Static-priority scheduling over wireless networks with multiple broadcast domains

We propose a wireless medium access control (MAC) protocol that provides static-priority scheduling of messages in a guaranteed collision-free manner. Our protocol supports multiple broadcast domains, resolves the wireless hidden terminal problem and allows for parallel transmissions across a mesh network. Arbitration of messages is achieved without the notion of a master coordinating node, global clock synchronization or out-of-band signaling. The protocol relies on bit-dominance similar to what is used in the CAN bus except that in order to operate on a wireless physical layer, nodes are not required to receive incoming bits while transmitting. The use of bit-dominance efficiently allows for a much larger number of priorities than would be possible using existing wireless solutions. A MAC protocol with these properties enables schedulability analysis of sporadic message streams in wireless multihop networks.

Procréation assistée et filiation : enjeux et solutions en Suisse et au Québec

En janvier 2007, à 28 ans, Louise Brown est devenue maman. Trente ans, c'est le temps qu'il faut à une génération pour se renouveler. C'est aussi le temps, si bref à l'échelle de l'histoire, pour que les bouleversements induits par la science et les moeurs au ~e siècle modifient profondément le visage de la famille et de son ciment le plus intime, la filiation. Ce travail rend compte de la manière dont le droit appréhende ces changements dans des sociétés occidentales de plus en plus tiraillées entre leurs racines judéo-chrétiennes et leurs aspirations technologiques. Il cherche à comprendre la place du droit dans les nouveaux édifices familiaux et à évaluer la qualité des solutions que celui-ci propose face aux enjeux multiples et complexes de la procréation assistée. Il s'attache pour ce faire à l'examen de deux juridictions partageant un héritage commun à bien des égards, mais suivant des voies normatives différentes : la Suisse et le Québec. À ce titre, il définit des outils conceptuels nécessaires à la compréhension de la notion de filiation; il rend compte de la façon dont le droit a manipulé ces outils en régissant l'établissement de la filiation, la preuve de la filiation et la procréation assistée à proprement parler; et il conclut par une évaluation critique des solutions envisagées dans les deux systèmes étudiés. Il met ainsi en exergue les enjeux de la procréation assistée pour le droit de la filiation et la grande palette de solutions législatives envisageables. Il démontre que deux systèmes de droit peuvent traduire des préoccupations partagées par des dispositions diamétralement opposées. En particulier, l'égalité, la liberté et le bien de l'enfant se concrétisent selon des conceptions distinctes. L'attachement aux institutions se manifeste à des degrés variables. Les innovations scientifiques sont accueillies avec un enthousiasme plus ou moins soutenu. Tous ces facteurs sont les détenninants des familles suisse et québécoise, qui, pour s'être longtemps ressemblées, prennent aujourd'hui des chemins différents...mais pas irrémédiablement irréconciliables.

Les facilitateurs et les solutions à la pratique optimale des médecins dans le traitement de l’asthme

OBJECTIF : Déterminer les principales solutions qui facilitent la pratique optimale des médecins dans le traitement de l’asthme, incluant la prescription d’un médicament de contrôle à long terme et l’utilisation de plans d’action écrits. MÉTHODOLOGIE: Des entrevues individuelles semi-structurées ont été menées avec des médecins de différentes spécialités (médecins de famille, pédiatres, urgentologues, pneumologues et allergologues). Ces entrevues ont été transcrites puis analysées qualitativement de manière indépendante par deux chercheures qualifiées. RÉSULTATS : Quarante-deux médecins ont été interviewés. Un total de 867 facilitateurs et solutions ont été exprimés, répondant à trois de leurs besoins: (1) avoir du soutien dans la prestation de soins optimaux, (2) être habileté à aider et motiver les patients à suivre leurs recommandations et (3) avoir l’opportunité d’offrir des services efficients. À partir de ces données, une taxonomie de facilitateurs et de solutions comprenant dix catégories a également été développée. CONCLUSION : Les médecins ont proposé une multitude de facilitateurs et de solutions pour soutenir la pratique optimale. Ils varient essentiellement selon la spécialité et le comportement visé (prescription de médicaments de contrôle à long terme, utilisation de plans d’autogestion écrits et la gestion générale de l’asthme). Cela fait ressortir l’importance d’effectuer le choix des interventions en étroite collaboration avec les utilisateurs de connaissances afin d’obtenir des solutions qui soient perçues comme faisables et applicables, ayant ainsi potentiellement plus de chances de mener à un changement de pratique. La nouvelle taxonomie offre la possibilité d’utiliser un langage commun pour classifier les facilitateurs et les solutions.

Multisite Research Ethics Review: Problems and Potential Solutions

Article

Multiple Integration

Exercises and solutions on double integration. Diagrams for the questions are all together in the support.zip file, as .eps files

Search space pruning and global optimization of multiple gravity assist trajectories with deep space manoeuvres

This paper deals with the design of optimal multiple gravity assist trajectories with deep space manoeuvres. A pruning method which considers the sequential nature of the problem is presented. The method locates feasible vectors using local optimization and applies a clustering algorithm to find reduced bounding boxes which can be used in a subsequent optimization step. Since multiple local minima remain within the pruned search space, the use of a global optimization method, such as Differential Evolution, is suggested for finding solutions which are likely to be close to the global optimum. Two case studies are presented.

Multiple diversity measures to identify complementary conservation areas for the Baja California peninsular cacti

The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km2. Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.

Grid computing solutions for distributed repositories of protein folding and unfolding simulations

The P-found protein folding and unfolding simulation repository is designed to allow scientists to perform analyses across large, distributed simulation data sets. There are two storage components in P-found: a primary repository of simulation data and a data warehouse. Here we demonstrate how grid technologies can support multiple, distributed P-found installations. In particular we look at two aspects, first how grid data management technologies can be used to access the distributed data warehouses; and secondly, how the grid can be used to transfer analysis programs to the primary repositories --- this is an important and challenging aspect of P-found because the data volumes involved are too large to be centralised. The grid technologies we are developing with the P-found system will allow new large data sets of protein folding simulations to be accessed and analysed in novel ways, with significant potential for enabling new scientific discoveries.

Numerical analyses of Runge–Kutta implicit–explicit schemes for horizontally explicit, vertically implicit solutions of atmospheric models

With the prospect of exascale computing, computational methods requiring only local data become especially attractive. Consequently, the typical domain decomposition of atmospheric models means horizontally-explicit vertically-implicit (HEVI) time-stepping schemes warrant further attention. In this analysis, Runge-Kutta implicit-explicit schemes from the literature are analysed for their stability and accuracy using a von Neumann stability analysis of two linear systems. Attention is paid to the numerical phase to indicate the behaviour of phase and group velocities. Where the analysis is tractable, analytically derived expressions are considered. For more complicated cases, amplification factors have been numerically generated and the associated amplitudes and phase diagnosed. Analysis of a system describing acoustic waves has necessitated attributing the three resultant eigenvalues to the three physical modes of the system. To do so, a series of algorithms has been devised to track the eigenvalues across the frequency space. The result enables analysis of whether the schemes exactly preserve the non-divergent mode; and whether there is evidence of spurious reversal in the direction of group velocities or asymmetry in the damping for the pair of acoustic modes. Frequency ranges that span next-generation high-resolution weather models to coarse-resolution climate models are considered; and a comparison is made of errors accumulated from multiple stability-constrained shorter time-steps from the HEVI scheme with a single integration from a fully implicit scheme over the same time interval. Two schemes, “Trap2(2,3,2)” and “UJ3(1,3,2)”, both already used in atmospheric models, are identified as offering consistently good stability and representation of phase across all the analyses. Furthermore, according to a simple measure of computational cost, “Trap2(2,3,2)” is the least expensive.

Heuristics for the one-dimensional cutting stock problem with limited multiple stock lengths

This paper deals with the classical one-dimensional integer cutting stock problem, which consists of cutting a set of available stock lengths in order to produce smaller ordered items. This process is carried out in order to optimize a given objective function (e.g., minimizing waste). Our study deals with a case in which there are several stock lengths available in limited quantities. Moreover, we have focused on problems of low demand. Some heuristic methods are proposed in order to obtain an integer solution and compared with others. The heuristic methods are empirically analyzed by solving a set of randomly generated instances and a set of instances from the literature. Concerning the latter. most of the optimal solutions of these instances are known, therefore it was possible to compare the solutions. The proposed methods presented very small objective function value gaps. (C) 2008 Elsevier Ltd. All rights reserved.

Electricity Supply Solutions for an Educational Center in Tanzania

The aim of this study was to investigate electricity supply solutions for an educationalcenter that is being built in Chonyonyo Tanzania. Off-grid power generation solutions andfurther optimization possibilities were studied for the case.The study was done for Engineers Without Borders in Sweden. Who are working withMavuno Project on the educational center. The school is set to start operating in year 2015with 40 girl students in the beginning. The educational center will help to improve genderequality by offering high quality education in a safe environment for girls in rural area.It is important for the system to be economically and environmentally sustainable. Thearea has great potential for photovoltaic power generation. Thus PV was considered as theprimary power generation and a diesel generator as a reliable backup. The system sizeoptimization was done with HOMER. For the simulations HOMER required componentdata, weather data and load data. Common components were chose with standardproperties, the loads were based on load estimations from year 2011 and the weather datawas acquired from NASA database. The system size optimization result for this base casewas a system with 26 kW PW; 5.5 kW diesel generator, 15 kW converter and 112 T-105batteries. The initial cost of the system was 55 875 €, the total net present cost 92 121 €and the levelized cost of electricity 0.264 €/kWh.In addition three optimization possibilities were studied. First it was studied how thesystem should be designed and how it would affect the system size to have night loads(security lights) use DC and could the system then be extended in blocks. As a result it wasfound out that the system size could be decreased as the inverter losses would be avoided.Also the system extension in blocks was found to be possible. The second study was aboutinverter stacking where multiple inverters can work as one unit. This type of connectionallows only the required number of inverters to run while shutting down the excess ones.This would allow the converter-unit to run with higher efficiency and lower powerconsumption could be achieved. In future with higher loads the system could be easilyextendable by connecting more inverters either in parallel or series depending on what isneeded. Multiple inverters would also offer higher reliability than using one centralizedinverter. The third study examined how the choice of location for a centralized powergeneration affects the cable sizing for the system. As a result it was found that centralizedpower generation should be located close to high loads in order to avoid long runs of thickcables. Future loads should also be considered when choosing the location. For theeducational center the potential locations for centralized power generation were found outto be close to the school buildings and close to the dormitories.

Oral zinc sulfate solutions inhibit sweet taste perception

We investigated the ability of zinc sulfate (5, 25, 50 mM) to inhibit the sweetness of 12 chemically diverse sweeteners, which were all intensity matched to 300 mM sucrose [800 mM glucose, 475 mM fructose, 3.25 mM aspartame, 3.5 mM saccharin, 12 mM sodium cyclamate, 14 mM acesulfame-K, 1.04 M sorbitol, 0.629 mM sucralose, 0.375 mM neohesperidin dihydrochalcone (NHDC), 1.5 mM stevioside and 0.0163 mM thaumatin]. Zinc sulfate inhibited the sweetness of most compounds in a concentration dependent manner, peaking with 80% inhibition by 50 mM. Curiously, zinc sulfate never inhibited the sweetness of Na-cyclamate. This suggests that Na-cyclamate may access a sweet taste mechanism that is different from the other sweeteners, which were inhibited uniformly (except thaumatin) at every concentration of zinc sulfate. We hypothesize that this set of compounds either accesses a single receptor or multiple receptors that are inhibited equally by zinc sulfate at each concentration.

Pareto archived simulated annealing for single machine job shop scheduling with multiple objectives

In this paper, the single machine job shop scheduling problem is studied with the objectives of minimizing the tardiness and the material cost of jobs. The simultaneous consideration of these objectives is the multi-criteria optimization problem under study. A metaheuristic procedure based on simulated annealing is proposed to find the approximate Pareto optimal (non-dominated) solutions. The two objectives are combined in one composite utility function based on the decision maker’s interest in having a schedule with weighted combination. In view of the unknown nature of the weights for the defined objectives, a priori approach is applied to search for the non-dominated set of solutions based on the Pareto dominance. The obtained solutions set is presented to the decision maker to choose the best solution according to his preferences. The performance of the algorithm is evaluated in terms of the number of non-dominated schedules generated and the proximity of the obtained non-dominated front to the true Pareto front. Results show that the produced solutions do not differ significantly from the optimal solutions.

Hydrogen bonded block copolymer systems : from microphase separation in solid state to self-assembly in aqueous solutions

Block copolymer systems with hydrogen bonding interactions have received relatively little attention. Recently, we have investigated the self-assembly and phase separation in such block copolymer systems with an attempt to elucidate the role of hydrogen bonding interactions both theoretically and experimentally [1-4]. In A-b-B/C diblock copolymer/homopolymer systems, the phase behavior was theoretically analyzed according to the random phase approximation and correlated with hydrogen bonding interactions in terms of the difference in inter-association constants (K). To examine how the hydrogen bonding determines the self-assembly and morphological transitions in these systems, we have introduced the K values as a new variable into the phase diagram which we established for the first time (Fig. 1). Multiple vesicular morphologies were formed in aqueous solution of A-b-B/A-b-C diblock copolymer complexes of PS-b-PAA and PS-b-PEO. Interconnected compound vesicles (ICCVs) were observed for the first time as a new morphology (Fig. 2), along with other aggregated nanostructures including vesicles, multilamellar vesicles, thick-walled vesicles and irregular aggregates. Complexation of two amphiphilic diblock copolymers provides a viable approach to vesicles in aqueous media.

Real solutions number of the switching angles in the selective harmonic eliminated PWM

With the purpose of solving the real solutions number of the nonlinear transcendental equations in the selective harmonic eliminated PWM (SHEPWM) technology, the nonlinear transcendental equations were transformed to a set of polynomial equations with a set of inequality constraints using the multiple-angle formulas, an analytic method based on semi-algebraic systems machine proving algorithm was proposed to classify the real solution number of the switching angles. The complete classifications of the real solution number and the analytic boundary point of the single phase and three phases SHEPWM inverter with switch points of N=3 and the single phase SHEPWM inverter with switch points of N=4 are obtained. The results indicate that the relationship between the modulation ratio and the real solution number can be demonstrated theoretically by this method, which has great implications for the solution procedure of switching angles and the improvement of harmonic elimination effects of the inverter.