• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.7
• /
• pp.370-377
• /
• 2000

This paper presents a decentralized compensator design procedure for large scale systems. By using a coordinate transformation method, interconnection terms in t도 subsystem are decoupled and a decentralized observer is designed independently as a form of Luenberger-type for each subsystem. And the decentralized compensator which can select the observer and controller gain independently is designed as a form of observer based controller for each subsystem. The proposed method has a simplicity and conciseness in the aspects of the determination of coordinate transformation matrices and the derivation of the separation principle which is adopted independently for each subsystem.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2015.07a
• /
• pp.326-327
• /
• 2015

본 논문에서는 화재의 움직임 정보에 기반하여 역동적인 화재를 감지하는 기법을 제안한다. 우선 감시 카메라와 같은 고정형 감시 장치로부터 얻어진 색 정보를 분리하기 쉬운 좌표계로 변환하고 이전에 수집된 데이터들로부터 얻어진 사전 정보로부터 화염 영역을 추출한다. 또한 화염 영역의 가장자리가 움직임이 매우 크다는 사실에 기반하여 광흐름 벡터로 얻어진 시간적 분산값을 이용한 움직임 모델을 생성한다. 화염 영역은 움직임 모델과 결합되며 오탐을 걸러내기 위해 충분한 양의 화재 영역이 중첩될 때 최종적으로 화재를 판별한다. 본 논문에서 제안한 방법은 실험 결과에서 우수한 탐지 능력을 보인다.

• 한국HCI학회:학술대회논문집
• /
• 2006.02a
• /
• pp.859-864
• /
• 2006

Mean shift 는 데이터의 특징을 잘 살려내는 None-parametric 방법으로, 특히 영상처리분야에서 많은 각광을 받아왔다. 하지만 좋은 결과를 보장하는 뛰어난 성능에도 불구하고, 높은 메모리소요와 긴 처리시간에 기인하여, 비디오처리 등의 분야에 적용하기엔 현실적인 제약점이 있다. 상기한 제약점을 극복하기 위해, 본 시스템은 비디오를 분석하여 전경과 후경으로 나눈다. 본 논문은 전경으로 분류된 부분에 대해 각 분리된 개체를구분하고, 좌표변환(coordinate shift)을 실행하여 연산을 할 비디오의 연산의 규모를 줄이는 방법론을 제시한다. 이러한 처리로 매우 많은 처리시간이 단축됨을 실험을 통해 알 수 있었다. 다음으로, 나뉘어진 전경에 3D mean shift를 적용하여 생성된 결과물에 대하여 3D cluster data structure 를 생성하고, 이를 이동하여 인터랙티브 에디팅이 가능하도록 하였다. 후경으로 나뉜 데이터는 이미지 한 장으로 축약이 되며, 2D mean shift 기반의 interactive cartooning system 을 통하여 만화화가 된다. 본 논문은 만화 특유의 단순한 톤을 표현하기 위해, 세밀한 분할이 필요한 부분과 그렇지 않은 부분을 따로 구분하여 처리하는 레이어처리방법을 제안한다. 위의 과정을 여러 실사이미지에 적용, 실험해본 결과 기존의 연구결과에 비해 매우 짧은 시간 내에 대상의 특징이 잘 나타낸 양질의 결과물이 생성되었다. 이러한 결과물은 출판, 영상편집분야 등 여러 분야에서 요긴하고 간편하게 사용될 수 있을 것으로 생각된다.

• The Journal of the Acoustical Society of Korea
• /
• v.14 no.1
• /
• pp.108-114
• /
• 1995

Cylindrical chamber mufflers with an extended inlet or outlet are extensively used in many application fields to reduce the propagated noise in ducts. The basic attenuation effectivencess in the low frequency region can be explained by the reactive wave action inside the expansion chamber associated with the geometric configurations of the inlet and outlet locations, and the area expansion of the jacket. In this study, an acoustic analysis is carried out for a concentric extended pipe inserted into a simple expansion chamber. An algebraic equation is derived by using the eigenfuction expansion and orthogonality principle in which the acoustic pressures and particle velocities defined on each subdivided surface are expressed by the separable coordinates. By using the proposed analytical method, transmission losses are predicted for several configurations of the concentric extended systems and they agree very well with experimental results.

• Journal of Korea Game Society
• /
• v.15 no.5
• /
• pp.99-108
• /
• 2015

To identify the location of the object and improve the realism in 3D game, shadow mapping is widely used to compute the depth values of vertices in view of the light position. Since the depth value of the shadow map is calculated by the world coordinate, the depth values of the static object don't need to be updated. In this paper, (1) in order to improve the rendering speed, using multiple render targets the depth values of static objects stored only once are separated from those of dynamic objects stored each time. And (2) in order to improve the shadow quality in the quarter view 3D game, the position of the light is located close to dynamic objects traveled along the camera each time. The effectiveness of the proposed method is verified by the experiments according to the different static and dynamics object configuration in 3D game.

• Journal of IKEEE
• /
• v.26 no.2
• /
• pp.265-270
• /
• 2022

This paper proposes the detection algorithm for switch open fault of asymmetric 6-phase PMSM based on stationary reference frame dq-axis currents. In this paper, target motor has an asymmetric structure in which two upper three windings have an electrical phase difference of 30° and a neutral point is separated. As a result, dual 3-phase PWM inverters and the detection techniques due to open failures of switch are definitely required. In this paper, the dual dq-axis current control method is used for driving the asymmetric 6-phase PMSM and the open fault switch should be detected by using variable all pass filter and low pass filter in order to detect the current amplitude. The effectiveness and usefulness of the proposed method is verified by several experiments.

• Journal of the Korean GEO-environmental Society
• /
• v.25 no.4
• /
• pp.21-28
• /
• 2024

In this study, a polyhedral domain decomposition method for Smoothed Particle Hydrodynamics (SPH) analysis is introduced. SPH which is one of meshless methods is a numerical analysis method for fluid flow simulation. It can be useful for analyzing fluidic soil or fluid-structure interaction problems. SPH is a particle-based method, where increased particle count generally improves accuracy but diminishes numerical efficiency. To enhance numerical efficiency, parallel processing algorithms are commonly employed with the Cartesian coordinate-based domain decomposition method. However, for parallel analysis of complex geometric shapes or fluidic problems under dynamic boundary conditions, the Cartesian coordinate-based domain decomposition method may not be suitable. The introduced polyhedral domain decomposition technique offers advantages in enhancing parallel efficiency in such problems. It allows partitioning into various forms of 3D polyhedral elements to better fit the problem. Physical properties of SPH particles are calculated using information from neighboring particles within the smoothing length. Methods for sharing particle information physically separable at partitioning and sharing information at cross-points where parallel efficiency might diminish are presented. Through numerical analysis examples, the proposed method's parallel efficiency approached 95% for up to 12 cores. However, as the number of cores is increased, parallel efficiency is decreased due to increased information sharing among cores.

• Journal of KIISE:Software and Applications
• /
• v.33 no.3
• /
• pp.335-343
• /
• 2006

This paper proposes a novel technique of marker-based 2D-3D registration to combine 3D information obtained from preoperative CT images into 2D image obtained from intraoperative x-ray fluoroscopy image. Our method is divided into preoperative and intraoperative procedures. In preoperative procedure, we generate CT-derived DRRs using graphics hardware and detect markers automatically. In intraoperative procedure, we propose a hierarchical two- step registration to reduce a degree of freedom from 6-DOP to 2-DOF which is composed of in-plane registration using principal axis method and out-plane registration using minimal error searching method in spherical coordinate. For experimentation, we use cardiac phantom datasets with confirmation markers and evaluate our method in the aspects of visual inspection, accuracy and processing time. As experimental results, our method keeps accuracy and aligns very fast by reducing real-time computations.

• The Journal of the Korea Contents Association
• /
• v.3 no.2
• /
• pp.24-30
• /
• 2003

Pre-existing authentication system such as token based method, knowledge-based and hybrid method have problems such as loss and wiretapping. for this, this paper describes the biometric authentication system which have the excellent convenience and security. In particular, a new biometric system by human face biometric features which have the non-enforcement and non-touch measurement is proposed. Firstly, facial features are extracted by Y- histogram and tilted face images we corrected by coordinate transformation and scaling has done for achieving independent of the camera positions. Secondly, feature vectors are extracted such as distance and intersection angles and similarities we measured by fuzzy relation matrix. finally, the effectiveness of this paper is demonstrated by experiments.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.210-214
• /
• 2008

It is actually impossible to model and store all objects which exist in real home environment into robot's database in advance. To resolve this problem, this paper proposes new object modeling method that can be available for robot self-modeling, which is capable of estimating whole model's shape from partial surface data using Generic Model. And this whole produce is conducted to cylindrical objects like cup, bottles and cans which can be easily found at indoor environment. The detailed process is firstly we obtain cylinder's initial principle axis using points coordinates and normal vectors from object's surface after we separate cylindrical object from 3D image. This 3D image is obtained from 3D sensor. And second, we compensate errors in the principle axis repeatedly. Then finally, we do modeling whole cylindrical object using cross sectional principal axis and its radius To show the feasibility of the algorithm, We implemented it and evaluated its accuracy.