• 제목/요약/키워드: Sensor platform

검색결과 779건 처리시간 0.023초

전방향 이동로봇 위치제어 알고리즘과 실험적 검증 (Position Control Algorithm and Experimental Evaluation of an Omni-directional Mobile Robot)

  • 주백석;조강익;성영휘
    • 한국생산제조학회지
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    • 제24권2호
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    • pp.141-147
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    • 2015
  • In this study, a position control algorithm for an omni-directional mobile robot based on Mecanum wheels was introduced and experimentally evaluated. Multiple ultrasonic sensors were installed around the mobile robot to obtain position feedback. Using the distance of the robot from the wall, the position and orientation of the mobile robot were calculated. In accordance with the omni-directional velocity generation mechanism, the velocity kinematics between the Mecanum wheel and the mobile platform were determined. Based on this formulation, a simple and intuitive position control algorithm was suggested. To evaluate the control algorithm, a test bed composed of artificial walls was designed and implemented. While conventional control algorithms based on normal wheels require additional path planning for two-dimensional planar motion, the omni-directional mobile robot using distance sensors was able to directly follow target positions with the simple proposed position feedback algorithm.

Metal Oxide Nanocolumns for Extremely Sensitive Gas Sensors

  • Song, Young Geun;Shim, Young-Seok;Han, Soo Deok;Lee, Hae Ryong;Ju, Byeong-Kwon;Kang, Chong Yun
    • 센서학회지
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    • 제25권3호
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    • pp.184-188
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    • 2016
  • Highly ordered $SnO_2$ and NiO nanocolumns have been successfully achieved by glancing-angle deposition (GLAD) using an electron beam evaporator. Nanocolumnar $SnO_2$ and NiO sensors exhibited high performance owing to the porous nanostructural effect with the formation of a double Schottky junction and high surface-to-volume ratios. When all gas sensors were exposed to various gases such as $C_2H_5OH$, $C_6H_6$, and $CH_3COCH_3$, the response of the highly ordered $SnO_2$ nanocolumn were over 50 times higher than that of the $SnO_2$ thin film. This work will bring broad interest and create a strong impact in many different fields owing to its particularly simple and reliable fabrication process.

Comparison of Artificial Neural Networks for Low-Power ECG-Classification System

  • Rana, Amrita;Kim, Kyung Ki
    • 센서학회지
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    • 제29권1호
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    • pp.19-26
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    • 2020
  • Electrocardiogram (ECG) classification has become an essential task of modern day wearable devices, and can be used to detect cardiovascular diseases. State-of-the-art Artificial Intelligence (AI)-based ECG classifiers have been designed using various artificial neural networks (ANNs). Despite their high accuracy, ANNs require significant computational resources and power. Herein, three different ANNs have been compared: multilayer perceptron (MLP), convolutional neural network (CNN), and spiking neural network (SNN) only for the ECG classification. The ANN model has been developed in Python and Theano, trained on a central processing unit (CPU) platform, and deployed on a PYNQ-Z2 FPGA board to validate the model using a Jupyter notebook. Meanwhile, the hardware accelerator is designed with Overlay, which is a hardware library on PYNQ. For classification, the MIT-BIH dataset obtained from the Physionet library is used. The resulting ANN system can accurately classify four ECG types: normal, atrial premature contraction, left bundle branch block, and premature ventricular contraction. The performance of the ECG classifier models is evaluated based on accuracy and power. Among the three AI algorithms, the SNN requires the lowest power consumption of 0.226 W on-chip, followed by MLP (1.677 W), and CNN (2.266 W). However, the highest accuracy is achieved by the CNN (95%), followed by MLP (76%) and SNN (90%).

재난 모니터링을 위한 편대비행 UAV 네트워크에서 동적 트리 형성 프로토콜 (Dynamic Tree Formation Protocol in UAV Formation Flying Network for Disaster Monitoring)

  • 박진희;김연주;정진욱
    • 한국항행학회논문지
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    • 제16권2호
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    • pp.271-277
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    • 2012
  • 본 논문에서는 재난모니터링, 환경감시 및 재난구호 등의 정보 수집 및 정찰 등의 임무를 수행하는 다수의 UAV들로 구성된 편대비행 네트워크를 위해 동적 트리 형성 프로토콜을 제안하였다. 특히 무선 동적 환경에 적응한 최적의 트리를 구성하기 위한 링크 비용을 구하기 위해 거리에 따른 무선 신호 감쇄현상을 적용하여 Hop-LQI Weight 알고리즘을 고안하였으며 이를 MSP430 K-mote 센서 플랫폼에 TinyOS 코드를 구현하였다. 이를 무선 통신에서 링크 비용 산출 기법인 Minimum LQI 방법과 노드 수에 따른 평균 경로 설정시간을 비교를 통하여 성능을 검증하였다.

새로운 측정장비를 이용한 병렬구조 로봇의 보정에 관한 (Calibration of Parallel Manipulators using a New Measurement Device)

  • 압둘라우프;김성관;류제하
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.1494-1499
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    • 2003
  • Kinematic calibration is a process whereby the actual values of geometric parameters are estimated so as to minimize the error in absolute positioning. Measuring all components of Cartesian posture, particularly the orientation, can be difficult. With partial pose measurements, all parameters may not be identifiable. This paper proposes a new device that can be used to identify all kinematic parameters with partial pose measurements. Study is performed for a six degree-of-freedom fully parallel Hexa Slide manipulator. The device, however, is general and can be used for other parallel manipulators. The proposed device consists of a link with U joints on both sides and is equipped with a rotary sensor and a biaxial inclinometer. When attached between the base and the mobile platform, the device restricts the end-effector's motion to five degree-of-freedom and can measure position of the end-effector and one of its rotations. Numerical analyses of the identification Jacobian reveal that all parameters are identifiable. Computer simulations show that the identification is robust for the errors in the initial guess and the measurement noise.

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Development of LiDAR Simulator for Backpack-mounted Mobile Indoor Mapping System

  • Chung, Minkyung;Kim, Changjae;Choi, Kanghyeok;Chung, DongKi;Kim, Yongil
    • 한국측량학회지
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    • 제35권2호
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    • pp.91-102
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    • 2017
  • Backpack-mounted mapping system is firstly introduced for flexible movement in indoor spaces where satellite-based localization is not available. With the achieved advances in miniaturization and weight reduction, use of LiDAR (Light Detection and Ranging) sensors in mobile platforms has been increasing, and indeed, they have provided high-precision information on indoor environments and their surroundings. Previous research on the development of backpack-mounted mapping systems, has concentrated mostly on the improvement of data processing methods or algorithms, whereas practical system components have been determined empirically. Thus, in the present study, a simulator for a LiDAR sensor (Velodyne VLP-16), was developed for comparison of the effects of diverse conditions on the backpack system and its operation. The simulated data was analyzed by visual inspection and comparison of the data sets' statistics, which differed according to the LiDAR arrangement and moving speed. Also, the data was used as input to a point-cloud registration algorithm, ICP (Iterative Closest Point), to validate its applicability as pre-analysis data. In fact, the results indicated centimeter-level accuracy, thus demonstrating the potentials of simulation data to be utilized as a tool for performance comparison of pointdata processing methods.

소형 다중분광 항공촬영 시스템(PKNU 3호) 개발에 관한 연구 (Research for development of small format multi -spectral aerial photographing systems (PKNU 3))

  • 이은경;최철웅;서영찬;조남춘
    • 한국측량학회:학술대회논문집
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    • 한국측량학회 2004년도 추계학술발표회 논문집
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    • pp.143-152
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    • 2004
  • Researchers seeking geological and environmental information, depend on remote sensing and aerial photographic datum from various commercial satellites and aircraft. However, adverse weather conditions as well as equipment expense limit the ability to collect data anywhere and anytime. To allow for better flexibility in geological and environmental data collection, we have developed a compact, multi-spectral automatic Aerial Photographic system (PKNU2). This system's Multi-spectral camera can record visible (RGB) and infrared (NIR) band (3032*2008 Pixels) images Visible and infrared band images were obtained from each camera respectively and produced color-infrared composite images to be analyzed for the purpose of the environmental monitoring. However this did not provide quality data. Furthermore, it has the disadvantage of having the stereoscopic overlap area being 60% unsatisfied due to the 12 seconds of storage time of each data The PKNU2 system in contrast, photographed photos of great capacity Thus, with such results, we have been proceeding to develop the advanced PKNU2 (PKNU3) system that consists of a color-infrared spectral camera that can photograph in the visible and near-infrared bands simultaneously using a single sensor, a thermal infrared camera, two 40G computers to store images, and an MPEG board that can compress and transfer data to the computer in real time as well as be able to be mounted onto a helicopter platform.

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A Study on the Applications of ICT/IoT for Jeju Haenyeo Culture, an UNESCO Intangible Cultural Heritage

  • Yoo, Jae Ho;Jung, Yeon Kyu
    • 한국IT서비스학회지
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    • 제16권4호
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    • pp.213-222
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    • 2017
  • The advancement of ICT is changing every field of life. It becomes possible with the penetration of personalized devices, that is, smartphone. The boom of IoT will come when there exist diversified and personalized services. In general, we might admit that it is needed that the more privatized services than the overall serviced. Jeju Island is the only one special self-governing province in Republic of Korea and deserves to be proud of the unique culture from its long historical background. One of the very regional culture which performs by women divers, Haenyeo activity or culture, was registered as Intangible Cultural Heritage. When authors were researched Jeju Haenyeo as a worthy reserving service, we recognized that it has never considered to use any point of ICT/IoT yet. Because IoT holds the high potentiality to create any service scenario between interesting groups. We will design a few services for Haenyeo which covers their job territory or daily life, adopts up-to-date technology or method such as sensored network, smart contract and App/Web. In this paper, we intent to show the simplicity and easiness of the application of IoT not to much inconspicuous target. So, we suggest a specialized IoT service for the reservation and promotion of Haenyeo Culture. This service would be composed of sensors, IoT network and App/Web at home and office. This service can be used among interesting groups : Haenyeo, policy maker, manufacturer, service provider and culture consumer.

A Parallel Implementation of Multiple Non-overlapping Cameras for Robot Pose Estimation

  • Ragab, Mohammad Ehab;Elkabbany, Ghada Farouk
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권11호
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    • pp.4103-4117
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    • 2014
  • Image processing and computer vision algorithms are gaining larger concern in a variety of application areas such as robotics and man-machine interaction. Vision allows the development of flexible, intelligent, and less intrusive approaches than most of the other sensor systems. In this work, we determine the location and orientation of a mobile robot which is crucial for performing its tasks. In order to be able to operate in real time there is a need to speed up different vision routines. Therefore, we present and evaluate a method for introducing parallelism into the multiple non-overlapping camera pose estimation algorithm proposed in [1]. In this algorithm the problem has been solved in real time using multiple non-overlapping cameras and the Extended Kalman Filter (EKF). Four cameras arranged in two back-to-back pairs are put on the platform of a moving robot. An important benefit of using multiple cameras for robot pose estimation is the capability of resolving vision uncertainties such as the bas-relief ambiguity. The proposed method is based on algorithmic skeletons for low, medium and high levels of parallelization. The analysis shows that the use of a multiprocessor system enhances the system performance by about 87%. In addition, the proposed design is scalable, which is necaccery in this application where the number of features changes repeatedly.

6LoWPAN 단편화 패킷 재전송에 따른 암호화 알고리즘 성능 분석 (Performance Evaluation of Cryptographic Algorithms for the 6LoWPAN with Packet Fragmentations)

  • 김현곤
    • 한국컴퓨터정보학회논문지
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    • 제16권8호
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    • pp.77-84
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    • 2011
  • 본 논문에서는 무선 구간에서 패킷 손실을 최소화 할 수 있는 재전송 기법과 기밀성 제공을 위해 암복호화 알고리즘을 적용한 6LoWPAN 프로토콜을 MICAz 센서에 구현하고 실험적인 성능을 분석하였다. 재전송 기법에서는 재생공격을 방지하기 위한 단편화 패킷 순서번호, 타임 스템프, 난스, 체크섬을 구현하였으며, 패킷 기밀성과 무결성을 제공하기 위해 AES, 3DES, SHA2, SHA1 알고리즘을 구현하였다. 실험 결과에 의하면 전송에러가 높아질수록 즉, 패킷 손실이 높아질수록 재전송이 급격하게 증가하고, 홉 수가 증가함에 따라 재전송이 비례적으로 증가함을 알 수 있었다. 그리고 암복호화 수행 시간이 재전송 처리 시간보다 상대적으로 크다는 것을 알 수 있었다.