• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.51-56
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• 2016

To fabricate a copper (Cu)-based fine conductive filler having antioxidation property, submicron silver (Ag)-coated Cu particles were fabricated and their antioxidation property was evaluated. After synthesizing the Cu particles of $0.705{\mu}m$ in average diameter by a wet-reduction process, Ag-coated Cu particles were fabricated by successive Ag plating using ethylene grycol solvent. Main process parameters in the Ag plating were the concentration of reductant (ascorbic acid), the injection rate of Ag precursor solution, and the stirring rate in mixed solution. Thus, Ag plating characteristics and the formation of separate fine pure Ag phase were observed with different combinations of process parameters. As a result, formation of the separate pure Ag phase and aggregation between Ag-coated Cu particles could be suppressed by optimization of the process parameters. The Ag-coated Cu particles which were fabricated using optimal conditions showed slight aggregation, but excellent antioxidation property. For example, the particles indicated the weight gain not exceeding 0.1% until $225^{\circ}C$ when they were heated in air at the rate of $10^{\circ}C/min$ and no weight gain until 75 min when they were heated in air at $150^{\circ}C$.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.325-336
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• 2020

Nonlinear Invariant Attack is an attack that should be considered when constructing lightweight block ciphers with relatively simple key schedule. A shortcut to prove a block cipher's resistance against nonlinear invariant attack is checking the smallest dimension of linear layer-invariant linear subspace which contains all known differences between round keys is equal to the block size. In this paper, we presents the following results. We identify the structure and number of optimal bit-permutations which require only one known difference between round keys for a designer to show that the corresponding block cipher is resistant against nonlinear invariant attack. Moreover, we show that PRESENT-like block ciphers need at least two known differences between round keys by checking all PRESENT-like bit-permutations. Additionally, we verify that the variants of PRESENT-like bit-permutations requiring the only two known differences between round keys do not conflict with the resistance against differential attack by comparing the best differential trails. Finally, through the distribution of the invariant factors of all bit-permutations that maintain BOGI logic with GIFT S-box, GIFT-variant block ciphers require at least 8 known differences between round keys for the resistance.

• Environmental and Resource Economics Review
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• v.20 no.4
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• pp.859-882
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• 2011

Since two oil crises in the 1970s, Korea has actively engaged in overseas E&P projects to increase energy diversity as well as its self-development rate of energy resources. Korea's energy self-development rate, an index that indicates the ratio of resources acquired through overseas development compared to direct imports. Currently, Korea is conducting a total of 180 promising overseas oil development projects in 36 countries as of the end of 2010. By now, it has secured a reserve of around 1.63 billion barrels and production of around 176 thousand barrels of oil per day. The self-development rate for oil rose from 2.8% in 2006 to 7.4% in 2010. Not content with these remarkable successes, the korean government is planning to raise its self-development rate in oil to 25% by 2019, by promoting the active participation of Korean companies in overseas oil development projects. This paper is concerned with estimation of the required amount of government subsidies that includes loans and financial support through state-controlled banking institutions in order to reach the target 25% rate by 2019. The estimation results shows that government subsidies of at least 268 million dollars are needed for the current rate of 7.4% in oil. However, the amount sharply increases up to 1.25 billion dollars in 2019 when domestic oil demand rises to 1.02 billion barrels.

• Journal of Embryo Transfer
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• v.29 no.4
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• pp.333-337
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• 2014

To compensate for the critical shortage of human organs for allotransplantation, xenotransplantation studies using genetically modified pigs are being performed in Korea. Two types of pigs that are used are ${\alpha}1,3$-galactosyltransferase gene knockout (GalT KO) pigs and GalT KO+hCD46 (human complement regulatory protein) pigs. The present study measured the gestation time, birth weight, daily growth rate, and heart weight of both kinds of transgenic minipigs. The gestation period for both types of pigs was 117~119 days. There was no difference in the body weight of GalT KO (-/+) and GalT KO (-/-) piglets, but GalT KO+hCD46 ($-^{hCD46+}/+$) pigs were significantly heavier at birth than were GalT KO+hCD46 ($-^{hCD46+}/-^{hCD46+}$) pigs. During the first 10 weeks of life, the daily weight gain of GalT KO+hCD46 ($-^{hCD46+}/-^{CD46+}$) piglets, which are considered the optimal type for xenotransplantation, was 0.19 kg. The weight of hearts from GalT KO piglets up to two months of age was affected more by body weight than by age. Transgenic pigs showed no differences in gestation period or reproductive ability compared with normal pigs. These results comprise basic data that may be used in xenotransplantation studies and transgenic animal production in Korea.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.73-80
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• 2012

Recently, medical equipments are developed and used for diagnosis or studies. In addition, demand of techniques which automatically deal with three dimensional medical images obtained from the medical equipments is growing. One of the techniques is automatic bone segmentation which is expected to enhance the diagnosis efficiency of osteoporosis, fracture, and other bone diseases. Although various researches have been proposed to solve it, they are unable to be used in practice since a size of the medical data is large and there are many low contrast boundaries with other tissues. In this paper, we present a fast and accurate automatic framework for bone segmentation based on multi-resolutions. On a low resolution step, a position of the bone is roughly detected using constrained branch and mincut which find the optimal template from the training set. Then, the segmentation and the registration are iteratively conducted on the multiple resolutions. To evaluate the performance of the proposed method, we make an experiment with femur and tibia from 50 test knee magnetic resonance images using 100 training set. The proposed method outperformed the constrained branch and mincut in aspect of segmentation accuracy and implementation time.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.63-71
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• 2011

A large volume of uranium electrokinetic leachate has been generated during the electrokinetic decontamination to remove uranium from contaminated soil. The treatment technology for the reuse of the uranium leachate was developed. The concentration of uranium in the generated uranium leachate was 180 ppm and concentrations of Mg(II), K(I), Fe(II), and Al(III) ions ranged from 20 ppm to 1,210 ppm. The treatment process for uranium leachate consisted mainly of mixing and cohesion, precipitation, concentration, and filtration. In order to obtain the pH=11 of a precipitate solution, the calcium hydroxide needs to be 3.0g/100ml and the sodium hydroxide needed to be 2.7g/100ml. The results of several precipitation experiments showed that a mixture of NaOH+0.2g alum+0.15g magnetite was an optimal precipitant for filtration. The average particle size of precipitate with NaOH+alum+0.15g magnetite was $600\;{\mu}m$. Because the total value of metal concentrations in supernatant at pH=9 was the smallest, sodium hydroxide should be added with 0.2g alum and 0.15g magnetite for pH=9 of leachate.

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.596-608
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• 2004

A lot of work has been done to reduce disk access time in I/O intensive systems, which store and handle massive amount of data, by distributing data across multiple disks and accessing them in parallel. Most of the previous work has focused on an efficient mapping from a grid cell to a disk number on the assumption that data space is regular grid-like partitioned. Although we can achieve good performance for low-dimensional data by grid-like partitioning, its performance becomes degenerate as grows the dimension of data even with a good disk allocation scheme. This comes from the fact that they partition entire data space equally regardless of distribution ratio of data objects. Most of the data in high-dimensional space exist around the surface of space. For that reason, we propose a new declustering algorithm based on the partitioning scheme which partition data space from the surface. With an unbalanced partitioning scheme, several experimental results show that we can remarkably reduce the number of data blocks touched by a query as grows the dimension of data and a query size. In this paper, we propose disk allocation schemes based on the layout of the resultant data blocks after partitioning. To show the performance of the proposed algorithm, we have performed several experiments with different dimensional data and for a wide range of number of disks. Our proposed disk allocation method gives a performance within 10 additive disk accesses compared with strictly optimal allocation scheme. We compared our algorithm with Kronecker sequence based declustering algorithm, which is reported to be the best among the grid partition and mapping function based declustering algorithms. We can improve declustering performance up to 14 times as grows dimension of data.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.7
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• pp.159-172
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• 2016

This paper presents a novel algorithm for searching evacuation paths in indoor disaster environments. The proposed method significantly improves the time complexity to find the paths to the evacuation exit by introducing a light-weight Disaster Evacuation Graph (DEG) for a building in terms of the size of the graph. With the DEG, the method also considers load balancing and bottleneck capacity of the paths to the evacuation exit simultaneously. The behavior of the algorithm consists of two phases: horizontal tiering (HT) and vertical tiering (VT). The HT phase finds a possible optimal path from anywhere of a specific floor to the evacuation stairs of the floor. Thus, after finishing the HT phases of all floors in parallel the VT phase begins to integrate all results from the previous HT phases to determine a evacuation path from anywhere of a floor to the safety zone of the building that could be the entrance or the roof of the building. It should be noted that the path produced by the algorithm. And, in order to define the range of graph to process, tiering scheme is used. In order to test the performance of the method, computing times and evacuation times are compared to the existing path searching algorithms. The result shows the proposed method is better than the existing algorithms in terms of the computing time and evacuation time. It is useful in a large-scale building to find the evacuation routes for evacuees quickly.

• Resources Recycling
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• v.13 no.2
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• pp.39-46
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• 2004

The amount of electric furnace dust has been steadily increasing due to the increase of iron scraps which are usually recycled by electric furnace melting process. To date, this electric furnace dust has usually been treated by landfilling, however, because of shortage of landfill sites and heavy metal leaching more desirable treatment schemes are urgently needed. Among several possible schemes for the proper treatment of electric furnace dust, its recycling can be said to be most desirable. In present study, the triboelectrostatic separation of zinc and zinc-containing components from electric furnace dust was attempted based on its physicochemical properties such as particle shape, size distribution, and chemical assay. The dust was found to be mixed with spherical and non-spherical shaped particles and its major component materials were $ZnFe_2$$O_4$, ZnO, Fe, Zn, and FeO. The content of zinc-containing components in the entire dust was observed to be in the range of 15～30 wt%, which reasonably justified that zinc is recyclable. The triboelectrostatic characteristic of each component material was found to be different each other since their work functions were different, and based on this characteristic zinc and zinc-containing component could be flirty separated from the dust. After selecting a proper tribo-elec-trification material, the separation features of zinc and zinc-containing component were examined by taking the distance of electrodes, electric field strength, and scavenging as the experimental variables. The highest zinc-content obtained under the optimal separating condition was found to be up to 50wt%.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.152-159
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• 2010

The influence of urushiol, as an allergen on laccase property of Fomitella fraxinea was investigated. The enzyme production was reached to the highest level after 10 days, cultivation and the activity and mycelial biomass were increased by 2.5 and 1.5 folds, respectively, by adding urushiol in the culture medium. In liquid cultures using a Cu Mn-free medium, laccase lactivity was decreased by 3.8-9.2 folds, with similar dry cell weight. Two isoenzymes, were purified using anion exchange, hydrophobic interaction and size-exclusion chromatographies. Both isoenzymes are monomeric proteins, with $M_W$ around 67 kDa(Lac1) and 66 kDa(Lac2), and isoelectric points of 3.67 and 3.81. The optimal conditions for purified isoenzymes were found to be pH 4.5-5.0 and $30-35^{\circ}C$. Activity decreased by the addition of $Fe^{2+}$, $Mg^{2+}$, $Na^+$, and strongly inhibited by EDTA and sodium azide.