• Proceedings of the Korean System Dynamics Society
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• 2000.02a
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• pp.97-114
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• 2000

시스템 다이내믹스 연구에 있어서 피드백 루프는 시스템의 구조와 행태를 연결시키는 핵심적인 개념적 도구이다. 특히 여러 개의 피드백 루프로 구성된 복잡한 시스템에 있어서, 지배적 피드백 루프(dominant feedback loop) 및 그 전환(shift)은 시스템의 행태를 결정짓는 구조적 원인을 제공한다. 그러나 지배적 피드백 루프에 대한 연구는 아직까지 그 발견방법에 관한 알고리즘 연구에 머물러 있는 상태이다. 지배적 피드백 루프는 시스템의 급격한 변화를 예상하는 단초가 된다는 점에서, 지배적 피드백 루프를 어떻게 인식할 것이냐는 정부의 정책결정에 있어서나 기업의 의사결정에 있어서 중요한 문제라고 할 수 있다. 본 논문에서는 지배적 피드백 루프 및 그 전환에 대한 의사결정자의 인식에 관하여 살펴보고 어떠한 인지적 편향이 있는지에 관하여 검토하고자 한다.

• Proceedings of the Korean System Dynamics Society
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• 2000.07a
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• pp.135-152
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• 2000

지배적 피드백 루프는 구조가 시스템의 행동을 유발한다는 점에 있어서 매우 중요한 개념이다. 본 논문에서는 지배적 피드백 루프의 전환을 완만한 전환(continuous shifts)과 급격한 전환(discrete shifts)의 두 가지로 분류하였다. 본 연구에서는 지배적 피드백 루프의 전환에 대한 인지적 편향을 세 가지의 가설로 분류하여 제시하였다. 이에는 1) 완만한 전환에 대한 인식의 실패, 2) 의사결정 자들의 급격한 전환에 의존하는 경향, 3) 지배적 피드백 루프의 인식에 있어서 수준변수와 변화율 변수간의 차이 등이 포함된다. 마지막으로 본 논문에서는 지배적 피드백 루프에 의한 인지적 편향이 의사결정과정의 시간지연과 정책 개입의 시기에 대하여 어떠한 시사점을 주는지에 관하여 논의하였다.

• Proceedings of the Korean System Dynamics Society
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• 2000.07a
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• pp.49-61
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• 2000

본 논문에서는 정책개입시기를 이해하고 논의하는데 있어서 시스템 다이내믹스 학자들의 연구가 어떠한 시사점을 줄 수 있는가에 관하여 논의한다. 정책 시스템을 피드백 루프를 중심으로 하여 양의 피드백 루프가 지배하는 시스템, 음의 피드백 루프가 지배하는 시스템, 음과 양의 피드백 루프가 지배하는 시스템을 구분한다. 그리고 각 시스템에 있어서 바람직한 정책 개입의 시기에 관하여 논의하고, 어떠한 인지적 편향과 제도적 장애가 있는지를 논의한다.

• Journal of IKEEE
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• v.18 no.2
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• pp.220-227
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• 2014

This paper presents a control method of Single-Inductor Dual-Output DC-DC Converter using Common mode feedback and differential feedback loops. To generate duty used for differential mode feedback loop, this paper propose relative sawtooth circuit using current divider circuit which makes ramp signal with variable dead-time. Two outputs of the Single-Inductor Dual-Output DC-DC Converter are specified for 2.8 V and 4.2 V with input voltage 2.5 V. The maximum conversion efficiency of designed SIDO DC-DC Converter is 95% at total output power of 539mW. Cross regulations of Boost1 and Boost2 are 3.57% and 4% each, when increasing twice times output current.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.213-221
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• 2018

South Korea has been reluctant to open its geospatial information overseas to ensure security as a divided country. However, this cannot continue as the domestic and international environments related to geospatial information and the industrial ecosystem of information and communication technologies have been changing dramatically. Within this context, this study aims to analyze the causal relations among relevant variables and how they change and interact with time using a systems thinking process. First, causal maps were created for the domains of national security, map-based convergence service, and corporate competition. Then, the causal maps for each domain were integrated, based on which the points for policy intervention and dominant feedback loops were identified. The analysis results showed that securing the self-sufficiency of domestic geospatial businesses is a key element to determine the whole causal map, and the variable that changes the dominant feedback loop from a vicious circle to a virtuous one is the decision to open geospatial information overseas. In this study, I found the policy leverage that is a policy intervention point that can produce a great effect with little input by building a causal map of the interactions between major variables. This study is significant in that it identified and analyzed the dominant feedback loop as to which causal structure would dominate the system in the long term. The results of this study can be used to discuss not only the impacts of map data overseas opening on the national security and geospatial information industry, but also the interactions in the future when Google or other global companies request to release the geospatial information.

• Journal of IKEEE
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• v.21 no.2
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• pp.154-157
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• 2017

This paper proposes the Low-Dropout regulator with two output. Each of the two output has feedback, and shared feedback loop. PMOS is added to solve the problem the occur when sharing the feedback loop. Thus eased the Load Transient Response. Also Using one of the bias citcuit and one of the pass transistor, Area is reduce by half compared to Existing Area that used to obtain output of two output.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.15-23
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• 2000

If a system such as a port and regional economy has a large boundary and complexity, the system's substance is considered as a black box, forecast accuracy will be very low. Futhermore various components in a port and regional economy exert significant influence on each other. To copy with these problem the form of structure models were introduced by using SD model. This study has the issue of simplifying the regional economic effects of the port as contributing to raising the regional income. The regional economic effects of port have various indirect ones except for this. So, SD(System Dynamics) was presented, and applied to simulate port and regional economy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.514-520
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• 2004

In WDM networt a WDM buffer is one of essential elements for realizing all-optical packet switching system. In this paper, we propose and demonstrate a single loop type all-optical WDM buffer system. The proposed one consists of NOLM and feedback loop, and provides more than 40 turns buffering (more than 20${\mu}\textrm{s}$) for single input pulse (1550nm, width: 20㎱) before selected by control signal pulse (1553nm, width: 30㎱).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.324-332
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• 2016

In this paper, the terminal homing loop with a IIR-type strapdown seeker and a roll rate gyroscope is proposed. Basically, the proposed homing loop is based on the look-angle-control guidance. Since the range of the seeker is strictly limited, the missile is delivered to a point to lock the target on the seeker via non-guided flight during the midcourse guidance. The non-standard firing table is developed to compensate the wind and the target movement. To secure the delay margin is very important to prevent the instability of the homing loop when the time delay of the seeker is included. To validate the proposed homing loop, the 6-DOF nonlinear simulation is performed, and the Monte-Carlo simulation is also done for checking the robustness for the various kinds of uncertainty.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.6
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• pp.393-400
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• 2022

The Divert and Attitude Control System(DACS) used in high-altitude engagements is expensive and complex. In this paper, we design a high-altitude terminal guidance and control loop of guided-missile equipped with a Thrust Vector Control(TVC) that is less expensive and simpler than DACS. The proposed system utilizes a quaternion feedback control technique to track the thrust attitude command converted from the acceleration command of true proportional navigation guidance. The performance analysis of the proposed terminal guidance and control loop is conducted through engagement simulations against ballistic targets at a high altitude.