• Journal of Information Technology Applications and Management
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• v.23 no.4
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• pp.25-39
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• 2016

Asset prices decline sharply and stock markets collapse when financial crisis happens. Recently we have encountered more frequent financial crises than ever. 1998 currency crisis and 2008 global financial crisis triggered academic researches on early warning systems that aim to detect the symptom of financial crisis in advance. This study proposes a risk recovery index for detection of good opportunities from financial market instability. We use SVM classifier algorithms to separate recovery period from unstable financial market data. Input variables are KOSPI index and V-KOSPI200 index. Our SVM algorithms show highly accurate forecasting results on testing data as well as training data. Risk recovery index is derived from our SVM-trained outputs. We develop a trading system that utilizes the suggested risk recovery index. The trading result records very high profit, that is, its annual return runs to 121%.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.127-133
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• 2009

The suspension bridge between Myodo and Gwangyang is located in the main navigation channel to Gwangyang Harbor. So, there is need for the collision protection against large vessels. In this paper, the method of risk analysis and non-linear numerical analysis are conducted to consider the ship collision effects. The results of risk analysis, the annual frequency of collapse is more than the acceptable frequency 0.0001. Therefore, as a ship collision protection, island protection with concrete block quay wall is planned. The ship collision force on the pylon is less than the lateral capacity of pylon from the nonlinear numerical analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5115-5122
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• 2013

This paper has studied about the development and application of landslide collapse prediction real-time monitoring system based on USN to detect and measure the collapse of landslide. The rainfall measuring sensor, gap water pressure sensor, indicator displacement measuring sensor, index inclination sensor, water content sensor and image analysis sensor are selected and these are applied on the test bed. Each sensor's operation and performance for reliability verification is tested by the instrument which is installed in the field. As the result, u-IT based real-time landslide monitoring system which is developed by this research for landslide collapse detection could minimize life and property damages because it makes advance evacuation with collapse risk pre-estimate through real-time monitoring on roadside cut and bedrock slopes. This system is based on the results of this study demonstrate the effect escarpment plan are spread throughout.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.165-171
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• 2009

We developed a 'multi-point vibration acceleration method' for accurately predicting the cavitation intensity in pumps. Pressure wave generated by cavitation bubble collapse propagates and causes pump vibration. We measured vibration accelerations at several points on a casing, suction and discharge pipes of centrifugal and mixed-flow pumps. The measured vibration accelerations scattered because the pressure wave damped differently between the bubble collapse location and each sensor. In a conventional method, experimental constants are proposed without evaluating pressure propagation paths, then, the scattered vibration accelerations cause the inaccurate cavitation intensity. In our method, we formulated damping rate, transmittance of the pressure wave, and energy conversion from the pressure wave to the vibration along assumed pressure propagation paths. In the formulation, we theoretically defined a 'pressure propagation coefficient,' which is a correlation coefficient between the vibration acceleration and the bubble collapse pressure. With the pressure propagation coefficient, we can predict the cavitation intensity without experimental constants as proposed in a conventional method. The prediction accuracy of cavitation intensity is improved based on a statistical analysis of the multi-point vibration accelerations. The predicted cavitation intensity was verified with the plastic deformation rate of an aluminum sheet in the cavitation erosion area of the impeller blade. The cavitation intensities were proportional to the measured plastic deformation rates for three kinds of pumps. This suggests that our method is effective for estimating the cavitation intensity in pumps. We can make a cavitation intensity map by conducting this method and varying the flow rate and the net positive suction head (NPSH). The map is useful for avoiding the operating conditions having high risk of cavitation erosion.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.47-53
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• 2017

The fundamental goal of this study is to minimize the uncertainty of the median fragility curve and to assess the structural vulnerability under earthquake excitation. Bayesian Inference with Markov Chain Monte Carlo (MCMC) simulation has been presented for efficient collapse response assessment of the independent intake water tower. The intake tower is significantly used as a diversion type of the hydropower station for maintaining power plant, reservoir and spillway tunnel. Therefore, the seismic fragility assessment of the intake tower is a pivotal component for estimating total system risk of the reservoir. In this investigation, an asymmetrical independent slender reinforced concrete structure is considered. The Bayesian Inference method provides the flexibility to integrate the prior information of collapse response data with the numerical analysis results. The preliminary information of risk data can be obtained from various sources like experiments, existing studies, and simplified linear dynamic analysis or nonlinear static analysis. The conventional lognormal model is used for plotting the fragility curve using the data from time history simulation and nonlinear static pushover analysis respectively. The Bayesian Inference approach is applied for integrating the data from both analyses with the help of MCMC simulation. The method achieves meaningful improvement of uncertainty associated with the fragility curve, and provides significant statistical and computational efficiency.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.1-12
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• 2021

Altman's Z-score is used to measure a company's financial health and to predict the probability that a company will collapse within 2 years. It is proven to be very accurate to forecast bankruptcy in a wide variety of contexts and markets. The goal of this study is to use Altman's Z-score model to forecast insolvency in non-financial publicly traded enterprises. Non-financial firms are a significant industry in Malaysia, and current trends of consolidation and long-term government subsidies make assessing the financial health of such businesses critical not just for the owners, but also for other stakeholders. The sample of this study includes 84 listed companies in the Kuala Lumpur Stock Exchange. Of the 84 companies, 52 are considered high risk, and 32 are considered low-risk companies. Secondary data for the analysis was gathered from chosen companies' financial reports. The findings of this study show that the Altman model may be used to forecast a company's financial collapse. It dispelled any reservations about the model's legitimacy and the utility of applying it to predict the likelihood of bankruptcy in a company. The findings of this study have significant consequences for investors, creditors, and corporate management. Portfolio managers may make better selections by not investing in companies that have proved to be in danger of failing if they understand the variables that contribute to corporate distress.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.374-382
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• 2020

Purpose: Recently, structural defects in old safety management facilities have led to the collapse of buildings and facilities. The purpose of this study is to develop guidelines for the installation of regular monitoring systems that determine the optimal sensor location for monitoring exhibition space building sensors equipped with visual elements in order to analyze the risk signs of exhibition space buildings and develop measurement technology. Method: The components, installation locations, alarm criteria, and management measures of the instrument are presented. Result: A measure was proposed to determine the location of sensors, secure signal processing technology for analysis by having unified visual perception, and configure optimal 'risk sign detection' based on sensor monitoring through test-bed operation. Conclusion: The results of this study can be prepared against the disasters that may arise from the collapse of exhibition buildings, and contribute to strengthening safety management capabilities.

• Earthquakes and Structures
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• v.5 no.4
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• pp.379-394
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• 2013

Post-earthquake fire (PEF) can lead to a rapid collapse of buildings damaged partially as a result of prior earthquake. Almost all standards and codes for the design of structures against earthquake ignore the risk of PEF, and thus buildings designed using those codes could be too weak when subjected to a fire after an earthquake. An investigation based on sequential analysis inspired by FEMA356 is performed here on the Immediate Occupancy, Life Safety and Collapse Prevention performance levels of structures, designed to the ACI 318-08 code, after they are subjected to an earthquake level with PGA of 0.35g. This investigation is followed by a fire analysis of the damaged structures, examining the time taken for the damaged structures to collapse. As a point of reference, a fire analysis is also performed for undamaged structures and before the occurrence of earthquake. The results indicate that the vulnerability of structures increases dramatically when a previously damaged structure is exposed to PEF. The results also show that the damaging effects of post-earthquake fire are exacerbated when initiated from the second and third floor. Whilst the investigation is made for a certain class of structures (conventional buildings, intermediate reinforced structure, 3 stories), the results confirm the need for the incorporation of post-earthquake fire into the process of analysis and design, and provides some quantitative measures on the level of associated effects.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.826-839
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• 2014

Fire is a continuous threat to FPSO topside modules as large amounts of oil and gas are passing through the modules. As a conventional measure to mitigate structural failure under fire, passive fire protection (PFP) coatings are widely used on main structural members. However, an excessive use of PFP coatings can cause considerable cost for material purchase, installation, inspection and maintenance. Long installation time can be a risk since the work should be done nearly at the last fabrication stage. Thus, the minimal use of PFP can be beneficial to the reduction of construction cost and the avoidance of schedule delay. This paper presents a few case studies on how different applications of PFP have influence on collapse time of a FPSO module structure. A series of heat analysis and thermal elasto-plastic FE analysis are performed for different PFP coatings and the resultant collapse time and the amount of PFP coatings are compared with each other.

• Smart Structures and Systems
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• v.22 no.4
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• pp.383-397
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• 2018

Traditional base isolation systems focus on isolating the seismic response of a structure in the horizontal direction. However, in regions where the vertical earthquake excitation is significant (such as near-fault region), a traditional base-isolated building exhibits a significant vertical vibration. To eliminate this shortcoming, a rocking-isolated system named Telescopic Column (TC) is proposed in this paper. Detailed rocking and isolation mechanism of the TC system is presented. The seismic performance of the TC is compared with the traditional elastomeric bearing (EB) and friction pendulum (FP) base-isolated systems. A 4-storey reinforced concrete moment-resisting frame (RC-MRF) is selected as the reference superstructure. The seismic response of the reference superstructure in terms of column axial forces, base shears, floor accelerations, inter-storey drift ratios (IDR) and collapse margin ratios (CMRs) are evaluated using OpenSees. The results of the nonlinear dynamic analysis subjected to multi-directional earthquake excitations show that the superstructure equipped with the newly proposed TC is more resilient and exhibits a superior response with higher margin of safety against collapse when compared with the same superstructure with the traditional base-isolation (BI) system.