• 한국전문물리치료학회지
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• 제17권3호
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• pp.20-30
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• 2010

This study examined whether any changes by mental task types on postural control in chronic stroke persons. Sixteen chronic stroke persons (mean age=53.75 yr) and sixteen age-and gender-matched healthy controls (mean age=54.44 yr) took part in this study. Participants randomly performed three different tasks on the stable and unstable surfaces. The no mental task was to stand while holding a 100 g weight in each hand, the arithmetic task (mental task) was to perform a silent 1-backwards counting while standing and holding a 100 g weight in each hand, and the simple task (mental task) was to stand and hold with both hands a tray (200 g) on which a glass filled with water has been placed. Sway path and sway velocity of the center of pressure (COP) were measured to assess standing postural control by task performance using the force platform. According to the results, in stroke group, total sway path and total sway velocity of COP was significantly decreased during arithmetic and simple task compared to no mental task on the stable surface (p<.05), and sway path (anteroposterior AP, mediolateral ML) of COP, total and sway velocity (AP, ML, total) of COP was significantly decreased during arithmetic and simple task compared to no mental task on the unstable surface (p<.05). Especially, sway path (AP, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased under the simple task when compared to the arithmetic task on the unstable surface (p<.05). In healthy control group, sway path (AP, ML, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased during arithmetic and simple task compared to no mental task on the stable and unstable surface (p<.05), and sway path (AP, total) of COP and sway velocity (AP, ML, total) of COP was significantly decreased under the simple task when compared to the arithmetic task on the unstable surface (p<.05). In conclusion, the findings of this study showed that arithmetic and simple task improved standing postural control for chronic stroke patients and the type of arithmetic and simple tasks were critical factor that reduced standing postural sway in dual-task conditions. Future research should determine whether dual-task conditions, including simple task, would be effective as a training program for standing postural control of stroke patients.

• 대한인간공학회지
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• 제29권4호
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• pp.605-610
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• 2010

In order to design a touch interface for the elderly, human performance of input tasks on the touch screen was investigated by the laboratory experiment. Input times and input errors were measured in the experimental conditions that were changed according to age, key size, interkey space and input tool(finger or stylus pen). In the most of all experimental conditions, the task performance of the elderly was lower than that of the young. However, there were significantly different performance patterns between both groups. As the difficulty of task was getting higher, the task performance of the elderly was sharply decreased; pressing small key button by finger sharply increased input time and error rate, compared to that of the young. Therefore, the square key size suitable to the elderly may be over $8.0{\times}8.0mm$. While the interkey space did not influence to the input task performance of the young, the task performance of the elderly was influenced. The elderly showed big difference of task performance according to input tool. However, the young were less influenced by input tool.

• 아동학회지
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• 제34권6호
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• pp.1-11
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• 2013

The purpose of this study was to investigate the process of counterfactual reasoning which children undergo, based on mental model theory and dual process theory. The subjects were 120 four-year-olds and 120 five-year-olds from Ulsan. Counterfactual reasoning task conditions were created, including task type and content, which were type 1-specific, type 1-general, type 2-specific, type 2-general. There were two stories used for each task condition. Children's counterfactual reasoning score range was 0 to 8. Data were analyzed using SPSS by mean, standard deviation, one sample t-test, repeated measures of Anova. The results of this study were as follows. First, children's counterfactual reasoning was above chance level regardless of the task condition. Second, children's counterfactual reasoning was lowest when type 1-specific or type 2-specific tasks were given, slightly higher when type1-general tasks were given, and the highest when type 2-general tasks were given. There was no significant difference between 4-year-old and 5-year-old children's counterfactual reasoning.

• 한국전문물리치료학회지
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• 제12권3호
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• pp.67-73
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• 2005

Prospective memory (PM) is related to remember to carry out a previously intented behaviour. The purpose of this study was to develop a paradigm for measuring PM function to diagnosis in mild cognitive impairment 1 or brain injury in patients 2. among brain injured patients Thirty-eight normal healthy subjects participated in current study. The paradigm was composed of four conditions: a baseline and three intention conditions (expectation, execution 1 and 2). In the expectation condition, subjects were asked to make a new response to intented stimuli during ongoing task, but the intented stimuli never occurred. In the execution 1 (one type of expected stimulus) and 2 (two types of expected stimuli), the intended stimuli did occur in 20% of trials. The reaction time and error rate were calculated in each condition. Repeated measures using ANOVA of subject's mean reaction times (RTs) and mean error rates (ERs) showed main effects of conditions during ongoing task. The comparison of PM tasks in executive condition 1 and 2 also showed significance in RTs and ERs. This paradigm reflects sufficiently the performance of prospective memory function during ongoing task in normal individuals. Thus, we suggest that the paradigm will be helpful to study neural network of PM function using brain imaging techniques and diagnosis of PM dysfunction.

• 한국운동역학회지
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• 제17권2호
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• pp.187-196
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• 2007

The purpose of this study was to find the most effective movement pattern from three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion task, which had the time constraint to complete the performance. 7 healthy subjects participated in left and right side movement task by an external signal, which required the subject to perform the task as fast as possible. Mechanical output and joint kinetics focusing on the lower extremities were analyzed. The results were as follows. In spite of the shortest duration in propulsive phase, the hopping condition showed no difference with other conditions in the work output done and take-off velocity. It resulted from the greatest power output generated during the propulsive phase. A significant difference was found for joint moment and joint power according to the movement conditions. The joint moment and joint power for the countermovement and hopping conditions were larger than those in the squat condition. This was speculated to be due to the extra power that could be generated by the pre-stretch of muscle in preparation for the propulsion. The hopping condition which had substantially more pre-stretch load in the preparatory eccentric phase produced considerably more power than countermovement condition in the propulsive concentric phase. Furthermore during the hopping a large amount of joint moment and joint power could be produced in a shorter time. Therefore it was deemed that the hopping movement is an effective type of preparatory movement which takes much more advantage of the pre-stretch than any other movement.

• Physical Therapy Rehabilitation Science
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• 제6권3호
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• pp.134-139
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• 2017

Objective: Dual-task interference is defined as decrements in performance observed when people attempt to perform two tasks concurrently, such as a verbal task and walking. The purpose of this study was to investigate the changes of gait ability according to the dual task interference in chronic stroke survivors. Design: Cross-sectional study. Methods: Ten chronic stroke survivors (9 male, 1 female; mean age, 55.30 years; mini mental state examination, 19.60; onset duration, 56.90 months) recruited from the local community participated in this study. Gait ability (velocity, paretic side step, and stride time and length) under the single- and dual-task conditions at a self-selected comfortable walking speed was measured using the motion analysis system. In the dual task conditions, subjects performed three types of cognitive tasks (controlled oral word association test, auditory clock test, and counting backwards) while walking on the track. Results: For velocity, step and stride length, there was a significant decrease in the dual-task walking condition compared to the single walking condition (p<0.05). In particular, higher reduction of walking ability was observed when applying the counting backward task. Conclusions: Our results revealed that the addition of cognitive tasks while walking may lead to decrements of gait ability in stroke survivors. In particular, the difficulty level was the highest for the calculating task. We believe that these results provide basic information for improvements in gait ability and may be useful in gait training to prevent falls after a stroke incident.

• 한국전문물리치료학회지
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• 제21권4호
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• pp.34-39
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• 2014

The purpose of this study was to examine the effect of three cognitive tasks on gait at a preferred walking speed, and at a fast speed, using dual-task methodology. A total of 29 stroke patients participated in the study. All 29 subjects performed 2 motor tasks (10-meter walk task and timed up and go task each at a preferred and a fast speed) and three cognitive tasks [Stroop, word list generation (WLG), serial subtraction (SS)] under dual-task conditions [cognitive-motor interference (CMI)] in a randomized order. Gait speeds were measured in six different conditions. A repeated-measure analysis of variance was employed to compare the results of the Stroop training, WLG, and SS tasks during preferred and fast walking. A Bonferroni adjustment use for post hoc analysis. The level of statistical significance was set at ${\alpha}=.05$. A CMI effect occurred for performance of a 10-meter walking task at two different speed and a cognitive task (p<.05). Stroop had a significantly greater effect than SS and WLG (p<.05). The timed up and go task was affected when performed with fast walking speed during Stroop cognitive task (p<.05), but was not affected if performed with preferred walking speed during a cognitive task (p>.05). This study showed that CMI of Stroop can be used as a rehabilitation program for stroke patients.

• 대한수학교육학회지:학교수학
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• 제18권4호
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• pp.749-771
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• 2016

이 논문에서는 우리나라와 미국 수학 교과서에서 다루고 있는 평행사변형이 되기 위한 조건 관련 과제를 과제의 구조, 증명과 추론 유형, 그리고 인지적 노력 수준에 따라 비교 분석하였다. 이를 통해 두 나라 교과서 과제의 공통점과 차이점을 분석하였다. 그 결과는 다음과 같다. 첫째, 과제 구조와 관련하여, 우리나라 교과서에 비해 미국 교과서에 제시된 과제의 구조가 더 다양하다. 둘째, 증명과 추론 유형과 관련하여, 우리나라와 미국 교과서 모두 IC 과제와 DA 과제의 구성 비율이 높으며, 우리나라 교과서에 비해 미국 교과서에 제시된 과제의 유형이 더 다양하다. 셋째, 과제의 인지적 노력 수준과 관련하여, 우리나라와 미국 교과서 모두 PNC 과제와 PWC 과제가 대부분을 차지하며, 우리나라의 경우 미국에 비해 구체적인 알고리즘적 절차를 이용하는 수학 과제를 제시하는 비율이 높다. 차이점을 토대로 우리나라 교과서 재구성에 필요한 다음과 같은 시사점을 얻을 수 있었다. 첫째, 과제의 구조 및 증명과 추론 유형과 관련하여, 구성의 다양성을 높여야 한다. 둘째, 과제의 인지적 노력 수준과 관련하여, PNC 과제에 대한 편중현상을 완화해야 하며, 과제 유형별 인지적 노력 수준에 대한 재고가 필요하다. 셋째, 과제의 주제 또는 소재와 관련하여, 수학 내적, 외적인 상황과의 연결성이 강화된 과제를 도입할 수 있는 방안의 재고가 필요하다.

• 한국정보통신학회논문지
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• 제10권5호
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• pp.783-791
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• 2006

전자무역에서 실시간 시스템은 매우 중요한 역할을 담당한다. 각각의 태스크들은 제한된 시간이 주어져 있고, 제한된 시간 내에 문서 처리를 수행하지 못할 경우 큰 피해를 입을 수 있으므로 반드시 약속된 규정이 지켜져야 한다. 전자무역에서 스케줄링 가능성 기법들은 주로 주기적인 태스크를 사용하는데 이 방법 외의 다른 태스크 시간 조건과 비 주기적인 태스크 시간조건을 이용하여 보다 안정적인 사전예측 스케줄링 가능성 알고리즘의 연구가 필요하다. 본 논문은 개별 태스크 이용율을 사용하여 예측가능성을 높이기 위한 알고리즘을 제안하며, 기존의 태스크 전체 이용율과 제안한 알고리즘을 이용한 스케줄링 가능성 조건을 제시하였다.

• 대한인간공학회지
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• 제21권1호
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• pp.95-112
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• 2002

Two experiments were carried out to compare the suitability in visual tasks between cathode-ray tube (CRT) and thin film transistor-liquid crystal display (TFT-LCD). In the first experiment, the subjects were requested to detect pre-assigned target words or icons among distracters presented under time-invariant (static) image mode. The subjects' visual performance and fatigue were assessed while carrying out search tasks with dim and bright ambient light conditions. Significant interaction effects were found among displays, task types, and ambient light conditions. Due to visual fatigue, the subjects' accommodative power decreased in the end of task and the degradation was more significant for the CRT users and under bright ambient light. IN the second experiment, the subjects performed information processing task with time-varying road signs at a driving simulator to assess interaction effects between display types and changing speed of dynamic image. The perception time using TFT-TCD was shorter under slow image change while that of CRT was shorter rapid image change. Findings from this study suggest that, to improve visual task performance, users should carefully select their visual display type depending on the task to be performed.