• 한국지진공학회논문집
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• 제23권3호
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• pp.183-190
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• 2019

Recent changes in the construction method of piles to minimize noise, along with the development of high-strength reinforcement, have provided an economical high performance RC pile development to compensate for the disadvantages of existing PHC piles. In this study, a methodology for the development of cross - section details of high performance RC piles of various performances is presented by freely applying high strength steel and concrete. This study suggested a technique for calculating bending moments for a given axial force corresponding to the allowable crack widths and this can be used for serviceablity check. In calculating the design shear force, the existing design equation applicable to the rectangular or the I section was modified to be applicable to the hollow circular section. In particular, in the limit state design method, the shear force is calculated in proportion to the axial force, and the procedure for calculating PV diagram is established. Last, the section details are determined through PM diagrams that they have the similar flexural and axial-flexural performances of the PHC pile A, B and C types with a diameter of 500 mm. To facilitate the application of the selected standard sections to the practical tasks, the design PM diagram and design shear forces are proposed in accordance with the strength design method and limit state design method.

• 한국재료학회지
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• 제33권5호
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• pp.205-213
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• 2023

This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the α_𝜓-sin²𝜓 diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin²𝜓 diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm²/㎛. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin²𝜓 diagram appears clearly in the region of sin²𝜓 > 0.5, it is necessary to increase the inclination angle 𝜓 as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering 𝜎₃ in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of 𝜎₃ can be determined as the presence or absence of strain for sin²𝜓≈0.4.

• 한국물환경학회지
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• 제29권2호
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• pp.176-183
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• 2013

The variation of the stable region of arsenic compounds in aqueous environment with temperature has been investigated by constructing the Pourbaix diagram of arsenic at different temperatures. The standard potential corresponding to the boundary between arsenic compounds with different charge valence was estimated to be decreased with temperature, which means the stability of arsenic compound with +5 charge valence increases. The distribution diagram of the most highly oxidized arsenic compound showed that arsenic acid is formed at higher pH and arsenate is generated at lower pH as temperature rises. The aquatic toxicity due to arsenic compounds was considered to be decreased with temperature in the neutral pH condition based on the $LD_T$ value defined in this study.

• 제어로봇시스템학회논문지
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• 제7권11호
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• pp.939-943
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• 2001

PLC(programmable Logic Controller)s essential components of modern automation systems encompassing almost every industry. Ladder Diagrams (LD) have been widely used in the design of such PLC since the LD is suitable for the modeling of the sequential control system. However, the synthesis of LD itself mainly depends on the experience of the industrial engineer, which may results in unstructured or inflexible design. Hence, in this paper, we propose a ladder diagram conversion algorithm which systematically produces LDs for PLCs based on discrete event models to enhance the structured and flexible design mechanism.

• 전기학회논문지
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• 제56권1호
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• pp.174-182
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• 2007

In this paper, we study the influence of infection ratio on gradual reduction of drug dose for the five state HIV infection model that explicitly includes the population of the virus. We first compute all equilibrium points of the model and investigate the stabilities of them. As a result, a bifurcation diagram is obtained which shows a change in the equilibrium points, or in their stability properties, as the drug effect $\eta$ is varied from 0 to 1(alternatively, drug dose is changed from 1 to 0). Based on the bifurcation diagram, we show that the gradual reduction of drug dose can be applied for the treatment of AIDS patients. Moreover, we analyze the influence of the variation of infection ratio on the gradual reduction treatment. Computer simulation results are also presented to validate the proposed results.

• 소성∙가공
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• 제26권3호
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• pp.144-149
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• 2017

In order to characterize the macroscopic mechanical response of ultra-thin (0.1 mm thick) ferritic stainless steel sheet at various loading paths, a crystal plasticity finite element method (CP-FEM) was introduced. The accuracy of the prediction results was validated by comparing with the experimental data. Based on the results, the forming limit diagram (FLD) was predicted using a modified Marchinicak-Kuczinski model coupled to a non-quadratic anisotropic yield function, namely, Yld2000-2d. The predicted FLD was found to be in good agreement with the experimental data.

• 한국정보통신학회논문지
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• 제14권12호
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• pp.2724-2729
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• 2010

본 논문에서는 유한체상의 순차디지털시스템을 구성하는 방법을 제안하였다. 제안한 방법은 유한체의 성질로 부터 유한체상의 모든 원소를 디지트코드로 할당하는 알고리즘을 제안하였고, 유한체상의 순차디지털시스템을 구성하는데 사용하는 T-gate의 동작특성에 대해 논의하였으며, 이를 토대로 궤환이 없는 순차디지털시스템을 구성하였다. 이를 위해 상태천이도를 상태디지트코드로 할당하였고, 상태함수와 현재상태와 이전상태와의 관계를 나타내는 전순표를 도출하였다. 다음에 상태함수와 전순표로부터 다음상태함수를 도출하였으며, 이를 T-gate와 복호기를 시용하여 순차디지털시스템을 구성하였다. 제안한 방법으로 효과적이고 체계적으로 순차디지털시스템을 구성할 수 있었음을 확인하였다.

• 한국광학회지
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• 제19권1호
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• pp.48-53
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• 2008

본 논문에서는 $90^{\circ}$ 꼬인 네마틱 액정 셀에 전계를 인가하지 않았을 때 어두운 상태를 나타내는 normally black 모드 구현 시, 높은 명암비를 제공하는 광학구조를 제안하였다. 제안된 구조에서 +A 필름과 ${\lambda}/2$ 필름을 각각 1 장씩 사용하여 $90^{\circ}$ 꼬인 액정층을 통과한 빛의 가시광 파장대에서 편광 상태가 거의 동일하게 만들어 줌으로써, 어두운 상태의 분광특성을 향상시킬 수 있다. PSD(Parameter Space Diagram) 방법을 사용하여 최적조건을 구해 계산한 결과 500: 1 이상의 높은 명암비를 확보할 수 있었으며, 어두운 상태뿐만 아니라 밝은 상태의 분광특성도 향상됨을 시뮬레이션 및 실험을 통해 확인할 수 있었다.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.65-72
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• 2009

현재 컴포넌트 기반 개발 기법은 재사용성과 생산성 측면에서 효과적인 소프트웨어 개발 방법으로 많은 각광을 받고 있다. 하지만 기존의 UML을 이용한 컴포넌트 기반 개발에서는 컴포넌트의 행위를 배제하고 컴포넌트 인터페이스만 참조하여 컴포넌트를 설계함으로써, 컴포넌트의 구체적인 행위에 대한 파악과 컴포넌트 간 인터페이스 호환성 보장이 불가능하다. 이에 따라 컴포넌트 설계 단계에서 컴포넌트의 행위를 상태기계 다이어그램으로 표현하고, 표현된 상태기계 다이어그램을 통해 컴포넌트의 행위 호환성을 보장할 필요가 있다. 이 연구에서는 상태기계 다이어그램으로 표현된 컴포넌트의 행위를 관찰 일치(observation equivalence)와 호출 일관성(invocation consistency)의 개념을 이용하여 행위 호환성을 검증하는 방법을 제공하고, 동적으로 이를 수행하는 도구를 개발한다.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1821-1834
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• 2017

Medium voltage control applications due to obtain better output voltage and reduced electro-magnetic interference multi level inverter is used. In closed loop control with inverter, the PI controller does not operate satisfactorily when the operating point changes. This paper presents the performance of Co-Efficient diagram PI controller based indirect vector controlled induction motor drive fed from three-level inverter under different operating conditions (dynamic and steady state). The proposed Co-Efficient diagram PI controller based three level inverter significantly reduces the torque ripple compared to that of conventional PI controller. The performance of the indirect vector controlled induction motor drive has been simulated at different operating conditions. For three-level inverter control, a simplified space vector modulation technique is implemented, which reduces the coordinate transformations complications in the algorithms. The performance parameters, torque ripple contents and THD of induction motor drive with three-level inverter is compared under different operating conditions using CDM-PI and conventional PI controllers.