• Computers and Concrete
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• 제22권2호
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• pp.209-220
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• 2018

In order to evaluate the effect of hybrid fibers on the flexural performance of tunnel segment at room temperature, twelve reinforced self-consolidating concrete (SCC) symmetric inclination beams containing steel fiber, macro polypropylene fiber, micro polypropylene fiber, and their hybridizations were studied under combined loading of flexure and axial compression. The results indicate that the addition of mono steel fiber and hybrid fibers can enhance the ultimate bearing capacity and cracking behavior of tested beams. These improvements can be further enhanced along with increasing the content of steel fiber and macro PP fiber, but reduced with the increase of the reinforcement ratio of beams. The hybrid effect of steel fiber and macro PP fiber was the most obvious. However, the addition of micro PP fibers led to a degradation to the flexural performance of reinforced beams at room temperature. Meanwhile, the hybrid use of steel fiber and micro polypropylene fiber didn't present an obvious improvement to SCC beams. Compared to micro polypropylene fiber, the macro polypropylene fiber plays a more prominent role on affecting the structural behavior of SCC beams. A calculation method for ultimate bearing capacity of flexural SCC symmetric inclination beams at room temperature by taking appropriate effect of hybrid fibers into consideration was proposed. The prediction results using the proposed model are compared with the experimental data in this study and other literature. The results indicate that the proposed model can estimate the ultimate bearing capacity of SCC symmetric inclination beams containing hybrid fibers subjected to combined action of flexure and axial compression at room temperature.

• International Journal of Concrete Structures and Materials
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• 제10권3호
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• pp.325-335
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• 2016

This paper studies the effects of steel fibre geometry and architecture on the cracking behaviour of steel fibre reinforced concrete (SFRC), with the reinforcements being four types, namely 5DH ($Dramix^{(R)}$ hooked-end), 4DH, 3DH-60 and 3DH-35, of various hooked-end steel fibres at the fibre dosage of 40 and $80kg/m^3$. The test results show that the addition of steel fibres have little effect on the workability and compressive strength of SFRC, but the ultimate tensile loads, post-cracking behaviour, residual strength and the fracture energy of SFRC are closely related to the shapes of fibres which all increased with increasing fibre content. Results also revealed that the residual tensile strength is significantly influenced by the anchorage strength rather than the number of the fibres counted on the fracture surface. The 5DH steel fibre reinforced concretes have behaved in a manner of multiple crackings and more ductile compared to 3DH and 4DH ones, and the end-hooks of 4DH and 5DH fibres partially deformed in steel fibre reinforced self-compacting concrete (SFR-SCC). In practice, 5DH fibres should be used for reinforcing high or ultra-high performance matrixes to fully utilize their high mechanical anchorage.

• 한국자동차공학회논문집
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• 제24권1호
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• pp.16-23
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• 2016

The EWB(electronic wedge brake) is one in which the braking force is developed in a wedge and caliper system and applied to a disk and wedge mechanism. The advantage of the wedge structure is that it produces self-reinforcing effect and hence, utilizes minimal motor power, resulting in reduced gear and current. The extent of use of clamping force sensors and protection from failure of the EWB system directly depends on the level of vehicle mass production. This study investigated the mathematical equations, simulation modeling, and failsafe control algorithm for the clamping force sensor of the EWB and validated the simulations. As this EWB system modeling can be applied to motor inductance, resistance, screw inertia, stiffness, and wedge mass and angle, this study could improve the accuracy of simulation of the EWB. The simulation results demonstrated the braking force, motor speed, and current of the EWB system when the driver desired to the step and pulse the brake force inputs. Moreover, this paper demonstrated that the proposed failsafe control algorithm accurately detects faults in the clamping force sensor, if any.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.125-128
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• 2007

The problem of water leakage due to damaging waterproof in concrete structure, causes the impediment in a long term and shortened the life span of durability. There are a lot of techniques for repair and reinforcement to improve using environment. However, the improper construction which is unconsidered various environmental conditions, could effect to increase the maintenance expenses. Therefore, this study will be compared and estimated the adhesion liquid and sheet integrate waterproofing material, as analyzing the existing problem. For those result, we would like to arrange the alterative plan for the long durability and user needs of concrete structure.

• Advances in concrete construction
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• 제1권1호
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• pp.65-84
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• 2013

Electrical resistivity is a property associated with both the physical and chemical characteristics of concrete. It allows the evaluation of the greater or lesser difficulty with which aggressive substances penetrate the concrete's core before the dissolution of the passive film process and the consequent reinforcement's corrosion begin. This work addresses the capillary absorption of self-compacting concrete (SCC) with various types and contents of additions, correlating it with its electrical resistivity. To that effect, binary and ternary mixes of SCC were produced using fly ashes (FA) and limestone filler (LF). A total of 11 self-compactable mixes were produced: one with cement (C) only; three with C + FA in 30%, 60% and 70% substitution ratios; three with C + LF in 30%, 60% and 70% substitution ratios; four with C + FA + LF in combinations of 10-20%, 20-10%, 20-40% and 40-20% substitution ratios, respectively; and four reference mixes according to the LNEC E 464 specification, which refers to the NP EN 206-1 norm. The evaluation of the capillarity of the mixes produced was made through the determination of the water absorption by capillarity coefficient according to the LNEC E 393 specification. The electrical resistivity was evaluated using the European norm proposal presented by the EU-Project CHLORTEST (EU funded research Project under 5FP GROWTH programme) and based on the RILEM TC-154 EMC technical recommendation. The results indicate that SCC's capillarity is strongly conditioned by the type and quantity of the additions used. It was found that FA addition significantly improves some of the properties studied especially at older ages.

• 정보처리학회논문지B
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• 제12B권7호
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• pp.811-822
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• 2005

자동문서분류는 문서의 내용에 기반하여 미리 정의된 항목에 자동으로 할당하는 작업으로서 효율적인 정보관리 및 검색등에 필수적인 작업이다. 기존의 문서분류성능 향상을 위한 연구들은 대부분 분류모델 자체를 개선시키는 데 주력해왔으며 통계적인 방법으로 그 범위가 제한되어왔다. 본 연구에서는 자동문서분류의 성능향상을 위해 데이터마이닝 기법과 결함허용방법을 이용하는 개선된 학습알고리즘과 후처 리 방법에 의한 RTPost 시스템을 제안한다. RTPost 시스템은 학습문서 선택작업 이전에 분류항목 설정의 문제를 다루며, 분류함수의 성능보다는 지정방식의 문제점을 감안하여 학습과 분류 후처리 프로세스를 개선하려는 것이다. 이를 통해 분류결과에 중요한 영향을 미쳐왔던 학습문서의 수와 선택방법, 분류모델의 성능등에 의존하지 않는 안정적인 분류가 가능하였고, 이를 분류오류율이 높은 경계선 인접영역에 위치한 문서들에 적용한 결과 높은 정확율을 얻을 수 있었다. 뿐만 아니라, RTPost 프로세스를 진행하는 동안 능동학습방법의 장점을 수용하여 학습효과는 높이며 비용을 감소시킬 수 있는 자가학습방법(self learning)방법의 효과를 기대할 수 있다.

• 부모자녀건강학회지
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• 제8권1호
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• pp.37-48
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• 2005

Purpose: The purpose of this study was to develop a play education program to reduce children's fear of needle insertion to the implanted port, and to assess the effect of this program. Method: The play education program was composed of play education before needle insertion, encouragement during needle insertion, and a present to reward then after needle insertion. Measurement instruments were the Procedure Behavior Check List(PBCL) and Faces Rating Scale(FRS). Results: The first hypothesis, "the PBCL point of children with malignant disease would decrease after play education program", was rejected(before insertion : Z=-0.189, p= .850, during insertion : Z=-0.350. p= .727, after insertion : Z=-0.590, p= .555). The second hypothesis, "the FRS point of children with malignant disease would decrease after play education program education", was rejected(observer 1 : Z=-0.245, p= .806, observer 2 : Z=-0.912, p= .362, self-report : Z=-0.181, p= .856). The third hypothesis, "the Time of needle insertion would decrease after play education program", was rejected(Z=-0.464, p= .642). Conclusion: The effect on fear-reduction of play education program for children with malignant disease inserted implanted port was not significant but continuous education is needed for parents and children.

• Journal of Ginseng Research
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• 제46권1호
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• pp.147-155
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• 2022

Background: Methamphetamine (METH) is the most widely used psychostimulant and has been known to exhibit reinforcing effects even after long abstinence. We showed the inhibitory effect of Korean Red Ginseng extract (RGE) on METH-induced addictive behaviors in animal models mimicking the human drug-use pattern. Methods: We first investigated the effect of RGE on the acquisition of METH-induced dependence using self-administration and conditioned place preference (CPP) tests. Additionally, further experiments such as METH-induced motivational behavior and seeking behavior were conducted. To study the underlying mechanism, dopamine receptor, dopamine transporter, and N-methyl-D-aspartate receptor were assessed through Western blot analysis. Results: Treatment with RGE significantly reduced METH-induced self-administration on a fixed-ratio 1 schedule of reinforcement. It could be also decreased a progressive ratio schedule, and inhibited METH-primed reinstatement. In CPP, RGE significantly prevented the development of METH-induced CPP. Moreover, RGE not only shortened the withdrawal period clearly, but also prevented the reinstatement of CPP. RGE treatment also reversed METH-induced overexpression of dopamine transporter, dopamine receptor D1, and NMDA receptor in the nucleus accumbens. Conclusion: Our findings reflect that RGE has therapeutic potential to suppress METH-induced addictive behaviors by regulating dopaminergic and NMDAergic system.

• 한국콘텐츠학회논문지
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• 제12권1호
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• pp.234-243
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• 2012

본 연구는 국내 최초로 배우를 대상으로 무대불안을 극복하기 위한 체계적인 심리기술훈련 프로그램을 구성하고, 이를 바탕으로 심리상담을 실시하여 그 현장 적용의 가능성과 효과성을 분석하고자 하였다. 이를 위해 직업극단 연기자로 활동하고 있는 배우 2명을 목적적 표본추출법으로 선정하였다. 심리기술훈련 프로그램을 크게 5단계 12회기로 구성하였으며, 기초 교육, 호흡 조절법, 점진적 이완법, 집단상담, 심박수 바이오피드백훈련, 자기집중훈련, 루틴훈련, 행동수정 및 자기강화훈련, 심상훈련 등으로 내용화되었다. 무대불안 극복을 위한 심리기술훈련과 상담을 적용한 결과, 신체적 인지적 상태불안요인 모두 훈련 적용 전보다는 긍정적인 변화를 보였으며, 내적 변화 역시 긍정적으로 유발되어 무대불안을 극복하는데 도움을 준 것으로 나타났다. 또한 배우의 자기발견, 배우와 배우간의 앙상블, 배우와 관객 사이의 교감 증진에 긍정적인 변화가 있었다. 결론적으로 배우의 무대불안 극복을 위한 심리기술훈련 및 상담은 현장 적용성과 효과성이 있는 것으로 나타났다.

• 한국콘텐츠학회논문지
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• 제8권6호
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• pp.130-139
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• 2008

본 연구는 국내 최초로 배우를 대상으로 무대불안을 극복하기 위한 체계적인 심리기술훈련 프로그램을 구성하고, 이를 바탕으로 심리상담을 실시하여 그 현장 적용의 가능성과 효과성을 분석하고자 하였다. 이를 위해 직업극단 연기자로 활동하고 있는 배우 2명을 목적적 표본추출법으로 선정하였다. 심리기술훈련 프로그램을 크게 5단계 12회기로 구성하였으며, 기초 교육, 호흡 조절법, 점진적 이완법, 집단상담, 심박수 바이오피드백훈련, 자기집중훈련, 루틴훈련, 행동수정 및 자기강화훈련, 심상훈련 등으로 내용화되었다. 무대불안 극복을 위한 심리기술훈련과 상담을 적용한 결과, 신체적 인지적 상태불안요인 모두 훈련 적용전보다는 긍정적인 변화를 보였으며, 내적 변화 역시 긍정적으로 유발되어 무대불안을 극복하는데 도움을 준 것으로 나타났다. 또한 배우의 자기발견, 배우와 배우간의 앙상블, 배우와 관객 사이의 교감 증진에 긍정적인 변화가 있었다. 결론적으로 배우의 무대불안 극복을 위한 심리기술훈련 및 상담은 현장 적용성과 효과성이 있는 것으로 나타났다.