On the Polytope Escape Problem for Continuous Linear Dynamical Systems

The Polyhedral Escape Problem for continuous linear dynamical systems consists of deciding, given an affine function $f: \mathbb{R}^{d} \rightarrow \mathbb{R}^{d}$ and a convex polyhedron $\mathcal{P} \subseteq \mathbb{R}^{d}$, whether, for some initial point $\boldsymbol{x}_{0}$ in $\mathcal{P}$, the trajectory of the unique solution to the differential equation $\dot{\boldsymbol{x}}(t)=f(\boldsymbol{x}(t))$, $\boldsymbol{x}(0)=\boldsymbol{x}_{0}$, is entirely contained in $\mathcal{P}$. We show that this problem is decidable, by reducing it in polynomial time to the decision version of linear programming with real algebraic coefficients, thus placing it in $\exists \mathbb{R}$, which lies between NP and PSPACE. Our algorithm makes use of spectral techniques and relies among others on tools from Diophantine approximation.Comment: Accepted to HSCC 201

On Termination of Integer Linear Loops

A fundamental problem in program verification concerns the termination of simple linear loops of the form x := u ; while Bx >= b do {x := Ax + a} where x is a vector of variables, u, a, and c are integer vectors, and A and B are integer matrices. Assuming the matrix A is diagonalisable, we give a decision procedure for the problem of whether, for all initial integer vectors u, such a loop terminates. The correctness of our algorithm relies on sophisticated tools from algebraic and analytic number theory, Diophantine geometry, and real algebraic geometry. To the best of our knowledge, this is the first substantial advance on a 10-year-old open problem of Tiwari (2004) and Braverman (2006).Comment: Accepted to SODA1

Release profile of ibuprofen in β-cyclodextrin complexes from two different solid dosage forms

The objective of this work was to develop solid dosage forms using powders containing inclusion complexes (ibuprofen with β-cyclodextrin) which were used to produce tablets (direct compression without additional excipients) and pellets (extrusion/spheronization) from wet mass containing 40% (w/w) of microcrystalline cellulose. The pellets also demonstrated that during preparation of the wet mass, the inclusion process occurred in a same yield that when pre-complexation was used. The particles characteristics were evaluated after being obtained through different complexation methods. The results showed that the tensile strength and profile dissolution were as expected for both dosage forms. Tablets containing inclusion complexes showed higher solubility when compared with a reference formulation and with two commercial formulations. The ibuprofen released from the two pellets formulations didn’t show relevant differences between them. The drug released was analyzed considering different dissolution parameters. The advantages of these new methodologies can be summarized as: (a) tablets were produced at a lower cost for the total process; and (b) in the pellet´s preparation there was no need of the previous complexation method resulting in a decrease in time and energy required

Business Model Generation: A handbook for visionaries, game changers and challengers

The book entitled “Business Model Generation: A Handbook for visionaries, game changers and challengers” though written by Osterwalder and Pigneur (2010) was also co-created by 470 practitioners from 45 countries. The book is thus a good example of how a global creative collaboration effort can contribute positively to the business and management literature and subsequently to the advancement of society. The book "Business Model Generation" has both narrative and visual detail. Before proceeding to do an in-depth review of “Business Model Generation” we first looked at other publications by the authors which led up to the book

Distributed LQG control of a water delivery canal with feedforward from measured consumptions

This work addresses the design of distributed LQG controllers for water delivery canals that include feedforward from local farmer water consumptions. The proposed architecture consists of a network of local control agents, each connected to one of the canal pools and sharing information with their neighbors in order to act in a coordinated way. In order to improve performance, the measurement of the outflows from each pool is used as a feedforward signal. Although the feedforward action is local. It propagates due to the coordinates procedure. The paper presents the distributed LQG algorithm with feedforward and experimental results in a large scale pilot water delivery canal

Producing innovation: Comments on Lee and Yu (2010)

The purpose of the article being reviewed (Lee and Yu, 2010), a survey by questionnaire with 182 valid responses, is to analyze “how different relationship styles of employees in the hi-tech industry influence innovation performance” and indeed its conclusions are that “the relationship style of an organization has a significant positive effect on innovation performance”. We see Lee and Yu (2010) as being similar to another highly cited article by Morgan and Hunt in so far as both articles are about relationships, cooperation and trust

The economics of LBOs: evidence from the syndicated loan market

This paper surveys extant literature on Leveraged Buy-Outs (LBOs). In addition to describing the economic motivation for the use of LBOs, this paper provides details on LBO characteristics and players, it presents the recent trends of the market, and provides statistics in relation to syndicated loans extended to LBOs worldwide in the 2000-2020 period. LBOs create economic value by reducing agency problems, improving operating performance, increasing interest tax shields, reducing transaction costs, and allowing for takeover defenses. However, LBOs also have drawbacks, namely: high complexity, off-balance sheet treatment, asymmetric information problems, expropriation of nonequity stakeholders, and increased financial distress. Statistical analysis shows that loan contractual characteristics differ significantly in the pre- versus the crisis period, and both loan spread and major pricing factors differ significantly for deals closed in the U.S. vis-à-vis Europe. In addition, loans to LBOs arranged for U.S. borrowers have higher spreads and upfront fees and have higher loan size to deal size ratios when compared with loans arranged for borrowers located in Europe. On the contrary, loans closed in the U.S. have a much shorter average maturity and are much less likely to be subject to currency risk and to be closed as term loans.info:eu-repo/semantics/publishedVersio