• Journal of KIISE:Software and Applications
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• v.37 no.9
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• pp.694-705
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• 2010

The mutation operation is the main operation in the evolutionary programming which has been widely used for the optimization of real valued function. In general, the mutation operation utilizes both a probability distribution and its parameter to change values of variables, and the parameter itself is subject to its own mutation operation which requires other parameters. However, since the optimal values of the parameters entirely depend on a given problem, it is rather hard to find an optimal combination of values of parameters when there are many parameters in a problem. To solve this shortcoming at least partly, if not entirely, in this paper, we propose a new mutation operation in which the parameter for the variable mutation is theoretically estimated from the self-adaptive perspective. Since the proposed algorithm estimates the scale parameter of the Cauchy probability distribution for the mutation operation, it has an advantage in that it does not require another mutation operation for the scale parameter. The proposed algorithm was tested against the benchmarking problems. It turned out that, although the relative superiority of the proposed algorithm from the optimal value perspective depended on benchmarking problems, the proposed algorithm outperformed for all benchmarking problems from the perspective of the computational time.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.322-322
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• 2016

Phase change memory (PCM) has attracted much attention as one of the most promising candidates for next-generation nonvolatile memory. In that regard, the purposes of the study are to propose reference of effective pulse parameter to control phase switching operation and to invest the effect of nitrogen doped in PCM materials for improved cycling stability and economic energy consumption. Switching operation of PCM is affected by electric pulse parameter and as shown in figure.1 are composed to RT(rising time), ST(setting time), FT(falling time) and the effect of these parameter was precisely investigated. Transmission electron microscope (TEM) was used to confirm fine structure and retention cycle test was conducted to confirm reliability. Finally improvement reliability and economic power consumption in quantitatively are obtainable by optimum pulse parameter and nitrogen doping in GST material. these study is related to the engineering background of other semiconductor industries and it have confirmed to possibility further applications.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.839-849
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• 2023

The development of automation technology to reduce human error by minimizing human intervention is accelerating with artificial intelligence and big data processing technology, even in the nuclear field. Among nuclear power plant operation modes, the startup and shutdown operations are still performed manually and thus have the potential for human error. As part of the development of an autonomous operation system for startup operation, this paper proposes an action coordinating strategy to obtain the optimal actions. The lower level of the system consists of operating blocks that are created by analyzing the operation tasks to achieve local goals through soft actor-critic algorithms. However, when multiple agents try to perform conflicting actions, a method is needed to coordinate them, and for this, an action coordination strategy was developed in this work as the upper level of the system. Three quantification methods were compared and evaluated based on the future plant state predicted by plant parameter prediction models using long short-term memory networks. Results confirmed that the optimal action to satisfy the limiting conditions for operation can be selected by coordinating the action sets. It is expected that this methodology can be generalized through future research.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.22-28
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• 2006

Operation of a microturbine was simulated on the basis of component characteristic parameters obtained from performance test. Characteristic parameters, such as compressor and turbine efficiencies, recuperator effectiveness as well as turbine inlet temperature, were obtained for a wide operation range. Component characteristics including performance maps and characteristic curves were generated using measured data. Based on the component characteristics, a simulation program was constructed and operation of the microturbine was simulated, and the simulated results were compared with the measured data to verify the program. Also, influence of variation in the power control scheme on the operating characteristic and performance of the engine was simulated. The simulation program can be used for predicting operation of both healthy and degraded engine conditions.

• The Journal of Society for e-Business Studies
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• v.7 no.1
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• pp.107-127
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• 2002

Database system parameter tuning is one of database system tuning that achieve to improve performance of database system with application program tuning and data model tuning. By parameter tuning adjusts value of entry that is staled in data dictionary's parameter file that is included to database system, it is thing which make relevant database system can display performance of most suitable. And, it is that achievement is one o( possible tuning method immediately without occurrence of additional expense or involved hardware for database system performance elevation and ashes composition of software. But, it is actuality that administration about parameter practical use is not achieved, and is using Default Value of parameter that database management system offers just as it is systematically. So, this paper presents parameter tuning process that can ：achieve Parameter tuning of database system that is operating present systematically, and parameter tuning process each activity important input urea and tuning achievement product. And explain about effect and result that happen by sort database system performance and parameters that it is affinity systematically, and grasp relationships between parameter, and change parameter of string database system. And not that parameter uses contents that specify by fixing when establish database administration system, is going to emphasize and explain that must utilize changing continuously during database system operation. It changes parameter entry value how in various kinds different operation environment and present if must apply, and will arrange effect that this parameter enoy value alteration gets in performance liking into account point that is actuality that is using parameter that define database administrators when install the database system just as it is continually without alteration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.881-887
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• 2005

A total knee replacement is an extremely 'position-sensitive' operation; a malposition or a malalignment of the components will lead to a breakage of the component, a fracture around the knee prosthesis, and the limitation of range of the motion, etc. In a conventional total knee replacement, surgeons have to select an appropriate prosthesis according to the shape of the surgical region. A wrong selection may give rise to side effects or to need re-operation. Nevertheless, it is so difficult to choose the most proper prosthesis out of various kinds of prosthesis. This paper presents a surgical planning system for the total knee replacement with an operation simulating method in order to determine the parameters for the total knee replacement operation. We select an alignment axis and a resection angle as major operation parameters in the total knee replacement operation, and introduce the method to determine the major operation parameters with the operation simulator we developed. The simulator is used to determine operation parameters for optimized operations, to select the most appropriate prosthesis, and to analyze the prospective problems of the operation.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.1-6
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• 2014

PID(Proportional, Integral, Derivative) controller is one of the most used process controllers in nuclear power plants. The optimized parameter setting of process controller contributes to the stable operation and efficiency in the operating nuclear power plants. PID parameter setting is tuned when new process control system is established or process control system is changed. It is a burdensome work for I&C(Instrument and Control) engineers to tune the PID controller because it requires a lot of experience and knowledge. When the plant is in operation, inadequate PID parameter setting can be the cause of the unstable process of the plant. Therefore the results of PID parameter setting should be compared, simulated, verified and finally optimized. The practical PID tuning methods used in process controller are tuning operation calculation(Ziegler-Nicholes, Minimum TIAE, Lambda, IMC), exclusive tuning program based on computer and Matlab application. This paper introduces the various tuning methods and suggests an optimized PID tuning process in the operating nuclear power plants.

• Journal of the Ergonomics Society of Korea
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• v.7 no.2
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• pp.31-44
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• 1988

If an error occurs in the automatic mode when the advanced teleoperator system performs a task in hostile environment then the automatic mode changes into the manual mode. The operation by the control program and the operation by a human recover the error in the manual mode. The system resumes the automatic mode and continues the given task. It is necessary to improve the manual mode in order to make the best use of a man-robot system, as a part of the human interface technique. Therefore, the error recovery task is performed by combining the operation by the control program representing autonomy of a robot and the operation by a human representing versatility of a human operator effectively in the view point of human factors engineering. The geometric inverse kinematics is used for the calculation of the robot joint values in the operation by the control program. The singularity operation error and the parameter operation error often occur in this procedure. These two operation errors increase the movement time of the robot and the coordinate reading time, during the error recovery task. A singularity algorithm, parameter algorithm and fuzzy control are studied so as to remove the disadvantages of geometric inverse kinematics. And the geometric straight line motion is studied so as to improve the disadvantages of the operation by a human.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.69-74
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• 1998

In order to monitor the tool wear in milling operation, cutting force is measured as the tool wear increased. The digital signal processing methods are used to detect the tool wear . As AR parameter extract the feature of tool wear , it can be used as input parameter of pattern classifier. The FFT monitor the tool wear exactly , but it can not do real time signal processing. The band energy method can be used to real time monitoring of tool wear ,but int can degrade the exact monitoring.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.39.2-39
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• 2002

This paper presents adaptive add-on control algorithms for theconventional mode of operation of MEMS z-axis gyroscopes. This scheme is realized by adding an outer loop to a conventional force-balancing scheme that includes a parameter estimation algorithm. The parameter adaptation algorithm estimates the angular rate, identifies and compensates the quadrature error, and may permit on-line automatic mode tuning. The convergence and resolution analysis show that the proposed adaptive add-on control scheme prevents the angular rate estimate from being contaminated by the quadrature error, while keeping ideal resolution performance of a conventional force-balancing scheme.