• Animal cells and systems
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• 제15권4호
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• pp.279-286
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• 2011

Hypoxic ischemia injury is a common cause of functional brain damage, resulting from a decrease in cerebral blood flow and oxygen supply to the brain. The main problems associated with hypoxic ischemia to the brain are memory impairment and dopamine dysfunction. Hypothermia has been suggested to ameliorate the neurological impairment induced by various brain insults. In this study, we investigated the effects of hypothermia on memory function and dopamine synthesis following hypoxic ischemia to the brain in rats. For this purpose, a step-down avoidance task, a radial eight-arm maze task, and immunohistochemistry for tyrosine hydroxylase (TH) and 5-bromo-2'-deoxyuridine (BrdU) were performed. The present results indicated that the hypoxic ischemia-induced disturbance of the animal's performances and spatial working memory was associated with a decrement in TH expression in the substantia nigra and striatum, and an increase in cell proliferation in the hippocampal dentate gyrus. Hypothermia treatment improved the animals' performance and spatial working memory by suppressing the decrement in TH expression in the substantia nigra and striatum and the increase in cell proliferation in the dentate gyrus. We suggest that hypothermia can be an efficient therapeutic modality to facilitate recovery following hypoxic ischemia injury to the brain, presumably by modulating the dopaminergic cell loss.

• 한국광학회:학술대회논문집
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• 한국광학회 1998년도 제15회 광학 및 양자전자 학술발표회 논문집
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• pp.94-96
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• 1998

• 한국산학기술학회논문지
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• 제9권4호
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• pp.945-951
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• 2008

공간적 지역성(spatial locality) 및 시간적 지역성(temporal locality)을 동시에 향상시킬 수 있는 새로운 고성능 데이터 캐시 구조를 제안한다. 제안된 캐시 메모리는 하드웨어 프리패치 유닛과 큰 블록 크기를 갖는 직접사상(DM: direct mapped) 캐시와 작은 블록 크기를 갖는 완전 사상(FA: fully associative) 캐시의 하위 캐시 유닛으로 구성된다. 공간적 지역성은 블록 데이터를 패치하여 직접 사상 캐시에 저장함으로써 보장되며, DM 캐시 히트가 발생한 경우에 그 이웃 데이터 블록을 프리패치 함으로써 최적화 된다. 시간적 지역성은 작은 블록 데이터가 DM 캐시로부터 제거 될때 그 블록의 과거 기록에 따라서 중요한 데이터는 완전사상 캐시에 저장함으로써 보장된다. Spec2000 벤치 마크 프로그램에 대한 실험 결과에 의하면 제안된 캐시 구조는 비슷한 크기의 직접사상 캐쉬, 4웨이 연관사상(4 way set associative cache) 및 SMI(selective-mode intelligent cache) 캐쉬 [8]등의 기존의 구조에 비해서 미스 비율(miss rate)을 평균적으로 $12.53\sim23.62%$ 그리고 AMAT(average memory access time)를 평균적으로 $14.67\sim18.60%$ 줄일 수 있음을 증명하였다.

• 한국공간정보시스템학회 논문지
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• 제7권1호
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• pp.25-37
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• 2005

최근에 무선 통신의 발달과 더불어 모바일 컴퓨팅에 대한 관심이 높아지고 있다. 모바일 컴퓨팅은 사용자가 PDA, 노트북 등의 이동 가능한 모바일 장치를 휴대하고 무선 통신을 통해서 서버 컴퓨터와 자원을 함께 공유하는 환경이라 할 수 있다. 모바일 데이타베이스는 이러한 모바일 장치에 사용되는 데이타베이스를 말한다. 모바일 데이타베이스의 응용 분야로는 보험업무, 금융업무 의료 등이 있지만, 특히 사용자의 위치 정보를 활용하는 위치 기반 서비스(LBS: Location Based Service)가 중요한 응용 분야로 등장하고 있다. 이러한 모바일 환경에서 위치 기반 서비스를 제공하기 위해서는 공간 모바일 장치에서 대용량의 공간 데이타를 효율적으로 관리하기 위한 내장형 공간 MMDBMS(Main-Memory Database Management System)가 필요하다. 이에 본 논문에서는 기존의 PC용 MMDBMS인 HSQLDB를 확장하여 공간 모바일 장치에서 공간 데이타를 효율적으로 관리할 수 있는 내장형 공간 MMDBMS를 설계 및 구현하였다. 내장형 공간 MMDBMS는 ISO(International Organization for Standardization)의 공간 데이타 모델을 따르며, 공간 데이타 특성에 적합한 압축 기법인 산술 연산 코딩 기법을 제공하고, 공간 모바일 장치에 적합한 MBR 압축 및 해슁 기법을 이용한 공간 인덱스를 지원한다. 그리고, 공간 모바일 장치의 낮은 성능의 프로세서에서 공간 데이타 디스플레이 기능을 제공하고, 내장형 공간 MMDBMS와 GIS 서버 사이에서 공간 데이타 수입/수출의 성능 향상을 위한 데이타 캐슁과 동기화 기능을 지원한다.

• 아동학회지
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• 제7권1호
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• pp.85-95
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• 1986

The purpose of the present research was to study effects of experimental conditions and developmental tendency in the use of external cues in memory-for-object location in toddlers. This study consisted of two experiments. In study 1, the subjects were 12 toddlers, 18 to 23 months old ; in study 2, 30 toddlers, 24 to 41 months old. The findings showed that memory-for-object location in toddlers was different in accordance with experimental conditions; that is, memory-for-object location in the natural condition was significantly better than in the artificial condition. Effects of external cues were found ; that is, memory-for-object location was best in the condition of spatial cues, and next best in the condition of picture cues, and least good in the no cue condition.

• 수면정신생리
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• 제7권1호
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• pp.10-17
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• 2000

To investigate the neurobiological bases of learning and memory is one of the ambitious goals of modern neuroscience. The progress in this field of recent years has not only brought us closer to understanding the molecular mechanism underlying long-lasting changes in synaptic strength, but it has also provided further evidence that these mechanisms are required for memory formation. Since twenty years ago, several studies for the tests of the hypothesis that NMDA-dependent hippocampal long-term potentiation(LTP) underlies learning have been reported. Also, in the recent year, data from mutant mice showed that a potential role for NMDA-dependent LTP in hippocampal CA1 and spatial learning. Although the current evidence for the role of NMDA receptor in learning and memory is not still obvious, NMDA receptor seems to act as a critical switch for activation of a cascade of events that underlie synaptic plasticity.

• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.6-10
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• 2023

High-potential data can be predicted and stored in the cache to prevent cache misses, thus reducing the processor's request and wait times. As a result, the processor can work non-stop, hiding memory latency. By utilizing the temporal/spatial locality of memory access, the prefetcher introduced to improve the performance of these computers predicts the following memory address will be accessed. We propose a prefetcher that applies the GRU model, which is advantageous for handling time series data. Display the currently accessed address in binary and use it as training data to train the Gated Recurrent Unit model based on the difference (delta) between consecutive memory accesses. Finally, using a GRU model with learned memory access patterns, the proposed data prefetcher predicts the memory address to be accessed next. We have compared the model with the multi-layer perceptron, but our prefetcher showed better results than the Multi-Layer Perceptron.

• 생약학회지
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• 제45권1호
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• pp.48-54
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• 2014

Alzheimer's disease is progressive neurodegenerative disorder by the loss of memory and learning abilities. Codonopsis lanceolata (C. lanceolata) is traditional medicinal plant used for the treatment of inflammatory diseases. The aim of study was to evaluate the effect of steamed C. lanceolata on scopolamine-induced memory impairment in the Morris water maze test and passive avoidance test. In addition, this study investigated the neuroprotective effects of steamed C. lanceolata on glutamate-induced cell death in HT22 cells using MTT assay. The results showed that steamed C. lanceolata (500 mg/kg body weight, p.o.) reversed spatial memory impairment by scopolamine in Morris water maze test and passive avoidance test. Steamed C. lanceolata attenuated memory impairment by scopolamine compared with common C. lanceolata. In addition, administration of steamed C. lanceolata significantly also reduced cell death. We suggest that steaming process more improve cognitive enhancing and neuroprotective effect of C. lanceolata than common C. lanceolata.

• Toxicological Research
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• 제31권4호
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• pp.347-354
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• 2015

Excess manganese (Mn) is neurotoxic. Increased manganese stores in the brain are associated with a number of behavioral problems, including motor dysfunction, memory loss and psychiatric disorders. We previously showed that the transport and neurotoxicity of manganese after intranasal instillation of the metal are altered in Hfe-deficient mice, a mouse model of the iron overload disorder hereditary hemochromatosis (HH). However, it is not fully understood whether loss of Hfe function modifies Mn neurotoxicity after ingestion. To investigate the role of Hfe in oral Mn toxicity, we exposed Hfe-knockout ($Hfe^{-/-}$) and their control wild-type ($Hfe^{+/+}$) mice to $MnCl_2$ in drinking water (5 mg/mL) for 5 weeks. Motor coordination and spatial memory capacity were determined by the rotarod test and the Barnes maze test, respectively. Brain and liver metal levels were analyzed by inductively coupled plasma mass spectrometry. Compared with the water-drinking group, mice drinking Mn significantly increased Mn concentrations in the liver and brain of both genotypes. Mn exposure decreased iron levels in the liver, but not in the brain. Neither Mn nor Hfe deficiency altered tissue concentrations of copper or zinc. The rotarod test showed that Mn exposure decreased motor skills in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice (p = 0.023). In the Barns maze test, latency to find the target hole was not altered in Mn-exposed $Hfe^{+/+}$ compared with water-drinking $Hfe^{+/+}$ mice. However, Mn-exposed $Hfe^{-/-}$ mice spent more time to find the target hole than Mn-drinking $Hfe^{+/+}$ mice (p = 0.028). These data indicate that loss of Hfe function impairs spatial memory upon Mn exposure in drinking water. Our results suggest that individuals with hemochromatosis could be more vulnerable to memory deficits induced by Mn ingestion from our environment. The pathophysiological role of HFE in manganese neurotoxicity should be carefully examined in patients with HFE-associated hemochromatosis and other iron overload disorders.

• 한국컴퓨터그래픽스학회논문지
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• 제23권3호
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• pp.19-29
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• 2017

일반적으로 희소 볼륨 데이터에 대하여 고정적인 메모리 할당 방식을 사용할 경우 상당한 메모리 공간 낭비가 발생하며, 이는 대용량의 고해상도 볼륨 데이터의 경우 더 심각한 문제가 발생한다. 본 논문에서는 이러한 불필요한 메모리 낭비를 개선하기 위하여 고정적인 메모리 공간이 아닌, 유효한 정보가 저장된 복셀 만을 효과적으로 저장하는 볼륨 데이터 표현 방법을 제안하고, 이를 기존의 정적인 메모리 할당 방법, 팔진 트리 그리고 복셀 해싱 방법과 메모리 사용량 및 연산 속도 측면에서 비교 분석한다. 특히 GPU 기반의 마칭 큐브 방법의 구현에 있어 본 논문에서 제안하는 방법과 복셀 해싱 방법을 비교 분석 한다.