An ontological approach to the construction of problem-solving models

Our ongoing work aims at defining an ontology-centered approach for building expertise models for the CommonKADS methodology. This approach (which we have named "OntoKADS") is founded on a core problem-solving ontology which distinguishes between two conceptualization levels: at an object level, a set of concepts enable us to define classes of problem-solving situations, and at a meta level, a set of meta-concepts represent modeling primitives. In this article, our presentation of OntoKADS will focus on the core ontology and, in particular, on roles - the primitive situated at the interface between domain knowledge and reasoning, and whose ontological status is still much debated. We first propose a coherent, global, ontological framework which enables us to account for this primitive. We then show how this novel characterization of the primitive allows definition of new rules for the construction of expertise models

Analyse numérique et réduction de réseaux

29 pagesNational audienceL'algorithmique des réseaux euclidiens est un outil fréquemment utilisé en informatique et en mathématiques. Elle repose essentiellement sur la réduction LLL qu'il est donc important de rendre aussi efficace que possible. Une approche initiée par Schnorr consiste à effectuer des calculs approchés pour estimer les orthogonalisations de Gram-Schmidt sous-jacentes. Sans approximations, ces calculs dominent le coût de la réduction. Récemment, des outils classiques d'analyse numérique ont été revisités et améliorés, pour exploiter plus systématiquement l'idée de Schnorr et réduire les coûts. Nous décrivons ces développements, notamment comment l'algorithmique en nombres flottants peut être introduite à plusieurs niveaux dans la réduction

Ultrasonic velocity survey in Callovo-Oxfordian argillaceous rock during shaft excavation

International audienceThe excavation of a deep underground structure induces a stress field redistribution that could create an excavation-damaged zone (EDZ). The study of the EDZ is important in the framework of nuclear waste storage, where such EDZ could constitute a preferential pathway of stored material towards the biosphere. Analysis of ultrasonic wave propagation across the rock media around the excavation is one technique that can be used to characterize such zones. This method has been applied in the Meuse/Haute-Marne Underground Research Laboratory (URL) in France to characterize the initialization and evolution of damage around the URL access shaft. To achieve this, a device comprising 21 ultrasonic sensors was spread out at different distances from the shaft wall, at depths between -465 and -475 m. A transversely isotropic model enabled the measured experimental velocities on each ray path during shaft excavation to be integrated. The results highlighted the initialization and extension of the damage as the shaft front proceeded. They also showed a polarization of the velocity field and an oscillation of the transversal isotropy with a preferential orientation of the stress release and the microcracking. Monitoring of the velocity field also highlighted some significantly different behaviour linked to the complex mechanical behaviour of the argillaceous rock

Tools for an integrated systems approach to sustainable port city planning

Large port cities like Shanghai, Amsterdam and Rio de Janeiro are key cogwheels in international logistics and transport networks but also serve as showcases for the rest of the world; as such, they constitute strategic assets for the host country´s economy and international influence. Historically, a city and its port often developed independently, through sometimes contradictory or even confrontational policies. Today, the growing number of usage disputes over increasingly coveted coastal areas is prompting local managers to incorporate urban and port-related issues in overarching planning programs. In particular, planning of the sea front and the buffer zone between the port and the city must contribute decisively to the deployment of more effective, cleaner transport services for the port city as a whole. In general, one of the key global challenges for planners and decision-makers consists in integrating sustainable development goals (environmental and social components, as well as the stimulation of industrial competitiveness) into urban planning. In this context the PHEBUS research group has initiated an international program of research to develop innovative methods and tools that can help territorial stakeholders to design, evaluate, compare and ultimately choose development scenarios for the future of their port cities. The main themes are addressed via a multidisciplinary systems approach on the scale of a coastal urban area with an industrial and port complex. In particular, the themes include sea front planning, the city-port interface, energy optimization (e.g. the introduction and sharing of renewable energies), risk resilience, climate change and multimodal, clean transport

Development of CMOS Pixel Sensors fully adapted to the ILD Vertex Detector Requirements

CMOS Pixel Sensors are making steady progress towards the specifications of the ILD vertex detector. Recent developments are summarised, which show that these devices are close to comply with all major requirements, in particular the read-out speed needed to cope with the beam related background. This achievement is grounded on the double- sided ladder concept, which allows combining signals generated by a single particle in two different sensors, one devoted to spatial resolution and the other to time stamp, both assembled on the same mechanical support. The status of the development is overviewed as well as the plans to finalise it using an advanced CMOS process.Comment: 2011 International Workshop on Future Linear Colliders (LCWS11), Granada, Spain, 26-30 September 201

Surgical management of abdominal and retroperitoneal Castleman's disease

BACKGROUND: Abdominal and retroperitoneal Castleman's disease could present either as a localized disease or as a systemic disease. Castleman's disease is a lymphoid hyperplasia related to human Herpes virus type 8, which could have an aggressive behavior, similar to that of malignant lymphoid neoplasm mainly with the systemic type, or a benign one in its localized form. METHODS: The authors report two cases of localized Castleman's disease in the retroperitoneal space and review the current and recent progress in the knowledge of this atypical disease. CASES PRESENTATION: The two patients were young healthy women presenting with a hyper vascular peri-renal mass suggestive of malignant tumor. Both have been resected in-toto. One of them had an extensive resection with nephrectomy, while the second had a kidney preserving surgery. Pathological examination revealed localized Castleman's disease and surgical margins were free of disease. Postoperative course was uneventful, and after more than 5-years of follow-up no recurrences have been observed. CONCLUSION: Localized Castleman's disease should be considered when facing a solid hypervascular abdominal or retroperitoneal mass. A better knowledge of this disorder and its characteristic would help surgeon to avoid unnecessarily extensive resection for this benign disorder when dealing with abdominal or retroperitoneal tumors. Surgical resection is curative for the localized form, when complete, while splenectomy could be indicated for the systemic form

Reducing Cost of Surgery by Avoiding Complications: the Model of Robotic Roux-en-Y Gastric Bypass

Background: Robotic surgery is a complex technology offering technical advantages over conventional methods. Still, clinical outcomes and financial issues have been subjects of debate. Several studies have demonstrated higher costs for robotic surgery when compared to laparoscopy or open surgery. However, other studies showed fewer costly anastomotic complications after robotic Roux-en-Y gastric bypass (RYGBP) when compared to laparoscopy. Methods: We collected data for our gastric bypass patients who underwent open, laparoscopic, or robotic surgery from June 1997 to July 2010. Demographic data, BMI, complications, mortality, intensive care unit stay, hospitalization, and operating room (OR) costs were analyzed and a cost projection completed. Sensitivity analyses were performed for varied leak rates during laparoscopy, number of robotic cases per month, number of additional staplers during robotic surgery, and varied OR times for robotic cases. Results: Nine-hundred ninety patients underwent gastric bypass surgery at the University Hospital Geneva from June 1997 to July 2010. There were 524 open, 323 laparoscopic, and 143 robotic cases. Significantly fewer anastomotic complications occurred after open and robotic RYGBP when compared to laparoscopy. OR material costs were slightly less for robotic surgery (USD 5,427) than for laparoscopy (USD 5,494), but more than for the open procedure (USD 2,251). Overall, robotic gastric bypass (USD 19,363) was cheaper when compared to laparoscopy (USD 21,697) and open surgery (USD 23,000). Conclusions: Robotic RYGBP can be cost effective due to balancing greater robotic overhead costs with the savings associated with avoiding stapler use and costly anastomotic complication