剖面隐马氏模型训练算法的改进

利用剖面隐马氏模型获得多序列联配，一般需要经过初始化、训练、联配三个过程．然而，目前广泛采用的Baum—welch训练算法假设各条可观察序列互相独立，这与实际情况有所不符．本文对剖面隐马氏模型，给出可观察序列在互相不独立情况下的改进Baum—wlelch算法，在可观察序列两种特殊情况下（互相独立和一致依赖），得到了改进算法的具体表达式，讨论了一般情况下权重的选取方法．最后通过一个具体的蛋白质家族的多序列联配来说明改进算法的效果．     

与"求线性规划问题可行基的一种方法"的再商榷

再次说明文[1]提出的方法不能直接使用，仍须按文[2]的修正结果实行才是正确的。同时指出最近提出的某些算法的不实之处，以飨读者，避免误导。     

线性规划的约束条件“滚雪球”算法

为使线性规划的每个约束条件部分或全部地拥有原整个约束条件所包含的信息,将线性规划的约束条件“滚雪球”后得到与原约束条件等价的新约束条件,对新约束条件所构成的线性规划采用目标函数最速递减算法.有一定规模的随机数值算例显示了该算法只需进行m(约束条件数)次迭代即可求得最优解.     

A NEW ALGORITHM OF RELAXATION METHOD FOR PARTICLE ANALYSIS FROM FORWARD SCATTERED LIGHT

1. Introduction In many cases, particle dimension and size distribution play an important role in application. The analysis of parti- cle size is therefore necessary for research and develop- ment and also for process quality control in powder tech- nology and for many particle systems (Wang et al., 2000). Many instruments have been developed and constructed for this purpose. With the rapid development and availabil- ity of laser techniques, optoelectronics and microcomputer science, light sc…     

A polynomial-time algorithm for the change-making problem

Optimally making change—representing a given value with the fewest coins from a set of denominations—is in general NP-hard. In most real money systems however, the greedy algorithm is optimal. We give a polynomial-time algorithm to determine, for a given coin system, whether the greedy algorithm is optimal.     

An acyclic days-off scheduling problem

This paper studies the days off scheduling problem when the demand for staffing fluctuates from day to another and when the number of total workdays is fixed in advance for each employee. The scheduling problem is then to allocate rests to employees with different days off policies: (1) two or three consecutive days off for each employee per week and (2) at least three consecutive days off for each employee per month. For each one, we propose a polynomial time algorithm to construct a solution if it exists. Received: April 2005 / Revised version: October 2005 AMS classification: 60K25, 60K30     

Componentwise adaptation for high dimensional MCMC

Summary  We introduce a new adaptive MCMC algorithm, based on the traditional single component Metropolis-Hastings algorithm and on our earlier adaptive Metropolis algorithm (AM). In the new algorithm the adaption is performed component by component. The chain is no more Markovian, but it remains ergodic. The algorithm is demonstrated to work well in varying test cases up to 1000 dimensions.     

有预算限制的最大多种物资流问题

研究有预算限制的最大多种物资流问题,给出了这个问题的不依赖物资数k的全多项式时间近似算法,其算法复杂性是O~(-ε2m2).同时,利用有预算限制的最大多种物资流问题的研究结果,我们也得到了费用最小的最大多种物资流问题的近似算法和算法复杂性.     

关于零级亚纯函数的一类新的奇异方向

本文研究了平面上的亚纯函数的奇异方向,利用Tsuji’s的第二基本定理和几个已有的关于函数增长性估计的引理,证明了平面上的零级亚纯函数至少存在一条T方向,这种方向直接以特征函数为比较函数,克服了Borel方向的定义中关于增长级不能为零的限制.     

液晶相位可变延迟器对自旋极化电子束极化方向的调制

讨论了液晶相位可变延迟器（liquid crystal variable retarder, LCVR）在自旋极化电子产生方面的应用.LCVR控制入射光子的偏振度，从而实现对自旋极化电子束极化方向的调制.采用LCVR代替1/4波片和Pockels盒的优点在于其对入射光方向不敏感，传输直径大，不需要机械转动即可大波长范围的延迟，且易于校准.另外，还研制了旋转检偏器，通过示波器读出，对光子偏振性进行检测并对LCVR进行校准. 关键词： 自旋极化电子源 液晶相位可变延迟器 极化方向