Browsing by Author "Chang, Chia-Chi"

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A NOVEL INDEX OF PHOTOPLETHYSMOGRAPHY BY USING INSTANTANEOUS PULSE RATE VARIABILITY DURING NON-STATIONARY CONDITION
(2015)
Lin, Pei-Chen
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Huang, Po-Hsun
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Chang, Chia-Chi
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Hsu, Hung-Yi
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Hsiao, Tzu-Chien
Heart rate variability (HRV) and pulse rate variability (PRV) have been widely used as an automatic nervous system (ANS) activities observation. Based on the timescale limitation of heart beat (for HRV) and pulse waveform (for PRV), one method of instantaneous pulse rate variability (iPRV) with photoplethysmography (PPG) had been proposed as a HRV and PRV surrogate during non-stationary condition in frequency domain. In this paper, the examination in time-domain PPG during passive leg raise (PLR) trial was studied. The 24 subjects pre-experiment resulted that iPRV and HRV are positive correlation (r-value = 0.680 +/- 0.099 in baseline; r-value = 0.688 +/- 0.096 in PLR). Furthermore, the iPRV containing much complex intrinsic components on higher frequency bands provides more intrinsic cardiovascular information for further assessment. This proposed examination in time-domain PPG is the possible leading way to more useful indicator for healthcare application.
Alleviating the negative impact of delayed recovery: process- versus outcome-focused explanations
(2013)
Chang, Chia-Chi
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Chen, Chia-Yi
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管理科學系
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Department of Management Science
Purpose - Limited research has explored the potential marketing strategies to counter the damage associated with delayed recovery. Based on the construal level theory, this study seeks to suggest that customers tend to focus on different aspects of the compensation according to the speed of recovery. Thus, providing an adequate explanation to customers corresponding to expected recovery speed can effectively alleviate customer dissatisfaction with a delayed recovery. Design/methodology/approach - This study examined the proposed hypotheses using a 2 (immediate vs delayed) by 2 (explanation: process-focused vs outcome-focused) experimental design. Findings - The analytical results show that when an immediate recovery is available, an outcome-focused explanation will result in higher post-failure satisfaction than will a process-focused explanation. Conversely, when a delayed recovery is expected, post-failure satisfaction is higher for customers who receive a process-focused explanation than for those who receive an outcome-focused explanation. Practical implications - This study thus recommends that firms should provide explanations compatible with expected recovery speed to better enhance post-failure satisfaction. Originality/value - This study contributes to the body of service recovery literature by examining the differential effectiveness of outcome-focused and process-focused explanations under immediate and delayed recovery conditions. The findings provide a guideline that managers can use to formulate suitable explanations to alleviate the detrimental effects of delayed recovery.
An Effective Arterial Blood Pressure Signal Processing System Based on EEMD Method
(2014-01-01)
Chuang, Shang-Yi
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Liao, Jia-Ju
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Chou, Chia-Ching
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Chang, Chia-Chi
;
Fang, Wai-Chi
This study proposed an effective signal processing system based on Ensemble Empirical Mode Decomposition (EEMD) method for the analysis of arterial blood pressure (ABP). The whole system was implemented on an ARM-based SoC development platform to attain the on-line non-stationary signal processing. A non-invasive blood pressure acquisition device (NIBP100D) was used to record the continuous ABP as the input signal. According to the non-stationary characteristics of ABP, EEMD is useful to achieve accurate decomposition for ABP spectral analysis. The signal was decomposed into several Intrinsic Mode Functions (IMFs) by EEMD, and quantitatively assessed by fast Fourier transform (FFT). The results showed that the proposed EEMD processor can effectively solve the mode mixing problem of Empirical Mode Decomposition (EMD) and the FFT spectrum of IMF5, IMF6, and IMF7 to reveal heart rate and respiration.
An Effective Photoplethysmography Signal Processing System Based on EEMD Method
(2015)
Liao, Jia-Ju
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Chuang, Shang-Yi
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Chou, Chia-Ching
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Chang, Chia-Chi
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Fang, Wai-Chi
This study proposed an effective signal processing system based on Ensemble Empirical Mode Decomposition (EEMD) method for the analysis of Photoplethysmography (PPG). The whole system was implemented on an ARM-based SoC development platform to attain the on-line non-stationary signal processing. A non-invasive near-infrared light sensing device was used to record the continuous PPG as the input signal. According to the non-stationary characteristics of PPG, EEMD is useful to achieve accurate analysis for PPG. The signal was decomposed into several Intrinsic Mode Functions (IMFs) by EEMD. The results showed that the proposed EEMD processor can effectively solve the mode mixing problem of Empirical Mode Decomposition (EMD). This study examined its possibility based on specific architecture with an on-board Xilinx FPGA. It was helpful for non-stationary biomedical signal processing and cardiovascular diseases research.
Analysis of critical factors for social games based on extended technology acceptance model: a DEMATEL approach
(2018-01-01)
Chang, Chia-Chi
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Chen, Po-Yu
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交大名義發表
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National Chiao Tung University
In recent years, social games such as Farmville' and Pokemon Go' have become a major game type in the gaming industry. This study examines the importance of different factors in social games using the Technology Acceptance Model (TAM) and DEMATEL. The result shows social norm' as the most important factor overall. It is also found that pleasure' and sociability' are the most important aspects in perceived enjoyment'. Regarding key aspects in each factor, flow experience' is crucial in perceived attractiveness', game fairness' largely influential in social norm', and reputation of platform and service provider' a decisive aspect in platform service and corporate image'. These findings and analyses are apt references for social game providers to improve their services.
Coefficient of Variation of Electrocardiographic R-R Intervals in Healthy Subjects and Stroke Patients
(2012)
Hsu, Hung-Yi
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Chang, Chia-Chi
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Hsiao, Tzu-Chien
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Chiang, Yi-Ying
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資訊工程學系
Countering negative country-of-origin effects The role of evaluation mode
(2010)
Chu, Po-Young
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Chang, Chia-Chi
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Chen, Chia-Yi
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Wang, Tzu-Yun
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管理科學系
Purpose - As multinational firms seek to acquire competitive cost advantages through global sourcing, it is also important for them to develop effective strategies to reduce possible damage of a negative country-of-origin (COO) effect. This study aims to examine whether brand image and evaluation mode could alleviate a negative COO effect. Design/methodology/approach - A 2(COO) x 2(brand) x 2(evaluation mode) experimental design was employed in order to examine whether brand and COO effects on product evaluation vary under different evaluation modes. The data were analyzed by a repeated measure MANOVA. Findings - The results showed that products made in favourable countries were rated higher in joint evaluation mode than in separate evaluation mode. Conversely, products made in unfavourable countries were better evaluated in separate evaluation mode than in joint evaluation mode. The results of the study are not in favour of the notion that a strong brand image could overcome the negative effect of COO. Research limitations/implications - Conclusions of the study suggest that the COO effect plays an equally important role in consumer product evaluation for both strong and weak brands. Thus, even for a product with strong brand image, the negative consequences of COO stemming from consumer unfavourable attitudes towards the manufacturing country are not likely to be completely eliminated. Moreover, to alleviate the negative impact of unfavourable COO, marketers may want to avoid direct comparison between products made in unfavourable countries with those made in favourable countries, regardless of their brand strength. Practical implications - When marketing a product made in an unfavourable country, marketers should manage to create a selling environment facilitating a separate evaluation mode. In contrast, marketers should proactively manage to display products from favourable countries along with those from unfavourable countries in order to further enhance quality perceptions. Originality/value - The results of the study could help marketers employ advantageous merchandizing or advertising strategies to lessen the negative effect of COO.
Education system integration in cross-disciplinary with colleges - Virtual biomedical instrument (VBI) for example
(2008-06-01)
Hsiao, Tzu-Chien
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Chang, Chia-Chi
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Liu, Chien-Sheng
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Lin, Chii-Wann
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Wang, Chih-Yu
Due to the rapid development of computer science, software, and biomedical engineering, many clinical diagnosis instruments and control system improved accordingly. The minimization and practicality of sensors, as well as the efficiency and stability of computers make simulation control system in medical instruments become the most important part of developing items. The relevant subject of course, virtual biomedical instrumentations (VBI), which combined with computer science, electrical engineering, and medical science, has become a major developing course in biomedical education. Cross-disciplinary research needs experts in different areas and most cross-disciplinary schools cannot afford it. So it requires integration and cooperation between schools. To address this issue, a graduated course has been designed to provide an opportunity for all professions in each field to discuss and share their resources on an e-learning platform. With the progress of the project, VBI course integrates biomedical education resources from north to south colleges to reduce the request of manpower for cross-disciplinary course of biomedical. In addition, VBI courses initiate the cooperation between academic community and industry.
Effects of individuals' locus of control and computer self-efficacy on their e-learning acceptance in high-tech companies
(2014-01-02)
Hsia, Jung-Wen
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Chang, Chia-Chi
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Tseng, Ai-Hua
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管理科學系
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Department of Management Science
High-tech companies encounter intense competition in today's global economy. With rapid changes in working environments, high-tech employees must learn quickly and effectively to solve difficult problems and increase their productivity. Many large high-tech companies have recently implemented electronic learning (e-learning) for employee training. However, e-learning systems are expensive and often underutilised. Therefore, understanding the factors associated with acceptance to e-learning are of priority concern. By integrating locus of control, computer self-efficacy and technology acceptance model (TAM) into one model, this study examines the feasibility of the extended TAM to explain employee acceptance of e-learning systems. Data were collected from 223 employees at five high-tech companies located in the Hsinchu Science Park, Taiwan. Analytical results indicate that locus of control had significant direct effects on perceived usefulness and perceived ease of use. Computer self-efficacy had significant direct effects on perceived ease of use and behavioural intention to use. Overall, analytical results provide strong support for using the extended TAM to explain user acceptance of e-learning systems. The research and practical implications of findings are discussed.
Examining Hedonic and Utilitarian Bidding Motivations in Online Auctions: Impacts of Time Pressure and Competition
(2015-12-01)
Chang, Chia-Chi
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Chen, Chi-Wen
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交大名義發表
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National Chiao Tung University
Hedonic and utilitarian bidding motivations have seldom been studied in the context of consumer-to-consumer (C2C) online auctions. Drawing on the stimulus-organism-response (S-O-R) framework, this study establishes a structural equation model to examine how competition and time pressure (stimulus) influence bidders\' hedonic and utilitarian motivations (organism) and how these motivations further affect impulse bidding and satisfaction with the bidding process (responses). Our results show that time pressure is a significant predictor of utilitarian motivation but is not significantly related to hedonic motivation. Moreover, hedonic motivation tends to increase impulse bidding, whereas utilitarian motivation discourages it. Finally, this study finds the relationship between impulse bidding and satisfaction to be significant. Our findings contribute to theory by describing the roles that bidders\' hedonic and utilitarian motivations play in C2C online auctions and elucidating the important implications for practice in attracting individuals to bid in such auctions.
Fluorescence Intrinsic Characterization of Excitation-Emission Matrix Using Multi-Dimensional Ensemble Empirical Mode Decomposition
(2013-11-01)
Chang, Chi-Ying
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Chang, Chia-Chi
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Hsiao, Tzu-Chien
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分子醫學與生物工程研究所
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資訊工程學系
Excitation-emission matrix (EEM) fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds due to overlapping features. Conventional studies use principal component analysis (PCA) for EEM fluorescence analysis, and the relationship between the EEM features extracted by PCA and diseases has been examined. The spectral features of different tissue constituents are not fully separable or clearly defined. Recently, a non-stationary method called multi-dimensional ensemble empirical mode decomposition (MEEMD) was introduced; this method can extract the intrinsic oscillations on multiple spatial scales without loss of information. The aim of this study was to propose a fluorescence spectroscopy system for EEM measurements and to describe a method for extracting the intrinsic characteristics of EEM by MEEMD. The results indicate that, although PCA provides the principal factor for the spectral features associated with chemical compounds, MEEMD can provide additional intrinsic features with more reliable mapping of the chemical compounds. MEEMD has the potential to extract intrinsic fluorescence features and improve the detection of biochemical changes.
Frequency range extension of spectral analysis of pulse rate variability based on Hilbert-Huang transform
(2014-04-01)
Chang, Chia-Chi
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Hsiao, Tzu-Chien
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Hsu, Hung-Yi
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資訊工程學系
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友訊交大聯合研發中心
Heart rate variability (HRV) is a well-accepted indicator for neural regulatory mechanisms in cardiovascular circulation. Its spectrum analysis provides the powerful means of observing the modulation between sympathetic and parasympathetic nervous system. The timescale of HRV is limited by discrete beat-to-beat time intervals; therefore, the exploration region of frequency band of HRV spectrum is relatively narrow. It had been proved that pulse rate variability (PRV) is a surrogate measurement of HRV in most of the circumstances. Moreover, arterial pulse wave contains small oscillations resulting from complex regulation of cardiac pumping function and vascular tone at higher frequency range. This study proposed a novel instantaneous PRV (iPRV) measurement based on Hilbert-Huang transform. Fifteen healthy subjects participated in this study and received continuous blood pressure wave recording in supine and passive head-up tilt. The result showed that the very-high-frequency band (0.4-0.9 Hz) varied during head-up tilt and had strong correlation (r = 0.77) with high-frequency band and medium correlation (r = 0.643) with baroreflex sensitivity. The very-high-frequency band of iPRV helps for the exploration of non-stationary autoregulation and provides the non-stationary spectral evaluation of HRV without distortion or information loss.
I Want Products My Own Way, But Which Way? The Effects of Different Product Categories and Cues on Customer Responses to Web-based Customizations
(2009-02-01)
Chang, Chia-Chi
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Chen, Hui-Yun
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管理科學系
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Department of Management Science
Mass customization is a strategy that has been adopted by companies to tailor their products in order to match customer needs more precisely. Therefore, to fully capture the value of mass customization, it is crucial to explore how customers react to mass customization. In previous studies, an implied premise has been that consumers are keen to embrace customized products, and this assumption has also been treated by firms as a prerequisite for successful mass customization strategies. However, an undesirable complexity may result from difficult configuration processes that may intimidate and confuse some customers. Hence, this study explores strategies that marketers can employ to facilitate the customization process. Specifically, this study investigates how to enhance customer satisfaction and purchase decision toward customized products by providing cues compatible with the product category. It is hypothesized that for search products, customers rely more on intrinsic cues when making configuration decisions. On the other hand, for experience products, customers perceive extrinsic cues to be more valuable in assisting them to make configuration decisions. The results suggest that consumers tend to respond more favorably toward customized search products when intrinsic cues are provided than when extrinsic or irrelevant ones are provided. In contrast, when customizing experience products, customers tend to depend more on extrinsic cues than on intrinsic or irrelevant ones.
Quantitative Non-stationary Assessment of Cardiovascular Diseases based on Arterial Blood Pressure Waveform by using Hilbert-Huang Transform
(2013-01-01)
Chang, Chia-Chi
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Hsu, Hung-Yi
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Hsiao, Tzu-Chien
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資訊工程學系
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Department of Computer Science
Analysis of arterial blood pressure (ABP) signal provides valuable information of cardiovascular function. But ABP\'s non-stationary characteristics are still unclear and it is hard to evaluate non-stationary characteristics by stationary analysis method, such as Fourier transform and wavelet transform. The aim of the study is to quantitatively evaluate the ABP\'s non-stationary characteristics and examine the feasibility of this method by the study of cardiovascular diseases patients. Eight ABP\'s intrinsic features were extracted by empirical mode decomposition (EMD) and were evaluated by averaged period and energy density according to the spectral integration method. In the study, 33 subjects (15 healthy subjects, 7 patients with autonomic failure, 11 patients with orthostatic tachycardia syndrome) participated in the passive head-up tilt experiment. The results showed that the characteristics of ABP fluctuation were clearly presented by the changes of IMFs and corresponding averaged periods and energy density. This method was feasible for the qualitative and quantitative assessment of ABP in normal healthy subjects and patients with impaired autonomic regulation of cardiovascular system.
Reflection Wave Analysis Based on Ensemble Empirical Mode Decomposition
(2013-01-01)
Kao, Sheng-Chi
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Hsiao, Tzu-Chien
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Chang, Chia-Chi
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Hsu, Hung-Yi
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分子醫學與生物工程研究所
In recent studies, the reflection waveform analysis (RWA) in arterial blood pressure (ABP) is the important method for cardiovascular system assessment. But conventional RWA contains some limitations during several clinical experiments, such as the unrecognizable reflection waveform morphology during Valsalva maneuver (VM). This study proposed a new RWA based on ensemble empirical mode decomposition (EEMD), which extracted the intrinsic feature of ABP waveform, including reflection wave and trend of ABP. Furthermore, the reflection time (T-r) was computed by EEMD-based RWA and the results of agreement test showed that T-r can be estimated with unrecognizable reflection waveform. It helps for the cardiovascular system assessment during specific physiological challenges, such as VM. Moreover, it helps for cardiovascular auto-regulation studies for reflection wave monitoring by VM study.
Spectral Analysis of Photoplethysmography Based on EEMD Method
(2015)
Chuang, Shang-Yi
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Liao, Jia-Ju
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Chou, Chia-Ching
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Chang, Chia-Chi
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Fang, Wai-Chi
In this paper, the proposed algorithm based on Hilbert-Huang Transform (HHT) is used to analyze the photoplethysmography (PPG) signal. In fact, PPG is nonlinear and nonstationary signal which is suitable for HHT method to achieve the capability of precise decomposition. The time series data are decomposed into Intrinsic Mode Function (IMF) with Ensemble Empirical Mode Decomposition (EEMD) algorithm. This study proposed a novel instantaneous pulse rate variability (iPRV) measurement based on EEMD method to analyze the very high frequency band (0.4-0.9Hz) of IMF5 which contains heart rhythm component.
The Analysis of Service Acceptance Framework for Social Games Based on Extensive Technology Acceptance Model
(2010)
Chen, Po-Yu
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Chang, Chia-Chi
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管理科學系
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Department of Management Science
The social networking website has been one of the most popular Internet websites in recent years. Lately social games such as "happy farm" drew a lot of attentions and accumulated millions of players in short period of time. The popularity of social games is changing the ecosystem of online games. Companies in this industry have to be concerned about the impact of it to keep their competitiveness. Technology acceptance model (TAM) has been pervasively used by researchers in that this model systematically helps the users to find out the process of user behaviors, and explores the impact of external variables which change the attitude and desire of users to adopt new technologies. This study reviewed the behaviors of social game players and used "perceived enjoyment", "perceived attractiveness", "social norms", and "platform service and corporate image" as the external variables and "intention toward playing social games", "customer preference", "customer loyalty" as the dependent variables in the TAM for social games. DEMATEL is used as the analysis tool in this study. The result shows that "social norms" and "perceived enjoyment" are the top two factors that can help to improve the popularity of social games. This study provides a reference to the companies in social game business and helps them to offer a more popular social game to players.
The effects of service recovery and relational selling behavior on trust, satisfaction, and loyalty
(2018-01-01)
Chang, Chia-Chi
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Hung, Jung-Sung
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交大名義發表
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National Chiao Tung University
Purpose - The purpose of this paper is to investigate the relationship between service recovery and relational selling behavior on trust and satisfaction in the banking industry. Specifically, the mediating role of trust and satisfaction on the relationship between service recovery, relational selling behavior and loyalty is empirically examined. Design/methodology/approach - Hypotheses are developed based on the literature review. The conceptual model is tested using SEM on survey data collected from 560 customers of 12 banks in Taiwan, including local banks and foreign banks. Findings - The model test results indicate that the influences of service recovery and relational selling behavior on trust and satisfaction are both significant. In addition, the influences of trust and satisfaction on loyalty are significant. Practical implications - For bank managers, it is crucial to have well programs to identify service failures and handle recoveries efficiently and effectively. Furthermore, bank managers should place a high value on increasing salesperson's customer-oriented behaviors to discern potential problems that customer concerns and provide suitable solutions that customer needs. By creating these better customer experiences, greater trust, satisfaction and loyalty can be yielded. Originality/value - This study aims to provide a superior understanding of the relationship between service recovery, relational selling behavior, trust, satisfaction and loyalty in the banking industry. The research findings can contribute to forming targeted strategies and gaining competitive advantages for bank managers.
The Interplay between Customer Participation and Difficulty of Design Examples in the Online Designing Process and Its Effect on Customer Satisfaction: Mediational Analyses
(2009-04-01)
Chang, Chia-Chi
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Chen, Hui-Yun
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Huang, I-Chiang
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管理科學系
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Department of Management Science
In the current consumer-centric economy, consumers increasingly desire the opportunity to design their own products in order to express more effectively their self-image. Mass customization, based on efficient and flexible modulization designs, has provided individualized products to satisfy this desire. This work presents an experiment employed to demonstrate that customer participation leads to higher satisfaction. Specifically, the increment in customer satisfaction due to participation is greater when an easy example is provided than when either no example or a difficult one is provided. Additionally, self-congruity plays a mediating role on the customer participation-satisfaction relationship, and this mediating effect varies across different levels of the design example provided in the design process. When an easy design example is present, customer participation has a direct effect on satisfaction, in addition to the indirect effect of self-congruity. When a difficult example is provided, customer participation does not have incremental effects on either self-congruity or customer satisfaction. Finally, when no design example is shown to customers, contrary to our expectation, participation still enhances customer satisfaction due to an increased sense of self-congruity.
The interpretation of very high frequency band of instantaneous pulse rate variability during paced respiration
(2014-04-21)
Chang, Chia-Chi
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Hsu, Hung-Yi
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Hsiao, Tzu-Chien
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分子醫學與生物工程研究所
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資訊工程學系
Background: Pulse rate (PR) indicates heart beat rhythm and contains various intrinsic characteristics of peripheral regulation. Pulse rate variability (PRV) is a reliable method to assess autonomic nervous system function quantitatively as an effective alternative to heart rate variability. However, the frequency range of PRV is limited by the temporal resolution of PR based on heart rate and it is further restricted the exploration of optimal autoregulation frequency based on spectral analysis. Methods: Recently, a new novel method, called instantaneous PRV (iPRV), was proposed. iPRV breaks the limitation of temporal resolution and extends the frequency band. Moreover, iPRV provides a new frequency band, called very high frequency band (VHF; 0.4-0.9 Hz). Results: The results showed that the VHF indicated the influences of respiratory maneuvers (paced respiration at 6-cycle and 30-cycle) and the nonstationary condition (head-up tilt; HUT). Conclusions: VHF is as a potential indication of autoregulation in higher frequency range and with peripheral regulation. It helps for the frequency exploration of cardiovascular autoregulation.