• 전자공학회논문지SC
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• 제37권1호
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• pp.1-9
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• 2000

본 논문에서는 파라미터 변동 범위가 유한한 로봇 매니퓰레이터에 대한 출력궤환 강인제어기를 고이득 관측기를 사용하여 설계하였다. 적분제어를 포함하는 제안된 제어기는 이득제한에 따른 추종오차를 개선시키도록 하였다. 관절의 속도 측정치를 사용할 때의 문제점을 개선하기 위하여 고이득 관측기를 사용하였다. 미지의 파라미터 변동 범위에 대한 제한을 받지 않도록 제어기를 구성하였으며 전체 폐루프시스템의 상태궤적의 수렴성을 입증하였다. 제안된 방법을 2-링크 로봇 매니퓰레이터의 궤적제어에 적용하고 시뮬레이션을 통하여 성능을 확인하였다.

• Journal of electromagnetic engineering and science
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• 제18권1호
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• pp.70-72
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• 2018

We propose a microwave signal generation system for brain stimulation. The existing brain stimulation system uses a signal of several tens of kHz, and the magnetic field distribution is wide. Microwave is used to locally limit the distribution of the electromagnetic field and to change the action potential of the cell with less power. The switch modulates the microwave signal to obtain a pulse envelope. The action potential of the cell can be controlled to the excitation/inhibition state by adjusting the repetition frequency. These results are confirmed by measuring the cell potential of the mouse brain.

• Steel and Composite Structures
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• 제26권6호
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• pp.693-703
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• 2018

To better understand the influence of hollow ratio on the hollow concrete-filled circular steel tubular (H-CFT) stub columns under axial compression and to propose the design formula of ultimate bearing capacity for H-CFT stub columns, 3D finite element analysis and laboratory experiments were completed to obtain the load-deformation curves and the failure modes of H-CFT stub columns. The changes of the confinement effect between core concrete and steel tube with different hollow ratios were discussed based on the finite element results. The result shows that the axial stress of concrete and hoop stress of steel tube in H-CFT stub columns are decreased with the increase of hollow ratio. AfteGr the yield of steel, the reduction rate of longitudinal stress and the increase rate of circumferential stress for the steel tube slowed down. The confinement effect from steel tube on concrete also weakened slowly with the increase of hollow ratio. Based on the limit equilibrium method, a simplified formula of ultimate bearing capacity for the axially loaded H-CFT stub columns was proposed. The predicted results showed satisfactory agreement with the experimental and numerical results.

• 한국산업융합학회 논문집
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• 제23권4_1호
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• pp.531-539
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• 2020

When injection mold is repeatedly used for mass production, fatigue phenomenon due to cyclic stress may occur. The surface and interior of structure might be damaged due to cyclic stress or strain. The objective of this study was to analyze failure of SCM435 high-tension bolts connecting upper and lower parts of a three-stage injection molding machine. These bolts have to undergo an accurate heat treatment to prevent the formation of chromium carbide and the action of dynamic stresses. Bolts were fractured by cyclic bending stress in the observation of ratchet marks and beach marks. Damaged specimen showed an acicular microstructure. Impurity was observed. Chromium carbide was observed near the crack origin. Both shape parameters of the Vickers hardness were similar. However, the scale parameter of the damaged specimen was about 20% smaller than that of the as-received specimen. Much degradation occurred in the damaged specimen. Bolts should undergo an accurate heat treatment to prevent the formation of chromium carbide. They must prevent the action of dynamic stresses. Bolts need accurate tightening and accuracy of heat treatment and screws need compression residual stress due to peening.

• 한국중재학회지:중재연구
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• 제22권1호
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• pp.111-130
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• 2012

Judgment on the validity of patents on the subject of an arbitration does not. In other words, the occurrence of patents generated by the administrative action, and such administrative action by an authorized agency may be treated as legitimate until it is canceled. However, recent Supreme Court judgment on novelty and inventive step as well as judgments about the validity of the patent also made possible by the judiciary. This progress even in the mediation of an arbitral award which is premised on the validity of patents can be seen that possible. However, if the arbitration by an arbitrator if possible a certain portion of the limit exists. In other words, the effect of arbitration between the parties is valid. This patent is valid and invalid in arbitration even if the judgment relative to the effect ceases. In addition, the arbitration award and patent invalidation trial is in progress at the same time, if you consequently will reach a different conclusion. This can cause problems of double track. In addition, by extending the critical target recognition and enforcement in other countries can cause problems. Despite these problems, now about the validity of patents that it is possible intervention is necessary to discuss again.

• Steel and Composite Structures
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• 제30권4호
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• pp.337-350
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• 2019

The objective of this paper is to investigate the confinement coefficient of concrete-filled square stainless steel tubular (CFSSST) stub columns under axial loading. A fine finite 3D solid element model was established, which utilized a constitutive model of stainless steel considering the strain-hardening characteristics and a triaxial plastic-damage constitutive model of concrete with features of the parameter certainty under axial compression. The finite element analysis results revealed that the increased ultimate bearing capacity of CFSSST stub columns compared with their carbon steel counterparts was mainly due to that the composite action of CFSSST stub columns is stronger than that of carbon steel counterparts. A further parametric study was carried out based on the verified model, and it was found that the stress contribution of the stainless steel tube is higher than the carbon steel tube. The stress nephogram was simplified reasonably in accordance with the limit state of core concrete and a theoretical formula was proposed to estimate the ultimate bearing capacity of square CFSSST stub columns using superposition method. The predicted results showed satisfactory agreement with both the experimental and FE results. Finally, the comparisons of the experimental and predicted results using the proposed formula and the existing codes were illustrated.

• 대한기계학회논문집
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• 제16권7호
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• pp.1332-1340
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• 1992

본 연구에서는 제어기에 관심을 갖던 기존의 방법에서 탈피해서 포화요소에 촛점을 맞추어 와인드업 현상을 해결하는 방법을 제시하고자 한다. 이 방법은 단입 출력 시스템에서는 역계산방법(back calculation method)과 동일하나 제어기와 보상기 를 분리하여 설계한 후 보상기를 각각의 엑추에이터 앞에 설치함으로써 다입 출력 시 스템에 쉽게 적용될 수 있다는 점에서 새로운 제안이라 할 수 있다. 또한 제어기를 바꾸지 않고도 보상기만을 추가로 설치하여 와인드업을 방지할 수 있으므로 이미 설치 된 시스템에의 적용이 용이함도 특기할 만하다.

• 한국정밀공학회지
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• 제14권3호
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• pp.156-165
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• 1997

In the practical control systems, the dynamic range of actuatiors is limited(or saturated) when actuators are driven by sufficiently large signals. This gives rise to a nonlinearity as a result of actuator saturation. For example, the upper limit is imposed on productive capability by available factory space and capital equipment. Other examples of those kinds of actuator saturations are a maximum torque of the actua- ting motors and a throttle position in an aircraft speed control A saturating actuator may lead not only to a large overshoot during start-up and shut-down, but also to deterioration of the performance due to the uncertainties. That is, the speed of response is decreased and, possibly, the system output may not follow the lalrge reference inputs. The large-overshoot may be accompanied by rest wind-up(or called by integra- tor wind-up) which comes from controllers with integral action in saturation operation regions. Eventually, as the overshoot increases, the system has a limit cycle or becomes oscillatorily unstable. Due to these cir- cumstances, many studies are focused on the stability and robustness of the nonlinear systems with satu- rating actuator in the time-domain as well as in the frequency-domain.

• 산업경영시스템학회지
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• 제41권1호
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• pp.110-117
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• 2018

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called 'preventive maintenance policy.' Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

• 철학연구
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• 제147권
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• pp.59-76
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• 2018

어떤 존재 x를 도덕적 행위자로 만들어주는 조건은 무엇인가? 인공물도 도덕적 행위자일 수 있는가? 도덕적 행위자는 옳고 그름을 판단할 수 있는 이성적 존재로 간주된다. 본 논문에서는 우선 이성적 존재에 대한 조건에 대한 데이빗슨의 입장을 비판적으로 분석하면서, 명제적 태도(propositional attitude)를 가지는 믿음과 그 배경으로서의 믿음들의 연결망은 이성적 존재의 필요조건이 될 수 없음이 논증된다. 그런 뒤에 도덕적 행위자의 조건에 대한 프로케소바(Eva $Proke{\check{s}}ov{\acute{a}}$)의 입장에 대한 분석을 통해서 프로케소바가 제시한 조건들은 단지 피상적인 요소들의 병렬적 나열에 불과함이 밝혀진다. 본 논문에서 도덕적 행위자는 이성적 행위자를 포함하며, 강한 일인칭 시점이 이성적 행위자와 도덕적 행위자의 필요충분조건임이 논증된다. 결론적으로 도덕적 행위자로서의 가능성을 완강하게 부정하는 강한 회의론 대신에 도덕적 행위자의 조건을 제시함으로써 인공물의 행위자 가능성에 잠정적 한계를 설정해주는 온건한 회의론의 밑그림이 제시될 것이다.