• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1231-1240
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• 2019

Unlike land-based nuclear power plants, a marine or floating reactor is affected by external forces due to ocean conditions. These external forces can cause additional accelerations and affect each system and equipment of the marine reactor. Therefore, in designing a marine reactor and evaluating its performance and stability, a thermal hydraulic safety analysis code is necessary to consider the thermal hydrodynamic effects of ship motion. MARS, which is a reactor system analysis code, includes a dynamic motion model that can simulate the thermal-hydraulic phenomena under three-dimensional motion by calculating the body force term included in the momentum equation. In this study, it was verified that the dynamic motion model can simulate fluid motion with reasonable accuracy using conceptual problems. In addition, two modifications were made to the dynamic motion model; first, a user-supplied table to simulate a realistic ship motion was implemented, and second, the flow regime map determination algorithm was improved by calculating the volume inclination information at every time step if the dynamic motion model was activated. With these modifications, MARS could simulate the thermal-hydraulic phenomena under ocean motion more realistically.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.1-15
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• 2020

Nuclear power plants in South Korea are operated to cover the baseload demand. Hence they are operated at 100% rated power and do not deploy power tracking control except for startup, shutdown, or during transients. However, as the contribution of renewable energy in the energy mix increases, load follow operation may be needed to cover the imbalance between consumption and production due to the intermittent nature of electricity produced from the conversion of wind or solar energy. Load follow operation may be quite challenging since the operators need to control the axial power distribution and core reactivity while simultaneously conducting the power maneuvering. In this paper, a systems engineering approach for multi-physics load follow simulation of APR1400 is performed. RELAP5/SCDAPSIM/MOD3.4/3DKIN multi-physics package is selected to simulate the Korean Advanced Power Reactor, APR1400, under load follow operation to reflect the impact of feedback signals on the system safety parameters. Furthermore, the systems engineering approach is adopted to identify the requirements, functions, and physical architecture to provide a set of verification and validation activities that guide this project development by linking each requirement to a validation or verification test with predefined success criteria.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.455-465
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• 2021

The Molten Salt Reactor (MSR), one of the six advanced reactor types of the 4th generation nuclear energy systems, has many impressive features including economic advantages, inherent safety and nuclear non-proliferation. This paper introduces a system analysis code named TREND, which is developed and used for the steady and transient simulation of MSRs. The TREND code calculates the distributions of pressure, velocity and temperature of single-phase flows by solving the conservation equations of mass, momentum and energy, along with a fluid state equation. Heat structures coupled with the fluid dynamics model is sufficient to meet the demands of modeling MSR system-level thermal-hydraulics. The core power is based on the point reactor neutron kinetics model calculated by the typical Runge-Kutta method. An incremental PID controller is inserted to adjust the operation behaviors. The verification and validation of the TREND code have been carried out in two aspects: detailed code-to-code comparison with established thermal-hydraulic system codes such as RELAP5, and validation with the experimental data from MSRE and the CIET facility (the University of California, Berkeley's Compact Integral Effects Test facility).The results indicate that TREND can be used in analyzing the transient behaviors of MSRs and will be improved by validating with more experimental results with the support of SINAP.

• Journal of Korea Multimedia Society
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• v.24 no.7
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• pp.913-921
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• 2021

After arranging the general usability evaluation criteria of existing VUI researchers, this study verified how appropriate these criteria are for AI VUI specialized in navigation and the priority of their suitability. The VUI used in this study was analyzed through a survey from a total of 195 Chinese users after analyzing the navigation VUI used in China. As a result of the analysis, the usability evaluation criteria of the navigation VUI were extracted from three sub-factors of 'task accuracy', 'function satisfaction', and 'information reliability' in verifying conformance with general VUI evaluation criteria. With the recent advent of self-driving cars, safety and response speed are becoming very important, so Chinese users also ranked responsiveness as the top priority in VUI design, and the importance was also found to be high. Also, both men and women have the highest reactivity and the lowest multiplicity. VUI requires a convenient and natural interface to understand the intention between two objects through usability evaluation and verification in order to have effective interaction between humans and machines.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3768-3774
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• 2023

The purpose of the target system for the muon spin rotation, relaxation, and resonance (µSR) facility at the Rare isotope Accelerator complex for ON-line experiments (RAON) is to induce the production of a significant number of surface muons in thermally stable experiments. The manufactured target system was installed at RAON in the Sindong area near Daejeon in 2021. The design was made conservatively with a sufficient margin of safety through ANSYS calculations; however, verification experiments had to be performed on the ANSYS calculations. Because the 600-MeV proton beam has not yet been provided, an alternative way to reproduce the calculation conditions was required. The radio frequency (RF) heating method, which has not yet been applied to the target verification experiment but has several advantages, was used. It was observed that the RF heating method has promise for testing the thermal stability of the target, and whether the target system design process was performed conservatively enough was verified by comparing the RF heating experiments with the ANSYS calculations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.64-88
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• 2024

Security and reliability are the utmost importance facts in intelligent networked vehicles. Stochastic Petri Net and Z (SPZN) as an excellent formal verification tool for modeling concurrent systems, can effectively handles concurrent operations within a system, establishes relationships among components, and conducts verification and reasoning to ensure the system's safety and reliability in practical applications. However, the application of a system with numerous nodes to Petri Net often leads to the issue of state explosion. To tackle these challenges, a refinement and abstraction method based on SPZN is proposed in this paper. This approach can not only refine and abstract the Stochastic Petri Net but also establish a corresponding relationship with the Z language. In determining the implementation rate of transitions in Stochastic Petri Net, we employ the interval average and weighted average method, which significantly reduces the time and space complexity compared to alternative techniques and is suitable for expert systems at various levels. This reduction facilitates subsequent comprehensive system analysis and module analysis. Furthermore, by analyzing the properties of Markov Chain isomorphism in the case study, recommendations for minimizing system risks in the application of intelligent parking within the intelligent networked vehicle system can be put forward.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.85-94
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• 2024

As systems become more complex today, verifying the safety of complex systems is becoming increasingly important. However, validation activities using actual systems face limitations in terms of time and cost. To overcome these limitations, the functions, characteristics, and operations of physical assets can be implemented in a virtual environment similar to the real world, allowing for validation through simulations under various scenarios. By performing validation in a virtual environment, iterative tests can be conducted through simulations in a realistic virtual environment without physical models during the conceptual design phase. Tests can also be performed under malfunction conditions or extreme conditions. In this study, we introduce a verification method for railway vehicles in a virtual environment and propose a method of applying virtual verification from a life cycle perspective.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.696-703
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• 2015

This paper is a follow-up research of 'A study on the development of Safety Management Evaluation Index for Shipping Company'. It aims to develop the evaluation items of Safety Management Index(hereafter called as 'SMI') applicable to 'Safety Advantage Point', which is suggested as the sub-index of 'Safety Management Evaluation Index' function in the preceding research and also verify their adequacy. For that purpose, firstly, the 11 evaluation items were developed after collecting the practical opinions from safety management personnels in Korean shipping companies. Secondly, the survey was carried out for the verification of the adequacy of the 11 evaluation items. And lastly, its results was analysed, whether it has statistical meanings of differences in adequacy awareness amongst safety managers grouped depending on business type(coastal, ocean-going) and business capacity(number of owned-operating ships). As a result, there was no relevance between their adequacy awareness and business type of their companies. However, a difference in their adequacy awareness existed depending on their companies' business capacity(small, medium and large sized). In conclusion, when the safety management level of shipping companies is evaluated by SMI, the same indices can be applicable to both coastal and ocean-going shipping companies by a grouping of companies' business capacity.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.325-332
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• 2012

Due to its communication vulnerability resulting in a range of problems, e.g. eavesdropping, information exposure, traffic analysis and spoofing, RFID system becomes the target of attackers. Accordingly, many investigators have proposed various protocols to the extent of theorem proving or verification as the implementation is challenging. This paper thus proposes a safe RFID security protocol using public keys, session keys, hashes, XORs, and random numbers. Timestamps and hashes are applied to the most vulnerable section between readers and tags to detect attacks in attack signals with time difference. Also, to prevent tag information from being exposed in the last session, hash operation is adopted before communication. Finally, in this paper, we designed a RFID security protocol using public and session keys applicable to real systems and verified the security of the proposed protocol with a differentiated formal verification technique.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.126-136
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• 2014

In the Advanced Driver Assistance Systems (ADAS) of smart vehicle and Intelligent Transportation System (ITS) for to detect the boundary of lane is being studied a lot of Hough Transform. This method detects correctly recognition the lane. But recognition rate can fall due to detecting straight lines outside of the lane. In order to solve this problems, this paper proposed an algorithm to recognize the lane boundaries and the accumulator cells in Hough space. Based on proposed algorithm, we develop application for Android was developed by H/W verification. Users of smart phone devices could use lane detection and lane departure warning systems for driver's safety whenever and wherever. Software verification using the OpenCV showed efficiency recognition correct rate of 93.8% and hardware real-time verification for an application development in the Android phone showed recognition correct rate of 70%.