• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1618-1625
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• 2015

The reliability of catenary system is very important for uninterrupted train operation as it supplies electric power to train without redundant facilities. This paper provides a systematic approach to the reliability analysis of the catenary system based on FMECA procedures defined by global standards such as MIL Std 1692a and IEC 60812. Field failure data collected from the operation and maintenance of high-speed railway catenary system for 9 years are used to derive critical failure modes and to evaluate the criticality of the failure modes. Evaluation of the criticality are carried out by quantitative procedures defined by MIL Std 1692a and by criticality matrix defined by IEC 60812. FMECA results suggests that three critical failure modes should be checked carefully during maintenance work, which include strand break of dropper and voltage equalizing wire, power supply failure of feeder. Maintenance procedure of catenary system in order of importance is suggested too. These results can be applied to maintenance planning and design of catenary system to improve the reliability of electric railway system.

• Journal of Wind Energy
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• v.13 no.3
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• pp.43-52
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• 2022

Although wind turbines have obtained type certification according to international standards and are released to the market, they cannot be regarded as design evaluations that consider site characteristics. Therefore, it is necessary to study the site-specific load analysis method based on the meteorological data measured at the candidate site. In this study, site-specific load calculation was performed based on the meteorological data from the Jeju Haengwon mast. Analysis results were compared and analyzed with the results calculated by IEC design Class (IIA). For the fatigue loads at the blade root and tower base, the site-specific condition was lower than the IEC IIA, but in the case of the ultimate load, the site-specific condition showed higher results in some design load cases (DLCs). Selecting a wind turbine suitable for a site through load evaluation considering site conditions can prevent the reduction of operation and maintenance (O&M) costs and the power loss caused by downtime. Finally, it is expected to contribute to the project's levelized cost of energy (LCOE) reduction.

• Fashion & Textile Research Journal
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• v.25 no.3
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• pp.398-408
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• 2023

Smart clothing products can experience a decrease in performance and reliability due to various mechanical, biological, and chemical stress factors that occur throughout their life cycle. These issues can hinder consumer acceptance of the products. This study aims to enhance the reliability of smart clothing and facilitate quality control by analyzing and identifying the current status of international standardization for smart clothing and electronic textiles (e-textiles). The focus of this analysis was on the durability test methods in the use environment. Furthermore, similar standards published by different standardization organizations for durability tests were compared in depth. The study showed that a total of 27 international standards have been developed or are currently under development. The current standardization efforts mainly aim to develop functionality and durability test methods for smart clothing and e-textile products. A detailed comparison was made between two international standards (IEC 63023-204-1:2023 and AATCC TM210:2019) specifically in relation to the washing durability test method and the electrical resistance measurement standards (BS EN 16812:2016 vs AATCC EP13-2021), before and after the environmental exposure tests. Based on this comparison, several suggestions have been made and discussed for the future revision of these international standards.

• Journal of Internet Computing and Services
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• v.13 no.1
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• pp.75-81
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• 2012

Previous RFID systems exclusively manage the tags and readers for each company in individual manner. Thus, RFID system manager should understand and design specifications such as tag events, data format, and etc, based on individual companies. But it is very difficult to know all statements. To resolve theses problems, there has been conceptual research about policy-based RFID service management model that is not restrained from standards of typical RFID systems, including EPCglobal standard, and ISO/IEC standard. However, previous proposed service management model only aimed event management without including device management. Therefore, in this paper, we propose extended device management policy model for giving shape to the proposed policy-based RFID service management model. If the proposing device management policy model is used for device management, we can integrate control management for heterogeneous middleware, diverse RFID devices, and applications for each company. Moreover, we show that the RFID device management policy is translated and processed as an example using the proposing policy model in real-time RFID system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1464-1471
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• 1999

A wide-band high power amplifier to use for radiated electromagnetic field immunity testing of EMS(Electromagnetic Susceptibility) standards has to meet IEC1000-4-3 specification in the frequency bandwidth of 80MHz to 1000MHz. The power amplifier to be described in this paper consists of driving and power stages with wide-band matched circuits by estimated impedances. The mismatching protection circuit is inserted in it to prevent from damage of power device when the output port of power amplifier is opened or shorted by user's mistake. The characteristics of the power amplifier are obtained output power over 100watts, gain over 40dB and flatness of $\pm$0.3dB in the frequency range of 80 ~300MHz. The harmonics suppression characteristics is measured over 20dBc. This wide-band high power amplifier can be useful fur radiated electromagnetic field immunity testing of IEC 1000-4-3 standard.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.9-17
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• 2006

Large steel industries have nonlinear loads such as electric arc furnaces. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time-varying harmonics. Harmonic simulations are performed to evaluate the harmonic voltage and current distortions throughout the system. This paper provides an in depth analysis on harmonics field measurement of the electric arc furnace loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519 and harmonic simulation for the time-varying harmonics. The EDSA program was used as a simulation tool for the case study.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.40-47
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• 2007

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time varying harmonics. Harmonic simulations are performed to evaluate the harmonic voltage and current distortions throughout the system. This paper provides an in depth analysis on harmonics field measurement of the high speed electric train loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519-l992, and harmonics simulation using EDSA program for the case study.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.363-370
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• 2012

Recently, International Maritime Organization has been developing e-navigation implementation strategy plan, which is focused on various services for vessel safety navigation. Then, different kinds of software will be developed in maritime area and with this, the quality issues are to be expected becoming more important. In this paper, we adopt software refactoring techniques to reduce the complexity of structure on source code level. It makes software program more effective to understand and modify, without any change of outward behavior. The existing AIS broadcast server program is used as an example for our trial, and calculating coupling and cohesion metric are introduced to analyze the refactoring effect, taking account of the maintainability of IEC/ISO9126 software quality standards.

• Journal of Information Technology Services
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• v.15 no.4
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• pp.63-72
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• 2016

Critical infrastructure has been operating in a closed environment with a completely separate information system and in the private area. However, with the current ICT environment changes due to convergence and open platforms it has increased the threats and risks to critical infrastructure. The importance of cyber security is increasing in the infrastructure control system, such as the outbreak of Ukraine blackout in 2015 by a malicious code called 'black energy'. This thesis aims to recognize the importance and necessity of protecting the critical infrastructure service, designing a security framework reflecting environmental and characteristic changes, and analyzing the management system suitable for a security framework. We also propose a theoretical basis for constructing a new security framework by comparing and analyzing seven international security management system standards, such as NIST 800-82 and IEC 62443-2-1, which are used in the control system. As a result, the environment surrounding critical infrastructure changes with the characteristics of connectivity, openness, and finality was studied, and as a response to this, many scholars and institutions present critical infrastructure security frameworks as cycle enhancement type structures, risk management structures, and management domain expansion structures. In response, the security framework encompassing these structures, CISF (Critical Infrastructure Security Framework), was designed. Additionally, through the security related international standard and criterion analysis, as a newly designed security standard suitable for CISF, IEC 62443-2-1 is reviewed and suggestions are made.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.533-538
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• 2018

As the use of digital radiographic system has been expanded, there are some concerns an increase about in patient of radiation dose. Therefore, International Electro-technical Commission (IEC) has been proposed a standard foe exposure index (EI). In this study, the EI was measured on human chest model using computed radiography (CR). Radiation quality used RQA5 of IEC62494-1. After acquiring the chest anterior posterior image (Chest AP) by using the phantom, the EI was obtained by applying the system response. In this study, we have analyzed the images with the detector size (Full filed ROI) and the optimized image (Fit filed ROI). The EI increased proportionally with radiation dose increase. Due to the discrete increase in pixel value, the EI showed an exponential increase. The discrete increase in noise equivalent quanta (NEQ) resulted in a discrete increase in the EI. The EI of the two images used in this study increased with increasing NEQ but showed different increments. For the measurement of the EI, IEC standards must be followed. The EI should be used as an index to evaluate the image quality for quality control of X-ray image rather than as an indicator of exposure dose. When calculating the EI, the system response should be applied depending on whether or not the grid is used. The size of the field should be obtained by including only the necessary parts.