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This paper aims to provide a precision assembly method to improve the aircraft engine quality of initial unbalance with the purpose of founding the process for mass eccentricity propagation and demonstration of assembly process. The proposed method can be used for assembly guidance, tolerance allocation and so on, especially for the assembly with a large number of rotors and the assembly requirements of initial unbalance and coaxiality in high precision.

This paper proposes a constrained optimization-build method to minimize initial unbalance of aircraft engine assembly, which takes amount of unbalance and concentricity of each rotor into account. A constrained nonlinear programming model is extracted by choosing the initial unbalance as the objective function, and choosing the coaxiality and assembly orientations as the nonlinear constraints. The initial unbalance is reduced stage-by-stage by controlling the assembly angle of each rotor.

The validity and accuracy of the proposed method is verified by the multistage rotors assembly through experiments run with the measuring instruments. Compared with the direct-build method, the initial unbalance of final assembly using proposed method is reduced by 22.2% in four rotors assembly.

Different from the geometric eccentricity propagation control methods to reduce the initial unbalance indirectly, this paper establishes mass eccentric propagation model in multistage rotors assembly of aircraft engine for the first time. It provides a new idea to establish the relationship between the amount of unbalance of each rotor and the initial unbalance of multistage rotors.

Aiming at the problem that the transmission mechanism of the assembly error of the multi-stage rotor with saddle surface type is not clear, the purpose of this paper is to propose a deep belief network to realize the prediction of the coaxiality and perpendicularity of the multi-stage rotor.

First, the surface type of the aero-engine rotor is classified. The rotor surface profile sampling data is converted into image structure data, and a rotor surface type classifier based on convolutional neural network is established. Then, for the saddle surface rotor, a prediction model of coaxiality and perpendicularity based on deep belief network is established. To verify the effectiveness of the coaxiality and perpendicularity prediction method proposed in this paper, a multi-stage rotor coaxiality and perpendicularity assembly measurement experiment is carried out.

The results of this paper show that the accuracy rate of face type classification using convolutional neural network is 99%, which meets the requirements of subsequent assembly process. For the 80 sets of test samples, the average errors of the coaxiality and perpendicularity of the deep belief network prediction method are 0.1 and 1.6 µm, respectively.

Therefore, the method proposed in this paper can be used not only for rotor surface classification but also to guide the assembly of aero-engine multi-stage rotors.

The purpose of this paper is to test the conceptual model of consumers’ intention and satisfaction towards mobile wallets. This study uses the integrated UTAUT model which includes variables such as ease of use, trust, security, self-efficacy, etc., and an additional variable (hedonism) to test consumers’ behaviour in the context of mobile banking technologies. Regression analysis, ANOVA and descriptive analysis are used to test the relationship among several dimensions such as perceptions, preferences, satisfaction and usage rate of mobile wallets in North India. A sample of 204 North Indian consumers was taken to understand the consumers’ adoption behaviour towards mobile wallet. The study explains the significance of the proposed model and its effectiveness to understand the behaviour of North Indian consumers. The result shows a significant association between consumers’ perception, preference, usage and satisfaction. Security, trust and hedonism are few of the most influencing variables in the study. Demographic variables such as gender and age also influence consumer satisfaction and usage rate of mobile wallets in North India. The proposed model and results of the study bring valuable insights into researchers and practitioners in the context of usage of mobile wallets.

Various standardized scales were used in the present study. Statistical techniques like descriptive statistics, analysis of variance, t-test, χ² and regression analysis were used to assess the data. The data were collected with three separate questionnaires on variables perception, preference, usage and satisfaction.

Findings of this study show a strong relation between customer’s perception, preference and satisfaction of mobile wallet users. The result also shows the impact of customer’s perception, satisfaction and preference on the usage rate of mobile wallets in India. The authors have collected responses from the various regions in south and North India.

The first contribution of this study is that it shows a strong correlation between consumers’ perception, preferences and satisfaction. Various studies are available to understand the impact of perception on satisfaction (Samudra and Phadtare, 2012; Venkatesh and Davis, 2000, Thakur, 2013), but very few studies have integrated it with preference and mobile wallet usage. Moreover, no study is available on these variables specifically for North Indian consumers. This study is unique in the sense that it discuss the association of consumer’s perception with type of transactions they prefer to do in M-wallets. This paper also identify one more crucial factors, “hedonism” which is not discussed extensively in the literature.

The study has several implications to the mobile technology industry and the banking system to identify new strategies for mobile wallet usage. Factors like security, convenience and trust influence consumers’ intention. This indicates that industries and banks must verify users’ privacy norms and evaluate social trends to enhance user’s satisfaction and usage rate. Hedonism is determined as one of the significant variable to measure consumer’s satisfaction and usage tendency. Mobile technology providers should work on the appearances and design of the apps, and promote its convenience and benefits to increase its usage in North India. Based on the findings of this study, companies can also evaluate preferred wallet services for consumers, and factors affecting those services. This will help them to add more attractive services based on consumers’ feedback, and remove unwanted services.

The study also stressed the impact of society and family/friends on mobile wallet’s usage. Customers learn new things from family and society and get influence with their choice and preferences. This will help institutions to understand various factors leads to mobile wallet usage and enhance the satisfaction level of customers.

Although various studies have been conducted on the perception of customers on various mobile payment systems, but this paper is the first of its kind to study customer’s perception about wallets and type of transactions; they prefer to do through mobile wallets. This paper also study the impact of mobile wallet usage and various factors affecting the usage rate. This paper also identified one crucial factor, “hedonism”, which is not discussed thoroughly in the literature, and its significance in North India.