• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.183-190
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• 2018

With decreasing the number of high school graduates, it is vital for each college to maintain its enrollment number as well as to preserve its dropout rate in a lower level. It is true that all universities and colleges have experienced inevitable dropouts that were in fact more serious in 2 to 3-year colleges. There have been prior studies to examine what factors affected to students' dropout in various ways. However, no specific programs were employed to mitigate the rates of dropout. In this study, new encouraging program is introduced for the students who were not ready to study and isolated from classroom. The result showed that the program led to the GPA enhancement in larger number of participants. Nevertheless, the sustainablity of the program would be unclear unless it combines with other existing programs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.18-24
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• 2010

A correct and accurate model of optical data storage systems is very important in development and performance evaluation of various data detection algorithms. In this paper, we present an nonlinear modeling scheme of a super-resolution near-field structure (Super-RENS) read-out signal using the canonical piecewise-linear (PWL) and the second-order Volterra models. Nonlinear equalizers may be developed on the basis of the information obtained from this nonlinear modeling. To mitigate the nonlinear inter-symbol interference (ISI), we proposed a new nonlinear equalizer for Super-RENS discs. Its validity is tested with the RF signal samples obtained from a Super-RENS disc. The experiment results verified the possibility that the canonical PWL and the second-older Volterra models can be utilized for nonlinear modeling of Super-RENS systems. The proposed equalizers are superior to the one without equalization in terms of bit error rate (BER).

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.9-17
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• 2014

Heterogeneous network (HetNet) is a network consisting of macrocells overlaid with small cells. In HetNet, the interference from macrocell to small cell users is a major cause of performance degradation of small cell users and enhanced inter-cell interference coordination (eICIC) is needed to mitigate the interference. Previous works on eICIC gives limited performance gain because these works focus on maximizing long-term throughput and rarely consider varying channel conditions over frames. This paper proposes a new algorithm which dynamically coordinates interference and schedules users on each frame to maximize the total utility of the network with lower computational complexity than exhaustive search. Simulation results show that the proposed algorithm achieves higher total throughput than the throughput with the conventional algorithm, and has higher fairness index than the conventional algorithm when there large number of users.

• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.79-90
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• 2017

Improving the urban environmental quality relies mainly on the increasing of urban forests capacity to store carbon dioxide. This study assesses the floristic diversity of urban institutional lands in Bukavu and their potential to reduce atmospheric $CO_2$. An exhaustive inventory over three sites ($Coll{\grave{e}}ge$ Alfajiri, $Cath{\acute{e}}drale$ Notre-Dame de la Paix and Institut $Sup{\acute{e}}rieur$ $P{\acute{e}}dagogique$) of Bukavu led to the identification of 1,113 trees of which the diameter at breast height (1.30 m) ranged from 4.9 to 161 cm. Results reveal a floristic diversity made up of 4 families of conifers with 4 species and 14 of broadleaves with 21 species. Average densities were of $54trees\;ha^{-1}$ and $5.21m^2\;ha^{-1}$ of basal area. Urban-based allometric equations used yielded up to 312.8 tons of carbon stored in trees aboveground biomass equivalent to 1,147.9 tons of $CO_2$ reduced from the atmosphere over the three sites. The rate of carbon storage reaches $15.1tons\;ha^{-1}$. Thus, trees of the three institutional sites in Bukavu play an important role in reducing atmospheric $CO_2$ and contribute, thereby, to mitigate global climate change effects. Given the current environmental challenge associated with high population growth rate in cities, the urban forest ecosystem in DRC requires to be extended and further investigation.

• The Journal of the Convergence on Culture Technology
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• v.2 no.4
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• pp.71-76
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• 2016

In this study, de-identification policies of the US, the UK, Japan, China and Korea are compared to suggest a future direction of de-identification regulations and a method for vitalizing the big data industry. Efficiently using the de-identification technology and the standard of adequacy evaluation contributes to using personal information for the industry to develop services and technology while not violating the right of private lives and avoiding the restrictions specified in the Personal Information Protection Act. As a counteraction, the re-identification issue may occur, for re-identifying each person as a de-identified data collection. From the perspective of business, it is necessary to mitigate schemes for discarding some regulations and using big data, and also necessary to strengthen security and refine regulations from the perspective of information security.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.13-20
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• 2003

Both MgO and $Sc_2O_3$ are shown to provide low interface state densities (in the $10^{11}{\;}eV^{-1}{\;}cm{\;}^{-2}$ range)on n-and p-GaN, making them useful for gate dielectrics for metal-oxide semiconductor(MOS) devices and also as surface passivation layers to mitigate current collapse in GaN/AlGaN high electron mobility transistors(HEMTs).Clear evidence of inversion has been demonstrated in gate-controlled MOS p-GaN diodes using both types of oxide. Charge pumping measurements on diodes undergoing a high temperature implant activation anneal show a total surface state density of $~3{\;}{\times}{\;}10^{12}{\;}cm^{-2}$. On HEMT structures, both oxides provide effective passivation of surface states and these devices show improved output power. The MgO/GaN structures are also found to be quite radiation-resistant, making them attractive for satellite and terrestrial communication systems requiring a high tolerance to high energy(40MeV) protons.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.119-128
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• 2014

This paper presents a new method for improving the quality of images corrupted by an external source that generates an attenuation and scattering of light like dust, water droplets and fog. Conventional defog methods typically encounter a distortion such that the restored image has low contrast and oversaturation of color in some regions because of the mis-estimated airlight and wrong media transmission. Therefore, in order to mitigate these problems, we propose a robust airlight selection method and local saturation evaluation method for estimating media transmission. The proposed method addresses the wrong media transmission and over-saturation problems caused by the mis-estimated airlight and thereby improves the restored image quality. The results of relevant experiments of the proposed method against conventional ones confirm the improved accuracy of atmospheric light estimation and the quality of restored images with regard to objective and subjective performance measures.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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• pp.363-375
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• 2015

Objective: This study aims to recognize the risk of current traffic systems and to investigate a method to decrease risk by doing exercise using an elastic-band and cognitive rehabilitation. Background: The existing traffic system usually focuses on the ordinary citizens, which may not be appropriate to the elderly. It may affect the cognition and walking speed of the elderly. This study tries to examine whether cognition and muscle training is appropriate to improve their vulnerability. Therefore this study will provide human ergonomics - based basic data in relation to the elderly to identify the risk of current signal system and to mitigate the risk. Method: A total of 30 elderly participants were divided into two groups: experimental and control groups. Experimental group (n=15) was trained to strengthen their muscles and to promote cognition, whereas control group (n=15) was not. The training was conducted twice a week for three weeks. To strengthen muscles, a yellow colored elastic-band was used, and a computer program for cognitive rehabilitation was used to develop cognition. In the experimental group, there were significant differences between pre and post exercises However, the control group didn't show any significant difference. The increase in cognition and walking speed was found in the experimental group, whereas there were no differences in the control group. Statistically there was no significant difference between the two groups. Results: The results of this study show that the exercise program using the elastic-band gave a positive effect on gait training thanks to the development of muscle power and balance. Conclusion: This study did not show any statistical difference or significant differences between the two groups, since time was restricted, we believe. Application: The results of the walking speed will help to prevent traffic collision.

• Spatial Information Research
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• v.17 no.2
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• pp.243-249
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• 2009

Damages from typhoon events have contributed more than 60 percent of total economic and social loss and the size of loss have been increased up to 800 million dollars per year in Korea, It is therefore necessary to make an effort to mitigate the loss of natural disasters. To facilitate the evaluation of damages in advance and to support the decision making to recover the damages, scientific methods have been adopted. With the effort, GIS data can provide various tools. Three components of hazard mapping are estimation of hazard, inventory for vulnerable features, and fragility of each feature. Vulnerability of natural disaster can be obtained by relation between loss and meteorological data such as precipitation and wind speed. Features can be categorized from other GIS data of public facilities and private properties, and then social and economic loss can be estimated. At this point, GIS data conversions for each model are required. In this study, we build a method to estimate typhoon risk based on GIS data such as DEM, land cover and land use map, facilities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.9
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• pp.707-721
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• 2018

In this paper, a small synthetic aperture radar(SAR) system with 30 cm resolution is proposed, and a RAW data-based Doppler parameter estimation and motion compensation algorithm is described in detail. Acquisition of both PolSAR and InSAR data are enabled because there are two channels each in the transmitter and receiver modules. Automotive-based field work is performed to obtain PolSAR data, and signal processing results are ultimately obtained. A motion compensation algorithm is used to mitigate the residual phase error due to platform oscillation, and improved performance is obtained with the motion compensation algorithm using the automotive field test data.