• 소성∙가공
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• 제15권8호
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• pp.544-549
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• 2006

In this work, we have employed the strain gradient plasticity theory to investigate the effect of material size on the deformation behavior in metal forming process. Flow stress is expressed in terms of strain, strain gradient (spatial derivative of strain) and intrinsic material length. The least square method coupled with strain gradient plasticity was used to calculate the components of strain gradient at each element of material. For demonstrating the size effect, the proposed approach has been applied to plane compression process and micro rolling process. Results show when the characteristic length of the material comes to the intrinsic material length, the effect of strain gradient is noteworthy. For the microcompression, the additional work hardening at higher strain gradient regions results in uniform distribution of strain. In the case of micro-rolling, the strain gradient is remarkable at the exit section where the actual reduction of the rolling finishes and subsequently strong work hardening take places at the section. This results in a considerable increase in rolling force. Rolling force with the strain gradient plasticity considered in analysis increases by 20% compared to that with conventional plasticity theory.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.621-633
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• 2006

To reflect the size effect of material $(1\sim15{\mu}m)$ during plastic deformation of polycrystalline copper, a constitutive equation which includes the strain gradient plasticity theory and intrinsic material length model is coupled with the finite element analysis and applied to plane strain deformation problem. The method of least square has been used to calculate the strain gradient at each element during deformation and the effect of distributed force on the strain gradient is investigated as well. It shows when material size is less than the intrinsic material length $(1.54{\mu}m)$, its deformation behavior is quite different compared with that computed from the conventional plasticity. The generation of strain gradient is greatly suppressed, but it appears again as the material size increases. Results also reveal that the strain gradient leads to deformation hardening. The distributed force plays a role to amplify the strain gradient distribution.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1477-1489
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• 2008

This article deals with the problem of testing whether the effect size in paired study exists. We propose Bayesian hypothesis testing procedures for the effect size in paired study under the noninformative prior. The noninformative prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we propose the objective Bayesian hypothesis testing procedures based on the fractional Bayes factor and the intrinsic Bayes factor under the reference prior. Simulation study and a real data example are provided.

• 한국기계가공학회지
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• 제17권6호
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• pp.1-6
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• 2018

Recently nano meter size pattern (sub-micro scale) can be machined mechanically using a diamond tool. Many studies have found a 'size effect' which referred to a specific cutting energy increase with the decrease in the uncut chip thickness at micro scale machining. A new analysis method was suggested in order to observe 'size effect' in nano scale machining and to verify the cause of the 'size effect' in this study. The diamond tool was indented to a vertical depth of 1,000nm depth in order to simplify the stress state and the normal force was measured continuously. The tip rounding was measured quantitatively by AFM. Based on the measurements and theoretical analysis, it was verified that the main cause of the 'size effect' in nano scale machining is geometrically necessary dislocations, one of the intrinsic material characteristics. st before tool failure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.129-130
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• 2010

• 보건행정학회지
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• 제8권1호
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• pp.52-96
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• 1998

To find causal factors and improvement plans of organizational commitment of public servants in urban health centers, a hypothetical causal model, which included 2 endogenous variables(organizational commitment & organizational satisfaction) and 15 exogenous variables, was constructed. Exogenous variables consisted of individual factors (sex, age, education, job-grade, and annual salary), psychological variables(pride for organization, extrinsic motivation, intrinsic motivation and support of supervisor) ad structural variables(formalization, centralization, communication, job-conflict, job-decision, and workload). In the hypothetical causal model, organizational commitment was supposed to be effect variable, and organizational satisfaction was presumed to be intervening variable to mediate between organizational commitment and exogenous variables. For data collection, cross-sectional self-administered questionnaire survey was conducted to 1,295 public servants from 32 urban health centers nationwide. The survey responses were from 934, 72.1% of subjects. But 756 responses(58.4%) were analyzed because of excluding ones with missing values. The hypothetical causal model was fitted by covariance structural analysis with maximum likelihood method. Main results were as follows: (1) The fitted causal model accounted for 33 and 55 percent of total variance of organizational commitment and organizational satisfaction of public servants, respectively. (2) In order of effect size, pride for organization, supervisor support, communication, extrinsic motivation and centralization had an indirect effect effect on organizational commitment through organizational satisfaction. However, the effect of centralization was negative. (3) Pride for organiztion, intrinsic motivation, organizational satisfaction, job-conflict, supervisor support, communication, age, centralization, annual salar and extrinsic motivation had indirect or direct effects on organizational commitment in order of effect size. Among them, effects of job-conflict and centraldization were negative. In conclusion, these results suggested that organizational commitment of public servants in urban health centers could be enhanced by pride for organization, intrinsic and extrinsic motivations, prevention of job-conflict and excess centralization, supervisor support and active communication. Especially, pride for organization and intrinsic motivation were expected to play the most important role.

• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.201-207
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• 2002

In this paper, we haute proposed a novel trench electrode Base Resistance Thyristor(BRT) and trench electrode BRT with a intrinsic region. New power BRTs have shown superior electrical characteristics including the snab-back effect and the forward blocking voltage more than the conventional BRT. Especially, the trench electrode BRT with the intrinsic region has obtained high blocking voltage of 1600V. The blocking voltage of conventional BRT is about 400V at the same size. Because the breakdown mechanism of the BRT is the avalanch breakdown by impact ionization, the trench electrode BRT with intrinsic region has suppressed impact ionization, effectively. If we use this principle, we can develop a super high voltage power device and it applies to another power device including IGBT, EST and etc.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.243-246
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• 2001

In this paper, we have proposed a novel trench electrode Base Resistance Thyristor(BRT) and trench electrode BRT with a intrinsic region. A new power BRTs have shown superior electrical characteristics including snab-back effect and forward blocking voltage more than the conventional BRT. Especially, the trench electrode BRT with intrinsic region has obtained high blocking voltage of 1600V. The blocking voltage of conventional BRT is about 400V at the same size. Because the breakdown mechanism of BRT is avalanch breakdown by impact ionization, the trench electrode BRT with intrinsic region has suppressed impact ionization, effectively. If we use this principle, we can develope super high voltage power devices and applicate to another power devices including IGBT, EST and etc.

• 한국조리학회지
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• 제23권3호
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• pp.63-76
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• 2017

The study intended to investigate the relationship between transformational leadership and creativity of cooks with transformational leadership as antecedent variable. Transformational leadership has been assessed positively in variable studies as a leadership to improve employee's creativity. The authors also tried to explore structural relationships among transformational leadership, intrinsic motivation, and creativity by identifying the meditating role of intrinsic motivation in the relationship between transformational leadership and creativity of cooks. The study subject was CJ FOODVILLE, which is a representative company with its size, sales, and recognition as a domestic restaurant business. A survey was conducted with employees who were working as a cook in restaurants operated by CJ FOODVILLE in metropolitan areas. The results of the study showed that charisma and intellectual stimulation of transformational leadership positively influenced intrinsic motivation, but inspirational motivation and individualized consideration did not significantly influence intrinsic motivation. In addition, the four elements of transformational leadership did not significantly affect creativity. The findings of the study show that intrinsic motivation played a role as a mediation among charisma, intellectual stimulation, and creativity of transformational leadership. Therefore, the findings of the study suggested intrinsic motivation as an important factor affecting creativity of cooks.

• 한국직업건강간호학회지
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• 제29권3호
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• pp.208-218
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• 2020

Purpose: Nurses' job satisfaction corresponds with personal intrinsic value, and is the strongest predicting turnover and job retention intention. This study identified the effectiveness of job satisfaction interventions related to reinforcing intrinsic motivation (JSI-RIM) for hospital nurses. Methods: This study used four core non-Korean databases (Cochrane Library, CHINHL, EMBASE, PubMed), and five Korean databases to search for RCT and NRCT articles published in English and Korean from inception to June 2019. Meta-analysis was performed using the RevMan 5.3.5 program. Results: Thirteen studies featuring 645 hospital nurses were selected for final analysis. A significant large effect was noted on self-efficacy. The effect size on perceived stress and job satisfaction were moderate; however, the effect on resilience outcomes was not significant. Conclusion: This study generated scientific evidence that would facilitate efficient job adaptation for nurses. Additionally, intrinsic factors, including job identity and meaning of work, need to be included in JSI-RIM.