• 한국재료학회지
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• 제13권4호
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• pp.259-265
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• 2003

For the aim of thin microwave absorbers used in mobile telecommunication frequency band, this study proposed a high permittivity dielectrics(λ/4 spacer) coated with ITO thin films of 377 $\Omega$/sq(impedance transformer). High frequency dielectric properties of ferroelectric ceramics, electrical properties of ITO thin films and microwave absorbing properties of ITO/dielectrics were investigated. Ferroelectric materials including $BaTiO_3$(BT), 0.9Pb($Mg_{1}$3/Nb$_{2}$3/)$O_3$-0.1 $PbTiO_3$(PMN-PT), 0.8 Pb (Mg$_{1}$3/$Nb_{2}$3/)$O_3$-0.2 Pb($Zn_{1}$3$_Nb{2}$3/)$O_3$(PMN-PZN) were prepared by ceramic processing for high permittivity dielectrics,. The ferroelectric materials show high dielectric constant and dielectric loss in the microwave frequency range. The microwave absorbance (at 2 ㎓) of BT, 0.9PMN-0.1PT, and 0.8PMN-0.2PZN were found to be 60%(at a thickness of 3.5 mm), 20% (2.5 mm), and 30% (2.5 mm), respectively. By coating the ITO thin films on the ferroelectric substrates with λ/4 thickness, the microwave absorbance is greatly improved. Particularly, when the surface resistance of ITO films is closed of 377 $\Omega$/sq, the reflection loss is reduced to -20 ㏈(99% absorbance). This is attributed to the wave impedance matching controlled by ITO thin films at a given thickness of high permittivity dielectrics of λ/4 (3.5 mm for BT, 2.5 mm for PMN-PT and PMN-PZN at 2 ㎓). It is, therefore, successfully proposed that the ITO/ferroelectric materials with controlled surface resistance and high dielectric constant can be useful as a thin microwave absorbers in mobile telecommunication frequency band.

• 디지털산업정보학회논문지
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• 제5권3호
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• pp.39-45
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• 2009

In this paper we present a cleaning robot system for an autonomous mobile robot. Our robot performs goal reaching tasks into unknown indoor environments by using sensor fusion. The robot's operation objective is to clean floor or any other applicable surface and to build a map of the surrounding environment for some further purpose such as finding the shortest path available. Using its cleaning robot system for an autonomous mobile robot can move in various modes and perform dexterous tasks. Performance of the cleaning robot system is better than a fixed base redundant robot in avoiding singularity and obstacle. Sensor fusion using the clean robot improves the performance of the robot with redundant freedom in workspace and Map-Building. In this paper, Map-building of the cleaning robot has been studied using sensor fusion. A sequence of this alternating task execution scheme enables the clean robot to execute various tasks efficiently. The proposed algorithm is experimentally verified and discussed with a cleaning robot, KCCR.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.1008-1009
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• 2017

본 연구는 게임을 비롯한 많은 콘텐츠에서 활용하기 위한 GPU기반 사실적 물 애니메이션 기법을 제안한다. 물 표면은 반사 및 투사와 같은 물리적 현상이 일어나며, 시점에 따른 반사와 투사의 정도가 자동적으로 조절되어야 한다. 본 논문에서는 GPU 프레임 버퍼를 이용한 렌더투텍스처 방법을 이용하여 반사 및 투사결과를 텍스처로 저장하였으며, 이 저장된 데이터에 대한 UV좌표 값을 변경함으로서, 자연스러운 물결의 모습을 표현하였다. 또한 투사 및 반사의 정도가 프레넬(Fresnel) 공식을 통해 자동적으로 계산되도록 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.729-734
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• 2005

One of the important research issues in mobile robot is how to detect the 3D environment fast and accurately, and recognize it. Sensing methods of utilizing laser structured light and/or stereo vision are representatively used among a number of methodologies developed to date. However, the methods are still in need of achieving high accuracy and reliability to be used for real world environments. In this paper to implement a new robotic environmental sensing algorithm is presented by combining the information between intensity image and that of laser structured light image. To see how effectively the algorithm applied to real environments, we developed a sensor system that can be mounted on a mobile robot and tested performance for a series of environments.

• 제어로봇시스템학회논문지
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• 제16권4호
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• pp.361-367
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• 2010

This paper reports the development of a mobile robot for patrol using a single laser range finder. A Laser range finder is useful for outdoor environment regardless of illumination change or various weather conditions. In this paper we combined the motion control of the mobile robot and the algorithm for detecting the outdoor environment. For obstacle avoidance, we adopted the Vector Field Histogram algorithm. A laser range finder is mounted on the mobile robot and looking down the road with a small tilt angle. We propose an algorithm for detecting the surface of the road. The outdoor patrol robot platform is equipped with a DGPS system, a gyro-compass sensor, and a laser range finder. The proposed obstacle avoidance and road detection algorithms were experimentally tested in success.

• 제어로봇시스템학회논문지
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• 제16권11호
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• pp.1038-1043
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• 2010

In this paper, an adaptive sliding-mode formation control and collision avoidance are proposed for electrically driven nonholonomic mobile robots with model uncertainties and external disturbances. A sliding surface based on the leader-follower approach is developed to achieve the desired formation in the presence of model uncertainties and disturbances. Moreover, by using the collision avoidance function, the mobile robots can avoid the obstacles successfully. Finally, simulations illustrate the effectiveness of the proposed control system.

• 수산해양기술연구
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• 제52권2호
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• pp.79-87
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• 2016

Mobile fish-cage was developed assuming a cage net with an enclosed area, which and estimated the hydrodynamic characteristics of the cage through the model experiment. Flux-shielding plates, installed in the bow were compared with the resistance test carried out by making a hole, bilge keel and stud, and basic block flow rate consisting of the results to a flat surface plate. The experimental results confirmed the improved resistance performance effect of 3~6% in the bilge keel and the stud form. To assess the stability of the fish-cage, evaluation of the stability in accordance with the stability criteria for determining the floating docks had confirmed that it satisfied the static stability performance under operating conditions at sea.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.532-535
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• 2003

In this paper, we made study for plastic chip antenna, the plastic is Formax with the circle of PVC and its electric characteristics are dielectric constant 1.9, surface current $10{\Omega}$. The proposed antenna same as the conventional antenna are usually constructed with ceramic chip, which are not fragile in nature and don't tend to break easily. Therefore the proposed antenna with its advantage are attractive for application in mobile antenna. We study the dual-band plastic chip antenna resonated at 800Mhz and 1800Mhz. From this study results, we feel confident of application for mobile phone antenna.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1251-1253
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• 1996

The vision processing system for mobile robots requires real time processing and reliability for the purpose of safe navigation. But, general types of vision systems are not appropriate owing to the correspondence problem which correlates the points out of two images. To determine the obstacle area, we use correspondences of line segments between two perspective images sequentially acquired by camera. To simplify the correspondence, the matching of line segments are performed in the navigation space, based on the assumption that mobile robot should be navigated in the flat surface and the motion of mobile robot between two frames should be approximately known.

• 한국산업융합학회 논문집
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• 제22권4호
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• pp.415-425
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• 2019

This study proposes a new approach to control Moving Stuff Action Through Iterative Learning robot with dual arm for smart factory. When robot moves object with dual arm, not only position of each hand but also contact force at surface of an object should be considered. However, it is not easy to determine every parameters for planning trajectory of the an object and grasping object concerning about variety compliant environment. On the other hand, human knows how to move an object gracefully by using eyes and feel of hands which means that robot could learn position and force from human demonstration so that robot can use learned task at variety case. This paper suggest a way how to learn dynamic equation which concern about both of position and path.