• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.7-12
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• 2002

This study is aimed to find the scouring mechanism at the toe of rubble mound structures. To investigate the characteristics of scouring in front of the structure, experiments were performed with regular waves in a 2-D flume. The results of this study are as follows. 1) It can be said the characteristics of incident wave causes rolling and sliding of armour block. The difference of wave pressure on the slope, internal flow as well as settlement of armour block due to the weight cause scouring. 2) It is observed that scouring depth at the toe increased when wave height or period increased. The location of ultimate scouring and deposition depth moved seaward when wave period increased. 3) The failure of rubble mound structure was caused by waves or scouring. Failure by erosion increased with high waves and long waves. 4) Using surf-similarity parameter including characteristics of incident waves and structure, scouring and deposition pattern were found and their limit was formulated.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.34-40
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• 1997

Intervalence subband absroption of normally incident infrared radiation in p-type InGaAs-InAlAs coupled quantum well (CQW) is theoretically investigated by the multiband effective mass formalism. By solving a 4*4 luttinger-kohn hamitonian, we calculate valence subband structures, intervalence subband transition matrix elements, and absorption coefficient spectrum in the CQW which consists of a wider well, a thinner well and a barreir between them. Using the flexible design parameters given to the valence band CQW structure, we show that the absorption coefficient profile can be tailored. For a carefully designed CQW, theabsorption coefficient cn be made to maintain a large value over a wider wavelength range of incident infrared radiation compared with that shown in intersubband absorption in usual single quantum well.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.2
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• pp.44-54
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• 1985

The high resolution of positron emission tomography, in particular, requires the use of detector crystals of narrow width but still with sufficiently high detection efficiency. If the crystal width is reduced to several millimeters, degradation of detection efficiency and leakage coefficient becomes significant, particularly in case of obliquely incident photons. Alleviation of such a problem can be made possible by modification of the detector shape from the conventional rectangular type to a wed농e type. The Proposed wedge shape makes the absorption length longer for obliquely incident photons, thus increasing the detection efficiency and suppressing leakage coefficient. For the BGO detectors of 4-8mm width, the computer simulation result of the system using wedge detectors reveals resolution improvement to the system using conventional detectors. For the system composed of 200 BGO detectors of 8mm width with 2 point sampling motion, the simulation resolution system using conventional detectors. For the very high resolution system of 3-7mm FWHM, the characteristics of the detector shape and size is studied by computer simulation.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.533-542
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• 2017

In diagnostic radiology, the imaging system has been changed from film/screen to digital system. However, the method for removing scatter radiation such as anti-scatter grid has not kept pace with this change. Therefore, authors have devised the indirect flat panel detector (FPD) system with net-like lead in substrate layer which can remove the scattered radiation. In clinical context, there are many radiographic examinations with angulated incident X-ray. However, our proposed FPD has net-like lead foil so the vertical lead foil to the angulate incident X-ray would have bad effect on its performance. In this study, we identified the effect of vertical/horizontal lead foil component on the novel system's performance and improved the structure of novel system for clinical usage with angulated incident X-ray. Grid exposure factor and image contrast were calculated to investigate various structure of novel system using Monte Carlo simulation software when the incident X-ray was tilted ($0^{\circ}$, $15^{\circ}$, and $30^{\circ}$ from the detector plane). More photons were needed to obtain same image quality in the novel system with vertical lead foil only then the system with horizontal lead foil only. An optimal structure of novel system having different heights of its vertical and horizontal lead foil component showed improved performance compared with the novel system in a previous study. Therefore, the novel system will be useful in a clinical context with the angulated incident X-ray if the height and direction of lead foil in the substrate layer are optimized as the condition of conventional radiography.

• Research in Community and Public Health Nursing
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• v.11 no.2
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• pp.538-555
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• 2000

The purpose of this study, in which 573 students from 2 high schools in Kang Nung city participated was to identify the attitude and experience of sexual harassment. This information will provide useful data, and promote a more systematic sexual harassment education program. The subjects of this study were 278 male students and 295 female students. The data was collected from September 25 to October 6. 2000. The data was analyzed using the statistical Computer package. SPSS to manipulate the data along with frequency, percentage, and mean t-test. The results from this study were summarized as follows. 1. The results from this comparison between two groups were significant in their attitude on sexual harassment(t=-2.26. p=0.024). Female students had higher scores than male students. 2. As a cause of sexual harassment. 'A man's misjudgement regarding a women as sexual objects(n=130: 22.7%)'. 'Patriarchal system of unequal distribution of power and status between the sexes(n=105: 18.3%)'. 'The effect of sexual stimulatives. (pornography. pornovideo. TV program ect.)(n=89: 15.5%)'. 3. As a countermeasure for prevention, 'Punishment, law and regulation of the sexual harasser(n = 151; 26.4%)', 'A preventive education of sexual harassment in adolescence (n = 125: 21.8%)'. 'Reformation of gender inequality and sex discrimination in the socio-structure(n=76; 13.3%)'. 4. Out of 573 students who participated in this study, 209(36.5%) students reported experiencing an incident of sexual harassment. For 278 males who participated in this study, 88(31.7%) had experienced an incident of sexual harassment. For the 295 females who participated in this study, 121(41.0%) had experienced an incident of sexual harassment. The type of sexual harassment is reported physical sexual harassment(n = 248: 40.5%), verbal sexual harassment(n = 226; 36.7%), and visual sexual harassment(n=139: 22.6%). 5. Their age in which they had experienced harassment was usually 'after 16 years of age(n=122: 58.4%)'. The age of harassers were mostly teenagers(n=112; 53.6%). The relationship to the with sexual harasser was a stranger (n=85; 40.7%), or a friend(n=78: 37.3%). After the incident of sexual harassment occurred, some students informed friends (n=114: 54.5%), 63(30.1%) told no one. Male students' feelings after the experienced harassment ranged from: 'be interesting', 'be pleasant'. Female students' feelings after the experienced harassment ranged from; 'be surprised', 'get a shock', 'fear', 'shame'.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1051-1058
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• 1998

We propose a bandpass filter using wavelength selectivity as variation of writing beam incident angle in photorefractive crystal. From TWM(Two-Wave Mixing) experiment, optimal diffraction properties are induced, and bandpass filter for selection wavelength transmission bandwidth are taken by change of writing beam incident angle.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.203-207
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• 2005

Objectives: Recently, the American Diabetes Association (ADA) redefined the criteria of prediabetes, which has lowered the diagnostic level of fasting plasma glucose (FPG) from 110 to 125 mg/dl, down to levels between 100 to 125mg/dl. The purpose of this study was to determine the predictive cutoff level of FPG as a risk for the development of diabetes mellitus in Korean men. Methods: A retrospective cohort study was conducted on 11,423 (64.5%) out of 17,696 males $\leq$30 years of age, and who met the FPG of $\leq$125 mg/dl and hemoglobin A1c of $\leq$ 6.4% criteria, without a history of diabetes, and who were enrolled at the screening center of a certain university hospital between January and December 1999. The subjects were followed from January 1999 to December 2002 (mean follow-up duration; 2.3(${\pm}0.7$) years). They were classified as normal (FPG <100mg/dl), high glucose (FPG $\geq$100mg/dl and <110mg/dl) and impaired fasting glucose (FPG $\geq$110mg/dl and $\leq$125mg/dl) on the basis of their fasting plasma glucose level measured in 1999. We compared the incidence of diabetes between the 3 groups by performing Cox proportional hazards model and used receiver operating characteristic analyses of the FPG level, in order to estimate the optimal cut-off values as predictors of incident diabetes. Results: At the baseline, most of the study subjects were in age in their 30s to 40s (mean age, 41.8(${\pm}7.1$) year). The incidence of diabetes mellitus in this study was 1.19 per 1,000 person-years (95% CI=0.68-1.79), which was much lower than the results of a community-based study that was 5.01 per 1,000 person-years. The relative risks of incident diabetes in the high glucose and impaired fasting glucose groups, compared with the normal glucose group, were 10.3 (95% CI=2.58-41.2) and 95.2 (95% CI= 29.3-309.1), respectively. After adjustment for age, body mass index, and log triglyceride, a FPG greater than 100mg/dl remained significant predictors of incident diabetes. Using the receiver operating characteristic (ROC) curve, the optimal cutoff level of FPG as a predictor of incident diabetes was 97.5 mg/dl, with a sensitivity and a specificity of 81.0% and 86.0%, respectively. Conclusion: These results suggest that lowering the criteria of impaired fasting glucose is needed in Korean male adults. Future studies on community-based populations, including women, will be required to determine the optimal cutoff level of FPG as a predictor of incident diabetes.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.3
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• pp.139-145
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• 1992

In this paper, a technique to separate the incident and reflected waves in the flume tests is investigated. Using a least squares method, the separation technique has been formulated systematically. This method is applicable to the regular and irregular wave conditions. To illustrate its validity and applicability, numerical experiments have been carried out for both regular and irregular wave conditions. It was found that the method gives perfect results for the conditions without signal noises, and yields reasonable results even for the conditions with 30% signal noises of incident wave height. Hydraulic experiments have been also performed to prove its applicability of the method for real situations.

• Journal of Veterinary Clinics
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• v.19 no.2
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• pp.153-158
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• 2002

Ovaries from total 192 slaughtered cows(154 Korean native cows and 38 Holstein cows) were collected during the slaughtering process in Kimhae, Changyoung and Yangsan abattoirs in Kyungnam province from January 2001 to January 2002. In order to investigate incidence of the ovarian cysts, anatomical, histological observations were performed and also TUNEL methods and PCNA antibody by immunogistochemical methods for diagnostic accuracy of cysts in a few ovaries were applied. Apoptotic positive cells by TUNEL method appeared not or a few in cystic walls but appeared more number in normal large follicular walls and the proliferative positive cells by PCNA antibody appeared numerous in normal large follicular walls but not or a few in cystic walls. The incident rates of ovarian cysts were 19.5% in Korean native cows and 18.4% in Holstein cows. The incident rates of ovarian cysts in Holstein cows were lower than that of Koran native cows. The incident rates of follicular cysts and luteal cysts in Korean native cows were 11.7% and 7.8% respectively. The incident rates of follicular cysts and luteal cysts in Holstein cows were 10.5% and 7.9%, respectively. Higher incidence proportions of ovarian cysts according to seasons in Korean native cows were ordered as spring (29.8%), autumn (21.4%) winter (14.3%) and summer (6.7%). Rates of cows with single cyst and multiple cysts were 63.3%(19 heads /30 heads) and 36.7%(11 heads/30 heads) in 30 cystic Korean native cows, respectively. Cystic cows with corpus luteums were 50.0%(15 heads) in 30 Korean native cows and 42.9%(3 heads) in 7 dairy cows, respectively. Among 15 cystic Korean native cows with corpus luteums, rates of cows with single corpus luteum were 66.7%(10 heads) and rates of multiple corpus luteum were 33.3%(5 heads ), respectively. The average diameter of cysts and corpus luteums in cystic ovaries were 21.0$\times$17.1 mm and 18.1$\times$13.8 mm in 30 Korean native cows and 20.6$\times$17.7 mm and 19.3 $\times$ 14.9 mm in 7 Holstein cows, respectively. So the average sizes of cysts in cystic ovaries were larger than those of corpus luteums.

• Korean Journal of Optics and Photonics
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• v.4 no.3
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• pp.323-329
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• 1993

In this paper, dependence of the diffraction efficiency upon incident light intensity is studied. The conductivity ratio, which is dependent upon the incident light intensity, changes the static electric field in a crystal. This change of the static electric field modulates the refractive index via linear electro-optic effect. And the change of the refractive index affects the diffraction efficiency. It is found that experimental results with $Fe:LiNbO_3$ crystals are in good agreement with the theory.