• 한국농공학회지
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• 제19권4호
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• pp.4533-4543
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• 1977

The purpose of this study was to investigate and compare flow discharges of rectangular, V-notch and trapezoidal type of cutthrooat flumes, and the published data for trapezoidal parshall flumes. And the trapezoidal cutthroat flumes were also compared in their accuracy of discharge measurements for various convergence ratios in the inlet section and divergence ratios in the outlet section. Five flumes were studied, and all the flumes were 45cm long with flat-bottom and were made of well-finished transparent acryl plate of 3mm thickness. One rectangular, one V-notch and three trapezoidal types were numbered 1 to 5 as shown in Fig. III-1. The measured depth of water was ranged from 5 to 20cm. The results obtained in this study are summarized as follows: 1. The general discharge equations for tested prototypes are listed for free flow in Table IV-1 and for submergence flow in Table IV-4. 2. In both free and submerged flow, the accuracy of the discharge formula obtained by this test is highly significant at 1% level as shown in Table IV-2 and Table IV-6. The accuracy of disharges measured depends upon the convergence and divergence ratios in the trapezoidal types: the less the ratios of convergence as well as divergence, the lower the accuracy. 3. Submergence ratios tend to increase in the order of flume number except flume No. 4. This implies that trapezoidal cutthroat flumes are more acceptable than rectangular or V-notch ones for free flow. 4. The transition submergence for the trapezoidal Parshall flumes ranges from 80-85 percent, which is slightly higher than the tested flume. However, the trapezoidal cutthroat flume No. 5 has higher transition submergence ratio, ranging from 73-78 percent, than other trapezoidal ones. The difference between the trapezoidal Parshall flumes and the trapezoidal cutthroat flumes in transition submergence seems small enough to be ignored in their field use. 5. Trapezoidal cutthroat flume is simple and economical to construct in existing openchannels whose shapes are generally trapezoidal. In order to obtain the best rating accuracy, flume No. 3 among the tested trapezoidal types is recommended, because it shows the highest accuracy for both free and submerged flow.

• 한국융합학회논문지
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• 제11권2호
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• pp.309-314
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• 2020

본 연구는 전통 식재료로 많이 사용되는 10종의 약용식물 및 채소류 추출물과 10종 혼합추출물의 항산화 효과를 살펴보기 위해서 디자인되었다. 세포 생존률은 MTS assay로, 항산화효과는 DPPH free radical 소거능, Riboflavin 유래 Superoxide 억제활성(SQA)에 의한 항산화활성을 측정하였다. 그 결과 세포생존률은 10종 약용식물 및 채소류 추출물과 10종 혼합추출물 모두 0.5mg/mL에서 대조군과 유사한 생존율을 보였다. DPPH free radical 소거능은 Cinnamomum cassia Blume, Eugenia caryophyllata Thunb. Arctium lappa, Total extract가 우수하였고, Riboflavin 유래 Superoxide 억제활성(SQA)은 Cinnamomum cassia Blume, Arctium lappa, Prunus mume Sieb. et Zucc., 우수하였으나, Total extract가 가장 우수한 항산화 효과를 보였다. 전통식재료로 사용되는 약용식물 및 채소 추출물과 혼합추출물의 항산화 효과를 비교한 결과, 단독으로 사용하는 것보다 혼합물로 사용시 항산화능이 증가되었다. 이는 항산화 기능성 소재로 활용이 가능한 것으로 사료되며, 향후 항산화 소재 개발 시 가치가 있을 것으로 사료된다.

• Kyungpook Mathematical Journal
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• 제50권4호
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• pp.565-574
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• 2010

In this paper we introduce the concept of lacunary statistical and lacunary strongly convergence of generalized difference sequence of fuzzy real numbers. We prove some inclusion relations and also study some of their properties.

• 한국융합학회논문지
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• 제7권6호
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• pp.307-315
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• 2016

본 연구는 인터벌 태권도 프로그램을 통하여 중년비만여성들의 코티졸, 유리지방산 및 근 손상지표에 어떠한 변화가 나타나는지를 알아보고자 하였다. 이를 위해 중년비만 여성을 대상으로 최대심박수를 활용한 80~85%의 운동강도로 매회 40분간 실시되는 인터벌 태권도 운동을 주 3회씩 8주간 실시하였으며, 다음과 같은 결과를 얻었다. 첫째, 코티졸은 8주간 인터벌 태권도 프로그램 전 후 감소를 보였으나 유의한 변화는 나타나지 않았다. 둘째, 유리지방산은 8주간 인터벌 태권도 프로그램 전 후 감소를 보였으며 유의한 변화가 나타났다. 셋째, 근 손상지표는 8주간 인터벌 태권도 프로그램 전 후 감소를 보였으나 유의한 변화는 나타나지 않았다. 본 연구결과를 통해 인터벌 태권도 운동은 스트레스를 이겨내는 내성 및 저항력 향상과 근 손상 예방 효과는 다소 낮았으나, 지방 산화 능력 증가를 위한 운동 프로그램으로 활용될 수 있을 것이라는 결론을 얻었다.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.49-60
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• 2022

Motivated by the high-resolution properties of high-order Weighted Essentially Non-Oscillatory (WENO) and flux limiter (FL) for steep-gradient problems and the robust convergence of Jacobian-free Newton-Krylov (JFNK) methods for nonlinear systems, the preconditioned JFNK fully implicit high-order WENO and FL schemes are proposed to solve the transient two-phase two-fluid models. Specially, the second-order fully-implicit BDF2 is used for the temporal operator and then the third-order WENO schemes and various flux limiters can be adopted to discrete the spatial operator. For the sake of the generalization of the finite-difference-based preconditioning acceleration methods and the excellent convergence to solve the complicated and various operational conditions, the random vector instead of the initial condition is skillfully chosen as the solving variables to obtain better sparsity pattern or more positions of non-zero elements in this paper. Finally, the WENO_JFNK and FL_JFNK codes are developed and then the two-phase steep-gradient problem, phase appearance/disappearance problem, U-tube problem and linear advection problem are tested to analyze the convergence, computational cost and efficiency in detailed. Numerical results show that WENO_JFNK and FL_JFNK can significantly reduce numerical diffusion and obtain better solutions than traditional methods. WENO_JFNK gives more stable and accurate solutions than FL_JFNK for the test problems and the proposed finite-difference-based preconditioning acceleration methods based on the random vector can significantly improve the convergence speed and efficiency.

• Journal of information and communication convergence engineering
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• 제6권1호
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• pp.6-9
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• 2008

In future domestic context aware applications the location of mobile devices is often required. Ultrasonic technology enables high resolution indoor position measurements. A disadvantage of state-of-art ultrasonic systems is that several base stations are required to estimate 3D position. This study aims to evaluate the efficiency and effectiveness of using UPS as a 3D free-hand writing or drawing tool. The processes include the design and testing of UPS as an efficient 3D free-hand writing or drawing tool in the air. The paper will further explain the system architecture of the UPS and how to use GPS as 3D free-hand writing or drawing tool. The efficiency and effectiveness of the system was confirmed by a computer software simulation. The software will further display the result of drawing or writing from the user by graphics. As a result, it is possible to implement UPS as a 3D free-hand writing or drawing tool in the air.

• 한국정보컨버전스학회논문지
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• 제6권2호
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• pp.57-60
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• 2013

본 논문에서는 실제 누진다초점렌즈를 착용하는 중장년층을 대상으로 기존 누진다초점렌즈 착용자와 프리폼 누진다초점렌즈 착용자들로 분리하여 만족도와 개선방향 등을 조사하고 향후 누진다초점렌즈의 발전방향을 예측해 보았다. 조사 결과 누진다초점렌즈에 대한 착용만족도는 일반 누진다초점렌즈에 비해 프리폼 누진다초점렌즈가 월등하게 높게 나타났다. 프리폼 누진다초점렌즈는 기존 누진다초점렌즈에 비해 가격이 더 비싸지만 기존 누진다초점렌즈보다 더욱 더 넓은 시야를 제공하고 장용자의 여러 가지 변수에 맞게 개인맞춤 할 수 있다는 점 등에서 충분한 이점들로 가지고 있다는 것을 확인할 수 있었다. 머지않은 미래에 프리폼 누진다초점렌즈는 대부분의 중장년층이 착용하는 가장 대중적인 누진다초점렌즈로 자리 잡을 것으로 예상된다.

• Smart Structures and Systems
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• 제16권5호
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• pp.891-918
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• 2015

In many of microdevices a part of a microbeam is covered by a piezoelectric layer. Depend on the application a DC or AC voltage is applied between upper and lower side of the piezoelectric layer. A common method in many of previous works for evaluating the response of these structures is discretizing by Galerkin method. In these works often single mode shape of a uniform microbeam i.e. the microbeam without piezoelectric layer has been used as comparison function, and so the convergence of the solution has not been verified. In this paper the Galerkin method is used for discretization, and a comprehensive analysis on the convergence of solution of equation that is discretized using this comparison function is studied for both clamped-clamped and clamped-free microbeams. The static and dynamic solution resulted from Galerkin method is compared to the modal expansion solution. In addition the static solution is compared to an exact solution. It is denoted that the required numbers of uniform microbeam mode shapes for convergence of static solution due to DC voltage depends on the position and thickness of deposited piezoelectric layer. It is shown that when the clamped-clamped microbeam is coated symmetrically by piezoelectric layer, then the convergence for static solution may be obtained using only first mode. This result is valid for clamped-free case when it is covered by piezoelectric layer from left clamped side to the right. It is shown that when voltage is AC then the number of required uniform microbeam shape mode for convergence is much more than the number of required mode in modal expansion due to the dynamic effect of piezoelectric layer. This difference increases by increasing the piezoelectric thickness, the closeness of the excitation frequency to natural frequency and decreasing the damping coefficient. This condition is often indefeasible in microresonator system. It is concluded that discreitizing the equation of motion using one mode shape of uniform microbeam as comparison function in many of previous works causes considerable errors.

• 한국세라믹학회지
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• 제51권6호
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• pp.527-532
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• 2014

$0.97Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3-0.03LaFeO_3$ lead-free piezoelectric ceramics were fabricated by a solid state reaction method. $LaFeO_3$ additives were added to $Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3$ for volatile compensation of bismuth and sodium ions in the sintering process. To create A-site vacancies, the mole ratio and charge valence of A-site ions ($Bi^{3+}$, $Na^+$ and $K^+$) were controlled. The improved piezoelectric properties were observed by addition of $LaFeO_3$ and control of A-site vacancies. In particular, a $d_{33}^*(S_{max}/E_{max})$ value of 614pm/V and an electric field induced strain of 0.33% was observed in $0.97Bi_{0.505}(Na_{0.78}K_{0.22})_{0.485}TiO_3-0.03LaFeO_3$ ceramic.

• Journal of information and communication convergence engineering
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• 제9권1호
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• pp.105-109
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• 2011

In this paper, we study the dominating-free sest which is defined as follows: k points called servers and n points called clients in the plane are given. For a point p in the plane is said to be dominated by a client c if for every server s, the distance between s and p is greater than the distance between s and c. The dominating-free set is the set of points in the plane which aren't dominated by any client. We present an O(nklogk+$n^2k$) time algorithm for computing the dominating-free set under the $L_1$-metric. Specially, we present an O(nlogn) time algorithm for the problem when k=2. The algorithm uses some variables and 1-dimensional arrays as its principle data structures, so it is easy to implement and runs fast.