A Generalized Markov-Chain Modelling Approach to (1,λ)(1,\lambda)-ES Linear Optimization: Technical Report

Several recent publications investigated Markov-chain modelling of linear optimization by a $(1,\lambda)$-ES, considering both unconstrained and linearly constrained optimization, and both constant and varying step size. All of them assume normality of the involved random steps, and while this is consistent with a black-box scenario, information on the function to be optimized (e.g. separability) may be exploited by the use of another distribution. The objective of our contribution is to complement previous studies realized with normal steps, and to give sufficient conditions on the distribution of the random steps for the success of a constant step-size $(1,\lambda)$-ES on the simple problem of a linear function with a linear constraint. The decomposition of a multidimensional distribution into its marginals and the copula combining them is applied to the new distributional assumptions, particular attention being paid to distributions with Archimedean copulas

Hierarchical Archimedean Copulas for MATLAB and Octave: The HACopula Toolbox

To extend the current implementation of copulas in MATLAB to non-elliptical distributions in arbitrary dimensions enabling for asymmetries in the tails, the toolbox HACopula provides functionality for modeling with hierarchical (or nested) Archimedean copulas. This includes their representation as MATLAB objects, evaluation, sampling, estimation and goodness-of-fit testing, as well as tools for their visual representation or computation of corresponding matrices of Kendall's tau and tail dependence coefficients. These are first presented in a quick-and-simple manner and then elaborated in more detail to show the full capability of HACopula. As an example, sampling, estimation and goodness-of-fit of a 100-dimensional hierarchical Archimedean copula is presented, including a speed up of its computationally most demanding part. The toolbox is also compatible with Octave, where no support for copulas in more than two dimensions is currently provided

Smart Design of Cz-Ge Crystal Growth Furnace and Process

The aim of this study was to evaluate the potential of the machine learning technique of decision trees to understand the relationships among furnace design, process parameters, crystal quality, and yield in the case of the Czochralski growth of germanium. The ultimate goal was to provide the range of optimal values of 13 input parameters and the ranking of their importance in relation to their impact on three output parameters relevant to process economy and crystal quality. Training data were provided by CFD modelling. The variety of data was ensured by the Design of Experiments method. The results showed that the process parameters, particularly the pulling rate, had a substantially greater impact on the crystal quality and yield than the design parameters of the furnace hot zone. Of the latter, only the crucible size, the axial position of the side heater, and the material properties of the radiation shield were relevant

Guidelines for Perioperative Care for Emergency Laparotomy Enhanced Recovery After Surgery (ERAS) Society Recommendations: Part 1—Preoperative: Diagnosis, Rapid Assessment and Optimization

BackgroundEnhanced Recovery After Surgery (ERAS) protocols reduce length of stay, complications and costs fora large number of elective surgical procedures. A similar, structured approach appears to improve outcomes, including mortality, for patients undergoing high-risk emergency general surgery, and specifically emergency laparotomy. These are the first consensus guidelines for optimal care of these patients using an ERAS approach.MethodsExperts in aspects of management of the high-risk and emergency general surgical patient were invited to contribute by the International ERAS Society. Pubmed, Cochrane, Embase, and MEDLINE database searches on English language publications were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized controlled trials, systematic reviews, meta-analyses and large cohort studies, and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on non-emergency patients when appropriate. The Delphi method was used to validate final recommendations. The guideline has been divided into two parts: Part 1—Preoperative Care and Part 2—Intraoperative and Postoperative management. This paper provides guidelines for Part 1.ResultsTwelve components of preoperative care were considered. Consensus was reached after three rounds.ConclusionsThese guidelines are based on the best available evidence for an ERAS approach to patients undergoing emergency laparotomy. Initial management is particularly important for patients with sepsis and physiological derangement. These guidelines should be used to improve outcomes for these high-risk patients

CORBA security services for health information systems

The structure of healthcare systems in developed countries is changing to ‘shared care’, enforced by economic constraints and caused by a change in the basic conditions of care. That development results in co-operative health information systems across the boundaries of organisational, technological, and policy domains. Increasingly, these distributed and, as far as their domains are concerned, heterogeneous systems are based on middleware approaches, such as CORBA. Regarding the sensitivity of personal and medical data, such open, distributed, and heterogeneous health information systems require a high level of data protection and data security, both with respect to patient information and with respect to users. This paper, relying on experience gained through our activities in CORBAmed, describes the possibilities the CORBA middleware provides to achieve application and communication security. On the background of the overall CORBA architecture, it outlines the different security services previewed in the adopted CORBA specifications which are discussed in the context of the security requirements of healthcare information systems. Security services required in the healthcare domain but not available at the moment are mentioned. A solution is proposed, which on the one hand allows to make use of the available CORBA security services and additional ones, on the other hand remains open to other middleware approaches, such as DHE or HL7