• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.995-1000
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• 2010

To investigate the relationship between polychlorinated byphenyls (PCBs) sources and concentration level in sediment, total 63 sediment samples with three-time sampling at one site were measured at 21 sites in Nakdong River. As a result of analysis, total concentrations and toxic equivalent (TEQ) concentration of Dioxin-like PCBs were ranged from 3.0 to 6,600 pg/g-dry with a mean value of 440 pg/g-dry and

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.390-396
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• 2009

The aim of this study was to evaluate endodontic irrigation methods with $EndoVac^{(R)}$ and $EndoActivator^{(R)}$ in the elimination of Enterococcus faecalis from the root canals. Extracted 70 human single-rooted teeth were used. The canals were instrumented by a crown-down technique with .04 taper ProFile to ISO size 40. After the teeth were autoclaved, the canals were inoculated with E. faecalis and incubated for 48 h. The teeth were randomly divided into three experimental groups of 20 teeth each according to canal irrigation methods and two control groups as follows: group 1 - $EndoVac^{(R)}$; group 2 - $EndoActivator^{(R)}$; group 3-Conventional needle irrigation method. After canal irrigation using 2.5% NaOCl. first samples (S1) were taken using sterile paper point. And the canals were filled with sterile brain heart infusion (BHI) broth and incubated for 24 h, then second samples (S2) were taken. The samples were cultured on BHI agar plate to determine the numbers of colony forming units (CFU). In first sampling (S1), only one canal of conventional method among the all experimental groups was positive cultured. In second sampling (S2), $EndoVac^{(R)}$ group showed the least positive culture numbers of E. faecalis. There was statistically significant difference between the $EndoVac^{(R)}$ and conventional needle irrigation methods in the mean value of Log CFU. According to the results of this study, $EndoVac^{(R)}$ showed better efficacy than conventional needle irrigation method in the elimination of E. faecalis from the root canal.

• Biomolecules & Therapeutics
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• v.6 no.2
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• pp.219-224
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• 1998

The bioequivalence of two clarithromvcin products was evaluated with 16 normal male volunteers (age 23-28 yr, body weight 57.5-75.517g) following single oral dose. Test product was ReYon Clarithromycin tablets (ReYon Pharm. Corp., Korea) and reference product was Klarici $d_{R}$ tablets (Abbott Korea). Both products contain 250 mg of clarithromucin. One tablet of the test or the reference product was administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). The determination of clarithromycin was accomplished using a modified agar well diffusion bioassay. As a result of the assay validation, the quantification of clarithromycin in human serum by this technique was possible down to 0.03$\mu$g/ml using 100$\mu$l of serum. The coefficient of variation (C.V.) was less than 10%. Average drug concentrations at each sampling time and pharmacokinetic parameters calculated were not significantly different between two products P>0.05); the area under the curve to last sampling time (24 hr) (AU $Co_{24hr}$ (8.10$\pm$ 1.26 vs 8.22$\pm$ 1.627g . hr/ml), AUC from time zero to infinite (AU $Co_{\infty}$) (8.61 $\pm$ 1.28 vs 8.84$\pm$ 1.71 $\mu$g . hr/ml), maximum plasma concentration ( $C_{msx}$) (0.87$\pm$0.22 vs 0.88$\pm$0.19 $\mu$g/ml) and time to maximum plasma concentration ( $T_{max}$) (2.69 $\pm$0.48 vs 2.56$\pm$ 0.51 hr). The differences of mean AU $Co_{24h}$, $C_{msx}$ and $T_{msx}$ between the two products (1.44, 1.39, and 4.65%, respectively) were less than 20%. The power (1-$\beta$) and treatment difference ($\Delta$) for AU $Co_{24hr}$, and $C_{max}$ were more than 0.8 and less than 0.2, respectivly. Although the power for $T_{max}$ was under 0.8, $T_{max}$. of the two products was not significantly different each other (p>0.05). These results suggest that the bioavailability of ReYon Clarithromycin tablets is not significantly different from that of Klarici $d_{R}$ tablets. Therefore, two products are bioequivalent based on the current results. results.sults.sults.s.s.s.s.s.s.s.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.48-57
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• 2006

This work describes a 12b 200KHz 0.52mA $0.47mm^2$ algorithmic ADC for sensor applications such as motor controls, 3-phase power controls, and CMOS image sensors simultaneously requiring ultra-low power and small size. The proposed ADC is based on the conventional algorithmic architecture with recycling techniques to optimize sampling rate, resolution, chip area, and power consumption. The input SHA with eight input channels for high integration employs a folded-cascode architecture to achieve a required DC gain and a sufficient phase margin. A signal insensitive 3-D fully symmetrical layout with critical signal lines shielded reduces the capacitor and device mismatch of the MDAC. The improved switched bias power-reduction techniques reduce the power consumption of analog amplifiers. Current and voltage references are integrated on the chip with optional off-chip voltage references for low glitch noise. The employed down-sampling clock signal selects the sampling rate of 200KS/s or 10KS/s with a reduced power depending on applications. The prototype ADC in a 0.18um n-well 1P6M CMOS technology demonstrates the measured DNL and INL within 0.76LSB and 2.47LSB. The ADC shows a maximum SNDR and SFDR of 55dB and 70dB at all sampling frequencies up to 200KS/s, respectively. The active die area is $0.47mm^2$ and the chip consumes 0.94mW at 200KS/s and 0.63mW at 10KS/s at a 1.8V supply.

• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.115-122
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• 2004

This study was performed to investigate the behavioral characteristics of Hanwoo(Bos taurus coreanae) cows and their calves. Four cows and their calves were placed in pens. The behaviors of each cow and calf were recorded using a time lapse VCR from 07:00 h to 18:00 h for 6 days and were analyzed using the scan point sampling method. The cow's behaviors in order of frequency were LD(lying down, 25%), ST(standing, 23%), EA(eating, 13%), LR(lying down rumination, 10%) and SR(standing rumination, 7%). The cows spent less than 3% of their time PG(pairwise grooming) and SF(snifting). The calves mainly showed LD(52%), ST(28%), LF (lying flat, 4%), EA(3%) and WA(walking, 3%). The calves spent less than 2% of their time SF(sniffing) and SUK(suckling), The behavioral patterns of cows and their calves at 07:00 h, 12:00 h and 18:00 h were different, especially in ST and LD.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.391-398
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• 2003

Research was conducted to establish the leaf and petiole sap test to diagnose the nutritional status of tomato. The concentrations of $NO_3$, $PO_4$, K, Ca, Mg and $SO_4$ ions extracted from the leaves and petioles in the different positions in a plant were measured and compared with their corresponding inorganic contents in the leaves analyzed by the chemical method. The ionic concentrations in the leaf and petiole sap showed the different values depending on their positions in a plant. The leaves and petioles in the lower positions of a plant had higher concentrations of $NO_3$, Ca, Mg and $SO_4$ ions. In particular, there were greater changes of ionic concentrations and less increases in the leaf length and width from the 9th compound leaf down from the uppermost cluster. On the other hand, the leaflets in a compound leaf had the same ionic concentrations. Therefore, it appeared that the optimal sampling position of leaf and petiole for the sap test is the leaflets of the 9th compound leaf down from the uppermost cluster. A good correlation between the sap test and the chemical analysis of plant showed that the ionic concentrations in the leaf and petiole sap reflect the nutritional status of tomatoes.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.454-460
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• 2012

This study was conducted for determining the influence of Sediment Control Dam dredging on benthic macroinvertebrate communities in mountain stream of Gyeongsangbuk-do. The sediment control dams were surveyed before and after dredging from mountain streams of Yecheon, Yeongju and Bonghwa in Northern part of Gyeongsangbuk-do. Sampling was taken at upper and down from 3 experimental sites and 2 control sites during May to August 2011. The identified species before dredging were 56 belonged to 31 families, 11 orders, 6 classes and 4 phyla, but after dredging it has decreased to 51 species belonged to 27 families, 10 orders, 5 classes and 4 phyla. The microhabitat damage of benthic macroinvertebrates occurred at experimental sites after dredging of sediment control dams led to reduction of the number of species and individuals. Especially, upper stream of experimental sites showed the reduction of an average of 38% species. In general, species diversity indices and species richness indices decreased after dredging; however, dominance indices increased at experimental sites. In the upper stream of experimental sites, the microhabitat damaged and became pool due to dredging. Also, velocity of flow decreased and the river bed became simply due to the sedimentary matter being finer than sand and silt. As a result, composition of functional feeding groups and functional feeding groups were relatively simpler at upper stream and the degree of community differences was greater between upper and down stream. Also, Chironomidae spp., Ephemeridae spp., and Gomphidae spp. to prefer where slow velocity of flow and lentic increased in a greater rate, and the EPT/C index to indicate the balance of the community decreased.

• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.359-366
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• 2010

The purpose of this study is to examine the influence of the leisure constraint of a private security guard on his/her task stress and life satisfaction. The subjects of this study were chosen among the private security guards working in Seoul based private security firms in 2009, and by going through judgement sampling, 300 cases were applied in the final analysis. Collected data went through factor analysis, reliability analysis, regression analysis, and path analysis by using SPSSWIN 17.0. In reference with the reliability of the questionnaire, Cronbach's $\alpha$ was over .600. The conclusion of this study is as following. Firstly, the leisure constraint of a private security guard affects his/her task stress. In other words, when peripheral and individual constraint increase, task stress is intensified, while task stress winds down when interpersonal constraint decreases. Secondly, the leisure constraint of a private security guard affects life satisfaction. That is, when individual constraint goes down, life satisfaction is improved. Thirdly, the task stress of a private security guard affects life satisfaction. when compensation and career development increase, life satisfaction rises. On the other hand when task characteristic is weakened, life satisfaction gets lower. Fourthly, the leisure constraint of a private security guard has a causal influence on task stress and life satisfaction. Accordingly, it becomes apparent that the task stress is a significant variable which intermediates the relation between leisure constraint and life satisfaction.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1391-1401
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• 2019

The KOMPSAT-3A is a high-resolution optical satellite launched in 2015 by Korea Aerospace Research Institute (KARI). KOMPSAT-3A provides Panchromatic (PAN-0.55 m), Multispectral (MS-2.2 m), and Mid-wavelength infrared (MIR_OR-5.5 m) image. However, due to security or military problems, MIR_OR image with 5.5m spatial resolution are provided down sampled at 33 m spatial resolution (MIR_rd). In this study, we propose spatial sharpening method to improve the spatial resolution of MIR_rd image (33 m) using virtual High Frequency (HF) image and optimal fusion factor. Using MS image and MIR_rd image, we generated virtual high resolution (5.5 m) MIR_OR^fus image and then compared them to actual high-resolution MIR_OR image. The test results show that the proposed method merges the spatial resolution of MS image and the spectral information of MIR_rd image efficiently.

• Journal of The Korean Association For Science Education
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• v.33 no.7
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• pp.1471-1485
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• 2013

The purpose of this study was to develop a HAM (Heuristic Attention Model) by analyzing the difference between eye movements according to the science achievement of elementary school students on discrimination task. Science achievement was graded by the results of the Korea national achievement test conducted in 2012 for a random sampling of classes. As an assessment tool to check discrimination task, two discrimination measure problems from TSPS (Test of Science Process Skill, developed in 1994) which were suitable for an eye tracking system were adopted. The subjects of this study were 20 students from the sixth grade who agreed to participate in the research. SMI was used to collect EMD (eye movement data). Experiment 3.2 and BeGaze 3.2 programs were used to plan experiments and analyze EMD. As a result, eye movements of participants in discrimination tasks varied greatly in counts and duration of fixation, first fixation duration, and dwell time, according to students' science achievement and difficulty of the problems. By the analysis of EMD, strategies of the students' problem-solving could be found. During problem solving, subjects' eye movements were affected by visual attention; bottom-up attention, top-down attention and convert attention, and aflunter attention. In conclusion, HAM was developed, and it is believed to help in the development of a science learning program for underachievers.