Search results for "Constructive"
showing 10 items of 301 documents
Preputial reconstruction in hypospadias repair
2017
Summary Objective In principle, the prepuce can be reconstructed during hypospadias repair, but the procedure has not gained wide acceptance and preputial reconstruction (PR) is surrounded by several controversies. Material and methods A review is provided of the technique for PR, how PR combines with the other steps of hypospadias repair, the risks of complications related to the urethroplasty and specific to PR, and the results of PR with particular regard to the relevance for the patient and his family. Results PR can be important for patients requiring hypospadias repair and their parents. It can be performed in almost all patients with distal hypospadias except perhaps those with the m…
The Boundless World of Cranioplasty: A Multicenter Retrospective Study and Therapeutic Flow-Chart Patient-Specific Based.
2021
Background Cranioplasty is both a functional and aesthetical therapeutic option. In the clinical scenario every cranioplasty's material is potentially qualified to achieve the goal of calvarian reconstruction but there is a lack of agreement about the optimum choice, especially between the heterologous ones. The choice of cranioplasty widely depends on surgeon's personal preferences. In this retrospective multicentric study a comparative analysis of hydroxyapatite or titanium cranioplasties was carried on analyzing the main factors considered by the surgeon to choose a material rather than another one. Our results and data were compared with those reported in the scientific literature and a…
SARS-CoV-2 infection and venous thromboembolism after surgery: an international prospective cohort study
2021
SARS-CoV-2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri-operative or prior SARS-CoV-2 were at further increased risk of venous thromboembolism. We conducted a planned sub-study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 da…
A GRASP algorithm for constrained two-dimensional non-guillotine cutting problems
2005
This paper presents a greedy randomized adaptive search procedure (GRASP) for the constrained two-dimensional non-guillotine cutting problem, the problem of cutting the rectangular pieces from a large rectangle so as to maximize the value of the pieces cut. We investigate several strategies for the constructive and improvement phases and several choices for critical search parameters. We perform extensive computational experiments with well-known instances previously reported, first to select the best alternatives and then to compare the efficiency of our algorithm with other procedures.
Tabu search for a multi-objective routing problem
2006
Multi-objective optimization problems deal with the presence of different conflicting objectives. Given that it is not possible to obtain a single solution by optimizing all the objectives simultaneously, a common way to face these problems is to obtain a set of efficient solutions called the non-dominated frontier. In this paper, we address the problem of routing school buses with two objectives: minimize the number of buses, and minimize the longest time a student would have to stay in the bus. The trade-off in this problem is between service level, which is represented by the maximum route length, and operational cost, which is represented by the number of buses in the solution. We prese…
Research methods in business: Quantitative and qualitative comparative analysis
2020
[EN] Research in the social sciences is built on either quantitative or qualitative analysis, depending on the research context. Using both quantitative and qualitative analyses in the same study presents major obstacles. In the real business world, empirical studies could benefit from using multiple research methodologies. Thus, this editorial presents an overview of the literature on quantitative and qualitative research methods in business research to clarify some key issues on the subject. The following section introduces the papers included in the special issue on "Research Methods in Business: Quantitative and Qualitative Comparative Analysis" and highlights several novel ideas, emerg…
A study on stress distribution to cement layer and root dentin for post and cores made of CAD/CAM materials with different elasticity modulus in the …
2019
Background To evaluate the stress distribution in a maxillary central incisor with different post and cores made of six CAD/CAM materials with different elastic modulus in the absence of ferrule using the finite element analysis. Material and methods A three-dimensional endodontically treated maxillary central incisor restored with an all-ceramic crown was modelled in Rhinoceros (5.0 SR8, McNeel). The geometries were analyzed in ANSYS 17.2 (ANSYS Inc.) considering isotropic, homogeneous, linearly elastic materials with perfectly bonded contacts. The elastic moduli (E) of the post-and-cores defined the groups to be compared: nanoceramic resin (E=12.8GPa); composite resin (E=16GPa); hybrid ce…
Matheuristics for the irregular bin packing problem with free rotations
2017
[EN] We present a number of variants of a constructive algorithm able to solve a wide variety of variants of the Two-Dimensional Irregular Bin Packing Problem (2DIBPP). The aim of the 2DIBPP is to pack a set of irregular pieces, which may have concavities, into stock sheets (bins) with fixed dimensions in such a way that the utilization is maximized. This problem is inspired by a real application from a ceramic company in Spain. In addition, this problem arises in other industries such as the garment industry or ship building. The constructive procedure presented in this paper allows both free orientation for the pieces, as in the case of the ceramic industry, or a finite set of orientation…
The continuous Berth Allocation Problem in a container terminal with multiple quays
2015
We propose an integer linear model for the case of BAP with multiple quays.We design several constructive procedures and propose a large set of priority rules.We design a genetic algorithm, using the solutions obtained by the priority rules.For BAP with one quay, our genetic algorithm outperforms the best published methods. This paper extends the study of the continuous Berth Allocation Problem to the case of multiple quays, which is found in many container terminals around the world. Considering multiple quays adds a problem of assigning vessels to quays to the problem of determining berthing times and positions for each incoming vessel.This problem has not been considered in the literatur…
A New Technique of Invariant Statistical Embedding and Averaging in Terms of Pivots for Improvement of Statistical Decisions Under Parametric Uncerta…
2021
In this chapter, a new technique of invariant embedding of sample statistics in a decision criterion (performance index) and averaging this criterion via pivotal quantities (pivots) is proposed for intelligent constructing efficient (optimal, uniformly non-dominated, unbiased, improved) statistical decisions under parametric uncertainty. This technique represents a simple and computationally attractive statistical method based on the constructive use of the invariance principle in mathematical statistics. Unlike the Bayesian approach, the technique of invariant statistical embedding and averaging in terms of pivotal quantities (ISE&APQ) is independent of the choice of priors and represents …