• 농업과학연구
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• 제37권2호
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• pp.285-293
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• 2010

To secure instream flow at the Yudeung urban stream reach of Daejeon city in South Korea, Yudeung upstream diversion was designed with total water storage of $59{\times}10^4m^3$, and the upstream Seongol reservoir was planned to raise the bank with various sizes. Downstream streamflows were simulated by considering outflows from upstream diversion and reservoir, and after then flow durations were analyzed and compared with flows of no reservoir condition. In case of no diversion or reservoir upstream, flow durations were $1^{st}$ flow of $84.72m^3/s$, $95^{th}$ flow of $2.10m^3/s$, $185^{th}$ flow of $0.92m^3/s$, $275^{th}$ flow of $0.42m^3/s$, and $355^{th}$ flow of $0.31m^3/s$. In case of upstream diversion, flow durations were $1^{st}$ flow of $94.38m^3/s$, $95^{th}$ flow of $2.96m^3/s$, $185^{th}$ flow of $1.22m^3/s$, $275^{th}$ flow of $0.50m^3/s$, and $355^{th}$ flow of $0.35m^3/s$. The increase flow rates were $0.04m^3/s$ in $355^{th}$ flow, $0.08m^3/s$ in $275^{th}$, and $0.30m^3/s$ in 185th. In case of Seongol reservoir with effective storage capacities of $365{\times}10^4m^3$, $544{\times}10^4m^3$, $750{\times}10^4m^3$, and $992{\times}10^4m^3$, flow durations were $85.5{\sim}83.9m^3/s$ on $1^{st}$ flow, $2.85{\sim}2.57m^3/s$ on $95^{th}$ flow, $1.16{\sim}1.27m^3/s$ on $185^{th}$ flow, $0.64{\sim}0.99m^3/s$ on $275^{th}$ flow, and $0.56{\sim}0.94m^3/s$ on $355^{th}$ flow. The increase flow rates were $0.25{\sim}0.63m^3/s$ in $355^{th}$ flow, $0.22{\sim}0.57m^3/s$ in $275^{th}$, and $0.24{\sim}0.35m^3/s$ in $185^{th}$. The more the sizes of upstream reservoirs increased, the $1^{st}$ and $95^{th}$ flows decreased in which coefficients of determination were 0.92, 0.99, respectively and the $185^{th}$, $275^{th}$, and $355^{th}$ flows increased in which coefficients of determination were 0.93 to 0.99.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.395-398
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• 2011

This paper introduces stochastic cash-flow modeling integrated with simulation based scheduling. The system makes use of CPM schedule data exported from commercial scheduling software, computes the best fit probability distribution functions (PDFs) of historical activity durations, assigns the PDFs identified to respective activities, simulates the schedule network, computes the deterministic and stochastic project cash-flows, plots the corresponding cash flow diagrams, and estimates the best fit PDFs of overdraft and net profit of a project. It analyzes the effect of different distributions of activity durations on the distribution of overdrafts and net profits, and improves reliability compared to deterministic cash flow analysis.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.85-92
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• 2016

The paper presents a method to assess system voltage sag performance considering sag durations as well as magnitudes. In general, voltage sag assessment for large power systems is performed only considering sag magnitudes at sensitive load points. However some equipment can be affected by certain sag durations. The duration of the voltage sag is depend on the time of fault current flow in the system. Therefore, the duration can be determined by analyzing the operating characteristic of the protection system. In this paper, an effective method to evaluate sag durations regarding the characteristics and failure rates of the protection system is described. The proposed method can be used to assess the long-term performance of the voltage sags in large power system.

• 대한화학회지
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• 제4권1호
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• pp.1-6
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• 1957

The mobilities and the electrophoretic phenomena of human serum albumin, and of horse serum albumin, etc., on paper were reported, but there is no information about the mobility and the electrophoretic phenomena of ovalbumin. In this study they are determined and considered at various time durations. The mean value of this mobility is compared with the value determined by the electrophoresis in solution. Also, the mobilities of the electroendosmotic flow, which affect on the mobility seriously, are determined at various time durations. Apparatus and method used, are a closed system type and a method with electrode vessels. It is concluded that: 1) The mobilities of ovalbumin have the nearly constant mobilities at six and eight hours of time durations, but it decreases at ten hours of long time duration. Their mean value is (0.243 ${\pm}$ 0.003)cm./hr./v./cm. toward anode at pH 8.0. 2) Under these experimental conditions, ovalbumin cannot be separated into three fractions (A1, A2, A3) on paper. 3) Most of the factors, which affect on the mobility, are fixed by the initial experimental conditions, but the electroendosmotic flow due to the characteristic capillarity of paper is measured. Then, the mean value of its mobilities shows the good constancy, and the value is (0.073 ${\pm}$ 0.0003)cm/hr./v./cm. toward cathode at pH 8.0. 4) By the above facts, if the same paper and the same experimental conditions are chosen, it may be preferred to determine the mobility of the electroendosmotic flow once time, even when many observations are required.

• 설비공학논문집
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• 제12권4호
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• pp.381-387
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• 2000

An experimental study on the stratified fluids was carried out to investigate the flow characteristics, heat transfer through the interface of fluids, and the applications of thermal behaviors in the square cavity. The same volume of water and silicon oil was filled in it. The experiments were performed with the variations of initial temperatures and cooling surface temperatures. And the effect of vertical or horizontal cooling surface positions in the square cavity was investigated. When the cooling surface temperatures were $-4^{\circ}C$ , the supercooling phenomena were observed for both cases of cooling surface positions in the full region regardless of the initial temperature of fluid. In the square cavity with horizontal cooling surfaces, the lower the initial temperatures were, the longer the supercooling durations were, and with vertical cooling surface the lower the initial temperatures were, the shorter the supercooling durations were.

• Journal of Mechanical Science and Technology
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• 제14권8호
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• pp.861-866
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• 2000

Flow induced shape change is important for spatial interpretation of vascular response and for understanding of mechanotransduction in a single cell. We investigated the possible shapes of endothelial cell (EC) in a mathematical model and compared these with experimental results. The linearized analytic solution from the sinusoidal wavy wall and Stokes flow was applied with the constraint of EC volume. The three dimensional structure of the human umbilical vein endothelial cell was visualized in static culture or after various durations of shear stress (20 $dyne/cm^2$ for 5, 10, 20, 40, 60, 120min). The shape ratio (width: length: height) of model agreed with that of the experimental result, which represented the drag force minimizing shape of stream-lining. EC would be streamlined in order to accommodate to the shear flow environmented by active reconstruction of cytoskeletons and membranes through a drag force the sensing mechanism.

• Journal of Oral Medicine and Pain
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• 제47권3호
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• pp.126-134
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• 2022

Purpose: This study aimed to propose an efficient treatment approach for infection with different candida species. Methods: Fifty-three patients who presented with a chief complaint of oral mucosal pain and exhibited positive candida culture findings were divided into two groups (Candida albicans and non-albicans). Pain, mucosal manifestations, salivary flow rates, durations of disease and treatment, and responses to treatment (nystatin and clonazepam) were investigated in both groups. Results: Patients in the C. albicans group exhibited more prominent clinical characteristics (erythematous lesions, tongue coatings, and hyperalgesia) than those in the non-albicans group. In total, 70% of patients in the non-albicans group showed no abnormalities in the oral mucosa. Patients in the C. albicans group showed increased resistance to nystatin treatment compared to those in the non-albicans group, especially with longer disease durations. The patients resistant to nystatin treatment showed positive responses to clonazepam. Conclusions: Patients with oral mucosal pain should be tested for the presence of Candida, even in the absence of mucosal abnormalities, especially those infected with non-albicans species. If no response to antifungal therapy is observed, treatment with clonazepam should be initiated, especially in patients infected with C. albicans.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.243-251
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• 2013

Cash management is a major concern for all contractors in the construction industry. It is arguable that cash is the most critical resource of all. A contractor needs to secure sufficient funds to navigate the project to the end, while keeping an eye on maximizing profits along the way. Past research attempted to address such topic via developing models to tackle the time-cost tradeoff problem, cash flow forecasting, and cash flow management. Yet, little was done to integrate the three aspects of cash management together. This paper, as such, presents a comprehensive model that integrates the time-cost tradeoff problem, cash flow management, and cash flow forecasting. First, the model determines the project optimal completion time by considering the different alternative construction methods available for executing project activities. Second, it investigates different funding alternatives and proposes a project-level cash management plan. Two funding alternatives are considered; they are borrowing and company own financing. The model was built as a combinatorial optimization model that utilizes ant colony search capabilities. The model also utilizes Microsoft Project software and spreadsheets to maintain an environment that incorporates activities, their durations, and other project data, in order to estimate project completion time and cost. Ant Colony Optimization algorithm was coded as a Macro program using VBA. Finally, an example project was used to test the developed model, where it acted reliably in maximizing the contractor's profit in the test project.

• 대한토목학회논문집
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• 제6권3호
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• pp.63-74
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• 1986

댐 지점(地點)에서의 저유량(抵流量)의 지속기간(持續期間)과 재현기간(再現期間)을 고려하여 저수지(貯水池)의 활용(活用) 저수용량(貯水容量)을 확률론적(確率論的)으로 결정하는 방법(方法)을 제안하였다. 확률론적(確率論的) 분석(分析)의 신뢰도를 제고시키기 위해 월유량(月流量) 자료계별(資料系別)의 모의발생(模擬發生)에 흔히 사용되는 모의모형(模擬模型) 중 Monte Carlo 모형(模型)과 Thomas Fiering 모형(模型)의 적합성(適合性)을 비교 검토하였으며 그 결과 월유량(月流量) 자료계열(資料系列)을 표준화(標準化)한 계열월유량자료(系列月流量資料)를 근거로 하는 Monte Carlo 모형(模型)(Monte Carlo-B)이 최적모형(最適模型)으로 선정되었다. Monte Carlo-Bah 모형(模型)에 의해 홍천(洪川)댐 지점(地點)에 대한 200 년간(年間)의 월유량계열(月流量系列)을 발생시켰으며 이로 부터 각종(各種) 지속기간별(持續期間別) 저유하량(抵流下量) 계열(系列)을 작성하였다. 여러 크기의 용수수요(用水需要)를 표시하는 상시유량(常時流量)에 대하여 지속기간별(持續期間別) 저유하량(抵流下量) 계열(系列)의 누가용적해석(累加容積解析)을 실시함으로서 활용저수용량(活用貯水容量)-상시유량(常時流量)-재현기간(再現期間)(Active Storage Draft Recurrence Interval) 관계가 수립되었으며 이 관계(關係)는 조발재현기간별(早魃再現期間別)로 용수수요(用水需要)를 보장할 수 있는 저수지(貯水池)의 활용용량(活用容量)을 결정하는 기준(基準)을 제공하게 된다. 또한, 이 관계(關係)를 사용하여 저수지(貯水池)의 설계재현기간별(設計再現期間別) 만수위(滿水位) 표고별(標高別) 상시가용수량(常時可用水量)을 추정하는 방법(方法)과 특정(特定) 저수지(貯水池)의 용수공급능력(用水供給能力)을 평가(評價)하는 방법(方法)을 예시(例示)하였다.

• 약학회지
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• 제23권1호
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• pp.31-39
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• 1979

Bethanidine was administered into the lateral ventricle of the rabbit brain for the investigation of the effect on the renal function in doses ranging from 0.1 to 1.0mg/kg. In a dose of 0.1 mg/kg, bethanidine did not exhibit significant changes on the renal function of the rabbit, on the other hand, in the doses of 0.3 and 1.0mg/kg bethanidine elicited the reduction of renal plasma flow and glomerular filtration rate with a marked antidiuresis, at the same time bethanidine produced the decrement of urinary sodium and potassium excretion. After intravenous pretreatment of phentolamine, intraventricular bethanidine in a dose of 0.3mg/kg did not produced the antidiuresis and the decrement of urinary sodium and potassium excretion, wherease renal plasma flow and glomerular filtration rate reduced as before of phentolamine pretreatment although the durations of their reduction were shortened. These observations suggest that bethanidine induces the antidiuresis through the centrally mediated mechanism which interposed other factors in addition to sympathetic stimulation affected by phentolamine, alpha adrenergic blocking agent.