• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.88-88
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• 2023

지난 100년 동안 전 지구의 기상 이변이 꾸준히 증가하고 있다. 기후 변화는 도시 홍수 피해에 큰 영향을 끼치는데 급속한 도시화와 이상 기후로 인한 돌발 강우 패턴의 증가는 도시 침수의 취약성을 가중시킨다. 또한 급격한 도시 발전으로 인한 도심지의 불투수율 또한 꾸준히 증가하였다. 특히 2022년 8월 8일에 강남역과 도림천 일대에 내린 기록적인 강우는 기후 변화를 실감하게 하는 사회적 이슈가 되었으며 도심지 미래 수방 대책 변화를 상기시키는 계기가 되었다. 이로 인한 재해 피해에 최소화하기 위해 미래 기후 변화를 고려한 도심지의 새로운 방재 목표강우량 설정이 필요하다. 하지만 전 지구 모형(GCM)의 기후 변화 시나리오는 일 단위(Daily) 상세화 자료를 보편적으로 사용하고 있다. 하지만 이는 단기 강우 자료를 필요로 하는 도시 홍수 모의에서 제대로 활용할 수 없는 한계를 가지고 있다. 따라서 본 연구는 2019년에 발간된 IPCC 6차 평가 보고서(AR6)가 제안하는 SSP(Shared Socioeconomic Pathways, 공통사회경제경로) 시나리오를 기반하여 상세화된 일 단위(Daily) 강우 데이터를 비모수적 통계 기법을 사용하여 시간 단위(Hourly)로 상세화하였다. 또한 지속 시간별 연 최대치 강우를 추출하여 빈도 해석을 통해 도시 유역의 미래 확률 강우량을 제시하였으며, 서울시 상습적인 침수 취약 지역인 도림천 유역에 강우-유출 모형(XP-SWMM)을 사용하여 미래전망 기후 자료인 SSP2-4.5와 SSP5-8.5에 따른 미래 확률 강우 침수 모의를 실시하였다. 본 연구의 결과는 최신 기후 변화 시나리오를 고려한 서울시 방재 성능 목표 강우량 산정에 활용 가능할 것으로 사료되며 미래 강우량 침수 모의를 통해 침수 취약 구역인 도림천 일대 홍수피해의 근거 자료가 되는 것에 의의를 둔다. 또한 치수 분야에서 기후 변화를 고려하기 위해서는 기후 변화 시나리오에 따른 시간 단위 자료의 상세화가 필요함을 시사한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.84-88
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• 2023

This study proposes an automated tilt measurement method using point cloud for buildings. The proposed method consists of two main steps: 1) exterior wall plane extraction, and 2) edge estimation and angle calculation. To validate the performance of the proposed method, the algorithm is applied to a target building, of which the estimated tilt values are compared with those obtained from a total station, a commonly used tool for tilt measurement. The result shows that most estimated tilt values are within the maximum and minimum ranges of the total station measurement, suggesting that the proposed algorithm provides sufficient measurement accuracy. Furthermore, the proposed method is shown to be automated and reliable as well as free from human-induced errors compared to the total station.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.249-260
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• 2024

In recent years, the proportion of medium and small-sized apartments within the housing market has seen a noticeable increase, alongside a corresponding rise in disputes related to construction defects. Such disputes are most prevalent in the finishing works phase of construction, which not only are frequent in occurrence but also impose significant repair costs. Furthermore, there is a noticeable scarcity of research focused on the quality management of finishing work defects prior to the completion of construction. Addressing this issue necessitates a methodology capable of preemptively identifying defects by analyzing their frequency and associated costs across various defect types. Consequently, the aim of this study is to propose a risk assessment methodology by conducting an analysis of defect cases across 3,299 apartment units, considering aspects such as frequency and severity. The outcomes of this research endeavor are expected to offer practical management strategies to enhance the quality of apartment finishing works and serve as an academic foundation for the enhancement of construction management systems pertaining to apartment finishing works.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.164-172
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• 2008

The heat of hydration for early aged mass concrete induces high temperature with the hydration. Control of the temperature difference across a section is an effective strategy to minimize the hydration heat induced cracks for the structures where internal restraint is dominant. The current prevention methods for hydration cracking show some limitations for the control of thermal gradients, and these limitations could make micro and macro cracks in surface and core of concrete. Especially cooling methods can decrease the increasing hydration temperature, but it can not prevent the problem while decreasing temperature. Consequently heating pipes are added simultaneously with the cooling pipes in order to control the temperature gradients between core and surface of the concrete, followed by the finite element analysis (FEA). Based on the FEA, the proposed method using cooling pipe and heating pipes together has been found to be an effective alternative in thermal gradient control, in terms of controlling temperature induced cracks significantly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.3
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• pp.175-182
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• 2008

In this paper, through the study and consideration of the recently prominent monitoring of cable stayed-bridge, practical but reasonable suggested for the evaluation of the probabilistic safety of the bridges using probable measured data from monitoring measurement system. It is shown in the paper that the live load effects can be evaluated using measured data of cable-stayed bridge and this the realistic probabilistic safety of the cable-stayed bridge could be assessed in term of element reliability and system reliability. As a practical method for the evalution of the system reliability of system cable-stayed bridges partial ETA method is uesd, which can find the critical failure path including combined failure modes of cable, deck and pylon. Compared with the conventional safety analysis method, the propsed approach may be considered as the practical method that shows the considerably actual and reasonable results the system redundancy of the structure.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.1
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• pp.37-41
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• 2016

Purpose The importance of quality control by the error to a minimum, which for the purpose of enhancing the reliability of the examination is not be emphasized excess. Currently, most nuclear medicine laboratory are conducting the internal and external quality control, and they are applying the Levey-Jennings or Westgard Multi-Rules by using the commercialized quality control materials. The reliability of the nuclear medicine blood test which affects the diagnosis of patients and the treatment policy is being secured through this quality control activity. Therefore, researchers will evaluate the utility of the statistic quality control using the population distribution of the nuclear medicine blood test conducted targeting the checkup examinees by the additional technique of the reliability improvement. Materials and Methods A statistic analysis was performed about 12 items of the nuclear medicine blood test targeting 41,341 peoples who used the health screening and promotion center in Asan Medical Center from January, 2014 to December, 2014. The results of 12 items of the nuclear medicine blood test was divided into the monthly percentage of three groups: within reference values, over reference, and under reference to analyze the average value of the population distribution, standard deviation, and standard deviation index (SDI). Results The standard deviation of the population distribution mostly showed a result within ${\pm}2SD$ in all groups. However, When the standard deviation of the population distribution represented a result over ${\pm}2SD$, it was confirmed SDI was showing a result of SDI > -2 or SDI > 2. As a result of analyzing the population distribution of 12 items(AFP, CEA, CA19-9, CA125, PSA, TSH, FT4, Anti-Tg-Ab, Anti-TPO-Ab, Calcitonin, 25-OH-VitD3, Insulin) of the nuclear medicine blood part basic test, when SDI of the monthly percentage which deviated from the reference values was over ${\pm}2.0$, CA19-9 September was 2.2, Anti-Tg-Ab may was 2.2, Insulin January was 2.3, Insulin March was 2.4. It was confirmed these cases were attributed to the abnormality of the test reagent (maximum combination rate of isotope reagent declined) and the decline of the test response time. Conclusion The population distribution includes the entire attribute which becomes the study object. It is expected the statistic quality management using the population distribution which was conducted targeting the checkup examinees by dividing into three groups: within reference values, over reference, and under reference by means of this characteristics will be able to play a role of complementing the internal quality control program which is being carried out in the laboratory.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.379-389
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• 2014

The purpose of this study is to optimize the patient(examinee) flow in a health examination center via a simulation model and to improve operational efficiency. Two experimentation scenarios were implemented into the simulation model to determine which proposed scenario provides better improvement in terms of the following performance measures: LOS(Length of Stay), staff utilization, and occupancy level. The simulation results demonstrated that there was no significant difference in response results of two scenarios. Although the original motivation of this study was suggest optimal policy for a patient(examinee) flow, the insight into applying simulation in efficiently managing hospital operations is of more value. Simulation approach is a powerful technique that supports efficient decision-making compared to traditional healthcare management approach based on past experience, feelings, and intuition. Therefore, the proposed experimentation model has wide applicability in healthcare systems.

• Journal of Korea Water Resources Association
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• v.44 no.4
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• pp.295-304
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• 2011

For effective water quality management, it is necessary to secure reliable water quality information. There are many variables that need to be included in a comprehensive practical monitoring network : representative sampling locations, suitable sampling frequencies, water quality variable selection, and budgetary and logistical constraints are examples, especially sampling location is considered to be the most important issues. Until now, monitoring network design for water quality management was set according to the qualitative judgments, which is a problem of representativeness. In this paper, we propose network design system for optimal water quality monitoring using the scientific statistical techniques. Network design system is made based on the SAS program of version 9.2 and configured with simple input system and user friendly outputs considering the convenience of users. It applies to Excel data format for ease to use and all data of sampling location is distinguished to sheet base. In this system, time plots, dendrogram, and scatter plots are shown as follows: Time plots of water quality variables are graphed for identifying variables to classify sampling locations significantly. Similarities of sampling locations are calculated using euclidean distances of principal component variables and dimension coordinate of multidimensional scaling method are calculated and dendrogram by clustering analysis is represented and used for users to choose an appropriate number of clusters. Scatter plots of principle component variables are shown for clustering information with sampling locations and representative location.

• Journal of Korea Water Resources Association
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• v.52 no.12
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• pp.1075-1086
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• 2019

Recently, as the incidence of climate warming and abnormal climate increases, the forecasting of hydrological factors such as precipitation and river flow is getting more complicated, and the risk of water shortage is also increasing. Therefore, this study aims to develop a model for predicting the amount of water intake in mid-term. To this end, the correlation between water intake and meteorological factors, including temperature and precipitation, was used to select input factors. In addition, the amount of water intake increased with time series and seasonal characteristics were clearly shown. Thus, the preprocessing process was performed using the time series decomposition method, and the support vector machine (SVM) was applied to the residual to develop the river intake prediction model. This model has an error of 4.1% on average, which is higher accuracy than the SVM model without preprocessing. In particular, this model has an advantage in mid-term prediction for one to two months. It is expected that the water intake forecasting model developed in this study is useful to be applied for water allocation computation in the permission of river water use, water quality management, and drought measurement for sustainable and efficient management of water resources.

• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.7-16
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• 2000

This paper is focused on verifying time-space repetition of the highway accident and finding the their causes and deterrents. We classify all months into several seasonal groups, develop the model for each seasonal group and analyze the results of these models for Joong-bu highway. The existence of seasonal effect is verified by the analysis or self-organizing map and the accident indices. Agglomerative hierarchical cluster analysis which is used to decide the seasonal groups in accordance with accident patterns, winter group, spring-fall group. and summer group. The accident features of winter group are that the accident rate is high but the severity rate is low. while those of summer group are that the accident rate is low but the severity rate is high. Also, the regression model which is developed to identify the accident Pattern or each seasonal group represents that the season-related factors, such as the amount of rainfall, the amount of snowfall, days of rainfall, days of snowfall etc. are strongly related to the accident pattern of evert seasonal group and among these factors the traffic volume, amount of rainfall. the amount of snowfall and days of freezing importantly affect the local accident Pattern. So, seasonal effect should be considered to the identification of high-risk road section. the development of descriptive and Predictive accident model, the resource allocation model of accident in order to make safety management plan efficient.