• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.6079-6097
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• 2018

Safety-related systems (SRSs) has widely used in shipbuilding and power generation to prevent fatal accidents and to protect life and property. Thus, SRS performance is a high priority. The safety integrity level (SIL) is the relative performance level of an SRS with regard to its ability to operate reliably in a safe manner. In this article, we proposed an optimal design procedure to achieve the targeted SIL of SRSs. In addition, a more efficient failure mode and effects diagnostic analysis (FMEDA) process and optimization model were developed to improve cost efficiency. Based on previous IEC 61508 diagnostic analyses that revealed unnecessary costs associated with excessive reliability, the new approach consists of two phases: (i) SIL evaluation by FMEDA, and (ii) solution optimization for achieving the target SIL with minimal cost using integer-programming models. The proposed procedure meets the required safety level and minimizes system costs. A case study involving a gas-detection SRS was conducted to demonstrate the effectiveness of the new procedure.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.53-59
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• 2019

Continuous ship unloaders (CSUs) are used for the uninterrupted transport of material in processing industries, power plants, and harbors in accordance with the stream rate of the material. This study analyzed the structural integrity and fatigue life of a CSU structure using finite element structural analysis in ANSYS APDL software. The stress varied greatly depending on the luffing angle and the slew angle of the boom conveyor. The structural integrity of the CSU girder was evaluated by applying ASME BPVC Section VIII Division 2. The fatigue cycle at the angle with the greatest stress difference was calculated. The fatigue cycle was calculated by applying the JIS B 8821:2013 fatigue curve. It was confirmed that the fatigue cycle of the CSU satisfies the allowable fatigue of 200,000 cycles.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.11-18
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• 2019

Previous mutual authentication schemes operate on the basis of validated cryptographic functions and hash functions, but these functions require a certain amount of memory capacity. However, since ultra-lightweight IoT devices have a very small amount of memory capacity, these functions can not be applied. In this paper, we first propose a text steganography communication scheme suitable for ultra-lightweight IoT devices with limited resources, and then propose a mutual authentication scheme based on the text steganography communication. The proposed scheme performs mutual authentication and integrity verification using very small amount of memory. For evaluation, we implemented the proposed scheme on Arduino boards and confirmed that the proposed scheme performs well the mutual authentication and the integrity verification functions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.6
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• pp.1449-1461
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• 2024

As technology advances, processor speeds are increasing at a rapid pace and digital systems require a significant amount of data bandwidth. As a result, careful consideration of signal integrity is required to ensure reliable and high-speed data processing. Crosstalk has become a vital area of research in signal integrity for electronic packages, mainly because of the high level of integration. Analytic formulas were analyzed in this study to identify the features that can predict crosstalk in multi-conductor transmission lines. Through the analysis, five variables were found and obtained a dataset consisting of 302,500, data points. The study evaluated the performance of various regression models for optimization via automatic machine learning by comparing the machine learning predictions with the analytic solution. Extra tree regression consistently outperformed other algorithms, with coefficients of determination exceeding 0.9 and root mean square logarithmic errors below 0.35. The study also notes that different algorithms produced varied predictions for the two metrics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.760-770
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• 2012

In order to provide precision approach service based on GBAS, air navigation service providers should validate the GBAS system performance against international standard requirements and receive approval. The GBAS manufacturer should define integrity threat, analyze the integrity monitors and evaluate performance of the implemented monitors to verify integrity performance which is critical to the aircraft safety. This paper describes a statistical test result to evaluate performance of the code carrier divergence monitors implemented in KARI Integrity Monitor System software. The paper introduces analysis and test procedure which is developed for the performance evaluation and describes the analysis, the test scenario generation and the test results. The results show that the implemented monitors can detect the expected minimum detectable errors with satisfying the probability of missed detection requirements.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.257-264
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• 1998

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.389-389
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.112.1-112
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.493.2-493
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.213-213
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• 1998