• 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.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.2
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• pp.103-116
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• 2017

In this paper, we present the design and implementation of a large-scale qualitative spatial reasoner, which can derive new qualitative spatial knowledge representing both topological and directional relationships between two arbitrary spatial objects in efficient way using Aparch Spark SQL. Apache Spark SQL is well known as a distributed parallel programming environment which provides both efficient join operations and query processing functions over a variety of data in Hadoop cluster computer systems. In our spatial reasoner, the overall reasoning process is divided into 6 jobs such as knowledge encoding, inverse reasoning, equal reasoning, transitive reasoning, relation refining, knowledge decoding, and then the execution order over the reasoning jobs is determined in consideration of both logical causal relationships and computational efficiency. The knowledge encoding job reduces the size of knowledge base to reason over by transforming the input knowledge of XML/RDF form into one of more precise form. Repeat of the transitive reasoning job and the relation refining job usually consumes most of computational time and storage for the overall reasoning process. In order to improve the jobs, our reasoner finds out the minimal disjunctive relations for qualitative spatial reasoning, and then, based upon them, it not only reduces the composition table to be used for the transitive reasoning job, but also optimizes the relation refining job. Through experiments using a large-scale benchmarking spatial knowledge base, the proposed reasoner showed high performance and scalability.

• Korean Journal of Remote Sensing
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• v.17 no.1
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• pp.57-69
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• 2001

This study propose a image processing system of unsupervised analysis. This system integrates low-level segmentation and high-level classification. The segmentation and classification are conducted respectively with and without spatial constraints on merging by a hierarchical clustering procedure. The clustering utilizes the local mutually closest neighbors and multi-window operation of a pyramid-like structure. The proposed system has been evaluated using simulated images and applied for the LANDSATETM+ image collected from Youngin-Nungpyung area on the Korean Peninsula.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.351-360
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• 2016

The purpose of this study is to predict visual-spatial working memory performance through the characteristics of an electroencephalogram (EEG) in the resting state. The 31 study participants, middle school students with various to academic performance, were underwent visual-spatial working memory test in the Comprehensive Attention Test (CAT) on December in 2014. Each 7 and 6 participants were divided into an Excellent Working Memory (EWM) group and Poor Working Memory (PWM) group depending on the forward/backward working memory scores. The EEG measurements and analysis of the data from a Brain Function Tester were performed by the two groups. A Mann-Whitney Test was used to examine the statistical differences between them. The activation of high beta (${\beta}H$) at the Fp1 and Fp2 sites in the left and right hemisphere, and that of the low beta (${\beta}L$) in the right hemisphere in the EWM group was significantly higher than that in the PWM group. In conclusion, there is a correlation between the visual-spatial working memory performance and the activation of ${\beta}H$ and ${\beta}L$ in the resting state and a close correlation that of ${\beta}L$ in the right hemisphere in terms of mental activity and faculty. Therefore, the visual-spatial working memory performance can be predicted by the activation of ${\beta}H$ and ${\beta}L$ in the resting state. The activation of EEG can be applied as an assessment tool and provide basis data for visual-spatial working memory performance.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.169-171
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• 2002

최근 사용자가 언제 어디서나 원하는 정보에 접근을 요구하는 경향이 증가하고 있다. 이동 단말은 기억공간의 제약으로 인해 원하는 데이터 전부를 저장할 수 없으므로, 무선망을 통해 서버에 연결하여 자신이 필요한 데이터를 요구하게 된다. 효율적인 이동 컴퓨팅을 위해서는 네트워크 단절 시에도 작업을 지속적으로 수행할 수 있도록 하는 기능이 제공되어야 한다. 한편 컴퓨터와 통신 네트워크의 발달이 가속화되며 그에 따른 인터넷과 웹의 사용이 급속히 확산됨에 따라 이동 중의 작업에 대한 요구가 증가하고 있다. 본 논문에서는 기존에 연구된 이동 컴퓨팅 환경에서 연결 단절을 위한 다양한 자동 저장 방식들을 이동 인터넷 환경에 적용한 구조를 제안하였다. 특히 사용자의 요구는 시간에 따라 변할 수 있음을 고려하여 time weighting factor를 이용한 자동 저장 방식을 제안하고 시뮬레이션을 수행하였다.

• The Journal of Korean society of community based occupational therapy
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• v.8 no.3
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• pp.69-76
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• 2018

Objective : The study was to investigate the neurophysiological approach to the effect of complex exercise on memory, one of brain functions, and the degree of sleep disorder using experimental animals with sleep disorders. Methods : This study carried out a complex exercise that designed in an animal laboratory for 4 days to 16 sleep - disordered model rats. After the exercise, brain function was confirmed with the changes of BDNF in the hippocampus and the change of sleep level was confirmed with the concentration of melatonin in the blood. Results : First, the effect of the complex exercise program on brain function was significantly increased in the experimental group(p<0.01). Second, the effect of complex exercise program on sleep disturbance was significantly increased in the experimental group and control group(p<0.01)(p<0.05). Conclusion : The rate of increase of the elderly in the community is rapidly increasing, and the sleep disorder of the elderly can affect the quality of life of these elderly people. Secondary memory impairment due to sleep disturbances can also be a problem. Although there are many ways to improve sleep disturbance, it has been scientifically proven through experimental animals that sleep and memory can be improved with complex exercise that is not economically, spatially burdensome.

• Korean Journal of Schizophrenia Research
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• v.15 no.2
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• pp.66-72
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• 2012

Objectives : The aim of this study was to investigate whether verbal and spatial working memory functions were impaired not only in patients with schizophrenia but also in people at ultra-high risk for first-episode psychosis. Methods : Twenty-five patients (M 13, F 12) with schizophrenia (SPR), 21 people at ultra-high risk for psychosis (UHR)(M 10, F 11) and 19 normal controls (NC)(M 10, F 9) were recruited. The working memory was assessed by using the verbal and spatial n-back test. The working memory load increased incrementally from the 0-back to the 3-back condition. Results : SPR performed significantly lower than NC and UHR in terms of hit rates of verbal and spatial n-back test. UHR subjects conducted significantly lower than NC and higher in trend-level than SPR in terms of hit rates of verbal and spatial n-back test. These differences were derived from the high working memory load (2-back and 3-back), not from the low working memory load (0-back and 1-back). There was no significant difference between the verbal and spatial n-back test across the three groups. Conclusion : These findings suggest that verbal and spatial working memory dysfunction may be general rather than differential in terms of stimuli modality, and this working memory deficit may be an important trait factor in schizophrenia.

• Journal of The Korean Association For Science Education
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• v.41 no.5
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• pp.371-390
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• 2021

The purpose of this study is to develop a neuropsychological model for the spatial ability factor and to divide the brain active area involved in the light & shadow problem solving process into the domain-general ability and the domain-specific ability based on the neuropsychological model. Twenty-four male college students participated in the study to measure the synchronized eye movement and electroencephalograms (EEG) while they performed the spatial ability test and the light & shadow tasks. Neuropsychological model for the spatial ability factor and light & shadow problem solving process was developed by integrating the measurements of the participants' eye movements, brain activity areas, and the interview findings regarding their thoughts and strategies. The results of this study are as follows; first, the spatial visualization and mental rotation factors mainly required activation of the parietal lobe, and the spatial orientation factor required activation of the frontal lobe. Second, in the light & shadow problem solving process, participants use both their spatial ability as a domain-general thought, and the application of scientific principles as a domain-specific thought. The brain activity patterns resulting from a participants' inferring the shadow by parallel light source and inferring the shadow when the direction of the light changed were similar to the neuropsychological model for the spatial visualization factor. The brain activity pattern from inferring an object from its shadow by light from multiple directions was similar to the neuropsychological model for the spatial orientation factor. The brain activity pattern from inferring a shadow with a point source of light was similar to the neuropsychological model for the spatial visualization factor. In addition, when solving the light & shadow tasks, the brain's middle temporal gyrus, precentral gyrus, inferior frontal gyrus, middle frontal gyrus were additionally activated, which are responsible for deductive reasoning, working memory, and planning for action.

• 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.

• The Korean Journal of Archival Studies
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• no.36
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• pp.233-269
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• 2013

This study aims to explore practicable and sustainable strategies for locality documentation through networking, linking, and recontextualization of records in digital environments. It applies the 'spanDoc(SPAace-based Networked Documentation) Model to document Donghae-Nambu Railway areas placed in Busan Metropolitan City tentatively. Considering that mobility and openness are the main characteristics of Busan, railway areas and their stations can be proper places for representing such localities of the city. Moreover, there can be much experiences and memories of residents surrounding those areas, because Donghae-Nambu Railway has been used as short distance transportation facilities across the inner city of Busan since 1930's. This study tries to implement the documentation strategy for the selected space, following the procedures of the spanDoc Model. Firstly, this study develops the structure of the subjects through investigating the related information sources and archives from various collecting institutions. Secondly, it carries out records surveys to identify the essential records types for documenting the Donghae-Nambu Railway areas. Thirdly, it describes the subjects and sub-subjects, and the entries of places, people and subjects for adding to the dictionaries. Finally, it links many entities such as subjects, records, and dictionary, and builds the databases regarding the inter-links and systematic accumulation of the outputs of each step.