• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.303-309
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• 1995

Many measures to detect multicollinearity in linear regression have been proposed in statistics and numerical analysis literature. Among them, condition number and variance inflation factor(VIF) are most popular. In this study, we give new interpretations of condition number and VIF in linear regression, using geometry on the explanatory space. In the same line, we derive natural measures of condition number and VIF for logistic regression. These computer intensive measures can be easily extended to evaluate multicollinearity in generalized linear models.

• Fisheries and Aquatic Sciences
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• 제21권3호
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• pp.12.1-12.15
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• 2018

A preliminary investigation of length-weight relationship, condition factor and reproductive ecology of African pike fish, Hepsetus odoe, was conducted between June to August 2010 in Lake Eleiyele. A total of 90 samples of the fish species were caught by fishermen using gill nets. The results obtained showed that fish species had isometric growth pattern (contrary to negative allometry expected) with the growth exponent, b value of 2.64, that is not statistically different from 3 and with high statistical power of 0.866 when tested. The mean condition factor, K, was found to be 2.6, indicating that the fish species were in good condition in the study area. For reproductive biology, mean fecundity and gonadosomatic index were found to be 1349 eggs and 3.53% respectively. This study was necessary to fill the knowledge gap and provide information for management and conservation of the investigated species in the lake system. This study recommended that further research needs to be conducted because the sampling was carried out in the rainy season period and within a quarter of a year.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1459-1466
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• 2001

A slip factor is defined as an empirical factor, which should be multiplied to theoretical energy transfer to estimate real work input of a centrifugal compressor. During the last century, researchers have tried to develop simple empirical models to predict the slip factor. However most of these models have been developed based only on design point data. Furthermore flow is assumed inviscid. As a result, these models often fail to predict the correct slip factor at off-design condition. In this study, various models for the slip factor were analysed and compared with experimental and numerical data at off-design conditions. As a result of this study, Wiesner's and Paeng and Chung's models are shown to be applicable for radial impeller, but all the models are found to be inappropriate for backswept impellers.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.124-132
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• 2010

To predict and analyze the rolling stock's fire growth is considered not only important factor in estimating hazard analysis of rolling stock, but also a primary factor in aspect of a rail load facility. Because it's could be regarded as a ignition source in risk assesment for the facility i.e. tunnel and station. However, currently, standardized method to predict and analyze the fire growth has not been completed yet. it is due to the fact that fire growth is not only depended on thermal property of interior materials, but also is affected dominantly by various factors such as ignition source (characterized by location, duration, and intensity), train running condition and in/exterior ventilation condition. Especially, ventilation condition is one of the most effective factor to affect fire growth in compartment space as noticed by under-ventilation fire condition. In this study, the effect of each ventilation condition on fire growth and load were examined through the numerical method through FDS (Fire Dynamics Simulator).

• 대한산업공학회지
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• 제4권2호
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• pp.49-58
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• 1978

The purpose of this study was to analyze the actual condition of curriculum composition by factor analysis, then to find out the peculiarity of each factor through factor loading. The method adopted here is to classify and arrange the curricula in accordance with the similarity of each subject, to put it into computer, and to get 16 factors whose eigenvalues are at least 1.00. Consequentely, before the orthogonal rotation 67% of the curricula which have the given factors and maximum factor loading were distributed from factor 1 to factor 4, and after orthogonal rotation 45% of the curricula were distribued.

• 품질경영학회지
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• 제42권1호
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• pp.63-70
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• 2014

Purpose: This article introduces a case study of using Taguchi Method to improve lecture satisfaction. Developed by Taguchi Genichi, this method has its strength in finding the control factor that is robust against noise factor. Finding the condition for such control factor has an effect of reducing the dispersion of the Lecture satisfaction. Methods: There are various factors in university classrooms. The factors which influenced the Lecture Satisfaction are analyzed by control factors and noise factors, control factors which is controllable are lecture completeness and thoroughly test the degree of supervision and noise factors which is not controllable is degree of physical and psychological Lecturer tired, then the experiment is conducted as guided by Taguchi's experimental design, one semester are experimented by eight professor with 2 classes, after discussion of the results the optimal lecture condition is suggested. Results: To improve Lecture Satisfaction under noise factor of physical and psychological Lecturer tired, optimal condition are that lecture completeness have scenario note during lecture and thoroughly test the degree of supervision have two proctors during test. Conclusion: In this paper, we have succession case by applying Taguchi methods in Lecture Satisfaction. We can apply to improve service by applying the Taguchi methods. In the future we hope to have many succession cases.

• 동력기계공학회지
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• 제16권3호
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• pp.44-50
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• 2012

The reliability qualification test is essential in order to ensure the life time of the product under the normal operation conditions when a new product is developed. The reliability qualification test period has an important impact on the development time of new product. Therefore, some researches to reduce the test time of reliability qualification test have been actively studied. Generally, accelerated life test is well known as one method that can save the test time of the reliability qualification test. This test is conducted under the higher stress condition than normal condition. So we need to investigate what factor affects to the higher stress condition. This paper shows the relationship between the acceleration factor and reliability qualification test period. Especially, we focused on the method to obtain effective acceleration factors under the high temperature condition. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• Geomechanics and Engineering
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• 제37권2호
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• pp.179-187
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• 2024

In this paper, a unified time-dependent constitutive model of Darcy flow and non-Darcy flow is proposed. The influencing factors of flow velocity are discussed, which demonstrates that permeability coefficient is the most significant factor. Based on this, the dynamic evolution characteristics of water inrush during tunneling through fault fracture zone is analyzed under the constant permeability coefficient condition (CPCC). It indicates that the curves of flow velocity and hydrostatic pressure can be divided into typical three stages: approximate high-velocity zone inside the fault fracture zone, velocity-rising zone near the tunnel excavation face and attenuation-low velocity zone in the tunnel. Furthermore, given the variation of permeability coefficient of the fault fracture zone with depth and time, the dynamic evolution of water flow in the fault fracture zone under the variable permeability coefficient condition (VPCC) is also studied. The results show that the time-related factor (α) affects the dynamic evolution distribution of flow velocity with time, the depth-related factor (A) is the key factor to the dynamic evolution of hydrostatic pressure.

• 생태와환경
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• 제40권3호
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• pp.412-418
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• 2007

2005년 4월부터 10월까지 횡성호를 중심으로 상 하부 및 호내지역에 분포하는 피라미 개체군의 동태를 알아보았다. 피라미는 횡성호에서 우점종으로 나타났으며 본 종의 생태학적 특성을 파악하기 위해 댐 상류하천과 호내 그리고 댐 하류지역의 하천에서 채집된 피라미를 지역별로 구분하여 전장과 체중과의 관계, 길이와 비대지수(K와 $K_n$)와의 관계를 각각 비교하였다. 전장-체중의 관계에 의해 관계식을 추정한 결과 $Log(T_W)=-2.26+3.18Log(T_L)$로 나타났다. 회귀계수 b값은 호내지역에서 3.35로 높았고, 상류하천과 댐 하부지역에서 각각 3.09와 3.15의 간을 나타내 유수역인 하천보다 정수역인 호수에서 채집된 피라미가 더 양호한 성장도를 나타냈다 비대지수에 의한 개체군의 비만기울기 또한 양의 상관성을 보였으며 호수에서 기울기 값이 더 큰 것으로 나타났다. 이러한 결과는 횡성호에 분포하는 피라미 개체군이 양호하거나 안정되었음을 반영하고 있다. 호수는 피라미 개체군에 더 좋은 조건을 제공하고 있는 것으로 보인다.

• 패션비즈니스
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• 제17권5호
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• pp.138-150
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• 2013

This paper is purposed to study on the Influence of Working Condition and Job Satisfaction on the change of occupation of Cosmetologist(Hair & Skin Care) to reduce cosmetologist change of occupation. The research methods are surveying with 250 persons & doing statistics analysis such as frequency, factor, regression analysis, using SPSS V.14. The results are as belows; 1. working conditions are reduced by two factors (1) welfare working condition, (2) basic working condition, and job satisfactions are reduced by one factor job satisfaction. 2. There is a relationship demographic characteristics, such as years, income/month, number of colleague in working area, working time/day, day off/month, with change of occupation. 3. There is a relationship working condition with change of occupation. 4. There is a relationship job satisfaction with change of occupation.