求鳞状循环因子矩阵的极小多项式的算法

提出了任意域上鳞状循环因子矩阵 ,利用多项式环的理想的Go bner基的算法给出了任意域上鳞状循环因子矩阵的极小多项式和公共极小多项式的一种算法 .同时给出了这类矩阵逆矩阵的一种求法 .在有理数域或模素数剩余类域上 ,这一算法可由代数系统软件Co CoA4 .0实现 .数值例子说明了算法的有效性     

On the relation between a common gauge origin formulation and the GIAO formulation of the NMR shielding tensor

In this article the formal equivalence between the “gauge including atomic orbitals” (GIAO) and the simpler common gauge (cg) formulations of the nuclear magnetic resonance (NMR) shielding tensor is proven. To be able to give this proof, one has to assume exactly solved zeroth order quantum mechanical equations and complete basis sets. The proof of the equivalence has been known in the literature for some time (e.g. S.T. Epstein `The variation method in quantum chemistry', Academic Press, 1974). However, our approach has the advantage that, by comparing the GIAO and cg methods, it provides insight into the para- and diamagnetic contributions of the shielding. Thus, it yields justification for qualitative analysis schemes that have been used to explain trends in chemical shifts. Our formal proof is based on density functional theory. However, it is argued that very similar arguments should apply to other levels of theory as well. Received: 25 June 2002 / Accepted: 18 July 2002 / Published online: 15 October 2002 Acknowledgments. The author would like to acknowledge Tom Ziegler, Calgary, for numerous discussions on the subject. The reviewer is acknowledged for the insightful and detailed comments. Correspondence to: G. Schreckenbach e-mail: schrecke@alcor.concordia.ca     

菌陈挥发油GC-MS指纹图谱分析

建立了菌陈挥发油GC-MS指纹图谱，将正交投影算法用于不同样本中共有峰的提取，提高了共有峰的识别能力，降低了由于保留时间的漂移、质谱检索匹配度不高以及色谱峰重叠而引起的共有峰识别的难度．采用共有峰率、变异率及相似度等几个指标对4个不同产地的菌陈挥发油成分进行了评价，从共性、差异和整体性等多个方面全面表征菌陈挥发油的化学模式特征．结果表明，不同产地的菌陈挥发油成分大致相同，该指纹图谱可用于菌陈中挥发油成分的质量控制．     

A new sprout inhibitor of potato tuber based on carvone/β-cyclodextrin inclusion compound

A monoterpene, D-carvone or (4S)-(+)-carvone, present in the essential oil of caraway seeds (Carum carvi L.), acts as a sprouting inhibitor agent for potato tubers in storage. The aim of the present study was to investigate the possibility of using carvone/β-cyclodextrin inclusion compound as a sprout inhibitor agent for potato tubers. A Raman study of the interactions between β-cyclodextrin (β-CD) and included carvone molecule in solid state is also reported; the results confirm the synthesis of inclusion compound at pilot scale level.     

A common age effect model for the mortality of multiple populations

We introduce a model for the mortality rates of multiple populations. To build the proposed model we investigate to what extent a common age effect can be found among the mortality experiences of several countries and use a common principal component analysis to estimate a common age effect in an age–period model for multiple populations. The fit of the proposed model is then compared to age–period models fitted to each country individually, and to the fit of the model proposed by Li and Lee (2005).Although we do not consider stochastic mortality projections in this paper, we argue that the proposed common age effect model can be extended to a stochastic mortality model for multiple populations, which allows to generate mortality scenarios simultaneously for all considered populations. This is particularly relevant when mortality derivatives are used to hedge the longevity risk in an annuity portfolio as this often means that the underlying population for the derivatives is not the same as the population in the annuity portfolio.     

Tensor conditions for the existence of a common solution to the Lyapunov equation

Necessary and sufficient conditions for the existence of a common solution to the Lyapunov equation for two stable complex matrices are derived. These conditions are applied to the cases when a common weak solution to the Lyapunov equation exists. Conditions for the existence of a common solution to the Lyapunov equation for two complex 2 × 2 and two complex 3 × 3 matrices are derived.     

Analysis and design of switched normal systems

In this paper, we study the stability property for a class of switched linear systems whose subsystems are normal. The subsystems can be continuous-time or discrete-time ones. We show that when all the continuous-time subsystems are Hurwitz stable and all the discrete-time subsystems are Schur stable, a common quadratic Lyapunov function exists for the subsystems and thus the switched system is exponentially stable under arbitrary switching. We show that when unstable subsystems are involved, for a desired decay rate of the system, if the activation time ratio between stable subsystems and unstable ones is less than a certain value (calculated using the decay rate), then the switched system is exponentially stable with the desired decay rate.     

Meta-heuristic approaches for minimizing total earliness and tardiness penalties of single-machine scheduling with a common due date

This study addresses a class of single-machine scheduling problems involving a common due date where the objective is to minimize the total job earliness and tardiness penalties. A genetic algorithm (GA) approach and a simulated annealing (SA) approach utilizing a greedy local search and three well-known properties in the area of common due date scheduling are developed. The developed algorithms enable the starting time of the first job not at zero and were tested using a set of benchmark problems. From the viewpoints of solution quality and computational expenses, the proposed approaches are efficient and effective for problems involving different numbers of jobs, as well as different processing time, and earliness and tardiness penalties.     

Roll angle measurement based on common path compensation principle

We propose a novel and compact roll angle displacement measurement method based on collimated laser position measurement and the common path compensation principle. The principles of the roll angle displacement measurement and the common path compensation are analyzed. The feasibility of the measurement method is verified, and the experimental results revealed a linear correlation coefficient of 0.99995 between the relative displacement of the measuring beam spot and the angular displacement. Furthermore, the theoretical measurement resolution is 0.013  arcsec. To test the performance of the compensation, a series of experiments, including one system stability experiment and two different environmental interference experiments, were performed. The experimental results indicated that the standard deviations of the measuring beam spot’s angular drift were improved by 82.6–87.2%. Thus, the stability of the system and the measurement resolution were improved.     

Forecasting mortality in subpopulations using Lee–Carter type models: A comparison

The relative performance of multipopulation stochastic mortality models is investigated. When targeting mortality rates, we consider five extensions of the well known Lee–Carter single population extrapolative approach. As an alternative, we consider similar structures when mortality improvement rates are targeted. We use a dataset of deaths and exposures of Italian regions for the years 1974–2008 to conduct a comparison of the models, running a battery of tests to assess the relative goodness of fit and forecasting capability of different approaches. Results show that the preferable models are those striking a balance between complexity and flexibility.