1,310 research outputs found

    Intelligent Anomaly Detection of Machine Tools based on Mean Shift Clustering

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    For a fault detection of machine tools, fixed intervention thresholds are usually necessary. In order to provide an autonomous anomaly detection without the need for fixed limits, recurring patterns must be detected in the signal data. This paper presents an approach for online pattern recognition on NC Code based on mean shift clustering that will be matched with drive signals. The intelligent fault detection system learns individual intervention thresholds based on the prevailing machining patterns. Using a self-organizing map, data captured during the machine’s operation are assigned to a normal or malfunction state

    Data-driven microscopy: placing high-fidelity data in a population-wide context

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    Mikroskopi Àr idag ett fundamentalt verktyg inom forskning, dÀr det tillÄter oss att skÄda in och utforska vÄra prover i hög detalj. Mycket utav utvecklingen av nya mikroskopimetoder har strÀvat efter att öka den detaljnivÄ vi kan uppnÄ. Samtidigt har utvecklingen inom hÄrdvara, med tillgÄng till bÀttre och mer kraftfulla instrument, lett till utveckligen av metoder dÀr fokuset Àr att studera en hel population av celler. Till skillnad frÄn nÀr vi studerar ett fÄtal celler i hög detalj, tillÄter det oss att sÀtta perspektiv pÄ det vi ser. Det ger oss en förmÄga att sÀga vad det normala beteendet som man kan förvÀnta sig Àr, och vilka celler som sticker ut i en population. Med andra ord, vad som Àr intressant.Samtidigt finns det ett stort intresse av att veta hur varje individuell cell beter sig. Varje cell Àr, precis som oss mÀnniskor, unik. De har olika historia, olika Älder och befinner sig i olika tillstÄnd. Precis som vÄra celler i kroppen Àr unika, Àr Àven de cellerna som kan orsaka sjukdom unika. För att förstÄ varför vissa personer Àr mer kÀnsliga mot sjukdom, och hur en infektion svarar pÄ vÄra behandlingar behövs en förstÄelse och an förmÄga att studera celler pÄ individuell nivÄ, samtidigt som vi bibehÄller ett perspektiv utifrÄn populations-nivÄ.Denna brist pÄ perspektiv har lÀnge varit ett problem inom mikroskopi. Den vanliga lösningen pÄ detta problem Àr att vi, som mÀnniskor, kan tolka en bild och peka pÄ vad det Àr som Àr intressant eller inte. Vi Àr, trots allt, extremt duktiga pÄ att tolka visuell information. Men detta Àr inte en helt felfri lösning. Som mÀnniskor kan vi vara relativt okonsekventa, vi tolkar oftast utifrÄn hur vi vill att datan ser ut. Med andra ord, vi saknar förmÄgan att vara objektiva i vÄr metodik för att samla in bilder i hög detalj.Min avhandling har till stor del handlat om att utveckla ett verktyg som tillÄter oss att sÀtta perspektiv pÄ det vi studerar med mikroskopi. Detta har lett till Arbete 1, dÀr vi presenterar en allmÀn strategi (data-styrd mikroskopi) för hur vi kan arbeta med mikroskopi för att samla in data pÄ en hel population, samtidigt som vi kan samla in data med hög detalj pÄ relevanta fynd i populationen. Vi presenterar Àven hÀr en teknisk lösning, och utför metoden i tre olika scenarion: ett för att studera en population av celler mer allmÀnt, ett för att fÄnga det ögonblick som bakterier infekterar mÀnskliga celler, och ett dÀr vi studerar och fÄngar in data pÄ relevanta (frÄn ett populations-kontext) cancerceller och följer dem över tid. Denna metod tillÄter oss att samla in data i hög detalj pÄ ett objektivt sÀtt, och att sÀtta perspektiv pÄ det vi studerar.I Arbete 2 har vi vidare utvecklat pÄ vÄr metod, dÀr vi försöker lösa problemet att hitta en och samma cell i flera olika mikroskop. Eftersom vi, genom mikroskopi, jobbar pÄ en sÄ ofantligt liten skala, Àr det oftast vÀldigt svÄrt att orientera sig och hitta rÀtt inom ett prov. Det Àr lite som att spela PÄ spÄret och gissa vart man Àr, fast utan alla ledtrÄdar man fÄr pÄ varje nivÄ. Eftersom vi har tillgÄng till data pÄ en hel population, sÄ utgick vi frÄn att det borde finnas samband mellan celler och deras grannar i ett prov som Àr unika för just dem. Genom att anvÀnda sig av dessa unika samband kom vi fram med en lösning dÀr vi snabbt kan kalibrera ett prov pÄ ett nytt mikroskop. Det öppnar dörrarna för oss forskare att ÄteranvÀnda prov, att lÀttare justera provet med nya markörer (för det vi vill visualisera inom cellerna), och att kunna tolka ett prov med data insamlat frÄn flera system.COVID-19 pandemin var en stor omstÀllning för samhÀllet och vÄrden. LikvÀl var det en stor omstÀllning för mÄnga forskningslabb, dÀr en kapplöpning startade för att sÄ snabbt som möjligt förstÄ sig pÄ hur viruset fungerar och hur vÄrt immunförsvar svarar pÄ dess infektion. Det var i detta kontext som mitt tredje arbete utfördes. Genom den erfarenhet jag samlat pÄ mig inom mikroskopi och att analysera bilder pÄ stora dataset, bidrog jag med hjÀlp för att studera hur framtagna antikroppar kan förhindra bindningen av virus-lika partiklar till celler. Antikroppar Àr ett protein som immunförsvaret producerar i respons mot en patogen. En bÀttre förstÄelse kring hur antikroppar verkar, och vad skillnaden mellan en bra och en dÄlig antikropp Àr kan leda till framtagningen av bÀttre vaccin-program och behandlingar inom sjukvÄrden.I Arbete 4 medverkade jag i ett arbete dÀr bakterien Streptococcus pyogenes var i fokus. S. pyogenes enda vÀrd Àr mÀnniskor, och ansvarar för över 600 miljoner infektionsfall per Är globalt. PÄ bakteriens yta dominerar ett protein, M-proteinet, ett multi-funktionellt protein som bakterien (bland annat) anvÀnder sig för att binda till ytor och förhindra immunförsvarets förmÄga att göra sig av med bakterien. I arbetet upptÀckte vi att fibronektin binder till bakterien (specifikt M-proteinet) olika mycket beroende pÄ mÀngden antikroppar som finns i miljön. Fibronektin Àr ett protein som vi mÀnniskor producerar, och bidrar (bland annat) till att skapa den miljön som celler befinner sig i. MÀngden fibronektin varierar beroende pÄ var i kroppen man kollar. Till exempel, i saliv har du en relativt lÄg mÀngd fibronektin jÀmfört med i blodet. Detta ledde till hypotesen att bakterien Àr special-anpassad för olika miljöer i dess förmÄga att undkomma immunförsvaret. En bÀttre förstÄelse kring hur bakterien Àr anpassad till vÄra olika miljöer och dess infektionsförlopp kan leda till bÀttre och mer anpassade behandlingar inom sjukvÄrden

    A Survey of Knowledge Representation in Service Robotics

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    Within the realm of service robotics, researchers have placed a great amount of effort into learning, understanding, and representing motions as manipulations for task execution by robots. The task of robot learning and problem-solving is very broad, as it integrates a variety of tasks such as object detection, activity recognition, task/motion planning, localization, knowledge representation and retrieval, and the intertwining of perception/vision and machine learning techniques. In this paper, we solely focus on knowledge representations and notably how knowledge is typically gathered, represented, and reproduced to solve problems as done by researchers in the past decades. In accordance with the definition of knowledge representations, we discuss the key distinction between such representations and useful learning models that have extensively been introduced and studied in recent years, such as machine learning, deep learning, probabilistic modelling, and semantic graphical structures. Along with an overview of such tools, we discuss the problems which have existed in robot learning and how they have been built and used as solutions, technologies or developments (if any) which have contributed to solving them. Finally, we discuss key principles that should be considered when designing an effective knowledge representation.Comment: Accepted for RAS Special Issue on Semantic Policy and Action Representations for Autonomous Robots - 22 Page

    A NOVEL APPROACH FOR DETECTION FAULT IN THE AIRCRAFT EXTERIOR BODY USING IMAGE PROCESSING

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    The primary objective of this thesis is to develop innovative techniques for the inspection and maintenance of aircraft structures. We aim to streamline the entire process by utilizing images to detect potential defects in the aircraft body and comparing them to properly functioning images of the aircraft. This enables us to determine whether a specific section of the aircraft is faulty or not. We achieve this by employing image processing to train a model capable of identifying faulty images. The image processing methodology we use involves the use of images of both defective and operational parts of the aircraft\u27s exterior. These images undergo a preprocessing phase that preserves valuable details. During the training period, a new image of the same section of the aircraft is used to validate the model. After processing, the algorithm grades the image as faulty or normal. To facilitate our study, we rely on the Convolutional Neural Network (CNN) approach. This technique collects distinguishing features from a single patch created by the frame segmentation of a CNN kernel. Furthermore, we use various filters to process the images using the image processing toolbox available in Python. In our initial trials, we observed that the CNN model struggled with the overfitting of the faulty class. To address this, we applied image augmentation by converting a small dataset of 87 images to an augmented dataset of 4000 images. After passing the data through multiple convolutional layers and executing multiple epochs, our proposed model achieved an impressive training accuracy of 98.28%. In addition, we designed a GUI-based interface that allows users to input an image and view the results in terms of faulty or normal. Finally, we propose that the application of this research in the field of robotics would be an ideal area for future work

    Segmentation of images by color features: a survey

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    En este articulo se hace la revisiĂłn del estado del arte sobre la segmentaciĂłn de imagenes de colorImage segmentation is an important stage for object recognition. Many methods have been proposed in the last few years for grayscale and color images. In this paper, we present a deep review of the state of the art on color image segmentation methods; through this paper, we explain the techniques based on edge detection, thresholding, histogram-thresholding, region, feature clustering and neural networks. Because color spaces play a key role in the methods reviewed, we also explain in detail the most commonly color spaces to represent and process colors. In addition, we present some important applications that use the methods of image segmentation reviewed. Finally, a set of metrics frequently used to evaluate quantitatively the segmented images is shown

    Symbol Emergence in Robotics: A Survey

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    Humans can learn the use of language through physical interaction with their environment and semiotic communication with other people. It is very important to obtain a computational understanding of how humans can form a symbol system and obtain semiotic skills through their autonomous mental development. Recently, many studies have been conducted on the construction of robotic systems and machine-learning methods that can learn the use of language through embodied multimodal interaction with their environment and other systems. Understanding human social interactions and developing a robot that can smoothly communicate with human users in the long term, requires an understanding of the dynamics of symbol systems and is crucially important. The embodied cognition and social interaction of participants gradually change a symbol system in a constructive manner. In this paper, we introduce a field of research called symbol emergence in robotics (SER). SER is a constructive approach towards an emergent symbol system. The emergent symbol system is socially self-organized through both semiotic communications and physical interactions with autonomous cognitive developmental agents, i.e., humans and developmental robots. Specifically, we describe some state-of-art research topics concerning SER, e.g., multimodal categorization, word discovery, and a double articulation analysis, that enable a robot to obtain words and their embodied meanings from raw sensory--motor information, including visual information, haptic information, auditory information, and acoustic speech signals, in a totally unsupervised manner. Finally, we suggest future directions of research in SER.Comment: submitted to Advanced Robotic

    Convolutional Neural Networks accurately predict cover fractions of plant species and communities in Unmanned Aerial Vehicle imagery

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    Unmanned Aerial Vehicles (UAV) greatly extended our possibilities to acquire high resolution remote sensing data for assessing the spatial distribution of species composition and vegetation characteristics. Yet, current pixel‐ or texture‐based mapping approaches do not fully exploit the information content provided by the high spatial resolution. Here, to fully harness this spatial detail, we apply deep learning techniques, that is, Convolutional Neural Networks (CNNs), on regular tiles of UAV‐orthoimagery (here 2–5 m) to identify the cover of target plant species and plant communities. The approach was tested with UAV‐based orthomosaics and photogrammetric 3D information in three case studies, that is, (1) mapping tree species cover in primary forests, (2) mapping plant invasions by woody species into forests and open land and (3) mapping vegetation succession in a glacier foreland. All three case studies resulted in high predictive accuracies. The accuracy increased with increasing tile size (2–5 m) reflecting the increased spatial context captured by a tile. The inclusion of 3D information derived from the photogrammetric workflow did not significantly improve the models. We conclude that CNN are powerful in harnessing high resolution data acquired from UAV to map vegetation patterns. The study was based on low cost red, green, blue (RGB) sensors making the method accessible to a wide range of users. Combining UAV and CNN will provide tremendous opportunities for ecological applications

    Sustainable Agriculture and Advances of Remote Sensing (Volume 2)

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    Agriculture, as the main source of alimentation and the most important economic activity globally, is being affected by the impacts of climate change. To maintain and increase our global food system production, to reduce biodiversity loss and preserve our natural ecosystem, new practices and technologies are required. This book focuses on the latest advances in remote sensing technology and agricultural engineering leading to the sustainable agriculture practices. Earth observation data, in situ and proxy-remote sensing data are the main source of information for monitoring and analyzing agriculture activities. Particular attention is given to earth observation satellites and the Internet of Things for data collection, to multispectral and hyperspectral data analysis using machine learning and deep learning, to WebGIS and the Internet of Things for sharing and publication of the results, among others
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