In the airline industry, customer satisfaction occurs when passengers’ expectations are met through the airline experience. Considering that airline service quality is the main factor in obtaining new and retaining existing customers, airline companies are applying various approaches to improve the quality of the physical and social servicescapes. It is common to use data analysis techniques for analyzing customer propensity in marketing. However, their application to the airline industry has traditionally focused solely on surveys; hence, there is a lack of attention paid to deep learning techniques based on survey results. This study has two purposes. The first purpose is to find the relationship between various factors influencing customer churn risk and satisfaction by analyzing the airline customer data. For this, we applied deep learning techniques to the survey data collected from the users who have used mostly Korean airplanes. To the best of our knowledge, this is the one of the few attempts at applying deep learning to analyze airline customer propensities. The second purpose is to analyze the influence of the social servicescape, including the viewpoints of the cabin crew and passengers using aircraft, on airline customer propensities. The experimental results demonstrated that the proposed method of considering human services increased the accuracy of predictive models by up to 10% and 9% in predicting customer churn risk and satisfaction, respectively.

Playing the piano in the correct position is important because the correct position helps to produce good sound and prevents injuries. Many studies have been conducted in the field of piano playing posture recognition that combines various techniques. Most of these techniques are based on analyzing visual information. However, in the piano education field, it is essential to utilize audio information in addition to visual information due to the deep relationship between posture and sound. In this paper, we propose an audio-visual tensor fusion network (simply, AV-TFN) for piano performance posture classification. Unlike existing studies that used only visual information, the proposed method uses audio information to improve the accuracy in classifying the postures of professional and amateur pianists. For this, we first introduce a dataset called C3Pap (Classic piano performance postures of amateur and professionals) that contains actual piano performance videos in diverse environments. Furthermore, we propose a data structure that represents audio-visual information. The proposed data structure represents audio information on the color scale and visual information on the black and white scale for representing relativeness between them. We call this data structure an audio-visual tensor. Finally, we compare the performance of the proposed method with state-of-the-art approaches: VN (Visual Network), AN (Audio Network), AVN (Audio-Visual Network) with concatenation and attention techniques. The experiment results demonstrate that AV-TFN outperforms existing studies and, thus, can be effectively used in the classification of piano playing postures.

Collaborative filtering (CF) is a recommendation technique that analyzes the behavior of various users and recommends the items preferred by users with similar preferences. However, CF methods suffer from poor recommendation accuracy when the user preference data used in the recommendation process is sparse. Data imputation can alleviate the data sparsity problem by substituting a virtual part of the missing user preferences. In this paper, we propose a k-recursive reliability-based imputation (k-RRI) that first selects data with high reliability and then recursively imputes data with additional selection while gradually lowering the reliability criterion. We also propose a new similarity measure that weights common interests and indifferences between users and items. The proposed method can overcome disregarding the importance of missing data and resolve the problem of poor data imputation of existing methods. The experimental results demonstrate that the proposed approach significantly improves recommendation accuracy compared to those resulting from the state-of-the-art methods while demanding less computational complexity.

Cloud computing, which is distributed, stored and managed, is drawing attention as data generation and storage volumes increase. In addition, research on green computing, which increases energy efficiency, is also widely studied. An index is constructed to retrieve huge dataset efficiently, and the layer-based indexing methods are widely used for efficient query processing. These methods construct a list of layers, so that only one layer is required for information retrieval instead of the entire dataset. The existing layer-based methods construct the layers using a convex hull algorithm. However, the execution time of this method is very high, especially in large, high-dimensional datasets. Furthermore, if the total number of layers increases, the query processing time also increases, resulting in efficient, but slow, query processing. In this paper, we propose an unbalanced-hierarchical layer method, which hierarchically divides the dimensions of input data to increase the total number of layers and reduce the index building time. We demonstrate that the proposed procedure significantly increases the total number of layers and reduces the index building time, compared to existing methods through the various experiments.