• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.25-38
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• 2023

Instrumentation and control systems measure and control various variables of nuclear facilities to operate nuclear power plants safely. A diverse protection system, a representative instrumentation and control system, generates a reactor trip and turbine trip signal by high pressure in a pressurizer and containment to satisfy the design requirements 10CFR50.62. Also, it generates an auxiliary feedwater actuation signal by low water levels in steam generators. Cybersecurity has become more critical as digital technology is gradually applied to solve problems such as performance degradation due to aging of analog equipment, increased maintenance costs, and product discontinuation. This paper analyzed possible cybersecurity threat scenarios in the diverse protection system using attack trees. Based on the analyzed cybersecurity threat scenario, we calculated the probability of attack occurrence and confirmed the cybersecurity risk in connection with the asset value.

• Journal of IKEEE
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• v.4 no.2 s.7
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• pp.266-273
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• 2000

A frequency model of an OCXO (Oven Controlled X-tal Oscillator) is suggested to implement a holdover algorithm in a DP-PLL (Digital Processing-Phase Locked Loop) system. This model is presented simply with second order polynomials with respect to temperature and aging of the OCXO. The model parameters are obtained from experimental data by applying the LSM (Least Squared Method). A holdover algorithm is also suggest using the frequency model. The obtained model is verified to simulate the holdover algorithm with experimental phase data due to variation of temperature.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.33-39
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• 2014

In this paper, a new on-chip aging sensing circuit based on flip-flops is proposed to detect a circuit failure of MOSFET digital circuits casued by aging phenomenon such as HCI and BTI. The proposed circuit uses timing windows to warn against a guardband violation of sequential circuits, and generates three warning bits right before circuit failures occur. The generated bits can apply to an adaptive self-tuning method for reliable system design as control signals. The aging sensor circuit has been implemented using 0.11um CMOS technology and evaluated by $4{\times}4$ multiplier with power gating structure.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2587-2589
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• 1999

In this paper, we propose a new control scheme for a PWM inverter using digital control. Digital control has various advantages in comparison with conventional analogue control. It can achieve high frequency switching of inverter and can be little influenced for temperature variations and aging of devices. This digitally-controlled PWM inverter is implemented using a Digital Signal Processor(DSPTMS320F240). The simulation results are given to verify the DSP based PWM inverter design and implementation.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1371-1378
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• 2023

Kiosks are gaining popularity as an essential tool that offers unmanned services and payment systems, and their use is rapidly increasing in the service industry. However, the use of kiosks can be challenging for the elderly who are not accustomed to digital technology and touchscreens. Consequently, this study develops an educational program that utilizes metaverse technology to enhance the digital skills and kiosk service accessibility of older adults. This research has created an educational system that allows the elderly to learn digital skills and kiosk access through play.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.213-221
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• 2002

In order to improve the reliability of XLPE cables, it is necessary to find the useful diagnostic parameter according to long term aging. This paper described the change of partial discharge(PD) phase Properties of XLPE cable insulation with branch type electrical tree degradation. for long term aging. To understand the PD Properties with $\phi$ -q-n distributed shape of XLPE insulation, specimens were prepared by 22.9㎸ distribution cable and made in a type of block(16${\times}$16${\times}$3[mm]). Ogura needles having tip radius of l0${\mu}{\textrm}{m}$ were inserted into each block pieces. The measuring system was consisted of PD detector, digitizer for digital conversion, VXI system for signal processing. The PD properties of the specimens were measured from initiation of tree to breakdown and their characteristics were analyzed. We analyzed the relationship between electrical properties(PD Quantity, PD initiation angle, PD extinction angle, PD occurrence angle : (PD extinction angle - PD initiation angle)) and the normalized aging rate. We found PD parameter, PD initiation angle and occurrence angle, which are a useful diagnostic parameter in estimating the branch type electrical tree for XLPE insulation condition.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1730-1737
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• 2004

The BI (Ball Indentation) method has the potential to assess the mechanical properties and to replace conventional fracture tests. In this study, the effect of aging on mechanical behavior of 1Cr-1Mo-0.25V steels procured by isothermal aging heat-treatment at four different aging times in the range of 0～1820 hours at 630$^{\circ}C$, were investigated using BI system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.13-18
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• 1998

After Computer-based PD measurement was referred in the 1970's, the new technology and a number of digital system have been studied. And the selection of PD patterns, extraction of relevant information for PD recognition are discussed because the number of pulse as a function of discharge magnitude and discharge pulse as a function of the power frequency cycl4e offer the information of the aging insulation. This paper investigates the discharge phase($\phi$) and magnitude(q), as well as the number of discharge(n) with regard to discharge signals generated in power cable. Therefore, according to properties analysis on the distribution of $\phi$ , q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.12
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• pp.1826-1831
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• 2022

Rapid Aging Society demands the transformation of medical paradigm of diagnosis and treatment towards prevention and management. This paper explores the norm and development of digital health care, focusing on Busan Metropolitan City. Digital health care which combines new ICT technology and medical technology is predictive, preventive, personalized and participatory; and suggests alternative to solve the problem of demographic changes and increasing social cost of medical welfare. Community Health Center in Busan is unique one based in the minimum community of collecting data from self-leading health management. Digital transformation using basic health data and social information can build preventive care system in the community. Easy access leads community center to test bed of developing new technology, as a living lab. In order to use the newly developed goods and service effectively, user-participatory test is nicessary. Finally community nurse and activists can specify health-welfare converged service through digital transformation empowerment training.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.727-729
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• 2017

According to the National Statistical Office and the Ministry of Health and Welfare Family Department, Korea has already estimated that the proportion of the elderly population aged 65 or over is estimated to be higher than the global average, and has already entered the "Aging Society". Moreover, it is estimated that the quality of life of the people improved by reaching the information society earlier than expected. However, unlike young people, elderly people show clear differences in access and use of information that is difficult to access new machines easily and cause intergenerational digital divide phenomenon. In order to solve such a phenomenon, we implemented a speech recognition based smart mirror system for elderly people. The installed system can provide lighting control, weather forecast and subway time information search service of the using voice recognition. Through the implemented system, it is expected that the elderly will have accessibility to new machines, information that gives a feeling of participating in the change of the new era will be obtained and the effect of living convenience will be expected.