Response prediction techniques and case studies of a path blocking system based on Global Transmissibility Direct Transmissibility method

2017 ◽  
Vol 388 ◽  
pp. 363-388 ◽  
Author(s):  
Zengwei Wang ◽  
Ping Zhu ◽  
Jianxuan Zhao
Keyword(s):  
Case Studies ◽  
Response Prediction ◽  
Prediction Techniques

Extreme Response Prediction of Steel Risers Using a Four Parameter Distribution

2017 ◽  
Author(s):  
Miguel Alfonso Calderon Ibarra ◽  
Fernando Jorge Mendes de Sousa ◽  
Luís Volnei Sudati Sagrilo ◽  
Ying Min Low
Keyword(s):  
Case Studies ◽  
Dynamic Behavior ◽  
Water Depth ◽  
Lognormal Distribution ◽  
Extreme Values ◽  
Extreme Value Distribution ◽  
Response Prediction ◽  
Parameter Distribution ◽  
Extreme Response ◽  
Hermite Transformation

Recently, a four-parameter distribution known as the shifted generalized lognormal distribution (SGLD) has been presented in the literature. One of its main advantages is that it covers regions of skewness-kurtosis not covered by other distributions of common use in engineering. In this paper, the performance of this distribution is evaluated in the extreme values’ estimation of the utilization ratios of steel riser sections. Three alternatives for using SGLD are investigated in two case studies of different dynamic behavior. The first one is a SLWR (steel-lazy wave riser) connected to a turret-moored FPSO in 914m water depth, and the second is a SLWR connected to a spread-mooring FPSO in a water depth of 1400m. The results obtained by the SGLD-based analysis, which considered several simulation lengths, are compared to those obtained by means of an extreme value distribution fitted to episodical extremes obtained from many distinct realizations. The results of a traditional Weibull-fitting approach to the response peaks and those obtained with and Hermite transformation-based model are also presented for comparison.

scholarly journals Increasing T-Method Accuracy Through Application of Robust M-Estimatior

2018 ◽  
Vol 7 (3.25) ◽  
pp. 44
Author(s):  
N Harudin ◽  
Jamaludin K R ◽  
M Nabil Muhtazaruddin ◽  
Ramlie F ◽  
S H Ismail ◽  
...  
Keyword(s):  
Sample Size ◽  
Case Studies ◽  
Prediction Accuracy ◽  
Study Data ◽  
Inverse Regression ◽  
Limited Sample ◽  
Limited Sample Size ◽  
Lower Accuracy ◽  
M Estimator ◽  
Prediction Techniques

Mahalanobis Taguchi System is an analytical tool involving classification, clustering as well as prediction techniques. T-Method which is part of it is a multivariate analysis technique designed mainly for prediction and optimization purposes. The good things about T-Method is that prediction is always possible even with limited sample size. In applying T-Method, the analyst is advised to clearly understand the trend and states of the data population since this method is good in dealing with limited sample size data but for higher samples or extremely high samples data it might have more things to ponder. T-Method is not being mentioned robust to the effect of outliers within it, so dealing with high sample data will put the prediction accuracy at risk. By incorporating outliers in overall data analysis, it may contribute to a non-normality state beside the entire classical methods breakdown. Considering the risk towards lower prediction accuracy, it is important to consider the risk of lower accuracy for the individual estimates so that the overall prediction accuracy will be increased. Dealing with that intention, there exist several robust parameters estimates such as M-estimator, that able to give good results even with the data contain or may not contain outliers in it. Generalized inverse regression estimator (GIR) also been used in this research as well as Ordinary Lease Square Method (OLS) as part of comparison study. Embedding these methods into T-Method individual estimates conditionally helps in enhancing the   accuracy of the T-Method while analyzing the robustness of T-method itself.  However, from the 3 main case studies been used within this analysis, it shows that T-Method contributed to a better and acceptable performance with error percentages range 2.5% ~ 22.8% between all cases compared to other methods. M-estimator is proved to be sensitive with data consist of leverage point in x-axis as well as data with limited sample size.   Referring to these 3 case studies only, it can be concluded that robust M-estimator is not feasible to be applied into T-Method as of now. Further enhance analysis is needed to encounter issues such as Airfoil noise case study data which T -method contributed to highest error% prediction.  Hence further analysis need to be done for better result review. 

Gearbox Noise Reduction: Prediction and Measurement of Mesh-Frequency Vibrations Within an Operating Helicopter Rotor-Drive Gearbox

1974 ◽  
Vol 96 (2) ◽  
pp. 567-577 ◽  
Author(s):  
R. H. Badgley ◽  
R. M. Hartman
Keyword(s):  
Noise Reduction ◽  
Analytical Methods ◽  
Response Prediction ◽  
Essential Elements ◽  
Rolling Element Bearing ◽  
Helicopter Rotor ◽  
Prediction Methods ◽  
Spectrum Prediction ◽  
Rotor Drive ◽  
Prediction Techniques

This paper presents correlations between analysis and test results for a complex mechanical system. While the paper is specificially concerned with a helicopter rotor-drive gearbox, the results and methods employed are general enough to be broadly applicable to gearboxes of all kinds. The development of gearbox noise reduction technology has been the objective of an extensive U. S. Army-supported program over the past five years. The gearbox noise problem has been recast as a mechanical vibrations problem, and detailed analytical methods have been developed to treat it. Gear excitation analyses, drive-train response analyses, and empirically-based acoustic spectrum prediction methods have been developed and published in considerable detail. Rolling-element bearing stiffness prediction methods and thin-shell vibration response prediction techniques have been shown to be essential elements in the procedure. In order to verify the analytical methods, a detailed and comprehensive test program was undertaken on a complete CH-47 forward-rotor-drive gearbox, operating under normal torque conditions in a test-cell environment. At the same time, predictions were made of quantities to be measured using the previously published analytical methods. Comparisons between predicted and measured quantities show reasonably good correlation, indicating that the analytical procedures are suitable for careful use in gearbox design or redesign efforts directed at vibration and noise reduction. Areas in which the analytical methods can be improved were also identified.

scholarly journals Geomechanical Hazards related to River Hydraulics and Remedial Measures: Selected Case Studies in India

2021 ◽  
Vol 16 ◽  
pp. 214-220
Author(s):  
Joydeep Dutta ◽  
Sudip Basack ◽  
Ghritartha Goswami ◽  
Bini Kiron
Keyword(s):  
Case Studies ◽  
Open Channel ◽  
Remedial Measures ◽  
Science And Engineering ◽  
River Hydraulics ◽  
North Eastern ◽  
Important Study ◽  
River Training ◽  
And Migration ◽  
Prediction Techniques

River science and engineering has been one of the important study areas for geologists, hydrologists and engineers. The open channel flow and associated hydraulics often initiate several geomechanical hazards including silting and scouring, meandering and migration, floods, etc. Such hazards may lead to disastrous consequences if adequate remedial measures are not undertaken by proper river training works. This paper presents selected case studies in northern and north-eastern parts of India where such hazards occurred due to migration of river channel and flooding of adjacent lands. The two study areas have been the Kosi and the Brahmaputra river basins. In the former study area, hazards took place due to eastward migration, whereas in the latter case, significant damages occurred due to scouring and erosion. The descriptions of the hazards occurred, and the mitigation techniques adopted have been briefly summarized in this paper. A critical analysis with prediction techniques for flood occurrence probability and erosion potential has been conducted as well. The relevant conclusions are drawn therefrom.

Corporate Sustainability: Challenge to Managerial Orthodoxies

2003 ◽  
Vol 9 (1) ◽  
pp. 2-11 ◽  
Author(s):  
Dexter Dunphy
Keyword(s):  
Case Studies ◽  
Corporate Sustainability ◽  
Central Place ◽  
Marked Contrast ◽  
Sustainability Management

ABSTRACTThis paper addresses the issue of corporate sustainability. It examines why achieving sustainability is becoming an increasingly vital issue for society and organisations, defines sustainability and then outlines a set of phases through which organisations can move to achieve increasing levels of sustainability. Case studies are presented of organisations at various phases indicating the benefits, for the organisation and its stakeholders, which can be made at each phase. Finally the paper argues that there is a marked contrast between the two competing philosophies of neo-conservatism (economic rationalism) and the emerging philosophy of sustainability. Management schools have been strongly influenced by economic rationalism, which underpins the traditional orthodoxies presented in such schools. Sustainability represents an urgent challenge for management schools to rethink these traditional orthodoxies and give sustainability a central place in the curriculum.

Short-Form Application of the Screening Test of Spanish Grammar and the Northwestern Syntax Screening Test to Latino Children

1978 ◽  
Vol 9 (4) ◽  
pp. 220-235
Author(s):  
David L. Ratusnik ◽  
Carol Melnick Ratusnik ◽  
Karen Sattinger
Keyword(s):  
New York ◽  
Case Studies ◽  
Metropolitan Area ◽  
Screening Test ◽  
Normative Data ◽  
Short Form ◽  
Latino Children ◽  
Data Application ◽  
York Metropolitan Area ◽  
Multiple Regression Technique

Short-form versions of the Screening Test of Spanish Grammar (Toronto, 1973) and the Northwestern Syntax Screening Test (Lee, 1971) were devised for use with bilingual Latino children while preserving the original normative data. Application of a multiple regression technique to data collected on 60 lower social status Latino children (four years and six months to seven years and one month) from Spanish Harlem and Yonkers, New York, yielded a small but powerful set of predictor items from the Spanish and English tests. Clinicians may make rapid and accurate predictions of STSG or NSST total screening scores from administration of substantially shortened versions of the instruments. Case studies of Latino children from Chicago and Miami serve to cross-validate the procedure outside the New York metropolitan area.

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