• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.499-501
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• 2003

As semiconductor memory becomes cheaper, the memory capacity of computer system is increasing. Therefore computer system has sufficient memory for a plentiful spatial data. With emerging spatial application required high performance, this paper presents a GIS database system in main memory. Memory residence can provide both functionality and performance for a database management system. This paper describes design of DBMS for storing, querying, managing and analyzing for spatial and non-spatial data in main-memory. This memory resident GIS DBMS supports SQL for spatial query, spatial data model, spatial index and interface for GIS tool or applications.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.133-142
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• 2009

Recently, with the advance of wireless internet and the frequent use of mobile devices, demand for LBS(Location Based Service) is increasing, and research is required on spatial indexes for the storage and maintenance of spatial data to provide efficient LBS in mobile device environments. In addition, the use of flash memory as an auxiliary storage device is increasing in order to store large spatial data in a mobile terminal with small storage space. However, the application of existing spatial indexes to flash-memory lowers index performance due to the frequent updates of nodes. To solve this problem, research is being conducted on flash-memory based spatial indexes, but the efficiency of such spatial indexes is lowered by low utilization of buffer and flash-memory space. Accordingly, in order to solve problems in existing flash-memory based spatial indexes, this paper proposed FR-Tree (Flash-Memory based R-Tree) that uses the node compression technique and the delayed write operation technique. The node compression technique of FR-Tree increased the utilization of flash-memory space by compressing MBR(Minimum Bounding Rectangle) of spatial data using relative coordinates and MBR size. And, the delayed write operation technique reduced the number of write operations in flash memory by storing spatial data in the buffer temporarily and reflecting them in flash memory at once instead of reflecting the insert, update and delete of spatial data in flash-memory for each operation. Especially, the utilization of buffer space was enhanced by preventing the redundant storage of the same spatial data in the buffer. Finally, we perform ed various performance evaluations and proved the superiority of FR-Tree to the existing spatial indexes.

• The Journal of Korean society of community based occupational therapy
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• v.9 no.2
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• pp.13-22
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• 2019

Objective : The purpose of this technical research is to determine decline of episodic memory by normal aging focucing on object, spatial location, and temporal order memory. Methods : We allocated seventy-seven of healthy adults from twenty to eighty years old, and performed computer-based cognitive tasks which were consisted of the object, spatial location, and temporal order memory. We used OpenSesame(OpenSesame Inc, OR), put ten pictures people normally see in their daily life, and evaluated those aspects through asking the objects types, object spatial locations, and picture temporal orders from 10 sheets of the picture. Results : Object and spatial location memory were not affected by normal aging whereas, temporal order memory significantly decreased with normal aging. Specifically, temporal order memory for in their age of forty was significantly decreased compared with their age of twenty and object memory at their age of eighty was relatively high compared to spatial location and temporal order memory. We found out that temporal order memory worse fastest and object memory lasted longest. Conclusion : In this study, we confirmed characteristics of declines of episodic memory consisting of object, spatial location, and temporal order memory. Notably, we could specifically identify declines of spatial location and temporal order memory with normal aging previous studies investigated on a limited basis using conventional neuropsychological assessments. These findings would be helpful to screen impairment in episodic memory by normal aging and provide an evidence that cognitive intervention for healthy older adults needs to include spatial and temporal aspect of memory.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.11-22
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• 2004

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per you. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules： the interface manager provides the interface for PDA users； the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques； the query manager processes spatial and non-spatial query : the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index : the GIS server interface provides the interface with disk-based GIS. The MR-tree proposed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimensional MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memory techniques, the memory data manager uses page tables for spatial data, non- spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

• Korean Journal of Child Studies
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• v.20 no.3
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• pp.293-306
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• 1999

This study investigated children's spatial skills and short term memory ability based on their practice with computer games. The 40 four-year-old and 40 six-year-old subjects were divided by experimental and control groups. Spatial skills of children were assessed by visual speed, mental rotation, and spatial visualization tasks. Short term memory was measured with a digit span task. Results showed that computer game practice enhanced children's memory ability and spatial skills. Even 4-year-olds performed better on mental rotation and spatial visualization tasks after practice. The treatment effect was significant for visual speed of 6-year-olds, short term memory ability and mental rotation of 4-year-olds, and spatial visualization of both 4- and 6-year-olds.

• Korean Journal of Cognitive Science
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• v.10 no.4
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• pp.41-50
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• 1999

It is widely known that the hippocampus plays an important role in spatial memory. Recent studies have suggested that the posterior parietal cortex (PPC) is involved in spatial memory. However it is unclear whether the PPC is involved in w working memory or reference memory of spatial learning. The purpose of the present study was to determine contribution of the hippocampus and the PPC to spatial working memory and acquisition of reference memory. Using an eight-arm radial maze in which e each arm was baited. working memory was tested by measuring rat's ability to remember arms they had visited. Reference memory was tested by measuring rat's ability to avoid visiting four consistently unbaited arms. Effects of hippocampal or PPC lesion on working memory or acquisition of reference memory in radial-arm maze learning were investigated Working memory was impaired by hippocampal lesion whereas not affected by PPC lesion. Acquisition of reference memory was impaired by lesion in either site. The results suggest that the hippocampus plays an important role in the spatial working memory while both the hippocampus and the PPC contribute to the acquisition of spatial reference memory.

• The Journal of Korean Medicine
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• v.38 no.2
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• pp.31-40
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• 2017

Objectives: We investigated the effect of acupuncture on memory function in relation with neurogenesis in old rats. Methods: In this study, a step-down avoidance task for short-term memory and Y-maze task for spatial memory capability were conducted. Western blot analysis for brain-derived neurotorphic factor (BDNF) and tyrosine kinase B (TrkB), and immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU) were performed. Results: Short-term memory and spatial memories were decreased in the old-aged rats. Expressions of BDNF and TrkB in the hippocampus were significantly decreased in the old-aged rats. Neurogenesis in the hippocampal dentate gyrus was also decreased in the old-aged rats. However, acupuncture treatment alleviated impairment of short-term and spatial memories induced by ageing. Acupuncture also increased the expressions of BDNF and TrkB and enhanced neurogenesis in the hippocampus. The present study showed that acupuncture alleviated ageing-induced short-term and spatial memory loss by increasing of BDNF and neurogenesis. Acupuncture at ST41-acupoint showed most potent effect than at ST36-acupoint or non-acupoint. Conclusions: Acupuncture might be used as the effective therapeutic modality to ameliorate the age-related decrease of brain functions.

• Korean Journal of Cognitive Science
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• v.19 no.2
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• pp.125-142
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• 2008

This study investigated the effects of space- and object-based attention on spatial and visual working memory, by measuring recognition of working memory on the spatial Stroop task including two modalities of attention resource. The similarity condition of stimulus arrangement between working memory task and spatial stroop task was manipulated in order to examine the effects of space-based attention on spatial rehearsal during working memory task, while Stroop rendition was manipulated in order to examine the effects of object-based attention on object rehearsal during working memory task. The results showed that in a condition that stimulus arrangement was highly similar for the spatial working memory task and the spatial Stroop task, recognition accuracy of the spatial working memory was high, but it was not significantly different with the Stroop conditions. In contrast, the recognition accuracy of visual working memory in the incongruent Stroop condition was lower than that in the congruent Stroop condition, but it was not significantly different with the similarity conditions (25% vs. 75%). The results indicated that selective attention has effects on working memory only when resource modality of working memory is the same as that of selective attention.

• Research in Vestibular Science
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• v.17 no.4
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• pp.134-141
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• 2018

Objectives: We aimed to study the role of vestibular input on spatial memory performance in mice that had undergone bilateral surgical labyrinthectomy, semicircular canal (SCC) occlusion and 4G hypergravity exposure. Methods: Twelve to 16 weeks old ICR mice (n=30) were used for the experiment. The experimental group divided into 3 groups. One group had undergone bilateral chemical labyrinthectomy, and the other group had performed SCC occlusion surgery, and the last group was exposed to 4G hypergravity for 2 weeks. The movement of mice was recorded using camera in Y maze which had 3 radial arms (35 cm long, 7 cm high, 10 cm wide). We counted the number of visiting arms and analyzed the information of arm selection using program we developed before and after procedure. Results: The bilateral labyrinthectomy group which semicircular canal and otolithic function was impaired showed low behavioral performance and spacial memory. The semicircular canal occlusion with $CO_2$ laser group which only semicircular canal function was impaired showed no difference in performance activity and spatial memory. However the hypergravity exposure group in which only otolithic function impaired showed spatial memory function was affected but the behavioral performance was spared. The impairment of spatial memory recovered after a few days after exposure in hypergravity group. Conclusions: This spatial memory function was affected by bilateral vestibular loss. Space-related information processing seems to be determined by otolithic organ information rather than semicircular canals. Due to otolithic function impairment, spatial learning was impaired after exposure to gravity changes in animals and this impaired performance was compensated after normal gravity exposure.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.5
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• pp.632-638
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• 2005

This paper describes a new data-handing, based on a Spatial Human Interface as human indicator, to the Spatial-Knowledge-Tags (SKT) in the spatial memory the Spatial Human Interface (SHI) is a new system that enables us to facilitate human activity in a working environment. The SHI stores human activity data as knowledge and activity history of human into the Spatial Memory in a working environment as three-dimensional space where one acts, and loads them with the Spatial-Knowledge-Tags(SKT) by supporting the enhancement of human activity. To realize this, the purpose of SHI is to construct new relationship among human and distributed networks computers and sensors that is based on intuitive and simultaneous interactions. In this paper, the specified functions of SKT and the realization method of SKT are explained. The utility of SKT is demonstrated in designing a robot motion control.