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排序方式: 共有135条查询结果,搜索用时 31 毫秒
11.
In the Property and Casualty (P&C) ratemaking process, it is critical to understand the effect of policyholders’ risk profile to the number and amount of claims, the dependence among various business lines and the claim distributions. To include all the above features, it is essential to develop a regression model which is flexible and theoretically justified. Motivated by the issues above, we propose a class of logit-weighted reduced mixture of experts (LRMoE) models for multivariate claim frequencies or severities distributions. LRMoE is interpretable, as it has two components: Gating functions, which classify policyholders into various latent sub-classes; and Expert functions, which govern the distributional properties of the claims. Also, upon the development of denseness theory in regression setting, we can heuristically interpret the LRMoE as a “fully flexible” model to capture any distributional, dependence and regression structures subject to a denseness condition. Further, the mathematical tractability of the LRMoE is guaranteed since it satisfies various marginalization and moment properties. Finally, we discuss some special choices of expert functions that make the corresponding LRMoE “fully flexible”. In the subsequent paper (Fung et al., 2019b), we will focus on the estimation and application aspects of the LRMoE. 相似文献
12.
LI Guohui CHEN Liaoyuan LUO Cuiwen 《核工业西南物理研究院年报(英文版)》2005,(1):82-84
In HL-2A tokamak experiment, high speed image acquisitoin system grabs images and shows them in real-time. It provides serial images of discharge to help scientists a lot to analyse the experiment. Neutral particle count system counts the number of neutral particles radiated from fusion plasmas. It provides the data to calculate the ion energy. 相似文献
13.
Positronium time of flight spectroscopy(Ps-TOF)is an effective technique for porous material research.It has advantages over other techniques for analyzing the porosity and pore tortuosity of materials.This paper describes a design for Ps-TOF apparatus based on the Beijing intense slow positron beam,supplying a new material characterization technique.In order to improve the time resolution and increase the count rate of the apparatus,the detector system is optimized.For 3 eV o-Ps,the time broadening is 7.66 ns and the count rate is 3 cps after correction. 相似文献
14.
This paper considers the pricing of contingent claims using an approach developed and used in insurance pricing. The approach is of interest and significance because of the increased integration of insurance and financial markets and also because insurance-related risks are trading in financial markets as a result of securitization and new contracts on futures exchanges. This approach uses probability distortion functions as the dual of the utility functions used in financial theory. The pricing formula is the same as the Black-Scholes formula for contingent claims when the underlying asset price is log-normal. The paper compares the probability distortion function approach with that based on financial theory. The theory underlying the approaches is set out and limitations on the use of the insurance-based approach are illustrated. The probability distortion approach is extended to the pricing of contingent claims for more general assumptions than those used for Black-Scholes option pricing. 相似文献
15.
Pakawat Chammanee Kwannate Sombatsompop Apisit Kositchaiyong Narongrit Sombatsompop 《Journal of Macromolecular Science: Physics》2013,52(4):755-765
The anti-bacterial efficacy of medium-density polyethylene (MDPE) with various contents of different anti-bacterial agents was studied with respect to the effects of the anti-bacterial concentration, size and form of MDPE test-specimen, and the contact time. The three anti-bacterial agents used were carbendazim and zinc dimethyl dithiocarbamate (TROYSAN-S88), 2-hydroxypropyl3-piperazinyl-quinoline carboxylic acid methacrylate (HPQM), and silver substituted zeolite (ZEOMIC). The halo and plate-count-agar (PCA) tests were employed to assess the efficacies of the anti-bacterial performance. It was found that the inhibition zone from the halo test was most visible for the HPQM agent; the higher the HPQM content, the greater the inhibition zone. ZEOMIC exhibited no inhibition zone. The PCA test results suggested that after incorporating HPQM agent in the MDPE matrix, the% reductions of E. coli and S. aureus bacteria were as successfully high as 99.9% for all HPQM loadings. 相似文献
16.
Researchers in actuarial sciences have investigated the tail behavior of the LCR and ECOMOR reinsurance treaties separately for managing extreme risks in reinsurance business. In practice, a reinsurance company may possess these two treaties simultaneously. Therefore, investigating the joint tail behavior of these two treaties is practically useful in risk management. This paper derives the asymptotic limit of the joint tail of these two reinsurance treaties under the setup of Jiang and Tang (2008). 相似文献
17.
We analyze the concept of credibility in claim frequency in two generalized count models–Mittag-Leffler and Weibull count models–which can handle both underdispersion and overdispersion in count data and nest the commonly used Poisson model as a special case. We find evidence, using data from a Danish insurance company, that the simple Poisson model can set the credibility weight to one even when there are only three years of individual experience data resulting from large heterogeneity among policyholders, and in doing so, it can thus break down the credibility model. The generalized count models, on the other hand, allow the weight to adjust according to the number of years of experience available. We propose parametric estimators for the structural parameters in the credibility formula using the mean and variance of the assumed distributions and a maximum likelihood estimation over a collective data. As an example, we show that the proposed parameters from Mittag-Leffler provide weights that are consistent with the idea of credibility. A simulation study is carried out investigating the stability of the maximum likelihood estimates from the Weibull count model. Finally, we extend the analyses to multidimensional lines and explain how our approach can be used in selecting profitable customers in cross-selling; customers can now be selected by estimating a function of their unknown risk profiles, which is the mean of the assumed distribution on their number of claims. 相似文献
18.
Fokwa BP Lueken H Dronskowski R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(21):6040-6046
Single crystals of the complex boride series Sc(2)FeRu(5-n)Rh(n)B(2) (n=1, 3, 4) were synthesized by arc-melting the elements in water-cooled copper crucibles under argon atmospheres and were chemically characterized by single-crystal XRD and EDX analyses. The new compounds are isotypic and crystallize in the tetragonal space group P4/mbm with Z=2, adopting a substitutional variant of the Ti(3)Co(5)B(2)-type structure. The magnetically active iron atoms are arranged in chains with intra- and interchain distances of about 3.02 and 6.60 A, respectively. Strong ferromagnetic interactions are observed for both Sc(2)FeRuRh(4)B(2) (64 valence electrons (VE), TC approximately 350 K, mu(a)=3.1 mu(B)) and Sc(2)FeRu(2)Rh(3)B(2) (63 VE, T(C) approximately 300 K, mu(a)=3.0 mu(B)), whereas antiferromagnetic interactions are found in the case of Sc(2)FeRu(4)RhB(2) (61 VE, T(N) approximately 10 K, mu(eff)=3.2): The magnetism of the entire Sc(2)FeRu(5-n)Rh(n)B(2) (0相似文献
19.
20.
整体X光透镜性能实验研究 总被引:6,自引:2,他引:4
利用高计数率探测器和低功率光源,在大的能量范围内,同时测量了整体X光透镜的传输效率和焦斑直径与能量的关系。实验结果表明:透镜的焦斑直径随着能量的升高而减小;对04-5-10-5透镜而言,在高于5.8keV的能量范围内,透镜的传输效率随着能量的升高而降低,在低于5.8keV的能量范围内,透镜的传输效率随着能量的升高而增加。通过测量不同能量的X射线在透镜会聚光束中的空间分布,研究了短出口焦距透镜的光晕现象,光晕会导致透镜焦斑直径增大和传输效率测量值的增加。利用轴向扫描法研究了整体X光透镜出口焦距和能量的关系,实验结果表明:会聚透镜的出口焦距随着X射线能量的升高而增加。 相似文献