Yes / Human activity recognition from sensor readings have proved to be an effective approach in pervasive computing for smart healthcare. Recent approaches to ambient assisted living (AAL) within a home or community setting offers people the prospect of more individually-focused care and improved quality of living. However, most of the available AAL systems are often limited by computational cost. In this paper, a simple, novel non-wearable human activity classification framework using the multivariate Gaussian is proposed. The classification framework augments prior information from the passive RFID tags to obtain more detailed activity profiling. The proposed algorithm based on multivariate Gaussian via maximum likelihood estimation is used to learn the features of the human activity model. Twelve sequential and concurrent experimental evaluations are conducted in a mock apartment environment. The sampled activities are predicted using a new dataset of the same activity and high prediction accuracy is established. The proposed framework suits well for the single and multi-dwelling environment and offers pervasive sensing environment for both patients and carers. / Tertiary Education Trust Fund of Federal Government of Nigeria and by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement H2020-MSCA-ITN-2016 SECRET-722424

Fitness tracking is a rapidly growing market as more people desire to take better control over their lives. And the growing availability of smartphones with sensitive sensors makes it possible for anyone to take part. This project aims to implement a Step Counter and create a model for Human Activity Recognition (HAR) to classify activities such as walking, running, cycling, ascending and descending stairs, and standing still, using sensor data from handheld devices. The Step Counter is implemented by processing acceleration data and finding and validating steps. HAR is implemented using three machine learning algorithms on processed sensor data: Random Forest (RF), Support Vector Machine (SVM), and Artificial Neural Network (ANN). The step counter achieved 99.48% accuracy. The HAR models achieved 99.7%, 99.6%, and 99.5% accuracy on RF, ANN, and SVM, respectively. / Aktivitetsspårning är en snabbt växande marknad när fler människor önskar att ta bättre kontroll över deras liv. Den växande tillgängligheten på smartphones med känsliga sensorer gör det möjligt för vem som helst att delta. Detta projekt siktar på att implementera en stegräknare samt skapa en modell för mänsklig aktivitetsigenkänning (HAR) för att klassificera aktiviteter såsom att promenera, springa, cykla, gå upp eller ner för trappor och stå stilla, med användning av sensordata från handhållna enheter. Stegräknaren implementeras genom att bearbeta accelerationsdata och hitta samt validera steg. HAR implementeras med hjälp av tre maskininlärningsalgoritmer på bearbetad sensordata: Random Forest (RF), Support Vector Machine (SVM) och Artificial Neural Network (ANN). Stegräknaren uppnådde en noggrannhet på 99.48%. HAR-modellerna uppnådde en noggrannhet på 99.7%, 99.6% samt 99.5% med RF, ANN och SVM. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

In this thesis we present a system for detection of events in video. First a multiview approach to automatically detect and track heads and hands in a scene is described. Then, by making use of epipolar, spatial, trajectory, and appearance constraints, objects are labeled consistently across cameras (zooms). Finally, we demonstrate a new machine learning paradigm, TemporalBoost, that can recognize events in video. One aspect of any machine learning algorithm is in the feature set used. The approach taken here is to build a large set of activity features, though TemporalBoost itself is able to work with any feature set other boosting algorithms use. We also show how multiple levels of zoom can cooperate to solve problems related to activity recognition.

Human activity recognition based on wearable sensors’ data is quite an attractive subject due to its wide application in the fields of healthcare, wellbeing and smart environments. This research is also focussed on predictive performance comparison of machine learning algorithms for activity recognition from wearable sensors’ (MHEALTH) data while employing a comprehensive process. The framework is adapted from well-laid data science practices which addressed the data analyses requirements quite successfully. Moreover, an Analysis Tool is also developed to support this work and to make it repeatable for further work. A detailed comparative analysis is presented for five multi-class classifier algorithms on MHEALTH dataset namely, Linear Discriminant Analysis (LDA), Classification and Regression Trees (CART), Support Vector Machines (SVM), K-Nearest Neighbours (KNN) and Random Forests (RF). Beside using original MHEALTH data as input, reduced dimensionality subsets and reduced features subsets were also analysed. The comparison is made on overall accuracies, class-wise sensitivity and specificity of each algorithm, class-wise detection rate and detection prevalence in comparison to prevalence of each class, positive and negative predictive values etc. The resultant statistics have also been compared through visualizations for ease of understanding and inference. All five ML algorithms were applied for classification using the three sets of input data. Out of all five, three performed exceptionally well (SVM, KNN, RF) where RF was best with an overall accuracy of 99.9%. Although CART did not perform well as a classification algorithm, however, using it for ranking inputs was a better way of feature selection. The significant sensors using CART ranking were found to be accelerometers and gyroscopes; also confirmed through application of predictive ML algorithms. In dimensionality reduction, the subset data based on CART-selected features yielded better classification than the subset obtained from PCA technique.

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Human activity recognition (HAR) is a growing area within machine learning as the possible applications are vast, especially with the growing amount of collectable sensor data as Internet of Things-devices are becoming more accessible. This project aims to contribute to HAR by developing two supervised machine learning algorithms that are able to distinguish between four different human activities. We collected data from the tri-axial accelerometer in two different smartphones while doing these activities, and put together a dataset. The algorithms that were used was a convolutional neural network (CNN) and a support vector machine (SVM), and they were applied to the dataset separately. The results show that it is possible to accurately classify the activities using the algorithms and that a short time window of 3 seconds is enough to classify the activities with an accuracy of over 99% with both algorithms. The SVM outperformed the CNN slightly. We also discuss the result and continuations of this study. / Mlinsklig aktivitetsigenkanning (HAR) lir ett vlixande omrade inom maskininllirning da de mojliga applikationerna lir stora, speciellt med den vlixande mangd insamlingsbar sensordata da Internet of Things-enheter blir mer atkomliga. Detta projekt siktar pa att bidra till HAR genom att utveckla tva algoritmer som kan urskilja mellan fyra olika mlinskliga aktiviteter. Vi samlade in data fran den treaxlade accelerometern i tva olika smarta telefoner medans dessa aktiviteter utfordes, och satte ihop ett dataset. Algoritmerna som anvlindes var ett faltande neuralt nlitverk och en stodvektormaskin, och de applicerades separat pa datasetet. Resultaten visar att det lir mojligt att med slikerhet klassificera aktiviteterna genom att anvlinda dessa algoritmer och att ett kort tidsfonster med 3 sekunder av data lir tillrlickligt for att klassificera med en slikerhet pa over 99% med bada algoritmerna. Stodvektormaskinen presterade nagot blittre an det neurala nlitverket. Vi diskuterar liven resultatet och fortsatta studier. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

Internet of Things devices, such as smartphonesand smartwatches, are currently becoming widely accessible andprogressively advanced. As the use of these devices steadilyincreases, so does the access to large amounts of sensory data.In this project, we developed a system that recognizes certainactivities by applying a linear classifier machine learning modelto a data set consisting of examples extracted from accelerometersensor data. We obtained the data set by collecting data from amobile device while performing commonplace everyday activities.These activities include walking, standing, driving, and ridingthe subway. The raw accelerometer data was then aggregatedinto data points, consisting of several informative features. Thecomplete data set was subsequently split into 80% training dataand 20% test data. A machine learning algorithm, in this case,a support vector machine, was presented with the training dataset and finally classified all test data with a precision higher than90%. Hence, meeting our set objective to build a service with acorrect classification score of over 90%.Human activity recognition has a large area of application,including improved health-related recommendations and a moreefficiently engineered system for public transportation. / Internet of Things-enheter, så som smarta telefoner och klockor, blir numera allt mer tillgängliga och tekniskt avancerade. Eftersom användningen av dessa smarta enheter stadigt ökar, ökar också tillgången till stora mängder data från sensorer i dessa enheter. I detta projekt utvecklade vi ett system som känner igen vissa aktiviteter genom att tillämpa en linjär klassificerande maskininlärningsmodell på en uppsättning data som extraherats från en accelerometer, en sensor i en smart telefon. Datauppsättningen skapades genom att samla in data från en smart telefon medan vi utförde vardagliga aktiviteter, så som promenader, stå stilla, köra bil och åka tunnelbana. Rå accelerometerdata samlades in och gjordes om till datavektorer innehållandes statistiska mått. Den totala datauppsättningen delades sedan upp i 80% träningsdata och 20% testdata. En maskininlärningsalgoritm, i detta fall en supportvektormaskin, introducerades med träningsdatan och klassificerade slutligen testdatan med en precision på över 90%. Därmed uppfylldes vårt uppsatta mål med att bygga en tjänst med en korrekt klassificering på över 90%. Igenkänning av mänsklig aktivitet har ett stort användningsområde, och kan bidra till förbättrade hälsorekommendationer och en mer effektiv kollektivtrafik. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

With an increase in age comes an increase in the risk of frailty and mobility decline, which can lead to dangerous falls and can even be a cause of mortality. Despite these serious consequences, healthcare systems remain reactive, highlighting the need for technologies to predict functional mobility decline. In this thesis, we present an end-to-end autonomous functional mobility assessment system that seeks to bridge the gap between robotics research and clinical rehabilitation practices. Unlike many fully integrated black-box models, our approach emphasizes the need for a system that is both reliable as well as transparent to facilitate its endorsement and adoption by healthcare professionals and patients. Our proposed system is characterized by the sensor fusion of multimodal data using an optimization framework known as factor graphs. This method, widely used in robotics, enables us to obtain visually interpretable 3-D estimations of the human body in recorded footage. These representations are then used to implement autonomous versions of standardized assessments employed by physical therapists for measuring lower-limb mobility, using a combination of custom neural networks and explainable models. To improve the accuracy of the estimations, we investigate the application of the Koopman operator framework to learn linear representations of human dynamics: We leverage these outputs as prior information to enhance the temporal consistency across entire movement sequences. Furthermore, inspired by the inherent stability of natural human movement, we propose ways to impose stability constraints in the dynamics during the training of linear Koopman models. In this light, we propose a sufficient condition for the stability of discrete-time linear systems that can be represented as a set of convex constraints. Additionally, we demonstrate how it can be seamlessly integrated into larger-scale gradient descent optimization methods. Lastly, we report the performance of our human pose detection and autonomous mobility assessment systems by evaluating them on outcome mobility datasets collected from controlled laboratory settings and unconstrained real-life home environments. While we acknowledge that further research is still needed, the study results indicate that the system can demonstrate promising performance in assessing mobility in home environments. These findings underscore the significant potential of this and similar technologies to revolutionize physical therapy practices.

Human Activity Recognition (HAR) field studies the application of artificial intelligence methods for the identification of activities performed by people. Many applications of HAR in healthcare and sports require the safety-critical performance of the predictive models. The predictions produced by these models should be not only correct but also trustworthy. However, in recent years it has been shown that modern neural networks tend to produce sometimes wrong and overconfident predictions when processing unusual inputs. This issue puts at risk the prediction credibility and calls for solutions that might help estimate the uncertainty of the model’s predictions. In the following work, we started the investigation of the applicability of Non-Bayesian Uncertainty Estimation methods to the Deep Learning classification models in the HAR. We trained a Convolutional Neural Network (CNN) model with public datasets, such as UCI HAR and WISDM, which collect sensor-based time-series data about activities of daily life. Through a series of four experiments, we evaluated the performance of two Non-Bayesian uncertainty estimation methods, ODIN and Deep Ensemble, on out-of-distribution detection. We found out that the ODIN method is able to separate out-of-distribution samples from the in-distribution data. However, we also obtained unexpected behavior, when the out-of-distribution data contained exclusively dynamic activities. The Deep Ensemble method did not provide satisfactory results for our research question. / Inom området Human Activity Recognition (HAR) studeras tillämpningen av metoder för artificiell intelligens för identifiering av aktiviteter som utförs av människor. Många av tillämpningarna av HAR inom hälso och sjukvård och idrott kräver att de prediktiva modellerna har en säkerhetskritisk prestanda. De förutsägelser som dessa modeller ger upphov till ska inte bara vara korrekta utan också trovärdiga. Under de senaste åren har det dock visat sig att moderna neurala nätverk tenderar att ibland ge felaktiga och överdrivet säkra förutsägelser när de behandlar ovanliga indata. Detta problem äventyrar förutsägelsernas trovärdighet och kräver lösningar som kan hjälpa till att uppskatta osäkerheten i modellens förutsägelser. I följande arbete inledde vi undersökningen av tillämpligheten av icke-Bayesianska metoder för uppskattning av osäkerheten på Deep Learning-klassificeringsmodellerna i HAR. Vi tränade en CNN-modell med offentliga dataset, såsom UCI HAR och WISDM, som samlar in sensorbaserade tidsseriedata om aktiviteter i det dagliga livet. Genom en serie av fyra experiment utvärderade vi prestandan hos två icke-Bayesianska metoder för osäkerhetsuppskattning, ODIN och Deep Ensemble, för upptäckt av out-of-distribution. Vi upptäckte att ODIN-metoden kan skilja utdelade prover från data som är i distribution. Vi fick dock också ett oväntat beteende när uppgifterna om out-of-fdistribution uteslutande innehöll dynamiska aktiviteter. Deep Ensemble-metoden gav inga tillfredsställande resultat för vår forskningsfråga.