• 품질경영학회지
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• 제40권3호
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• pp.347-358
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• 2012

Purpose: Given the mixture components - process variables experimental data, we propose the strategy to find the proper combined model. Methods: Process variables are factors in an experiment that are not mixture components but could affect the blending properties of the mixture ingredients. For example, the effectiveness of an etching solution which is measured as an etch rate is not only a function of the proportions of the three acids that are combined to form the mixture, but also depends on the temperature of the solution and the agitation rate. Efficient designs for the mixture components - process variables experiments depend on the mixture components - process variables model which is called a combined model. We often use the product model between the canonical polynomial model for the mixture and process variables model as a combined model. Results: First we choose the reasonable starting models among the class of admissible product models and practical combined models suggested by Lim(2011) based on the model selection criteria and then, search for candidate models which are subset models of the starting model by the sequential variables selection method or all possible regressions procedure. Conclusion: Good candidate models are screened by the evaluation of model selection criteria and checking the residual plots for the validity of the model assumption. The strategy to find the proper combined model is illustrated with examples in this paper.

• 한국식품영양학회지
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• 제21권1호
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• pp.97-105
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• 2008

An IPA model was used to evaluate customer service encounters at a large food court; also the gaps between importance and performance from were also evaluated from both perspectives. The findings of this study will be applied in order to improve service quality at various large food service operations. A total of 298 customers from a large shopping mall food court completed the study questionnaire, asking them to evaluate the important and performance attributes of service. Seven underlying dimensions were identified and labeled by factor analysis: factor 1 was "safety": factor 2 "time": factor 3 "atmosphere": factor 4 "quality of food": factor 5 "menu attributes": factor 6 "comfort": and the last and seventh factor was "comprehension". As a result of IPA analysis the overall mean scores between the importance attributes and performance attributes showed significant differences by independent t-tests(p<0.001). Quadrant I was classified with unnecessary items including interior design, proper lighting, suitable chairs, and proper room temperature. In quadrant II thirteen variables showed high scores for both importance and performance, such as various menu choices, hygienic food, dishes, chairs, food court, kitchen, and employees; proper ventilation, employee kindness, waiting time to order, and received food; automatic system for ordering-serving. Quadrant III included eight variables identified as low priority, including appearance of food, nutrient content of food, proper portions, new menu, proper music, proper location of cashier, services for children and efficiency of movement. In quadrant IV six variables were included as areas to focus management's efforts, such as food taste, proper food temperature, use of safe food materials, maintenance of food quality, existence of preferred foods, and proper food prices. These results suggest that food court customers have interests that are distinct from restaurant customers and may need to be treated differently. It is anticipated that this data will be useful to the foodservice industry in order to segment customer characteristics by different dinning behaviors.

• 농촌지도와개발
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• 제13권1호
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• pp.29-47
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• 2006

The objectives of this study were to explore rural elderly's perception on rural area as a proper place to live for the elders and to find out their residential satisfaction and its related variables. The data were gathered through the questionnaire survey from 241 rural elderly over 70 aged living in Gyeonggi province during July 2005. The major findings of this study were as follows: 1) Those who are men, having experience living in urban area, and favorable perception to social relation with other residences prefer the rural area to urban area as living place for the elderly ; 2) Those who are subjectively perceived healthy and favorable perception to social relation with other residences tend to be in higher residential satisfaction than other groups ; 3) Such variables as age, educational background, living term in community and urban area were not significant to rural elderly's perception on rural area as a proper place to live for the elders and residential satisfaction; 4) Such variables as identification as community residences, people-oriented personality, sex and having experience living in urban area explained 26.4% of variance in rural elderly's perception on rural area as a proper place to live for the elders ; 5) Such three variables as identification as community residences, relationship with the primary group and age explained 55.2% of variances in residential satisfaction; 6) In shortly, the most influential factor to rural elderly's perception on rural area as a proper place to live for the elder and residential satisfaction was their identification as community residences.

• 대한수학회지
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• 제40권3호
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• pp.341-371
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• 2003

This article discusses in detail how the study of proper holomorphic rational mappings between balls in different dimensions relates to positivity conditions and to isometric imbedding of holomorphic bundles. The first chapter discusses rational proper mappings between balls; the second chapter discusses seven distinct positivity conditions for real-valued polynomials in several complex variables; the third chapter reveals how these issues relate to an isometric imbedding theorem for holomorphic vector bundles proved by the author and Catlin.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제35권3호
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• pp.257-275
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• 2021

본 연구는 예비교사가 변수와 관련된 학생의 사고를 어떻게 파악하고 대응하는지를 조사하는 것을 목적으로 하였다. 변수와 관련된 학생들의 사고를 추론하여 그에 따른 지도방안을 제시해 보게 하는 문항에서 예비교사의 주목하기와 해석하기의 특징을 동시에 살펴보았으며 주목하기와 해석하기에 따라 예비교사의 대응하기가 어떻게 제안되었는지 그 특징을 조사하였다. 예비교사 26명의 응답을 분석한 결과, 예비교사들이 학생들의 응답에서 나타나는 변수에 대한 오개념에 주목하기가 쉽지 않음을 보여주었으며, 주목은 하였으나 적절한 해석을 해내지 못한 경우를 확인할 수 있었다. 주목하지 못하고 해석하지 못한 대부분 예비교사는 변수에 대한 전반적인 이해의 부족으로 인해 적절한 대응을 제시하지 못한 것으로 나타났으며, 주목하기와 해석하기가 성공적으로 이루어졌다 하더라도 경험적 지식의 부족으로 인해 적절한 대응을 제시하지 못하였다. 연구 결과를 바탕으로, 예비교사 교육에 주는 시사점을 논의하였다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.27-30
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• 1996

Determination of input variables for artificial neural network (ANN) depends entirely on the judgement of a modeller. As the number of input variables increases, the training time for the resulting ANN increases exponentially. Moreover, larger number of input variables does not guarantee better performance. In this research, we employ Genetic Algorithm for selecting proper input variables that yield the best performance in training the resulting ANN.

• 수산경영론집
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• 제44권1호
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• pp.59-70
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• 2013

The purpose of this paper is to integrate various models of price formation and let the data choose the most proper model. After the data choose the proper model, one can analyze the price formation process and demand structures for fishery resources under the restriction of Korean fisheries regulations. This study suggests the integrated model including quasi-linear price formation model, Translog price formation model, AIDS price formation model and Lewbel price formation model as level variables. It also suggests another integrated model including AIDS price formation model, Rotterdam price formation model, Latinen-Theil price formation model and Neves price formation model as difference variables. The empirical results show that the AIDS price formation model is the most preferred in both level and difference variables of fishery resources. The estimated parameters show that all sample species have (-) sign of price flexibilities, thus following the law of demand. The scale flexibilities of all species are estimated as (-) sign, thus being adapted to the theory. The contribution and results are summarized as follows. First, the integrated model of fishery market demand has been developed and the data can choose the proper model without arbitrary choice of the researcher. Second, the fishery market demand structure could be analyzed in a way different from the ordinary demand analysis, which is based upon price flexibility and scale flexibility. Third, the integrated model for fishery resources can be used easily when catching restrictions are imposed by policies.

• Wind and Structures
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• 제38권1호
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• pp.1-13
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• 2024

In order to effectively simulate nonstationary stochastic turbulent wind fields, four separation hybrid (SEP-H) models are proposed in the present study. Based on the assumption that the lateral turbulence component at one single-point is uncorrelated with the longitudinal and vertical turbulence components, the fluctuating wind is separated into 2nV-1D and nV1D nonstationary stochastic vector processes. The first process can be expressed as double proper orthogonal decomposition (DPOD) or proper orthogonal decomposition and spectral representation method (POD-SRM), and the second process can be expressed as POD or SRM. On this basis, four SEP-H models of nonstationary stochastic turbulent wind fields are developed. In addition, the orthogonal random variables in the SEP-H models are presented as random orthogonal functions of elementary random variables. Meanwhile, the number theoretical method (NTM) is conveniently adopted to select representative points set of the elementary random variables. The POD-FFT (Fast Fourier transform) technique is introduced in frequency to give full play to the computational efficiency of the SEP-H models. Finally, taking a long-span bridge as the engineering background, the SEP-H models are compared with the dimension-reduction DPOD (DR-DPOD) model to verify the effectiveness and superiority of the proposed models.

• 대한간호학회지
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• 제28권2호
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• pp.256-269
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• 1998

The purpose of this study was to evaluate the usefulness of variables which were known to be related to blood pressure for discriminating between hypertensive and normotensive groups. Variables were obesity, serum lipids, life style-related variables such as smoking, alcohol, exercise, and stress, and demographic variables such as age, economical status, and education. The data were collected from 400 male clients who visited one university hospital located in Incheon, Republic of Korea, from May 1996 to December 1996 for a regular physical examination. Variables which showed significance for discriminating systolic blood pressure in this study were age, serum lipids, education, HDL, exercise, total cholesterol, body fat percent, alcohol, stress, and smoking(in order of significance). By using the combination of these variables, the possibility of proper prediction for a high-systolic pressure group was 2%, predicting a normal-systolic pressure group was 70.3%, and total Hit Ratio was 70%. Variables which showed significance for discriminating diastolic blood pressure were exercise, triglyceride, alcohol, smoking, economical status, age, and BMI (in order of significance). By using the combination of these variables, the possibility of proper prediction for a high-diastolic pressure group was 71.2%, predicting a normal-diastolic pressure group was 71.3%, and total Hit Ratio was 71.3%. Multiple regression analysis was performed to examine the association of systolic blood pressure with life style-related variables after adjustment for obesity, serum lipids, and demographic variables. First, the effect of demographic variable alone on the systolic blood pressure was statistically significant (p=.000) and adjusted $R^2$was 0.09. Adding the variable obesity on demographic variables resulted in raising adjusted $R^2$to 0.11 (p=.000) : therefore, the contribution rate of obesity on the systolic blood pressure was 2.0%. On the next step, adding the variable serum lipids on the obesity and demographic variables resulted in raising adjusted R2 to 0.12(P=.000) : therefore, the contribution rate of serum lipid on the systolic pressure was 1.0%. Finally, adding life style-related variables on all other variables resulted in raising the adjusted $R^2$to 0.18(p=.000) ; therefore, the contribution rate of life style-related variables on the systolic blood pressure after adjustment for obesity, serum lipids, and demographic variables was 6.0%. Multiple regression analysis was also performed to examine the association of diastolic blood pressure with life style-related variables after adjustment for obesity, serum lipids, and demographic variables. First, the effect of demographic variable alone on the diastolic blood pressure was statistically significant (p=.01) and adjusted $R^2$was 0.03. Adding the variable obesity on demographic variables resulted in raising adjusted $R^2$to 0.06 (p=.000) ; therefore, the contribution rate of obesity on the diastolic blood pressure was 3.0%. On the next step, adding the variable serum lipids on the obesity and demographic variables resulted in raising the adjusted $R^2$ to 0.09(p=.000) ; therefore, the contribution rate of serum lipid on the diastolic pressure was 3.0%. Finally, adding life style-related variables on all other variables resulted in raising the adjusted $R^2$ to 0.12 (p=.000) : therefore, the contribution rate of life style-related variables on the systolic blood pressure after adjustment for obesity, serum lipids, and demographic variables was 3.0%.

• 산업기술연구
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• 제22권A호
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• pp.127-135
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• 2002

In this study, the preliminary risk assessment for the underground storage tanks(UST) in Chunchon city was implemented using the geographical information system(GIS). The estimation variables, such as the installation year, storage capacity, the distances from streams, and from groundwater pumping wells, were selected to estimate the relative risk levels. The weighting factors were given to all the estimation variables. Cumulative scores were induced by the combination of all the scores of the corresponding variables using the buffering technique and the overlay analysis in ArcView. Using the these process, the relative risk level of each UST was estimated. Some sites in this study are simplified and reduced because the number of useable data are limited or too enormous. Thus the selection of the comprehensive estimation variables and the proper weighting values are required for the future study. The methodology in this study could be served not only for the preliminary risk assessment of UST but also for the selection of the proper location of new and old UST. And, it can be used for the effective management system of UST.