Long-release-interval-first real-time scheduling algorithm and its schedulability test

To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first （LRIF） real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic priority to assign priorities for tasks. By assigning higher priorities to the aperiodic soft real-time jobs with longer release intervals, it guarantees the executions for periodic hard real-time tasks and further probabilistically guarantees the executions for aperiodic soft real-time tasks. The schedulability test approach for the LRIF algorithm is presented. The implementation issues of the LRIF algorithm are also discussed. Simulation result shows that LRIF obtains better schedulable performance than the maximum urgency first （MUF） algorithm, the earliest deadline first （EDF） algorithm and EDF for hybrid tasks. LRIF has great capability to schedule both periodic hard real-time and aperiodic soft real-time tasks.

Statistical Analysis for Constant-stress Partially Accelerated Life Test with Interval Censored Data

In this paper, a statistical analysis method is proposed to research life characteristics of products based on the partially accelerated life test. We discuss the statistical analysis for constant-stress partially accelerated life tests with Lomax distribution based on interval censored samples. The EM algorithm is used to obtain the maximum likelihood estimations(MLEs) and interval estimations for the shape parameter and acceleration factor.The average relative errors(AREs), mean square errors(MSEs), the confidence intervals for the parameters, and the influence of the sample size are discussed. The results show that the AREs and MSEs of the MLEs decrease with the increase of sample size. Finally, a simulation sample is used to estimate the reliability under different stress levels.

On the Power Performance of Test Statistics for the Generalized Rayleigh Interval Grouped Data

In this paper, the weighted Kolmogrov-Smirnov, Cramer von-Miss and the Anderson Darling test statistics are considered as goodness of fit tests for the generalized Rayleigh interval grouped data. An extensive simulation process is conducted to evaluate their controlling of type 1 error and their power functions. Generally, the weighted Kolmogrov-Smirnov test statistics show a relatively better performance than both, the Cramer von-Miss and the Anderson Darling test statistics. For large sample values, the Anderson Darling test statistics cannot control type 1 error but for relatively small sample values it indicates a better performance than the Cramer von-Miss test statistics. Best selection of the test statistics and highlights for future studies are also explored.

Colorectal and interval cancers of the Colorectal Cancer Screening Program in the Basque Country (Spain)

AIM To assess proportions, related conditions and survival of interval cancer(IC).METHODS The programme has a linkage with different clinical databases and cancer registers to allow suitable evaluation. This evaluation involves the detection of ICs after a negative faecal inmunochemical test(FIT), interval cancer FIT(IC-FIT) prior to a subsequent invitation, and the detection of ICs after a positive FIT and confirmatory diagnosis without colorectal cancer(CRC) detected and before the following recommended c o l o n o s c o p y, I C-c o l o n o s c o p y. W e c o n d u c t e d a retrospective observational study analyzing from January 2009 to December 2015 1193602 invited people onto the Programme(participation rate of 68.6%).RESULTS Two thousand five hundred and eighteen cancers were diagnosed through the programme, 18 cases of IC-colonoscopy were found before the recommended follow-up(43542 colonoscopies performed) and 186 IC-FIT were identified before the following invitation of the 769200 negative FITs. There was no statistically significant relation between the predictor variables of ICs with sex, age and deprivation index, but there was relation between location and stage. Additionally, it was observed that there was less risk when the location was distal rather than proximal(OR = 0.28, 95%CI: 0.20-0.40, P < 0.0001), with no statistical significance when the location was in the rectum as opposed to proximal. When comparing the screen-detected cancers(SCs) with ICs, significant differences in survival were found(P < 0.001); being the 5-years survival for SCs 91.6% and IC-FIT 77.8%.CONCLUSION These findings in a Population Based CRC Screening Programme indicate the need of population-based studies that continue analyzing related factors to improve their detection and reducing harm.

Bootstrap Confidence Intervals for Proportions of Unequal Sized Groups Adjusted for Overdispersion

Group testing is a method of pooling a number of units together and performing a single test on the resulting group. It is an appealing option when few individual units are thought to be infected leading to reduced costs of testing as compared to individually testing the units. Group testing aims to identify the positive groups in all the groups tested or to estimate the proportion of positives (p) in a population. Interval estimation methods of the proportions in group testing for unequal group sizes adjusted for overdispersion have been examined. Lately improvement in statistical methods allows the construction of highly accurate confidence intervals (CIs). The aim here is to apply group testing for estimation and generate highly accurate Bootstrap confidence intervals (CIs) for the proportion of defective or positive units in particular. This study provided a comparison of several proven methods of constructing CIs for a binomial proportion after adjusting for overdispersion in group testing with groups of unequal sizes. Bootstrap resampling was applied on data simulated from binomial distribution, and confidence intervals with high coverage probabilities were produced. This data was assumed to be overdispersed and independent between groups but correlated within these groups. Interval estimation methods based on the Wald, the Logit and Complementary log-log (CLL) functions were considered. The criterion used in the comparisons is mainly the coverage probabilities attained by nominal 95% CIs, though interval width is also regarded. Bootstrapping produced CIs with high coverage probabilities for each of the three interval methods.

Variation regularity of metal magnetic memory signals with inspecting time-interval and location

Influences of inspecting time-interval and location on varying behavior of metal magnetic memory (MMM) signals of defects were studied. Different areas in two precracked weldments were inspected at different time-intervals by type TSC-1M-4 stress-concentration magnetic inspector to obtain MMM signals. Mechanisms of MMM signals varying behavior with inspecting time and space were analyzed and discussed respectively. It is found that MMM signals don't change with inspecting time-interval, since stress field and magnetic leakage field maintain unchanged at any time after welding. On the other hand, MMM signals differ greatly for different inspecting locations, because stress field and magnetic leakage field are unevenly distributed in defective ferromagnetic materials.

Honesty, power and bootstrapping in composite interval quantitative trait locus mapping

In a typical composite interval mapping experiment, the probability of obtaining false QTL is likely to be at least an order of magnitude greater than the nominal experiment-wise Type I error rate, as set by permutation test. F2 mapping crosses were simulated with three different genetic maps. Each map contained ten QTL on either three, six or twelve linkage groups. QTL effects were additive only, and heritability was 50%. Each linkage group had 11 evenly-spaced (10 cM) markers. Selective genotyping was used. Simulated data were analyzed by composite interval mapping with the Zmapqtl program of QTL Cartographer. False positives were minimized by using the largest feasible number of markers to control genetic background effects. Bootstrapping was then used to recover mapping power lost to the large number of conditioning markers. Bootstrapping is shown to be a useful tool for QTL discovery, although it can also produce false positives. Quantitative bootstrap support—the proportion of bootstrap replicates in which a significant likelihood maximum occurred in a given marker interval—was positively correlated with the probability that the likelihood maxima revealed a true QTL. X-linked QTL were detected with much lower power than autosomal QTL. It is suggested that QTL mapping experiments should be supported by accompanying simulations that replicate the marker map, crossing design, sample size, and method of analysis used for the actual experiment.

A Tight Prediction Interval for False Discovery Proportion under Dependence

The false discovery proportion (FDP) is a useful measure of abundance of false positives when a large number of hypotheses are being tested simultaneously. Methods for controlling the expected value of the FDP, namely the false discovery rate (FDR), have become widely used. It is highly desired to have an accurate prediction interval for the FDP in such applications. Some degree of dependence among test statistics exists in almost all applications involving multiple testing. Methods for constructing tight prediction intervals for the FDP that take account of dependence among test statistics are of great practical importance. This paper derives a formula for the variance of the FDP and uses it to obtain an upper prediction interval for the FDP, under some semi-parametric assumptions on dependence among test statistics. Simulation studies indicate that the proposed formula-based prediction interval has good coverage probability under commonly assumed weak dependence. The prediction interval is generally more accurate than those obtained from existing methods. In addition, a permutation-based upper prediction interval for the FDP is provided, which can be useful when dependence is strong and the number of tests is not too large. The proposed prediction intervals are illustrated using a prostate cancer dataset.

Risk assessment of self-sampling HPV tests based on PCR, signal amplification to guide the appropriate screening intervals: A prospective study in China

Objective:We assessed the longitudinal risk of developing cervical intraepithelial neoplasia(CINs)with self-sampling human papillomavirus(HPV)tests,based on polymerase chain reaction(PCR)and signal amplification(care HPV),to explore the appropriate intervals for cervical cancer screening.Methods:A prospective study was conducted in China during 2017-2020.Participants were invited for PCR and care HPV tests with self-samples at baseline.Women positive in either HPV test underwent colposcopy and biopsy if necessary.Women with baseline CIN grade one(CIN1)or less were followed up over 3 years.The absolute risk was assessed by the immediate risk(IR)and cumulative risk(CR),and the relative risk was assessed by the hazard ratio(HR)with a 95%confidence interval(CI).Results:A total of 8,126 women were included in the final analysis.Women positive for the PCR HPV test had comparable IRs of CIN2+and CIN3+to those positive on the care HPV test.With triage by HPV genotyping,women with HPV 16/18 infection had the highest IRs of CIN2+(21.15%)and CIN3+(9.67%).For CR,women negative for PCR HPV test had a lower risk of CIN2+than that reported in women negative on care HPV test(0.57%versus 0.98%,HR=0.58,95%CI:0.38,0.87),but no significant difference was found in the CRs of CIN3+between them(0.25%versus 0.39%,HR=0.64,95%CI:0.34,1.20).Among women with CIN1 or less at baseline,women who were persistent or recurrent positive on care HPV or PCR HPV test had a higher risk of developing CIN3+(11.36%-14.59%),compared with women remained HPV negative from baseline throughout follow-up(≤0.28%).Conclusions:Routine screening with 3-year intervals is acceptable for self-sampling HPV tests based on PCR or care HPV test.Women positive on HPV16/18 triaging at baseline or with CIN1 or less at baseline while being per-sistent or recurrent positive on care HPV or PCR HPV test during 3-year follow-up require immediate colposcopy or treatment.

动态力学模拟试验信号产生系统结构设计

为解决现存高速碰撞动态力学模拟冲击试验存在的试验成本高、试验周期长,且无法实现连续多次高幅值冲击等问题,对高速连续冲击动态力学模拟试验信号产生系统结构进行了设计。通过对高速连续多次冲击信号进行靶场实测、仿真分析,揭示冲击信号特征,提出技术要求;根据信号特征,确定设计方案,利用“旋转式转盘+退让式冲击头”装置,产生连续多次高幅值、短间隔的冲击过载信号;通过模态分析及数值模拟,验证方案设计的可行性,并进行样机测试。结果表明:设计可实现模拟连续冲击大于10次,冲击幅值高于5000g,冲击时间间隔小于3 ms,且冲击时间间隔可调。设计可满足在实验室中对高速碰撞动力学信号的模拟检测,为实验室模拟高速连续冲击过程并进行冲击信号动态性能研究提供参考。

区间划分改进相似性的发动机剩余寿命预测

针对传统相似性匹配方法易引入伪相似发动机导致预测精度不高的问题,提出一种结合发动机性能退化特点与相似性匹配特点的区间划分改进相似性剩余寿命(RUL)预测方法。利用堆栈自编码器基于选择的参数构建健康指数;根据测试发动机的已知运行循环进行区间划分,利用传统相似性匹配方法进行初步筛选;对于不同区间下的测试发动机,分别使用不确定性修正和退化一致性检验去除初选参考发动机中的异常发动机,得到最终的剩余寿命预测结果。利用NASA的C-MAPSS数据集进行验证,结果表明:所提方法的预测精度比当前相似性匹配方法提升了34%,证明了方法的有效性。

拉萨地区儿童临床常用生化检验项目参考区间验证

目的验证卫生行业标准WS/T780-2021《儿童临床常用生化检验项目参考区间》,判断其是否适用于我实验室所服务的拉萨地区儿童。方法在拉萨市人民医院体检人群中筛选健康体检儿童,按照参考区间建立时的性别、年龄亚组划分标准,每亚组筛选合格参考个体不少于20名,按WS/T661《静脉血液标本采集指南》采集样本,在迈瑞BS2000全自动生化分析仪上进行生化项目检测,将检测结果与行标参考区间进行比较,并对各检测参数进行年龄性别间差异比较。结果17~18岁女孩碱性磷酸酶(ALP)符合率为73.6%,未通过验证;其余的各亚组符合率均>90%,通过验证。对各项目年龄组间差异分析,除血清氯(Cl)在年龄组间差异无统计学意义,其余各项目在年龄组间差异均有统计学意义(P<0.05)。对相同年龄段性别间差异分析,天门冬氨酸氨基转移酶(AST)13~18岁男女组间差异无统计学意义,无机磷(IP)15~18岁男女组间差异无统计学意义,其余各项目在相同年龄段性别间差异均有统计学意义(P<0.05)。结论《儿童临床常用生化检验项目参考区间》基本适用于拉萨地区儿童,17~18岁女孩碱性磷酸酶参考区间应单独制定;儿童生化检验项目在不同年龄及性别间有较大差异,实验室在引用或建立儿童生化项目参考区间时应重视年龄及性别划分。

基于静压恢复规律的间抽制度研究

在油田生产过程中,间抽是解决低产低效、举升单耗高等问题的有效手段,不仅可以提高泵的充满程度,还可以提高系统效率,亟需制定合理的间抽制度。以油井的静压测试曲线为基础,通过研究IPR曲线类型、液面变化规律、沉没度与泵效的关系,IPR曲线存在有拐点和无拐点2种类型,液面变化先快后慢,恢复至原液面抽汲时间远长于停机时间,泵效在一定沉没度范围内基本不变,为提高间抽效率,采取调大参数间抽。以产量不变为前提,无拐点井根据液面恢复速度确定停机时间,不同参数条件下的沉没度、泵效,计算启抽时间;有拐点井以拐点流压为基准,确定流压波动范围,从而得出对应启停时间。现场实施450口井,液面波动在50 m左右,系统效率提高5.27%,累计节电340.93×10^(4) kWh。基于液面变化规律制定的调大参数间抽制度,液面波动较小,节能效果好;同时利用不停机间抽技术能够实现短时、高频间抽,有效平衡产量与能耗的关系,节能潜力进一步释放,确保了油井高效举升,提高整体开发效益。

基于分布假设检验的风电机组静态偏航误差诊断方法研究

通过确定敏感风速区间并检测功率分布,实现对风电机组静态偏航误差值的估计。利用风电机组的实际运行数据对所提方法的有效性进行验证,并与基于功率曲线的诊断方法进行对比。结果表明,所提方法能够准确量化不同偏航误差区间的数据分布差异,精准识别出静态偏航误差所在的偏航角区间,诊断的准确性较高。

制导武器命中精度估计方法与检验方法一致性研究

针对制导武器命中精度估计方法和检验方法存在的联系以及原理性差异,对两种命中精度评定方法的一致性进行了研究。从双方风险角度研究了小子样条件对命中精度点估计和区间估计方法的影响,明确了提升命中精度评定准确性的手段;在分析命中精度指标与检验方法关系基础上,通过将双方风险与区间上界估计方法进行比较,明确了命中精度指标为备择假设的检验方法;从双方风险层面进一步分析了区间估计方法与检验方法的一致性。结果表明:对于区间估计方法和检验方法,通过合理调整置信水平参数和检出比参数,能够实现两种方法双方风险的一致性,但两种评定方法理论基础不同,进行精度评定会存在评定结论不一致的现象,该现象出现概率与制导武器自身精度有关。

异性结构面剪切特性及抗剪强度计算方法

天然结构面常存在两侧岩体岩性不一致的情况,对该类异性结构面抗剪特性进行研究有利于更全面地分析复杂地层中岩石的稳定性。首先,通过光学扫描技术获取天然结构面形貌点云数据并构建结构面网格模型;其次,将模型进行3维实体重构以浇筑多组含不同异性结构面的人工试样;然后,开展不同法向应力及剪切方向条件下的直剪试验;最后,通过有限差分仿真模拟软件FLAC3D进行数值模拟。基于JRC–JCS(joint roughness coefficient–joint wall compressive strength)结构面剪切模型,采用2维剖面法量化处理结构面粗糙度系数JRC,引入结构面组合壁面强度CJCS(combined joint wall compressive strength)及壁面强度系数比λ的概念以体现不同强度组合情况下的结构面抗剪特性差异。结果表明:数值模拟与直剪试验结果的规律性表征情况较为一致;在结构面单轴抗压强度较高或者较低一侧被确定时,强度较低侧对结构面峰值抗剪强度起主要的控制作用,强度较高侧则起到一定的增强作用,且壁面强度系数比λ对峰值抗剪强度的影响与法向应力的数值成正比。基于上述现象,利用相关函数对试验结果进行非线性曲面拟合,推导出一种表征不同岩石强度组合情况下的结构面峰值抗剪强度计算公式,并得出有效影响岩石结构面强度的强度比区间。该公式是对JRC–JCS模型的扩展且可在工程实践中广泛应用。

高速铁路联调联试工务数据管理与应用

以提升高速铁路联调联试工务专业试验数据归集、处理、分析自动化和智能化水平为目的,开展联调联试工务数据管理与应用技术研究,制定联调联试数据接口规范,研究提出试验数据综合分析应用系统功能设计、技术架构与部署方案。系统接入轨道、道岔、桥梁、隧道、路基等工务专业联调联试数据,实现数据集中管理和信息共享,提升了试验数据管理水平。基于历年试验数据,开展数据挖掘与智能分析,提供试验数据异常值判识、多维综合分析、试验报告自动生成等功能。

半成岩结构面原位直剪试验及抗剪参数的研究

半成岩作为一种特殊性岩土,工程性质受岩体结构面的影响较大,因此,确定结构面的剪切强度参数十分重要。文中根据半成岩原位剪切试验结果,采用概率统计分析方法,对抗剪强度参数进行估算,同时对M-C准则模型、B-B准则模型的95%预测区间和95%置信区间进行拟合及评价。结果表明,B-B准则模型的95%置信区间较M-C准则的范围更窄,参数估计的可靠性更高,尤其低法向应力水平下,B-B准则模型明显优于M-C准则模型,其抗剪强度参数更准确。

动态心电图QTc间期联合运动平板试验对冠心病心肌缺血的诊断价值分析

目的:探讨动态心电图QTc间期联合运动平板试验诊断冠心病心肌缺血的价值。方法:选取昆山市第一人民医院2019年1月—2022年12月收治的108例疑似冠心病心肌缺血患者,均行运动平板试验、动态心电图检查。以冠脉造影诊断结果为金标准,对比以上两种方法诊断冠心病心肌缺血的效能。结果:108例疑似冠心病心肌缺血患者经冠脉造影检查,阴性30例,占27.78%,阳性78例,占72.22%。动态心电图QTc间期诊断为阴性共有20例,阳性51例,运动平板试验诊断为阴性共有25例,阳性50例,动态心电图QTc间期联合运动平板试验,诊断为阴性共有29例,阳性62例。动态心电图QTc间期联合运动平板试验诊断冠心病心肌缺血的敏感度为79.49%,特异度为96.67%,准确度为84.26%,联合诊断的敏感度、准确度均高于动态心电图QTc间期、运动平板试验单一诊断,联合诊断的特异度高于动态心电图QTc间期单一诊断,差异均有统计学意义(P<0.05)。结论:与单一诊断相比,动态心电图QTc间期联合运动平板试验诊断冠心病心肌缺血的价值更高,可为临床诊断提供可靠的心电学依据。

基于bayes成功型试验模型的整车试验可靠度分析

为解决整车道路及耐久试验存在的试验成本高、样本量不统一、试验周期长、实验数据不够精确等实际问题,依据bayes成功型试验公式及Lipson变换公式,从置信度和可靠度方面分析试验样本量与可靠度、强化系数之间的关系,给出制定最优样本量、强度系数的理论方法.提出在某个置信区间内的可靠度及样本量的确定方案,实现了在设定置信区间及可靠度范围内的样本量最优解.对试验场耐久测试亦或公共道路试验的可靠性指标度量及样本量确定具有实际指导意义.