• Korean System Dynamics Review
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• v.1 no.2
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• pp.91-111
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• 2000

Causal maps or cognitive maps have been widely used to get insights for complex systems or decision makers. When insights come from the system behavior rather than its structure, we need simulation of causal maps and cognitive maps. In this paper, a method for directly converting causal maps and cognitive maps into stock-flow diagrams that can be simulated in computers in proposed. This method is called as NUMBER. NUMBER is an abbreviation for 'Normal Unit Modeling By Elementary Relationship'. In this paper, NUMBER is applied to a cognitive map of policy maker to show its usefulness.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.229-237
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• 2021

Among the elderly and patients with mild brain diseases (such as dementia and stroke), when there is a certain degree of self-acting ability and cognitive ability, exercise and cognitive rehabilitation are often required. However, since most of the existing rehabilitation systems are separated or specialized in exercise or cognitive rehabilitation, there is a need for a form linking both. In this paper, we propose a game-type rehabilitation system that enables both exercise and cognitive rehabilitation using CAN communication protocol, one of ICT technologies. This system uses the CAN BUS structure to separate and combine each individual module constituting the rehabilitation system in various forms. A prototype of the proposed system was actually produced to show that various types of rehabilitation environments can be implemented according to the degree of cognitive ability and motor ability of the patient (or the elderly). In addition, through several experiments using this system, it is possible to implement exercise/cognitive parallel rehabilitation applicable to various environments.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.21-40
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• 2019

This paper presents a comprehensive survey of various artificial intelligence (AI) techniques implemented in cognitive radio engine to improve cognition capability in cognitive radio networks (CRNs). AI enables systems to solve problems by emulating human biological processes such as learning, reasoning, decision making, self-adaptation, self-organization, and self-stability. The use of AI techniques is studied in applications related to the major tasks of cognitive radio including spectrum sensing, spectrum sharing, spectrum mobility, and decision making regarding dynamic spectrum access, resource allocation, parameter adaptation, and optimization problem. The aim is to provide a single source as a survey paper to help researchers better understand the various implementations of AI approaches to different cognitive radio designs, as well as to refer interested readers to the recent AI research works done in CRNs.

• Journal of Communications and Networks
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• v.17 no.4
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• pp.394-405
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• 2015

This paper considers a wideband cognitive radio network which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and proposes a novel cognitive radio system that exhibits improved sensing throughput and can save power consumption of secondary user (SU) compared to the conventional cognitive radio system studied so far. More specifically, under the proposed cognitive radio system, we study the problem of designing the optimal sensing time and power allocation strategy, in order to maximize the ergodic throughput of the proposed cognitive radio system under two different schemes, namely the wideband sensing-based spectrum sharing scheme and the wideband opportunistic spectrum access scheme. In our analysis, besides the average interference power constraint at primary user, the average transmit power constraint of SU is also considered for the two schemes and then a subgradient algorithm is developed to obtain the optimal sensing time and the corresponding power allocation strategy. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

• Journal of Ocean Engineering and Technology
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• v.36 no.1
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• pp.61-81
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• 2022

The available underwater acoustic spectrum is limited. Therefore, it is imperative to avoid frequency interference from overlapping frequencies of underwater acoustic equipment (UAE) for the co-existence of the UAE. Cognitive technology that senses idle spectrum and actively avoids frequency interference is an efficient method to facilitate the collision-free operation of multiple UAE with overlapping frequencies. Cognitive technology is adopted to identify the frequency usage of UAE to apply cognitive technology. To this end, we investigated two principle underwater acoustic sources: UAE and marine animals. The UAE is classified into five types: underwater acoustic modem, acoustic positioning system, multi-beam echo-sounder, side-scan sonar, and sub-bottom profiler. We analyzed the parameters of the frequency band, directivity, range, and depth, which play a critical role in the design of underwater acoustic cognitive technology. Moreover, the frequency band of several marine species was also examined. The mid-frequency band from 10 - 40 kHz was found to be the busiest. Lastly, this study provides useful insights into the design of underwater acoustic cognitive technologies, where it is essential to avoid interference among the UAE in this mid-frequency band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.594-595
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• 2022

In the process leading to the continuous use of mobile payment system users, emotional and cognitive reactions are carried out. In this study, a questionnaire was conducted to determine the effect of external factors(social, system, service factors) of the mobile payment system on the continuous use of emotional responses(pleasure, emotional trust) and cognitive responses(cognitive trust). The structural model was tested using SPSS and PLS. As a result of the analysis, it was found that external factors affect emotional and cognitive responses, and cognitive responses affect continuous use.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.219-220
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• 2009

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1363-1370
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• 2023

Globally, the elderly population is increasing, making the primary concern of modern society the healthy aging and welfare and medical facilities for the elderly. However, many seniors experience cognitive decline due to aging, making cognitive activities crucial for them. In this context, a study has developed a cognitive activity support system for the elderly using the metaverse. To achieve this, the characteristics and needs of the elderly were analyzed to design an interface in the metaverse that they can easily use. Additionally, the type and difficulty of cognitive activities were adjusted to engage seniors in a captivating manner. Experimental results showed that the proposed system effectively enhances the cognitive abilities of the elderly. Thus, the personalized metaverse-based cognitive activity support system proposed in this study can be a valuable tool for improving the cognitive abilities of the elderly.

• Journal of Korea Game Society
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• v.11 no.6
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• pp.23-31
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• 2011

The cognitive abilities are functions in human brain. They are closely with the real life. The cognitive abilities are likely to be decreased when human gets older and older. Fortunately, due to the plasticity of human brain, it is possible to help recover and rehabilitate brain function. Those efforts are called brain training and cognitive ability training. The cognitive ability training needs continuous trials and efforts. But many users feel boring because of simple repetitive works. This paper proposes a cognitive training system implemented in a smart device. The proposed system is designed to make users to focus on the repetitive training by using game-based tasks on the smart device. It shows that the proposed system is effective to attention and flexible on cognitive training game.

• Journal of the Ergonomics Society of Korea
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• v.21 no.3
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• pp.25-34
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• 2002

The road sign in dynamic traffic system is an important element which affects on human cognitive performance on driving. Web-based vision system simulator was developed to examine the cognition time of the road sign in dynamic environment. This experiment the cognition time of the road sign in dynamic environment. This experiment was designed in with-subject design with two factors: vehicle speed and the amount of information of the traffic sign. It measured the cognition time of the road sign through two evaluation methods: the subjective test with vision system simulator and computational cognitive model. In these two evaluations of human cognitive performance under the dynamic traffic environment, it demonstrated that subject's cognition time was affected by both the amount of information of traffic sign and driving speed.