Optimal sliding friction coefficient for isolated bridges in different soil conditions

The work evaluates the optimal properties of friction pendulum system (FPS) bearings for the seismic protection of bridge piers under earthquake excitations having different frequency characteristics representative of different soil conditions in order to reduce the seismic vulne-rability of infrastructures. A two-degree-of-freedom model is adopted to describe, respective-ly, the response of the infinitely rigid deck isolated by the FPS devices and the elastic behavior of the pier. By means of a non-dimensional formulation of the motion equations, a wide parametric analysis for several structural parameters is carried out. Seismic excitations, modelled as time-modulated filtered Gaussian white noise random processes having different intensities and frequency contents, are considered. Specifically, the filter parameters, which control the frequency contents, are properly calibrated to reproduce stiff, medium and soft soil conditions, respectively. Finally, the optimum values of the sliding friction coefficient able to minimize the pier displacements with respect to the ground are derived as a function of the structural properties, of the seismic input intensity and of the soil condition

Learning-based scheduling of flexible manufacturing systems using ensemble methods

Dispatching rules are commonly applied to schedule jobs in Flexible Manufacturing Systems (FMSs). However, the suitability of these rules relies heavily on the state of the system; hence, there is no single rule that always outperforms the others. In this scenario, machine learning techniques, such as support vector machines (SVMs), inductive learning-based decision trees (DTs), backpropagation neural networks (BPNs), and case based-reasoning (CBR), offer a powerful approach for dynamic scheduling, as they help managers identify the most appropriate rule in each moment. Nonetheless, different machine learning algorithms may provide different recommendations. In this research, we take the analysis one step further by employing ensemble methods, which are designed to select the most reliable recommendations over time. Specifically, we compare the behaviour of the bagging, boosting, and stacking methods. Building on the aforementioned machine learning algorithms, our results reveal that ensemble methods enhance the dynamic performance of the FMS. Through a simulation study, we show that this new approach results in an improvement of key performance metrics (namely, mean tardiness and mean flow time) over existing dispatching rules and the individual use of each machine learning algorithm

Applying machine learning to the dynamic selection of replenishment policies in fast-changing supply chain environments

Firms currently operate in highly competitive scenarios, where the environmental conditions evolve over time. Many factors intervene simultaneously and their hard-to-interpret interactions throughout the supply chain greatly complicate decision-making. The complexity clearly manifests itself in the field of inventory management, in which determining the optimal replenishment rule often becomes an intractable problem. This paper applies machine learning to help managers understand these complex scenarios and better manage the inventory flow. Building on a dynamic framework, we employ an inductive learning algorithm for setting the most appropriate replenishment policy over time by reacting to the environmental changes. This approach proves to be effective in a three-echelon supply chain where the scenario is defined by seven variables (cost structure, demand variability, three lead times, and two partners’ inventory policy). Considering four alternatives, the algorithm determines the best replenishment rule around 88% of the time. This leads to a noticeable reduction of operating costs against static alternatives. Interestingly, we observe that the nodes are much more sensitive to inventory decisions in the lower echelons than in the upper echelons of the supply chain

Ozone therapy in extractive surgery on patients treated with bisphosphonates

It is certain that oral extractive surgery is a remarkable trigger to avascular osteonecrosis of the jaw in patients treated with pyrophosphate analogous. This acquisition limits the use of endo-oral surgery in those patients, even when they have already developed the lesions. In this study, we present the results obtained in a group of 15 patients deriving from a 33-patient cluster with osteonecrosis of the jaw in treatment at our department with a new protocol based on ozone therapy. The object of this article is to demonstrate how dental extraction becomes possible in a patient with avascular bisphosphonate-related jaw osteonecrosis or in those who simply received pyrophosphate analogous when proper treatment with ozone therapy has been done

Surgical management of the acromegalic face: Could the aesthetic improvement of the face influence the patient's QoL? Combined surgical approach

Acromegaly is a chronic and progressive disease related to a disorder of growth hormone production. It may present with a variety of clinical signs and a dento-facial deformity and this results in a loss of self-esteem and a reduction of Quality of Life. Presentation of case: A 38-years–old male patient, affected by acromegaly with class III malocclusion, noticeable nose deformity and macroglossia was treated. Bi-maxillary orthognathic surgery and partial glossectomy have been performed in one-step surgey. Open rhinoplasty was done in a second step. Both dento-skeletal class III and restoration of the facial appearance have been solved. Dento-skeletal class III was completly solved together with the restoration of the facial appearance and the patient satisfaction has been achieved. Conclusions: This case report describes the successful and stable treatment of an adult patient affected by acromegaly

RFID in library management and maintenance

Radio frequency identification (RFID) is an emergent technology that is currently growing in importance. Companies can improve inventory control and track their products by gathering data from RFID labels on the products. Most of the applications for libraries use RFID of 13.56MHz or less, following ISO standards 15693 and 18000-3. The components and operation of an RFID system are described and applications in diverse sectors are noted, particularly with respect to libraries. A general RFID implementation model for a library is presented and practical applications currently in use are described, along with the benefits that result

Three-dimensional comparison of the maxillary surfaces through ICP-Type algorithm: accuracy evaluation of CAD/CAM technologies in orthognathic surgery

Purpose: This retrospective study aims to compare the accuracy of two different CAD/CAM systems in orthognathic surgery. The novelty of this work lies in the method of evaluating the accuracy, i.e., using an Iterative Closest Point (ICP) algorithm, which matches a pair of 2D or 3D point clouds with unknown dependencies of the transition from scan s(k) to scan s(k+1). Methods: The study population was composed of ten patients who presented to the Maxillofacial Surgery Department of the University “Sapienza” of Rome for the evaluation and management of skeletal malocclusions. The patients were divided into two groups, depending on the technique used: group 1: splintless group (custom-made cutting guide and plates); group 2: splint group (using a 3D-printed splint). STL files were imported into Geomagic® Control X™ software, which allows for comparison and analysis using an ICP algorithm. The RMSE parameter (3D error) was used to calculate the accuracy. In addition, data were compared in two different patient subgroups. The first subgroup only underwent a monobloc Le Fort I osteotomy (p-value = 0.02), and the second subgroup underwent a Le Fort I osteotomy associated with a segmental osteotomy of the maxilla (p-value = 0.23). Results: Group 1 showed a 3D error of 1.22 mm ± SD 0.456, while group 2 showed a 3D error of 1.63 mm ± SD 0.303. These results have allowed us to compare the accuracy of the two CAD/CAM systems (p-value = 0.09). Conclusions: The ICP algorithm provided a reproducible method of comparison. The splintless method would seem more accurate (p-value = 0.02) in transferring the surgical programming into the operating room when only a Le Fort I osteotomy is to be performed

Definición de un modelo de desarrollo y gestión de un parque empresarial de logística inversa en españa

El presente trabajo tiene por objeto realizar un análisis sobre las oportunidades de negocio que comienzan a surgir alrededor de la Logística Inversa, de tal forma que no sólo se contribuya a mejorar la eficiencia de las empresas industriales, sino que pueda llegar a constituir una opción estratégica en sí misma para la generación de valor. Se propone aquí la creación de un parque empresarial de Logística Inversa, que aglutine actividades diversas relacionadas con la valorización de residuos industriales y que se beneficie de las economías de escala, las sinergias generadas entre las empresas en él instaladas, la colaboración de los poderes públicos y el mejor acceso a la información. Los resultados empíricos obtenidos demuestran que el desarrollo de un parque de estas características también representa una oportunidad de negocio interesante para las empresas promotoras, en un momento de grave crisis del sector, especialmente en el caso de España

???Pull-through??? Resection for Total and Subtotal Glossectomy Involving the Posterior Third of Tongue

The lower lip-splitting incision associated with different types of mandibulotomy, in order to obtain wide access to total or subtotal glossectomy, is described. In those cases, high rates of functional and aesthetic deficit and postoperative morbidity (more in cases of patients in which adjuvant radiotherapy has been performed) are described. We present our experience in the treatment of patients undergoing total or subtotal glossectomy and contemporary reconstruction with flaps, and without lip-splitting incision and mandibulotomy. Materials and Methods: Data about patients affected by malignant tumors requiring total or subtotal (posterior third of the tongue) resection that were treated at our department from January 2004 to December 2014 were retrospectively reviewed. Data evaluated included: T and N stage, resection margins, operation time, and post-operative complications, such as fistula and flap necrosis. Results: 41 patients were identified. In two cases microscopic infiltration of one margin was found (R1); in one case a close margin was identified. In 26 cases reconstruction was performed using free flaps, and in the remaining cases a pectoralis major flap was used. In three cases postoperative complications were observed. Discussion and conclusions: In theory, lip-splitting and mandible discontinuity could allow for increased access and tumor visualization, and could facilitate flap positioning. Nevertheless, in our experience, it is not necessary in the case of total or subtotal glossectomy