• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.71-79
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• 2010

The simulator models for 500MW fossil power plant have been developed, and interconnected with the turbine control system to test and validate the digital instrumentation & control (I&C) systems before they are implemented in operating power plants. When the performance of a selected digital I&C system is tested, the corresponding simulator model is replaced by the plant digital I&C systems which is considered as a non-tunable system. The input/out variables of simulator models and control systems were mapped using the LabView in interface systems. This paper describes the interconnection method between the simulator model and the digital I&C system, and summarizes the validation test results performed at the condition of steady-state operation, normal evolution, and malfunction. The integrated validation method of digital I&C systems using the simulator models showed that the simulator can be used as a test bed for the implementation of digital I&C systems in power plants.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.165-178
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• 2013

A comprehensive review on the technical standards about human factors (HF) design and software reliability maintenance for digital instrumentation and control (I&C) and human-machine interface technology (HMIT) in Japanese light water reactor nuclear power plants (NPPs) was given in this paper mainly by introducing the relevant activities at the Japan Electric Association to set up many industrial standards within the traditional framework of nuclear safety regulation in Japan. In Japan, the Fukushima Daiichi accident that occurred on March 11, 2011 has great impact on nuclear regulation and nuclear industries where concerns by the general public about safety have heightened significantly. However for the part of HF design and software reliability maintenance of digital I&C and HMIT for NPP, the author believes that the past practice of Japanese activities with the related technical standards can be successfully inherited in the future, by reinforcing the technical preparedness for the prevention and mitigation against any types of severe accident occurrence.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.266-271
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• 2014

The Electromagnetic Interference(EMI) generating from corona discharge of transformer area can interference the digital Instrument and Control(I&C) systems located nearby transformers. When the potential gradient of the electric field around the conductor is high enough to form a conductive region but not high enough to cause electrical breakdown to nearby objects, the EMI of corona discharge emits with the conducted and radiated noise and it interferences the signals of the I&C systems. Since digital I&C systems have an efficiency and competitive price, the analog I&C systems have been upgraded and displaced with the digital I&C systems but which have less EMI Immunity. There was no assessment to I&C systems by EMI generating corona discharge nearby transformers. When the safety-related I&C systems are installed in plants, the verification of equipment EMI should be done not in site-specific test but in test facilities. There are the need to do the site-specific EMI evaluation of corona discharge nearby transformers. This paper assesses the margin between plant emission limits and the highest composite plant emission of corona. When the non safety-related I&C systems are placed in transformer area, it suggests the appropriate radiated susceptibility level to EMI of corona discharge.

• Journal of Applied Reliability
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• v.8 no.2
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• pp.101-111
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• 2008

Good diagnostics improves both the safety and system unavailability of digital safety systems. The measure of a diagnostic capability is called the Coverage Factor. Because the Failure Modes, Effects and Diagnostic Analysis (FMEDA) provides information on the failure rates and failure mode distributions necessary to calculate a diagnostic coverage factor for a component, the FMEDA can be used as a useful tool to calculate it. Through performing FMEDA on a digital signal processor (DSP) board used in a digital safety system, it is shown that some components of the DSP board can be replaced or improved to satisfy the required diagnostic coverage. That is, the FMEDA can serve as a useful verification tool to design a diagnostic capability for the DSP board.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.692-701
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• 2019

Recently, instrumentation and control (I&C) systems in nuclear power plants have undergone digitalization. Owing to the unique characteristics of digital I&C systems, the reliability analysis of digital systems has become an important element of probabilistic safety assessment (PSA). In a reliability analysis of digital systems, fault-tolerant techniques and their effectiveness must be considered. A fault injection experiment was performed on a safety-critical digital I&C system developed for nuclear power plants to evaluate the effectiveness of fault-tolerant techniques implemented in the target system. A software-implemented fault injection in which faults were injected into the memory area was used based on the assumption that all faults in the target system will be reflected in the faults in the memory. To reduce the number of required fault injection experiments, the memory assigned to the target software was analyzed. In addition, to observe the effect of the fault detection coverage of fault-tolerant techniques, a PSA model was developed. The analysis of the experimental result also can be used to identify weak points of fault-tolerant techniques for capability improvement of fault-tolerant techniques

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.471-482
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• 2012

To assess the risk of nuclear power plant operation and to determine the risk impact of digital systems, there is a need to quantitatively assess the reliability of the digital systems in a justifiable manner. The Probabilistic Risk Analysis (PRA) is a tool which can reveal shortcomings of the NPP design in general and PRA analysts have not had sufficient guiding principles in modelling particular digital components malfunctions. Currently digital I&C systems are mostly analyzed simply and conventionally in PRA, based on failure mode and effects analysis and fault tree modelling. More dynamic approaches are still in the trial stage and can be difficult to apply in full scale PRA-models. As basic events CPU failures, application software failures and common cause failures (CCF) between identical components are modelled.The primary goal is to model dependencies. However, it is not clear which failure modes or system parts CCF:s should be postulated for. A clear distinction can be made between the treatment of protection and control systems. There is a general consensus that protection systems shall be included in PRA, while control systems can be treated in a limited manner. OECD/NEA CSNI Working Group on Risk Assessment (WGRisk) has set up a task group, called DIGREL, to develop taxonomy of failure modes of digital components for the purposes of PRA. The taxonomy is aimed to be the basis of future modelling and quantification efforts. It will also help to define a structure for data collection and to review PRA studies.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.439-444
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• 2002

In this paper, we present both the link budget analysis according to system parameters and the cell coverage according to transmitter power and modulation scheme of digital MMDS among the wireless CATV system methods which is bated on the wireless internet service. Also, in this paper, we present C/I and number of subscriber according to splitting cell. In this paper, the cell coverage of which obtain the results according to both transmitter power from 0dBW to -9dBW and modulation scheme of QPSK, 16QAM and 64QAM based on link budget was analysis for system parameter of digital MMDS was able to provide from maximum 134km to minimum 4.3km. Also, in this paper, the number of subscriber of which obtain the results according to polarization wave, frequency of frequency reuse and C/I in 4. 6 and 8 sectors was able to provide from maximum 5,200DSI to minimum 1,300DSI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.6
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• pp.757-765
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• 2021

To carry out multi-domain operations included in the U.S. Department of Defense's national security strategy in 2018, timely data sharing between C4I systems is critical. Several studies of the Korean military have also raised the problems of interface and standardization between C4I systems, and it is necessary to establish a new plan to solve this problem. In this study, a solution to the problem was derived through case analysis that the U.S. Department of Defense has been pursuing for about 20 years to implement the data strategy after establishing the data strategy in 2003. and by establishing a data strategy suitable for the ROK military C4I system operating environment, developing a data model, selecting a standard for data sharing, and proposing a shared data development procedure, we intend to improve the data sharing capability between ROK military C4I systems.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2002.04a
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• pp.116-120
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• 2002

The purpose of study is to know how a tendency of organic design have become in mordern architecture-from 20C. architecture to current architecture. In particular, I want to find it out in digital architecture-one of current architecture. To do this, first, I research concept, categories, characteristics of organic design in mordern architecture. Second, I observe theoretical background and analyze design characteristics of digital architecture. Finally, I recognize form of digital architecture have a side of a tendency of organic design.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.217-226
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• 2011

As a diverse range of smartphones has been recently developed and diffused, the users of SNS (Social Network Service) also have been sharply increased. The SNS saves a variety of information such as exchanged pictures and videos, voice mails or location sharing, chat history, etc. as well as simple user data, so that the acquisition of data that are useful in the aspect of digital forensic is achievable. This thesis reviews the types of SNS that are available for the iPhone, a recent example of highly used smartphones, and types of data by each client. Also, efficient data analysis method for digital forensic investigations is suggested by analyzing the relationships within the collected data by each client.