• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.296-298
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• 2015

자율적인 행위자들로서 서로 영향을 끼치며 상호작용하는 선박들을 관제하는 VTSO는 불확실성으로 인한 위험을 극복하기 위해서는 적극적으로 상황을 파악하여 최선의 의사결정을 하여야 한다. VTSO는 항상 미래의 상황을 예측하면서 업무를 수행하여야 하는데 이때 VTSO에게 요구되는 것이 바로 시뮬레이션 능력이다. 시뮬레이션은 삽화기억의 구성적 성격을 활용하는 것으로서 삽화기억의 메커니즘은 미래 계획에도 그대로 활용된다. 본고에서는 반사실적 사고가 시뮬레이션에 어떻게 작동되는가를 살펴보고, VTS 상황에 이를 적용하여 보았다. 특히 반사실적 사고와 시뮬레이션을 통해서 VTSO가 업무역량을 향상시키기 위해서 어떻게 학습하여야 하는가를 고찰하였다.

• The Korean Journal of Financial Management
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• v.19 no.2
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• pp.159-185
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• 2002

한 시계열이 비정상적과정에 의해 생성될 때 이 시계열의 정상성을 확보하기 위하여 시계열의 차분을 수행한다. 이 시계열에 I(1)을 적용하여도 정상적과정이 되지 못하는 경우가 존재하고 있다. 그러면 이 시계열은 과도한 차분과정을 거치게 된다. 따라서 차분모수 d는 0

• 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.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.16-22
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• 2019

Objectives: The objective of this study was to investigate the correlation between insufficient sleep and visuospatial memory in adolescents using a computerized neurocognitive function test. Methods: A total of 103 high school students (26 males and 77 females; mean age $17.11{\pm}8.50years$) without a serious psychiatric problem was recruited. All subjects were requested to complete a self-report questionnaire about weekday total sleep time and weekend total sleep time. The epworth sleepiness scale (ESS) and the beck depression inventory (BDI) were administered to measure daytime sleepiness and symptoms of depression. Seven subsets of the Cambridge Neuropsychological test automated battery were examined to assess visuospatial memory. Results: After controlling for age, sex, ESS, and BDI, longer weekend total sleep time was correlated with poor performance on delayed matching to sample (r = -0.312, p = 0.002) and immediate recall on pattern recognition memory (r = -0.225, p = 0.025). Increased weekend catch-up sleep time was correlated with poor performance of delayed matching to sample (r = -0.236, p = 0.018), immediate recall on pattern recognition memory (r = -0.220, p = 0.029), and delayed recall on pattern recognition memory (r = -0.211, p = 0.036) after controlling for age, sex, ESS, and BDI. Conclusion: This study showed that increased weekend catch-up sleep time reflecting insufficient weekday sleep were associated with poor performance in delayed recall tasks of visual memory. This finding suggests that insufficient sleep during adolescence might produce a decline of visuospatial memory.

• Korean Journal of Cognitive Science
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• v.19 no.4
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• pp.369-396
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• 2008

The purpose of this article is to investigate the effect of visual working memory, the types and contents of graphic annotations on English learning. The participants of the experiments were 5th and 6th graders. The result showed that animation was effective only in the word test for children with large visual working memory, whereas text-only-annotation yielded better performance in the comprehension test in Experiment 1. The effect of relevance of animations was tested in Experiment 2. Context-relevant-animations yielded better comprehension than the animations denoting the typical meaning, whereas the opposite pattern was reported in the word test. The result of the two experiments was interpreted in terms of cognitive load theory and the generative theory of multimedia learning.

• Environmental and Resource Economics Review
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• v.19 no.3
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• pp.485-508
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• 2010

This paper examines the long memory property and investigates cointegration in the dynamics of crude oil markets. For these purposes, we apply the joint ARMA-FIAPARCH model with structural break and the vector error correction model (VECM) to three daily crude oil prices: Brent, Dubai and West Texas Intermediate (WTI). In all crude oil markets, the property of long memory exists in their volatility, and the ARMA-FIAPARCH model adequately captures this long memory property. In addition, the results of the cointegration test and VECM estimation indicate a bi-directional relationship between returns and the conditional variance of crude oil prices. This finding implies that the dynamics of returns affect volatility, and vice versa. These findings can be utilized for improving the understanding of the dynamics of crude oil prices and forecasting market risk for buyers and sellers in crude oil markets.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.854-862
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• 2014

Attention deficit hyperactivity disorder (ADHD) students' intellctual defects, learning problems, and poor academic achievements seem to be due to significantly lower intelligence compared to the normal students, but rather the characteristic of inability to pay attention at a given time can be seen as the more attributing reason. In this study, a comparison between the ADHD students and the normal students will be performed using a fMRI analysis in order to differentiate the brain function between the two groups during a working memory task performance and to assess the difference in the activated regions of the brain. Clinical survey examinations and fMRI measurements were performed for a group of 26 elementary students from the Incheon area. The stimulus of fMRI was a working memory. Cartography statistically analyzed parameters and the Statistical Package of Social Sciences using single-sample t-test, two-sample t-test, were analyzed by multiple regression analysis, the statistical significance level was p<0.05 in, respectively. The disproportionate developments could be seen in the ADHD students group such as the frontal cortex, parietal cortex, thalamus, and caudate nucleus, among others. In addition, as some students felt the increase in the difficulty of working memory task performance, the orbitofrontal cortex and the hippocampus were activated, which seems to be the result of an effort for looking for an answer. More types of ADHD students needs to be secured as research subjects, and more stimulations for fMRI experiments should be considered as it would be useful in the overall evaluation of brain function.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.172-174
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• 2001

침입 탐지란 컴퓨터와 네트워크 지원에 대한 유해한 침입 행동을 식별하고 대응하는 과정이다. 점차적으로 시스템에 대한 침입 유형들이 복잡해지고 전문적으로 이루어지면서 빠르고 정확한 대응을 할 수 있는 시스템이 요구되고 있다. 이에 따라, 대용량의 데이터를 지능적으로 분석하여 의미있는 정보를 추출하는 데이터 마이닝 기법을 적용함으로써 지능적이고 자동화된 탐지를 수행할 수 있도록 한다. 본 논문에서는 학습 데이터를 각각 사례로 데이터베이스에 저장한 후, 실험 데이터가 입려되면 가장 가까운 거리에 있는 학습 데이터의 크래스로 분류하는 사례 기반 학습을 이용하여 빠르게 사용자의 이상 행위에 대해 판정한다. 그러나 많은 사례로 인해 기억 공간이 늘어날 경우 시스템의 성능이 저하되는 문제점을 고려하여, 빈발 에피소드 알고리즘을 수행하여 발견한 순차 패턴을 사례화하여 정상 행위 프로파이로 사용하는 순차패턴에 대한 사례 기반 학습을 제안한다. 이로써, 시스템 성능의 저하율을 낮추고 빠르며 정확하게 지능적인 침입 탐지를 수행할 수 있다.

• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.3-18
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• 2015

Numerosity perception is considered as an innate ability of human being where its sensivitiy may widely vary across each individual person. The present study explored the relationship between visual working memory (VWM), visual search efficiency, and numerosity sensitivity. To accomplish this, we calculated each participant's K-value from change detection performance representing one's storage capacity in VWM, slopes of search RTs representing the search efficiency, and discrimination sensitivity for a quantity difference across two sets of dot arrays representing the numerosity sensitivity. The correlational analysis across the measurements revealed that participants with a high VWM capacity better discriminated the numerosity difference in the arrays when the spatial information in the two dot arrays was preserved. In contrast, the participants with high search efficiency discriminated better the difference in the arrays when the spatial information in the arrays was not preserved. The results indicate high VWM-capacity individuals were presumably able to use a strategy of storing the dot arrays by grouping them into a smaller pattern of dot arrays while high search-efficiency individuals were able to use a strategy of rapidly switching their focused attention across the dots in the arrays to count each individual dot. These in sum suggest that individual differences in numerosity sensitivity rely on one's working memory capacity as well as their efficient use of switching focused attention.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.311-320
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• 2021

At present, the secondary school teacher employment examination(SSTEE) is the only gateway to become a national and public secondary teacher in Korea, and after the revision from the 2014 academic year, all the questions of the exam have been converted to supply-type test items, requiring more definitive, accurate, and solid answers. Compared to the selection-type test items that measure recognition memory, the supply-type questions, testing recall memory, require constant memorization and retrieval practices to furnish answers; however, there is not enough learning tools available to support the practices. At this juncture, this study invented a mobile app, called ONE PASS, for the SSTEE. By unpacking the functional mechanisms of the brain, the basis of cognitive processing, this ONE PASS app offers a set of tools that feature brain-based learning principles, such as a personalized study planner, motivation measurement scales, mind mapping, brainstorming, and sample questions from previous tests. This study is expected to contribute to the research on the development of learning contents for applications, and at the same time, it hopes to be of some help for candidates in their exam preparation process.