• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.819-824
• /
• 1997

This paper presents a cell-based motion control strategy for soccer playing mobile robots. In the central robot motion planner, the planar ground is divided into rectangular cells with variable sizes and motion indices to which direction the mobile robot should move. At every time the multiple objects-the goal gate, ball, and robots-detected, integer values of motion indices are assigned to the cells occupied by mobile robots. Once the indices being calculated, the most desirable state-action pair is chosen from the state and action sets to achieve successful soccer game strategy. The proposed strategy is computationally simple enough to be used for fast robotic soccer system.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.751-760
• /
• 2017

This paper proposes a point of common coupling (PCC) voltage compensation algorithm using a current limitation strategy for use in distributed generation (DG). The proposed strategy maintains the PCC voltage by prioritizing currents when an output current reference is larger than the current capacity of the power condition system (PCS) of the DG. With this strategy, the DG outputs the active current, reactive current, and the negative sequence current. The DG uses the reactive current for maintaining the PCC voltage within a normal range; the negative sequence current is used for reducing the PCC voltage unbalance. The proposed method was verified using PSIM simulation and experimental results.

• Journal of Families and Better Life
• /
• v.15 no.1
• /
• pp.13-26
• /
• 1997

The study was to explore the housework time management strategies and time spent in housework of employed wives and to understand the variables influenced on them. The samples were composed of 271 employed wives living in Chunlabuk-Do. The results were as follows: 1) The employed wives spends average 4.5 hours a day on the housework. The significant differences were ground in the housework time related to all demo-graphic variables. 2) The level of the housework time management strategies of employed wives was lower than the average. The most influential variable on the housework time management strategies of employed wives was the level of education the monthly income and employment types. A employed wives with the higher work status education level and income level utilized more efficient time strategies. 3) The major strategy which influences the housework time is that of simplification. Especially occupation of housewives and type of house interact with the strategy of sim lification. That is as the housewives with the jobs of blue-collar production-technology and clergycal technology use the simplification strategy much their amount of housework time was reduced.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.6
• /
• pp.24-29
• /
• 2001

Adaptive valve timing control is one of the promising techniques to accomplish the optimized mixture formation and combustion depending on the load and speed, which is needed to meet the future challenges in reducing fuel consumption and exhaust emissions. The behavior and the effect of adaptive valve timing control system has been investigated by computer simulation, which simulates the gas dynamics in engines. Improved fuel economy can be achieved by reduction of pumping loss under low and mid load conditions. EIVC(Early Intake Valve Closing) strategy turns out to be superior to LIVC(Late Intake Valve Closing) strategy in reducing fuel consumption. Deterioration of combustion quality can be overcome by introducing LIVO(Late Intake Valve Opening) strategy, which increases turbulent intensity in cylinders. Furthermore, LIVO can reduce HC emission by decreasing the required amount of fuel to be injected during cold start.

• Journal of Mechanical Science and Technology
• /
• v.15 no.11
• /
• pp.1482-1489
• /
• 2001

Thermally-induced errors originating from machine tool errors have received significant attention recently because high speed and precise machining is now the principal trend in manufacturing proce sses using CNC machine tools. Since the thermal error model is generally a function of temperature, the thermal error compensation system contains temperature sensors with the same number of temperature variables. The minimization of the number of variables in the thermal error model can affect the economical efficiency and the possibility of unexpected sensor fault in a error compensation system. This paper presents a thermal error model with minimum number of variables using a fuzzy logic strategy. The proposed method using a fuzzy logic strategy does not require any information about the characteristics of the plant contrary to numerical analysis techniques, but the developed thermal error model guarantees good prediction performance. The proposed modeling method can also be applied to any type of CNC machine tool if a combination of the possible input variables is determined because the error model parameters are only calculated mathematically-based on the number of temperature variables.

• Journal of Power Electronics
• /
• v.19 no.3
• /
• pp.803-814
• /
• 2019

This paper proposes a three-phase current balancing strategy in a power transmission system employing distributed static series compensators (DSSCs). With the proposed variable quadrature voltage injection method, the DSSC emulates either an inductive or a capacitive impedance into the transmission line, and the magnitudes of the phase currents are balanced. Hence, the phase imbalances in the power transmission system are significantly reduced. As a result, the power transfer capability of the transmission lines can be improved. The operational principle of the DSSCs, the hardware structure and the control algorithm are described in detail. Finally, the theoretical analyses and the proposed strategy are experimentally verified through a scaled down transmission system with DSSC prototypes.

• Journal of Information Technology Applications and Management
• /
• v.29 no.2
• /
• pp.39-50
• /
• 2022

This research confirmed whether banks and saving banks increase their deposit margin under changes in the base rate. This paper has conclusions as follows. First, when the Bank of Korea changes the base rate, deposit rate variable are significant with panel analysis in the total data set and saving banks. This result implies that changes in the base rate affect deposit margin. Second, this study confirmed whether banks and saving banks maximize their deposit margin as base rate changes. As a result, when the Bank of Korea cut the base rate, the deposit margins of banks and saving banks decreased significantly. Still, their deposit margins are not statistically significant in the opposite situation. Therefore, this paper could not find evidence that banks and saving banks behave to maximize their deposit margin. Maybe, this phenomenon can appear because these financial institutions recognize this criticism.

• Journal of Korean Society of Transportation
• /
• v.11 no.1
• /
• pp.87-103
• /
• 1993

The subject this paper is the signal control strategy under oversaturated conditions. The nature of traffic control for oversaturation is essentially different from the standard control modes. While under non-saturated situation traffic control is needed for the sake of safety and efficiency, the throughput is essential under oversaturated conditions. Therefore berth objective and strategies differ. For an oversaturated stream the cycle time and the signal offset are thought to be of rather secondary importance. For this case the green split may well be the most important control variable to serve the excessive demand. Up to now, however, most efforts have concentrated on the strategy with the concept which lies just on the extension of Webster's. "Green-split Coordination Strategy for Over-Saturated Networks", presents newly contrived three types of strategies named Forward-coordination, Backward-coordination and Network-coordination respectively and describes the algorithms with the evaluations. The forward coordination strategy treats the forward wave of flow between two signals. The aim is to prevent the outbreak of queue due to the accumulation of temporary excess of demand in near-saturation or saturation flow. The backward coordination strategy treats the backward rave of flow between two signals. The goal is to prevent the waste of green time caused by the exit block at the upstream signal. for this purpose a feedback regulation is provided of the upstream green-split so that the inflow-outflow balance is kept zero. The resultant surplus of green time is alloted to other signal stages. Also here the examination is made of the appropriate value of the feedback control parameter. The network coordination strategy is operated to maximize the network throughput in a specific direction applying a bang-bang control at the bottleneck intersection. This is a type of intervenient control for policy reasons. For this strategy the green-split coordinations, particuarly the backward coordination, are essential as the tactical elements. In order to evaluate the preposed strategies those are compared with the latest existing strategy called saturation-degree-ratio control by the simulation experiments in an assumed 4$\times$4 grid network. The results are satisfactory showing a 10-15% reduction in delays and a 15% increase in network capacity.

• Journal of Korean Society for Quality Management
• /
• v.41 no.4
• /
• pp.611-621
• /
• 2013

Purpose: The purpose of this study was to investigate if companies' efforts of quality management practices have positive impacts on the companies' performance as the first stage. In the second stage of this study, we tried to confirm if the degree of companies' making efforts on customization strategy and R&D strategy function as moderate variable on relationship between quality management practices and companies' performance. Methods: The collected data through survey were analysed using multiple regression for the first stage of the study and moderate regression for the second one of it. Results: The results of this study are as follows; quality management practices have positive effect on performances. Moreover, much effort on customization strategy has significant moderate effect on relationship between quality management practices and corporate performance. On the other hand, much effort of companies on R&D strategy has significant moderate effect on the relationship between the two as well. Conclusion: Manufacturing and services companies in Korea need to make effort of quality management practices in order to improve corporate performance. Moreover, if that efforts are combined with customization strategy and R&D strategy, they will expect synergy effect on performance improvement.

• Journal of Families and Better Life
• /
• v.29 no.6
• /
• pp.55-69
• /
• 2011

The purpose of this study was to explore the effects of difficult temperament and mothers' reactions to child negative emotion on child emotion regulation strategies. Mothers of 253 preschoolers(Mage=4.04yrs.) responded to questionnaires on child temperament, mothers' reactions to child negative emotion, and child emotion regulation strategy. The results of regression analysis revealed that; 1) child difficult temperament positively predicted child's aggressive or outburst/appealing strategies whereas negatively predicted avoidance/none strategy; 2) child difficult temperament was not the variable predicting positive coping strategy, but mothers' emotion-focused or problem-focused reactions predicted child positive coping strategy whereas punitive or distress reactions predicted either aggressive or avoidance/none strategy; 3) child temperament moderated the link between mothers' reactions to child's negative emotion expression and child emotion regulation strategies. In particular, children with higher difficult temperament showed higher aggressive strategy under mothers' higher distress or punitive reaction and lower emotion focused or problem focused reaction. On the other hand, children with lower difficult temperament only showed avoidance/ none strategy when mothers showed higher minimization or punitive reaction. The results of current study underscore both child temperament, mothers' reactions and their interactions in predicting child emotion regulation strategies.