• Ecology and Resilient Infrastructure
• /
• v.3 no.2
• /
• pp.117-125
• /
• 2016

Current cities encounter various types of water problems due to rapid urbanization and climate change. The increasing significance of urban water problems calls for the establishment of resilient alternatives to prevent and minimize social loss that results from these phenomena. As a background research for establishing resilient infrastructures for the mitigation of urban water problems, we evaluated the robustness of structural alternatives for urban flood as a representative case. Combining the robustness index (RI) and the cost index (CI), we suggested the robustness-cost index (RCI) as an indicator of the robustness of structural alternatives, and applied the index to assess the existing infrastructures and structural alternatives (i.e., sewer network expansion, additional storage tank construction, and green roof construction) at a site prone to floods located around Gangnam-station, Seoul, Korea. At a rainfall intensity frequency range of 2 to 20 years, the usage of a storage tank and a green roof showed relatively high RCI value, with a variation of an alternative showing greater RCI between the two depending on the size of design rainfall. For a rainfall intensity frequency of 30 years, installing a storage tank with some green roofing was the most resilient alternative based on the RCI value. We proposed strategies for establishing resilient infrastructures for the mitigation of urban floods by evaluating the robustness of existing infrastructures and selecting optimal structural alternatives with the consideration of scales of design disaster.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1522-1526
• /
• 2007

최근 영국의 Institute of Hydrology에서는 Generalized logistic (GL) 분포형을 홍수빈도해석시 GEV 분포형을 대체하는 분포형으로 추천한 바 있으며, 그로 인해 GL 분포형의 사용이 증가하고 있는 추세이다. 하지만 아직 그 사용빈도에 반하여 분포형 자체의 특성, 그 중에서도 확률홍수량의 근사적 분산에 관한 연구는 거의 이루어지지 않았다. 따라서 본 연구에서는 최우도법을 이용하여 GL 분포형의 확률홍수량에 대한 근사적 분산에 관한 연구를 수행하였으며, 이를 표본 크기, 재현기간, 매개변수들의 함수로 나타내었다. 또한 확률홍수량의 근사적 분산의 적용성을 검토하기 위해 Monte Carlo 모의실험을 수행하였으며, 모의실험은 형상 매개변수$(\beta)$가 $\pm0.5$이면 gamma function으로 인하여 표본 크기에 관계없이 분산값이 무한대에 가까워지므로 형상매개변수의 범위는 $-0.5{\leq}{\beta}{\leq}+0.5$로 제한하였다. 모의결과 최우도법에 의해 계산된 분산식은 형상매개변수 $-0.25{\leq}{\beta}{\leq}+0.5$의 범위에서 비교적 잘 맞는 것을 확인할 수 있었으며, 기존에 알려진 대로 표본크기가 크면 클수록 정확해지는 것을 알 수 있다. 또한 표본크기가 작은 경우 형상매개변수 전 범위에서 정확도가 떨어지는 것을 확인할 수 있으며, 최우도법의 경우 표본크기가 작은 경우를 제외하고 $-0.25{\leq}{\beta}{\leq}+0.5$ 범위에서 quantile 산정시 quantile이 약간 과다추정되는 경향이 있는 것을 알 수 있으며, 이는 분산이 과다 추정되는 결과를 초래하며 이로 인해 해석해보다 약간씩 큰 값을 나타내는 것으로 판단되었다..이 극단적인 선정적인 폭력성에 탐닉하게 되는 경향이 있다. 현실은 결코 아름답지 못하고, 행복하게 살 수 없다는 것에 대한 깨달음에서 기인한다. 욕구불만의 강도가 심해질수록 폭력성은 더욱 강하게 나타나는데 개인에게서 뿐만 아니라 가족, 동료, 사회 단체나 종교, 국가간에도 집단적으로도 발생하게 된다. 사회적으로 볼 때 폭력은 용인되는 것이 아니므로 도덕적으로 절제를 하거나 상대방과 적절한 타협과 조정을 필요로 한다. 그러나 절제의 한계를 넘어선다고 생각되거나, 조정의 노력이 불가능하거나, 실패했을 때 폭력적인 행동으로 나타나게 된다. 리차즈(I.A Richards)는 분노와 공포는 일단 겉잡을 수 없는 경향이 있다고 하면서 오늘날 폭력에 대한 요구가 일상의 정서 생활에 있어, 억압을 통한, 빈곤함을 반영하고 있지 않은지 생각해봐야 할 것이라고 충고한다. 조성 가이드라인(안)을 제시하였다.EX>$\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감소를 초래하였을 것으로 사료된다. 셋째, 경기도 광주에서 백자관요가 운영되었으므로 지방인 상주지역에도 더 이상 백자를 조달받을 필요가 없이, 일반 지방관아와 서민들의

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.29-35
• /
• 2011

This research proposes the suitable method for estimating the future probable rainfall based in 2100 on the observed rainfall data from main climate observation stations in Korea and the rainfall data from the A1B climate change scenario in the Korea Meteorological Administration. For all those, the frequency probable rainfall in 2100 was estimated by the relationship between average values of 24-hours annual maximum rainfalls and related parameters. Three methods to estimate it were introduced; First one is the regressive analysis method by parameters of probable distribution estimated by observed rainfall data. In the second method, parameters of probable distribution were estimated with the observed rainfall data. Also the rainfall data till 2100 were estimated by the A1B scenario of the Korea Meteorological Administration. Last method was that parameters of probable distribution and probable rainfall were estimated by the A1B scenario of the Korea Meteorological Administration. The estimated probable rainfall by the A1B scenario was smaller than the observed rainfall data, so it is required that the estimated probable rainfall was calibrated by the quantile mapping method. After that calibration, estimated probable rainfall data was averagely became approximate 2.3 to 3.0 times. When future probable rainfall was the estimated by only observed rainfall, estimated probable rainfall was overestimated. When future probable rainfall was estimated by the A1B scenario, although it was estimated by similar pattern with observed rainfall data, it frequently does not consider the regional characteristics. Comparing with average increased rate of 24-hours annual maximum rainfall and increased rate of probable rainfall estimated by three methods, optimal method of estimated future probable rainfall would be selected for considering climate change.

• Journal of the Korean Geosynthetics Society
• /
• v.22 no.1
• /
• pp.87-96
• /
• 2023

There are a lot of difference between the surface settlement and the differential settlement measured at the Busan New Port, where the dredged and reclaimed clay layer exists and below the clay is originally thickly distributed. To find the cause and solution of this, the actual conditions of each differential settlement used for the soft ground improvement, characteristics, installation method, measurement frequency, measurement data management, and data analysis of each type were considered. In the deep soft ground improvement work where large deformation occurs, the bending deformation of the screw-type differential settlement gauge is less than that of other types of measuring instruments, so there is less risk of loss, and the reliability of data is relatively high as the instruments are installed by drilling for each stratum. Since the greater the amount of high-precision settlement measurement data, the higher the settlement analysis precision. It is necessary to manage with higher criteria than the measurement frequency suggested in the standard specification. For the data management of the differential settlement gauge, it is desirable to create graphs of the settlement and embankment height of the relevant section over time, such as surface, differential, and settlement of pore water pressure gauge for each point. In the case of multi-layered ground with different compression characteristics, it is more appropriate to perform settlement analysis by calculating the consolidation characteristics of each stratum using a differential settlement data.

• Journal of Yeungnam Medical Science
• /
• v.24 no.2
• /
• pp.216-231
• /
• 2007

Background : An acceleration or deceleration of the heart rate (HR), which reflects autonomic effects, is observed before the onset of paroxysmal atrial fibrillation (PAF). The purpose of this study was to assess the discrepancy in the autonomic interactions before the onset of PAF for different patterns of change in the HR. Materials and Methods : From 105 Holter tapes with the PAF recorded, 55 episodes (42 patients, 34 men, $58{\pm}12$ years) of PAF (>5 min), preceded by a sinus rhythm for more than 1 hour, were selected and submitted to time-domain and frequency-domain HR variability analyses. Fifty-five episodes were divided into 2 groups: group A PAF (n=30) with acceleration of the HR during the last 2 minutes before the PAF and group B (n=25) with deceleration of the HR. Results : A significant linear decrease in the mean R-R interval was observed in group A ($924{\pm}30$ to $835{\pm}28ms$, $P$=0.001) and an increase from $831{\pm}32$ to $866{\pm}31ms$ in group B PAF episodes ($P$=0.046). In the frequency-domain analyses, the LF/HF ratio exhibited a progressive linear increase before the PAF in group A ($P$=0.005). The HF normalized units (HFnu) and natural logarithm-transformed HF ($In$HF) values decreased from $30.8{\pm}4.0$ to $16.1{\pm}1.8$ ($P$=0.003) and $4.49{\pm}0.25$ to $4.07{\pm}0.22$ ($P$=0.001), respectively. Contrary to the results in group A, a significant increase in the HF components (HFnu and $In$HF) (from $22.6{\pm}3.2$ to $30.2{\pm}4.0$, $P$=0.005, and $4.27{\pm}0.27$ to 4.75 0.33, $P$=0.001, respectively) and a resultant decrease in the LF/HF ratio were observed in group B PAF episodes. No significant changes were observed in the LF components in either PAF group. Conclusion : Autonomic stimuli leading to an acceleration or deceleration of the HR before the onset of AF are due to parasympathetic modulation. Parasympathetic modulation plays a key role in the initiation of PAF.

• Tuberculosis and Respiratory Diseases
• /
• v.41 no.5
• /
• pp.504-512
• /
• 1994

Background: It is well known that severe hypoxemia is often associated with liver cirrhosis without preexisting cardiac or pulmonary diseases. Pulmonary vascular impairments, more specifically, intrapulmonary shunting have been considered as a major mechanism. Intrapulmonary shunting arises from pulmonary vascular dilatation at the precapillary level or direct arteriovenous communication and has relationship with the characteristic skin findings of spider angioma. However, these results are mainly from Western countries where alcoholic and primary biliary cirrhosis are dominant cuases of cirrhosis. It is uncertain that the same is true in viral hepatitiss associated liver cirrhosis, which is dominant causes of liver cirrhosis in Korea. We investigated the incidences of hypoxemia and orthodeoxia in Korean cirrhotic patients dominantly composed of postnecrotic cirrhosis and the significance of intrapulmonary shunting as the suggested mechanism of hypoxemia, Method: We performed the arterial blood gas analysis separately both at the supine and errect position in 48 stable cirrhotic patients without the evidences of severe complications such as ascites, variceal bleeding, and hepatic coma. According to the results of arterial blood gas analysis, all patients were divided into hypoxemic and normoxemic group. In each group, pulmonary function test and Tc-99m-MAA whole body scan were performed. The shunting fraction was calculated based on the fact that the sum of cerebral and bilateral renal blood flow is 32% of the systemic blood flow. Results: The hypoxemia of $PaO_2$ less than 80 mmHg was observed in 9 patients(18.8%) and Orthodeoxia more than 10 mmHg was observed in 8 patients(16.7%). But there was no patient with significant hypoxemia of $PaO_2$ less than 60 mmHg. $PaO_2$ was significantly decreased in the patients with spider angioma than the pathients without spider angioma and showed no correlation with the serologic type and severities of liver function test findings. Any parameters of pulmonary function test did not demonstrate the difference between normoxemic and hypoxemic group. But hypoxemic group showed significantly increased shunt fraction of $11.4{\pm}4.1%$ than normoxemic group of $4.1{\pm}2.0%$ (p<0.05). Conclusions: Hypoxemia is not infrequently observed complication in liver cirrhosis and intrapulmonary shunting is suggested to p1ay a major ro1e in the development of hypxemia. But there was no great likelihood of clinically significant hypoxemia in our domestic cirrhotic patients predominantly composed of postnecrotic type.

• Journal of KIISE:Databases
• /
• v.37 no.4
• /
• pp.177-184
• /
• 2010

In these day, many data including sensor, delivery, credit and stock data are generated continuously in massive quantity. It is difficult to learn from these data because they are large in volume and changing fast in their concepts. To handle these problems, learning methods based in sliding window methods over time have been used. But these approaches have a problem of rebuilding models every time new data arrive, which requires a lot of time and cost. Therefore we need very simple incremental learning methods. Bayesian method is an example of these methods but it has a disadvantage which it requries the prior knowledge(probabiltiy) of data. In this study, we propose a learning method based on attribute values. In the proposed method, even though we don't know the prior knowledge(probability) of data, we can apply our new method to data. The main concept of this method is that each attribute value is regarded as an expert learner, summing up the expert learners lead to better results. Experimental results show our learning method learns from data very fast and performs well when compared to current learning methods(decision tree and bayesian).

• Korean Journal of Remote Sensing
• /
• v.38 no.5_3
• /
• pp.901-912
• /
• 2022

The frequency of disasters is increasing due to global climate change, and unusual heavy rains and rainy seasons are occurring in Korea. Periodic monitoring and rapid detection are important because these weather conditions can lead to drought and flooding, causing secondary damage. Although research using optical images is continuously being conducted to determine the waterbody, there is a limitation in that it is difficult to detect due to the influence of clouds in order to detect floods that accompany heavy rain. Therefore, there is a need for research using synthetic aperture radar (SAR) that can be observed regardless of day or night in all weather. In this study, using Sentinel-1 SAR images that can be collected in near-real time as open data, the UNet model among deep learning algorithms that have recently been used in various fields was applied. In previous studies, waterbody detection studies using SAR images and deep learning algorithms are being conducted, but only a small number of studies have been conducted in Korea. In this study, to determine the applicability of deep learning of SAR images, UNet and the existing algorithm thresholding method were compared, and five indices and Sentinel-2 normalized difference water index (NDWI) were evaluated. As a result of evaluating the accuracy with intersect of union (IoU), it was confirmed that UNet has high accuracy with 0.894 for UNet and 0.699 for threshold method. Through this study, the applicability of deep learning-based SAR images was confirmed, and if high-resolution SAR images and deep learning algorithms are applied, it is expected that periodic and accurate waterbody change detection will be possible in Korea.

• Journal of Cadastre & Land InformatiX
• /
• v.48 no.2
• /
• pp.79-98
• /
• 2018

The purpose of this study is to suggest a model analysing spatio-temporal characteristics of the civil complaints for the officially assessed land price based on big data mining. Specifically, in this study, the underlying reasons for the civil complaints were found from the spatio-temporal perspectives, rather than the institutional factors, and a model was suggested monitoring a trend of the occurrence of such complaints. The official documents of 6,481 civil complaints for the officially assessed land price in the district of Jung-gu of Incheon Metropolitan City over the period from 2006 to 2015 along with their temporal and spatial poperties were collected and used for the analysis. Frequencies of major key words were examined by using a text mining method. Correlations among mafor key words were studied through the social network analysis. By calculating term frequency(TF) and term frequency-inverse document frequency(TF-IDF), which correspond to the weighted value of key words, I identified the major key words for the occurrence of the civil complaint for the officially assessed land price. Then the spatio-temporal characteristics of the civil complaints were examined by analysing hot spot based on the statistics of Getis-Ord $Gi^*$. It was found that the characteristic of civil complaints for the officially assessed land price were changing, forming a cluster that is linked spatio-temporally. Using text mining and social network analysis method, we could find out that the occurrence reason of civil complaints for the officially assessed land price could be identified quantitatively based on natural language. TF and TF-IDF, the weighted averages of key words, can be used as main explanatory variables to analyze spatio-temporal characteristics of civil complaints for the officially assessed land price since these statistics are different over time across different regions.

• Tuberculosis and Respiratory Diseases
• /
• v.47 no.1
• /
• pp.42-49
• /
• 1999

Background: In patients with chronic obstructive pulmonary disease(COPD). it is well known that hypoxemia increases the frequency of VPB, which is associated with the poor prognosis such as sudden death. The aim of this study is to evaluate the effect of short and long-term low flow oxygen therapy on the development of VPBs in patients with COPD by correcting the hypoxemia. Method: In 19 patients with COPD, oxygen saturation and VPB's were monitored by pulse oxymeter and 24-hour Holter EKG, with room air and oxygen saturation and VPB's were monitored on the 1st and on the 8th day during oxygen therapy with nasal prong (2L/min). Results : The arterial oxygen saturation was significantly higher on the 1st day of oxygen therapy compared with breathing room air, and was also higher on the 8th day of oxygen therapy than on the 1st day. We found that there was significant correlation between the lowest value of the arterial oxygen saturation and the mean value of the arterial oxygen saturation. The number of VPB's per hour was significantly lower on the 1st day of oxygen therapy compared with breathing room air, and also lower on the 8th day of oxygen therapy than on the 1st day. Our results showed positive correlation between the decrease in the frequency of VPB's and the increase in the lowest arterial oxygen saturation, even though correlation was not significant(p=0.056). Conclusion: With oxygen therapy, the arterial oxygen saturation was increased and the number of VPB's was decreased. Long-term oxygen therapy more than 7days, would be helpful to decrease the number of VPB' s in patients with COPD.