• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.261-262
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• 2016

본 논문에서는 계기용변압기(Potential Transformer, PT) 1차권선의 절연내력을 향상시키기 위하여 전위분포가 일정하게 되도록 권선 배치를 최적화하는 프로그램을 작성하여 반복 분석하였다. 우선 기존의 권선 배치에 대한 국소점의 전계분포를 고찰하여 전계의 최대치를 구한 후, 권선 배치를 자동화된 순환 계산형 시뮬레이터를 제작하여 적절한 분포로 교정하고 최초의 기대 함수치를 극소화하는 형상을 반복 추적하는 알고리즘을 이용하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.188-193
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• 1993

In widening of existing bridges, construction joints between old new parts of concrete slabs are subjected to repeated traffic loads during placing and curing of concrete. Therefore, the main focus of this paper is given to examine several construction methods of bridge widening. As a result, the occurrence of cracks in vibrating specimen is faster than non-vibrating one, but the difference between flexural strength and ultimate moment was negligible. Also, it shows the same result in other construction method, say direct and non-shrinkage joint specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.953-958
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• 2001

A retrofit method “Steel Ring Confinement Retrofit” was proposed and discussed on the material and member characteristics through experiments. Steel Ring Confinement Retrofit consist of confining steel ring and expansive concrete. The steel ring is set on the footing, surrounding the base of the pier. By placing expansive concrete between the pier and steel ring, chemical prestress is introduced in the members. Chemical prestressed ring concrete enlarge the pier section and enhance both the strength and ductility of the pier. It was confirmed that Various Ring Confinement Retrofit improved the strength of the pier up to 30% ~ 100% with experiments.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.441-456
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• 2005

The purpose of this paper is to introduce the concept of negative DEA, which aims at identifying worst performers by placing them on the efficient frontier, This paper also proposes to use a layering technique instead of the traditional cut-off point approach, since this enables incorporation of risk attitudes and risk-based pricing. The results of the empirical application on credit risk evaluation validate the method which is proposed in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1209-1213
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• 1991

This paper describes a new method for performance improvement ultrasonic ranging system using V40 controller. Detectable range of ultrasonic ranging system depends on transducer frequency and bandwidth of the receiver, and damping of the transducer, etc. Conventional ranging systems are somewhat inaccurate because they do not have capability of compensating changes in medium condition. The novel ranging system overcomes this disadvantage by placing in the same medium a dummy sensor functioning as a standard calibrating instrument and by providing data processing capability using V40 controller.

• Korean Journal of Cleft Lip And Palate
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• v.16 no.1
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• pp.19-23
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• 2013

Maxilla protraction, orthopedic correction of deficient maxilla is necessary for treatment of most Class III growing patients. Protraction method has evolved from tooth-born appliance to miniplates on the maxilla, and from face mask to miniplates on the chin. By placing miniplates on the maxilla and the mandible and running elastics between them, we can minimize dentoalveolar relapse and maximize orthopedic change.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.25-26
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• 2022

The purpose of this study is to prevent serious disasters in cold weather by presenting an optimal blending design for securing high early strength when placing concrete by analyzing the properties and compressive strength of concrete formulations using high early strength admixture materials.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.639-642
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• 1999

Pullout test known as Lok test among the test methods to evaluate concrete strength strength is a test method which is used to decide the form removal time by assessing the early strength of concrete in a new construction, or to control the quality of newly placed concrete. This method has inconvenience to place inserts on the form work in advance, however, the placing work is quite simple and it has advantage that the strength can be measured at field as long as the inserts are placed. In this study, the first step is to investigate the properties of test method itself, by performing the laboratory test which covers deviation of the method and factors affecting the results, etc. The second step is to correlate the result with cylinder strength and other NDT methods such as rebound hammer, ultrasonic method, etc. And that, the results are compared with foreign results to find the differences between the two. In this research, new factors such as moisture content, area of aggregate failure cross section and area of aggregate separation cross section, etc as well as wate-cement ratio and age are investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.335-342
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• 2001

In this paper, an improved Element-Free Galerkin (EFG) method is proposed by adding enrichment function to the standard EFG approximation and a discontinuity function is implemented in constructing the shape function across the crack surface. In this method, the singularity and the discontinuity of the crack are efficiently modeled by using initial node distribution to evaluate reliable stress intensity factor, though the standard EFG method requires placing additional nodes near the crack tip. The proposed method enables the initial node distribution to be kept without any additional nodal d.o.f. and expresses the asymptotic stress field near the crack tip successfully. Numerical example verifies the improvement and the effectiveness of the method.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.13-18
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• 1994

Most widened bridges have been constructed by the joining-construction method that makes new and existing bridge structurally single structure. However, joing-construction method has several problems in design and construction viewpoint. Therefore, this study is conducted in order to investigate structural behavior of widened RC slab and traffic-induced vibration of existing bridge during placing and curing of new concrete by the prototype flexural fatigue test. From the results of this study, it is shown that stress-concentration and slip occur between concrete and reinforcing rod at joint section but the reduction of load carrying capacity and of fatigue strength is negligible according to the traffic-induced vibration as well as the difference of construction method. A reasonable construction method for the bridge widening which takes into account the effects of the traffic-induced vibration and S-N curve for the widened bridge are also proposed.