• 한국안전학회지
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• 제13권4호
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• pp.230-239
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• 1998

Though limited, Model Human Processor (MHP) has been used to explain the complex users' behaviors during human-computer interactions in a simplified manner. MHP consists of perceptual, cognitive and motor systems, each with processors and memories interacting with each other in serial or parallel mode. The important parameters of memory include the storage capacity, the decay time, and the code type of a memorized item. The important parameter of a processor is the cycle time. Using these features of the model, this study developed a computerized cognitive process simulator to predict the cognitive process time of a class match task process. An experimental validity test result showed that the mean prediction time for cognitive process of the class match task simulated 50 times by the simulator was consistent with the mean cognitive process time of the same task performed by 37 subjects. Animation of the data flow during the class match task simulation will help understand the invisible human cognitive process.

• 대한가정학회지
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• 제46권1호
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• pp.73-86
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• 2008

The purpose of this study was to investigate the personal traits of children's characteristics as well as those of mothers' on the children's maladjustment behaviors. The study subjects were 345 preschooler-mother pairs. Results revealed that boys exhibited more maladjustment behaviors than girls, as expected. The results of a three way ANOVA analyses indicated that the multiple interactive factors of the children's temperament, cognitive outcomes, and parenting attitudes significantly affected the children's maladjustment behaviors. This trend was only representative across the sample of boys. In this study, the interaction effects of negative parenting attitudes and the children's lower levels of cognitive development on the children's maladjustment capacity were accentuated among boys with temperamental vulnerability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4623-4643
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• 2015

This paper considers physical-layer security protocols in multicast cognitive radio (CR) networks. In particular, we propose dual-hop cooperative decode-and-forward (DF) and randomize-and-forward (RF) schemes using partial relay selection method to enhance secrecy performance for secondary networks. In the DF protocol, the secondary relay would use same codebook with the secondary source to forward the source's signals to the secondary destination. Hence, the secondary eavesdropper can employ either maximal-ratio combining (MRC) or selection combining (SC) to combine signals received from the source and the selected relay. In RF protocol, different codebooks are used by the source and the relay to forward the source message secretly. For each scheme, we derive exact and asymptotic closed-form expressions of secrecy outage probability (SOP), non-zero secrecy capacity probability (NzSCP) in both independent and identically distributed (i.i.d.) and independent but non-identically distributed (i.n.i.d.) networks. Moreover, we also give a unified formula in an integral form for average secrecy capacity (ASC). Finally, our derivations are then validated by Monte-Carlo simulations.

• Journal of Communications and Networks
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• 제16권2호
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• pp.130-139
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• 2014

Due to the unpredictable nature of channel availability, carrying delay-sensitive traffic in cognitive radio networks (CRNs) is very challenging. Spectrum leasing of radio resources has been proposed in the so called coordinated CRNs to improve the quality of service (QoS) experienced by secondary users (SUs). In this paper, the performance of coordinated CRNs under fixed-rate with hard-delay-constraints traffic is analyzed. For the adequate and fair performance comparison, call admission control strategies with fractional channel reservation to prioritize ongoing secondary calls over new ones are considered. Maximum Erlang capacity is obtained by optimizing the number of reserved channels. Numerical results reveal that system performance strongly depends on the value of the mean secondary service time relative to the mean primary service time. Additionally, numerical results show that, in CRNs without spectrum leasing, there exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, services with hard delay constraints cannot be even supported in CRNs. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by fixed-rate applications with hard delay constraints. Finally, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated.

• 대한치료과학회지
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• 제10권2호
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• pp.13-20
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• 2018

Objective: To investigate the effects of a brain fitness exercise on the cognitive function of patients with dementia. Method: Forty-six elderly adults diagnosed with dementia were randomly allocated to the study or control group (n=23 per group). The study and control groups performed a brain fitness and regular exercise, respectively, for 40 minutes a day, three times a week for four weeks. We examined cognitive capacity using MMSE-K, cognitive strength, judgment time, and mental workload scores before and after intervention. Results: The study group showed significant improvements in all variables. In addition, the control group showed a significant improvement in brain stress. We found that there was a significant improvement in the study group when compared with the control group in all variables. Conclusion: Based on these results, we suggest that brain fitness exercise would be effective in improving cognitive functions of dementia patients.

• 한국조경학회지
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• 제48권2호
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• pp.1-9
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• 2020

본 연구는 수목원·식물원의 이미지가 수용력 관련 정책 지지도에 미치는 영향을 밝히는 것을 목적으로 한다. 이를 위해 본 연구는 전국단위의 설문조사를 진행하였으며, 723부의 유효한 표본을 확보하였다. 탐색적 요인분석, 확인적 요인분석, 상관관계분석, 구조방정식모형을 이용한 분석결과, 수목원·식물원의 이미지는 정서적 요인, 인지적 요인, 형태적 요인으로 도출되었으며, 이 중 인지적 요인이 수용력 관련 정책 지지도에 유의한 영향을 미치는 것으로 나타났다. 이에 따라 수목원·식물원의 정책입안자들은 지속가능한 이용을 위해 꼭 필요한 수용력 조절정책을 도입하는 데 있어 방문객들의 지지를 이끌어내기 위해 인지적 이미지 요인을 계획 및 관리요인으로 활용할 수 있을 것이다.

• 한국통신학회논문지
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• 제39B권11호
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• pp.803-809
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• 2014

본 논문에서는 면허 사용자와 감청 사용자가 존재하는 인지무선 네트워크에서 릴레이 선택 기능을 이용한 물리 계층 보안 시스템을 제안하고 성능을 분석한다. 먼저 감청에 대한 보안성 확보를 위해 수신기 측에서의 채널 정보를 이용하는 기회적 최적 릴레이 선택 방법과 다중 안테나 다이버지시티를 이용하는 시스템을 제안한다. 이러한 시스템에서 인지무선 네트워크의 보안 outage 확률을 정의하고 수학적으로 정확한 확률 식을 유도한다. 아울러 송신전력에 제한이 없는 경우에 대한 점근적 outage 확률을 구한다. 수치 해석 결과를 제시함으로써 유도한 확률식의 정확성을 검증한다.

• 인지과학
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• 제15권3호
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• pp.1-14
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• 2004

본 연구에서는 순차적으로 자극이 제시되는 시각 구별 과제에서 개인차가 기술의 습득과 전이에 어떻게 영향을 미치는지 알아보았다. 여기서는 개인 차이를 세 가지 측면에서 측정하였는데 인지 양식의 차이, 작업 기억 용량의 수준, 그리고 의사 결정 방식의 차이를 가지고 개인 차이를 분류하였다. 시각 구별 과제에서는 크게 훈련 과정과 전이 과정으로 나누어 훈련 과정의 난이도가 전이 과정에서 어떠한 영향을 미치는지 알아보았는데, 특히 훈련 난이도는 인지 양식과 그리고 작업 기억 용량과의 상호 작용을 통하여 전이 과제에서의 정확도에 영향을 미친 것으로 나타났다. 본 연구에서 얻어진 결과는 시각 구별과 관련한 인터페이스를 디자인하는데 있어서 개인차를 고려하는 것이 필요함을 시사하였다.

• Journal of Communications and Networks
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• 제18권1호
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• pp.112-122
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• 2016

Cognitive radio (CR) is considered an attractive technology to deal with the spectrum scarcity problem. Multi-radio access technology (multi-RAT) can improve network capacity because data are transmitted by multiple RANs (radio access networks) concurrently. Thus, multi-RAT embedded in a cognitive radio network (CRN) is a promising paradigm for developing spectrum efficiency and network capacity in future wireless networks. In this study, we consider a new CRN model in which the primary user networks consist of heterogeneous primary users (PUs). Specifically, we focus on the energy-efficient resource allocation (EERA) problem for CR users with a special location coverage overlapping region in which heterogeneous PUs operate simultaneously via multi-RAT. We propose a two-tier crossover genetic algorithm-based search scheme to obtain an optimal solution in terms of the power and bandwidth. In addition, we introduce a radio environment map to manage the resource allocation and network synchronization. The simulation results show the proposed algorithm is stable and has faster convergence. Our proposal can significantly increase the energy efficiency.

• 지역사회간호학회지
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• 제30권2호
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• pp.243-255
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• 2019

Purpose: The purpose of this study is to examine effects of a multifactorial program for preventing the frailty of older adults and effects of a follow-up program applying a capacity building strategy. Methods: A quasi-experimental pretest-posttest design was used for the nonequivalent control group. The follow-up group (n=75) and non-follow-up group (n=68) received the same multifactorial program comprising muscle strength exercise, cognitive training, and psychosocial programs for 12 weeks. After completion of multifactorial program, the follow-up group took follow-up programs applying the capacity building strategy for following 12 weeks. The data of physical function, cognitive function, and psychological function, and self-rated health were collected from both groups three times: before intervention, after intervention, and 12 weeks after intervention. The data were analyzed using $x^2$ test and t-test. Results: In comparison with the non-follow-up group, the scores of Timed Up & Go Test, and physical activities energy expenditure were significantly improved in the follow-up group. Conclusion: These results indicate that a multifactorial program with follow-up adapting the strategies of capacity building for the older adults group is feasible to prevent the physical frailty in community.