• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.12-19
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• 2009

In the modern UAV systems, the role of radar payload has been increasing with its unique performance of day-and-night operation and see-through capability over hidden obstacles. Contrary to the satellite reconnaissance, UAV is expected to provide high resolution target detection and recognition capability while frequent flight missions would deliver enhanced SAR image and local information over the target area. STK(Satellite Tool Kit) is a professional space-analysis software widely used in all phases of a space system's life cycle. The simulation of STK is efficient and accurate relatively. In this paper, the author attempt to model the UAV operation and measure the expected SAR image quality. STK(Satellite Tool Kit) is employed to analyze UAV operation and produce SAR raw data. A SAR simulator is developed to produce high resolution SAR image for various ground targets.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.125-132
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• 2021

In this paper, We propose a study on the construction of an environment for collaboration in mixed reality and a method for working with wearable IoT devices. Mixed reality is a mixed form of virtual reality and augmented reality. We can view objects in the real and virtual world at the same time. And unlike VR, MR HMD does not occur the motion sickness. It is using a wireless and attracting attention as a technology to be applied in industrial fields. Myo wearable device is a device that enables arm rotation tracking and hand gesture recognition by using a triaxial sensor, an EMG sensor, and an acceleration sensor. Although various studies related to MR are being progressed, discussions on developing an environment in which multiple people can participate in mixed reality and manipulating virtual objects with their own hands are insufficient. In this paper, We propose a method of constructing an environment where collaboration is possible and an interaction method for smooth interaction in order to apply mixed reality in real industrial fields. As a result, two people could participate in the mixed reality environment at the same time to share a unified object for the object, and created an environment where each person could interact with the Myo wearable interface equipment.

• The Journal of Information Technology
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• v.5 no.4
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• pp.45-55
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• 2002

Virtual Reality(VR) is a new technology which makes humans communicate with computer. It allows the user to see, hear, feel and interact in a three-dimensional virtual world created graphically. In this paper, we introduced VR into psychotherapy area and developed VR system for the exposure therapy of acrophobia. Acrophobia is an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used as a treatment. Lately the virtual reality technology has been applied to that kind of anxiety disorders. A virtual environment provides patient with stimuli which arouses phobia, and exposing to that environment makes him having ability to over come the fear. In this study, the elevator stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a feel of phobia and without phobia, heart rate was measured during experiment. And also measured a person's HR after the virtual reality training. In this study, we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.565-568
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• 2005

최근들어 무선 홈 네트워크에 기반한 센서들에 대한 연구가 많이 이루어지고 있다. 무선 환경에서 센서 장치들은 대량의 장치들이 특정 위치가 아닌 편재된 환경에 존재하는 특징을 가진다. 이러한 센서 장치들의 정보를 제어하고 관리하기 위해서는 센서 정보를 활용하는 어플리케이션과 센서 장치 간, 정보를 중계해주고 관리해주는 미들웨어 소프트웨어가 필요하다. 본 논문에서는 어플리케이션과 센서 장치간 정보를 중계하고 관리해주는 미들웨어 소프트웨어를 설계하여 구현하였으며, 향후 다양한 센서 장치와 네트워크 프로토콜을 지원하도록 하여 홈 네트워크 서비스를 실현하는데 도움이 되고자 하였다.

• Journal of KSNVE
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• v.6 no.1
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• pp.65-70
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• 1996

The sensor response of a piezoelectric transducer embedded in a fluid loaded structure is modeled using a hybrid numerical approach. The structure is excited by an obliquely incident acoustic wave. Finite element modeling in the structure and fluid surrounding the transducer region, is used and a plane wave representation is exploited to match the displacement field at the mathematical boundary. On this boundary, continuity of field derivatives is enforced by using a penalty factor and to further achieve transparency at the mathematical boundary, drilling degrees of freedom (d.o.f.) are introduced to ensure continuity of all derivatives. Numerical results are presented for the sensor response and it is found that the sensor at that location is not only non-intrusive but also sensitive to the characteristic of the structure.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.552-555
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• 2019

디지털 트윈이란 현실 세계의 물리적인 사물을 컴퓨터 상에 동일하게 가상화 시키는 기술을 의미하는 것으로, 물리적 사물이나 시스템을 모델링하거나 IoT 기술에 접목되어 활용되고 있는 기술이다. 디지털 트윈 기술은 가상의 모델을 무한정 시뮬레이션을 통해 동작을 튜닝하고 환경변화에 대한 대응을 미리 실험하여 리스크를 최소화할 수 있는 장점을 지닌다. 최근 인공지능이나 기계학습에 관련된 기술들이 주목받기 시작하면서, 이와 같은 물리적인 사물의 모델링 작업을 데이터 기반으로 수행하려는 시도가 증가하고 있다. 특히, 산업현장에서 많이 활용되는 인더스트리 4.0 공장 자동화의 핵심인 협력 로봇의 디지털 트윈을 구축하기 위해서는 로봇의 동작을 인지하는 과정이 필수적으로 요구된다. 그러나 현재 협력 로봇의 동작을 인지하기 위한 시도는 미비하며, 센서 데이터를 기반으로 동작을 역으로 예측하는 기술은 더욱 그렇다. 따라서 본 논문에서는 로봇의 동작을 인지하기 위해 가정용 협력 로봇에서 전류 및 관성 데이터를 수집하기 위한 실험 환경을 구축하고, 수집한 센서 데이터를 기반으로 한 동작 예측 모델을 제안하고자 한다. 제안하는 방식은 로봇의 동작 명령어를 조인트 위치 기반으로 분류하고 전류와 위치 센서 값을 사용하여 학습을 통해 예측하는 방식이다. SVM 을 이용하여 학습한 결과, 모델의 성능은 평균적으로 정확도, 정밀도, 및 재현율이 모두 96%로 평가되었다.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.4
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• pp.11-18
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• 2021

We propose a method that combines learning in a virtual environment and a real environment for indoor autonomous driving through reinforcement learning. In case of learning only in the real environment, it takes about 80 hours, but in case of learning in both the real and virtual environments, it takes 40 hours. There is an advantage in that it is possible to obtain optimized parameters through various experiments through fast learning while learning in a virtual environment and a real environment in parallel. After configuring a virtual environment using indoor hallway images, prior learning was carried out on the desktop, and learning in the real environment was conducted by connecting various sensors based on Jetson Xavier. In addition, in order to solve the accuracy problem according to the repeated texture of the indoor corridor environment, it was possible to determine the corridor wall object and increase the accuracy by learning the feature point detection that emphasizes the lower line of the corridor wall. As the learning progresses, the experimental vehicle drives based on the center of the corridor in an indoor corridor environment and moves through an average of 70 steering commands.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1071-1080
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• 2017

Recently, the terms of the 4th Industrial Revolution and the Smart Factory are often heard through news and media. But most of the companies that are parties are not interested. Because there is no specific guidance on how to build Smart Factory and information about Smart Factory. The built of the Smart Factory should be carried out in accordance with the size of the company considering the purpose of the introduction. In the existing study, they analyzed successful cases of building Smart Factory in Korea As a result, in the case of large-size firms, it is an effective strategy that expanding from a model factory to whole factory for successful Smart Factory building. In addition, in the case of medium and small-size firms, it is an effective strategy that upgrading from low-level step to high-level step for successful Smart Factory building. In this study, selecting medium and small-size firms, and bottleneck section and processes requiring improvement are identified through 3D virtual process design, and then install sensors. Finally, after analyzing the data collected through the sensor, we will improve the process and build Smart Factory with improved productivity.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.403-406
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• 2009

센서 네트워크 환경에서 각 센서 노드는 크기의 제약으로 인해 전력에 대한 한계점이 존재하여 데이터의 전송 및 데이터의 수집에 대한 작동을 최소화해야 한다. 특히, 데이터의 전송은 센서 노드의 전력소모에 큰 영향을 끼친다. 그리고 센서 네트워크에서는 근본적으로 높은 전송 에러율과 센서의 이동으로 인한 문제를 가진다. 본 논문에서는 가상환경에서 움직이거나 시간에 따라서 생기는 장애물에 대한 실질적인 전송 에러율 문제를 해결할 데이터 병합기법을 제안한다. 제안하는 기법은 신뢰성 있는 데이터 병합기법(RDAP : Reliable Data Aggregation Protocol)에 홉 수를 첨가하여 센서들이 예상치 못한 라우팅 경로 재설정으로 인해 센서노드의 센싱 값 손실을 방지할 수 있다.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.619-625
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• 2006

핸드헬드 가상현실 시스템이란 멀티모달 센서와 멀티모달 디스플레이 장치가 내장되어 가상환경을 제공하는 한 손으로 들고 다닐 수 있는 핸드헬드 시스템을 의미한다. 이런 핸드헬드 가상현실 시스템에서는 일반적으로 제한된 입력수단 (예> 버튼, 터치스크린)을 제공하기 때문에 이를 사용해서 3 차원 인터랙션을 행하기가 쉽지 않다. 그래서 본 연구에서는 일반 핸드헬드 기기에 대부분 내장되어 있는 장치인 카메라를 사용해서 핸드헬드 가상환경에서 3 차원 인터랙션을 수행하는 방법을 제안하고 구현, 평가한다.