• 한국정보전자통신기술학회논문지
• /
• 제15권5호
• /
• pp.367-379
• /
• 2022

본 논문에서는 입자 군집 최적화 (Particle Swarm Optimization: PSO) 알고리즘을 이용하여 다층 레이더 흡수 구조체를 설계하고, 다층 레이더 흡수 구조체의 특성을 분석하였다. 다층 레이더 흡수 구조체 설계에 PSO를 적용함으로써 빠르고 정확하게 설계 값을 도출할 수 있음을 보였으며, 특히 경사 입사에 대한 경우에 대해서도 최적의 다층 레이더 흡수 구조체를 설계할 수 있음을 보였다. 또한, 다양한 설계 파라미터의 조합에서도 성능 요구 조건에 부합하는 최적의 값이 결정될 수 있음을 보였다. 각 단계별로 필요한 방정식 및 모든 변수에 대한 자세한 설명을 포함해서 포괄적인 순서도를 통해 제시하였고 본 논문의 결과로부터 다층 레이더 흡수 구조체를 설계하기 위한 복잡하고 많은 계산을 생략할 수 있으며, 다양한 복합 재료를 활용한 다층 레이다 흡수 구조체 설계 및 개발에 활용할 수 있다.

• Nuclear Engineering and Technology
• /
• 제54권9호
• /
• pp.3516-3525
• /
• 2022

The high capture cross-section (𝜎_c) of Gadolinium (Gd-155 and Gd-157) causes reactivity penalty and swing at the initial stage of fuel burnup in Pressurized Water Reactor (PWR). The present study is concerned with the feasibility of the combination of mixed burnable poison with both low and high 𝜎_c as an approach to minimize these effects. Two considered reference designs are fuel assemblies with 24 IBA rods of Gd₂O₃ and Er₂O₃ respectively. Models comprise nuclear fuel with a homogeneous mixture of Er₂O₃, AmO₂, SmO₂, and HfO₂ with Gd₂O₃ as well as the coating of PaO₂ and ZrB₂ on the Gd₂O₃ pellet's outer surface. The infinite multiplication factor was determined and reactivity was calculated considering 3% neutron leakage rate. All models except Er₂O₃ and SmO₂ showed expected results namely higher values of these parameters than the reference design of Gd₂O₃ at the early burnup period. The highest value was found for the model of PaO₂ and Gd₂O₃ followed by ZrB₂ and HfO₂. The cycle burnup, discharge burnup, and cycle length for three batch refueling were calculated using Linear Reactivity Model (LRM). The pin power distribution, energy-dependent neutron flux and Fuel Temperature Coefficient (FTC) were also studied. An optimization of model 1 was carried out to investigate effects of different isotopic compositions of Gd₂O₃ and absorber coating thickness.

• 디지털융복합연구
• /
• 제19권5호
• /
• pp.315-320
• /
• 2021

다양한 목적의 블록체인 플랫폼이 개발되어 블록체인 생태계가 발전되는 와중에 각 블록체인들이 고립돼서 운용되는 상호운용성 문제가 나타나고 있다. 이에 본 연구에서 블록체인들을 연결해주는 블록체인인 인터체인과 사이드체인 기술을 소개하고 이를 적용함으로써 이기종 블록체인간 거래와 기능을 사용하는 예를 설명하였다. 또한, 4차 산업혁명에서 주목받는 기술인 블록체인, 인공지능, IoT 각각의 기술들이 독자적인 발전과정을 넘어서서 서로 융합하여 발전하는 과정을 거치고 있다. 이에 대해서 블록체인에 인공지능을 또는 IoT가 결합하는 과정들을 제시하고 더불어 블록체인과 인공지능 IoT의 결합을 이기종 블록체인간의 거래와 교류를 위한 과정에 적용해서 개입 없이 작동할 수 있는 모델을 제안하였다.

• 시스템엔지니어링학술지
• /
• 제18권2호
• /
• pp.75-93
• /
• 2022

Machine learning (ML) data-driven meta-model is proposed as a surrogate model to reduce the excessive computational cost of the physics-based model and facilitate the real-time prediction of a nuclear power plant's transient response. To forecast the transient response three machine learning (ML) meta-models based on recurrent neural networks (RNNs); specifically, Long Short Term Memory (LSTM), Gated Recurrent Unit (GRU), and a sequence combination of Convolutional Neural Network (CNN) and LSTM are developed. The chosen accident scenario is a control element assembly withdrawal at power concurrent with the Loss Of Offsite Power (LOOP). The transient response was obtained using the best estimate thermal hydraulics code, MARS-KS, and cross-validated against the Design and control document (DCD). DAKOTA software is loosely coupled with MARS-KS code via a python interface to perform the Best Estimate Plus Uncertainty Quantification (BEPU) analysis and generate a time series database of the system response to train, test and validate the ML meta-models. Key uncertain parameters identified as required by the CASU methodology were propagated using the non-parametric Monte-Carlo (MC) random propagation and Latin Hypercube Sampling technique until a statistically significant database (181 samples) as required by Wilk's fifth order is achieved with 95% probability and 95% confidence level. The three ML RNN models were built and optimized with the help of the Talos tool and demonstrated excellent performance in forecasting the most probable NPP transient response. This research was guided by the Systems Engineering (SE) approach for the systematic and efficient planning and execution of the research.

• 사상체질의학회지
• /
• 제34권3호
• /
• pp.41-49
• /
• 2022

Background Abdominal obesity, a major public health concern, is related to many health problems. In addition, it is influenced by individual characteristics. We investigated sleep quality and physical activity (PA) as risk factors for abdominal obesity, according to the Sasang constitutional medicine. Methods In this cross-sectional study, we analyzed data from 5,221 community-based participants. Sleep quality and PA were measured using structured questionnaires, and abdominal obesity was classified according to waist circumference. Sasang constitution (SC) was classified as Taeeumin (TE), Soeumin (SE), or Soyangin (SY) type, using an established SC questionnaire. Chi-square test and logistic regression analysis were performed to access the association of sleep quality and PA with abdominal obesity in individuals stratified according to the SC types. Results The percentage of poor sleep quality and inactive PA was the highest in the SE type, and the higher prevalence of abdominal obesity was found in the TE type. After adjusting for variables, inactive PA was associated with abdominal obesity in the TE type (OR=1.694, 95% CI=1.42-2.021), and in the SE type, abdominal obesity was associated with poor sleep quality (OR=1.688, 95% CI=1.091-2.611) and low PA (OR=2.127, 95% CI=1.163-3.89). Moreover, the combination of these two factors were also significantly associated with abdominal obesity in the TE and SE types. Conclusion Abdominal obesity was associated with sleep quality and PA, and these results were different in each SC type. Taking various associated lifestyles and individual characteristics in consideration may contribute to better management of abdominal obesity in clinical practice.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권2호
• /
• pp.391-411
• /
• 2023

Aggregates play the skeleton and supporting role in the construction field, high-precision measurement and high-efficiency analysis of aggregates are frequently employed to evaluate the project quality. Aiming at the unbalanced operation time and segmentation accuracy for multi-class segmentation algorithms of aggregate images, a Chaotic Sparrow Search Algorithm (CSSA) is put forward to optimize it. In this algorithm, the chaotic map is combined with the sinusoidal dynamic weight and the elite mutation strategies; and it is firstly proposed to promote the SSA's optimization accuracy and stability without reducing the SSA's speed. The CSSA is utilized to optimize the popular multi-class segmentation algorithm-Multiple Entropy Thresholding (MET). By taking three METs as objective functions, i.e., Kapur Entropy, Minimum-cross Entropy and Renyi Entropy, the CSSA is implemented to quickly and automatically calculate the extreme value of the function and get the corresponding correct thresholds. The image adaptive multi-class segmentation model is called CSSA-MET. In order to comprehensively evaluate it, a new parameter I based on the segmentation accuracy and processing speed is constructed. The results reveal that the CSSA outperforms the other seven methods of optimization performance, as well as the quality evaluation of aggregate images segmented by the CSSA-MET, and the speed and accuracy are balanced. In particular, the highest I value can be obtained when the CSSA is applied to optimize the Renyi Entropy, which indicates that this combination is more suitable for segmenting the aggregate images.

• The Journal of Advanced Prosthodontics
• /
• 제15권4호
• /
• pp.171-178
• /
• 2023

PURPOSE. The purpose of this study was to determine the effect of the connector configuration on the fracture load in conventional and translucent zirconia of three-unit fixed dental prostheses (FDPs). MATERIALS AND METHODS. Six different three-unit FDPs were prepared (n = 6) from three types of zirconia (3Y-TZP (Katana ML^®), 4Y-TZP (Katana STML^®), and 5Y-TZP (Katana UTML^®)) in combination with two connector configurations (4 × 2.25, 3 × 3 mm). The CoCr master models were scanned, and the FDPs were designed and fabricated using CAD-CAM. The FDPs were cemented on the metal model and then loaded with a UTM at a crosshead speed of 1 mm/min until failure. Two-way ANOVA and Tukey's test were used for statistical analysis (α = .05). RESULTS. Fracture loads of 3Y-TZP (2740.6 ± 469.2 and 2718.7 ± 339.0 N for size 4 × 2.25 mm and 3 × 3 mm, respectively) were significantly higher than those of 4Y-TZP (1868.3 ± 281.6 and 1663.6 ± 372.7 N, respectively) and 5Y-TZP (1588.0 ± 255.0 and 1559.1 ± 110.0 N, respectively) (P < .05). No significant difference was found between fracture loads of 4Y-TZP and 5Y-TZP (P > .05). The connector configuration within 9 mm² was found to have no effect on the fracture loads on all three types of zirconia (P > .05). CONCLUSION. Fracture loads of three-unit FDPs were affected by the type of zirconia. The fracture loads of conventional zirconia were higher than those of translucent zirconia. However, it was not affected by the connector configuration when the connector had a cross-sectional area of 9 mm².

• 한국식품과학회지
• /
• 제54권1호
• /
• pp.66-74
• /
• 2022

β-Carotene의 용해도를 증진시키기 키토산을 기본 피복물질로 사용하면서 TPP와 HA를 단독 또는 복합적으로 사용하여 세 종류(CS/TPP, CS/TPP/HA와 CS/HA)의 나노캡슐을 제조하였다. 모든 종류의 나노캡슐에서 95%가 넘는 높은 포집효율이 관측되었다. β-Carotene 에멀젼의 저장안정성이 취약한 pH 2-3 조건에서 8일동안 저장하였을 때 CS/TPP/HA와 CS/HA 나노캡슐의 물리적 특성뿐만 아니라 β-carotene의 용해도 또한 안정적으로 유지되는 경향을 나타냈다. β-Carotene의 용해도를 나노캡슐의 건조 전과 후 관측한 결과, 대조군에 비해서 나노캡슐화에 의해서 유의적으로 향상된 것을 확인할 수 있었다. 특히 CS/HA 나노캡슐은 용해도와 재분산성의 측면에서 모두 우수한 특성을 나타냈다. 본 연구를 통해서 CS/HA 나노캡슐은 β-carotene과 같은 난용성 활성성분의 용해도를 증진시킬 수 있는 식품산업에 활용가능한 전달체로서 이용 가능성이 높을 것으로 판단된다.

• Geomechanics and Engineering
• /
• 제34권1호
• /
• pp.103-113
• /
• 2023

This study focused on understanding the relationship between the design of a tunnel boring machine disc cutter ring and its rock-breaking efficiency, as well as the applicable conditions of different cutter ring types. The discrete element method was used to establish a numerical model of the rock-breaking process using disc cutters with different ring types to reveal the development of rock damage cracks and variation in cutter penetration load. The calculation results indicate that a sharp-edged (V-shaped) disc cutter penetrates a rock mass to a given depth with the lowest load, resulting in more intermediate cracks and few lateral cracks, which leads to difficulty in crack combination. Furthermore, the poor wear resistance of a conventional V-shaped cutter can lead to an exponential increase in the penetration load after cutter ring wear. In contrast, constant-cross-section (CCS) disc cutters have the highest quantity of crack extensions after penetrating rock, but also require the highest penetration loads. An arch-edged (U-shaped) disc cutter is more moderate than the aforementioned types with sufficient intermediate and lateral crack propagation after cutting into rock under a suitable penetration load. Additionally, we found that the cutter ring wedge angle and edge width heavily influence cutter rock-breaking efficiency and that a disc cutter with a 16 to 22 mm edge width and 20° to 30° wedge angle exhibits high performance. Compared to V-shaped and U-shaped cutters, the CCS cutter is more suitable for soft or medium-strength rocks, where the penetration load is relatively small. Additionally, two typical case studies were selected to verify that replacing a CCS cutter with a U-shaped or optimized V-shaped disc cutter can increase cutting efficiency when encountering hard rocks.

• 한국해양생명과학회지
• /
• 제2권2호
• /
• pp.83-89
• /
• 2017

In abalones, interspecific hybridization has been suggested as a possible means to increase production and desired traits for the industry. In Korea, Haliotis gigantea is considered a species with a larger size and higher temperature tolerance than H. discus hannai. However, H. discus hannai is considered the most valuable and popular fishery resource due to its better acceptance and higher market prices. Thus, viable interspecific hybrids have been produced by artificial inseminating H. gigantea eggs with H. discus hannai sperm. However, the reciprocal hybrid cross was not successful. In this study, the hybridity and the growth and thermal tolerance performance of the interspecific hybrids were examined. A combination of various assays revealed maximum growth occurrence at 21℃ and the higher growth rate in the hybrids than that of H. discus hannai parent. In addition, the growth and survival at high-temperature (28℃) of the hybrids was equivalent to that of the highly tolerant H. gigantea parent, suggesting new possibilities to overcome the mass mortality in H. discus hannai during high temperature periods of summer season in Korea. Furthermore, the induced interspecific hybrid status was confirmed by the presence of species-specific bands for each parental species of the random amplified polymorphic DNA (RAPD) profiles using universal rice primer (URP), which could be used as speciesspecific markers to distinguish the hybrids and their parental species.