was performed. The mudstone showed a higher creep potential due to 26% of clay minerals such as illite and chlorite. The unconfined compressive strength of the rock was $462{\;}kg/\textrm{cm}^2$ in average, and four creep tests were performed under constant stress of 40 to 70 % of the strength. The creep constants in the empirical and theoretical equations were deduced from the time-strain curves obtained from the tests. Among the several equations, the empirical equation proposed by Griggs and theoretical equation of Burger’s model are appreciated as the best one to express the creep behavior of the mudstone. Instantaneous elastic strain was linearly increased with stress level but strain velocity during the first creep is decreased with a similar pattern by time lapse regardless the stress level.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.85-97
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• 2005

Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exist concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, especially when used as part of permanent structures. In view of these concerns, in this paper time-dependent deformation characteristics of geosynthetic reinforced soil under sustained and/or repeated loads were investigated using a series of plane strain compression tests on geogrid reinforced weathered granite soil specimens. The results indicate that sustained or repeated loads can yield appreciable magnitudes of residual deformations, and that the residual deformations are influenced not only by the loading characteristics but by the mechanical properties of geogrid. It is also found that the preloading technique can be effectively used in controlling residual deformations of reinforced soils subjected to sustained and/or repeated loads.

• Ocean and Polar Research
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• v.25 no.1
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• pp.63-74
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• 2003

The build-up of the heat field in shallow coastal water due to a point source has been investigated using an analytical solution of a time-integral form derived by extending the solutions by Holley(1969) and also presented in Harleman (1971). The uniform water depth is assumed with non-isotropic turbulent dispersion. The alongshore-flow is assumed to be uni-directional, spatially uniform and oscillatory. Due to the presence of the oscillatory alongshore-flow, the heat build-up occurs in an oscillatory manner, and the excess temperature thereby fluctuates in that course and even in the quasi-steady state. A series of calculations reveal that proper choices of the decay coefficient as well as dispersion coefficients are critical to the reliable prediction of the excess temperature field. The dispersion coefficients determine the absolute values of the excess temperature and characterize the shoreline profile, particularly within the tidal excursion distance, while the decay coefficient determines the absolute value of the excess temperature and the convergence rate to that of the quasi-steady state. Within the e-folding time scale $1/k_d$ (where $k_d$ is the heat decay coefficient), heat build-up occurs more than 90% of the quasi-steady state values in a region within a tidal excursion distance (L), while occurs increasingly less the farther we go to the downstream direction (about 80% at 1.25L, and 70% at 1.5L). Calculations with onshore and offshore discharges indicate that thermal spreading in the direction of the shoreline is reduced as the shoreline constraint which controls the lateral mixing is reduced. The importance of collecting long-term records of in situ meteorological conditions and clarifying the definition of the heat loss coefficient is addressed. Interactive use of analytical and numerical modeling is recommended as a desirable way to obtain a reliable estimate of the far-field excess temperature along with extensive field measurements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.135-139
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• 1993

It was found in a series of test sections constructed in Houston, Texas that (1) concrete placement in hot season resulted in much more early-age cracks than that in cool season, and that, (2) for the hot season placement, pavements placed in the morning showed more early-age cracks than those placed in the afternoon. Early-age cracks, in this study, are defined as cracks occurring within a few days after construction. Since the early-age cracks have a tendency to be meandering and the crack widths are relatively wide, they may give an adverse effect on the long-term performance of the pavement. The objectives of this study are to recognize the effects of placement time on the early-age crack patterns and to find the reason of the effects. The effects are explained in this study by relating hydration of cement and surrounding temperature conditions.

• Perspectives in Nursing Science
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• v.11 no.1
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• pp.63-73
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• 2014

Purpose: This study examine the effects of music therapy and phone counseling on postpartum depression and maternal identity in high risk women. Methods: A nonequivalent control group time series research design was employed. Eighteen women comprised the experimental group and seventeen women, the control group. Experimental group received 4 weeks of music therapy and phone counseling. Postpartum depression and maternal identity were measured prior to intervention and on the 1st, 2nd, and 4th weeks after its introduction. Results: The first hypothesis (i.e., "the degree of postpartum depression would be lower in the experimental group than in the control group in a month's time") was not supported (z=-0.47, p=.641). The second hypothesis (i.e., "the degree of maternal identity would be lower in the experimental group than in the control group in a month") was not supported as well (z=1.08, p=.285). Conclusion: There is the need to monitor long-term effects of music therapy and phone counseling on high risk postpartum women, beyond 4 weeks observed in this study. Additionally, the development of music therapy tailored to high risk individuals and systematic phone counseling protocols for postpartum depression is required.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.35-43
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• 2020

Turbidity has various effects on the water quality and ecosystem of a river. High turbidity during floods increases the operation cost of a drinking water supply system. Thus, the management of turbidity is essential for providing safe water to the public. There have been various efforts to estimate turbidity in river systems for proper management and early warning of high turbidity in the water supply process. Advanced data analysis technology using machine learning has been increasingly used in water quality management processes. Artificial neural networks(ANNs) is one of the first algorithms applied, where the overfitting of a model to observed data and vanishing gradient in the backpropagation process limit the wide application of ANNs in practice. In recent years, deep learning, which overcomes the limitations of ANNs, has been applied in water quality management. LSTM(Long-Short Term Memory) is one of novel deep learning algorithms that is widely used in the analysis of time series data. In this study, LSTM is used for the prediction of high turbidity(>30 NTU) in a river from the relationship of turbidity to discharge, which enables early warning of high turbidity in a drinking water supply system. The model showed 0.98, 0.99, 0.98 and 0.99 for precision, recall, F1-score and accuracy respectively, for the prediction of high turbidity in a river with 2 hour frequency data. The sensitivity of the model to the observation intervals of data is also compared with time periods of 2 hour, 8 hour, 1 day and 2 days. The model shows higher precision with shorter observation intervals, which underscores the importance of collecting high frequency data for better management of water resources in the future.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.35-40
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• 2005

Objective : Limited data are available concerning the outcome of the patients with atypical meningioma due to lack of the studies with large series. The authors review atypical meningioma retrospectively and analyzed various parameters concerning its outcome. Methods : Of the 866 meningioma patients treated between 1990 and 2003, pathologically proven 54 atypical meningiomas were reviewed. Various factors of the patients were analyzed, and surgical specimens were re-examined blindly by neuropathologist without any patient information. Extent of surgical resection was determined according to Simpson's classification by reviewing the chart and postoperative scan if possible. Results : Twenty-three [42.6%] had local recurrences during the follow-up, of which 13 [32.5%] of 40 complete excisions and 10 [71.4%] of 14 incomplete excisions. The median time to recurrence was 47 months, and the overall 3-, 5-, and 10-year local control rates were 62.4%, 41.5%, and 31.1%, respectively. Five [9.3%] died during follow-up period. The mean survival time was 123months, and the overall 3-, 5-, and 10-year survival rates were 94.2%, 87.2%, and 78.5%, respectively. The extent of surgical excision was the most significant prognostic factor not for survival but for local control [p=0.2179 and 0.0005, respectively]. Extracranial metastasis was not seen in our cases. Conclusion : Complete surgical excision is the most important factor in improving local control. Careful long-term follow-up is mandatory because atypical meningioma shows a broad range of aggressiveness and natural history.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.179-196
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• 2021

Port congestion rate at Busan Port has increased for three years. Port congestion causes container reconditioning, which increases the dockyard labor's work intensity and ship owner's waiting time. If congestion is prolonged, it can cause a drop in port service levels. Therefore, this study proposed an anomaly detection method using ARIMA(Autoregressive Integrated Moving Average) model with the daily volume data from 2013 to 2020. Most of the research that predicts port volume is mainly focusing on long-term forecasting. Furthermore, studies suggesting methods to utilize demand forecasting in terms of port operations are hard to find. Therefore, this study proposes a way to use daily demand forecasting for port anomaly detection to solve the congestion problem at Busan port.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.491-493
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• 2022

Flood damage due to torrential rains and typhoons is occurring in many parts of the world. In this paper, we propose a water level prediction model using water level, precipitation, and humidity data, which are key parameters for flood prediction, as input data. Based on the LSTM and GRU models, which have already proven time-series data prediction performance in many research fields, different input datasets were constructed using the ASOS(Automated Synoptic Observing System) data and AWS(Automatic Weather System) data provided by the Korea Meteorological Administration, and performance comparison experiments were conducted. As a result, the best results were obtained when using ASOS data. Through this paper, a performance comparison experiment was conducted according to the input data, and as a future study, it is thought that it can be used as an initial study to develop a system that can make an evacuation decision in advance in connection with the flood risk determination model.