• Title/Summary/Keyword: Periodic Review

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Fourier Transformations (TEM 관련 이론해설 (2): Fourier 변환)

  • Lee, Hwack-Joo
    • Applied Microscopy
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    • v.32 no.3
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    • pp.195-204
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    • 2002
  • In this review, the fundamental concepts of delta function, convolution integral and Fourier transformation are discussed. The applications of Fourier transformation to slit function, two very narrow slits, two slits of appreciable width, periodic array of narrow slits, arbitary periodic function, diffraction gratings and gaussian functions are also introduced.

CURRENT STATUS AND PROSPECT FOR PERIODIC SAFETY REVIEW OF AGING NUCLEAR POWER PLANTS IN KOREA

  • Jin, Tae-Eun;Roh, Heui-Young;Kim, Tae-Ryong;Park, Young-Sheop
    • Nuclear Engineering and Technology
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    • v.41 no.4
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    • pp.545-548
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    • 2009
  • Korean utility has utilized a Periodic Safety Review (PSR) that assesses the cumulative effects of plant aging, modifications, operating experience, technical developments, and site characteristics since 2000. In particular, the assessment and management of plant aging is one of the major areas in PSR. It includes identification of critical Systems, Structures, and Components (SSCs) for aging, assessment of aging effects, and implementation of aging management programs. Since the PSR system was introduced based on the atomic energy acts and related laws, PSRs of eight sets for 12 Nuclear Power Plants (NPPs) that have been operating more than 10 years have been completed. PSRs of two sets for 4 NPPs are currently being carried out. The utility has confirmed that domestic NPPs have been operated safely through these PSRs and have implemented the follow-up corrective activities to increase the nuclear safety. In this paper, the status of PSR implementation is discussed and improvement programs to conduct PSR follow-up corrective activities efficiently for NPPs are suggested based on experiences with aging assessments.

A Study on the Clinical Study of Periodic Treatment of Endometriosis (자궁내막증의 주기요법 임상 연구에 대한 고찰)

  • Park, Jang-Kyung
    • The Journal of Korean Obstetrics and Gynecology
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    • v.33 no.2
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    • pp.112-123
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    • 2020
  • Objectives: The purpose of this study is to review the research in the cyclic treatment of endometriosis in traditional Korean medicine. Methods: By October 2019, the relevant studies on the periodic therapy of endometriosis were searched using the Chinese National Knowledge Infrastructure Database (CNKI) and Oriental Medicine Advanced Searching Integrated System (OASIS). Results: Finally, three Randomized controlled trials, one case study, two clinical observational studies were selected. In all studies, herbal medicine periodic therapy has been effective in improving symptoms of endometriosis. Blood-activating and stasis-dispelling medicinal were the most commonly used before menstruation and during menstruation, and tonifying and replenishing medicinal were the most commonly used after menstruation. According to the one study, which reported safety, herbal medicine was safe. Conclusions: Although limited due to a lack of literature, periodic therapy is effective in improving endometriosis related symptoms and preventing recurrence. A well-designed study and experimental studies for the identification of the mechanism are needed.

The Effect of Integrated Medicine for Polycystic Ovary Syndrome Subfertility Patients; A Systematic Review and Meta-Analysis (다낭성 난소 증후군을 이환하는 난임 환자에서 통합 의학 치료의 효과 : 체계적 문헌 고찰 및 메타분석)

  • Bae, Ju-Eun;Park, Kyung-Dug;Yoon, Young-Jin
    • The Journal of Korean Obstetrics and Gynecology
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    • v.30 no.4
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    • pp.59-76
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    • 2017
  • Objectives: The purpose of this study is to investigate the effect on both herbal medicine periodic therapy and western medicine for polycystic ovary syndrome subfertility. Methods: We searched 8 electronic databases and search keywords were 'PCOS' and 'periodic therapy' or 'cyclic treatment'. We included randomized controlled clinical trials (RCTs) using the periodic therapy combined western medicine for PCOS patients. Results: We selected 8 studies. In studies, there were three studies in which the menstrual cycle was divided into 2 periods, one study divided into 3 periods, and four study divided into 4 periods. The meta-analysis of the 7 trials indicated that pregnancy rates integrated clomiphene and periodic therapy were higher than clomiphene alone. Conclusions: The periodic therapy combined western medicine for PCOS subfertility patients seems to improve pregnancy rates from this research. However, this result should be taken cautiously by unclear risk of bias. It would be necessary to fulfill further clinical study with herbal medicine periodic therapy on PCOS in Korean medicine to establish standard evidence of them.

The study of stochastic inventory model with setup cost and backorder rate (Setup cost와 Backorder rate를 고려한 확률적 재고모형에 관한 연구)

  • 유승우;서창현;김경섭
    • Proceedings of the Korea Society for Simulation Conference
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    • 2003.06a
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    • pp.129-134
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    • 2003
  • In this paper, we determine optimal reduction in the lead time and setup cost for some stochastic inventory models. And we propose more general model that allow the backorder rate as a control variable. We first assume that the lead time demand follows a normal distribution. And we assume that the backorder rate is dependent on the length of lead time through the amount of shortages. The stochastic models analyzed in this paper are the classical continuous and periodic review policy models with a mixture of backorders and lost sales. For each of these models, we provide a sufficient conditions for the uniqueness of the optimal operating policy. We also develop algorithms for solving these models and provide illustrative numerical examples.

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Toward the computational rheometry of filled polymeric fluids

  • Hwang, Wook-Ryol;Hulsen Martien A.
    • Korea-Australia Rheology Journal
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    • v.18 no.4
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    • pp.171-181
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    • 2006
  • We present a short review for authors' previous work on direct numerical simulations for inertialess hard particle suspensions formulated either with a Newtonian fluid or with viscoelastic polymeric fluids to understand the microstructural evolution and the bulk material behavior. We employ two well-defined bi-periodic domain concepts such that a single cell problem with a small number of particles may represent a large number of repeated structures: one is the sliding bi-periodic frame for simple shear flow and the other is the extensional bi-periodic frame for planar elongational flow. For implicit treatment of hydrodynamic interaction between particle and fluid, we use the finite-element/fictitious-domain method similar to the distributed Lagrangian multiplier (DLM) method together with the rigid ring description. The bi-periodic boundary conditions can be effectively incorportated as constraint equations and implemented by Lagrangian multipliers. The bulk stress can be evaluated by simple boundary integrals of stresslets on the particle boundary in such formulations. Some 2-D example results are presented to show effects of the solid fraction and the particle configuration on the shear and elongational viscosity along with the micro-structural evolution for both particles and fluid. Effects of the fluid elasticity has been also presented.