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CN 34-1054/N

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2021 Vol. 51, No. 12

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Research Articles
A robust homogeneity pursuit algorithm for varying coefficient models with longitudinal data
TANG Heng, ZHENG Zhi, ZHANG Weiping
2021, 51(12): 857-867. doi: 10.52396/JUST-2021-0054
Article Views:953 Full article PDF
Abstract:
This article explores the homogeneity of coefficient functions in varying coefficient models where individuals can be classified into different subgroups for each covariate where its varying coefficients are homogeneous in the same subgroup. With repeated measurements, we use B-spline function approximations and the change point detection algorithm to identify the homogeneity. To account for the potential outliers or heavy-tailedness of the observed distribution, we propose to estimate the coefficient functions under the framework of M-estimation, and use least absolute deviation (LAD) loss as an example. Numerical results show that our estimators outperform the commonly used least squares (LS) estimators when existing outliers and heavy-tailedness of observed distribution.
Statistical test for high order stochastic dominance under the density ratio model
ZHOU Yang, QIU Guoxin, ZHUANG Weiwei
2021, 51(12): 868-878. doi: 10.52396/JUST-2021-0179
Article Views:406 Full article PDF
Abstract:
In economics, medicine and other fields, how to compare the dominance relations between two distributions has been widely discussed. Usually population means or medians are compared. However, the population with a higher mean may not be what we will choose, since it may also have a larger variance. Stochastic dominance proposes a good solution to this problem. Subsequently, how to test stochastic dominance relations between two distributions is worth discussing. In this paper, we develop the test statistic of high order stochastic dominance under the density ratio model. In addition, we provide the asymptotic properties of test statistic and use the bootstrap method to obtain p-values to make decisions. Furthermore, the simulation results show that the proposed test statistics have the high test power.
The generating fields of two twisted Kloosterman sums
ZHANG Shenxing
2021, 51(12): 879-888. doi: 10.52396/JUST-2021-0077
Article Views:273 Full article PDF
Abstract:
The generating fields of the twisted Kloosterman sums Kl (q, a, χ) and the partial Gauss sums g(q, a, χ) are studied.We require that the characteristic p is large with respect to the order d of the character χ and the trace of the coefficient a is nonzero.When p≡±1 mod d,we can characterize the generating fields of these character sums.For general p,when a lies in the prime field,we propose a combinatorial condition on (p, d) to ensure one can determine the generating fields.
Lin-Lu-Yau curvature and diameter of amply regular graphs
LI Xintian, LIU Shiping
2021, 51(12): 889-893. doi: 10.52396/JUST-2021-0232
Article Views:355 Full article PDF
Abstract:
By Hall’s marriage theorem, we study lower bounds of the Lin-Lu-Yau curvature of amply regular graphs with girth 3 or 4 under different parameter restrictions.As a consequence,we show that each conference graph has positive Lin-Lu-Yau curvature.Our approach also provides a geometric proof of a known diameter estimates of amply regular graphs in the case of girth 4 and some special cases of girth 3.
Market reaction to tender offers: Insights from China
WANG Yuchen, QIAN Yuanchen
2021, 51(12): 894-911. doi: 10.52396/JUST-2021-0172
Article Views:378 Full article PDF
Abstract:
This article studies the tender offers of Chinese A-share listed companies. We apply the nonparametric method and the piecewise-linear regression model to indicate that the pricing of offers has an anchoring effect. We find that the historical returns positively affect the post-offer price premium. Besides, We use the logistic regression model to find that historical returns significantly influence the success rate of the acquisition. We adopt the event study methods to show that the abnormal return and the abnormal trading volume reach their peaks on the announcement day, revealing the possible existence of informed traders in tender offers.
New product launching: The effect of firm-generated content on purchase intention
ZHANG Kedan, FANG Wenpei, LUO Biao, WAN Liang
2021, 51(12): 912-926. doi: 10.52396/JUST-2021-0107
Article Views:573 Full article PDF
Abstract:
The launching of new products is important for the success of a firm. Nowadays, official brand pages have become one of the main channels to launch new products because of the low cost and high controllability. Firm-generated content (FGC) is a potential signal of product quality and product brand, which gradually turns into the key information for companies to launch new products. In case of the market launch of new products, this study investigates the effect of FGC effectiveness on purchase intention. The online experiment was conducted and data were collected from 423 brand followers on Sina Weibo. The structural equation modeling was used to empirically test the proposed conceptual framework. Findings of the direct effects of the research show that emotional appeal positively affects purchase intention. Informativeness and emotional appeal are the important predictors of the perceived quality and brand attitude, and further influence purchase intention. This study also demonstrates that the perceived quality has a positive impact on the brand attitude, showing that the perceived quality and brand attitude sequentially mediate the effects of FGC effectiveness on purchase intention. The results implicate that a firm should not only serve as an information provider but also serve more as an emotional provider.

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