• Journal of Biosystems Engineering
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• 제32권3호
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• pp.173-178
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• 2007

This research was conducted to develop and analyze a wireless monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to evaluate the performance between a wired monitoring system and it. This study used the AP (Access Point), the RS-285 to RS-232 converter, RS-232 to Ethernet converter, PICBASIC board and upgraded lump image processing method to change wired monitoring system into wireless monitoring system. The system was tested at a pilot farm and farm layer house. Results showed that monitoring judgement success rate at a pilot farm on normal cage (without SDL) was 82.3% and that on abnormal cage (with SDL) was 87.5%, respectively. And communication performance test results showed at farm layer house was $700{\sim}900$ kbps while equipments operated. There were dropped slightly than performance of wired monitoring system, however, the quantity was too small to make a significant difference of performance of the controling system developed for wireless communication.

• 한국통신학회논문지
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• 제37권8B호
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• pp.706-711
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• 2012

기존의 LED (Light Emitting Diode)를 이용한 가시광 통신방식은 주로 수 m 의 짧은 전송거리와 수백 Mb/s 이하의 낮은 전송속도를 보여왔다. 이를 타개하기 위하여 본 논문에서는 MIMO (Multiple-Input Multiple-Output) 기술을 가시광 통신에 적용하고자 하는 연구를 수행하였다. 빛은 RF 주파수와는 물리적 특성이 다르기 때문에 기존의 RF 주파수에서 사용되던 MIMO 기술의 이론을 그대로 가시광 통신에 적용하기는 힘들다. 따라서, 본 논문에서는 렌즈를 이용하여 물리적으로 광신호를 분리하고, 이미지 센서를 수신기로 사용하여 MIMO 기술을 구현하는 방식을 채택하였다. 본 논문에서는 상용 이미지센서를 이용하여 채널당 200 bit/s의 전송속도 및 전송거리 10.5 m의 장거리 $2{\times}2$ MIMO LED 무선 가시광 통신 실험을 구현하였다.

• 한국통신학회논문지
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• 제30권9A호
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• pp.867-875
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• 2005

본 논문은 NRD 가이드를 이용하여 10km이상의 장거리 무선통신이 가능한 밀리미터파 대역용 FM 송신기 및 수신기를 제작하였다. 40GHz 사용주파수의 반파장 크기의 간격을 가지는 상하도체판 사이에 PTEE 유전체선로상에 건발진기, FM변조기 및 안테나로 구성된 FM 송신기를 제작하고, 동일한 간격을 가지는 상하도체판 사이에 국부발진용 건발진기, 밸런스믹서, 3dB 방향성결합기 및 안테나로 구성한 FM 수신기를 각각 제작하였다. 또한 제작된 FM송신기 및 수신기를 이용하여 무선통신 영상전송시험을 실시하였다. 이때 전송거리 10km의 시험거리에서 영상신호를 송신측에서 보낸 후 수신측의 TV 수상기를 통해 선명한 영상을 실시간으로 재생할 수 있었다. 이에 개발된 40GHz 대역 FM 송신기 및 수신기는 CATV의 전송이나 광대역 전송이 필요한 무선통신 시스템으로 사용이 가능하며, 장거리 초고속통신망의 연결 장치로 사용될 수 있을 것이다.

• 전자통신동향분석
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• 제36권4호
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• pp.23-33
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• 2021

Wireless communication for train control is an active research field. The World Railway Federation in Europe developed GSM-R, which integrates the GSM-based voice call standard and train control signals. To provide advanced railway services, the LTE-R wireless communication system was developed in Korea for passenger services and wireless image information required by the railroad industry. Recently, direct communication technology for autonomous train driving has been studied to decrease the driving interval, and research is being conducted on a hyperloop train control system that runs at a maximum speed of 1,220km/h in a subvacuum environment of 0.001 atmosphere. In this paper, we summarize the trends in wireless communication technologies used for GSM-R/LTE-R railway systems. For future wireless communication in railway systems, we discuss autonomous train driving and the hyperloop railway control system, define wireless communication technology, and discuss trends in domestic and foreign technologies.

• 한국생산제조학회지
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• 제26권1호
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• pp.121-129
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• 2017

In this study, we investigated a cooperative control system of assembly robots using wireless LAN. We developed two different types of robots to assemble three blocks on a workbench. Robot1 can assemble blocks on a workbench and Robot2 can carry blocks to Robot1. We constructed an ROS-based communication system and shared data. Three blocks and one workbench were recognized by camera-image processing By developing the UI using Windows programming language Visual C#, we evaluated the status of the robots and blocks and controlled the robots. The control system was developed by constructing all elements necessary for cooperative control, such as robot design and fabrication, motor control, ROS-based communication, and image processing. Thus, we completed fundamental tasks required for assembly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.340-342
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• 2007

When a system is teleoperated in the indoor environment through the wireless LAN, the communication time delay that is due to the inherent characteristic and surrounding environment is random and unbounded. The time delay has a significant effect on the stability and performance of the teleoperating system. In this paper, we present the method that is the image compression, measuring time delay and switching control-mode corresponding to time delay automatically, to improve stability and performance, and the simple experiment is conducted to demonstrate the feasibility

• International journal of advanced smart convergence
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• 제8권1호
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• pp.98-105
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• 2019

Energy autonomy is a system that is sustained by energy from an independent and distributed source such as renewable energy. In this paper, we propose a robotic energy autonomy in which a robot obtains energy from a renewable energy source with a limited storage capacity. As an energy transfer method, wireless power transfer is used to solve the problem of the conventional contact charging method, mechanical complexity, and to obtain high energy transfer efficiency, the image information is used to align the transmitting and receiving coils accurately. A small scale thermoelectric energy source with boost converter, battery charger, and wireless power transfer coil is constructed and an actual charging experiment is conducted to verify the proposed autonomy system.

• Journal of Biosystems Engineering
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• 제33권3호
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• pp.196-203
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• 2008

Hybrid robust image processing algorithm to extract visual features of melon during the cultivation was developed based on a wireless tele-operative interface. Features of a melon such as size and shape including position were crucial to successful task automation and future development of cultivation data base. An algorithm was developed based on the concept of hybrid decision-making which shares a task between the computer and the operator utilizing man-computer interactive interface. A hybrid decision-making system was composed of three modules such as wireless image transmission, task specification and identification, and man-computer interface modules. Computing burden and the instability of the image processing results caused by the variation of illumination and the complexity of the environment caused by the irregular stem and shapes of leaves and shades were overcome using the proposed algorithm. With utilizing operator's teaching via LCD touch screen of the display monitor, the complexity and instability of the melon identification process has been avoided. Hough transform was modified for the image obtained from the locally specified window to extract the geometric shape and position of the melon. It took less than 200 milliseconds processing time.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1168-1172
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• 2011

Beam projector is popularly used for presentation. In order to pay attention to local area of the beam projector display, a laser pointer is used together with a pointing device(Mouse). Simple wireless presenter has limited functions of a pointing device such as "go to next slide" or "back to previous slide" in a specific application(Microsoft PowerPoint) through wireless channel; thus, there is inconvenience to do other tasks e.g., program execution, maximize/minimize window etc. provided by clicking mouse buttons. The main objective of this paper is to implement a multi-functional laser-pointer mouse that has the same functions of a computer mouse. In order to get position of laser spot in the projector display, an image processing to extract the laser spot in the camera image is required. In addition, we propose a transformation of the spot position into computer display coordinates to execute mouse functions on computer display.

• 한국멀티미디어학회논문지
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• 제14권6호
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• pp.719-729
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• 2011

본 논문은 무선 이동로봇의 영상에서 빠르고 정확하게 직선을 검출하는 방법에 대한 연구이다. 직선검출 처리시간 향상을 위하여 무선 이동로봇으로부터 전송 받은 영상의 특성을 분석하고 기존의 전처리 방법들 중 효율적인 전처리 방법을 선택하였다. 그리고 직선검출 정확도 향상을 위하여 하프변환의 결과를 저장하는 하프배열에서 지역 최대값을 선택하는 방법을 마스크를 설계하고 하프배열에 적용하여 개선하였다. 무선 이동로봇으로부터 획득한 실험영상을 가지고 실험을 실시하였고 제안방법은 처리시간과 직선검출에 있어 기존 방법들에 비해 좋은 성능을 보였다.