• Nuclear Engineering and Technology
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• 제39권3호
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• pp.221-230
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• 2007

Wavelet theory was applied to detect a singularity in a reactor power signal. Compared to Fourier transform, wavelet transform has localization properties in space and frequency. Therefore, using wavelet transform after de-noising, singular points can easily be found. To test this theory, reactor power signals were generated using the HANARO(a Korean multi-purpose research reactor) dynamics model consisting of 39 nonlinear differential equations contaminated with Gaussian noise. Wavelet transform decomposition and de-noising procedures were applied to these signals. It was possible to detect singular events such as a sudden reactivity change and abrupt intrinsic property changes. Thus, this method could be profitably utilized in a real-time system for automatic event recognition(e.g., reactor condition monitoring).

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.285-294
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• 2023

Autonomous radiation source detection has long been studied for radiation emergencies. Compared to conventional data-driven or path planning methods, deep reinforcement learning shows a strong capacity in source detection while still lacking the generalized ability to the geometry in unknown environments. In this work, the detection task is decomposed into two subtasks: exploration and localization. A hierarchical control policy (HC) is proposed to perform the subtasks at different stages. The low-level controller learns how to execute the individual subtasks by deep reinforcement learning, and the high-level controller determines which subtasks should be executed at the current stage. In experimental tests under different geometrical conditions, HC achieves the best performance among the autonomous decision policies. The robustness and generalized ability of the hierarchy have been demonstrated.

• 대한핵의학회지
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• 제33권3호
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• pp.262-272
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• 1999

목적: 후두엽 간질에서 발작간기 F-18-FDG PET와 발작기 SPECT의 간질원인병소 굴소화 및 편측화 진단성능을 조사하였다. 대상 및 방법: 침습적 뇌파검사와 수술과 수술 후 경과를 관찰하여 후두엽 간질로 진단된 17명의 환자를 대상으로 발작간기 F-l8-FDG PET (15명)와 발작기 뇌관류 Tc-99m-HMPAO SPECT를 시행하였다. 대사가 감소된 부분과 관류가 가장 증가된 곳을 간질원인병소로 진단하고 후두엽 병소를 제대로 진단한 경우 국소화에 병소쪽 반구의 다른 엽 또는 여러 엽을 지칭한 경우에 편측화에 성공하였다고 보아 국소화율과 편측화율을 조사하였다. 결과: F-18-FDG PET는 15명 중 9명(60%)에세 병측 후두엽을 국소화하였고 14명 (93%)을 편측화하였다. 발작기 뇌관류 SPECT는 17명 중 3명(18%)에서 국소화하였고 13명(76%)에서 편측화하였다. 자기공명영상에 병변이 발견되지 않았거나 발작기 SPECT가 정화하게 국소화하지 못한 경우에 추가적인 국소화 및 편측화 정보를 F-18-FDG PET에서 얻을 수 있었던 경우가 각각 5명, 8명이었다. 결론: 후두엽간질에서 발작기 뇌관류 SPECT로 병변쪽 반구를 편측화할 수 있었으나 F-18-FDG PET는 국소화와 편측화에 뛰어나 자기 공명영상에 병변이 발견되지 않는 경우를 포함하여 간질원인 병소를 찾는 데 크게 도움이 되었다.

• The Plant Pathology Journal
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• 제36권1호
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• pp.43-53
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• 2020

Ralstonia solanacearum (Rso) is a causal agent of bacterial wilt in Solanaceae crops worldwide including Republic of Korea. Rso virulence predominantly relies on type III secreted effectors (T3Es). However, only a handful of Rso T3Es have been characterized. In this study, we investigated subcellular localization of and manipulation of plant immunity by 8 Rso T3Es predicted to harbor a nuclear localization signal (NLS). While 2 of these T3Es elicited cell death in both Nicotiana benthamiana and N. tabacum, only one was dependent on suppressor of G2 allele of skp1 (SGT1), a molecular chaperone of nucleotide-binding and leucine-rich repeat immune receptors. We also identified T3Es that differentially regulate flg22-induced reactive oxygen species production and gene expression. Interestingly, several of the NLS-containing T3Es translationally fused with yellow fluorescent protein accumulated in subcellular compartments other than the cell nucleus. Our findings bring new clues to decipher Rso T3E function in planta.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3648-3658
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• 2023

The early localization of a fuel subassembly with a failed (wet rupture) fuel pin is very important in reactors to limit the associated radiological and operational consequences. This requires a fast and reliable system for failure detection and their localization in the core. In the Prototype Fast Breeder Reactor, the system specially designed for this purpose is Failed Fuel Location Modules (FFLM) housed in the control plug region. It identifies a failed sub-assembly by detecting the presence of delayed neutrons in the sodium from a failed sub-assembly. During the commissioning phase of PFBR, it is mandatory to demonstrate the FFLM effectiveness. The paper highlights the engineering and physics design aspects of FFLM and the integrated simulation towards its function demonstration with a source assembly containing a perforated metallic fuel pin. This test pin mimics a MOX pin of 1 cm² of geometrical defect area. At 10% power and 20% sodium flow rate, the counts rate in the BCCs of FFLM system range from 75 cps to 145 cps depending upon the position of DN source assembly. The model developed for the counts simulation is applicable to both metal and MOX pins with proper values of k-factor and escape coefficient.

• 대한핵의학회지
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• 제29권4호
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• pp.465-472
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• 1995

목적 : 원발성 부갑상선기능 항진증의 대부분의 원인인 부갑상선 선종의 유일한 완치는 수술이며 수술의 성패에 가장 중요한 것은 수술전의 정확한 ??소의 확인이다. 다양한 영상검사들이 동원되고있으나 각가 결점이 있고 가장 특이도가 높은 $^{201}T1-^{99m}Tc$감영 촬영방법도 검사방법등에 문제점이 있다. 이에 원발성 부갑상선기능 항진증 환자에게 최근에 사용되고있는 $^{99m}Tc$-Sestamibi 부갑상선 스캔의 유용성을 알아보고자 하였다. 대상 및 방법 : 19명의 부갑상선기능 항진증환자에서 모든 환자에게 초음파 검사, CT, $^{201}T1-^{99m}Tc$감영 촬영을 시행하고 그중 5명은 $^{99m}Tc$-Sestamibi 부갑상선 스캔을 시행하여 수술후 확진결과와 함께 비교하였다. 결과 : 초음파 검사와 CT 및 $^{201}T1-^{99m}Tc$감영 스캔은 19예중 각가 12예(67.1%), 14예(78.9%) 그리고 17예(89.5%)에서 병소확인이 가능하였고 $^{99m}Tc$-Sestamibi 부갑상선 스캔은 시행한 5예(100%) 모두에서 병소 확인이 가능하였다. 결론 : 이상의 결과로 $^{99m}Tc$-Sestamibi 부갑상선 스캔은 원발성 부갑상선기능 항진증의 수술전 병소확인에서 유용한 검사법으로 이용될 수 있으리라 사료된다.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.781-786
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• 2017

The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• Reproductive and Developmental Biology
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• 제38권2호
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• pp.71-77
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• 2014

The specific genetic modification in porcine somatic cells by gene targeting has been very difficult because of low efficiency of homologous recombination. To improve gene targeting, we designed three kinds of knock-out vectors with ${\alpha}1,3$-galactosyltransferase gene (${\alpha}1,3$-GT gene), DT-A/pGT5'/neo/pGT3', DT-A/NLS/pGT5'/neo/pGT3' and pGT5'/neo/ pGT3'/NLS. The knock-out vectors consisted of a 4.8-kb fragment as the 5' recombination arm (pGT5') and a 1.9-kb fragment as the 3' recombination arm (pGT3'). We used the neomycin resistance gene (neo) as a positive selectable marker and the diphtheria toxin A (DT-A) gene as a negative selectable marker. These vectors have a neo gene insertion in exon 9 for inactivation of ${\alpha}1,3$-GT locus. DT-A/pGT5'/neo/pGT3' vector contain only positive-negative selection marker with conventional targeting vector. DT-A/NLS/pGT5'/neo/pGT3' vector contain positive-negative selection marker and NLS sequences in upstream of 5' recombination arm which enhances nuclear transport of foreign DNA into bovine somatic cells. pGT5'/neo/pGT3'/NLS vector contain only positive selection marker and NLS sequence in downstream of 3' recombination arm, not contain negative selectable marker. For transfection, linearzed vectors were introduced into porcine ear fibroblasts by electroporation. After 48 hours, the transfected cells were selected with $300{\mu}g/ml$ G418 during 12 day. The G418-resistant colonies were picked, of which 5 colonies were positive for ${\alpha}1,3$-GT gene disruption in 3' PCR and southern blot screening. Three knock-out somatic cells were obtained from DT-A/NLS/ pGT5'/neo/pGT3' knock-out vector. Thus, these data indicate that gene targeting vector using nuclear localization signal and negative selection marker improve targeting efficiency in porcine somatic cells.

• Animal cells and systems
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• 제2권4호
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• pp.529-538
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• 1998

In order to analyze the intracellu1ar localization of specific RNA components of ribonucleoproteins (RNP) in Xenopus oocytes, a modified protocol of whole-mount in situ Hybridization is presented in this paper, Mitochondria specific 12S rRNA probe was used to detect the amplification and distribution of mitochondria in various stages of the oocyte life cycle, and the results were found to be consistent with previously known distribution of mitochondria. The results with other specific probes (U1 and U3 small nuclear RNAs, and 5S RNA) also indicate that this procedure is generally effective in localizing RNAs in RNP complexes even inside organelles. In addition, the RNA component of RNase MRP, the RNP with endoribo-nuclease activity, localize to the nucleus in various stages of the oocyte life cycle. Some of MRP RNA, however, were found to be localized to the special population of mitochondria near the nucleus, especially in the active stage of mitochondrial amplification. It suggests dual localization of RNase MRP in the nucleus and mitochondria, which is consistent with the proposed roles of RNase MRP in mitochondrial DNA replication and in rRNA processing in the nucleolus.