• Corrosion Science and Technology
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• 제20권4호
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• pp.210-229
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• 2021

To safely operate domestic nuclear power plants approaching the end of their design life, the material degradation management strategy of the components is important. Among studies conducted to improve the soundness of nuclear reactor components, research methods for understanding the degradation of reactor internals and preparing management strategies were surveyed. Since the IGSCC (Intergranular Stress Corrosion Cracking) initiation and propagation process is associated with metal dissolution at the crack tip, crack initiation sensitivity was decreased in the hydrogenated water with decreased crack sensitivity but occurrence of small surface cracks increased. A stress of 50 to 55% of the yield strength of the irradiated materials was required to cause IASCC (Irradiation Assisted Stress Corrosion Cracking) failure at the end of the reactor operating life. In the threshold-stress analysis, IASCC cracks were not expected to occur until the end of life at a stress of less than 62% of the investigated yield strength, and the IASCC critical dose was determined to be 4 dpa (Displacement Per Atom). The stainless steel surface oxide was composed of an internal Cr-rich spinel oxide and an external Fe and Ni-rich oxide, regardless of the dose and applied strain level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.800-813
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• 2021

With the advent of 5G communications, internet of vehicles technology has been widely used in vehicles. Then the dynamic spread of information between vehicles began to come into focus with more research. It is well known that the identification of nodes with great spread influence has always been a hot topic in the field of information spreading. Most of the existing work measures the propagation influence by degree centrality, betweenness centrality and closeness centrality. In this paper, we will identify influential vehicle nodes based on the mobility characteristics of vehicles to explore the information spreading between vehicles in VANETs. Different from the above methods, we mainly explore the influence of the radius of gyration and vehicle kilometers of travel on information spreading. We use a real vehicle trajectory data to simulate the information transmission process between vehicles based on the susceptible-infected-recovered SIR model. The experimental results show that the influence of information spreading does not enhance with increasing radius of gyration and vehicle kilometers of travel. The fact is that both the radius of gyration and the distance travelled have a significant influence on information spreading when they are close to the median. When the value of both is large or small, it has little influence on information spreading. In view of this results, we can use the radius of gyration and vehicle kilometers of travel to better facilitate the transmission of information between vehicles.

• 한국구조물진단유지관리공학회 논문집
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• 제25권4호
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• pp.20-27
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• 2021

이 연구에서는 강봉 트러스 시스템으로 보강된 조적벽체의 내진거동을 합리적으로 평가하기 위하여 범용프로그램인 Abaqus를 이용한 비선형 유한요소해석 절차를 제시하였다. 조적벽체의 유한요소 모델은 콘크리트 손상 소성(concrete damaged plasticity, CDP)모델 및 벽돌-모르타르 계면 특성은 Yang et al.이 제시한 조적 프리즘의 압축 및 인장의 응력-변형률 모델과 전단마찰모델을 기반으로 메소-스케일법을 적용하였다. 유한요소 해석결과를 다양한 변수조건에서 실험결과와 비교한 결과, 강봉 트러스 시스템으로 보강된 조적벽체의 균열진전, 파괴 모드, 강체회전 내력 및 최대내력 그리고 횡하중-횡변위 관계에 대한 실험결과와 잘 일치하였다. 따라서 제시된 유한요소해석 절차는 조적벽체의 내진보강 설계에 합리적으로 이용될 수 있다고 판단된다.

• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.29-43
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• 2021

본 연구에서 제약식프로그래밍을 이용하여 제약식 있는 동적계획법 모형을 푸는 한 방법을 제시한다. 현재 제약식 있는 동적계획법을 다루는 방법은 각 단계별 제약식들의 상태를 일반적인 동적계획법의 상태공간에 추가하여 마치 제약식이 없는 동적계획법 방식을 적용하는데 반해, 이 연구에서 제시하는 방식은 제약식의 상태가 제약식프로그래밍의 변수 도메인으로 표현되고 저장된다. 계산에 있어서도 일반적인 동적계획법의 벨만방정식의 해법과 함께 제약식을 다루기 위한 제약식프로그래밍의 확산-추론 방법을 사용하는 하이브리드 방식을 따른다. 이 두가지 방식의 비교를 위해 특별히 장기 자동차 렌탈 문제를 제시하고 이 문제의 단순화된 모형을 중심으로 다른 방식으로 해결하는 과정을 보고 그 장단점을 논한다.

• Geomechanics and Engineering
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• 제18권4호
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• pp.449-457
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• 2019

Physical model tests were first performed to investigate the failure pattern of multiple pillar-roof support system. It was observed in the physical model tests, pillars were design with the same mechanical parameters in model #1, cracking occurred simultaneously in panel pillars and the roof above barrier pillars. When pillars 2 to 5 lost bearing capacity, collapse of the roof supported by those pillars occurred. Physical model #2 was design with a relatively weaker pillar (pillar 3) among six pillars. It was found that the whole pillar-roof system was divided into two independent systems by a roof crack, and two pillars collapse and roof subsidence events occurred during the loading process, the first failure event was induced by the pillars failure, and the second was caused by the roof crack. Then, for a multiple pillar-roof support system, three types of failure patterns were analysed based on the condition of pillar and roof. It can be concluded that any failure of a bearing component would cause a subsidence event. However, the barrier pillar could bear the transferred load during the stress redistribution process, mitigating the propagation of collapse or cutting the roof to insulate the collapse area. Importantly, some effective methods were suggested to decrease the risk of catastrophic collapse, and the deep-hole-blasting was employed to improve the stability of the pillar and roof support system in a room and pillar mine.

• 한국정보통신학회논문지
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• 제22권11호
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• pp.1442-1447
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• 2018

RFID를 이용한 실내 위치 인식 시스템은 실내의 위치를 예측하는 방식이기 때문에 장애물 등 주변 환경에 의해 오차가 발생한다. 본 논문에서는 역전파 신경망을 이용하여 오차를 줄이고자 한다. 신경망은 층간의 가중치를 조정하고 훈련시켜 리더를 보유한 물체의 실제위치와 실험을 통해 예상되는 위치간의 오차를 줄인다. 본 논문에서는 중앙값을 사용한 방법과 방사 형태를 사용한 방법을 신경망의 입력으로 사용하는 구성을 제안하였다. 두 가지 방법 중 장애물이 있는 환경에서 어떤 방법이 실제 위치를 인식하는 데에 더 효율적인지 확인하고 오차를 줄이고자 한다. 그 결과 중앙값을 이용한 방법이 오차가 더 적었으며, 데이터 개수가 많을수록 오차가 더 줄어드는 것을 확인하였다.

• Animal Bioscience
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• 제34권2호
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• pp.265-275
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• 2021

Objective: The study developed mushroom stalk residues as feed additives in the broiler diet for improving the growth performance and immunity of broilers as well as to increase the value of mushroom stalk residues. Methods: In total, 300 ROSS 308 broilers were randomly allocated into fifteen pens with five dietary treatments: i) control, basal diet; ii) CMWM, supplemented with 1% Cordyceps militaris waster medium (CM); iii) CMPE, supplemented with 0.5% CM+0.5% Pleurotus eryngii stalk residue (PE); iv) CMPS, supplemented with 0.5% CM+0.5% Pleurotus sajorcaju stalk residue (PS); v) CMFV, supplemented with 0.5% CM+0.5% Fammulina velutipes stalk residue (FV). Results: The chemical analysis results showed that CM extracts, PE extracts, PS extracts, and FV extracts contain functional components such as polysaccharides and phenols and have both 2, 2-diphenyl-1-picryl-hydrazyl-hydrate scavenging and Ferrous scavenging capacities. The group CMWM saw increased body weight gain and feed conversion rate and the promotion of jejunum villus growth, but there is no significant difference in the intestinal bacteria phase. Antioxidant genes in the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)- antioxidant responsive element pathway among the groups are significantly higher than that of the control group, especially in group CMWM. Conclusion: The mushroom stalk residues have antioxidant functional components, can improve the intestinal health and body weight gain of chickens, and can activate the antioxidant pathway of Nrf2 to increase the heme oxygenase-1 expression. The treatment with 1% CM was the most promising as a feed additive.

• Earthquakes and Structures
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• 제20권1호
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• pp.71-86
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• 2021

This paper focuses on the development and assessment of the expected damage for the rocking response of rigid anchored blocks, with irregular geometry and non-uniform mass distribution, considering the site conditions and the seismicity of Mexico City. The non-linear behavior of the restrainers is incorporated to evaluate the pure tension and tension-shear failure mechanisms. A probabilistic framework is performed covering a wide range of block sizes, slenderness ratios and eccentricities using physics-based ground motion simulation. In order to incorporate the uncertainties related to the propagation of far-field earthquakes with a significant contribution to the seismic hazard at study sites, it was simulated a set of scenarios using a stochastic summation methods of small-earthquakes records, considered as Empirical Green's Function (EGFs). As Engineering Demand Parameter (EDP), the absolute value of the maximum block rotation normalized by the body slenderness, as a function of the peak ground acceleration (PGA) is adopted. The results show that anchorages are more efficient for blocks with slenderness ratio between two and three, while slenderness above four provide a better stability when they are not restrained. Besides, there is a range of peak intensities where anchored blocks located in soft soils are less vulnerable with respect to those located in firm soils. The procedure used in here allows to take decisions about risk, reliability and resilience assessment of different types of contents, and it is easily adaptable to other seismic environments.

• Animal Bioscience
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• 제34권7호
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• pp.1157-1168
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• 2021

Objective: The aim of this study was to investigate the effects of different amounts of wheat bran (WB) inclusion and postbiotics form by Saccharomyces cerevisiae and phytase co-fermented wheat bran (FWB) on the growth performance and health status of broilers. Methods: Study randomly allocated a total of 300 male broilers to a control and 4 treatment groups (5% WB, 5% FWB, 10% WB, and 10% FWB inclusion, respectively) with each pen having 20 broilers and 3 pens per treatment. Results: The WB does not contain enzymes, but there are 152.8, 549.2, 289.5, and 147.1 U/g dry matter xylanase, protease, cellulase and β-glucanase in FWB, respectively. Furthermore, FWB can decrease nitric oxide release of lipopolysaccharide stimulated chicken peripheral blood mononuclear cells by about two times. Results show that 10% FWB inclusion had significantly the highest weight gain (WG) at 1 to 21 d; 5% FWB had the lowest feed conversion rate at 22 to 35 d; 10% WB and 10% FWB inclusion have the highest villus height and Lactobacillus spp. number in caecum; and both 5% and 10% FWB can increase ash content in femurs. Compared to control group, all treatments increase mucin 2, and tight junction (TJ), such as occludin, claudin-1, zonula occludens-1, and mRNA expression in ileum by at least 5 folds. In chicken peripheral blood mononuclear cells, nicotinamide adenine dinucleotide phosphate-oxidase-1 mRNA expression decreases from 2 to 5 times, and glutamate-cysteine ligase catalytic subunit mRNA expression also increases in all treatment groups compared to control group. The mRNA expression of pro-inflammatory cytokines, including interleukin-6 (IL-6), nuclear factor-κB, and IL-1β, decreases in 5% and 10% FWB groups compared to control group. Conclusion: To summarize, both WB and FWB inclusion in broilers diets increase TJ mRNA expression and anti-oxidation and anti-inflammation, but up to 10% FWB groups have better WG in different stages of broiler development.

• 융합신호처리학회논문지
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• 제21권3호
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• pp.113-120
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• 2020

최근 통신장비가 발달함에 따라 통신장비의 수요가 점차 늘어나고 있는 추세이다. 이에 따라 다양한 신호 처리가 연구되어져 왔다. 그 중 영상은 전처리 과정에서 잡음을 제거하지 않으면 오류의 전파라는 문제를 야기할 수 있기 때문에 잡음 제거가 필수불가결한 단계이다. Salt and Pepper 잡음의 경우 두 개의 극값을 가지는 대표적인 임펄스 잡음이다. 이러한 잡음을 제거하기 위해 다양한 연구가 진행되어 왔으며 CWMF, MF, MMF 등이 있다. 하지만 기존의 방법들은 고밀도 잡음 영역에서 다소 미흡한 모습을 보인다. 따라서 본 연구에서는 7×7 마스크 내부의 잡음개수에 따라 마스크의 크기를 다르게 하고, 영상의 히스토그램 분포를 이용하여 변형된 스위칭 필터로 필터링하는 알고리즘을 제안하였다. 제안한 알고리즘의 경우 고밀도 잡음 영역에서 효과적으로 잡음을 제거할 수 있으며, 객관적인 판단을 위해 PSNR을 이용하여 기존의 알고리즘들과 비교, 분석하였다.