• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1008-1012
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• 1997

This study is on a mathematical model of profile shifted involute gear, and this model is based on Camus's theory. Gear is general mechanical elements that used for power transmission between two shafts that interval is comparatively short. and it delivers bit power as accurate ratio of speed. The profile of Spur gear which is the most basic factor is divided into Trochoidal fillet curve and Involute curve. Involute curve is used a lot of a shape curve of machine parts such as a gear, a scroll compressor and a collar of centrifugal pump. However, It is poor to study the modeling of Trochoidal fillet curve and the three dimensions model shaped mathematical curve. So we draw three dimensions gear have accurate mathematical function using ADS(Automatic Drawing system), VisualLISP. To check accuracy and perfection, we make a program of checking Interference. and use for this study.

• Smart Structures and Systems
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• 제21권4호
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• pp.397-405
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• 2018

In this paper, a novel simple shear deformation theory for buckling analysis of single layer graphene sheet is formulated using the nonlocal differential constitutive relations of Eringen. The present theory involves only three unknown and three governing equation as in the classical plate theory, but it is capable of accurately capturing shear deformation effects, instead of five as in the well-known first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Nonlocal elasticity theory is employed to investigate effects of small scale on buckling of the rectangular nano-plate. The equations of motion of the nonlocal theories are derived and solved via Navier's procedure for all edges simply supported boundary conditions. The results are verified with the known results in the literature. The influences played by Effects of nonlocal parameter, length, thickness of the graphene sheets and shear deformation effect on the critical buckling load are studied. Verification studies show that the proposed theory is not only accurate and simple in solving the buckling nanoplates, but also comparable with the other higher-order shear deformation theories which contain more number of unknowns.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.544-558
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• 2013

This paper proposes a simplified and efficient control scheme for Unified Power Quality Conditioner (UPQC) based on three-level (NPC) inverter capable to mitigate source current harmonics and compensate all voltage disturbances perturbations such us, voltage sags, swells, unbalances and harmonics. The UPQC is designed by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The dc voltage is maintained constant using proportional integral voltage controller. The shunt and series AF are designed using a three-phase three-level (NPC) inverter. The synchronous reference frame (SRF) theory is used to get the reference signals for shunt and the power reactive theory (PQ) for a series APFs. The reference signals for the shunt and series APF are derived from the control algorithm and sensed signals are injected in tow controllers to generate switching signals for series and shunt APFs. The performance of proposed UPQC system is evaluated in terms of power factor correction and mitigation of voltage, current harmonics and all voltage disturbances compensation in three-phase, three-wire power system using MATLAB-Simulink software and SimPowerSystem Toolbox. The simulation results demonstrate that the proposed UPQC system can improve the power quality at the common connection point of the non-linear load.

• The Journal of Asian Finance, Economics and Business
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• 제7권6호
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• pp.399-407
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• 2020

The paper examines social entrepreneurial intention through outcome expectations. The proposed model incorporates outcome expectations from social cognitive career theory and theory of planned behaviors. The study also introduces a scale for outcome expectations in social entrepreneurship, including solving social problems, innovation, family tradition of social involvement, meaning in life, prestige and social recognition, competitive and favorite job and wealth. A survey of 279 students was conducted through face-to-face structured interviews. The confirm factor analysis and technique of structural equation modeling were used to explore relationships among latent constructs. Research results show that the outcomes impact only through three determinants of theory of planned behavior and do not have significant impact to social entrepreneurial intention. It suggests that outcome expectations may be a flexible factor. Individual outcome expectations can shift to motivations when facing favorable conditions such as family support, government support, etc. The findings suggest that the ability to predict social entrepreneurial intention of attitude toward behavior, subjective norms, and perceived behavioral control. The proposed model in this study contributes importantly to the emerging literature on entrepreneurial intention, particularly to social entrepreneurial intention. This study is also the first quantitative study to measure the impact of outcome expectations on social entrepreneurial intention.

• 농촌지도와개발
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• 제22권2호
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• pp.101-116
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• 2015

This study aims to identify the decision-making factors of people who have returned to rural areas for farming and residence according to personal characteristics and regions. The survey was conducted on 420 return farmers of six cities and counties in Gyeongsangbuk-Do from September 1st to October 11th 2013. For data analysis, researchers used 280 answered sheets and utilized two-way ANOVA and multinomial logistic regression analysis. Research results indicate three factors of returning to farm which are pull to rural area, push from city, and policy factor. The highest scores of factor is pull to rural area (2.93), the second one is push from city (2.31), and the lowest score is politic factor (2.18). In addition, these three factors of returning to farm are elucidated by environmental variable, economic variable, and information and opportunity provided by government. In other words, the factor of pull to rural area is related environmental variable and the factor of push from city is affected by economic variable. Lastly, politic factor pertains to information and opportunity provided by government.

• Safety and Health at Work
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• 제12권3호
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• pp.339-345
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• 2021

Background: Some researchers state that they are not yet able to provide a deep understanding of the underlying causes of unsafe behaviors (UBs). Therefore, the present study was conducted to investigate the attitudes and experiences of Iranian workers of UBs. Methods: This present study was conducted in 35 industries using a semistructured interview based on grounded theory. Forty participants were interviewed, including 13 industrial safety and health experts and 27 workers and supervisors. The analysis of the present study consisted of a three-step coding process including open, axial, and selective coding. Results: The results showed that the factors affecting UBs could be classified into three categories: organizational, individual, and socioeconomic factors. Organizational factors were divided into 6 parts: procedure and environmental conditions, communications, monitoring, organizational safety culture, resource allocation, and human resources. Socioeconomic factors had three subcategories: community safety culture, type of organizational ownership, and economic problems. Finally, the individual factors were classified into two categories of personality traits and individual competence. Conclusion: The results showed that organizational factors were the most categorized, and it is estimated that this factor has a more important role in the UBs. Of course, to better understand the close relationship between these factors and find the weight and importance of each factor, it needs to measure it with multicriteria decision systems.

• Journal of Welding and Joining
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• 제3권2호
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• pp.52-63
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• 1985

Fillet welded joints, specially in ship structure, are well known the critical part where stress concentrate or crack initiates and grows. This paper is concerned with the study of the behavior of fatigue crack growth t the root and toe of load carrying cruciform fillet welded joints under three points bending by the determination of stress intensity factor from the J-Integral, using the Finite Element Method. The stress intensity factor was investigated in accordance to the variation of the weld size (H/Tp). weld penetration (a/W) and plate thickness (2a'/Tp). As mixed mode is occurred on account of shearing force under the three points bending, Stern's reciprocal theory is applied to confirm which mode is the major one. The main results may be summarized as follows 1) The calculation formula of the stress intensity factor at the both of root and toe of the joint was obtained to estimate the stress intensity factor in the arbitrary case. 2) The change of stress field around crack tip gives much influence on each other at the roof and toe as H/Tp decreases. 3) Mode I is a major mode under the three points bending.

• Steel and Composite Structures
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• 제18권6호
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• pp.1353-1368
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• 2015

A finite element model is presented for the analysis of composite steel-concrete beams based on a refined high-order theory. The employed theory satisfies all the kinematic and stress continuity conditions at the layer interfaces and considers effects of the transverse normal stress and transverse flexibility. The global displacement components, described by polynomial or combinations of polynomial and exponential expressions, are superposed on local ones chosen based on the layerwise or discrete-layer concepts. The present finite model does not need the incorporating any shear correction factor. Moreover, in the present $C^1$-continuous finite element model, the number of unknowns is independent of the number of layers. The proposed finite element model is validated by comparing the present results with those obtained from the three-dimensional (3D) finite element analysis. In addition to correctly predicting the distribution of all stress components of the composite steel-concrete beams, the proposed finite element model is computationally economic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1247-1249
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• 2003

Despite many advantages, d-q theory was available only for three phase system. But recently, some papers proposed the application methods of d-a theory or similar theories for single phase systems. This paper presents the control method of the utility-connected single-phase inverter using d-q theory. The suggested method gives single-phase system instantaneous controllability and also makes the realization of APF(Active Power Filter) without DFT operation and PFC(Power Factor Controller) possible. This paper deals with utility-connected single phase inverter with PFC function. The controller was verified by simulation tool.

• 한국한의학연구원논문집
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• 제3권1호
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• pp.119-151
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• 1997

Conclusions for the relationship between a conceptional model of stress theory and its examination based on the Oriental medicine; 1. It was considered that a general conception of stress is included into the meaning of Ki in the Oriental medicine. 2. The response-based model to stress could be comparable to a conception of Ki-pathogens interchange In the Onental medicine. 3. The stimulus-based model may be explained as a modern conception of immoderation feeling related with an internal etiological factor, specially injury of seven emotions, among three groups of etiological factors for disease. 4. The feedback conception based on the interaction model could explain the principal of reversible emotion therapy in the nine Ki. 5. In the Oriental medicine, a study to clarify a emotional etiologic factor and its pathophysiologlcal mechanism has been continued for long time before establishment of stress theory.