Perfect Simulation of M/G/cM/G/c Queues

In this paper we describe a perfect simulation algorithm for the stable $M/G/c$ queue. Sigman (2011: Exact Simulation of the Stationary Distribution of the FIFO M/G/c Queue. Journal of Applied Probability, 48A, 209--213) showed how to build a dominated CFTP algorithm for perfect simulation of the super-stable $M/G/c$ queue operating under First Come First Served discipline, with dominating process provided by the corresponding $M/G/1$ queue (using Wolff's sample path monotonicity, which applies when service durations are coupled in order of initiation of service), and exploiting the fact that the workload process for the $M/G/1$ queue remains the same under different queueing disciplines, in particular under the Processor Sharing discipline, for which a dynamic reversibility property holds. We generalize Sigman's construction to the stable case by comparing the $M/G/c$ queue to a copy run under Random Assignment. This allows us to produce a naive perfect simulation algorithm based on running the dominating process back to the time it first empties. We also construct a more efficient algorithm that uses sandwiching by lower and upper processes constructed as coupled $M/G/c$ queues started respectively from the empty state and the state of the $M/G/c$ queue under Random Assignment. A careful analysis shows that appropriate ordering relationships can still be maintained, so long as service durations continue to be coupled in order of initiation of service. We summarize statistical checks of simulation output, and demonstrate that the mean run-time is finite so long as the second moment of the service duration distribution is finite.Comment: 28 pages, 5 figure

Le déclin de l’Empire américain et l’avenir des francophonies en périphérie : le cas de la Saskatchewan

La survie et l’épanouissement de la langue française au Canada aujourd’hui sont influencés par des tendances opposées : l’épanouissement et l’étiolement linguistiques. Ces tendances contradictoires sont autant mondiales que nationales. Ainsi dans certaines régions du Canada, et dans quelques parties du monde, le nombre de personnes parlant le français augmente. Au Canada, les droits des francophones s’accroissent sans cesse depuis les années 1960. Mais plusieurs régions à l’extérieur du Québec subissent des tendances démographiques inquiétantes qui conduisent à l’affaiblissement général des communautés et à la perte de la langue française. L’étude de cas type d’une région menacée, comme la Saskatchewan, devrait tenir compte de facteurs extérieurs qui influent sur les tendances internes de cette communauté. En particulier, ces facteurs doivent tenir compte des tendances mondiales concernant la langue française et de l’insertion de la Saskatchewan dans les contradictions du capitalisme avancé sous l’hégémonie américaine.The survival and vitality of the French language in Canada today are influenced by opposing trends towards linguistic épanouissement on the one hand and linguistic attenuation on the other. These contradictory trends are global as well as national. In certain regions of Canada and some parts of the world, the number of Francophones is increasing. In Canada, Francophone linguistic rights have been expanding since the 60s. But several regions outside Quebec are showing disturbing demographic trends that are leading to a general weakening of Francophone communities and a loss of the French language. A case study of one of these threatened regions, such as Saskatchewan, should take into account the external factors that influence this community’s internal trends. In particular, these external factors must factor in world trends in the use of French and where Saskatchewan sits within the contradictions of advanced capitalism under the American hegemony

Raman spectra and Magnetization of all-ferromagnetic superlattices grown on (110) oriented SrTiO3

Superlattices consist of two ferromagnets La0.7Sr0.3MnO3(LSMO)and SrRuO3(SRO) were grown in (110)-orientation on SrTiO3(STO) substrates. The x-ray diffraction and Raman spectra of these superlattices show the presence of in-plane compressive strain and orthorhombic structure of less than 4 u.c. thick LSMO spacer,respectively. Magnetic measurements reveal several features including reduced magnetization, enhanced coercivity, antiferromagnetic coupling, and switching from antiferromagnetic to ferromagnetic coupling with magnetic field orientations. These magnetic properties are explained by the observed orthorhombic structure of spacer LSMO in Raman scattering which occurs due to the modification in the stereochemistry of Mn at the interfaces of SRO and LSMO

Overview of microoptics: Past, present, and future

Through advances in semiconductor miniaturization technology, microrelief patterns, with characteristic dimensions as small as the wavelength of light, can now be mass reproduced to form high-quality and low-cost optical components. In a unique example of technology transfer, from electronics to optics, this capability is allowing optics designers to create innovative optical components that promise to solve key problems in optical sensors, optical communication channels, and optical processors

Relever le défi de la diversité : une comparaison des idéologies en éducation en contexte minoritaire et majoritaire au Nouveau-Brunswick et en Saskatchewan

En dépit d’efforts récents par les gouvernements fédéral et provinciaux et par le milieu associatif pour augmenter le nombre d’immigrants, les communautés francophones en milieu minoritaire au Canada en reçoivent très peu. En conséquence, très peu de programmes et de services particuliers existent pour les quelques élèves issus de l’immigration. Les défis sont particulièrement aigus pour les provinces où l’immigration est faible même du côté majoritaire. Dans cet article, nous faisons un inventaire des politiques ministérielles et des programmes scolaires touchant l’accueil et l’intégration des élèves immigrants, du côté anglophone en comparaison avec le côté francophone en Saskatchewan et au Nouveau-Brunswick. Nous constatons tout d’abord une certaine disparité entre les anglophones et les francophones, mais aussi un manque d’harmonisation entre les diverses mesures, qui demeurent généralement à un stade expérimental. Globalement, ces mesures se situent dans une approche idéologique de type multiculturaliste participative, c’est-à-dire où on tient compte des différences portées par les immigrants, mais surtout pour leur permettre individuellement de rejoindre les autres élèves. Toutefois, le manque d’encadrement de ces mesures et l’absence de programmes créent d’importantes disparités entre les écoles, même sur le plan de l’approche idéologique.Despite recent efforts by federal and provincial governments and the community milieu to increase the number of immigrants, French speaking sectors in Canadian minority areas receive very few. Consequently, few programs and specific services exist for the small number of immigrant students. The challenges are particularly acute for provinces with low immigration levels, even on the majority side. In this article, we make an inventory of ministerial policies and school programs in Saskatchewan and New-Brunswick geared to welcoming and integrating immigrant students in the English-speaking schools compared to the French-speaking schools. First of all, we notice a certain discrepancy between Anglophone and Francophone schools, along with a lack of harmonization among the various measures, which generally remain at an experimental stage. Overall, these measures lie in a participative and multiculturalist ideological approach, which take the immigrants’ differences into account and above all, allows them to reach out individually to other students. However, the lack of supervision for these measures and the absence of programs create considerable discrepancies among schools, even in terms of the ideological approach.A pesar de los recientes esfuerzos de los gobiernos federal y provincial y del medio asociativo tratando de aumentar el número de inmigrantes, las comunidades francófonas en medio minoritario en Canadá acogen muy pocos inmigrantes. Lógicamente, existen pocos programas y servicios particulares para los alumnos provenientes de la inmigración. Los desafíos son particularmente agudos en las provincias en donde la inmigración es débil, incluso del lado mayoritario. En este artículo, hemos inventariado las políticas ministeriales y los programas escolares relacionados con la recepción y la integración de alumnos inmigrantes, comparando el lado anglófono con el lado francófono en Saskatchewan y en Nuevo Brunswick. Por principio hemos constatado una cierta disparidad entre anglófonos y francófonos, así como la ausencia de armonización entre las diversas medidas, que invariablemente quedan en un estadio experimental. Globalmente, dichas medidas se sitúan al interior de un enfoque ideológico de tipo multicultural participativo, en el cual se toman en cuenta las diferencias propias de los inmigrantes, sobre todo con el fin de permitir a los alumnos de emparejarse con el resto del grupo. Sin embargo, la ausencia de directivas y de programas para dichas medidas, provocan disparidades importantes entre las escuelas, incluso en lo concerniente al enfoque ideológico

Binary optics: Trends and limitations

We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use

UV to NIR photon conversion in Nd-doped rutile and anatase titanium dioxide films for silicon solar cell application

Undoped and Nd-doped titanium dioxide anatase and rutile films have been grown by pulsed-laser deposition at 700 °C under 0.1 mbar O2. By selecting adequate substrates, TiO2 films doped with 1, 2 or 5 at.% Nd were grown and constituted with polycrystalline rutile, highly oriented (2 0 0) rutile film, or oriented (0 0 4) anatase. An UV to NIR photon conversion is evidenced in the films. Indeed, intense and well-resolved emission lines from Nd3+ have been observed upon excitation above the TiO2 bandgap at room temperature. The sensitised emission of Nd3+ is found to be much efficient in rutile than in anatase structure. Low temperature photoluminescence measurements lead to fine resolved peaks corresponding to the Nd3+ 4f transitions with different spectral characteristic according to the host matrix used. Photoluminescence dependence temperature evidences that the light emission from Nd3+ in anatase-based films is probably influenced by the presence of self-trapped excitons or by orbital interaction. Mechanisms of sensitisation host to Nd3+ are proposed for both matrixes. Finally, the Nd dopant concentration and the microstructure of TiO2 rutile films are found to affect the photoluminescence emission intensity. Rutile film (2 0 0) oriented is the most adapted host matrix to sensitise 1 at.% Nd3+ ions for an emission around 1064 nm making such Nd-doped layers interesting for photon conversion by down shifting process

Integrated Active Fire Retrievals and Biomass Burning Emissions Using Complementary Near-Coincident Ground, Airborne and Spaceborne Sensor Data

Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge between ground and spaceborne data sets providing high quality reference information to support satellite fire retrieval error analyses and fire emissions estimates. We found excellent agreement between peak fire radiant heat flux data (less than 1% error) derived from near-coincident ground radiometers and AMS. Both MODIS and GOES imager active fire products were negatively influenced by the presence of thick smoke, which was misclassified as cloud by their algorithms, leading to the omission of fire pixels beneath the smoke, and resulting in the underestimation of their retrieved fire radiative power (FRP) values for the burn plot, compared to the reference airborne data. Agreement between airborne and spaceborne FRP data improved significantly after correction for omission errors and atmospheric attenuation, resulting in as low as 5 difference between AquaMODIS and AMS. Use of in situ fuel and fire energy estimates in combination with a collection of AMS, MODIS, and GOES FRP retrievals provided a fuel consumption factor of 0.261 kg per MJ, total energy release of 14.5 x 10(exp 6) MJ, and total fuel consumption of 3.8 x 10(exp 6) kg. Fire emissions were calculated using two separate techniques, resulting in as low as 15 difference for various specie

The chicken gene nomenclature committee report

Comparative genomics is an essential component of the post-genomic era. The chicken genome is the first avian genome to be sequenced and it will serve as a model for other avian species. Moreover, due to its unique evolutionary niche, the chicken genome can be used to understand evolution of functional elements and gene regulation in mammalian species. However comparative biology both within avian species and within amniotes is hampered due to the difficulty of recognising functional orthologs. This problem is compounded as different databases and sequence repositories proliferate and the names they assign to functional elements proliferate along with them. Currently, genes can be published under more than one name and one name sometimes refers to unrelated genes. Standardized gene nomenclature is necessary to facilitate communication between scientists and genomic resources. Moreover, it is important that this nomenclature be based on existing nomenclature efforts where possible to truly facilitate studies between different species. We report here the formation of the Chicken Gene Nomenclature Committee (CGNC), an international and centralized effort to provide standardized nomenclature for chicken genes. The CGNC works in conjunction with public resources such as NCBI and Ensembl and in consultation with existing nomenclature committees for human and mouse. The CGNC will develop standardized nomenclature in consultation with the research community and relies on the support of the research community to ensure that the nomenclature facilitates comparative and genomic studies