• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.130-134
• /
• 1992

The ability of a robot system to comply to an environment via the control of tool-environment interaction force is of vital for the successful task accomplishment in many robot application. This paper presents the implementation of external force control for two dimensional contour following task using a commercial robot system. Force accommodation is used since a constraint imposed in our work is not to modify the commercial robot system. A linear, decoupled model of two dimensional contour following system in the discrete time domain is derived first. Then the experimental verification of linear control is obtained using a PUMA 560 manipulator with standard Unimation controller, Astek FS6-120A six axis wrist force sensor attached externally to the arm and LSI-11173 microcomputer. Experimentally obtained data shows that the RMS contact force error is 0.8246 N when following the straight edge and 2.3768 N when following 40 mm radius curved contour.

• Journal of the Korean Home Economics Association
• /
• v.33 no.3
• /
• pp.71-84
• /
• 1995

The purpose of this study is to investigate the effect of wives' demographic variables, the family cohesion and adaptability perceived by dual-career wives on household task performance. The subject of this study were 391 employed professional wives working in seoul. Using the questionnary, the data was obtained and the data was analysed by percentile, frequency, ANOVA, multiple regression. The results were as follows. 1) the family cohesion and adaptability scores showed a little higher than those of previous research. Number of children, age of the youngest child and family pattern were statistically significant in the family cohesion, number of children and family pattern were statistically significantly in the family adaptability. 2) The division of housework by family members was influenced by the family adaptability and family pattern. The family cohesion was a significant determinant of the division of housework by husband. The standard of housework was influenced by wives' age, the family cohesion and a housework time.

• Journal of Dairy Science and Biotechnology
• /
• v.27 no.2
• /
• pp.49-53
• /
• 2009

• Nuclear Engineering and Technology
• /
• v.40 no.7
• /
• pp.615-624
• /
• 2008

In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1 %), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.2758-2768
• /
• 2014

A research on differential effects of task and relationship conflicts claims positive effects of task conflict on innovation performance and negative effects of relation conflict on innovation performance. Yet, given the intimate interconnectedness of task conflict and relation conflict, task conflict, which has a beneficial impact on innovation performance, may have adverse effects on innovation performance as it goes through the process of being transferred to relation conflict. That necessitates the need for a way of management that can undermine the process of transference of task conflict to relation conflict, and team identification, which is a social identity of an individual and also a sort of positive, affective or cognitive bonds of such individual toward the team, can be an effective way of managing conflict. The research, which was conducted based on materials collected from 213 employees, confirms that such theory holds true for the real-life business environment. Based on the findings, this study suggested implications and directions for future research.

• Communications for Statistical Applications and Methods
• /
• v.8 no.1
• /
• pp.193-207
• /
• 2001

When designing a test set, we need to consider constraints on items that are deemed important by item developers or test specialists. The constraints are essentially on the components of the test domain or abilities relevant to a given test set. And so if the test domain could be represented in a more refined form, test construction would be made in a more efficient way. We assume that relationships among task abilities are representable by a causal model and that the item response theory (IRT) is not fully available for them. In such a case we can not apply traditional item selection methods that are based on the IRT. In this paper, we use entropy as an uncertainty measure for making inferences on task abilities and developed an optimal item selection algorithm which reduces most the entropy of task abilities when items are selected from an item pool.

• Journal of Biomedical Engineering Research
• /
• v.28 no.3
• /
• pp.417-422
• /
• 2007

In this study, we investigated spatio-temporal eye-hand coordination by the "Global effect paradigm", a target-distracter configuration Global effect is observed a variety of visual tasks, for example, during rapid automatic tracking, scanning for target detail, and the comparison of target configurations. Global effect used to investigate eye-hand coordination with a task that presents a target close to a distracter. Eight young subjects participated in the experiments. The experiments consist of using a distracter less eccentric than the targe1 and using a distracter more eccentric than target. Each experiment consist of tasks which are making reference, pointing the target with watching visual stimulation(saccade) and pointing the target. The subject's task was to move towards the target as quickly as possible. We measured the eye movement by using EOG and the hand movement by using NDI Optotrak system. This study shows that eye and hand movement exists for global effect paradigm in spatio-temporal coordination.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.4
• /
• pp.254-261
• /
• 2014

BACKGROUND: This study was conducted to investigate effects of silicate fertilizer application on red pepper (Capsicum annuum L.) productivity with improving soil chemistry under plastic film house in paddy field. METHODS AND RESULTS: The silicate fertilizer was applied as 0, 100, 200, and 300 kg/10a as basal dressing before transplanting pepper plant seedlings. Cultivar of the pepper plant was Cheon-Ha-Dae-Se. Amounts of inorganic fertilizer applied as $N-P_2O_5-K_2O$=19.0-6.4-10.1kg/10a was estimated depending on soil test values. After applying 50% of nitrogen, 100% of phosphorus, and 60% of potassium fertilizers as basal dressing, the seedlings of pepper plant were transplanted. The rests of nitrogen and potassium fertilizers were applied as side-dressing after the first, second, and fourth harvests of red pepper. When comparing selected chemical properties of soils between before transplanting and after final(the fifth) harvest, soil pH, available $P_2O_5$, and exchangeable $Ca^{2+}$ increased with increasing the applications of silicate fertilizer, whereas electrical conductivity(EC) decreased. However, exchangeable $K^+$ was higher with the treatments of 100 and 200 kg/10a, and exchangeable $Mg^{2+}$ was higher with 300 kg/10a application. In addition, nitrogen and phosphorus concentrations of red pepper collected from the first harvesting stage decreased with increasing the applications of silicate fertilizer, but potassium, calcium, and magnesium concentrations in red pepper were highest with 300 kg/10a application. Yield of red pepper increased between 9.0 and 11.8% with the applications of silicate fertilizer. Marketable fruit rate of res pepper was highest(97.3%) with 200 kg/10a application. CONCLUSION: The application of silicate fertilizer as basal dressing in paddy-converted fields improved soil chemistry and increased red pepper productivity.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.1
• /
• pp.75-86
• /
• 2011

This paper describes several current research activities and the field techniques for the prevention of human errors during the operation of nuclear power plants(NPPs). The human aspects such as 'fitness for the duties', 'job competence and suitability', 'types of communication', 'behaviors of field workers', 'teamwork of main control room crews', 'task procedures', etc. have been investigated for improving the performance of operating personnel in NPPs. We decide to develop a set of the complementary techniques for the reduction of human errors. The set of techniques developed includes teamwork criteria, jobs fitness analysis, procedure enhancement guide, 3-way communication, campaign posters, a behavior based safety program, a procedure guideline, and a task hazard identification method for the field practitioners in NPPs. These can offer a set of significant human error countermeasures to be considered for analyzing and reducing human error in NPPs as well as other fields of industry.

• ETRI Journal
• /
• v.29 no.3
• /
• pp.259-269
• /
• 2007

The ubiquitous flexible operating system (UbiFOS) is a real-time operating system designed for cost-conscious, low-power, small to medium-sized embedded systems such as cellular phones, MP3 players, and wearable computers. It offers efficient real-time operating system services like multi-task scheduling, memory management, inter-task communication and synchronization, and timers while keeping the kernel size to just a few to tens of kilobytes. For flexibility, UbiFOS uses various task scheduling policies such as cyclic time-slice (round-robin), priority-based preemption with round-robin, priority-based preemptive, and bitmap. When there are less than 64 tasks, bitmap scheduling is the best policy. The scheduling overhead is under 9 ${\mu}s$ on the ARM926EJ processor. UbiFOS also provides the flexibility for user to select from several inter-task communication techniques according to their applications. We ported UbiFOS on the ARM9-based DVD player (20 kB), the Calm16-based MP3 player (under 7 kB), and the ATmega128-based ubiquitous sensor node (under 6 kB). Also, we adopted the dynamic power management (DPM) scheme. Comparative experimental results show that UbiFOS could save energy up to 30% using DPM.