Level Shifts and Long-term Memory in Stock Distribution Markets 주식유통시장의 층위이동과 장기기억과정

정진택 한국유통과학회 2016 유통과학연구 Vol.14 No.1

Purpose – The purpose of paper is studying the static and dynamic side for long-term memory storage properties, and increase the explanatory power regarding the long-term memory process by looking at the long-term storage attributes, Korea Composite Stock Price Index. The reason for the use of GPH statistic is to derive the modified statistic Korea's stock market, and to research a process of long-term memory. Research design, data, and methodology – Level shifts were subjected to be an empirical analysis by applying the GPH method. It has been modified by taking into account the daily log return of the Korea Composite Stock Price Index a. The Data, used for the stock market to analyze whether deciding the action by the long-term memory process, yield daily stock price index of the Korea Composite Stock Price Index and the rate of return a log. The studies were proceeded with long-term memory and long-term semiparametric method in deriving the long-term memory estimators. Chapter 2 examines the leading research, and Chapter 3 describes the long-term memory processes and estimation methods. GPH statistics induced modifications of statistics and discussed Whittle statistic. Chapter 4 used Korea Composite Stock Price Index to estimate the long-term memory process parameters. Chapter 6 presents the conclusions and implications. Results – If the price of the time series is generated by the abnormal process, it may be located in long-term memory by a time series. However, test results by price fixed GPH method is not followed by long-term memory process or fractional differential process. In the case of the time-series level shift, the present test method for a long-term memory processes has a considerable amount of bias, and there exists a structural change in the stock distribution market. This structural change has implications in level shift. Stratum level shift assays are not considered as shifted strata. They exist distinctly in the stock secondary market as bias, and are presented in the test statistic of non-long-term memory process. It also generates an error as a long-term memory that could lead to false results. Conclusions – Changes in long-term memory characteristics associated with level shift present the following two suggestions. One, if any impact outside is flowed for a long period of time, we can know that the long-term memory processes have characteristic of the average return gradually. When the investor makes an investment, the same reasoning applies to him in the light of the characteristics of the long-term memory. It is suggested that when investors make decisions on investment, it is necessary to consider the characters of the long-term storage in reference with causing investors to increase the uncertainty and potential. The other one is the thing which must be considered variously according to time-series. The research for price-earnings ratio and investment risk should be composed of the long-term memory characters, and it would have more predictability.

논문 : 장단기 시장이자율의 장기기억에 관한 연구

이창호 ( Chang Ho Lee ),김종선 ( Chong Sun Kim ) 명지대학교 금융지식연구소 2012 금융지식연구 Vol.10 No.3

본 연구의 ARFIMA(p,d,q) 모형을 이용한 실증분석 결과는 다음과 같다. 첫째로 자기상관계수의 추정결과, 단기금리인 콜금리의 장기기억현상은 존재하였으나, 장 기금리인 국고채3년 및 회사채3년 금리에는 단위근 현상이 존재함으로써 과거의 충격이 지속되는 것으로 분석되었다. 둘째로 단기금리의 경우, 콜금리의 장기기억현상이 존재하는 것으로 분석되었으며, 글로벌금융위기가 포함된 일별콜금리의 제2기의 장기기억현상이 글로벌금융위기 이전의 제1기의 장기기억현상보다 상대적으로 강하게 나타났다. 셋째로 장기금리의 경우, 국고채3년 및 회사채3년 금리에는 대체로 단위근현상이 나타나서 장기기억현상이 존재하지 않았다. The main object of this study is to analyse the long memory effect of long-term & short-term interest rates in the point of market efficiency. Accordingly, this study focuses on analysing the ARFIMA model which detect the long memory effect of long-term(3 years-corporate bond rate & 3 years-government bond rate) and short-term(call rate) interest rates. Some empirical results are summarized as follows ; Firstly, contrary to the case of long-term interest rate, a long memory of the short-term interest rate was found in terms of autocorrelation coefficients & partial autocorrelation coefficients. Secondly, the long memory of short-term interest rate was found, and the long memory effect of the first period(2000.1∼2008.6) was stronger than that of the second period(2008.7∼2012.10). Thirdly, the long memory of long-term interest rate was not found, and the results showed the unit root process. Therefore, the market efficiency hypothesis was rejected by these results in case of short-term interest & long-term interest in Korean financial market.

기간프리미엄의 장기기억현상

정수관(SuKwan Jung),원두환(DooHwan Won) 한국경제통상학회 2016 경제연구 Vol.34 No.4

시계열의 적분차수를 정수로 한정하는 전통적인 단위근 및 공적분 방법의 한계를 고려하여 본 연구는 장단기이자율과 기간프리미엄의 장기기억을 검토하였다. 실제 단기이자율과 ARFIMA 모형, ARIMA 모형의 예측치는 기대단기이자율의 대리변수로, 장기이자율과 기대 단기이자율 간 차이는 기간프리미엄으로 사용되었다. 구조변화 시점을 추정하고, 구조변화 전후 기간을 나누어 장기기억현상이 분석되었다. 분석 결과 ARFIMA모형은 구조변화와 상관없이 이자율과 기간프리미엄의 장기기억현상을 일관성 있지만, 준모수적 방법은 ARFIMA모형보다 차분계수를 과대평가하거나 구조변화에 민감하였다. ARFIMA모형이 준모수적 방법보다 강건하다는 점을 고려한다면 이자율과 기간프리미엄에 장기기억이 존재할 가능성이 높다. This study examined long memory of short-term and long-term interest rates and term premiums in Korea. Standard unit root test methods or co-integration analysis was restricted to an integer, so these methods did not determine fractional integration of time series. In contrast, fractional integral methods allowed any real number of integration to find out long memory. Actual short-term interest rate and prediction of short-term interest rates from ARFIMA and ARIMA models were utilized as proxy variables for the expected short-term interest rates. The term premium was calculated from the difference between long-term interest rates and the expected short-term interest rates. The results show that ARFIMA models provided long-memory of interest rates and term-premium while semi-fractional integration method did not. The semi-parametric method overestimated the long-memory parameter compared with the ARFIMA model. The estimates of semi-parametric method were also sensitive to structural changes. The effects of shocks may remain long period. It is necessary to consider long-memory of interest rates and term premiums.

기억의 신경생물학적 기전

정영인,이영민,문은수 대한노인정신의학회 2016 노인정신의학 Vol.20 No.1

Memory is one of the most important mental mechanisms which is crucial for us to adapt to environmental surroundings and to maintain our identity. The neurobiological mechanisms for memory are based upon the synaptic plasticity that involve both functional and structural changes at the synapses in the neural circuits participating in learning and memory. Memory is not a single process but has two forms of short-term and long-term memory that are two independent but overlapping processes that blend into one another. The short-term memory depends upon the functional change of synaptic strength but the long-term memory requires anatomic changes of synapses in the neural circuit. Memory storage seems to use elements of a common genetic switch, involving cyclic adenosine monophospate (cAMP)-dependent protein kinase, mitogen activated protein kinase, and cAMP response elementbinding protein, to convert short-term memory into long-term memory.

빛의 조도와 기억 망각 간의 관계성에 대한 예비연구

이충원,김진호,김보성 한국감성과학회 2022 춘계학술대회 Vol.2022 No.-

A series of studies dealing with light and memory argue that the effects of light on human attention, working memory, and long-term memory may be different depending on the characteristics of light. In particular, in terms of light illuminance, it is reported that attention and working memory performance is excellent at a relatively high illuminance of 1,000 lx or higher, while long-term memory performance is excellent at a relatively low illuminance of 400 lx. However, there are only speculations as to why the difference between working memory and long-term memory occurs depending on the illuminance of light, but the exact cause is still unknown. Therefore, this study aims to preliminarily explore the relationship between illuminance and memory forgetfulness as part of the investigation of the cause of the effect of illuminance on memory. If the speed of memory forgetting is different according to the illumination, it may be possible to explain why the performance of long-term memory is excellent at 400 lx. For this purpose, this study was conducted to investigate the effects of each illumination condition on forgetting by measuring the amount of memory wastes after 5 minutes and 30 minutes after the illumination condition was treated at 400 lx and 1,000 lx.

Improvement of Attention, Long-term and Short-term Memory by Brain Factor-7™ (BF-7™)

Hong Junkee,노유훈,이지원,Whang Wan Kyunn,Zheng Yulong,원무호,Kang Il-Jun,김성수 건강기능식품미래포럼 2022 건강기능식품미래포럼 학술지 Vol.2 No.1

Brain Factor-7™ (BF-7™) is a mixture of silk peptides obtained from hydrolyzed fibroin of the cocoon shell of Bombyx mori, which was developed by Famenity Co., LTD and approved as a health functional food by The Korea Ministry of Food and Drug safety. Several previous clinical studies showed that BF-7™ enhanced the learning and cognitive function in various age groups. In the present study, a clinical study was performed to assess whether BF-7™ enhances short-term, long-term memory and attention on 28 college students who were given 400 mg of BF-7™ orally once a day for 4 weeks. The memory was evaluated by Korean version of Memory Assessment Scales (K-MAS) and attention was by encephalogram of P300 wave. The results were as follows. Short-term verbal memory, short-term visual memory, long-term verbal memory and long-term word memory improved by 47.2, 42.2, 54.8 and 22.3%, respectively. The encephalogram of P300 wave showed that the attention level was enhanced significantly but with less stress. In the in vitro studies on SHSY-5Y cells (a neuronal cell line), BF-7™ were shown to prevent the toxic effects of Aβ1-42 on these cells such as the decrease of cell viability, apoptosis, decrease of mitochondrial membrane potential and generation of reactive oxygen species. These results suggest that BF-7™ enhances both short- and long-term memory as well as attention level and prevents harmful actions of Aβ that affects function and health of the brain.

뇌과학에서 본 장기기억과 한국어 교육에의 적용 모색

이병림(Lee Byung rim) 한국어교육연구학회 2014 한국어교육연구 Vol.1 No.-

인간은 학습하는 존재이다. 학습은 기억을 근거로 이루어진다. 기억의 활동은 뇌에서 일어난다. 그러므로 본고에서는 학습과 기억의 관계를 뇌과학적 관점에서 조명하여 장기기억 전략을 연구하였다. 이를 위해 기억에 대한 전략들과 뇌의 신경세포와 시냅스라는 생물학적 관점에서 기억을 조명하였다. 뇌과학적 기억 전략으로 두 가지, 즉 '자가 재료(self-making material)'와 '심상(imagery)'기법을 도출하였고 구체적 예로 '패러프레이징(paraphrasing)'과 '애니메이션' 활용을 통합한 방법을 제시하였다. 또한, 이 방법이 장기기억에 효과적인 이유를 제시하였고 한국어 교육에의 적용점을 모색하였다. 세 개의 애니메이션과 두 개의 전래 동화를 활용한 연구 자료를 통해 더 나은 방법은 무엇인지를 조명하고, 이상적인 유의미한 애니메이션 활용 기법 한 가지를 최종적으로 제시하였다. Human beings are learning. Learning is constructed on the basis of memory. The working of memory occurs in the brain. Therefore in this study I researched the long-term memory sftrategy by enlightening the relation of learning and memory from the perspective of brain science. I researched the memory strategies and illuminated memory from the viewpoint of biology by neuron and synapse. I derived the two brain-scientific strategies such as 'self-making material' and 'imagery' technique, and I presented the integrated method of 'paraphrasing' and 'animation' application in specific example. I also presented the reason why this method is effective for the long-term memory and sought the application to Korean education. I enlightened the better method through three studies using animation and two studies using fairy tale and finally suggested one ideal and meaningful animation-using-technique.

기억처리과정의 이해

조수진 한국청각언어재활학회 2012 Audiology and Speech Research Vol.8 No.1

Memory is our ability to encode, store and retain in the human brain. Generally, there are three stages in human memory processing, which are sensory memory, short-term memory, and long-term memory. Recently, researchers tend to use the new concept of “working memory” for replacing or including the old concept of short-term memory. “Working memory” emphasizes on the manipulation of information instead of not using passive maintenance. Therefore, it is critical for cognitive information, speech perception and language learning. Based on numerous research, training of auditory working memory is able to improve some selective areas of cognitive and speech-language development. Taken together, it is needed to develop training program of auditory working memory in aural rehabilitation for hearing impaired listeners.

Long short-term memory recurrent neural network for modeling temporal patterns in long-term power forecasting for solar PV facilities: Case study of South Korea

Jung, Yoonhwa,Jung, Jaehoon,Kim, Byungil,Han, SangUk Elsevier 2020 JOURNAL OF CLEANER PRODUCTION Vol.250 No.-

<P><B>Abstract</B></P> <P>The sites selected for solar PV facilities significantly affect the amount of electric power that can be generated over the long term. Therefore, predicting the power output of a specific PV plant is important when evaluating potential PV sites. However, whether prediction models built with data from existing PV plants can be applied to other plants for long-term power forecasting remains poorly understood. In this case, topographical and meteorological conditions, which differ among sites and change over time, make it challenging to accurately estimate the potential for energy generation at a new site. This study proposes a monthly PV power forecasting model to predict the amount of PV solar power that could be generated at a new site. The forecasting model is trained with time series datasets collected over 63 months from 164 PV sites with data such as the power plant capacity and electricity trading data, weather conditions, and estimated solar irradiation. Specifically, a recurrent neural network (RNN) model with long short-term memory was built to recognize the temporal patterns in the time series data and tested to evaluate the forecasting performance for PV facilities not used in the training process. The results show that the proposed model achieves the normalized root-mean-square-error of 7.416% and the mean absolute-percentage-error (MAPE) of 10.805% for the testing data (i.e., new plants). Furthermore, when the previous 10 months’ data were used, the temporal patterns were well captured for forecasting, with a MAPE of 11.535%. Thus, the proposed RNN approach successfully captures the temporal patterns in monthly data and can estimate the potential for power generation at any new site for which weather information and terrain data are available. Consequently, this work will allow planning officials to search for and evaluate suitable locations for PV plants in a wide area.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An LSTM-RNN-based forecasting model is presented for investigation of PV sites. </LI> <LI> Time series data of spatial and meteorological conditions depict input variables. </LI> <LI> Monthly solar photovoltaic power generation at any specific site can be predicted. </LI> <LI> nRMSE of 7.416% is achieved for long-term power prediction of new candidate sites. </LI> </UL> </P>

투자 지식적 차원에서의 종합주가지수와 코스닥종합주가지수에 대한 장기기억효과 분석 : 수익률과 변동성을 중심으로

김지열 명지대학교 금융지식연구소 2004 금융지식연구 Vol.2 No.1

지금까지 대부분의 연구들은 주식가격이 합리적 기대가설(rational expectation hypothesis)과 효율적 시장가설(efficient market hypothesis)에 의해 임의보행과정(random walk process)을 따른다는 결론을 내고 있지만, 현실적으로는 이러한 임의보행과정이 실제로 주식시장의 움직임을 얼마나 정확히 설명하고 있는지에 대해서는 지금까지도 많은 의문이 제기되고 있다. 이러한 의문에 대해 본 논문에서는 우리나라의 주식시장에서 수익률(yield)과 변동성(volatility)에 관하여 장기기억효과(long-term memory effect)가 존재하는지를 종합주가지수(KOSPI : Korean Composite Stock Price Index)와 코스닥종합지수(Korea Securities Dealers Association Automated Quotations Composite Index)를 대상으로 하여 ARFIMA (fractionally integrated ARMA) 모형 검정방법을 사용하여 검정한 결과, 종합주가지수와 코스닥종합지수의 수익률과 변동성은 모두 장기기억효과를 가지고 있음을 알 수 있었다. The studies until now are concluding that stock price in stock market follows random walk process by rational expectation hypothesis and efficient market hypothesis developing a lot of linear probability models thar is many by judgment which time series data of stock market follow normal distribution by central limit theorem. However, random walk process in stock market has a lot of questions actually. Analyzed whether long-term memory effect exist in stock earning rate and volatility of Korea in thesis treating on this question. And if long-term memory effect exists, Korean composite stock price index and Korea securities dealers association automated quotations composite index analyzed what difference is. The fractionally integrated ARMA model are used to examine this thesis. In conclusions, this thesis shows existence of the long-term memory effect in Korea stock market.