• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.976-984
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• 2012

Ad hoc networks can be used under difficult conditions, where it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio(CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. However, there is a problem that all CR user do not fairly use the primary user's idle bandwidth which has been sensed. In this paper, to solve this problem, we propose the spectrum sharing algorithm which uses the multiple orthogonal sequences based on the code division multiple access(CDMA). From the proposed algorithm, it is expected that system performance of CR based ad-hoc network is improved significantly and it can be applied to the implementation of CR based ad-hoc network system.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.60-65
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• 2011

Wireless devices can communicate between each other without existing infrastructure in mobile Ad-hod network. Ad hoc networks can be used under difficult conditions, where it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio (CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. In this paper, to improve detection performance of the energy detection which is widely used in CR based ad-hoc network, we propose multiple antenna system for CR based ad-hoc networks.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.1-9
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• 2021

Purpose : The purpose of this study was to investigate functional disability for the elderly in rural Korea and to identify influencing factors of functional disability. Methods : The data were collected for 76 community-dwelling elderly in rural area and above 65 years. We assessed cognitive function, functional disability, depression using LACLS, WHODAS 2.0, SGDS-K. Data were analyzed using descriptive statistics for general characteristics of subjects, Spearman's correlation among LACLS, SGDS-K, WHODAS 2.0, age, educational levels. And multiple regression was used to find influencing factors of functional disability. Results : As a result of this study, we identified that WHODAS 2.0 total score was 50.59, summary score was 9.94 and functional disability of the elderly in rural area is in the 70^th percentile. The highest level of disability occurred in areas related to 'life activities (household)', 'participation in society' and the lowest level of disability occured in areas of 'self-care', 'getting along with people'. Functional disability was significantly correlated with age (r=.398), cognitive function (r=-.547), depression (r=-.563) but not educational levels (r=-.215). Finally, we confirmed that depression (𝛽=.371), cognitive function (𝛽=-.263), widowed status (𝛽=.303), age (𝛽=.272), non-participation of community program (𝛽=.165) was significantly influencing factors of functional disability and the explanatory power of these factors was 52.80 %. Conclusion : This study revealed important factors of functional disability. Therefore, we need to consider these factors when we developed program related to health for the elderly (aged > 65 years) in rural Korea. Further, we need to standardize WHODAS 2.0 in order to enhance its applicability in clinical practices.

• Science of Emotion and Sensibility
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• v.11 no.4
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• pp.613-628
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• 2008

Mind reading is an essential part of normal social functioning and empathy plays a key role in social understanding. This study investigated how individual differences can have an effect on reading emotions in facial expressions, focusing on empathizing and systemizing. Two experiments were conducted. In study 1, participants performed emotion recognition test using facial expressions to investigate how emotion recognition can be different as empathy-systemizing type, facial areas, and emotion type. Study 2 examined how emotion recognition can be different as empathy-systemizing type, facial areas, and emotion type. An emotion discrimination test was used instead, with every other condition the same as in studies 1. Results from study 2 showed mostly same results as study 1: there were significant differences among facial areas and emotion type and also have an interaction effect between facial areas and emotion type. On the other hand, there was an interaction effect between empathy-systemizing type and emotion type in study 2. That is, how much people empathize and systemize can make difference in emotional discrimination. These results suggested that the empathy-systemizing type was more appropriate to explain emotion discrimination than emotion recognition.

• Korean Journal of Cognitive Science
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• v.18 no.2
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• pp.159-178
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• 2007

Lee & Kang (2002) showed that simultaneous phonological rehearsal significantly delayed the performance of multiplication but not subtraction, whereas holding an image in the memory delayed subtraction but not multiplication. This result indicated that arithmetic function is related to working memory in a subsystem-specific manner. The aim of the current study was to examine the neural correlates of previous finding using fMRI. For this goal, dual task conditions that required suppression or no suppression were manipulated. In general, several areas were more activated in the interference conditions than in the less interference conditions, although both conditions were dual condition. More important finding is that the specific areas activated in the phonological suppression rendition were right inferior frontal gyrus, left angular, and inferior parietal lobule, while the areas activated in the other condition were mainly in the right superior temporal gyrus and anterior cingulate gyrus. Furthermore, the areas activated in the phonological or visual less suppression condition were right medial frontal gyrus, left middle frontal gyrus, and bilateral medial frontal gyri, anterior cingulate cortices, and parahippocampal gyri, respectively. These results revealed that sharing the processing code invokes interference, and its neural basis.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.3
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• pp.121-130
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• 2020

Objectives: We investigated the differences in cognitive and emotional empathic ability between adolescents and adults, and the differences of the brain activation during cognitive and emotional empathy tasks. Methods: Adolescents (aged 13-15 years, n=14) and adults (aged 19-29 years, n=17) completed a range of empathic ability questionnaires and were scanned functional magnetic resonance imaging (fMRI) during both cognitive and emotional empathy task. Differences in empathic ability and brain activation between the groups were analyzed. Results: Both cognitive and emotional empathic ability were significantly lower in the adolescent compared to the adult group. Comparing the adolescent to the adult group showed that brain activation was significantly greater in the right transverse temporal gyrus (BA 41), right insula (BA 13), right superior parietal lobule (BA 7), right precentral gyrus (BA 4), and right thalamus whilst performing emotional empathy tasks. No brain regions showed significantly greater activation in the adolescent compared to the adult group while performing cognitive empathy task. In the adolescent group, scores of the Fantasy Subscale in the Interpersonal Reactivity Index, which reflects cognitive empathic ability, negatively correlated with activity of right superior parietal lobule during emotional empathic situations (r=-0.739, p=0.006). Conclusion: These results strongly suggest that adolescents possess lower cognitive and emotional empathic abilities than adults do and require compensatory hyperactivation of the brain regions associated with emotional empathy or embodiment in emotional empathic situation. Compensatory hyperactivation in the emotional empathy-related brain areas among adolescents are likely associated with their lower cognitive empathic ability.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.41-54
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• 2017

Physical activity has positive effects on cognitive functions by aging. However, it is rare to find research that have scientifically investigated the effects on the affective-cognitive function. Thus, this study aims to brain-scientifically research its effects of physical activity on the affective-cognitive function of adults in adolescence and senescence. As subjects of this study, a total of 60 males adults in D region were selected, and then equally divided into four groups of young exercise group(25~35y/o), young non-exercise group(26~35y/o), old exercise group(60~70y/o), and old non-exercise group(60~70y/o). As experiment tools, the EEG measuring equipment and International Affective Picture System(IAPS) were used. The experiment of this study used an affective-cognitive task where subjects pressed a button depending on emotional valence(positive, neutral, negative) shown in the pictures. During the task, EEG measured eight areas(Fp1, Fp2, Fz, C3, C4, Cz, T3, T4) out of brain areas in accordance with the international 10-20 electrode system, EEG was measured. For statistical analysis, a three-way ANOVA on $4(group){\times}3(stimulus){\times}8(area)$ was conducted. The results showed main effects of group in both reaction time and accuracy, and also in the latency of P3. And there was an interaction between group and stimulus the amplitude of P3. In conclusion, Physical activity has positive effects on the affective-cognitive function of people in adolescence and senescence.

• Korean Journal of Cognitive Science
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• v.19 no.1
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• pp.75-88
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• 2008

Visual scene contains lots of redundant information. To process this redundant information without increasing brain's volume, human visual system may summarize incoming information. If similar but different information are given to visual system, visual system extracts statistical properties of the information. One example of the statistical representation is representation of mean size. The mean representation is accurate and durable. The process of mean representation is suggested to be parallel. However, previous studies on the mean representation mostly used behavioral methods. The purpose of this study was to investigate which neural regions extracted the mean size of a set of circles using fMRI method. According to previous studies, BOLD signal of certain areas that were in charge of cousin stimuli decreased when the same stimuli presented repetitively. We used this paradigm and found that BOLD signal of right occipital area was decreased when same mean site was presented repeatedly. This results suggest that right occipital area is the locus of mean representation of visual stimuli.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.87-94
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• 2019

The purpose of this study is to predict the usefulness and predictable effects of the use of dementia prevention games and dementia management applications provided in smart-phones for the elderly. First, 6 dementia diagnostic tools used to verify the effectiveness of the dementia prevention program were selected and the cognitive domains tested by each diagnostic tool were extracted. Second, 29 smart-phone dementia prevention game applications and dementia management applications were selected and the expected effects after using these applications were analyzed in connection with the cognitive domain extracted from the dementia diagnosis tool. As a result, it was expected that it would be helpful to manage dementia prevention by improving cognitive function in certain areas when playing games or managing dementia continuously using smart-phone dementia prevention applications. Smart-phone dementia prevention applications will be useful in improving the cognitive ability of the elderly and preventing dementia by supplementing the limitations of the dementia prevention program that is operated offline through time-space ease of use, continuous usability and economic feasibility.

• Korean Journal of Cognitive Science
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• v.17 no.1
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• pp.53-74
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• 2006

Similarity has been considered as one of basic concepts of cognitive psychology which is useful for explaining cognitive structure and process. MDS models(Shepard, 1964; Nosofsky, 1991) and Contrast model(Tversky, 1977) were proposed as early models of similarity comparison process. But, there have been a lot of theoretical doubts about the conceptual validity of similarity as a result of empirical findings which could not be explained by early models. Goldstone(1994) assumed that similarity could be defined by alignment processes, and suggested structural alignment as a prospective alternative for solving conceptual controversies so far. In this study, basic assumption and algorithms of MDS models(Shepard, 1944; Nosofsky, 1991) and Contrast model(Tversky, 1977) were described shortly and some theoretical limitations such as arbitrariness of selective attention and correlated structures were discussed as well. The conceptual characteristics and algorithms of SIAM(Goldstone, 1994) were described and how it has been applied to cognitive psychology areas such as categorization, conceptual combination, and analogical reasoning were reviewed. Finally, some theoretical limitations related with data-driven processing and alternative processing and possible directions for structural alignment were discussed.