How the Efficiency of Mutual Funds in India Have Evolved over Time: A Study on Selected Mutual Funds in India

2020 ◽  
Vol 14 (1) ◽  
pp. 3-26
Author(s):  
Radhika Prosad Datta ◽  
Jayanta Kumar Seal ◽  
Jayanta Kumar Seal
Keyword(s):  
Market Efficiency ◽  
Mutual Funds ◽  
Hurst Exponent ◽  
Long Term Memory ◽  
Term Memory ◽  
Significant Difference ◽  
Over Time

This paper studies the long term memory of the returns from selected mutual funds from the large, mid & small cap and hybrid categories in India, over 10 years starting from 2008-09. The Hurst exponent is used to study the persistence and anti-persistent or mean-reverting trends and hence the market efficiency of the returns of the funds across various categories and periods are analyzed. The findings indicate, that there seems to be no significant difference in the market efficiency of various mutual funds across the categories studied over our period of interest. Although for certain periods all the categories do show persistent or anti-persistent behavior, there does not seem to be any particular pattern in such behaviour.

scholarly journals COMPLEXITY-BASED ANALYSIS OF THE ALTERATIONS IN THE STRUCTURE OF CORONAVIRUSES

Fractals ◽  
2021 ◽  
Vol 29 (02) ◽  
pp. 2150123
Author(s):  
HAMIDREZA NAMAZI ◽  
ALI SELAMAT ◽  
ONDREJ KREJCAR
Keyword(s):  
Hurst Exponent ◽  
Complex Structure ◽  
Approximate Entropy ◽  
Sample Entropy ◽  
Long Term Memory ◽  
Complex Structures ◽  
Term Memory ◽  
The World ◽  
First Time

The coronavirus has influenced the lives of many people since its identification in 1960. In general, there are seven types of coronavirus. Although some types of this virus, including 229E, NL63, OC43, and HKU1, cause mild to moderate illness, SARS-CoV, MERS-CoV, and SARS-CoV-2 have shown to have severer effects on the human body. Specifically, the recent known type of coronavirus, SARS-CoV-2, has affected the lives of many people around the world since late 2019 with the disease named COVID-19. In this paper, for the first time, we investigated the variations among the complex structures of coronaviruses. We employed the fractal dimension, approximate entropy, and sample entropy as the measures of complexity. Based on the obtained results, SARS-CoV-2 has a significantly different complex structure than SARS-CoV and MERS-CoV. To study the high mutation rate of SARS-CoV-2, we also analyzed the long-term memory of genome walks for different coronaviruses using the Hurst exponent. The results demonstrated that the SARS-CoV-2 shows the lowest memory in its genome walk, explaining the errors in copying the sequences along the genome that results in the virus mutation.

scholarly journals Individual Differences in Learning Efficiency

2019 ◽  
Vol 28 (6) ◽  
pp. 607-613
Author(s):  
Kathleen B. McDermott ◽  
Christopher L. Zerr
Keyword(s):  
Individual Differences ◽  
Experimental Approach ◽  
Long Term Memory ◽  
Positive Relation ◽  
Future Directions ◽  
Term Memory ◽  
Learning Efficiency ◽  
Rate Of Learning ◽  
Over Time

Most research on long-term memory uses an experimental approach whereby participants are assigned to different conditions, and condition means are the measures of interest. This approach has demonstrated repeatedly that conditions that slow the rate of learning tend to improve later retention. A neglected question is whether aggregate findings at the level of the group (i.e., slower learning tends to improve retention) translate to the level of individual people. We identify a discrepancy whereby—across people—slower learning tends to coincide with poorer memory. The positive relation between learning rate (speed of learning) and retention (amount remembered after a delay) across people is referred to as learning efficiency. A more efficient learner can acquire information faster and remember more of it over time. We discuss potential characteristics of efficient learners and consider future directions for research.

Movement Retrieval from Long-Term Memory: Physical versus Mental Rehearsal

1987 ◽  
Vol 65 (2) ◽  
pp. 603-612 ◽  
Author(s):  
Susan L. Puretz
Keyword(s):  
Original Learning ◽  
Long Term Memory ◽  
Mental Rehearsal ◽  
Dance Movement ◽  
Term Memory ◽  
Covert Rehearsal ◽  
Significant Difference ◽  
Rehearsal Strategies ◽  
Dance Movements

Despite references in the psychomotor literature regarding the use of rehearsal strategies in recovering movements from longer term memory, no significant difference between physical (overt) and mental (covert) rehearsal strategies for retrieving a complex dance movement over 30 min., 2 days, and 1 wk. were observed for 72 college women in beginning dance classes. Further, no rehearsal was as effective as either physical or mental rehearsal for retrieving dance movements for up to 1 wk. after original learning by these inexperienced dancers. The findings raise the possibility that other forms of retrieval than those already proposed are used to recover complex dance movements from longer term memory.

scholarly journals Features of subsyndromal and persistent delirium

2012 ◽  
Vol 200 (1) ◽  
pp. 37-44 ◽  
Author(s):  
David Meagher ◽  
Dimitrios Adamis ◽  
Paula Trzepacz ◽  
Maeve Leonard
Keyword(s):  
Rating Scale ◽  
Cognitive Test ◽  
Long Term Memory ◽  
Thought Process ◽  
Diagnostic Features ◽  
Term Memory ◽  
Subsyndromal Delirium ◽  
Short And Long Term ◽  
Over Time

BackgroundLongitudinal studies of delirium phenomenology are lacking.AimsWe studied features that characterise subsyndromal delirium and persistent delirium over time.MethodTwice-weekly evaluations of 100 adults with DSM-IV delirium using the Delirium Rating Scale – Revised-98 (DRS-R98) and Cognitive Test for Delirium (CTD). The generalised estimating equation method identified symptom patterns distinguishing full syndromal from subsyndromal delirium and resolving from persistent delirium.ResultsParticipants (mean age 70.2 years (s.d. = 10.5)) underwent 323 assessments (range 2–9). Full syndromal delirium was significantly more severe than subsyndromal delirium for DRS-R98 thought process abnormalities, delusions, hallucinations, agitation, retardation, orientation, attention, and short- and long-term memory items, and CTD attention, vigilance, orientation and memory. Persistent full syndromal delirium had greater disturbance of DRS-R98 thought process abnormalities, delusions, agitation, orientation, attention, and short- and long-term memory items, and CTD attention, vigilance and orientation.ConclusionsFull syndromal delirium differs from subsyndromal delirium over time by greater severity of many cognitive and non-cognitive symptoms. Persistent delirium involves increasing prominence of recognised core diagnostic features and cognitive impairment.

Analysis of Long-Term Memory in the Mexican Exchange Market Using a Fuzzy Hurst Exponent: Does Intervention Matter?

2018 ◽  
Vol 26 (Suppl. 1) ◽  
pp. 71-92
Author(s):  
Klender Cortez ◽  
Martha Del Pilar Rodríguez
Keyword(s):  
Exchange Rate ◽  
Central Bank ◽  
Exchange Rates ◽  
Hurst Exponent ◽  
The Other ◽  
Long Term Memory ◽  
Exchange Market ◽  
Term Memory ◽  
Monetary Authorities

The following article aims to detect if long-term memory exists in the Mexican exchange rate market. This research was conducted between 1992 and 2016, during which time different intervention mechanisms were presented. The interventions were divided as follows: a) crawling bands (01/1992–12/1994), b) free flotation in crisis (01/1995–07/1996), c) mixed operations with purchases and sales of dollars by the Central Bank (08/1996–06/2001), d) free flotation (07/2001–04/2003), e) accumulation of international reserves (05/2003–02/2009, f) mixed auctions (03/2009–02/2016), and g) free flotation with interest rate increases (03/2016–12/2016). To detect the presence of long-term memory in the peso–dollar exchange rates, we proposed a fuzzy Hurst exponent. The results evidenced distinct types of behaviors depending on the grade of intervention. Compared to a free-floating regime, persistence and fuzzy Hurst values decreased when the Central Bank intervened in the exchange market. On the other hand, uncertainty increased when monetary authorities imposed a mechanism for buying and selling dollars without an exchange rate target.

scholarly journals The Influence of LED Lighting on Attention and Long-Term Memory

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Chung Won Lee ◽  
Jin Ho Kim
Keyword(s):  
Retention Volume ◽  
Word Fragment ◽  
Long Term Memory ◽  
Memory Retention ◽  
Experimental Conditions ◽  
Term Memory ◽  
Led Lighting ◽  
Significant Difference ◽  
Led Lights

The fact that the illuminance of LED lights affects human attention and long-term memory has been verified through various studies, but there are no consistent research results about what level of illuminance is effective. The aims of this study were to systematically verify the effects of LED lighting on attention and long-term memory. The experiment was designed with four illuminance levels—300 lx, 400 lx, 500 lx, and 1,000 lx—as experimental conditions to determine the effects of LED lights on attention and long-term memory. Participants in the experiment were 18 college students. The attention task was performed using a handmade attention measuring instrument. Long-term memory was measured by the word fragment completion (hereinafter, referred to as “WFC”) task on the memory retention volume of the learning task that was learned exactly 24 hours before. Of the total 20 tasks, the ratio of correctly retrieval tasks was used as a dependent variable. As a result, attention showed the highest performance with a mean performance of 19.39 (SD = 3.78) at 1,000 lx. A statistically significant difference was also found between the 1,000 lx and 300  lx conditions (p=0.01). On the contrary, long-term memory showed the highest retrieval rate at an average of 58.06% (SD = 22.57) at 400 lx, and long-term memory performance was better in the order of 500 lx (mean = 48.89, SD = 20.33), 1,000 lx (mean = 45.83, SD = 23.53), and 300 lx (Mean = 43.33, SD = 19.10). Statistically, there was a significant difference between 300 lx and 400 lx (p=0.01), 400 lx and 1,000 lx (p=0.01). Through this study, it was verified that the effects of attention and long-term memory are different according to the illuminance of LED lighting, and these results can be important data to clarify the influence of light on human memory in the future.

scholarly journals ERROR ASSESSMENT IN MODELING WITH FRACTAL BROWNIAN MOTIONS

Fractals ◽  
2013 ◽  
Vol 21 (03n04) ◽  
pp. 1350018 ◽  
Author(s):  
BINGQIANG QIAO ◽  
SIMING LIU
Keyword(s):  
Time Series ◽  
Fractal Dimension ◽  
Hurst Exponent ◽  
Long Term Memory ◽  
Error Assessment ◽  
Data Sampling ◽  
Brownian Motions ◽  
Term Memory ◽  
Rescaled Range

To model a given time series F(t) with fractal Brownian motions (fBms), it is necessary to have appropriate error assessment for related quantities. Usually the fractal dimension D is derived from the Hurst exponent H via the relation D = 2-H, and the Hurst exponent can be evaluated by analyzing the dependence of the rescaled range 〈|F(t + τ) - F(t)|〉 on the time span τ. For fBms, the error of the rescaled range not only depends on data sampling but also varies with H due to the presence of long term memory. This error for a given time series then can not be assessed without knowing the fractal dimension. We carry out extensive numerical simulations to explore the error of rescaled range of fBms and find that for 0 < H < 0.5, |F(t + τ) - F(t)| can be treated as independent for time spans without overlap; for 0.5 < H < 1, the long term memory makes |F(t + τ) - F(t)| correlated and an approximate method is given to evaluate the error of 〈|F(t + τ) - F(t)|〉. The error and fractal dimension can then be determined self-consistently in the modeling of a time series with fBms.

scholarly journals Tracing the path of forgetting in rule abstraction and exemplar retrieval

2018 ◽  
Vol 71 (11) ◽  
pp. 2261-2281 ◽  
Author(s):  
Janina A Hoffmann ◽  
Bettina von Helversen ◽  
Regina A Weilbächer ◽  
Jörg Rieskamp
Keyword(s):  
Retention Interval ◽  
Decision Makers ◽  
Long Term Memory ◽  
Rule Based ◽  
Term Memory ◽  
Initial Learning ◽  
Rule Abstraction ◽  
The Individual ◽  
Over Time

People often forget acquired knowledge over time such as names of former classmates. Which knowledge people can access, however, may modify the judgement process and affect judgement accuracy. Specifically, we hypothesised that judgements based on retrieving past exemplars from long-term memory may be more vulnerable to forgetting than remembering rules that relate the cues to the criterion. Experiment 1 systematically tracked the individual course of forgetting from initial learning to later tests (immediate, 1 day, and 1 week) in a linear judgement task facilitating rule-based strategies and a multiplicative judgement task facilitating exemplar-based strategies. Practising the acquired judgement strategy in repeated tests helped participants to consistently apply the learnt judgement strategy and retain a high judgement accuracy even after a week. Yet, whereas a long retention interval did not affect judgements in the linear task, a long retention interval impaired judgements in the multiplicative task. If practice was restricted as in Experiment 2, judgement accuracy suffered in both tasks. In addition, after a week without practice, participants tried to reconstruct their judgements by applying rules in the multiplicative task. These results emphasise that the extent to which decision makers can still retrieve previously learned knowledge limits their ability to make accurate judgements and that the preferred strategies change over time if the opportunity for practice is limited.

scholarly journals Tracking the relation between gist and item memory over the course of long-term memory consolidation

2021 ◽  
Author(s):  
Tima Zeng ◽  
Alexa Tompary ◽  
Anna C. Schapiro ◽  
Sharon L. Thompson-Schill
Keyword(s):  
Memory Consolidation ◽  
Item Memory ◽  
Long Term Memory ◽  
Local Center ◽  
Term Memory ◽  
The World ◽  
Human Participants ◽  
Spatial Locations ◽  
Over Time

AbstractOur experiences in the world support memories not only of specific episodes but also of the generalities (the ‘gist’) across related experiences. It remains unclear how these two types of memories evolve and influence one another over time. 173 human participants encoded spatial locations from a distribution and reported both item memory (specific locations) and gist memory (center for the locations) across one to two months. After one month, gist memory was preserved relative to item memory, despite a persistent positive correlation between them. Critically, item memories were biased towards the gist over time; however, with a spatial outlier item, the local center excluding the outlier became the source of bias, instead of the reported center overweighting the outlier. Our results suggest that the extraction of gist is sensitive to the regularities of items, and that the gist starts to guide item memories over longer durations as their relative strengths change.

scholarly journals The Effect of Visual Long-Term Memory on Eye Movements over Time

2019 ◽  
Vol 19 (10) ◽  
pp. 149a
Author(s):  
Lisa F Schwetlick ◽  
Hans A Trukenbrod ◽  
Ralf Engbert
Keyword(s):  
Eye Movements ◽  
Long Term Memory ◽  
Term Memory ◽  
Over Time
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