• Journal of Communications and Networks
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• 제13권1호
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• pp.50-55
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• 2011

Spectrum leasing for cognitive radio (CR) networks is an effective way to improve the spectrum utilization. This paper presents an opportunistic relaying based spectrum leasing for CR networks where the primary users lease their frequency band to the cognitive users. The cognitive users act as relays for the primary users to improve the channel capacity, and this improved capacity is used for the transmission of secondary users' data. We show that the cognitive users can use a significant portion of the communication resource of primary networks while maintaining a fixed target data rate for the primary users. Moreover, the primary network is also benefited by the cooperating cognitive users in terms of outage probability. Information theoretic analysis and simulation results are presented to evaluate the performances of both primary and cognitive networks.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.17-24
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• 2023

Given the surge in the elderly population, and increasing in dementia cases, there is a growing interest in digital therapies that facilitate steady remote treatment. However, in the cognitive assessment of digital therapies through clinical trials, the absence of log data as an essential evaluation factor is a significant issue. To address this, we propose a solution of utilizing weighted derived variables based on high-importance variables' accuracy in log data utilization as an indirect cognitive assessment factor for digital therapies. We have validated the effectiveness of this approach using machine learning techniques such as XGBoost, LGBM, and CatBoost. Thus, we suggest the use of log data as a rapid and indirect cognitive evaluation factor for digital therapy users.

• ETRI Journal
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• 제42권1호
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• pp.36-45
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• 2020

A priority-based data communication approach, developed by employing cognitive radio capacity for sensor nodes in a wireless terrestrial sensor network (TSN), has been proposed. Data sensed by a sensor node-an unlicensed user-were prioritized, taking sensed data importance into account. For data of equal priority, a first come first serve algorithm was used. Non-preemptive priority scheduling was adopted, in order not to interrupt any ongoing transmissions. Licensed users used a nonpersistent, slotted, carrier sense multiple access (CSMA) technique, while unlicensed sensor nodes used a nonpersistent CSMA technique for lossless data transmission, in an energy-restricted, TSN environment. Depending on the analytical model, the proposed wireless TSN environment was simulated using Riverbed software, and to analyze sensor network performance, delay, energy, and throughput parameters were examined. Evaluating the proposed approach showed that the average delay for sensed, high priority data was significantly reduced, indicating that maximum throughput had been achieved using wireless sensor nodes with cognitive radio capacity.

• 한국학교ㆍ지역보건교육학회지
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• 제24권4호
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• pp.27-37
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• 2023

Objectives: The purpose of this study was to investigate the effect of handgrip strength level on cognitive impairment in hypertensive patients. Methods: This study used the first to eighth year data of the Korean Longitudinal Study of Aging (KLoSA). Of the 10,254 respondents who participated in the basic survey, respondents were included that they were diagnosed with high blood pressure and had no cognitive impairment. The handgrip strength was based on the highest value of handgrip strength for both hands. Cognitive function using MMSE results and 23 points or less were defined as cognitive impairment. Cox models were conducted to estimate the hazard ratios (HRs) of cognitive impairment in relation to handgrip strength adjusting for covariates. Results: In the case of hypertension patients, the probability of cognitive decline decreased by 3.0% every time the maximum handgrip strength increased by 1 unit. In the analysis by age, under the age of 64 had a 1.8% decrease in the probability of cognitive decline whenever the maximum handgrip strength increased by 1 unit, and a 3.6% decrease in those over the age of 65. In the gender analysis, male had a 3.2% decrease in the probability of cognitive decline for every 1 unit increase in the maximum handgrip strength, and female had a 2.6% decrease. Conclusions: The results of this study are expected to be used as basic data for the development of interventions to prevent cognitive decline in hypertensive patients by identifying the effect of handgrip strength level on cognitive decline. It is also expected to be used as basic data for health education on the necessity of increasing muscle strength for hypertension patients in the community.

• 보건의료산업학회지
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• 제10권3호
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• pp.147-158
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• 2016

Objectives : The aim of this study was to investigate predictors of cognitive function decline among community dwelling elderly. Methods : Data were analyzed from the Survey of Living Condition of Elderly panel study. Cognitive function was measured with the MMSE-KC at baseline and year 3. The study subjects were 5,464 community dwelling people aged 65 years or older who had no disability at baseline. Logistic regression analysis was used to predict cognitive function decline. Results : From 2008-2011, 4,417(80.8%) elderly people had no cognitive decline, and 1,074(19.2%) showed cognitive function decline measured by the MMSE-KC. After adjusting for demographics and baseline MMSE-KC score, the best predictors for cognitive function decline at 36 months were diabetes mellitus, smoking, low intensity physical activity, relationship with relatives and friends. Conclusions : Health promotion programs that are focused on the elderly are essential in preventing cognitive function decline. Promoting regular physical activity, and social relationships should be included in health promotion for elderly. When treating patients with diabetes, preventing cognitive impairment should be considered through education and counseling.

• 중환자간호학회지
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• 제13권3호
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• pp.75-85
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• 2020

Purpose : This study aimed to identify the prevalence and risk factors of cognitive impairment in survivors discharged from the intensive care unit (ICU). Methods : This secondary analysis study utilized data from a multicenter prospective cohort of post-ICU patients. We analyzed the data of 175 patients enrolled in the primary cohort who completed the cognitive function evaluation three months after ICU discharge. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale. The cut-off points for cognitive impairment were < 23 for face-to-face evaluation and < 18 for telephone evaluation. Results : The prevalence of cognitive impairment three months after ICU discharge was 32.6%. Significant risk factors for cognitive impairment were age ≥ 60 years (OR=10.52, 95% CI=3.65~30.33, p<.001), education < high school graduation (OR=2.53, 95% CI=1.07~6.01, p=.035), unplanned ICU admission (OR=4.01, 95% CI=1.45-11.14, p=.008), and delirium in the ICU (OR=4.33, 95% CI=1.08-17.23, p=.038). Conclusion : ICU nurses should use preemptive strategies to reduce post-ICU cognitive impairment of patients with risk factors. It is necessary to frequently assess and detect early delirium in critically ill patients, while attempting various non-pharmacological interventions.

• 대한통합의학회지
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• 제8권4호
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• pp.59-66
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• 2020

Purpose : This study aimed to present normative data for older Korean adults completing the Yonsei dual task cognitive screening test (Y-DuCog) and identify changes in cognitive function on the Montreal Cognitive Assessment - Korean (MoCA-K) with age. Methods : From May 2019 to August 2019, 195 healthy adults aged ≥60 years participated in this study. All participants completed the Y-DuCog to assess their dual-task performance and the MoCA-K to assess their cognitive function. Participants were divided into three groups based on their age: 60~69 years, 70~79 years, and ≥80 years. Results : The results of the Y-DuCog showed that dual-task performance time, effect, and correct response rate decreased significantly with age (p<.001). Scores from the three groups showed differences on all items (p<.001). Cognitive function on the MoCA-K also decreased significantly with age (mean score ± standard deviation [SD]; 27.33 ± 2.61 in subjects aged 60~69 years; 24.82 ± 3.20 in subjects aged 70~79 years; and 22.10 ± 4.91 in subjects aged ≥80 years; p<.001). Conclusions : Occupational therapists should be aware of the decline in cognitive function and dual-task performance time, effect, and correct response rate in older adults and consider interventions to treat this decline. Further studies are needed with larger groups of participants to examine factors, such as sex and education, that may impact dual-task performance and cognitive function.

• 컴퓨터교육학회논문지
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• 제20권2호
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• pp.57-65
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• 2017

세계적으로 시니어인구는 지속적으로 증가하고 있는 추세이다. 특히 디지털 둔감 계층이었던 과거의 시니어와는 다르게 스마트 기기 및 인터넷을 지속적으로 사용하고자 하는 스마트 시니어 계층이 급부상하고 있다. 기존에 시니어에 대한 정의는 단순히 고연령 집단으로 정의하는게 대부분이었고, 시니어에 대한 특성을 파악하는 연구는 심리학연구에서 많이 이루어져 왔지만, 데이터 기반의 시니어 인지반응을 활용한 연구는 초기수준에 불과하다. 또한 스마트 시니어의 인지적 특성에 따른 콘텐츠를 제공해주기 위해서는 스마트 시니어의 인지적 특성을 잘 분류할 필요성이 있다. 따라서 본 논문은 스마트 시니어에 대한 인지반응 유형 분류를 통하여 시니어를 위한 문화향유에 도움을 줄 수 있도록 하는 데이터기반의 시니어 인지반응 모델링 방법을 제언한다.

• 대한통합의학회지
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• 제8권4호
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• pp.277-289
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• 2020

Purpose : This study aims to confirm the clinical usefulness of computerized cognitive therapy program for patients with brain diseases in Korea and to present basic data that can confirm the effectiveness of computerized cognitive therapy program to experts related to rehabilitation in the future. Methods : A systematic review and meta-analysis research method was used to confirm the clinical effectiveness of computerized cognitive therapy applied to patients with brain diseases in Korea. Based on the national institute of health and medical colleges association (NECA) systematic literature manual and preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines for conducting research through systematic review and meta-analysis methods. Systematic review was PICOST-SD was used to research and select papers. For meta-analysis, the data was input and analyzed separately by literature result using the revman manager 5.3 program and the results were presented visually through tables and forest, funnel plot figure. Results : As a result of comprehensive analysis of the contents of the finally selected literature, it as found that studies on stroke and dementia were mainly conducted. In addition, through the evaluation of the quality of the literature, most of the existing computerized cognitive therapy studies were identified as high-quality studies, but the results were insufficient for randomization and blinding. And through meta-analysis, the clinical effectiveness of computerized cognitive therapy on cognitive function, activities of daily living, and visual perception function of patients with brain disease was found. Conclusion : The research literature that applied computerized cognitive therapy to brain disease subjects was comprehensively analyzed and identified. It is thought that this could be used as basic data on the characteristics of cognitive therapy that should be applied to patients with brain diseases in the future and the usefulness of computerized cognitive therapy program in actual clinical practice.

• 지역사회간호학회지
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• 제28권3호
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• pp.251-259
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• 2017

Purpose: This study aims to examine the influence of vitamin D and calcium on depression and cognitive function of the elderly living alone in a city. Methods: The participants were registered in eight senior centers in S city and they had lived alone. Data were collected between November 28, 2014 and March 7, 2015. A total of 155 people participated in data collection to measure the serum vitamin D, the serum calcium, depression, and cognitive function. The data were analyzed with t-test, ANOVA, Pearson's correlation and multiple regression analysis. Results: There were significant differences in depression according to gender and perceptions of health status. Depression correlated significantly with the serum calcium and perceptions of health status, and a stepwise regression analysis showed that the perceptions of health status were significant. There were significant differences in cognitive function according to education level and age. Cognitive function correlated significantly with the serum vitamin D and a stepwise regression analysis showed that education level and age were significant. Conclusion: Consequently, elderly people with poor perceptions of their health status need a depressive intervention program and those with a higher age and lower level of education need a cognitive function intervention program.