• Korean Journal of Materials Research
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• v.25 no.9
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• pp.429-434
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• 2015

Resistance switching memory cells were fabricated using atomically dispersed Pt-$SiO_2$ thin film prepared via RF co-sputtering. The memory cell can switch between a low-resistance-state and a high-resistance-state reversibly and reproducibly through applying alternate voltage polarities. Percolated conducting paths are the origin of the low-resistance-state, while trapping electrons in the negative U-center in the Pt-$SiO_2$ interface cause the high-resistance-state. Intermediate resistance-states are obtained through controlling the compliance current, which can be applied to multi-level operation for high memory density. It is found that the resistance value is related to the capacitance of the memory cell: a 265-fold increase in resistance induces a 2.68-fold increase in capacitance. The exponential growth model of the conducting paths can explain the quantitative relationship of resistance-capacitance. The model states that the conducting path generated in the early stage requires a larger area than that generated in the last stage, which results in a larger decrease in the capacitance.

• The Journal of the Acoustical Society of Korea
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• v.25 no.1E
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• pp.20-24
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• 2006

In this paper, we focused on the real time implementation of a speech recognition system with medium size of vocabulary considering its application to a mobile phone. First, we developed the PC based variable vocabulary word recognizer having the size of program memory and total acoustic models as small as possible. To reduce the memory size of acoustic models, linear discriminant analysis and phonetic tied mixture were applied in the feature selection process and training HMMs, respectively. In addition, state based Gaussian selection method with the real time cepstral normalization was used for reduction of computational load and robust recognition. Then, we verified the real-time operation of the implemented recognition system on the TMS320C6201 EVM board. The implemented recognition system uses memory size of about 610 kbytes including both program memory and data memory. The recognition rate was 95.86% for ETRI 445DB, and 96.4%, 97.92%, 87.04% for three kinds of name databases collected through the mobile phones.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1151-1156
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• 2002

This research was done to make the effective prescription and cope with various senile dementia. Sprague-Dawley rats were injured by ibotenic acid to make a damage on learning and memory functions of model rats. At first acquisition test and retention rest were done in the Morris water maze. And to evaluate the effects of the sample drug(GSD) on choline acetyltranferase and acetylcholine esterase, immunoreactive measurement and enzymatic activity measuring were carried out. The ibotenic acid were injected to hippocampus CA1 and CA3 area. Conclusion : GSD improved the learning ability in the acquisition test and memory function in the retention test significantly. And GSD increased the level of ChAT which is synthesizing acetylcholine in CA1 area, and at the same time it increased the level of AChE which is resolving acetylcholine. These results show that GSD improved the cholinergic catabolism and anabolism, and the increment of metabolic activity of cholinergic system. In other words, it contributes to the recovery of damaged learning and memory function by ibotenic acid. So it can be concluded that GSD will be helpful to cholinergic brain damage induced by primary or senile reduction of acetylcholine secretive activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.5
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• pp.270-276
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• 2017

The aim of this study was to investigate the effects of the water extract of Albizziae Cortex (AC) on the learning and memory impairments. AC was administered to normal mouse and scopolamine-injected amnesia mouse model. Passive avoidance test, Y-maze test, and Morris water maze test were conducted to confirm the cognitive-enhancing activities of AC. Acetylcholinesterase (AChE) activity and acetylcholine (Ach) content were measured after oral administration of AC. On the passive avoidance test, AC (200 mg/kg) significantly increased latency time and recovered scopolamine-impaired learning and memory in mice. In addition, AC (200 mg/kg) reduced Exploration time in target quadrant and reversed the scopolamine-induced cognitive impairments in the Y-maze test. Moreover, AC (200 mg/kg) increased exploration time in target quadrant and improved scopolamine-reduced escape latencies in the Morris water maze test. These effects were presented by regulatory effects of AC on AChE activity and Ach content. Taken together, AC increases cognitive-enhancing activities and ameliorates scopolamine-induced learning and memory impairment. AC might be a potential agent for prevention and treatment of amnesia and dementia.

• Journal of the Korean Society of Food Culture
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• v.36 no.6
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• pp.633-639
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• 2021

Raphanus sativus var. hortensis f. raphanistroides Makino (Korean wild radish [WR]) are root vegetables belonging to the Brassicaceae family. These radish species mostly grow in sea areas in Asia, where they have been traditionally used as a medicinal food to treat various diseases. To investigate the effect of WR on neuronal cell death in SH-SY5Y cells, beta-amyloid was used to develop the cell death model. WR attenuated neuronal cell death in SH-SY5Y and regulated the mitogen-activated protein kinase (MAPK) signaling. WR extract also inhibited acetylcholinesterase inhibitor activity. Additionally, the WR treatment group ameliorated the behavior of the memory-impaired mice in a scopolamine-induced mouse model. In the behavior test, WR treated mice showed shorter escape latency and swimming distance and improved the platform-crossing number and the swimming time within the target quadrant. Furthermore, WR prevented histological loss of neurons in hippocampal CA1 regions induced by scopolamine. This study shows that WR can prevent memory impairment which may be a crucial way for the prevention and treatment of memory dysfunction and neuronal cell death.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.176-184
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• 2021

This study aims to examine 1) the influence of festival emotional and function values on travelers' positive festival memory, festival attachment, and experience sharing behavior, and (2) the moderation effect of online friendship among the path. In the present study, the proposed model was developed based on the MTS from 340 collected participants who have experienced the festival held in Guangdong Province in China. The SPSS and AMOS were used for statistical analysis. The results revealed that emotional and function festival values are positively related to the positive festival memory of travelers; positive festival memory significantly influences festival attachment and experience sharing behavior of travelers. Meanwhile, festival attachment also has a significantly positive effect on the experience-sharing behavior of travelers. Moreover, the presented differential experience sharing behavior of travelers follows the level of their online friendship. Travelers with high online friendships presented higher sharing behavior than travelers with low online friendships. Depending on the results of this study, we could provide some theoretical implications for future festival research and online communication research. These results could provide some practical implications for festival managers to develop more communication strategies.

• Korean Journal of Metals and Materials
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• v.47 no.12
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• pp.881-886
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• 2009

Research into the replacement of injured systems and tissue in the human body is advancing rapidly. Recently, Ti-Ni shape memory alloys have shown excellent biofunctionality related to their shape memory effect and superelasticity. In this study, the effect of an acid or an alkali treatment on the bioactivity in 49Ti-Ni and 51.5Ti-48.5Ni alloys is investigated in an effort to utilize Ti-Ni alloy as a biomaterial. In addition, the biocompatibility in a SBF solution is assessed through in vitro testing. A porous surface was formed on the surface of both alloys after a chemical treatment. According to the in vitro test, apatite formed on the surfaces of both alloys. The forming rate of apatite in the Ti-rich alloy was faster that in the Ni-rich alloy. The formation of apatite provided proof of the bioactivity of the Ti-Ni alloy. A small quantity of Ni was eluted at the initial stage, whereas Ni was not found for 12 days in the Ti-rich alloy and for 8 days in the Ni-rich alloy. In the case of the treated 51.5Ti-Ni alloy, the shape memory property was worsened but the biocompatibility was improved.

• IMMUNE NETWORK
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• v.6 no.2
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• pp.93-101
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• 2006

Background: Memory T lymphocytes of the immune system provide long-term protection in response to bacterial or viral infections/immunization. Ag concentration has also been postulated to be important in determining whether T cell differentiation favors effector versus memory cell development. In the present study we hypothesized that naive Ag-specific $CD4^+$ T cells briefly stimulated with different Ag doses at the primary exposure could affect establishment of memory cell pool after secondary immunization. Methods: To assess this hypothesis, the response kinetics of DO11.10 TCR $CD4^+$ T cells primed with different Ag doses in vitro was measured after adoptive transfer to naive BALB/c mice. Results: Maximum expansion was shown in cells primarily stimulated with high doses of ovalbumin peptide $(OVA_{323-339})$, whereas cells in vitro stimulated with low dose were expanded slightly after in vivo secondary exposure. However, the cells primed with low $OVA_{323-339}$ peptide dose showed least contraction and established higher number of memory cells than other treated groups. When the cell division was analyzed after adoptive transfer, the high dose Ag-stimulated donor cells have undergone seven rounds of cell division at 3 days post-adoptive transfer. However, there was very few division in naive and low dose of peptide-treated group. Conclusion: These results suggest that primary stimulation with a low dose of Ag leads to better memory $CD4^+$ T cell generation after secondary immunization. Therefore, these facts imply that optimally primed $CD4^+$ T cells is necessary to support effective memory pool following administration of booster dose in prime-boost vaccination.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1183-1184
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• 2008

• ETRI Journal
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• v.35 no.3
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• pp.439-447
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• 2013

To increase device memory yield, many manufacturers use incorporated redundancy to replace faulty cells. In this redundancy technology, the implementation of an effective redundancy analysis (RA) algorithm is essential. Various RA algorithms have been developed to repair faults in memory. However, nearly all of these RA algorithms have low analysis speeds. The more densely compacted the memory is, the more testing and repair time is needed. Even if the analysis speed is very high, the RA algorithm would be useless if it did not have a normalized repair rate of 100%. In addition, when the number of added spares is increased in the memory, then the memory space that must be searched with the RA algorithms can exceed the memory space within the automatic test equipment. A very efficient RA algorithm using simple calculations is proposed in this work so as to minimize both the repair time and memory consumption. In addition, the proposed algorithm generates an optimal solution using a tree-based algorithm in each fault group. Our experiment results show that the proposed RA algorithm is very efficient in terms of speed and repair.