• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.6
• /
• pp.979-986
• /
• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• Korean Journal of Artificial Intelligence
• /
• v.5 no.1
• /
• pp.29-37
• /
• 2017

The range of problems that can be handled by the activation of big data and the development of hardware has been rapidly expanded and machine learning such as deep learning has become a very versatile technology. In this paper, mnist data set is used as experimental data, and the Cross Entropy function is used as a loss model for evaluating the efficiency of machine learning, and the value of the loss function in the steepest descent method is We applied the Gradient Descent Optimize algorithm to minimize and updated weight and bias via backpropagation. In this way we analyze optimal reliability value corresponding to the number of exercises and optimal reliability value without overfitting. And comparing the overfitting time according to the number of data changes based on the number of training times, when the training frequency was 1110 times, we obtained the result of 92%, which is the optimal reliability value without overfitting.

• International Journal of Advanced Culture Technology
• /
• v.5 no.2
• /
• pp.82-89
• /
• 2017

The range of problems that can be handled by the activation of big data and the development of hardware has been rapidly expanded and machine learning such as deep learning has become a very versatile technology. In this paper, mnist data set is used as experimental data, and the Cross Entropy function is used as a loss model for evaluating the efficiency of machine learning, and the value of the loss function in the steepest descent method is We applied the GradientDescentOptimize algorithm to minimize and updated weight and bias via backpropagation. In this way we analyze optimal reliability value corresponding to the number of exercises and optimal reliability value without overfitting. And comparing the overfitting time according to the number of data changes based on the number of training times, when the training frequency was 1110 times, we obtained the result of 92%, which is the optimal reliability value without overfitting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.8
• /
• pp.761-767
• /
• 2011

In this paper, to improve performance of spectrum sensing, we propose the method which can find optimal threshold based on power of PU(Primary User) signal. To find optimal threshold value, we will use mathematical method, and find threshold which can has lowest error probability. Each SU(Secondary User) use this threshold and All Su makes local decision. All Su Send local decision to FC(Fusion Center). In this paper we consider K-out-of-n rule to combining local decision. To make global decision value, FC find optimal n. In the FC. FC received local decision which has lowest error probability and using optimal n and these vaule. FC make global decision value. In this paper, to analysis performance proposed scheme, we simulate proposed scheme using matlab and compare with traditional OR Rule. As a result of simulation, we can know that preposed scheme can get a better performance than traditional OR rule.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1164-1170
• /
• 2013

Since trees sequestrate carbon and reduce the level of its concentrations in the atmosphere, forests should be considered as carbon pools as well as timber producers. This study focuses on finding optimal harvest age when carbon sequestration from trees is accounted by forest managers. A dynamic programming employs a static volume matrix, and solves the harvest decision problems. If carbon value is accounted in a tree harvest decision model, the optimal harvest age increases. The harvest age of pine trees set by the government for national forests is longer than the optimal solution. It is possible to say that the managers of national forests put more values on the standing pine trees than the value of carbon sequestration. The regulation for private forests, on the other hand, ends up in a shorter harvest age than the optimal solution, and this discrepancy could lead to an inefficient private forest management.

• Journal of Internet of Things and Convergence
• /
• v.6 no.4
• /
• pp.15-19
• /
• 2020

In this paper, we propose a optimal CW(Conention Window) synchronization scheme in IEEE 802.11 WLANs. IEEE 802.11 WLANs support DCF(Distributed Coordination Function) mode for the MAC(Medium Access Control) operation. In DCF, the CW increases exponentially according to the collisions and becomes minimum CW according to the success of data transmissions. However, since the base minimum CW value is hardware or standard specific, the number of active stations and network status are not considered to determine the CW value. Even though the researches on optimal CW have beend conducted, they do not consider the optimal CW synchronization among mobile stations which occur network performance degradation. Therefore, this paper calculates the optimal CW value and shares it with mobile stations in the network.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.560-565
• /
• 1986

For the control of chemical process, optimal value of the process should be known at first. And process simulation is the previous step of optimal value calculation. However it is not a simple work to analyze chemical process system. Especially for the large scale chemical process system, many difficulties such as non-linearity and complexity caused by recycle streams should be overcome. In this paper, three strategies of large scale chemical process analysis were explained and discussed with case studies.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.2
• /
• pp.284-292
• /
• 2003

In this paper, we carried out the numerical examination of the initial value setting-up method to extend the range of optimal step parameter in a adaptive system which is controlled by LMS algorithm. For initial value setting-up methods, the general method which select the initial value randomly and the other method which applies the approximate value obtained from the direct method to initial value, were used. And then, we compared to the ranges of step parameter setting, the convergence speeds of mean-square-error, and the stabilities during the convergence process when the initial values were applied to the optimal directivity synthesis problem. According to the numerical simulation results, the initial value setting-up method by means of the direct method provides wider range for the step parameter, more efficient capability for convergence and stability, and more error correction ability than the general method.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.434-436
• /
• 1996

This paper investigates the optimal design of an electronic ballast of half bridge inverter type in consideration of the variation of ambient temperatures for a 15[W] triple-type compact fluorescent lamp. The performances of electronic ballasts under different values or the capacitance ratio in the resonant tank circuit are compared with each other in the practical temperature range between 15[$^{\circ}C$] and 35[$^{\circ}C$] to determine its optimum value. As a result, the optimum value is found to be such that $C_1/C_2=10$ at which value starting of the lamp is most stable and light output reaches its maximum value with lowest variation.

• Journal of Technology Innovation
• /
• v.16 no.1
• /
• pp.191-213
• /
• 2008

This study investigates the effect of technology import and R&D investment on the value of the firm in Korea. The result shows that the technology import announcement effect of firms with a low R&D investment is higher than that of firms with a high R&D investment. The evidence suggests that technology import can substitute the existing R&D capability of the firm. In addition, the result shows that there is an optimal level of technology import and R&D investment to maximize the value of the firm. In particular, firms with a low R&D investment and a large amount of technology import experience the highest announcement effect. The study concludes that an adequate allocation of fim's capital between R&D investment and technology import is needed for firm's optimal technology strategy.