• Economic and Environmental Geology
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• v.49 no.4
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• pp.269-280
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• 2016

I presented three vector crustal magnetic anomaly components and six gradients by using spherical Slepian functions over the cap area of $20^{\circ}$ of radius centered on the South Pole. The Swarm mission, launched by European Space Agency(ESA) in November of 2013, was planned to put three satellites into the low-Earth orbits, two in parallel in East-West direction and one in cross-over of the higher altitude. This orbit configuration will make the gradient measurements possible in North-South direction, vertical direction, as well as E-W direction. The gravity satellites, such as GRACE and GOCE, have already implemented their gradient measurements for recovering the accurate gravity of the Earth and its temporal variation due to mass changes on the subsurface. However, the magnetic gradients have little been applied since Swarm launched. A localized magnetic modeling method is useful in taking an account for a region where data availability was limited or of interest was special. In particular, computation to get the localized solutions is much more efficient and it has an advantage of presenting high frequency anomaly features with numbers of solutions fewer than the global ones. Besides, these localized basis functions that were done by a linear transformation of the spherical harmonic functions, are orthogonal so that they can be used for power spectrum analysis by transforming the global spherical harmonic coefficients. I anticipate in scientific and technical progress in the localized modeling with the gradient measurements from Swarm and here will do discussion on the results of the localized solution to represent the three vector and six gradient anomalies over the Antarctic area from the synthetic data derived from a global solution of the spherical harmonics for the crustal magnetic anomalies of Swarm measurements.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.435-444
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• 2009

In situ stabilization of heavy metals through adsorption onto indigenous bacterial biofilm developed on soil particles was investigated. Biofilms were developed in soil columns by supply of various carbon sources such as acetate, lactate and glucose. During development of biofilms, acetate, lactate, and glucose solutions were flew out from the soil columns with volume ratios of 98.5%, 97.3%, and 94.7%, respectively, when compared with soil column supplied with deionized water. Decrease in effluent amounts through the soil columns amended with carbon sources over time indicated the formation of biofilms resulting in decrease of soil porosity. Solutions of Cd, Cr(VI), Cu, Pb, and Zn were injected into the biofilms supported on soil particles in the columns, and the dissolved heavy metals in effluents were determined. Concentrations of dissolved Cd, Cr(VI), Cu, and Zn in the effluents through biofilm columns were lower than those of control column supplied with deionized water. The result was likely due to enhanced adsorption of the metals onto biofilms. Efficiency of metal removal by biofilms depended on the type of carbon sources supplied. The enhanced removal of dissolved heavy metals by bacterial biofilms in this study may be effectively applied to technical development of in situ stabilization of heavy metals in natural soil formation contaminated with heavy metals.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.231-237
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• 2005

The sizes and structure of micelles and vesicles formed in ammonium dodecyl sulfate (ADS)/octadecyl trimethyl ammonium chloride (OTAC) mixed aqueous solutions were analyzed by small-angle neutron scattering. In micellar regions of pure ADS and OTAC aqueous solution, the spherical micelles were formed at given concentrations and their sizes were 40 and $61{\AA}$, respectively. The structure transition of pure micelles occurred above 300 mM due to the constancy of the intermicellar distance above 250 mM. The coexisting region of mixed micelles and vesicles in phase diagram of mixed system was also assured. It was investigated that vesicle formed spontaneously took a bilayer structure. The lamellar thickness of vesicles decreased with increasing concentration of vesicle samples. However, the size could not be determined for mixed micelle and vesicle above 100 nm due to limitation of low q ranges. Finally, The 9 mM solution of ADS mole fraction 0.9 (${\alpha}$=0.9) showed bilayer structure compared to phase diagram classified into mixed micelle.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.4
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• pp.159-172
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• 2023

In general, social problem-solving research aims to create important social value by offering meaningful answers to various social pending issues using scientific technologies. Not surprisingly, however, although numerous and extensive research attempts have been made to alleviate the social problems and issues in nation-wide, we still have many important social challenges and works to be done. In order to facilitate the entire process of the social problem-solving research and maximize its efficacy, it is vital to clearly identify and grasp the important and pressing problems to be focused upon. It is understandable for the problem discovery step to be drastically improved if current social issues can be automatically identified from existing R&D resources such as technical reports and articles. This paper introduces a comprehensive dataset which is essential to build a machine learning model for automatically detecting the social problems and solutions in various national research reports. Initially, we collected a total of 700 research reports regarding social problems and issues. Through intensive annotation process, we built totally 24,022 sentences each of which possesses its own category or label closely related to social problem-solving such as problems, purposes, solutions, effects and so on. Furthermore, we implemented four sentence classification models based on various neural language models and conducted a series of performance experiments using our dataset. As a result of the experiment, the model fine-tuned to the KLUE-BERT pre-trained language model showed the best performance with an accuracy of 75.853% and an F1 score of 63.503%.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.56-66
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• 2022

Due to the recent increase in information encountered on social media, algorithm-based recommendation formats selectively provide information based on user information, which often causes a filter bubble effect by an Echo Chamber. Eco-chamber refers to a phenomenon in which beliefs are amplified or strengthened by communication only in an enclosed system, and filter bubbles refer to a phenomenon in which information providers provide customized information according to users' interests, and users encounter only filtered information. The purpose of this study is to propose a method of efficiently selecting information as a way to improve the filter bubble phenomenon by such an echo chamber. The research progress method analyzed recommended algorithms used on YouTube, Facebook and Amazon. In this study, humanities solutions such as training critical thinking skills of social media users and strengthening objective ethical standards according to self-preservation laws, and technical solutions of model-based cooperative filtering or cross-recommendation methods were presented. As a result, recommended algorithms should continue to supplement technology and develop new techniques, and humanities should make efforts to overcome cognitive dissonance and prevent users from falling into confirmation bias through critical thinking training and political communication education.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.1
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• pp.24-34
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• 2015

Domestic companies supplying electricity must increase obligatory duty to use renewable energy annually. If not met with obligatory allotment, the electricity-supply companies must pay RPS (Renewable Portfolio Standards) penalty. Although the power plants using a pulverizing coal firing boiler could co-fire up to around 3 per cent with wood pellets mixed in with coal feedstock without any major equipment revamps, they recorded only about 60 per cent fulfillment of RPS. Consequently, USD 46 million of RPS penalty was imposed on the six power supplying subsidiaries of GENCOs in 2014. One of the solutions to reduce the RPS penalty is that the power supply companies adopt the co-firing of torrefied lignocellulosic biomass in coal plants, which may contribute to the use of over 30 per cent of torrefied biomass mixed with bituminous coals. Extra binder was required to form pellets using torrefied biomass such as wood chips, PKS (Palm Kernel Shell) and EFB (Empty Fruit Bunch). Instead of corn starch, 30, 50 and 70 per cent of Larix saw dusts were respectively added to the torrefied feedstocks such as Pinus densiflora chips, PKS and EFB. The addition of saw dusts led to the decrease of the calorific values of the pellets but the forming ability of the pelletizer was exceedingly improved. Another advantage from the addition of saw dusts stemmed from the reduction of ash contents of the pellets. Finally, it was confirmed that torrefied oil palm biomass such as PKS and EFB could be valuable feedstocks in making pellets through improved binding ability.

• KIISE Transactions on Computing Practices
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• v.22 no.6
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• pp.284-289
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• 2016

In the Hadoop-based Big Data analysis model, the data movement between the legacy system and the analysis system is difficult to avoid. To overcome this problem, a unified Big Data file system is introduced so that a unified platform can support the legacy service as well as the analysis service. However, major challenges in avoiding the performance degradation problem due to the interference of two services remain. In order to solve this problem, we first performed a real-life simulation and observed resource utilization, workload characteristics and I/O balanced level. Based on this analysis, two solutions were proposed both for the system level and for the technical level. In the system level, we divide I/O path into the legacy I/O path and the analysis I/O path. In the technical level, we introduce an aggressive prefetch method for analysis service which requires the sequential read. Also, we introduce experimental results that shows the outstanding performance gain comparing the previous system.

• The Journal of Korean Association of Computer Education
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• v.17 no.6
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• pp.93-102
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• 2014

A mobile office environment using mobile devices, such as tablet PC, mobile phone is gradually increased in enterprises, banking and public institutions etc which is no limitation on places. It occurs advanced and persist security threats that are required effective security management policy and technical solution to be secure. For BYOD (Bring Your Own Device) environment, technical security management solutions of network control based, MDM (Mobile Device Management), MAM (Mobile Application Management), MCM (Mobile Contents Management) were released, evolved and mixed used. In perspective of integrated security management solution, mobile security product should be selected to consider user experience and environment and correct quality evaluation model of product is needed which is provided standards and guidance on the selection criteria when it was introduced. In this paper, the most widely used MDM solution is selected to take a look at its features and it was reviewed the product attributes with related international standard ISO/IEC25010 software quality attributes. And then it was derived evaluation elements and calculated the related metrics based on the quality analysis model. For the verification of quality evaluation model, security checks list and testing procedures were established; it applied metrics and analyzed the testing result through scenario based case study.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.1
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• pp.36-42
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• 1997

The fiber wall filling(FWF) technology, which is based on Precipitatin of fillers in the micropores of the cell wall structure of never-dried chemical pulp fiber, has been developed to improve filling and loading process in papermaking. In presenting FWF technique here, micropores of pulp fiber are first impregnated with an ionic solution of water soluble salt and consecutively impregnated with the second salt solution. This procedure generates an insoluble precipitate within the micropores of cell wall by chemical interaction of these two ionic salt solutions This is the first attempts to use FWF technology for the quality of waste paper grade which is recycled in papermaking, even though this FWF technology has been impressively improved for never-dried chemical pulp in filling and loading process of papermaking. The precipitated amount of CaCO$_3$ and SrCO$_3$ reached 5-6% and 4-5% of the waste paper weight respectively, which was measured by ash content of the burned waste paper fiber. On the other way the precipitated amounts of those materials impregnated into never-dried chemical pulp fiber have reached 17-18% and 16-18% respectively. The micropore loading technique gives optical and physical properties to the handsheets formed with celt-wall-filled fibers which are better than those handsheet properties resulting from conventional loading. The papers made from the cell-wall-filled pulps are stronger than those with the customary location of filler between the fibers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.167-177
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• 2011

Renewable energy resources and technologies have the potential to provide long-lasting solutions of the global energy-requirements faced by the economic and environmental sectors of a nation. Therefore, waste money bills were used as renewable energy source for the production of bio-ethanol. In this study, different concentrated NaOH 0.5%. 1.0%, 2.0%, 3.0% and 0.0% (as a control) were used for 10, 20 and 30 mins at $121^{\circ}C$/15 psi in an autoclave. Saccharification and fermentation (aerobic and anaerobic) were carried out through commercial enzyme Celluclast 1.5 L, Novozymes 188 and Saccharomyces cerevisiae KCCM 11304 respectively. The results of pretreatment showed that the NaOH pre-treated substrate enhanced enzyme action and released more amount of glucose. The amount of glucose was found with the increasing concentration of NaOH and time $44996.95{\pm}6.30$, $46763.10{\pm}3.56$, $53421.32{\pm}4.72$, $63431.25{\pm}6.95$ and $56850.98{\pm}6.75\;ng/{\mu}l$ for 30 min respectively. As for bioethanol, the conversion rate of NaOH resulted $1010.08{\pm}4.71$, $1050.25{\pm}4.37$, $1109.49{\pm}4.39$, $1139.25{\pm}3.26$ and $1020.77{\pm}3.89$ ppm for aerobic; $16730.54{\pm}6.67$, $17076.45{\pm}6.25$, $17516.17{\pm}4.49$, $19782.68{\pm}6.19$ and $17973.39{\pm}7.50$ ppm for anaerobic and $18935.02{\pm}4.59$, $19895.45{\pm}5.39$, $21912.95{\pm}4.83$, $24895.21{\pm}6.72$ and $18961.21{\pm}4.90$ ppm for anaerobic condition with benzoic acid for respective condition. Thus, the results of the present work clearly revealed that with the increasing of alkali concentration might be more effective for bio-ethanol production from waste money bill, which is economic and environmental friendly.