• 정보처리학회논문지B
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• 제10B권5호
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• pp.575-578
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• 2003

SPIHT는 수행속도가 빠르고 효율적인 웨이블릿 기반의 이미지 압축 알고리즘으로 잘 알려져 있다. 그러나, SPIHT는 알고리즘 수행에 필요한 제로트리 및 계수의 상태를 저장하기 위하여 리스트 구조를 사용하고 있어 추가 메모리론 요구하며, 비트율의 증가에 따라 메모리 요구량이 증가하는 단점을 가진다. 본 논문에서는 SPIHT 알고리즘을 수행하는데 있어 추가 메모리를 요구하지 않는 MZP-DFS 알고리즘을 제안한다. 제안된 기법은 깊이우선 순서에 따라 공간트리를 탐색하고 테스트 함수 및 복원 계수의 LSB를 이용함으로써 추가 메모리를 제거하였으며 SPIHT와 동일한 성능을 가진다. MZP-DFS는 추가 메모리를 요구하지 않기 때문에 하드웨어 제작비용을 절감할 수 있으며, 각각의 공간트리를 병렬적으로 수행할 수 있기 때문에 실시간 이미지 압축에 적합하다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.191-194
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• 2001

최근 메모리 가격의 하락과 함께 주기억 장치 기반 데이터베이스 기술의 필요성이 대두되고 있다. 또한 불특정 다수가 인터넷 환경을 통해 이용하는 Web GIS(Geographical Information System)는 데이터의 변경보다는 분석을 위한 데이터 검색이 많으며 고속의 처리를 요구한다. 그러므로 Web GIS를 위한 데이터 저장 하부구조로서 디스크를 기반으로 하는 것보다 메모리를 기반으로 함이 바람직하다. 이 논문에서는 Web GIS에서 널리 사용되고 있는 다차원 공간 데이터를 주기억 장치에 보다 적은 저장 용량으로 표현할 수 있는 방법으로서 상대 좌표값과 MBR(Minimum Sounding Rectangle)의 크기를 이용한 데이터 표현법을 제안한다. 그리고 점 질의나 영역 질의를 간단한 방법으로 처리하는 메모리 기반 공간 색인 기법을 제안한다. 실험 결과 색인의 크기와 MBR 비교 연산의 횟수 측면에서 불균일 분포 데이터에서도 좋은 성능을 보임을 알 수 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.315-319
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• 2009

Astragalus Membranaceus (AM) is a useful Korean herb that has been clinically prescribed for stress-related illness. The objective of the present study was to examine the anti-stress effects of AM on repeated stress-induced alterations of anxiety, learning and memory in rats. Restraint stress was administered for 14 days (2h/day) and AM (400mg/kg) given by oral administration, in the AM group, for the same period. Starting on the eighth day, the rats were tested for spatial memory on the Morris water maze test (MW) and for anxiety on the elevated plus maze (EPM). Changes of expression on immunohistochemistry were studied for cholineacetyl transferase (ChAT) and tyrosine hydroxylase (TH) in the brain. The results showed that the rats treated with AM had significantly reduced stress-induced deficits on learning and memory on the spatial memory tasks. In addition, the ChAT immunoreactivities were increased. In the EPM, treatment with AM increased the time spent in the open arms (p<0.001) compared to the control group. In addition, AM treatment also normalized increases of TH expression in the LC (p<0.001). In conclusion, administration of AM improved spatial learning and memory and reduced stress-induced anxiety. Thus, the present results suggest that AM is able to recover behavioral and neurochemical impairments induced by stress.

• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.371-376
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• 2010

Glycyrrhizae radix (GR) is an herbal medicine that is commonly used in the East Asia for treating a variety of diseases, including stomach disorders. The objective of the present study was to examine the anti-stress effects of GR on repeated stress-induced alterations of anxiety, learning and memory in rats. Restraint stress was administered for 14 days (2 h/day) to the rats in the Control and GR groups (400 mg/kg/day, PO). Starting on the eighth day, the rats were tested for spatial memory on the Morris water maze test (MW) and for anxiety on the elevated plus maze (EPM). We studied the changes of the expressions of cholineacetyl transferase (ChAT) and tyrosine hydroxylase (TH) in the locus coerleus (LC) using immunohistochemistry. The results showed that the rats treated with GR had significantly reduced stress-induced deficits on their learning and memory on the spatial memory tasks. In addition, the ChAT immunoreactivities were increased. Gor the EPM, treatment with GR increased the time spent in the open arms (p<0.001) as compared to that of the control group. Moreover, GR treatment also normalized the increases of the TH expression in the LC (p<0.001). In conclusion, administration of GR improved spatial learning and memory and reduced stress-induced anxiety. Thus, the present results suggest that GR has the potential to attenuate the behavioral and neurochemical impairments caused by stress.

• Biomolecules & Therapeutics
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• 제16권3호
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• pp.173-178
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• 2008

Several lines of evidence indicate that scopolamine as a nonselective muscarinic antagonist disrupts object recognition performance and spatial working memory when administered systemically. In the present study, we investigated the different effects of scopolamine on acquisition, consolidation, and retrieval phases of object recognition performance and spatial working memory using the object recognition and the Morris water maze tasks in mice. In the acquisition phase test, scopolamine decreased recognition index on object recognition task and the trial 1 to trial 2 differences on Morris water maze task. In the consolidation and retrieval phase tests, scopolamine also decreased recognition index on object recognition task, where as scopolamine did not exhibited any effects on the Morris water maze task.

• 한국공간구조학회논문집
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• 제18권2호
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• pp.109-119
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• 2018

In this paper a systematic numerical analysis is performed to obtain the energy dissipation and re-centering capacities of diagonal steel braced frames subjected to cyclic loading. This diagonal steel bracing systems are fabricated with super-elastic SMA (Shape Memory Alloy) braces in order to develop a recentering seismic resistance system without residual deformation. The three-dimensional nonlinear finite element models are constructed to investigate the horizontal stiffness, drifts and failure modes of the re-centering bracing systems.

• 대한간호학회지
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• 제49권3호
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• pp.317-328
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• 2019

Purpose: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. Methods: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered $80{\mu}g/kg$ ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. Results: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. Conclusion: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.

• Asian-Australasian Journal of Animal Sciences
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• 제15권6호
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• pp.900-904
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• 2002

The duration of spatial memory in cattle is potentially important for grazing management. The ability of livestock to remember the location of food patches may lead to uneven range use. In this experiment, how long cattle are able to remember food locations was determined. Six steers were used to conduct this study in a pasture with an 8 row by 8 column grid of 64 plastic containers 5 meters apart. Four randomly chosen containers were loaded with feed pellets. All steers were trained to find the loaded locations until a minimum of empty containers were visited. After this initial training, each steer was tested at 5, 10, 20 and 48 days post-training. Total number of visits (TV), number of containers visited (NC), the ratio of loaded containers (LC) to NC were recorded. Once the steers learned the locations of loaded containers NC did not increase with time since last training up to 48 days (p>0.05). Logarithmic transformation of NC (LNC) was 0.70 and 0.80 for the control and 48 day treatments, respectively. Steers were equally efficient in locating containers with feed. The steers also showed that their ability in locating food was much better than expected by chance (Z>1.62). Findings of the present study do not suggest using spatial memory decay as a tool to promote better grazing distribution. Because steers remembered food locations accurately for at least 48 days.

• 대한임베디드공학회논문지
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• 제9권5호
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• pp.253-260
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• 2014

European Space Agency has recognized Integrated Modular Avionics and ARINC specification 653 as avionics computer system for space application. Integrated Modular Avionics specification reduces the space by integrating a system composed of many electronic devices into a computer. recent researches have been studying how to apply the ARINC 653 into an open source operating system, such as Linux. These studies have concentrated on partition scheduling for time separation. However, requirements to guarantee spatial separation should be further analyzed to ensure deterministic execution time. Therefore, memory management is needed to verify spatial isolation on Linux systems. This research proposes a new method to accomplish spatial isolation for the ARINC 653 specification in Linux. We have added new data structures and system calls to handle functionalities for spatial separation. They are used during the partition startup process. The proposed method was evaluated on the LEON4 processor, which is the next generation microprocessor to be used in the future space missions. All implementations confirm that spatial isolation of the ARINC 653 specification was accomplished.

• 한국실내디자인학회논문집
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• 제24권2호
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• pp.117-124
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• 2015

With the modern society approaching, a lot of new paradigms have been created which can be explained by the existing space notions while suspicions on the true essence and existence of space have been raised. Ontology regards as the beginning the cause for a 'Field' which will be faced for the research of the essence of a space where 'being-in-the-world' exists. This study has analyzed the existing method of space construction in the spatial thinking and works of Peter Zumthor who mentioning ontological viewpoint as the physiological background of his works so that the ontological spatial concept may be clarified. The following is the study results. First, in order to construct the structures of his own designing into a 'Field' for experiencing the existential meaning, Zumthor chose a reductive pattern with the entire additional elements removed. The materials leading the subjects to call attention to memory and experience and the methods dealing with it enables the realization of various spatial essences. Second, the ontological event-system is required for the formation of relationship among beings. He tried to create a spatial meaning by introducing external environment into the inside and using the materials reflecting regional features and phenomenological empiricism through the multisensory experience. Third, he applied assimilation/insert/adjustment/formative change as the way of constructing the relationship between site and structure.