• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.29-34
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• 1999

We present a practical method for removing biotches and restoring their mission data. To detect blotches, we employ a robust approach of local analysis of spatiotemporal anisotropic brightness continuity Our approach uses first-order spatiotemporal directional derivatives to select the smoothest direction for each examined pixel, and puts out the incorruption probability that he examined pixel may not be corrupted by blotches. As the restoration filter, were employ a spatiotemporal fuzzy filter whose response is adaptively controlled according to a fuzzy rule defined by the incorruption probability. The fuzzy filter is composed of the two different filter of the identity filter and the spatiotemporal directional-weighted-mean filter, and will put out an intermediate value between the original input brightness and the directional-weighted-mean brightness. We design the fuzzy rule in advance by a standard supervised learning fuzzy rule in advance by a standard supervised learning method. The computer simulations are presented.

• The Korean Journal of Ecology
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• 제13권2호
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• pp.83-92
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• 1990

Two-dimensional analysis provides a comprehensive description of the structure, scales of pattern and directional components in a spatial data set. In spectral analysisi, four functions are illustrated,; the autocorrelation, the periodogram, the R-spectrum and the $\theta$ -spectrum. The R-spectrum and $\theta$ -spectrum function respectively summarize the periodogram in term of scale of pattern and directional components. Sampling is measured in the Naejang National Park area where the Daphniphyllum trees grow. 320 contiguous (15$\times$15)m plots are located along the transect and density of all trees over DBH 3 cm recorded respectively. 12 species of vascular plant are recorded in this survey area. The trend surface of density of all plant are estimated using polynomial regression and are exhibited in 3-dimensional graph and density contour map. Transformation to the corresponding polar spectrum from the periodogram emphasized the directional components and the scales to pattern. R-spectrum corresponding to the scale of pattern of periodogram showed a large peak 15.47 in the interval 9$\theta$-spectrum corresponding to directional components have two peaks 8.28 and 11.05 in the interval $35^{\circ}\theta <45^{\circ}and 125^{\circ}\theta< <135^{\circ}, respectively. Programs to compute all the analyses described in this study was obtained from Dr. Ranshow and was translated to BASIC by the author.

• 자원ㆍ환경경제연구
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• 제16권1호
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• pp.171-197
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• 2007

본 논문에서는 자료 제약의 현실적 상황에서 Porter 가설이 성립되기 위한 조건을 제시한다. 이를 위하여 기업의 생산비용 최소화 달성 여부에 관계없이 성립함으로써 분석결과의 신뢰성을 확보할 수 있는 두 유형의 산출물거리함수를 활용한다. Shephard 거리함수와 방향 거리함수, Shephard 거리함수로부터 공해물질의 한계저감비용을 구한 다음, Porter 가설이 내포한 생산기술이 전제되어 있는 방향 거리함수를 추정하여 얻은 한계저감비용과 비교한다. 국내 전력산업을 대상으로 1970~1998년 기간 동안 방향 거리함수에 의한 $SO_2$의 연평균 한계저감비용은 Shephard 거리함수 도출값보다 약 50퍼센트 높게 나타났는데 이는 Porter 가설이 성립하기 위해서는 새로운 발전시설과 공정에 투자하여 생산성을 평균적으로 50퍼센트 이상 향상시킬 수 있어야 함을 의미한다.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.257-266
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• 2007

멀티미디어 응용분야에서 영상 압축부호화는 영상의 데이터량을 줄이기 위해 필수적이다. 그러나 이러한 압축부호화는 화질의 열화를 발생시킨다. 블록킹 현상과 모기 잡음은 이산여현변환 기반의 압축 영상에서 전형적인 열화이고, 에지 주변의 링잉 현상은 웨이블릿 기반의 압축영상에서 발생한다. 본 논문에서는 방향성을 고려한 후처리방법을 제안하고자 한다. 제안하는 방법은 복호된 화질의 개선을 위해 에지의 방향 검출과 보간법, 방향성 비선형 필터링을 포함한다 다양한 영상에 대해 시험한 결과, 제안된 방법이 다른 비선형 필터 방법에 비해 우수한 성능을 나타내었다.

• KIEAE Journal
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• 제9권2호
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• pp.81-90
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• 2009

Relating to grasping sequential landscape characteristics in consideration of the behavioral characteristics of the subject experiencing visual perception, this study was made on the subject of main walking line section for visitors of three treasures of Buddhist temples. Especially, as a method of obtaining data for grasping sequential visual perception landscape, the researcher employed [momentum sequential viewpoint setup] according to [the interval of pointers arbitrarily] and fisheye-lens-camera photography using the obtained omni-directional angle visual perception information. As a result, in terms of viewpoint selection, factors like approach road form, change in circulation axis, change in the ground surface level, appearance of objects, etc. were verified to make effect, and among these, approach road form and circulation axis change turned out to be the greatest influences. In addition, as a result of reviewing the effectiveness via the subjects, for the sake of qualitative evaluation of landscape components using the VR picture image obtained in the process of acquiring omni-directional angle visual perception information, a positive result over certain values was earned in terms of panoramic vision, scene reproduction, three-dimensional perspective, etc. This convinces us of the possibility to activate the qualitative evaluation of omni-directional angle picture information and the study of landscape through it henceforth.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권12호
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• pp.5820-5834
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• 2017

This paper investigates the channel selection problem with dynamic users and the asymmetric interference relation in distributed opportunistic spectrum access systems. Since users transmitting data are based on their traffic demands, they dynamically compete for the channel occupation. Moreover, the heterogeneous interference range leads to asymmetric interference relation. The dynamic users and asymmetric interference relation bring about new challenges such as dynamic random systems and poor fairness. In this article, we will focus on maximizing the tradeoff between the achievable utility and access cost of each user, formulate the channel selection problem as a directional graphical game and prove it as an exact potential game presenting at least one pure Nash equilibrium point. We show that the best NE point maximizes both the personal and system utility, and employ the stochastic learning approach algorithm for achieving the best NE point. Simulation results show that the algorithm converges, presents near-optimal performance and good fairness, and the directional graphical model improves the systems throughput performance in different asymmetric level systems.

• 소음진동
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• 제9권1호
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• pp.60-69
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• 1999

In the first paper of this research$^{(1)}$. a new time series method. directional ARMAX (dARMAX) model-based approach. was proposed for rotordynamics identification. The dARMAX processes complex-valued signals, utilizing the complex modal testing theory which enables the separation of the backward and forward modes in the two-sided frequency domain and makes effective modal parameter identification possible. to account for the dynamic characteristics inherent in rotating machinery. In this second part. an evaluation of its performance characteristics based on both simulated and experimental data is presented. Numerical simulations are carried out to show that the method. a complex time series method. successfully implements the complex modal testing in the time domain. and it is superior in nature to the conventional ARMAX and the frequency-domain methods in the estimation of the modal parameters for isotropic and weakly anisotropic rotor systems. Experiments are carried out to demonstrate the applicability and the effectiveness of the dARMAX model-based approach, following the proposed fitting strategy. for the rotordynamics identification.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.634-640
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• 2015

This paper proposes a novel three-dimensional mapping algorithm in Omni-Directional Vision SLAM based on a fisheye image and laser scanner data. The performance of SLAM has been improved by various estimation methods, sensors with multiple functions, or sensor fusion. Conventional 3D SLAM approaches which mainly employed RGB-D cameras to obtain depth information are not suitable for mobile robot applications because RGB-D camera system with multiple cameras have a greater size and slow processing time for the calculation of the depth information for omni-directional images. In this paper, we used a fisheye camera installed facing downwards and a two-dimensional laser scanner separate from the camera at a constant distance. We calculated fusion points from the plane coordinates of obstacles obtained by the information of the two-dimensional laser scanner and the outline of obstacles obtained by the omni-directional image sensor that can acquire surround view at the same time. The effectiveness of the proposed method is confirmed through comparison between maps obtained using the proposed algorithm and real maps.

• 한국측량학회지
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• 제34권3호
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• pp.329-338
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• 2016

최근 실내공간정보에 대한 수요가 증가함에 따라 다양한 활용 서비스가 개발되고 있다. 그동안 2차원 또는 3차원 실내공간정보 서비스에서, 최근에는 전방위 영상 기반의 실내공간정보 서비스가 증가하고 있다. 단순히 실내공간의 가시화만을 제공하는 기존 전방위 영상 기반 서비스가 속성 검색, 질의 가능 서비스 등을 제공하기 위해서는 공간간의 위치 관계가 정의된 토폴로지 데이터가 반드시 필요하다. 이에 따라 본 연구에서는 전방위 영상 기반의 다양한 실내공간정보 서비스를 위해 필요한 실내 토폴로지 데이터를 국제 표준인 IndoorGML 형식에 맞춰 생성하는 방법을 제안하도록 한다. 본 연구에서는 영상으로부터 IndoorGML 데이터 생성을 위해 1)IndoorGML 기본 개념의 영상 적용을 위한 고려사항 분석, 2)IndoorGML 데이터 생성을 위해 필수 정의 요소인 ‘공간’을 대표하는 객체 식별 방법 제시, 3)공간 사이의 연결성을 정의로 구분하여 IndoorGML 데이터 생성 방법을 제안한다. 제안한 방법은 서울시립대학교 21세기관 6층을 대상으로 적용되어 IndoorGML 데이터를 생성하도록 한다. 본 연구는 향후 IndoorGML을 기반으로 개발되는 다양한 실내공간정보 서비스에 토폴로지 데이터를 생성하는 한 가지 유형의 방법을 제시한다는 점에서 의의가 있다.

• 전자공학회논문지
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• 제50권7호
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• pp.292-299
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• 2013

본 논문에서는 IEEE 802.15.3 Medium Access Control Layer(MAC)와 UWB PHY(Physical Layer)의 기반에서 유/무선 통신이 가능한 동축 케이블 기반의 데이터 전송 시스템을 설계하고 구현하였다. 구현된 시스템은 가정용 동축 케이블(Coaxial Cable)이나 광동축 혼합망(Hybrid Fiber Coax) 기반에서 기가비트(Gigabit) 전송률로 양방향 데이터 전송이 가능하다. 본 동 축케이블 기반의 송수신 시스템은 가정이나 사무실의 $75{\Omega}$ 동축 케이블로 명령, 제어 그리고 데이터가 송수신 된다. 구현된 시스템은 중심 주파수 4GHz에서 1.33GHz의 대역폭으로 동작하며, BPSK를 사용하여 채널 전력의 ${\pm}15dBm$으로 심벌을 송신한다. 개발된 시스템을 일반적인 가정환경 내에서의 실험 조건으로 최대 3개의 CATV RF 분배기를 통해 동작함을 확인하였다.