• Journal of Ocean Engineering and Technology
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• v.25 no.2
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• pp.120-126
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• 2011

The fatigue damages in structural details of offshore plants can be accumulated due to various environmental loadings such as swell, wave, wind and current. It is known that load histories acting on mooring and riser systems show stationary and ergodic bimodal wide-banded process. This paper provides refined approach to obtain time signals representing stress range histories from wide-banded bimodal spectrum which consists of ideally narrow-banded and fully separated two spectrums. Variations of the probabilistic characteristics for time signals according to frequency and sampling time increments are compared with the reference data to be the probabilistic characteristics such as zero-crossing period, peak period, and irregularity factor obtained from an assumed ideal spectrum. It is proved that the sampling time increment more affects on the probabilistic characteristics than frequency increment. The fatigue damages according to the frequency and sampling time increments are also compared with the ones with minimum increment condition which are thought to be exact fatigue damage. It is concluded that the maximum sampling time increment to obtain reliable time signals should be determined that ratio of applied maximum sampling time increment and minimum period is less than approximately 0.08.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.29-38
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• 2015

In this study, track dynamic interaction characteristics caused by the vehicle running through transitional section such as bridge abutments were studied using the finite element analysis program. The geometric condition of track was generated by trigonometric function and allowable maximum track irregularity is determined by KORAIL track maintenance criteria. The sub-infrastructure under rail fastener system was modelled by 3D solid elements. To reduce computational cost only half track line is numerically considered and the roller boundary condition was applied to each side of model. In this study, the vehicle-track dynamic interaction analysis was carried out for standard Korean transition section of concrete track and the dynamic behaviors were investigated. The dynamic characteristics considered are wheel load variation, vertical acceleration at body, and maximum Mises stress at each part of transitional section.

• The korean journal of orthodontics
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• v.47 no.1
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• pp.11-20
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• 2017

Objective: This randomized controlled trial aimed to compare the stability of mandibular arch orthodontic treatment outcomes between passive self-ligating and conventional systems during 6 months of retention. Methods: Forty-seven orthodontic patients with mild to moderate crowding malocclusions not requiring extraction were recruited based on inclusion criteria. Patients (mean age $21.58{\pm}2.94years$) were randomized into two groups to receive either passive self-ligating ($Damon^{(R)}$ 3MX, n = 23) or conventional system (Gemini MBT, n = 24) orthodontic treatment. Direct measurements of the final sample comprising 20 study models per group were performed using a digital caliper at the debonding stage, and 1 month, 3 months, and 6 months after debonding. Paired t-test, independent t-test, and non-parametric test were used for statistical analysis. Results: A significant increase (p < 0.01) in incisor irregularity was observed in both self-ligating and conventional system groups. A significant reduction (p < 0.01) in second interpremolar width was observed in both groups. Mandibular arch length decreased significantly (p = 0.001) in the conventional system group but not in the self-ligating system group. A similar pattern of stability was observed for intercanine width, first interpremolar width, intermolar width, and arch depth throughout the 6-month retention period after debonding. Comparison of incisor irregularity and arch dimension changes between self-ligating system and conventional system groups during the 6 months were non-significant. Conclusions: The stability of treatment outcomes for mild to moderate crowding malocclusions was similar between the self-ligating system and conventional system during the first 6 months of retention.

• Journal of KIISE
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• v.44 no.10
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• pp.1094-1104
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• 2017

In this paper, a motion image is detected based on the irregularity of lights. This motion image is extracted by modifying the reflected light region of the 3 way-diff algorithms. 3 way-diff algorithm extracts reflected light region using the 3-successive image. In this algorithm, The reflected light region is a region generated by light in the image production process and is finally created around all objects. The algorithm shows a process to extracting the region. This process is a simple operation, but doesn't have a defined formula for light. This paper judges that the reflected light region is a kind of noise at the 3 way-diff algorithms and defines the formula for extracting the reflected light region. It shows that compared with the proposed algorithm and existing algorithm through experiment.

• The Korean Journal of Community Living Science
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• v.17 no.3
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• pp.99-107
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• 2006

This study was performed to investigate the dietary habit based on residence types of male college students who registered nutrition course for nonmajor. Self reports on dietary habit and one-day dietary records were obtained from 158 male college students in Chungbuk area. The distribution of residence type of male college student was as follows; self-boarding(43.0%), home(41.1%), boarding with meal(12.7%), and others(3.2%). The mean age of subjects were $22.6{\pm}2.5$, and the mean height and weight were $175.0{\pm}5.6cm\;and\;69.1{\pm}9.3kg$, respectively. The dietary habit of male college students considered to be taken more care of, showing indifference to dietary balance, irregularity of meal, and skipping breakfast. One-day dietary records by 24hr recall methods also showed less diverse food intake(mean DVS, 12.7; mean DDS, 3.92). Especially, the students with self boarding residence were more likely not to eat properly, including indifference to dietary balance, irregularity of meal, skipping breakfast, frequent dining-out, high experience of smoking and drinking, and low DVS and DDS. Also the students with self boarding residence seemed not to make a good choice for food, showing high food intake frequency score in canned food, fast food and instant ramyun, while low score in fruit and fishes. More attention should be taken for self-boarding students to recognize the problems in their own dietary behavior, and more practical suggestion to improve their dietary status would be necessary.

• Women's Health Nursing
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• v.26 no.3
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• pp.231-239
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• 2020

Purpose: The purpose of this study was to investigate factors affecting premenstrual symptoms among nursing students, focusing on depression, fatigue, and body esteem. Methods: The participants were 145 nursing students at a university located in Changwon, Korea. Data were collected from November 2 to November 30, 2019 using self-reported structured questionnaires, and analyzed using descriptive statistics, independent t-test, analysis of variance, Pearson correlation coefficients, and multiple regression analysis. Results: The mean item score for premenstrual symptoms was 2.52±0.92, indicating a low level. The mean score for depression was 16.05±7.72, and 15.2% of participants were found to be moderately depressed and 9.7% severely depressed. The mean item score for fatigue was 4.84±0.84, indicating a moderate level, and body esteem was 2.94±0.44, indicating a moderate level. The premenstrual symptoms of nursing students showed a statistically significant correlation with depression (r=-.58, p<.001), fatigue (r=.33, p<.001), and body esteem (r=-.28, p<.001). Factors impacting premenstrual symptoms of nursing students were depression (β=.47, p<.001), dysmenorrhea (β=-.18, p=.009), menstrual cycle irregularity (β=.17, p=.013), and body esteem (β=-.14, p=.038). The total explanatory power of these variables was 41.0%. Conclusion: Findings from this sample of nursing students suggest that intervention programs to relieve premenstrual symptoms should focus on depression, menstrual cycle irregularity, dysmenorrhea, and body esteem.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.70-77
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• 1999

An extremely cadmium-tolerant budding yeast, Hansenula anomala B-7 underwent a morphological switch in response to either heat shock treatment or cadmium stress, respectively. It exhibited a morphological transition from a unicellular yeast form to a pseudohyphae-like coagulation when subjected to prolonged heat shock treatment. In contrast, the yeast cells showed an irregularity in surface morphology when given thermal stress for a short time. Patterns of proteins expressed in the pseudohyphae-like cells demonstrated that several proteins were overexpressed while others were underexpressed in comparison with those prepared from the cells in the yeast form. It was a striking feature, however, that nearly 40％ of the proteins extracted from the cells in the pseudohyphae form appeared to be composed of a single polypeptide. This polypeptide was apparently overexpressed during the pseudohyphae phase and its molecular weight was estimated to be 58 kDa according to SDS-PAGE analysis. However, a significant level of the protein was not observed in the cells before transition to pseudohyphae. The architecture of the cell shape was also damaged when incubated in a medium containing more than 1,000 ppm (8.9mM) of cadmium ions, although able to proliferate at a slow rate. However, the irregularity in the cell morphology exerted either by the brief heat shock treatment or by the cadmium stress with the high concentrations of the metal ions was not repaired, even though the damaged cells were allowed to grow for sufficient time in fresh, cadmium-free medium.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.139-149
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• 1999

In this paper, we estimate the scale factor error and random walk characteristics of the ring laser gyro which has the body dither for Lock-in compensation. And then, we compared those results with the static test results for 28cm square ring laser gyro which has about 0.5 deg/sec static Lock-in. In the case of sinusoidal body dither, dynamic Lock-in occurs periodically at the points where the gyro output pulse becomes the integer multiples of body dither frequency. The width of dynamic Lock-in is changed by variation of dither amplitude, and, between the width of dynamic Lock-in which occurs at the even multiple points of body dither frequency and that at the odd muliple points of body dither frequency, it has 180o phase difference. Generally random body dither is adopted to compensate for dynamic Lock-in. Then if the irregularity is not large enough, the scale factor error by dynamic Lock-in is not vanished. And if the irregularity is large enough, the scale factor error decreases, but random walk becomes larger relatively. And we confirmed that the larger body dither amplitude, the smaller random walk.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.169-174
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• 2014

Practical deployment methods for sensor nodes are demanding as applications using sensor nodes increase. In particular, node connectivity is crucial not only for the network longevity but also for direct impacts on sensing and data collection capability. Economic requirement at building sensor networks and often limited access for sensor fields due to hostile environment force to remain at random deployment from air. However, random deployment often result in lost connection problem and inefficient network topology issue due to node irregularity. In this paper, mixed deployment of key nodes that have better communication capability is proposed to support the original deployment into working in an efficient way. Node irregularity is improved by introducing mixed nodes and an efficient mixed node density is also analyzed. Simulation results show that the mixed deployment method has better performance than the existing deployment methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1643-1646
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• 2003

Drawing is a mechanical operation that attenuates thick material to an appropriate thickness for the next processing or end usage. When the input material has the form of a bundle or bundles made of very thin and long shaped wire or fibers, this attenuation operation is called "bundle drawing" or "drafting" Drafting is being used widely in manufacturing staple yarns. which is indispensable for the textile industry. However, the bundle processed by this operation undertake more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. Since long there have been many researches tying to find out factors affecting the irregularity of linear desity, to obtain optimal drafting conditions, to develop efficient measuring and analysis methods of linear density of bundle, etc., but there exists yet no fundamental equation describing the dynamic behavior of the flowing bundle during processing. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical lows representing physical variables, i.e. linear density and velocity as the dynamic state of bundle. The conservation of mass and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.