• 전기전자학회논문지
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• 제18권4호
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• pp.517-522
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• 2014

본 논문은 임의의 네트워크 시간 지연이 존재하는 선형 다개체 시스템의 일치문제를 다룬다. 다개체 시스템의 상태일치를 위한 충분조건은 선형행렬방정식을 이용하여 제공된다. 또한, 제안한 충분조건아래에서 임의의 크기를 갖는 네트워크 지연이 존재하는 경우에도 일치에 도달할 수 있음을 증명한다. 마지막으로 제안한 결과의 유효성을 증명하기 위하여 수치 예제를 제공한다.

• 한국정보통신학회논문지
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• 제18권5호
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• pp.1080-1086
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• 2014

본 논문에서는 CSMA/CA기반의 분산 무선 네트워크에 컨센서스 알고리즘을 적용할 때 발생하는 트레이드오프 성능을 분석한다. 컨센서스 알고리즘 자체는 협력 이웃 노드가 많을수록 빠른 수렴 속도를 갖지만, 무선 네트워크상에서는 협력 이웃 노드가 많을수록 접속 충돌로 인하여 전송 지연이 증가한다. 따라서 두 성능 간에 트레이드오프가 존재하며, 이로 인하여 컨센서스 달성 시간을 최소화하는 최적의 협력 이웃 노드 수가 존재한다. 시뮬레이션을 통하여 컨센서스 참여 노드 수에 따라 최적 이웃 노드 수를 도출한 결과, 네트워크 규모가 작을 때에는 모든 노드가 다 같이 협력하는 것이 최적이지만 네트워크 규모가 어느 이상으로 커질 경우에는 이웃 노드 수를 일정 값으로 제한하는 것이 최적 운용 전략이 된다.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.222-226
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• 2010

In this paper we study the consensus problem of SISO (Single-Input Single-Output) linear multi-agent systems under a fixed weighted undirected network communication. The dynamics of each agent can be of any order, while it is constrained to be neutrally stable. Based on a simple root locus argument, we show that the problem at hand is always solvable if the gain and zeros of the dynamic compensator, of which dimension is the same as the number of plant poles on the imaginary axis, are chosen suitably, finally the result is successfully verified by an example.

• 대한수학회지
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• 제61권3호
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• pp.565-602
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• 2024

We study the collective behaviors of two second-order nonlinear consensus models with a bonding force, namely the Kuramoto model and the Cucker-Smale model with inter-particle bonding force. The proposed models contain feedback control terms which induce collision avoidance and emergent consensus dynamics in a suitable framework. Through the cooperative interplays between feedback controls, initial state configuration tends to an ordered configuration asymptotically under suitable frameworks which are formulated in terms of system parameters and initial configurations. For a two-particle system on the real line, we show that the relative state tends to the preassigned value asymptotically, and we also provide several numerical examples to analyze the possible nonlinear dynamics of the proposed models, and compare them with analytical results.

• 전기전자학회논문지
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• 제22권1호
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• pp.121-126
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• 2018

본 논문은 관측기 기반의 제어기를 이용한 비선형 다개체 시스템의 일치문제를 다룬다. 이를 위하여 기존의 저이득 제어기에 고이득 접근방법을 결합한다. 리아푸노프 방법을 이용하여 제안한 관측기 기반의 일치 제어기가 삼각구조 비선형 시스템의 일치를 보장해줌을 보인다.

• 전기전자학회논문지
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• 제20권4호
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• pp.378-384
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• 2016

본 논문은 통신 지연을 가지는 방향 네트워크로 연결된 고차 적분기시스템의 출력 피드백 일치문제를 다룬다. 이 문제를 해결하기 위하여 기존의 저이득 제어기에 설계변수를 추가한 새로운 동적 출력 피드백 제어기를 제안한다. 또한, 제안한 제어기의 존재성이 임의로 큰 통신지연이 존재하는 경우에도 항상 보장됨을 증명한다.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.439-444
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• 2012

In this study, we address the formation control problem of coupled unicycle-type mobile robots, each of which can interact with its neighboring robots by communicating their position outputs. Each communication link between two mobile robots is assumed to be established according to the given time-varying interconnection topology that switches within a finite set of connected fixed undirected networks and has a non-vanishing dwell time. Under this setup, we propose a distributed formation control algorithm by using the dynamics extension and feedback linearization methods, and by employing a consensus algorithm for linear multi-agent systems which provides arbitrary fast convergence rate to the agreement of the multi-agent system. Finally, the proposed result is demonstrated through a computer simulation.

• Parasites, Hosts and Diseases
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• 제61권2호
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• pp.103-126
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• 2023

In the l950s, under the legacy of traditional agriculture, Ascaris lumbricoides, spread epidemically in the war-bitten society of Korea. Consensus on the parasite control was drafted in the Parasite Disease Prevention Act, which passed a parliamentary agreement in 1966, and established safe disposal of feces and mass chemotherapy as control strategies. Biannual stool examinations and treating infected schoolchildren were basic scheme of the control activity through which revenue could be secured for organized business. In the 27 years following 1969, a maximum of 16 million stool examinations had been done every year. Cellophane thick smear enabled the task. The infection declined remarkably in the 1970s when industrialization and green revolution proceeded. A population study of A. lumbricoides in the late 1970s helped us better understand its epidemiology. The data also settled down the understandable protest of teachers against the repeated stool examinations. In the 9 years following 1987, the target population was gradually reduced when the egg positive rate was below 0.1%. An article in the Korean Law, stipulating obligatory stool examinations, was made optional. Although the long-term Korean effort of Ascaris control was a success, the effect of mass chemotherapy was not as succinct in terms of lowering reinfection. In the period of control, Korean agricultural technology changed, and the economy grew and supplied sanitary facilities by which the vicious cycle was disconnected. Reduction of morbidity was a benefit of mass chemotherapy, which is the only control method feasible in economically difficult countries. The most important hurdle of parasite control in the 1960s was poverty of general population and limited financial resources in Korea but the society formed a consensus on the priority of intestinal helminthiasis control during the ordeal period. The national consensus in the 1960s was the critical milestone for Ascaris control in Korea. Under the social agreement, application of timely technical and research advancements in parasitology achieved the success of ascariasis elimination. The successful experience of ascariasis elimination in Korea can be a benchmark for countries where neglected tropical diseases are endemically recycled.

• 한국항공우주학회지
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• 제36권10호
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• pp.988-995
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• 2008

본 논문에서는 궤환선형화를 이용한 일치기법을 사용하여 다수 무인기의 편대비행 제어기를 설계하였다. 제안한 기법은 한 대의 리더기를 중심으로 하는 집중형 방식이 아닌 분산형 방식으로, 각 개체의 제어입력은 인접한 개체만의 정보만을 이용하여 설계된다. 라플라시안 행렬을 이용하여 개체 간의 정보 교류를 정의한 후, 궤환선형화 과정을 거친 비행체에 적용하였다. 또한, 본 논문에서 제안한 제어기의 안정성 해석을 수행하였다. 또한 제안한 제어기의 성능을 검증하기 위해서 회전익 무인기 비행체 모델에 대한 수치 시뮬레이션을 수행하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권6호
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• pp.1042-1062
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• 2010

Cooperative spectrum sensing (CSS) is an effective technology for alleviating the unreliability of local spectrum sensing due to fading/shadowing effects. Unlike most existing solutions, this paper considers the use of CSS technology in decentralized networks where a fusion center is not available. In such a decentralized network, some attackers may sneak into the ranks of cooperative users. On the basis of recent advances in bio-inspired consensus algorithms, an attack-proof, decentralized CSS scheme is proposed in which all secondary users can maintain cooperative sensing by exchanging information locally instead of requiring centralized control or data fusion. Users no longer need any prior knowledge of the network. To counter three potential categories of spectrum sensing data falsification (SSDF) attacks, some anti-attack strategies are applied to the iterative process of information exchange. This enables most authentic users to exclude potentially malicious users from their neighborhood. As represented by simulation results, the proposed scheme can generally ensure that most authentic users reach a consensus within the given number of iterations, and it also demonstrates much better robustness against different SSDF attacks than several existing schemes.