Number Theory Revealed: An Introduction

It is a review of the book "Number theory revealed: An introduction", by A. Granville

Data-driven and Model-based Verification: a Bayesian Identification Approach

This work develops a measurement-driven and model-based formal verification approach, applicable to systems with partly unknown dynamics. We provide a principled method, grounded on reachability analysis and on Bayesian inference, to compute the confidence that a physical system driven by external inputs and accessed under noisy measurements, verifies a temporal logic property. A case study is discussed, where we investigate the bounded- and unbounded-time safety of a partly unknown linear time invariant system

Observer-based correct-by-design controller synthesis

Current state-of-the-art correct-by-design controllers are designed for full-state measurable systems. This work first extends the applicability of correct-by-design controllers to partially observable LTI systems. Leveraging 2nd order bounds we give a design method that has a quantifiable robustness to probabilistic disturbances on state transitions and on output measurements. In a case study from smart buildings we evaluate the new output-based correct-by-design controller on a physical system with limited sensor information

Dynamics in Several Complex Variables

In this chapter we shall describe the dynamics of holomorphic self-maps of taut manifolds, and in particular the dynamics of holomorphic self-maps of convex and strongly pseudoconvex domains. A main tool in this exploration will be provided by the Kobayashi distance

Baryonic acoustic oscillations simulations for the Large Synoptic Survey Telescope (LSST)

The baryonic acoustic oscillations are features in the spatial distribution of the galaxies which, if observed at different epochs, probe the nature of the dark energy. In order to be able to measure the parameters of the dark energy equation of state to high precision, a huge sample of galaxies has to be used. The Large Synoptic Survey Telescope will survey the optical sky with 6 filters from 300nm and 1100nm, such that a catalog of galaxies with photometric redshifts will be available for dark energy studies. In this article, we will give a rough estimate of the impact of the photometric redshift uncertainties on the computation of the dark energy parameter through the reconstruction of the BAO scale from a simulated photometric catalog.Comment: 4 pages, 2 figures, 10th Rencontres de Blois proceedin

Out of the archaeologist's desk drawer: communicating archaeological data online

During archaeological field work a huge amount of data is collected, processed and elaborated for further studies and scientific publications. However, access and communication of linked data; associated tools for interrogation, analysis and sharing are often limited at the first stage of the archaeological research, mainly due to issues related to IPR. Information is often released months if not years after the fieldwork. Nowadays great deal of archaeological data is 'born digital' in the field or lab. This means databases, pictures and 3D models of finds and excavation contexts could be available for public communication and sharing. Researchers usually restrict access to their data to a small group of people. It follows that data sharing is not so widespread among archaeologists, and dissemination of research is still mostly based on traditional pre-digital means like scientific papers, journal articles and books. This project has implemented a web approach for sharing and communication purposes, exploiting mainly open source technologies which allow a high level of interactivity. The case study presented is the newly Mithraeum excavated in Ostia Antica archaeological site in the framework of the Ostia Marina Project

How to Test for Diagonalizability: The Discretized PT-Invariant Square-Well Potential

Given a non-hermitean matrix M, the structure of its minimal polynomial encodes whether M is diagonalizable or not. This note will explain how to determine the minimal polynomial of a matrix without going through its characteristic polynomial. The approach is applied to a quantum mechanical particle moving in a square well under the influence of a piece-wise constant PT-symmetric potential. Upon discretizing the configuration space, the system is decribed by a matrix of dimension three. It turns out not to be diagonalizable for a critical strength of the interaction, also indicated by the transition of two real into a pair of complex energy eigenvalues. The systems develops a three-fold degenerate eigenvalue, and two of the three eigenfunctions disappear at this exceptional point, giving a difference between the algebraic and geometric multiplicity of the eigenvalue equal to two.Comment: 5 page

The optimal shipment size and truck size choice - the allocation of trucks across hauls

There has been a growing interest in understanding how firms allocate their trucks across hauls, and how this allocation changes under various economic environments. This study investigates how variations in route/haul, carrier and vehicle characteristics affect the optimal vehicle size choice and the associated choice of shipment size. We show that the two choices are derived from the same optimization problem. There can be a continuum of shipment sizes, but decision-makers in freight transport have to choose from a limited number of vehicle alternatives. Therefore, we use a discrete–continuous econometric model where shipment size is modeled as a continuous variable, and vehicle size/type choice as a discrete variable. The results indicate that when faced with higher demand, and during longer trips firms are more likely to use heavier vehicles and ship in larger quantities which suggest that firms are realizing economies of scale and economies of distance. The study also discusses the effect of vehicle operating cost on the vehicle selection process and its policy implications

Efficient photosynthesis of carbon monoxide from CO2 using perovskite photovoltaics

Artificial photosynthesis, mimicking nature in its efforts to store solar energy, has received considerable attention from the research community. Most of these attempts target the production of H2 as a fuel and our group recently demonstrated solar-to-hydrogen conversion at 12.3% efficiency. Here, in an effort to take this approach closer to real photosynthesis, which is based on the conversion of CO2, we demonstrate the efficient reduction of CO2 to carbon monoxide driven solely by simulated sunlight using water as the electron source. Employing series-connected perovskite photovoltaics and high-performance catalyst electrodes, we reach a solar-to-CO efficiency exceeding 6.5%, which represents a new benchmark in sunlight-driven CO2 conversion. Considering hydrogen as a secondary product, an efficiency exceeding 7% is observed. Furthermore, this study represents one of the first demonstrations of extended, stable operation of perovskite photovoltaics, whose large open-circuit voltage is shown to be particularly suited for this process

Designing and Manufacturing of Bamboo Processing Machine

This document describes about designing and manufacturing of bamboo processing machine having three functions, namely; splitting, grinding and sanding bamboo surfaces. It helps to avoid a tedious and time taking manual bamboo processing. Three people can work at the same time when a need arise. It is designed considering safety factors and ergonomic considerations. The machine is robust in design having low sound, and good aesthetic so as to look attractive and durable while giving service. Designing and fabricating such type of machine is important so as to save money and it avoids from buying individual machine. For the purpose of convenience, focusing on the need assessment of the project, developers are using exploratory research method. Exploratory research made by conducting focus group interviews to get detail information. Developers used four data gathering techniques (tools), namely; oral questions, direct observation, document analysis and questionnaires (closed and open questionnaires) to understand current problems of bamboo processing activities and for the need of this machine. After the quantitative and qualitative data are gathered from those sources developersreached at conclusion to designed and manufactured bamboo processing machine as a solution to facilitate bamboo products. The findings indicate that, there is lack of bamboo processing machine and having high demand of it. In general, according to the newly designed and manufactured bamboo processing machine, it can perform manual splitting, grinding bamboo knots and sanding bamboo surfaces. For the future it can create job opportunity to the society