• Title/Summary/Keyword: inverse regression

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Prediction of the Failure Stress of Tofu Texture Using a Delay Time of Ultrasonic Wave (초음파의 지연 시간을 이용한 두부 조직의 물성변화 예측에 관한 연구)

  • Kim, Hak-Jung;Hahm, Young-Tae;Kim, Byung-Yong
    • Applied Biological Chemistry
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    • v.38 no.4
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    • pp.325-329
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    • 1995
  • Changes in the physical properties of soybean curd upon the processing conditions such as coagulant concentration, heating temperature and molding pressure were determined by using a failure stress and residual delay time of ultrasonic wave(5 MHz). Maximum failure stress of Tofu was obtained at the 0.3% $CaCl_2$ coagulant concentration, $95^{\circ}C$ heating temperature and greater molding pressure, respectively, whereas the delay time is inverse proportion to the failure stress value. The results of the multiple regression analysis with factorial design showed that the model equation consisted with delay time and processing conditions gave the good prediction of the Tofu failure stress.

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A Proposed Method for Estimating Demand function of Cournot Model in Electricity Market (전력시장에서의 쿠르노 수요함수 추정)

  • Kang, Dong-Joo;Hur, Jin;Oh, Tae-Kyoo;Chung, Koo-Hyung;Kim, Bal-Ho H.
    • Proceedings of the KIEE Conference
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    • 2005.11b
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    • pp.168-170
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    • 2005
  • At present Cournot model is one of the most commonly used theories to analyze the gaming situation in oligopoly market. But there exist several problems to apply this model to electricity market. The representative one is to obtain the inverse demand curve able to be induced from the relationship between market price and demand response. In Cournot model, each player offers their generation quantity to accomplish maximum profit, which is accomplished by reducing their quantity compared with available total capacity. As stated above, to obtain the probable Cournot equilibrium to reflect real market situation, we have to induce the correct demand function first of all. Usually the correlation between price and demand appears on the long-term basis through the statistical data analysis (for example, regression analysis) or by investigating consumer utility functions of several consumer groups classified as residential, industrial, and commercial. However, the elasticity has a tendency to change continuously according to the total market demand size or the level of market price. Therefore it should be updated as trading period passes by. In this paper we propose a method for inducing and updating this price elasticity of demand function for more realistic market equilibrium

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Practice of causal inference with the propensity of being zero or one: assessing the effect of arbitrary cutoffs of propensity scores

  • Kang, Joseph;Chan, Wendy;Kim, Mi-Ok;Steiner, Peter M.
    • Communications for Statistical Applications and Methods
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    • v.23 no.1
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    • pp.1-20
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    • 2016
  • Causal inference methodologies have been developed for the past decade to estimate the unconfounded effect of an exposure under several key assumptions. These assumptions include, but are not limited to, the stable unit treatment value assumption, the strong ignorability of treatment assignment assumption, and the assumption that propensity scores be bounded away from zero and one (the positivity assumption). Of these assumptions, the first two have received much attention in the literature. Yet the positivity assumption has been recently discussed in only a few papers. Propensity scores of zero or one are indicative of deterministic exposure so that causal effects cannot be defined for these subjects. Therefore, these subjects need to be removed because no comparable comparison groups can be found for such subjects. In this paper, using currently available causal inference methods, we evaluate the effect of arbitrary cutoffs in the distribution of propensity scores and the impact of those decisions on bias and efficiency. We propose a tree-based method that performs well in terms of bias reduction when the definition of positivity is based on a single confounder. This tree-based method can be easily implemented using the statistical software program, R. R code for the studies is available online.

The Relationship between Role Conflict, Job Satisfaction, and Organizational Commitment among Community Healthcare Workers of the Seoul Preventive Project for Metabolic Syndrome (보건소 대사증후군관리사업 참여인력의 역할갈등, 조직몰입, 직무만족 간의 관계)

  • Ryu, Hosihn;Cho, Jeonghyun
    • Journal of Korean Public Health Nursing
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    • v.27 no.1
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    • pp.16-26
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    • 2013
  • Purpose: The aim of this study was to identify a conceptual link between role conflict, job satisfaction, and organizational commitment, with a specific examination on how job satisfaction mediated the relationship between role conflict and organizational commitment, among community healthcare workers. Methods: Participants were 119 community healthcare workers of the Seoul Preventive Project for Metabolic Syndrome at 15 community health centers. Descriptive analysis, correlations analysis, and multiple regression analysis were used for statistical analysis of our data. Additionally, Sobel's test was used to verify the significance of the mediating effect. Results: An inverse association between role conflict and organizational commitment was found (beta=-0.53, p<.001). This relationship was fully mediated by job satisfaction (z=-6.43, p<.001). Conclusion: Job satisfaction mediates the effects of role conflict on the organizational commitment of healthcare workers in community health centers. Strategies for improving the components of job satisfaction are needed to achieve better outcomes in organizational commitment in the Seoul Preventive Project for Metabolic Syndrome and possibly other work settings.

The Effects of Self-esteem, Stress, and Social Support on Depression among Middle-aged Women (자아존중감, 스트레스 및 사회적 지지가 중년 여성의 우울에 미치는 영향)

  • Lee, Hung Sa;Ko, Young
    • Journal of Korean Public Health Nursing
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    • v.31 no.1
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    • pp.58-70
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    • 2017
  • Purpose: This study was conducted to determine if women's depression is influenced by their self esteem, stress, and social support. Methods: This study was a descriptive survey, and data were collected from the November 1 to December 20, 2015 using a self-reported questionnaire. The measurements were SES for self esteem, and CES-D for depression. A total of 165 middle-aged women participated through convenient sampling. Results: There were significant difference in self-esteem according to education level and monthly income. Additionally, there was an inverse correlation between stress and self esteem, as well as a significant strong correlation between self esteem, stress, social support and depression. Finally, multiple regression showed that self-esteem and stress had significant effects on depression, and their explanatory power was ${\Delta}R2(%)=47.9$ (${\Delta}F=66.526$, p<.001), p<.001). Conclusion: This study confirmed that depression was closely related to self-esteem and stress among middle-aged women. Based on these findings, we suggest that the health policies of reducing depression for middle-aged women should focus on reducing stress and reinforcing their self-esteem.

Thermal Deformation Error Analysis and Experiment of a Linear Motor (Linear Motor의 열변형 오차해석 및 실험)

  • 최우혁;민경석;오준모;최우천;홍대희
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.286-289
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    • 1997
  • In the design of structure the forces acting on the structure are important parameter for noise and vibration control. However, in the complex structure, the forces at the injection pomt on the structure cannot be measured directly. Thus it is necessary to find out indirect force evaluation method. In thls paper forces have been measured with in-situ vibration responses and system information. Three existing techniques of indirect force measurement, viz. direct inverse, principal component analysis and regularization have been compared. It has been shown that multi-vibration responses are essential for the precise estimation of the forces. To satisfy those cond~tions, Rotary compressor is adopted as test sample, because it is very difficult to measurc the injection forces from internal excitat~on to shell. It has also been obtained that relatively higher force IS transmitted through three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation wlth curvature shell and plate and is investigated the possibility of force evaluation of rotary compressor as a complex structure.

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Impact of Board Characteristics on Bank Risk: The Case of Vietnam

  • TRAN, Tu T.T.;DO, Nhung H.;NGUYEN, Yen T.
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.9
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    • pp.377-388
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    • 2020
  • The research identifies hypotheses evaluating the impact of board characteristics on the risk of the commercial bank as well as examining the determinants of bank risk in Vietnam over a 10-year period, starting from 2008. Also, in this research, the differences between the roles of women and men in decision-making are tested. Based on this decision, risks of the banks may arise. Ordinary least squares(OLS) regression, Random effect method, and Fixed effect method are used to estimate the factors that have an impact on bank risk for dataset of all commercial banks in Vietnam. The results found that equity-to-asset ratio, bank performance and the economic growth have an inverse relationship with bank risk, while the size of bank has a positive relationship with the bank risk. One of the highlights of this paper is a demonstration of the relationship between CEO's gender and bank risk. The test result shows that the bank led by a female faces a higher overall risk level and credit risk than a bank led by a male. Based on this result, the paper also makes recommendations to Government, the State Bank of Vietnam and the commercial banks for effective risk management.

A Study on Housewives' Perception, Interest and Consumption of Health Drinks Made in a Health Food Stores (건강원에서 제조한 건강음료에 대한 주부의 인식, 관심 및 소비에 관한 연구)

  • 김현아;박복희
    • Korean Journal of Community Nutrition
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    • v.3 no.1
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    • pp.107-115
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    • 1998
  • This study was conducted to investigate housewives' perception, interest and consumption of health drinks made in a health food stores, and to assess the relationsh- ip between nutritionally-related-variables and the consumption of health drinks. Data was collected from 518 housewives in Chonnam province. Among many items which housewives perceived about health drinks, three factors of 'preference·health-care', ' quality·convenience' and 'price' were found to be represented. Housewives' perception of 'preference·health-care' was negatively correlated with nutritional knowledge. However, a positive correlation between the 'quality·convenience' and eating habits was found. Consumption of health drinks was positively correlated with the diet management score, the perception and interest in health drinks. However, the inverse relationship between consumption of health drinks and nutritional knowledge was observed. Multiple regression analysis showed that the interest and factors of perception of health drinks. Consumption of health drinks was not based upon accurate knowledge concerning nutrition, but was based upon the consumers' perception of taste preference and healthful quality. Therefore, there is a need to educate consumers about the nutritional value of health drinks and how to use nutritional supplements.

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Prediction of Initial Design Parameter of Rectangular Shaped Mold Spring Using Finite Element Method (유한요소법을 이용한 사각단면 금형스프링의 초기 설계변수 예측)

  • Lee, H.W.
    • Transactions of Materials Processing
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    • v.20 no.6
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    • pp.450-455
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    • 2011
  • This paper presents an inverse design methodology for the cross section geometry of mold spring with a rectangular cross section as the starting material for a coiling process. The cross-sections of mold springs are universally rectangular, as the parallel sides minimize the possibility of failure under high service loads. Pre-coiled wires are initially designed to have a trapezoidal cross section, which becomes a rectangle by the coiling process. This study demonstrates a numerical exercise to predict changes in the sectional geometry in spring manufacture and to obtain the initial cross section which becomes the exact rectangle desired from the manufacturing process. Finite element analysis was carried out to calculate the sectional changes for various mold springs. Geometrical parameters were the widths at inner and outer radii, the inner and the outer corner radii, and the height. A partial least square regression analysis was carried out to find the main contributing factors for deciding initial design values. The height and the width mainly affected various initial parameters. The initial width at the inner radius was mostly affected by various specification parameters.

Estimation for Raw Water Quality of Manganese Concentrations from Archived Data in Small-scale Water Systems (소규모 정수처리장에서 모니터링 자료를 이용한 원수의 망간농도 예측에 관한 연구)

  • Min, Byung-Dae;Yamazaki Kimiko;Koizumi Akira;Koo, Ja-Yong
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.4
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    • pp.547-554
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    • 2011
  • In small-scale water systems, the measurement of quality of raw water in running water is generally implemented when the quality of water is stable and frequency of measurement is low. However, units such as water temperature and pH, which are easily monitored, are frequently measured. In establishing an improvement plan for a water treatment system, the range of concentration of the target material present in the raw water of the running water provides relevant information. If the concentration of target material can be specified by the quality of water of data items that are measured daily, inverse estimation of the range of concentration is possible as well. In this paper, we took note of manganese in the raw water from Ogasawara-mura, Tokyo, and estimated the manganese concentration in the raw water of the running water for the past five years. Based on the results obtained, we have proposed a manganese removal system, considering the current situation and geographical conditions of Ogasawara-mura.