Comment on “Mixture model description of the T-, P dependence of the refractive index of water” [J. Chem. Phys. 114, 3157 (2001)]

2001 ◽  
Vol 115 (16) ◽  
pp. 7795-7795 ◽  
Author(s):  
Allan H. Harvey
Keyword(s):  
Refractive Index ◽  
Mixture Model ◽  
Chem Phys ◽  
Model Description

Mixture model description of the T-, P dependence of the refractive index of water

2001 ◽  
Vol 114 (7) ◽  
pp. 3157-3162 ◽  
Author(s):  
C. H. Cho ◽  
J. Urquidi ◽  
Gregory I. Gellene ◽  
G. Wilse Robinson
Keyword(s):  
Refractive Index ◽  
Mixture Model ◽  
Model Description

scholarly journals Model Description of Similarity-Based Recommendation Systems

Entropy ◽  
2019 ◽  
Vol 21 (7) ◽  
pp. 702
Author(s):  
Takafumi Kanamori ◽  
Naoya Osugi
Keyword(s):  
Mixture Models ◽  
Mixture Model ◽  
Statistical Models ◽  
Recommendation System ◽  
Similarity Measures ◽  
Model Description ◽  
Statistical Interpretation ◽  
Similarity Matrix ◽  
Real World Data ◽  
Completely Positive

The quality of online services highly depends on the accuracy of the recommendations they can provide to users. Researchers have proposed various similarity measures based on the assumption that similar people like or dislike similar items or people, in order to improve the accuracy of their services. Additionally, statistical models, such as the stochastic block models, have been used to understand network structures. In this paper, we discuss the relationship between similarity-based methods and statistical models using the Bernoulli mixture models and the expectation-maximization (EM) algorithm. The Bernoulli mixture model naturally leads to a completely positive matrix as the similarity matrix. We prove that most of the commonly used similarity measures yield completely positive matrices as the similarity matrix. Based on this relationship, we propose an algorithm to transform the similarity matrix to the Bernoulli mixture model. Such a correspondence provides a statistical interpretation to similarity-based methods. Using this algorithm, we conduct numerical experiments using synthetic data and real-world data provided from an online dating site, and report the efficiency of the recommendation system based on the Bernoulli mixture models.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

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