191 research outputs found

    BiDAl: Big Data Analyzer for Cluster Traces

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    Modern data centers that provide Internet-scale services are stadium-size structures housing tens of thousands of heterogeneous devices (server clusters, networking equipment, power and cooling infrastructures) that must operate continuously and reliably. As part of their operation, these devices produce large amounts of data in the form of event and error logs that are essential not only for identifying problems but also for improving data center efficiency and management. These activities employ data analytics and often exploit hidden statistical patterns and correlations among different factors present in the data. Uncovering these patterns and correlations is challenging due to the sheer volume of data to be analyzed. This paper presents BiDAl, a prototype “log-data analysis framework” that incorporates various Big Data technologies to simplify the analysis of data traces from large clusters. BiDAl is written in Java with a modular and extensible architecture so that different storage backends (currently, HDFS and SQLite are supported), as well as different analysis languages (current implementation supports SQL, R and Hadoop MapReduce) can be easily selected as appropriate. We present the design of BiDAl and describe our experience using it to analyze several public traces of Google data clusters for building a simulation model capable of reproducing observed behavior

    A comparative study of rehabilitation methods of patients with edentulous arches associated with insufficient bone volume

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    Ilarion Postolachi Department of Prosthodontics, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of MoldovaBackground: The rehabilitation of patients with insufficient bone support may be difficult because of multiple disturbances from stomatognathic system and the necessity to reestablish the lost bone volume. Material and methods: In this study were included 24 patients who were treated with conventional prosthesis (15 patients) and fixed implanting supported prosthesis (9 patients). Results: Implant-prosthetic rehabilitation with preliminary bone augmentation has esthetic, functional and biomechanical advantages over conventional prosthesis but it is more costly, traumatic and requires a long rehabilitation period with multiple surgical procedures. However, because of their disadvantages and hard conditions these prostheses are not always functional may not fully restore the lost functions of stomatognathic system. The necessity of additional surgical procedures, a higher cost and a longer rehabilitation time limit the applicability of this method. Conclusions: Implant supported prostheses provide a psychological comfort and prevent the progression of bone atrophy. Rehabilitation with conventional prostheses permits to restore the lost soft and hard tissue volume and patients’ integration into the society. Bone grafting allows restoring of lost soft and hard tissue volume which allows inserting of implants of standard size and manufacture of functional and aesthetical restorations. The questionnaire analysis has shown that patients that wore conventional prostheses for many years are usually unsatisfied by their performance and require implant prosthetic rehabilitation with fixed restorations. The last ones are well tolerated by patients and provide a psychological comfort that cannot be achieved with conventional prostheses

    In-stent restenosis in the drug eluting stent assayed by optical coherence tomography

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    Hospital of Holy Pope Giovanni XXIII, Bergamo, Italy, Department of Interventional Cardiology, Institute of Cardiology, Chisinau, the Republic of MoldovaBackground: In order to study the mechanisms and morphological aspects of the in-stent restenosis (ISR) have been evaluated restenosis lesions referred to drug eluting stent (DES) of the first generation using optical coherence tomography technique (OCT). Material and methods: The study underwent 39 patients with ISR induced recurrent angina or acute coronary syndrome including 66 stents from which were: 44 stents (28 patients) of the first generation of DES (19 – Cypher TM and 23 – Taxus®), and 22 stents (11 patients) of the second DES generation (9 Xience TM 2 Promus TM), 10 ZES (Resolute TM), and one stent Nobori TM. Has been made quantitative and morphological analysis of tissue pattern of ISR using the following OCT criteria: 1) morphologically homogenous neointima; 2)morphologically heterogeneous neointima; and 3) neoatherosclerosis. Results: It has been established that in the first generation of DES morphological homogenous pattern was present in both ISR developed after 1 year and later. However, the optical aspect with heterogeneous presentation had a prevalence decline in dynamics. The heterogeneous model had a higher prevalence in actual generation of DES in both incipient (< 1 year) and late presentation. Conclusions: The phenomenon of neoatherosclerosis has presented a significantly less frequency in the late restenosis of actual generation of DES. Our results suggest that restenosis phenomenon in actual generation of DES has a different morphological and evolution pattern in time in comparison with ISR of the first generation of DES

    Intracoronary optical coherence tomography

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    The cardiovascular departments of the hospital of Holy Pope Giovanni XXIII in Bergamo, Italy and of the Institute of Cardiology in Chisinau, the Republic of Moldova have a fruitful history of collaboration in the field of interventional cardiology and intracoronary imaging in particular. We have recently expanded our collaboration by adding the method of Optical Coherence Tomography (OCT) into the armamentarium of imaging in the catheterization laboratory. OCT is an innovative, real time, tomographic imaging modality able to visualize tissues at microstructure level. It delivers the rays of near-infrared light through the wall of the coronary artery using small diameter optical fibres. The light that illuminates the vessel is absorbed and backscattered or reflected by the structures of the tissues with different degrees of density, thus creating an image with an axial resolution of 10-20 µm. This technology allows acquiring high definition images of long segments of coronaries for a few seconds. For the time being, OCT is mainly used in the researches, providing insights into the pathophysiology of the atherosclerotic plaque and the vascular response to stenting. It also has a potential for clinical application, such as pre-interventional evaluation of coronary arteries, procedures guidance and follow-up assessment of vascular healing after the stent implantation. A joined database has been created by the two institutions in an effort to study in vivo the morphology of the coronary arteries in different pathologies. This review is focused on the potential fields of application of OCT in different clinical and scientific institutions

    Review of high-contrast imaging systems for current and future ground- and space-based telescopes I. Coronagraph design methods and optical performance metrics

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    The Optimal Optical Coronagraph (OOC) Workshop at the Lorentz Center in September 2017 in Leiden, the Netherlands gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate the emergence and sharing of new ideas. In this first installment of a series of three papers summarizing the outcomes of the OOC workshop, we present an overview of design methods and optical performance metrics developed for coronagraph instruments. The design and optimization of coronagraphs for future telescopes has progressed rapidly over the past several years in the context of space mission studies for Exo-C, WFIRST, HabEx, and LUVOIR as well as ground-based telescopes. Design tools have been developed at several institutions to optimize a variety of coronagraph mask types. We aim to give a broad overview of the approaches used, examples of their utility, and provide the optimization tools to the community. Though it is clear that the basic function of coronagraphs is to suppress starlight while maintaining light from off-axis sources, our community lacks a general set of standard performance metrics that apply to both detecting and characterizing exoplanets. The attendees of the OOC workshop agreed that it would benefit our community to clearly define quantities for comparing the performance of coronagraph designs and systems. Therefore, we also present a set of metrics that may be applied to theoretical designs, testbeds, and deployed instruments. We show how these quantities may be used to easily relate the basic properties of the optical instrument to the detection significance of the given point source in the presence of realistic noise.Comment: To appear in Proceedings of the SPIE, vol. 1069

    The original formula for predicting the survival of gastric cancer patients undergoing surgical treatment

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    The purpose of this work was to find ways to predict the survival of gastric cancer patients. The study included 221 patients who were radically operated in the abdominal department of the Odessa Regional Oncology Center from 2007 to 2013. The life expectancy of this group of patients was measured in months. From the factors given in the article, only the age of the patient, the presence and invasion in neighboring organs and the number of organs resected during the operation were those factors that had a significant impact on the prognosis. A formula was obtained for the formal evaluation of the duration of patients. The results are preliminary. Conclusions. As a result of the regression analysis, a polynomial (formula) was obtained, which can be used to predict the survival of patients who underwent surgery for gastric cancer. There is a need to create clearer gradations of survival dependencies of cancer patients from different clinical and morphological situations. A mathematical apparatus with many variables can be used to create similar models for the analysis of survival in other types of pathology

    Lymph node dissection impact on long-term survival rate of gastric cancer patients in Ukraine

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    Over a period of 2007-2011 188 stomach cancer (SC) patients have been included in the research in abdominal oncosurgical department of Odessa oncological center. Volume of lymph node dissections differed by quantity of lymph nodes to be removed. All patients were divided into three groups. Patients with D1 or D1+ lymph node dissections have been performed, totally 90 patients are included in group of historical control. In all cases so-called lymph node dissections for principal reasons have been executed. The multifactorial analysis of patients survival is implemented depending on a type of a lymph node dissections, a stage of the cancer, number of involved lymph nodes, involvement of the tumoral microcirculatory net (ly is carried out, v) signs of a perinevral invasion (Nev), availability of residual tumoral tissue (R), degree of a differentiation (G). Regardless of a disease stage, SC at 60 % of patients, represented with initially hematologicaly disseminated disease. 40 % of SC`s had no signs of intratumoral microcirculatory net involvement even in case of more than 15 regional lymph nodes are involved
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