• Agribusiness and Information Management
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• 제5권1호
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• pp.42-54
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• 2013

Information System (IS) Success Model proposed by DeLone and McLean is applied as a successful operation tool of information system, with its basic assumption of symmetric relationship between independent variables and dependent variables of the structural equation modeling. However, because previous studies have proved asymmetry of quality factors' influence structure on dependent variable by applying three-factor analysis, this study examined asymmetry of impact structure of quality factors introduced in IS Success Model on user satisfaction. Also the study applies structure equation modeling (SEM), three-factor analysis and importance and performance analysis (IPA) to develop resource allocation strategy for IS success. The study is able to provide IS practitioners with strategic implications for allocating and managing limited resources more effectively.

• 소성∙가공
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• 제14권4호
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• pp.392-398
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• 2005

The deterioration of dimensional accuracy, caused by springback, is one of problems to always occur In sheet metal forming processes. As the demand for lighter and stronger metals increases, the development of improved forming processes settling the springback problem becomes more important. In this work, asymmetric springback phenomena are investigated, which occur in the shallow-drawing process with the anisotropic sheet metal and axisymmetric tools. The improvement possibility of dimensional accuracies, mainly, flatness, was examined by applying segmented blank holding forces as a method for springback control.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.132-135
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• 2003

Asymmetric rolling, in which the ratio of the rotation rates of the upper and lower rolls was 2, has been used to introduce an intense plastic shear strain for the purpose of grain refinement and developing shear deformation textures through the sheet thickness to improve the strength and plastic strain ratio of AA1050 aluminum alloy sheets. The alloy sheets were rolled at room temperature without lubrication. The textures and microstructures of the sheets were investigated by x-ray diffraction and electron back-scattered diffraction (EBSD) analyses with emphasis on effects of combinations of rot ling directions.

• 한국정밀공학회지
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• 제26권5호
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• pp.64-71
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• 2009

Cylindrical lens core for optical transceiver was designed and machined. With the lens design data, WC asymmetric core surface data were generated for non-revolutional ultra-precision grinding. Grinding process for optimum machining conditions of target surface was studied in terms of surface roughness and form profile. We used experimental results to optimize turbine speed, feed-rate and depth of cut with durable grinding wheel wear. Ground WC cores were measured contact type profilers and verified.

• Journal of Power Electronics
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• 제18권2호
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• pp.418-431
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• 2018

This paper presents a new asymmetrical multilevel inverter with a reduced number of power electronic components. The proposed multilevel inverter is analyzed using two different configurations: i) First Configuration (with a switched diode) and ii) Second Configuration (without a switched diode). The presented topologies are compared with recent multilevel inverter topologies in terms of number of switches, gate driver circuits and blocking voltages. The proposed topologies can be cascaded to generate the maximum number of output voltage levels and they are suitable for high voltage applications. Various power quality issues are addressed for both of the configurations. The proposed 11-level inverter configuration is simulated using MATLAB and it is validated with a laboratory based experimental setup.

• Applied Microscopy
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• 제24권4호
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• pp.32-40
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• 1994

This study was undertaken to study the morphological changes of rat synapses during early postnatal periods. Neonatal rats were grouped by 1st, 2nd, 3rd, 4th and 6th postnatal weeks, and we observed the ultrastructural pattern of the synapses in the external plexiform layer of olfactory bulbs by electron microscopy. The results were as follows; 1. The numbers of synapses, lengths of synaptic thickenings and amounts of synaptic vesicles were markedly increased in the external plexiform layer during four postnatal weeks. 2. There was a tendency of increasing the proportion of the asymmetric synapse and the curved synapses during maturation. From the above results, it is suggested that the size of synapse is increasing during maturation, and at the same time the asymmetric synapses are formed from the symmetric type and the curved synapses are from the plane type.

• 전기학회논문지
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• 제56권2호
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• pp.289-294
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• 2007

This paper describes the effects of rotor eccentricity in squirrel cage induction machines. Asymmetric electro-magnetic force caused by the frictional worn bearing, rotor misalignment and unbalanced rotor etc. generates an asymmetrical operation, vibration and electro-magnetic noise. The need for detection of these rotor eccentricities has pushed the development of monitoring methods with increasing sensitivity and noise immunity. In this paper, we focus on investigating the asymmetrical operation considering of unbalanced magnetic pull in squirrel-cage induction motor with 380 [V], 7.5 [kW], 4P, 1,768 [rpm]. The effects of the non-symmetric rotor and magnetic force are simulated by finite element method (FEM) and tested using search coils for measuring the actual air-gap flux.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.284-287
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• 2001

In the System-integrated modular advanced reactor(SMART), the motor for Control element drive mechanism(CEDM) requires high density power and simple drive mechanism to reduce volume because of restriction by install-space and must satisfy the reactor operating circumstances with high pressure and temperature. To Maximize the characteristics of the TFM, we chose the asymmetric bridge converter as the driving system for TFM. Because two switching devices are connected in series with the stator winding of each phases in the asymmetric bridge converter all the phases are not affected by another phase but controlled independently. Also, this converter has many advantages that the various control methods can be adopted, it is easy to control, and that in case that the switching devices of a phase are damaged, the affects can be minimized.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.51-54
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• 2005

Light Guide Plate (LGP) of LCD-BLU(Back Light Unit) is manufactured by forming optical pattern with $5\~100um$ in diameter on the LGP by means of sand blasting or etching method. However, in order to improve the luminance of LCD-LGP, the design of optical pattern has introduced UV inclined-exposure process in this study. This micro-optical pattern, which has asymmetric elliptical column shaped pattern, can change low viewing-angle to high viewing-angle, as well as it contribute to diffusion of light. As a result, this type of micro-optical pattern can introduce the highly luminance. The PR structure obtained in the stage of lithography has asymmetric elliptical column shape and it is processed into a micro-optical pattern. Optical design with this kind of micro-optical pattern, mold fabrication by electroplating and LGP molding with injection molding are under way.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.265-271
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• 2011

기존의 재래식, 전단, 튜브 스피닝은 모두 축대칭 제품의 형상화된 맨드릴을 사용하여 가공하여 왔다. 이러한 고전적 기법에서 한걸음 더 나아가 비축대칭, 열처리를 동반한 스피닝, 자유 맨드릴 공법이 시도되고 있다. 본 조사에서는 비대칭 스피닝과 열처리 스피닝에 등에 대한 신기술 동향과 자유 맨드릴을 사용하는 스피닝 기술 동향을 조사하였다.