• Journal of the Korea Computer Graphics Society
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• v.19 no.2
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• pp.1-8
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• 2013

Captured human motion data has been widely utilized for understanding the mechanism of human motion and synthesizing the animation of virtual characters. Searching for desired motions from given motion data is an important prerequisite of analyzing and editing those selected motions. This paper presents a new method of content-based motion retrieval without the need of additional metadata such as keywords. While existing search methods have focused on skeletal configurations of body pose or planar trajectories of locomotion, our method receives a three-dimensional trajectory as its input query and retrieves a set of motion intervals in which the trajectories of body parts such as hands, foods, and pelvis are similar to the input trajectory. In order to allow the user to intuitively sketch spatial trajectories, we used the Leap Motion controller that can precisely trace finger movements as the input device for our experiments. We have evaluated the effectiveness of our approach by conducting a user study in which the users search for dozens of pre-selected motions from baseketball motion data including a variety of moves such as dribbling and shooting.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.264-271
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• 2017

This paper presents air traffic control simulation model for generating 4D trajectory, and aircraft dynamic model based on 4D trajectory information. With aircraft parameters from BADA and Total Energy Model, the trajectory is defined through modified Bezier curve and the simulation supports two aircraft control methods based on controlled time of arrival (CTA) or airspeed. The simulation results shown that flight time and path were almost identical to the defined trajectory, and derived the differences of each control methods according to wind conditions. Based on the simulation model developed in this study, it is expected to be applied to various air traffic management researches. Future studies will focus on applying optimization techniques in order to minimize the difference between generated trajectories and actual flight routes. This work will increase utilization of developed simulation futhermore.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.5
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• pp.402-409
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• 2018

In this paper, we propose a lunar landing scenario of a robotic lunar landing mission and implements an optimal landing trajectory at the powered descent phase based on the proposed scenario. The change of attitude of the lunar lander in the power descent phase affects not only the amount of fuel used but also sensor operation of image based navigation. Therefore, the attitude angular velocity is included in the cost function of the optimal control problem to minimize the unnecessary attitude change when the optimal landing trajectory generates at powered descent phase of the lunar landing. The influence of the change of attitude angular velocity on the optimal landing trajectory are analyzed by adjusting the weight of the attitude angular velocity. Based on the results, we suggest the proper weight to generate the optimal landing trajectory in order to minimize the influence of the attitude angular velocity.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.145-147
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• 2003

시간이 흐름에 따라 위치가 연속적으로 변경되는 객체를 이동 객체(Moving Objects)라고 한다. 이러한 이동 객체의 대용량 궤적 정보를 효율적으로 검색하기 위해서 색인이 필요하며 대표적인 색인으로 TB-tree가 있다. 그러나 전통적인 공간 색인인 R-tree 기반의 TB-tree는 엄격한 궤적 보존 정책에 의해 레코드가 삽입될 때마다 해당 레코드의 선행자(predecessor)를 포함하는 단말 노드를 검색해야 하며, 레코드 삽입으로 인한 단말 노드 MBB의 변경을 해당 단말 노드에서부터 루트 노드까지 반영해야하는 갱신 부하를 가지고 있다. 본 논문에서는 대용량 궤적 정보의 효율적인 색인을 위한 TB-tree 갱신 기법을 제안한다. 본 기법은 앞으로 삽입될 이동 객체의 궤적을 포함하는 예상된 MBB(EMBB: Expected Minimum Bounding Box)를 트리에 먼저 반영한다. 그 후 새로운 레코드가 삽입될 때마다 중간 노드의 MBB를 갱신하지 않고, 삽입되는 레코드의 MBB가 EMBB을 벗어났을 때 EMBB를 재설정하여 실제로 삽입된 레코드의 MBB와 재설정된 EMBB를 포함하도록 중간 노드의 MBB를 조정하므로 TB-tree의 MBB 조정 횟수를 줄인다. 또한 TB-tree에 선행자를 포함하는 단말 노드를 직접적(direct)으로 접근하기 위하여 별도의 선행자 테이블(Predecessor Table) 구조를 두어 레코드 삽입을 위해 선행자를 포함하는 단말 노드의 검색비용을 줄여 전체적인 색인 갱신 비용이 감소된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.402-409
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• 2007

In this paper recognized for trajectory using Condensation algorithm. In this pater used fuzzy controller for recognized trajectory using fuzzy reasoning. The fuzzy system tract to the three-dimensional space for raw and roll movement. The joint angle ${\theta}_1$ of the manipulator rotate from $0^{\circ}\;to\;360^{\circ}$, and the joint angle ${\theta}_2$ rotate from $0^{\circ}\;to\;180^{\circ}$. The moving object of velocity display for recognition without error using Condensation algorithm. The tracking system demonstrated the reliability of proposed algorithm through simulation against used trajectory.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.771-781
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• 2022

Sequential convex programming based performance analysis of the designed UAV is performed. The nonlinear optimization problems generated by aerodynamics are approximated to socond order program by discretization and convexification. To improve the performance of the algorithm, the solution of the relaxed problem is used as the initial trajectory. Dive trajectory optimization problem is analyzed through iterative solution procedure of approximated problem. Finally, the maximum final velocity according to the performance of the actuator model was compared.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.648-656
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• 2001

In this paper, we propose a new feature-based vehicle tracking system using trajectory matching for intelligent traffic surveillance. The proposed system consists of three parts: feature extraction, feature tracking, and feature grouping using trajectory matching. For feature extraction and feature tracking, features of vehicles are selected based on the measure of cornerness and are tracked using linear Kalman filtering. We then group features from the same vehicle in the grouping step. We suggest a new grouping algorithm using the spatial information of features and trajectory matching to solve the over-grouping Problems of the feature-based tracking method. Finally, our proposed tracking system demonstrates good performance for typical traffic scenes with partial occlusion and neighboring conditions.

• The KIPS Transactions:PartD
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• v.16D no.3
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• pp.317-326
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• 2009

Recently, there have been many research efforts proposed on trajectory information. Most of them mainly focus their attention on those objects moving in Euclidean space. Many real-world applications such as telematics, however, deal with objects that move only over road networks, which are highly restricted for movement. Thus, the existing methods targeting Euclidean space cannot be directly applied to the road network space. This paper proposes a new clustering scheme for a large volume of trajectory information of objects moving over road networks. To the end, we first define a trajectory on a road network as a sequence of road segments a moving object has passed by. Next, we propose a similarity measurement scheme that judges the degree of similarity by considering the total length of matched road segments. Based on such similarity measurement, we propose a new clustering algorithm for trajectories by modifying and adjusting the FastMap and hierarchical clustering schemes. To evaluate the performance of the proposed clustering scheme, we also develop a trajectory generator considering the observation that most objects tend to move from the starting point to the destination point along their shortest path, and perform a variety of experiments using the trajectories thus generated. The performance result shows that our scheme has the accuracy of over 95% in comparison with that judged by human beings.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.329-330
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• 2007

지능형 로봇에서 환경인식과 이러한 환경에 따른 행동 결정능력은 로봇이 필수적으로 갖추어야 할 기능이다. 본 논문은 이족로봇 플랫폼에서 비전기반 환경인식과 이를 통한 안정적인 보행 제어시스템을 제안한다. 비전기반 환경인식 시스템은 움직임 모델을 이용한 로봇 자체 움직임 보정 모듈, Adaboost를 이용한 장애물 영역 추출, PCA를 이용한 장애물 특징 추출, Hierarchical SVM을 이용한 장애물 인식 모듈로 구성되어 있으며, 이러한 환경 인식 시스템으로부터 보행 제어 시스템은 상황에 맞는 안정적이 보행 궤적을 생성한다. 보행 제어 시스템은 neural network을 이용하여 보행 궤적 생성 모듈과 보행 오차를 보정하기 위한 fuzzy 제어기 모듈로 구성되어 있다. 본 시스템을 제작한 로봇에 적용한 결과 보다 안정적인 보행을 할 수 있었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.53-54
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• 2018

본 논문은 ROS 프레임워크를 기반으로 4-자유도를 가진 로봇 팔의 Pick-and-Place 동작 제어를 구현하고, 틱택토 게임에 적용한 사례를 제시한다. 로봇 팔의 Pick-and-Place 동작 제어는 움직임 궤적 계획, 충돌 회피 그리고 역기구학 모델링 연산들과 이를 이용한 복잡한 제어 과정을 요구한다. ROS 프레임워크는 간단한 인터페이스 통해 로봇 팔의 동작을 용이하게 제어할 수 있도록 일련의 연산들과 제어 동작을 통합하여 MoveIt 패키지를 제공하고 있으며, 본 논문은 이 패키지를 기반으로 4-자유도의 로봇 팔에 대한 동작 제어 모듈을 구현하였다. 또한 이를 틱택토 게임에 적용하여 로봇 팔을 적절히 제어함을 확인하였다.