基于狄利克雷多项式过程模型与K-means结合的菌群分析

群体分型是一种有助于更好的理解人类身心健康等复杂生物学问题的有效方法,聚类是一种为了对样本分组来降低复杂性的定义肠型的方法,而传统K-means聚类算法的K值选取无法确定,本文在传统K-means聚类算法的基础上进行了改进,并公开数据集上进行了验证,实验表明改进算法能够解决K值选取无法确定的问题,且聚类结果的稳定性、准确性和聚类质量都得到显著提高。将改进后的模型运用于肠道菌群OTUs数据,发现不仅能够有效地区分2-型糖尿病患者样本间的相似性,而且能鉴定出影响菌群结构异质性最大的OTUs菌,为临床解决2-型糖尿病问题提供了一种新的思路。

A Population Balance Model for Disperse Systems:Particle Size Distribution in Suspension Polymerization

On the basis of population balance a mathematical model is developed to describe the formation of polymer particle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and the gel effect are analyzed in particular. Parameters of the models are estimated by experimental data on reaction conversion and particle size distribution. The results show that the model is suitable for predicting polymerization processes.

Application of the Game Theory to the Real-Estate Market with State Assistance

The study of bilateral markets, in an equilibrium perspective, began to catch labor economists＇ attention in recent decades since they allow the prediction of market anomalies or flaws. In the study there appears a matching process whose theoretical analysis is known as bilateral assignment model. Among the different examples of bilateral markets and the assignment processes linked with them is the real-estate market. Its characteristics raise problems which affect low-income groups mainly, for which the state＇s mission is critical. These problems motivated the authors of the present work to provide a solution by using the results obtained in the assignment models with capacity restrictions. In this work the study is made of the real-estate market with the variant of the state intervention in housing assignment. The situation raised here is that the state has the task of facilitating low-income people access to housing so that they can participate in the real-estate market. In order to be able to fulfill its work, the state has a list of people willing to sell or rent homes thanks to tax cuts or some compensation offered by the state, for example. However, the state budget is limited and its participation will have a certain quota. Like the bilateral market, this new model solves the problem in which buyers and sellers are assigned to one another so that they can satisfy a property of stability. It is also shown that it is possible to find assignments for which there are no buyer-seller coalitions affecting such stability. A method is shown by means of which it is possible to solve the problem of truncating the benefits given to buyers and sellers under the emergency of budget cut.

Classification of Crystallographic Groups in the Hyperbolic 5-Dimensional Indefinite Space

Let V be a hyperbolic 5-dimensional indefinite space. W is the infinite Weyl group of an irreducible root system. The principal aim of this paper is to classify all crystallgraphic groups associated with W up to conjugation in the affine group A(V).

Analysis of Acoustic Emission Signals Accompanying Growth of Single Aluminum Crystals： Experimental Results and Theoretical Model of the Cluster

The purpose of the work is to identify the acoustic emission （AE） signal in the melt and from the interphase during the crystal growth and to establish the connection between issue parameters： the number of signal events of frequency and the signal power with the growth conditions of temperature gradient and crystallization rate. Experiments on single crystal growth were carried out using hardware and software system which allows to perform spectral Fourier analysis of AE signals and to simultaneously remove the cooling curve for the entire period of crystallization. On the basis of spectral analysis of AE signals, a theoretical model of clusters in the aluminum melt was designed. The experimental results indicate an uneven abrupt advancement of the interface according to the configuration of each individual cluster.

Assessment of the influence of global dimming on the photosynthetic production of rice based on three-dimensional modeling

Observations indicate that global radiation reaching the Earth's surface has gradually decreased over the past several decades(i.e.,the "global dimming" phenomenon),while the fraction of diffuse radiation in global radiation has increased.It has been found that the increase in diffuse fraction significantly increases photosynthetic production in the canopy,but the mechanism has not been clarified.A three-dimensional light distribution model considering the geometry of incident radiation was employed in this study.This model was used to simulate the light distribution and potential photosynthetic production of rice canopy.The results indicate that the potential photosynthetic production of rice significantly increases in response to an increase in the diffuse fraction as long as global radiation does not decline greatly.The "fertilization effect" of diffuse radiation results from the reduction of leaf area with photosynthetic photon flux density(PPFD) below the light compensation point in response to an increasing diffuse fraction,and an increase in the leaf area with PPFD on the linear part of the light response curve.The increase in the diffuse fraction results in a significant increase in the photosynthetic rate of the upper canopy.High-performance computation is an easy-to-use and economic approach to overcome the computational constraints of the model.