• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.67-72
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• 2006

Because computer system is complex gradually from fast growth of the Internet and sudden increase of Internet user and scale is growing, and dependence for computer system is rising gradually, data damage by mistake or disaster is big enough to can not imagine. Usually is continuous if wish to inform through internet and must update data stably, we should manage so that precious data is not erased from sudden problem through periodic backup. Plan to protect data safely for this should be readied. This paper proposes system that can make effective backup environment because consider environment and achievement method in these data management side. That is, implements system that achieve data backup and restore selectively in internet. Backup and restore about data had stored through browser even if disconnect directly to server because it is possible connect in internet by advantage of proposing system are available. Also, This system can manage data stored to server more efficiently by using selectively both backup and restore two methods.

• Journal of Climate Change Research
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• v.2 no.3
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• pp.143-159
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• 2011

Projects applying the CDM methodology AM0035 of the $SF_6$ Emission Reductions in Electrical Grids should provide direct monitoring of all the key parameters that are related to estimation of baseline and project emissions including detailed explanations of key operating conditions and procedures, and an explanation addressing uncertainty as the result of EB meeting 41. Through this study, recovery ratio during maintenance, purity of $SF_6$ before and after disposal, replacing, loss rate of $SF_6$ before and after reclamation, leakage emission from electricity consumption and fossil fuel combustion, considered conservatively the key parameter of various monitoring. Consequently, confirmed the reduction in the amount of reduction due to the baseline emission decrease, project emission increase.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.236-244
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• 2018

In this study, we tried to fabricate self - healing microcapsules using liquid inorganic materials which can be mixed directly with cement composites. The basic properties of the liquid inorganic material were evaluated and microencapsulation was performed. The focus of this paper is on the quality and manufacturing characteristics of cement composites rather than the healing effects of self - healing microcapsules according to mixed capsules. Test results, the self-healing microcapsules encapsulate liquid inorganic material which is stable at room temperature and has high crack followability, and the yield is over 90%. The size of self - healing microcapsule was able to change according to the synthetic agitation speed and it was able to secure more than 70% of target size. In addition, the loss of less than 10% was found to occur through the membrane strengthening of self - healing microcapsules, and it could be reduced by 50% compared with the case without membrane strengthening.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.326-332
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• 2019

Recently, the deep learning technology has gained lots of attention which leads to its application to various fields. Especially, there are recent attempts to overcome the limit of wireless communications systems through the use of the deep learning. In this paper, we have verified the performance of deep learning based transmit power control scheme. Unlike previous transmit power control schemes where the optimal transmit power is derived by solving the optimization problem explicitly, in the deep learning based transmit power control, the general solver for the optimization problem is derived through the deep neural network (DNN). Especially, by using the spectral efficiency as the loss function of DNN, the training can be performed without needing labels. Through simulation based on Tensorflow, we confirm that the transmit power control based on deep learning can achieve the optimal performance while reducing the computational complexity by 1/200.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.107-114
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• 2021

In this paper, a planar transistor oscillator for X-band using a newly proposed L-shaped monopole slot resonator is proposed. For planar design, an L-shaped monopole slot with an open-end is used as a resonator for a transistor oscillator. As a result of the simulated design of the resonator in three stages, a high Q value of 1169.84 and a high insertion loss of 49.934 dB were identified. The results of the final design and manufactured oscillator measurements confirmed that the oscillation output is greater than 7 dBm and has good phase noise characteristics of -58 dBc/Hz at 100 kHz offset. The proposed oscillator is planar and has the advantage of being directly applicable to microwave integrated circuit technology. It also has the advantage of being able to reduce its size as it can only be implemented in microstrip form without additional devices such as metal cavities and tuning screws in 3D structures, as in the case of a DRO (dielectric resonance oscillator).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1682-1687
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• 2020

We study the problem of sampling a subset of nodes of graphs for bandlimited graph signals such that the signal values on the sampled nodes provide the most information in order to reconstruct the original graph signal. Instead of directly minimizing the reconstruction error, we focus on minimizing the upper bound of the reconstruction error to reduce the complexity of the selection process. We further simplify the upper bound by applying useful approximations to propose a low-weight greedy selection process that is iteratively conducted to find a suboptimal sampling set. Through the extensive experiments for various graphs, we inspect the performance of the proposed algorithm by comparing with different sampling set selection methods and show that the proposed technique runs fast while preserving a competitive reconstruction performance, yielding a practical solution to real-time applications.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.17-25
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• 2021

When a person wears clothing, it is important to configure an outfit appropriate to the intended occasion. Therefore, T.P.O(Time, Place, Occasion) of the outfit is considered in various fashion recommendation systems based on artificial intelligence. However, there are few studies that directly infer the T.P.O from outfit images, as the nature of the problem causes multi-label and class imbalance problems, which makes model training challenging. Therefore, in this study, we propose a model that can infer the T.P.O of outfit images by employing a label-distribution-aware margin(LDAM) loss function. Datasets for the model training and evaluation were collected from fashion shopping malls. As a result of measuring performance, it was confirmed that the proposed model showed balanced performance in all T.P.O classes compared to baselines.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1195-1204
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• 2021

In this paper, we present an optimal design method for wave power generators using the response surface analysis. Especially, in our method, we reduce the mechanical loss by selecting the linear generator whose linear movement can be converted to the electrical energy directly with the vertical movement of waves. Therefore, we calculate the exciting force acting on the drive device in a slow-wave condition and determine the winding process with a ratio of the slots and poles for the improvement of energy conversion efficiency. In addition, we employ the regression analysis for deriving the shape factors of the stator and the translator, which have a significant effect on the performance of a generator. We choose the best design variables through the response surface analysis, and then we study the optimization method for designing the efficient experiment using the analysis results. Finally, we show the validity of the proposed method through the simulation results.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3
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• pp.165-173
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• 2009

The physical properties of a seafloor sediment have been used as a basic data for the ocean survey. Conventional methods such as a coring, a drilling, and a grabbing have been used to explore the physical properties but these methods have a number of shortcomings as it is time consuming, expensive and spatially limited. To overcome these limitations, seafloor sediment classification using acoustic signals has been studied actively. In this paper, we obtained the backscattered signal from the seafloor sediment using an echo sounder which is one kind of seafloor topography equipment. Nakagami probability density function of the backscattered signals from the seafloor sediment was computed and a Nakagami parameter was compared with the physical properties of the seafloor sediment. We have confirmed that Nakagami parameter, m is correlated with the physical properties of a seafloor sediment. This study will be utilized as a basic data of the seafloor sediment research.

• Journal of dental hygiene science
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• v.16 no.3
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• pp.225-234
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• 2016

The purpose of this study was to determine the oral health condition and behavioral status of Korean adults according to occupational status. The subjects were 7,676 adults, aged between 19 and 64 years, who completed both oral examination and questionnaire survey, among those who indicated that they were currently participating in economic activities, according to the data from the Fourth Korea National Health and Nutrition Examination Survey. Occupational class and employment status were selected as measures of occupational status. Complex-samples logistic regression models were used to assess the associations among oral health, behavioral, and occupational statuses. We found a significant occupational class-related difference in the oral health and behavioral statuses of both the men and women. In particular, the prevalence odds ratios of untreated dental caries in manual workers were 1.19 and 1.67 times higher than in non-manual workers, for men and women, respectively. As for oral health condition and behavioral status according to employment status, the health risk in temporary employment workers was higher than that in permanent employment workers. As for the prevalence odds ratios of the risk of dental caries, the highest values were observed for tooth brushing fewer than 3 times per day, not undergoing oral examinations, and chewing difficulty complaints. The risk of dental caries for agricultural, forestry, and fishing workers for both men and women was found to be the highest among other workers. Thus, strategies to promote workplace oral health in the microscopic and macroscopic perspectives should be developed to constantly monitor oral health problems, and to identify vulnerable social groups within occupational groups and the related factors that mediate oral health differences.