• 대한한방내과학회지
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• 제29권3호
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• pp.608-620
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• 2008

Objectives : This study investigated the protective effects of the water extracts of Chongmyung-tang, Polygalae Radix, and Acori Graminei Rhizoma in an in vivo Alzheimer's disease (AD) mouse model. Methods : Memory impairment was induced by an intraventricular injection of $A{\beta}25-35$ peptides and subsequently Chongmyung-tang, Polygalae Radix, or Acori Graminei Rhizoma extract were administered orally for 14days. Results : In the water maze task, Chongmyung-tang, Polygalae Radix, and Acori Graminei Rhizoma extracts improved learning ability during the acquisition period and significantly increased memory scores during the retention period versus $A{\beta}-injected$ controls. Furthermore, the toxicity of $A{\beta}25-35$ on hippocampus was assessed immunohistochemically (Tau, MAP2, TUNEL, Bax) and by in vitro study. Chongmyung-tang, Polygalae Radix, and Acori Graminei Rhizoma demonstrated significant neuroprotective effects against oxidative damage and apoptotic cell death of hippocampal neurons damaged by $A{\beta}25-35$. Conclusions : These results suggested that Chongmyung-tang, Polygalae Radix and Acori Graminei Rhizoma extract improve memory impairment and reduce Alzheimer's dementia via anti-apoptotic effects and by modulating the expressions of Tau and MAP2 protein in the hippocampus.

• Biomolecules & Therapeutics
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• 제26권2호
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• pp.109-114
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• 2018

Liquiritigenin (LQ) is a flavonoid that can be isolated from Glycyrrhiza radix. It is frequently used as a tranditional oriental medicine herbal treatment for swelling and injury and for detoxification. However, the effects of LQ on cognitive function have not been fully explored. In this study, we evaluated the memory-enhancing effects of LQ and the underlying mechanisms with a focus on the N-methyl-D-aspartic acid receptor (NMDAR) in mice. Learning and memory ability were evaluated with the Y-maze and passive avoidance tests following administration of LQ. In addition, the expression of NMDAR subunits 1, 2A, and 2B; postsynaptic density-95 (PSD-95); phosphorylation of $Ca^{2+}$/calmodulin-dependent protein kinase II (CaMKII); phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2); and phosphorylation of cAMP response element binding (CREB) proteins were examined by Western blot. In vivo, we found that treatment with LQ significantly improved memory performance in both behavioral tests. In vitro, LQ significantly increased NMDARs in the hippocampus. Furthermore, LQ significantly increased PSD-95 expression as well as CaMKII, ERK, and CREB phosphorylation in the hippocampus. Taken together, our results suggest that LQ has cognition enhancing activities and that these effects are mediated, in part, by activation of the NMDAR and CREB signaling pathways.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권11호
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• pp.2849-2865
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• 2012

In order to block mobile junk messages automatically, many studies on spam filters have applied machine learning algorithms. Most previous research focused only on the accuracy rate of spam filters from the view point of the algorithm used, not on individual user's preferences. In terms of individual taste, the spam filters implemented on a mobile device have the advantage over spam filters on a network node, because it deals with only incoming messages on the users' phone and generates no additional traffic during the filtering process. However, a spam filter on a mobile phone has to consider the consumption of resources, because energy, memory and computing ability are limited. Moreover, as time passes an increasing number of feature words are likely to exhaust mobile resources. In this paper we propose a spam filter model distributed between a users' computer and smart phone. We expect the model to follow personal decision boundaries and use the uniform resources of smart phones. An authorized user's computer takes on the more complex and time consuming jobs, such as feature selection and training, while the smart phone performs only the minimum amount of work for filtering and utilizes the results of the information calculated on the desktop. Our experiments show that the accuracy of our method is more than 95% with Na$\ddot{i}$ve Bayes and Support Vector Machine, and our model that uses uniform memory does not affect other applications that run on the smart phone.

• 대한화학회지
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• 제55권6호
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• pp.1042-1055
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• 2011

이 연구는 보일의 법칙과 샤를의 법칙에 대한 중학교 1학년 학생들의 인지수준과 배경 요인에 따른 개념 문제 해결력과 수리 문제 해결력을 비교한 것이다. 연구를 위해 개념과 수리 문제 해결력 검사지를 개발하여, 중학생들의 인지수준과 배경 요인에 따른 개념 문제 해결력과 수리 문제 해결력을 비교하고, 기억 보유 효과를 알아보았으며, 어떠한 개념을 가지고 문제를 해결하였는지 분석하였다. 연구 결과, 모든 인지수준에서 개념 문제 해결력이 수리 문제 해결력보다 높았으며, 구체적 조작기와 과도기의 중학생들의 경우 그 차이가 통계적으로 유의미하였다. 개념 문제 해결력과 수리 문제 해결력에 대한 기억 보유 효과 비교에서 형식적 조작기 중학생들은 기억 보유 효과가 있었다. 중학생들의 배경 요인에 따른 개념 문제 해결력과 수리 문제 해결력 비교에서 사교육을 받은 중학생들과 받지 않은 중학생들 사이의 개념 문제 해결력과 수리 문제 해결력에 통계적으로 유의미한 차이는 없었다. 그러나 과학 활동 경험과 과학 관련 진로 희망 여부에서는 과학 활동 경험이 있고 과학 관련 진로를 희망하는 중학생들이 그렇지 않은 중학생들보다 개념 문제 해결력과 수리 문제 해결력이 모두 통계적으로 유의미하게 높았다. 중학생들의 문제 해결 과정을 분석해 본 결과, 거시적인 현상을 단순히 기억하여 과학적 개념에 대한 올바른 이해 없이 문제를 해결하려는 경향이 있었다. 그러므로 중학생들의 비과학적인 개념을 사전에 파악하여 이를 과학적인 개념으로 바꿀 수 있는 교수-학습 전략이 필요하다.

• 한국축산식품학회지
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• 제40권2호
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• pp.183-196
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• 2020

The protective effect of pig skin gelatin water extracts (PSW) and the low molecular weight hydrolysates of PSW generated via enzymatic hydrolysis with Flavourzyme® 1000L (LPSW) against scopolamine-induced impairment of cognitive function in mice was determined. Seventy male ICR mice weighing 20-25 g were randomly assigned to seven groups: Control (CON); scopolamine (SCO, 1 mg/kg B.W., intraperitoneally (i.p.); tetrahydroaminoacridine 10 [THA 10, tacrine; 10 mg/kg B.W. per oral (p.o.) with SCO (i.p.)]; PSW 10 (10 mg/kg B.W. (p.o.) with SCO (i.p.); PSW 40 (40 mg/kg B.W. (p.o.) with SCO (i.p.); LPSW 100 (100 mg/kg B.W. (p.o.) with SCO (i.p.); LPSW 400 (400 mg/kg B.W. (p.o.) with SCO (i.p.). All treatment groups, except CON, received scopolamine on the day of the experiment. The oxygen radical absorbance capacity of LPSW 400 at 1 mg/mL was 154.14 μM Trolox equivalent. Administration of PSW and LPSW for 15 weeks did not significantly affect on physical performance of mice. LPSW 400 significantly increased spontaneous alternation, reaching the level observed for THA and CON. The latency time of animals receiving LPSW 400 was higher than that of mice treated with SCO alone in the passive avoidance test, whereas it was shorter in the water maze test. LPSW 400 increased acetylcholine (ACh) content and decreased ACh esterase activity (p<0.05). LPSW 100 and LPSW 400 reduced monoamine oxidase-B activity. These results indicated that LPSW at 400 mg/kg B.W. is a potentially strong antioxidant and contains novel components for the functional food industry.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권5호
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• pp.1590-1609
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• 2021

Laughter is one of the most important nonverbal sound that human generates. It is a means for expressing his emotions. The acoustic and contextual features of this specific sound are different from those of speech and many difficulties arise during their modeling process. During this work, we propose an audio laughter generation system based on unsupervised generative models: the autoencoder (AE) and its variants. This procedure is the association of three main sub-process, (1) the analysis which consist of extracting the log magnitude spectrogram from the laughter database, (2) the generative models training, (3) the synthesis stage which incorporate the involvement of an intermediate mechanism: the vocoder. To improve the synthesis quality, we suggest two hybrid models (LSTM-VAE, GRU-VAE and CNN-VAE) that combine the representation learning capacity of variational autoencoder (VAE) with the temporal modelling ability of a long short-term memory RNN (LSTM) and the CNN ability to learn invariant features. To figure out the performance of our proposed audio laughter generation process, objective evaluation (RMSE) and a perceptual audio quality test (listening test) were conducted. According to these evaluation metrics, we can show that the GRU-VAE outperforms the other VAE models.

• 문화기술의 융합
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• 제9권3호
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• pp.797-802
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• 2023

영어가 외국어로서 사용되는 환경에서 영어 말하기 연습 활동에 AI 음성 챗봇을 사용했을 때 영어학습자들은 발화 동기가 높아지고 의사소통 연습의 기회가 많아져 결과적으로 영어 말하기 능력을 향상 시킬 수 있다. 본 연구에서는 초등학생 저학년의 경우에도 쉽게 활용 가능하고 학습효과를 높일 수 있는 가르치기 방식의 AI 음성 챗봇을 제안한다. 시제와 맥락과 기억에 기반한 활동인 언어학습에 Teachable Agent 시스템을 적용하기 위해 Teachable Agent에 학습자의 영어 발음과 수준을 반영하고, 학습자 오류에 맞추어 에이전트의 답변을 생성하는 방식을 적용하여 새로운 방식의 TA를 제안하고 이를 적용한 Teachable Agent AI 챗봇 프로토타입을 구현하였다. 실제 초등 영어 선생님과 초등학생을 대상으로 사용성 평가를 진행하여 학습 효과를 입증하였다. 본 연구 결과는 역할 전환을 통해 학습에 흥미가 없는 학생 또는 초등 저학년들이 학습에 스스로 참여할 수 있는 동기부여를 할 수 있도록 적용할 수 있다.

• 한국간호교육학회지
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• 제7권2호
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• pp.360-368
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• 2001

This research was an attempt to find out an entrance experience into major subject of student nurse. The purpose of this study was to understand an lived learning experience of student nurse. Method of the study was applied a phenomenological approach used by Colaizzi's analytic technique. Participants were 33 sophomore student nurse from TC University. The investigator conducted participated observations and in-depth unstructured interviews which were audio taped under the permission of student nurse, formulating meanings, themes and theme clusters. Results of the study were revealed 6 categories, 14 theme clusters, and 31 themes. Six categories include 'feeling anxious about clinical application', 'making superficial class', 'evaluation for ability of memory', 'deficit of academic evaluation criteria', 'insufficiency of textbook' and 'deficit for uniqueness of nursing science'. This findings confirm the fact that the student nurse's entrance experience was complicated and diversely influenced by their learning experiences. In conclusion, this study will prove helpful not only in understanding student nurse's entrance experience about their specialities but also in developing curriculum for nursing education.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권1호
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• pp.39-42
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• 2002

For the purpose of modeling EEG signal which has nonstationary and nonlinear dynamic characteristics, this paper propose a state feedback real time recurrent neural network model. The state feedback real time recurrent neural network is structured to have memory structure in the state of hidden layers so that it has arbitrary dynamics and ability to deal with time-varying input through its own temporal operation. For the model test, Mackey-Glass time series is used as a nonlinear dynamic system and the model is applied to the prediction of three types of EEG, alpha wave, beta wave and epileptic EEG. Experimental results show that the performance of the proposed model is better than that of other neural network models which are compared in this paper in some view points of the converging speed in learning stage and normalized mean square error for the test data set.

• 대한교통학회지
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• 제25권3호
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• pp.87-97
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• 2007

본 연구에서는 기존의 한정합리적인 모델에서 자주 언급된 운전자의 인지의 한계와 정보처리능력의 한계에 초점을 두어 운전자의 경로선택 행동에 대한 모델링과 정보제공에 따른 운전자의 교통환경에 대한 신념(belief) 형성과정을 살펴보기로 한다. 나아가 기존의 운전자의 기대형성 및 경로선택 행동에서 자주 인용된 모델들이 가지는 문제점과 현실에서 도입을 위한 한계점을 지적하고 실제의 도로 네트워크를 가정한 시뮬레이션을 통하여 운전자의 이질 성에 따른 경로선택 행동과 운전자의 도로 환경에 대한 신념 형성의 과정을 모델링 하였다. 본 연구를 통해 도로의 특성 및 운전자 그룹의 특성에 따라 운전자의 학습 과정과 정보의 가치가 달라짐을 확인 할 수 있었다. 먼저 교통량의 증가에 민감하게 도로의 혼잡이 심해지는 환경에서 정보의 효용이 커지는 것을 알 수 있었으며, 운전하는 횟수의 차이에 따라 정보의 가치가 차이가 남을 확인할 수 있었다. 나아가 한정된 교통환경하에서 매일 주행하는 운전자의 비율 차이가 운전자가 형성하게 되는 경로의 특성에 대한 신념의 차이로 이어짐도 확인할 수 있었다.