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The study presents statistical procedures that monitor functioning of items over time. We propose generalized likelihood ratio tests that surveil multiple item parameters and implement with various sampling techniques to perform continuous or intermittent monitoring. The procedures examine stability of item parameters across time and inform compromise as soon as they identify significant parameter shift. The performance of the monitoring procedures was validated using simulated and real-assessment data. The empirical evaluation suggests that the proposed procedures perform adequately well in identifying the parameter drift. They showed satisfactory detection power and gave timely signals while regulating error rates reasonably low. The procedures also showed superior performance when compared with the existent methods. The empirical findings suggest that multivariate parametric monitoring can provide an efficient and powerful control tool for maintaining the quality of items. The procedures allow joint monitoring of multiple item parameters and achieve sufficient power using powerful likelihood-ratio tests. Based on the findings from the empirical experimentation, we suggest some practical strategies for performing online item monitoring. [ABSTRACT FROM AUTHOR]

Abstract Background The influenza surveillance has been received much attention in public health area. For the cases with excessive zeroes, the zero-inflated Poisson process is widely used. However, the traditional control charts based on zero-inflated Poisson model, ignore the association between influenza cases and risk factors, and thus may lead to unexpected mistakes when implementing monitoring charts. Method In this paper, we proposed risk-adjusted zero-inflated Poisson cumulative sum control charts, in which the risk factors were put to adjust the risk of influenza and the adjustment was made by zero-inflated Poisson regression. We respectively proposed the control chart monitoring the parameters individually and simultaneously. Results The performance of our proposed risk-adjusted zero-inflated Poisson cumulative sum control chart was evaluated and compared with the unadjusted standard cumulative sum control charts in simulation studies. The results show that for different distribution of impact factors and different coefficients, the risk-adjusted cumulative sum charts can generate much less false alarm than the standard ones. Finally, the influenza surveillance data from Hong Kong is used to illustrate the application of the proposed chart. Conclusions Our results suggest that the adjusted cumulative sum control chart we proposed is more accurate and credible than the unadjusted standard control charts because of the lower false alarm rate of the adjusted ones. Even the unadjusted control charts may signal a little faster than the adjusted ones, the alarm they raise may have low credibility since they also raise alarm frequently even the processes are in control. Thus we suggest using the risk-adjusted cumulative sum control charts to monitor the influenza surveillance data to alert accurately, credibly and relatively quickly.

Purpose: Laparoscopic totally extraperitoneal hernia repair (TEP) is a widely used treatment for inguinal hernia. Single-incision laparoscopic TEP (SILTEP) has attracted the attention of several surgeons, given its superior cosmetic results and patient satisfaction, as well as comparable outcomes to multiport surgery. Nonetheless, no relevant studies have evaluated the learning curve (LC) of SILTEP in terms of both operation time (OT) and surgical failure. Therefore, we aimed to investigate the LC of SILTEP for inguinal hernia. Methods: Medical records of 180 patients who underwent SILTEP performed by a single surgeon from a single institution between October 2012 and November 2017 were retrospectively reviewed. The LC was analyzed using the moving average method and cumulative sum control chart (CUSUM) for OT and surgical failure. Surgical failure was defined as the need for additional ports, open conversion, severe postoperative complications (Clavien–Dindo ≥ IIIa), and recurrence. Eight patients who underwent combined surgery or bilateral hernia repair were excluded from the OT analysis. Results: From CUSUM graphs, the study period was divided into three phases: OT-phases 1 (1st–32nd), 2 (33rd–83rd), and 3 (84th–172nd) for OT and failure-phases 1 (1st–29th), 2 (30th–58th), and 3 (59th–180th) for surgical failure. Mean OTs were statistically different in the three OT phases (64.6 vs. 50.8 vs. 35.2 min; p < 0.001). Open conversion (31.0% vs. 0% vs. 2.5%) and additional port insertion (6.9% vs. 24.1% vs. 2.5%) stabilized consecutively at failure-phases 2 and 3 (p < 0.001). Surgical failure rates decreased to 5.7% by failure-phase 3 (37.9% vs. 24.1% vs. 5.7%; p < 0.001). Conclusion: For an experienced laparoscopic surgeon, we estimated that approximately 60 cases are needed to overcome the LC for SILTEP in terms of both reducing OT and achieving a surgical failure rate < 10%. Further proficiency could be achieved after approximately 85 SILTEP procedures with a stable OT of approximately 35 min. [ABSTRACT FROM AUTHOR]

Cumulative sum (CUSUM) and change-point analysis (CPA) are two well-established statistical process control methods to detect changes in a sequence. Both have been used in psychometric research to detect aberrant responses in a response sequence, e.g., test speededness, inattentiveness, or cheating. However, the pros and cons of CUSUM and CPA in different testing settings still remain unclear. In this paper, we conduct a comprehensive comparison of the performance of twelve CUSUM-based statistics and three CPA-based procedures in detecting test speededness. Two speededness mechanisms are considered, namely the graduate change model (GCM) and the hybrid model (HM), to test the robustness and flexibility of the two methods. Simulation studies show that the performances of the statistics are affected by the underlying data generating model, the severity of speededness, and the test length. Generally, under HM some CUSUM statistics perform much better than the CPA-based statistics. Under the GCM, the performance of the CPA statistics is dramatically improved. Taken together, due to the unknown mechanism of speededness in real applications, two CUSUM-based statistics are recommended when the test length is long (e.g., 80 items), regardless of the underlying mechanism being HM or GCM. In a relatively short (e.g., 40 items) or medium-length (e.g., 60 items) test, no statistic always ends up in the top three under both HM and GCM. In those cases, either one of the two CUSUM-based statistics mentioned above can be a reasonable choice because of their good (though not necessarily the best) performance in a wide range of conditions. [ABSTRACT FROM AUTHOR]

In this research, we propose the new mixed control chart called the mixed Moving Average-Cumulative Sum (MA-CUSUM) control chart used for monitoring parameter changes in asymmetrical and symmetrical processes. Its efficiency was compared with that of the Shewhart, Cumulative Sum (CUSUM), Moving Average (MA), mixed Cumulative Sum-Moving Average (CUSUM-MA) and mixed Moving Average-Cumulative Sum (MA-CUSUM) control charts by using their average run lengths (ARLs), the standard deviation of the run length (SDRL), and median run length (MRL) via the Monte Carlo simulation (MC). The simulation results show that the MA-CUSUM control chart was more efficient than the other control charts for small-to-moderate parameter changes for all distributions tested. To compare their applicability to real-world situations, the control charts were applied to data for the River Nile flow from 1871–1930 and mine explosions in the UK from 1875–1951. It was found that the MACUSUM control chart could more quickly detect parameter changes than the other control charts. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: To assess hearing outcomes and complications of endoscopic stapes surgery by a single surgeon in a 10‐year period, to compare these data with conventional microscopic procedures by the same operator, and to describe the learning curve of endoscopic stapedotomy. Study Design: Retrospective study. Methods: This is a retrospective study on patients who underwent endoscopic stapes surgery performed by the same senior surgeon, experienced both in microscopic and endoscopic techniques, between January 2009 and December 2018. Audiological data were compared, and intraoperative and postoperative complications were collected. The surgeon's last 30 cases of microscopic stapedotomy were enrolled as the control group. The results of the first 100 endoscopic stapes surgeries were analyzed separately to create a cumulative sum (CUSUM) control chart for learning curve assessment. Results: One hundred seventy‐eight endoscopic and 30 microscopic stapes surgeries were included. In the endoscopic group, the mean postoperative air–bone gap was 8.2 dB. No significant differences between the endoscopic and microscopic preoperative and postoperative values were reported. A total of eight complications (4.5%) were observed in the endoscopic cohort, although in the control group, no complication occurred. The mean surgical time was 51.9 minutes in the endoscopic group versus 48.2 minutes in the microscopic group (P >.05). No association between stapedotomy success and the increasing number of procedures was found. Conclusions: Our article demonstrates that functional results from endoscopic stapes surgery are similar to those from microscopic stapes surgery in terms of both safety and efficacy. After gaining endoscopic experience, the surgical duration of stapes surgery will be adequate starting from the first cases. Level of Evidence: 4 Laryngoscope, 131:885–891, 2021 [ABSTRACT FROM AUTHOR]

Introduction. Electrical insulation systems make up about 0.03 % of the traction electric machines (TEM) mass, but they are of exceptional importance and affect the design capabilities and manufacturing techniques of electric machines, ultimately - on their specific weight and overall dimensions, on the reliability and durability of the TEM. Purpose. The monitoring of the stability of the manufacturing process of electrical insulating systems of the TEM based on the insulation resistance measurements. Methodology. The analysis of the manufacturing process is carried out for three versions of the case of insulation of the magnetic system of the DC traction electric motor. Practical value. Construction and analysis of special graphs (charts) of individual values and cumulative sums of insulation resistance, sliding range MR allow to find out whether the technological process of manufacturing electric insulating systems of traction electric machines is in a statistically controllable state.

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we propose a new methodology based on the combination of cumulative sum procedure and generalized likelihood ratio statistic for joint monitoring of the process location and dispersion. Then, we explore the effect of measurement errors on detecting ability of the proposed control chart when (i) the variance of measurement error is constant (ii) the variance of measurement error increases linearly as the level of the process mean increases. We also utilize multiple measurements on each sample point in order to decrease the adverse effects of measurement errors on the performance of the proposed control charts. Two numerical examples based on simulation studies are given to evaluate the ability of the proposed methods in terms of average run length, median run length, standard deviation of run length, and the first and third quantile points of the run length distribution ( Q1 and Q3). Finally, a real life example is given to illustrate the application of the proposed method. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Supersaturated designs are designs in which the number of factors exceeds the run size; consequently, there are not enough degrees of freedom to estimate all the main effects. The goal here is to identify the dominant factors that constitute a small proportion of the overall set of factors, according to the assumption of effect sparsity. The analysis of such designs constitutes a challenging task and, even though many methods have been proposed in the literature assuming a normal response, only few works attempted to address the case of non-normal responses. In this paper, we propose a method for screening out the most important features in supersaturated designs assuming a Bernoulli distributed response. This new approach is based on an effective chart in Statistical Process Control, the cumulative sum control chart, combined with an information theoretic measure, and it is referred as the MIC algorithm. We judge the value of MIC through comparisons with three existing approaches suggested in the literature: the least absolute shrinkage and selection operator penalization method, and two feature selection algorithms, the Conditional Mutual Information Maximization and the minimal-redundancy-maximal-relevance. The simulation study reveals that the proposed method can be considered an advantageous method because of its extremely good performance in terms of statistical power. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Copyright of Electrical Engineering & Electromechanics is the property of National Technical University, Kharkiv Polytechnic Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To explore the training ability of pad to guide the balance of soft tissue by drawing cumulative sum (CUSUM) control chart total knee arthroplasty (TKA) sensor., Methods: The data of 73 knees of TKA assisted by electronic gasket initially completed by a senior physician were analyzed retrospectively. There were 8 males (8 knees) and 52 females (65 knees), with an average age of (67.5±5.9) years (57-82 years). The balance of the internal and external space of knee joint was measured at 0°, 45°, 90°, and 120°, in order to observe the pressure distribution of the medial and la-teral compartments, and CUSUM learning curve was drawn., Results: In 0° extension, the medial pressure was higher than the lateral ( P < 0.01), when flexion began, the medial and lateral pressures decreased, and became stable and approximately equal during 45°-120°. In the learning curve, by knee 34, CUSUM 0° curve crossed the acceptable control line from above, which showed that it was easy to grasp the soft tissue balance at 0° position through sensor learning. CUSUM 45° curve was above the unacceptable control line in the end, which meant that it was difficult to grasp the technique at the mid-flexion angle. CUSUM 90° and 120° crossed the acceptable control line from above by knee 68 and 57 respectively, which showed that the technique of balance could be improved with the aid of more cases., Conclusion: The electronic pressure sensor can effectively guide the soft tissue balance in TKA. The learning process is simple and does not increase the risk of complications. It can be used as a tool for learning TKA soft tissue balance technology to guide joint surgeons to further master or improve the soft tissue balance technology.

Web service recommendation systems can help service users to locate the right service from the large number of available web services. Avoiding recommending dishonest or unsatisfactory services is a fundamental research problem in the design of web service recommendation systems. Reputation of web services is a widely-employed metric that determines whether the service should be recommended to a user. The service reputation score is usually calculated using feedback ratings provided by users. Although the reputation measurement of web service has been studied in the recent literature, existing malicious and subjective user feedback ratings often lead to a bias that degrades the performance of the service recommendation system. In this paper, we propose a novel reputation measurement approach for web service recommendations. We first detect malicious feedback ratings by adopting the cumulative sum control chart, and then we reduce the effect of subjective user feedback preferences employing the Pearson Correlation Coefficient. Moreover, in order to defend malicious feedback ratings, we propose a malicious feedback rating prevention scheme employing Bloom filtering to enhance the recommendation performance. Extensive experiments are conducted by employing a real feedback rating data set with 1.5 million web service invocation records. The experimental results show that our proposed measurement approach can reduce the deviation of the reputation measurement and enhance the success ratio of the web service recommendation. [ABSTRACT FROM PUBLISHER]

The cumulative sum (CUSUM) and the exponentially weighted moving average (EWMA) control charts are alternatives to the Xbar chart. The CUSUM's theoretical optimality suggests that it should outperform the EWMA for detecting persistent shifts, but practitioners have long thought that the two perform about equally. Each also involves design decisions on the likely shift in the process. This article quantifies the effect of these choices and concludes that, though the CUSUM outperforms the EWMA at the shift for which each was designed, if the actual shift is smaller than that used in the design, the EWMA may respond faster. [ABSTRACT FROM AUTHOR]

A cumulative sum control chart for multivariate Poisson distribution (MP-CUSUM) is proposed. The MP-CUSUM chart is constructed based on log-likelihood ratios with in-control parameters, Θ0, and shifts to be detected quickly, Θ1. The average run length (ARL) values are obtained using a Markov Chain-based method. Numerical experiments show that the MP-CUSUM chart is effective in detecting parameter shifts in terms of ARL. The MP-CUSUM chart with smaller Θ1is more sensitive than that with greater Θ1to smaller shifts, but more insensitive to greater shifts. A comparison shows that the proposed MP-CUSUM chart outperforms an existing MP chart. [ABSTRACT FROM PUBLISHER]

A time-weighted multivariate control chart for individual observations is introduced to monitor process variability changes in multiple quality characteristics in phase II applications. Because of adaptive adjustments, the proposed control chart is sensitive to total variation increase in a multivariate manufacturing process. A new visualization tool, named adaptive EWMS star glyphs, is proposed for process diagnosis once an out-of-control signal is found. An example is presented to illustrate the application of the proposed charting procedure. [ABSTRACT FROM AUTHOR]

Cumulative sum control charts (CUSUM) are constructed for controlling the parameters of the binomial distribution when the underlying distribution is Poisson. It is observed that the parameters of the V-mask and the Average Run Length (ARL) change considerably for a slight shift in the parameters (or ratio) of the distribution understudy. [ABSTRACT FROM AUTHOR]