• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.451-464
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• 2014

This study used numerical methods to investigates investigate the exhaust gas recirculation (EGR) effect under the condition of boost pressure condition on a homogeneous charge compression ignition (HCCI) combustion engine using numerical methods. The detailed chemical-kinetic mechanisms and thermodynamic parameters for n-heptane, iso-octane, and PRF50 from the Lawrence Livermore National Laboratory (LLNL) are were used for this study. The combustion phase affects the efficiency and power. To exclude these effects, this study decided to maintain a 50 burn point (CA50) at 5 CA after top dead center aTDC. The results showed that the EGR increased, but the low temperature heat release (LTHR), negative temperature coefficient (NTC), and high temperature heat release (HTHR) were weakened due by theto effect of the O2 reduction. The combined EGR and boost pressure enhanced the autoignition reactivity, Hhence, the LTHR, NTC, and HTHR were enhanced, and the heat-release rate was increased. also In addition, EGR decraeased the indicated mean effective pressure (IMEP), but the combined EGR and boost pressure increased the IMEP. As a results, combining the ed EGR and boost pressure was effective to at increase increasing the IMEP and maintaining the a low PRR.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2461-2476
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• 2013

To assess environmental contamination with carcinogens, carbonaceous compounds, water-soluble ionic species and trace gaseous species were identified and quantified every three hours for three days st three different atmospheric layer at the heart of chiang-Mai, bangkok and hat-Yai from December 2006 to February 2007. A DRI model 2001 Themal/Optical Carbon Analyzer with the IMPROVE thermal/optical reflectance (TOR) protocol was used to quantify the organic carbon(OC) and elemental carbon content in $PM_{10}$. Diurnal and vertical variability was also carefully investigated. In general, OC and EC contenttration shoeed the highest values at the monitoring period o 21.00-00.00 as consequences of human activities at night bazaar coupled with reduction of mixing layer, decreased wind speed and termination of photolysis nighttime. Morning peaks of carboaceous compounds were observed during the sampling period of 06:00 -09:00, emphasizing the main contribution of traffic emission in the three cities. The estimation of incremental lifetime partculate matter exposure (ILPE) raises concern of high risk of carbonaceous accumulation over workers and residents living close to the observatory sites. The average values of incremental lifrtime particulate matter exposure (ILPE) of total carbon at Baiyoke Suit Hotel and Baiyoke Sky Hotel are approsimately ten time shigher then those air sample collected at prince of songkla University Hat-Yai campus corpse incinerator and fish-can maufacturing factory but only slightly higher than those of rice straw burnig in Songkla province. This indicates a high risk of developing lung cancer and other respiratory diseases across workers and residents living in high buildings located in Pratunam area. Using knowledge of carbonaceous fractions in $PM_{10}$, one can estimate the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). Dachs-Eisenreich model highlights the crucial role of adsorption in gas-particle partitioning of low molecular weight PAHs, whereas both absorption and adsorption tend to account for gas-particle partitioning of high molecular weight PAHs in urban residential zones of Thailand. Interestingly, the absorption mode alone plays a minor role in gas-partcle partitiining of PAHs in Chiang-Mai, Bangkok and hat-Yai.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.577-584
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• 2011

A series of field and laboratory permeability tests were performed to investigate the pore-clogging phenomenon of porous concrete used for pavement materials of a road. The field permeability tests were conducted for 37 study points in Jeju city, using the porous concretes with 13mm of maximum coarse aggregate ($G_{max}$). The results show that the service life of porous concrete is about 22 months when the permeability of the porous concrete is designed for 0.01 cm/sec. Some specimens were made with the purpose of recreating pore-clogging phenomenon. Tests were done for injected concentration of pore-clogging materials or size of maximum coarse aggregates ($G_{max}$). The test results demonstrated that relatively long in service life experienced with small amount of injected concentration of pore-clogging materials, whereas relatively short in service life experienced with a reduction in size of maximum coarse aggregates ($G_{max}$). In conclusion, the service life of porous concrete is in proportion to the concentration of pore-clogging material but it is in inverse proportion to the size of maximum coarse aggregate ($G_{max}$). Thus, the persisting period of porous concrete can be determined with respect to concentration of pore-clogging materials or size of maximum coarse aggregates ($G_{max}$).

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.106-111
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• 2007

The current study was conducted to determine the optimum length of feed withdrawal for pre-harvest broilers. A total of three hundred broilers were sampled from an industrial population, and 30 chicks for each weight group (e.g., 1.5 and 2.5 kg) were randomly assigned to feed withdrawal treatments for 0, 3, 6, 9 and 12 h. Weight loss, yield, muscle pH, objective meat color and weights of gastro intestinal contents, crop, gizzard, provenriculus, small intestine, caecum, and rectum were determined. Live weight loss was significantly (p<0.05) increased as length of feed withdrawal extended. A significant (p<0.05) carcass yield for both 1.5 and 2.5 kg groups coincided after 9 and 6 h feed withdrawal, respectively. Net weights of intestinal contents for crop and gizzard were significantly (p<0.05) reduced by 6 h, and the reduction for proventriculus and small intestine occurred from 3 h. A noticeable effect of feed withdrawal on pH for breast muscle at 3 h postmortem occurred only when chicks were fasted for 3 h of which pH (6.05) was significantly (p<0.05) higher than that for other groups including the control (5.74). There was a linear tendency of higher lightness (Hunter L* value) numerically for chicks fasted for longer periods. The highest coefficient of determinations of regression models to estimate weight loss as a function of fasting period and body weights were achieved, when the models included both linear and quadratic terms for fasting period, and linear term for both 1.5 ($R^2=0.76$) and 2.5 kg ($R^2=0.78$) body weight groups. Given the practical aspect, approximately 1.5 kg of body weight is dominant, weight loss could be predicted by the following function; live weight $loss=26.6-0.28{\times}(fasting period)^2+12.34{\times}pasting\;period-0.012{\times}body\;weight$, $R^2=0.76$. Current data implied that the optimum fasting time for pre-slaughter chicks varied depending on slaughter weight; 6 and 9-h fasting were recommendable for 2.5 and 1.5 kg chicks, with little effect on objective meat color.

• Journal of Korean Academy of Nursing
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• v.23 no.2
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• pp.157-169
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• 1993

The most effective modality for cold application and the length of the application have not been determined despite many studies about the use of cold. A quasi-experimental study was conducted to examine the most effective modality among three methods of cold application, the most effective length of time for the application and the continuing effect after each type of cold application. Thirty adult patients admitted to medical and neurosurgical unit and with high fever (above 38.2 ℃) were assigned randomly to each of three cold ap-plication methods : (a) ice bag: (b) cold compress; and (c) tepid water sponge bath. Each method was applied to the whole anterior surface except the face and neck with the patient in the supine pos-ition. Rectal temperatures and skin temperatures (mid chest, upper arm, thigh and leg) were measured be-fore each application and every 10 minutes during ,each application for a period of 60 minutes. They were also measured every 10 minutes for 30 minutes after each cold application was finished. The experiments were carried out from Dec. 22. 1992 through Feb. 26, 1993. The data were analysed using means, ANCOVA Sheffe test and Pearson's Correlation Coefficient. The results of this study are as follows : 1. There were no significant differences among the three cold application methods in the reduction of body temperature, 2. Among the ice bag, cold compress and tepid water sponge bath groups, the ice bag proved to be the most effective method for lowering skin temperature while the cold compress was least effective. 3. Both rectal and skin temperature continued to decrease during the 60 minutes of cold application, but the hunting phenomena was not observed at any of the cold application sites. 4. There were no significant correlations between mean rectal and skin temperatures. 5. Skin temperatures according to the cold application sites decreased to a range of 3.46℃ to 5.20℃ (mid chest), a range of 4.48℃ 4.96℃ (upper arm), a range of 3.86℃ to 5.05℃ (thigh), and a range of 5.42℃ -7.12℃ (leg ). 6. In continuing effect after the cold applications were finished, rectal temperatures according to ice bag, cold compress and tepid sponge bath decreased to 0.29℃, 0.23℃ and 0.09℃ respectively, while the mean skin temperatures increased to 2.39℃ , 2.04℃ and 2.22℃ respectively. In this experiment the ice bag was the most effective modality for lowering skin temperature. when-ever cold is applied for systemic effect, the continuing effect of cold should be considered. The determination of the most effective length of time for cold application needs further study.

• Journal of Korean Academy of Nursing
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• v.28 no.2
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• pp.329-343
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• 1998

This study was designed to identify the relationship between perceived pain, family support and quality of life in patients with ankylosing spondylitis. The purpose of this study was to contribute to the theoretical understanding of the relationship of these three variables and eventually to more effective adaptation of patients to their situation. The subjects for this study were the 68 patients who had been diagnosed with ankylosing spondylitis and registered as out-patients in the Rheumatism Center of one university hospital in Seoul. The data were collected during the period from October 10, 1997 to December 20, 1997, Pain was measured using the perceived pain scale(VAS : Visual Analog Scale)developed by Calm(1993), family support using the scale developed by Kang Hyun Suk (1985) and Quality of Life using the scale developed by Ro Yoo Ja(1988). The data were analyzed by descriptive statistics, Frequencies, Pearson correlation coefficient, using the SPSS program. The results of this can be summarized as followings. 1. The mean perceived pain score was 5. 13 with a range of 2 to 10. 2. The mean perceived family support score was 41.08$\pm$5.34 with a range of 20 to 50. 3. The mean perceived quality of life score was 134.07$\pm$19.82 with a range of 83 to 176. 4. Significant statistical difference was found between family support and quality of life (r=.331, p<0.001). A significant negative statistical difference was found between the family support and quality of life and pain(r=-.250, p<0.05, r=-.460, p<0.001). 5. General characteristics related to pain were exercise (t=4.72, p<0.0006). 6. General characteristics related to family support were age(F=2.65, p<0.0246), educational level (F=2.84, p<0.0282) and exercise (t=3.24, p<0.0452). 7. General characteristics related to quality of life were educational level (F=3.03, p<0.0392) and exercise (t=3.12, p<0.0465). It was found that the higher the level perceived pain, the lower the degree of perceived family support and the quality of life. It was also found that the higher the degree of perceived family support, the higher the degree of perceived quality of life. Accordingly, the conclusions from this study are that reduction of pain is achieved through the family support. Therefore, it is proposed that family support is an appropriate nursing intervention to improve the quality of life of patients with ankylosing spondylitis.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.195-201
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• 2014

In this study, face recognition system was designed based on polynomial Radial Basis Function Neural Networks(pRBFNNs) pattern classifier using 2-directional 2-dimensional principal component analysis algorithm. Existing one dimensional PCA leads to the reduction of dimension of image expressed by the multiplication of rows and columns. However $(2D)^2PCA$(2-Directional 2-Dimensional Principal Components Analysis) is conducted to reduce dimension to each row and column of image. and then the proposed intelligent pattern classifier evaluates performance using reduced images. The proposed pRBFNNs consist of three functional modules such as the condition part, the conclusion part, and the inference part. In the condition part of fuzzy rules, input space is partitioned with the aid of fuzzy c-means clustering. In the conclusion part of rules. the connection weight of RBFNNs is represented as the linear type of polynomial. The essential design parameters (including the number of inputs and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. Using Yale and AT&T dataset widely used in face recognition, the recognition rate is obtained and evaluated. Additionally IC&CI Lab dataset is experimented with for performance evaluation.

• Journal of the Korean Chemical Society
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• v.26 no.6
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• pp.369-377
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• 1982

The technique of combined-measurement of reflectance and ellipsometric parameters was used for studying the anodic film formed on nickel surface in basic solutions. An ellipsometer was automated for transient measurements by way of modulating the plane-polarized light with the Faraday effect. Surface film was formed electrochemically by applying a potential step from the reduction potential range to the passivation range on a polished, high-purity, polycrystalline nickel specimen. From that instant, the changes in the reflectance(r) and the ellipsometric parameters(${\Delta},{\Psi}$) of the surface film were recorded by the automatic ellipsometer. Three exact simultaneous equations including these optical signals, ${\Delta},{\Psi}$ and r were solved numerically with a computer in order to determine the optical properties, n, k, and the thickness, ${\tau}$, of the surface film. From the computed results which showed dependence on pH and time, it was found that passivation of nickel can be effectively attained by surface film thinner than $15{\AA}$ and this passivation film has a small optical absorption coefficient. It seemed that a high pH environment enhances the rate of passivation and is favorable for a denser structure of the surface film. The experimental evidence is in accordance with the hypothesis that the composition of the passive film can be approximated by $Ni(OH)_2$ in the early stage of passivation and that as time passes the composition changes partially toward that of NiO through dehydration.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.63-70
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• 2009

This study is part of an ongoing research project on the development of a sound-absorbing lightweight foamed concrete manufactured by a hydro-thermal reaction between silica and calcium. As the silica source, pulverized bottom ash was used, and as several cementitious powders of ordinary portland cement, alumina cement and calcium hydroxide were used. Manufacture of foamed concrete was accomplished using the pre-foaming method to make a continuous pore system, which is the method of making the foam by using a foaming agent, then making the slurry by mixing the foam, water, and powders. The experiment factors are W/B, foam agent dilution ratio, and foam ratio, and test items are compressive strength, dry density, void ratio, and absorption rate, as evaluated by NRC. The experiment results showed that the sound absorption of lightweight foamed concrete satisfied NRC requirements for the absorbing materials in most of the experiments. It is thus concluded that foam ratio was the most dominant factor, and significantly affected all properties of lightweight foamed concrete in this study. W/B rarely affected total void ratio and continuous void ratio as well as compressive strength, and dry density and foam agent dilution ratio also had little effect onalmost all properties. The analysis of the correlation between NRC, absorption time, continuous void ratio, and absorption time showed that the interrelationship of the continuous void ratio was high.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.31-36
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• 2009

The purpose of this study is to measure the tube voltage, the tube current/volume, exposure time and exposure dose of diagnostic X-ray unit in each doctor offices, hospitals and general hospitals for evaluating the performance of such device, to learn the method and technology of its measurement and to suggest its importance. Research subjects were total 30 X-ray units and divided into groups of 10 X-ray units each. The tube voltage, the tube current/volume, exposure time and exposure dose were measured using percentage average error, and then reproducibility of exposure dose was measured through calculating coefficient of variation. The results are like followings; The tube voltage correctness examination showed that incongruent devices among total 30 X-ray units were 5 devices (16.7%). The tube current correctness examination showed that incongruent X-ray units were 3 devices (10.0%). The tube current volume correctness examination showed that incongruent X-ray units were 4 devices (13.3%). Finally, according to exposure time correctness examination, incongruent X-ray units were 5 devices (16.7%) and according to reproducibility examination of exposure dose, incongruent X-ray units were 7 devices (23.3%). Above results showed serious problem in performance management based on management regulation of diagnostic X-ray unit; it means that regular checkout and safety management are required, and as doing so, patients will be able to receive good quality of medical service by the reduction of radiation exposure time, image quality administration, unnecessary retake and etc. Therefore, this study suggests that the performance of diagnostic X-ray units should be checked regularly.