• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.103-108
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• 2005

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.197-204
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• 2008

The purpose of this paper was to develop a rehabilitation training system which is controlled by electric currents to the Magneto-Rheological dampers system. This system provided the function for the training of the unbalance of the lower extremities. 10 subjects executed the tracing and moving exercises which are presented through the display monitor and confirmed own the capability of performance on the task. The electromyographies of the four muscles in lower extremities were recorded and analyzed in the time and frequency domain the muscles of interest were rectus femoris, biceps femoris, gastrocnemius, tibialis anterior. The experimental results showed that subjects had a task under feedback mode then subjects improve the capability of performance, increasing the in time, decreasing the out time and the distance of body shift. The moving average EMG, spectral energy of four muscle is lower the feedback mode than the constant mode. This could aid the hemiplegic patients to train more easily.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.130-134
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• 2008

Touch screen phone which is expected to play a big part of the mobile market for the next few years, has many merits but demerits of inaccurate feedback. It offers audio and tactile feedback to strengthen the weak point. This study aims to see if audio feedback and vibration feedback react upon each other under realistic conditions. We had a qualitative research in perception after using touch screen phone feedback. The result showed that with any feedback users were satisfied more than without any feedback and there was diversity in response. We ran the study again to see the performance level and the projective workload between the kind of feedback and interrupting feedback environment Performance rates were faster with audio feedback and according to the projective workload assessment users felt that task was easier and less annoying with audio-vibration feedback. The results suggest that audio feedback could be more effective than vibration feedback. A future study will figure out the relationship between the factors of qualitative-controlled feedback and learning time and the performance, and the main cause to make people prefer one feedback over another in a realistic world.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.225-234
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• 2021

Due to pandemic situations, the development of home robots that can make the house an optimized space for various activities is active. This study aims to confirm the effectiveness of approach or avoidance behavior for feedback positioning on the user experience, depending on the context in which the robot performs the task. Based on two types of the task contexts(Reactive vs. Proactive) and three types of robot feedback positioning(No move vs. Avoidance vs. Approach), six different scenarios were designed for experimental study. Likeability, perceived intelligence, rapport, negative attitude and predictability of behavior are measured for each conditions. The result showed the main effects of perceived intelligence, rapport, predictability in the context of tasks, and of likability, perceived intelligence, rapport in robot feedback positioning. The interaction effects were shown in likeability and perceived intelligence. In conclusion, approach-avoidance experiences can also be applied to robot behaviors as well, and the negative effects of avoidance have been significantly confirmed.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.2
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• pp.146-154
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• 2018

Purpose: In this study, effects of positive, negative, and mixed verbal feedback were examined for accuracy of self-assessment, emotional responses, self-efficacy, and perceived quality of feedback in skill performance assessment. Methods: Participants were a convenience sample of 104 second-year nursing students who had completed their fundamentals of nursing class. Participants were assigned randomly to a positive, a negative or a mixed feedback group. All participants completed the performance measure and then received the assigned the type of feedback from an evaluator. After delivery of feedback, they assessed their own performance using the same sheet as the evaluator and completed the survey for emotional response, self-efficacy for learning, and quality of feedback. Results: There were no significant differences in accuracy of self-assessment and perceived quality of feedback among the three groups ($x^2=4.74$, p=.094; $x^2=3.30$, p=.192, respectively). The negative feedback group had significantly lower self-efficacy and positive emotions and more negative emotions than the other two groups (F=9.43, p=.009; $x^2=16.29$, p<.001; $x^2=5.69$, p=.005, respectively). Conclusion: Negative feedback can affect emotions and motivations for learning in nursing students and may interfere with the effectiveness of feedback, so instructors should pay more attention when providing negative feedback. Mixed feedback with an effect similar to positive feedback could be an alternative.

• The Journal of Korean Society for Neurotherapy
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• v.22 no.3
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• pp.25-29
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• 2018

Purpose In this study, 45 students were divided into task - oriented group, task - oriented intermittent group, and continuous group, and the effect of each variable on learning was changed to angle of the arms' we checked. Methods This study was conducted for 45 days from March 13 to 18, 2017 for five days in the 20 generals living in Changwon city. Dart and goniometer were used for the measurement. In the exercise program, darts were placed on a smooth, hard surface of 1.5M height and the distance to the subject was set 1.5m away. In the dart throw practice, all three groups were marked with an elbow flexion $30^{\circ}$ on the wall, and the subjects were instructed to throw the dart at that point. Results Comparisons between groups showed significant differences between the continuous task-oriented training group and the intermittent task-oriented training group and the control group at the end of training (*** P <0.001). Conclusion This study showed that the intermittent task-oriented training method showed the highest effect (*** P <0.001), which proved that the intermittent method is the most effective exercise method among the three groups.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.59-68
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• 2013

Objective: The purpose of this paper is to introduce a task complexity model combining task design aspects and complexity dimensions and to explain an approach to identifying and organizing task complexity factors based on the model. Background: Task complexity is a critical concept in describing and predicting human performance in complex systems such as nuclear power plants(NPPs). In order to understand the nature of task complexity, task complexity factors need to be identified and organized in a systematic manner. Although several methods have been suggested for identifying and organizing task complexity factors, it is rare to find an analytical approach based on a theoretically sound model. Method: This study regarded a task as a system to be designed. Three levels of design ion, which are functional, behavioral, and structural level of a task, characterize the design aspects of a task. The behavioral aspect is further classified into five cognitive processing activity types(information collection, information analysis, decision and action selection, action implementation, and action feedback). The complexity dimensions describe a task complexity from different perspectives that are size, variety, and order/organization. Combining the design aspects and complexity dimensions of a task, we developed a model from which meaningful task complexity factors can be identified and organized in an analytic way. Results: A model consisting of two facets, each of which is respectively concerned with design aspects and complexity dimensions, were proposed. Additionally, twenty-one task complexity factors were identified and organized based on the model. Conclusion: The model and approach introduced in this paper can be effectively used for examining human performance and human-system interface design issues in NPPs. Application: The model and approach introduced in this paper could be used for several human factors problems, including task allocation and design of information aiding, in NPPs and extended to other types of complex systems such as air traffic control systems as well.

• English Language & Literature Teaching
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• v.13 no.1
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• pp.1-26
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• 2007

This study aimed to investigate how EFL learners perceived English writing tasks and teachers' written feedback. The subjects were 82 mixed major college EFL students aged 19-24; the majority were freshmen females. Based on the scores estimated from the essay evaluation test, they were placed into two groups (proficienand less-proficient writers) and responded to an in-class questionnaire. The results indicated that: (1) regardless of writing proficiency, a large number of the students felt that they were just fair writers, which could be derived from low confidence and high anxiety; (2) grammar and vocabulary were perceived as the main features that determined good EFL writers and also prevented the students from performing the writing task successfully; (3) they believed that teachers' feedback contributed to the development of their English writing skills because it helped them apprehend what to improve or avoid in the future, acquire better English usage, and correct their errors; and (4) the proficient writers were more willing to correct errors themselves after being provided clues than the less-proficient writers. Implications of the findings for EFL classrooms are discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1523-1526
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• 1996

This paper presents a new method of force reflection in the teleoperated mobile robot control: artificial force feedback. Generally it is well known that force feedback from slave to master increases the reality with which the operator interacts with the environment. In the applications of the teleoperated mobile robot, however, such a force feedback control algorithm has rarely appeared in the literature because the contact force between the environment and the mobile robot is not available. In this paper, a method of artificially generating the feedback force for the teleoperated mobile robot is presented in order to improve the task performance. The computed artificial force feeds into the new designed joystick so as to increase the telepresence of the environment. Through simulations, we confirm the validity and effectiveness of our algorithm.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.173-175
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• 2007

The lexical decision task (LDT) commonly postulates the activation of semantic level. However, there are few studies for the feedback effect from semantic level. The purpose of the present study is to investigate whether the feedback effect from semantic level is facilitatory or inhibitory in Korean LDT. In Experiment 1, we manipulated the number of phonological syllable neighbors (PSN) and the number of semantic neighbors (SEN) orthogonally while orthographic syllable neighbor (OSN) is dense. In the results, the significant facilitatory effect was shown in words with many SEN. In Experiment 2, we examined same conditions as Experiment 1 but OSN was sparse. Although the similar lexical decision latency pattern was shown, there was no statistical significance. These results can be explained by the feedback activation from semantic level. If a target has many SENs and many PSNs, it receives more feedback activation from semantic level than a target with few SENs and PSNs.