• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.19-20
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• 2007

• 대한수학회보
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• 제38권4호
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• pp.763-772
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• 2001

The rate of convergence for an almost surely convergent series $S_n={\Sigma^n}_{i-1}X_i$ of independent random variables is studied in this paper. More specifically, when S$_{n}$ converges almost surely to a random variable S, the tail series $T_n{\equiv}$ S - S_{n-1} = {\Sigma^\infty}_{i-n} X_i$ is a well-defined sequence of random variables with T$_{n}$ $\rightarrow$ 0 almost surely. Conditions are provided so that for a given positive sequence {$b_n, n {\geq$ 1}, the limit law sup$_{\kappa}\geqn | T_{\kappa}|/b_n \rightarrow$ 0 holds. This result generalizes a result of Nam and Rosalsky [4].

• 한국전자파학회논문지
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• 제22권2호
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• pp.236-244
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• 2011

본 논문에서는, Glass 안테나의 특성과 휴대성 및 제작상의 장점이 있는 다이폴 형태의 Flexible T-DMB 안테나를 제안하였다. 차량의 전면 유리 최외각에 위치하는 안테나를 구현하기 위하여 차체의 영향에 따른 안테나의 특성과 안테나의 부착 위치에 따라 달라지는 안테나 특성을 고려하여 급전 선로 사이에 매칭 회로를 추가하여 안테나의 입력 정합 특성을 높였다. 차량의 전면 유리에서의 실험 결과, T-DMB(174~216 MHz) 대역에서 안테나의 입력 반사 손실은 -6 dB 이하를 기준으로 모두 만족하였으며, 위치 변화에도 T-DMB 대역을 만족하였다.

• Geomechanics and Engineering
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• 제4권2호
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• pp.135-150
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• 2012

This paper presents the study of the effect of microorganism Bacillus pasteurii on the properties such as Atterbergs' limit and unconfined compressive strength of cohesive soils. The results of this study reveal that the liquid limit and plasticity index for all clay soils decreased and the unconfined compressive strength increased. Decrease in plasticity index is very high for Kuttanad clay followed by bentonite and laterite. The unconfined compressive strength increased for all the soils. The increase was high for Kuttanad soil and low for laterite soil. After 24 h of treatment the improvement in the soil properties is comparatively less. Besides the specific bacteria selected Bacillus pasteurii, other microorganisms may also be taking part in calcite precipitation thereby causing soil cementation. But the naturally present microorganisms alone cannot work on the calcite precipitation.

• 한국재료학회지
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• 제5권5호
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• pp.598-605
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• 1995

Thin films of $YB_{2}Cu_{3}O_{7-d}$ were prepared on various substrated of MgO(100), $SrTiO_{3}$, and $LaAlO_{3}$ by using off-axis magentron sputtering methods and annealing in-situ. The prarameters of film fabrication processes had been optimized through a "follow the lcoal maxima" strategy to yield good quality films in therms of the critical temperature $T_{c}$ and the critical current density $J_{c}$. Optimizedproecsses employing a plane magndtron and an cylindrical magnetron yielded $T_{c}$>90K along with $J_{c}$$10^{6}$A/$\textrm{cm}^2$ at 77K and > 2${\times}$$10^{7}$A/$\textrm{cm}^2$ at 5K. The sampels, however, showed degradationinthe properties, after chemical etching for fabrication of microbridges with the line width of 2-10 mocrons. In particular, the value of $T_{c}$ for the microbridges of 2microns was as small as 80%. The degradation was strongly dependent on the line width through a formula : $T_{c}$(e)=$T_{c}$)b) [1-a exp(-1000 bL)} where $T_{c}$(e) and $T_{c}$ (b) are the values of $T_{c}$ in the absolute scale measured after and before chemical etching, respectively and L is the line width in mm. By utilizing a best fitting technique, the proper constant values of a and to b were found as exp(-1.2) and 0.22, respectively. This formula was very useful in estimatiing the upper limit of the device operationtemperature.

• 대한임상검사과학회지
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• 제36권2호
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• pp.121-126
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• 2004

The primary goal of six sigma is to improve patient satisfaction, and thereby profitability, by reducing and eliminating defects. Defects may be related to any aspect of customer satisfaction: high product quality, schedule adherence, cost minimization, process capability indices, defects per unit, and yield. Many six sigma metrics can be mathematically related to the others. Literally, six means six standard deviations from the mean or median value. As applied to quality metrics, the term indicates that failures are at least six standard deviations from the mean or norm. This would mean about 3.4 failures per million opportunities for failure. The objective of six sigma quality is to reduce process output variation so that on a long term basis, which is the customer's aggregate experience with our process over time, this will result in no more than 3.4 defect Parts Per Million(PPM) opportunities (or 3.4 Defects Per Million Opportunities. For a process with only one specification limit (upper or lower), this results in six process standard deviations between the mean of the process and the customer's specification limit (hence, 6 Sigma). The results of applicative six sigma experiment studied on 18 items TP, ALB, T.B, ALP, AST, ALT, CL, CK, LD, K, Na, CRE, BUN, T.C, GLU, AML, CA tests in clinical chemistry were follows. Assessment of process performance fits within six sigma tolerance limits were TP, ALB, T.B, ALP, AST, ALT, CL, CK, LD, K, Na, CRE, BUN, T.C, GLU, AML, CA with 72.2%, items that fit within five sigma limits were total bilirubin, chloride and sodium were 3 sigma. We were sure that the goal of six sigma would reduce test variation in the process.

• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.22-27
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• 2023

Magnetic properties of MgB₂ superconducting powder were investigated. M(H), the magnetic field H dependence of magnetization M, was measured and analyzed using a PPMS instrument. The MgB₂ superconducting powder showed high critical current density J_c > ~ 10⁷ A/cm² and clean limit superconducting properties. The equilibrium magnetization M_eq properties of MgB₂ powders exhibiting various superconducting properties were studied. We find that the equilibrium magnetization M_eq(H) properties of MgB₂ powders showing conventional BCS properties deviate from the predictions of the standard local-London theory at temperatures below T = 19 K and are in good agreement with the generalized nonlocal-London theory. Nonlocal-London analysis was used to determine and analyze the nonlocal parameters. The temperature dependence of the London penetration depth values λ(T) was studied.

• 한국강구조학회 논문집
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• 제21권5호
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• pp.451-459
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• 2009

본 논문은 냉간성형 각형강관 T형 접합부의 면내 휨모멘트를 평가하는데 목적이 있다. 이전 연구로부터, 주관 폭에 대한 지관 폭의 비가 0.71이하인 T형 접합부는 뚜렷한 최대 휨강도를 나타내지 못하는 접합부의 파괴모드는 주관 플랜지의 휨파괴이다. Zhao에 의해 수행된 실험을 포함한 결과로부터 주관 폭두께비는 ${16.7{\leq}2{\gamma}(=B/T){\leq}33}$이고, 주관 폭에 대한 지관 폭의 비인 폭비는 ${0.34{\leq}{\beta}(=b_{1}/B){\leq}0.71}$의 범위인 냉간성형 각형강관 T형 접합부에 대한 최대 휨강도 정의를 위한 변형제한치는 주관폭(B)의 1% 변형이며, 최대 휨강도는 1.5M1%B로 정의할 수 있다. 기본형에 대한 항복선 모델과 기존 연구자들에 의해 수정 제안된 항복선 모델식을 검토하여 실험결과와 비교한 결과, Zhao의 제안식이 가장 좋은 대응도와 분포도를 보였다. 따라서, 각형강관 T형 접합부에 대한 면내 설계 휨강도식으로 Zhao가 수정 제안한 항복선 모델식을 적용하는 것이 가장 합리적인 것으로 생각된다.

• Structural Engineering and Mechanics
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• 제49권1호
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• pp.65-80
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• 2014

This paper reports on the development of a minimum cost design model and its application for obtaining economic designs for reinforced High Strength Concrete (HSC) T-sections in bending under ultimate limit state conditions. Cost objective functions, behavior constraint including material nonlinearities of steel and HSC, conditions on strain compatibility in steel and concrete and geometric design variable constraints are derived and implemented within the Conjugate Gradient optimization algorithm. Particular attention is paid to problem formulation, solution behavior and economic considerations. A typical example problem is considered to illustrate the applicability of the minimum cost design model and solution methodology. Results are confronted to design solutions derived from conventional design office methods to evaluate the performance of the cost model and its sensitivity to a wide range of unit cost ratios of construction materials and various classes of HSC described in Eurocode2. It is shown, among others that optimal solutions achieved using the present approach can lead to substantial savings in the amount of construction materials to be used. In addition, the proposed approach is practically simple, reliable and computationally effective compared to standard design procedures used in current engineering practice.

• 대한수학회보
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• 제54권4호
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• pp.1195-1219
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• 2017

In this paper, the limit behavior of solution for the $Schr{\ddot{o}}dinger$ equation with random dispersion and time-dependent nonlinear loss/gain: $idu+{\frac{1}{{\varepsilon}}}m({\frac{t}{{\varepsilon}^2}}){\partial}_{xx}udt+{\mid}u{\mid}^{2{\sigma}}udt+i{\varepsilon}a(t){\mid}u{\mid}^{2{\sigma}_0}udt=0$ is studied. Combining stochastic Strichartz-type estimates with $L^2$ norm estimates, we first derive the global existence for $L^2$ and $H^1$ solution of the stochastic $Schr{\ddot{o}}dinger$ equation with white noise dispersion and time-dependent loss/gain: $idu+{\Delta}u{\circ}d{\beta}+{\mid}u{\mid}^{2{\sigma}}udt+ia(t){\mid}u{\mid}^{2{\sigma}_0}udt=0$. Secondly, we prove rigorously the global diffusion-approximation limit of the solution for the former as ${\varepsilon}{\rightarrow}0$ in one-dimensional $L^2$ subcritical and critical cases.