• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1427-1435
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• 2010

A mixed finite element model was developed using the classical plate theory to analyze the nonlinear bending of a plate. The appropriate weight functions for the constraints integrated over the domain were determined by the Lagrange multiplier method by using the principle of minimum virtual energy; which provides the constitutive relations between force-like variables and strains. All of detail terms of element wise coefficient matrices and associate tangent matrices to be used in the Newton iterative method are presented. Then, the linear solutions of the current model and those of the traditional displacement model under the SS (simple support) boundary conditions were compared with the existing analytical solution. The post-processed images of the nonlinear results of the force-like variables are presented to show the continuity of the solutions at the joint of the element boundaries. Finally, the converged nonlinear finite element solutions of the current model are compared with those of existing traditional displacement model.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.122-131
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• 1994

Journal bearings in the rotating machineries are vulnerable to the contamination or the insufficient supply of lubricating oil, which is likely to be the cause of unexpected shutdown or malfunction of these systems. Various destructive and nondestructive testing methods had been used for the reduction of maintenance cost and the operational safety problems due to the accidents related to bearing damages. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. Experimental schedules for the intervention of foreign particles was composed to be more quantitative and systematic than last study in consideration of minimum oil film thickness and particle size. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. Several parameters such as AE rms level, waveform, AE energy distribution and other AE event parameters are used for analysis and characterization of damage source. The results showed that the history of damage was well correlated with the changes of AE rms level and the type of damage source signal can be verified using other informations such as waveform, distributions of AE parameters etc.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.5
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• pp.375-382
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• 2007

Nondestructive testing (NDT) by using the electromagnetic methods are useful for detecting cracks on the surface and subsurface of the metal. However, when the material contains both ferromagnetic and paramagnetic materials, it is difficult for NDT to detect and analyze cracks using this method. In addition the existence of a partial ferromagnetic material can be incorrectly characterized as a crack in the several cases. On the other hand a large crack has sometimes been misunderstood as a partially magnetized region. Inconel 600 is an important material in atomic energy plant. A nickel film is coated when a crack a appears on an Inconel substrate. Cracks are difficult to detect on the combined material of an Inconel substrate with a nickel film, which are paramagnetic and ferromagnetic material respectively. In this paper, a scan type magnetic camera, which uses a complex induced current-magnetic flux leakage (CIC-MFL) method as a magnetic source and a linearly integrated Hall sensor array (LIHaS) on a wafer as the magnetic sensors, was examined for its ability to detect cracks on the combined material. The evaluation probability of a crack is discussed. In addition the detection probability of the minimum depth was reported.

• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.450-462
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• 2009

So far, many methods for segmenting single images or video have been proposed, but few methods have dealt with multiple images with analogous content. These images, which we term consistent scene images, include concurrent images of a scene and gathered images of a similar foreground, and may be collectively utilized to describe a scene or as input images for multi-view stereo. In this paper, we present a method to segment these images with minimum user input, specifically, manual segmentation of one image, by iteratively propagating information via multi-level cues with adaptive confidence depending on the nature of the images. Propagated cues are used as the bases to compute multi-level potentials in an MRF framework, and segmentation is done by energy minimization. Both cues and potentials are classified as low-, mid-, and high- levels based on whether they pertain to pixels, patches, and shapes. A major aspect of our approach is utilizing mid-level cues to compute low- and mid- level potentials, and high-level cues to compute low-, mid-, and high- level potentials, thereby making use of inherent information. Through this process, the proposed method attempts to maximize the amount of both extracted and utilized information in order to maximize the consistency of the segmentation. We demonstrate the effectiveness of the proposed method on several sets of consistent scene images and provide a comparison with results based only on mid-level cues [1].

• Journal of Biosystems Engineering
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• v.9 no.1
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• pp.22-33
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• 1984

Husk separator is an indispensable equipment in rice milling plants. However, any basic research on the designing and operating criteria of the husk separator have rarely been conducted in Korea. According to the survey results reported recently, grain loss occurs in the process of rice husk separation at custom rice milling plants in Korea and the performance of husk separator has also not been identified. With this regard this study was conducted with a typical commercial husk separator to investigate the effect of the operational factors such as feed rate, blower speed and opening ratio on the velocity distribution in the air duct and the performance of the separator. The results are summerized as follows: 1. The average wind velocity in the primary air duct increased linearly with the blower rpm and the size of air inlet port in both cases of double type and single type operations. 2. The coefficient of variation in the horizontal wind velocities in the primary air duct was the minimum when the opening ratio was 0.22 ($0.052m^2$ of air inlet port) in both cases of single type and double type operations regardless of the blower speeds used in this test. The average wind velocity at the upper part of air duct was greater by 2-5 m/s than the velocity at the bottom part in double type operation. In case of single type operation, however, the average velocity in the middle part was greater than the upper or bottom part when the opening ratio was greater than 0.74. 3. The relationship between the overall effectiveness of separation(Ed for double type and Es for single type) and the average wind velocity (Va) in the primary air duct was expressed in the following quadratic functions. $$Ed=-190.84+106.18Va-10.052Va^2$$ ($r^2$ = 0.97782) $$Es=-223.76+106.23Va-9.1935Va^2$$ ($r^2$ = 0.97029) The average wind velocity required to obtain the overall effectiveness of separation more than 80% ranged from 4.04 m/sec to 5.84 m/sec in case of double type operation, and from 4.70 m/sec to 6.20 m/sec in case of single type. 4. An optimum wind velocity can be obtained with an increase in the blower speed or the size of air inlet port as presented in Figure 8. There was a tendency that the faster the blower speed, the narrower the control range of the air inlet port. 5. The feed rates (1850kg/hr and 2100kg/hr) adopted in this experiment did not bring about a significant difference in both the overall effectiveness of separation and the power consumption. 6. The energy consumption increased cubically with the blower speed but linearly with the size of the air inlet port. On the basis of the results described in items 1, 3, and 6, it would be more economic to adjust the size of the air inlet port larger with a relatively low blower speed than to adjust the size smaller with a relatively high speed.

• Journal of Nutrition and Health
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• v.31 no.4
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• pp.729-738
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• 1998

Antioxidants such as vitamin C and E may play a preventive role in the development of cancer and coronary heart disease. The status of vitamins C and E may be affected by lifestyle habits such as smoking , drinking, and exercise. These habits can modify the dietary requirements of vitamin C and vitamin E. the purpose of this study was to determine whether Korean young healthy men and women consume vitamins C and E in sufficient quantities relative to their lifestyle habits. Among the participants in this study, 52% of the men and none of the women were smokers. ; 84% of all subjects drank alcohol more than once a week ; and the men exercised more often than the women. The concentrations of serum total , HDL-, and LDL- cholesterol were higher in the women than in the men, but the serum triglyceride concentrations were higher in the men than in the women. The men consumed less satuated fat than the women (p<0.05) . The daily intakes of vitamin C for the men and the women were 47.1mg and 65.6mg, respectively. On the other hand , the daily vitamin E intake was higher in the men (11.8mg) than women(6.9mg). The serum $\alpha$-tocopherol concentrations of all subjects were in a normal range, and in no subjects were they below the minimum value of ranges. However, about 19% of male subjects and 10% of female subjects showed deficient status, although the mean serum vitamin C levels were normal . Lifestyle habits fo the sort mentioned above have little influence on the serum vitamin C and $\alpha$-tocopherol concentrations. The serum $\alpha$-tocopherol concentration had a positive correlation with total fat and alcohol consumption. The serum vitamin C concentration was positively associated with regular exercise, but it was negatively correlated with the number of cigarettes smoked. Meanwhile, the serum lipid persoxide concentration , the indirect index of oxidative stress, was influenced by certain variable such as body mass index , the number of cigarettes smoked , alcohol consumption, energy expenditure, vitamin C intake, and serum ${\gamma}$-tocopherol concentration. Serum lipid peroxide concentration was positively associated with body mass index, the number of cigarette smoked , serum triglyceride , and HDL-cholesterol concentration. In conclusion , the vitamin E requirements of the subjects were met by the Recommended Daily Allowance (RDA) regardless of lifestyle habits. However, serum vitamin C concentrations showed individual variation and was below the normal ranges. Smoking and exercise influenced serum vitamin C concentration. Therefore, a reevaluation of the requirements of vitamin C relative to lifestyle habits is necessary.

• Journal of Astronomy and Space Sciences
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• v.26 no.4
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• pp.521-528
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• 2009

While it is well known that space environment can produce spacecraft anomaly, defining space environment effects for each anomalies is difficult. This is caused by the fact that spacecraft anomaly shows various symptoms and reproducing it is impossible. In this study, we try to find the conditions of when spacecraft failures happen more frequently and give satellite operators useful information. Especially, our study focuses on the geosynchronous satellites which cost is high and required high reliability. We used satellite anomaly data given by Satellite News Digest which is internet newspaper providing space industry news. In our analysis, 88 anomaly cases occurred from 1997 to 2008 shows bad corelation with Kp index. Satellite malfunctions were likely to happen in spring and fall and in local time from midnight to dawn. In addition, we found the probability of anomaly increase when high energy electron flux is high. This is more clearly appeared in solar minimum than maximum period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6602-6609
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• 2013

This study is expected to provide background data for establishing mitigation measures for malodor and for comparing complex odor criteria. The impact of malodor at the afflicted locations was analyzed using Industrial Source Complex Short Term 3 (ISCST3) model, which was recommended by the EPA. The Odor Emission Rates (ODR) for piglets and hogs were predicted based on the average, minimum, and maximum emission rates as classification. The forecasting result of the complex odor modelling of pigsty showed that tolerance limit was exceeded at an adjacent administration building, but tolerance limit was not surpassed at an afflicted location which was within 185m from the pigsty. The ISCST3 modelling of the satisfactory ODR for tolerance limit was accomplished at the administration building. From the prediction of this modelling, maximum emission rates based on 1hr at administration building were 10.59~52.93, 19.05~31.76, and 10.59 $OU/m^3/s/m^2$ at emission rates of 50%, 30%, and 10%. This emission rate was slightly higher than the tolerance limit of 10.00 $OU/m^3/s/m^2$. However, it was inferred that the tolerance limit could be satisfied if the emission rate of 10% was controlled.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1481-1497
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• 1998

The purpose of this study was to determine the relation between serum lipid profiles, apolipoprotein E phenotype, and dietary patterns in a cross-section of healthy individuals from Cheju-Do. Age, gender, anthropometric measurements, blood pressure, dietary consumption, drinking / smoking habits and menopausal status were surveyed. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, fasting blood glucose, and insulin levels were measured from overnight fasting blood. The study involved a total of 286 individuals(147 men and 139 women) between the ages of 20 and 60 years old. All of the subjects were recruited from a population of healthy individuals living in Cheju-Do. The results of the study are as follows : 1) Among the males, those in their 20's had the maximum food intake, while those in their 40's had the minimum food intake. For the females, food intake was the highest for those in their 30's. Energy and nutrient intakes were directly proportional to the amount of food intake. Men in their 30's were heavier than other men and women in their 40's were heavier than other women. The activity index for men in their 20's and 30's appeared to be lower than that of men above 40. The activity index of women in their 20's appeared to be lowest among all aged groups, and the index appeared to increase from the age of 30 onwards. 2) In terms of changes In serum constituents with age, men in their 40's appeared to have the highest levels of serum constituents such as lipids, glucose, and insulin. Men in their 50's showed the highest levels of serum LDL-cholesterol and glucose. Men in their 30's showed peak levels of serum triglycerides. On the other hand, women in their 50's appeared to have peak levels of serum total cholesterol, LDL-cholesterol, and triglycerides. There was no ch:ange with age in HDL-cholesterol and insulin levels for men and women. The percentage of the subjects had the following apo E phenotypes : E3/3, 91.3% ; E3/2, 5.4% ; E4/3, 2.5% ; E4/2, 0.7%. Lee's reserch with Korean female college students showed that the percentage of ApoE3/3, E3/2, E 4/2, E4/3, and E4/4 were 84.8%, 6.7%, 6.7%, 0.9%, 0.9%, respectively. The number of samples with ApoE mutation was so small that there was no statistical significance in the relation between apolipoprotein E phenotype and se겨m lipids. 3) To investigate the relati onship between weight and serum constituents, the subjects of this study were divided into three groups by BMI underweight, normal weight, and overweight. The serum constituents of men and women below the age 40 in the overweight groups belonged to the normal domain. On the other hand, serum cholesterol levels of both men and women above the age 40 in the overweight groups remained in the borderline-high region(above 200mg/dl), and the mean value of LDL-cholesterol(above 130mg/dl) and triglycerides of men were above normal. Fasting blood glucose levels also remained in the borderline-high region. Total cholesterol levels of women above the age 40 in the overweight group was in the borderline-high region. (Korean J Nutrition 31(9) : 1481-1497, 1998)

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.22-28
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• 2007

Spectrum spreading, in its general form, can be conceived as an artificial expansion of the signal bandwidth with respect to the minimum Nyquist band required to transmit the desired information. Spreading can be functional to several objectives, including resilience to interference and jammers and reduction of power spectral density levels. In the paper, signal spreading is manly used for increasing the received energy, thus satisfying link budget constraints, for terminals with low aperture antennas, without increasing the transmitted EIRP. As a matter of fact, in many mobile scenarios, even when MODCOD configurations with very low spectral efficiency (i.e. QPSK-1/4) in DVB-S2 standard, are used, the link budget cannot be closed. Spectrum spreading has been recently proposed as a technique to improve system performance without introducing additional MODCOD configurations under the constraint of fixed power spectrum density level at the transmitter side. To this aim, the design of spectrum spreading techniques shall keep into consideration requirements such as spectrum mask, physical layer performance, link budget, hardware reuse, robustness, complexity, and backward compliance with existing commercial equipments. The proposed implementation allows to fully reuse the standard DVB-S2 circuitry and is inserted as an 'inner layer' in the standard DVB-S2 chain.