• The Korean Journal of Applied Statistics
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• v.23 no.3
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• pp.559-571
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• 2010

The Demand-Control model has been one of the most popular theoretical models to explain job stress. This study extends the Demand-Control model to the team level and examines the relationship between job demand and job stress to tests the moderating effect of the `team relationship climate' on the relationship between job demand and job stress. Data were collected from 34 teams across 19 organizations and analyzed using HLM. The results showed that job demand was significantly related to job stress. Based on the team level analysis, the team relationship climate was found to moderate the relationship between job demand and job stress. In addition, the consideration behavior by the leader was significantly correlated with the team relationship climate. Finally the theoretical and practical implications and limitations of this study were discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2900-2922
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• 2021

In this paper, the power spectral density(PSD) for Multilevel Minimum Shift Keyed signal with modulation index h = 1/2 (M-ary MSK) are derived using the mathematical method of the Markov Chain model. At first, according to an essential requirement of the phase continuity characteristics of MSK signals, a complete model of the whole process of signal generation is built. Then, the derivations for autocorrelation functions are carried out precisely. After that, we verified the correctness and accuracy of the theoretical derivation by comparing the derived results with numerical simulations using MATLAB. We also divided the spectrum into four components according to the derivation. By analyzing these figures in the graphic, each component determines the characteristics of the spectrum. It is vital for enhanced spectral characteristics. To more visually represent the energy concentration of the main flap and the roll-down speed of the side flap, the specific out-of-band power of M-ary MSK is given. OMLCD(Optimum Maximum Likelihood Coherent Detection) of M-ary MSK is adopted to compare the signal received with prepared in advance in a code element T to go for the best. And M-ary MSK BER(Bit Error Rate) is compared with the same ary PSK (Phase Shift Keying) with M=2,4,6,8. The results show the detection method could improve performance by increasing the length of L(memory inherent) in the phase continuity.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.402-407
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• 2022

Statistical design of experiments was used to optimize the MOF-5 synthesis process. A mixture design was employed to optimize precursor concentration. The optimal composition of three chemical materials, terephthalic acid, zinc acetate dihydrate, and N,N-dimethylformamide for MOF-5 synthesis was determined by extreme vertices design methods as follows; 1 mol : 2.7 mol : 40 mol. A multilevel factorial design was selected to screen the significance of synthesis reaction conditions such as temperature, time, and stirring speed. Statistical analysis results suggested excluding stirring speed from further investigation. Using a central composition design, the synthesis time and temperature were optimized. The quadratic model equation was derived from 13 synthesis experiments. The model predicted that MOF-5 synthesized at 119 ℃ for 10.4 h had the highest crystallinity.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.437-449
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• 2014

In this study, we analyzed an effect of area-environmental factor on breast cancer screening rates using multi-level analysis. It was intended for the KNHANES-IV. Total subjects were 14338. Among them, 4143 subjects met the inclusion criteria. When we applied only empty Model, a variance of breast cancer screening rates was 0.061 in each region. When we applied Model with individual level variables, the variance was 0.034. However, when we applied both Model with individual level variables and Model with area level variables, the variance was 0.023. We drew applied only individual level variables parallel applied 3 regional variances which could explain variance of inspection of breast cancer up to 18.04% compared with applied only individual level variables. Area level variables could reduce a variance of region. This means besides individual level variables. The group can share a same thing and can effect to breast cancer screening rates. We need to discover factors which area level variables and suggest that make a standard for inspection of breast cancer.

• 한국사회정책
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• v.24 no.1
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• pp.33-66
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• 2017

Based on the premise that the systematic career process of workers in the general labor market was one of core elements of successful achievements and their establishment both at the individual and organizational level, this study set out to conduct empirical analysis of factors influencing the subjective career success of disabled workers in competitive employment at the multi-dimensional levels of individuals and organizations(corporations) and thus provide practical implications for the career management directionality of their successful vocational life with data based on practical and statistical accuracy. For those purposes, the investigator administered a structured questionnaire to 126 disabled workers at 48 companies in Seoul, Gyeonggi, Chungcheong, and Gangwon and collected data about the individual and organizational characteristics. Then the influential factors were analyzed with the multilevel analysis technique by taking into consideration the organizational effects. The analysis results show that organizational characteristics explained 32.1% of total variance of subjective career success, which confirms practical implications for the importance of organizational variables and the legitimacy of applying the multilevel model. The significant influential factors include the degree of disability, desire for growth, self-initiating career attitude and value-oriented career attitude at the individual level and the provision of disability-related convenience, career support, personnel support, and interpersonal support at the organizational level. The latter turned out to have significant moderating effects on the influences of subjective career success on the characteristic variables at the individual level. Those findings call for plans to increase subjective career success through the activation of individual factors based on organizational effects. The study thus proposed and discussed integrated individual-corporate practice strategies including setting up a convenience support system by reflecting the disability characteristics, applying a worker support program, establishing a frontier career development support system, and providing assistance for a human network.

• 한국노년학
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• v.36 no.3
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• pp.581-594
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• 2016

This study aims to observe the effect of age friendliness of cities on life satisfaction and to suggest ways to improve quality of life of older people. The secondary data sets were used in this study, which were '2014 Survey of Living Conditions and Welfare Needs of Korean Older People.' It's a nationwide data collected by the Korean Institute of Health and Social Affairs. A multilevel analysis model was used to analyze the data because the level of age friendliness has a hierarchical data structure. Results showed as follows: First, life satisfaction of older adults is affected by the level of age-friendliness of cities in which they live. Second, on the personal level, older people showed low life satisfaction when they are more older and have more chronic diseases and more depressed. On the contrary, life satisfaction of older adults increased when they have higher education and income. Third, on the city level, older people showed higher life satisfaction when they live in high employment rate area and participation rate of lifelong education. Cautions should be placed when interpret the result because the variables that represent the characteristics of age friendless of cities were constituted arbitrary. Based on the results, suggestions for improving the city environment age-friendly and implications for social welfare practice were provided.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.289-305
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• 2023

The rapid increase in the use of mobile devices is changing consumers' online shopping behavior. However, the difference in the effect on the conversion rate according to the time when consumers switch from a small screen to a large screen has not been sufficiently studied. In addition, the differences in the effect of device conversion on purchase performance according to the characteristics of each country's infrastructure have not been sufficiently studied. Against this background, this study aims to analyze whether the timing of switching from mobile devices to PC devices and the country's mobile Internet penetration rate are moderating the positive effect of device switching on purchase performance. For empirical analysis, Google Merchandise Store data was collected and 101,466 data from 130 countries were analyzed with a multilevel model. As a result of the analysis, consumers' device switching (i.e., mobile to PC) had a positive effect when it occurred in the middle of the consumer journey. However, it was analyzed that when device switching occurred at the later stage of the consumer journey, it had a negative effect on purchase performance. In addition, it was analyzed that the higher the mobile Internet penetration rate, the weaker the positive effect of consumer device conversion on purchase performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.230-238
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• 2018

The purpose of this study is to examine the effects of park type and inner elements of parks on the number of walking days of walking out of Ulsan Metropolitan City, And to make policy suggestions for them. The elderly people aged 65 and 1,274 persons or over in Ulsan Metropolitan City were selected as the subjects using the raw data of the 2015 community health survey. A multilevel analysis was conducted using a hierarchical linear model to find out the factors affecting the number of days of walking according to the level of regional level factor according to the five wards of Ulsan Metropolitan City. The number of walking days increased with the number of sports facilities and the number of walking days decreased with the number of amusement facilities mainly used by children. In the case of Jung-gu in Ulsan, the number of walking days was low even though the number of parks and the area of the park were large, In the case of Buk-gu, the number of walking was high even though the number of parks and the area of the park were small. Elderly people in Jung - gu, Ulsan metropolitan city are expected to need a health promotion project to promote walking, and it is necessary for seniors in Buk - gu, Ulsan Metropolitan City to make a good walking environment.