• 한국인터넷방송통신학회논문지
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• 제24권1호
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• pp.65-74
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• 2024

최근 자율주행 분야에서는 영상 처리 기술이 중요한 역할을 하고 있다. 그 중에서도 영상 식별 기술은 자율주행 차량의 안전성과 성능에 매우 중요한 역할을 한다. 이에 따라 본 논문에서는 융복합 영상 식별 시스템을 개발하여 자율주행 차량의 안전성과 성능을 향상시키는 것을 목표로 한다. 본 연구에서는 다양한 영상 식별 기술을 활용하여 차량주변 환경의 객체를 인식하고 추적하는 시스템을 구축한다. 이를 위해 머신 러닝과 딥 러닝 알고리즘을 활용하며, 이미지처리 및 분석 기술을 통해 실시간으로 객체를 식별하고 분류한다. 또한, 본 연구에서는 영상 처리 기술과 차량 제어 시스템을 융합하여 자율주행 차량의 안전성과 성능을 높이는 것을 목표로 한다. 이를 위해, 식별된 객체의 정보를 차량 제어시스템에 전달하여 자율주행 차량이 적절하게 반응하도록 한다. 본 연구에서 개발된 융복합 영상 식별 시스템은 자율주행 차량의 안전성과 성능을 크게 향상시킬 것으로 기대된다. 이를 통해 자율주행 차량의 상용화가 더욱 가속화될 것으로 기대된다.

• 한국공작기계학회논문집
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• 제16권2호
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• pp.100-105
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• 2007

Electro-rheological(ER) fluid and valve are fabricated and evaluated experimentally in its durability to utilize the hydraulic control systems for long term operation. The two-ports ER valve used in the experiment consist of twelve parallel multi-layer electrodes and provide a restriction to the passage of ER fluid because of the viscous pressure drop and a component induced by the electric field. The durability test of ER valve are performed by measuring the surface roughness of electrodes with variation of an electric field strength and test time(1000 or 1800min.). Also, the shear stress and shear rate are measured to evaluate the durability of ER fluid as function of time. After durability test, ER shear stress increases approximately proportional to the shear rate with applied electric field intensity, In the ER valve, the center line average height roughness(Ra) of copper electrode increases about 1.56 times and ten-point median height roughness(Rz) increases about 2.2 times after the durability test. An understanding of these durability is essential to predicting the service life of ER fluid and valves.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.592-594
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• 2008

The powers used in the robot drive motor system are mostly DC sources such as batteries. Even AC powers in some systems are generated from DC sources by the inverter. It is can be forecasted that the DC-link communications will be widely used invarious industrial application. In this paper a novel BLDC motor drive system by using DC-link communications is proposed. The characteristic of this system is the communication only needs 2 DC lines. There are not additional lines to translate the reference signals and the reliability of the system is enhanced especially in some badly circumstance. The number of lines can be least when applied in the multi motor control system and the slip ring design can be simplified when applied as rotation machine. The reasonableness of proposed motor system is clarified by the PSIM simulation and the hardware prototype.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.463-474
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• 2015

Future Ground Control Stations (GCSs) for Unmanned Aerial Vehicles (UAVs) teleoperation targets better situational awareness by providing extra motion cues to stimulate the vestibular system. This paper proposes a new virtual environment for long range Unmanned Aerial Vehicle (UAV) control via Non-Line-of-Sight (NLoS) communications, which is based on motion platforms. It generates motion cues for the teleoperator for extra sensory stimulation to enhance the guidance performance. The proposed environment employs the distributed component simulation over GSM network as a simulation platform. GSM communications are utilized as a multi-hop communication network, which is similar to global satellite communications. It considers a UAV mathematical model and wind turbulence effects to simulate a realistic UAV dynamics. Moreover, the proposed virtual environment simulates a Multiple Axis Rotating Device (MARD) as Human Machine Interface (HMI) device to provide a complete delay analysis. The demonstrated measurements cover Graphical User Interface (GUI) capabilities, NLoS GSM communications delay, MARD performance, and different software workload. The proposed virtual environment succeeded to provide visual and vestibular feedbacks for teleoperators via GSM networks. The overall system performance is acceptable relative to other Line-of-Sight (LoS) systems, which promises a good potential for future long range, medium altitude UAV teleoperation researches.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.164-171
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• 2010

We have studied the port-automation system which is requested by the steep increment of cost and complexity for processing the freight. This paper will introduce a new algorithm for navigating and controlling the autonomous Guided Vehicle (AGV). The camera has the optical distortion in nature and is sensitive to the external ray, the weather, and the shadow, but it is very cheap and flexible to make and construct the automation system for the port. So we tried to apply to the AGV for detecting and tracking the lane using the CCD camera. In order to make the error stable and exact, this paper proposes new concept and algorithm for obtaining the error is generated by the Virtual Photo-Sensor Array (VPSA). VPSAs are implemented by programming and very easy to use for the various autonomous systems. Because the load of the computation is light, the AGV utilizes the maximal performance of the CCD camera and enables the CPU to take multi-tasks. We experimented on the proposed algorithm using the mobile robot and confirmed the stable and exact performance for tracking the lane.

• 한국정보통신학회논문지
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• 제13권4호
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• pp.828-834
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• 2009

최근 모바일 게임산업은 독립형 게임 위주의 환경에서 수익성이 지속적으로 보장되는 네트워크를 기반으로 한 환경으로 발전해 나가고 있다. 하지만 시중에 서비스되는 대부분의 네트워크 게임의 경우 모바일 대 모바일, PC온라인 대 PC 온라인, 비디오 게임기 대 비디오게임으로 한정되어 있다. 멀티 플랫폼 네트워크게임은 서로 다른 플랫폼과 기기를 사용할 뿐만 아니라, 통신대역폭에 있어서도 차이가 나기 때문에 그 구현에 어려움이 많다. 본 논문은 "눌러 눌러" 라는 아케이드 게임을 통하여 PC 사용자와 모바일 사용자들이 각각 서로 다른 플랫폼 환경에서도 하나의 게임 서버에 접속하여 게임을 즐길 수 있는 멀티 플랫폼 게 임을 소개한다. 본 논문에서는 3세대 멀티 플랫폼 네트워크 게임을 통하여 멀티 플랫폼 게 임의 문제점을 살펴보고, 이를 구현하기 위한 기법들을 설명한다. 본 논문에서 구현한 서버 측의 데이터베이스는 마이크로소프트사의 MS SQL서버를 사용하였으며, PC 게임은 비주얼베이직 환경으로 모바일 게임은 WIPI 환경에서 구현하였다.

• Journal of Multimedia Information System
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• 제4권4호
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• pp.195-204
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• 2017

Mobile robots are used for years as a valuable research and educational tool in form of available open-platform designs and Do-It-Yourself kits. Rapid development and costs reduction of Unmanned Air Vehicles (UAV) and ground based mobile robots in recent years allowed researchers to utilize them as an affordable research platform. Despite of recent developments in the area of ground and airborne robotics, only few examples of Unmanned Surface Vehicle (USV) platforms targeted for research purposes can be found. Aim of this paper is to present the development of open-design USV drone with integrated multi-level control hardware architecture. Proposed catamaran - type water surface drone enables direct control over wireless radio link, separate development of algorithms for optimal propulsion control, navigation and communication with the ground-based control station. Whole design is highly modular, where each component can be replaced or modified according to desired task, payload or environmental conditions. Developed USV is planned to be utilized as a part of the system for detection and identification of marine and lake waste. Cameras mounted to the USV would record sea or lake surfaces, and recorded video sequences and images would be processed by state-of-the-art computer vision and machine learning algorithms in order to identify and classify marine and lake waste.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.110-113
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• 2022

신호를 제어하는 방식은기존의 전통적인 수학적 방식을 이용한 최적화를 넘어 이제 인공지능이 본격적으로 활용되기 시작하는 단계까지 발전하였다. 이에 따라 인공지능을 적용하는 방안에 대해 다양한 연구들이 진행되고 있는데, 현행 연구에서는 주로 좋은 교통 상황에 대한 마땅한 고려 없이 간단히 지체도만을 고려하여 보상함수를 설정하는 방식을 주로 채택하고 있다. 그러나 이 경우 현실성이 떨어지는 신호 제어 방식을 인공지능이 학습할 가능성이 존재한다는 문제점을 지닐 뿐더러, 보상 함수에서 좋다고 평가하는 것이 실질적인 서비스 수준의 정의에 부합하지 않음을 확인할 수 있다. 따라서 본 연구에서는 기존의 보상함수 설정 사례를 분석하고, 개선 방향을 제시하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.649-652
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• 2005

The camera cellular phone has a large portion of cellular phone market in recent year. The variety of a customer demand makes a fast model change and the spatial resolution is changed from VGA to multi-mega pixel. The 1.3 mega pixel (MP) camera cellular phone was first released into the Korean market in October 2003. The major cellular phone companies released a 2MP camera cellular phone that supports zoom function and a 2MP camera cellular phone is settled down with the Korea cellular phone market. It makes a keen competition in price and demands automation for phone camera module. There is an increasing requirement for the automatic assembly to correspond to a fast model change. The hard automation techniques that rely on dedicated manufacturing system are too inflexible to meet this requirement. Therefore in this study, this system is designed with the flexibility concept in order to cope with phone camera module change. The system has a same platform that has X-Y-Z motion or X-Z motion with ${\mu}m$order accuracy. It has a special gripper according to the type of a component to be put together. If the camera model changes, the gripper may be updated to fit for the camera module. The controller of this system acquires the data sets that have the information about the assembly part by the tray. This information is obtained ahead of an inspection step. The controller excludes an inferior part to be assembled by using this information to diminish the inferior goods. The assembly jig used in this system has a function of self adjustment that reduces the tact time and also diminish the inferior goods. Finally, the intelligent assembly system for phone camera module will be designed to get a flexibility to meet model change and a high productivity with a high reliability.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.88-88
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• 2022

Detection of stress responses in crops is important to diagnose crop growth and evaluate yield. Also, the multi-spectral sensor is effectively known to evaluate stress caused by nutrient and moisture in crops or biological agents such as weeds or diseases. Therefore, in this experiment, multispectral images were taken by an unmanned aerial vehicle(UAV) under field condition. The experiment was conducted in the long-term fertilizer field in the National Institute of Crop Science, and experiment area was divided into different status of NPK(Control, N-deficiency, P-deficiency, K-deficiency, Non-fertilizer). Total 11 vegetation indices were created with RGB and NIR reflectance values using python. Variations in nutrient content in plants affect the amount of light reflected or absorbed for each wavelength band. Therefore, the objective of this experiment was to evaluate vegetation indices derived from multispectral reflectance data as input into machine learning algorithm for the classification of nutritional deficiency in rice. RandomForest model was used as a representative ensemble model, and parameters were adjusted through hyperparameter tuning such as RandomSearchCV. As a result, training accuracy was 0.95 and test accuracy was 0.80, and IPCA, NDRE, and EVI were included in the top three indices for feature importance. Also, precision, recall, and f1-score, which are indicators for evaluating the performance of the classification model, showed a distribution of 0.7-0.9 for each class.