• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.7
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• pp.666-673
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• 2011

To perform effective integration test of avionics equipments, the importance of a setup for integration test environment has been increasing in recently developed aircraft. Especially, the development of integration test equipment is necessary for minimizing the development period and reliability of integration test. This paper treats the model development for optimal working of integration test after analyzing the characteristics of each MEP equipments for Surion(KUH). Models, whose main role is troubleshooting of equipment and simulation for missing equipments, consists of dynamic, behavior, and ICD models depending on the dynamic characteristics. Software test for both unit level and system level are performed to verify the model reliability. By conducting integration test using SIL, it is confirmed that the developed models are suitable for integration function test of the MEP system.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.103-112
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• 2011

Purpose: of this survey research was to investigate the satisfaction level of clinical training for 300 students in the department of dental technology. Methods: This survey was carried out from 1th of january to 20th of january and analyzed using the Statistical Package for Social Sciences 17.0 for Windows. As for the analysis methods, the study used the frequency analysis, percentage, mean, t-test, analysis of variance, multiple regression analysis. Results: The results of multiple regression analysis between the satisfaction level and the related factors indicated that the satisfaction of major and place of clinical training in the clinical training are the major component in the male students and the satisfaction of major and a school record and clinical training experience are the major component that contribute the satisfaction level in the female students. Conclusion: Regular course of training and pre-employment training also recommends to students in the department of dental technology. Faculty and clinical dental technicians should try in order to improve satisfaction level of clinical training.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.65-69
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• 2010

In this study, we investigated the effects of UBM(Under Bump Metallization) and solder composition on the drop impact reliability of wafer level packaging. Fan-in type WLP chips were prepared with different solder ball composition (Sn3.0Ag0.5Cu, and Sn1.0Ag0.5Cu) and UBM (Cu 10 ${\mu}m$, Cu 5 ${\mu}m$\Ni 3 ${\mu}m$). Drop test was performed up to 200 cycles with 1500G acceleration according to JESD22-B111. Cu\Ni UBM showed better drop performance than Cu UBM, which could be attributed to suppression of IMC formation by Ni diffusion barrier. SAC105 was slightly better than SAC305 in terms of MTTF. Drop failure occurred at board side for Cu UBM and chip side for Cu\Ni UBM, independent of solder composition. Corner and center chip position on the board were found to have the shortest drop lifetime due to stress waves generated from impact.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.02a
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• pp.37-59
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• 2004

In the case of Ni/Au finished pad on the package side, the solder joint of SnAgCu system can bring brittle fracture under impact load such as drop test. Therefore, it's difficult to prevent the brittle fracture of lead-free solder, by controlling Cu content. The failure locus existing on the interface between $(Ni,Cu)_3Sn_4\;and\;(Cu,Ni)_6Sn_5$ IMC layers must be changed to other site in order to avoid brittle fracture due to impact load. It was not found any clear evidence that there were two IMC layers exist. But it was strongly assumed these were two layers which have different Cu-Ni composition. From the above analysis it was assumed that Cu atom in the solder alloy or substrate seemed to affect IMC composition and cause to IMC brittle fracture.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.53-59
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• 2014

The mechanical stability of solder joints in electronic devices with Sn-Ag-Cu is a continuous issue since the material was applied to the industry. Various shock test methods were developed and standardized tests are used in the industry worldwide. Although it is applied for several years, the detailed mechanism of the shock induced failure mechanism is still under investigation. In this study, the effect of external temperature was observed on large Flip-chip BGA components. The weight and size of the large package produced a high strain region near the corner of the component and thus show full fracture at around 200G level shock input. The shock performance at elevated temperature, at $100^{\circ}C$ showed degradation based on board pad designs. The failure mode and potential failure mechanisms are discussed.

• International Journal of Advanced Culture Technology
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• v.7 no.1
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• pp.1-7
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• 2019

The purpose of this study is to investigate and analyze the service satisfaction of users using community service, and to suggest directions for continuous growth and high service of social service providers in the future. This study was conducted on G metropolitan cities. T-test and one-way ANOVA were conducted for the comparison of 476 users of social service users by gender, income level, and age. In addition, multiple regression analysis was conducted to identify factors affecting user satisfaction. The statistical package analyzed was SPSS 21.0. As a result of the study, the application process, the satisfaction of the service period, and the satisfaction of the service provider were statistically significant at the income level. In addition, in the age group satisfaction, the application procedure, the satisfaction of the service period, the satisfaction of the service frequency, and the satisfaction of the workforce were statistically significant.

• Journal of the Korean Home Economics Association
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• v.33 no.4
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• pp.11-23
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• 1995

The purpose of this study is to investigate some influencing factors related to the urban housewives' homemanagement and management behavior on the problems of the environment. Questionaire Survey method was used and the sample was taken from 490 housewives who lives in Seoul and has husband and more than one child. The Research for this study was operated by frequency, mean, percentage, Factor Analysis, t-test, ANOVA, Duncan's multiple range test, and multiple regression analysis through the SAS program package. Based on the findings of this study, housewives' value, degree of exposure to mass communications, housewives' level of education were most influencial variables on Housewives' home management behavior pattern. And Housewives' home management behavior pattern, degree of exposure to mass communications, housewives' age, knowledge of the problems of the environment were most influencial variables on Housewives' management behavior onthe problesm of the environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.345-350
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• 2002

In this study, researchers classifying the artificial flaws in semiconductor packages are performed by pattern recognition technology. For this purposes, image pattern recognition package including the user made software was developed and total procedure including ultrasonic image acquisition, equalization filtration, binary process, edge detection and classifier design is treated by Backpropagation Neural Network. Specially, it is compared with various weights of Backpropagation Neural Network and it is compared with threshold level of edge detection in preprocessing method fur entrance into Multi-Layer Perceptron(Backpropagation Neural network). Also, the pattern recognition techniques is applied to the classification problem of defects in semiconductor packages as normal, crack, delamination. According to this results, it is possible to acquire the recognition rate of 100% for Backpropagation Neural Network.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.69-73
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• 2011

Questionnaire survey has been made for the above study. First, 65 question sheets have been distributed to railway operators and 55 sheets of them have been collected from them. SPSS 12.0 program package has been used to analyze those sheets concerning age, experience, school, background as a frequency analysis and t-test has been made to find out recognition level difference of a cheer response, depending on the operator's experience. T-verification has been made for two groups such as less than 10 years, and 10 years or more experience. Result from correlation analysis showed that there was no difference due to operators' experience.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.3_4
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• pp.373-383
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• 2003

The purpose of this study was to investigate the effects of personal characteristics on job stressors, job stress symptoms, and job performance of workers in fashion and textile industries. Personal characteristics includes gender, marital status, educational level, age, type of industry, type of occupation, job position and work period. The data were obtained from questionnaire completed by 529 workers who were employed by textile or clothing manufacturers located in Seoul, Daegu, or Gyeongsang-do province. The SPSS package was used for data analysis which includes frequency, factor analysis, t-test, ANOVA and Scheffe's test. The results indicated that all personal characteristics had significant effects on job stressors, job stress symptoms, and job performance. Age and job position among personal characteristics showed to be the most important variables which influenced job stressor, job stress symptoms, and job performance.