PriDyn: Enabling Differentiated I/O Services in Cloud Using Dynamic Priorities

Virtualization is one of the key enabling technologies for Cloud computing. Although it facilitates improved utilization of resources, virtualization can lead to performance degradation due to the sharing of physical resources like CPU, memory, network interfaces, disk controllers, etc. Multi-tenancy can cause highly unpredictable performance for concurrent I/O applications running inside virtual machines that share local disk storage in Cloud. Disk I/O requests in a typical Cloud setup may have varied requirements in terms of latency and throughput as they arise from a range of heterogeneous applications having diverse performance goals. This necessitates providing differential performance services to different I/O applications. In this paper, we present PriDyn, a novel scheduling framework which is designed to consider I/O performance metrics of applications such as acceptable latency and convert them to an appropriate priority value for disk access based on the current system state. This framework aims to provide differentiated I/O service to various applications and ensures predictable performance for critical applications in multi-tenant Cloud environment. We demonstrate through experimental validations on real world I/O traces that this framework achieves appreciable enhancements in I/O performance, indicating that this approach is a promising step towards enabling QoS guarantees on Cloud storage.

Hydrological importance of sacred forest fragments in Central Western Ghats of India

Sacred groves are patches of forests of special spiritual significance to humans, offering also a diverse range of ecological and environmental services. We have attempted here to understand the local hydrological dynamics of a sacred forest, in terms of the benefits the village community derive, in central Western Ghats region of India. A comparative assessment has been made between two small watersheds in terms of their landscape structure (woody species composition) with soil water properties and availability of water in the respective downstream villages. The result shows that, sacred site with more primeval vegetation has close association with soil moisture in comparison to non-sacred site during dry spell of the year. The higher soil moisture ensures year long availability of water in the downstream village of the sacred site which facilitates farming of commercial crops with higher economic returns to the farmers, unlike the farmers in the other village where they face water crisis during the lean season. The study emphasizes the need for conservation endeavour on sacred groves highlighting its potential for water conservation at local and regional levels.

Computing abuse related damages in the case of new entry: An illustration for the Directory Enquiry Services market

A number of European countries, among which the UK and Spain, have opened up their Directory Enquiry Services (DQs, or 118AB) market to competition. We analyse the Spanish case, where both local and foreign firms challenged the incumbent as of April 2003. We argue that the incumbent had the ability to abuse its dominant position, and that it was a perfectly rational strategy. In short,the incumbent raised its rivals' costs directly by providing an inferior quality version of the (essential) input, namely the incumbent's subscribers' database. We illustrate how it is possible to quantify the effect of abuse in situation were the entrant has no previous history in the market. To do this, we use the UK experience to construct the relevant counterfactual, that is the "but for abuse" scenario. After controlling for relative prices and advertising intensity, we find that one of the foreign entrants achieved a Spanish market share of only half of what it would have been in the absence of abuse.

La influencia del factor dimensión en la pertenencia a centrales de compra por parte del pequeño comercio

[ES] Desde hace varios años, el pequeño comercio en España y en otros países europeos viene enfrentándose a un entorno de creciente concurrencia, con la irrupción de nuevas formas comerciales más integradas vertical u horizontalmente, y mejor preparadas para competir en precio y variedad. Ante este hecho, las centrales de compra se ofrecen como una alternativa tendente a acortar distancias en estas dos cuestiones, a la vez que buscan la prestación de ciertos servicios que ayuden al pequeño comerciante a gestionar más eficaz y eficientemente su negocio.

Apuntes jurídicos sobre el paisaje lingüístico en Euskal Herria

This paper is a study of place-names and signs in the Basque Country from the point of view of language law. These are matters that relate to both the status and corpus of language and contribute to the formation of the language landscape,» After a brief historical introduction, the author focuses on the factors that bear on signs and the language 1andscape: the cornpetence factor and the language factor. The description of the latter leads the author to a discussion of the existing language system, in which the Spanish and Basque sharing official status does not necessarily entail the obligation to use both languages at the same time. Using this discussion as a frame of reference, the au- thor analyses place-names, traffic signals and signs. As for place-names, the existing rules are deemed rigid and lacking in ambition, in that they do not pursue the dissemination of official Basque forms. In traffic signaIs, Basque has to appear alongside Spanish, which is required by Spanish legislation, although this bilingualism excludes place-names that have an official Basque form only. With regard to signs, the author analyses public premises, companies licensed to provide public services and the private sector. For public premises there is no specific regulation, but the status of Basque as an autochthonous language, together with the identification and informatíon purposes of signs, could support the exclusive use of this language, According to the author , companies licensed to provide public services should observe the same language system as the goverment and therefore promote the use of Basque. Finally, in the private sector, the author upholds the legitimacy of measures to promote Basque language use such as tax allowances and exemptions in advertising and commercial signs.

Gestión comercial de una emisora comarcal. El caso de radio Sobrarbe

[ES] Radio Sobrarbe es una emisora radiofónica comarcal perteneciente a la mancomunidad de Sobrarbe (Huesca). La plantilla de la misma está formada por dos personas, si bien cuenta para la realización y emisión de programas con colaboradores que trabajan para ella de forma totalmente altruista.

Evaluation of Several Commercial Algicides for Control of Odor-producing Cyanobacteria

The production of certain odorous metabolites is an undesirable attribute of cyanobacteria (blue-green algae) growth in aquaculture ponds [e.g., channel catfish(Ictalurus punctatus)] and in drinking water reservoirs. The most common odorous compounds encountered in catfish aquaculture are geosmin (trans-1,10-dimethyltrans-9-decalol) and 2-methylisoborneol(exo-1,2,7,7-tetramethylbicyclo[2.2.1]heptan-2-ol). These compounds are also frequently encountered worldwide in reservoirs and aqueducts used for municipal drinking water systems(Schrader et al. 2002). In this study, several algicides were evaluated using a rapid bioassay to determine their effectiveness in controlling the MIB-producing cyanobacterium Oscillatoria perornata from a west Mississippi catfish pond and the MIBproducing Pseudanabaena sp. (strain LW397) from Lake Whitehurst, Virginia, used as a city water supply reservoir. The cyanobacterium Oscillatoria agardhii , not a MIB-producer, and the green alga Selenastrum capricornutum , found in catfish ponds in the southeastern United States, were included in the bioassay to help determine potential broad-spectrum toxicity of the commercial products. (PDF has 3 pages.)