• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.491-496
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• 2024

The purpose of this study is to examine the effects of leisure satisfaction on cognitive function and to examine mediating effect of social network in the relationship between leisure satisfaction and cognitive function of older adults. For this, this study utilized 2023 Social Survey data and 9,526 older adults aged over 65 years were analyzed. Study results showed that first, leisure satisfaction had positive effects on cognitive function of older adults. Second, social network had positive effects on cognitive function of older adults. Third, leisure satisfaction of the elderly had effects on cognitive function mediated by social network. That is, older adults with higher level of leisure satisfaction had more number of social network leading to a higher level of cognitive function. Results of this study show that leisure activities can be considered in maintaining and improving cognitive function of older adults and there is a need to promote types of leisure activities which extend social network.

• Journal for History of Mathematics
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• v.22 no.3
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• pp.31-44
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• 2009

Anyone wishing to understand cognitive science, a converging science, need to become familiar with three major mathematical landmarks: Turing machines, Neural networks, and $G\ddot{o}del's$ incompleteness theorems. The present paper aims to explore the mathematical foundations of cognitive science, focusing especially on these historical landmarks. We begin by considering cognitive science as a metamathematics. The following parts addresses two mathematical models for cognitive systems; Turing machines as the computer system and Neural networks as the brain system. The last part investigates $G\ddot{o}del's$ achievements in cognitive science and its implications for the future of cognitive science.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.213-216
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• 2018

본 논문에서는 사람의 인지 시각 특성 중 하나인 JND(Just Noticeable Difference)를 이용한 인지 비디오 부호화 기법을 제안한다. JND 기반 인지 부호화 방법은 사람의 인지 시각 특성을 이용해 시각적으로 인지가 잘 되지 않는 인지 신호를 제거함으로 부호화 효율을 높이는 방법이다. 제안된 방법은 기존 수학적 모델 기반의 JND 기법이 아닌 최근 각광 받고 있는 데이터 중심(data-driven) 모델링 방법인 심층 신경망 기반 JND 모델 생성 기법을 제안한다. 제안된 심층 신경망 기반 JND 모델은 비디오 부호화 과정에서 입력 영상에 대한 전처리를 통해 입력 영상의 인지 중복(perceptual redundancy)를 제거하는 역할을 수행한다. 부호화 실험에서 제안된 방법은 동일하거나 유사한 인지화질을 유지한 상태에서 평균 16.86 %의 부호화 비트를 감소 시켰다.

• Journal of Advanced Navigation Technology
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• v.17 no.4
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• pp.435-441
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• 2013

This paper proposes a neural net based-predictive connection admission control (CAC) scheme for multiclass users in wireless cognitive radio networks. We classifies cognitive users(cu) into real and non real time services, and then permit only real time services to reserve the demanded resource for spectrum handoff in guard channel for provisioning the desired QoS. Neural net is employed to predict primary user's arrival on time and demanded channels. Resource scheduling scheme is based on $C_IA$(cognitive user I complete access) shown in this paper. For keeping primary users from interference, the CAC is performed on only cognitive user not primary user. Simulation results show that our schemes can guarantee the desired QoS by cognitive real time services.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.1-8
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• 2010

Wireless multimedia service through the access to mobile telephone network or data network is a vital part of contemporary life, and the demand for frequency spectrum for new services is expected to explode as the ubiquitous computing proliferate. Cognitive radio is a technology, which automatically recognizes and searches for temporally and spatially unused frequency spectrum, then actively determines the communication method, bandwidth, etc. according to the environment, thus utilizing the limited spectrum resources efficiently. In this paper, we investigate the effects of imperfect sensing, misdetection and false alarm, on the primary and secondary users' spectrum usage through the analysis of continuous time Markov Chain. We analyzed the effects of the parameters such as sensing error, offered load on the system performance.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.347-352
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• 2017

In this paper, we propose a method that reduces mobile user's handover call dropping probability by using cognitive radio technology(CR) in cellular - based wireless cognitive radio networks. The proposed method predicts a cell to visit by Ziv-Lempel algorithm, and then supports mobile user with prediction of spectrum holes based on CR technology when allocated channels are short in the cell. We make neural network predict spectrum hole resources, and make handover calls use the resources before initial calls. Simulation results show CR technology has the capability to reduce mobile user handover call dropping probability in cellular mobile communication networks.

• Annual Conference on Human and Language Technology
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• 1989.10a
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• pp.101-106
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• 1989

음성 및 문자를 통한 컴퓨터와의 정보 교환을 위한 통합 사용자 인터페이스 (Intelligent Man- Machine interface) 시스템의 일환으로 한국어 단모음의 인식을 위한 시스템을 인공 신경망 모델을 사용하여 구현하였으며 인식시스템의 상위 접속부에 필요한 단어 인식 모듈에 있어서의 인지 실험도 행하였다. 모음인식의 입력으로는 제1, 제2, 제3 포르만트가 사용되었으며 실험대상은 한국어의 [아, 어, 오, 우, 으, 이, 애, 에]의 8 개의 단모음으로 하였다. 사용한 인공 신경망 모델은 Multilayer Perceptron 이며, 학습 규칙은 Generalized Delta Rule 이다. 1 인의 남성 화자에 대하여 약 94%의 인식율을 나타내었다. 그리고 음성 인식시의 인지 현상 실험을 위하여 약 20개의 단어를 인공신경망의 어휘레벨에 저장하여 음성의 왜곡, 인지시의 lexical 영향, categorical percetion등을 실험하였다. 이때의 인공 신경망 모델은 Interactive Activation and Competition Model을 사용하였으며, 음성 입력으로는 가상의 음성 피쳐 데이타를 사용하였다.

• The Journal of Korean society of community based occupational therapy
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• v.9 no.1
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• pp.25-34
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• 2019

Objective : The purpose of this study was to investigate the effect of cognitive level of mild cognitive impaired elderly living in the community on participation in activities and social networks as well as leisure and daily life activities. Methods : The elderly people aged 65 years or older living in the community were selected for the mild cognitive impairment with a score of MMSE-K of 15 or more and 23 or less. MoCA-K was applied in order to examine the cognitive abilities of the subjects and K-ACS and LSNS-18 were applied to confirm the activity participation level and social network index. Results : As a result of examining the relationship between cognition and activity participation, various sub-abilities(spatio-temporal abilities, vocabulary abilities, attention, abstract thinking) of cognition had a significant influence on instrumental activities of daily living, leisure activities and social activities. In addition, all of the sub - abilities of cognition showed a significant correlation with sub-elements of social network. Conclusion : Through this study, it was found that the general elements of cognition influenced activity participation and social network of various areas of mild cognitive impaired elderly people. We suggest that measures for enhancing participation and social participation of the elderly with mild cognitive impairment are provided through follow up studies.

• The Journal of Korean Association of Computer Education
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• v.8 no.6
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• pp.33-44
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• 2005

This study lets you know how semantic network programs called mind tools have an effect on students' learning achievements and learning motives regarded students' cognitive levels. It helps improve the education in the real situation of the classroom. It shows that the class applied by mind tools regarded transitional students' cognitive levels and motive strategies increases students' biologies-learning achievements because it improves students' concentration and confidence efficiently connected with new knowledge by using visual effects. Also, it shows that transitional students' semantic network learning is superior to students' in formal operation stage and it is effective in forming learning contents in the structural organization with students' knowledge.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.61-62
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• 2022

알츠하이머성 치매는 현존하는 치료법이 없어 경도인지장애 단계에서의 예방이 중요하다. 지금까지의 알츠하이머 연구는 대부분이 뇌영상 마커와 뇌척수액 마커에 집중되어 있었으며, 경도 인지 장애 단계에서의 탐색은 더욱 적었다. 이러한 점에서 혈액 유전자 발현을 이용한 경도 인지장애 단계 예측은 인지 능력에 따른 관련 유전자 식별과 접근 가능한 진단 및 치료 바이오 마커 탐색에 기여할 수 있다. 그러나 유전자 발현 데이터의 경우 환자 수에 비해 높은 차원을 가지기 때문에 과적합을 막고 질병 관련 유전자를 식별하기 위해서는 데이터에서의 의미 있는 차원만을 뽑아내는 차원 축소가 선행되야 한다. 본 연구는 유전자 발현데이터에서의 인지장애 분류를 위해 차원 축소기법과 신경망을 적용하여 인지 장애 정도를 예측하였다. 그 결과, Lasso 이용 차원축소와 신경망을 이용하여 97%의 정확도로 정상과 조기 경도 인지장애, 후기 경도 인지장애 환자를 분류 할 수 있었으며, 더 적은 차원에서도 분류가 가능했다. 이는 혈액 유전자 발현을 이용해 경도 인지장애 단계를 예측한 첫 번째 연구이며, 인지능력 저하에 따른 혈액 유전자 발현의 연관성을 확인하고 향후 조기 진단, 치료 표적 탐색에 기여한다.