Modeling Individual Cyclic Variation in Human Behavior

Cycles are fundamental to human health and behavior. However, modeling cycles in time series data is challenging because in most cases the cycles are not labeled or directly observed and need to be inferred from multidimensional measurements taken over time. Here, we present CyHMMs, a cyclic hidden Markov model method for detecting and modeling cycles in a collection of multidimensional heterogeneous time series data. In contrast to previous cycle modeling methods, CyHMMs deal with a number of challenges encountered in modeling real-world cycles: they can model multivariate data with discrete and continuous dimensions; they explicitly model and are robust to missing data; and they can share information across individuals to model variation both within and between individual time series. Experiments on synthetic and real-world health-tracking data demonstrate that CyHMMs infer cycle lengths more accurately than existing methods, with 58% lower error on simulated data and 63% lower error on real-world data compared to the best-performing baseline. CyHMMs can also perform functions which baselines cannot: they can model the progression of individual features/symptoms over the course of the cycle, identify the most variable features, and cluster individual time series into groups with distinct characteristics. Applying CyHMMs to two real-world health-tracking datasets -- of menstrual cycle symptoms and physical activity tracking data -- yields important insights including which symptoms to expect at each point during the cycle. We also find that people fall into several groups with distinct cycle patterns, and that these groups differ along dimensions not provided to the model. For example, by modeling missing data in the menstrual cycles dataset, we are able to discover a medically relevant group of birth control users even though information on birth control is not given to the model.Comment: Accepted at WWW 201

Implementation of a real-time dance ability for mini maggie

The increasing rise of robotics and the growing interest in some fields like the human-robot interaction has triggered the birth a new generation of social robots that develop and expand their abilities. Much late research has focused on the dance ability, what has caused it to experience a very fast evolution. Nonetheless, real-time dance ability still remains immature in many areas such as online beat tracking and dynamic creation of choreographies. The purpose of this thesis is to teach the robot Mini Maggie how to dance real-time synchronously with the rhythm of music from the microphone. The number of joints of our robot Mini Maggie is low and, therefore, our main objective is not to execute very complex dances since our range of action is small. However, Mini Maggie should react with a low enough delay since we want a real-time system. It should resynchronise as well if the song changes or there is a sudden tempo change in the same song. To achieve that, Mini Maggie has two subsystems: a beat tracking subsystem, which tell us the time instants of detected beats and a dance subsystem, which makes Mini dance at those time instants. In the beat tracking system, first, the input microphone signal is processed in order to extract the onset strength at each time instant, which is directly related to the beat probability at that time instant. Then, the onset strength signal will be delivered to two blocks. The music period estimator block will extract the periodicities of the onset strength signal by computing the 4-cycled autocorrelation, a type of autocorrelation in which we do not only compute the similarity of a signal by a displacement of one single period but also of its first 4 multiples. Finally, the beat tracker takes the onset strength signal and the estimated periods real-time and decides at which time instants there should be a beat. The dance subsystem will then execute different dance steps according to several prestored choreographies thanks to Mini Maggie’s dynamixel module, which is in charge of more low-level management of each joint. With this system we have taught Mini Maggie to dance for a general set of music genres with enough reliability. Reliability of this system generally remains stable among different music styles but if there is a clear lack of minimal stability in rhythm, as it happens in very expressive and subjectively interpreted classical music, our system is not able to track its beats. Mini Maggie’s dancing was adjusted so that it was appealing even though there was a very limited range of possible movements, due to the lack of degrees of freedom.Ingeniería de Sistemas Audiovisuale

Care-Chair: Opportunistic health assessment with smart sensing on chair backrest

A vast majority of the population spend most of their time in a sedentary position, which potentially makes a chair a huge source of information about a person\u27s daily activity. This information, which often gets ignored, can reveal important health data but the overhead and the time consumption needed to track the daily activity of a person is a major hurdle. Considering this, a simple and cost-efficient sensory system, named Care-Chair, with four square force sensitive resistors on the backrest of a chair has been designed to collect the activity details and breathing rate of the users. The Care-Chair system is considered as an opportunistic environmental sensor that can track each and every activity of its occupant without any human intervention. It is specifically designed and tested for elderly people and people with sedentary job. The system was tested using 5 users data for the sedentary activity classification and it successfully classified 18 activities in laboratory environment with 86% accuracy. In an another experiment of breathing rate detection with 19 users data, the Care-Chair produced precise results with slight variance with ground truth breathing rate. The Care-Chair yields contextually good results when tested in uncontrolled environment with single user data collected during long hours of study. --Abstract, page iii