A Classification System for Diabetic Patients with Machine Learning Techniques

International audienceDiabetes mellitus (DM) is a group of metallic disorder characterized by steep levels of blood glucose prolonged over a time. It results the defection in insulin production or improper action of the cells to the insulin produced. It is one of the significant public health care challenge worldwide. Diabetes exists in a body when pancreas does not construct enough hormone insulin or the human body is not being able to use the insulin properly. The diagnosis of diabetes (diagnosis, etiopathophysiology, therapy etc.) need to generate and process the vast amount of data. Data mining techniques have proven its usefulness and effectiveness in order to evaluate the unknown relationships or patterns if exists with such vast data. In the present work, five techniques based on machine learning namely, AdaBoost, LogicBoost, RobustBoost, Naïve Bayes and Bagging have been proposed for the analysis and prediction of DM patients. The proposed techniques are employed on the data set of Pima Indians Diabetes patients. The results computed are found to be very accurate with classification accuracy of 81.77% and 79.69% by bagging and AdaBoost techniques, respectively. Hence, the proposed techniques employed here are highly adorable, effective and efficient in order to predict the DM

Clinical evaluation of a novel adaptive bolus calculator and safety system in Type 1 diabetes

Bolus calculators are considered state-of-the-art for insulin dosing decision support for people with Type 1 diabetes (T1D). However, they all lack the ability to automatically adapt in real-time to respond to an individual’s needs or changes in insulin sensitivity. A novel insulin recommender system based on artificial intelligence has been developed to provide personalised bolus advice, namely the Patient Empowerment through Predictive Personalised Decision Support (PEPPER) system. Besides adaptive bolus advice, the decision support system is coupled with a safety system which includes alarms, predictive glucose alerts, predictive low glucose suspend for insulin pump users, personalised carbohydrate recommendations and dynamic bolus insulin constraint. This thesis outlines the clinical evaluation of the PEPPER system in adults with T1D on multiple daily injections (MDI) and insulin pump therapy. The hypothesis was that the PEPPER system is safe, feasible and effective for use in people with TID using MDI or pump therapy. Safety and feasibility of the safety system was initially evaluated in the first phase, with the second phase evaluating feasibility of the complete system (safety system and adaptive bolus advisor). Finally, the whole system was clinically evaluated in a randomised crossover trial with 58 participants. No significant differences were observed for percentage times in range between the PEPPER and Control groups. For quality of life, participants reported higher perceived hypoglycaemia with the PEPPER system despite no objective difference in time spent in hypoglycaemia. Overall, the studies demonstrated that the PEPPER system is safe and feasible for use when compared to conventional therapy (continuous glucose monitoring and standard bolus calculator). Further studies are required to confirm overall effectiveness.Open Acces

Complex event recognition through wearable sensors

Complex events are instrumental in understanding advanced behaviours and properties of a system. They can represent more meaningful events as compared to simple events. In this thesis we propose to use wearable sensor signals to detect complex events. These signals are pertaining to the user's state and therefore allow us to understand advanced characteristics about her. We propose a hierarchical approach to detect simple events from the wearable sensors data and then build complex events on top of them. In order to address privacy concerns that rise from the use of sensitive signals, we propose to perform all the computation on device. While this ensures the privacy of the data, it poses the problem of having limited computational resources. This problem is tackled by introducing energy efficient approaches based on incremental algorithms. A second challenge is the multiple levels of noise in the process. A first level of noise concerns the raw signals that are inherently imprecise (e.g. inaccuracy in GPS readings). A second level of noise, that we call semantic noise, is present among the simple events detected. Some of these simple events can disturb the detection of complex events effectively acting as noise. We apply the hierarchical approach in two different contexts defining the two different parts of our thesis. In the first part, we present a mobile system that builds a representation of the user's life. This system is based on the episodic memory model, which is responsible for the storage and recollection of past experiences. Following the hierarchical approach, the system processes raw signals to detect simple events such as places where the user stayed a certain amount of time to perform an activity, therefore building sequences of detected activities. These activities are in turn processed to detect complex events that we call routines and that represent recurrent patterns in the life of the user. In the second part of this thesis, we focus on the detection of glycemic events for diabetes type-1 patients in a non-invasive manner. Diabetics are not able to properly regulate their glucose, leading to periods of high and low blood sugar. We leverage signals (Electrocardiogram (ECG), accelerometer, breathing rate) from a sport belt to infer such glycemic events. We propose a physiological model based on the variations of the ECG when the patient has low blood sugar, and an energy-based model that computes the current glucose level of the user based on her glucose intake, insulin intake and glucose consumption via physical activity. For both contexts, we evaluate our systems in term of accuracy by assessing wether the detected routines are meaningful, and wether the glycemic events are correctly detected, and in term of mobile performance, which confirms the fitness of our approaches for mobile computation

Modelo adaptativo baseado em sensor virtual para eletromiografia de superfície com sistema de classificação tolerante a falhas

Apenas alguns sistemas de controle protético na literatura científica são baseados em algoritmos de reconhecimento de padrões, os quais são adaptados às mudanças que ocorrem no sinal mioelétrico ao longo do tempo, e, frequentemente, tais sistemas não são naturais e intuitivos. As mudanças no sinal mioelétrico são alguns dos vários desafios para as próteses mioelétricas serem amplamente utilizadas. O conceito do sensor virtual, que tem como objetivo fundamental estimar medidas indisponíveis por trás de outras medidas disponíveis, vem sendo utilizado em outras áreas de pesquisa. O sensor virtual aplicado à eletromiografia de superfície (sEMG) pode ajudar a minimizar esses problemas, tipicamente relacionados à degradação do sinal mioelétrico, os quais geralmente provocam uma diminuição na taxa de acerto da classificação dos movimentos por sistemas de inteligência computacional. A principal contribuição deste trabalho é o desenvolvimento de um sistema de classificação de movimentos tolerante a falhas, o qual utiliza o conceito de sensores virtuais para reduzir o impacto de degradação de sinais de sEMG. A segunda contribuição é um modelo do sinal de sEMG dinâmico e adaptativo para o sensor virtual, o qual produz um modelo de saída de sinal independente da aquisição física do sinal de interesse. A modelagem do sinal de sEMG é projetada de forma a combinar os conceitos de multicanais e sua correlação cruzada, além de utilizar um sistema de ajuste dos coeficientes de correlação, a fim de substituir os canais de sinais degradados Dois modelos são avaliados e detalhados: Time-Varying Autoregressive Moving Average (TVARMA) e o Time- Varying Kalman Filter (TVK). A terceira contribuição é a combinação de uma análise e detecção da contaminação do sinal realizada por um sensor de detecção tolerante a falhas (Sensor Fault-Tolerant Detector – SFTD). Os resultados da classificação dos movimentos foram apresentados comparando as técnicas usuais de classificação com o método da substituição do sinal degradado e um processo de retreinamento do classificador simplificado. Os resultados foram avaliados para cinco tipos de ruído em 16 estudos de caso da degradação dos canais de sEMG. O sistema adaptativo proposto sem o uso de técnicas de retreinamento do classificador recuperou a taxa de acerto média de classificação em até 46% para os ruídos de deslocamento de eletrodos e de saturação. Devido às limitações do sistema proposto quanto aos ruídos de artefato de movimento, de interferência de linha de energia e ECG, o sistema apresentado pode ser utilizado como uma técnica complementar com outras técnicas de classificação para aumentar o impacto clínico da prótese mioelétrica. Entretanto, o sistema ainda requer uma análise quanto a diferentes níveis de SNR antes de uma otimização do algoritmo. Além disso, o modelo TVARMA do sensor virtual obteve uma taxa de acerto média superior em comparação ao modelo TVK na maioria das situações avaliadas neste trabalho.Nowadays, only a few prosthetic control systems in the scientific literature are founded on pattern recognition algorithms adapted to changes that occur in the myoelectric signal over time and, frequently, such systems are not natural and intuitive. These are some of the several challenges for myoelectric prostheses for everyday use. The concept of the virtual sensor, which has as its fundamental objective to estimate unavailable measures based on other available measures, is already being used in other fields of research. The virtual sensor technique applied to surface electromyography (sEMG) can help to mitigate these problems, typically related to the degradation of the myoelectric signal that usually leads to a decrease in the classification accuracy of the movements characterized by intelligent computational systems. Therefore, the main contribution of this work is the Fault-Tolerant Classification System, that was developed using the concept of virtual sensors to reduce the degradation impact of sEMG signals. The second contribution is a dynamic and adaptive virtual sensor model, which produces a signal output model independent of the physical acquisition of the interest signal. The sEMG signal modeling was designed to combine multichannel concepts and their cross-correlation, in addition to the use of the correlation coefficient adjustment system to replace degraded signal channels. Two models were evaluated and detailed: Time-Varying Autoregressive Moving Average (TVARMA) and Time-Varying Kalman Filter (TVK) The third contribution is the analysis and detection of signal contamination by a Sensor Fault-Tolerant Detector (SFTD). The classification results of the movements were compared to the traditional classification techniques, the classification with the degraded signal replacement method and a simplified retraining process of the classifier. The results were evaluated for five noise types in 16 case studies of the sEMG channels degradation. The adaptive system proposed, without the classifier re-training techniques, was able to recover 46% of the mean classification accuracy for the electrodes displacement and saturation noise. Moreover, the proposed system can be used as a complementary technique with other classification techniques to increase the clinical impact of the myoelectric prosthesis since there are still limitations in the proposed method regarding the movement artifact noise, power line, and ECG interference. However, the system still requires an analysis of different SNR levels before the algorithm optimization. Also, the TVARMA model of the virtual sensor obtained a higher classification accuracy compared to the TVK model in most of the evaluated situations

Adaptive basal insulin recommender system based on Kalman filter for type 1 diabetes

Type 1 diabetes mellitus is a chronic disease that requires those affected to self-administer insulin to control their blood glucose level. However, the estimation of the correct insulin dosage is not easy due to the complexity of glucose metabolism, which usually leads to blood glucose levels far from the optimal. This paper presents an adaptive and personalised basal insulin recommender system based on Kalman filter theory that can be used with or without continuous glucose monitoring systems. The proposed approach is tested with the UVa/PADOVA simulator with eleven virtual adult subjects. It has been tested in combination with two different bolus calculators, and the performance achieved has been compared with that obtained with the default basal doses of the simulator, which can be assumed as optimal. The achieved results demonstrate that the proposed system rapidly converges to the optimal basal dose, and it can be used with adaptive bolus calculators without the risk of instabilityThis project has received funding from the grant of the University of Girona 2016-2018 (MPCUdG2016) and the European Union Horizon 2020 research and innovation programme under grant agreement No. 689810, www.pepper.eu.com/, PEPPE