• Journal of Ginseng Research
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• 제31권2호
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• pp.74-78
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• 2007

Multi-drug resistance (MDR) is a major problem in cancer chemotherapy and has often ended up with termination of the therapy. The aim of this study was to identify any fractions of Korean red ginseng that would be effective in modulating for MDR. Although ginsenosides have been reviewed as possible MDR modulators, the MDR modulation activity of the other component is unknown. Therefore, a red ginseng was extracted with methanol, ether, ethylacetate, and n-butanol, followed by several fractionations by silica gel chromatography. And the activity of MDR modulating for these fractions was examined via sulforrhodamine B assay. We have found that several ether fractions, as nonsaponin components are effective on MDR modulation. We have expect that these results helpful to improvement of cancer chemotherapy.

• Structural Engineering and Mechanics
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• 제43권1호
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• pp.71-87
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• 2012

This paper extends a single equation, semi-analytical approach for three-span bridges to multi-span ones for the rapid and precise determination of natural frequencies and natural mode shapes of an orthotropic, multi-span plate. This method can be used to study the dynamic interaction between bridges and vehicles. It is based on the modal superposition method taking into account intermodal coupling to determine natural frequencies and mode shapes of a bridge deck. In this paper, a four- and a five-span orthotropic roadway bridge deck are compared in the first 10 modes with a finite element method analysis using ANSYS software. This simplified implementation matches numerical modeling within 2% in all cases. This paper verifies that applicability of a single formula approach as a simpler alternative to finite element modeling.

• 소성∙가공
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• 제28권5호
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• pp.275-280
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• 2019

The aim of this study is to fabricate an ultra-fine pure rhodium wire using multi-pass wire drawing process. To manufacture $30{\mu}m$ ultra-fine rhodium wire from the initial $50{\mu}m$ wire, a multi-pass wire drawing process was designed based on the uniform reduction ratio theory. The elastic-plastic finite element analysis was then conducted to validate the efficacy of the designed process. The drawing load, drawing stress, and the distribution of the effective strain were evaluated using the finite element analysis. Finally, the wire drawing experiment was performed to validate the designed wire drawing process. From the results of the experiment, the diameter of the final drawn wire was found to be $29.85{\mu}m$.

• 생명과학회지
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• 제18권11호
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• pp.1532-1537
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• 2008

무릎인공관절 단축범위 수술자와 다축범위 수술자를 대상으로 영상분석과 근전도 분석 그리고 운동생리학적 분석을 통하여 얻은 결과는 다음과 같다. 한 계단 오르기와 내리기 동안 소요시간은 대상자들 간에 통계적으로 큰 차이(p=0.380, p=0.171)는 없었지만 평균에서는 약간의 차이가 나타났다. 단 축범위 수술자가 다축범위 수술자보다 오르기와 내리기에서 평균속도가 빠른 것으로 나타났다. 한 계단 오르기 동안 고관절의 각속도, 무릎의 각속도, 발목의 각속도는 세 관절 모두 통계적으로는 유의한 차이(p=0.078, p=0.095, p=0.069)는 없었지만 평균의 비교에서는 단축관절 수술자가 다축관절 수술자보다 빠르게 나타났다. 한 계단 오르기 동안 관절의 최대 토크는 통계적으로 차이(p=0.052, p=0.096, p=0.134)는 나타나지 않았으나 평균의 비교에서는 단축관절 수술자가 다축관절의 수술자보다 각관절의 토큐가 모두 크게 나타났다. 굴곡과 신전으로만 움직이게 단축으로 제작된 인공관절에서는 볼 수 없는 변인으로서 연구의 의미가 있다고 사료된다. 계단 오르기와 내리기 동안 외전과 내전이 일어나는 각도를 알아본 결과 통계적으로는 큰 차이는 없었으나(p=0.103) 계단 오르기 동작 ($6.2^{\circ},\;7.8^{\circ}$)이 내리기 동작($5.8^{\circ},6.4^{\circ}$)보다 약간 크게 나타났다. 다축범위 수술자와 단축범위 수술자의 등장성 수축 시 하지의 근육변화를 알아보기 위하여 $15^{\circ}-75^{\circ}$ 사이의 무릎을 펴는 동안 VM, VL, RF, BF, ST의 근육들의 EMG값을 비교해본 결과 통계적으로 유의한 차이(P<0.05)가 나타났다. Table 5에서 보면 다축범위 수술자와 단축범위 수술자간에 대퇴사두근과 무릎오금근에서 유의한 차이(p<0.05, p<0.01)를 나타내고 있다. 무릎을 펴는 등장성 수축 동작에서 VM EMG값은 단축범위 수술자가 다축범위 수술자보다 $31^{\circ}-45^{\circ}$ 그리고 $61^{\circ}-75^{\circ}$에서 더욱 크게 나타났다. BF EMG값은 모든 구간에서 단축범위 수술자가 다축범위 수술자보다 크게 나타났다. 서로 다른 4그룹에서 운동 강도별 피험자의 체지방율의 변화는 젊은 일반군(C), 노인군(E), 단축범위 수술자(S), 다축범위 수술자(M) 에서 운동시기별 측정값의 통계적 유의한 차이는 나타나지 않았으나, C 그룹에서 시기별 체지방률이 감소하였고, 고강도 운동인 HI 시기에 가장 낮은 값을 나타내었다. 반면에 E, S 및 M 그룹에서는 시기별 감소하는 경향은 있었으나, 증가된 곳도 있고 HI 시기에서는 모든 그룹에서 감소하였다. 하지만 모든 시기에서 통계적인 차이를 나타내지 않았다. 서로 다른 4그룹에서 운동강도별 피험자의 안정시대사량의 변화는 그룹별 용이한 비교를 위하여 체표면적으로 나눈 값으로 표기하였다. C 그룹에서 시기별 안정 시 대사량 값이 증가하여 저강도 운동 후 가장높은 값을 보였고 통계적으로도 유의하게 증가함을 알 수 있었다(p<0.05). 서로 다른 4그룹에서 운동 강도별 피험자의 평균에너지 지출량의 변화는 운동 중과 운동 후 30분간의 에너지 지출량의 평균값을 나타낸 것으로 시기별 C 그룹에 대하여 다른 그룹을 비교 하였다. 우선 고강도 운동 시 C 그룹에 비해 E, S, M 그룹에서 낮은 에너지 소비량 값을 보였고, 모든 그룹에서 통계적으로 낮은 값을 보였다(p<0.05). 그리고 이러한 결과는 저 강도 운동에서도 같은 경향을 보이며 나타났는데, 저강도 운동 시 평균 에너지 지출량은 C그룹에 비하여 E, S, M 그룹에서 낮은 에너지 소비량 값을 보였다. 무릎인공관절 단축범위 수술자와 다축범위 수술자를 대상으로 운동역학적인 변인과 운동생리학적 변인을 동시에 병행하여 연구를 시도한 결과 우선 실험상의 어려움들이 많이 나타났다. 현재는 인공관절 수술이 두 종류의 형태뿐만 아니라 재료가 다른 여러 종류의 인공관절도 제작되고 있다. 계속적으로 추가적인 연구가 실시되어야 할 것으로 사료된다.

• 아동학회지
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• 제31권6호
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• pp.35-50
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• 2010

Joint attention, language development, and the relationship between these two variables were compared in infants from multi-cultural and Korean families. Joint attention was observed in both the Early Social Communication Scale (ESCS) and in infant-mother free play. Language development was evaluated by means of the MacArthur-Bates Communicative Development Inventory-Korean. There were no group differences in initiating and responding to joint attention in ESCS. However, in infant-mother free play, joint attention episodes were less and shorter in duration with infants from multi-cultural families than in Korean infants. The size of both the expressive and receptive vocabulary was also smaller in infants from multi-cultural families than in Korean infants. In terms of Korean infants, mean duration of joint attention episodes in free play showed a significant positive correlation with the size of the expressive vocabulary and initiating joint attention in ESCS also showed a significant positive correlation with the size of receptive vocabulary. However, none of the measures of joint attention indicated a significant relationship with the size of either expressive or receptive vocabulary in infants from multi-cultural families.

• 소성∙가공
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• 제24권4호
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• pp.234-240
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• 2015

Multi-pass shape drawing is very important to produce steel profiles in round samples. In the current study, a process design system is developed for a multi-pass shape drawing. In general, the number of passes for a multi-pass shape drawing is 2 to 3 when the reduction ratio, drawing stress, and productivity are considered. Therefore, calculating the drawing stress and designing the intermediated die shapes are very important. In order to calculate the drawing stress, a shape drawing load prediction method is proposed using a general axisymmetric drawing load prediction model. An intermediate die shape design method is proposed using the initial and the final product shapes. Based on this analysis, a process design system is developed for multi-pass shape drawing for steel profiles. The system works with AutoCAD. The system was applied to design a shape drawing of a spline.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권6호
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• pp.309-313
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• 2002

In this paper, we have studied minimization of the kerf-width and surface burning, which occurred after the conventional singulation process of the multi-layer BGA board with copper, polyethylene and epoxy glass fiber. The high thermal energy of a pulsed Nd:YAG laser is used to cut the multi-layer board. The most considerable matter in the laser cutting of the multi-layer BGA boards is their different absorption coefficient to the laser beam and their different heat conductivity. The cut mechanism of a multi-layer BGA board using a 2$^{nd}$ harmonic Nd:YAG laser is the thermal vaporization by high temperature rise based on the Gaussian profile and copper melting point. In this experiment, we found that the sacrifice layer and Na blowing are effective in minimizing the surface burning by the reaction between oxygen in the air and the laser beam. In addition, N2 blowing reduces laser energy loss by debris and suppresses surface oxidation. Also, the beam incidence on the epoxy layer compared to polyimide was much more suitable to reduce damage to polyimide with copper wire for the multi layer BGA singulation. When the polyester double-sided tape is used as a sacrifice layer, surface carbonization becomes less. The SEM, non-contact 3D inspector and high-resolution microscope are used to measure cut line-width and surface morphology.

• Smart Structures and Systems
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• 제33권1호
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• pp.41-53
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• 2024

Grouting sleeves are an essential connecting component of prefabricated components, and the quality of grouting has a significant influence on structural integrity and seismic performance. The embedded grouting sleeve (EGS)'s grouting defects are highly undetectable and random, and no effective monitoring method exists. This paper proposes an ultrasonic guided wave method and provides a set of guidelines for selecting the optimal frequency and suitable period for the EGS. The optimal frequency was determined by considering the group velocity, wave structure, and wave attenuation of the selected mode. Guided waves are prone to multi-modality, modal conversion, energy leakage, and dispersion in the EGS, which is a multi-layer structure. Therefore, a time-reversal (TR)-based multi-mode focusing and dispersion automatic compensation technology is introduced to eliminate the multi-mode phase difference in the EGS. First, the influence of defects on guided waves is analyzed according to the TR coefficient. Second, two major types of damage indicators, namely, the time domain and the wavelet packet energy, are constructed according to the influence method. The constructed wavelet packet energy indicator is more sensitive to the changes of defecting than the conventional time-domain similarity indicator. Both numerical and experimental results show that the proposed method is feasible and beneficial for the detection and quantitative estimation of the grouting defects of the EGS.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.170-175
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• 1998

Transporting a large table using multiple robotic agents requires at least two group behaviors of homing and herding which are to bo coordinated in a proper sequence. Existing GP methods for multi-agent learning are not practical enough to find an optimal solution in this domain. To evolve this kind of complex cooperative behavior we use a novel method called fitness switching. This method maintains a pool of basis fitness functions each of which corresponds to a primitive group behavior. The basis functions are then progressively combined into more complex fitness functions to co-evolve more complex behavior. The performance of the presented method is compared with that of two conventional methods. Experimental results show that coevolutionary fitness switching provides an effective mechanism for evolving complex emergent behavior which may not be solved by simple genetic programming.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.352-357
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• 1998

Conventional marketing research generally focuses on a single layer's benefit. A notable example is the consumer layer providing managers with partial market information to evaluate relevant strategies. As generally known, marketing management encounters complex supply and demand behaviors, thereby necessitation that a successful marketing strategy adopt multi-layer considerations, such as the consumer layer, channel-retailer layer, and marketing planner layer. In light of above situation, this study applies fuzzy theory and the analytic hierarchy process(AHP) technique to analyze the performances of marketing strategies under multi-layer benefits, In addition, conventional marketing research has difficulty in efficiently allocating the limited budget so that each desired criterion can be significantly enhanced by a group of events. Therefore, a weighting structure among the goal, layers, criteria, and strategies(i.e. a group of events) is also developed herein to trace the influential process and assist marketing managers in efficiently allocating resources(i.e.budget).