An Inverse Method for Policy-Iteration Based Algorithms

We present an extension of two policy-iteration based algorithms on weighted graphs (viz., Markov Decision Problems and Max-Plus Algebras). This extension allows us to solve the following inverse problem: considering the weights of the graph to be unknown constants or parameters, we suppose that a reference instantiation of those weights is given, and we aim at computing a constraint on the parameters under which an optimal policy for the reference instantiation is still optimal. The original algorithm is thus guaranteed to behave well around the reference instantiation, which provides us with some criteria of robustness. We present an application of both methods to simple examples. A prototype implementation has been done

The level set method for the two-sided eigenproblem

We consider the max-plus analogue of the eigenproblem for matrix pencils Ax=lambda Bx. We show that the spectrum of (A,B) (i.e., the set of possible values of lambda), which is a finite union of intervals, can be computed in pseudo-polynomial number of operations, by a (pseudo-polynomial) number of calls to an oracle that computes the value of a mean payoff game. The proof relies on the introduction of a spectral function, which we interpret in terms of the least Chebyshev distance between Ax and lambda Bx. The spectrum is obtained as the zero level set of this function.Comment: 34 pages, 4 figures. Changes with respect to the previous version: we explain relation to mean-payoff games and discrete event systems, and show that the reconstruction of spectrum is pseudopolynomia

Current progress on the numerical simulation of detached flows around airplanes

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Diastereo- and Enantioselective Pd(II)-Catalyzed Additions of 2-Alkylazaarenes to N-Boc Imines and Nitroalkenes

A chiral Pd(II)–bis(oxazoline) complex was found to be highly effective in promoting the first direct diastereo- and enantioselective addition of alkylazaarenes to N-Boc aldimines and nitroalkenes under mild conditions. Deprotection of Boc-protected products proceeded readily to provide amines in high yields

Long-term outcomes of clinical complete responders after neoadjuvant treatment for rectal cancer in the International Watch & Wait Database (IWWD): an international multicentre registry study

Background: The strategy of watch and wait (W&W) in patients with rectal cancer who achieve a complete clinical response (cCR) after neoadjuvant therapy is new and offers an opportunity for patients to avoid major resection surgery. However, evidence is based on small-to-moderate sized series from specialist centres. The International Watch & Wait Database (IWWD) aims to describe the outcome of the W&W strategy in a large-scale registry of pooled individual patient data. We report the results of a descriptive analysis after inclusion of more than 1000 patients in the registry. Methods: Participating centres entered data in the registry through an online, highly secured, and encrypted research data server. Data included baseline characteristics, neoadjuvant therapy, imaging protocols, incidence of local regrowth and distant metastasis, and survival status. All patients with rectal cancer in whom the standard of care (total mesorectal excision surgery) was omitted after neoadjuvant therapy were eligible to be included in the IWWD. For the present analysis, we only selected patients with no signs of residual tumour at reassessment (a cCR). We analysed the proportion of patients with local regrowth, proportion of patients with distant metastases, 5-year overall survival, and 5-year disease-specific survival. Findings: Between April 14, 2015, and June 30, 2017, we identified 1009 patients who received neoadjuvant treatment and were managed by W&W in the database from 47 participating institutes (15 countries). We included 880 (87%) patients with a cCR. Median follow-up time was 3·3 years (95% CI 3·1–3·6). The 2-year cumulative incidence of local regrowth was 25·2% (95% CI 22·2–28·5%), 88% of all local regrowth was diagnosed in the first 2 years, and 97% of local regrowth was located in the bowel wall. Distant metastasis were diagnosed in 71 (8%) of 880 patients. 5-year overall survival was 85% (95% CI 80·9–87·7%), and 5-year disease-specific survival was 94% (91–96%). Interpretation: This dataset has the largest series of patients with rectal cancer treated with a W&W approach, consisting of approximately 50% data from previous cohort series and 50% unpublished data. Local regrowth occurs mostly in the first 2 years and in the bowel wall, emphasising the importance of endoscopic surveillance to ensure the option of deferred curative surgery. Local unsalvageable disease after W&W was rare. Funding: European Registration of Cancer Care financed by European Society of Surgical Oncology, Champalimaud Foundation Lisbon, Bas Mulder Award granted by the Alpe d'Huzes Foundation and Dutch Cancer Society, and European Research Council Advanced Grant

Contribution à la conception d'un émetteur-récepteur pour microcapteurs autonomes

Survey on wireless microsensor networks highlights the main constraint of energy autonomy. In fact, these autonomous and communicating microcomponents named network nodes are scattered into few or not open environment. The goal of our work is to propose a transceiver design method adapted to microsensor networks. After a demonstration of predominant part of RF into the mean power consumption of a microsensor node, we developed three new simulation tools which correspond to different level of transceiver modelling. Their use and obtained simulation results demonstrate the relation between transceiver specifications and performances with power consumption. The association of these tools was used to propose a new design method under power consumption constraint. Finally, we designed, produced and tested a 868 MHz Low Noise Amplifier which presents interesting power consumption characteristics.L'étude des réseaux de microcapteurs sans fil met clairement en évidence la contrainte principale de l'autonomie en énergie. En effet, ces microcomposants autonomes et communicants appelés aussi noeuds du réseau sont dispersés dans des lieux parfois peu ou pas accessibles. L'objectif de notre travail est de proposer une méthode de conception d'un émetteur-récepteur adapté à ce type de réseaux. Partant d'une modélisation au niveau système mettant en relief la part prépondérante du module radiofréquence sur la consommation moyenne d'un noeud, nous avons développé trois nouveaux outils de conception correspondant à différents niveaux de modélisation de la chaine de communication. Leur utilisation conjointe et les résultats de simulations obtenus nous offrent la possibilité de mettre en relation les spécifications et les performances d'un module radiofréquence avec la consommation. L'association de ces outils dans une méthode de conception itérative nous a permis de dimensionner une chaine de communication en fonction d'une contrainte de consommation. Finalement, nous avons conçu, fabriqué et testé, un amplificateur faible bruit (LNA ou Low Noise Amplifier) à 868 MHz qui présente des caractéristiques très intéressantes en termes de consommation

Programme forest : pathologie du peuplier : test Marssonina 1989

The objective of this test developed in May 1989 was to verify the sensitivity to Marssonina brunnea of "suspected" clones, that is, clones that were suspected in previous tests under high inocunum pressures. Unfortunately, the climatic conditions of 1989 to 1991 were not favorable to the continuous development of the disease. Measurements were made only from September 18 to 24, 1991 (the results are shown in this article). They seem to indicate differences with observations made in other countries (the Netherlands, Italy). / Ce test mis en place en mai 1989 avait pour objectif de vérifier la sensibilité au Marssonina brunnea des clones qui s'étaient avérés "douteux" dans les tests précédents sous des pressions d'inocumum élevés. Malheureusement, les conditions climatiques des années 1989 à 1991 ont toujours été défavorables au développement continu de la maladie. Le dispositif n'a donc été noté que du 18 au 24 septembre 1991 (les résultats sont présentés dans cette note). Il se confirme des discordances entre les résultats de ce test et les observations réalisées dans l'autres pays (Pays-Bas, Italie)

Intensification de la production de graines améliorées dans les vergers à graines français

The fact that seed-orchards developed by the French government are now in full production, leads to experiment different techniques aimed at intensifying production. Supply of ammonium sulfate to Pinus pinaster has led to a 50% increase in the number of female flowers and has had a positive effect on pollen production. Similarly, NPK fertilizers supplied to Pseudotsuga menziesii have resulted in an increase in the number of male flowers and fruit, the number of cones was 70% higher than the mean of untreated plants. Hormonal treatments applied to Pseudotsuga menziesii and Picea abies gave good results. However, they were considered insufficient to justify big scale use. Tests aimed at improving their efficiency are currently being conducted. On the other hand, problems encountered in the hybridization of Larix decidua and Larix leptolepis, have led the Cemagref to design an original technique to harvest pollen mechanically. This retained principle does not affect pollen quality, the oldest seeds harvested have retained their viability. A prototype inspired from modern coating techniques by electrostatic powdering is being developed. / L'entrée en production des vergers à graines établis par l'Etat français, conduit à expérimenter différentes techniques propres à intensifier la production. Chez Pinus Pinaster, l'apport de sulfate d'ammoniaque a entraîné un accroissement de 50 % du nombre de fleurs femelles et a eu une action positive sur la production de pollen. De même, des fertilisations N P K ont permis d'intensifier la floraison mâle ainsi que la fructification de Pseudotsuga menziesii, la production de cones des plants traités étant de moyenne supérieure de 70 % à celle des témoins. Les traitements hormonaux, testés sur Pseudotsuga menziesii et Picea abies se sont également révélés extrêmement bénéfiques. Ils ont toutefois engendré une réponse insuffisante pour justifier leur utilisation à grande échelle. Des essais destinés à améliorer leur efficacité sont en cours actuellement. D'autre part, les difficultés rencontrées dans le domaine de l'hybridation de Larix decidua et Larix leptolepis ont amené le CEMAGREF à imaginer une technique originale de récolte mécanisée du pollen. Le principe retenu n'altère pas la qualité du pollen, les plus anciennes récoltes ayant gardé une viabilité, un prototype, qui s'inspire des techniques modernes de revêtement par poudrage électrostatique, est en cours de mise au point