• 대한물리치료과학회지
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• 제19권2호
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• pp.55-61
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• 2012

Background : The purpose of this study is to provide the basic data according to cognitive function, that will help activities of daily living of the elderly through the comparative study of activities daily living and functional training. Methods : The subjects of this study 122 patients 65 years old or more ADL and cognitive function assessment was evaluated. They were registered in the Elderly in nursing homes and welfare centers, located in Gyeonggi. All study participants had a sufficient explanation for the purposes of research and evaluation methods and procedures for the elderly. The survey period 17 October to 11 November 2011 was conducted through face-to-face survey was conducted. Results : Cognitive function according to the K-MMSE score of 24 points or more, 23 to 18 points, 17 points or less were classified. Ability to perform activities of daily living (personal hygiene, bathing, toilet use, stair climbing, dressing, stool control, urinary control, gait, chair/bed, etc.) according to the degree of cognitive function by evaluating the ability to perform daily living compared results in all variables were statistically significant (p<.5). Conclusion : As a result, the higher cognitive functions can be seen that the higher the ability to perform activities of daily living.

• 재활간호학회지
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• 제16권2호
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• pp.90-99
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• 2013

Purpose: This study aimed to examine influence of cognitive function, disease severity and disability on ability to perform activity of daily living (ADL) after ischemic stroke. Methods: A total of 88 patients with ischemic stroke were recruited from January 1, 2008 to December 31, 2012 and assessed with the standardized cognitive test battery and self-reports about disease severity, disability, and ADL. To analyze the data, ANOVA, Pearson correlation coefficients and multiple regression were conducted using SPSS/WIN program. Results: Significant correlations were found between ADL and visuospatial function, visual memory, executive function, and disability (r=.29~.38). Executive function and disability explained 17.3% of total variability in ADL performance after ischemic stroke. Conclusion: Executive function may be a promising target for cognitive rehabilitation after ischemic stroke. Thus, effective therapeutic interventions such as cognitive training for stroke patients should be considered to improve their ability to perform ADL.

• 한국정보시스템학회지:정보시스템연구
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• 제29권2호
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• pp.265-286
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• 2020

Purpose Among various psychosocial factors, negative social comparison, attention blocking to stimuli, and cognitive interference via information overload are considered most critical in hindering the effective performance improvement of computer-based idea generation. Given that the effect of negative social comparison along with a plausible solution based on the notion of performance feedback and goal setting has been successfully addressed, this study focused on the remaining issues of "attention blocking to stimuli and cognitive interference via information overload" and attempted to find a way to alleviate the effect of such process losses on performance. Design/methodology/approach A 2 × 4 between-subjects design was used, crossing cognitive ability (high and low) and personality (extroversion and introversion). Five subjects per each treatment were randomly selected to make the sample size equal. The group simulator was used to measure individual-level performance. The dependent variables were the quantity of and quality score of ideas. The manner by which these performance measures were operationalized was consistent with prior studies. An additional analysis using the number of diverse ideas was also conducted. Findings Three arguments were made in this study: (1) high cognitive individuals would perform better than low cognitive individuals, (2) extraverted individuals would perform better than introverted individuals, and (3) cognitive ability and personality would interact such that individuals in Q1 would have the highest performance. Cognitive ability had an effect on quality not quantity. Personality had an effect on both quantity and quality. An interaction between cognitive ability and personality was not found due to small sample size despite the use of the group simulator.

• Journal of information and communication convergence engineering
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• 제9권2호
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• pp.166-171
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• 2011

This paper investigates the design issues of spectrum sensing in the cognitive radio (CR) networks of opportunistic unlicensed spectrum access. The cognitive radios can perform a communication using the incumbent user spectrum band without the interference caused by the cognitive radio users. In this case, the cognitive radios must know the real-time radio environments of the incumbent user spectrum band using the spectrum sensing, beacon signal, and geo-location database access. Then in this paper, we are going to provide spectrum sensing issues which include the sensing techniques, the regulatory requirements, the analysis of DTV detection threshold, and main considerations associated with the spectrum sensing design in cognitive radio systems. Also, this paper introduces design trade-offs in order to optimize the sensing parameters such as sensing time and sensing complexity.

• 한국통신학회논문지
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• 제37권7A호
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• pp.560-568
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• 2012

인지 라디오가 무선통신을 효과적으로 수행하기 위해서, 가장 좋은 주파수 대역을 얻기 위해 수행해야 할 중요한 기능은 스펙트럼을 검출하고 결정하는 것이다. 이러한 것들은 서로 다른 요구조건을 갖는 사용자들이나 서로 다른 특성들을 갖는 채널들이 존재하는 이종 네트워크에서 더욱 나빠진다. 본 연구의 주요한 목적은 이종 인지 무선 네트워크에서 새로운 스펙트럼 결정 알고리즘을 설계하고 분석한다. 이것을 위해, 우선 인지 사용자들을 그들이 요구하는 서비스 품질(QoS)에 따라 서로 다른 트래픽 클래스들로 분류한다. 중앙 집중형 제어 형태로 동작하는 그룹단위의 협력 스펙트럼 검출은 하나의 트래픽 클래스내의 사용자들에 의해서 검출과정이 수행되며, 이 센싱 결과들은 나머지 트래픽 사용자들과 공유하는 형태이다. 다음은 사용자 요구조건들과 검출된 스펙트럼 채널 특성들에 따라 최적의 사용 가능한 대역을 선택하기 위해 계층 분석법(AHP)을 사용한다. 또한 스펙트럼 결정 알고리즘으로 효용함수를 사용한다. 시뮬레이션 분석 결과로서, 제안된 시스템은 가장 좋은 이용 가능한 스펙트럼 채널들을 효율적으로 선택할 수 있음을 보여주며, 시스템 구성의 복잡성을 감소시켜 줄 수 있음을 보여준다.

• 한국통신학회논문지
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• 제34권11A호
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• pp.822-830
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• 2009

The spectrum efficiency of mobile communication networks can be improved dramatically adopting multiple antennas technologies. In order to guarantee the licensed rights of primary user (PU), the cognitive radio system should perform in a relatively low interference manner when it gets access to the spectrum of licensed networks. In this paper, we explore a uniformly distributed circular antenna array to implement beamforming algorithm that is accomplished by optimization method at the base station of cognitive radio networks, and therefore we can suppress the interference to PU by steering quite low transmission power toward PU and constructing a narrow beam toward cognitive user (CU). By reducing the constraint number of the optimization problem, we also propose a null steering algorithm that steers rather low radiation power toward PU, while the other areas in the same cell are covered by radiation power except the local area around PU. It is pursued to reduce the computation load and enlarge the capacity of cognitive radio networks extremely. The simulation results demonstrate that the proposed algorithms process superior performance.

• 국제물리치료학회지
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• 제3권2호
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• pp.453-457
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• 2012

The Goal of this study was to assess the effect of aerobic exercise on cognitive function of elderly people. The participants' cognitive functions were measured before exercise. Exercise was practiced three times a week for nine weeks. The aerobic exercises consisted of warm-up exercises for five minutes followed by cycling for 30 minutes. The exercise intensity was set to 65%~75% of the intensity for the maximum heart rate(220-age). The control group did not perform any exercises. The subjects' cognitive functions were measured nine weeks later. In the aerobic exercise group, between before and after the exercises, significant increases appeared in total K-MMSE scores and scores of some sub items comprising memory registration, concentration and calculation abilities but not in other items. In the control group, no significant differences appeared in any items between before and after the experiment. In a comparison between the aerobic exercise group and the control group, significant differences appeared in total K-MMSE scores and scores of two sub items comprising concentration and calculation abilities but not in other items(p<.05). Aerobic exercises were effective in the improvement of cognitive functions and among sub items of cognitive functions, concentration and calculating abilities were improved. Aerobic exercises performed by elderly persons are considered to be effective in improving cognitive functions.

• 대한인간공학회지
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• 제34권4호
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• pp.335-351
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• 2015

Objective: The aim of this study was to perform a usability test for CPAD (Cognitive Perceptual Assessment for Driving) and improve it based on the test results. Background: The cognitive perceptual assessment for driving is a computer-based assessment tool to assess the driving capacity of people with brain-damages. It may be a good tool for evaluating the brain-damaged drivers' safe driving capabilities and screening cognitive and perceptual deficits related to driving. We performed a usability test to improve the CPAD based on the result. Method: Both the software consisting of 8 sub-tests (depth perception, sustained attention, divided attention, stroop test, field dependency, digit span, trail making A, trail making B) and the hardware including the input and output devices ( joystick, mouse, keyboard, touch screen) were evaluated through user interviews. Also we identified the problems and issues in using them by observing the participants performing the CPAD tasks. Results: Based on the results, the task instructions were visually and auditorily improved and more practice examples were added to help the users understand the instructions better and increase the input accuracy, a response time window was added and the joystick and touch screen were simplified, which made it easier for the user to perform the CAPD tasks. Conclusion: User discomforts were minimized by improving the task environment, unless it had affected the evaluation criteria. Application: We plan to distribute the improved version of the CPAD to the regional rehabilitation hospitals, and the driving support centers for people with disabilities throughout the country, so it could be used as an evaluation tool for disabled drivers' cognitive and perceptual functions.

• 한국정밀공학회지
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• 제22권4호
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• pp.173-180
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• 2005

In this study, changes in verbal cognitive performance, blood oxygen saturation and heart rate due to 30％ concentration oxygen supply were observed. Five male (24.6±0.9) and five female (22.2±1.9) college students were asked to perform 28 verbal cognitive tasks of the same difficulty during two types of oxygen (concentration 21％, 30％) administration. The experimental sequence consisted of Rest1 (1 min.), Control (1 min.), Task (4 min.), and Rest2 (4 min.) and the physiological signals such as blood oxygen saturation and heart rate were measured throughout the stages. The experimental result showed that the performance increased significantly at 30％'s concentration of oxygen rather than 21％'s, which shows oxygen supply has positive influence on verbal cognitive performance. When 30％ concentration oxygen is supplied, the oxygen saturation in the blood significantly increased comparing to 21％. The heart rate showed no significant difference. Significant correlations were found between changes in oxygen saturation and cognitive performance. It is suggested that 30％ oxygen can stimulate brain activation by increasing actual blood oxygen concentration in the process of cognitive performance.

• 생물정신의학
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• 제4권1호
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• pp.36-42
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• 1997

Higher cognitive functions refer to the highest level of human intellectual functioning, including concept formation, reasoning, and executive functions. The executive functions can be conceptualized as having four components : volition, planning, purposive action, and effective performance. Because higher cognitive functions represent the most advanced stages of intellectual development, they are often highly susceptible to the effects of brain injuries and mental disorders. The ability to perform effectively within the environment is determined in large part by an individual's adequacy in performing such higher-order functions. Especially executive functions are necessary for appropriate, socially responsible, and effectively self-serving adult conduct. Threfore, an assessment of the psychiatric patient's performance in these areas will provide useful diagnostic information, as well as information concerning social and vocational prognosis.