• Structural Engineering and Mechanics
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• 제77권1호
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• pp.1-17
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• 2021

The influence of prestress force on the fundamental frequency and static deflection shape of uncracked Prestressed Concrete (PC) beams with a parabolic bonded tendon was examined in this paper. Due to the conflicts among existing theories, the analytical solutions for properly considering the dynamic and static behavior of these members is not straightforward. A series of experiments were conducted for a total period of approximately 2.5 months on a PC beam made with high strength concrete, subsequently and closely to the 28 days of age of concrete. Specifically, the simply supported PC member was short term subjected to free transverse vibration and three-point bending tests during its early-age. Subsequently, the experimental data were compared with a model that describes the dynamic behavior of PC girders as a combination of two substructures interconnected, i.e., a compressed Euler-Bernoulli beam and a tensioned parabolic cable. It was established that the fundamental frequency of uncracked PC beams with a parabolic bonded tendon is sensitive to the variation of the initial elastic modulus of concrete in the early-age curing. Furthermore, the small variation in experimental frequency with time makes doubtful its use in inverse problem identifications. Conversely, the relationship between prestress force and static deflection shape is well described by the magnification factor formula of the "compression-softening" theory by assuming the variation of the chord elastic modulus of concrete with time.

• The Journal of Asian Finance, Economics and Business
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• 제9권9호
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• pp.317-325
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• 2022

The simple regression model (SRM) is used in this study to look at potential economic growth-influencing factors. The sample's period runs from 2005 to 2019. The data was gathered from various ministries and government agencies such as the Central Bank of Afghanistan's Statistical Bulletin, the World Bank, the United Nations (UN), World Bank open data, NASA, Ministry of Finance (MoF), Ministry of Economy (MoE), and Central Bank of Afghanistan's Statistical Bulletin (CBA), as well as the internet and news. There is an urgent need to ensure that taxes are collected in the most efficient manner possible because one of the enormous management gaps in Afghanistan over the last two decades has been tax evasion. According to the results of this study, tax evasion has a negative and significant impact on Afghanistan's economic growth. We can affirm that the subject of this article is among the most significant topics recently discussed in my country. If the right solutions are implemented, It can significantly contribute to quickening the cycle of the developing Afghan economy and turning it from an unstable to a sustainable one.

• Journal of Dental Anesthesia and Pain Medicine
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• 제20권2호
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• pp.73-81
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• 2020

Background: The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO₂) and peripheral oxygen saturation (SpO₂) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies. Materials and Methods: Each volunteer was placed in a semi-Fowler's position and connected to a breathing circuit to administer the hypoxic gas mixture containing medical air, oxygen, nitrogen, and carbon dioxide. Volunteers were exposed to various levels of induced hypoxia over 70-100% arterial oxygen saturation (SaO₂). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO₂ and SpO₂ were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA). Results: In total, 2899 SpO₂ data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k_out = 0.942 1/min, Imax = 0.802, IC₅₀ = 85.3%, γ = 27.3. Conclusion: The changes in SpO₂ due to decreases in FiO₂ well explained by the turnover model with inhibitory function as a sigmoidal model.

• 한국항만학회지
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• 제13권2호
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• pp.399-408
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• 1999

Copeland’s(1985) hyperbolic mild-slope equation including diffraction refraction and reflection in the wave field is used as a governing equation in this study. The result of Maruyama & Kajima(1985) is used to calculate wave direction and that of Watanabe & Maruyama(1986) is used as a energy dissipation formula. Numerical solutions are obtained by the Leap-Frog scheme and compared with Watanabe & Maruyama’s (1984) hydraulic experimental results and numerical simulation results for the detached breakwater. This wave model is applied to a detached breakwater and compared with Watanabe and Maruyama’s (1984) hydraulic model results to check the characteristics of reflected wave field around a detached breakwater. The distribution of wave height and we phase in front of a detached breakwater is more accurate than the Watanabe and Maruyama’s numerical results. The results from our wave model show good agreements with the others and also show nonlinear effects around the detached breakwater. This model is applied to the Gamcheon harbor of pusan. the field observations were carried out at Pusan harbor wave station in 1986-1995 and the results were accepted as a design wave condition in this study. The wave height and wave period was measured by Dong-A university at one station in the Gamcheon harbor in 1996-1997 and used as a calibration criterion. The measured data were used as input data for the numerical simulation and also compared with simulated results. The numerical simulation shows a fairly good results which considering the effect of topographic characteristics and effect of narrow entrance due to two separated breakwaters in Gamcheon harbor. The wave distribution characteristics inside Gamcheon harbor is quite different with the offshore wave direction and wave period.

• Preventive Nutrition and Food Science
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• 제14권2호
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• pp.142-147
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• 2009

In this study, the selenium (Se) accumulations of soybean sprouts and mungbean sprouts treated with various concentrations of Se-solutions were evaluated, as part of a broader effort to produce Se-enriched variants of the plants. Four levels of sodium selenate ($Na_{2}SeO_{4}$)-dissolved solutions (i.e. 0, T0; 6, T1; 60, T2; and $600{\mu}g/mL$, T3) were prepared and sprayed onto the plants during cultivation. The effect of different spraying periods on Se accumulation was also assessed by watering plant groups once a day for periods of one, two, or three days. Se solution remaining on the surfaces of the plants was washed out by spraying with distilled water on the final day of cultivation. However, the increase of Se accumulation in the plants was found to depend on both Se-concentration and watering period, and the soybean sprouts were determined to accumulate Se more effectively than the mungbean sprouts. Additionally, with regard to Se accumulation in the plants, the period of application of Se solution was determined to be more important than the concentration of the Se solution applied. The averaged total levels of Se-enrichment in whole soybean sprouts at T0, T1, T2, and T3 were 0.26, 65.86, 179.62, and $525.12{\mu}g/dry$ matter (DM) g, respectively, and the relative equations relating Se enrichment in soybean sprouts (Y) against watering days (X) were Y=32.505X-36.17 (T1), Y=88.46X-92.04 (T2), and Y=251.11X-254.9(T3). The averaged total levels of Se-enrichment in the whole mungbean sprouts at T1, T2, and T3 group were 0.05, 3.64, and $101.43{\mu}g/DM$ g, respectively, and the relative equations relating Se enrichment (Y) to watering days (X) for mungbean sprouts were Y=1.67X-1.3467 at T1 and Y=48.035X-46.907 at T2. The results of this study suggest that soybean sprouts and mungbean sprouts enriched with bioavailable Se can be produced on a large scale by Se supplementation, allowing for the development of healthy functional foods such as Se-enriched mungbean sprout soups and salads, Se-enriched functional drink and food additives, and selenium tablets to promote health.

• Journal of Oral Medicine and Pain
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• 제37권1호
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• pp.27-33
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• 2012

피부와 구강점막에서 발견되는 편평태선은 만성 염증성 질환으로 세포매개성 면역반응이 주로 언급되고 있으나 아직 정확한 원인은 밝혀지지 않았다. 따라서 완전한 치료법은 아직 없으며 증상의 완화를 치료목표로 하고 있다. 본 연구에서는 구강편평태선의 일차적인 치료법으로 사용되는 corticosteroid의 두 가지 가글용액의 효과를 비교하였다. 2002년부터 2010년까지 부산대학교 치과병원 구강내과에서 구강편평태선으로 진단받은 환자들 중 corticosteroid 가글용액을 처방받은 환자들 총 180명의 환자기록을 조사하였다. 사용된 두 종류의 가글용액은 각각 dexamethasone(dexamethasone disodium phosphate, 0.05%)과 prednisolone($solondo^{(R)}$)을 포함하는 용액이었으며 약물 사용 후 증상의 완화 및 재발의 시기를 기록하여 분석하였다. Dexamethasone gargle(dexa gargle) 처방군은 33명(여성 25명, 남성 8명), prednisolone gargle(solon gargle)처방군은 147명(여성 114명, 남성 33명)이었으며 환자군의 평균연령대는 50대였다. 약물투여 후 초기 2주이내에 증상이 호전된 경우는 dexa gargle을 사용한 환자군에서 유의성 있게 나타났으나 증상재발의 경우는 두가지 가글용액의 차이가 나타나지 않았다. 구강편평태선 환자에 대한 도포용 스테로이드 가글을 이용한 치료에서 증상의 빠른 호전을 기대하기 위해서는 solon gargle보다는 dexa gargle을 사용할 수 있으나 재발율에 있어서는 두 약물의 차이가 발견되지 않았다.

• 원예과학기술지
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• 제31권4호
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• pp.423-428
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• 2013

Although closed soilless culture is useful for saving water and fertilizers with minimizing environmental pollution, adequate management of nutrient solutions is still not stabilized in greenhouse cultivation. In order to investigate the problems occurred in closed soilless culture of Paprika (Capsicum annuum L., cv. Fiesta), we compared ion balance, fruit yield, and the water and fertilizer use efficiencies in the closed system with those in the open system. The plants were grown in rockwool culture with a nutrient solution of EC $2.5dS{\cdot}m^{-1}$. After 4 weeks of treatment, individual ratio of $NO{_3}^-$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ to total ion concentrations ($meq{\cdot}L^{-1}$) decreased from the initial value, especially the biggest decrement was observed in $K^+$, and on the other hand, $SO{_4}^{2-}$, $Cl^-$, and $Na^+$ were accumulated in the closed system. Yields after four-time harvests were 19% higher in the open system than in the closed system. Total volume of water used per unit area ($m^2$) in the open system was 20% higher, but the total water use per fruit was not significantly different between the two systems, while t total fertilizer use per fruit was 78% higher in the closed system. Amount of marketable fruits was not significantly different between the two systems. We concluded that the increase in $K^+$ supply and the replenishment of recycled nutrient solution every four weeks were required for preventing the imbalance or depletion of nutrients in the close soilless culture of paprika plants to get more balanced nutrient composition during whole cultivation period.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1997년도 춘계 학술대회 발표집
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• pp.93-99
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• 1997

Most of the past studies on FMS scheduling problems may be classified into two classes, namely off-line scheduling and on-line scheduling approach. The off-line scheduling methods are used mostly for FMS planning purposes and may not be useful real time control of FMSs, because it generates solutions only after a relatively long period of time. The on-line scheduling methods are used extensively for dynamic real-time control of FMSs although the performance of on-line scheduling algorithms tends vary dramatically depending on various configurations of FMS. Current study is about finding a better on-line scheduling rules for FMS operations. In this study, we propose a method to create priority functions that can be used in setting relative priorities among jobs or machines in on-line scheduling. The priority functions reflect the configuration of FMS and the user-defined objective functions. The priority functions are generated from diverse dispatching rules which may be considered a special priority functions by themselves, and used to determine the order of processing and transporting parts. Overall system of our work consists of two modules, the Priority Function Evolution Module (PFEM) and the FMS Simulation Module (FMSSM). The PFEM generates new priority functions using input variables from a terminal set and primitive functions from a function set by genetic programming. And the FMSSM evaluates each priority function by a simulation methodology. Based on these evaluated values, the PFEM creates new priority functions by using crossover, mutation operation and probabilistic selection. These processes are iteratively applied until the termination criteria are satisfied. We considered various configurations and objective functions of FMSs in our study, and we seek a workable solution rather than an optimum or near optimum solution in scheduling FMS operations in real time. To verify the viability of our approach, experimental results of our model on real FMS are included.

• 한국해안·해양공학회논문집
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• 제26권5호
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• pp.300-313
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• 2014

파-지반의 상호작용 해석에 지금까지는 대부분 무한두께를 갖는 해저지반 상의 진행파와 무한두께 혹은 유한두께의 해저지반 상에서 완전중복파에 대해서만 해석해가 제안되어 있다. 본 연구에서는 임의반사율의 부분중복파동장에 선형파 이론과 유한두께를 갖는 해저지반에 Biot(1941) 3차원 압밀이론 및 지반탄성론에 기초한 유효응력 개념을 각각 적용하여 지반 내 동적응답에 관한 해석해를 새롭게 유도하며, 이에 수심과 반사율만을 변화시킴으로서 기존의 해석해가 간단히 얻어지기 때문에 그의 적용성이 보다 넓다. 본 해석해의 타당성은 무한지반 상의 진행파동장 및 완전중복파동장에 대한 Yamamoto et al.(1978) 및 Tsai & Lee(1994)의 해석해와 비교 검토로부터 검증된다. 또한, 본문에서는 유한깊이를 갖는 해저지반 상의 진행파동장, 완전중복파동장 및 임의반사율의 부분중복파동장에 대해 수심과 주기의 변화에 따른 본 해석해의 변화특성을 면밀히 검토한다. 이로부터 유한깊이의 지반은 무한두께의 경우와는 매우 상이한 지반응답(간극수압, 전단응력, 수평 및 연직 유효응력)을 나타내고, 반사율의 함수인 부분중복파동장에서 지반응답은 완전중복파동장에서의 값보다 일반적으로 작은 값을 나타낸다는 것을 확인할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권4호
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• pp.86-93
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• 2007

최근에 형광물질을 이용한 추적자 시험이 빈번해지고 있다. 본 연구에서는 형광물질 추적자 시험시 농도측정 방법으로서 입상 활성탄을 이용하는 방법의 적용가능성을 실내 및 현장실험을 통해 평가하였다. 실내실험 결과 로다민 WT 및 우라닌 개별용액의 경우 활성탄 흡착 농도는 실제 표준농도와는 일부 차이가 있지만 각 표준농도와 선형성은 매우 뛰어난 것으로 나타났다. 또한 $10{\mu}g/L$ 이상의 형광물질 농도에서는 활성탄의 적용성이 뛰어났다. 한편 두 형광물질을 혼합한 경우에는 간섭의 영향으로 활성탄 적용성이 떨어졌다. 실제 현장에서 활성탄을 이용하여 추적자 시험을 한 결과, 통상적으로 수행하는 직접적인 물시료 채취분석법과 비교하였을 때 활성탄을 이용한 흡착방법도 충분히 현장 적용성이 있으며 저농도에서는 습식 그리고 고농도에서는 건식으로 분석한다면 보다 정확한 형광물질 농도측정이 되는 것으로 나타났다. 특히 오염물질 확산 평가 등이 목적이 아니라 추적자 물질의 도달확인(즉 수리적 연결성 진단)이 주요 목적이고 추적자시험의 예상 소요기간이 길다면 활성탄을 활용한 방법은 매우 비용경제적일 것으로 사료된다.