• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.749-753
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• 2007

The purpose of this study is to design of a linear feeder using a multi body dynamic program, and to analyze a dynamic motion of the feeder that can transport small mechanical parts uniformly. In order to establish the analysis model of the linear feeder, each parts of the feeder are divided into two types which the rigid and flexible body. For the dynamic simulation, RecurDyn, which is a commercial multi-body dynamic package, is used. We also consider the design parameters for optimal dynamic motion such as centroid, stiffness, and mass of the feeder system. In order to analyze the dynamic motion of a linear feeder, the displacements of the feeder are measured by several accelerometers when it is in an operating condition. After the signal data from the accelerometers are captured in the time domain, the dynamic motion in the space is visualized by using graphic computer software.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1913-1917
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• 2000

SMD Equipment convey an electronic parts at high speed, then assemble parts into a circuit board, and it develop a long time-duration dynamic force to be caused by moving mass. Vibration problem to be caused by SMD Equipment have an effect on micro-meter level's precision production process, directly, and dynamic stability of building. In the cause of quantitatively access about its vibration problem, input information(or data) of structure dynamic analysis need accuracy information of dynamic load. Determination of Dynamic load is various kinds of method using experimental and theory. In this paper, we got dynamic load using direct measurement method. We expect that an study on the dynamic load characteristic of SMD can be used to Equipment development of low level vibration and basis information of structure dynamic analysis.

• 대한임베디드공학회논문지
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• 제19권1호
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• pp.65-71
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• 2024

An indirect visual SLAM takes raw image data and exploits geometric information such as key-points and line edges. Due to various environmental changes, SLAM performance may decrease. The main problem is caused by dynamic objects especially in highly crowded environments. In this paper, we propose a robust feature-based visual SLAM, building on ORB-SLAM, via multi-channel dynamic objects estimation. An optical flow and deep learning-based object detection algorithm each estimate different types of dynamic object information. Proposed method incorporates two dynamic object information and creates multi-channel dynamic masks. In this method, information on actually moving dynamic objects and potential dynamic objects can be obtained. Finally, dynamic objects included in the masks are removed in feature extraction part. As a results, proposed method can obtain more precise camera poses. The superiority of our ORB-SLAM was verified to compared with conventional ORB-SLAM by the experiment using KITTI odometry dataset.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.153-158
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• 1992

The purpose of this paper is to calculate the dynamic derivatives of single rotor Helicopter in forward flight. From trim condition, the equation of motion is derived, and we can calculate the dynamic dervatives. The results were compared with flight test data. The phase angle and stick displacement are obtained and compared at the trim condition.

• 한국기계연구소 소보
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• 통권18호
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• pp.147-152
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• 1988

The dynamic simulation for automobile running on bumpy road is introduced. The modeling method that is a very close approximation to automobile is presented. Because the output printed at every integration time step is lots of amount, to save the time of interpretation of dynamic response, the ouptput data are interactively processed by PLOT88, also a configuration of automobile is generated by animated graphic displays using PADL and APPLICON.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.151-159
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• 2014

Computed tomography (CT) is one of the most widely used medical imaging modality. However, substantial x-ray dose exposed to the human subject during the CT scan is a great concern. Region-of-interest (ROI) CT is considered to be a possible solution for its potential to reduce the x-ray dose to the human subject. In most of ROI-CT scans, the ROI is set to a circular shape whose diameter is often considerably smaller than the full field-of-view (FOV). However, an arbitrarily shaped ROI is very desirable to reduce the x-ray dose more than the circularly shaped ROI can do. We propose a new method to make a non-circular convex-shaped ROI along with the image reconstruction method. To make a ROI with an arbitrary convex shape, dynamic collimations are necessary to minimize the x-ray dose at each angle of view. In addition to the dynamic collimation, we get the ROI projection data with slightly lower sampling rate in the view direction to further reduce the x-ray dose. We reconstruct images from the ROI projection data in the compressed sensing (CS) framework assisted by the exterior projection data acquired from the pilot scan to set the ROI. To validate the proposed method, we used the experimental micro-CT projection data after truncating them to simulate the dynamic collimation. The reconstructed ROI images showed little errors as compared to the images reconstructed from the full-FOV scan data as well as little artifacts inside the ROI. We expect the proposed method can significantly reduce the x-ray dose in CT scans if the dynamic collimation is realized in real CT machines.

• 대한교통학회지
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• 제27권6호
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• pp.129-137
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• 2009

첨단교통체계의 기술발전과 교통 분석의 수준이 상세해짐에 따라 동적 교통 분석에 대한 필요성이 증가하고 있다. 기존의 정적인 분석이 하루 평균 개념의 통행특성과 네트워크 상태를 묘사한 반면, 동적 분석에서는 시간흐름에 따른 네트워크의 상태를 분석한다. 본 논문에서는 교통시스템 동적 분석의 필요성을 인식하여, 고속도로망을 대상으로 FTMS 자료를 활용한 분석 방법론을 개발하였다. 개별 차량의 실제 통행기록 자료인 TCS 자료를 이용하여 전국 고속도로망을 대상으로 동적 기종점 통행량을 구축하였으며, 시뮬레이션 연산시간 문제 해결을 위해 분석범위를 설정한 Subarea 분석을 활용하였다. 이를 위해 전국 고속도로망을 대상으로 구축된 시간대별 기종점 통행량을 Subarea 기종점 통행량으로 전환하기 위한 방법론을 개발하였다. 구축된 모형의 적용을 위해 시나리오 분석을 실시하였으며, 이를 통해 각각의 시나리오에 대하여 기존의 단편적인 효과분석과 달리 하루 중 시간대별 교통여건에 따른 네트워크 상태분석을 수행하였다. 본 연구는 동적 교통 분석의 초기 시도라는 점과 실제 기종점 자료인 FTMS 자료를 활용한 분석이라는 점에서 의미를 가지며, 현재 교통 분석의 큰 흐름인 동적 교통 분석의 필요성을 부각시키고자 한다. 향후 고속도로뿐만이 아닌 기타 도로를 포함한 모형 구축이 필요하며, Hybrid 모형 및 프로그램 개발을 통해 궁극적인 목표인 실시간동적 분석 모형 개발을 위한 연산시간 문제 해결이 필요할 것이다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.109-114
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• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• 설비공학논문집
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• 제20권12호
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• pp.781-788
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• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• 한국정보과학회논문지:정보통신
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• 제35권4호
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• pp.318-325
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• 2008

대부분의 센서네트워크 응용들은 일정기간 동안 센서데이타를 지속적으로 수집 분석한다. 이때 모든 센서가 계속해서 서버로 데이타를 전송하기 때문에 많은 통신비용이 소모된다. 따라서 통신비용 감소를 위한 기술은 배터리를 이용해 동작하는 무선 센서에 기반한 센서네트워크의 수명 연장을 위한 가장 핵심적인 기술이라 할 수 있다. 본 연구에서는 센서데이타를 압축 전송함으로써 통신비용을 감소시키기 위한 동적 비트할당 기법에 기반한 센서데이타 압축 기법을 제안한다. 제안하는 기법은 일정기간 동안 수집한 센서데이타의 분포를 분석해 센서데이타를 비트로 표현할 수 있는 정보를 각 센서에 배포하고, 데이타를 압축해 수집함으로써 통신비용을 효과적으로 줄일 수 있다.