• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.151-164
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• 2013

A key input for the assessment of Human Error Probabilities (HEPs) with Human Reliability Analysis (HRA) methods is the evaluation of the factors influencing the human performance (often referred to as Performance Shaping Factors, PSFs). In general, the definition of these factors and the supporting guidance are such that their evaluation involves significant subjectivity. This affects the repeatability of HRA results as well as the collection of HRA data for model construction and verification. In this context, the present paper considers the TAsk COMplexity (TACOM) measure, developed by one of the authors to quantify the complexity of procedure-guided tasks (by the operating crew of nuclear power plants in emergency situations), and evaluates its use to represent (objectively and quantitatively) task complexity issues relevant to HRA methods. In particular, TACOM scores are calculated for five Human Failure Events (HFEs) for which empirical evidence on the HEPs (albeit with large uncertainty) and influencing factors are available - from the International HRA Empirical Study. The empirical evaluation has shown promising results. The TACOM score increases as the empirical HEP of the selected HFEs increases. Except for one case, TACOM scores are well distinguished if related to different difficulty categories (e.g., "easy" vs. "somewhat difficult"), while values corresponding to tasks within the same category are very close. Despite some important limitations related to the small number of HFEs investigated and the large uncertainty in their HEPs, this paper presents one of few attempts to empirically study the effect of a performance shaping factor on the human error probability. This type of study is important to enhance the empirical basis of HRA methods, to make sure that 1) the definitions of the PSFs cover the influences important for HRA (i.e., influencing the error probability), and 2) the quantitative relationships among PSFs and error probability are adequately represented.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.133-140
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• 2024

This study offers a comprehensive evaluation of the role and impact of advanced power semiconductors in solar module systems. Focusing on silicon carbide (SiC) and gallium nitride (GaN) materials, it highlights their superiority over traditional silicon in enhancing system efficiency and reliability. The research underscores the growing industry demand for high-performance semiconductors, driven by global sustainable energy goals. This shift is crucial for overcoming the limitations of conventional solar technology, paving the way for more efficient, economically viable, and environmentally sustainable solar energy solutions. The findings suggest significant potential for these advanced materials in shaping the future of solar power technology.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.744-747
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• 2005

The exploitable efficiency of UHP is very important in a projection system. We always use lens array for light shaping and energy distribution transformation in conventional projection system. Because of the limitation of arc gap and F/# of elements, the utilize efficiency is always dismal. In this paper we try to bring out a new method to reduce the sparkle formed on the PS converter and enhance the system efficiency.

• Korean Journal of Optics and Photonics
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• v.9 no.2
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• pp.104-110
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• 1998

The energy transfer between two incident beams in a photorefractive Cu-doped(0.04 wt. %) ${(K_{0.5}Na_{0.5})}_{0.2}{(Sr_{0.61}Ba_{0.39})}_{0.9}Nb_2O_6$ crystal is investigated at 632.8 nm laser wavelength. In addition, the coherent two-wave coupling properties of a photoinduced refractive-index grating in the presence of amplitude modulation on the signal beam or reference beam are also experimentally investigated. Some preliminary exprimental results are presented for use as a dynamic photorefracitive combiners and pulse shaping elements in coherent optical communication systems and in optical signal processing.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.737-744
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• 2012

EDM is the manufacturing process that uses the thermal energy to machine electrically conductive part. Despite a lot of research has been conducted for decades, the best aspect ratio of the micro hole using micro-EDM has not been over 30, yet. In the present study, new fabrication scheme was introduced to increase the aspect ratio of micro hole dramatically. Micro holes with less than 10 aspect ratio were aligned and welded together to manufacture a micro hole with extreme aspect ratio. Alignment of the micro hole with over 380 aspect ratio was conducted by the home-made apparatus installed with microscope and laser beam. The micro hole with extreme aspect ratio was used to shape pencil beam from proton beam generated from MC-50 cyclotron. The pencil beam was utilized to machine test specimen whose result was compared with GEANT4 computer simulation. It was shown that the experimental and simulation result were closer as the aspect ratio of the micro hole was bigger.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.16-24
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• 2021

A laser-engineered net shaping (LENS) process is a representative directed energy deposition process. Deposition characteristics of the LENS process are greatly dependent on the process parameters. The present paper preliminarily investigates deposition characteristics of Inconel 718 superalloy on S45C structural steel using a LENS process. The influence of process parameters, including the laser power and powder feed rate, on the characteristics of the bead formation and the dilution in the vicinity of the deposited region is examined through repeated experiments. A processing map and feasible deposition conditions are estimated from viewpoints of the aspect ratio, defect formation, and the dilution rate of the deposited bead. Finally, an appropriate deposition condition considering side angle, deposition ratio, and buy-to-fly (BTF) is predicted.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1180-1187
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• 2020

A team of operators is required for nuclear power plant operation, and communication between the operators is an important aspect of the team's ability to successfully carry out tasks. It has been difficult to evaluate the quality of this communication though, and as the relationship between communication quality and team performance has yet to be clarified, it has not been applied to most human reliability analysis (HRA) methodologies. This study investigates the relationship between the quality of communication and team performance using data from a full-scope training simulator of a digital main control room (MCR). Two important characteristics of communication were considered to determine quality: each operator's ability to self-confirm the status of a given task in a digital MCR, and the type of communication, as divided into 1-way, 2-way, and 3-way between operators. To measure team performance, the concept of an unsafe act was employed, which is defined as a human error that has the potential to negatively affect plant safety. Analysis results showed that the communication quality and team performance were related to each other. With this more clearly defined relationship, the results of this study can be applied to related performance shaping factors to improve HRA.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.114-120
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• 1991

In electron therapy, low melting point alloy is used for shaping of the field. Electron field shaping material affect the output factor as well as the collimator system. The output factors of electron beams for shaped fields from NELAC-1018 were measured using ionization chamber of Farmer type in water phantom. The output factors of electron beams depend on the incident energy, inherent collimator system and the size of shaped field. Obtained results were followings. 1. In the smaller applicator, output varied extremely according to extent of collimator opening. 2. The higher energy, the output is less varied according to treatment field at small field.

• KIISE Transactions on Computing Practices
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• v.23 no.2
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• pp.134-139
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• 2017

The existing screen mirroring systems are vulnerable to packet loss and inefficient for mobile devices with limited energy capacity. To overcome these problems, we propose a packet loss robust and energy efficient screen mirroring system for mobile device. The proposed system employs systematic Raptor codes for a forward error correction method to mitigate the video quality degradation that is caused by packet loss over wireless networks. For the mobile device energy saving, the proposed system shapes the screen mirroring traffic and adjusts the Raptor encoding parameters. In this paper, the proposed system is fully implemented on single board computers and is examined in a real Wi-Fi Direct network.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.98-103
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• 2004

Recently, a New Great Harbour Bridge between Mokpo City and Koha Island is planned to be built across Mokpo Inner Harbour, and Namak New Town is under construction adjacent to Mokpo. Citizels' concorn of and participation in 「Campaign for Shaping Mokpo into Beautiful Seaport」 are necessary to match the view of Mokpo harbour with natural scenery beautifully and with marine environment harmoniously. Citizens'ㄹ levels of consciousness of coastal and marine environment were ascertained through questionnaire surveys of local citizenry attitudes and opinions, and citizenry action plans for the conservation of coastal and marine environments around Mokpo harbour are suggested on the basis of the results of questionnaire surveys. Citizens' voluntary participations in local policy for the control of marine wastes production and in a campaign for the collections of marine debris and wastes around beaches and coastal areas are required. The operation of municipal sewage treatment plants is to be performed effectively and efficiently, and to be monitored and evaluated periodically by the general public, the local federation for environmental movement or NGO. The development and performance of marine environmental education programs and an enlightenment campaign for environment preservation are to be incessantly done in cooperation with local residents. Only when local government of Mokpo collects the public opinions and continues to shape Mokpo into international beautiful seaport in the direction of a reflex of public opinion, coastal and marine environment around Mokpo harbour can be kept in good condition with citizens' positive participation in citizenry long-term practical action plans for environment conservation.