• 한국정보통신학회논문지
• /
• 제12권8호
• /
• pp.1363-1369
• /
• 2008

게임과 캐릭터 애니메이션의 발전으로 캐릭터의 동작을 사실적으로 표현하는 기술은 다양한 분야에서 요구되었다. 이에 따라 사실적인 캐릭터 동작을 생성하는 다양한 방법에 대한 연구가 활발히 진행되어 왔다. 캐릭터의 동작을 생성하는 방법은 숙달된 사용자가 캐릭터의 움직임을 지정하는 방식과 동역학 등의 물리적 법칙을 활용하여 동작을 시뮬레이션하는 방법, 모션 캡쳐 등과 같은 입력장치를 이용하여 배우의 움직임을 측정하여 데이터로 만드는 방법 등이 있다. 이러한 기법들을 이용하여 생성된 동작들은 각각의 방법마다 나름의 장점이 있지만, 제어가 힘들다는 공통적인 단점을 가지고 있다. 사용자에게 가장 편리한 제어를 제공하기 위해서는 사실적인 동작을 고수준 매개변수를 이용하여 생성할 수 있어야 하며, 이러한 동작의 변형 역시 고수준 매개 변수를 통해 이루어져야 한다. 본 논문은 고수준 매개변수(high-level parameter)를 이용하여 캐릭터의 동작을 효율적으로 제어할 수 있는 자동화된 도구의 개발 방법을 제안하며, 이러한 자동 동작 생성 도구를 활용하여 실제 게임을 제작하는 데에 필요한 기술을 소개한다.

• Nuclear Engineering and Technology
• /
• 제53권3호
• /
• pp.825-832
• /
• 2021

A simulation-based approach is proposed to study the protective actions taken by residents during nuclear emergencies using cognitive findings. Human perception-based behaviors are not heavily incorporated in the evacuation study for nuclear emergencies despite their known importance. This study proposes a generic framework of perception-based behavior simulation, in accordance with the ecological concept of affordance theory and a formal representation of affordance-based finite state automata. Based on the generic framework, a simulation model is developed to allow an evacuee to perceive available actions and execute one of them according to Newton's laws of motion. The case of a shadow evacuation under nuclear emergency is utilized to demonstrate the applicability of the proposed framework. The illustrated planning algorithm enables residents to compute not only prior knowledge of the environmental map, but also the perception of dynamic surroundings, using widely observed heuristics. The simulation results show that the temporal and spatial dynamics of the evacuation behaviors can be analyzed based on individual perception of circumstances, while utilizing the findings in cognitive science under unavoidable data restriction of nuclear emergencies. The perception-based analysis of the proposed framework is expected to enhance nuclear safety technology by complementing macroscopic analyses for advanced protective measures.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제11권1호
• /
• pp.59-69
• /
• 2019

This paper focuses on the numerical simulation of ice abrasion induced by unbreakable ice floe. Under the assumption that unbreakable floes behave as rigid body, the Discrete Element Method (DEM) was applied to simulate the interaction between a fixed structure and ice floes. DEM is a numerical technique which is eligible for computing the motion and effect of a large number of particles. In DEM simulation, individual ice floe was treated as single rigid element which interacts with each other following the given interaction rules. Interactions between the ice floes and structure were defined by soft contact and viscous Coulomb friction laws. To derive the details of the interactions in terms of interaction parameters, the Finite Element Method (FEM) was employed. An abrasion process between a structure and an ice floe was simulated by FEM, and the parameters in DEM such as contact stiffness, contact damping coefficient, etc. were calibrated based on the FEM result. Resultantly, contact length and contact path length, which are the most important factors in ice abrasion prediction, were calculated from both DEM and FEM and compared with each other. The results showed good correspondence between the two results, providing superior numerical efficiency of DEM.

• International Journal of Aeronautical and Space Sciences
• /
• 제10권1호
• /
• pp.30-36
• /
• 2009

Many formation guidance laws have been proposed for VAV formation flight. Since most autonomous formation flight methods require various active communication links between the vehicles to know motion information of other vehicles, damage to the receiver or the transmitter and communication delay are critical problem to achieve a given formation flight mission. Therefore, in this point of view, the method that does not need an inter-vehicle communication is preferred in the autonomous formation flight. In this paper, we first summarize the formation guidance law without an inter-vehicle communication using feedback linearization and sliding mode control proposed in previous study. We also propose the modified formation guidance law with robust disturbance observer, which can provide significantly better performance than previously mentioned guidance law in case that other vehicles maneuver with large accelerations. The robust disturbance observer can estimate uncertainties generated by acceleration of leader vehicle. By eliminating the uncertainties using the estimated uncertainties, VAVs are able to achieve the tight formation flight. The performance of the proposed approach is validated by numerical simulations.

• 한국해양공학회지
• /
• 제30권3호
• /
• pp.208-213
• /
• 2016

This paper proposes a potential field-based guidance law for docking a USV (unmanned surface vehicle). In most cases, a USV without side thrusters is an under-actuated system. Thus, there are undockable regions near docking stations where a USV cannot dock to a docking station without causing a collision or backward motion. This paper suggest a guidance law that prevents a USV from enter such a region by decreasing the lateral error to the docking station at the initial stage of the docking process. A Monte-carlo simulation was performed to validate the performance of the proposed method. The proposed method was compared to conventional guidance laws such as pure pursuit guidance and pure/lead pursuit guidance. As a result, the collision angle and lateral distance error of proposed method tended to have lower values compared to conventional methods.

• 한국수학사학회지
• /
• 제22권3호
• /
• pp.273-292
• /
• 2009

뉴턴과 아인슈타인의 시공간에 대한 표준적 해석에 의하면 독립적으로 존재하는 시공간이란 존재자가 물체의 운동을 인과적으로 설명한다. 이 논문은 뉴턴과 아인슈타인의 시공간을 해석하는 이 견해를 비판적으로 고찰한다. 이두 이론에서 시공간을 해석하는 최근 과학사와 과학철학의 연구를 중심으로 필자는 시공간 구조가 운동법칙의 부산물이지 그 반대가 아님을 주장한다. 이러한 시공간의 동역학적 견해를 통해 시공간이 가지는 인과적 속성이 뉴턴물리학에서 아인슈타인 물리학으로의 이론변화의 발전에 의미 있는 기능을 하지 못하였음을 주장할 것이다.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제54권6호
• /
• pp.376-382
• /
• 2005

In this paper, practical biped humanoid robot is presented, designed, and modeled by fuzzy system. The humanoid robot is a popular research area in robotics because of the high adaptability of a walking robot in an unstructured environment. But owing to the lots of circumstances which have to be taken into account it is difficult to generate stable and natural walking motion in various environments. As a significant criterion for the stability of the walk, ZMP (zero moment point) has been used. If the ZMP during walking can be measured, it is possible for a biped humanoid robot to realize stable walking by a control method that makes use of the measured ZMP. In this study, measuring the ZMP trajectories in real time situations throughout the whole walking phase on the flat floor and slope are conducted. And the obtained ZMP data are modeled by fuzzy system to explain empirical laws of the humanoid robot. By the simulation results, the fuzzy system can be effectively used to model practical humanoid robot and the acquired trajectories will be applied to the humanoid robot for the human-like walking motions.

• 한국산업융합학회 논문집
• /
• 제18권3호
• /
• pp.139-149
• /
• 2015

In this paper, we describe a new approach to perform real-time implementation of an robust controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved direct Lyapunov method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for robot manipulator consisting of dual arm with eight degrees of freedom at the joint space and cartesian space.

• International Journal of Aeronautical and Space Sciences
• /
• 제15권4호
• /
• pp.412-418
• /
• 2014

This paper describes the development of variable stability system (VSS) control laws for the KFA-i to simulate the dynamics of KFA-m aircraft. The KFA-i is a single engine, Class IV aircraft and was selected as an in-flight simulator (IFS) aircraft, whereas the KFA-m is a simulated aircraft that is based on the F-16 aircraft. A 6-DoF math model of KFA-i aircraft was developed, linearized, and separated into longitudinal and lateral motion for VSS control law synthesis. The KFA-i aircraft has five primary control surfaces: two flaperons, two all movable horizontal tails, and one rudder. Flaperons are used for load control, the horizontal tails are used for pitch and roll rate control, and the rudder is used for yaw rate control. The developed VSS control law can simulate four parameters of the KFA-m aircraft simultaneously, such as pitch, roll, yaw rates, and load. The simulation results show that KFA-i follows the responses of KFA-m with high accuracy.

• Journal of Astronomy and Space Sciences
• /
• 제32권4호
• /
• pp.419-425
• /
• 2015

In this study, a new idea for developing a space scale for measuring mass in a microgravity environment was proposed by using the inertial force properties of an object to measure its mass. The space scale detected the momentum change of the specimen and reference masses by using a load-cell sensor as the force transducer based on Newton's laws of motion. In addition, the space scale calculated the specimen mass by comparing the inertial forces of the specimen and reference masses in the same acceleration field. By using this concept, a space scale with a capacity of 3 kg based on the law of momentum conservation was implemented and demonstrated under microgravity conditions onboard International Space Station (ISS) with an accuracy of ${\pm}1g$. By the performance analysis on the space scale, it was verified that an instrument with a compact size could be implemented and be quickly measured with a reasonable accuracy under microgravity conditions.