211 research outputs found

    DCC: A Dependable Cache Coherence Multicore Architecture

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    Cache coherence lies at the core of functionally-correct operation of shared memory multicores. Traditional directory-based hardware coherence protocols scale to large core counts, but they incorporate complex logic and directories to track coherence states. Technology scaling has reached miniaturization levels where manufacturing imperfections, device unreliability and occurrence of hard errors pose a serious dependability challenge. Broken or degraded functionality of the coherence protocol can lead to a non-operational processor or user visible performance loss. In this paper, we propose a dependable cache coherence architecture (DCC) that combines the traditional directory protocol with a novel execution-migration-based architecture to ensure dependability that is transparent to the programmer. Our architecturally redundant execution migration architecture only permits one copy of data to be cached anywhere in the processor: when a thread accesses an address not locally cached on the core it is executing on, it migrates to the appropriate core and continues execution there. Both coherence mechanisms can co-exist in the DCC architecture and we present architectural extensions to seamlessly transition between the directory and execution migration protocols

    Sph modelling of long-term sway-sloshing motion in a rectangular tank

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    This work aims to model long-term simulations of sway-sloshing motion in a partially filled rectangular tank with different water depths and enforced motion frequencies. The lateral motion frequency of the tank is chosen so as to coincide with the lowest theoretical natural frequency for the corresponding beam of the tank and initial depth of water reserve. A truly meshless method, Smoothed Particle Hydrodynamics (SPH) is used to discretize and solve the governing equations. It is shown that numerical results of the proposed SPH scheme are in good agreement with experimental and numerical findings of the literature

    Olfactory Neuroblastomas: An Experience of 24 Years

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    Objective. The aim of this study was to evaluate clinicopathological findings and the efficacy of the treatment modalities used in patients with olfactory neuroblastomas. Study Design. Retrospective record review. Setting. Istanbul University, Cerrahpasa Medical Faculty, medical oncology outpatient clinic. Subjects and Methods. There were 3 stage A tumors, 5 stage B and 11 stage C according to the Kadish staging system. There were 5 grade I/II and 12 grade III/IV according to the Hyams' histopathologic system. Involvement to orbita was detected in eight patients at the time of diagnosis. Results. The median follow-up period was 23.7 months. The 5-year survival rate for the whole group was 26%. The stage A/B groups exhibited a better survival rate than the C group with 2-year survival rates being 25 versus 71% respectively (P = .008). The grade I/II groups exhibited a better survival rate than the grade III/IV groups with 2-year survival rates being 50 versus 16% respectively (P = .001). The group who had orbital involvement exhibited a poor survival rate than the group of patients who had no involvement of the orbital. Conclusion. In our study, tumor stage, histopathologic grading, involvement of the orbita, brain and bone marow metastases were the statistically significant prognostic factors

    Advanced Experiments on Gaussian Process-based Multi-fidelity Methods over Diverse Mathematical Characteristics

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    Advanced applications of multi-fidelity surrogate modelling techniques provide significant improvements in optimization and uncertainty quantification studies in many engineering fields. Multi-fidelity surrogate modelling can efficiently save the design process from the computational time burden caused by the need for numerous computationally expensive simulations. However, no consensus exists about which multi-fidelity surrogate modelling technique usually exhibits superiority over the other methods given for certain conditions. Therefore, the present paper focuses on assessing the performances of the Gaussian Process-based multi-fidelity methods across selected benchmark problems, especially chosen to capture diverse mathematical characteristics, by experimenting with their learning processes concerning different performance criteria. In this study, a comparison of Linear-Autoregressive Gaussian Process and NonlinearAutoregressive Gaussian Process methods is presented by using benchmark problems that mimic the behaviour of real engineering problems such as localized behaviours, multi-modality, noise, discontinuous response, and different discrepancy types. Our results indicate that the considered methodologies were able to capture the behaviour of the actual function sufficiently within the limited amount of budget for 1-D cases. As the problem dimension increases, the required number of training data increases exponentially to construct an acceptable surrogate model. Especially in higher dimensions, i.e. more than 5-D, local error metrics reveal that more training data is needed to attain an efficient surrogate for Gaussian Process based strategies

    Survival and Stage in Lung Cancer

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    Purpose: Lung cancer is the leading cause of cancer death worldwide. Although the 5-year survival rates of for non-small cell lung carcinoma (NSCLC) ranges from 20% to 70%. The present study investigates the rates of early recurrence in a total of 83 patients operated for NSCLC and presents the related findings in reference to the data available in the literature. Materials and Methods: Patients who underwent lung resection for malignancy between March 2019 and September 2021 were retrospectively examined. The patient data, including age, gender, presence of preoperative chemotherapy administration, opera-tions performed, operation dates, pathology results, postoperative staging, survival, and relapses, were documented. Results: A total of 83 patients who underwent lung resection for malignancy between March 2019 and September 2021 were examined. The patients had a median age of 62 years. Of the total number of patients four patients developed recurrence and 79 continued their follow-up without any recurrence. Of the patients who underwent lung resection, eight (9.6%) patients died within the first postoperative 2-year period. The mean survival period of these eight patients was 14.6 months (7–20 months). Conclusion: Although various parameters, such as age, gender, pathological type, and location of the tumor are examined and compared, according to the available data on the long-term survival of surgical patients, it is known that the only parameter that affects survival is the pathological stage of the patient

    The effects of metyrosine on ischemia-reperfusion-induced oxidative ovarian injury in rats: Biochemical and histopathological assessment

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    Abstract The aim of this study is to investigate the effect of metyrosine on ischemia-reperfusion (I/R) induced ovarian injury in rats in terms of biochemistry and histopathology. Rats were divided into: ovarian I/R (OIR), ovarian I/R+50 mg/kg metyrosine (OIRM) and sham (SG) operations. OIRM group received 50 mg/kg metyrosine one hour before the application of the anesthetic agent, OIR and SG group rats received equal amount of distilled water to be used as a solvent orally through cannula. Following the application of the anesthetic agent, ovaries of OIRM and OIR group rats were subjected to ischemia and reperfusion, each of which took two hours. This biochemical experiment findings revealed high levels of malondialdehyde (MDA) and cyclo-oxygenase-2 (COX-2) and low levels of total glutathione (tGSH), superoxide dismutase (SOD) and cyclo-oxygenase-1 (COX-1) in the ovarian tissue of OIR group, with significant histopathological injury. In metyrosine group, MDA and COX-2 levels were lower than the OIR group whereas tGSH, SOD and COX-1 levels were higher, with slighter histopathological injury. Our experimental findings indicate that metyrosine inhibits oxidative and pro-inflammatory damage associated with ovarian I/R in rats. These findings suggest that metyrosine could be useful in the treatment of ovarian injury associated with I/R
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