Efficient cloud tracing: From very high level to very low level

With the increase of cloud infrastructure complexity, the origin of service deterioration is difficult to detect because issues may occur at the different layer of the system. We propose a multi-layer tracing approach to gather all the relevant information needed for a full workflow analysis. The idea is to collect trace events from all the cloud nodes to follow users' requests from the cloud interface to their execution on the hardware. Our approach involves tracing OpenStack's interfaces, the virtualization layer, and the host kernel space to perform analysis and show abnormal tasks and the main causes of latency or failures in the system. Experimental results about virtual machines live migration confirm that we are able to analyse services efficiency by locating platforms' weakest links

Fiber-level bi-axial braid simulation for braid-trusion

Braid-trusion is a manufacturing process using a braided textile preform that is pulled into a pultrusion die. This process produces constant cross-section beams having reinforcement fibers oriented along the braid angle. The bi-axial braids are made from commingled yarns mixing carbon fibers and thermoplastic filaments. The bi-axial braid architecture is locked by the contacts between the bulky carbon/thermoplastic yarns. During pultrusion, the thermoplastic filaments melt. At this moment, the processing tensile loads adjust the braid architecture. The braid angle and the braid diameter reduces by reaching another locked state. This second locked state is driven by contacts between carbon yarns. The aim of this research is to model the braid deformation at the fiber scale using a non-linear finite element method. The model geometry is set up by the helix sinusoidal relations of the yarns path along a braid pitch. The braid large deformation is precisely modeled via a bundle of three-dimensional beam elements. The intertwined fibers contacts are modeled within a dynamic explicit solution. The model is validated with CT Scans of carbon fiber braids. This work will help the design of braid architecture for braid-trusion manufacturing

P0006: Hearts on Fire

ABSTRACT: The left ventricle is the heart's powerhouse, responsible for pumping oxygen- and nutrient-rich blood to each and every tissue throughout the body. By consequence, diseases affecting this laborious chamber are not only more common but often more serious. The fluid dynamics in the healthy left ventricle is characterized by the impulsive formation of a vortex ring during its filling phase which facilitates the following ejection with very little energy loss. In the case of a leaking aortic valve however, the left ventricle will fill from two sides, resulting in the interaction between two pulsatile jets in a confined elastic vessel, marking a new and unique fluid dynamics problem. Here, we show the backward finite-time Lyapunov exponent in the healthy and diseased left ventricles, revealing the attracting Lagrangian coherent structures associated with the aortic (A) and mitral (M) inflows. The background shows the time-frequency spectra of velocity signals over one cardiac cycle taken at the entrance of the mitral (right) and aortic (left) inflows for the healthy (top) and diseased (bottom) cases. The overlay and perceptually-uniform colormap (thanks to Stéfan van der Walt and Nathaniel Smith) are such that the high frequency bursts (up to 200 Hz) occurring early in the filling phase give the appearance of fire

Teamwork in Crossdisciplinarity

ABSTRACT: The École Polytechnique de Montréal has integrated an approach of teamwork in its twelve engineering programs, in the bachelor's degree program since 2005. Students must take a compulsory 45 hour course on teamwork and are then accompanied with team coaching throughout the four years program, in all the engineering integration projects. These integration projects are generally ones in which, over a session, the students work in teams to conceive an engineering project. Within the framework of these projects (1 per year), a group communication specialist meets every team for approximately 60 minutes. This process promotes the transfer of the accumulated knowledge acquired in the teamwork course to their projects and helps identify the group processes at play in their teamwork dynamics. The objective pursued by this conference is to present the innovative formula used by the École Polytechnique de Montréal and to demonstrate by clear examples how it allows the development of skills in teamwork in all the scientific disciplines

Teamwork in Crossdisciplinarity

ABSTRACT: The École Polytechnique de Montréal has integrated an approach of teamwork in its twelve engineering programs, in the bachelor's degree program since 2005. Students must take a compulsory 45 hour course on teamwork and are then accompanied with team coaching throughout the four years program, in all the engineering integration projects. These integration projects are generally ones in which, over a session, the students work in teams to conceive an engineering project. Within the framework of these projects (1 per year), a group communication specialist meets every team for approximately 60 minutes. This process promotes the transfer of the accumulated knowledge acquired in the teamwork course to their projects and helps identify the group processes at play in their teamwork dynamics. The objective pursued by this conference is to present the innovative formula used by the École Polytechnique de Montréal and to demonstrate by clear examples how it allows the development of skills in teamwork in all the scientific disciplines

Characterising Annual Behaviour of Carsharing Users in Montreal

ABSTRACT: Carsharing is one of the emerging modes of transportation in the recent years, as a pointer to the fact that owning a private car is not all we need for the sake of travelling. Using k-means clustering and Principal Component Analysis, the purpose of this paper is to study the behaviour of the Communauto regular-service carsharing users in Montreal over a year (2014) and find the usage patterns in each cluster. Also, by having the Communauto customer features available, the characteristics of the customers in each cluster will be defined, which eventually ends in customer profiles. The k-means clustering results show that the Communauto regular-service carsharing users are divided into nine different clusters. Some of the clusters patterns are similar during the weeks and some are similar during a year, but none of them are similar during week and year. So, each cluster has a unique usage pattern over the weeks and the year. Furthermore, the resulting clusters are ordered from highly intensive users to the occasional ones based on the frequency of carsharing usage over one year

Predicting carsharing station-based trip generation using a growth model

ABSTRACT: Carsharing is a service that allows members to rent cars for a limited time. In Montreal, Quebec, Canada, two types of services exist: a station-based and a free-floating service. This paper proposes a trip generation model for the station-based service of the Communauto carsharing operator for 2016. To better understand relations between space and time, a growth model is used, considering these factors at different levels. For example, some factors can impact all stations similarly, while other factors may impact each station differently. Thus, this model allows to consider both spatial and temporal variables allowing more precise estimations. The aim of this research is to estimate carsharing trip generation at the station level and provide insights into the impacts of implementing new stations on demand. A step-by-step approach was adopted to define the best predictive model for the use of carsharing stations. While more complex model formulations need to be tested to enhance the analysis, the final growth model obtained indicates that, in addition to the number of vehicles available at the stations, several exogenous factors have a significant impact on the trip generation rate of a carsharing station. For instance, the model shows that demographic factors, walkability level and number of bus stations have significant impacts on the use of carsharing stations

Using 5 parallel passive data streams to report on a wide range of mobility options

ABSTRACT: Montreal welcomes a variety of transportation options: transit, carsharing, bikesharing, taxi, etc. In the recent years, the “new” alternatives have gained market shares and it has become critical to understand the role each mode plays in the daily mobility of people as well as their interactions. This paper presents an analysis process of passive data streams and a typology of typical days of usage of these modes using clustering techniques. It shows that the most important attributes determining the type of multimodal usage day are type of day (working / non-working), temperature, fuel price and precipitations