• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.594-600
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• 2007

A sufficient condition for the robust D-stability of dynamic interval systems is proposed in this paper. This D-stability condition is based on a parameter-dependent Lyapunov function obtained from the feasibility of a set of matrix inequalities defined at a series of partial-vertex-based interval matrices other than the total vertex matrices as previous results. This condition is also extended to the robust D-stabilization problem of dynamic interval systems, which supplies an effective synthesis procedure for any LMI D-region. The proposed conditions can be simplified to a set of LMIs, which can be solved by efficient interior point methods in polynomial time.

• 한국정보통신학회논문지
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• 제14권11호
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• pp.2478-2484
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• 2010

본 논문은 실시간 파노라마를 위한 영상의 특징점 검출 방법을 제안한다. 파노라마 연구는 최근 실시간 지역탐색이나 DVR 등에 적용하는 연구가 최근 활발히 진행되고 있다. 특히 특징점 검출은 파노라마를 이루는 가장 중요한 요소이다. 특징점 검출을 위해서는 어떠한 명암 변화에도 특징점은 불변이어야 하며 이미지의 크기와 회전이 변화하더라도 불변의 점을 찾아야 한다. 기존 연구방법은 고차원적인 벡터와 많은 후보점을 선점하기 때문에 연산량이 많고 수행시간이 길어 실시간에 활용하기에는 어려운 점이 있다. 따라서 본 논문은 보다 빠른 실시간 특징점 검출을 위해 LOG 방법을 비트 단위로 분할 후 결합하는 BLOG 방법을 제안하고 다양한 실험을 통하여 속도와 연산량 그리고 검출 성능에 대하여 비교한다.

• International journal of advanced smart convergence
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• 제5권4호
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• pp.1-9
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• 2016

In order to reconstruct a 3D model in video sequences, to select key frames that are easy to estimate a geometric model is essential. This paper proposes a method to easily extract informative frames from a handheld video. The method combines selection criteria based on appropriate-baseline determination between frames, frame jumping for fast searching in the video, geometric robust information criterion (GRIC) scores for the frame-to-frame homography and fundamental matrix, and blurry-frame removal. Through experiments with videos taken in indoor space, the proposed method shows creating a more robust 3D point cloud than existing methods, even in the presence of motion blur and degenerate motions.

• 정보처리학회논문지B
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• 제11B권7호
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• pp.813-820
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• 2004

본 논문에서는 할선법에 기초한 고정점 알고리즘의 ICA를 이용하여 기하학적 변형에 강건한 디지털 영상의 워터마킹을 제안하였다. 석기서 할선법의 고정점 알고리즘은 빠르면서도 개선된 추출성능을 얻기 위함이고, ICA의 이용은 검출 및 추출 과정에서 워터마크의 위치나 크기 등과 원본 및 키 영상에 대한 사전 지식의 요구를 없애기 위함이다. 제안된 기법을 $256{\times}25$ 픽셀의 원 영상(레나), 키 영상, 그리고 문자 워터마크 및 가우스잡음 워터마크에 각각 적용한 결과, 뉴우턴법의 고정점 알고리즘 ICA 워터마킹보다 빠른 추출시간과 개선된 추출성능이 있음을 확인하였다. 또한 제안된 할선법의 고정점 알고리즘 ICA에 의한 워터마킹은 크기와 회전 및 자름과 같은 기하학적 변형에 견고한 성능이 있음을 확인하였다. 특히 영상들 상호 간에 상관성이 적은 가우스잡음 워터마크가 문자 워터마크에 비해 우수한 추출성능이 있음도 확인하였다. 한편 워터마크의 검출 및 추출과정에 원본 영상들에 대한 사전지식도 요구되지 않았다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.322-326
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• 2003

In this paper, we establish a new robust $H_{\infty}$ performance condition for uncertain discrete-time systems with convex polytopic uncertainties. We express the condition as a set of linear matrix inequalities (LMIs), which are used to check stability and $H_{\infty}$ disturbance attenuation level by a parameter-dependent Lyapunov matrix. We show that the new condition provides less conservative result than the existing ones which use single Lyapunov matrix. We also show that the robust $H_{\infty}$ state feedback design problem for such uncertain discrete-time systems can be easily dealt with using the approach. The key point in this paper is to propose a kind of decoupling between the Lyapunov matrix and the system matrices in the parameter-dependent matrix inequality by introducing one new matrix variable.

• 한국컴퓨터정보학회논문지
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• 제23권1호
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• pp.41-48
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• 2018

Recently, surveillance systems are widely used, and one of the key technologies in this surveillance system is to recognize and track objects. In order to track a moving object robustly and efficiently in a complex environment, it is necessary to extract the feature points in the interesting object and to track the object using the feature points. In this paper, we propose a method to track interesting objects in real time by eliminating unnecessary information from objects, generating feature point descriptors using only key feature points, and reducing computational complexity for object recognition. Experimental results show that the proposed method is faster and more robust than conventional methods, and can accurately track objects in various environments.

• 한국컴퓨터정보학회논문지
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• 제22권8호
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• pp.63-72
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• 2017

In this paper, we propose a security architecture for HDLC-based T4 class common data link. The common data links are composed of point-to-point, multi-to-point, and point-to-multi mode. For multi-to-point mode, one node has a bundle of point-to-point links with different end-point on the other side of the links. Thus multi-to-point mode can be considered as a bundle of point-to-point mode. Point-to-multi mode is broadcasting link. For point-to-point mode we adopted robust security network scheme to establish a secure data link, and for multi-to-point mode we use broadcast encryption scheme based on ID-based cryptography to distribute encryption key for broadcasting message encryption. We also included MACsec technology for point-to-point data link security. Computational and communicational complexity analysis on the broadcast encryption have been done.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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• pp.89-92
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• 2012

Wireless Mesh Network expanded the capability of the conventional wireless networking by allowing the nodes to operate in proactive mode, reactive mode or the combination of both, the hybrid mode in the multi-hopping nature. By doing so, the links between the nodes become much more robust and reliable because of the number of paths to reach a destination node from a source node can be more than 1 and do not need to rely on the access point (AP) alone to relay the messages. As there may be many possible ways to form an end-to-end link between 2 nodes, the routing security becomes another main concern of the 802.11s protocol. Besides its reliance on the 802.11i for the security measures, 802.11s also includes some new features such as the Mesh Temporal Key (MTK) and the Simultaneous Authentication of Equals (SAE). The authentication and key management (AKM) process of 802.11s were observed in this paper.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.91-99
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• 2006

The diesel Auxiliary Power Unit (APU) for vehicle applications is a complex nonlinear system. For the purpose of this paper presents a dynamic average model of the whole system in an entirely physical way, which accounts for the non-ideal behavior of the diode rectifier, the nonlinear phenomena of generator-rectifier set in an elegant way, and also the dynamics of the dc load and diesel engine. Simulation results show the accuracy of the model. Based on the average model, a simple PI control scheme is proposed for the multivariable system, which includes the steps of model linearization, separate PI controller design with robust tuning rules, stability verification of the overall system by considering it as an uncertain one. Finally it is tested on a detailed switching model and good performances are shown for both set-point following and disturbance rejection.

• 한국전자파학회논문지
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• 제20권9호
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• pp.954-960
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• 2009

본 논문에서는 위치 기반 서비스(Location Based Service: LBS)의 핵심 기술에 속하는 측위 기술 중 Wi-Fi을 이용한 실내 위치 추정 시스템(Indoor Positioning System)을 제안한다. 제안하는 측위 시스템은 수신 받은 신호의 세기(Received Signal Strength Indicator: RSSI)를 경로 손실 모델(Path-Loss Model)을 이용하여 단말기와 AP(Access Point) 간의 거리를 추정한다. RSSI는 실내 환경 구조나 장애물 등으로 인해 발생하는 이상 잡음(outlier)의 영향을 받는다. 이러한 이상 잡음을 제거하기 위해 본 논문에서는 이상 잡음에 강인한 확장 칼만 필터를 이용한 측위 시스템을 제안한다. 본 논문에서 제안하는 측위 시스템의 성능을 확인하기 위해 단말기로 PDA를 이용하였으며, 실내 측위 시스템을 구현한 결과를 통해 원활한 실내 측위가 가능하다는 것을 확인하였다.