• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.6
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• pp.711-718
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• 2019

BDD is a well-known alternative to the conventional Boolean logic method in fault tree analysis. As the size of fault tree increases, the calculation time and computer resources for BDD dramatically increase. A new failure path search and path restructure method is proposed for efficient calculation of CS and MCS from BDD. Failure path grouping and bottom-up path search is proved to be efficient in failure path search in BDD and path restructure is also proved to be used in order to reduce the number of CS comparisons for MCS extraction. With these newly proposed methods, the top event probability can be calculated using the probability by ASDMP(Approximate Sum of Disjoint MCS Products), which is shown to be equivalent to the result by the conventional MCUB(Minimal Cut Upper Bound) probability.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.923-930
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• 2006

In this paper we design the system test model for the weapon system embedded software based on the Time Factor Method(TFM) considering time factors and suggest the results through the case study. For doing this, we discuss the features, system tests and the object-oriented model based UML notations of the weapon system embedded software. And we give a test method considering time factors, a measuring method to time factors, and a test case selection algorithm as an approach to the TFM for designing the system test model. The TFM based system test model consists of three factors (X, Y, Z) in the weapon system embedded software. With this model, we can extract test cases through the selection algorithm for a maximum time path in 'X', identify the objects related to the Sequence Diagram in 'Y' and measure the execution time of each objects which is identified by the Timing Diagram in 'Z' Also, we present the method of extracting the system test cases by applying the proposed system test model to the 'Multi-function missile defense system'.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.24-30
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• 1993

When modeling a complex system we use an event tree to analyze propagation of failure. An event tree cannot represent the statistical interrelationships among parameters, but it can be represented as a statistically identical influence diagram so that parameter updating can be easily performed. After updating parameters we can calculate posterior distribution of the failure rate for each path. But exact distribution requires considerably complex numerical integration. We propose an approximation method to calculate the posterior and derive the predictive distribution of the time to next failure. Finally we introduce the system which implements our methodology.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.551-556
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• 2003

이산화탄소를 줄이기 위한 대책으로 국가 간 기후변화협약이 1992년 6월에 유엔환경개발회의에서 채택되었고 그 후속조치로 1997년 12월 교토에서 OECD 국가들에 대한 선진국 의무를 강화하는 교토의전서가 채택되기에 이르렀다. 국내의 의무부담 적용이 예상되는 2012년에는 국내 이산화탄소 예상 발생량 189백만 탄소톤 중 상당량의 탄소톤을 감축해야 할 것으로 추정된다.(중략)

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.661-665
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• 2003

기후변화협약 제3차 당사국총회(1997. 11)에서 채택된 교토의정서의 핵심은 온실가스(주로 이산화탄소)를 상품으로 거래할 수 있는 유연성 체계의 도입으로, 현재 기후변화협약에서는 지구환경 보호 그 자체에서 벗어나 자국의 경쟁력과 경제활동 보호를 위한 경제협약으로 발전되고 있으며, 선진기술 확보여부에 따라 협상의 우위가 좌우된다.(중략)

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.101-107
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• 2006

In this research, we propose a hybrid inference architecture for medical diagnosis based on dynamic knowledge map (DKM) and relational database (RDB). Conventional expert systems (ES) and developing tools of ES has some limitations such as, 1) time consumption to extend the knowledge base (KB), 2) difficulty to change the inference path, 3) inflexible use of inference functions and operators. To overcome these Limitations, we use DKM in extracting the complex relationships and causal rules from human expert and other knowledge resources. The DKM also can help the knowledge engineers to change the inference path rapidly and easily. Then, RDB and its management systems help us to transform the relationships from diagram to relational table.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3604-3613
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• 2022

The Physical Protection System (PPS) plays an important role and must effectively deal with various adversary attacks in nuclear security. In specific single adversary path scenarios, we can calculate the PPS effectiveness by EASI (Estimated Adversary Sequence Interruption) through Probability of Interruption (P_I) calculation. EASI uses a single value of the probability of detection (P_D) and the probability of alarm communications (P_C) in the PPS. In this study, we develop a multi-path analysis code based on EASI to evaluate the effectiveness of PPS. Our quantification method for P_I considers the variability and uncertainty of P_D and P_C value by Monte Carlo simulation. We converted the 2-D scheme of the nuclear facility into an Adversary Sequence Diagram (ASD). We used ASD to find the adversary path with the lowest probability of interruption as the most vulnerable paths (MVP). We examined a hypothetical facility (Hypothetical National Nuclear Research Facility - HNNRF) to confirm our code compared with EASI. The results show that implementing the variability extension can estimate the P_I value and its associated uncertainty. The multi-path analysis code allows the analyst to make it easier to assess PPS with more extensive facilities with more complex adversary paths. However, the variability of the P_D value in each protection element allows a significant decrease in the PI value. The possibility of this decrease needs to be an important concern for PPS designers to determine the P_D value correctly or set a higher standard for PPS performance that remains reliable.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.341-351
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• 2010

Alarm system is very important for the safety of nuclear power plant. When alarm, operator refers alarm logic diagrams to identify the logical relationship between the alarm and its causes. This paper propose a system which tracks the logical path between alarm and its causes on the alarm logic diagrams of Wolsung nuclear power plant unit 3 & 4. And a grammar for the validation of logic diagrams expressed in 2 dimensional strings, and logical operations with 3 states to track alarm-cause paths and to display the state of logics are proposed. This system is on operation at Wolsung site.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.74-80
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• 2006

This paper addresses the trajectory optimization of Unmanned Aerial Vehicles(UAVs) under multiple ground threats like enemy's anti-air radar sites. The power of radar signal reflected by the vehicle and the flight time are considered in the performance cost to be minimized. The bank angle is regarded as control input for a 1st-order lag vehicle, and input parameter optimization method based on Sequential Quadratic Programming (SQP) is used for trajectory optimization. The proposed path planning method provides more practical trajectories with enhanced survivability than those of Voronoi diagram method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.249-252
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• 2005

Recently, as the industrial demand for small quantity batch production of sheet metal components, the application of dieless forming technology to production of these component rise with the advantages of the reduction in manufacturing cost and time. In dieless forming processes, the determination of moving path of tool plays an important role in producing successfully formed parts. In order to obtain the optimized moving path of tool avoiding forming failure, it is necessary to examine the forming limit of sheet material. Therefore, in this study, as the new criterion to evaluate the formability of sheet material in dieless forming processes FDD(feeding depth diagram) with respect to feeding depth and punch diameter is proposed. Thus, the FDD for the sheet materials of STS304 and Ti-grade2 were obtained from a series of FDT(feeding depth test). In addition the possibility of the application of FLD in judging forming severity in dieless forming processes was investigated by comparing the results of FE analyses based on FLD and experimental FDT.