• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.125-129
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• 2007

In this paper, a PMS(Pavement Management System) application is presented to control the LCC(Life Cycle Cost) of road pavement. The aim of this paper is to provide the decision makers with the planning information regarding maintenance strategies for efficient road pavement management. The validity of PMS application presented in this paper is investigated through case studies for conducted for 22 national highway road sections in Korea.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.52-52
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• 2017

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.145-153
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• 2011

In the system necessary for safety such as the train control system, to make train control information be sent correctly is very important to enable organic movement between trains. In the case of the system such as RF-CBTC (Radio Frequency Communication Based Train Control) the control related information is sent through wireless transmission between on-board system of a train and wayside transmitter. The wayside transmitter collects the running information such as location, velocity from the on-board system and operates the optimizing control by sending the control information such as the target, limited velocity to the on-board system. But, when the communication disconnect or train failure, the critical hazard such as train collision or derailment may be possible because the RF-CBTC depends on the information through wireless communication. This paper discribes of performing Fall-Back system to detect train position in the case of rail break or communication failure to avoid train accident and allows train to be operated safely. It can be implemented with ATP function through track circuits using active-type transformers and axle counters, and allows train to be operated manually in emergency status.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.5
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• pp.345-353
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• 2015

There are many software reliability models that are based on the times of occurrences of errors in the debugging of software. It is shown that it is possible to do parameter inference for software reliability models based on finite failure model and non-homogeneous Poisson Processes (NHPP). For someone making a decision to market software, the conditional failure rate is an important variables. In this case, finite failure model are used in a wide variety of practical situations. Their use in characterization problems, detection of outlier, linear estimation, study of system reliability, life-testing, survival analysis, data compression and many other fields can be seen from the many study. Statistical process control (SPC) can monitor the forecasting of software failure and thereby contribute significantly to the improvement of software reliability. Control charts are widely used for software process control in the software industry. In this paper, proposed a control mechanism based on NHPP using mean value function of polynomial hazard function.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.2
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• pp.35-54
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• 2009

The recent economic crisis not only reduces the profit of department stores but also incurs the significance losses caused by the increasing late-payment rate of credit cards. Under this pressure, the scope of credit prediction needs to be broadened from the simple prediction of whether this customer has a good credit or not to the accurate prediction of how much profit can be gained from this customer. This study classifies the delinquent customers of credit card in a Korean department store into homogeneous clusters. Using this information, this study analyzes the repayment patterns for each cluster and develops the credit prediction system to manage the delinquent customers. The model presented by this study uses Kohonen network, which is one of artificial neural networks of data mining technique, to cluster the credit delinquent customers into clusters. Cox proportional hazard model is also used, which is one of survival analysis used in medical statistics, to analyze the repayment patterns of the delinquent customers in each cluster. The presented model estimates the repayment period of delinquent customers for each cluster and introduces the influencing variables on the repayment pattern prediction. Although there are some differences among clusters, the variables about the purchasing frequency in a month and the average number of installment repayment are the most predictive variables for the repayment pattern. The accuracy of the presented system leaches 97.5%.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.4 s.7
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• pp.117-122
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• 2002

A large number of accidents at an underground place have been happening, including the gas explosion under construction of subway, the fires of underground utility and underground shopping malls, and other explosion, at home and abroad recently. These accidents make the function of a city ineffective due to the paralyses of electricity and communications net as well as the loss of property, and cause people to feel unsecured with accompaniment of a heavy of toll of lives. This study suggests safety assessment items and fire protection assessment technique for underground shopping malls by extracting dangerous elements in the management stage through examination of related accidents, documents and present conditions.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.152-155
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• 2007

Efficiency and limitations of HAZUS-MH, a GIS based systematic and informative system developed by FEMA and NIBS for natural hazard loss estimations, are discussed by means of a pilot study in the Korean Peninsular. Gyeongsang-do has been selected for the test after careful reviews of previous studies including historical and modern seismicity in the peninsular. A ShakeMap for the selected scenario earthquake with magnitude 6.7 in Gyeongju area is prepared. Then, any losses due to the scenario event have been estimated using HAZUS. Results of the pilot test show that the study area may experience significant physical, economic and social damages. Detailed study in the future will provide efficient and crucial information to the decision makers and emergency agents to mitigate any disaster posed by natural hazards.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.55-61
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• 2004

Rapid developments in sensor technologies now allow the generation of multi-source topographical data. For many applications, however, the geospatial information provided by individual sensors is not complete, precise, and consistent. To solve these inherent problems, additional diverse sources of complementary data can be used and fused. In this paper, the experiment was done for generation of 3D orthoimage data using LIDAR data and digital camera image. And the results show that 3D orthoimage can be used for the flood monitoring.

• Structural Engineering and Mechanics
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• v.66 no.4
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• pp.515-529
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• 2018

Multiple hazards (multihazard) conditions may cause significant risk to structures that are originally designed for individual hazard scenarios. Such a multihazard condition arises when an earthquake strikes to a bridge pre-exposed to scour at foundations due to flood events. This study estimates the impact spectrum of flood-induced scour on seismic vulnerability of bridges. Characteristic river-crossing highway bridges are formed based on the information obtained from bridge inventories. These bridges are analyzed under earthquake-only and the abovementioned multihazard conditions, and bridge fragility curves are developed at component and system levels. Research outcome shows that bridges having pile shafts as foundation elements are protected from any additional seismic vulnerability due to the presence of scour. However, occurrence of floods can increase seismic fragility of bridges at lower damage states due to the adverse impact of scour on bridge components at superstructure level. These findings facilitate bridge design under the stated multihazard condition.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.131-137
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• 2005

In this paper, we propose a Bayesian approach to determine the adaptive preventive maintenance(PM) policy for a general sequential imperfect PM model proposed by Lin, Zuo and Yam(2000) that PM not only reduces the effective age of the system but also changes the hazard rate function. Assuming that the failure times follow Weibull distribution, we adopt a Bayesian approach to update unknown parameters and determine the Bayesian optimal sequential PM policies. Finally, numerical examples of the optimal adaptive PM policy are presented for illustrative purposes.