• Title, Summary, Keyword: Correlation Coefficient

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On the Effect of Significance of Correlation Coefficient for Recommender System

  • Lee, Hee-Choon
    • Journal of the Korean Data and Information Science Society
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    • v.17 no.4
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    • pp.1129-1139
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    • 2006
  • Pearson's correlation coefficient and vector similarity are generally applied to The users' similarity weight of user based recommender system. This study is needed to find that the correlation coefficient of similarity weight is effected by the number of pair response and significance probability. From the classified correlation coefficient by the significance probability test on the correlation coefficient and pair of response, the change of MAE is studied by comparing the predicted precision of the two. The results are experimentally related with the change of MAE from the significant correlation coefficient and the number of pair response.

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The relationship between prediction accuracy and pre-information in collaborative filtering system

  • Kim, Sun-Ok
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.4
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    • pp.803-811
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    • 2010
  • This study analyzes the characteristics of preference ratings by dividing estimated values into four groups according to rank correlation coefficient after obtaining preference estimated value to user's ratings by using collaborative filtering algorithm. It is known that the value of standard error of skewness and standard error of kurtosis lower in the group of higher rank correlation coefficient This explains that the preference of higher rank correlation coefficient has lower extreme values and the differences of preference rating values. In addition, top n recommendation lists are made after obtaining rank fitting by using the result ranks of prediction value and the ranks of real rated values, and this top n is applied to the four groups. The value of top n recommendation is calculated higher in the group of higher rank correlation coefficient, and the recommendation accuracy in the group of higher rank correlation coefficient is higher than that in the group of lower rank correlation coefficient Thus, when using standard error of skewness and standard error of kurtosis in recommender system, rank correlation coefficient can be higher, and so the accuracy of recommendation prediction can be increased.

A Study on the Effect of Co-Ratings and Correlation Coefficient for Recommender System

  • Lee, Hee-Choon;Lee, Seok-Jun;Park, Ji-Won;Kim, Chul-Seung
    • 한국데이터정보과학회:학술대회논문집
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    • pp.59-69
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    • 2006
  • Pearson's correlation coefficient and Vector similarity are generally applied to The users' similarity weight of user based recommender system. This study is needed to find that the correlation coefficient of similarity weight is effected by the number of pair response and significance probability. From the classified correlation coefficient by the significance probability test on the correlation coefficient and pair of response, the change of MAE is studied by comparing the predicted precision of the two. The results are experimentally related with the change of MAE from the significant correlation coefficient and the number of pair response.

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Correlation Analysis of the Dielectric Breakdown Voltage of Liquid Nitrogen (액체질소 절연파괴전압의 상관 분석)

  • Baek, Seung-Myeong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.6
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    • pp.396-399
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    • 2015
  • We analyzed the correlation between breakdown voltage(BDV) of liquid nitrogen(LN2) and factors. The chosen factors affecting the breakdown are the diameter of electrode, gap length, temperature of LN2, and pressure of LN2. The BDV of LN2 was increased with increasing the diameter, the gap length and the pressure. And The BDV of LN2 was increased with decreasing the temperature. However, correlation coefficient was different from each other depending on the situation. The BDV exhibited a very high correlation coefficient of 0.92227 to dependence on the diameter. And a very high correlation coefficient of 0.94980 to dependence on the pressure under sphere(D 7.5 mm)-plane electrode. When the pressure is applied, sphere-plane electrode is the correlation coefficient was higher than that of the needle-plane electrode. It shows the dependence of a temperature coefficient of -0.758290 ~ -0.39946 under needle-plane electrode.

A Comment for Teaching Correlation Coefficient in Elementary Statistics Course

  • Oh, Myong-Sik
    • Communications for Statistical Applications and Methods
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    • v.14 no.2
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    • pp.301-307
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    • 2007
  • A effective teaching method on correlation coefficient for elementary level statistics course is discussed in this article. The well known inequalities, such as Theorem 368 of Hardy et al. (1952), are used for the interpretation of concept of covariance. An Excel example is provided for the illustration of concept of correlation coefficient.

Rainfall Adjust and Forecasting in Seoul Using a Artificial Neural Network Technique Including a Correlation Coefficient (인공신경망기법에 상관계수를 고려한 서울 강우관측 지점 간의 강우보완 및 예측)

  • Ahn, Jeong-Whan;Jung, Hee-Sun;Park, In-Chan;Cho, Won-Cheol
    • 한국방재학회:학술대회논문집
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    • pp.101-104
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    • 2008
  • In this study, rainfall adjust and forecasting using artificial neural network(ANN) which includes a correlation coefficient is application in Seoul region. It analyzed one-hour rainfall data which has been reported in 25 region in seoul during from 2000 to 2006 at rainfall observatory by AWS. The ANN learning algorithm apply for input data that each region using cross-correlation will use the highest correlation coefficient region. In addition, rainfall adjust analyzed the minimum error based on correlation coefficient and determination coefficient related to the input region. ANN model used back-propagation algorithm for learning algorithm. In case of the back-propagation algorithm, many attempts and efforts are required to find the optimum neural network structure as applied model. This is calculated similar to the observed rainfall that the correlation coefficient was 0.98 in missing rainfall adjust at 10 region. As a result, ANN model has been for suitable for rainfall adjust. It is considered that the result will be more accurate when it includes climate data affecting rainfall.

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A study on the body type of the Korean from a point of view of the Clothing Construction - Standard sizing and correlation among the measurement - (한국인 체형에 관한 피복구성학적인 연구 (II) - 기본치수와 상관관계 -)

  • 이순원
    • Journal of the Korean Home Economics Association
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    • v.11 no.1
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    • pp.14-25
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    • 1973
  • The measurements includings 22 items such as height, weight, body width were carried out for Korean male and female students, one hundred each, from 18 to 24 years old. The correlation coefficient was calculated for every two items. The values are basic for the Clothing construction and the Pattern grading. The results are as follows : 1) The measuring values are as shown in Table 1 and the index are as shown in Table 2. 2) The correlation coefficient of length to length is larger than that of length to girth and that of length to width. The correlation coefficient of girth to girth is larger than girth to length and that of girth to width. The correlation coefficient of width to width does not show remarkable difference from those of others. 3) The correlation coefficient values of weight to lengths, weight to lengths, weight to girths and weight to width are larger. Among these, the correlation coefficient of weight to girths is the largest. 4) The correlation coefficient in general shows almost positive values except a few exception showing negative values. 5) No meaning differences are found between males and females.

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Adjustment of load correlation coefficient for advanced load management (부하관리 개선을 위한 부하 상관계수 산정에 관한 연구)

  • Park, Chang-Ho;Cho, Seong-Soo;Kim, Gi-Hyun;Im, Jin-Soon;Kim, Du-Bong;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • pp.1267-1269
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    • 1999
  • This paper studies on arrangement of load correlation coefficient for advanced load management. To accurate load correlation coefficient, we used two real factors, electrical energy(kWh) and peak load current of pole transformers, acquired by measuring instrument. Out of several correlation equations, we find that the quadratic equation is the most accurate to express peak load current and working electrical energy. If the data is located in the outside of ${\pm}3{\sigma}$ it is discarded. For load management, we rearranged load correlation coefficient considering +2${\sigma}$ at load correlation equation. Comparing conventional load correlation coefficient with rearranged one, we can get the result of error reduced and it is adjacent to the actual data. It will be used peak load forecasting from working electrical energy and we are able to prevent from the damaging of pole transformer due to overload.

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A study of the correlation coefficients with respect to the degrees of the global models in the kriging metamodel (크리깅 메타모델에서 전역 모델에 따른 상관계수의 연구)

  • Cho, Su-Kil;Lee, Tae-Hee
    • Proceedings of the KSME Conference
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    • pp.701-705
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    • 2008
  • Design analysis and computer experiments (DACE) model is widely used to express efficiently the nonlinear responses in the field of engineering design. Kriging model, a DACE model, can approximately replace a simulation model that is very expensive or highly nonlinear. The kriging model is composed of the summation of a global model and a local model representing deviation from global model. The local model is determined by correlation coefficient of the pre-sampled points, where determination of the correct correlation coefficient has an effect on accuracy and robustness of the kriging model. Therefore, robustness of the correlation coefficient is explored with respect to degrees of the global model. Then we propose the range of correlation coefficient to make correct and robust kriging model and the influence of the correlation coefficients on the degrees of global model with respect to the nonlinearity of the pre-sampled responses.

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Correlation coefficient between generalized intuitionistic fuzzy sets (일반화된 직관적 퍼지집합들의 상관계수)

  • Park Jin-Han;Park Yong-Beom;Lee Bu-Young
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.61-64
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    • 2006
  • Based on the geometrical representation of a generalized intuitionistic fuzzy set, we take into account all three parameters describing generalized intuitionistic fuzzy set, propose a method to calculate the correlation coefficient for generalized intuitionistic fuzzy sets in finite set and probability space, respectively, and discuss some properties of correlation and correlation coefficient of generalized intuitionistic fuzzy sets.

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