• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4039-4047
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• 2023

This contribution describes the application of HPGe detector for the airborne quantitative analysis. The hardware of the airborne HPGe system was designed from the commercial components with only exception of the newly designed AirHPGeSpec special software to control, measure and process the data. The system was calibrated for the local air kerma rates measured on helicopter board and its conversion to the air kerma rates at 1 m above the ground was proposed. Two examples of the air kerma rates measured over the former uranium mining areas are presented and compared with the results of other airborne system on the board. This airborne HPGe system could be also used for measuring the surface activities in a radiation event. The nuclides of ¹³¹I, ¹³²Te - ¹³²I, ¹³³I, ¹³⁴I, ¹³⁵I, ¹³⁷Cs, ¹³⁴Cs, ⁸⁸Rb and ¹⁰³Ru were selected from possible nuclear power plant emergency scenarios. The Monte Carlo simulation was used to calculate HPGe detector efficiencies for the flight altitudes from 25 to 300 m for the energies from 300 keV to 3 MeV of the nuclides in question. Also, the detection limits according to the Currie method as well as ISO 11929-2010 for selected nuclides are presented.

• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.2923-2936
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• 2024

Modern risk management philosophy emphasizes the invulnerability of human beings to cope with all kinds of emergencies. The Nuclear Accidents Emergency Response Organization (NAERO) of Nuclear Power Plant (NPP) is the primary body responsible for nuclear accidents emergency response. The invulnerability of the organization to disturbance or attack from internal and external sources is crucial in the completion of its response missions, reduction of severity of accidents, and assurance of public and environmental safety. This paper focused on the NAERO of a certain NPP in China, and applied the complex network theory to construct the network model of the organization. The topological characteristics of the network were analyzed. Four importance evaluation indexes of network nodes including Degree Centrality (DC), Betweeness Centrality (BC), Closeness Centrality (CC) and Eigenvector Centrality (EC), along with Pearson coefficient correlation among the indexes were calculated and analyzed. Size of the Largest Connected Component (LCC) and Network Efficiency were used as measures regarding the invulnerability of the network. Simulation experiments were conducted to assess the invulnerability of network against various attack strategies. These experiments were conducted both in the absence of node protection measures and under protection measures with different node protection rates. This study evaluated the invulnerability of the NAERO network, and provided significant decision-making basis for the enhancement of the network's invulnerability.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.825-830
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• 2012

Radiation and its various industrial applications have been growing at approximately 10 percent per year for the past decade in Korea. As a result, the importance of the Education and Training (E&T) in radiation protection is of upmost importance. This paper is intended to investigate the present status of the E&T on radiation protection and safety in Korea and to draw up the improvements of the E&T courses required for building the national radiation safety infrastructure. For these purposes, the E&T data from the six major domestic organizations providing radiation protection training courses were investigated and analyzed. Each of the organizations is offering several kinds of E&T courses based on their own specific functions. These organizations have administrative facilities equipped with the latest technology for E&T in radiation protection. The E&T courses mainly cover the training courses for radiation workers, radiological emergency staff, license applicants, license holders, and regulatory staff. In 2010, a total of 58 E&T courses were carried out across six organizations. The conclusions make a number of observations highlighting challenges such as: establishing a formal feedback mechanism, introducing more practical training sessions, developing training courses tailored to the job categories and target audiences, and designing education and training courses in radiation protection that comply with current obligations as well as future requirements.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.910-920
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• 2008

In Korea, more than 70% of the territory consists of mountains. Therefore, the construction of roads and railways has generally involved with a steep rock slope in which the event of rockfalls are often occurred due to the weathered rock conditions and rainfalls etc. This is dangerous when the rock falls into the road and railway on which vehicles and trains are running. In order to prevent such rockfalls, the rockfall protection fence consisting of post, wire rope, and PVC coating steel net has most used at the bottom of rock slopes. In a general practice, an absorbing rockfall energy, 50kJ is specified by the Ministry of Construction and Transportation. However, questions still remain about whether the rockfall protection fence works effectively or not. In this study, a typical wire rope used in the standard rockfall protection fence was replaced by the high carbon steel wire rod and to validate its capacity of rockfall energy absorbing the field rockfall tests were conducted. The testing results show that a new rockfall protection fence using the high carbon steel wire rods can absorb the rockfall energy more than 50kJ and 20% of construction cost was saved in comparison with the previous rockfall protection fence.

• Journal of Information Processing Systems
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• v.20 no.2
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• pp.149-158
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• 2024

Traditional manual identification of crop leaf diseases is challenging. Owing to the limitations in manpower and resources, it is challenging to explore crop diseases on a large scale. The emergence of artificial intelligence technologies, particularly the extensive application of deep learning technologies, is expected to overcome these challenges and greatly improve the accuracy and efficiency of crop disease identification. Crop leaf disease identification models have been designed and trained using large-scale training data, enabling them to predict different categories of diseases from unlabeled crop leaves. However, these models, which possess strong feature representation capabilities, require substantial training data, and there is often a shortage of such datasets in practical farming scenarios. To address this issue and improve the feature learning abilities of models, this study proposes a deep transfer learning adaptation strategy. The novel proposed method aims to transfer the weights and parameters from pre-trained models in similar large-scale training datasets, such as ImageNet. ImageNet pre-trained weights are adopted and fine-tuned with the features of crop leaf diseases to improve prediction ability. In this study, we collected 16,060 crop leaf disease images, spanning 12 categories, for training. The experimental results demonstrate that an impressive accuracy of 98% is achieved using the proposed method on the transferred ResNet-50 model, thereby confirming the effectiveness of our transfer learning approach.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2276-2282
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• 2023

We deploy artificial neural networks to unfold neutron spectra from measured energy-integrated quantities. These neutron spectra represent an important parameter allowing to compute the absorbed dose and the kerma to serve radiation protection in addition to nuclear safety. The built architectures are inspired from convolutional neural networks. The first architecture is made up of residual transposed convolution's blocks while the second is a modified version of the U-net architecture. A large and balanced dataset is simulated following "realistic" physical constraints to train the architectures in an efficient way. Results show a high accuracy prediction of neutron spectra ranging from thermal up to fast spectrum. The dataset processing, the attention paid to performances' metrics and the hyper-optimization are behind the architectures' robustness.

• The Korean Journal of Ecology
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• v.23 no.3
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• pp.201-209
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• 2000

The flora, distribution area, vegetation structure, annual net primary production, and nutrient uptake of the vascular hydrophytes, hygrophytes and mesophytes were investigated in the wetlands of the Asan-Lake, Chungchongnam-do and Kyonggi-do, Korea from March to October in 1997 to reveal the correlation between the plant community and the lake environment. The flora was composed of 38 families, 89 genera, 106 species, 14 varieties or total 120 kinds of the vascular plants. The life from of the hydrophytes were classified as 14 kinds of emergent plants, 5 kinds of submerged plants, and 4 kinds of free-floating plants, respectively. The number of species was various to 4 ∼85 kinds in each site. The dominant species was Zizania latifolia, and the importance values of Zizania latifolia, Typha orientalis, Phragmites communis, and Spirodela polyrhiza were 39.58, 14.90, 13.97, and 7.64, respectively. The distribution area of the emergent hydrophytes, hygrophytes, and mesophytes was 49.3 ㏊ (90.5%), and free-floating plants was 5.2 ㏊ (9.5%), whereas the floating-leaved and submersed plants were rare. Annual net production of the emergent hydrophytes, hygrophytes, and mesophytes was 547.9 ton D.W./yr (98%), and those of the free-floating plants was 10.5 ton D.W./yr (2%), and 558.4 ton D.W./yr in the whole lake ecosystem. The total uptake of nitrogen and phosphorus by the vascular plants was 7,099 and 1,891 ㎏/yr in the whole lake ecosystem.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3608-3615
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• 2024

This study introduces a lead-free alternative for enhanced radiation protection. While lead aprons effectively attenuate ionizing radiation, concerns regarding flexibility, weight, and environmental hazards persist. In response, the present research is focused on producing an innovative sheet shielding comprised of carefully selected dense metal oxide microparticles (DMOs-MPs) and liquid silicone rubber (LSR). To evaluate the efficacy of the LSR samples, the current study uses rigorous testing procedures, such as microstructure characterization using EDX and FESEM. Furthermore, the study investigated key attenuation parameters within the LSR samples. Radiation protection was greatly and effectively supplied using DMOs-MPs filler (Bi-1 to Bi-7) in LSR samples; this protection reached 99.9% in the X-ray energy range. Due to the unique characteristics of the Bi-7, the results demonstrated that the samples' shielding efficiency improved with the addition of high atomic number and high-density fillers. It had the greatest attenuation coefficient and density. At 60 keV, Bi-7's density was 2.980 gcm^-3, and its LAC and MAC were 19.2621 cm^-1 and 6.4638 cm²/g, respectively. It also had the lowest half-value layer values in the energy range of 60-120 keV. The LSR samples showed effective radiation absorption for different energy levels, indicating that LSR can enhance the flexibility and comfort of the apron while providing adequate radiation protection. The incorporation of the DMOs-MPs with LSR represents an effective contribution and a noteworthy stride to enhance the safety and well-being of medical professionals routinely exposed to ionizing radiation.

• Nuclear Engineering and Technology
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• v.46 no.4
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• pp.461-466
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• 2014

Security of radioactive sources has been an issue since the earliest days of safety regulation of such materials. Since the events of September 11 2001, some governments and regulatory bodies have been much more focussed on these issues and have introduced extensive and enhanced security arrangements. International organisations like the IAEA and WINS have worked hard to help States in this regard. However, only a minority of States have implemented statutory security systems for radioactive source security. Why have so many States still to take action? What can be done to encourage and support these changes? This paper will offer some possible explanations for the lack of action in so many States and some potential answers to these questions.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4693-4697
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• 2022

Parylene coating was adopted on CdZnTe (CZT) detector as a mechanical protection layer after wet passivation with hydrogen peroxide (H₂O₂) and ammonium fluoride (NH₄F). Wet chemical passivant lose their effectiveness when exposed to the ambient conditions for a long time. Parylene coating could protect the effectiveness of passivation, by mechanically blocking the exposure to the ambient conditions. Stability of CZT detector was tested with the measurement of leakage current density and response to radio-isotopes. When the enough thickness of parylene (>100 ㎛) is adopted, parylene is a promising protection layer thereby ensuring the performance and long-term stability of CZT detectors.