1,104 research outputs found

    Multidimensional Binary Vector Assignment problem: standard, structural and above guarantee parameterizations

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    In this article we focus on the parameterized complexity of the Multidimensional Binary Vector Assignment problem (called \BVA). An input of this problem is defined by mm disjoint sets V1,V2,,VmV^1, V^2, \dots, V^m, each composed of nn binary vectors of size pp. An output is a set of nn disjoint mm-tuples of vectors, where each mm-tuple is obtained by picking one vector from each set ViV^i. To each mm-tuple we associate a pp dimensional vector by applying the bit-wise AND operation on the mm vectors of the tuple. The objective is to minimize the total number of zeros in these nn vectors. mBVA can be seen as a variant of multidimensional matching where hyperedges are implicitly locally encoded via labels attached to vertices, but was originally introduced in the context of integrated circuit manufacturing. We provide for this problem FPT algorithms and negative results (ETHETH-based results, WW[2]-hardness and a kernel lower bound) according to several parameters: the standard parameter kk i.e. the total number of zeros), as well as two parameters above some guaranteed values.Comment: 16 pages, 6 figure

    Approximate logic synthesis: a survey

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    Approximate computing is an emerging paradigm that, by relaxing the requirement for full accuracy, offers benefits in terms of design area and power consumption. This paradigm is particularly attractive in applications where the underlying computation has inherent resilience to small errors. Such applications are abundant in many domains, including machine learning, computer vision, and signal processing. In circuit design, a major challenge is the capability to synthesize the approximate circuits automatically without manually relying on the expertise of designers. In this work, we review methods devised to synthesize approximate circuits, given their exact functionality and an approximability threshold. We summarize strategies for evaluating the error that circuit simplification can induce on the output, which guides synthesis techniques in choosing the circuit transformations that lead to the largest benefit for a given amount of induced error. We then review circuit simplification methods that operate at the gate or Boolean level, including those that leverage classical Boolean synthesis techniques to realize the approximations. We also summarize strategies that take high-level descriptions, such as C or behavioral Verilog, and synthesize approximate circuits from these descriptions

    A radiation free alternative to CBCT volumetric rendering for soft tissue evaluation

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    Objective: The aim of the present study is to evaluate whether a “radiation free” method using 3D facial scan can replace Cone Beam Computed Tomography (CBCT) volumetric rendering of soft tissue of the patient to assess maxillofacial surgery outcomes and compare the reference points and angular measurements of patient facial soft tissue. Material and Methods: Facial soft tissue scan of the patient’s face, before and after orthognathic surgery and a CBCT of the skull for volumetric rendering of soft tissues were carried out. The 3D acquisitions were processed using Planmeca ProMax 3D ProFace® software (Planmeca USA, Inc.; Roselle, Illinois, USA). The participant were positioned in a natural position during the skull scannering. Three sagittal angular measurements were performed (Tr-NA, Tr-N-Pg, Ss-N-Pg) and two verticals (Go-N-Me, Tr-Or-Pg) on facial soft tissue scan and on the patient’s 3D soft tissue CBCT volumetric rendering. Results: A certain correspondence has been demonstrated between the measurements obtained on the Proface and those on the CBCT. Conclusion: A radiation free method was to be considered an important diagnostic tool that works in conditions of not subjecting the patient to harmful ionizing radiation and it was therefore particularly suitable for growing subjects. The soft tissue analysis based on the realistic facial scan has shown sufficient reliability and reproducibility even if further studies are needed to confirm the research result

    Laser microgrooved vs. machined healing abutment disconnection/reconnection: a comparative clinical, radiographical and biochemical study with split-mouth design

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    Background: Repeated removal and replacement of healing abutments result in frequent injuries to the soft tissues.Purpose: The purpose of this study was to evaluate the effect of disconnection/reconnection of laser microgrooved vs. machined healing and prosthetic abutments on clinical periodontal parameters, marginal bone levels, and proinflammatory cytokine levels around dental implants.Material and methods: Twenty-four patients each received 2 implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one healing and prosthetic abutments with a laser microgrooved surface (LMS group) and one healing and prosthetic abutments with machined surface (MS group) were used. Four months following implant placement (T0), the healing abutments were disconnnected and reconnected three times to carry out the impression procedures and metal framework try-in. Four weeks later (T1), definitive prosthetic abutments were installated with screw-retained crowns. Modified plaque index (mPI), modified gingival index (mGI) bleeding on probing (BOP), and probing depth (PD) were recorded at T0 and T1. At the same time points, samples for immunological analyses were taken from the sulcus around each implant. Peri-implant crevicular fluid (PICF) samples were analyzed for interleukin-1beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-alpha levels using the ELISA kit.Results: At T0 and T1, mPI and mGI showed no statistical difference between the two groups, while higher PD and BoP values were noted for the MS group (P < 0.05). The mean PICF volume and mean concentrations of IL-1 beta, IL-6, and (TNF)-alpha in the LMS group were statistically less than those in the MS group (P < 0.05). In addition, comparison of IL-6 and IL-1 beta mean concentrations at T0 and T1 in the MS group showed a statistically significant increase (p < 0.05) over time, which was not noted for the LMS.Conclusion: Disconnection/reconnection of healing and prosthetic abutments with a laser-microgrooved surface resulted in less inflammatory molecular response compared with conventional machined ones

    A comprehensive in vitro comparison of mechanical properties of two rotary endodontic instruments

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    Aim: The aim of the present study was to compare two different nickel–titanium (NiTi) rotary files, F-One Blue and F2 Protaper Gold (PTG), evaluating their properties such as cyclic fatigue resistance, torsional resistance, and bending properties. Materials and methods: Sixty F-One Blue (25.06) and 60 PTGF2 have been randomly divided into 3 groups of 20 instruments each. Each group was tested in a different way, in order to analyze three different properties: cyclic fatigue resistance, torsional resistance, and flexibility. Cyclic fatigue resistance was evaluated by inserting the instruments for 16 mm in a stainless-steel artificial canal with a 90° angle and 5 mm of curvature with recommended speed and torque. Time to fracture was recorded using a chronometer (1/100 seconds). The number of cycles to fracture (NCF) was then calculated. Fragments were collected, and their lengths were measured. Torsional resistance was evaluated on the apical 3 mm of each of the files to calculate torque to fracture (TtF) using an endodontic motor (KaVo, Biberach, Germany), which automatically recorded the torque values every 1/10 s. All instruments were rotated at the same speed (300 rpm) and torque value (5.5 Ncm). Flexibility was evaluated using a calibrated load cell supported by a computer program. All the collected data were statistically analyzed (t-test) with a significance level set at 5%. Results: A significant difference in terms of cyclic fatigue resistance, torsional resistance, and flexibility between F-One Blue and F2 PTG was found (p < 0.05). The mean value of NCF was 604.16 (SD ± 23.32) for F-One Blue and 300.5 (SD 19.92) for F2 PTG. The mean value of TtF was 1.41 Ncm (SD ± 0.01) and 1.39 Ncm (SD ± 0.01) for F2 PTG. The mean value of bending test was 29 gcm (SD ± 1.15) for F-One Blue and 50 gcm (SD ± 2.30) for F2 PTG. Conclusion: F-One Blue better resists to flexural and torsional stresses and seemed to be more flexible. Since F-One Blue mechanical tested performances were better than the F2 PTG ones, these instruments should be considered a very promising instrument. Clinical significance: As evidenced by the results of this study, F-One Blue should be considered a very promising instrument that could improve endodontic clinical practice

    COVID-19 Detection on Chest x-ray Images by Combining Histogram-oriented Gradient and Convolutional Neural Network Features

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    The COVID-19 coronavirus epidemic has spread rapidly worldwide after a person became infected with a severe health problem. The World Health Organization has declared the coronavirus a global threat (WHO). Early detection of COVID 19, particularly in cases with no apparent symptoms, may reduce the patients mortality rate. COVID 19 detection using machine learning techniques will aid healthcare systems around the world in recovering patients more rapidly. This disease is diagnosed using x-ray images of the chest; therefore, this study proposed a machine vision method for detecting COVID-19 in x-ray images of the chest. The histogram-oriented gradient (HOG) and convolutional neural network (CNN) features extracted from x-ray images were fused and classified using support vector machine (SVM) and softmax. The proposed feature fusion technique (99.36 percent) outperformed individual feature extraction methods such as HOG (87.34 percent) and CNN (93.64 percent)

    Novel patient-centered approach to facilitate same-day discharge in patients undergoing elective percutaneous coronary intervention

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    Background Same‐day discharge ( SDD ) after elective percutaneous coronary intervention is safe, less costly, and preferred by patients, but it is usually performed in low‐risk patients, if at all. To increase the appropriate use of SDD in more complex patients, we implemented a “patient‐centered” protocol based on risk of complications at Barnes‐Jewish Hospital. Methods and Results Our objectives were as follows: (1) to evaluate time trends in SDD ; (2) to compare (a) mortality, bleeding, and acute kidney injury, (b) patient satisfaction, and (c) hospital costs by SDD versus no SDD ( NSDD ); and (3) to compare SDD eligibility by our patient‐centered approach versus Society for Cardiovascular Angiography and Interventions guidelines. Our patient‐centered approach was based on prospectively identifying personalized bleeding, mortality, and acute kidney injury risks, with a personalized safe contrast limit and mitigating those risks. We analyzed Barnes‐Jewish Hospital's National Cardiovascular Data Registry Cath PCI Registry data from July 1, 2009 to September 30, 2015 (N=1752). SDD increased rapidly from 0% to 77% ( P &lt;0.001), independent of radial access. Although SDD patients were comparable to NSDD patients, SDD was not associated with adverse outcomes (0% mortality, 0% bleeds, and 0.4% acute kidney injury). Patient satisfaction was high with SDD . Propensity score–adjusted costs were 7331 lower/ SDD patient ( P <0.001), saving an estimated 1.8 million annually. Only 16 patients (6.95%) met the eligibility for SDD by Society for Cardiovascular Angiography and Interventions guidelines, implying our patient‐centered approach markedly increased SDD eligibility. Conclusions With a patient‐centered approach, SDD rapidly increased and was safe in 75% of patients undergoing elective percutaneous coronary intervention, despite patient complexity. Patient satisfaction was high, and hospital costs were lower. Patient‐centered decision making to facilitate SDD is an important opportunity to improve the value of percutaneous coronary intervention. </jats:sec

    The effect of caffeine ingestion in prevention of post-operative ileus after caesarean section: a randomized controlled trial

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    Background: Caesarian section (CS) has become more prevalent than the vaginal delivery in Egypt. Many complications could occur after an abdominal surgery. One of the commonest but yet serious complications is the postoperative ileus that can possibly be prevented by caffeine ingestion. The aim of the study is to assess the value of caffeine ingestion in promoting intestinal motility and prevention of postoperative ileus after CS.Methods: This is a randomized controlled trial that was conducted on 560 cases who were recruited from emergency unit and inpatient wards in Ain Shams University maternity hospital. The patients were divided into two groups where the intervention group received caffeinated coffee while the other group received decaffeinated coffee.Results: There was statistically significant difference between the two groups regarding the bowel function after CS (p <0.05). The intervention group had improved intestinal functions after the CS. Patients from the intervention group had audible intestinal sound sooner than the control group. In addition, they passed flatus and were able to tolerate food in less time.Conclusions: Consuming caffeinated coffee after CS contributes significantly to faster restoration of intestinal function. Coffee is a popular drink and can be used to decrease the incidence of postoperative ileus-related complications
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