• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.122-122
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• 2008

Recently, Metal/Alumina/Silicon-Nitride/Silicon-Oxide/Silicon (MANOS) structures are one of the most attractive candidates to realize vertical scaling of high-density NAND flash memory [1]. However, as ANO layers are miniaturized, negative and positive bias temperature instability (NBTI/PBTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density increase, ${\Delta}D_{it}$, the gate leakage current, ${\Delta}I_G$. and the retention characteristics, in MONOS capacitors, becomes an important issue in terms of reliability. It is well known that tunnel oxide degradation is a result of the oxide and interfacial traps generation during FN (Fowler-Nordheim) stress [2]. Because the bias temperature stress causes an increase of both interfacial-traps and fixed oxide charge could be a factor, witch can degrade device reliability during the program and erase operation. However, few studies on NBTI/PBTI have been conducted on improving the reliability of MONOS devices. In this work, we investigate the effect of post-annealing gas on bias temperature instability (BTI), such as the flat band voltage shift, ${\Delta}V_{FB}$, the interfacial trap density shift, ${\Delta}I_G$ retention characteristics, and the gate leakage current characteristics of MANOS capacitors. MANOS samples annealed at $950^{\circ}C$ for 30 s by a rapid thermal process were treated via additional annealing in a furnace, using annealing gases $N_2$ and $N_2-H_2$ (2 % hydrogen and 98 % nitrogen mixture gases) at $450^{\circ}C$ for 30 min. MANOS samples annealed in $N_2-H_2$ ambient had the lowest flat band voltage shift, ${\Delta}V_{FB}$ = 1.09/0.63 V at the program/erase state, and the good retention characteristics, 123/84 mV/decade at the program/erase state more than the sample annealed at $N_2$ ambient.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.7
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• pp.48-56
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• 2011

Recently, new storage device SSD(Solid State Disk) based on NAND flash memory is gradually replacing HDD(Hard Disk Drive) in mobile device and thus a variety of research efforts are going on to find the cost-effective ways of performance improvement. By increasing the NAND flash channels in order to enhance the bandwidth through parallel processing, DRAM buffer which acts as a buffer cache between host(PC) and NAND flash has become the bottleneck point. To resolve this problem, this paper proposes an efficient low-cost scheme to increase SSD performance by improving DRAM buffer bandwidth through scheduling techniques which utilize DRAM multi-banks. When both host and NAND flash multi-channels request access to DRAM buffer concurrently, the proposed technique checks their destination and then schedules appropriately considering properties of DRAMs. It can reduce overheads of bank active time and row latency significantly and thus optimizes DRAM buffer bandwidth utilization. The result reveals that the proposed technique improves the SSD performance by 47.4% in read and 47.7% in write operation respectively compared to conventional methods with negligible changes and increases in the hardware.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.54-62
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• 2015

Although NAND flash-based SSD (Solid-State Drive) provides superior performance in comparison to HDD (Hard Disk Drive), it has a major drawback in write endurance. As a result, the lifetime of SSD is determined by the workload and thus it becomes a big challenge in current technology trend of such as the shifting from SLC (Single Level Cell) to MLC (Multi Level cell) and even TLC (Triple Level Cell). Most previous studies have dealt with wear-leveling or improving SSD lifetime regarding hardware architecture. In this paper, we propose the optimal configuration of host I/O stack focusing on file system, I/O scheduler, and link power management using JEDEC enterprise workloads in terms of WAF (Write Amplification Factor) which represents the efficiency perspective of SSD life time especially for host write processing into flash memory. Experimental analysis shows that the optimum configuration of I/O stack for the perspective of SSD lifetime is MinPower-Dead-XFS which prolongs the lifetime of SSD approximately 2.6 times in comparison with MaxPower-Cfq-Ext4, the best performance combination. Though the performance was reduced by 13%, this contributions demonstrates a considerable aspect of SSD lifetime in relation to I/O stack optimization.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.49-55
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• 2007

To improved the multi-resolution fast hierarchical motion estimation by using de-interlacing algorithm that is effective in term of both performance and VLSI implementation, is proposed so as to cover large search area field-based as well as frame based image processing in SoC design. In this paper, we have simulated a various picture mode M=2 or M=3. As a results, the proposed algorithm achieved the motion estimation performance PSNR compare with the full search block matching algorithm, the average performance degradation reached to -0.7dB, which did not affect on the subjective quality of reconstructed images at all. And acquiring the more desirable to adopt design SoC for the fast hierarchical motion estimation, we exploit foreground and background search algorithm (FBSA) base on the dual arithmetic processor element(DAPE). It is possible to estimate the large search area motion displacement using a half of number PE in general operation methods. And the proposed architecture of MHME improve the VLSI design hardware through the proposed FBSA structure with DAPE to remove the local memory. The proposed FBSA which use bit array processing in search area can improve structure as like multiple processor array unit(MPAU).

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.44-51
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• 2015

The objective of this study is to characterize a toxicity of Polygalae Radix (PR) in F344 rats and to find a dose levels for the 13 weeks toxicity study. PR is well known as medicinal herb in many Asian countries for treatment of expectorant, tonic, tranquillizer, antipsychotic agent and functional diet for improving memory. However, there is insufficient background information on toxicological evaluation of PR extract to support its safe use. Therefore, we conducted toxicological evaluation of this drug in compliance with OECD and KFDA guideline in this study. The extract of PR was administered orally to F344 rats at dose levels of 0, 500, 1000, 2000, 3500 and 5000 mg/kg/day for 2 weeks. Each group was composed to five male and five female rats. In the result, there were no treatment PR-related adverse changes in food consumption, hematology, clinical chemistry, urinalysis, gross finding at necropsy, organ weight examination. Four males at 5000 mg/kg/day were found dead during the treatment period. These animals showed salivation. The cause of death is still under investigation. The animals treated at 500, 1000, 2000, 3500 and 5000 mg/kg/day showed salivation and all animals at 5000 mg/kg/day exhibited lower body weight and cumulative weight gain in compared to those of control animals. Therefore, we recommend that a dose group of 3500 mg/kg/day is a highest treatment group in 13-week exposure study.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.18-27
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• 2010

In u-GIS environment, GeoSensor environment requires that dynamic data captured from various sensors and static information in terms of features in 2D or 3D are fused together. GeoSensors, the core of this environment, are distributed over a wide area sporadically, and are collected in any size constantly. As a result, storage space could be exceeded because of restricted memory in DSMS. To solve this kind of problems, a lot of related studies are being researched actively. There are typically 3 different methods - Random Load Shedding, Semantic Load Shedding, and Sampling. Random Load Shedding chooses and deletes data in random. Semantic Load Shedding prioritizes data, then deletes it first which has lower priority. Sampling uses statistical operation, computes sampling rate, and sheds load. However, they are not high accuracy because traditional ones do not consider spatial characteristics. In this paper 'Pre-Filtering based Post Load Shedding' are suggested to improve the accuracy of spatial query and to restrict load shedding in DSMS. This method, at first, limits unnecessarily increased loads in stream queue with 'Pre-Filtering'. And then, it processes 'Post-Load Shedding', considering data and spatial status to guarantee the accuracy of result. The suggested method effectively reduces the number of the performance of load shedding, and improves the accuracy of spatial query.

• Korean Journal of Community Nutrition
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• v.6 no.5
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• pp.726-733
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• 2001

This study was designed to investigate the effect of iron supplementation on the iron nutritional status and anemia of high school girls in Korea. One hundred thirty-five female students residing in Ulian metropolitan city in Korea diagnosed as having anemia or iron deficiency participated in this study. One or two tablets of iron medicine(80-160 mg Fe as ferrous sulfate/day) were administered to all participants for 3 months. Subjects were evaluated with a questionaire, measurement of hematological indices before and after iron supplementation. The average height and weight of respondents were 161.62 $\pm$ 4.68 cm and 53.87 $\pm$ 6.10 kg, respectively. Daily intakes of energy were 1597.8 $\pm$ 302.35 kcal(76.0% RDA). Iron intakes were 13.72 $\pm$ 4.17 mg (76.3% of RDA) and calcium intakes were 580.74 $\pm$ 177.21(72.5% of RDA) before iron supp]ementation. At baseline, 63% of all participants had depleted store(serum ferritin 12 ug/ml and/or transferrin saturation(TS) < 14%). After iron supplementation, this proportion declined to 19.3%. 55.6% of subjects had 12 ug/m1 of basal ferritin concentration before iron supplementation, and this proportion declined to 16.3% after iron supplementation. The basal hemoglobin(Hb) concentrations were 12.13 $\pm$ 1.01 g/dl and they increased to 12.79 $\pm$ 0.81 g/dl, which showed significant difference artier iron supplementation(p < 0.001). The basal ferritin and TS(%) were 13.24 $\pm$ 11.66 ng/ml, 18.42 $\pm$ 10.12% and they significantly increased to 32.95 $\pm$ 21.14 ng/ml, 33.53 $\pm$ 16.64%, respectively(p < 0.001). The basal total iron binding protein(TIBC) were 467.81 $\pm$ 97.24 ug/dl and they significantly decreased to 325.05 $\pm$ 48.89 ug/dl(p < 0.001) after iron supplementation. The number of tablets administered was positively correlated with serum iron(t = 0.553, p < 0.01), serum ferritin(t = 0.557, p < 0.01), TS(%)(t = 0.588, p < 0.01) and negatively correlated with TIBC(t= -0.409, p <0.01). The anemia symptoms such as ‘Shortening of breath when going upstairs(p < 0.01)’, ‘Tired out easily(p < 0.01)’, ‘Feeling blue(p < 0.001)’, ‘Decreased ability to concentrate(p < 0.01)’, and ‘Poor memory(p < 0.001)’improved significantly after iron supplementation. In this study, daily iron supplementations were efficacious in improving the iron status and anemic symptoms of female high school students. Regular check-ups and nutrition education for adolescents are necessary because of their vulnerability to iron deficiency. Further studies are needed to determine the minimum effective dose of iron and to examine the adverse effect of long-term iron supplementation.

• Journal of Science Education
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• v.39 no.1
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• pp.58-79
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• 2015

This study is to analyze the 2289 students questionnaires from 3rd to 9th grade students in order to analyze the students' perceptions change aspect by their grade about the frequency and type of students' question during various science class context. After the class contexts proposed in the questionnaire subcategorize into 19 subitems about 4 areas of class content, class pattern, class material and class process, this study examined the frequency and type of students' question during a science class by each item. The results of this study were as follows. First, the type of students' question was that the most frequent was understanding question and the second was memory question and these both types were half frequency. There was no special tendency related the change of students' question type by school year. Second, the frequency of 4th grade students' question was the highest among other school year students and the frequency of students' question was lowered by the higher school year. The change of students' question by school year was the biggest between 3rd and 4th grade. The class strategies for improving the class effect reflect that the various and active students' question by class context and school year stimulates students' thinking and also builds up the active class environment.

• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.373-379
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• 2015

This study aimed to investigate the anti-amnesic effect of perilla oil against trimethyltin (TMT)-induced learning and memory impairment in ICR mice. Perilla oil (2.5 mL/kg of body weight) and soybean oil (2.5 mL/kg of body weight) were administered orally to mice for 3 weeks, and at the end of the experimental period, cognitive behavior was examined by Y-maze and Morris water maze (MWM) tests. Behavioral tests showed that the mice treated with perilla oil had improved cognitive function compared to that in mice administered soybean oil. Analysis of brain tissue showed that perilla oil significantly lowered acetylcholinesterase activity and malondialdehyde (MDA) levels. Oxidized glutathione (GSH)-to-total GSH ratio also decreased from 10.4% to 5.3% in perilla oil-treated mice, but superoxide dismutase (SOD) activity increased from 11.7 to 14.2 U/mg protein. Therefore, these results suggest that the perilla oil could be a potential functional substance for improving cognitive function.

• Journal of Life Science
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• v.27 no.11
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• pp.1308-1314
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• 2017

The Chinese red-headed centipede Scolopendra subspinipes mutilans, a member of the arthropod class Chilopoda, is a traditional medicine used for the treatment of several allergic diseases, such as atopy. S. subspinipes mutilans samples were collected from different regions of South Korea: Sancheong, Gyeongnam; Yeonggwang, Jeonnam and Jeju-do. The nutritional values of the centipedes were analyzed to extend the species' applications. The crude protein and fat contents of all samples were high and ranged from 54.9-55.8% and from 26.8-30.6%, respectively. Essential amino acids were present; lysine was the most common and accounted for 3.4-3.6% of the essential amino acids. Glutamic acid, which assists in improving concentration, memory and other cognitive abilities, was the most common non-essential amino acid at 6.8-7.1%. It had a similar content percentage in all three regions' samples. Additionally, unsaturated fatty acids were present, and oleic acid, which prevents cancer and cardiac disease, was the most common at 41.3-48.6% of each sample. Mercury, a hazardous substance, was detected at a range of 0.08-0.11 mg/kg in all samples; the amount was lower than the standard food allowance. Additionally, no pathogenic microorganisms, such as Escherichia coli and Salmonella spp., were detected. There were no significant differences between the nutritional factors of the S. subspinipes mutilans samples from the three regions. Based on the nutritional analysis, Chinese red-headed centipedes have the potential to be food and medicinal ingredients due to their proteins, essential amino acids, unsaturated fatty acids and nutritive capacities.