• Earthquakes and Structures
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• 제9권3호
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• pp.603-623
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• 2015

The scale and nature of the recent earthquakes in the world and the related earthquake disaster index coerce the concerned community to become anxious about it. Therefore, it is crucial that seismic lateral load effect will be appropriately considered in structural design. Application of seismic isolation system stands as a consistent alternative against this hazard. The objective of the study is to evaluate the structural and economic feasibility of reinforced concrete (RC) buildings with base isolation located in medium risk seismic region. Linear and nonlinear dynamic analyses as well as linear static analysis under site-specific bi-directional seismic excitation have been carried out for both fixed based (FB) and base isolated (BI) buildings in the present study. The superstructure and base of buildings are modeled in a 3D finite element model by consistent mass approach having six degrees of freedom at each node. The floor slabs are simulated as rigid diaphragms. Lead rubber bearing (LRB) and High damping rubber bearing (HDRB) are used as isolation device. Change of structural behaviors and savings in construction costing are evaluated. The study shows that for low to medium rise buildings, isolators can reduce muscular amount of base shears, base moments and floor accelerations for building at soft to medium stiff soil. Allowable higher horizontal displacement induces structural flexibility. Though incorporating isolator increases the outlay, overall structural cost may be reduced. The application of base isolation system confirms a potential to be used as a viable solution in economic building design.

• Advances in robotics research
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• 제2권1호
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• pp.45-57
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• 2018

Even though the popularity of projection mapping continues to increase and it is being implemented in more and more settings, most current projection mapping systems are limited to special purposes, such as outdoor events, live theater and musical performances. This lack of versatility arises from the large number of projectors needed and their proper calibration. Furthermore, we cannot change the positions and poses of projectors, or their projection targets, after the projectors have been calibrated. To overcome these problems, we propose a projection mapping method using a projector robot that can perform projection mapping in more general or ubiquitous situations, such as shopping malls. We can estimate a projector's position and pose with the robot's self-localization sensors, but the accuracy of this approach remains inadequate for projection mapping. Consequently, the proposed method solves this problem by combining self-localization by robot sensors with position and pose estimation of projection targets based on a 3D model. We first obtain the projection target's 3D model and then use it to accurately estimate the target's position and pose and thus achieve accurate projection mapping with a projector robot. In addition, our proposed method performs accurate projection mapping even after a projection target has been moved, which often occur in shopping malls. In this paper, we employ Ubiquitous Display (UD), which we are researching as a projector robot, to experimentally evaluate the effectiveness of the proposed method.

• 한국환경과학회지
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• 제7권2호
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• pp.141-148
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• 1998

Effects of alumlnlum(AA), soil pH and calcium(Cal on growth response and heavy metal accumulation and regulation of nitrogen fixation In Melilotus suaveolens seedlings, a biennial legume plant dominating in the disturbed area, were quantitatively analyzed during the growing periods. Accumulation of metals In each organ of M. suaveojens was Increased UC the lowering of pH. Al contents In leaf and root treat- ed with 30ppm Al at pH 4.2 on the 28th day after treatment were 8 and 11 folds higher than those of control, while the contents with 100ppm AA were 21 and 24 folds as compared to control. The significent inhibition in Al contents was induced by 100ppm AA and Ca at pH 6.5. Increased metals inhibited higher at pH 4.2 and the growth inhibition due to Al was reversed by the addition of Ca, suggesting that growth correlates to the pH value. Chlorophyll contents in leaves increased during growth stave were inhibited by Al treatments. The biomass was decreased UD the lowering of pH and the increase of concentrations. 100ppm Ca treatment resulted in 5.1-5.9% increase of the biomass as compared to that of 100ppm Al. Specific nitrogen fuation activities In nodules In the 100ppm Al at pH 4.2 and pH 6.5 were reduced to 35. 2% and 52.2% of control, on the 28th day after treatment, while the combination of Al and Ca induced reduced by 10% as compared to control with the treatment of 100ppm AA at pH 4.2 due to the inhibition bination of 100ppm Al and Ca and lowering of pH.

• 한국안전학회지
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• 제28권1호
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• pp.12-17
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• 2013

Considering the wind power system and the rotor blades which are composed of much technology, the wind power blade would be the most dangerous part because it revolves at high speed and weighs about dozens of tons, if the accident happens. Therefore, the light weight composite materials have been replacing as substitutional materials. The object of this study is to examine the delamination and damage for CFRP/GFRP hybrid composite that is used for strength improvement of a wind power blade. The influence of the initial crack length and fiber orientation for the interlaminar delamination was exposed for the blade safety. Plain woven CFRP instead of GFRP was inserted into the layer of the box spar for improving the strength and blade life. DCB(Double Cantilever Beam) specimen was used for evaluating fracture toughness and damage evaluation of interlaminar delamination. The material used in the experiment is a commercial material known as CF 3327 EPC in plain woven carbon prepreg(Hankuk Carbon Co.) and UD glass fiber prepreg(Hyundai Fiber Co.). From the results, crack growth rate is not so different according to the variation of the initial crack length. Mode I interlamainar fracture toughness of fiber direction $0^{\circ}$ is higher than that of $45^{\circ}$. Interlaminar fracture has an effect on fiber direction and K decreased with lower value according to increasing initial crack length. Also energy release rate fracture toughness was evaluated because CFRP/GFRP hybrid composite with a different thickness is under the mixed mode loading condition. The interlaminar fracture was almost governed by mode I fracture even though the mixed mode.

• 비파괴검사학회지
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• 제23권3호
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• pp.237-245
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• 2003

이방성 복합재료 적층판에서는 섬유의 배열방향에 따라 탄성계수가 변하므로 속도가 섬유의 방향성에 의존하게 된다. 등방성 속도를 기준으로 도달 시간차를 측정하는 전통적인 2차원 음향방출 위치표정 방법을 그대로 적용할 경우 위치표정의 오차가 매우 커지며, 그 과정이 복잡해지는 것을 피할 수 없다. 본 연구에서는 위치표정의 대상이 되는 관심영역(ROI)를 마치 유한요소법에서 사용하는 메쉬(mesh)처럼 적절한 크기의 정사각형 요소로 나눈 뒤, 각각을 가상의 AE 발생원으로 간주하였으며, 모든 요소에 대해 이방성을 고려한 속도를 기준으로 각 센서와의 도달시간차를 구하였다. 실험적인 검증을 위하여 알루미늄 박판 및 복합재료 적층판에 대해 $0^{\circ}$ 부터 $90^{\circ}$까지의 속도를 측정하고 위치표정을 실시함으로써 이방성 적층복합재로 이루어진 실제 구조물에서의 실시간 활용가능성을 확인하였다.

• 한국식품조리과학회지
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• 제21권6호통권90호
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• pp.950-958
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• 2005

The aim of this study was to evaluate the quality characteristics of pound cake made of flour substituted with $\beta$-glucan (3, 6 and $9\%$), which is a functional fuod material produced from Agrobacterium Spp. R259 KCTC 10197BP. A rapid decrease of moisture content during storage at $20^{\circ}C$, $70\%$ relative humidity, was observed in the control while the moisture content in 3 and $6\%$ $\beta$-glucan added pound cake was not decreased until the 12th day of storage. During storage, the hardness of the control cake was increased whereas that of $\beta$-glucan $6\%$ and $9\%$ added pound cake was not changed until the 6th day of storage. The addition of $\beta$-glucan was therefore conflmed to delay the staling of cake. During storage, the Hunter color L ud b values of the crust and crumb colors of the $\beta$-glucan added pound cake were not significantly different from those of the control, although the a value did increase with longer storage. The sensory results showed that the scores of over-all acceptability of the 3 and $6\%$ $\beta$-glucan added pound cake at the 6th day of storage days were higher than that of the control. These study results confirmed that the addition of $\beta$-glucan to pound cake maintained the moisture content and delayed hardness during storage.

• 한국산업정보학회논문지
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• 제13권1호
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• pp.30-36
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• 2008

최근 POC (Point of care)와 같은 의료서비스의 질을 높이기 위한 연구가 많이 진행되고 있다. 서비스의 질을 높이기 위해서는 장비뿐만 아니라 간호사 인력의 확충이 매우 중요하다. 그러나 현재 대한민국의 간호사 인력은 매우 부족하며, OECD 국가 중 최하위를 기록하고 있다. 많은 간호사의 업무중 단순 반복적인 업무를 대체할 경우, 추가적인 인건비 없이도 고급의 간호 인력을 다른 업무에 사용할 수 있다. 수많은 단순 반복적인 간호사 업무 중에는, 본 논문에서는 링거액을 교체하는 업무에 초점을 맞추었다. 그러므로 본 논문에서는 링거의 자동 교체를 위하여, 먼저 링거의 잔량을 검출하는 알고리즘을 구현하였다. 구현된 알고리즘은 실제 현장에 사용할 때 많이 발생할 수 있는 조명 문제의 해결을 위하여 수정된 SQI 알고리즘을 사용하였으며, 이후 간단한 히스토그램 누적 방법을 이용하여 링거의 잔량을 검색하였다. 구현된 알고리즘은 링거 교체에 사용될 수도 있으며, 간호사들에게 경보를 주는 곳에도 사용할 수 있다.

• 한국식품영양과학회지
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• 제35권9호
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• pp.1172-1177
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• 2006

두릅나무과 식물이 당뇨를 유발한 흰쥐의 지질농도 변화에 미치는 영향을 구명하기 위하여 두릅, 오가피, 느릅의 열수추출물(11.42 g raw araliaceae/kg diet)을 급여한 후 streptozotocin(55 mg/kg B.W.)을 1회 복강주사하여 7주간 사육하였다. STZ 투여로 식이섭취량은 증가된 반면 체중은 감소되었는데 두릅, 오가피 및 느릅의 열수추출물 급여시 체중증가량의 변화는 관찰되지 않은 반면 식이섭취량은 억제되었다. 식이효율은 실험식이 중 오가피 열수추출물이 당뇨로 인한 다식증 개선에 효과적이었다. 혈장과 간조직 중의 중성지질, 총콜레스테롤 및 유리콜레스테롤 함량은 당뇨대조군이 정상군에 비하여 유의적으로 증가되었으나 실험식이 급여시 모든 군에서 정상수준으로 회복되었다. 당뇨로 인해 감소된 HDL-콜레스테롤 함량이 두릅나무과 식물 급여시 회복됨으로써 당뇨로 인한 지질대사 이상을 완화시키는데 이들 열수추출물이 효과적일 것으로 생각된다.

• 멤브레인
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• 제31권2호
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• pp.120-132
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• 2021

미생물 연료전지(MFC)는 미생물의 촉매 반응을 이용하여 폐수 등 환경 오염물질을 처리함과 동시에 전기에너지를 생성하는 생물전기화학 장치다. 미생물 연료전지의 주요 성분 중 하나인 양이온 교환막(PEM)은 미생물 연료 전지의 성능에 결정적인 영향을 미치며, 현재 가장 많이 사용되고 있는 양성자교환막은 Nafion이다. Nafion은 우수한 성능을 가지고 있지만, 단가가 높고, 생물오염에 취약하며, 생분해가 불가능하다는 단점이 있다. 따라서 Nafion을 대체하기 위한 새로운 복합막을 개발하고자 하는 시도가 꾸준히 이루어졌다. 본 총설에서는 미생물 연료전지 분야에서 최근 개발된 복합막의 특징과 성능을 고찰하며, 특히 양성자교환막을 중점적으로 다룬다.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.1-8
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• 2021

In Mobile Ad-Hoc Network (MANET) Application, routing protocol is essential to ensure successful data transmission to all nodes. Ad-hoc On-demand Distance Vector (AODV) Protocol is a reactive routing protocol that is mostly used in MANET applications. However, the protocol causes Route Request (RREQ) message flooding issue due to the broadcasting method at the route request stage to find a path to a particular destination, where the RREQ will be rebroadcast if no Request Response (RREP) message is received. A scalable neighbor-based routing (SNBR) protocol was then proposed to overcome the issue. In the SNBR protocol, the RREQ message is only rebroadcast if the number of neighbor nodes less than a certain fix number, known as drop factor. However, since a network always have a dynamic characteristic with a dynamic number of neighbor nodes, the fix drop factor in SNBR protocol could not provide an optimal flooding problem solution in a low dense network environment, where the RREQ message is continuously rebroadcast RREQ message until reach the fix drop factor. To overcome this problem, a new broadcasting method as Dynamic SNBR (DSNBR) is proposed, where the drop factor is determined based on current number of neighbor nodes. This method rebroadcast the extra RREQ messages based on the determined dynamic drop factor. The performance of the proposed DSNBR is evaluated using NS2 and compared with the performance of the existing protocol; AODV and SNBR. Simulation results show that the new routing protocol reduces the routing request overhead, energy consumption, MAC Collision and enhances end-to-end delay, network coverage ratio as a result of reducing the extra route request messages.