• 한국시스템다이내믹스연구
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• 제13권1호
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• pp.113-131
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• 2012

Applying social network analysis techniques, this study examines complex system characteristics of industry-university joint research R&D networks. In specific, it focuses on whether these R&D networks comply with the power law, whose system typically presents the-rich-get-richer and the-poor-get-poor patterns. The basic data come from 7,751 industry-university joint research projects, all of which were carried out by Daejeon, Chungbuk, and Chungnam-based universities from January 2005 to October 2008. The empirical results reveal that the R&D networks abide by the power law. That is, a handful of business units and universities command an overwhelming majority in the joint links, indicating positive feedback dominance within the system.

• Journal of Power Electronics
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• 제15권5호
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• pp.1256-1263
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• 2015

A novel vector control strategy for a permanent magnet synchronous motor (PMSM) based on the kinetic energy stored in the rotor is proposed in this paper. The novel strategy is composed of two closed loops, in which the current loop is the inner loop, and the kinetic energy serves as the outer loop. The theoretical basis and the design procedure of the two loops are given. The feasibility of the proposed control strategy is verified by experimental results. When compared with traditional vector control strategies, the proposed vector control strategy based on energy feedback has better dynamic performance. In addition, an effective estimation solution for the load variation is put forward.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권7호
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• pp.137-147
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• 2018

우리나라는 OECD 회원국 가운데에서도 정부규제의 수준이 가장 높은 나라들 중의 하나로 인식되고 있다. 정부규제가 강할수록 민간부문의 경제 및 각종 사회활동들이 위축되고 이러한 현상은 국가 경쟁력을 약화시키는 요인으로 인식되고 있다. 정부규제는 여러 가지 형태로 수행될 수 있는 바, 이러한 정부규제는 정부경쟁력에 영향을 미치고 정부경쟁력은 국가경쟁력에 영향을 미칠 수 있다. 본 연구에서는 정부규제와 국가경쟁력 간에 작용하는 많은 요소들을 인과관계론적으로 검토하고, 이를 시스템사고 관점에서 인과지도를 작성한다. 이를 통하여 정부규제와 국가경쟁력 간에 작용하는 피이드 백 루프를 탐색하고 향후 정부규제와 국가경쟁력이 균형을 이루면서 선 순환적으로 강화될 수 있는 정책적 제안을 하는데 연구의 목적이 있다. 연구결과 강화루프 (Reinforcing Loop) 2개와 균형루프(Balancing Loop) 4개가 각각 발견되었다. 이러한 루프들은 규제와 국가경쟁력간의 관계에서 실질적으로 중요한 역할을 하는 관계라는 점이며, 정책결정자 입장에서는 이러한 루프들을 잘 활용하여 양자간의 관계를 균형있게 발전시킬 수 있도록 노력할 필요가 있다는 점을 시사해 준다.

• International Journal of Control, Automation, and Systems
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• 제3권1호
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• pp.56-69
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• 2005

In this paper, it is clearly shown that the two well-known necessary and sufficient conditions mp n as generic static output feedback pole-assignment and mp + d(m+p) n+d as generic minimum d-th order dynamic output feedback pole-assignment on complex field, unbelievably, do not match up each other in strictly proper linear systems. For the analysis, a diagram analysis is newly created (which is defined by the analysis of 'convoluted rectangular/dot diagrams' constructed via node-branch conversion of the signal flow graphs of output feedback gain loops). Under this diagram analysis, it is proved that the minimum d-th order dynamic output feedback compensator for pole-assignment in m-input, p-output, n-th order systems is quantitatively decomposed into static output feedback compensator and its associated d number of arbitrary 1st order dynamic elements in augmented (m+d)-input, (p+d)-output, (n+d)-th order systems. Total configuration of the mismatched data is presented in a Table.

• 한국시스템다이내믹스연구
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• 제8권2호
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• pp.275-294
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• 2007

The Roh administration, participatory government, has pursued deconcentration policies for promoting the balanced national development since 2002. The main policy instrument of the deconcentration policy is that the transferring of public institutions from capital region to local areas. However, it has been argued that these policies have resulted in another problems of policy side-effects, for instance, decreasing the national competitiveness. This paper aims to explore the problems of side-effects of deconcentration policies based on the Systems Thinking approach. On the Systems Thinking approach basis, this paper analysed the policy side-effects placed the focus on intended feedback loops and unintended feedback loops of the deconcentration policies.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2004년도 춘계학술대회
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• pp.316-335
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• 2004

This paper builds a system dynamics model analyzing first mover effect and growth strategy of online retailer, a major segment of B2C e-commerce. The dynamic model in this paper is calibrated to the online book market and Yes24.com as major test cases. The model consists of eight key value chain sectors. Five of these(Users, Site Operations, Human Resources, Financial Accounting, and Fundraising) are internal to the company, and three others(Market, Financial Market, and Relative Performance) are external to the company. With the model, this paper suggests research propositions representing positive feedback loops and negative feedback loops that lead to corporate growth and limits to growth according to dynamic causal relationships among eight key value chain sectors, and simulate these propositions.

• 전자공학회논문지B
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• 제33B권3호
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• pp.47-55
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• 1996

An optical transmitter, which is a key component of the optical transmission system, converts the electrical signal to optical signal and consists of a high-speed current-pulse driver for laser diode and low-speed feedback loops that stabilize optical power against aging, power supply voltage fluctuations, and ambient temperature changes. In this paper, the power-stabilizing part, which forms the bulk of the optical transmitter circuitry was designed in integrted circuits. Operational amplifiers and reference voltage generation circuits, which were identified as key building blocks for the power-stabilizing feedback loops, were designed and were subsequently verified through HSPICE simulations. The designed operational amplifier consists of a two-stage folded cascode amplifier and class AB output stage, whereas the reference voltage is obtained by bandgap reference circuits. Finally the power-stabilizing circuitry was laid out based on 3\mu$m CMOS design rules for fabrication.

• 한국통신학회논문지
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• 제25권10B호
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• pp.1722-1731
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• 2000

본 논문에서는 TDM 및 TDM/WDM 혼합형 광 ATM 스위치 구조에서 핵심 기능모듈인 광 셀 압축기와 역압축기를 새로이 제안하였다. 제안된 구조는 압축 및 역압축시 SOA 게이트와 광 궤환루프를 적용함으로써 구현을 위한 하드웨어를 줄였으며, 소수의 단을 직렬연결시 대용량의 광 펄스열을 압축 및 역압축할 수 있다. 제안된 광셀 압축기 구조를 이용한 4비트 단위 광 펄스 압축실험을 통해 시스템 적용을 구체화하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.105-108
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• 1989

This paper proposes a performance improvement to a control system with state feedback control loops and feedforward control loops proposed in a previous paper. The technique allows to solve the regulator problem and at the same time to make the system follow command signal. The scheme is implemented in a 16 bit microcomputer using a floating coprocessor. Tests on a DC machine have been conducted, comparisons with the previous results are made.

• 한국시스템다이내믹스연구
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• 제14권3호
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• pp.135-163
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• 2013

This study aims to analyze the feedback loops and policy simulation of price fluctuation of Korean Cattle. The Korean Cattle market shows the 'Cycle of Beef' since 1970. In general, the market for agricultural commodities exhibit repeated cycles of prices and production. Why Beef products market in Korea shows the fluctuation of cattle and beef price repeatedly for forty years? To find an answer, this paper explores the feedback structure of the dynamics of the beef market by the systems thinking and build a stock-flow diagram model for the simulation of future behavior of the market sector of the Cattle. The dynamic simulation model was developed to identify and analyze the cyclical behavior among many variables, which is the number of cattle (calves, cow, etc.), the price of cattle, the demand for beef, the desirable number of cattle, slaughter, etc. The results of this study demonstrate that dominant feedback loops between the number of cattle and livestock prices. The demand for Beef and slaughter with time delay, also the results of the simulation to explain the persistence of future price fluctuations and actions meat market until 2025.