• 산업공학
• /
• 제13권4호
• /
• pp.751-758
• /
• 2000

Situation awareness is defined as a person's perception of the elements of the environment within a volume of time and space, the comprehension of their meaning and the projection of their status in the near future. Situation awareness is important in attempting to evaluate human behavior in operating complex systems such as aircraft, air traffic control, and nuclear power plant systems. From the literatures this study reviews the relationship between situation awareness and numerous individual, system and environmental factors, and also reviews the methodologies for the empirical measurement of situation awareness applicable to Korea Next Generation Reactor (KNGR) design project. Attention, working memory, workload, stress, system complexity, and automation are presented as critical factors limiting operator's situation awareness. Mental models and goal-directed behavior are hypothesized as important mechanisms overcoming these limits. This study summarized hypothesized guidelines for interface design to improve situation awareness of reactor operators. Some of the guidelines should be tested in the KNGR evaluation experiments in the future.

• 한국지능시스템학회논문지
• /
• 제12권3호
• /
• pp.246-254
• /
• 2002

In this paper auto-tuning scheme of PID controller based on the reference model has been studied for a Process control system by immune algorithm. Up to this time, many sophisticated tuning algorithms have been tried in order to improve the PID controller performance under such difficult conditions. Also, a number of approaches have been proposed to implement mixed control structures that combine a PID controller with fuzzy logic. However, in the actual plant, they are manually tuned through a trial and error procedure, and the derivative action is switched off. Therefore, it is difficult to tune. Since the immune system possesses a self organizing and distributed memory, it is thus adaptive to its external environment and allows a PDP (Parallel Distributed Processing) network to complete patterns against the environmental situation. Simulation results reveal that reference model basd tuning by immune network suggested in this paper is an effective approach to search for optimal or near optimal process control.

• 대한한의학회지
• /
• 제25권4호
• /
• pp.95-107
• /
• 2004

Objective : The inappropriate or excessive apoptosis has been known to be associated with neurodegenerative disorders including intracranial hemorrhage(ICH). Paeoniae radix, in traditional Korean medicine, has played its role as blood­nourisher and yin-astringent. In the present study, the effect of Paeoniae radix on the inhibition of neurodegeneration in the brain of rats after artificial ICH and on the resulting apoptosis was investigated. Methods : 30 rats were divided into 6 equal groups ; the sham-operation group, the hemorrhage-induction group, the hemorrhage-induction with 10, 50, 100, and 200 mg/kg Paeoniae radix-treated group, respectively. Stereotactic surgery was performed and collagenase was infused to induce ICH in the region of CA1 of hippocampus of rats. The sham group took only saline infusion. For 7 days after the surgery, 4 testing groups had intraperitoneal injections of Paeoniae radix extract. The step-down inhibitory avoidance task, measurement of neurodegeneration degree in the CA1 region of the hippocampus, and detection of caspase-3 and newly generated cells in the dentate gyrus were done after animal sacrifice. Results : Rats receiving Paeoniae radix extract showed increased latency time in the inhibitory avoidance task. The extension of neuron-deprived areas in the CA1 region was significantly suppressed in the Paeonia treated groups. Also expressions of caspase-3 in the CA1 region and cortex were significantly inhibited in the Paeonia treated groups. The cell proliferation was evaluated by means of BrdU methods and proved to be decreased in the Paeonia treated groups. Conclusion : These results suggest that Paeoniae radix has potential to suppress short-tenn memory loss after devastating neurologic accidents. Also it was proved that Paeoniae radix has a neuroprotective effect and alleviates central nervous complications following intracerebral hemorrhage. Furthermore, it may imply that this medicinal plant can be widely used for vascular dementia and other neurodegenerative disorders.

• Nutrition Research and Practice
• /
• 제10권3호
• /
• pp.274-281
• /
• 2016

BACKGROUND/OBJECTIVES: The accumulation of amyloid-${\beta}$ ($A{\beta}$) in the brain is a hallmark of Alzheimer's disease (AD) and plays a key role in cognitive dysfunction. Perilla frutescens var. japonica extract (PFE) and its major compound, rosmarinic acid (RA), have shown antioxidant and anti-inflammatory activities. We investigated whether administration of PFE and RA contributes to cognitive improvement in an $A{\beta}_{25-35}$-injected mouse model. MATERIALS/METHODS: Male ICR mice were intracerebroventricularly injected with aggregated $A{\beta}_{25-35}$ to induce AD. $A{\beta}_{25-35}$-injected mice were fed PFE (50 mg/kg/day) or RA (0.25 mg/kg/day) for 14 days and examined for learning and memory ability through the T-maze, object recognition, and Morris water maze test. RESULTS: Our present study demonstrated that PFE and RA administration significantly enhanced cognition function and object discrimination, which were impaired by $A{\beta}_{25-35}$, in the T-maze and object recognition tests, respectively. In addition, oral administration of PFE and RA decreased the time to reach the platform and increased the number of crossings over the removed platform when compared with the $A{\beta}_{25-35}$-induced control group in the Morris water maze test. Furthermore, PFE and RA significantly decreased the levels of nitric oxide (NO) and malondialdehyde (MDA) in the brain, kidney, and liver. In particular, PFE markedly attenuated oxidative stress by inhibiting production of NO and MDA in the $A{\beta}_{25-35}$-injected mouse brain. CONCLUSIONS: These results suggest that PFE and its active compound RA have beneficial effects on cognitive improvement and may help prevent AD induced by $A{\beta}$.

• 한국인터넷방송통신학회논문지
• /
• 제19권1호
• /
• pp.29-35
• /
• 2019

4차 산업 혁명이 진행되며 많은 회사들의 스마트 팩토리에 대한 관심이 커지고 있으며 센서의 중요성 또한 대두되고 있다. 정보를 수집하기 위한 센서에서 고장이 발생하면 공장을 최적화하여 운영할 수 없기 때문에 이에 따른 손해가 발생할 수 있다. 이를 위해 센서의 상태를 진단하여 센서의 고장을 진단하는 일이 필요하다. 본 논문에서는 디지털 센서의 고장유형 중 Rising time과 Falling time 고장을 딥러닝 알고리즘 RNN의 LSTM을 통해 신호를 분석하여 고장을 진단하는 모델을 제안한다. 제안한 방식의 실험 결과를 정확도와 ROC 곡선 그래프의 AUC(Area under the curve)를 이용하여 Rule 기반 고장진단 알고리즘과 비교하였다. 실험 결과, 제안한 시스템은 Rule 기반 고장진단 알고리즘 보다 향상되고 안정된 성능을 보였다.

• Nutrition Research and Practice
• /
• 제15권2호
• /
• pp.173-186
• /
• 2021

BACKGROUD/OBJECTIVES: Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Due to the increased incidence of dementia, there is a corresponding increase concerning the importance of AD. In this study, we investigated the protective effects conferred by Zizyphus jujuba (Zj) and Zizyphus jujuba fermented by yeast (Zj-Y), on cognitive impairment in an AD mouse model. MATERIALS/METHODS: AD was induced by injecting amyloid beta25-35 (Aβ25-35) in ICR mice, and subsequently 200 mg/kg Zj or Zj-Y was administered daily for 14 days. The cognitive ability of AD mice was observed through behavioral experiments in T-maze, novel object recognition, and Morris water maze tests. We subsequently measured the levels of malondialdehyde (MDA), nitric oxide (NO), aspartate aminotransferase, and alanine aminotransferase in either tissues or serum. RESULTS: In behavioral tests, deterioration was revealed in the short- and long-term learning and memory functions in the Aβ25-35-injected control group compared to the normal group, indicating that Aβ25-35 injection impairs cognitive functions. However, administration of Zj and Zj-Y improved cognitive function in mice, as compared to the Aβ25-35-injected control mice. In addition, the Aβ25-35 induced elevations of MDA and NO in the brain, kidney, and liver were suppressed after exposure to Zj and Zj-Y. Especially, Zj-Y showed stronger scavenging effect against MDA and NO, as compared to Zj. CONCLUSIONS: Results of the present study indicate that Zj-Y exerts a protective effect on cognitive impairment and memory dysfunction, which is exerted by attenuating the oxidative stress induced by Aβ25-35.

• 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.

• Structural Engineering and Mechanics
• /
• 제81권6호
• /
• pp.691-703
• /
• 2022

To obtain the seismic response of lead-cored rubber, shape memory alloy (SMA)-rubber isolation Plate-shell Integrated Concrete Liquid-Storage Structure (PSICLSS), based on a PSICLSS in a water treatment plant, built a scale experimental model, and a shaking table test was conducted. Discussed the seismic responses of rubber isolation, SMA-rubber isolation PSICLSS. Combined with numerical model analysis, the vibration characteristics of rubber isolation PSICLSS are studied. The results showed that the acceleration, liquid sloshing height, hydrodynamic pressure of rubber and SMA-rubber isolation PSICLSS are amplified when the frequency of seismic excitation is close to the main frequency of the isolation PSICLSS. The earthquake causes a significant leakage of liquid, at the same time, the external liquid sloshing height is significantly higher than internal liquid sloshing height. Numerical analysis showed that the low-frequency acceleration excitation causes a more significant dynamic response of PSICLSS. The sinusoidal excitation with first-order sloshing frequency of internal liquid causes a more significant sloshing height of the internal liquid, but has little effect on the structural principal stresses. The sinusoidal excitation with first-order sloshing frequency of external liquid causes the most enormous structural principal stress, and a more significant external liquid sloshing height. In particular, the principal stress of PSICLSSS with long isolation period will be significantly enlarged. Therefore, the stiffness of the isolation layer should be properly adjusted in the design of rubber and SMA-rubber isolation PSICLSS.

• Nuclear Engineering and Technology
• /
• 제55권9호
• /
• pp.3423-3440
• /
• 2023

In this work, a multivariate time-series machine learning meta-model is developed to predict the transient response of a typical nuclear power plant (NPP) undergoing a steam generator tube rupture (SGTR). The model employs Recurrent Neural Networks (RNNs), including the Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), and a hybrid CNN-LSTM model. To address the uncertainty inherent in such predictions, a Bayesian Neural Network (BNN) was implemented. The models were trained using a database generated by the Best Estimate Plus Uncertainty (BEPU) methodology; coupling the thermal hydraulics code, RELAP5/SCDAP/MOD3.4 to the statistical tool, DAKOTA, to predict the variation in system response under various operational and phenomenological uncertainties. The RNN models successfully captures the underlying characteristics of the data with reasonable accuracy, and the BNN-LSTM approach offers an additional layer of insight into the level of uncertainty associated with the predictions. The results demonstrate that LSTM outperforms GRU, while the hybrid CNN-LSTM model is computationally the most efficient. This study aims to gain a better understanding of the capabilities and limitations of machine learning models in the context of nuclear safety. By expanding the application of ML models to more severe accident scenarios, where operators are under extreme stress and prone to errors, ML models can provide valuable support and act as expert systems to assist in decision-making while minimizing the chances of human error.

• 한국식품영양과학회지
• /
• 제43권3호
• /
• pp.360-366
• /
• 2014

김치의 EtOH 추출물을 이용하여 in vitro 상에서 DPPH와 ${\cdot}OH$ radical 소거능을 측정하였고, ICR mouse의 해마 부위에 $A{\beta}$를 주입시킨 AD model을 이용하여 김치 추출물을 2주간 투여한 후 물체 인지, T-maze, water maze의 실험방법을 이용하여 인지능력 개선 효과를 살펴보았다. 김치추출물은 우수한 DPPH와 ${\cdot}OH$ radical 소거능을 나타내었다. 또한 AD 동물 model에서 해마 부위에 $A{\beta}$를 주입한 control군의 경우 물체 인지, 기억 및 학습능력의 손상을 확인할 수 있었으나, 김치 추출물을 100과 200 mg/kg/day를 투여한 군에서는 물체 인지 실험에서 새로운 물체에 대한 호기심 정도가 높았으며, T-maze 실험에서는 새로운 길에 대한 탐색 정도도 뛰어난 것을 확인할 수 있었다. Water maze 실험에서도 도피대를 찾아가는 반복 훈련을 할수록 도피대를 찾아가는 시간이 점차 단축되는 것을 확인할 수 있었으며, 도피대를 기억하는 능력도 향상됨을 확인할 수 있었다. 본 연구 결과에서는 김치 추출물이 radical을 소거함으로써 산화적 스트레스로부터 보호하여 인지능력 및 기억능력을 향상시키는 효과가 있음을 확인하였다. 이러한 연구를 바탕으로 김치의 산화적 스트레스 개선 효과 및 AD 예방에 대한 상관관계에 대한 작용기작 연구가 이루어진다면 우리나라 대표 식품인 김치의 섭취로 인한 AD 예방 효과에 대해 명확하게 규명할 수 있을 것으로 사료되어진다.