Journal articles: 'Test point optimal'

1

Evans, Merran A., and Maxwell L. King. "A point optimal test for heteroscedastic disturbances." Journal of Econometrics 27, no. 2 (February 1985): 163–78. http://dx.doi.org/10.1016/0304-4076(85)90085-5.

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King, Maxwell L. "A point optimal test for autoregressive disturbances." Journal of Econometrics 27, no. 1 (January 1985): 21–37. http://dx.doi.org/10.1016/0304-4076(85)90042-9.

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Vougas, Dimitrios V. "Modification of the point optimal unit root test." Applied Economics Letters 16, no. 4 (February 5, 2009): 349–52. http://dx.doi.org/10.1080/13504850601018635.

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Larner, Andrew J. "Defining ‘optimal’ test cut-off using global test metrics: evidence from a cognitive screening instrument." Neurodegenerative Disease Management 10, no. 4 (August 2020): 223–30. http://dx.doi.org/10.2217/nmt-2020-0003.

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Aim: To examine the variation of several global metrics of test accuracy with test cut-off for the diagnosis of dementia. These metrics included some based on the receiver operating characteristic curve, such as Youden index, and some independent of receiver operating characteristic curve, such as correct classification accuracy. Materials & methods: Data from a test accuracy study of Mini-Addenbrooke’s Cognitive Examination were used to calculate and plot each global measure against test cut-off. Results: Different ‘optimal’ cut-points were identified for the different global measures, with a spread of ten points in observed optimal cut-off in the 30-point Mini-Addenbrooke’s Cognitive Examination scale. Using these optima gave a large variation in test sensitivity from very high (diagnostic odds ratio) to very low (likelihood to be diagnosed or misdiagnosed), but all had high negative predictive value. Conclusion: The method used to determine the cut-off of cognitive screening instruments may have significant implications for test performance.

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King, Maxwell L. "A Point Optimal Test for Moving Average Regression Disturbances." Econometric Theory 1, no. 2 (August 1985): 211–22. http://dx.doi.org/10.1017/s0266466600011142.

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This paper reconsiders King's [12] locally optimal test procedure for first-order moving average disturbances in the linear regression model. It recommends two tests, one for problems involving positively correlated disturbances and one for negatively correlated disturbances. Both tests are most powerful invariant at a point in the alternative hypothesis parameter space that is determined by a function involving the sample size and the number of regressors. Selected bounds for the tests' significance points are tabulated and an empirical comparison of powers demonstrates the overall superiority of the new test for positively correlated moving average disturbances.

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Sofronov, G. Yu. "Asymptotically d-Optimal Test of a Change-Point Detection." Theory of Probability & Its Applications 46, no. 3 (January 2002): 547–48. http://dx.doi.org/10.1137/s0040585x97979160.

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Dastoor, Naorayex K., and Gordon Fisher. "On Point-Optimal Cox Tests." Econometric Theory 4, no. 1 (April 1988): 97–107. http://dx.doi.org/10.1017/s0266466600011889.

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This paper is concerned with the general problem of testing one form of covariance structure against another in a normal linear regression. It is shown that all the point-optimal tests recently proposed by King and his associates can be interpreted as special cases of a Cox test for non-nested hypotheses. This provides a synthesis of a whole range of point-optimal tests as well as demonstrating that King and his associates have exposed a class of Cox tests which have an exact distribution.

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Sofronov, G. Yu. "Asymptotically d-optimal Test of A Posteriori Change-Point Detection." Theory of Probability & Its Applications 49, no. 2 (January 2005): 367–71. http://dx.doi.org/10.1137/s0040585x97981111.

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Tang, Xiaofeng, Aiqiang Xu, and Shuangcheng Niu. "KKCV-GA-Based Method for Optimal Analog Test Point Selection." IEEE Transactions on Instrumentation and Measurement 66, no. 1 (January 2017): 24–32. http://dx.doi.org/10.1109/tim.2016.2614752.

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Gao, Yuan, Chenglin Yang, Shulin Tian, and Fang Chen. "Entropy Based Test Point Evaluation and Selection Method for Analog Circuit Fault Diagnosis." Mathematical Problems in Engineering 2014 (2014): 1–16. http://dx.doi.org/10.1155/2014/259430.

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By simplifying tolerance problem and treating faulty voltages on different test points as independent variables, integer-coded table technique is proposed to simplify the test point selection process. Usually, simplifying tolerance problem may induce a wrong solution while the independence assumption will result in over conservative result. To address these problems, the tolerance problem is thoroughly considered in this paper, and dependency relationship between different test points is considered at the same time. A heuristic graph search method is proposed to facilitate the test point selection process. First, the information theoretic concept of entropy is used to evaluate the optimality of test point. The entropy is calculated by using the ambiguous sets and faulty voltage distribution, determined by component tolerance. Second, the selected optimal test point is used to expand current graph node by using dependence relationship between the test point and graph node. Simulated results indicate that the proposed method more accurately finds the optimal set of test points than other methods; therefore, it is a good solution to minimize the size of the test point set. To simplify and clarify the proposed method, only catastrophic and some specific parametric faults are discussed in this paper.

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Duan, Xiu Sheng, Sheng Jun Li, Jing Xiao, and Jie Wang. "Optimal Selection Method of Test Points on Circuit Board Level." Advanced Materials Research 1006-1007 (August 2014): 1125–28. http://dx.doi.org/10.4028/www.scientific.net/amr.1006-1007.1125.

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Test point selection is the basic problem of fault diagnosis systems. It is also one of the key links in designing the condition monitoring system. Aiming at the optimizing the test points on circuit board level, an optimal selection method is proposed. It is the method which combines the SVM algorithm and the feature selection method. The principle and process of the method are discussed in detail and in the fault diagnosis experiment of a circuit board, the effectiveness is verified finally.

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Sriananthakumar, Sivagowry, and Maxwell L. King. "A new approximate point optimal test of a composite null hypothesis." Journal of Econometrics 130, no. 1 (January 2006): 101–22. http://dx.doi.org/10.1016/j.jeconom.2004.08.020.

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Aza�s, F., M. Lubaszewski, P. Nouet, and M. Renovell. "A Strategy for Optimal Test Point Insertion in Analog Cascaded Filters." Journal of Electronic Testing 21, no. 1 (February 2005): 9–16. http://dx.doi.org/10.1007/s10836-005-5283-x.

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14

Linnet, K., and E. Brandt. "Assessing diagnostic tests once an optimal cutoff point has been selected." Clinical Chemistry 32, no. 7 (July 1, 1986): 1341–46. http://dx.doi.org/10.1093/clinchem/32.7.1341.

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Abstract The specificity and sensitivity of a quantitative diagnostic test depends on the chosen cutoff point. The common practice of selecting a cutoff point that maximizes the specificity plus the sensitivity, as judged from the observed test results, is studied here by simulation. Test performance is on average assessed too optimistically by this procedure--a phenomenon of importance when sample sizes are small. For example, the average positive bias is up to 15% of the test performance for sample sizes of 25. Furthermore, binomial calculated standard errors of specificity and sensitivity estimates are incorrect. A Monte Carlo statistical method--the "bootstrap procedure"--is applied to correct for bias and to estimate standard errors, including the standard error of the optimal cutoff point. Independent and paired comparisons of two diagnostic tests are also considered when optimal cutoff points have been selected. For this purpose, binomial statistical tests behave satisfactorily. Examples of power functions are presented.

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Yokota, Hirotake, Naofumi Otsuru, Rie Kikuchi, Rinako Suzuki, Sho Kojima, Kei Saito, Shota Miyaguchi, Yasuto Inukai, and Hideaki Onishi. "Establishment of optimal two-point discrimination test method and consideration of reproducibility." Neuroscience Letters 714 (January 2020): 134525. http://dx.doi.org/10.1016/j.neulet.2019.134525.

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Hao, Jianqiang, Jianzhi Sun, Yi Chen, Qiang Cai, and Li Tan. "Optimal Reliable Point-in-Polygon Test and Differential Coding Boolean Operations on Polygons." Symmetry 10, no. 10 (October 11, 2018): 477. http://dx.doi.org/10.3390/sym10100477.

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This paper provides a full theoretical and experimental analysis of a serial algorithm for the point-in-polygon test, which requires less running time than previous algorithms and can handle all degenerate cases. The serial algorithm can quickly determine whether a point is inside or outside a polygon and accurately determine the contours of input polygon. It describes all degenerate cases and simultaneously provides a corresponding solution to each degenerate case to ensure the stability and reliability. This also creates the prerequisites and basis for our novel boolean operations algorithm that inherits all the benefits of the serial algorithm. Using geometric probability and straight-line equation F ( P ) = ( y i − y i + 1 ) ( x p − x i ) − ( y i − y p ) ( x i + 1 − x i ) , it optimizes our two algorithms that avoid the division operation and do not need to compute any intersection points. Our algorithms are applicable to any polygon that may be self-intersecting or with holes nested to any level of depth. They do not have to sort the vertices clockwise or counterclockwise beforehand. Consequently, they process all edges one by one in any order for input polygons. This allows a parallel implementation of each algorithm to be made very easily. We also prove several theorems guaranteeing the correctness of algorithms. To speed up the operations, we assign each vector a number code and derive two iterative formulas using differential calculus. However, the experimental results as well as the theoretical proof show that our serial algorithm for the point-in-polygon test is optimal and the time complexities of all algorithms are linear. Our methods can be extended to three-dimensional space, in particular, they can be applied to 3D printing to improve its performance.

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17

Danninger, Gabriele, and Walter J. Gutjahr. "Test Point Optimization in a Branching-Process-Based Reliability Model." Probability in the Engineering and Informational Sciences 8, no. 4 (October 1994): 591–609. http://dx.doi.org/10.1017/s0269964800003636.

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We describe a model for a random failure set in a fixed interval of the real line. (Failure sets are considered in input-domain-based theories of software reliability.) The model is based on an extended binary splitting process. Within the described model, we investigate the problem of how to select k test points such that the probability of finding at least one point of the failure set is maximized. It turns out that for values k > 2, the objective functions to be maximized are closely related to solutions of the Poisson-Euler-Darboux partial differential equation. Optimal test points are determined for arbitrary k in an asymptotic case where the failure set is, in a certain sense, “small” and “intricate,” which is the relevant case for practical applications.

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18

Kurozumi, Eiji. "Some Properties of the Point Optimal Invariant Test for the Constancy of Parameters." JOURNAL OF THE JAPAN STATISTICAL SOCIETY 33, no. 2 (2003): 169–80. http://dx.doi.org/10.14490/jjss.33.169.

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19

Itoh, Masato, Ken Takahashi, Hiroshi Nishida, Kiyonobu Sakagami, and Toshiteru Okubo. "Estimation of the Optimal Cut Off Point in a New Immunological Faecal Occult Blood Test in a Corporate Colorectal Cancer Screening Programme." Journal of Medical Screening 3, no. 2 (June 1996): 66–71. http://dx.doi.org/10.1177/096914139600300204.

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Objective –To estimate the optimal cut off point in a new immunological method (OC-Hemodia®) for faecal occult blood testing (FOBT). Setting –A corporate colorectal cancer screening programme in Japan. Method –The screening programme targeted colorectal cancer and adenomatous polyps ≥ 10 mm, and was conducted on 27 860 participants (age ⩾ 40) during 1991–92. The follow up consisted of diagnostic management by total colonoscopy on positive screened subjects exceeding the manufacturer recommended cut off level of 50 ng/ml faecal haemoglobin, and the identification of false negative cases by health insurance claims. The optimal cut off point was estimated by the positive predictive value, receiver operating characteristic (ROC) curve, and a cost effectiveness analysis. In this study evaluation was carried out only for cancer as the target disease. Results –At the current cut off level of 50 ng/ml the sensitivity and specificity were 86.5% and 94.9%. When the optimal cut off point was estimated the highest positive predictive value was obtained at 250–350 ng/ml. The ROC curve showed that the sum of sensitivity and specificity is maximised at 50 ng/ml, but evaluation of the ratio, change in sensitivity/change in false positive rate, pointed to higher optimal cut off points, showing marked changes occurring at about 200 ng/ml. The average cost per case was lowest at 250–300 ng/ml. Overall, the optimal cut off point was estimated to be about 200 ng/ml, at which the sensitivity and specificity of the test would be 77.5% and 98.9%, respectively. Conclusion –The optimal cut off point of the new immunological method of FOBT was estimated to be about 200 ng/ml, a value which, more than the current cut off value, favours specificity over sensitivity.

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20

Wang, Hong-Xia, Xiao-Hui Ye, and Liang Wang. "Research on optimizing the fault diagnosis strategy of complex electronic equipment." Computer Science and Information Systems 7, no. 1 (2010): 223–30. http://dx.doi.org/10.2298/csis1001223w.

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Diagnosis strategy is a testing sequence of the fault detection and isolation. For the distribution of the electronic equipment, a feasible engineering maintenance method is put forward based on the questions of test point selection and diagnosis strategy. The concepts of local diagnosis strategy and global diagnosis strategy are introduced. From which the local optimal diagnosis strategy is determined when the local optimal test points have been introduced by using the test information entropy, furthermore, the global optimal diagnosis strategy is determined by coalescing the local optimal diagnosis strategies. At last, the validity of the method is illustrated by an example from which the conclusion can be drawn that it is an optimal diagnosis strategy and the complexity of computation can be reduced.

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Ramsay, James, Marie Wiberg, and Juan Li. "Full Information Optimal Scoring." Journal of Educational and Behavioral Statistics 45, no. 3 (November 10, 2019): 297–315. http://dx.doi.org/10.3102/1076998619885636.

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Ramsay and Wiberg used a new version of item response theory that represents test performance over nonnegative closed intervals such as [0, 100] or [0, n] and demonstrated that optimal scoring of binary test data yielded substantial improvements in point-wise root-mean-squared error and bias over number right or sum scoring. We extend these results by showing that optimal scoring of the full information in option choices produces about as much further improvement in these measures of score performance as was achieved by going from sum scoring to optimal binary scoring.

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Huang, Liang, Jianjun Hou, Ying Liu, and Zhaohong Li. "Algorithm of selecting optimal test point for analog circuit based on grey relational entropy." JOURNAL OF ELECTRONIC MEASUREMENT AND INSTRUMENT 2009, no. 9 (December 17, 2009): 27–32. http://dx.doi.org/10.3724/sp.j.1187.2009.09027.

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Saikkonen, Pentti, and Ritva Luukkonen. "Point Optimal Tests for Testing the Order of Differencing in ARIMA Models." Econometric Theory 9, no. 3 (June 1993): 343–62. http://dx.doi.org/10.1017/s0266466600007702.

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Deciding the order of differencing is an important part in the specification of an autoregressive integrated moving average (ARIMA) mode. In most, though not all, cases this means deciding whether to use the original observations or their first differences. Common test procedures used in this context are some variants of autoregressive unit root tests. In these tests, one tests the null hypothesis that the order of differencing is one against the alternative that it is zero. The null hypothesis thus states that the original series is nonstationary and integrated of order one, whereas the alternative assumes that it is stationary. In this paper the situation is reversed so that our null hypothesis states that the original series is stationary, whereas the alternative states that it is integrated of order one. In our approach the use of a differenced series thus means overdifferencing and, consequently, a model with a moving average unit root. Testing for this moving average unit root is the topic of this paper. As discussed by Saikkonen and Luukkonen [26] and Tanaka [31], test procedures obtained for this null hypothesis can also be used to test the null hypothesis that a multivariate time series is cointegrated with a given theoretical cointegrating vector. Since the null hypothesis of cointegration is often of interest and cannot be naturally tested by autoregressive unit root tests, this connection provides an important motivation for the test procedures of this paper.

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Quan, Hui, Ying Guo, Rennian Li, Qingmiao Su, and Yi Chai. "Optimization design and experimental study of vortex pump based on orthogonal test." Science Progress 103, no. 1 (October 20, 2019): 003685041988188. http://dx.doi.org/10.1177/0036850419881883.

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To study the effects of the performance of different types of impeller on the vortex pump, orthogonal test design, which is carried out by combining experimental test and numerical calculation, is adopted to optimize the type of design structure for the impeller in vortex pump. To find out the folding blade angle, the position of the folding point in the whole blade, and whether to wedge folding blade, an orthogonal test scheme with three factors and two levels is designed. A numerical simulation test is conducted for each scheme by analyzing the performance curve of orthogonal test plan to find the optimal performance of the program and analyzing the test data of each scheme to obtain the primary and secondary orders of the impact performance in the angle of folding blades of the vortex pump, the position of folding point of blades, and the wedge shape of blades. The results show that the optical blade type combination is the blade angle R30F60, the folding point is at 2/3 of the whole blade, and the blade does not adopt radial wedge. The optimal combination scheme is 36% higher than the design value at the rated flow head, the efficiency is 18.75% higher than the design value, the high-efficiency zone of the vortex pump is wider, and the performance meets the design requirements. Through orthogonal experimental design, the design cycle of vortex pump can be shortened effectively, the design level of vortex pump can be improved, and the hydraulic model with superior performance can be obtained.

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Mauro, Marina, Vladimir Radovic, Melanie Wolfe, Markad Kamath, Premsyl Bercik, and David Armstrong. "13C Urea Breath Test forHelicobacter pylori: Evaluation of 10-minute Breath Collection." Canadian Journal of Gastroenterology 20, no. 12 (2006): 775–78. http://dx.doi.org/10.1155/2006/749453.

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AIM: To determine whether a shortened13C urea breath test (13C UBT) (breath collection time of 10 min) is as reliable as the standard assay (30 min).METHODS: Two hundred ninety-seven patients (mean ± SD: 53±16 years, 57% female) completed a13C UBT. Breath samples were obtained at baseline and at 5 min intervals up to 30 min. Sixty-seven patients also underwent endoscopic biopsy. Cluster analysis was performed on the13C UBT data to determine the optimal cut-off point at each time interval. Sensitivity and specificity of the13C UBT at all intervals compared with histology and culture and against the standard 30 min interval were determined.RESULTS: The calculated optimal cut-off points for each time interval (T), expressed as delta over baseline (δ‰), were 3.29 δ‰ at T5, 3.15 δ‰ at T10, 3.42 δ‰ at T15, 3.17 δ‰ at T20, 2.99 δ‰ at T25and 2.82 δ ‰ at T30. Except at T5, the risk of false-positive and false-negative test results at each time interval was lower than 2.3% using these cut-off points. When replacing the cut-off points with 3.0 δ‰, the risk of error was still lower than 2.3%. The test at T10showed 98.6% sensitivity and 98.6% specificity compared with T30. T10and T30showed 100% sensitivity and 96% specificity compared with histology and culture.CONCLUSIONS: The13C UBT is an accurate, noninvasive test, even when the breath sample interval is reduced to 10 min. The present study confirms the validity of a cut-off point of 3.0 δ‰ for the 10 min and 30 min13C UBT.

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Mauro, Marina, Vladimir Radovic, Pengfei Zhou, Melanie Wolfe, Markad Kamath, Premsyl Bercik, Ken Croitoru, and David Armstrong. "13C Urea Breath Test for Helicobacter pylori: Determination of the Optimal Cut-Off Point in a Canadian Community Population." Canadian Journal of Gastroenterology 20, no. 12 (2006): 770–74. http://dx.doi.org/10.1155/2006/472837.

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AIM: To determine the test characteristics and the optimal cut-off point for the 13C urea breath test (13C UBT) in a Canadian community laboratory setting.METHODS: Of 2232 patients (mean age ± SD: 51±21 years, 56% female) who completed a 13C UBT, 1209 were tested to evaluate the primary diagnosis of Helicobacter pylori infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the 13C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the 13C UBT against histology and microbiology using the calculated cut-off point.RESULTS: The calculated cut-off points were 3.09 δ‰ for the whole study population (n=2232), 3.09 δ‰ for the diagnosis group (n=1209) and 2.88 δ‰ for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 δ‰, the risk of false-positive and false-negative results was lower than 2.3%. The 13C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active H pylori infection.CONCLUSIONS: The 13C UBT is an accurate, noninvasive test for the diagnosis of H pylori infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cutoff point of 3.0 δ‰ for the 13C UBT when used in a large Canadian community population according to a standard protocol.

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McCabe, Brendan P. M., and Christopher L. Skeels. "Distributions You Can Count On …But What’s the Point?" Econometrics 8, no. 1 (March 4, 2020): 9. http://dx.doi.org/10.3390/econometrics8010009.

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The Poisson regression model remains an important tool in the econometric analysis of count data. In a pioneering contribution to the econometric analysis of such models, Lung-Fei Lee presented a specification test for a Poisson model against a broad class of discrete distributions sometimes called the Katz family. Two members of this alternative class are the binomial and negative binomial distributions, which are commonly used with count data to allow for under- and over-dispersion, respectively. In this paper we explore the structure of other distributions within the class and their suitability as alternatives to the Poisson model. Potential difficulties with the Katz likelihood leads us to investigate a class of point optimal tests of the Poisson assumption against the alternative of over-dispersion in both the regression and intercept only cases. In a simulation study, we compare score tests of ‘Poisson-ness’ with various point optimal tests, based on the Katz family, and conclude that it is possible to choose a point optimal test which is better in the intercept only case, although the nuisance parameters arising in the regression case are problematic. One possible cause is poor choice of the point at which to optimize. Consequently, we explore the use of Hellinger distance to aid this choice. Ultimately we conclude that score tests remain the most practical approach to testing for over-dispersion in this context.

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Smith, Michelle L. Depoy, and William S. Griffith. "Scan Start-Up Demonstration Test." International Journal of Reliability, Quality and Safety Engineering 22, no. 03 (June 2015): 1550014. http://dx.doi.org/10.1142/s021853931550014x.

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The CSTF and TSTF binary start-up demonstration tests have been studied in the literature. It has been shown that both tests perform optimal for various situations but neither one is an overall best test. Therefore, we propose a new demonstration test that is a compromise between the CSTF and TSTF start-up demonstration tests. The practitioner would accept the equipment if a cluster of successes occur prior to a preset number of failures, and rejection otherwise. Markov chains are used in the probabilistic analysis and this is extended to the non-i.i.d. case. Point and interval estimation is studied.

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Magder, L. "Optimal choice of a cut point for a quantitative diagnostic test performed for research purposes." Journal of Clinical Epidemiology 56, no. 10 (October 2003): 956–62. http://dx.doi.org/10.1016/s0895-4356(03)00153-7.

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Min, Li, Yang Xin, and Xiong Liyang. "POINT CLOUD ORIENTED SHOULDER LINE EXTRACTION IN LOESS HILLY AREA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 279–82. http://dx.doi.org/10.5194/isprsarchives-xli-b3-279-2016.

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Shoulder line is the significant line in hilly area of Loess Plateau in China, dividing the surface into positive and negative terrain (P-N terrains). Due to the point cloud vegetation removal methods of P-N terrains are different, there is an imperative need for shoulder line extraction. In this paper, we proposed an automatic shoulder line extraction method based on point cloud. The workflow is as below: (i) ground points were selected by using a grid filter in order to remove most of noisy points. (ii) Based on DEM interpolated by those ground points, slope was mapped and classified into two classes (P-N terrains), using Natural Break Classified method. (iii) The common boundary between two slopes is extracted as shoulder line candidate. (iv) Adjust the filter gird size and repeat step i-iii until the shoulder line candidate matches its real location. (v) Generate shoulder line of the whole area. Test area locates in Madigou, Jingbian County of Shaanxi Province, China. A total of 600 million points are acquired in the test area of 0.23km2, using Riegl VZ400 3D Laser Scanner in August 2014. Due to the limit Granted computing performance, the test area is divided into 60 blocks and 13 of them around the shoulder line were selected for filter grid size optimizing. The experiment result shows that the optimal filter grid size varies in diverse sample area, and a power function relation exists between filter grid size and point density. The optimal grid size was determined by above relation and shoulder lines of 60 blocks were then extracted. Comparing with the manual interpretation results, the accuracy of the whole result reaches 85%. This method can be applied to shoulder line extraction in hilly area, which is crucial for point cloud denoising and high accuracy DEM generation.

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Min, Li, Yang Xin, and Xiong Liyang. "POINT CLOUD ORIENTED SHOULDER LINE EXTRACTION IN LOESS HILLY AREA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (June 9, 2016): 279–82. http://dx.doi.org/10.5194/isprs-archives-xli-b3-279-2016.

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Shoulder line is the significant line in hilly area of Loess Plateau in China, dividing the surface into positive and negative terrain (P-N terrains). Due to the point cloud vegetation removal methods of P-N terrains are different, there is an imperative need for shoulder line extraction. In this paper, we proposed an automatic shoulder line extraction method based on point cloud. The workflow is as below: (i) ground points were selected by using a grid filter in order to remove most of noisy points. (ii) Based on DEM interpolated by those ground points, slope was mapped and classified into two classes (P-N terrains), using Natural Break Classified method. (iii) The common boundary between two slopes is extracted as shoulder line candidate. (iv) Adjust the filter gird size and repeat step i-iii until the shoulder line candidate matches its real location. (v) Generate shoulder line of the whole area. Test area locates in Madigou, Jingbian County of Shaanxi Province, China. A total of 600 million points are acquired in the test area of 0.23km2, using Riegl VZ400 3D Laser Scanner in August 2014. Due to the limit Granted computing performance, the test area is divided into 60 blocks and 13 of them around the shoulder line were selected for filter grid size optimizing. The experiment result shows that the optimal filter grid size varies in diverse sample area, and a power function relation exists between filter grid size and point density. The optimal grid size was determined by above relation and shoulder lines of 60 blocks were then extracted. Comparing with the manual interpretation results, the accuracy of the whole result reaches 85%. This method can be applied to shoulder line extraction in hilly area, which is crucial for point cloud denoising and high accuracy DEM generation.

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Chansareewittaya, Suppakarn. "Optimal Power Flow for Enhance TTC with Optimal Number of SVC by using Improved Hybrid TSSA." ECTI Transactions on Computer and Information Technology (ECTI-CIT) 13, no. 1 (May 4, 2019): 37–48. http://dx.doi.org/10.37936/ecti-cit.2019131.130978.

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In this paper, the hybrid tabu search and simulated annealing (TSSA) method are modified for improving. The main point of modification is to apply sine value into the value of the temperature of simulated annealing. This modification aims to reduce the disadvantage of the original hybrid TSSA. This disadvantage means the value of each parameter is only increased to the maximum value of the temperature of simulated annealing. The optimal number of flexible alternating current transmission system (FACTS) controller determining method is used to determine optimal number of FACTS. SVC is used as FACTS controller in this paper. The split search space method is integrated to manage search space of static var compensator (SVC) operating point. The allocations of SVCs are used to enhance total transfer capability (TTC). Test results on the IEEE 118-bus system and the practical Electricity Generating Authority of Thailand (EGAT) 58-bus system show that the proposed improved hybrid TSSA with optimal number determining method of SVC give higher TTC and less number of SVC than test results from evolutionary programming (EP) and original hybrid TSSA.

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Serrano González, Javier, Manuel Burgos Payán, Jesús Manuel Riquelme Santos, and Ángel Gaspar González Rodríguez. "Optimal Micro-Siting of Weathervaning Floating Wind Turbines." Energies 14, no. 4 (February 8, 2021): 886. http://dx.doi.org/10.3390/en14040886.

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This paper presents a novel tool for optimizing floating offshore wind farms based on weathervaning turbines. This solution is grounded on the ability of the assembly (wind turbine plus floater) to self-orientate into the wind direction, as this concept is allowed to freely pivot on a single point. This is a passive yaw potential solution for floating wind farms currently in the demonstration phase. A genetic algorithm is proposed for optimizing the levelised cost of energy by determining the geographical coordinates of the pivot points (i.e., the position over which the assembly can rotate to self-orient to the incoming wind direction). A tailored evaluation module is proposed to take into account the weathervaning motion around the pivot point depending on the incoming wind direction. The results obtained show the suitability of the proposed method to solve the addressed problem under realistic conditions. Additionally, the influence of the feasible region defined by the plot and the maximum area occupied on floating offshore wind farm design are also analysed in the proposed test cases. These deployable area constraints are of great importance for the viability of this technology, as it requires more space than classical solutions anchored to a fixed point.

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Alkan, Afra, Selcen Yüksel, and Pervin Demir. "Which of the favorite optimal cut-off determination methods is preferable for the ordinal response data? A simulation study." Proceedings of the International Conference on Applied Statistics 1, no. 1 (October 1, 2019): 1–7. http://dx.doi.org/10.2478/icas-2019-0001.

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Abstract The aim of this study is to investigate the performance of the optimal cut-off methods, which are generally used for the diagnostic tests with the continuous response, for the tests with the ordinal response. Diagnostic accuracy studies examine the ability of a diagnostic test to discriminate between the patients with and without the condition. For diagnostic tests with a continuous response, it is important in practice to calculate the optimal cut-off point that can differentiate patients and healthy individuals. There are many methods proposed in the literature to obtain the optimal cut-point value for continuous test results. The Youden index, the point closest-to-(0, 1) corner in the ROC plane approach, the concordance probability, and the minimum P-value approach are commonly used methods to determine optimal-cut-point. But the researches examining the performance of these methods in the setting of the ordinal response tests are lacking in the literature. So, we compared the mentioned optimal cut-off methods for the ordinal response data by the way of simulation design by considering the sample size and the balance of groups as simulation conditions. The sample sizes of the diseased and non-diseased group were set (50, 50), (100, 100), and (200, 200) for balanced design and (50, 100), (50, 150) and (50, 200) for unbalanced design. For each scenario, 1000 repeats were generated. The differences between the estimated and the true cut-off points (biases) were calculated. All these methods overestimated the true cut-off point, but the median biases of the methods were varying. For the unbalanced design, the same result was relevant but for the balanced design, the minimum P-value approach had a median bias as 0 while others have 1.

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Stasiuk, Galyna, Romana Piat, and Yuriy Sinchuk. "Optimal Elastic Design of CFCs." Key Engineering Materials 488-489 (September 2011): 295–98. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.295.

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The aim of the proposed studies is the development of the carbon/carbon composite with prescribed elastic properties. To achieve this, a microstructure optimisation problem for estimation of the microstructure with prescribed stiffness is formulated. The design variables of the posed problem are the local fibers distribution and porosity. The volume fractions of the fibers and pores in the whole microstructure are fixed. Material properties of the local microstructure of the composite are calculated using virtual models. Semi-analytical homogenization procedures were used for the development of these models. Modeling results are compared with elastic properties obtained experimentally by tension and compression test and ultrasonic studies of the bulk material. Approach to design microstructure for three point bending test is proposed.

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Li, Jian Guang, Wing Bun Lee, Chi Fai Cheung, Sandy To, J. J. Du, and Z. Q. Yin. "VSPDT: An Optimizer for Single Point Diamond Turning." Key Engineering Materials 339 (May 2007): 447–52. http://dx.doi.org/10.4028/www.scientific.net/kem.339.447.

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Virtual manufacturing (VM), which primarily aimed at reducing the lead times to market and costs associated with new product development, offers various test-beds for the time-consuming and expensive physical experimentation. Since surface roughness and form accuracy play essential roles in the functional performance of the products machined with ultra-precision machining technology. An optimizer, VSPDT (virtual single point diamond turning) system was developed for the purpose of form error compensation and optimal cutting parameters selection. In this paper, the keys issues for developing VSPDT using virtual manufacturing technology were highlighted such as framework of system, virtual workpiece, virtual machining and inspection, etc. At the end of the paper, A VSPDT was developed and applied to predict and compensate the form error, select optimal cutting parameters by using a 2-axis CNC ultra-precision turning machine.

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Awiakye-Marfo, George, Joseph Mung’atu, and Patrick O. Weke. "Randomised Pseudolikelihood Ratio Change Point Estimator in Garch Models." Journal of Mathematics 2020 (December 28, 2020): 1–12. http://dx.doi.org/10.1155/2020/6671515.

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In this paper, a randomised pseudolikelihood ratio change point estimator for GARCH model is presented. Derivation of a randomised change point estimator for the GARCH model and its consistency are given. Simulation results that support the validity of the estimator are also presented. It was observed that the randomised estimator outperforms the ordinary CUSUM of squares test, and it is optimal with large variance change ratios.

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Yang, Zhao Jun, Kai Fu Zhang, Yan Yan Ma, and Yuan Li. "Orthogonal Test Research on the Effect of Curing Technology on the Fatigue Life of Adhesive Bonding of CFRP and Aluminum Alloy." Advanced Materials Research 181-182 (January 2011): 534–39. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.534.

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The effect of curing pressure, curing temperature and curing time on the mechanical properties of the adhesively bonded composite structure of CFRP and Al are studied by means of the Orthogonal Test. Indexed by the fatigue life of the composite structure of CFRP and Al in room temperature environment and by making the direct, variance and effect analysis for the test data, we have obtained the optimal curing technology scheme within the test range. Because the optimal scheme isn’t included in the orthogonal table, we make the point estimation in order to get the fatigue life corresponding to this scheme. At last, the fatigue life under the optimal scheme is obtained by adding a test, the result of which is consistent with that of the theoretical analysis.The effect of curing pressure, curing temperature and curing time on the mechanical properties of the adhesively bonded composite structure of CFRP and Al are studied by means of the Orthogonal Test. Indexed by the fatigue life of the composite structure of CFRP and Al in room temperature environment and by making the direct, variance and effect analysis for the test data, we have obtained the optimal curing technology scheme within the test range. Because the optimal scheme isn’t included in the orthogonal table, we make the point estimation in order to get the fatigue life corresponding to this scheme. At last, the fatigue life under the optimal scheme is obtained by adding a test, the result of which is consistent with that of the theoretical analysis.

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Mion, Françcois, Gaëlle Rosner, Marina Rousseau, and Yves Minaire. "13C-Urea Breath Test for Helicobacter Pylori: Cut-off Point Determination by Cluster Analysis." Clinical Science 93, no. 1 (July 1, 1997): 3–6. http://dx.doi.org/10.1042/cs0930003.

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1. This study was performed on a large set of 13C-urea breath test results to determine the optimal cut-off point of the test for the diagnosis of Helicobacter pylori (Hp) infection. 2. The following steps were applied to three sets of urea breath test results obtained in three groups of subjects (696 adults before anti-Hp treatment, 1056 adults after anti-Hp treatment and 173 children under 17 years of age): (1) demonstrate the distribution of urea breath test results as a mix of two normal populations (Hp negative and Hp positive) by logarithmic transformation of the results in each group of subjects; (2) apply statistical cluster analysis to determine the separation point between Hp-negative and -positive populations; (3) calculate the mean and SD of each population, and use these parameters in the equation of the normal distribution to establish the frequency curves of Hp-negative and -positive populations; and (4) determine the cut-off point of the urea breath test as the intersection of the two curves, and the risks of error related to it. 3. The optimal cut-off point was found at +3.00 δ%0/00, with a risk of false-negative or -positive response of the urea breath test of less than 3%. From this, a cut-off point of +3.00 δ%0/00 for the 13C-urea breath test is recommended, with an indetermined zone between +2.5 and +3.5 δ0/00 to account for the spontaneous variation of 13CO2 in breath and the limits of GC—isotope ratio-MS analytical precision.

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Haas, Titus, Sascha Weikert, and Konrad Wegener. "MPCC-Based Set Point Optimisation for Machine Tools." International Journal of Automation Technology 13, no. 3 (May 5, 2019): 407–18. http://dx.doi.org/10.20965/ijat.2019.p0407.

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Numerical control code is typically used for manufacturing a workpiece using machine tools. Most state-of-the-art approaches decouple the set point optimisation into two steps: the geometry and the feed rate optimisation that does not necessarily result in time-optimal set points for the desired geometry. Given the originally programmed geometry through the numerical control code, dynamic constraints of the machine tool, and maximum permissible contour error for the optimisation, a model predictive contouring control based set point optimisation approach is developed to generate time-optimal set points for machine tools globally. A suitable error definition and its linearisation are used whereby the optimisation problem can be represented by a quadratic programming problem with linear constraints. Compared to most state-of-the-art methods, a direct approach is presented and no previous geometry optimisation step is required. Depending on the demands of accuracy, different maximum contour error constraints and penalisation as well as various maximum permissible axis velocities and accelerations are presented and tested on a test bench. The method is shown to be adaptable to different demands on the set points, and the contour errors can be affected by either the constraints or penalising factors.

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Jia, Xiaojuan, and Qi Ouyang. "Optimal Design of Point-Focusing Shear Vertical Wave Electromagnetic Ultrasonic Transducers Based on Orthogonal Test Method." IEEE Sensors Journal 18, no. 19 (October 1, 2018): 8064–73. http://dx.doi.org/10.1109/jsen.2018.2863546.

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Bisht, Dinesh C. S., and Pankaj Kumar Srivastava. "One Point Conventional Model to Optimize Trapezoidal Fuzzy Transportation Problem." International Journal of Mathematical, Engineering and Management Sciences 4, no. 5 (October 1, 2019): 1251–63. http://dx.doi.org/10.33889/ijmems.2019.4.5-099.

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This article puts forward a new one point approach to optimize trapezoidal fuzzy transportation problem. It proposes the method having point wise breakup of the trapezoidal number in such a way, that fuzzy transportation problem is converted into four crisp transportation problems. The method is equipped with minimum of supply and demand approach. In the end, the solutions are combined to construct the optimal solution. Modified distribution is applied on each crisp problem to develop optimal solution. The scheme presented is compared with competitive methods available in literature and it is found to be in good coordination with these. The scheme is equally good to be applied on unbalanced problems. Two numerical problems are considered to test the performance of the proposed approach.

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Koci, Lukas, Petr Munster, Tomas Horvath, Milan Cucka, and Miloslav Filka. "The Influence of Digital Modulations on 320 Gbit/s Optical Time Division Multiplexing." Journal of Communications Software and Systems 11, no. 4 (December 22, 2015): 187. http://dx.doi.org/10.24138/jcomss.v11i4.96.

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In this article the optical time division multiplexingtechnique for high speed point-to-point optical networksis discussed. We performed test of influence of selected types modulation formats in the optical time division multiplexing simulation model with a distance of 30 km. Additionally, this paper focuses on maximum bandwidth usage, improvement of bit error rate and the another goal is to achieve the maximal transmission distance by using of special compensation optical fiber. Optimal length of compensation optical fiber was found and used during simulations. We demonstrated positive influence compensation optical fiber on bit error rate. For comparisonof modulation formats such as return-to-zero, non-return-to-zero, chirped-return-to-zero, carrier-suppressed-return-to-zero, and m-ary quadrature amplitude modulation were tested. Our results confirm that it is possible to achieve better bit error rate for selected modulation formats.

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Christ, Michael, Felicitas Geier, Sabine Blaschke, Evangelos Giannitsis, Mehdi Khellaf, Johannes Mair, David Pariente, Volkher Scharnhorst, Veronique Semjonow, and Pierre Hausfater. "Clinical performance of a new point-of-care cardiac troponin I test." Clinical Chemistry and Laboratory Medicine (CCLM) 56, no. 8 (July 26, 2018): 1336–44. http://dx.doi.org/10.1515/cclm-2017-0693.

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Abstract Background: We evaluated the clinical performance of the Minicare cardiac troponin-I (cTnI), a new point-of-care (POC) cTnI test for the diagnosis of acute myocardial infarction (AMI) in a prospective, multicentre study (ISRCTN77371338). Methods: Of 474 patients (≥18 years) admitted to an emergency department (ED) or chest pain unit (CPU) with symptoms suggestive of acute coronary syndrome (ACS; ≤12 h from symptom onset), 465 were eligible. Minicare cTnI was tested immediately, 3 h and 6 h after presentation. AMI diagnoses were adjudicated independently based on current guidelines. Results: The diagnostic performance of the Minicare cTnI test at 3 h was similar for whole blood and in plasma: sensitivity 0.92 vs. 0.90; specificity 0.91 vs. 0.90; positive predictive value (PPV) 0.68 vs. 0.66; negative predictive value (NPV) 0.98 vs. 0.98; positive likelihood ratio (LR+) 10.18 vs. 9.41; negative likelihood ratio (LR–) 0.09 vs. 0.11. The optimal diagnostic performance was obtained at 3 h using cut-offs cTnI >43 ng/L plus cTnI change from admission ≥18.5 ng/L: sensitivity 0.90, specificity 0.96, PPV 0.81, NPV 0.98, and LR+ 21.54. The area under the receiver operating characteristics (ROC) curve for cTnI whole blood baseline value and absolute change after 3 h curve was 0.93. Conclusions: These data support the clinical usefulness of Minicare cTnI within a 0 h/3 h-blood sampling protocol supported by current guidelines for the evaluation of suspected ACS.

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Kim, Young Ik, and Young Hee Geum. "On Constructing Two-Point Optimal Fourth-Order Multiple-Root Finders with a Generic Error Corrector and Illustrating Their Dynamics." Discrete Dynamics in Nature and Society 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/378517.

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With an error corrector via principal branch of themth root of a function-to-function ratio, we propose optimal quartic-order multiple-root finders for nonlinear equations. The relevant optimal order satisfies Kung-Traub conjecture made in 1974. Numerical experiments performed for various test equations demonstrate convergence behavior agreeing with theory and the basins of attractions for several examples are presented.

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Machacek, John, and Shafiu Jibrin. "An Interior Point Method for Solving Semidefinite Programs Using Cutting Planes and Weighted Analytic Centers." Journal of Applied Mathematics 2012 (2012): 1–21. http://dx.doi.org/10.1155/2012/946893.

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We investigate solving semidefinite programs (SDPs) with an interior point method called SDP-CUT, which utilizes weighted analytic centers and cutting plane constraints. SDP-CUT iteratively refines the feasible region to achieve the optimal solution. The algorithm uses Newton’s method to compute the weighted analytic center. We investigate different stepsize determining techniques. We found that using Newton's method with exact line search is generally the best implementation of the algorithm. We have also compared our algorithm to the SDPT3 method and found that SDP-CUT initially gets into the neighborhood of the optimal solution in less iterations on all our test problems. SDP-CUT also took less iterations to reach optimality on many of the problems. However, SDPT3 required less iterations on most of the test problems and less time on all the problems. Some theoretical properties of the convergence of SDP-CUT are also discussed.

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Neto, Frederico Ribeiro, Rodrigo R. Gomes Costa, Jefferson R. Dorneles, Carlos W. Gonçalves, João H. C. L. Veloso, and Rodrigo L. Carregaro. "Handgrip Strength Cutoff Points for Functional Independence and Wheelchair Ability in Men With Spinal Cord Injury." Topics in Spinal Cord Injury Rehabilitation 27, no. 3 (August 13, 2021): 60–69. http://dx.doi.org/10.46292/sci20-00040.

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Objectives: To determine optimal handgrip strength (HGS) cutoff points for greater functional independence and wheelchair skills in men with spinal cord injury (SCI), and to establish predictive equations for functional independence and wheelchair ability in men with SCI, based on demographic characteristics, HGS, and functionality. Methods: In this cross-sectional study conducted at a rehabilitation hospital, 54 men with SCI were recruited and stratified into high and low paraplegia groups. All participants performed a maximum HGS test to determine cutoff points for the Spinal Cord Independence Measure (SCIM-III) and Adapted Manual Wheelchair Circuit (AMWC). The primary outcomes were the SCIM-III, AMWC, and HGS. Demographic characteristics obtained from participants’ electronic medical records were the secondary outcomes, used as predictor variables of functional independence. Results: The SCIM-III scale, performance score, and 3-minute overground wheeling test presented significant regression equations (R = 0.45, R = 0.69, and R = 0.72). The HGS showed a cutoff point of 102.5 kilogram force (kgf) to achieve a score of 70 on the SCIM-III and a 3-minute overground wheeling distance of 270 m. The HGS cutoff point to obtain a performance score of 23.7 seconds was 93.0 kgf. Conclusion: The HGS was a significant predictor for the SCIM-III score, AMWC performance score, and 3-minute overground wheeling test. Three significant predictive equations were established based on HGS. The cutoff points could be adopted as parameters for optimal functional independence and wheelchair skills.

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Wu, Shi Lin, Qi Zhang, and Jiu Long Xiong. "Optimizing the Design Parameters of Spherical-Cymbal Transducer Based on Comprehensive Point-Rating Method." Advanced Materials Research 301-303 (July 2011): 828–33. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.828.

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Spherical-cymbal transducer, which is derived from the traditional cymbal transducer, has demonstrated better vibration displacement and resonance frequency performance than the traditional cymbal transducer. In order to realize the optimal design of the spherical-cymbal transducer, orthogonal experiment is used to optimize the design parameters of the spherical-cymbal transducer. Weighted comprehensive point-rating method (WCPM) is used to process the orthogonal experiment results for multi indexes, and intuitionistic analysis of the weighted comprehensive score is used to optimize the level of each design parameter. The optimal combination of all design parameters is gained. Test results show that the optimized spherical-cymbal transducer has the best integrative performance.

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Thanassi, Wendy, Art Noda, Beatriz Hernandez, Jeffery Newell, Paul Terpeluk, David Marder, and Jerome A. Yesavage. "Delineating a Retesting Zone Using Receiver Operating Characteristic Analysis on Serial QuantiFERON Tuberculosis Test Results in US Healthcare Workers." Pulmonary Medicine 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/291294.

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Objective. To find a statistically significant separation point for the QuantiFERON Gold In-Tube (QFT) interferon gamma release assay that could define an optimal “retesting zone” for use in serially tested low-risk populations who have test “reversions” from initially positive to subsequently negative results.Method. Using receiver operating characteristic analysis (ROC) to analyze retrospective data collected from 3 major hospitals, we searched for predictors of reversion until statistically significant separation points were revealed. A confirmatory regression analysis was performed on an additional sample.Results. In 575 initially positive US healthcare workers (HCWs), 300 (52.2%) had reversions, while 275 (47.8%) had two sequential positive tests. The most statistically significant (Kappa = 0.48, chi-square = 131.0,P<0.001) separation point identified by the ROC for predicting reversion was the tuberculosis antigen minus-nil (TBag-nil) value at 1.11 International Units per milliliter (IU/mL). The second separation point was found at TBag-nil at 0.72 IU/mL (Kappa = 0.16, chi-square = 8.2,P<0.01). The model was validated by the regression analysis of 287 HCWs.Conclusion. Reversion likelihood increases as the TBag-nil approaches the manufacturer's cut-point of 0.35 IU/mL. The most statistically significant separation point between those who test repeatedly positive and those who revert is 1.11 IU/mL. Clinicians should retest low-risk individuals with initial QFT results < 1.11 IU/mL.

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García-Ramos, Amador, Alejandro Torrejón, Antonio J. Morales-Artacho, Alejandro Pérez-Castilla, and Slobodan Jaric. "Optimal Resistive Forces for Maximizing the Reliability of Leg Muscles’ Capacities Tested on a Cycle Ergometer." Journal of Applied Biomechanics 34, no. 1 (February 1, 2018): 47–52. http://dx.doi.org/10.1123/jab.2017-0056.

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This study determined the optimal resistive forces for testing muscle capacities through the standard cycle ergometer test (1 resistive force applied) and a recently developed 2-point method (2 resistive forces used for force-velocity modelling). Twenty-six men were tested twice on maximal sprints performed on a leg cycle ergometer against 5 flywheel resistive forces (R1–R5). The reliability of the cadence and maximum power measured against the 5 individual resistive forces, as well as the reliability of the force-velocity relationship parameters obtained from the selected 2-point methods (R1–R2, R1–R3, R1–R4, and R1–R5), were compared. The reliability of outcomes obtained from individual resistive forces was high except for R5. As a consequence, the combination of R1 (≈175 rpm) and R4 (≈110 rpm) provided the most reliable 2-point method (CV: 1.46%–4.04%; ICC: 0.89–0.96). Although the reliability of power capacity was similar for the R1–R4 2-point method (CV: 3.18%; ICC: 0.96) and the standard test (CV: 3.31%; ICC: 0.95), the 2-point method should be recommended because it also reveals maximum force and velocity capacities. Finally, we conclude that the 2-point method in cycling should be based on 2 distant resistive forces, but avoiding cadences below 110 rpm.

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Journal articles on the topic 'Test point optimal'

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