The structure of problem-solving knowledge and the structure of organisations

This work presents a model of organisational problem solving able to account for the relationships between problem complexity, tasks decentralilzation and problem solving efficiency. Whenever problem solving requires the coordination of a multiplicity of interdependent elements, the varying degrees of decentralization of cognitive and operational tasks shape the solution which can be generated, tested and selected. Suboptimality and path-dependence are shown to be ubiquitous features of organisational problem solving. At the same time, the model allows a precise exploration of the possible trade-offs between decompostion patterns and search efficiency involved in different organisational architectures.-

The arrival of the new

In this work we present a number of urn models in which, contrary to standard Pólya urns, the number of competing alternatives is not given from the outset but may increase with the arrival of innovations. We begin by describing a variant of Pólya urns, first introduced by Fred Hoppe, in which balls of previously non-existing colors are added with some (declining) probability. We then propose new variants in which the probability of the arrival of new colors is itself subject to adaptive change depending on the success of past innovations and discuss applications to evolutionary models of technologies and industries. We numerically simulate different specifications of these urns with adaptively changing mutation rate and show that they can account for complex patterns of evolution in which periods of exploration and innovation are followed by periods in which the dynamics of the system is driven by selection among a stable set of alternatives.</p

Multi-Criteria Optimal Planning for Energy Policies in CLP

In the policy making process a number of disparate and diverse issues such as economic development, environmental aspects, as well as the social acceptance of the policy, need to be considered. A single person might not have all the required expertises, and decision support systems featuring optimization components can help to assess policies. Leveraging on previous work on Strategic Environmental Assessment, we developed a fully-fledged system that is able to provide optimal plans with respect to a given objective, to perform multi-objective optimization and provide sets of Pareto optimal plans, and to visually compare them. Each plan is environmentally assessed and its footprint is evaluated. The heart of the system is an application developed in a popular Constraint Logic Programming system on the Reals sort. It has been equipped with a web service module that can be queried through standard interfaces, and an intuitive graphic user interface.Comment: Accepted at ICLP2014 Conference as Technical Communication, due to appear in Theory and Practice of Logic Programming (TPLP

Soil Erosion Aspects in Agricultural Ecosystem

Agricultural activities have an important role in the primary sector of Italian economy. Within the present work, insert in a book dealing with the aspect related to soil erosion in agriculture, vineyard have been studied with the aim to analyze the effects caused by the intense cultivation practices, evaluating the annual soil loss and the management methodologies causing an increase or decrease of erosion phenomenon. The studies have been focused on the North-West Italy, in Monferrato area

The arrival of the new

In this work we present a number of urn models in which, contrary to standard Polya urns, the number of competing alternatives is not given from the outset but may increase with the arrival of innovations. We begin by describing a variant of Poya urns, first introduced by Fred Hoppe, in which balls of previously non-existing colors are added with some (declining) probability. We then propose new variants in which the probability of the arrival of new colors is itself subject to adaptive change depending on the success of past innovations and discuss applications to evolutionary models of technologies and industries. We numerically simulate different specifications of these urns with adaptively changing mutation rate and show that they can account for complex patterns of evolution in which periods of exploration and innovation are followed by periods in which the dynamics of the system is driven by selection among a stable set of alternatives

The arrival of the new

In this work we present a number of urn models in which, contrary to standard Polya urns, the number of competing alternatives is not given from the outset but may increase with the arrival of innovations. We begin by describing a variant of Polya urns, first introduced by Fred Hoppe, in which balls of previously non existing colours are added with some (declining) probability. We then propose new variants in which the probability of the arrival on new colours is itself subject to adaptive change depending on the success of past innovations. We numerically simulate different specifications of these urns with adaptively changing mutation rate and show that they can account for complex patterns of evolution in which periods of exploration with clusters of innovations are followed by periods in which the dynamics of the system is driven by selection among a stable set of alternatives

C1 anterior arch preservation in transnasal odontoidectomy using three-dimensional endoscope: A case report

BACKGROUND: The transoral ventral corridor is the most common approach used to reach the craniovertebral junction (CVJ). Over the last decade, many case reports have demonstrated the transnasal corridor to the odontoid peg represents a practicable route to remove the tip of the odontoid process. The biomechanical consequences of the traditional odontoidectomy led to the necessity of a cervical spine stabilization. Preserving the inferior portion of the C1 anterior arch should prevent instability. CASE DESCRIPTION: This is the first report in which the technique to remove the tip of the odontoid while preserving the C1 anterior arch is described by means of a three-dimensional (3D) endoscope. A 53-year-old man underwent a transnasal 3D endoscopic approach because of a complex CVJ malformation. The upper-medial portion of the C1 anterior arch was removed preserving its continuity, and the odontoidectomy was performed. After surgery, a dynamic X-ray scan showed no difference in CVJ motility in comparison with the preoperative one. CONCLUSIONS: The stereoscopic perception augmented the precision of the surgical gesture in the deep field. The importance of a 3D view relates to the depth of field, which a two-dimensional endoscopy cannot provide. This affects the preservation of the C1 anterior arch because of the presence of critical structures that are exposed to potential damage if not displayed

Pool Boiling Versus Surface Wettability Characteristics

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Start-up in microgravity and local thermodynamic states of a hybrid loop thermosyphon/pulsating heat pipe

A wickless passive two phase closed loop heat transfer device especially designed for a future implementation on the heat transfer host module of the International Space Station is tested in relevant environment on board a parabolic flight. The tube internal diameter (3 mm) is larger than the static capillary threshold evaluated in normal gravity for this working fluid (FC-72), leading the device to work as a loop thermosyphon on ground and in hyper-gravity conditions, and as a Pulsating Heat Pipe when micro-gravity occurs. Novel start up tests, where the heat load has been provided after the occurrence of microgravity, show that the 20 s microgravity period is enough for the device activation and, most important, that the device activation is purely thermally induced and not affected by the previous acceleration field. Two miniaturized pressure transducers and direct fluid temperature measurement via two micro-thermocouples, allow to provide a detailed insight on the fluid local thermodynamics states both in the evaporator and in the condenser zone during microgravity. It is shown that the two-phase fluid close to the evaporator and the condenser is subjected to several degrees (up to 5 K) of superheating or subcooling. The level of subcooling seems to increase with the heat input level both in terms of temperature difference and in terms of percentage time with respect to the whole microgravity period