Accuracies of southwell and force/stiffness methods in the prediction of buckling strength of hypersonic aircraft wing tubular panels

Accuracies of the Southwell method and the force/stiffness (F/S) method are examined when the methods were used in the prediction of buckling loads of hypersonic aircraft wing tubular panels, based on nondestructive buckling test data. Various factors affecting the accuracies of the two methods were discussed. Effects of load cutoff point in the nondestructive buckling tests on the accuracies of the two methods were discussed in great detail. For the tubular panels under pure compression, the F/S method was found to give more accurate buckling load predictions than the Southwell method, which excessively overpredicts the buckling load. It was found that the Southwell method required a higher load cutoff point, as compared with the F/S method. In using the F/S method for predicting the buckling load of tubular panels under pure compression, the load cutoff point of approximately 50 percent of the critical load could give reasonably accurate predictions

Diagnostic value of the Dutch version of the MCclean Screening instrument for BPD (MSI-BPD)

Borderline personality disorder (BPD) often goes unrecognized, and therefore a short but accurate screening tool is desired. The present study investigated the psychometric properties of the 10-item McLean Screening Instrument for BPD (MSI-BPD) in 159 well-diagnosed female participants. The MSI-BPD showed excellent internal consistency (alpha = .90). When compared to BPD diagnoses based on a structured clinical interview (SCID-II), the MSI-BPD showed substantial congruent validity (receiver operating characteristic area under the curve = 0.96). The cutoff point proposed by the developers of the MSI-BPD (7 or more) showed high specificity (.96) and good sensitivity (.71). The optimal cutoff point in the present study (5 or more) showed somewhat lower specificity (.86), but importantly better sensitivity (.94). Taken together, the Dutch version of the MSI-BPD demonstrated good psychometric properties for a screening tool

On the boundedness of asymptotic stability regions for the stochastic theta method

The stochastic theta method gives a computational procedure for simulating ordinary stochastic differential equations. The method involves a free parameter, THgr. Here, we characterise the precise value of THgr beyond which the region of linear asymptotic stability of the method becomes unbounded. The cutoff point is seen to differ from that in the deterministic case. Computations that suggest further results are also given

Prostate-specific antigen and prostate-specific antigen density cutoff points among Indonesian population suspected for prostate cancer

PurposeRacial differences exist in the incidence of prostate cancer (PCa). Although many studies have looked at the performance of prostate-specific antigen (PSA) and PSA density (PSAD) in the detection of PCa, only a few have looked at it in relation to Indonesian men. The objective of this study is to find out better PSA and PSAD cutoff point in the detection of PCa in Indonesian men.MethodsA total of 404 consecutive Indonesian men underwent prostate biopsy for suspicion of PCa from 2008 to 2011. The biopsy criteria include one or more of the following: serum PSA more than 10 ng/mL, PSAD more than 0.15 if PSA 4–10 ng/mL, hypoechoic lesion during transrectal sonography and/or abnormal digital rectal examination.ResultsForty five out of 404 (11.1%) had positive biopsies. The mean age, prostate volume, PSA and PSAD were respectively 64.06 years, 43.03 mL, 45.59 ng/mL and 1.15. Of the 404, 131 cases (32.4%) were confirmed to be urinary retention. Positive urine culture found in 182 cases (45%). The cutoff point to detect PCa as estimated by the receiver operating characteristics was 6.95 ng/mL for PSA (sensitivity 97.8%, specificity 19.6%) and 0.7072 for PSAD (sensitivity 62.2%, specificity 78.7%). Positive predictive value for this PSA and PSAD cutoff point were 11.6% and 27.5% respectively (P=0.004 and P=0.000). There was a significant correlation between hypoechoic lesion and positive biopsy results (P=0.000). Urinary retention elevates PSA cutoff point to 14.55 (sensitivity 90.9%, specificity 50%), while positive urine culture alters almost no PSA cutoff elevation.ConclusionsPSA and PSAD cutoff point for Indonesian men in this series is relatively different from international consensus. Furthermore, these data show that PSA and PSAD cutoff point must be adjusted to racial variation to discriminate between malignant and benign disease. Urinary retention is a significant factor for PSA cutoff increase

Using the Chinese version of Memorial Delirium Assessment Scale to describe postoperative delirium after hip surgery

Objective:: Memorial Delirium Assessment Scale (MDAS) assesses severity of delirium. However, whether the MDAS can be used in a Chinese population is unknown. Moreover, the optimal postoperative MDAS cutoff point for describing postoperative delirium in Chinese remains largely to be determined. We therefore performed a pilot study to validate MDAS in the Chinese language and to determine the optimal postoperative MDAS cutoff point for delirium. Methods:: Eighty-two patients (80 ± 6 years, 21.9% male), who had hip surgery under general anesthesia, were enrolled. The Confusion Assessment Method (CAM) and Mini-Mental State Examination (MMSE) were administered to the patients before surgery. The CAM and MDAS were performed on the patients on the first, second and fourth postoperative days. The reliability and validity of the MDAS were determined. A receiver operating characteristic (ROC) curve was used to determine the optimal Chinese version MDAS cutoff point for the identification of delirium. Results:: The Chinese version of the MDAS had satisfactory internal consistency (α = 0.910). ROC analysis obtained an average optimal MDAS cutoff point of 7.5 in describing the CAM-defined postoperative delirium, with an area under the ROC of 0.990 (95% CI 0.977–1.000, P < 0.001). Conclusions:: The Chinese version of the MDAS had good reliability and validity. The patients whose postoperative Chinese version MDAS cutoff point score was 7.5 would likely have postoperative delirium. These results have established a system for a larger scale study in the future

Distress or no distress, that's the question: A cutoff point for distress in a working population

Background. The objective of the present study is to establish an optimal cutoff point for distress measured with the corresponding scale of the 4DSQ, using the prediction of sickness absence as a criterion. The cutoff point should result in a measure that can be used as a credible selection instrument for sickness absence in occupational health practice and in future studies on distress and mental disorders. Methods. Distress is measured using the Four Dimensional Symptom Questionnaire (4DSQ), a 50-item self-report questionnaire, in a working population with and without sickness absence due to distress. Sensitivity and specificity were compared for various potential cutoff points, and a receiver operating characteristics analysis was conducted. Results and conclusion. A distress cutoff point of 11 was defined. The choice was based on a challenging specificity and negative predictive value and indicates a distress level at which an employee is presumably at risk for subsequent sick leave on psychological grounds. The defined distress cutoff point is appropriate for use in occupational health practice and in studies of distress in working populations

Managing cutoff-based shipment promises for order fulfilment processes in warehousing

Warehouses recently face increasing stress imposed by a volatile customer demand and increasing customer expectations in terms of ever shorter order response times. In that respect, warehouses more and more offer same-day and next-day shipment conditions. However, same-day shipment promises are challenging to fulfil, especially as the order fulfilment process operates against fixed deadlines imposed by the predefined truck departure times. As a natural mitigation strategy, warehouses set a cutoff point and offer same-day shipment only to customers that order until the cutoff point, but next-day shipment to all customers ordering thereafter. Setting an appropriate cutoff point is challenging as it affects multiple facets of the service quality, such as the order response time and the service level. In this paper, we study the design of cutoff-based shipment promises for stochastic deadline-oriented order fulfilment processes in warehouses. We present a discrete-time Markov chain model for exact steady-state performance analysis and propose two novel performance measures – - and -cutoff service level – for service level measurement in these systems. We numerically show the benefit of cutoff-based shipment promises. Even with a late cutoff point, there is a significant gain in the system performance. Furthermore, we find that warehouses should set the cutoff point such that it balances customer expectations in terms of service level and order response time. Finally, warehouses can improve their shipment promises when referring to - instead of -cutoff service level and by implementing measures reducing the utilisation and the variabilities of the order fulfilment process

In Search of the Criterion Standard Test in Diagnostic Testing

Given a certain technology or procedure for diagnostic testing, different cutoff points produce different sensitivity and specificity rates. The cutoff point that generates highest sensitivity and specificity establishes the Criterion Standard Test (otherwise known as the Gold Standard Test). If, subject to good reason, a new testing technology or procedure emerges, the optimum cutoff point associated with it may generate higher sensitivity and specificity and thus a new improved Criterion Standard Test. Various cutoff selection methodologies have been proposed, all based on Euclidean geometry, involving the so-called Receiver Operating Characteristic (ROC) curve. Our purpose in this paper is to recommend a new selection methodology based on the P-Value associated with the well-known Pearson’s chi-squared test (χ2) – the conventional test utilized when testing for dependence between state of nature (disease present or not present) and evidence (test positive or negative measures). Using a hypothetical numerical example, we demonstrate that the cutoff point associated with the lowest P-Value of the Pearson’s chi-squared test is the one that maximizes sensitivity and specificity, or overall accuracy, thus establishing the Criterion Standard Test. Although the best geometric method (sums of squares) and the proposed method are equally effective in selecting the optimum cutoff point, only the proposed new procedure selects based on statistical significance. Additionally, we propose a simple theoretical benefits / costs linear setting to discuss the importance of net benefits associated with testing accuracy and reference harmful as well as beneficial testing cases found in various literature sources