• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.457-462
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• 2008

The objective of this study was to determine appropriate sample size that simulated different assumptions for diagnostic test characteristics and true prevalences when designing serological surveillance plan for pullorum disease and fowl typhoid in domestic poultry production. The number of flocks and total number of chickens to be sampled was obtained to provide 95% confidence of detecting at least one infected flock, taking imperfect diagnostic tests into account. Due to lack of reliable data, within infected flock prevalence (WFP) was assumed to follow minimum 1%, most likely 5% and maximum 9% and true flock prevalence of 0.1%, 0.5% and 1% in order. Sensitivity were modeled using the Pert distribution: minimum 75%, most likely 80% and maximum 90% for plate agglutination test and 80%, 85%, and 90% for ELISA test. Similarly, the specificity was modeled 85%, 90%, 95% for plate agglutination test and 90%, 95%, 99% for ELISA test. In accordance with the current regulation, flock-level test characteristics calculated assuming that 30 samples are taken from per flock. The model showed that the current 112,000 annual number of testing plan which is based on random selection of flocks is far beyond the sample size estimated in this study. The sample size was further reduced with increased sensitivity and specificity of the test and decreased WFP. The effect of increasing samples per flock on total sample size to be sampled and optimal combination of sensitivity and specificity of the test for the purpose of the surveillance is discussed regarding cost.

• Journal of the Korean Society of Safety
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• v.24 no.5
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• pp.92-100
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• 2009

This study evaluated the effects of the syllable number(one, two), font type(gothic, myung), color contrast (black on white, white on black), display type(paper, LCD), age(20s, 60s) and character size(2~80pt) on the Korean characters' legibility. Total twenty subjects from two age groups (20s: n=10, 60s: n=10, five male and five female in each group) participated in the legibility test. A target panel was presented in the distance of 50 cm, and subjects conducted a reading tests for, in total, 16 treatment conditions (full combination of syllable number, font type, color contrast and display type). Results showed that two-syllable words revealed better legibility than one-syllable character. The main effects of the age, display type, font type, color contrast, and character size were statistically significant(p<0.01). Paper showed better legibility than LCD, particularly in the 20s and in the character sizes of less than 9pt. Gothic revealed more correct answers than Myung, particularly in the 60s, paper, and white on black conditions. It is expected that these results can provide basic data for the determination of the Korean characters' minimum legible size standards. For example, the minimum legible size for the Gothic and black on white characters presented in the paper should be 5pt for 20s and 1lpt for 60s if the 75% correct reading(3 correct answers in this study) was applied for the legibility criterion.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2505-2511
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• 2014

Indium oxide nanocrystals ($In_2O_3$ NCs) with sizes of 5.5 nm-10 nm were synthesized by hot injection of the mixture precursors, indium acetate and oleic acid, into alcohol solution (1-octadecanol and 1-octadecence mixture). Field emission transmission electron microscopy (FE-TEM), High resolution X-Ray diffraction (X-ray), Nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FT-IR) were employed to investigate the size, surface molecular structure, and crystallinity of the synthesized $In_2O_3$ NCs. When covered by oleic acid as a capping group, the $In_2O_3$ NCs had a high crystallinity with a cubic structure, demonstrating a narrow size distribution. A high mobility of $2.51cm^2/V{\cdot}s$ and an on/off current ratio of about $1.0{\times}10^3$ were observed with an $In_2O_3$ NCs thin film transistor (TFT) device, where the channel layer of $In_2O_3$ NCs thin films were formed by a solution process of spin coating, cured at a relatively low temperature, $350^{\circ}C$. A size-dependent, non-monotonic trend on electron mobility was distinctly observed: the electron mobility increased from $0.43cm^2/V{\cdot}s$ for NCs with a 5.5 nm diameter to $2.51cm^2/V{\cdot}s$ for NCs with a diameter of 7.1 nm, and then decreased for NCs larger than 7.1 nm. This phenomenon is clearly explained by the combination of a smaller number of hops, a decrease in charging energy, and a decrease in electronic coupling with the increasing NC size, where the crossover diameter is estimated to be 7.1 nm. The decrease in electronic coupling proved to be the decisive factor giving rise to the decrease in the mobility associated with increasing size in the larger NCs above the crossover diameter.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.889-894
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• 1999

Preparation of micron size polymer particles which have desired morphology, size, and structure by emulsion polymerization is very difficult due to coagulation of latex particles and formation of second generation particles. But there are attractive merits such as preparation of structural and functional polymer particles in seeded emulsion polymerization. Seeded emulsion polymerization of n-butyl acrylate(BA) was carried out to investigate the effects of stirring rate, reaction temperature, concentration of initiator, emulsifier, and cross-linking agent on the particle size and size distribution. By the combination of suitable reaction conditions, we succeeded in preparing $0.14{\sim}3.67{\mu}m$ diameter of poly(n-butyl acrylate)(PBA) particles using sequential seeded emulsion polymerization.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.80-87
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• 2021

Risk assessment techniques are processes used to evaluate hazardous risk factors in construction sites, facilities, raw materials, machinery, and equipment, and to estimate the size of risk that could lead to injury or disease, and establish countermeasures. The most important thing in assessing risk is calculating the size of the risk. If the size of the risk cannot be calculated objectively and quantitatively, all members who participated in the evaluation would passively engage in establishing and implementing appropriate measures. Therefore, this study focused on predicting accidents that are expected to occur in the future based on past occupational accident statistics, and quantifying the size of the risk in an overview. The technique employed in this study differs from other risk assessment techniques in that the subjective elements of evaluators were excluded as much as possible by utilizing past occupational accident statistics. This study aims to calculate the size of the risk, regardless of evaluators, such as a manager, supervisor, safety manager, or employee. The size of the risk is the combination of the likelihood and severity of an accident. In this study, the likelihood of an accident was evaluated using the theory of Bud Accident Chainability, and the severity of an accident was calculated using the occupational accident statistics over the past five years according to the accident classification by the International Labor Organization.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.57-63
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• 2010

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using a sandwich method as carbonaceous material on each type of storable electrode with $20{\times}15$[mm] cell size. Carbon/active carbon cell was fabricated using sol-gel process with $120[^{\circ}C]$ dry temperature in 2hour and using sintering process with $500[^{\circ}C]$ in 2hour. The effect of sintering temperature on carbon properties was also investigated with an X-ray diffraction technique to get the best sintering temperature. The detail of the fabrication process will be explained. Active carbon as carbonaceous material has a better capacitance in storable electrode with mean thickness $32[{\mu}m]$ and with particle size $1[{\mu}m]$ to $4.5[{\mu}m]$ in $20{\times}15$[mm] sample size of storable electrode.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1939-1944
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• 2003

This paper presents a global path planning algorithm based on a visibility graph method, and applies additionally various constraints for constructing the reduced visibility graph. The modification algorithm for generating the rounded path is applied to the globally shortest path of the visibility graph using the robot size constraint in order to avoid the obstacle. In order to check the visibility in given 3D map data, 3D CAD data with VRML format is projected to the 2D plane of the mobile robot, and the projected map is converted into an image for easy map analysis. The image processing are applied to this grid map for extracting the obstacles and the free space. Generally, the tree size of visibility graph is proportional to the factorial of the number of the corner points. In order to reduce the tree size and search the shortest path efficiently, the various constraints are proposed. After short paths that crosses the corner points of obstacles lists up, the shortest path among these paths is selected and it is modified to the combination of the line path and the arc path for the mobile robot to avoid the obstacles and follow the rounded path in the environment. The proposed path planning algorithm is applied to the mobile robot LCAR-III.

• Journal of the Korean housing association
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• v.23 no.2
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• pp.69-77
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• 2012

The purpose of this study was to explore housing cost burden of young single- or two-person households in the United States who have recently moved for job-related reasons. Total 580 households were selected from 2009 American Housing Survey public-use microdata for data analysis. The findings are as follows: (1) Targeted single-person households were characterized as younger households with higher educational attainment, lower household income, and greater proportion of renters, multifamily housing residents and households with housing cost burden than other households; (2) two-person households showed a higher income level and lower housing cost burden; (3) characteristics that showed significant influences on housing cost burden were household size, householder's age, gender, race and educational attainment, household income level and tenure type; and (4) a linear combination of household size, household income, whether or not a low-income household, residency in metropolitan area, and home structural type were found to be most efficient to predict a single- or two-person household's housing cost burden regardless of the household size.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.411-414
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• 2009

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using simple sandwich capacitor electrode method as carbonaceous material on each type of capacitor electrodes with 20 ${\times}$ 15 mm cell size. Carbon/active carbon cell was fabricated using sol-gel process with 120oC dry temperature in l hour and using sintering process with 500oC in 2 hour. The effect of sintering temperature on carbon properties was also investigated with X-ray diffraction technique to get the best sintering temperature. The detail of fabrication process will be explained. Elemental composition in electrode material can be measured using quantitative spectroscopic as and a cyclic voltammetric technique was used to study the combined effects of electrode material and effect of annealing temperature and also time on the capacitance of thermally treated in capacitor electrode. In this work, characterization impedance technique is used to measurement of capacitance and giving complementary results. Active carbon as carbonaceous material has a better capacitance in charge/discharge process with mean thickness $32{\mu}m$ and with particle size $1{\mu}m$ to $4.5{\mu}m$ in 20 ${\times}$ 15 mm sample size of capacitor electrode.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.