• Title/Summary/Keyword: Mixed-effect modeling

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Three Qualities of OTT Services: A Mixed Methods Approach (OTT 서비스의 세 가지 질적 요소: 혼합적 연구방법을 통한 접근)

  • Jae Sun Yoo;Jaecheol Park;Hyun Jun Jeon;Jai-Yeol Son
    • Information Systems Review
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    • v.24 no.1
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    • pp.59-87
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    • 2022
  • Since over-the-top (OTT) service has emerged as a new way of consuming video contents, OTT markets grow exponentially and the competition among the OTT services becomes intense. Only limited systematic research effort has been paid to understand why users subscribe such OTT services among other services. Therefore, we used developmental sequential mixed methods approach to find out the quality factors and their effect on post-subscription experiences and continuance intention. In the qualitative study, we derived six factors which a user considers important to continue the subscription. Based on the explored factors, we hypothesized a research model with modified three qualities from ISSM. The proposed research model was validated through quantitative research, a survey of 226 OTT service users in South Korea, using structural equation modeling. The results indicated that content quality is the key factor affecting both perceived enjoyment and satisfaction whereas system quality affects satisfaction, and service quality only affects enjoyment. Enjoyment affects satisfaction which sequentially affects continuance usage intention. This study contributes to research by modifying ISSM through mixed methods. It also provides OTT service providers with insight to enhance users' post experience and continuance intention to use the service through qualities derived from the interview.

The Assessment on the Sound Quality of Reduced Frequency Selectivity of Hearing Impaired People (난청인의 주파수 선택도 둔화현상이 음질에 미치는 영향 평가)

  • An, Hong-Sub;Park, Gyu-Seok;Jeon, Yu-Yong;Song, Young-Rok;Lee, Sang-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1196-1203
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    • 2011
  • The reduced frequency selectivity is a typical phenomenon of sensorineural hearing loss. In this paper, we compared two modeling methods for reduced frequency selectivity of hearing impaired people. The two models of reduced frequency selectivity were made using LPC(linear prediction coding) algorithm and bandwidth control algorithm based on ERB(equivalent rectangular bandwidth) of auditory filter, respectively. To compare the effectiveness of two models, we compared the result of PESQ (perceptual evaluation of speech quality) and LLR(log likelihood ratio) using 36 Korean words of two syllables. To verify the effect on noise condition, we mixed white and babble noise with 0dB and -3dB SNR to speech words. As the result, it is confirmed that the PESQ score of bandwidth control algorithm is higher than the score of LPC algorithm, on the other hands, and the LLR score of LPC algorithm is lower than the score of bandwidth control algorithm. It means that both non-linearity and widen auditory filter characteristics caused by reduced frequency selectivity could be more reflected in bandwidth control algorithm than in LPC algorithm.

Regional Science and Technology Resource Allocation Optimization Based on Improved Genetic Algorithm

  • Xu, Hao;Xing, Lining;Huang, Lan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.4
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    • pp.1972-1986
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    • 2017
  • With the advent of the knowledge economy, science and technology resources have played an important role in economic competition, and their optimal allocation has been regarded as very important across the world. Thus, allocation optimization research for regional science and technology resources is significant for accelerating the reform of regional science and technology systems. Regional science and technology resource allocation optimization is modeled as a double-layer optimization model: the entire system is characterized by top-layer optimization, whereas the subsystems are characterized by bottom-layer optimization. To efficaciously solve this optimization problem, we propose a mixed search method based on the orthogonal genetic algorithm and sensitivity analysis. This novel method adopts the integrated modeling concept with a combination of the knowledge model and heuristic search model, on the basis of the heuristic search model, and simultaneously highlights the effect of the knowledge model. To compare the performance of different methods, five methods and two channels were used to address an application example. Both the optimized results and simulation time of the proposed method outperformed those of the other methods. The application of the proposed method to solve the problem of entire system optimization is feasible, correct, and effective.

Effects of usage motivation for omni-channel services on continuance and affective commitment and brand purchase intention (옴니채널 서비스 이용 동기가 지속적 몰입과 정서적 몰입 및 브랜드 구매의도에 미치는 영향)

  • Choi, Mi Young
    • The Research Journal of the Costume Culture
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    • v.27 no.6
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    • pp.553-568
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    • 2019
  • This study examined motivation to use omni-channel services on mobile devices in fashion stores and the effects of such usage motivation on brand purchase intention through continuous and affective commitment. Data were collected on consumers in their 20s and 30s who experienced omni-channel services during shopping for or purchasing fashion products. An online survey asked 413 consumers to rate their brand purchase intention. Sub-levels of each variable were examined using SPSS 25.0, followed by confirmatory factor analysis using AMOS 19.0. In addition, path analysis using structural equation modeling was applied to analyze associations between variables. The statistical results were mixed. First, only two dimensions of usage motivation for omni-channel services, hedonic and relational motivation, had positive effects on continuous and affective commitment. Second, continuous commitment had a greater effect on purchase intention of brands that provided omni-channel services than it did on affective commitment. Third, of the dimensions of usage motivation, utilitarian motivation had a direct influence on purchase intention in the modified model, while social motivation did not affect service commitment and purchase intention. Finally, our findings suggest that brand loyalty can be built by encouraging service commitments through hedonic and relational motivation, based on the usability of omni-channel services.

Incompressible smoothed particle hydrodynamics modeling of thermal convection

  • Moballa, Burniadi;Chern, Ming-Jyh;Odhiambo, Ernest
    • Interaction and multiscale mechanics
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    • v.6 no.2
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    • pp.211-235
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    • 2013
  • An incompressible smoothed particle hydrodynamics (ISPH) method based on the incremental pressure projection method is developed in this study. The Rayleigh-B$\acute{e}$nard convection in a square enclosure is used as a validation case and the results obtained by the proposed ISPH model are compared to the benchmark solutions. The comparison shows that the established ISPH method has a good performance in terms of accuracy. Subsequently, the proposed ISPH method is employed to simulate natural convection from a heated cylinder in a square enclosure. It shows that the predictions obtained by the ISPH method are in good agreements with the results obtained by previous studies using alternative numerical methods. A rotating and heated cylinder is also considered to study the effect of the rotation on the heat transfer process in the enclosure space. The numerical results show that for a square enclosure at, the addition of kinetic energy in the form of rotation does not enhance the heat transfer process. The method is also applied to simulate forced convection from a circular cylinder in an unbounded uniform flow. In terms of results, it turns out that the proposed ISPH model is capable to simulate heat transfer problems with the complex and moving boundaries.

Critical Factors Influencing Revisit Intention of Large Restaurant Chains in Myanmar

  • LAMAI, Gam Hpung;THAVORN, Jakkrit;KLONGTHONG, Worasak;NGAMKROECKJOTI, Chittipa
    • Journal of Distribution Science
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    • v.18 no.12
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    • pp.31-43
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    • 2020
  • Purpose: This study examined how many determinant factors (service dimensions, food quality, and price perception) affect revisit intention. This practical concept is service quality (SERVQUAL), customer satisfaction, and repeated/revisit behavioral intention based on the theory of reasoned action (TRA). Research design, data and methodology: This research applied a hybrid mixed-method comprising exploratory and explanatory sequential design by Creswell (2014). The 400 responses were collected in four townships in Myanmar. This study drilled down to exploratory factor analysis (EFA) followed by confirmatory factor analysis (CFA) prior to test the hypothesized factor structure of all the variables resulted in the form of the goodness of fit. For further data analysis, structural equation modeling (SEM) was applied to test the relationships among the variables of the proposed model. Results: The results showed that perceived service quality, food quality, and price perception have direct effects on customer satisfaction and indirect effect on revisit intention. The perceived service quality has the most significant influence while the food quality has the least influence on customer satisfaction. Conclusions: The results are useful for the restaurant managers to better understand the significant strategic choice factors to improve higher quality service amongst restaurants both domestic and international under the stiff competition.

Determinants of Investment in the Jordanian Productive Sectors

  • ABU-LILA, Ziad Mohammad
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.635-641
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    • 2021
  • This paper aims to find out the main factors that are important in determining the size of investment in the Jordanian productive sectors. For this purpose, the study used panel data for four Jordanian productive sectors over the period 2000-2017. Also, fixed-effects modeling was carried out to identify the relationship between investment and its potential determinants. Empirical investigations of the four productive sectors reveal the following results: The real value of sector's production and the real value of credit facilities have a positive and significant impact on investment, while the real interest rate has a negative effect on investment in the Jordanian productive sectors. Also, at the sector level, agriculture was more responsive to changes in the real value of credit facilities, while other sectors were more responsive to changes in the real value of sector's production. According to these results, it seems that some policy actions should be taken to enhance the size and the role of investment in the economy. For example, policymakers should adopt a mixed policy and expand the provision of credit facilities, especially to the agricultural sector, to enhance agricultural activity in a manner that ensures the improvement of infrastructure and land reclamation.

The Effect of Occupational Noise Exposure on Serum Cortisol Concentration of Night-shift Industrial Workers: A Field Study

  • Zare, Sajad;Baneshi, Mohammad R.;Hemmatjo, Rasoul;Ahmadi, Saeid;Omidvar, Mohsen;Dehaghi, Behzad F.
    • Safety and Health at Work
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    • v.10 no.1
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    • pp.109-113
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    • 2019
  • Background: In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift. Methods: This case-control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with ${\alpha}=0.05$. Results: The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62). Conclusion: Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.

Silicon Substrate Coupling Modeling and Analysis including RF Package Inductance (RF 패키지 인덕턴스가 실리콘 기판 커플링에 미치는 영향 모델링 및 해석)

  • Jin, U-Jin;Eo, Yeong-Seon;Sim, Jong-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.1
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    • pp.49-57
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    • 2002
  • Including RF Package inductance, substrate coupling through conductive silicon(Si)-substrate is modeled and quantitatively characterized. 2-port substrate coupling model is extended for the characterization of multi-port substrate coupling between digital circuit block and analog/RF circuit block. Furthermore, scalable parameter extraction model is developed. Multi-port substrate coupling can be investigated by linearly superposing a frequency-dependent 2-port substrate coupling model using scalable parameters. In addition, Substrate coupling including RF package inductance effect is quantitatively investigated. It is shown that package effect increases substrate coupling and shifts a characteristic frequencies(i.e., poles) to the higher frequency range. The proposed methodology can be efficiently used to the mixed-signal circuit performance verification.

A Systematic Study on the Effect of Social StoryTM Intervention for Individual with Autism Spectrum Disorder (자폐스펙트럼장애 아동을 위한 상황이야기 중재의 효과 연구에 대한 체계적 고찰)

  • Bae, Won-Jin;Park, Ju-Young
    • Journal of The Korean Society of Integrative Medicine
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    • v.9 no.2
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    • pp.131-140
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    • 2021
  • Purpose : The purpose of this study was to systematically review the studies on the effects of social story intervention on the individuals with autism spectrum disorders(ASD) to provide the basis for evidence-based practice. Methods : In order to find out the studies on the effect of social story intervention on individuals with ASD, studies published from 2011 to December 2020 were searched on Google Academic Search. The keywords used were "autism spectrum disorder AND social story". A total of 16,900 studies were searched, and from these, 12 studies were selected based on the application of the selection and exclusion criteria. The included studies comprised of 10 single subject design studies and 2 randomized controlled trials design studies. The included studies were analyzed in accordance to population, intervention, outcome measures and results. Results : As a result of analysing the subjects of the included studies, we found out that pre-school children and adolescents were the most common groups of individuals diagnozsed with ASD. In addition to ASD, the diagnosis of the subjects included intellectual disability, Asperger, and Prader-willi. We found out that there were more interventions that were mixed with other interventions, than just the pure social story interventions. In particular, video modeling was found to be the most frequent intervention. This was followed by photo-based social stories. For outcome measure, autism social skills profile was found to be the most often used standardized assessment. For a non-standardized assessment, social desired behavior was found to be the most frequently evaluated behavior, followed by personal problem behavior. Of all the dependent variables, the dependent variable reported as "effective" was the most, followed by "some effective". Conclusion : This study is organized to help the individuals with ASD, families, researchers, and therapists understand the effects of social story intervention on the individuals with ASD in an easy fashion. Further, therapists can use this study as the basic data for evidence-based practice.