• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.229-244
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• 2024

Recently, supply chain attacks against nuclear facilities such as "Evil PLC" are increasing due to the application of digital technology in nuclear power plants such as the APR1400 reactor. Nuclear supply chain security requires a asset management system that can systematically manage a large number of providers due to the nature of the industry. However, due to the nature of the control system, there is a problem of inconsistent management of attribute information due to the long lifecycle of software assets. In addition, due to the availability of the operational technology, the introduction of automated configuration management is insufficient, and limitations such as input errors exist. This study proposes a systematic asset management system using SBOM(Software Bill Of Materials) and an improvement for input errors using natural language processing techniques.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.363-374
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• 2015

Instrumentation and control(I&C) system has been mainly designed and operated based on analog technologies in existing Nuclear Power Plants(NPPs). However, As the development of Information Technology(IT), digital technologies are gradually being adopted in newly built NPPs. I&C System based on digital technologies has many advantages but it is vulnerable to cyber threat. For this reason, cyber threat adversely affects on safety and reliability of I&C system as well as the entire NPPs. Therefore, the software equipped to NPPs should be developed with cyber security attributes from the initiation phase of software development life cycle. Moreover through cyber security assessment, the degree of confidence concerning cyber security should be measured and if managerial, technical and operational work measures are implemented as intended should be reviewed in order to protect the I&C systems and information. Currently the overall cyber security program, including cyber security assessment, is not established on I&C systems. In this paper, we propose cyber security assessment methods in the Software Development Life Cycle by drawing cyber security activities and assessment items based on regulatory guides and standard technologies concerned with NPPs.

• Journal of the Korean Home Economics Association
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• v.50 no.7
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• pp.67-79
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• 2012

This study analyzed the characteristics of morphing in fashion design through the documentaries on morphing and fashion. The characteristics of morphing in fine art, media, and design area were categorized as reversible metamorphosis, sequential dissolve and blurring of interpolation boundaries. The results were as follow in fashion design. Reversible metamorphosis showed an automatic silhouette transformation by remote control, the metamorphosis of folding method by wearer's own movements and the automatic silhouette transformation by the air pressurizing method. It represented the thoughts of omnipotence as in the feeling of the magical world, the human desire for control in life, the rationalization of magical thinking and imaginative power, the creation of a new dress space and the extension of dress function. Sequential dissolve showed juxtaposition in the same area by the time order, juxtaposition in virtual space through the computer graphics, the series of fashion photography by steel cut of the dress making process and the blending of digital film and fashion design. It represented the approach for the storytelling of fashion show, implication of creative fashion design process and the creation of organic forms and the feeling of fantasy through artificial technology. The blurring of interpolation boundary showed an overlay of different fabrics with transparent boundaries, an overlay of different patterns with transparent boundaries and the blending of fabrics through the visual mixing of color. It represented the obfuscation of the object, the connotation of the space order, the connotation of the extensive and various meanings and the integrative property of objects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.732-737
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• 2005

Distal 3D Real Object Duplication System(RODS) consists of 3D Scanner and Solid Freeform Fabrication System(SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and a industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer(SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. Also, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Multi-Laser Sintering(SMLS) process and 3-axis dynamic Focusing Scanner for scanning large area instead of the existing $f\theta$ lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, scan spacing. Now, this study is in progress to eveluate the effect of experimental parameters on the sintering process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4171-4176
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• 2012

The conventional block systems for railway signaling currently in operation in Korea have not been electrified or integrated and therefore there have been difficulties in terms of construction and maintenance. Two independent systems have been installed for ABS and LEU of ATP system (for speeded-up lines), although they deal with the same signaling information at the same location in order to control the trains. In these conventional ABS and LEU, a number of duplicate modules are installed in each device including lamp detection units and power supply units and it results increased manufacturing costs and maintenance efforts. This paper deals with the prototype development of integrated electronic block system with CPU-based digital control methods in order to overcome the limitations of the conventional ABS. The suggested system is the integration of the conventional ABS with LEU of ATP and it is also applicable for the non-ATP sections as well.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.344-347
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• 2011

This paper presents qualification process of the T700/701K turbo-shaft engine for Korean Utility Helicopter(KUH). The T700/701K is the rear-drive variant of the GE's T700-701C/D engine which was qualified for military applications in the world. The main scope of the development is the modification from a front-drive engine to a rear-drive one, the performance enhancement of the power turbine and the incorporation of two channel FADEC(Full Authority Digital Engine Control) system for more reliable operation. Therefore, T700/701K engine must be qualified by Korean government in order to perform a flight in the country. Reflecting the influence of developing scope, the main requirements including performance and control are verified by test and analysis, while the requirement for module or component that is same to that of T700-701C/D are verified by similarity.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.292-299
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• 2013

In this paper, we developed a data transmission system over coaxial cable based on the IEEE 802.15.3 MAC and Ultra-Wideband(UWB) Physical Layer. This system is capable of operation in both wireless and wired medias. When operating on coax cable it is capable of Gigabit bi-directional data rate operation on in-home coax wiring and over Hybrid-Fiber-Coax(HFC) cable infrastructure. The developed system transceives command, control and data over a 75 ohm coax system in a home or office. This system operates at a center frequency of 4GHz with a total occupied bandwidth of 1.33Ghz centered on 4GHz. The system uses BPSK modulation and sends symbols at a maximum power level of +15dBm. It has been tested and works through up to three CATV RF splitters in a home environment.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.190-193
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• 2001

In order to verify the efficiency or availability and stability of photovoltaic(PV) generation systems, huge system apparatuses are needed, in general, in which an actual size of solar panel, a type of converter system and some amount of load facilities should be installed in a particular location. It is also hardly possible to compare a Maximum Power Point Tracking (MPPT) control scheme with others under the same weather and load conditions in an actual PV generation system. The only and a possible way to bring above-mentioned problem to be solved is to realize a transient simulation scheme for PV generation systems using real weather conditions such as insolation and surface temperature of solar cell. The authors, in this paper, introduces a novel simulation method, which is based on a real-time digital simulator (RTDS), for PV generation systems under the real weather conditions. Firstly, VI characteristic equation of a solar cell is developed as an empirical formula and reconstructed in the RTDS system, then the real data of weather conditions are interfaced to the analogue inputs of the RTDS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme in this paper. The results shows that the cost effective verifying for the efficiency or availability and stability of PV generation systems and the comparison research of various control schemes like MPPT under the same real weather conditions are possible.

• Nuclear Engineering and Technology
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• v.24 no.3
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• pp.285-296
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• 1992

The conceptual design of the Plant Operations Regulator (POR) is presented for the pressurized water reactor plants. The POR is a digital supervisory limitation control system The POR assures that the plant does not exceed the operating limits by regulating the plant operations through monitoring the operating margins of the critical parameters. The POR is aimed at increasing the operating flexibility which allows the nuclear plant to meet the grid demand in very efficient manner. It responds to the grid demand without penalizing plant availability by limiting the load demand or by modifying the plant control schemes when the operating limits are approached or violated. The POR design concepts were tested using simulation responses of the 1000 MWe pressurized water reactors, Yonggwang Units 3 & 4. The simulation results illustrate that the POR can be used to improve operating flexibility.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.151-155
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• 2016

In this paper, we present the LED dimming control system by using ADPCM (Adaptive Differential Pulse Code Modulation). This ADPCM apparatus accurately controls the LED current with high resolution reducing the RFI (radio frequency interference) due to the spreading out of the harmonics of current of pulses. Additionally, this makes it easier to increase the accuracy of control operation. This study introduces to make a digitally controlled circuit for controlling LED with high-energy efficient by adopting pulse current to LED. The LED current drive system we designed are two systems, the digitally-controlled unit and analog switching mode power supply unit, can be developed separately. The simulation shows the sigma delta modulation of digital to analog converter's output when the input level is 0.7. From this simulation, the output is approached to accurately 0.15% to target value with 510 pulses.