• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2338-2343
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• 2007

The practical studies on the method of particle contamination control for yield enhancement in the cleanroom were carried out. The method of the contamination control was proposed, which are composed of data collection, data analysis, improvement action, verification, and implement control. The partition check method for data collection and data analysis was used in the cellular phone module production lines. And this method was evaluated by the variation of yield loss between before and after improvement action. In case that the partition check method was applied, the critical process step was selected and yield loss reduction through improvement actions was observed. From these results, it is concluded that the partition check method is effective solution for particle contamination control in the cleanroom production lines.

• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.689-701
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• 2008

In this paper, a fully adaptive feedforward feedback synchronized tracking control approach is developed for precision tracking control of 6 degree of freedom (6DOF) Stewart Platform. The proposed controller is designed in decentralized form for implementation simplicity. Interconnections among different subsystems and gravity effect are eliminated by the feedforward control action. Feedback control action guarantees the stability of the system. The gains of the proposed controller can be updated on line without requiring any prior knowledge of Stewart Platform manipulator. Thus the control approach is claimed to be fully adaptive. By employing cross-coupling error technology, the proposed approach can guarantee both of position error and synchronization error converge to zero asymptotically. Because the actuators work in synchronous manner, the tracking performances are improved. The corresponding stability analysis is also presented in this paper. Finally, simulation is demonstrated to verify the effectiveness of the proposed approach.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.12
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• pp.51-58
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• 1993

This paper presents a design of the fuzzy decision maker which infers set value for fuel rate in the rotary kiln of making CaO. The fuzzy decision maker proposed are divided into two groups whose functions are different each other. The one operates when production demand is constant. The other deals with the status of varying production demand. We have chosen several variables used for composing condition and action part by investigating ingerent features of the rotary kiln and skilled operators`manual method of inferring fuel rate. Membership function of each variable was designed by analyzing experimental data and field data collected during two months. On-line operation with fuzzy rules suggested was done safely like human operators' action.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.28-32
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• 2007

In this paper, a unified regenerative inverter and control algorithm are proposed in order to perform regenerative action and active power filter action. While the regenerative mode of traction, it works as regenerative inverter to reduce a excessive power of DC bus line and the powering mode of the traction, it works as active power filter to compensate ac current distortion, power factor, and voltage unbalance. In the paper, a regeneration inverter used PWM DC/AC inverter algorithm. And an active power filter used p-q theory. We are carrying out a mode analysis of DC traction system similar to actual system with MG-set and experimenting with prototype model. Through the simulation and experiment, we were proving the regeneration inverter operation which suggested in this paper.

• International Journal of Railway
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• v.3 no.3
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.292.2-293
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• 2002

Pyrethroids are one of the most commonly used insecticides in worldwide. but it remains unclear whether pyrethroid compounds possess endocrine disrupting activity or not. T47D cells, an estrogen receptor positive human breast cancer cell line. is known to induce alkaline phosphatase (AlkP) only in response to progestins. Because the action of estrogen may be changed by the action of progestins (Kraus et al. 1995), it is important to examine the potential to produce progestin-mediated effects for determining endocrine disrupting activity of chemicals(LiLorenzo et al. 1991). (omitted)

• Journal of Biosystems Engineering
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• v.12 no.3
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• pp.42-49
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• 1987

The threshing action of the head-fed type threshing unit occurs mainly by the impact between threshing tooth and grains. It may be therefore the most fundamental step to calculate the time and order of the occurrance of impact by the tooth for predicting the performance of threshing unit. The threshing teeth arrangement was defined by length and diameter of threshing dram, number of spiral arrays, number of threshing teeth by kind per one spiral array, number of windings of spiral array around the threshing drum, delay angle of impact line. The linear equations for locus of left and right margin of paddy bundle, spiral array, impact line on the development figure of the threshing drum were expressed by fastors of the threshing teeth arrangement. In the computer program, the teeth which inflict impact were searched successively along the impact line. Searching range and impact condition were defined by the relation between four linear equations. If the impacting tooth was found, time and the kind of threshing tooth was derived from the coordinate of the threshing tooth. At this time the unit torque curve was accumulated on the array of computer memory. At last the completed torque curve of threshing drum shaft was described on the computer screen. Remarkably the peack valae and fluctuation of torque curve was decreased by adopting the delay angle of impact line.

• Journal of KIISE:Software and Applications
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• v.30 no.7_8
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• pp.672-680
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• 2003

A shopbot is a software agent whose goal is to maximize buyer´s satisfaction through automatically gathering the price and quality information of goods as well as the services from on-line sellers. In the response to shopbots´ activities, sellers on the Internet need the agents called pricebots that can help them maximize their own profits. In this paper we adopts Q-learning, one of the model-free reinforcement learning methods as a price-setting algorithm of pricebots. A Q-learned agent increases profitability and eliminates the cyclic price wars when compared with the agents using the myoptimal (myopically optimal) pricing strategy Q-teaming needs to select a sequence of state-action fairs for the convergence of Q-teaming. When the uniform random method in selecting state-action pairs is used, the number of accesses to the Q-tables to obtain the optimal Q-values is quite large. Therefore, it is not appropriate for universal on-line learning in a real world environment. This phenomenon occurs because the uniform random selection reflects the uncertainty of exploitation for the optimal policy. In this paper, we propose a Mixed Nonstationary Policy (MNP), which consists of both the auxiliary Markov process and the original Markov process. MNP tries to keep balance of exploration and exploitation in reinforcement learning. Our experiment results show that the Q-learning agent using MNP converges to the optimal Q-values about 2.6 time faster than the uniform random selection on the average.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1196-1203
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• 2004

Autonomous agents need considerable computational resources to perform rational decision-making. The complexity of decision-making becomes prohibitive when large number of agents are present and when decisions have to be made under time pressure. One of approaches in time-critical domains is to respond to an observed condition with a predefined action. Although such a system may be able to react very quickly to environmental conditions, predefined plans are of less value if a situation changes and re-planning is needed. In this paper we investigate strategies intended to tame the computational burden by using off-line computation in conjunction with on-line reasoning. We use performance profiles computed off-line and the notion of urgency (i.e., the value of time) computed on-line to choose the amount of information to be included during on-line deliberation. This method can adjust to various levels of real-time demands, but incurs some overhead associated with iterative deepening. We test our framework with experiments in a simulated anti-air defense domain. The experiments show that the off-line performance profiles and the on-line computation of urgency are effective in time-critical situations.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.121-131
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• 1997

This study was to design the clean room garment which fits for a body and adjusts well to the action. We examined the body's changes in action through a body measurment and made a sample of the clean room garment to which had adapted the body's changes in action and evaluated the function and the appearance compared with the existing the clean room garment. The followings were summery of the results : 1. Back intersyce breadth decreased, trunk length increased and the other parts were not change. At a posture of raising hands($M_3$) in comparison with an upright posture($M_0$). Back intersyce breadth, hip length and knee length increased and the other parts were a little change. At a bowing posture($M_2$) in comparison with an upright posture($M_0$). Back hip girth, knee length, hip length and leg length increased and the other parts were not change. At a working posture on a chair($M_1$) in comparison with an upright posture($M_0$). 2. The overall clean room garment was made increasing on the changes of part of a body through measuring and body measurement. 3. From the test of the function, it became known that the devised clean room garment was superior to the existing one in the parts of neck, shoulder, armpit and elbow at a working posture on a chair($M_1$), in the parts of neck, shoulder, and armpit at a bowing posture($M_2$), and the armpit at a posture of raising hands($M_3$). The appearance was better on the whole. 4. From the examination of photographs, the waist line of the devised clean room garment was not so much pulled up as that of the existing one on moving. And when sitting down on a chair, the waist line of the existing one was pulled down while that of the devised one had no change. As above, we investigated the actual conditions of wearing the clean room garment and measured the body's changes according the various actions. So we applied these results to the devised clean room garment but we couldn't research the clean mom effect of it owing to not obtaining the measuring instrument. The aspect of ergonomics liked the feeling of wearing and fitted to the action must be given consideration to the clean room garment, and simultaneously the dust-resistant effect must be taken into consideration in order to improve the quality of the goods. Therefore, we think it should be continued the research on the dust-resistant effect, material, washing method, quality control, and size along with the aspect of ergonomics.