• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.478-487
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• 2014

The simplified performance analysis and initial configuration design are required for the successful development of UAV during the conceptual design, in which empirical formulas and trend equations are utilized for the UAV performance analysis. In the conceptual design phase various UAV configurations may be considered, however, it is very inefficient and unnecessary to consider all configurations for the conceptual design. In this study, the database for the fixed wing UAVs whose MTOW is between 50kg and 1,500kg was also constructed for the selection of configuration frequently used. The parametric analyses were performed for major performance parameters, and trend equations were developed through regression analyses for these individual performance parameters.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.47-56
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• 2017

Aseismic designs of pile-supported wharves are commonly performed utilizing simplified dynamic analyses, such as multi-mode spectral analyses. Simplified analyses can be useful for evaluating the limit state of structures. However, several pile-supported wharves, that have been damaged during past earthquakes, have shown that soil deformation and soil-pile dynamic interaction significantly affect the entire behavior of structures. Such behavior can be captured by performing nonlinear effective stress analyses, which can properly consider the dynamic interactions among the soil-pile-structure. The present study attempts to investigate the earthquake performance of a pile-supported wharf utilizing a three-dimensional numerical method. The damaged pile-supported wharf at the Kobe Port during the Hyogo-ken Nambu earthquake (1995) is selected to verify the applicability of the numerical modeling. Analysis results showed a suitable agreement with the observations on the damaged wharf, and the significant effect of excess pore pressure development and pile-soil dynamic interaction on the seismic performance of the wharf.

• Computational Structural Engineering
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• v.8 no.3
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• pp.113-122
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• 1995

The purpose of this study is to evaluate performance and safety of structures designed according to current seismic code or provisions (e.g., Uniform Building Code(UBC), NEHRP provisions, etc.) during lifetime of structures. The performance is represented in terns of reliability in this paper. To perform reliability analyses, a large number of time history response analyses for a given structure are usually required. In this study, to perform reliability analyses ground motions are generated based on nonstationary random process and structures are designed based on UBC. In this paper, responses of structures under a given earthquake is evaluated using dynamic nonlinear time history analyses and also an equivalent nonlinear system (ENS) with response scaling factors. The ENS system is described in the companion paper. Therefore, this paper evaluates the seismic performance of structures and also verify the accuracy of ENS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.497-505
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• 2022

Performance and hub vibratory load analyses for a lift-offset coaxial rotor are conducted using a rotorcraft comprehensive analysis code, CAMRAD II. The lift-offset coaxial rotor is trimmed to match the total rotor thrust(lift-offset coaxial rotor's thrust) or the individual rotor thrust(upper and lower rotor thrusts, respectively) in this study. The individual rotor's lift and torque, and effective rotor lift to drag ratio for the total rotor are investigated for various advance ratios and lift-offset values. The two result sets with different trim methods are similar to each other and they are correlated well with the wind-tunnel test results. Therefore, the present study using CAMRAD II validates successfully the aeromechanics modeling and analysis techniques for the lift-offset coaxial rotor.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.20-26
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• 2014

In this paper, yield stress, tangent modulus and failure strain were varied to ascertain the influence of impact response such as impact force histories and residual energy. And the buckling behavior of FML(Fiber Metal Laminates) were analyzed using numerical method. A number of analyses on FML and aluminum panel were conducted for shear and compression loading to compare the capability of stability. And to evaluate the static performance, static analysis has performed for box beam structure. Low-velocity impact analysis has performed on FML made of aluminum 2024 sheet and glass/epoxy prepreg layers. And the buckling and static performance of FML have been compared to aluminum using the analysis results. For the comparison of structural performance, similar analyses have been carried out on monolithic aluminum 2024 sheets of equivalent weight.

• The Korean Journal of Health Service Management
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• v.9 no.3
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• pp.81-93
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• 2015

Objectives : The objective of this study was to examine preceding variables that affect the dual commitment of outsourced employees working at hospitals and to analyze the influence of these variables on job performance. Methods : Data were collected from 461 outsourced employees, working at 7 general hospitals, which had introduced the outsourcing system, using a structured, self-administered questionnaires. Frequency, validity/reliability, correlation and path analyses were done for data analysis. Results : The results of the path analyses showed that both commitment to the hiring company and commitment to the client company (hospital) had statistically significant positive effects on job performance. Additionally, when the 'single measurement' approach was used, dual commitment had a larger positive effect, compared with the 'parallel approach.' Among the preceding variables, 'satisfaction for the job itself' was found to be the most important variable affecting dual commitment and job performance. Conclusions : In conclusion, to enhance the job performance of outsourced employees, it is important for management to examine and improve the various factors related to job satisfaction. Additonally, for outsourced employees to have organizational commitments to the hiring and client companies simultaneously, management should emphasize a sense of unity and share organizational values.

• Preventive Nutrition and Food Science
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• v.17 no.1
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• pp.71-77
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• 2012

Hangwa is a traditional food, corresponding to the current consumption trend, in need of marketing strategies to extend its consumption. Therefore, the purpose of this study was to analyze consumers’ consumption patterns and perception of Hangwa to increase consumption in the market. A questionnaire was sent to 250 consumers by e-mail from Oct 8~23, 2009 and the data from 231 persons were analyzed in this study. Statistical, descriptive, paired samples t-test, and importance-performance analyses were conducted using SPSS WIN 17.0. According to the results, Hangwa was purchased mainly 'for present' (39.8%) and the main reasons for buying it were 'traditional image' (33.3%) and 'taste' (22.5%). When importance and performance of attributes considered in purchasing Hangwa were evaluated, performance was assessed to be lower than importance for all attributes. The attributes in the first quadrant with a high importance and a high performance were ‘a sanitary process’, ‘a rigorous quality mark’ and ‘taste’, which were related with quality of the products. In addition, those with a high importance but a low performance were ‘popularization through advertisement’, ‘promotion through mass media’, ‘conversion of thought on traditional foods’, ‘a reasonable price’ and ‘a wide range of price’. In conclusion, Hangwa manufacturers need to diversify products and extend the expiration date based on technologies to promote its consumption. In terms of price, Hangwa should become more available by lowering the price barrier for consumers who are sensitive to price.

• IE interfaces
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• v.16 no.4
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• pp.392-399
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• 2003

ISO 9000 is an efficient quality system for the customer's confidence and satisfaction. Of late years, the revised edition of ISO 9000 quality management system may give lots of positive business values to companies running ISO 9000 system. Despite its tremendous popularity, there is some criticism against the effect and performance of ISO 9000 certification. This research explores the performances and effects of ISO 9000 quality system in small & medium size industrial companies. For this research, 202 companies certified by ISO 9000 standard and 67 companies not certified as contrast group were selected. The related data were collected by web-poll survey. The major analyses are focused on the effect and performance of the ISO 9000 certification, and we established various hypotheses to verify the effect and performance of quality system. Results of statistical analyses show that total performance of quality system is significantly different between certified companies and not certified.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.4
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• pp.15-25
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• 2005

As implied by the terms of IT productivity Paradox, measuring the Information technology contribution to economic performance has been one of the challenging issues to both policy makers and business professionals. As such, diverse attempts with sophisticate analyses have been reported in the literature to analyze the effect of IT contributions. In this paper, we follow Growth Accounting Method to measure the IT contribution effect to manufacturing firm's economic performance in Korea. Various regression methods and statistical analyses are applied with fourteen years of industry Panel data. Using the Cobb-Douglas function, time lag analysis is made to understand IT effect to economic growth. Instead of capturing data from individual firm, industry level data from the National Statistics Bureau is used for IT capital, non-IT capital, and so on. Statistical analysis following the panel unit test and Panel co-integration test was performed to reveal the exact effect of IT contribution to economic performance. Empirical testing results for non-stationary nature of IT investment effect are reported as well as IT contribution to manufacturing industry's economic performance.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.201-210
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• 2020

The study aims to investigate determinants of performance indicator and perceptions of existing and potential customers in accommodation sharing. This study uses data of Airbnb in Busan and Jeju from January 1 to December 31 in 2018, provided by AirDNA. The total number of listed accommodation sharing were 5,109 accommodations in Busan and 11,502 accommodations in Jeju. More than 90 property types of registered accommodation are subcategorized and re-classified in this study. Study 1 examined current usage and effects of factors on performance indicator in tourism destinations by applying Airbnb data. Study 2 investigated effects of perceived factors on satisfaction, intention to use, loyalty, and tourism competitiveness by applying online survey data. This study applies statistical analyses such as factor and regression analyses, ANOVA, t-test, and MANOVA. Results of Study 1 showed that usage and effects of accommodation sharing differ from regulation that is related to sharing types. Effects also differ based on travel destinations. Results of Study 2 showed how customers perceive accommodation sharing differ from pure meaning of sharing. The results of Study 1 and 2 found significant effects of price and service factors on performance indicator and customer satisfaction. The findings of Study 2 showed significant effects on loyalty and tourism competitiveness.