• Geomechanics and Engineering
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• 제35권6호
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• pp.617-626
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• 2023

In this study, three-dimensional numerical parametric study was conducted to explore deformation mechanisms of grouped piled-raft-foundation due to lateral load in clays. Effects of load intensity, loading angle, soil stiffness, pile diameter, pile spacing and pile length on foundation deformations were explored. It is found that the smallest and largest movements of pile foundation are induced when the loading angles are 0° and 30°~60°, respectively. By increasing loading angle from 0° to 30°~60°, the resultant horizontal movements and settlements increase by up to 20.0% and 57.1%, respectively. Since connection beams can substantially increase integrity of four piled raft foundation, resultant horizontal movements, settlements and bending moments induced in the piled raft foundation decrease by up to 54.0%, 8.8% and 46.3%, respectively. By increasing soil stiffness five times, resultant horizontal movements and settlements of pile foundation decrease by up to 61.7% and 13.0%, respectively. It is indicated that effects of connection beam and soil stiffness on settlements of pile foundation are relatively small. When pile diameter is less than 1.4 m, deformations of piled raft foundation decrease substantially as a reduction in the pile diameter. Two dimensional groups are proposed to develop calculation charts of horizontal movements and settlements of pile foundation. The proposed calculation charts can directly estimate movements of piled raft foundation under arbitrary loading, ground and pile conditions.

• 한국의학물리학회지:의학물리
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• 제8권1호
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• pp.3-15
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• 1997

Adrenal chromaffin cells secrete catecholamine in response to acetylcholine. The secretory response has absolute requirement for extracellular calcium, indication that $Ca^{2+}$ influx through voltage dependent $Ca^{2+}$ channel (VDCC) is the primary trigger of the secretion cascade. Although the existence of various types of $Ca^{2+}$ channels has been explored using patch clamp technique in adrenal chromaffin cells, the contribution of different types of $Ca^{2+}$ channels to catecholamine secretion remains to be established. To investigate the quantative contribution of different types of $Ca^{2+}$ channels to cate-cholamine secretion, $Ca^{2+}$ current($I_{Ca}$) and the resultant membrane capacitance increment($\Delta{C}_{m}$) were simultaneoulsy measured. Software based phasor detector technique was used to monitor $\Delta{C}_{m}$. After blockade of L type VDCC with nicardipine (1$\mu$M), $I_{ca}$ was blocked to 43.85$\pm$6.72%(mean$\pm$SEM) of control and the resultant ㅿC$_{m}$ was reduced ot 30.10$\pm$16.44% of control. In the presence of nicardipine and $\omega$-conotoxin in GVIA(l$\mu$M), an N type VDCC antagonist, $I_{ca}$ was blocked to 11.62$\pm$2.96% of control and the resultant $\Delta{C}_{m}$ was reduced to 26.13$\pm$8.25% of control. Finally, in the presence of L, N, and P type $Ca^{2\pm}$ channel antagonists(nicardipine, $\omega$-Conotoxin GVIA, and $\omega$-agatoxin IVA, respectively), $I_{ca}$ and resultant $\Delta{C}_{m}$ were almost completely blocked. From the observation of parallel effects of $Ca^{2+}$ channel antagonists on $I_{ca}$ and $\Delta{C}_{m}$, it was concluded that L, N, and also P type $Ca^{2+}$ channels served and $Ca^{2+}$ source for exocytosis and no difference was observed in their efficiency to evoke exocytosis amost L, N, and P type $Ca^{2+}$ channels.

• 한국운동역학회지
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• 제18권4호
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• pp.161-169
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• 2008

이 연구는 성인 남성을 대상으로 계단 너비에 따른 계단 보행의 지지국면 시 하지분절의 역학적 변인을 정량적으로 분석하여, 보다 효과적인 계단의 너비를 제시하고자 실시하였으며, 이를 위해 20대의 남자 대학생 10명이 참여하였다. 계단의 높이는 18cm, 최소폭은 90cm로 동일하나 디딤면의 너비가 각각 26cm, 31cm, 36cm인 세 개의 계단을 사용 하였다. 이때 사용된 계단의 세 번째 디딤면에 지면반력기를 설치하여 지지구간의 하지관절 모멘트를 분석한바 다음과 같은 결론을 얻었다. 상향계단보행에서 발목관절의 굴곡/신전 모멘트변화를 분석한 결과 계단의 너비가 증가 할수록 pull-up 단계의 peak 모멘트가 감소하였으며(p<.05), 무릎관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 무릎에 작용하는 신전모멘트가 중지지기에 증가하는 것으로 나타났다(p<.05). 그러나 고관절에서 차이가 없는 것으로 나타났다. 그리고 하향계단보행에서 발목관절의 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 지지기 동안 저측굴곡과 배측굴곡의 차이가 확연히 나타나는 것으로 나타났으며(p<.05), 무릎관절과 고관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비에 따라 신전 모멘트의 차이가 크지 않은 것으로 나타났다.

• 호남수학학술지
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• 제34권4호
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• pp.533-548
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• 2012

We investigate relations of polynomials $x^n={\Sigma}^{n-1}_{i=0}x^i$ and recurrence sequences. We consider certain variations of the Fibonacci sequence and investigate explicit ways to compute the general nth term.

• Communications for Statistical Applications and Methods
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• 제11권1호
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• pp.1-12
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• 2004

In this paper, Yates' end corrections method is centralized to estimate the mean of a population which has a linear trend in the case of k (the reciprocal of the sampling fraction) even. The efficiency of the resultant method is compared with that of existing methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.407-412
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• 1989

Using the knowledge base which contains the patterns and data of the past experience of a plant, a learning control method is suggested. The knowledge for controlling a plant is stored to the knowledge base and continually modified after performance evaluation of an applied control input. The performance of the resultant knowledge based control system is examined by an application to process.

• 대한수학회논문집
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• 제37권4호
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• pp.989-993
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• 2022

In this paper, we prove Pascal's hexagon theorem by elementary tools only. We follow the well-known route to prove the theorem by Bezóut's theorem, explaining all the details in elementary argument. In particular, we prove a toy version of Study's lemma.

• 한국정보통신학회논문지
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• 제10권7호
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• pp.1188-1195
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• 2006

본 논문은 개량된 분기한정법(branch-and bound method)을 이용하여 고속연산이 가능한 2차원 상태공간 디지털 필터의 설계방법을 제안하였다. 설계된 디지털 필터가 갖는 계수행렬의 모든 요소 값들은 오직 2개의 2의 멱수 (powers-of-two) 의 합으로만 표현되어진다. 따라서 제안된 방법으로 설계한 2 차원 상태공간 디지털필터는 간단한 가산연산만으로 수행이 이루어지므로 고속연산이 가능하고, 또한 구조가 간단하며 저가격으로 실현이 가능하다는 장점을 가진다 . 본 논문에서 제안된 방법의 타당성을 설계예시를 통해 고찰한 결과, 설계된 디지털 필터의 근사오차와 군지연특성이 동일한 설계사양으로 연속계수공간에서 설계되어진 디지털필터와 비교하여 유사한 결과를 얻을 수 있었다.

• 한국의류산업학회지
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• 제14권4호
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• pp.635-640
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• 2012

In this study, thermoplastic urethane (TPU) coating yarns were prepared at various extruding temperatures. The fine structure and mechanical properties of resultant TPU coating yarns examined by the wide angle X-ray diffractometer (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile test. TPU coating yarns (prepared at extruding temperatures at $175^{\circ}C$) were confirmed as a stable fine structure that obtained excellent tensile strength and flexibility. The C samples prepared by optimized conditions made by TPU woven floor mat. The structure of the woven mat is $4{\times}4$ basket weave and have laminated with the EVA foam to obtained final TPU woven floor mat products. The resultant TPU woven floor mat was obtained to 1.5MN of tensile strength, 22% of the elongation, and 0.2MN of tear strength. The weight loss abrasion and the resilience by the ball rebound of the TPU-woven floor mat was prior to those of the PVC subsequently, we were able to develop a woven floor mat with TPU coating yarn and produce an eco-friendly high valuable woven floor mat using an interior product.

• International Journal of Industrial Entomology and Biomaterials
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• 제40권1호
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• pp.28-32
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• 2020

Recently, many studies have been undertaken on the wet spinning and electrospinning of silk because wet-spun fibers and electrospun webs of silk can be applied in the biomedical and cosmetic fields owing to the good biocompatibility of silk. The rheological properties of silk solution are important because they strongly affect the spinning performance of the silk solution and the structures of resultant fibrous materials. Therefore, as a preliminary study on the effect of solvent composition on the rheological properties of silk fibroin (SF) solution and structure of the resultant film, in the reported work, methanol was added to the SF formic acid solution. A small amount of methanol (i.e. 2%) added to the SF formic acid solution significantly altered the rheological properties of the solution: its shear viscosity increased by 10 folds at low shear and decreased on increasing the shear rate, demonstrating shear thinning behavior of the SF solution. Dynamic tests for the SF solution indicated that the addition of 2% methanol altered the viscous state of the SF formic acid solution to elastic. However, the molecular conformation (i.e. β-sheet conformation) of the regenerated SF film cast from formic acid remained unchanged on the addition of 2% methanol.