• Journal of the Korean Society of School Health
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• v.24 no.1
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• pp.99-109
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• 2011

Purpose: The purpose of this study was to investigate factors influencing dysmenorrhea in middle school girls and to analyze the differences in dysmenorrhea according to personal factors of the subjects. Methods: This study was conducted from March 22 to April 2, 2010. The subjects of the study were 572 girls who attended three middle schools in Seoul and experienced dysmenorrheal. All were surveyed using the same questionnaire. Data were analyzed by the SPSS/WIN 12.0 program and included descriptive statistics, ANOVA and multiple regression analysis. Results: 1) The mean age of the subjects was 13.53 years, and the mean age of first menstruation (menarche) was 11.94 years. The number of days between the onset of menstrual cycles was 30.01 days. Most of the respondents had irregular menstrual cycles and menstrual periods lasting 3 to 7 days long. 2) Chief menstrual pains were lower abdominal and back pain. Subjects reported experiencing severe lower abdominal and/or back pain, most commonly on the second day of menstruation. The average score of menstrual discomfort was over 60 points (63%). The average score per 6 points of dysmenorrhea was as follows: fatigue (3.48), sensitivity (3.27), disability of movement (3.27), napping or lying down (2.98), mood swings (2.95), interference with studies (2.87). 3) Individual subject characteristics influencing the onset of dysmenorrhea were as follows: high stress levels, being in poor health, having an irregular diet, being younger and having longer menstrual periods than most other subjects. Conclusion: During puberty, girls with earlier menarche complained of physical and emotional discomfort, and irregular menstrual periods. Therefore, we need to explain overall menstrual characteristics and individual differences in the occurrence of dysmenorrhea, in health education programs.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.48-53
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• 2012

Due to the customer needs of reducing cost and delivery date shorting, prompt change in the production plan became more important. In the multi period system (For instance, production line.) where target processing time exists, production, idle and delay risks occur repeatedly for multiple periods. In such situations, delay of one process may influence the delivery date of an entire process. In this paper, we discuss the minimum expected cost of the case mentioned above, where the risk depends on the previous situation and occurs repeatedly for multiple periods. This paper considers the optimal switching frequency to minimize the total expected cost of the production process. In this paper, first, the optimal switching frequency model is proposed. Next, the mathematic formulation of the total expectation is presented. Finally, the policy of optimal switching frequency is investigated by numerical experiments.

• The korean journal of orthodontics
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• v.43 no.3
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• pp.120-126
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• 2013

Objective: To gain basic information regarding the biologic stability of plasma ion-implanted miniscrews and their potential clinical applications. Methods: Sixteen plasma ion-implanted and 16 sandblasted and acid-etched (SLA) miniscrews were bilaterally inserted in the mandibles of 4 beagles (2 miniscrews of each type per quadrant). Then, 250 - 300 gm of force from Ni-Ti coil springs was applied for 2 different periods: 12 weeks on one side and 3 weeks contralaterally. Thereafter, the animals were sacrificed and mandibular specimens including the miniscrews were collected. The insertion torque and mobility were compared between the groups. The bone-implant contact and bone volume ratio were calculated within 800 mm of the miniscrews and compared between the loading periods. The number of osteoblasts was also quantified. The measurements were expressed as percentages and analyzed by independent t-tests (p < 0.05). Results: No significant differences in any of the analyzed parameters were noted between the groups. Conclusions: The preliminary findings indicate that plasma ion-implanted miniscrews have similar biologic characteristics to SLA miniscrews in terms of insertion torque, mobility, bone-implant contact rate, and bone volume rate.

• Animal cells and systems
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• v.11 no.1
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• pp.23-31
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• 2007

Programmed cell death was characterized in the silkworm thoracic ganglia TG1, TG2 and TG3 during postembryonic periods by TUNEL assay. Apoptotic cells were detected in the three TGs of all larval stages except for day-1, 2 1st instar larvae, in which no apoptotic cells were found. From day-7 5th larva, the numbers of apoptotic cells were dramatically increased and peaked on day-1 pupa and day-2 pupa and then abruptly decreased. Apoptotic cells finally disappeared in day-1 adult. In-vivo injection of 20-hydroxyecdysone (20E) into day-8 5th larva resulted in a striking decrease of apoptotic cells. Actinomycin D (Act D) or cycloheximide (CHX), injected into hemolymph of day-8 5th larva, resulted in a decrease of apoptotic cells in the three TGs. Injection of caspase-8 and -3 inhibitors also blocked cellular apoptosis. These results will provide valuable information for understanding of cellular changes in the three TGs during metamorphosis of the insect species.

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.10-16
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• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• Journal of Korean Society of Rural Planning
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• v.10 no.2 s.23
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• pp.25-34
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• 2004

The objectives of this study were to compare rural development of Korea and EU. According to its traits the peroids of rural development of Korea can be divided into low periods. According to its memberships and traits the periods of rural development of EU can be divided into low periods. There are many similarities between Korea and EU in agricultural situation and rural development. EU introduced multifunctionality of agriculture in 1980s and adopt strong policy to support that in 1990s. And EU made a effort sustainable rural development, integrated rural development and balanced regional development. Recently Korea not only maintain agricultural expanisionism but also pay attention to multifunctionality of agriculture. But rural development of Korea still in the stage of physical planning and agricultural expanisionism. So it leaves much room for improvement to rural development of Korea in rural development regulation, unifying theme, detail planning, integration among policies, balanced regional development, etc.

• Industrial Engineering and Management Systems
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• v.12 no.2
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• pp.95-102
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• 2013

It is difficult to determine an appropriate discount price for daily perishable products to increase profit from a long-term standpoint. Even if the discount pricing is efficient to increase profit of the day, consumers memorize the sales price and they might hesitate to purchase the product at a regular price the following day. The authors discussed the inventory clearance pricing for a single period in our previous study by constructing a mathematical model to derive an optimal sales price to maximize the expected profit by considering the reference price effect of demand. This paper extends the discussion to handle the discount pricing for multiple periods. A mathematical analysis is first conducted to reveal the properties on an objective function, which is the present value of total expected profits for multiple periods. An algorithm is then proposed to derive an optimal price for asymmetric consumers. Numerical experiments investigate the characteristics of the objective function and optimal pricings.

• The Plant Pathology Journal
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• v.32 no.1
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• pp.1-7
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• 2016

Responses of Botryosphaeria dothidea to interrupted wetness periods were investigated under in vivo and in vitro conditions. Conidia of B. dothidea were allowed to germinate on apple fruits under wetting condition at $25^{\circ}C$ for 5 hr. They were air-dried for 0, 1, 2 or 4 hr, and then rewetted at $25^{\circ}C$ for 5 hr. Following an initial wetness period of 5 hr, 83% of the conidia germinated. The percent conidial germination increased to 96% when wetting was extended continuously another 5 hr. However, no further conidial germination was observed when wetting was interrupted by dry periods of 1, 2 and 4 hr, resulting in 83, 81 and 82%, respectively. The mean length of the germ tubes was $37{\mu}m$ after 5 hr of wetting and elongated to $157{\mu}m$ after 10 hr of continuous wetting. On the other hand, interruption of wetting by a dry period of 1 hr or longer after the 5 hr of initial wetting arrested the germ tube elongation at approximately $42{\mu}m$ long. Prolonged rewetting up to 40 hr did not restore germ tube elongation on slide glasses under substrate treatments. Model simulation using weather data sets revealed that ending infection periods by a dry period of at least 1 hr decreased the daily infection periods, avoiding the overestimation of infection warning. This information can be incorporated into infection models for scheduling fungicide sprays to control apple white rot with fewer fungicide applications.

• Journal of Environmental Science International
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• v.25 no.10
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• pp.1369-1379
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• 2016

This research assessed the disparity in anion generation according to the vertical structure of a Zelkova Serrata tree for the purpose of creating a pleasant and green city environment. Measurements for the study were conducted between July and August of 2014 in Chung-ju in the central region of the Republic of Korea. The average anion generation of vertical structure trees during active photosynthesis periods was: L Section ($839.0ea/cm^3$) > M Section ($664.6ea/cm^3$) > U Section ($472.0ea/cm^3$). According to DMRT analysis, significant difference was found in the average between the L, or M Locations and the U Locations. During dormant photosynthesis periods, records showed that the anion production at the M Location ($1,212.5ea/cm^3$) > L Location ($1,050.4ea/cm^3$) > H Location ($844.1ea/cm^3$), According to DMRT analysis, the difference within each location was significant for ${\alpha}=0.05$. In a comprehensive analysis of the weather factors in each vertical structure, anion generation during active photosynthesis periods showed a positive correlation with solar radiation and a negative correlation with wind speed. Dormant photosynthesis periods showed negative correlations with both solar radiation and temperature, and positive correlations with relative humidity and wind speed. Predictions from a multicenter retrospective study showed that during active photosynthesis periods, $Y_1=282.443X_1+512.07$, and $Y_2=314.337X_1+16.913X_2$, while during dormant photosynthesis periods, $Y_1=391.009X_1+840.043$, and $Y_2=351.412X_1+32.765X_2$.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.104-108
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• 2018

Experimental studies have been done to examine the aging characteristics by regulator diaphragms of gas pressure, governor room of city gas. Various testing samples with different service periods were manufactured. The results of SEM observation indicated that the surface and thickness of the samples tested were slightly sensitive to the service periods. It was found that as the service periods increased, the tensile strength of diaphragm samples decreased. For samples over 25 years of service, the strength decreased to approximately 60 % of that of new diaphragms. It was also found that as the service periods increased, the elongation increased.