• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.215-217
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• 2010

IT융합의 중요성이 강조되고 있는 IT 지식정보화 사회에 지능형 로봇의 발전은 끝없이 연구되고 있다. 미래 인간사회에 로봇이 미치는 영향은 아주 클 것으로 예상하고 있으며, 인간의 실생활과 로봇의 가상공간 세계는 점점 일체화 되어 갈 것으로 예측된다. 따라서 인간은 로봇의 활동과 행동을 좀 더 구체적이고 자세하게 제어할 필요가 있다. 최근 현실세계를 가상공간의 세계로 표현하고자 하는 연구가 활발히 진행되고 있으며, 가상공간을 활용한 미래의 세상 환경은 점점 많아 질 것으로 예상한다. 따라서 본 논문에서는 지능로봇 시뮬레이션 맵 자동생성을 위한 제어 동기화 설계를 연구하였다. 현실세계의 실제 로봇과 가상공간의 시뮬레이션 로봇을 동기화하여 하드웨어 로봇의 움직임에 따라 가상공간의 로봇이 맵을 자동으로 생성시킬 수 있는 방법을 연구하고 설계하여 실험하였다. 실제 로봇의 움직임을 3차원 가상공간으로 자동 생성하게 함으로서, 로봇의 제어를 좀 더 지능화 시킬 수 있을 뿐아니라, 여러 다양한 시뮬레이션 테스트 환경으로 응용할 수 있는 큰 장점이 있다. 또한 로봇을 활용한 가상공간 세계의 시뮬레이션은 미래 인간과 로봇이 함께하는 공존세계에 큰 역할을 할 수 있을 것으로 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.413-415
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• 2009

최근 지능형 로봇의 필요성과 활용성이 증가하면서 로봇의 형태와 사용 방법이 다양하게 발전하고 있다. 하드웨어적인 로봇의 발전은 과거부터 현재까지 많은 발전을 거듭해 왔으나, 로봇의 지능과 기능을 모듈화 하여 서비스 할 수 있는 방법은 많이 연구되지 못하였다. 지능로봇 서비스는 로봇의 형태와 사용 방법에 따라 서비스를 다르게 적용할 수 있을 뿐만 아니라, 다양한 응용 개발이 가능하여 쉽고 빠르게 로봇에 적용이 가능하다. 또한 컴포넌트 기반의 시뮬레이션 서비스를 개발함으로서 사용자(End User)의 설계 및 개발 시간 단축과 테스트 및 시뮬레이션 시간을 획기적으로 단축할 수 있다. 따라서 본 논문에서는 VPL 활용을 위한 지능로봇 시뮬레이션 서비스 컴포넌트 개발 연구 방법을 소개하고 제안한다. VPL은 인간친화적인 GUI환경으로 로봇 시뮬레이션 프로그램을 개발 할 수 있는 RDS 프로그램 방법이며, 다양한 서비스 개발을 통해 다양한 환경 그리고 다양한 시뮬레이션 로봇의 실험이 가능하다. 본 연구에서는 C# 언어를 사용하여 지능로봇 서비스 컴포넌트 개발 사례를 소개하고 실제 로봇 시뮬레이션 프로그램에 적용하여 실험하였다. 따라서 향후 많은 로봇 서비스 컴포넌트의 응용 개발과 로봇 산업, 교육 분야에 큰 도움이 될 것으로 기대한다.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.127-134
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• 2023

Recently, various input shapers have been introduced to reduce residual vibrations of flexible robots. However, there have been no studies on the design of an input shaper that can suppress residual vibration at an arbitrarily specified duration. In this paper, a novel input shaper called an SD (specified-duration) shaper is proposed for an undamped or underdamped system, which can suppress residual vibration at an arbitrarily given specified duration. If the specified duration is larger than a half period, a positive SD shaper composed of all positive impulses is designed, and if the specified duration is smaller than a half period, a negative SD shaper including a negative impulse is designed. As the specified duration is increased every half period after a half period, the number of impulses of the positive SD shaper is increased one by one, and the robustness of the SD shaper to modeling errors is increased. The performance of the SD shaper is analyzed through simulation studies for an undamped and underdamped second-order systems. The validity of the SD shapers is demonstrated experimentally using an experimental device that can generate container transport motions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.89-95
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• 2023

In recent decades, human action recognition (HAR) has demonstrated potential applications in sports analysis, human-robot interaction, and large-scale signage content. In this paper, spatial temporal attention graph convolutional network (STAGCN)-based HAR system is proposed. Spatioal-temmporal features of skeleton sequences are assigned different weights by STAGCN, enabling the consideration of key joints and viewpoints. From simulation results, it has been shown that the performance of the proposed model can be improved in terms of classification accuracy in the NTU RGB+D dataset.

• Journal of Information Processing Systems
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• v.19 no.6
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• pp.730-744
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• 2023

The topic of this paper is the recognition of human activities using egocentric vision, particularly captured by body-worn cameras, which could be helpful for video surveillance, automatic search and video indexing. This being the case, it could also be helpful in assistance to elderly and frail persons for revolutionizing and improving their lives. The process throws up the task of human activities recognition remaining problematic, because of the important variations, where it is realized through the use of an external device, similar to a robot, as a personal assistant. The inferred information is used both online to assist the person, and offline to support the personal assistant. With our proposed method being robust against the various factors of variability problem in action executions, the major purpose of this paper is to perform an efficient and simple recognition method from egocentric camera data only using convolutional neural network and deep learning. In terms of accuracy improvement, simulation results outperform the current state of the art by a significant margin of 61% when using egocentric camera data only, more than 44% when using egocentric camera and several stationary cameras data and more than 12% when using both inertial measurement unit (IMU) and egocentric camera data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1094-1103
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• 2012

Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This technology is a software which is to provide the core technology which was suggested by the United state's military M&S standard framework. Simulator, virtual simulation, and inter-connection between military weapons system S/W which executes on network which is M&S's core base technology, and it is a technology which also can be used for various inter-connection between S/W such as game and on-line phone. These days although RTI is used in military war game or tactical training unit field, there is none in Korea. Also, it is used in mobile-game, distribution game, net management, robot field, and other civilian field, but the number of examples are so small and informalized. Through this developing project, we developed the core technique and RTI software and provided performance of COTS level to improve communication algorithms.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.103-108
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• 2019

Non-equilibrium molecular dynamics simulation on the thermal boundary resistance(TBR) of an aluminum(Al)/silicon(Si) interface was performed in the present study. The constant heat flux across the Si/Al interface was simulated by adding the kinetic energy in hot Si region and removing the same amount of the energy from the cold Al region. The TBR estimated from the sharp temperature drop at the interface was independent of heat flux and equal to $5.13{\pm}0.17K{\cdot}m^2/GW$ at 300K. The simulation result was experimentally confirmed by the time-domain thermoreflectance technique. A 90nm thick Al film was deposited on a Si(100) wafer using an e-beam evaporator and the TBR on the film/substrate interface was measured using the time-domain thermoreflectance technique based on a femtosecond laser system. A numerical solution of the transient heat conduction equation was obtained using the finite difference method to estimate the TBR value. Experimental results were compared to the prediction and discussions on the nanoscale thermal transport phenomena were made.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.37-43
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• 2010

In field, one can observe without difficulties that two flocks are intersected or combined with each other. For example, a fish flock in a stream separates into two part by obstacles (e.g. stone) and rejoins behind the obstacles. The dynamics of two flocks guided by their leader were studied in the situation where the flocks cross each other with a crossing angle, ${\theta}$, between their moving directions. Each leader is unaffected by its flock members whereas each member is influenced by its leader and other members. To understand the dynamics, I investigated the order parameter, ${\phi}$, defined by the absolute value of the average unit velocity of the flocks' members. When the two flocks were encountered, the first peak in ${\phi}$ was appeared due to the breaking of the flocks' momentum balance. When the flocks began to separate, the second peak in ${\phi}$ was observed. Subsequently, erratic peaks were emerged by some individuals that were delayed to rejoin their flock. The amplitude of the two peaks, $d_1$ (first) and $d_2$ (second), were measured. Interestingly, they exhibited a synchronized behavior for different ${\theta}$. This simulation model can be a useful tool to explore animal behavior and to develop multi-agent robot systems.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.176-183
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• 2014

Three-phase four-wire distribution systems are used for both three-phase three-wire loads and single-phase two-wire consumer appliances in South Korea, Myanmar and other countries. Unbalanced load conditions frequently occur in these distribution systems. These unbalanced load conditions cause unbalanced voltages for three-phase and single-phase loads, and increase the loss in the distribution transformer. In this paper, we propose constant DC capacitor voltage control based strategy for the active load balancer (ALB) in the three-phase four-wire distribution systems. Constant DC capacitor voltage control is always used in active power line conditioners. The proposed control strategy does not require any computation blocks of the active and reactive currents on the distribution systems. Balanced source-side currents with a unity power factor are obtained without any calculation block of the unbalanced active and reactive components on the load side. The basic principle of the constant DC capacitor voltage control based strategy for the ALB is discussed in detail and then confirmed by both digital computer simulations using PSIM software and prototype experimental model. Simulation and experimental results demonstrate that the proposed control strategy for the ALB can balance the source currents with a unity power factor in the three-phase four-wire distribution systems.

• The Journal of the Acoustical Society of Korea
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• v.30 no.3
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• pp.142-148
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• 2011

The final aim of the present study is to develop the intelligent robot, emulating human synesthetic skills which make it possible to associate a color image with a specific sound. This can be done on the basis of the mutual conversion between color image and sound. As a first step of the final goal, this study focused on a basic system using a conversion of color image into sound. This study describes a proposed method to convert color image into sound, based on the likelihood in the physical frequency information between light and sound. The method of converting color image into sound was implemented by using HSI histograms through RGB-to-HSI color model conversion, which was done by Microsoft Visual C++ (ver. 6.0). Two different color images were used on the simulation experiments, and the results revealed that the hue, saturation and intensity elements of each input color image were converted into fundamental frequency, harmonic and octave elements of a sound, respectively. Through the proposed system, the converted sound elements were then synthesized to automatically generate a sound source with wav file format, using Csound.