• Title/Summary/Keyword: Hypothesis Tests

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Nonlinear Conte-Zbilut-Federici (CZF) Method of Computing LF/HF Ratio: A More Reliable Index of Changes in Heart Rate Variability

  • Vernon Bond, Jr;Curry, Bryan H;Kumar, Krishna;Pemminati, Sudhakar;Gorantla, Vasavi R;Kadur, Kishan;Millis, Richard M
    • Journal of Pharmacopuncture
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    • v.19 no.3
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    • pp.207-212
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    • 2016
  • Objectives: Acupuncture treatments are safe and effective for a wide variety of diseases involving autonomic dysregulation. Heart rate variability (HRV) is a noninvasive method for assessing sympathovagal balance. The low frequency/high frequency (LF/HF) spectral power ratio is an index of sympathovagal influence on heart rate and of cardiovascular health. This study tests the hypothesis that from rest to 30% to 50% of peak oxygen consumption, the nonlinear Conte-Zbilut-Federici (CZF) method of computing the LF/HF ratio is a more reliable index of changes in the HRV than linear methods are. Methods: The subjects of this study were 10 healthy young adults. Electrocardiogram RR intervals were measured during 6-minute periods of rest and aerobic exercise on a cycle ergometer at 30% and 50% of peak oxygen consumption ($VO_{2peak}$). Results: The frequency domain CZF computations of the LF/HF ratio and the time domain computations of the standard deviation of normal-to-normal intervals (SDNN) decreased sequentially from rest to 30% $VO_{2peak}$ (P < 0.001) to 50% $VO_{2peak}$ (P < 0.05). The SDNN and the CZF computations of the LF/HF ratio were positively correlated (Pearson's r = 0.75, P < 0.001). fast Fourier transform (FFT), autoregressive (AR) and Lomb periodogram computations of the LF/HF ratio increased only from rest to 50% $VO_{2peak}$. Conclusion: Computations of the LF/HF ratio by using the nonlinear CZF method appear to be more sensitive to changes in physical activity than computations of the LF/HF ratio by using linear methods. Future studies should determine whether the CZF computation of the LF/HF ratio improves evaluations of pharmacopuncture and other treatment modalities.

Mediating Effect of Academic Self-efficacy in the Relationship between the Grit of Teens and Self-directed Learning (청소년의 그릿과 자기주도 학습의 관계에서 학업적 자기효능감의 매개효과)

  • Kim, Eun Im
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.665-674
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    • 2020
  • This study determined the relationship between grit and self-regulated learning in South Korean teens in order to gain an understanding of grit, which is still at the beginning stage of the research, and to obtain implications for Korean learners' self-directed learning. This study also clarified the process by which learners are involved in selecting effective goals for self-directed learning and to provide cognitive efficacy for learners to encourage efforts to achieve their goals. This study was conducted over the period of 4 weeks, and was mainly targeted at the middle-school and high-school boys and girls in Daejeon, Sejong and Cheonan by using 376 collected survey questionnaires. Confirmatory factor analysis, reliability analysis, correlation analysis, structural equation, and Sobel-tests were performed using SPSS 23.0 and AMOS 23.0 for the data analysis. The hypothesis test results of this study are as follows. First, the grit of teens had a positive influence on their academic self-efficacy. Second, the grit of teens had a positive influence on their self-directed learning. Third, academic self-efficacy of teens was found to have a positive effect on their self-directed learning. Fourth, academic self-efficacy of the teens had a mediating effect in the relationship between the teens' grit and self-directed learning.

The study for the Epidemiologic Characteristics of Cancer Patients in Jeju Special Self-governing Province (제주특별자치도 암 환자의 역학적인 특성에 관한 연구)

  • Chang, Weon-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.2
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    • pp.1292-1303
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    • 2015
  • Jeju province is the highest area about obesity(1st), alcohol consumption(2nd) and male smoking(2nd) among sixteen Korean provinces by the report of Statistics Korea: 2013 community health survey. Therefore, it is assumed that the incidence rate of colon, liver, lung and breast cancer can be high. The purpose of this study is to test these cancer's incidence and mortality trends and compare comparability with national average. The Joinpoint regression model and permutation tests for identifying changes and parallelism in trend were used to test registered data at Jeju Regional Cancer Registry from 1999 to 2012. In male colorectal cancer, Average Age Percent Change(AAPC) of Age-Standardized incidence Rate(ASR) was 8.4% per year(p-value<.000) and the hypothesis of parallelism with Korean male average was rejected because of steep increasing of Jeju male patients' AAPC(p-value=.047). In male liver cancer, AAPC of ASR was -2.98 % per year(p-value<.000) and parallelism with Korean male average was rejected because of sluggish decreasing of Jeju(p-value=.026). In male lung cancer, the ASR parallelism with Korean male average was rejected(p-value=.009) because Jeju patients APC(4.37% per year) was increased during 2006~2012. This study demonstrates that AAPC and Trends of male colon, male lung and male liver were difference from national average. Further studies are needed to understand its causes.

A Study on the Effects of factor of Service Quality, Service Guarantee and Service Value in General Super Market. (종합슈퍼마켓(GSM)에서 서비스품질, 보증 및 서비스가치의 영향요인에 관한 연구)

  • Kim, Jong-Lak
    • Journal of Distribution Science
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    • v.13 no.1
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    • pp.93-103
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    • 2015
  • Purpose - This study plans to adopt a more sophisticated approach toward service recognition by customers in general supermarkets in order to revise the service quality measurement methods that suit the context of Korean distribution channels. In particular, in general supermarkets, where much of the shopping process is in the form of self-service, there is high reliance on the service recognized by the consumers; therefore, it is highly likely that consumers would make their purchasing decisions based on their recognition of service quality or guarantees. It also utilized service quality elements of a basic level in the KD-SQS development model in order to indicate that the quality recognized by consumers impacts their loyalty to the stores with financial value and abstract value. Research design, data, and methodology - The study suggested a theoretical model comprising 13 hypotheses on relations between theoretic variables, and conducted surveys with consumers using discount stores in Seoul and Gyunggi Metropolitan area in order to verify the hypotheses, while using SPSS 20.0, AMOS 21.0 as the verification program. The survey sheets used amounted to 332, and a structural equation model was used to analyze the reliability and validity of constituent elements and to verify the suggested hypothesis. Therefore, this study analyzes the interrelations between service quality and guarantee factors in the distribution channel and their relations with the loyalty to stores as a dependent variable. Results - First, the results of the hypotheses tests helped identify the relations between service quality, service guarantees, service value, and customer loyalty, providing an opportunity to define the relations between constituent elements. In particular, service convenience in service quality has no impact on financial values. Further, stores' service policy had no impact on abstract values. Service recognition by service convenience has an impact on abstract values such as good image, comfort, and usability, while mileage systems promote financial values for consumers. In order to improve consumer values in service quality and values, general supermarkets should improve their service convenience, membership, and mileage programs using various strategies. Conclusion - In order to improve consumer values in service quality and values, general supermarkets should improve their service convenience, membership, and mileage programs using various strategies. Further, as service guarantee systems have a significant and direct impact on customer loyalty, rather than customer value recognition, service guarantees should be used to encourage customers to re-visit the stores. Finally, this study applied the findings of preceding studies in terms of service quality measurement; it had limitations in referencing preceding studies in a comprehensive manner. It also had limits in expanding upon various preceding studies because it was difficult to apply new measurement tools due to the lack of service quality measurement tools for general supermarkets. Therefore, it is necessary to conduct more studies on service quality to measure service quality and develop measurement tools by incorporating various industry characteristics.

Analysis of Export Behaviors of Busan, Incheon and Gwangyang Port (부산항, 인천항, 광양항의 수출행태분석)

  • Mo, Soowon;Chung, Hongyoung;Lee, Kwangbae
    • Journal of Korea Port Economic Association
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    • v.32 no.3
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    • pp.35-46
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    • 2016
  • This study investigates the export behavior of Busan, Gwangyang and Incheon Port. The monthly data cover the period from January 2000 to December 2015. We employ six export functions composed of various exchange rates and industrial production index. This paper finds that the nominal effective exchange rate is more appropriate for explaining the export behaviors of the three ports, regardless of the narrow and wide indices which comprise 26 and 61 economies for the nominal and real indices respectively. This paper tests whether exchange rate and industrial production are stationary or not, rejecting the null hypothesis of a unit root in each of the level variables and of a unit root for the residuals from the cointegration at the 5 percent significance level. The error-correction model is estimated to find that both Gwangyang and Incheon ports are much slower than Busan port in adjusting the short-run disequilibrium and Gwangyang port is a little slower than Incheon port. The rolling regressions show that the influence of exchange rate as well as industrial production tends to decrease in all of three ports. The variance decomposition, however, shows that the export variables are very exogenous and the export of Busan Port is the least exogenous and that of Gwangyang Port the most. This result indicates that the economic variables such as exchange rate and economic activity affect the export of Busan Port more strongly than that of Gwangyang and Incheon Port.

Mediating effect of job embeddedness between positive psychological capital and organizational citizenship behavior (긍정심리자본과 조직시민행동간 직무배태성의 매개효과)

  • Han, Jin-Hwan
    • Journal of Digital Convergence
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    • v.19 no.9
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    • pp.105-114
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    • 2021
  • The paper investigates a mediating effect of job embeddedness in the influence of positive psychological capital on organizational citizenship behavior(OCB) for members of medical institutions. The members include medical doctors, nurses, medical technicians, health administrative staffs, and other medical service staffs of hospitals in Daejeon City, Chungcheongnam-do, Chungcheongbuk-do, and Sejong City. Using 453 questionnaires for hypothesis tests, the main results are as follows. Firstly, positive psychological capital exerts a significantly positive effect on OCB. Secondly, the fit and links of job embeddedness turn out to have a significant and positive effect on OCB, whereas the sacrifice does not have statistically significant effect on it. Thirdly, while the fit and links of job embeddedness appear to have mediating effects between positive psychological capital and OCB, the sacrifice of it does not exert a mediating effect. The findings thus suggest that we need a new approach to the role of job embeddedness in the positive impacts of positive psychological capital on OCB through the fit and links of job embeddedness. Furthermore, organizations need to focus on key elements in the application of job embeddedness.

The Effect of Humane Entrepreneurship on the Core Competencies and Corporate Performance of SMEs (사람중심 기업가정신이 중소기업 핵심역량과 기업성과에 미치는 영향)

  • Kim, Kwang-Hyun;Dong, Hak-Lim
    • The Journal of the Korea Contents Association
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    • v.19 no.5
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    • pp.217-232
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    • 2019
  • As the role of entrepreneurship has become more important for continuous business growth in a rapidly changing economic environment, numerous studies dealing with entrepreneurship are taking place. However, recent studies has concentrated mainly on business-oriented entrepreneurship which emphasizes corporate efficiency only. While in the era of fourth industrial revolution human resources are more important than corporate efficiency, the existing literature is largely focused on traditional entrepreneurship. Research on humane entrepreneurship has not been rigorous, and there are few studies involving small and medium-size enterprises (SMEs) in particular. The purpose of this study is to fill in this void by investigating the effect of humane entrepreneurship on core competencies of SMEs and the effect of these core competencies on corporate performance. To examine SMEs core competencies and their performance from the perspective of humane entrepreneurship, this study set up traditional entrepreneurship and humane entrepreneurship as variables, and develop research model based on these variables. This study tests 5 different hypothesis using this model. A survey was conducted among CEOs and executives at SMEs in Seoul and Gyeonggido, South Korea from, June 26 to August 1, 2018. A total of 310 questionnaires were analyzed. The results show that both traditional and human entrepreneurship have a positive effect on the core competencies of SMEs, which are core competency factors, and that core competencies positively affect both non-financial performance and financial performance. Moreover, non-financial performance is found to have positive effect on financial performance. Given these findings, this study suggests that humane entrepreneurship is critical to SMEs and their performance, no less than traditional entrepreneurship. This study provides profound implications of necessity of raising humane entrepreneurship in environment of companies.

Studies on Derivation of Appropriate Geodetic System Transformation Schemes for Spatial Data (공간정보의 측지기준체계 변환 기법 도출에 관한 연구)

  • Yun, Seonghyeon;Lee, Hungkyu;Song, Jinhun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.38 no.6
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    • pp.561-571
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    • 2020
  • Seven techniques widely used in the geodetic transformations have been reviewed and compared to figure out their theoretical characteristics. A series of numerical tests were performed about four data sets. This was followed by result analyses in terms of transformation residuals and accuracies together with some hypothesis testings based on the student-t distribution to confirm the statistical significance of the techniques. In the case of the transformation between the geodetic frames implemented in the same system, no statistical significance was revealed in the results of the 3D transformation techniques, even if the testing area becomes large as the Asia-Oceania continent. Among the 2D transformations, it was possible for the NTv2 grid modeling technique to deliver improved transformation accuracy. Finally, it was possible from the results analyzed in this study to propose the Helmert transformation to geodetic control points and the NTv2 technique to the 2D spatial data transformation of the geodetic systems.

The Effect of Guided Autobiography on Ego-Integrity, Depression and Life Satisfaction and the Heuristic Meaning in the Elderly (집단 자서전쓰기가 노년기 자아통합, 우울 및 생활만족도에 미치는 효과와 체험적 의의)

  • Lyu, Jung In;Cho, Haekyung;Kim, Byung Suk
    • 한국노년학
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    • v.32 no.2
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    • pp.559-576
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    • 2012
  • This research aims to address the effect of Guided Autobiography(GAB) on ego-integrity, depression and life-satisfaction in the elderly and to investigate psychological changes and experiences on the senior subject. 20 subjects participated weekly autobiography writing sessions in a senior academy in the S city for 13 weeks. In this research, we carried out examination on ego-integrity, depression test, and life-satisfaction survey were performed before and after the writing sessions for a quantitative analysis, which was later investigated through a 'corresponding sample T-test'. Based on the results of the above mentioned tests, the qualitative analysis was conducted through an individual sessions with 5 selected participants. The results of this research are summarized as following. First, ego-integrity showed satisfactorily meaningful difference between pre- and post-GAB writing. The participants recollected the past repent and revisited unresolved issues in their lives. The subjects were able to accept these past misdemeanors and appreciate their lives. GAB indeed helped improving ego-integrity. Second, the hypothesis that GAB writing will help decrease depression was accepted. 2-page weekly writing assignments enabled the participants think of joyful moments in their past, and showed decrease the symptoms of depression. Third, this study revealed that GAB writing improved life- satisfaction. The participants learned to express gratitude and peace in their mind. The happy feeling and optimistic thoughts enhanced their satisfaction of life in turn. In addition, it turned out that the effects of GAB were more drastic in group sessions than in individual writings. Interpersonal interactions in group sessions encouraged the exchange of positive feedback, thereby helping them reflect themselves positively.

A Study on the Apple Watch Satisfaction and Continuous Use Intention : Evidence from the Chinese Market (애플워치 만족도와 지속적 사용의도에 대한 실증연구 : 중국시장을 중심으로)

  • Ruan, Jing-kun;Song, Hyo-jung;Kim, Tae-ha
    • Journal of Venture Innovation
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    • v.6 no.3
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    • pp.73-93
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    • 2023
  • This study provides a prospect for the fast growing the smartwatch market by investigating the relationship between the satisfaction and the continuous use intention of Apple watch users, as well as the factors influencing their satisfaction. Based on the TAM, this study uses system quality, information quality, and self-efficacy as independent variables, perceived usefulness, perceived ease of use, and satisfaction as mediators, and continuous use intention as the dependent variable. We analyze the data of 256 individuals who completed an online survey with SPSS 26.0 and AMOS 26.0 software. This study conducts several tests and analyses to empirically evaluate the data including reliability analysis, factor analysis, feasibility analysis, path analysis, hypothesis verification, and mediation analysis. Our results investigate which factors may influence consumers' intention to continuously using Apple Watch devices in the future. In summary, satisfaction has a positive effect on the intention to continuously use smartwatchs. Perceived usefulness and perceived ease of use have a positive effect on satisfaction. Among the three factors (system quality, information quality, and self-efficacy), only self-efficacy has no significant impact on perceived usefulness but had a positive effect on perceived ease of use. In addition, system quality and information quality positively affect perceived usefulness, perceived ease of use, satisfaction, and continuous intention to use an Apple Watch. Taking the Apple Watch as the subject of our research topic, this study provides theoretical value by exploring the impact of user's satisfaction with their smartwatch on their continuous usage intention. This study further explains the influence of system quality, information quality, and self-efficacy on user satisfaction. Additionally, this research offers valuable insight to practitioners by confirming that information quality, system quality, and self-efficacy are important features for enhancing satisfactory user experiences which in turn may increase users' intention to continued using smartwatches.