• Title/Summary/Keyword: technical influences

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Evaluation of Pull Strengths and Fracture Modes of Solder Joino by Modified Ball Pull Testing with Protrusion Jaw (Protrusion Jaw가 적용된 볼 당김시험을 이용한 솔더 접합부의 강도와 파괴 메커니즘 분석에 관한 연구)

  • Kim Hyoung-Il;Han Sung-Won;Kim Jong-Min;Choi Myung-Ki;Shin Young-Eul
    • Journal of Welding and Joining
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    • v.23 no.4
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    • pp.34-40
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    • 2005
  • There have been numerous approaches to examine the bonding strengths of solder joints. However, despite the technical and practical limitations, the precedent test methods such as the ball shear and ball pull tests are being used in industrial applications. In this study, the optimum jaw pressure with the modified protrusion jaw was introduced in order to obtain higher successful rate f3r ball pull testing. Furthermore, the pull strengths and fracture modes of Sn-8Zn-3Bi, Sn-4Ag-0.7Cu, and Sn-37Pb eutectic solder after isothermal aging tests ($100^{\circ}C,\;150^{\circ}C$), were evaluated with the protrusion jaw. The pull strength-displacement hysteresis curves and fracture surfaces were carefully investigated to evaluate the correlation between the pull strengths and the fracture modes of each solder. In conclusion, it is verified that Au-Zn IMCs (Intermetallic Compounds) have a detrimental effect on the pull strengths and changed fracture modes of Sn-8Zn-3Bi solder. Meanwhile, the microstructure transformation influences the degradation of pull strengths of Sn-4Ag-0.7Cu and Sn-37Pb solders.

The Kinematic Analysis of the Rybalko Motion on the Horizontal Bar (철봉 리발코(Rybalko) 동작의 운동학적 분석)

  • Lee, Byoung-Won
    • Korean Journal of Applied Biomechanics
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    • v.16 no.1
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    • pp.109-117
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    • 2006
  • The purpose of this study was done in order to investigate the Kinematical variables of the Rybalko motion on the Horizontal bar using the 3-dimensional cinematographic method. For this study, three excellent athletes take part in a 2003 Daegue universid game were chosen. The subject,s Rybalko motion was filmed with S-VHS camera at the speed of 60 fields per second and digitized the each fields. And the Kwon3D 3.1 version program was employed to obtain 3-dimensional data. As a result of this study. 1. A total time spent for performing Rybalko skill was Mean $2.52{\pm}0.13sec$. From starting down swing to releasing right hand the Mean $0.84{\pm}0.24sec$ was taken. 2. In the event 3 of Rybalko motion, that is, the moment which the right-hand is released on the bar, the center of mass must is employed at the position above the horizontal line of bar. In this research, the average vertical displacement(z axe) of center of mass shows $47.87{\pm}3.14cm$. 3. In the event 5, that is, the moment which the right-hand is catched again on the bar, the center of mass is employed at the position before the vertical line of bar. In this research, the average horizontal displacement(z axe) of center of mass shows $47.87{\pm}3.14cm$. 4. It has been seen that, at the moment of release of right-hand, lateral variation of center of mass is 13.395cm, vertical variation of center of mass is 7.41cm Thus, it is concluded that lateral variation of center of mass should be reduced for high grade to be acquired. 5. It has been founded that high speed of down swing influences speed of up swing, and that, in the motion of twist, the horizontal speed is little changed.

Using IGA and trimming approaches for vibrational analysis of L-shape graphene sheets via nonlocal elasticity theory

  • Tahouneh, Vahid;Naei, Mohammad Hasan;Mashhadi, Mahmoud Mosavi
    • Steel and Composite Structures
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    • v.33 no.5
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    • pp.717-727
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    • 2019
  • This paper is motivated by the lack of studies in the technical literature concerning to vibration analysis of a single-layered graphene sheet (SLGS) with corner cutout based on the nonlocal elasticity model framework of classical Kirchhoff thin plate. An isogeometric analysis (IGA) based upon non-uniform rational B-spline (NURBS) is employed for approximation of the L-shape SLGS deflection field. Trimming technique is employed to create the cutout in geometry of L-shape plate. The L-shape plate is assumed to be Free (F) in the straight edges of cutout while any arbitrary boundary conditions are applied to the other four straight edges including Simply supported (S), Clamped (C) and Free (F). The Numerical studies are carried out to express the influences of the nonlocal parameter, cutout dimensions, boundary conditions and mode numbers on the variations of the natural frequencies of SLGS. It is precisely shown that these parameters have considerable effects on the free vibration behavior of the system. In addition, numerical results are validated and compared with those achieved using other analysis, where an excellent agreement is found. The effectiveness and the accuracy of the present IGA approach have been demonstrated and it is shown that the IGA is efficient, robust and accurate in terms of nanoplate problems. This study serves as a benchmark for assessing the validity of numerical methods used to analyze the single-layered graphene sheet with corner cutout.

HACCP Performance of Employees in School Foodservice Operations and the Related Variables

  • Kim, Mi-Kyeong;Park, Jyung-Rewng;Cha, Myeong-Hwa
    • Preventive Nutrition and Food Science
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    • v.10 no.4
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    • pp.357-363
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    • 2005
  • The purpose of this study was to assess current food-handling practices of employees in school food service settings, as well as their knowledge levels, and identify relationships between knowledge, practices, and influencing variables. The survey was conducted for dietitians and employees in the school foodservice industry in Gyeongsangbuk-do province. A total of 270 and 570 questionnaires for dietitians and employees, respectively, were distributed by mail. Response rates were $62\%$ (N=171) and $66\%$ (N=376) from dietitians and employees, respectively. Data was analyzed using SPSS Windows (version 10.0). Descriptive statistics were used to summarize data. Pearson correlations were applied to test for relationships between knowledge and practice of HACCP principles. Stepwise regression analysis was performed to examine the influence of knowledge, current education guidelines, demographic information (working experience, academic background, and certification for food and cooking), and school characteristics (food production system, service style, and number of meals). School foodservice employees were found to have a significant amount of food safety knowledge ($67.5\pm1.8$ out of 100 possible points). Proper food handling practices were not always being followed in many schools. The relationship between their knowledge, current HACCP education training, and food handling practices was not significant. These results suggested the present situation of HACCP trainings performed by dietitians were inadequate for many school foodservice operations. The number of meals in school was an independent predictor of the employees' food-handling practices. These results suggest that an effective education program should integrate endeavors that take account of social and environmental influences on food safety to support the improvement of food-handling practices and the implementation of a HACCP program. Furthermore, dietitians should continue to provide consulting, training, and technical assistance to schools on HACCP implementation.

The Analysis of Correlation between Management Performance and Governmental Support Policy for SMB (정부의 중소기업 지원정책과 기업성과의 상관성 분석)

  • Oh, Sang-Young;Hong, Hyun-Gi;Chun, Je-Ran
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.7
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    • pp.1696-1701
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    • 2009
  • In this paper we analyzed the management performance as the result of the korean government's support policy for the small and medium sized business (SMB). The governmental support policy was carried out for the companies classified in 3 criterion. The first is the upbringing of dynamic SMB group, which are driven by creativity and innovation. The second is the enforcement of technology-innovation and cooperation for SMB. The last is the establishment of the growth basis for SMB like funds, human resources and distribution channels. After categorization of above 3 classes, the affect of support policy on the management performance is analyzed, in terms of 3 aspects, management performance, technical performance and policy satisfaction. This study shows that the governmental support policy has the remarkable effects on the financial support sector of SMB. The 5 major sectors, 1) the upbinging of venture-innobiz innovation company, 2) rearing funds of knowledge-based service company, 3) R&D support, 4) support of management stability fund, 5) expansion of distribution channel to the public sector, are designed from 24 variables. The 3 sectors of these 5 are have the main influences from governmental support policy.

Traditional Foods: Historical Perspectives and Future Prospects (문화와 과학의 융합적 관점에서 본 전통음식의 역사 및 미래)

  • Kim, Hee Sup
    • Journal of the Korean Society of Food Culture
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    • v.30 no.1
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    • pp.1-7
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    • 2015
  • Traditional cuisine reflects cooking traditions shaped by political, economic, social, cultural, and environmental conditions characterized by authenticity and uniqueness. Traditional food is not only a part of our cultural heritage but also a knowledge resource. Application of food science and technology in Korean traditional foods was reviewed from six points of view, including food preservation, fermentation, changes in food materials, utilization of food functionality, and packaging and development of cooking appliances. Books from disparate times were chosen in order to cover a wide range of materials from the past to the present. Food preservation and fermentation techniques were applied to various food materials. Combination of science and skills contributes to the accessibility of diverse food materials and better quality foods. Koreans use assorted and resilient plants, which have an abundance of functional substances such as food materials. Among cooking appliances, microwave oven and refrigerator are the most innovative products with huge influences on food eating patterns as well as lifestyle. Packaging effectively reduces post-harvest preservation losses, and better packaging has technical improvements for storage and distribution. Kimchi was chosen as an example in order to study technology from the past to the present. Availability of Kimchi cabbage, enrichment of functional ingredients, identification of useful microbial species, standardization of recipe for commercialization, prevention of texture softening, introduction of salted Kimchi cabbage and Kimchi refrigerators, and packaging were reviewed. The future of traditional foods in the market will be competitive. First, traditional foods market should be maintained to protect the diversity of food materials. Secondly, tailored foods for individuals should be considered using foods with functional properties. Information on health benefits would provide insights into health and traditional food products. Third, speedy transfer of new technology to the traditional food industry is needed to ensure food quality production and new opportunities in the market. Fourth, safety of traditional foods should be ensured without sacrificing the essential characteristics of culturally important foods. Improvement of logistics, distribution, and facility should be carried out. As demand for convenience foods increases, traditional foods should be developed into products.

The effect analysis where beauty care service's quality of perception influences to a value of perception

  • Kim, Sung-Nam;Jung, Hyun-Jin
    • Journal of Fashion Business
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    • v.9 no.6
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    • pp.39-55
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    • 2005
  • This study examines closely the relationship between beauty art service quality and value. And satisfaction and purchase action that they do perceive to customers who have beauty art service company's service use experience. Moreover, this study was achieved purposely to present service raising plan of good quality to beauty art company managers and business employees. First, to investigate the concept of beauty art service quality and special quality was with doctrines that have been presented through a virtue aspect to achieve this study. Moreover, the wave and beauty art service, human service relativity is a let down unlike manufacture enterprise. Further more, beauty art service by complex composition of existence and nonexistence style is sold, and it could be known by having personality consumed at the same time production. The concept of quality about beauty art service and quality that became perceived through virtue study of concept and measurement about value. Therefor, value was deduced, and could deduce measurement, the linear measure that is applied to measure this. Large majority virtue study found is measuring quality of service to 22 articles on PZB's theory, and this study corrects measurement, the linear measure that is applied in Morritt's study that is based in PZB matrix and supplements and attempted measurement to 22 items. The result measurement dimension is consisted of functional quality, technological quality, physical quality dimension. To measure this through virtue study about value that become perceive, could confirm that all expense and beauty art companies which the customer is paid, connect with offering general quality of service. Therefor, through measurement, 2 dimension was deduced by monetary value and the non-monetary value.

Assessment of porosity influence on dynamic characteristics of smart heterogeneous magneto-electro-elastic plates

  • Ebrahimi, Farzad;Jafari, Ali;Mahesh, Vinyas
    • Structural Engineering and Mechanics
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    • v.72 no.1
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    • pp.113-129
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    • 2019
  • A four-variable shear deformation refined plate theory has been proposed for dynamic characteristics of smart plates made of porous magneto-electro-elastic functionally graded (MEE-FG) materials with various boundary conditions by using an analytical method. Magneto-electro-elastic properties of FGM plate are supposed to vary through the thickness direction and are estimated through the modified power-law rule in which the porosities with even and uneven type are approximated. Pores possibly occur inside functionally graded materials (FGMs) due the result of technical problems that lead to creation of micro-voids in these materials. The variation of pores along the thickness direction influences the mechanical properties. The governing differential equations and boundary conditions of embedded porous FGM plate under magneto-electrical field are derived through Hamilton's principle based on a four-variable tangential-exponential refined theory which avoids the use of shear correction factors. An analytical solution procedure is used to achieve the natural frequencies of embedded porous FG plate supposed to magneto-electrical field with various boundary condition. A parametric study is led to carry out the effects of material graduation exponent, coefficient of porosity, magnetic potential, electric voltage, elastic foundation parameters, various boundary conditions and plate side-to-thickness ratio on natural frequencies of the porous MEE-FG plate. It is concluded that these parameters play significant roles on the dynamic behavior of porous MEE-FG plates. Presented numerical results can serve as benchmarks for future analyses of MEE-FG plates with porosity phases.

The effect of information seeking style and news literacy of card news users on recommendation intention: Focused on Technology Acceptance Model (TAM) (카드뉴스 이용자의 정보추구성향과 뉴스 리터러시가 추천의도에 미치는 영향: 기술수용모델(TAM) 모델을 중심으로)

  • Choi, Myung-Il
    • Journal of the Korea Convergence Society
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    • v.10 no.1
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    • pp.141-148
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    • 2019
  • In this study, the Technology Acceptance Model (TAM) was applied to explore the process of using card news. Card news users are found to be active in searching and selecting appropriate news for themselves, information seeking style and news literacy were established as antecedent variables that can influence card news usage. A survey of 400 university students with experience of using card news was conducted. For statistical analysis, SEM was conducted. The analysis showed that information seeking style significantly affects perceived ease of use (PEU) and that news literacy influences neither PEU nor PU. PEU was found to have a significant effect on PU, and both PEU and PU had a significant effect on recommendation intention.

A study on the enhanced filtering method of the deduplication for bulk harvest of web records (대규모 웹 기록물의 원격수집을 위한 콘텐츠 중복 필터링 개선 연구)

  • Lee, Yeon-Soo;Nam, Sung-un;Yoon, Dai-hyun
    • The Korean Journal of Archival Studies
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    • no.35
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    • pp.133-160
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    • 2013
  • As the network and electronic devices have been developed rapidly, the influences the web exerts on our daily lives have been increasing. Information created on the web has been playing more and more essential role as the important records which reflect each era. So there is a strong demand to archive information on the web by a standardized method. One of the methods is the snapshot strategy, which is crawling the web contents periodically using automatic software. But there are two problems in this strategy. First, it can harvest the same and duplicate contents and it is also possible that meaningless and useless contents can be crawled due to complex IT skills implemented on the web. In this paper, we will categorize the problems which can emerge when crawling web contents using snapshot strategy and present the possible solutions to settle the problems through the technical aspects by crawling the web contents in the public institutions.