Affordable Uncertainty Quantification for Industrial Problems: Application to Aero-Engine Fans

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar

Uncertainty quantification (UQ) is an increasingly important area of research. As components and systems become more efficient and optimized, the impact of uncertain parameters is likely to become critical. It is fundamental to consider the impact of these uncertainties as early as possible during the design process, with the aim of producing more robust designs (less sensitive to the presence of uncertainties). The cost of UQ with high-fidelity simulations becomes therefore of fundamental importance. This work makes use of least-squares approximations in the context of appropriately selected polynomial chaos (PC) bases. An efficient technique based on QR column pivoting has been employed to reduce the number of evaluations required to construct the approximation, demonstrating the superiority of the method with respect to full-tensor quadrature (FTQ) and sparse-grid quadrature (SGQ). Orthonormal polynomials used for the PC expansion are calculated numerically based on the given uncertainty distribution, making the approach optimal for any type of input uncertainty. The approach is used to quantify the variability in the performance of two large bypass-ratio jet engine fans in the presence of shape uncertainty due to possible manufacturing processes. The impacts of shape uncertainty on the two geometries are compared, and sensitivities to the location of the blade shape variability are extracted. The mechanisms at the origin of the change in performance are analyzed in detail, as well as the differences between the two configurations.

Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar

Uncertainty Quantification (UQ) is an increasingly important area of research. As components and systems become more efficient and optimized, the impact of uncertain parameters (such as boundary and operating conditions, geometrical variations due to manufacturing or in-service deterioration, etc.) is likely to become critical. It is therefore fundamental to consider the impact of these uncertainties as early as possible during the design process, with the aim of producing more robust designs (less sensitive to the presence of uncertainties). The cost of UQ with high-fidelity simulations becomes therefore of fundamental importance. The companion part I paper presented an efficient approach for UQ based on Polynomial Chaos expansions, demonstrating its applicability to multi-fimensional uncertainty quantification problems. This paper focuses on the application of this approach to quantify the variability in the performance of two large bypass-ratio jet engine fans in the presence of shape uncertainty due to possible manufacturing processes. The impacts of shape uncertainty on the two geometries are compared, and sensitivities to the location of the blade shape variability are extracted. The mechanisms at the origin of the change in performance are analyzed in detail, as well as the differences between the two configurations. These results provide important information both for controling the manufacturing process, and for designing blades that are less sensitive to the presence of manufacturing uncertainties.


Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar

Non-intrusive Polynomial Chaos (NIPC) methods have become popular for uncertainty quantification, as they have the potential to achieve a significant reduction in computational cost (number of evaluations) with respect to traditional techniques such as the Monte Carlo approach, while allowing the model to be still treated as a black box. This work makes use of Least Squares Approximations (LSA) in the context of appropriately selected PC bases. An efficient technique based on QR column pivoting has been employed to reduce the number of evaluations required to construct the approximation, demonstrating the superiority of the method with respect to sparse grid quadratures and to LSA with randomly selected quadrature points. Orthogonal (or orthonormal) polynomials used for the PC expansion are calculated numerically based on the given uncertainty distribution, making the approach optimal for any type of input uncertainty. The benefits of the proposed techniques are verified on a number of analytical test functions of increasing complexity and on two engineering test problem (uncertainty quantification of the deflection of a 3- and a 10-bar structure with up to 15 uncertain parameters). The results demonstrate how an LSA approach within a PC framework can be an effective method for UQ, with a significant reduction in computational cost with respect to full tensor and sparse grid quadratures.


2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.


2014 ◽  
Vol 1 (2) ◽  
pp. 187
Author(s):  
Serdar KUZU

The size of international trade continues to extend rapidly from day to day as a result of the globalization process. This situation causes an increase in the economic activities of businesses in the trading area. One of the main objectives of the cost system applied in businesses is to be able to monitor the competitors and the changes that can be occured as a result of the developments in the sector. Thus, making cost accounting that is proper according to IAS / IFRS and tax legislation has become one of the strategic targets of the companies in most countries. In this respect, businesses should form their cost and pricing systems according to new regulations. Transfer pricing practice is usefull in setting the most proper price for goods that are subject to the transaction, in evaluating the performance of the responsibility centers of business, and in determining if the inter-departmental pricing system is consistent with targets of the business. The taxing powers of different countries and also the taxing powers of different institutions in a country did not overlap. Because of this reason, bringing new regulations to the tax system has become essential. The transfer pricing practice that has been incorporated into the Turkish Tax System is one of the these regulations. The transfer pricing practice which includes national and international transactions has been included in the Corporate Tax Law and Income Tax Law. The aim of this study is to analyse the impact of goods and services transfer that will occur between departments of businesses on the responsibility center and business performance, and also the impact of transfer pricing practice on the business performance on the basis of tax-related matters. As a result of the study, it can be said that transfer pricing practice has an impact on business performance in terms of both price and tax-related matters.


Author(s):  
Alizaman D. Gamon ◽  
Mariam Saidona Tagoranao

This study discusses the penetration of Islam in the Philippines, particularly the third wave of its expansion, which was brought by Sufi missionaries. It reinstates the historical relevance of Sufi ideas and approaches due to its contemporary relevance to the concept of social co-existence. The rational, intellectual and philosophical dimension of Islam is manifested in the cultural and traditional life of Muslim communities. The study also analyzes the impact of Muslim struggle for the development of Islamic institutions in the context of the secular state. The ongoing, unsettled debate between Islamic and government approaches to peace and development in Mindanao and Sulu continues unabated. Over the years, reforms were introduced, but in their midst, evidence of government biases and prejudices with regards to Islamic institutions have surfaced. Muslim leaders and intellectuals responded in the context of historical rights and freedom, but those views were often questioned as they are presumed to be incompatible with the national agenda for national unity. It was very recently that this incompatibility was readdressed giving support to having lasting peace and justice in Mindanao. The study argues that there have been substantial state-sponsored reforms which may contribute to the gradual advancement of Muslim communities. Though the path for the passage of Muslim concerns within the given condition is fragile and open to challenges, the study recognizes the prominence of inter-civilizational dialogue, from which the universal values of humanity will be embraced by both Muslim and non-Muslim policy makers. In addition, Muslim and non-Muslim communities in the Philippines need to embrace the universal principle of humanity and coexistence due to its relevance to the political stability and economic growth in the country.  Keywords: Muslims in the Philippines, Islamic institutions, Islamization, Muslim intellectuals, Reform. Abstrak Kajian ini mengkaji tentang kemasukan Islam, terutamanya gelombang ketiga perkembangannya, yang dibawa oleh para pendakwah sufi. Kajian itu mengembalikan semula sejarah penting tentang idea-idea dan pendekatan Sufi yang boleh digunapakai pada masa kini untuk mewujudkan keharmonian sosial di kalangan rakyat pelbagai agama. Pemahaman tentang Islam mempunyai pengaruh yang jelas terhadap kebudayaan dan tradisi Islam. Kajian ini juga menganalisis kesan perjuangan Muslim untuk pembangunan institusi Islam dalam konteks sebuah negara sekular. Perbahasan yang berterusan yang tidak menemukan penyelesaian antara pendekatan Islam dan pendekatan kerajaan untuk perdamaian serta pembangunan di Mindanao dan Sulu terus berlanjutan. Walaupun  bertahun-tahun pembaharuan telah dilakukan, namun terdapat bukti penolakan dan prasangka buruk kerajaan terhadap institusi Islam. Para pemimpin dan intelektual Muslim bertindak berdasarkan pada fakta sejarah dan hak kebebasan bersuara, namun pandangan mereka sering dipertikaikan kerana mereka dianggap tidak seiring dengan agenda dan perpaduan nasional. Baru-baru ini ketidakserasian ini mulai disuarakan semula untuk mendapat sokongan terhadap keamanan dan keadilan yang berterusan di Mindanao. Kajian ini mendapati bahawa terdapat pembaharuan yang dilakukan oleh pihak kerajaan yang boleh menyumbang ke arah  kemajuan masyarakat Islam secara beransur-ansur. Walaupun pendekatan bagi memenuhi hasrat orang Islam masih dalam keadaan yang rapuh dan penuh cabaran, namun kajian ini mengusulkan peripentingnya dialog antara peradaban dimana nilai-nilai universal manusia akan diperoleh dan dipegang oleh kedua-kedua pihak pembuat dasar iaitu  Islam dan bukan Islam. Di samping itu, umat Islam dan bukan Islam di Filipina perlu mengkaji dan mencontohi model keharmonian sosial Malaysia dan Singapura kerana kaitannya dengan kestabilan politik dan pertumbuhan ekonomi. Kata Kunci: Muslim di Filipina, institusi Islam, Islamisasi, intelektual Islam, Pembaharuan.


2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product


2010 ◽  
Vol 4 (3) ◽  
pp. 32-36 ◽  
Author(s):  
Deborah Schofield ◽  
Rupendra Shrestha ◽  
Emily Callander ◽  
Richard Pervical ◽  
Simon Kelly ◽  
...  

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