This study aims to analyze user reviews of the Chinese flea market app Xianyu through text mining to identify the characteristics of consumer purchasing behavior and user experience. Review data were collected from the App Store using Python, and keyword frequency analysis, co-occurrence network analysis, correspondence analysis, and cross-tabulation were conducted with KH Coder. The results reveal that users' satisfaction is influenced by factors such as usability, product quality, and convenience, while dissatisfaction stems from issues like fraud, poor customer service, and account suspensions. A polarization of user experiences was observed, with a high concentration of both 1-star and 5-star ratings. This study provides insights into user perceptions on C2C platforms and offers practical implications for improving platform operations.

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It is important to maintain of homeostasis and to keep an electric potential of axon by ionic channels. This activity is performed through various ions, Na+, K+, Cl－ and by their ionic channels, which are expressed as electric potential of difference between inside and outside of cell membranes. The conversion equation, which ranslating from various ions’ concentrations to electric currents and electric potential, corresponds to the famous current equation of Goldman-Hodgkin-Katz (GHK). The GHK is derived from hypothesis of the theory of constant filed. In this paper, we proposed an expanded membrane electric theory, which are generalized GHK and the theory of constant field. And we make an attempt to re-construct to generalized GHK, and show re-emergency and expandable of those famous relations.

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There is a lot of previous research on profit maximization in agriculture. In a previous research, crop rotation problem and cultivation management problem are solved as one integrated management problem in order to maximize the profit of multiple farm fields in agriculture under cost constraints. But in the previous research, it is assumed that crop prices do not fluctuate. In this research, the cost constrained integrated management problem for multiple farm fields considering price fluctuations is studied. A new integrated management method is proposed. The integrated management problem is modeled by Markov decision processes. The proposed method maximizes the expected profit of multiple farm fields considering price fluctuations under cost constraints by dynamic programming. In the numerical calculation results, adaptive crop selection examples and cultivation action selection examples considering price fluctuations are confirmed. This research is basic research, and future extended research is required. For example, as a more realistic problem setting, the integrated management problem with unknown probabilities is interesting.

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There is a lot of previous research on sales promotion strategy using digital signage. Maximization of expected sales is one of important topics on sales promotion strategy using digital signage. In the previous research, only maximization of expected sales for one customer with unknown customer class which indicates changeable purchasing intention has been studied. But maximization for multiple customers has not been studied. In this research, a new sales promotion strategy which maximizes the expected sales for multiple customers based on statistical decision theory is proposed. In the proposed method, the expected sales are maximized with respect to a Bayes criterion. The effectiveness of the proposed method is shown by some computational examples. The expected sales of the proposed method are greater than those of comparison targets. In this research, the expected sales are maximized under the condition that all probabilities are known. But the probabilities are unknown in real cases. An expansion of this research with unknown probabilities is one of further works.

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This study aimed to address "occupational low back pain," a common issue for nurses, by evaluating posture improvement using a portable device and an app that provides posture feedback. The device detects hazardous postures and issues warnings via vibrations or sounds, with results viewable on an Android app. The experiment took place at Koyu Sagamihara Hospital with 1 nurse practitioner, and 7 nursing assistants working day and night shifts while wearing the device. Posture improvements were assessed with and without warnings, and subjects with data showed improvement based on measured parameters.

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