The effect of retinal cryoapplication on the vitreous

Long-term clinical trials using bone mineral density (BMD) measurements are now commonplace. It is important to maintain a high standard of quality control. In this study two methods of monitoring quality control measurements of dual-energy X-ray absorptiometry (DXA) equipment have been compared using receiver operating curve (ROC) analysis: Shewhart multi-rule charts and Cusum charts. Computer-generated faults within daily spine phantom measurements were used. The Charts were then applied to 3 years of quality control data from one machine and the results related to hardware faults, random events and changes in the underlying BMD measurement. In the ROC analysis the Shewhart multi-rule chart performed as well or better than the cusum chart, but the stringency of the rules must be tightened to obtain optimal performance.     

一种带钢表面缺陷实时检测系统的研制及应用

提出了一种使用现场可编程门阵列(FPGA)实现有缺陷数据和无缺陷数据比较的带钢表面缺陷实时检测方法,克服了由于光源不均造成的错检;并通过系统的优化设计,降低了对数据通信和处理系统的性能要求, 提高了系统的性价比。     

Study on strip running deviation at exit of heat section in continuous annealing furnace for cold rolling

In order to solve strip reciprocating and quick- moving running deviation at the exit of heat section for vertical continuous annealing furnace, the thermal crown of furnace roller was analyzed quantitatively and regression method was used to determine the impact of roller crown on strip running deviation. And then the alarm program for strip running deviation was established, which can give early warning of strip running deviation and adjust the model parameter and the heating and cooling temperature rate simultaneously. With the application of this system on a continuous annealing machine for cold rolling in Shougang Jingtang Company, the strip running deviation which caused by thermal crown of furnace roller can be solved.     

Statistical evaluation of hearing screening by distortion product otoacoustic emissions

The aim of this study was to provide a statistical evaluation of the screening properties of distortion product otoacoustic emissions (DPOEs) in individuals with clinically normal hearing and in patients with pure sensorineural deafness of various degrees. The main informational parameters used were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the analysis of receiver operating characteristic (ROC) curves. For each frequency tested, ears were classified as a function of their audiometric threshold. Two groups were defined relative to an arbitrary reference, the "audiometric criterion." The PPV decreased and NPV increased with increases in the audiometric criterion. Each point of the ROC curve represents the relationship between the false alarm rate and the hit rate for each audiometric criterion ranging between 10 and 75 dB hearing level: the lower the audiometric criterion, the lower the hit rate value, and the lower the false alarm value. The audiometric criterion giving the highest hit rate and the lowest false alarm rate was 55 to 60 dB hearing level for primaries at 60 and 70 dB sound pressure level, or 25 to 30 dB hearing level for primaries at 30, 40, and 50 dB sound pressure level. These two different behaviors of ROC curves are consistent with the hypothesis that DPOEs do not represent activity at a single location along the basilar membrane.     

Measures and interpretations of vigilance performance: evidence against the detection criterion

Operators' performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure beta from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.     

重轨超声波随动探伤装置的研究与设计

由于铁路运输速度和载重的不断增长,对钢轨质量提出了越来越高的要求,在线超声波探伤成为生产高质量钢轨的必要手段。固定接触式超声波探伤装置与钢轨属于刚性接触,易磨损,探伤准确率低,针对这一缺点,提出了随动探伤设计理念,阐述了随动式超声波探伤装置的工作原理、结构组成及设备特点。该装置的应用大幅降低了超声波误判率和重轨在线检测成本。     

Minitab统计软件在化学检测实验室质量控制中的应用

利用Minitab统计软件可以直接从分析仪器及Excel导入或直接输入数据,设置相应参数,根据用户需要选择控制图类型,直接绘制各种质量控制图。本文简单介绍了休哈特控制图,根据化学检测实验室数据分别采用Minitab和Excel绘图并对其进行比较,发现Excel绘制控制图需要3 h,而采用Minitab绘制只需要15 min。使用Minitab易于操作,使质量控制变得更轻松简便,值得推广。     

Performance characteristics of rules for internal quality control: probabilities for false rejection and error detection

When assessing the performance of an internal quality control system, it is useful to determine the probability for false rejections (pfr) and the probability for error detection (ped). These performance characteristics are estimated here by use of a computer stimulation procedure. The control rules studied include those commonly employed with Shewhart-type control charts, a cumulative sum rule, and rules applicable when a series of control measurements are treated as a single control observation. The error situations studied include an increase in random error, a systematic shift, a systematic drift, and mixtures of these. The probability for error detection is very dependent on the number of control observations and the choice of control rules. No one rule is best for detecting all errors, thus combinations of rules are desirable. Some appropriate combinations are suggested and their performance characteristics are presented.     

露天矿山胶带运输系统保护装置的优化及应用

德兴铜矿铜厂采区利用BC01, BC02B, BC03等胶带机运输废石,胶带机能否安全稳定运行,是制约矿山高质量发展的重要因素。胶带系统在运行过程中,不可避免会遇到突发性故障,此时若胶带输送机未能及时停机,不仅会对设备造成一定程度的损坏,而且还有可能酿成较大的事故。为此,通过优化设计一种运输胶带斜式清扫器,解决了小块废石损伤胶带及滚筒的问题,实现了回程胶带小块废石清扫;采用移动胶带纠偏装置,解决了移动胶带易跑偏的难题,实现了移动胶带跑偏的自动调节;采用移动胶带驱动滚筒陶瓷包胶方式,有效降低了移动胶带打滑的故障率。胶带运输系统保护装置的优化与应用至关重要,可以解决废石胶带运输的安全运行瓶颈,实现废石胶带系统安全高效运行。     

A knowledge-based alarm system for monitoring cardiac operated patients--assessment of clinical performance

An intelligent alarm system for the postoperative monitoring of cardiac surgery patients, which did not require any manual data entries, was tested in two phases. A clinician monitored at bedside the patients' recovery and verified clinically abnormal physiological states. After the first test with ten patients, the system's rulebase was upgraded and then tested with an additional 15 patients. The alarm system employed two PC/ATs and was programmed to give notice of four pathological states (hyperdynamic state, hypovolemic state, hypoventilation and left ventricular failure) at two levels of urgency (alarm and alert levels). The monitoring lasted 5.4 +/- 1.7 hours per patient (mean +/- S.D.), totalling 134.7 hours. The system alarmed 27 times during the first and 73 times during the second phase of the testing. The sensitivity of the alarms was 100% in both phases, and the specificities increased from 20.0% to 73.9% and from 59.1% to 70.0% for the alarms and the alerts, respectively. This computerized decision support system based exclusively on data available in the automatically collected data base had a low false positive rate and gave early warnings about pathological states in the homogeneous group of adult postoperative cardiac patients.     

The technical design and performance of ultrafast computed tomography

The ultrafast radiograph CT scanner utilizes a scanning electron beam and semicircular tungsten targets to produce a moving radiograph source about the patient, thus eliminating mechanical motion within the gantry. This design allows scan times as short as 50 or 100 ms, as well as two levels of image resolution. The short scan time reduces the effects of motion blurring and artifacts and provides the ability to obtain high-quality images of dynamic processes and rapidly moving organs. When utilized in the SS (high-resolution) mode, the UFCT scanner provides contiguous image acquisition through a patient volume at rapid speeds, yet maintains image quality comparable with conventional CT scanners. This technology provides extremely short exposure times, rapid acquisition of multiple slices, continuous scanning without concern for anode heat storage and dissipation, and the ability to image moving organs or flowing contrast media. Many clinical applications exist that exploit these unique features.     

Proposed guidelines for the internal quality control of analytical results in the medical laboratory

The factors involved in analytical quality relate to definition of quality, creation of quality, and control of quality, and errors arise from external and internal sources as well as from permanent and variable factors. Further, the two main types of error are classified as systematic and random errors. Internal quality control (IQC) systems can only operate on the variable factors which are related to batch-to-batch variations (external factors) and to the performance in the laboratory (internal factors). In creating an adequate internal control system, several problems are faced: (i) quality of control materials, (ii) types and frequency of possible errors, (iii) number and types of control materials, (iv) number of replicates of the control, (v) probability of error detection, (vi) probability of false rejection, (vii) consequences of reject signals, (viii) trouble-shooting systems, and (ix) prevention of errors among many other conditions. Gaussian distributions of control results are assumed and the statistical control rules are evaluated in relation to probability of false rejections, Pfr, and probability of error detection, Ped, for the different rules. Combinations of low Pfr and high Ped are obtained by combining results from e.g. four measurements of the same control sample by use of mean and range rules. Further, it is not possible to establish a common control system which can be used for all quantities and analytical procedures; on the contrary, each procedure should have its particular efficient IQC system. These aspects are discussed and a number of guidelines for statistical control rules and problem related internal quality control are presented.     

Sex differences in monitoring performance.

220 male and 220 female undergraduates monitored a visual display for 1 hr. Although the results indicate females were poorer monitors, detecting 10% fewer signals and committing more false alarms, these sex differences accounted for only 4% of the variance of detection performance and less than 1% of the variance of the false alarm measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

高碳铬铁中硅的快速分析方法研究

采用氟硅酸钾滴定法测定高碳铬铁中的硅。试样用KOH和KNO3混合熔剂在镍坩埚中熔融,选取了最好的熔融条件,熔融温度600℃,熔融时间10 min。该条件下减少了对镍坩埚的损害,易于浸取。采用自制的抽滤装置,过滤速度快,滤纸无穿漏,吸附的残余酸量很少,易于洗涤和中和。样品平行测定的相对标准偏差在0.52%～3.67%,回收率实验结果为98.72%～101.30%。此方法快速简便,经大量生产实践检验,结果可靠,能够满足日常分析检测需要。     

Digital mammography: M-channel quadrature mirror filters (QMFs) for microcalcification extraction

Multiresolution methods are reported for feature extraction in breast cancer screening using digital mammography. The initial application is directed at the detection of microcalcification clusters (MCCs). Quadrature mirror filter (QMF) banks, using both two and three channel are proposed for the first time for both multiresolution decomposition and reconstruction. These filters are specifically tailored for automatic extraction of MCCs. The QMF multiresolution methods are compared to two channel tree structured wavelet transforms (TSWTs) methods previously reported. The QMF filters are preceded by an advanced tree structured nonlinear filter for noise suppression, prior to feature extraction, in order to minimize the false positive (FP) detection rate in digital mammography. The relative performance of these methods were evaluated using both simulated images and fifteen representative digitized mammograms containing biopsy proven microcalcification clusters. Similar high sensitivity (true positive (TP) detection rate (100%) and high specificity (0.6 average false positive (FP) MCC's/image) were observed, substantially better than more traditional approaches using single scale filters. The three channel QMF method, however, demonstrated better detail preservation of MCC's extracted compared to the two channel method. Detail preservation is important for the characterization of MCC's or individual microcalcifications in cancer screening.     

CT densitometry of the lungs: scanner performance

OBJECTIVE: Our goal was to establish the reproducibility and accuracy of the CT scanner in densitometry of the lungs. MATERIALS AND METHODS: Scanner stability was assessed by analysis of daily quality checks. Studies using a humanoid phantom and polyethylene foams for lung were performed to measure reproducibility and accuracy. The dependence of the CT-estimated density on reconstruction filter, zoom factor, slice thickness, table height, data truncation, and objects outside the scan field was determined. RESULTS: Stability of the system at air density was within approximately 1 HU and at water density within approximately 2 HU. Reproducibility and accuracy for densities found for lung were within 2-3%. Dependence on the acquisition and reconstruction parameters was neglible, with the exceptions of the ultra high resolution reconstruction algorithm in the case of emphysema, and objects outside the scan field. CONCLUSION: The performance of the CT scanner tested is quite adequate for densitometry of the lungs.     

A global activation approach to the effect of changes in environmental context on recognition.

A number of prior studies have not found declines in recognition performance when testing occurs in an environmental context that is different from the learning context. These findings raise serious problems for global activation theories of recognition which predict that hit and false alarm rates will decline when the test context does not match the learning context. Environmental context was manipulated as a unique combination of foreground color, background color, and location on a computer screen in 3 experiments using intact-rearranged recognition testing and 2 experiments using single-item testing. Changes in context resulted in reduced hit and false alarm rates as predicted by global activation theories in all 5 experiments. Mental reinstatement of the learning context was also examined. The results indicated that Ss did not use a mental reinstatement strategy in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于SE注意力机制的废钢分类评级方法

为了解决传统人工方法对废钢分类评级人为因素干扰大且效率低下等问题,提出基于挤压?激励（Squeeze?Excitation,SE）注意力机制构建废钢分类评级的深度学习网络模型,并对采集到的废钢卸载过程图像进行模型训练和验证。首先,搭建物理尺寸比例为1∶3废钢质量查验物理模型,采用高分辨率视觉传感器模拟采集货车卸载废钢作业场景下不同废钢的形貌特征;然后,对采集到的废钢图像使用跨阶段局部网络进行特征提取,利用空间金字塔结构解决特征丢失问题,采用注意力机制关注通道间的相关性;最后,在包含7个标签分类的两个数据集进行模型训练与验证。实验表明:该模型能够有效地对不同级别的废钢进行自动评级判定,全类别准确率达到83.7%,全类别平均精度为88.8%,在准确性方面相比于传统人工验质方法具有显著优势,解决了废钢入库过程中质量评价的公正性难题。      

An approach to general oncology: principles and procedures

53 patients clinically suspected of having a cerebellopontine angle (CPA) lesion were examined by computer tomography (CT) with 160 X 160 matrix EMI scanner. 17 cases (32%) had tumour positive CT, of which 12 were neurinomas and 1 meningioma. 1 CT suggestive of a CPA lesion was false positive and 1 unoperated case is probably a false negative CT. Three of the eleven verified neurinomas (27%) were of the medial type originating in the angle cistern. One neurinoma protruding 1 cm into the cistern showed no contrast enhancement. 2 CT scans (3.8%) were unsatisfactory due to movements and the large size of the head. CT is valuable for the investigation of CPA pathology and the diagnostic efficiency compares favourably to other neuroradiological procedures.     

基于深度学习的圆钢表面缺陷检测系统

圆钢表面缺陷是影响圆钢质量的重要因素。随着钢铁生产轧制节奏提升和智能化升级,人工检测、传统表面缺陷检测等方法已经难以同时满足多种类缺陷、高速在线检测等方面的需求。因此,设计了适用于圆钢表面缺陷检测的成像系统,提出分类优先网络与目标检测网络融合的圆钢表面缺陷检测方法,并将一种非缺陷样本加入网络模型的训练以提升检测精度。试验结果及应用效果表明,该方法针对凹坑、裂纹、耳子、划伤、翘皮等表面缺陷的准确识别率达到95.61%,能有效减少缺陷误报、漏报的问题。