• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.359-386
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• 2010

In order to evaluate the domain-specific model and process-specific model of spatial and nonspatial working memory (WM), this study manipulated the memory load of the delayed response task and examined how the neural correlates of memory load effect was influenced by the stimulus domain (face and location) at the maintenance stage of WM using an event-related fMRI experiment. One or three face stimuli were presented as target stimuli and participants were asked to maintain the face itself (face WM) or the location of face stimuli (spatial WM). The results of recognition judgment accuracy showed no difference between face WM and spatial WM, and showed equivalent memory load effects of both WM. As a result of brian image analysis, memory load effect at maintenance stage showed that inferior, middle, and superior PFC were recruited by both face WM and spatial WM, and showed that VLPFC was the commonly activated area by both WM, supporting functional specialization of PFC by process components of WM. This study provides evidence for process-specific model in which maintenance of WM is associated with VLPFC.

• Korean Journal of Cognitive Science
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• v.16 no.3
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• pp.155-174
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• 2005

Oh and Kim (2004) and Woodman and Lurk (2004) demonstrated that spatial working memory (SWM) load Interfered concurrent visual search and that search process also impaired the maintenance of spatial information implying that visual search and SWM task both require access to the same limited-capacity mechanism. Two obvious possibilities have been suggested about what this shared limited-capacity mechanism is: common demand for attention to the locations where the items f9r the two tasks were presented (spatial attention load hypothesis), and common use of working memory to maintain a record of locations have been processed(SWM load hypothesis). To test these two hypothetical explanations, Experiment 1 replicated the mutual interference between visual search and SWM task in spite of difference of procedure with preceding researches; possible areas where the items for two tasks were presented were not separated. In Experiment 2, we presented the items for visual search either in the same quadrants where the items for SWM task had appeared (same-location rendition) or in the different quadrants (different-location condition). As a result, search efficiency was more impaired in the different-location condition than in the same-location condition. The memory accuracy was worse in the different-location rendition than in the same-location rendition. Overall results of study indicate that the mutual interference between SWM and visual search might be related to the overload of spatial attention, but not to that of SWM.

• 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.

• 한국노년학
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• v.36 no.4
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• pp.1109-1124
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• 2016

We examined the effect of stereotype threat (STT) on spatial working memory and facial emotion recognition in Korean elderly. In addition, we investigated the role of expected moderator such as self-perception of aging. Seventeen seniors (male=7) received basic cognitive tests including K-WMS-IV, MMSE and answered self-report questionnaires including self-perception of aging, anxiety of aging, attitude toward aging and age identity on the first visit. On the second visit, they were exposed to negative stereotype by reading a script detailing cognitive decline related to aging while a control group was exposed to a neutral content. Following the exposure, they were tested on a spatial-working memory task (Corsi-block tapping task) and emotion recognition task (facial expression identification task). The results showed that the seniors exposed to STT showed significantly lower performance on emotion recognition task (p < .05) (i.e., especially on the more difficult facial stimuli). In addition, there was a significant interaction between STT and self-perception of aging (p< .05), indicating that those who have positive self-perception of aging did not show impairment in emotion recognition task and difficult spatial working memory task under STT. On the other hand, those with negative self-perception of aging showed impaired performance under STT. Taken together, the current study suggests that being exposed to STT could negatively influence cognitive and emotional functioning of elderly. Interestingly, having a positive self-perception of aging could protect the underperformance caused by STT.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.779-781
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• 2003

최근에 제안된 VA-File［6］은 k-NN 질의 처리에서 아주 효율적이라고 알려져 있다. 제시된 방법은 분할된 데이터의 저장 효율성을 보장하지 못하기 때문에 각 차원에 할당된 비트의 수가 증가하면(비트수＝3~5) 할수륵 거의 모든 데이터에 대하여 MBH를 생성하는 단점이 있다. k-NN 질의는 거의 모든 데이터를 순차 검색을 통한 일차적 가지제거작업을 한 후. 질의를 수행하기 위한 디스크 접근을 한다. 따라서, 질의를 수행하기 위한 디스크 접근 횟수는 다른 방법들에 비하여 거의 최적에 가까운 접근 횟수를 가지나 주 기억 장치에서 최소-힘을 이용하여 수행하는 일차적 가지 제거 작업의 오버 로더는 간과되었다. 우리는 기존에 알려진 재귀적으로 공간을 두개의 부 공간으로 분할하는 방법을 사용하여 VA-File 과 같은 디렉토리 자료구조를 구축하여 k-NN 실험을 하였다. 이러한 분할된 MBH의 정방형성을 선호하는 방법은 저장 효율성을 보장한다. 실제 데이터에 대한 실험에서 우리가 실험한 간단한 방법은 디스크 접근 시간 및 CPU 시간을 합한 전체 수행시간에서 VA-File에 비하여 최대 93% 정도의 성능 향상이 있다.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.225-237
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• 1998

Purpose: We investigated the statistical methods to compose the functional brain map of human working memory and the principal factors that have an effect on the methods for localization. Materials and Methods: Repeated PET scans with successive four tasks, which consist of one control and three different activation tasks, were performed on six right-handed normal volunteers for 2 minutes after bolus injections of 925 MBq $H_2^{15}O$ at the intervals of 30 minutes. Image data were analyzed using SPM96 (Statistical Parametric Mapping) implemented with Matlab (Mathworks Inc., U.S.A.). Images from the same subject were spatially registered and were normalized using linear and nonlinear transformation methods. Significant difference between control and each activation state was estimated at every voxel based on the general linear model. Differences of global counts were removed using analysis of covariance (ANCOVA) with global activity as covariate. Using the mean and variance for each condition which was adjusted using ANCOVA, t-statistics was performed on every voxel To interpret the results more easily, t-values were transformed to the standard Gaussian distribution (Z-score). Results: All the subjects carried out the activation and control tests successfully. Average rate of correct answers was 95%. The numbers of activated blobs were 4 for verbal memory I, 9 for verbal memory II, 9 for visual memory, and 6 for conjunctive activation of these three tasks. The verbal working memory activates predominantly left-sided structures, and the visual memory activates the right hemisphere. Conclusion: We conclude that rCBF PET imaging and statistical parametric mapping method were useful in the localization of the brain regions for verbal and visual working memory.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.79-82
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• 2019

본 논문은 VR을 기반으로 하여 별도의 장갑이나 핸드헬드 디바이스 없이 치매 예방과 재활치료를 위한 VR을 이용함으로써 사용자의 두뇌 사용능력과 신체 활동성을 증가시켜 치매예방과 재활치료 효과를 향상시킬 수 있도록 하였다. 치매 예방 콘텐츠로는 치매의 대표적인 원인인 뇌세포의 퇴화에 초점을 맞춰 기억력, 논리력, 산술능력, 공간인지능력 등을 훈련할 수 있도록 구성하고, 노인을 위한 재활치료 콘텐츠로는 상지훈련, 하지훈련, 정신훈련, 밸런스훈련 등에 효과적이도록 구성하였다. 1:N 방식의 그룹훈련으로 고도화하여 다수의 사용자 또는 그룹이 작업치료사 한 명의 통제를 받아 치매예방 및 인지훈련이 가능한 시스템 개발하고 공공보건의료시설, 요양원, 재활의학과 보유병원 등에서 이용할 수 있다.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.225-233
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• 2012

The 3D stereoscopic image contents have been emerging as the blue chip of the contents market of the next generation since the . However, all the 3D contents created commercially in the country have failed to enter box office. It is because the quality of Korean 3D contents is much lower than that of overseas contents and also current 3D post production process is based on 2D. Considering all these facts, the 3D editing process has connection with the quality of contents. The current 3D editing processes of the production case of are using the way that edits with the system on basis of 2D, followed by checking with 3D display system and modifying, if there are any problems. In order to improve those conditions, I suggest that the 3D editing process contain more objectivity by visualizing the depth data applied in some composition work such as Disparity map, Depth map, and the current 3D editing process. The proposed process has been used in the music drama , comparing with those of the film . The 3D values could be checked among cuts which have been changed a lot since those of , while the 3D value of drew an equal result in general. Since the current process is based on an artist's subjective sense of 3D, it could be changed according to the condition and state of the artist. Furthermore, it is impossible for us to predict the positive range, so it is apprehended that the cubic effect of space might be perverted by showing each different 3D value according to cuts in the same space or a limited space. On the other hand, the objective 3D editing by applying the visualization of depth data can adjust itself to the cubic effect of the same space and the whole content equally, which will enrich the 3D contents. It will even be able to solve some problems such as distortion of cubic effect and visual fatigue, etc.