Système de suivi des appels d'offres

Face au nombre croissant d'appels d'offres générés dans la division, tant pour le projet LHC que pour l'activité courante, il s'avère désormais nécessaire de mettre en place un système de suivi rigoureux. Il s'agit de fournir au chef de division une information précise en temps réel de la situation de chaque appel d'offres, permettant ainsi de garantir le respect des procédures CERN d'adjudication. Ceci passe par une centralisation sous format papier de tous les documents techniques et commerciaux dans leur dernière version. Toutes ces informations doivent également être intégrées au sein d'un outil informatique adapté. Ce programme devra ainsi dégager automatiquement le degré d'avancement des différents appels d'offres et mettre en évidence les éventuels écarts et dysfonctionnements par rapport à la procédure. Ce papier insistera enfin sur l'importance de la gestion des flux d'information et les moyens mis en oeuvre pour les canaliser

Logistique de transport pour le projet LHC: enseignements des premiers secteurs

Ce papier dresse un premier bilan de la logistique de transport mise en place pour l'installation du LHC. Les moyens de planification mis en oeuvre seront tout d'abord évoqués avec notamment les réunions avec les groupes utilisateurs, l'élaboration de procédures de transport, la génération de listings d'articles à transporter ou encore l'établissement d'un planning des ressources. Cependant, les premiers travaux d'installation du LHC ont fait apparaître des divergences importantes entre le planning logistique établi et la réalité du terrain. Ces écarts seront analysés, qu'il s'agisse de différences sur le volume de matériel à acheminer, d'opérations non planifiées, de changements de plannings entraînant de longues et délicates traversées de chantiers ou de manque de planification des besoins en personnel dans certaines zones. Tous ces enseignements acquis au cours des premiers travaux devraient permettre de dégager des voies d'amélioration à mettre en place pour les prochains secteurs

Notes on acyclic orientations and the shelling lemma

AbstractIn this paper we study two lemmas on acyclic orientations and totally cyclic orientations of a graph, which can be derived from the shelling lemma in vector subspaces. We give simple graph theoretical proofs as well as a proof by the interpretations of the shelling lemma in the special setting of graphs. Furthermore, we present similar interpretations of closely related theorems in vector subspaces, which do not seem to admit simple graph theoretical proofs

Locating leak detecting sensors in a water distribution network by solving prize-collecting Steiner arborescence problems

We consider the problem of optimizing a novel acoustic leakage detection system for urban water distribution networks. The system is composed of a number of detectors and transponders to be placed in a choice of hydrants such as to provide a desired coverage under given budget restrictions. The problem is modeled as a particular Prize-Collecting Steiner Arborescence Problem. We present a branch-and-cut-and-bound approach taking advantage of the special structure at hand which performs well when compared to other approaches. Furthermore, using a suitable stopping criterion, we obtain approximations of provably excellent quality (in most cases actually optimal solutions). The test bed includes the real water distribution network from the Lausanne region, as well as carefully randomly generated realistic instance

Impact des incendies sur l'avifaune. Gestion du paysage et conservation de la biodiversité animale.

Sur les reliefs des arrières pays méditerranéens, la déprise rurale a pour conséquence une progression générale de la végétation ligneuse. Mais cette progression spontanée est fréquemment interrompue par des incendies. La fermeture lente, ou au contraire l'ouverture brutale, du paysage qui résulte de l'abandon ou des incendies s'accompagnent de changements avifaunistiques importants, qui ont fait l'objet d'analyses statistiques précises

Handling and Transport of Oversized Accelerator Components and Physics Detectors

For cost, planning and organisational reasons, it is often decided to install large pre-built accelerators components and physics detectors. As a result surface exceptional transports are required from the construction to the installation sites. Such heavy transports have been numerous during the LHC installation phase. This paper will describe the different types of transport techniques used to fit the particularities of accelerators and detectors components (weight, height, acceleration, planarity) as well as the measurement techniques for monitoring and the logistical aspects (organisation with the police, obstacles on the roads, etc). As far as oversized equipment is concerned, the lowering into the pit is challenging, as well as the transport in tunnel galleries in a very scare space and without handling means attached to the structure like overhead travelling cranes. From the PS accelerator to the LHC, handling systems have been developed at CERN to fit with these particular working conditions. This paper will expose the operating conditions of the main transport equipments used at CERN in PS, SPS and LHC tunnels

Breeding ecology of the Iranian ground jay (Podoces pleskei)

Although Podoces pleskei is the only endemic bird of Iran, little information exists on its ecological features, population dynamics and threats that concern it. This species occurs in desert and semi desert areas, mostly on the Iranian plateau, though its range spreads southeast ward to the Iran- Pakistan border. In this research, a total of 52 nests were studied in three locations, the “Ghare Tappe”, “Marvast” and “Mehrano” region, from 2005 to 2008. Breeding habits, nest characteristics, hatching features, clutch size, length of incubation time, nesting period and features of the chicks were observed in the three locations and were analyzed using analysis of variance (ANOVA). To compare breeding success among the three study areas, Z test was applied. This bird builds its nest at the top of and within the denser parts of plants, particularly Atraphaxis spinosa, Ephedra intermedia and Zygophyllum eurypterum. At times of danger, they hide beneath shrubs. Z-tests showed that the breeding success of this bird varied between Marvast and Mehrano. The greatest cause of nest failure and chick mortality was the transcaspian desert monitor (Varanus griseus caspius), which feeds on the eggs and chicks.Key words: Breeding ecology, Pleske’s ground jay, nest characteristics, clutch size, nest success, threat

Locating leak detecting sensors in a water distribution network by solving prize-collecting Steiner arborescence problems

We consider the problem of optimizing a novel acoustic leakage detection system for urban water distribution networks. The system is composed of a number of detectors and transponders to be placed in a choice of hydrants such as to provide a desired coverage under given budget restrictions. The problem is modeled as a particular Prize-Collecting Steiner Arborescence Problem. We present a branch-and-cut-and-bound approach taking advantage of the special structure at hand which performs well when compared to other approaches. Furthermore, using a suitable stopping criterion, we obtain approximations of provably excellent quality (in most cases actually optimal solutions). The test bed includes the real water distribution network from the Lausanne region, as well as carefully randomly generated realistic instances

Time-window of occurrence and vegetation cover preferences of Dartford and Sardinian Warblers after fire

Abstract Wildfires are the most extensive and severe disturbance affecting the shrublands where Sardinian and Dartford Warblers (Sylvia melanocephala and S. undata) abound. Estimating the long-term use of burned habitats by these species (i.e. their time-window of occurrence) is fundamental to understanding their regional distribution and to plan possible conservation measures for the nearthreatened Dartford Warbler. In this study, we describe the post-fire time-window of occurrence and cover preferences of the two warblers using an abundance dataset, gathered by point counts over 22 consecutive years, and a density dataset, resulting from territory mapping of four different plots for up to 8 years. Both datasets span before and after fire. The two species colonized burned areas as soon as the second year after fire. The Dartford Warbler showed its highest abundance between 4 and 9 years after fire an