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For effective hazard mitigation planning and prompt-but-prudent post-disaster responses, it is essential to evaluate the reliability of infrastructure networks accurately and efficiently. A nonsimulation-based algorithm, termed as a recursive decomposition algorithm (RDA), was recently proposed to identify disjoint cut sets and link sets and to compute the network reliability. This paper introduces a ‘selective’ RDA, which preferentially identifies critical disjoint cut sets and link sets to calculate the probabilities of network disconnection events with a significantly reduced number of identified sets. To this end, the original RDA is improved by replacing the shortest path algorithm with an algorithm that identifies the most reliable path, and by using a graph decomposition scheme based on the probabilities associated with the subgraphs. The critical sets identified by the algorithm are also used to compute conditional probability-based importance measures that quantify the relative importance of network components by their contributions to network disconnection events. This paper also introduces a risk assessment framework for lifeline networks based on the use of the selective RDA, which can consider both interevent and intraevent uncertainties of spatially correlated ground motions. The risk assessment framework and the selective RDA are demonstrated by a hypothetical network example, and the gas and water transmission networks of Shelby County in Tennessee, USA. The examples show that the proposed framework and the selective RDA greatly improve efficiency of risk assessment of complex lifeline networks, which are characterized by a large number of components, complex network topology, and statistical dependence between component failures. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Seung Ho Baek Moonho Son Dongseon Kim Hyun-Woo Choi Young-Ok Kim 《Ocean Science Journal》2014,49(3):291-311
To assess the responses of planktonic organisms to pollutants in the coastal ecosystems of Gwangyang and Jinhae bays in Korea, we investigated seasonal changes in various biological factors during the period from 2010 to 2012. Based on the characteristics of nutrient uptake by planktonic organisms under the coastal pollution conditions, we focused on four major parameters: total phytoplankton, harmful algal bloom (HAB) species, heterotrophic bacteria (HB) and Escherichia coli to develop a planktonic index of biotic integrity (P-IBI). The threshold values for abundances of total phytoplankton, HAB species and HB were based on the zero Z-score following normal distribution of the data for each parameter during the three years. Based on this approach, the threshold values were: 1.2 × 106 cells L?1 for total phytoplankton; 3.3 × 104 cells L?1 for HAB species; and 1.7 × 106 cells mL?1for HB. Five grade levels for the P-IBI were established, based on the zero Z-scores. The threshold value for E. coli not to be normalized was based on the USEPA and the Korean Ministry of Oceans and Fisheries guidelines. Validity of the grades and threshold values for each parameter established using the field data were tested by algal bioassays in a mesocosm enclosure, which supported the threshold values obtained in the field. In Gwangyang Bay, the annual integrated score for the P-IBI in 2010 was better than in the other years of the study. In Jinhae Bay, the P-IBI for the inner area of Masan Bay was Grade IV–V, indicating unhealthy conditions relative to the central and western outer areas, where the P-IBI varied from Grade II to III. The P-IBI values for Gwangyang and Jinhae bays were mostly rated as “Good (Grade II) or Fair (Grade III)”, except for a few stations in the semi-enclosed areas of the inner part of Jinhae Bay. From an overall view based on the P-IBI developed in this study, the coastal ecosystem health status in Gwangyang Bay was in a better condition than Jinhae Bay. The P-IBI indicated also a change to an unhealthy status during the rainy periods of spring and summer, whereas during winter and autumn the index indicated healthy conditions. 相似文献
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Tintinnid species as biological indicators for monitoring intrusion of the warm oceanic waters into Korean coastal waters 总被引：2，自引：0，他引：2
Young-Ok Kim Kyoungsoon Shin Pung-Guk Jang Hyun-Woo Choi Jae-Hoon Noh Eun-Jin Yang Eung Kim Dongchull Jeon 《Ocean Science Journal》2012,47(3):161-172
This study examined seasonal and annual occurrences of warm oceanic tintinnid species in southern Korea coastal waters. The indicative species of tintinnids was monitored using three approaches: monitoring from cruises traveling from the warm pool in the western North Pacific to the Korea Strait; biweekly or monthly monitoring in the Korea Strait; and daily monitoring in the nearshore water. Annual pulses of warm oceanic indicator species were regularly observed in the Korea Strait. In September 2008 recorded a maximum species number of warm water indicators, a representative species for warm oceanic waters, Climacocylis scalaroides was simultaneously detected in the nearshore water as well as the Korea Strait. The result indicates that the greater warm water extension into Korean coastal areas was in September 2008. Sharp declines in species diversity were observed in the transitional area between neritic and Kuroshio zone in East China Sea (ECS). Epiplocyloides reticulata, reported previously as a Kuroshio indicator, was considered an ECS indicator species, as it was undetected in the western North Pacific central zone but was found abundantly in the ECS. Tintinnid species can be used as biological indicators to detect the inflow of warm oceanic waters into Korean coastal waters. 相似文献
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The spatiotemporal distributions of dissolved and/or dispersed oil in seawater and pore water were monitored on site by fluorometric detection method after the Hebei Spirit oil spill. The oil concentrations in intertidal seawater, 15 days after the spill, were as high as 16,600 μg/L and appeared to decrease below the Korean marine water quality standard of 10 μg/L at most sites 10 months after the spill. Fluorometric detection of oil in pore water was introduced to eliminate the effects of grain size for the quantification of oil in sediments and to better explain spatial and temporal distribution of oil pollution at sandy beaches. The fluorescence detection method was compared with the conventional laboratory technique of total petroleum hydrocarbon analysis using gas chromatography. The method of fluorescence detection of oil was capable of generating results much faster and more cost-effectively than the traditional GC technique. 相似文献
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Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method
in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes
in the ratio of3He to SF6 measured daily in the surface mixed layer. The measured gas exchange rate (k
CO
2), normalized to a Schmidt number of 600 for CO2 in fresh water at 20°C, was approximately 5.0 cm h-1 at a mean wind speed of 3.9 m s-1 during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed
previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river
and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed
(Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of
Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using222Rn and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using SF6 and3He. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measuredk
CO
2 value. 相似文献
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Yoon Tae-Ho Bae Jaeyong Kang Hye-Eun Choi Jung Hwa Lee Chung Il Park Won-gyu Kim Hyun-Woo 《Ocean Science Journal》2015,50(1):61-75
Ocean Science Journal - The molecular markers to distinguish different larval stages have various applications in ecological studies. Using the differential display RT-PCR technique, we isolated... 相似文献
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Park Jun-Seok Lee Chol-Young Park Jin-Soon Choi Hyun-Woo Ko Dong-Hui Lee Jung-Lyul 《Ocean Science Journal》2019,54(4):529-541
Ocean Science Journal - In this study, tidal stream energy resources of the Southwestern Sea of Korea were assessed using a numerical model, Modelo Hidrodinâmico (MOHID). This numerical model... 相似文献
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