• Title/Summary/Keyword: long-memory

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Neuropsychology of Memory (기억의 신경심리학)

  • Rhee, Min-Kyu
    • Sleep Medicine and Psychophysiology
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    • v.4 no.1
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    • pp.1-14
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    • 1997
  • This paper reviewed models to explain memory and neuropsychological tests to assess memory. Memory was explained in cognitive and neuroanatomical perspectives, Cognitive model describes memory as structure and process. In structure model, memory is divided into three systems: sensory memory, short-term memory(working memory), and long-term memory. In process model, there are broadly three categories of memory process: encoding, storage, and retrieval. Memory process work in memory structure. There are two prominent models of the neuroanatomy of memory, derived from the work of Mishkin and Appenzeller and that of Squire and Zola-Morgan. These two models are the most useful for the clinician in part because they take into account the connections between the limbic and frontal cortical regions. The major difference between the two models concerns the role of the amygdala in memory processess. Mishkin and his colleagues believe that the amygdala plays a significant role while Squire and his colleagues do not. The most popular and widely used tests of memory ability such as WMS-R, AVLT, CVLT, HVLT. RBMT, CFT, and BVRT-R, were reviewed.

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The Long Term Memory Effects of Virtual Reality Edutainment with HMD (가상현실교육게임의 장기기억효과)

  • Lee, Daeyoung;Lee, Seungje;Jeong, Eui Jun
    • Journal of Korea Game Society
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    • v.18 no.2
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    • pp.69-76
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    • 2018
  • HMD makes big issues about virtual reality in these days. Experience of virtual reality may cause different effects with experience of real world, so this is the reason why comparison studies are needed. There are many works about usefulness of virtual reality education but most of studies were considered as special training. This study was started for the long term memory effect of virtual reality education game. Difference study of memory between real world education game and virtual reality education game shows virtual reality system has smaller diminution of memory than real world. And environment existence was defined as a main effect of long term memory through the test.

Abusive Detection Using Bidirectional Long Short-Term Memory Networks (양방향 장단기 메모리 신경망을 이용한 욕설 검출)

  • Na, In-Seop;Lee, Sin-Woo;Lee, Jae-Hak;Koh, Jin-Gwang
    • The Journal of Bigdata
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    • v.4 no.2
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    • pp.35-45
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    • 2019
  • Recently, the damage with social cost of malicious comments is increasing. In addition to the news of talent committing suicide through the effects of malicious comments. The damage to malicious comments including abusive language and slang is increasing and spreading in various type and forms throughout society. In this paper, we propose a technique for detecting abusive language using a bi-directional long short-term memory neural network model. We collected comments on the web through the web crawler and processed the stopwords on unused words such as English Alphabet or special characters. For the stopwords processed comments, the bidirectional long short-term memory neural network model considering the front word and back word of sentences was used to determine and detect abusive language. In order to use the bi-directional long short-term memory neural network, the detected comments were subjected to morphological analysis and vectorization, and each word was labeled with abusive language. Experimental results showed a performance of 88.79% for a total of 9,288 comments screened and collected.

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Random Walk Test on Hedge Ratios for Stock and Futures (헤지비율의 시계열 안정성 연구)

  • Seol, Byungmoon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.2
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    • pp.15-21
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    • 2014
  • The long memory properties of the hedge ratio for stock and futures have not been systematically investigated by the extant literature. To investigate hedge ratio' long memory, this paper employs a data set including KOSPI200 and S&P500. Coakley, Dollery, and Kellard(2008) employ a data set including a stock index and commodities foreign exchange, and suggested the S&P500 to be a fractionally integrated process. This paper firstly estimates hedge ratios with two dynamic models, BEKK(Bollerslev, Engle, Kroner, and Kraft) and diagonal-BEKK, and tests the long memory of hedge ratios with Geweke and Porter-Hudak(1983)(henceforth GPH) and Lo's modified rescaled adjusted range test by Lo(1991). In empirical results, two hedge ratios based on KOSPI200 and S&P500 show considerably significant long memory behaviours. Thus, such results show the hedge ratios to be stationary and strongly reject the random walk hypothesis on hedge ratios, which violates the efficient market hypothesis.

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Long Memory and Cointegration in Crude Oil Market Dynamics (국제원유시장의 동적 움직임에 내재하는 장기기억 특성과 공적분 관계 연구)

  • Kang, Sang Hoon;Yoon, Seong-Min
    • Environmental and Resource Economics Review
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    • v.19 no.3
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    • pp.485-508
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    • 2010
  • This paper examines the long memory property and investigates cointegration in the dynamics of crude oil markets. For these purposes, we apply the joint ARMA-FIAPARCH model with structural break and the vector error correction model (VECM) to three daily crude oil prices: Brent, Dubai and West Texas Intermediate (WTI). In all crude oil markets, the property of long memory exists in their volatility, and the ARMA-FIAPARCH model adequately captures this long memory property. In addition, the results of the cointegration test and VECM estimation indicate a bi-directional relationship between returns and the conditional variance of crude oil prices. This finding implies that the dynamics of returns affect volatility, and vice versa. These findings can be utilized for improving the understanding of the dynamics of crude oil prices and forecasting market risk for buyers and sellers in crude oil markets.

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Prediction of time-series underwater noise data using long short term memory model (Long short term memory 모델을 이용한 시계열 수중 소음 데이터 예측)

  • Hyesun Lee;Wooyoung Hong;Kookhyun Kim;Keunhwa Lee
    • The Journal of the Acoustical Society of Korea
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    • v.42 no.4
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    • pp.313-319
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    • 2023
  • In this paper, a time series machine learning model, Long Short Term Memory (LSTM), is applied into the bubble flow noise data and the underwater projectile launch noise data to predict missing values of time-series underwater noise data. The former is mixed with bubble noise, flow noise, and fluid-induced interaction noise measured in a pipe and can be classified into three types. The latter is the noise generated when an underwater projectile is ejected from a launch tube and has a characteristic of instantaenous noise. For such types of noise, a data-driven model can be more useful than an analytical model. We constructed an LSTM model with given data and evaluated the model's performance based on the number of hidden units, the number of input sequences, and the decimation factor of signal. It is shown that the optimal LSTM model works well for new data of the same type.

ON ALMOST SURE REPRESENTATIONS FOR LONG MEMORY SEQUENCES

  • Ho, Hwai-Chung
    • Journal of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.741-753
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    • 1998
  • Let G(*) be a Borel function applied to a stationary long memory sequence {X$_{i}$} of standard Gaussian random variables. Focusing on the process {G(X$_{i}$)}, the present paper establishes the almost sure representation for the empirical quantile process, that is, Bahadur's representation, and for the empirical process with respect to sample mean. Statistical applications of the representations are also addressed.sed.

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Global Warming Trend : Further Evidence from Multivariate Long Memory Models of Temperature and Tree Ring Series

  • Chung, Sang-Kuck
    • Environmental and Resource Economics Review
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    • v.9 no.3
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    • pp.515-544
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    • 2000
  • This paper shows that various fractionally integrated univariate and multivariate are remarkably successful in representing annual temperature series and also very long series of tree ring widths, which are often used as a proxy for temperature. The analysis also suggests that human recorded temperature series are not inconsistent with being generated by a stationary, long memory process. From the empirical results, we should be noted that the statistically significant positive trend coefficients may well be due to small sample sizes. These results cast some doubt on the basic assumption that global warming is definitely occurring.

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The Improvement of Short- and Long-term Memory of Young Children by BF-7 (천연 소재 BF-7의 어린이 장.단기 기억력 향상 효과)

  • Kim, Do-Hee;Kim, Ok-Hyeon;Yeo, Joo-Hong;Lee, Kwang-Gill;Park, Geum-Duck;Kim, Dae-Jin;Chung, Yoon-Hee;Kim, Kyung-Yong;Lee, Won-Bok;Youn, Young-Chul;Chung, Yoon-Hwa;Lee, Sang-Hyung;Hyun, Joo-Seok
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.3
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    • pp.376-382
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    • 2010
  • It has been shown that BF-7 enhances short- and long-term memory and attention in normal person. BF-7 was addressed to clinical study for children if BF-7 is also effective to children, since accumulated verification of safety and effectiveness is needed for young ages, in special. We administered BF-7 and a placebo control to two different groups of children (7-12 years old, 9.78 on averages). Their memory enhancement was tested with Rey-Kim Memory Test for Children before and after the administration of BF-7 and a placebo, in a double blinded way. The results showed that long- and short-term memories were significantly improved by the administration of BF-7. Interestingly, the degree of memory preservation, the ability of memory application and awareness of complex thing were also significantly improved. These results indicate that BF-7 is a promising substance from natural resource improving learning and memory of children as well as cognitive function of adults

Effects of Selective Serotonin Reuptake Inhibitors on the Retention of Passive Avoidance Learning after Chronic Mild Stress in Rats (선택적 세로토닌 재흡수차단제들이 만성 경도 스트레스 후의 백서에서 수동적 회피학습에 미치는 영향)

  • Lee, Gi-Chul;Chang, Hwan-Il
    • Korean Journal of Biological Psychiatry
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    • v.4 no.2
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    • pp.237-245
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    • 1997
  • The study was designed to evaluate the significant roles of SSRI in rat of depression model. Chronic exposure to mild unpredictable stress has been found to depress the consumption of sweet 1% sucrose solutions in the Sprague-Dawley rats. We applied the variety of 11 types of stress regimens and identified depressive behaviours(developed by Willner) in 70 Sprague-Dawley rats. Rats in experiments were stratified into 6 groups, ie ; 3 kinds of SSRI(paroxetine, fluoxetine, sertraline), clomipramine, choline and saline control. Memory function was evaluated by passive avoidance learning and retention test. The authors determined how long memory retention would remain improved with 24 hour, 1 week, 2 weeks, 3 weeks, and 4 weeks at training-testing interval in depressive states of the Sprague-Dawley rats. The results were as follows ; 1) There were no significant differences between the 6 groups at the 24 hour training-testing interval. 2) The paroxetine treated group showed significant differences from the control group at the 1 week and 2 weeks training-testing interval. 3) The paroxetine and the fluoxetine treated groups showed singificant differences from the control group at 3 week training-testing interval. 4) The paroxetine and the choline treated groups showed significant differences from the control group at 4 week training-testing interval. In summary, paroxetine had an effect on long term memory processing from 1st week to 4th week. Also, fluoxetine(at 3rd week) and choline(at 4th week) had effect on long term memory processing. Sertraline, clomipramine were ineffective on memory processing during 4 weeks observation. Possible explanations why paroxetine had early effect on memory processing than the other selective serotonin reuptake inhibitors are rapid bioavailability, which is the characteristics of pharmacokinetics of paroxetine. In clinical situation, author carefully suggest that SSRI would be beneficial to improve the memory function caused by depressive neurochemical changes.

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