98 research outputs found

    Reliability Analysis of Metro Door System Based on Fuzzy Multi-State Bayesian Network

    Get PDF
    Considering the shortcomings of the fault tree analysis (FTA) method in the reliability analysis of metro door systems, Bayesian network (BN) and fuzzy theory were introduced to establish the failure probability model of a metro door system. A fault tree of the metro door system was established based on the structure of the metro door, the operation data record and the practical experience of relevant engineers. The BN of the metro door system was constructed based on the fault tree. For the problem that the prior probabilities of root nodes with missing data were unavailable, fuzzy theory was introduced to convert the expert language values on these missing data nodes to corresponding prior probabilities, which were substituted into the BN along with the root nodes whose prior probabilities were obtained from the operation fault data to calculate the leaf node probability. Cause analysis of the metro door system was performed with bi-directional reasoning of BN, which provided a way to find the key factors that caused door faults and the metro door system fault probabilities

    Meta-analysis of the effect and clinical significance of Delphian lymph node metastasis in papillary thyroid cancer

    Get PDF
    ObjectiveTo investigate the effect and clinical significance of Delphian lymph nodes (DLN) on the factors influencing papillary thyroid cancer (PTC) to provide individualized guidance for the surgical treatment of thyroid cancer.MethodsRelevant studies from PubMed, Web of Science, the Cochrane Library, Embase, and China National Knowledge Infrastructure databases were searched until February 13, 2023. Stringent selection parameters were used to obtain included data and homogeneous articles. Analyses were performed using Revman 5.4 and SPSS software. A P-value of < 0.05 was considered statistically significant.ResultsFive studies were finally included in this study. The results revealed a higher risk of DLN metastasis (DLNM) in patients with tumor size >1cm, multifocality, and extrathyroidal extension (ETE) of the thyroid. The risk of central lymph node metastasis (CLNM) was 11.25 times higher in DLN-positive patients with PTC than in DLN-negative (OR = 11.25, 95% CI: 8.64–14.64, P < 0.05) patients. The risk of LLNM was 5.57 times higher in DLN-positive patients with PTC than in DLN-negative (OR = 5.57, 95% CI: 4.57–6.78, P < 0.001) patients. The risk of postoperative recurrence in DLN-positive patients with PTC was 3.49 times higher (OR = 3.49, 95% CI: 1.91–6.38, P < 0.001) than in DLN-negative patients with PTC.ConclusionPatients with tumor size >1 cm in diameter, multifocality, and ETE have an increased risk for DLN development. DLN-positive patients with central and lateral cervical lymph node metastasis and postoperative recurrence are at higher risk than DLN-negative patients

    Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial

    Get PDF
    Background: Previous cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes. Methods: We conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment. Results: Forty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference − 0.40 [95% CI − 0.71 to − 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference − 1.6% [95% CI − 4.3% to 1.2%]; P = 0.42) between groups. Conclusions: In this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness. Trial registration: ISRCTN, ISRCTN12233792. Registered November 20th, 2017

    Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial.

    Get PDF
    BackgroundPrevious cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes.MethodsWe conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment.ResultsForty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference - 0.40 [95% CI - 0.71 to - 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference - 1.6% [95% CI - 4.3% to 1.2%]; P = 0.42) between groups.ConclusionsIn this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness.Trial registrationISRCTN, ISRCTN12233792 . Registered November 20th, 2017

    Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial (vol 26, 46, 2022)

    Get PDF
    BackgroundPrevious cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes.MethodsWe conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment.ResultsForty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference - 0.40 [95% CI - 0.71 to - 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference - 1.6% [95% CI - 4.3% to 1.2%]; P = 0.42) between groups.ConclusionsIn this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness.Trial registrationISRCTN, ISRCTN12233792 . Registered November 20th, 2017

    Undersökning av optimala vÄgformsparametrar för jetting med Bayesiansk optimering

    No full text
    Jet printing is a method in surface mount technology (SMT) in which small volumes of solder paste or other electronic materials are applied to printed circuit boards (PCBs). The solder paste is shot onto the boards by a piston powered by a piezoelectric stack. The characteristics of jetted results can be controlled by a number of factors, one of which is the waveform of the piezo actuation voltage signal. While in theory any waveform is possible, in practice, the signal is defined by seven parameters for the specific technology studied here. The optimization problem of finding the optimal parameter combination cannot be solved by standard derivative based methods, as the objective is a black-box function which can only be sampled though noisy and time-consuming evaluations. The current method for optimizing the parameters is an expert guided grid search of the two most important parameters, while the remaining five are kept constant at default values. Bayesian optimization is a heuristic model based search method for efficient optimization of possibly noisy functions with unavailable derivatives. An implementation of the Bayesian optimization algorithm was adapted for the optimization of the waveform parameters, and used to optimize various combinations of the parameters. Results from different trials produced similar values for the two known parameters, with differences within the uncertainty caused by noise. For the remaining five parameters results were more ambiguous. However, a closer examination of the model hyperparameters showed that these five parameters had almost no impact on the objective function. Thus, the best found parameter values were affected more by random noise than the objective. It is concluded that Bayesian optimization might be a suitable and effective method for waveform parameter optimization, and some directions for further development are suggested based on the results of this project.Jet printing Àr en metod för att applicera lodpasta eller andra elektroniska material pÄ kretskort inom ytmontering inom elektronikproduktion. Lodpastan skjuts ut pÄ kretskorten med hjÀlp av en pistong som drivs av piezoelektrisk enhet. Kvaliteten pÄ det jettade resultatet kan pÄverkas av en mÀngd faktorer, till exempel vÄgformen av signalen som anvÀnds för att aktivera piezoenheten. I teorin Àr vilken vÄgform som helst möjlig, men i praktiken anvÀnds en vÄgform som definieras av sju parametrar. Att hitta optimala vÀrden pÄ dessa parametrar Àr ett optimeringsproblem som inte kan lösas med metoder baserade pÄ derivata, dÄ optimeringens mÄlfunktion Àr en s.k. svart lÄda (black-box function) som bara Àr tillgÀnglig via brusiga och tidskrÀvande evalueringar. Den nuvarande metoden för optimering av parametrarna Àr en modifierad gridsökning för de tvÄ viktigaste parametrarna dÀr de kvarvarande fem parametrarna Àr fixerade. Bayesiansk optimering Àr en heuristisk modell-baserad sökmetod för dataeffektiv optimering av brusiga funktioner för vilka derivator inte kan berÀknas. En implementation av Bayesiansk optimering anpassades för optimering av vÄgformsparametrar och anvÀndes för att optimera en mÀngd kombinationer av parametrarna. Alla resultaten gav liknande vÀrden för de tvÄ kÀnda parametrarna, med skillnader inom osÀkerheten frÄn mÀtbrus. Resultaten för de övriga fem parametrarna var motstridiga, men en nÀrmare granskning av hyperparametrar för modellen visade att detta berodde pÄ att de fem parametrarna bara har en minimal pÄverkan pÄ det jettade resultatet. DÀrför kan de motstridiga resultaten förklaras helt som skillnader pÄ grund av mÀtbrus. Baserat pÄ resultaten verkar Bayesiansk optimering vara en passande och effektiv metod för optimering av vÄgformsparametrar. Slutligen föreslÄs nÄgra möjligheter för vidare utveckling av metoden

    Undersökning av optimala vÄgformsparametrar för jetting med Bayesiansk optimering

    No full text
    Jet printing is a method in surface mount technology (SMT) in which small volumes of solder paste or other electronic materials are applied to printed circuit boards (PCBs). The solder paste is shot onto the boards by a piston powered by a piezoelectric stack. The characteristics of jetted results can be controlled by a number of factors, one of which is the waveform of the piezo actuation voltage signal. While in theory any waveform is possible, in practice, the signal is defined by seven parameters for the specific technology studied here. The optimization problem of finding the optimal parameter combination cannot be solved by standard derivative based methods, as the objective is a black-box function which can only be sampled though noisy and time-consuming evaluations. The current method for optimizing the parameters is an expert guided grid search of the two most important parameters, while the remaining five are kept constant at default values. Bayesian optimization is a heuristic model based search method for efficient optimization of possibly noisy functions with unavailable derivatives. An implementation of the Bayesian optimization algorithm was adapted for the optimization of the waveform parameters, and used to optimize various combinations of the parameters. Results from different trials produced similar values for the two known parameters, with differences within the uncertainty caused by noise. For the remaining five parameters results were more ambiguous. However, a closer examination of the model hyperparameters showed that these five parameters had almost no impact on the objective function. Thus, the best found parameter values were affected more by random noise than the objective. It is concluded that Bayesian optimization might be a suitable and effective method for waveform parameter optimization, and some directions for further development are suggested based on the results of this project.Jet printing Àr en metod för att applicera lodpasta eller andra elektroniska material pÄ kretskort inom ytmontering inom elektronikproduktion. Lodpastan skjuts ut pÄ kretskorten med hjÀlp av en pistong som drivs av piezoelektrisk enhet. Kvaliteten pÄ det jettade resultatet kan pÄverkas av en mÀngd faktorer, till exempel vÄgformen av signalen som anvÀnds för att aktivera piezoenheten. I teorin Àr vilken vÄgform som helst möjlig, men i praktiken anvÀnds en vÄgform som definieras av sju parametrar. Att hitta optimala vÀrden pÄ dessa parametrar Àr ett optimeringsproblem som inte kan lösas med metoder baserade pÄ derivata, dÄ optimeringens mÄlfunktion Àr en s.k. svart lÄda (black-box function) som bara Àr tillgÀnglig via brusiga och tidskrÀvande evalueringar. Den nuvarande metoden för optimering av parametrarna Àr en modifierad gridsökning för de tvÄ viktigaste parametrarna dÀr de kvarvarande fem parametrarna Àr fixerade. Bayesiansk optimering Àr en heuristisk modell-baserad sökmetod för dataeffektiv optimering av brusiga funktioner för vilka derivator inte kan berÀknas. En implementation av Bayesiansk optimering anpassades för optimering av vÄgformsparametrar och anvÀndes för att optimera en mÀngd kombinationer av parametrarna. Alla resultaten gav liknande vÀrden för de tvÄ kÀnda parametrarna, med skillnader inom osÀkerheten frÄn mÀtbrus. Resultaten för de övriga fem parametrarna var motstridiga, men en nÀrmare granskning av hyperparametrar för modellen visade att detta berodde pÄ att de fem parametrarna bara har en minimal pÄverkan pÄ det jettade resultatet. DÀrför kan de motstridiga resultaten förklaras helt som skillnader pÄ grund av mÀtbrus. Baserat pÄ resultaten verkar Bayesiansk optimering vara en passande och effektiv metod för optimering av vÄgformsparametrar. Slutligen föreslÄs nÄgra möjligheter för vidare utveckling av metoden
    • 

    corecore