522 research outputs found
Functional Multidimensional Scaling
Multidimensional scaling is an important component in analyzing proximity (similarity or dissimilarity) between objects and plays a key role in creating low-dimensional visualizations of objects. Regardless of the progress in this area, traditional solutions of multidimensional scaling problems are inapplicable to the proximity which change in time. In this dissertation, we focus on dissimilarity instead of similarity. Motivated by the studies of functional data analysis, we extend the current multidimensional scaling techniques and propose a functional method to obtain lower-dimensional smooth representations in terms of time-varying dissimilarities. This method incorporates the smoothness approach of functional data analysis by using cubic B-spline basis functions. The model is also designed to arrive at optimal representations such that dissimilarities evaluated by estimated representations are almost the same as original dissimilarities of objects in a low dimension which is easier for people to recognize. We verify the feasibility of the model by running simulations, as well as using the closing prices of the S&P 500 stocks as a real case to analyze their dissimilarities. This case study reconstructs the 500 stocks with this functional multidimensional scaling method and provides us a good visualization on a 2D map for the 500 stocks so that we can see how their dissimilarities change smoothly in each month of the year 2018. Following the analysis of all of the 500 stocks, the cluster analysis of the first 15 stocks is displayed based on some conditions so that it helps us see how the stocks move from month to month and offers a new tool to cluster the stocks in the future
Not only Online Review but also its Helpfulness is Manipulated: Evidence from Peer to Peer Lending Forum
Online reviews have become proposed as useful information for consumers to make decision. Meanwhile, review manipulation will weaken the credibility of online reviews. Except manipulating the review text and rating, we propose that review helpfulness, an important signal for consumer to filter the reviews, could also be manipulated. This study thus explores the existence of review helpfulness manipulation and the relationship between firm quality and review manipulation. Based on a dataset from a review forum in www.wdzj.com which is the leading and largest portal of peer to peer lending industry in China, we get the following interesting results. First, due to the manipulation of review helpfulness, a manipulated positive review is more likely to receive higher helpfulness, while a manipulated negative is more likely to get lower helpfulness. Second, a manipulated review tends to be lower quality in terms of readability and word count, which are found as positive predictors for review helpfulness. Third, high quality firms tend to manipulate more positive reviews, and at the same time high quality firms will receive more negative manipulated reviews. This study extends current understanding about online review manipulation, thereby providing theoretical and practice implications
Monitoring of Tsunami/Earthquake Damages by Polarimetric Microwave Remote Sensing Technique
Polarization characterizes the vector state of EM wave. When interacting with polarized wave, rough natural surface often induces dominant surface scattering; building also presents dominant double-bounce scattering. Tsunami/earthquake causes serious destruction just by inundating the land surface and destroying the building. By analyzing the change of surface and double-bounce scattering before and after disaster, we can achieve a monitoring of damages. This constitutes one basic principle of polarimetric microwave remote sensing of tsunami/earthquake. The extraction of surface and double-bounce scattering from coherency matrix is achieved by model-based decomposition. The general four-component scattering power decomposition with unitary transformation (G4U) has been widely used in the remote sensing of tsunami/earthquake to identify surface and double-bounce scattering because it can adaptively enhance surface or double-bounce scattering. Nonetheless, the strict derivation in this chapter conveys that G4U cannot always strengthen the double-bounce scattering in urban area nor strengthen the surface scattering in water or land area unless we adaptively combine G4U and its duality for an extended G4U (EG4U). Experiment on the ALOS-PALSAR datasets of 2011 great Tohoku tsunami/earthquake demonstrates not only the outperformance of EG4U but also the effectiveness of polarimetric remote sensing in the qualitative monitoring and quantitative evaluation of tsunami/earthquake damages
The Value of Backers’ Word-of-Mouth in Screening Crowdfunding Projects: An Empirical Investigation
Reward-based crowdfunding is an emerging financing channel for entrepreneurs to raise money for their innovative projects. How to screen the crowdfunding projects is critical for crowdfunding platform, project founder, and potential backers. This study aims to investigate whether backers’ word-of-mouth (WOM) is a valuable input to generate collective intelligence for project screening. Specially, we answer three questions. First, is backers’ WOM an effective signal for implementation performance of crowdfunding projects? Second, how do the WOM help screen projects during the fund-raising process? Third, which kind of comments (positive or negative) is more effective in screening crowdfunding projects? Research hypotheses were developed based on theories of collective intelligence and WOM communication. Using a cross section dataset and a panel dataset, we get the following findings. First, backers’ negative WOM can effectively predict project implementation performance, however positive WOM does not have that prediction power. The prediction power of positive and negative WOM differs significantly. One possible reason is that negative WOM does contain more information of project quality. Second, project with more accumulative negative WOM tend to attract fewer subsequent backers. However, accumulative positive WOM is not helpful for attracting more potential backers. We conclude that negative WOM is useful for project screening project, because it is a signal of project quality, and meanwhile it could prevent backers make subsequent investments
Relationship between single-nucleotide polymorphisms in un-translated region of human leukocyte antigen-G and preeclampsia
Purpose: The aim of this study was to unravel the link between human leukocyte antigen-G untranslated region (HLA-G 3-UTR) single-nucleotide polymorphism (SNP) and preeclampsia by examining polymorphisms in HLA-G 3-UTR in preeclampsia patients and their newborns, as well as those of women with normal pregnancy and their newborns.Methods: Single pregnant mothers and their newborns at the Third Affiliated Hospital of Zhengzhou University, China, were divided into preeclampsia group (144 cases), and normal pregnancy group (122 cases). Blood samples from the two groups were collected for DNA extraction, and the DNA samples were analyzed for HLA-G 3'-UTR SNP by polymerase chain reaction (RT-PCR) and direct sequencing method.Results: The frequency of CG genotype in HLA-G 3-UTR 3127 gene in the preeclampsia group was significantly lower, while the frequency of AA genotype in HLA-G 3-UTR 3172 gene in the preeclampsia group was significantly higher (p < 0.05) when compared with the normal pregnancy group. Furthermore, frequencies of the compatible genotype AA/AA (mothers/newborns) in HLA-G 3-UTR 3172 gene in the preeclampsia group were significantly higher relative to the normal pregnancy group (p< 0.05).Conclusion: These results suggest that when CC/GG is the compatible genotype in HLA-G 3-UTR 3127 gene of mothers/newborns, preeclampsia risk may decrease, but it may increase if the compatible genotype is AA/AA. Thus, SNP in HLA-G 3-UTR 3127 gene may be a protective factor against preeclampsia in Chinese Han pregnant women, while SNP in 3172 gene may be associated with susceptibility to preeclampsia.Keywords: Single-nucleotide polymorphisms, Human leukocyte antigen-G, Un-translated Region, Preeclampsi
Examining the Factors Influencing Tourists’ Destination: A Case of Nanhai Movie Theme Park in China
The present study used a stimulus-organism-response (S-O-R) theoretical framework to examine the relationship between theme park tourists’ experience, brand identity, brand satisfaction, and brand loyalty in China. By using the structural equation model (CB-SEM), this paper illustrates the process of forming destination brand loyalty for sustainable tourism on theme parks. The results suggested a second-order structure of tourism experience. The first-order four factors have different impacts on the second-order tourism experience. Activity experience is the most important factor influencing tourism experience, followed by environment experience, then facility experience, and finally interaction experience. In terms of tourism experience, individual brand identity-brand satisfaction-brand loyalty is the most important path of a theme park on tourists’ behavioral intention, among which brand satisfaction plays the most significant partial mediation effect in the relationship between individual identity and destination loyalty. It is expected that the results of this study provide a reference for improving tourists’ brand loyalty to achieve sustainable development of theme parks
Darriwilian (Middle Ordovician) graptolites from the northern margin of the Qaidam Basin (Qinghai, China)
A restudy of the early Darriwilian graptolites from the Dameigou section in the Qaidam Basin provides some new information for graptolite biostratigraphy. The section contains a number of biserial faunas and easily identifiable Holmograptus Kozlowski, 1957, which are the marked faunas of the early Darriwilian. According to the biostratigraphic occurrences of the species, the Levisograptus dentatus Zone and the Holmograptus lentus Zone are identified from the Qaidam Basin. At the same time, the identification of these two graptolite zones provides materials for replacing the old, long-ranging Amplexograptus confertus Zone
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