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Constructing Nonlinear Sliding Surface for Spacecraft Attitude Control Problems

  • Cheon, Yee-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 1999.10a
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    • pp.41-44
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    • 1999
  • Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters(MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

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COMPARISON OF TOPOLOGIES ON THE FAMILY OF ALL TOPOLOGIES ON X

  • Kim, Jae-Ryong
    • Journal of the Chungcheong Mathematical Society
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    • v.31 no.4
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    • pp.387-396
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    • 2018
  • Topology may described a pattern of existence of elements of a given set X. The family ${\tau}(X)$ of all topologies given on a set X form a complete lattice. We will give some topologies on this lattice ${\tau}(X)$ using a fixed topology on X and we will regard ${\tau}(X)$ a topological space. Our purpose of this study is to comparison new topologies on the family ${\tau}(X)$ of all topologies induced old one.

EXISTENCE OF SOLUTIONS FOR GRADIENT TYPE ELLIPTIC SYSTEMS WITH LINKING METHODS

  • Jin, Yinghua;Choi, Q-Heung
    • Journal of the Chungcheong Mathematical Society
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    • v.20 no.1
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    • pp.65-70
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    • 2007
  • We study the existence of nontrivial solutions of the Gradient type Dirichlet boundary value problem for elliptic systems of the form $-{\Delta}U(x)={\nabla}F(x,U(x)),x{\in}{\Omega}$, where ${\Omega}{\subset}R^N(N{\geq}1)$ is a bounded regular domain and U = (u, v) : ${\Omega}{\rightarrow}R^2$. To study the system we use the liking theorem on product space.

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A New Perspective on style and its change in the historical Met-hodology on Dress. (복식사 연구 방법에 있어서 양식 및 그 변화에 관한 연구)

  • 최윤미;김민자
    • Journal of the Korean Society of Costume
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    • v.20
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    • pp.63-72
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    • 1993
  • The concept of style provides a useful structure in history of Art. In aspect of formative art, dress and art work are alike, so style is a useful concept in the historical methodology on dress. The main purpose of this study was to apply the art criticism to the historical methodology on dress. For this purpose, documentary studies about style as a tool of historical research were proceeded. The results were as follows : 1. The concept of style consists of the external form and the internal meaning as double roots. Therefore, it's indispensable that the two asp-ects of style, form and meaning, must to be harmonized to describe the historical phenomena in dress. 2. The change pattern of style in dress is not always predeterminate and regular according to the cyclical theory. From the alternative point of view, the change pattern of style could be to describe the continuous theory proposed by kroeber, Brodsky. The whole change of style is considered "liked solution" by this theory.is theory.

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Efficient Seismic Analysis of Bridge by Single Mode Spectrum Analysis Method (단일모드 스펙트럼해석법에 의한 교량의 효율적 내진해석)

  • 박윤봉;국무성;유승운;김선훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.487-494
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    • 2003
  • Recently it is used seismic analysis like single mode spectrum analysis, multi mode spectrum analysis and time history analysis in Korea. Because bridges are not special form of them but regular and simple form of them in our country, we must develope seismic analysis program of bridge based on single nude spectrum analysis. The program developed by this study reduces a Quantity and a time of calculation compared to SAP90 and gives accurate answers without errors. In the case of commercial program if we look for seismic load(P/sub e/(x)), we must increase the number of node and the larger the number of node the more a quantity and a time of calculation. But this program is exactly solved with basic node compared to commercial program.

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The effect of architectural form on the earthquake behavior of symmetric RC frame systems

  • Inan, Tugba;Korkmaz, Koray;Cagatay, Ismail H.
    • Computers and Concrete
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    • v.13 no.2
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    • pp.271-290
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    • 2014
  • In this study, structural irregularities in plan, which has a considerable effect on earthquake behavior of buildings, have been investigated in detail based on Turkish Earthquake Code 2007. The study consists of six main parametric models and a total of 144 sub-models that are grouped based on RC structural systems such as frame, frame + rigid core, frame with shear wall, and frame with shear wall + rigid core. All models are designed to have both symmetrical plan geometry and regular rigidity distribution. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, number of axes and the configuration of structural elements. Many findings are obtained and assessed as a result of the analysis for each structural irregularity. The study shows that structural irregularities can be observed in completely symmetric buildings in terms of plan geometry and rigidity distribution.

A Study on Overabundant Qi And Retaliating Qi Of Five Circuits And Six Qi (운기(運氣)의 승복(勝復)에 관한 연구(硏究))

  • Yun, Chang-yeol
    • Journal of Korean Medical classics
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    • v.31 no.1
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    • pp.79-93
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    • 2018
  • Objectives : The climate changes in the natural realm displays pheonomena of excess and deficiency due to the principle of Yiyinyiyangzhiweidao. Here, overabundant qi arises due to the works of multiplication and insultation. When this overabundant qi is in force, the retaliating qi appears without fail to create a parallel. This is the Autonomous Equilibrium Mechanism found in the natural world. Studying this mechanism is deeply significant in understanding the mechanisms of diseases. Methods : The paper is written by reviewing the texts found in Huangdineijing's Chapters of Yunqi, which are $Q{\grave{i}}jiaobiandalun$, Wuchangzhengdalun, $Liuyuanzhengj{\grave{i}}dalun$, Zhizhenyaodalun, and Suwenliuqixuanzhumiyu. Results & Conclusions : The overabundance and retaliation in Five Circuits take the form of the restrained child of the Five Circuits takes revenge on the overabundant qi on behalf of his mother. The overabundance and retaliation in Six Qi take the form of rapid healing of Benqi which was in stagnation. Traditionally, overabundant qi is the only one in existence when the Five Circuits are in excess and the year of Hai yin wu wei you xu's regular transformation. During this time, retaliating qi does not exist. When Five Circuits are in deficiency and in the year of Si shen zi chou mao chen's pattern transformation, both the overabundant and deficiency qis exist. However, regardless of regular transformation or pattern transformation, overabundant qi and retaliating qi cannot exist at the same time. This seems to be the rational conclusion. There are some regulations that overabundance and retaliation follow. First, the strong and weak, and number of days coincide. Second, overabundance qi appear during the first half of the period when the qi of controling heaven is in place. During the later half of the period when the qi of terrestrial effect is in force, retaliation qi is the one that appears. Third, overabundance and retaliation does not end with one time. Rather, they will continue to repeat appearance and disappearance without any set pattern. Fourth, the overabundance and retaliation of the guest qi and dominant qi only has overabundance and no retaliation.

Anomalous Event Detection in Traffic Video Based on Sequential Temporal Patterns of Spatial Interval Events

  • Ashok Kumar, P.M.;Vaidehi, V.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.1
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    • pp.169-189
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    • 2015
  • Detection of anomalous events from video streams is a challenging problem in many video surveillance applications. One such application that has received significant attention from the computer vision community is traffic video surveillance. In this paper, a Lossy Count based Sequential Temporal Pattern mining approach (LC-STP) is proposed for detecting spatio-temporal abnormal events (such as a traffic violation at junction) from sequences of video streams. The proposed approach relies mainly on spatial abstractions of each object, mining frequent temporal patterns in a sequence of video frames to form a regular temporal pattern. In order to detect each object in every frame, the input video is first pre-processed by applying Gaussian Mixture Models. After the detection of foreground objects, the tracking is carried out using block motion estimation by the three-step search method. The primitive events of the object are represented by assigning spatial and temporal symbols corresponding to their location and time information. These primitive events are analyzed to form a temporal pattern in a sequence of video frames, representing temporal relation between various object's primitive events. This is repeated for each window of sequences, and the support for temporal sequence is obtained based on LC-STP to discover regular patterns of normal events. Events deviating from these patterns are identified as anomalies. Unlike the traditional frequent item set mining methods, the proposed method generates maximal frequent patterns without candidate generation. Furthermore, experimental results show that the proposed method performs well and can detect video anomalies in real traffic video data.

Applying Image Processing Algorithm to Raw LiDAR Data for Extracting Ground Information (LiDAR 원시자료에서의 지면정보 추출을 위한 영상처리기법 적용 연구)

  • Choi, Yun-Woong;Sohn, Duk-Jae;Cho, Gi-Sung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.5
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    • pp.575-583
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    • 2009
  • Various algorithms and methods, related to preprocessing of LiDAR data, are being developed and proposed. These methods are two ways, one of them is to use the regular form such as DSM or the image converted from raw LiDAR data, and the other is to use raw LiDAR data directly. The image processing method is one of representative method for the regular grid form data. This method is easy to apply to a numerical analysis technique and has an advantage of modeling and noise elimination through smoothing, but it lose the information during the data conversion. This study apply the image processing method to the irregular raw LiDAR data directly for the extracting ground information with minimized information loss and evaluate the extracting accuracy of ground information.

Theoretical Prediction of Vertical Motion of Planing Monohull in Regular Head Waves - Improvement of Zarnick's Nonlinear Strip Method (선수 규칙파 중 단동 활주선의 연직면 거동 추정 - Zarnick 비선형 스트립 방법의 개선)

  • Zhang, Yang;Yum, Deuk-Joon;Kim, Dong-Jin
    • Journal of Ocean Engineering and Technology
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    • v.29 no.3
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    • pp.217-223
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    • 2015
  • In order to predict the motions of a planing hull in waves, it is necessary to accurately estimate the force components acting on the hull such as the hydrodynamic force, buoyancy, and friction, as well as the wave exciting force. In particular, based on strip theory, hydrodynamic forces can be estimated by the summation of the forces acting on each cross-section of the hull. A non-linear strip method for planing hulls was mathematically developed by Zarnick, and his formula has been used to predict the vertical motions of prismatic planing hulls in regular waves. In this study, several improvements were added to Zarnick's formula to predict the vertical motions of warped planing hulls. Based on calm water model test results, the buoyancy force and moment correction coefficients were modified. Further improvements were made in the pile-up correction. Pile-up correction factors were changed according to variations of the deadrise angles using the results found in previous research. Using the same hull form, captive model tests were carried out in other recent research, and the results were compared with the present calculation results. The comparison showed reasonably good agreements between the model tests and present calculations.