• Title/Summary/Keyword: Long-Term Memory

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Does the Gut Microbiota Regulate a Cognitive Function? (장내미생물과 인지기능은 서로 연관되어 있는가?)

  • Choi, Jeonghyun;Jin, Yunho;Kim, Joo-Heon;Hong, Yonggeun
    • Journal of Life Science
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    • v.29 no.6
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    • pp.747-753
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    • 2019
  • Cognitive decline is characterized by reduced long-/short-term memory and attention span, and increased depression and anxiety. Such decline is associated with various degenerative brain disorders, especially Alzheimer's disease (AD) and Parkinson's disease (PD). The increases in elderly populations suffering from cognitive decline create social problems and impose economic burdens, and also pose safety threats; all of these problems have been extensively researched over the past several decades. Possible causes of cognitive decline include metabolic and hormone imbalance, infection, medication abuse, and neuronal changes associated with aging. However, no treatment for cognitive decline is available. In neurodegenerative diseases, changes in the gut microbiota and gut metabolites can alter molecular expression and neurobehavioral symptoms. Changes in the gut microbiota affect memory loss in AD via the downregulation of NMDA receptor expression and increased glutamate levels. Furthermore, the use of probiotics resulted in neurological improvement in an AD model. PD and gut microbiota dysbiosis are linked directly. This interrelationship affected the development of constipation, a secondary symptom in PD. In a PD model, the administration of probiotics prevented neuron death by increasing butyrate levels. Dysfunction of the blood-brain barrier (BBB) has been identified in AD and PD. Increased BBB permeability is also associated with gut microbiota dysbiosis, which led to the destruction of microtubules via systemic inflammation. Notably, metabolites of the gut microbiota may trigger either the development or attenuation of neurodegenerative disease. Here, we discuss the correlation between cognitive decline and the gut microbiota.

Does Brand Experience Affect Consumer's Emotional Attachments? (브랜드의 총체적 체험이 소비자-브랜드의 정서적 유대관계에 미치는 영향)

  • Lee, Jieun;Jeon, Jooeon;Yoon, Jaeyoung
    • Asia Marketing Journal
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    • v.12 no.2
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    • pp.53-81
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    • 2010
  • Brand experience has received much attention from considerable marketing research. When consumers consume and use brands, they are exposed to various specific brand-related stimuli. These brand-related stimuli include brand identity and brand communications(e.g., colors, shapes, designs, slogans, mascots, brand characters) components. Brakus, Schmitt, and Zarantonello(2009) conceptualized brand experience as subjective and internal consumer responses evoked by brand-related stimuli. They demonstrated that brand experience can be broken down into four dimensions(sensory, affective, intellectual, and behavioral). Because experiences result from stimulations and lead to pleasurable outcomes, we expect consumers to want to repeat theses experiences. That is, brand experiences, stored in consumer memory, should affect brand loyalty. Consumers with positive experiences should be more likely to buy a brand again and less likely to buy an alternative brand(Fournier 1998; Oliver 1997). Brand attachment, one of dimensions of the consumer-brand relationship, is defined as an emotional bond to the specific brand(Thomson, MacInnis, and Park 2005). Brand attachment is target-specific bond between the consumer and the specific brand. Thus, strong attachment is attended by a rich set of schema that link the brand to the consumer. Previous researches propose that brand attachments should affect consumers' commitment to the brand. Brand experience differs from affective construct such as brand attachment. Brand attachment is based on interaction between a consumer and the brand. In contrast, brand experience occurs whenever there is a direct and indirect interaction with the brand. Furthermore, brand experience is not an emotional relationship concept. Brakus et al.(2009) suggest that brand experience may result in brand attachment. This study aims to distinguish brand experience dimensions and investigate the effects of brand experience on brand attachment and brand commitment. We test research problems with data from 265 customers having brand experiences in various product categories by using multiple regression and structural equation model. The empirical results can be summarized as follows. First, the paths from affective, behavior, and intellectual experience to the brand attachment were found to be positively significant whereas the effect of sensory experience to brand attachment was not supported. In the consumer literature, sensory experiences for consumers are often equated with aesthetic pleasure. Over time, these pleasure experiences can affect consumer satisfaction. However, sensory pleasures are not linked to attachment such as consumers' strong emotional bond(i.e., hot affect). These empirical results confirms the results of previous studies. Second, brand attachment including passion and connection influences brand commitment positively but affection does not influence brand commitment. In marketing context, consumers with brand attachment have intention to have a willingness to stay with the relationship. The results also imply that consumers' emotional attachment is characterized by a set of brand experience dimensions and consumers who are emotionally attached to the brand are committed. The findings of this research contribute to develop differences between brand experience and brand attachment and to provide practical implications on the brand experience management. Recently, many brand managers have focused on short-term view. According to this study, we suggest that effective brand experience management requires taking a long-term view of marketing decisions.

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Development of Deep-Learning-Based Models for Predicting Groundwater Levels in the Middle-Jeju Watershed, Jeju Island (딥러닝 기법을 이용한 제주도 중제주수역 지하수위 예측 모델개발)

  • Park, Jaesung;Jeong, Jiho;Jeong, Jina;Kim, Ki-Hong;Shin, Jaehyeon;Lee, Dongyeop;Jeong, Saebom
    • The Journal of Engineering Geology
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    • v.32 no.4
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    • pp.697-723
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    • 2022
  • Data-driven models to predict groundwater levels 30 days in advance were developed for 12 groundwater monitoring stations in the middle-Jeju watershed, Jeju Island. Stacked long short-term memory (stacked-LSTM), a deep learning technique suitable for time series forecasting, was used for model development. Daily time series data from 2001 to 2022 for precipitation, groundwater usage amount, and groundwater level were considered. Various models were proposed that used different combinations of the input data types and varying lengths of previous time series data for each input variable. A general procedure for deep-learning-based model development is suggested based on consideration of the comparative validation results of the tested models. A model using precipitation, groundwater usage amount, and previous groundwater level data as input variables outperformed any model neglecting one or more of these data categories. Using extended sequences of these past data improved the predictions, possibly owing to the long delay time between precipitation and groundwater recharge, which results from the deep groundwater level in Jeju Island. However, limiting the range of considered groundwater usage data that significantly affected the groundwater level fluctuation (rather than using all the groundwater usage data) improved the performance of the predictive model. The developed models can predict the future groundwater level based on the current amount of precipitation and groundwater use. Therefore, the models provide information on the soundness of the aquifer system, which will help to prepare management plans to maintain appropriate groundwater quantities.

Development of a complex failure prediction system using Hierarchical Attention Network (Hierarchical Attention Network를 이용한 복합 장애 발생 예측 시스템 개발)

  • Park, Youngchan;An, Sangjun;Kim, Mintae;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.127-148
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    • 2020
  • The data center is a physical environment facility for accommodating computer systems and related components, and is an essential foundation technology for next-generation core industries such as big data, smart factories, wearables, and smart homes. In particular, with the growth of cloud computing, the proportional expansion of the data center infrastructure is inevitable. Monitoring the health of these data center facilities is a way to maintain and manage the system and prevent failure. If a failure occurs in some elements of the facility, it may affect not only the relevant equipment but also other connected equipment, and may cause enormous damage. In particular, IT facilities are irregular due to interdependence and it is difficult to know the cause. In the previous study predicting failure in data center, failure was predicted by looking at a single server as a single state without assuming that the devices were mixed. Therefore, in this study, data center failures were classified into failures occurring inside the server (Outage A) and failures occurring outside the server (Outage B), and focused on analyzing complex failures occurring within the server. Server external failures include power, cooling, user errors, etc. Since such failures can be prevented in the early stages of data center facility construction, various solutions are being developed. On the other hand, the cause of the failure occurring in the server is difficult to determine, and adequate prevention has not yet been achieved. In particular, this is the reason why server failures do not occur singularly, cause other server failures, or receive something that causes failures from other servers. In other words, while the existing studies assumed that it was a single server that did not affect the servers and analyzed the failure, in this study, the failure occurred on the assumption that it had an effect between servers. In order to define the complex failure situation in the data center, failure history data for each equipment existing in the data center was used. There are four major failures considered in this study: Network Node Down, Server Down, Windows Activation Services Down, and Database Management System Service Down. The failures that occur for each device are sorted in chronological order, and when a failure occurs in a specific equipment, if a failure occurs in a specific equipment within 5 minutes from the time of occurrence, it is defined that the failure occurs simultaneously. After configuring the sequence for the devices that have failed at the same time, 5 devices that frequently occur simultaneously within the configured sequence were selected, and the case where the selected devices failed at the same time was confirmed through visualization. Since the server resource information collected for failure analysis is in units of time series and has flow, we used Long Short-term Memory (LSTM), a deep learning algorithm that can predict the next state through the previous state. In addition, unlike a single server, the Hierarchical Attention Network deep learning model structure was used in consideration of the fact that the level of multiple failures for each server is different. This algorithm is a method of increasing the prediction accuracy by giving weight to the server as the impact on the failure increases. The study began with defining the type of failure and selecting the analysis target. In the first experiment, the same collected data was assumed as a single server state and a multiple server state, and compared and analyzed. The second experiment improved the prediction accuracy in the case of a complex server by optimizing each server threshold. In the first experiment, which assumed each of a single server and multiple servers, in the case of a single server, it was predicted that three of the five servers did not have a failure even though the actual failure occurred. However, assuming multiple servers, all five servers were predicted to have failed. As a result of the experiment, the hypothesis that there is an effect between servers is proven. As a result of this study, it was confirmed that the prediction performance was superior when the multiple servers were assumed than when the single server was assumed. In particular, applying the Hierarchical Attention Network algorithm, assuming that the effects of each server will be different, played a role in improving the analysis effect. In addition, by applying a different threshold for each server, the prediction accuracy could be improved. This study showed that failures that are difficult to determine the cause can be predicted through historical data, and a model that can predict failures occurring in servers in data centers is presented. It is expected that the occurrence of disability can be prevented in advance using the results of this study.

Improving Bidirectional LSTM-CRF model Of Sequence Tagging by using Ontology knowledge based feature (온톨로지 지식 기반 특성치를 활용한 Bidirectional LSTM-CRF 모델의 시퀀스 태깅 성능 향상에 관한 연구)

  • Jin, Seunghee;Jang, Heewon;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.24 no.1
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    • pp.253-266
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    • 2018
  • This paper proposes a methodology applying sequence tagging methodology to improve the performance of NER(Named Entity Recognition) used in QA system. In order to retrieve the correct answers stored in the database, it is necessary to switch the user's query into a language of the database such as SQL(Structured Query Language). Then, the computer can recognize the language of the user. This is the process of identifying the class or data name contained in the database. The method of retrieving the words contained in the query in the existing database and recognizing the object does not identify the homophone and the word phrases because it does not consider the context of the user's query. If there are multiple search results, all of them are returned as a result, so there can be many interpretations on the query and the time complexity for the calculation becomes large. To overcome these, this study aims to solve this problem by reflecting the contextual meaning of the query using Bidirectional LSTM-CRF. Also we tried to solve the disadvantages of the neural network model which can't identify the untrained words by using ontology knowledge based feature. Experiments were conducted on the ontology knowledge base of music domain and the performance was evaluated. In order to accurately evaluate the performance of the L-Bidirectional LSTM-CRF proposed in this study, we experimented with converting the words included in the learned query into untrained words in order to test whether the words were included in the database but correctly identified the untrained words. As a result, it was possible to recognize objects considering the context and can recognize the untrained words without re-training the L-Bidirectional LSTM-CRF mode, and it is confirmed that the performance of the object recognition as a whole is improved.

Effect of Acupuncture on Nasal Obstruction in Patients with Persistent Allergic Rhinitis: A Randomized Controlled Trial (지속성 알레르기비염의 비폐색에 대한 침치료의 효과: 무작위배정 대조군 연구)

  • Jo, Jeong-Hyo;Hong, Kweon-Eey;Kang, Wee-Chang;Choi, Sun-Mi;Park, Yang-Chun
    • Journal of Acupuncture Research
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    • v.22 no.6
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    • pp.229-239
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    • 2005
  • Objectives : Allergic rhinitis is a prevalent disease. Nasal obstruction is one of the main symptom in allergic rhinitis. It induces sleep disturbances, depression, attention deficit, memory impairments. Acupuncture treatment for rhinitis was mentioned in literature, but there is not enough report that provide evidence by well designed clinical study. The purpose of this research is to examine the effect of acupuncture treatment for nasal obstruction of allergic rhinitis. Methods : In this randomized, single blind, placebo-controlled study, we compared active acupuncture with minimal acupuncture for the treatment of nasal obstruction owing to persistent allergic rhinitis. Acupoints used in active acupuncture group were I120($Y{\hat{o}}nghyang$), GV23($Sangs{\hat{o}}ng$), IL4(Hapkok). Volunteers who satisfied the requirements were enrolled in study. Total nasal volume(NV) and total nasal minimum cross-sectional area(MCA) were measured by acoustic rhinometry before and after treatments(0min, 7.5min, 15min). Results : 101 subjects finished study. There were not difference between two groups on age, sex, weight, height, blood pressure, pulse, respiratory rate, severity of persistent allergic rhinitis, number of positive antigen. After treatment(0min) total NV were significantly increased compared with before treatment in active acupuncture group(p=0.0007) and minimal acupuncture group(p=0.0175). After treatment(15min) total NV of minimal acupuncture group was decreased compared with before treatment(p=0.2560), but total NV of active acupuncture group was maintained increasing in degree of borderline significance(p=0.0871). After treatment(0min) total NV were significantly increased compared with before treatment in active acupuncture group(0.0007) and minimal acupuncture group(p=0.0175). After treatment(Omin) total MCA were significantly increased compared with before treatment in active acupuncture group(p<0.000l) and minimal acupuncture group(p=0.0005). After treatment(15min) total MCA of minimal acupuncture group was decreased compared with before treatment(p=0.6082), but total NV of active acupuncture group was maintained increasing in degree of borderline significance(p=0.0929). Conclusion : Acupuncture treatment reduced nasal obstruction in persistent allergic rhinitis. Further study in the form of long term is needed.

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Immunohistochemical Expression of Nuclear Retinoid Receptor and CREB(cAMP Response Element Binding Protein) in Lung Cancers (폐암종에서 Nuclear Retinoid Receptor 및 CREB의 면역조직화학적 발현 양상)

  • Shin, Jong Wook;Gi, Seung-Seok;Paik, Kwang Hyun;Choi, Won;Park, In Won;Kim, Mi Kyung
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.6
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    • pp.631-637
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    • 2005
  • Background : Transcriptional factors of the CREB(cAMP Response Element Binding Protein) are involved in the regulation of gene expression in response to a variety of signaling pathways. Proteins produced by the CREB genes play key roles in many physiological processes, including memory and long-term potentiation. The retinoic acid receptor (RAR) axis mediates epithelial cell differentiation and proliferation in many tissues including the lung. Material and method : The RAR and CREB expression levels were examined in 60 adenocarcinomas and 60 squamous cell carcinomas of the lung using immunohistochemical staining. Results : 1) RAR protein expression was found in 58.3%(35/60) of adenocarcinomas and 36.7%(22/60) of squamous cell carcinomas(P<0.05). 2) RAR protein expression was found in 80%(16/20) of well differentiated adenocarcinomas, 60%(12/20) of moderately differentiated adenocarcinomas, and 35%(7/20) of poorly differentiated adenocarcinomas (P<0.01). 3) RAR protein expression was found in 45%(9/20) of well differentiated squamous cell carcinomas, 35%(7/20) of moderately differentiated squamous cell carcinomas, and 30%(6/20) of poorly differentiated squamous cell carcinomas (P>0.05). 4) CREB expression was found in 61.7%(37/60) of adenocarcinomas and 40%(24/60) of squamous cell carcinomas( P<0.05). 5) CREB expression was found in 85%(17/20) of well differentiated adenocarcinomas, 60%(12/20) of moderately differentiated adenocarcinomas, and 40%(8/20) of poorly differentiated adenocarcinomas (P<0.01). 6) CREB expression was found in 45%(9/20) of well differentiated squamous cell carcinomas, 35%(7/20) of moderately differentiated squamous cell carcinomas, and 35%(8/20) of poorly differentiated squamous cell carcinomas(P>0.05). 7) RAR and CREB expression was found in 68.5% of lung cancers, and there was a significant correlation between them(P<0.05). Conclusion : RAR and CREB expression can be used to indirectly determine the malignant potentiality of a cell.

The Immunohistochemical Expression of Nuclear Retinoid Receptor and CREB in Gastric Adenocarcinoma (위선암종에서 핵의 Retinoic Acid Receptor (RAR) 및 cAMP Response Element Binding Protein (CREB)의 면역조직화학적 발현양상)

  • Han, Ho-Sun;Kim, Yong-Seok;Park, Joong-Min;Choi, Yoo-Shin;Cha, Seong-Jae;Kim, Mi-Kyung;Chi, Kyung-Choun
    • Journal of Gastric Cancer
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    • v.8 no.4
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    • pp.182-188
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    • 2008
  • Purpose: Transcriptional factors of CREB (cAMP response element binding protein) are involved in regulating the gene expression in response to a variety of signaling pathways. The proteins produced by the CREB genes play key roles in many physiological processes, including memory and long-term potentiation. The retinoic acid receptor (RAR) axis mediates epithelial cell differentiation and proliferation in many tissues. This study examined the expressions of RAR and CREB and their relationship with the clinicopathologic factors and their significance. Materials and Methods: The levels of the RAR and CREB expressions were measured in 150 gastric adenocarcinomas by performing immunohistochemical staining. Results: 1. An RAR protein expression was found in 63.3% of the adenocarcinomas (95/150) and a CREB expression was found in 60.7% (91/150) of the adenocarcinomas. 2. An RAR protein expression was found in 72.2% (78/108) of the intestinal type adenocarcinomas and in 40.5% (17/42) of the diffuse type adenocarcinomas (P<0.05). Based on the depth of invasion, an RAR protein expression was found in 58.3% (14/24) of the T1 adenocarcinomas, in 61.9% (13/21) of the T2 adenocarcinomas, in 63.5% (61/96) of the T3 adenocarcinomas, in 77.8% (7/9) of the T4 adenocarcinomas and in 74.7% (62/83) of the adenocarcinomas with lymph node metastasis and in 49.2% (33/67) of the adenocarcinomas without lymph node metastasis (P<0.01). 3. A CREB expression was found in 69.4% (75/108) of the intestinal type and in 38.1% (16/42) of the diffuse type (P>0.05). Based on the depth of invasion, a CREB expression was found in 50% (12/24) of the T1 adenocarcinomas, in 52.4% (11/21) of the T2 adenocarcinomas, in 64.6% (62/96) of the T3 adenocarcinomas, in 66.6% (6/9) of the T4 adenocarcinomas, in 71.1% (59/83) of the adenocarcinomas with lymph node metastasis and in 47.8% (32/67) of the adenocarcinomas without lymph node metastasis (P<0.01). 4. The RAR protein and CREB expressions coincided in 71.4% of the gastric adenocarcinomas and a significant correlation between them was found (P<0.05). Conclusion: We found a significant relationship between the expression of RAR and CREB and the histology and lymph node metastasis of gastric cancer. Further studies are needed to confirm their biologic meaning in gastric carcinogenesis.

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Data collection strategy for building rainfall-runoff LSTM model predicting daily runoff (강수-일유출량 추정 LSTM 모형의 구축을 위한 자료 수집 방안)

  • Kim, Dongkyun;Kang, Seokkoo
    • Journal of Korea Water Resources Association
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    • v.54 no.10
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    • pp.795-805
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    • 2021
  • In this study, after developing an LSTM-based deep learning model for estimating daily runoff in the Soyang River Dam basin, the accuracy of the model for various combinations of model structure and input data was investigated. A model was built based on the database consisting of average daily precipitation, average daily temperature, average daily wind speed (input up to here), and daily average flow rate (output) during the first 12 years (1997.1.1-2008.12.31). The Nash-Sutcliffe Model Efficiency Coefficient (NSE) and RMSE were examined for validation using the flow discharge data of the later 12 years (2009.1.1-2020.12.31). The combination that showed the highest accuracy was the case in which all possible input data (12 years of daily precipitation, weather temperature, wind speed) were used on the LSTM model structure with 64 hidden units. The NSE and RMSE of the verification period were 0.862 and 76.8 m3/s, respectively. When the number of hidden units of LSTM exceeds 500, the performance degradation of the model due to overfitting begins to appear, and when the number of hidden units exceeds 1000, the overfitting problem becomes prominent. A model with very high performance (NSE=0.8~0.84) could be obtained when only 12 years of daily precipitation was used for model training. A model with reasonably high performance (NSE=0.63-0.85) when only one year of input data was used for model training. In particular, an accurate model (NSE=0.85) could be obtained if the one year of training data contains a wide magnitude of flow events such as extreme flow and droughts as well as normal events. If the training data includes both the normal and extreme flow rates, input data that is longer than 5 years did not significantly improve the model performance.

Comparative analysis of activation functions of artificial neural network for prediction of optimal groundwater level in the middle mountainous area of Pyoseon watershed in Jeju Island (제주도 표선유역 중산간지역의 최적 지하수위 예측을 위한 인공신경망의 활성화함수 비교분석)

  • Shin, Mun-Ju;Kim, Jin-Woo;Moon, Duk-Chul;Lee, Jeong-Han;Kang, Kyung Goo
    • Journal of Korea Water Resources Association
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    • v.54 no.spc1
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    • pp.1143-1154
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    • 2021
  • The selection of activation function has a great influence on the groundwater level prediction performance of artificial neural network (ANN) model. In this study, five activation functions were applied to ANN model for two groundwater level observation wells in the middle mountainous area of the Pyoseon watershed in Jeju Island. The results of the prediction of the groundwater level were compared and analyzed, and the optimal activation function was derived. In addition, the results of LSTM model, which is a widely used recurrent neural network model, were compared and analyzed with the results of the ANN models with each activation function. As a result, ELU and Leaky ReLU functions were derived as the optimal activation functions for the prediction of the groundwater level for observation well with relatively large fluctuations in groundwater level and for observation well with relatively small fluctuations, respectively. On the other hand, sigmoid function had the lowest predictive performance among the five activation functions for training period, and produced inappropriate results in peak and lowest groundwater level prediction. The ANN-ELU and ANN-Leaky ReLU models showed groundwater level prediction performance comparable to that of the LSTM model, and thus had sufficient potential for application. The methods and results of this study can be usefully used in other studies.