• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.410-415
• /
• 2000

Slip factor is defined as an empirical factor being multiplied to theoretical energy transfer for the estimation of real work input of a centrifugal compressor. Researchers have tried to develop a simple empirical model, for a century, to predict a slip factor. However most these models were developed on the condition of design point assuming inviscid flow. So these models often fail to predict a correct slip factor at off-design condition. In this study, we summarized various slip factor models and compared these models with experimental and numerical data at off-design condition. As a result of this study, Wiesner's and Paeng and Chung's models are applicable for radial impeller, but all the models are not suitable for backswept impeller. Finally, the essential avenues for future study is discussed.

• Steel and Composite Structures
• /
• 제22권3호
• /
• pp.677-690
• /
• 2016

In this paper, the effect of damping ratio on nonlinear dynamic analysis response and dynamic increase factor (DIF) in nonlinear static analysis of structures against column removal are investigated and a modified empirical DIF is presented. To this end, series of low and mid-rise moment frame structures with different span lengths and number of storeys are designed and the effect of damping ratio in DIF is investigated, performing several nonlinear static and dynamic analyses. For each damping ratio, a nonlinear dynamic analysis and a step by step nonlinear static analysis are carried out and the modified empirical DIF formulas are derived. The results of the analysis reveal that DIF is decreased with increasing damping ratio. Finally, an empirical formula is recommended that relates to damping ratio. Therefore, the new modified DIF can be used with nonlinear static analysis instead of nonlinear dynamic analysis to assess the progressive collapse potential of moment frame buildings with different damping ratios.

• 혜화의학회지
• /
• 제22권2호
• /
• pp.143-154
• /
• 2014

Objective : The purpose of this study is to establish a concept called as 'medical service' newly and to develop an reliable and valid scale that measures medical service. Methods : In order to accomplish these objectives, both conceptual study and empirical study were performed. In a conceptual study, 5 core factors(doctor, medical team, medical facilities, medical process, and hospital) and 24 sub factors were extracted with assistant by 7 experts, based on antecedent studies about components of medical service. In an empirical study, data was taken from 244 adults living in Seoul and Daejeon with the conceptually founded medical service scale. Results : Results of empirical study showed reliability and validity of the medical service scale. Internal consistency coefficient showed high score of .97 and, in accordance with the conceptual study, "medical treatment factor", "appearance factor", "personal factor", "trust factor" and "dissatisfaction factor" were extracted from the data as the five main factors. Conclusions : Finally, limitations of this study and directions for further studies are discussed. Acknowledgement : This work was supported by the Daejeon University Research Grant.

• 한국경영과학회지
• /
• 제32권2호
• /
• pp.41-51
• /
• 2007

We categorize quality management practices as two factors ; 'infra factor' and 'process factor.' We confirm the factors' statistical significance with empirical investigation about 167 manufacturing companies in nationwide. Moreover, we find the two factors affect positively on the manufacturing capabilities of differentiation and reliability, and on the performances as improving products and process. We prove these results with empirical method of structural equation model and AMOS program.

• 한국산업정보학회논문지
• /
• 제20권4호
• /
• pp.25-37
• /
• 2015

The early studies indicated that the firm with monopoly power is likely to engage in X-inefficiency such as a managerial slack. The reflection of the X-inefficiency theory has led to the issue that the public sector may be more inefficient than the private sector. In Korea like other many countries the electricity gas water service which can be considered as natural monopoly have been provided mostly by the public sector. In order to provide the empirical evidence to the argument that the public sector may be more inefficient than the private sector this paper estimated the four types of Solow residual which is called the total factor productivity in the electricity gas water service industry with the associated empirical model and compared its productivity with one in the manufacturing industry. The empirical results do not support the argument that the public sector may be more inefficient or less productive than the private sector.

• World Technopolis Review
• /
• 제4권3호
• /
• pp.144-156
• /
• 2015

Globalization and knowledge-based economy have increased the importance of local areas as the units of global competition. Therefore, the meaning of localities has been emphasized as the core value of economic activities. In this context, innovation cluster has been recognised and emphasized as effective policy measure for innovation. Therefore, most countries have been trying to develop innovation clusters with their expectation for a rapid growth of economy. Nevertheless, there have been minimal empirical researches on innovation cluster. Therefore, for suggesting implications that activation factors of innovation cluster are to have an effect on tenant's business activities, this study conducted a literature review for the theories of regional innovation system(RIS) and innovation cluster. As a result, the activation factors of innovation cluster were classified into institutional, physicals, and social factor. The case of Gyeonggi province's innovation cluster policy was examined for an empirical analysis. Data were analyzed using ordered logistic regression. The results were as follows:First, Institutional and Infra factors had a positive influence on firms' business activities in every empirical test, so they were the most important activation factors of innovation cluster. Second, regarding the interactive effects of financial support, the interactive effects between financial support and Infra factor had a positive influence on the firms' business activities, according to the result of the empirical test.

• 한국정보전자통신기술학회논문지
• /
• 제16권5호
• /
• pp.338-346
• /
• 2023

등척성 팔굽 굽힘시 전완길이(florearm length)는 전완에 가해진 힘의 방향이 직각일 때 관절토크 뿐만 아니라 최대근지구력시간(maximum endurance time: MET)을 결정하는 중요한 요소이다. 본 연구의 목표는 전완의 등척성 수축시 MET의 대표적인 두 가지 실증적 모델인 지수모델과 거듭제곱모델에 전완길이를 추가요소로 적용했을 때 미치는 영향을 검토하는 것이다. 30명의 자원자가 실험에 참여하였으며, 요소변수로 사용할 참여자의 상완 및 전완의 둘레 및 길이들과 최대자율수축강도의 백분율(percent of maximum voluntary contraction intensity: %MVC)에 따른 MET를 측정하였다. 실험과정에서 ln(MET)의 다중선형회귀모델에서 유의확률을 산츨한 결과 %MVC와 전완길이가 유의한 독립변수임을 확인하였다 (P<0.05). 또한, 측정 MET와 기존의 두 가지 실증적 모델들 사이의 평균절대편차는 19.4초 였으나 전완길이를 적용한 모델을 이용한 경우 16.2초로 감소하였으며, 상관계수과 급내상관계수는 모두 평균 0.87 이었으나 전완길이를 적용했을 때 평균 0.91로 모두 증가하였다. 실험결과로부터 전완의 길이가 실증적 모델에 유의한 추가 요소임을 확인하였다.

• 한국농공학회지
• /
• 제37권3_4호
• /
• pp.82-89
• /
• 1995

The efforts of formulation have been reviewed and the results of existing laboratory experiments are investigated in order to describe the contracted flow which occurs at the final closure of sea dike construction. The regional characteristics of contracted flow is analyzed by checking the drawdown curve, and Chezy's mean velocity equation is employed to estimate the discharge rate at the closure. Weir-type discharge equations are reviewed, which are derived from Bernoulli equation, and the problems of the equations are discussed. Chezy's mean velocity equation is considered to be widely and generally applicable, and the empirical factor introduced in Chezy's equation is named 'form drag factor' since it is primarily dependent on the form drag caused by the contraction of discharge area. Laboratory experiments were conducted mainly in order to investigate the variation of form drag factor against various parameters, and an empirical equation is developed for the estimation of form drag factor.

• East Asian Economic Review
• /
• 제18권2호
• /
• pp.111-142
• /
• 2014

We examine whether country fundamentals help explain the cross-section of currency excess returns. For this purpose, we consider fundamental variables such as default risk, foreign exchange rate regime, capital control as well as interest rate in the multi-factor model framework. Our empirical results show that fundamental factors explain a large part of the cross-section of currency excess returns. The zero-intercept restriction of the factor model is not rejected for most currencies. They also reveal that our factor model with country fundamentals performs better than a factor model with usual investment-style factors. Our main empirical results are based on 2001-2010 balanced panel data of 19 major currencies. This paper may fill the gap between country fundamentals and practitioners' strategies on currency investment.

• 산업경영시스템학회지
• /
• 제27권4호
• /
• pp.105-109
• /
• 2004

The purpose of this paper is to examine the empirical analysis for charging factors and the evaluation models of internet site. Thus this is to analyze the revenue creation factors affecting the customer satisfaction of tourism information sites in the Internet. Based on the regression model applied to a customer survey, this study shows that among the characteristics of the site, technical factor and community factor have the most significant effect on charging factor and customer satisfaction.