Design and validation of a low cost indoor environment quality data logger

Theme: Fifty years later: Revisiting the role of architectural science in design and practiceThe appraisal of indoor environment quality in residential dwellings presents a range of technical challenges. Indoor environment quality (IEQ) is often described as having thermal, visual, aural and olfactory dimensions, each of which is assessed subjectively by the resident. While it is possible to objectively assess physical parameters relating to each aspect of IEQ, either directly or indirectly, resident satisfaction with the environment is determined subjectively so must be inferred. In the field study of thermal comfort (FSTC) approach, objective physical measurements are collected simultaneously with resident preference and sensation information, usually via a diary or written survey. This research paper explores a new approach to residential IEQ appraisal which extends the FSTC approach to the visual, aural and olfactory dimensions using a low cost data collection system based upon the Arduino microcontroller platform. The paper describes the design developed, presents early validation results and draws preliminary conclusions.Andrew Carre, Terence Williamson and Veronica Soebart

Statics and dynamics of a cylindrical droplet under an external body force

We study the rolling and sliding motion of droplets on a corrugated substrate by Molecular Dynamics simulations. Droplets are driven by an external body force (gravity) and we investigate the velocity profile and dissipation mechanisms in the steady state. The cylindrical geometry allows us to consider a large range of droplet sizes. The velocity of small droplets with a large contact angle is dominated by the friction at the substrate and the velocity of the center of mass scales like the square root of the droplet size. For large droplets or small contact angles, however, viscous dissipation of the flow inside the volume of the droplet dictates the center of mass velocity that scales linearly with the size. We derive a simple analytical description predicting the dependence of the center of mass velocity on droplet size and the slip length at the substrate. In the limit of vanishing droplet velocity we quantitatively compare our simulation results to the predictions and good agreement without adjustable parameters is found.Comment: Submitted to the Journal of Chemical Physic

From centralized to decentralized approach for optimal Controller of Discrete Manufacturing Systems

International audienceThis paper deals with a comparison of centralized and decentralized approaches to obtain an optimal controller for discrete manufacturing systems. It is based on a modular modeling of the plant to avoid combinatory explosion found in centralized structure and a synthesis algorithm. From the local Plant Elements, local constraints are defined to build local supervisors. Local constraints restrict the system behavior within a desired specification. Global constraints are added to establish high level supervisors. The resulting automata are translated in a normalized language for implementation in a Programmable Logic Controller

Perceptions and attitudes towards shoulder padding and shoulder injury in rugby union

Objective To develop an understanding of the role of shoulder padding in preventing injuries in rugby by investigating player perceptions and attitudes towards shoulder padding and extending previous research into the nature of shoulder injuries in rugby. Methods A survey was distributed to current rugby players over 13 years old. Questions related to the participants' demographic, attitudes to shoulder padding and shoulder injury history. Results 616 rugby players responded to the survey. 66.1% of respondents had worn shoulder padding at some point during their career. Youth players (13-17 years old) and the older demographic (36+ years old) perceived shoulder padding to be more effective. 37.1% of respondents considered shoulder padding to be effective at preventing cuts and abrasions with 21.9% finding it very effective. 50.3% considered it to be effective at preventing contusion injury with 9.7% finding it very effective. 45.5% wore padding for injury prevention, while 19.2% wore padding to protect from reoccurring injury. 38.6% did not wear shoulder padding because they felt it was not needed for the game of rugby. Sprain/ ligament damage (57.5%) and bruising (55.5%) to the shoulder were the most commonly reported injury. Conclusions Research should focus on quantifying the injury preventive capabilities while also educating the rugby community on shoulder padding. Bruising, cuts and abrasion injuries to the shoulder are prevalent. The ability of shoulder padding to protect from these injuries should be further explored

Simulation and optimization of takeoff maneuvers of very flexible aircraft

A generic framework for the simulation of transient dynamics in nonlinear aeroelasticity is presented that is suitable for flexible aircraft maneuver optimization. Aircraft are modeled using a flexible multibody dynamics approach built on geometrically nonlinear composite beam elements, and the unsteady aerodynamics on their lifting surfaces is modeled using vortex lattices with free or prescribed wakes. The open loop response to commanded inputs and external constraints is then fed into a Bayesian optimization framework, which adaptively samples the configuration space to identify optimal maneuvers. As a representative example, the proposed approach is demonstrated on a catapult-assisted takeoff. The specific modeling challenges associated to that problem are first discussed, including the effect of aircraft flexibility. An optimality measure based on ground clearance and wing root loads is then defined. It is finally shown that the link that ramp-length constraints introduce between acceleration, release speed, and wing root loads is the main driver in the optimal solution

Two Cases of Study for Control Reconfiguration of Discrete Event Systems (DES)

International audienceIn this paper, we propose two cases of study for control reconfiguration of Discrete Event Systems. The main contributions are based on a safe centralized and distributed control synthesis founded on timed properties. In fact, if a sensor fault is detected, the controller of the normal behavior is reconfigured to a timed controller where the timed information replaces the information lost on the faulty sensor. Finally, we apply our contribution to a manufacturing system to illustrate our results and compare between the two frameworks

Checking diagnosability on centralized model of the system

International audienceIn this work, the problem of checking diagnosability on Discrete Event System (DES) is considered especially in centralized architecture. Many approaches in literature deals with diagnosability using one or more intermediate models. In this paper, we present a new model based diagnosability algorithms in the framework of set theory for deciding diagnosability, without any intermediate constructions or models and considering several faults at the same time

Exposing Multi-Relational Networks to Single-Relational Network Analysis Algorithms

Many, if not most network analysis algorithms have been designed specifically for single-relational networks; that is, networks in which all edges are of the same type. For example, edges may either represent "friendship," "kinship," or "collaboration," but not all of them together. In contrast, a multi-relational network is a network with a heterogeneous set of edge labels which can represent relationships of various types in a single data structure. While multi-relational networks are more expressive in terms of the variety of relationships they can capture, there is a need for a general framework for transferring the many single-relational network analysis algorithms to the multi-relational domain. It is not sufficient to execute a single-relational network analysis algorithm on a multi-relational network by simply ignoring edge labels. This article presents an algebra for mapping multi-relational networks to single-relational networks, thereby exposing them to single-relational network analysis algorithms.Comment: ISSN:1751-157

A wake-integral method for drag prediction

This paper describes the theoretical development and implementation issues of a far field induced drag extraction tool based on the Maskell integral. Far field methods provide an alternative to classical near field approach, offering the possibility of decompose drag contributions based on their physical source and improves prediction accuracy on coarse meshes. Instead of classical triangulation of intersection nodes contained in the cutting plane, a more regular adaptive mesh is implemented in order to improve flow reconstruction smoothness and accuracy. Both meshes results are compared and the influence of generation parameters of the bidimensional adaptive mesh is discussed. Numerical diffusion plays a major role in vortex decay, and because of that phenomena, a correction factor is needed in order to back as much as possible the cutting plane without loosing precision. Finally, Onera M6 tests are conducted, showing acceptable precision in drag prediction until seven or more chords downstream