scholarly journals Predicting CO2Minimum Miscibility Pressure (MMP) Using Alternating Conditional Expectation (ACE) Algorithm

Author(s):  
O. Alomair ◽  
A. Malallah ◽  
A. Elsharkawy ◽  
M. Iqbal
Author(s):  
Jörg Aßmus ◽  
Niels Wessel ◽  
Jürgen Kurths ◽  
Frank Weidermann ◽  
Jan Konvicka ◽  
...  

Abstract Precision and productivity are very important criteria for the evaluation of modular tool systems and require a thermally stable process with tolerances in the micrometer range. During the past decades there has been an increasing interest in compensating thermally induced errors. In this paper we investigate wheather a prediction of thermal displacement based on a nonlinear regression analysis is possible, namely using the alternating conditional expectation algorithm (ACE) introduced by Breiman and Friedman, 1985. The data we are analyzing were generated by two different finite element spindle models of modular tool systems. As the main result we find that the ACE-algorithm is a powerful tool to model the relation between temperatures and displacements. It could also be a promising approach to handle well-known hysteresis effects. Limitations of this study are the model restricted results, next our findings have to be validated on real data.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaoqin Li ◽  
Xiao Yang ◽  
Zude Ding ◽  
Xi Du ◽  
Jincheng Wen

Engineered cementitious composites (ECC) have higher ultimate tensile strains than normal concrete. The mechanical properties of ECC strongly depend on raw materials and the mix proportions. The uniform design test method and alternating conditional expectation, which is a nonparametric regression analysis method, were used to design the ECC mix proportion. According to the regression analysis, the optimized W/B, S/B, and F/B ranges could be obtained as 0.35–0.42, 0.25–0.3, and 0.02, respectively. The tested proportions for validation were randomly adopted within the range of W/B, S/B, and F/B. The uniaxial compression, tension, and four-point bending tests were conducted to verify the material behaviour of the designed ECC. Results showed that all the specimens had large ultimate tensile strains and high fracture energy capacities, and strain hardening was also observed. The fibers were found to be uniformly distributed in the specimens by using a scanning electron microscope. This paper may provide theoretical and practical guidance for the ECC and other cement-based material mix proportion design.


2019 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Joyce Low ◽  
Kum Khiong Yang

Purpose: This study investigates the relationships between service efficiency in 5 major cost centres (namely, business orientation, network coverage, physical resources, maintenance, repair and overhaul (MRO), and human resources) and profitability in the global airline industry.Design/methodology/approach: The study integrates the Slack-based Model (SBM) of Data Envelopment Analysis (DEA) with the Alternating Conditional Expectation (ACE) regression to understand the relationships between an airline’s profitability and its efficiencies in 5 identified operations areas.Findings: Based on the observational data obtained from 75 international airlines, the relationships between operational performances and profitability are found to be curvilinear and contingent on an airline’s operating model.Research limitations/implications: The omission of non-IATA airlines and many low cost carriers may hinder a holistic view of the airline industry.Practical implications: Management can influence the profitability of an airline through its strategic operations decisions that affect an airline’s cost, service quality, and financial structure after the influences of location and size have set the stage. Airlines pursuing cost leadership should seek to increase productivity especially in MRO, human resources and physical resources; whereas airlines pursuing service differentiation may choose to provide quality service at lower efficiencies or pursue an approach to improve quality and efficiencies simultaneously.Originality/value: Identifying operations practices that are consistent with a firm’s competitive priorities is important in the multifaceted service environment today. An integrated SBM-ACE regression model, which permits different input-output mix, variable return to scale and non-linear relationship, is proposed and applied to analyze the profit impact of service efficiencies in the five key operations areas.


PETRO ◽  
2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Reza Dwi Adrianto

<p>Batuan karbonat merupakan salah satu batuan yang sangat bagus sebagai batuan reservoar, namun batuan ini memiliki tingkat heterogenitas yang sangat tinggi dibandingkan dengan batupasir sehingga memerlukan pendekatan dengan melakukan <em>rock typing. </em>Pada umumnya, indentifikasi <em>rock type </em>membutuhkan hasil pengukuran dari <em>core </em>dengan menggunakan beberapa metode yang telah ada. Namun, pada sumur-sumur yang tidak memiliki data <em>core </em>sangat sulit untuk menerapkan metode tersebut. Penelitian ini dilakukan dalam upaya untuk menentukan <em>Hydraulic Flow Unit </em>(HFU) reservoar pada sumur yang memiliki data <em>core </em>dengan menggunakan parameter <em>Flow Zone Indicator </em>(FZI) dan metode regresi non-parametrik yang disebut <em>Alternating Conditional Expectation </em>(ACE) pada sumur yang tidak memiliki data <em>core</em>. Dari hasil penelitian, reservoar pada lapangan RN dapat dikelompokkan menjadi delapan flow unit. Delapan flow unit tersebut masing-masing memiliki permeabilitas sebagai fungsi dari porositas yang telah divalidasi dengan mengaplikasikannya pada sumur. Dengan menggunakan metode ACE, kita dapat menentukan <em>Hydraulic Flow Unit </em>pada sumur yang tidak memiliki data <em>core </em>dengan menggunakan data log. Setelah FZI dihitung dari data <em>log </em>dan divalidasi dengan data <em>core </em>terlihat bahwa hasil dari metode tersebut menghasilkan korelasi yang cukup baik (R<sup>2</sup> = 0.84), sehingga metode tersebut cukup dapat diaplikasikan pada sumur-sumur yang tidak memiliki data <em>core</em>.</p>


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