bluuebunny/crossref_metadata_2025_split huggingface dataset:
Indian and Chinese aviation industry: the EASA framework option
Authors: Kourousis Kyriakos I. , Comer Anthony 
Published: January 2018

Purpose
This viewpoint aims to increase the awareness on the demand faced by the technical sector of the Indian and Chinese aviation industry and how this can be met by the adoption of the European Aviation Safety Agency (EASA) regulatory framework.

Design/methodology/approach
A brief overview of the challenges that the Indian and the Chinese aviation industry is facing is provided, in terms of meeting the demand for sustainable growth. A description of the structure of the EASA framework and its main characteristics is presented, along with a focussed discussion on the framework’s applicability to the Indian and the Chinese aviation maintenance and broader continuing airworthiness sector.

Findings
The EASA regulatory framework can offer a safe and business-effective solution for the Indian and the Chinese aviation industry, aligning with world’s best practice.

Practical implications
A discussion in adopting the EASA framework in India and China can be helpful in increasing awareness and assisting decision makers realise that this is a possible option.

Originality/value
This viewpoint can be useful in provoking discussion, by summarising the key issues and points surrounding aviation regulation standardisation in India and China, along the lines of the EASA framework. Moreover, some possible ways to increase awareness around EASA in India and China are discussed from the point of view of influencing tomorrow’s decision makers.
Evaluation of ozone risk under different air-supply mode in aircraft cabins
Authors: Shi Zhibo , Han Yong , Bai Jie 
Published: January 2018

PurposeThe purpose of this paper is to evaluate the ozone risk introduced by the mixing air-supply mode, displacement air-supply mode and personalized air-supply mode, respectively, in commercial aircraft cabins.Design/methodology/approachIn this study, a computational fluid dynamics (CFD) model of aircraft cabin has been built to study the distribution of ozone mass fraction and the ozone surface deposition rate on passenger’s face and clothes under the three different air-supply modes, respectively. The distribution of ozone mass fraction has been obtained by calculating the mass concentration of ozone in different location. The ozone surface deposition rate on passenger’s face and clothes has been calculated according to the mechanism of the reactions between ozone and squalene, which is the primary reactant in human sebum.FindingsBy comparing the three air-supply modes, it was considered that the mixing air-supply mode made lower ozone concentration and ozone surface deposition risk in most area, but this was because of the thin air distribution in cabin. The displacement air-supply mode made an uneven distribution of ozone concentration and increased absorbing ozone risk in the breathing zone. The personalized air-supply mode was proper for avoiding ozone harm and making a comfortable air environment. The air supply from the inlet on seat back could not increase the ozone surface deposition risk on passenger’s face.Originality/valueThis paper provides the qualitative and quantitative analysis for ozone risk to the passengers under the different air-supply modes. Findings can provide some suggestions for the designers to optimize the air-supply mode of air distribution system for reducing passengers’ discomfort caused by high-altitude ozone introduction, such as breathing in too much ozone.
Nonlinear analysis of VCO jitter generation using Volterra series
Authors: Dehbovid Hadi , Adarang Habib , Tavakoli Mohammad Bagher 
Published: January 2018

PurposeCharge pump phase locked loops (CPPLLs) are nonlinear systems as a result of the nonlinear behavior of voltage-controlled oscillators (VCO). This paper aims to specify jitter generation of voltage controlled oscillator phase noise in CPPLLs, by considering approximated practical model for VCO.

Design/methodology/approachCPPLL, in practice, shows nonlinear behavior, and usually in LC-VCOs, it follows second-degree polynomial function behavior. Therefore, the nonlinear differential equation of the system is obtained which shows the CPPLLs are a nonlinear system with memory, and that Volterra series expansion is useful for such systems.

FindingsIn this paper, by considering approximated practical model for VCO, jitter generation of voltage controlled oscillator phase noise in CPPLLs is specified. Behavioral simulation is used to validate the analytical results. The results show a suitable agreement between analytical equations and simulation results.

Originality/valueThe proposed method in this paper has two advantages over the conventional design and analysis methods. First, in contrast to an ideal CPPLL, in which the characteristic of the VCO’s output frequency based on the control voltage is linear, in the present paper, a nonlinear behavior was considered for this characteristic in accordance with the real situations. Besides, regarding the simulations in this paper, a behavior similar to the second-degree polynomial was considered, which caused the dependence of the produced jitter’s characteristic corner frequency on the jitter’s amplitude. Second, some new nonlinear differential equations were proposed for the system, which ensured the calculation of the produced jitter of the VCO phase noise in CPPLLs. The presented method is general enough to be used for designing the CPPLL.
Taylor series expansion for evaluating the bounds of electric potentials in an electrostatic system with interval parameters
Authors: Wang Pengbo , Wang Jingxuan 
Published: January 2018

PurposeUncertainty is ubiquitous in practical engineering and scientific research. The uncertainties in parameters can be treated as interval numbers. The prediction of upper and lower bounds of the response of a system including uncertain parameters is of immense significance in uncertainty analysis. This paper aims to evaluate the upper and lower bounds of electric potentials in an electrostatic system efficiently with interval parameters.

Design/methodology/approachThe Taylor series expansion is proposed for evaluating the upper and lower bounds of electric potentials in an electrostatic system with interval parameters. The uncertain parameters of the electrostatic system are represented by interval notations. By performing Taylor series expansion on the electric potentials obtained using the equilibrium governing equation and by using the properties of interval mathematics, the upper and lower bounds of the electric potentials of an electrostatic system can be calculated.

FindingsTo evaluate the accuracy and efficiency of the proposed method, the upper and lower bounds of the electric potentials and the computation time of the proposed method are compared with those obtained using the Monte Carlo simulation, which is referred to as a reference solution. Numerical examples illustrate that the bounds of electric potentials of this method are consistent with those obtained using the Monte Carlo simulation. Moreover, the proposed method is significantly more time-saving.

Originality/valueThis paper provides a rapid computational method to estimate the upper and lower bounds of electric potentials in electrostatics analysis with interval parameters. The precision of the proposed method is acceptable for engineering applications, and the computation time of the proposed method is significantly less than that of the Monte Carlo simulation, which is the most widely used method related to uncertainties. The Monte Carlo simulation requires a large number of samplings, and this leads to significant runtime consumption.
Application of the corrected response surface methodology for the optimization of a permanent magnet synchronous machine
Authors: Vivier Stéphane 
Published: January 2018

PurposeThis paper aims to introduce an original application of the corrected response surface method (CRSM) in the context of the optimal design of a permanent magnet synchronous machine used as an integrated starter generator. This method makes it possible to carry out this design in a very efficient manner, in comparison with conventional optimization approaches.

Design/methodology/approachThe search for optimal conditions is achieved by the joint use of two multi-physics models of the machine to be optimized. The former models most finely the physical functioning of the machine; it is called “fine model”. The second model describes the same physical phenomena as the fine model but must be much quicker to evaluate. Thus, to minimize its evaluation time, it is necessary to simplify it considerably. It is called “coarse model”. The lightness of the coarse model allows it to be used intensively by conventional optimization algorithms. On the other hand, the fine reference model makes it possible to recalibrate the results obtained from the coarse model at any instant, and mainly at the end of each classical optimization. The difference in definition between fine and coarse models implies that these two models do not give the same output values for the same input configuration. The approach described in this study proposes to correct the values of the coarse model outputs by constructing an adjustment (correcting) response surface. This gives the name to this method. It then becomes possible to have the entire load of the optimization carried over to the coarse model adjusted by the addition of this correction response surface.

FindingsThe application of this method shows satisfactory results, in particular in comparison with those obtained with a traditional optimization approach based on a single (fine) model. It thus appears that the approach by CRSM makes it possible to converge much more quickly toward the optimal configurations. Also, the use of response surfaces for optimization makes it possible to capitalize the modeling data, thus making it possible to reuse them, if necessary, for subsequent optimal design studies. Numerous tests show that this approach is relatively robust to the variations of many important functioning parameters.

Originality/valueThe CRSM technique is an indirect multi-model optimization method. This paper presents the application of this relatively undeveloped optimization approach, combining the features and benefits of (Indirect) efficient global optimization techniques and (multi-model) space mapping methods.
Solving the electrical impedance tomography inverse problem for logarithmic conductivity
Authors: Pellegrini Sergio P. , Trigo Flavio C. , Lima Raul G. 
Published: January 2018

PurposeIn the context of electrical impedance tomography (EIT), this paper aims to evaluate limitations of estimating conductivity or resistivity, as well as the improvements achieved with the use of an alternate description of the solution space, the logarithmic conductivity.

Design/methodology/approachA quantitative analysis is performed, solving the inverse EIT problem by using the Gauss–Newton and non-linear conjugate gradient methods for a numerical phantom of 15 elements. A property of symmetry is studied for the direct EIT problem for a phantom of 385,601 elements.

FindingsSolving the inverse EIT problem in logarithmic conductivity is more robust to the initial guess, as solutions are kept within physical bounds (conductivity positiveness). Also, convergence is faster and less dependent on the final values of the estimates.

Research limitations/implicationsLogarithmic conductivity provides an advantageous description of the solution space for the EIT inverse problem. Similar estimation problems might be subject to analogous conclusions.

Originality/valueThis study provides a novel analysis, quantitatively comparing the effect of different variables to solve the inverse EIT problem.
Pareto-based branch and bound algorithm for multiobjective optimization of a safety transformer
Authors: Brisset Stéphane , Tran Tuan-Vu 
Published: January 2018

PurposeThis paper aims to propose a multiobjective branch and bound (MOBB) algorithm with a new criteria for the branching and discarding of nodes based on Pareto dominance and contribution metric.

Design/methodology/approachA multiobjective branch and bound (MOBB) method is presented and applied to the bi-objective combinatorial optimization of a safety transformer. A comparison with exhaustive enumeration and non-dominated sorting genetic algorithm (NSGA2) confirms the solutions.

FindingsIt appears that MOBB and NSGA2 are both sensitive to their control parameters. The parameters for the MOBB algorithm are the number of starting points and the number of solutions on the relaxed Pareto front. The parameters of NSGA2 are the population size and the number of generations.

Originality/valueThe comparison with exhaustive enumeration confirms that the proposed algorithm is able to find the complete set of non-dominated solutions in about 235 times fewer evaluations. As this last method is exact, its confidence level is higher.
Use of SQP optimization algorithm to size a multiphysical system
Authors: Tran Le Nhat Hoang , Gerbaud Laurent , Retière Nicolas , Nguyen Huu Hieu 
Published: January 2018

PurposeStatic converters generate current harmonics in power grids. For numerous studies, analytical frequency modeling is preferred to carry out their harmonic modeling in the context of sizing by optimization. However, a design by optimization has to consider other constraints, e.g. modeling constraints and operating constraints. In this way, this paper aims to focus on applying an analytical frequency modeling on the sizing by optimization of an aircraft electrical power channel.

Design/methodology/approachThe paper aims to size a multiphysical system by optimization. In this way, the sizing of an aircraft electrical power channel by optimization has been carried out. The models of all the channel components are analytical. Specifically, the frequency model of the power electronics is based on Tran et al. (2016) and is made of equalities and inequalities. Due to this modeling choice, the optimization satisfies hundreds of constraints, such as modeling constraints and static converter operating constraints. Furthermore, transient constraints are only verified after optimization.

FindingsThe difficulty is the modeling of the system by taking into account nonlinear implicit equations having several solutions. A solution is the addition of inequality constraints to the model to guide the implicit solving. Furthermore, this greatly helps the optimization algorithm to find the good operating mode of the static converter, at steady state. This aspect is indispensable to validate the sizing model.

Research limitations/implicationsThe number of the configurations per operating period of the static converters is defined a priori and limited.

Originality/valueThe analytical model for the sizing is formulated as a constrained optimization problem. Its solving and the sizing by optimization are carried out by the same optimization algorithm.
Design by optimization of controlled static converters with EMC filters in aeronautics
Authors: Baraston Arnaud , Gerbaud Laurent , Schanen Jean-Luc 
Published: January 2018

PurposeWith the increasing number of onboard controlled static converters in aeronautics, methods to design lighter configurations are required. This study aims to help the designer sizing optimal electromagnetic compatibility (EMC) filters and, moreover, finding optimal voltage levels and switching frequency, which have a great impact on the design and global mass of such converters.

Design/methodology/approachAnalytical models for capacitors, inductors and heatsink are settled. Using frequency modeling, EMC can be studied analytically. To deal with frequency and voltages variations, models of perturbations sources are developed. Concerning the problem of surveilling thousands of harmonics to check the whole frequency range of EMC standards in optimization, a strategy that drastically reduces the number of computations and has a good convergence is proposed.

FindingsThe methods settled in the paper allow to optimize a controlled static converter with its EMC filters along with finding optimal switching frequency and voltage levels. A study on a three-phase rectifier reveals the importance of the switching frequency on converter design with EMC filters. A 28 per cent mass reduction is predicted by increasing the switching frequency from 10 to 30 kHz. The designed converters are verified by simulations.

Research limitations/implicationsInvestigating the voltage levels along with the switching frequency has not been achieved yet for static controlled converters with EMC constraints. The approach lacks experimental validations, but it is currently ongoing.

Originality/valueDealing analytically with the changes of frequency or voltages in an EMC study is a new feature. The possibility to use deterministic algorithm is essential for dealing with the important number of constraints and the numerous interactions between all the parts of the problem, especially EMC.
Improvement of topology optimization method based on level set function in magnetic field problem
Authors: Okamoto Yoshifumi , Masuda Hiroshi , Kanda Yutaro , Hoshino Reona , Wakao Shinji 
Published: January 2018

PurposeThe purpose of this paper is the improvement of topology optimization. The scope of the paper is focused on the speedup of optimization.

Design/methodology/approachTo achieve the speedup, the method of moving asymptotes (MMA) with constrained condition of level set function is applied instead of solving the Hamilton–Jacobi equation.

FindingsThe acceleration of convergence of objective function is drastically improved by the implementation of MMA.

Originality/valueNormally, the level set method is solved through the Hamilton–Jacobi equation. However, the possibility of introducing mathematical programming is clear by the constrained condition. Furthermore, the proposed method is suitable for efficiently solving the topology optimization problem in the magnetic field system.
A case-based reasoning approach to rate microcredit borrower risk in online Kiva P2P lending model
Authors: Uddin Mohammed Jamal , Vizzari Giuseppe , Bandini Stefania , Imam Mahmood Osman 
Published: January 2018

PurposeThe purpose of this paper is to discuss the case-based reasoning (CBR) approach to improve microcredit initiatives by means of providing a borrower risk rating system.Design/methodology/approachThe CBR approach has been used to consider the Kiva microcredit system, which provides a characterization (rating) of the risk associated with the field partner supporting the loan, but not of the specific borrower which would benefit from it. The authors discuss how the combination of available historical data on loans and their outcomes (structured as a case base) and available knowledge on how to evaluate the risk associated with a loan request can be used to provide the end users with an indication of the risk rating associated with a loan request based on similar past situations.FindingsThe adopted approach is applied and evaluated employing a selection of cases from individual loans. From this perspective, the case base and the codified knowledge about how to evaluate risks associated with a loan represent two examples of knowledge IT artifacts.Originality/valueThe originality of the work lies in borrower risk rating in online indirect peer-to-peer microcredit lending platforms. The case base and the codified knowledge are the two contributions in knowledge IT artifacts.
Strategizing sustainability in e-commerce channels for additive manufacturing using value-focused thinking and fuzzy cognitive maps
Authors: Shukla Shekhar , Mohanty B.K. , Kumar Ashwani 
Published: January 2018

PurposeThe purpose of this paper is to highlight an innovative approach to explore and evaluate the sustainability perspectives in e-commerce channels for additive manufacturing (AM). This approach helps the stakeholders to perform strategic planning dependent on a scenario-based analysis.Design/methodology/approachThe paper structures the problem of understanding the sustainability perspectives of e-commerce channels for AM using value-focused thinking to identify the related fundamental objectives. These objectives assist in creating dynamic scenarios based on fuzzy cognitive maps of different e-commerce channels for AM.FindingsTo evaluate the proposed research methodology, four scenarios were developed for each e-commerce channel for AM. The exploration and evaluation of one of these scenarios assisted in explaining the whereabouts of the process to aid in strategizing decision situations and understanding these channels better from the sustainability perspective.Practical implicationsThe approach presented in this paper can be used by the practitioners to perform strategic planning for prioritizing sustainability in e-commerce channels for AM; considering the consequences and trade-offs wrt the other factors. Moreover, the scenario-based analysis can be performed depending on the problem requirements of the stakeholder.Originality/valueThe paper addresses the gap of understanding the theoretical aspect of the sustainability perspective in e-commerce channels for AM and the practical aspect of exploring and evaluating them. A scenario-based analysis for each e-commerce channel based on the fundamental objectives of sustainability provides insights for implementation and directions for future research.
Persistent anchoring to default rates when electing 401(k) contributions
Authors: Foltice Bryan , Arling Priscilla A. , Kirby Jill E. , Saajasto Kegan 
Published: January 2018

Purpose
The purpose of this paper is to investigate how the 401(k) auto-enrollment rate influences the size of elected contribution rates in defined contribution plans for new, young enrollees.

Design/methodology/approach
The authors survey 324 undergraduate students at a mid-sized Midwestern university, and compare the elected contribution rates for two groups who were randomly given two default rates: 3 and 15 percent.

Findings
The results indicate widespread evidence of the anchoring and adjusting heuristic in regards to the provided auto-enrollment rate, as the 3 percent default rate group selects a contribution rate of approximately 2 percent less than the group that was provided with the 15 percent default rate. The results also provide support to the benefits of financial education: those who were taking or had already taken a college-level finance course provide higher contribution rates by about 1.7 percent overall. Additionally, individuals with the lowest critical thinking skills elect approximately 2 percent less in annual contributions overall than those who demonstrate higher critical thinking skills.

Originality/value
Interestingly, all groups seem to be susceptible to the anchoring and adjustment heuristic, as the default rate plays a significant role in the elected contribution rate, regardless of an individual’s financial sophistication or critical thinking skill level. The authors hope that these findings prompt benefit plan administrators and policy-makers to reconsider default rates in their retirement plans that would allow for maximum savings and participation rates. The findings also speak in favor of developing programs that would assist enrollees with financial education and critical thinking skills that would yield better retirement savings decisions when asked to make their employee benefit selections.