• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.65-65
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• 2011

We report the application of conducting metal oxide electrodes for semiconducting metal oxide gas sensors. Pt interdigitated electrodes have been commonly used for metal oxide gas sensor because of the low resistivity, excellent thermal and chemical stability of Pt. However, the high cost of Pt is an obstacle for the wide use of metal oxide gas sensors compared with its counterpart electrochemical gas sensors. Meanwhile, relatively low-cost conducting metal oxides are widely being used for light-emitting diodes, flat panel displays, solar cell and etc. In this work, we have fabricated $WO_3$ and $SnO_2$ thin film gas sensors using interdigitated electrodes of conducting metal oxides. Thin film gas sensors based on conducting metal oxides exhibited superior gas sensing properties than those using Pt interdigitated electrodes. The result was attributed to the low contact resistance between the conducting metal oxide and the sensing material. Consequently, we demonstrated the feasibility of conducting metal oxide interdigitated electrodes for novel gas sensors.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.4
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• pp.217-226
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• 2014

Since the world has changed to a society of 21st century high-tech industries, the modern people have become reluctant to work in a difficult and dirty environment. Therefore, unmanned technologies through robots are being demanded. Now days, effects such as voice, control, obstacle avoidance are being suggested, and especially, voice recognition technique that enables convenient interaction between human and machines is very important. In this study, in order to conduct study on the stable motion control of the robot system that has mobile-manipulator structure and is voice command-based, kinetic interpretation and dynamic modeling of two-armed manipulator and three-wheel mobile robot were conducted. In addition, autonomous driving of three-wheel mobile robot and motion control system of two-armed manipulator were designed, and combined robot control through voice command was conducted. For the performance experiment method, driving control and simulation mock experiment of manipulator that has two-armed structure was conducted, and for experiment of combined robot motion control which is voice command-based, through driving control, motion control of two-armed manipulator, and combined control based on voice command, experiment on stable motion control of voice command-based robot system that has mobile-manipulator structure was verified.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.9
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• pp.831-835
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• 2000

The uniformity of themperature on a wafer is a wafer is one the most important parameters to conterol the RTF(Rapid Thermal Process) with proper input signals. It is impossible to achieve the uniformity of temperature without the exact estimation of temperature ar all points on the wafer. There fore, it is difficult to understand the internal dynamics as well as the structural complexities of the RTP, which is aprimary obstacle to measure the distributed temperatures on the wafer accurately. Furthermore, it is also hard to accomplish desirable estimation because only a few pyrometers are available in the general equipments. In the paper, a thermal model based on the chamber grometry of the AST SHS200 RTP system is developed to effectively control the thermal uniformity on the wafer. First of all, the estimation method of one-point measurement is developed, which is properly extended to the case of multi-point measurements. This thermal model is validated through simulation and experiments. The proposed work can be utilized to building a run-by -run or a real-time control of the RTP.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.946-951
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• 2009

The small multi-jointed robots for most education are developed with the way of firmware. But the firmware may be very difficult to develop as gradually increasing throughputs and control routines. Due to limit of firmware we try to use on RTOS, but hard to adapt on the small multi-jointed robots. It would be hard to install RTOS into the small multi-jointed robots because of the size capacity of RTOS, and lack of libraries for control of the particular hardware. Moreover, even its RTOS with many functions causes its to make overheads scheduling, TCB (Task Control Block), and task states. Also to keep maintenance of RTOS, it is composed of components for the whole structure of my proposed RTOS. Additionally, We provided with libraries of servo motor and sensor control and developed RMS (Rate Montonic scheduler) to handle tasks on real time and reduce overheads. Therefore, It is possible to work the fixed priority and task preemptive way. We show one example of the multi-jointed robot installed with my proposed RTOS, which shows to obstacle avoidance and climbing up the slope.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.2
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• pp.62-67
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• 2000

The uniformity of temperature on a wafer is one of the most important parameters to control the RTP (Rapid Thermal Process) with proper input signals. Since it is impossible to achieve the uniformity of temperature without exact estimation of temperature at all points on the wafer, the difficulty of understanding internal dynamics and structural complexities of the RTP is a primary obstacle to accurately measure the distributed temperatures on the wafer. Furthermore, it is also hard to accomplish desirable estimation because only few pyrometers have been commonly available in the general equipments. In the paper, a thermal model based on the chamber geometry of the AST SHS200 RTP system is developed to effectively control the thermal uniformity on the wafer. First of all, the estimation method of one-point measurement is developed, which is properly extended to the case of multi-point measurements. This thermal model is validated through certain simulation and experiments. The work can be usefully contributed to building a run-by-run or a real-time controls of the RTP.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.397-403
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• 2016

Various walking robot platforms have been developed to carry out missions such as explorations, pass of obstacle or inspections of dangerous environments. In this work, a four legs mechanism based on Jansen mechanism is developed, which can follow a certain track and overcome obstacles. To find the ideal locus, computer programs are used such as M. sketch and Working model. Using these program tools, moderate linkage sizes are selected in Science Box. Furthermore, in order to optimize design of legs, a level average analysis is used as well as Edison S/W. Through the design optimization, improved stride of locus is found.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.26-28
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• 2005

Induction generator is the most common generator in wind energy systems because of its simplicity, ruggedness, little maintenance, price and etc. But the main drawbacks in induction generator is its need of reactive power means to build up the terminal voltage. This drawback is not an obstacle today where PWM inverters can accurately supplies the induction generator with its need from reactive power. For a insurance of three-phase induction generator requires capacitive reactance of the terminal. Most of previous work uses numerical iterative method to determine this minimum capacitor. But the numerical iteration takes long time and divergence may be occurs. In this paper is presented the design methods of the minimum self-excited capacitor required for induction generator operation. And a new formula from the equivalent circuit for stable generation operation of self-excited induction generator calculates the proper capacity to obtain the terminal voltage of the load stage. The validity of proposed design methods is confirmed by experimental and computed results.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1726-1735
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• 2008

Seoulmetro has operated the air cooling equipment for 57 stations to improve services focused on our customers who use Seoulmetro during the summer season and has established every year. However, a new set of problems has arisen with the cooling tower to support a heat exchange of cooling water. The most important matter is loss of efficiency in the cooling tower. The leading cause of this problem is that we use an indoor type. As the cooling tower room is located in the underground of the city because of the residents near the station. Therefore It is difficult to establish the cooling tower on the ground. But it is unsuitable for the location requirements of the underground type because it has a limited space to set up the air cooling equipment, for example, the cooling tower and a ventilating opening. As a result of such an unfavorable condition, the cooling tower doesn't work efficiently and the warmth of cooling water because of insufficiency of a heat exchange and a refrigerator's technical obstacle such as a high-temperature and a high-pressure has arisen. To prevent this situation, the operator tend to reduce refrigerant. Accordingly, the efficiency of the air conditioning is getting lower and lower. Study wishes to analyze the matter to improve indoor cooling tower efficiency and recommend a best practice for a person who manage the establishment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.80-87
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• 2021

Our study introduces an improved modular agricultural platform to provide convenience to agricultural workers. We upgrade the platform design in three parts, namely, by adding a 458 pattern tire, electricity control, and four-wheel steering function, to improve the platform performance. Results showed that the upgrades enhanced the platform performance and reduced its overall weight as compared with the existing platform. To demonstrate the performance of our improved platform, we conducted five types of experiments with respect to the climbing angle, variable width, attitude control, speed, and obstacle passing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3120-3137
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• 2021

Small-sized IoT wireless sensing devices can be deployed with small aircraft such as drones, and the deployment of mobile IoT devices can be relocated to suit data collection with efficient relocation algorithms. However, the terrain may not be able to predict its shape. Mobile IoT devices suitable for these terrains are hopping devices that can move with jumps. So far, most hopping sensor relocation studies have made the unrealistic assumption that all hopping devices know the overall state of the entire network and each device's current state. Recent work has proposed the most realistic distributed network environment-based relocation algorithms that do not require sharing all information simultaneously. However, since the shortest path-based algorithm performs communication and movement requests with terminals, it is not suitable for an area where the distribution of obstacles is uneven. The proposed scheme applies a simple Monte Carlo method based on relay nodes selection random variables that reflect the obstacle distribution's characteristics to choose the best relay node as reinforcement learning, not specific relay nodes. Using the relay node selection random variable could significantly reduce the generation of additional messages that occur to select the shortest path. This paper's additional contribution is that the world's first distributed environment-based relocation protocol is proposed reflecting real-world physical devices' characteristics through the OMNeT++ simulator. We also reconstruct the three days-long disaster environment, and performance evaluation has been performed by applying the proposed protocol to the simulated real-world environment.