• Safety and Health at Work
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• 제12권4호
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• pp.505-510
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• 2021

Background: Factors related to root causes can cause commonly occurring accidents such as falls, slips, and jammed injuries. An important means of reducing the frequency of occupational accidents in small- to medium-sized enterprises (SMSEs) of South Korea is to perform intensity analysis of the root cause factors for accident prevention in the cause and effect model like decision models, epidemiological models, system models, human factors models, LCU (life change unit) models, and the domino theory. Especially intensity analysis in a robot system and smart technology as Industry 4.0 is very important in order to minimize the occupational accidents and fatal accident because of the complexity of accident factors. Methods: We have developed the modern cause and effect model that includes factors of root cause through statistical testing to minimize commonly occurring accidents and fatal accidents in SMSEs of South Korea and systematically proposed educational policies for accident prevention. Results: As a result, the consciousness factors among factors of root cause such as unconsciousness, disregard, ignorance, recklessness, and misjudgment had strong relationships with occupational accidents in South Korean SMSEs. Conclusion: We conclude that the educational policies necessary for minimizing these consciousness factors include continuous training procedures followed by periodic hands-on experience, along with perceptual and cognitive education related to occupational health and safety.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.604-615
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• 2019

Single-user spectrum sensing is susceptible to multipath effects, shadow effects, hidden terminals and other unfavorable factors, leading to misjudgment of perceived results. In order to increase the detection accuracy and reduce spectrum sensing cost, we propose an adaptive cooperative sensing strategy based on an estimated signal-to-noise ratio (SNR). Which can adaptive select different sensing strategy during the local sensing phase. When the estimated SNR is higher than the selection threshold, adaptive double threshold energy detector (ED) is implemented, otherwise cyclostationary feature detector is performed. Due to the fact that only a better sensing strategy is implemented in a period, the detection accuracy is improved under the condition of low SNR with low complexity. The local sensing node transmits the perceived results through the control channel to the fusion center (FC), and uses voting rule to make the hard decision. Thus the transmission bandwidth is effectively saved. Simulation results show that the proposed scheme can effectively improve the system detection probability, shorten the average sensing time, and has better robustness without largely increasing the costs of sensing system.

• 스마트미디어저널
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• 제12권3호
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• pp.30-37
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• 2023

Alzheimer's disease (AD) symptoms are being treated by early diagnosis, where we can only slow the symptoms and research is still undergoing. In consideration, using T1-weighted images several classification models are proposed in Machine learning to identify AD. In this paper, we consider the improvised feature selection, to reduce the complexity by using wrapping techniques and Restricted Boltzmann Machine (RBM). This present work used the subcortical and cortical features of 278 subjects from the ADNI dataset to identify AD and sMRI. Multi-class classification is used for the experiment i.e., AD, EMCI, LMCI, HC. The proposed feature selection consists of Forward feature selection, Backward feature selection, and Combined PCA & RBM. Forward and backward feature selection methods use an iterative method starting being no features in the forward feature selection and backward feature selection with all features included in the technique. PCA is used to reduce the dimensions and RBM is used to select the best feature without interpreting the features. We have compared the three models with PCA to analysis. The following experiment shows that combined PCA &RBM, and backward feature selection give the best accuracy with respective classification model RF i.e., 88.65, 88.56% respectively.

• 한국과학교육학회지
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• 제35권3호
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• pp.487-498
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• 2015

이 연구는 TIMSS 2011을 기초한 학업성취도평가를 통하여 초등학생의 과학학습에 대한 내용영역과 인지영역의 관계를 분석하여, 학습자의 특성에 따른 과학교육에 시사점을 얻고자 하였다. 초등학생 4~6학년 317명을 대상으로 TIMSS 2011에서 공개된 총 41개의 선택형 문항으로 검사를 실시하여, 연구대상의 학년과 학업성취수준에 따라 평가 결과를 수집하였다. 이러한 자료를 바탕으로 연구대상의 특성에 따라 과학학습의 내용영역과 인지영역별 점수와 상관관계를 분석하고, 문항별 상관관계도를 통해 정적상관관계와 부적상관관계로 구분하여 그 결과를 비교하였다. 연구결과는 다음과 같다. 첫째, 연구대상의 학년에 따라 과학학습의 '물상과학'과 '추론하기'영역을 제외한 나머지 영역에서 유의미한 차이를 보였으며, 모든 내용영역과 인지영역별 상관관계도 연구대상의 학년에 따라 통계적으로 유의미한 상관관계를 나타내었다. 둘째, 연구대상의 학업성취수준에 따른 내용 및 인지영역의 차이는 모두 유의미한 차이를 보였으나, 연구대상의 학업성취수준과 과학학습의 내용 및 인지영역에 따른 상관관계의 양상은 서로 다르게 나타났다. 셋째, 문항별 정적상관관계도와 부적상관관계도에서 문항별 상관관계의 복잡성과 양상이 연구대상의 학업성취수준에 따라 뚜렷하게 구분되었다.

• 동의생리병리학회지
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• 제38권1호
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• pp.1-9
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• 2024

Cognitive reserve (CR) is a concept that can explain the discrepancies between the pathologic burden of the disease and clinical manifestations. It refers to the individual susceptibility to age-related brain changes and pathologies related to Alzheimer's disease, thus recognized as a factor affecting the trajectories of the disease. The purpose of this study was to explore the current states of clinical studies on neural substrates of CR in Alzheimer's disease using functional magnetic resonance imaging. We searched for clinical studies on CR using fMRI in the Pubmed, Cochrane library, RISS, KISS and ScienceON on August 14, 2023. Once the online search was finished, studies were selected manually by the inclusion criteria. Finally, we analyzed the characteristics of selected articles and reviewed the neural substrates of CR. Total thirty-four studies were included in this study. As surrogate markers of CR, not only education and occupational complexity, but also composite score and questionnaire-based method, which cover various areas of life, were mainly used. The most utilized methods in resting-state fMRI were independent component analysis, seed-based analysis, and graph theory analysis. Through the analysis, we demonstrated that neuroimaging techniques could capture the neural substrates associated with cognitive reserve. Moreover, functional connectivity of brain regions centered on prefrontal and parietal cortex and network areas such as default mode network showed a significant correlation with CR, which indicated a significant association with cognitive performance. CR may induce differential effects according to the disease status. We hope that this perspective on cognitive reserve would be helpful when conducting clinical researches on the mechanisms of traditional Korean medicine for Alzheimer's disease in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.799-818
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• 2014

Spectrum sensing is a key technical challenge for cognitive radio (CR). It is well known that multi-cycle cyclostationarity (MC) detector is a powerful method for spectrum sensing. However, conventional MC detector is difficult to implement due to its high computational complexity. This paper pays attention to the fact that the computation complexity can be reduced by simplifying the test statistic of conventional MC detector. Based on this simplification process, an improved MC detector is proposed. Compared with the conventional one, the proposed detector has the low-computational complexity and sufficient-accuracy on sensing performance. Subsequently, the sensing performances are further investigated for the cases of Rayleigh, Nakagami-m, Rician, composite Rayleigh fading-lognormal shadowing and composite Nakagami fading-lognormal shadowing channels, respectively. Furthermore, the square-law combining (SLC) is introduced to improve the detection capability over fading-shadowing channels. The corresponding closed-form expressions of average detection probability are derived for each case by the moment generation function (MGF) approach. Finally, illustrative and analytical results show that the efficiency and reliability of proposed detector and the improvement on sensing performance by SLC over composite fading-shadowing channels.

• 인지과학
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• 제27권2호
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• pp.247-273
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• 2016

기존 거짓말 연구들은 대면 상황에서 말이나 진술서 등 거짓말을 하는 사람들이 불안할 수 있는 상황에서 주로 행해졌다. 본 연구는 거짓이라는 사실이 밝혀질 우려가 없거나 밝혀지더라도 그로 인한 손해가 거의 발생하지 않는 비압박 상황에서 자기 태도에 반하는 거짓글을 쓸 경우에 나타나는 언어적 특징을 K-LIWC를 통해 분석하였으며 기존의 거짓말 연구결과와 비교를 하였다. 두 번의 글쓰기 과제에서 태도를 기만하는 거짓 글은 진실한 글에 비해 1인칭 단어의 사용 빈도가 떨어지는 것으로 나타났다. 인지적 복잡성을 나타내는 변인들은 첫 번째 글쓰기 과제에서는 더 낮게, 두 번째 글쓰기 과제에서 더 높게 결과가 나타났다. 특히, 거짓말에는 부적 정서 단어들이 많이 사용된다는 기존 연구 결과와는 달리, 비압박 상황에서는 긍정 정서의 단어들이 더 많이 사용되는 것으로 나타났다. 본 연구 결과는 상황적 요인의 차이로 심리적 상태가 달라지면 사용하는 언어 또한 달라질 수 있다는 것을 시사한다.

• 한국통신학회논문지
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• 제36권6A호
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• pp.592-600
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• 2011

본 논문에서는 상황인식(CR: Cognitive Radio) 시스템에서 CR 시스템이 우선사용자와 spectrum leasing 관계에 있을 때 간섭을 많이 주는 사용자를 선택하고 이들에게 선택적으로 부분공간 간섭정렬방식을 적용해 우선사용자와 CR 사용자에게 모두 데이터 전송을 가능케 하는 방식을 제안하였다. 각 기지국들은 사용자의 간섭 신호량을 가지고 자신의 기지국에서 요구하는 복호 가능한 SINR(signal-to-interference ratio)를 넘지 않도록 주변 셀의 간섭신호가 큰 사용자들을 순환적으로 선택하고 이들에게 선택적으로 부분공간 간섭정렬방식을 적용하는 방법이다. 제안된 방법으로 모든 사용자들은 다른 간섭에 대한 제약 없이 통신이 가능하게 된다. 전산모의실험으로 제안한 방법은 선택적 간섭정렬을 적용 안 하는 방법보다 합 용량에서 약 350% ~400% 증가함을 보였다.

• Annals of Clinical Neurophysiology
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• 제8권2호
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• pp.135-145
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• 2006

Background: Parkinson's disease is movement disorder due to dopaminergic deficiency. It has been noted that cognitive dysfunction also presented on Parkinson's disease patients. But, it is not clear whether such a cognitive dysfunction was a dopaminergic dysfunction or cholinergic dysfunction. Using linear and non-linear analyses, we analysed the effect of cognitive and motor symptom on EEG change. Methods: EEGs were recorded from patients with Parkinson's disease and essential tremor, and normal controls during rest. We calculated the power spectrum, correlation dimension and Lyapunov exponent by using 'Complexity'program. The power spectrum, correlation dimension, and Lyapunov exponent were compared between Parkinson's disease patients and essential tremor patients. Results: Theta power was increased in Parkinson's disease patient group. Correlation dimension was increased in Parkinson's disease patients. Positive correlation was noted between MMSE and correlation dimension, and negative correlation was noted between MMSE and Lyapunov exponent. Lyapunov exponent was decreased in Parkinson's disease patient. Conclusions: We conclude that the state of Parkinson's disease patient is characterized by increased correlation dimension and decreased Lyapunov exponent.

• 한국환경교육학회지:환경교육
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• 제15권1호
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• pp.68-82
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• 2002

My responses to Kim Kyung-Ok's Critique on my critique on the Hungerford approach can be summarized as follows; First, it was argued that possible confusions and misunderstandings around the concept of behavior in REB were mainly caused by Hungerford himself who has used the word in several different ways, from a bunch of overt actions to almost all kinds of responses including cognitive skills, without any clear operational definition of it for more than 20 years. It seems to be needed for future users of the word, 'Behavior' to Prevent unnecessary confusions by providing their operational definition of it. Second, REB is too ambiguous to be a legitimate goal of environmental education and too outcome-oriented to be a meaningful measure for environmental education research. Anyone who accept REB as a goal of EE or a measure for research should clearly suggest procedures and criteria for judging the environmental responsibility of actions under consideration. Third, the Hungerford approach has begun by realizing the limit of a linear traditional behavior change system and has been evolving toward a complex model with dynamic interactions among/between cognitive variables and affective variables. However, it still has one-way structural orientation toward 'Behavior' with no feedbacks. Addition of some feedback processes would make the model more flexible and realistic. Finally, both the Hines model and the Hungeford model were established based on a series of behavioristic studies including three doctoral dissertations equiped with a list of actions which were prejudged to be environmentally responsible by the researchers, not by the learners. What they were primarily interested in was not how mind functions during the learning processes but how learners' behavior can be effectively changed. Considering uncertainty and complexity associated with environmental problems, a great deal of efforts ought to be made toward more context-based and less normative studies applying cognitive psychology and quantitative approaches.