• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.426-429
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• 2003

건설공사는 프로젝트의 진행 중 내${\cdot}$외부의 여러 조건의 변경이나 사회적 요구에 따라 초기의 계약과는 다른 많은 변경사항이 발생하게 된다. 이러한 변경사항은 프로젝트 추진과정에서 많은 영향을 미치게 되며, 이로 인하여 발생되는 영향은 대부분 프로젝트의 공기지연으로 나타나게 된다. 건설공사에서 발생하는 공기 지연은 기본적으로 도급자의 면책여부에 따라 공기연장이나 지체상금의 부과 등의 결과로 나타나게 되는데 이러한 사항에 대한 발주자와 도급자의 의견이 대립될 경우 클레임으로 발전하게 된다. 클레임에서 가장 중요한 사항은 공기지연일수의 산정으로서 이는 공기지연 클레임에서 가장 중요한 부분이라고 할 수 있다. 본 연구에서는 공기지연 클레임에서 가장 중요한 자료가 되는 공기지연일수 산정방법의 한 방법으로 계약 초기에 작성된 계획공정표(As-Planned Schedule)와 모든 지연이 포함된 준공공정표(As-Built Schedule including all delays) 그리고 발주자 지연이 제외된 준공공정표(As-Built schedule absent owner delays)를 비교함으로써 각 계약 구성원의 귀책으로 인한 광기 지연일수 산정방법을 제시하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.136-138
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• 2006

Recently, network systems are widely used in several areas, and some considerable attentions have been directed to the Networked Control System(NCS). In NCS, network-induced delays are inevitable, and they sometimes degrade the performance of networked control systems to be a source of potential instability. In this paper, We proposes a compensation method for networked control system subject to network-induced delays by using a simple method, which is based on a sort of predictive strategy. To evaluate its feasibility and effectiveness, a real-time NCS for a rotary inverted pendulum is implemented via an Ethernet. Based on the experimental results. we show that the proposed simple method can be a practical and feasible solution to NCS design.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제8권8호
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• pp.191-200
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• 2019

애드혹 네트워크에서는 하나의 기준노드를 선정하여 이를 중심으로 네트워크 내에 모든 노드들의 시간을 동기화하는 방법을 사용할 수 있다. 이러한 기준노드를 중심으로 하는 대표적인 시간동기화 알고리즘은 Flooding Time Synchronization Protocol (FTSP) 이다. 메시지를 주고 받는 과정에서 예측할 수 있는 지연과 예측할 수 없는 랜덤 지연이 발생하게 되는데, 이러한 지연은 정확한 동기화를 방해하기 때문에 제거해야 한다. 멀티홉 기반의 통신에서 메시지를 주고받는 과정에 지나는 홉 수에 따라 홉 지연이 발생하게 된다. 이러한 홉 지연은 노드 사이의 동기화 성능을 크게 떨어뜨리게 된다. 따라서 이러한 홉 지연을 줄이고 동기화 성능을 높이기 위한 방법이 필요하다. 기존 FTSP 방식에서 기준 노드가 ID를 기반으로 가장 ID 값이 작은 노드가 기준노드로 선정되기 때문에 기준노드의 위치가 어디냐에 따라서 홉 지연에 따른 성능 저하가 크게 발생할 수 있다. 본 논문에서는 홉 지연을 줄이기 위한 최적의 기준노드 재선정 알고리즘을 제안하고 OPNET 네트워크 시뮬레이터를 사용하여 기존 FTSP와의 성능을 비교한다. 추가적으로 토폴로지 변경에 따른 성능을 측정하여 제안된 방식이 토폴로지 변환에 강인한 성능을 갖고 있음을 확인할 수 있었다.

• The Journal of the Acoustical Society of Korea
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• 제18권2E호
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• pp.10-17
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• 1999

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about 100m underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the array of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. This new acoustic imaging method shows the multi-dimensional distribution of the normalized cost function, so as to indicate the trend of the minimizing direction toward the source location. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is 28m for a search area of radius 250m.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.69-75
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• 2000

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about 100m underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the array of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. This new acoustic imaging method shows the multi-dimensional distribution of the normalized cost function, so as to indicate the trend of the minimizing direction toward the source location. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is 28m for a search area of radius 250m.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.103-108
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• 1999

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about loom underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the array of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. This new acoustic imaging method shows the multi-dimensional distribution of the normalized cost function, so as to indicate the trend of the minimizing direction toward the source location. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is 28m for a search area of radius 250m.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.149-152
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• 1999

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about loom underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the way of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. For each method the sound localization is carried out in three dimensions underground. The minimum distance between the true and estimated origins of the source is 28 m for a search area of radius 250m.

• 전자공학회논문지SC
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• 제40권3호
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• pp.99-108
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• 2003

본 논문에서는 시변 시간지연을 가지는 특이시스템에 대한 보장비용 상태제환 제어기 설계방법을 제시한다. 보장비용 제어기가 존재할 충분조건과 보장비용 제어기 설계방법 및 보장비용 함수의 상한치를 구하는 최적화 문제를 선형행렬부등식, 특이치 분해(singular value decomposition), 슈어 여수(Schur complements) 정리, 변수 치환 등에 의하여 제시한다. 구한 충분조건은 선형행렬부등식의 형태로 되기 때문에 보장비용 제어기의 이득과 보장비용 함수의 상한치를 포함하는 충분조건의 모든 해를 동시에 구할 수 있다, 또한, 제안한 알고리듬을 이용하면 변수 불확실성과 시변 시간지연을 동시에 가지는 특이시스템에 대한 강인 보장비용 제어기 설계문제에도 쉽게 확장됨을 보인다. 마지막으로, 제안한 알고리듬의 타당성을 수치예제를 통하여 확인한다.

• 전기학회논문지
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• 제62권5호
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• pp.679-687
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• 2013

This paper proposes a new condition about delay-dependent robust $H_{\infty}$ control of uncertain linear systems with time-varying delay and randomly occurring disturbances. The norm bounded uncertainties are subjected to the system matrices. Based on Lyapunov stability theory, a sufficient condition for designing a controller gain such that the closed-loop systems are asymptotically stable with $H_{\infty}$ disturbance level ${\gamma}$ is formulated in terms of linear matrix inequalities (LMIs). Finally, two numerical examples are included to show the effectiveness of the presented method.

• Journal of electromagnetic engineering and science
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• 제19권1호
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• pp.56-63
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• 2019

Typical negative group delay circuits (NGDC) are analyzed in terms of signal attenuation, group delay, and bandwidth using S-parameters. By inverting these formulations, we derive and present the design equations (for NGD circuit elements) for a desired specification of the two among the three parameters. The proposed design method is validated through simulation examples for narrow- and wide-band pulse inputs in the time and frequency domains. Moreover, an NGDC composed of lumped elements is fabricated at 1 GHz for measurement. As a function of frequency, the circuit-/EM-simulated and measured group delays are in good agreement. The provided simple NGDC design equations may be useful for many applications that require compensations of some signal delays.