• Title/Summary/Keyword: Wake Control

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Reaction Force Analysis on the Journal Bearing of Shafting System with Contra-Rotating Propeller (상반회전 프로펠러 축계 저널 베어링 반력해석)

  • Shin, Sang-Hoon;Lee, Seung-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.10
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    • pp.270-276
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    • 2019
  • According to the International Maritime Organization (IMO) 2020 Regulation, ships operating outside designated emission control areas (ECA) have to use low-sulfur oil with a sulfur content of 0.5% or less by January 2020. To minimize the consumption of high-priced low-sulfur oil, it is urgent to introduce efficient energy-saving devices (ESD), and contra-rotating propeller (CRP) systems are well known to be the most effective one. The shafting system that drives a CRP is composed of an inner shaft and an outer one and has a mutually influential system that is much more complex and heavier than a general shafting system. An initial design was carried out to install a CRP system for the first time in Korea. The purpose of this study is to verify whether the journal bearing meets the classification's design criteria through a bearing reaction force analysis for the classification's approval of the initial design. It is ideal for the thrust of the propeller to act on the center of the shaft, but thrust eccentricity occurs due to the uneven wake caused by the stern shape. Load conditions were applied while considering thrust eccentricity to perform the shaft analysis, and the results were compared with the classification's criteria.

The Effects of Modafinil on Clinical Features and Sleep Structure of Narcolepsy Patients and Healthy Controls (모다피닐이 기면병 환자와 대조군의 임상 양상과 수면구조에 구조에 미치는 영향)

  • Shin, Hong-Beom;Jeong, Do-Un;Kim, Eui-Joong
    • Sleep Medicine and Psychophysiology
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    • v.13 no.2
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    • pp.67-74
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    • 2006
  • Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

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Derivation of Nacelle Transfer Function Using LiDAR Measurement (라이다(LiDAR) 측정을 이용한 나셀전달함수의 유도)

  • Kim, Hyun-Goo;Kang, Yong-Heack;Yun, Chang-Yeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.9
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    • pp.929-936
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    • 2015
  • Nacelle anemometers are mounted on wind-turbine nacelles behind blade roots to measure the free-stream wind speed projected onto the wind turbine for control purposes. However, nacelle anemometers measure the transformed wind speed that is due to the wake effect caused by the blades' rotation and the nacelle geometry, etc. In this paper, we derive the Nacelle Transfer Function (NTF) to calibrate the nacelle wind speed to the free-stream wind speed, as required to carry out the performance test of wind turbines according to the IEC 61400-12-2 Wind-Turbine Standard. For the reference free-stream wind data, we use the Light Detection And Ranging (LiDAR) measurement at the Shinan wind power plant located on the Bigeumdo Island shoreline. To improve the simple linear regression NTF, we derive the multiple nonlinear regression NTF. The standard error of the wind speed was found to have decreased by a factor of 9.4, whereas the mean of the power-output residual distribution decreased by 6.5 when the 2-parameter NTF was used instead of the 1-parameter NTF.

A Consensus Plan for Action to Improve Access to Cancer Care in the Association of Southeast Asian Nations (ASEAN) Region

  • Woodward, Mark
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.19
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    • pp.8521-8526
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    • 2014
  • In many countries of the Association of Southeast Asian Nations (ASEAN), cancer is an increasing problem due to ageing and a transition to Western lifestyles. Governments have been slow to react to the health consequences of these socioeconomic changes, leading to the risk of a cancer epidemic overwhelming the region. A major limitation to motivating change is the paucity of high-quality data on cancer, and its socioeconomic repercussions, in ASEAN. Two initiatives have been launched to address these issues. First, a study of over 9000 new cancer patients in ASEAN - the ACTION study - which records information on financial difficulties, as well as clinical outcomes, subsequent to the diagnosis. Second, a series of roundtable meetings of key stakeholders and experts, with the broad aim of producing advice for governments in ASEAN to take appropriate account of issues relating to cancer, as well as to generate knowledge and interest through engagement with the media. An important product of these roundtables has been the Jakarta Call to Action on Cancer Control. The growth and ageing of populations is a global challenge for cancer services. In the less developed parts of Asia, and elsewhere, these problems are compounded by the epidemiological transition to Western lifestyles and lack of awareness of cancer at the government level. For many years, health services in less developed countries have concentrated on infectious diseases and mother-and-child health; despite a recent wake-up call (United Nations, 2010), these health services have so far failed to allow for the huge increase in cancer cases to come. It has been estimated that, in Asia, the number of new cancer cases per year will grow from 6.1 million in 2008 to 10.6 million in 2030 (Sankaranarayanan et al., 2014). In the countries of the Association of Southeast Asian Nations (ASEAN), corresponding figures are 770 thousand in 2012 (Figure 1), rising to 1.3 million in 2030 (Ferlay et al., 2012). ASEAN consists of Brunei Darussalam, Cambodia, Indonesia, Lao, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Viet Nam. It, thus, includes low- and middle-income countries where the double whammy of infectious and chronic diseases will pose an enormous challenge in allocating limited resources to competing health issues. Cancer statistics, even at the sub-national level, only tell part of the story. Many individuals who contract cancer in poor countries have no medical insurance and no, or limited, expectation of public assistance. Whilst any person who has a family member with cancer can expect to bear some consequential burden of care or expense, in a poor family in a poor environment the burden will surely be greater. This additional burden from cancer is rarely considered, and even more rarely quantified, even in developed nations.

The Comparison of Various Turbulence Models of the Flow around a Wall Mounted Square Cylinder (벽면에 부착된 사각 실린더 주변 유동에 대한 난류모델 비교연구)

  • Bae, Jun-Young;Song, Gi-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.4
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    • pp.419-428
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    • 2020
  • The flow past a wall mounted square cylinder, a typical and basic shape of building, bridge or offshore structure, was simulated using URANS computation through adoption of three turbulence models, namely, the k-ε model, k-ω model, and the v2-f model. It is well known that this flow is naturally unstable due to the Karman vortex shedding and exhibits a complex flow structure in the wake region. The mean flow field including velocity profiles and the dominant frequency of flow oscillation that was from the simulations discussed earlier were compared with the experimental data observed by Wang et al. (2004; 2006). Based on these comparisons it was found that the v2-f model is most accurate for the URANS simulation; moreover, the k-ω model is also acceptable. However, the k-ε model was found to be unsuitable in this case. Therefore, v2-f model is proved to be an excellent choice for the analysis of flow with massive separation. Therefore, it is expected to be used in future by studies aiming to control the flow separation.

Current Status and Future Prospects of the Population Control Policy in Korea (출산조절정책의 현황과 전망)

  • 조남훈
    • Korea journal of population studies
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    • v.11 no.1
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    • pp.14-31
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    • 1988
  • The national family planning program in Korea, which was instituted as an integral part of the nation's economic development plans since 1962, has contributed greatly to a reduction in the fertility and population growth rate. The total fertility rate dipped from 6.0 births per women in 1960 to 2.0 in 1985, and the population growth rate rom 2.84 percent per year to 1.25 percent during the same period, while the contraceptive practice rate for the 15-44 married women increased from 9 percent in 1965 to 70 percent in 1985. Study findings indicate that the fertility reduction in the past 26 years is largely attributed to the virgorous implementation of the national family planning program, rising age at marriage, wide-spread use of induced abortion, and the changes in attitude regarding the value of children that came into being in the wake of the rapid socio-economic development over the period. Among the strengths of the national family planning program are the following : 1) a pluralistic system of program manageent with active participation of various government and voluntary organizations, 2) utilization of a large corps of family planning field workers to conduct face-to-face communication and motivation activities, 3) use of private physicians with government support to provide contraceptive services, 4) a systematic program management system including program planning of traget allocation, evaluation, and supervision with a broad MIS and award system, 5) numerous incentive and disincentive schemes for stimulating the small family norm and contraceptive use, and 6) strong commitments to the family planning program by political leaders. The new demographic targets during the Sixth Five-Year Economic and Social Development plan period(1987-91) have been set for a further reduction in the population growth rate to 1.0 percent by 1993, assuming that the TFR will decline to 1.75 level in 1995. This target is, however, not easy to achieve due to anticipated unfavorable factors like the strong boy preference, high discontinuation rates of reversible contraceptive methods, fertility termination-oriented contraceptive use, a plateau level of contraceptive practice rate that has mostly accounted for a sterilization, shortened length of birth intervals, and the changing patterns of contraceptive mix. The recent changes in contraceptive and fertility behaviors clearly indicate that the past quantity-oriented management system of the national program should be redirected toward a quality-oriented approach. Particularly, program efforts should be expanded to recruit new contraceptive users in the 20s of younger age groups, both for birth spacing and controlling their fertility since the women aged 20 to 29 account for more than 80 percent of the total annual births in recent years. In addition, the current contraceptive fee system of the national family planning program should be gradually shifted from free contraceptive services to a acceptor's charge system, and the provision of contraceptive services through the medical insurance system, which will cover the entire population by 1989, should be accelerated as a means of integration of family planning program with other health programs.

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Evaluation of Autonomic Neuropathy in Patients with Sleep Apnea Syndrome (수면 무호흡 증후군 환자에서 자율 신경 장애의 평가)

  • Lee, Hak-Jun;Park, Hye-Jung;Shin, Chang-Jin;Kim, Ki-Beom;Chung, Jin-Hong;Lee, Kwan-Ho;Lee, Hyun-Woo
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.2
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    • pp.404-415
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    • 1998
  • Background: Sleep apnea syndrome, which occurs in 1~4 % of the adult population, frequently has different cardiovascular complications such as hypertension, ischemic heart disease, cardiac arrythmia as well as sleep-wake disorder such as excessive daytime hypersomnolence or insomnia. Mortality and vascular morbidity are reported to be significantly higher in sleep apnea syndrome patients than in normal population. According to the recent studies, autonomic dysfunction as well as hypoxemia, hypercapneic acidosis, and increased respiratory effort, may playa role in the high prevalence of cardiovascular complications in patients with sleep apnea syndrome. However the cause and mechanism of autonomic neuropathy in patients with sleep apnea syndrome are not well understood. We studied the existence of autonomic neuropathy in patients with sleep apnea syndrome and factors which influence the pathogenesis of autonomic neuropathy. Method: We used the cardiovascular autonomic neuropathy(CAN) test as a method for evaluation of autonomic neuropathy. The subjects of this study were 20 patients who diagnosed sleep apnea syndrome by polysomnography and 15 persons who were normal by polysomnography. Results: Body mass index and resting systolic blood pressure were higher in sleep apnea group than control group. Apnea index(Al), respiratory disturbance index(RDI) and snoring time percentage were significantly higher in sleep apnea group compared with control group. But there were no significant differences in saturation of oxygen and sleep efficiency in two groups. In the cardiac autonomic neuropathy test, the valsalva ratio was significantly low in sleep apnea group compared with control group but other tests had no differences between two groups. The CAN scores and corrected QT(QTc) interval were calculated significantly higher in sleep apnea group, but there were no significant correlations between CAN scores and QTc interval. There were no significant data of polysomnography to correlate to the CAN score. It meant that the autonomic neuropathy in patients with sleep apnea was affected by other multiple factors. Conclusion: The cardiovascular autonomic neuropathy test was a useful method for the evaluation of autonomic neuropathy in patients with sleep apnea syndrome and abnormalities of cardiovascular autonomic neuropathy were observed in patients with sleep apnea syndrome. However, we failed to define the factors that influence the pathogenesis of autonomic neuropathy of sleep apnea syndrome. This study warrants futher investigations in order to define the pathogenesis of autonomic neuropathy in patients with sleep apnea syndrome.

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Association between breakfast and lifestyle, interest in beauty care, and attitude toward breakfast in high school girls in Incheon (여고생의 아침식사와 라이프스타일, 외모 가꾸기 관심도 및 아침식사관련 태도의 관련성)

  • Lee, Seolmi;Kim, Mi-Hyun
    • Journal of Nutrition and Health
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    • v.53 no.3
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    • pp.288-302
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    • 2020
  • Purpose: This study examined the factors related to skipping breakfast in high school girls. Methods: A survey of a total of 581 high school girls residing in Incheon was conducted. The subjects were classified into 2 groups according to the breakfast frequency: "breakfast skipping" group (eating breakfast ≤ 2 times/week, n = 250) and "breakfast eating" group (eating breakfast ≥ 3 times/week, n = 331). This study compared the general characteristics, lifestyles, interest in weight control and beauty care, food habits, the reasons and symptoms of skipping breakfast, as well as the attitude toward breakfast between the 2 groups. Results: The mean age of the subjects was 16.5 years old. Approximately, 33.9%, 33.6%, and 32.5% of the subjects were in first grade, second grade, and third grade, respectively, with no significant difference between the 2 groups. The breakfast skipping group showed a high interest in weight control, and beauty care than the breakfast eating group. The breakfast skipping group consumed more afternoon snacks and late-night snacks, and ate dinner irregularly. Although the breakfast skipping group experienced the negative effects of skipping breakfast, they showed low recognition for the importance or role of breakfast. The most common reason for skipping breakfast was lack of time, which appears to be related to the late wake-up time and the time spent on make-up or beauty-care. Conclusion: Skipping breakfast by high school girls was related to a high interest in beauty care, irregular meals and low attitude toward the importance of breakfast for health and nutrition. Therefore, it is necessary to conduct nutrition education to change the perceptions and attitudes of female adolescents regarding the importance of breakfast by recognizing that breakfast can affect not only balanced nutrition and health, but also healthy physical beauty.

Historical Review on the Security Service for the Royal Household in the "Goryeo" Era (고려시대 왕실호위제도의 사적 고찰)

  • Lee, Sung-Jin;Kim, Eui-Young;Lee, Jong-Hwan
    • Korean Security Journal
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    • no.14
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    • pp.413-429
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    • 2007
  • The Guard over the royal household in the "Goryeo" era was the same as if was over the President or Ruler of a nation today. In those days, a king represented a nation and any threat to the safety of a king could bring the destruction of a nation and the dispersion of the people. by reviewing the change of the 2-Gun 6-Wi system of the era, it can be, summed up as follow, Ther will be suggestions. The Guard might focus on a king's personal safety in the wake of the system of the Silla and Taebong dynasties until the establishment of the Goryeo Dynasty's unique political system. "Goryeo" rebuilt the royal palace in Gyeonyeong-gun to take the shape of unified country after its accomplishment of unification of the late three countries, Then it was afraid of the rebellion and uprising of local powerful clans, The country put them under control and organized the local army with them in the era of Kings, Seongjong, through the kings, Seongjong and Gwangjong. The army system of "Goryeo" consisted of 2-Gun and 6-Wi, and 2-Gun placed above the 6-Wi played the role of the Royal guards, and among the organizations a certain army under the specific name of "Gyeonyong-gun" guarded the kings in the nearest position. An aristocratic culture enjoyed its golden age in the period of stability of the aristocracy of "Goryeo", but afterward in the confusion of the aristocratic disruption and incompatible confrontation the country lost its control, and faced military rebellions by treating civil officials well and ill-treating military officials The safety of kings become unstable with the grasping political power by the military officials, and "Dobang" was established in the era of Choi's family to grasp political power. In the era of Choi Woo, he gathered his men and organized his familys army with them and managed the personnel administration with the civil officials of "Jeongbang and Seobang under his command. Such a fact shows the similarity to today's task of guarding. Considering the facts that "Sambyeolcho, the military ground of the military-men-rule, was at the center of the struggling against Mongolia and that even after the fall of the military regime, they rebelled and fought against Mongolia to the end, we came to know that the nationalism in the era of the military era was great. In the transition of external situations from "Myeong" to "Won"(Chinese dynasties), the conflict between the old "Won"-friendly power and the new "Myeong"-friendly power caused the weakness of the power to guard the royal household, and "Goryeo" at last gave way to the newly rising "Joseon" led by Lee, Seong Gye who won the people's confidence.

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The current status and control measures of BSE in the worldwide (국내, 외 광우병의 발생 현황과 대응 방안)

  • Yoo, Han-Sang
    • 한국환경농학회:학술대회논문집
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    • 2009.07a
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    • pp.273-282
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    • 2009
  • The transmissible spongiform encephalopathies (TSEs) disease group are fatal neurodegenerative disorders affecting a wide range of hosts. The group includes kuru and Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep and goats and Bovine spongiform encephalopathy (BSE) in cattle. The exact nature of the infectious agent involved in the transmission of these diseases remains controversial. However, a central event in their pathogenesis is the accumulation in infected tissues of an abnormal form of a host-encoded protein, the prion protein (PrP). Whereas the normal cellular protein is fully sensitive to protease ($PrP^{sen}$), the disease-associated prion protein ($PrP^d$) is only partly degraded ($PrP^{res}$), its amino-terminal end being removed. BSE was first reported in the mid-80s in the UK. Ten years later, a new form of human prion disease, variant CJD (vCJD) developed in the wake of the BSE epidemic, and there is now strong scientific evidence that vCJD was initiated by the exposure of humans to BSE-infected tissues, thus indicating a zoonotic disease. However, the ban on the feeding of animal-derived proteins to ruminants, and the apparent lack of vertical transmission of BSE, have led to a decline in the incidence of the disease within cattle herd and therefore, an assumed decreased risk for human contacting vCJD. The origin of the original case(s) of BSE still remains an enigma even though three hypotheses have been raised. Hypotheses are i) sheep- or goat-derived scrapie-infected tissues included in meat and bone meal fed to cattle, ii) a previously undetected sporadic or genetic bovine TSE contaminating cattle feed or iii) originating from a human TSE through animal feed contaminated with human remains. A host cellular membrane protein ($PrP^C$), which is abundant in central nervous system tissue, appear to be conformationally altered in the diseased host into a prion protein ($PrP^{Sc}$). This $PrP^{Sc}$ is detergent insoluble and partially protease-resistant ($PrP^{res}$). The term $PrP^{res}$ is normally used to describe the protein detected after protease treatment, in techniques such as Western immunoblotting, and enzyme-linked immunosorbant assay using fresh/frozen tissue. Immunohistochemistry may performed with formalin-fixed tissues. Also, clinical signs of the BSE are one of the major diagnostic indicators. Recently, atypical forms (known as H- and L-type) of BSE have appeared in several European countries, Japan, Canada and the United States. An unusual case was also reported in a miniature zebu. The atypical BSE fall into two groups based on the relative molecular mass (Mm) of the unglycosylated $PrP^{res}$ band relative to that of classical BSE, one of the higher Mm (H-type) and the other lower (L-type). Both types have been detected worldwide as rare cases in older animals, at a low prevalence consistent with the possibility of sporadic forms of prion diseases in cattle. This raises the unwelcome possibility that vCJD could increase in the human population. Now, active surveillance program against BSE is going on in Korea. In regional veterinary service lab, ELISA is applied to screen the BSE in slaughter and confirmatory tests by Western immunoblotting and immunohistochemisty are carried out if there are positive or suspect in the screening test. Also, the ruminant feed ban is rigorously enforced. Removal of specified risk materials such as brain and spinal cord from cattle is mandatory process at slaughter to prevent the infected material from entering the human food chain.

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