• Journal of information and communication convergence engineering
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• v.22 no.2
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• pp.98-108
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• 2024

Scrypt is a password-based key derivation function proposed by Colin Percival in 2009 that has a memory-hard structure. Scrypt has been intentionally designed with a memory-intensive structure to make password cracking using ASICs, GPUs, and similar hardware more difficult. However, in this study, we thoroughly analyzed the operation of Scrypt and proposed strategies to maximize computational parallelism in GPU environments. Through these optimizations, we achieved an outstanding performance improvement of 8284.4% compared with traditional CPU-based Scrypt computations. Moreover, the GPU-optimized implementation presented in this paper outperforms the simple GPU-based Scrypt processing by a significant margin, providing a performance improvement of 204.84% in the RTX3090. These results demonstrate the effectiveness of our proposed approach in harnessing the computational power of GPUs and achieving remarkable performance gains in Scrypt calculations. Our proposed implementation is the first GPU implementation of Scrypt, demonstrating the ability to efficiently crack Scrypt.

• Journal of Korean Neurosurgical Society
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• v.44 no.5
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• pp.295-302
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• 2008

Objective: Premorbid demographic backgrounds of injured individuals are likely to reflect more accurately the status of patients with traumatic brian injury (TBI) than clinical factors. However, the concrete study about the relationship between the demographic factors and neurocognitive function in TBI patients has not been reported. The object of this study was to evaluate the effect of premorbid demographic factors on the recovery of neurocognitive function following TBI. Methods: From July 1998 to February 2007, 293 patients (male: 228, female: 65) with a history of head injury, who had recovered from the acute phase, were selected from our hospital to include in this study. We analyzed the effect of premorbid demographic factors including age, sex, educational level and occupation on the recovery of neurocognitive function in each TBI subgroup as defined by Glasgow Coma Scale (GCS) score. Intelligence and memory are components of neurocognitive function, and the Korean Wechsler Intelligence Scale (K-WAIS) and the Korean memory assessment scale (K-MAS) were used in this study. The results were considered significant at p<0.05. Results: The higher level of education was a good prognostic factor for intelligence regardless of GCS score and younger age group showed a better result for memory with an exception of severe TBI group. In the severe TBI group, the meaningful effect of demographic factors was not noted by the cause of influence of severe brain injury. Conclusion: The demographic factors used in this study may be helpful for predicting the precise prognosis and developing an appropriate rehabilitation program for TBI patients.

• Korean Journal of Biological Psychiatry
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• v.21 no.4
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• pp.175-181
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• 2014

Objectives It was the aim to examine the association of the thyroid-related hormones with cognitive function, depression, and subjective memory impairment in community-dwelling elders with questionable dementia. Methods The sample consisted of 399 community residents with 'questionable dementia' aged 60 or over in whom serum thyroid-related hormones [thyroid stimulating hormone (TSH) and thyroxine] had been assayed. Cognitive impairment was defined using the Korean version of the Consortium Establish a Registry for Alzheimer's Disease. Depression was diagnosed using the Korean version of Geriatric Depression Scale and subjective memory complaint (SMC) was checked using the subjective memory complaints questionnaire (SMCQ). Age, gender, education, and the presence of apolipoprotein E {\varepsilon}4 were included as covariates. Results There was a significant positive association between verbal fluency test (VFT) score and serum TSH levels (p = 0.01). There was a significant negative association between SMCQ total score and word list memory test (WLMT)(p = 0.002) or word list recall test (WLRT) score (p = 0.013). Conclusions Lower serum TSH levels were associated with semantic memory (VFT), and we found that SMC was associated with episodic memory (WLMT and WLRT) in this sample.

• Journal of the Korea Society of Computer and Information
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• v.22 no.5
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• pp.1-9
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• 2017

Recently, flash memory has been in a great demand from embedded system sectors for storage devices. However, program/erase (P/E) cycles per block are limited on flash memory. For the limited number of P/E cycles, many wear leveling techniques are studied. They prolonged the life time of flash memory using information tables. As one of the techniques, block erase table (BET) method using a bit array table was studied for embedded devices. However, it has a disadvantage in that performance of wear leveling is sharply low, when the consumption of memory is reduced. To solve this problem, we propose a novel wear leveling technique using Sampling-based Block Erase Table (SBET). SBET relates one bit of the bit array table to each block by using exclusive OR operation with round robin function. Accordingly, SBET enhances accuracy of cold block information and can prevent to decrease the performance of wear leveling. In our experiment, SBET prolongs life time of flash memory by up to 88%, compared with previous techniques which use a bit array table.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.1922-1940
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• 2019

IP address lookup is a function to determine nexthop for a given destination IP address. It takes an important role in modern routers because of its computation time and increasing Internet traffic. TCAM-based IP lookup approaches can exploit the capability of parallel searching but have a limitation of its size due to latency, power consumption, updatability, and cost. On the other hand, multibit trie-based approaches use SRAM which has relatively low power consumption and cost. They reduce the number of memory accesses required for each lookup, but it still needs several accesses. Moreover, the memory efficiency and updatability are proportional to the number of memory accesses. In this paper, we propose a novel architecture using an Indexed Multibit Trie (IMT) which is based on combined TCAM and SRAM. In the proposed architecture, each lookup takes at most two memory accesses. We present how the IMT is constructed so as to be memory-efficient and fast updatable. Experiment results with real-world forwarding tables show that our scheme achieves good memory efficiency as well as fast updatability.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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• pp.415-425
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• 2022

Memory formation in the hippocampus is formed and maintained by circadian clock genes during sleep. Sleep deprivation (SD) can lead to memory impairment and neuroinflammation, and there remains no effective pharmacological treatment for these effects. Myricetin (MYR) is a common natural flavonoid that has various pharmacological activities. In this study, we investigated the effects of MYR on memory impairment, neuroinflammation, and neurotrophic factors in sleep-deprived rats. We analyzed SD-induced cognitive and spatial memory, as well as pro-inflammatory cytokine levels during SD. SD model rats were intraperitoneally injected with 10 and 20 mg/kg/day MYR for 14 days. MYR administration significantly ameliorated SD-induced cognitive and spatial memory deficits; it also attenuated the SD-induced inflammatory response associated with nuclear factor kappa B activation in the hippocampus. In addition, MYR enhanced the mRNA expression of brain-derived neurotropic factor (BDNF) in the hippocampus. Our results showed that MYR improved memory impairment by means of anti-inflammatory activity and appropriate regulation of BDNF expression. Our findings suggest that MYR is a potential functional ingredient that protects cognitive function from SD.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.101-101
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• 2020

Traditional stochastic simulation of hydroclimatological variables often underestimates the variability and correlation structure of larger timescale due to the difficulty in preserving long-term memory. However, the Long Short-Term Memory (LSTM) model illustrates a remarkable long-term memory from the recursive hidden and cell states. The current study, therefore, employed the LSTM model in stochastic generation of hydrologic and climate variables to examine how much the LSTM model can preserve the long-term memory and overcome the drawbacks of conventional time series models such as autoregressive (AR). A trigonometric function and the Rössler system as well as real case studies for hydrological and climatological variables were tested. Results presented that the LSTM model reproduced the variability and correlation structure of the larger timescale as well as the key statistics of the original time domain better than the AR and other traditional models. The hidden and cell states of the LSTM containing the long-memory and oscillation structure following the observations allows better performance compared to the other tested conventional models. This good representation of the long-term variability can be important in water manager since future water resources planning and management is highly related with this long-term variability.

• Korean Journal of Biological Psychiatry
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• v.22 no.2
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• pp.63-77
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• 2015

Objectives The combination extract of four kinds of herbs, Gastrodia elata, Liriope platyphylla, Dimocarpus longan, and Salvia miltiorrhiza, has shown to have memory improving effects in mice. The aim of this study was to investigate the efficacy and safety of the herbal mixture for improving working memory as well as microstructural changes in white matter integrity in individuals with subjective memory complaints. Methods Seventy-five individuals with subjective memory complaints were assigned to receive either placebo (n = 15) or herbal mixture (low-dose group, n = 30 and high-dose group, n = 30) supplementation in an 8-week, randomized, double-blind, placebo-controlled clinical trial. Changes in working memory performance and fractional anisotropy (FA) values reflecting white matter integrity from baseline to 8-week endpoint were assessed. Results The herbal mixture group showed an increase in working memory performance compared to the placebo group (p for interaction = 0.001). In addition, the herbal mixture group showed an increase in FA values in the temporo-parietal regions (corrected p < 0.05), which are crucially involved in working memory function and are among the most affected regions in patients with cognitive impairments. Conclusions Findings from this study indicate that the herbal mixture may be a promising therapeutic option for individuals with subjective memory complaints.

• Korean Journal of Biological Psychiatry
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• v.12 no.2
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• pp.207-215
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• 2005

Objectives:This study was to compare verbal memory ability among patients with schizophrenia, bipolar manic patients and unipolar depressive patients, and to understand their charicteristics of memory process. Methods:All subjects were hospitalized patients and had been interviewed by using the Structured Clinical Interview for DSM-IV(SCID). Schizophrenic patients(N=40), bipolar manic patients(N=17), and unipolar depressive patients(N=20) were assessed with K-AVLT for verbal memory and with K-WAIS for verbal IQ. Three groups were compared regarding total immediate recall, delayed recall, delayed recognition, learning curve, memory retention, and retrieval efficiency under controlled verbal IQ. Multiple regression analysis was performed to find which clinical factors have an influence on verbal memory ability. Results:In MANCOVA, differences of verbal memory test scores among the groups were statistically significant(F=1.800, p<.05). In post hoc analysis, Patients with schizophrenia and bipolar mania showed poorer performance in immediate recall, delayed recall, delayed recognition, retrieval efficiency than unipolar depres- sive patients. And schizophrenics performed poorly in delayed recall, delayed recognition, retrieval efficiency than nonpsychotic affective disorder group, but no difference in total immediate recall, delayed recall, delayed recognition, retrieval efficiency between the schizophrenic group and the psychotic affective group. Conclusions:These results partially confirm previous reports of verbal memory ability among major psychiatric disorders. Our results showed that psychotic symptoms were related with verbal memory, and longer duration of illness was related with poorer performance in schizophrenia and unipolar depression.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.127-135
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• 2009

Most traffic information that drivers receive while driving are stored in their short-term memory and disappear within a few seconds. Contemporary modeling approaches using a dummy variable can't fully explain this phenomenon. As such, this study proposes to use utility functions of real-time in-vehicle traffic safety information (IVTSI), analyzing its safety impacts based on empirical data from an on-site driving experiment at signalized intersection approach with a limited visibility. For this, a driving stability evaluation model is developed based on driver's driving speed choice, applying an ordered probit model. To estimate the specified utility functions, the model simultaneously accounts for various factors, such as traffic operation, geometry, road environment, and driver's characteristics. The results show three significant facts. First, a normal density function (exponential function) is appropriate to explain the utility of IVTSI proposed under study over time. Second, the IVTSI remains in driver's short-term memory for up to nearly 22 second after provision, decreasing over time. Three, IVTSI provision appears more important than the geometry factor but less than the traffic operation factor.