In order to study event-related desynchronization (ERD) related to voluntary movement, we designed two experiments. In the first experiment, untrained subjects were required to imagine the action of typing with left or right index finger for about 1 second before real action, whereas they were required to type instantly after instruction in the second experiment. By analyzing spontaneous EEG signals between the instruction and the action, we predicted which finger was used. The prediction accuracy in the first experiment fell from 85% to 71% with the progress of experiment, the average accuracy being 78%, whereas the prediction result was almost random guess in the second experiment. The results demonstrate that (1) ERD patterns are significantly affected by the effective duration of motion imagination, (2) unconscious reduction of this duration can decrease the prediction accuracy. Therefore, when designing subsequent BCI experiments, we should devote our attention to the question of how to keep the effective duration of motion imagination.
Brain ; physiology ; Cortical Synchronization ; Electroencephalography ; Humans ; Man-Machine Systems ; Task Performance and Analysis ; User-Computer Interface

Using human electroencephalogram (EEG) to control external devices in order to achieve a variety of functions has been focus of the field of brain-computer interface (BCI) research. P300 is experiments which stimulate the eye to produce EEG by using letters flashing, and then identify the corresponding letters. In this paper, some improvements based on the P300 experiments were made??. Firstly, the matrix of flashing letters were modified into words which represent a certain sense. Secondly, the BCI2000 procedures were added with the corresponding source code. Thirdly, the smart car systems were designed using the radiofrequency signal. Finally it was realized that the evoked potentials were used to control the state of the smart car.
Adult ; Automobiles ; Brain ; physiology ; Brain-Computer Interfaces ; Electroencephalography ; instrumentation ; methods ; Event-Related Potentials, P300 ; Evoked Potentials, Visual ; Female ; Humans ; Male ; Man-Machine Systems ; Task Performance and Analysis

Pushing and pulling (P&P) is a common operating mode of operator's physical works, and plays an important role in evaluation of human behavior health and operation performance. At present, there are many research methods of P&P, and this article is a state-of-art review of the classification of P&P research methods, the various impact factors in P&P program, technical details of internal/external P&P force measurement and evaluation, the limitation of current research methods and the future developments in the ergonomics field.
Biomechanical Phenomena ; Ergonomics ; methods ; Hand Strength ; physiology ; Humans ; Low Back Pain ; prevention & control ; Physical Exertion ; Posture ; physiology ; Task Performance and Analysis ; Weight-Bearing ; physiology

OBJECTIVES: The aim of this study was to estimate musculo-skeletal symtoms of municipal sanitation workers and to evaluate working conditions of municipal sanitation workers to search for the factors related to musculo-skeletal symptoms. METHODS: We conducted a descriptive cross-sectional survey. The study subjects were comprised of 543 municipal sanitation workers in some divisions of Seoul and the Gyeonggi province. Musculo-skeletal analysis was done by using the modified criteria of NIOSH musuclo-skeletal symptoms, RULA and, REBA. Statistical analysis was done by using the chi-square test, multiple logistic regression analysis. RESULTS: 72.2% of the subjects complained musculo-skeletal symptoms (39.6% on the upperlimbs, 30.0% on the lumbar region, 27.4% on the legs). For the musculo-skeletal symptoms criteria (1~3), street cleaners complained of more musculo-skeletal symptoms than the solid waste collectors, after classifying the jobs of sanitation workers. On logistic regression analysis of the musculo-skeletal "symptoms criteria1" positive groups, age was related to the criteria positive (prevalence odds ratio=1.018, 95% CI: 0.993-1.046). The worktime was significantly related to 'criteria positive 1 and, 2' (prevalence odds ratio=2.165 (95% CI: 1.156-4.131), 2.187 times (95% CI: 1.071-4.651)). The RULA score, the subtotal A score of RULA, the REBA score and , the total A REBA score of the upperlimbs of solid waste collectors were higher than those of the street cleaners. CONCLUSIONS: In spite of the lower ergonomic evaluation score of the street cleaner, the street cleaners complained of more musculo-skeletal symptoms than did the solid waste collectors due to more frequent repetitive motions, a longer work time (over 10 hours) etc. It is suggested that the sanitation workers need to use the proper methods to avoid musculo-skeletal disease.
Cross-Sectional Studies ; Human Engineering ; Humans ; Logistic Models ; Lumbosacral Region ; National Institute for Occupational Safety and Health (U.S.) ; Sanitation ; Solid Waste ; Task Performance and Analysis ; Upper Extremity

Ergonomics ; Humans ; Occupational Health

Ergonomics ; Occupational Health

Study in the field of sleep and memory has greatly expanded recently and the number of publications supporting the association between sleep and memory consolidation is rapidly growing. This study presents evidence related to sleep-dependent memory consolidation, ranging from behavioral task-performing studies to molecular studies, and several arguments against the association. Basic researches show that many genes are upwardly regulated during sleep and patterns of brain activation seen during daytime task training are repeated during subsequent REM sleep. Several electrophysiological studies demonstrate the correlation between spindle density increase following training and subsequent improvement in performing the training task. Overnight improvement or deterioration in task performance correlates with REM or SWS sleep. In the end, a lot of issues remain to be studied and discussed further in the future in spite of supporting evidence now available.
Brain ; Memory* ; Sleep, REM ; Task Performance and Analysis

PURPOSE: The purpose of this study was to identify the effects of the social support and ego-resilience on the nursing performance among hospital nurses. METHODS: The subjects of this study were 369 nurses in a senior general hospital. We used the self-reported questionnaire to assess the level of ego-resilience, social support and nursing performance of hospital nurses. The data were analyzed using descriptive statistics, frequency, t-test, ANOVA, Pearson's correlation coefficient and stepwise multiple regression. RESULTS: This study showed the positive relationship between the social support and ego-resilience on tne the nursing performance of hospital nurses. The higher group of the social support and ego-resilience showed the more performance of hospital nurses. And, the influencing factors on the performance are age, ego-resilience, social support, night working days a month in the order. CONCLUSION: Further studies will be needed to promote the performance of nurse in hospital and policies to be develop to elevate the social support and ego-resilience of nurses.
Hospitals, General ; Surveys and Questionnaires ; Task Performance and Analysis

PURPOSE: The purpose of this study was to investigate the balance confidence and balance ability among community-residing stroke patients. METHODS: The sample for this study was a convenience sample obtained from patients who visited welfare centers for the disabled in three cities from October to December in 2009. The Activities-specific Balance Confidence Scale and Berg Balance Scale were used to measure confidence in task performance and balance ability. RESULTS: The level of balance confidence and balance ability were low in these subjects. There was a significant relationship between balance confidence and balance ability (r=.424, p=.000). Subjects with less balance ability felt less balance confidence. CONCLUSION: Among community-residing stroke patients, falls are common. Falls prevention which may contribute to the incidence of fall and fall related injury should be part of stroke rehabilitation plan. Also, it is necessary that an intervention for falls prevention after stroke should take into account factors such as the balance confidence and balance ability.
Humans ; Incidence ; Stroke ; Task Performance and Analysis

OBJECTIVES: Euthymic patients with bipolar disorder have been reported to show deficits in sustained attention. This study aimed to compare the attention capacities of euthymic bipolar patients with those of control subjects using the sustained attention to response task (SART) and to examine the differences in the performance of SART related to the type of the stimulus. METHODS: The four SART tasks were performed to measure attention capacities in 42 euthymic patients with bipolar disorder and 28 control subjects. Happy, neutral, fearful faces and digit '3' were used as target stimuli in happy, neutral, fear and digit task conditions, respectively. The severity of mood symptoms was assessed with 17-item Hamilton Rating Scale for Depressive symptoms and Young Mania Rating Scale for manic symptoms. The efficiency estimate which reflects both the response accuracy and speed was used as the main outcome variable. RESULTS: Bipolar patients showed significantly lower correct response rate than control group in all task conditions. Efficiency estimates of the bipolar patient group were significantly lower than those of the control group in the SART using facial stimuli, but not in the digit task condition. There was no significant difference in task performances related to the emotional categories of facial stimuli. CONCLUSION: Bipolar patients showed deficits in sustained attention even in the euthymic state. The attention deficits shown in the euthymic bipolar patients may be prominent in a more complex task condition with stimuli such as facial stimuli.
Bipolar Disorder ; Depression ; Humans ; Task Performance and Analysis